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National Nosocomial Infections Surveillance (NNIS) System Report, data summary from January 1992 through June 2004, issued October 2004

      This report is a summary of the data collected and reported by hospitals participating in the National Nosocomial Infections Surveillance (NNIS) System from January 1992 through June 2004 and updates previously published data.
      • CDC NNIS System
      National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992 to June 2003, issued August 2003.
      • Jarvis W.R.
      • Edwards J.R.
      • Culver D.H.
      • Hughes J.M.
      • Horan T.
      • Emori T.G.
      • et al.
      Nosocomial infection rates in adult and pediatric intensive care units in the United States.
      • Gaynes R.P.
      • Martone W.J.
      • Culver D.H.
      • Emori T.G.
      • Horan T.C.
      • Banerjee S.N.
      • et al.
      Comparison rates of nosocomial infections in neonatal intensive care units in the United States.
      • Culver D.H.
      • Horan T.C.
      • Gaynes R.P.
      • Martone W.J.
      • Jarvis W.R.
      • Emori T.G.
      • et al.
      Surgical wound infection rates by wound class, operative procedure, and patient risk index.
      The NNIS System was established in 1970 when selected hospitals in the United States routinely began reporting their nosocomial infection surveillance data for aggregation into a national database. Hospitals participating in the NNIS System provide general medical-surgical inpatient services to adults or children requiring acute care. Identity of the nearly 300 hospitals currently participating in the NNIS System is confidential.
      All NNIS data are collected using standardized protocols, called “surveillance components”: adult and pediatric intensive care unit (ICU), high-risk nursery (HRN), and surgical patient.
      • Emori T.G.
      • Culver D.H.
      • Horan T.C.
      • Jarvis W.R.
      • White J.W.
      • Olson D.R.
      • et al.
      National nosocomial infections surveillance (NNIS) system: description of surveillance methodology.
      • Horan T.C.
      • Gaynes R.P.
      Surveillance of nosocomial infections.
      • Horan T.C.
      • Emori T.G.
      Definitions of key terms used in the NNIS system.
      The components may be used singly or simultaneously, but once selected, they must be used for a minimum of 1 calendar month. All infections are categorized into major and specific infection sites using standard CDC definitions that include laboratory and clinical criteria.
      • Horan T.C.
      • Gaynes R.P.
      Surveillance of nosocomial infections.

      Adult and pediatric ICU surveillance component

      Infection control professionals (ICPs) collect data on all sites of nosocomial infection in patients located in ICUs, as well as ICU-specific denominator data. Site-specific infection rates can be calculated by using as a denominator the number of patients at risk, patient-days, and days of indwelling urinary catheterization, central vascular cannulation (central line), or ventilation.

      HRN surveillance component

      ICPs collect data on all sites of nosocomial infection in patients located in HRN, and HRN-specific denominator data. Site-specific infection rates can be calculated by using as a denominator the number of patients at risk, patient-days, and days of umbilical catheter/central line use or ventilation for each of 4 birth-weight categories (≤1000 gm, 1001–1500 gm, 1501–2500 gm, and ≥2500 gm).

      Surgical patient surveillance component

      ICPs select from the NNIS operative procedure list those procedures they wish to follow up and monitor the patients undergoing those procedures for all infections or surgical site infections (SSI) only. A record on every patient undergoing the selected procedure is generated that includes information on risk factors for SSI such as wound class,
      • Mangram A.J.
      • Horan T.C.
      • Pearson M.L.
      • Silver L.C.
      • Jarvis W.R.
      Guideline for prevention of surgical site infection, 1999.
      duration of operation, and American Society of Anesthesiology (ASA) score.
      • Owens W.D.
      • Felts J.A.
      • Spitznagel Jr., E.L.
      ASA physical status classification: a study of consistency of ratings.
      Using a composite index for predicting the risk of SSI after operation, ICPs can calculate rates by the number of risk factors present.
      • Culver D.H.
      • Horan T.C.
      • Gaynes R.P.
      • Martone W.J.
      • Jarvis W.R.
      • Emori T.G.
      • et al.
      Surgical wound infection rates by wound class, operative procedure, and patient risk index.
      The time periods for the data contained in this report vary depending on the table. Each table represents NNIS data from one of the surveillance components. For the ICU and HRN surveillance components where data volume was large after risk stratification, we were able to construct tables comprised of data from fewer and more recent years only (January 2002 through June 2004; Table 1, Table 2, Table 3, Table 4). However for the surgical patient component, we had to use all the data from January 1992 through June 2004, because the numbers of operations in each procedure-risk-stratum was too small to produce stable rates when only more recent years' data were used (Table 5, Table 6, Table 7, Table 8). Similarly, Table 9, Table 10 required use of data reported since January 1998 through June 2004.
      Table 1Pooled means and percentiles of the distribution of device-associated infection rates, by type of ICU, ICU component, January 2002 through June 2004
      Urinary catheter-associated UTI rate
      Number of urinary catheter-associated UTIsNumber of urinary catheter-days×1000
      Percentile
      Type of ICUNo. of unitsUrinary catheter-daysPooled mean10%25%50% (median)75%90%
      Coronary60170,7594.50.82.64.07.510.2
      Cardiothoracic48193,4243.00.01.12.43.96.2
      Medical94448,1615.10.72.54.77.19.5
      Medical-surgical
       Major teaching99593,1003.91.32.13.35.27.5
       All others108757,5313.30.61.63.15.16.9
      Neurosurgical2999,0396.71.83.16.07.89.5
      Pediatric52104,7884.00.01.63.66.18.1
      Surgical99486,5754.41.42.33.86.58.8
      Trauma22104,1816.02.13.85.77.39.3
      Burn1444,3426.7
      Respiratory617,7846.4
      Central line-associated BSI rate
      Number of central line-associated BSIsNumber of central line-days×1000
      Percentile
      Type of ICUNo. of unitsCentral line-daysPooled mean10%25%50% (median)75%90%
      Coronary60116,5463.51.01.53.27.09.0
      Cardiothoracic48182,4072.70.00.91.82.74.9
      Medical94312,4785.00.52.43.96.48.8
      Medical-surgical
       Major teaching100430,9794.01.72.63.45.17.6
       All others109486,1153.20.81.63.14.36.1
      Neurosurgical3056,6454.60.00.93.15.810.6
      Pediatric54161,3146.60.93.05.28.111.2
      Surgical99358,5784.60.02.03.45.98.7
      Trauma2270,3727.41.93.35.28.211.9
      Burn1443,0027.0
      Respiratory612,5934.8
      Ventilator-associated pneumonia rate
      Number of ventilator-associated pneumoniasNumber of ventilator-days×1000
      Percentile
      Type of ICUNo. of unitsVentilator-daysPooled mean10%25%50% (median)75%90%
      Coronary5976,1454.40.01.94.06.89.8
      Cardiothoracic4798,3587.21.22.96.312.615.5
      Medical92268,5184.90.52.13.76.28.9
      Medical-surgical
       Major teaching99320,9165.41.22.64.67.29.9
       All others109351,7055.11.72.95.16.78.9
      Neurosurgical2945,07311.20.02.46.213.516.8
      Pediatric52133,9952.90.00.92.34.88.1
      Surgical98253,9009.32.24.78.312.217.9
      Trauma2263,13715.24.38.011.416.625.3
      Burn1423,11712.0
      Respiratory618,8384.9
      UTI, Urinary tract infection; BSI, bloodstream infection.
      Number of urinary catheter-associated UTIsNumber of urinary catheter-days×1000
      Number of central line-associated BSIsNumber of central line-days×1000
      Number of ventilator-associated pneumoniasNumber of ventilator-days×1000
      Table 2Pooled means and percentiles of the distribution of device utilization ratios, by type of ICU, ICU component, January 2002 through June 2004
      Urinary catheter utilization
      Number of urinary catheter-daysNumber of patient-days
      Percentile
      Type of ICUNo. of unitsPatient-daysPooled mean10%25%50% (median)75%90%
      Coronary60305,9110.560.260.460.600.700.78
      Cardiothoracic48230,4870.840.580.760.880.950.96
      Medical94596,5880.750.580.650.760.830.88
      Medical-surgical
       Major teaching99759,4640.780.650.740.820.870.90
       All others108979,5500.770.670.730.780.840.87
      Neurosurgical29116,9310.850.650.760.820.920.95
      Pediatric53349,2580.300.110.200.300.410.47
      Surgical99590,2200.820.650.760.860.920.96
      Trauma22115,0990.910.770.850.930.960.98
      Burn1476,8770.58
      Respiratory626,5670.67
      Central line utilization
      Number of central line-daysNumber of patient-days
      Percentile
      Type of ICUNo. of unitsPatient-daysPooled mean10%25%50% (median)75%90%
      Coronary60305,9110.380.150.220.360.510.60
      Cardiothoracic48230,4870.790.550.700.830.870.93
      Medical95596,5880.520.310.370.520.640.75
      Medical-surgical
       Major teaching100759,4640.570.360.470.560.660.74
       All others109979,5500.500.290.380.490.580.66
      Neurosurgical30116,9310.480.230.330.500.550.65
      Pediatric54349,2580.460.200.310.460.570.64
      Surgical100590,2200.610.340.520.630.720.81
      Trauma22115,0990.610.400.490.600.710.79
      Burn1476,8770.56
      Respiratory626,5670.47
      Ventilator utilization
      Number of ventilator-daysNumber of patient-days
      Percentile
      Type of ICUNo. of unitsPatient-daysPooled mean10%25%50% (median)75%90%
      Coronary60305,9110.250.110.140.230.360.41
      Cardiothoracic48230,4870.430.250.310.400.480.58
      Medical94596,5880.460.220.320.460.570.67
      Medical-surgical
       Major teaching99759,4640.430.230.320.430.550.62
       All others109979,5500.370.220.280.350.420.52
      Neurosurgical29116,9310.390.190.260.340.450.56
      Pediatric52349,2580.390.170.250.360.490.57
      Surgical99590,2200.440.190.310.460.530.65
      Trauma22115,0990.560.390.440.500.670.77
      Burn1476,8770.31
      Respiratory626,5670.71
      Number of urinary catheter-daysNumber of patient-days
      Number of central line-daysNumber of patient-days
      Number of ventilator-daysNumber of patient-days
      Table 3Pooled means and percentiles of the distribution of device-associated infection rates, by birth-weight category, HRN component, January 2002 through June 2004
      Umbilical and central line-associated BSI rate
      Number of umbilical and central line-associated BSIsNumber of umbilical and central line-days×1000
      Percentile
      Birth-weight categoryNo. of HRNsCentral line-daysPooled mean10%25%50% (median)75%90%
      ≤1000 g104204,4689.11.65.48.511.616.1
      1001–1500 g9895,2545.40.01.84.07.412.2
      1501–2500 g9779,9044.10.00.03.26.58.9
      >2500 g9497,2023.50.00.01.94.17.4
      Ventilator-associated pneumonia rate
      Number of ventilator-associated pneumoniaNumber of ventilator-days×1000
      Percentile
      Birth-weight categoryNo. of HRNsVentilator-daysPooled mean10%25%50% (median)75%90%
      ≤1000 g102204,1173.50.00.02.45.88.5
      1001–1500 g9150,2042.40.00.00.03.28.0
      1501–2500 g8639,9571.90.00.00.01.56.1
      >2500 g9055,0381.40.00.00.00.93.2
      BSI, Bloodstream infection.
      Number of umbilical and central line-associated BSIsNumber of umbilical and central line-days×1000
      Number of ventilator-associated pneumoniaNumber of ventilator-days×1000
      Table 4Pooled means and percentiles of the distribution of device utilization ratios, by birth-weight category, HRN component, January 2002 through June 2004
      Umbilical and central line utilization ratio
      Number of umbilical and central line-daysNumber of patient-days
      Percentile
      Birth-weight categoryNo. of HRNsPatient-daysPooled mean10%25%50% (median)75%90%
      ≤1000 g105489,1950.420.210.310.430.550.70
      1001–1500 g104319,3160.300.080.160.290.460.58
      1501–2500 g103388,6300.210.050.090.170.310.54
      >2500 g103335,4300.290.060.120.200.410.54
      Ventilator utilization ratio
      Number of ventilator-daysNumber of patient-days
      Percentile
      Birth-weight categoryNo. of HRNsPatient-daysPooled mean10%25%50% (median)75%90%
      ≤1000 g105489,1950.430.220.320.430.530.63
      1001–1500 g104319,3160.160.050.090.150.200.35
      1501–2500 g103388,6300.100.030.050.070.160.27
      >2500 g103335,4300.170.040.060.110.210.33
      Number of umbilical and central line-daysNumber of patient-days
      Number of ventilator-daysNumber of patient-days
      Table 5SSI rates
      Per 100 operations.
      , by operative procedure and risk index category, Surgical Patient component, January 1992 through June 2004
      Operative procedure categoryDuration cut point (h)Risk index categoryNRateRisk index categoryNRateRisk index categoryNRateRisk index categoryNRate
      CARDCardiac5021470.70149,1351.502,315,2152.21
      CBGBCABG-chest and donor site5027181.251380,3403.39282,5355.4332469.76
      CBGCCABG-chest only401600.00115,2482.192,36,4993.72
      OCVSOther cardiovascular20,111,2330.60238281.2831533.92
      ORESOther respiratory20,1,2,317282.43
      THORThoracic3014230.42152500.992,31,9842.47
      APPYSee Table 7
      BILILiver/pancreas504823.111,2,317367.37
      CHOLSee Table 7
      COLOSee Table 7
      GASTSee Table 7
      OGITOther digestive2014181.90125593.012,31,1085.69
      SBSmall bowel3017494.97142187.1122,1448.63336211.60
      XLAPLaparotomy2064141.71180823.0824,5424.7139877.19
      NEPHNephrectomy40,1,2,337471.04
      OGUOther genitourinary2013,8310.36178960.852,31,9532.92
      PRSTProstatectomy4027320.811,2,323892.05
      HNHead and neck706602.2719625.302,340812.50
      OENTOther ENT3029090.07113890.722,33072.61
      HERHerniorrhaphy2012,6590.81183972.142,32,0334.53
      MASTMastectomy3016,2871.74110,7002.202,31,1123.42
      CRANCraniotomy4047170.91114,8641.722,34,6662.40
      ONSOther nervous system40,1,2,323561.53
      VSHNVentricular shunt2042084.421,2,312,3245.36
      CSECCesarean section10154,1412.71146,0814.142,34,8717.53
      HYSTAbdominal hysterectomy2049,0241.36124,0642.322,35,0535.17
      OOBOther obstetric10,1,2,313630.51
      VHYSVaginal hysterectomy20,1,2,329,8571.31
      AMPLimb amputation20,1,2,310,7323.50
      FUSNSpinal fusion4051,0571.04130,6192.642,38,1226.35
      FXOpen reduction of fracture2016,1420.79126,3721.4125,0812.8135234.97
      HPROHip prosthesis2044,4540.86171,3361.652,318,9412.52
      KPROKnee prosthesis2066,3600.88174,0291.282,318,0512.26
      LAMLaminectomy2073,8460.88155,5171.352,318,1062.46
      OMSOther musculoskeletal3018,8050.63113,5270.942,33,9271.78
      OPROOther prosthesis30,1,2,338820.62
      OBLOther hem/lymph system30,1,2,310501.90
      OESOther endocrine system3026070.151,2,320430.78
      OEYEOther eye30,1,2,35930.67
      OSKNOther integumentary system20,1,2,395891.29
      SKGRSkin graft3012880.93121551.722,31,5264.19
      SPLESplenectomy30,1,2,316092.80
      TPOrgan transplant60,149644.632182413.7135026.00
      VSVascular3079010.90170,7171.722,328,4584.34
      CBGB, Coronary artery bypass graft with chest and donor site incisions (eg, femoral or radial artery harvested as donor vessel for bypass graft); CBGC, coronary artery bypass graft with chest incision only (eg, use of internal mammary artery for bypass graft); ENT, ear, nose, and throat.
      Per 100 operations.
      Table 6Percentiles of the distribution of SSI rates,
      Per 100 operations.
      by operative procedure and risk index category,
      Includes only those procedure-risk categories for which at least 20 hospitals have reported at least 20 operations.
      Surgical Patient component, January 1992 through June 2004
      Percentile
      Operative procedure categoryRisk index categoryNo. hospitalsPooled mean rate10%25%50% (median)75%90%
      CARDCardiac11091.5000.471.21.782.91
      CARDCardiac2,3882.21001.473.034.67
      CBGBCABG-chest and donor site0331.25000.492.143.38
      CBGBCABG-chest and donor site11843.391.562.173.174.366.02
      CBGBCABG-chest and donor site21745.432.283.645.167.649.86
      CBGCCABG-chest only11072.19001.513.434.36
      CBGCCABG-chest only2,3693.7200.992.444.477.02
      OCVSOther cardiovascular0,1360.600000.671.83
      OCVSOther cardiovascular2231.280001.12.33
      THORThoracic0210.4200002.34
      THORThoracic1370.990001.32.73
      THORThoracic2,3222.47001.643.546.04
      APPYAppendectomyM220.670000.741.38
      APPYAppendectomy0471.31001.132.053.24
      APPYAppendectomy1582.5501.282.223.295.78
      APPYAppendectomy2,3394.8501.633.975.9710.15
      CHOLCholecystectomyM880.450000.531.17
      CHOLCholecystectomy0920.68000.41.122.38
      CHOLCholecystectomy1761.78001.323.115.12
      CHOLCholecystectomy2463.2700.563.234.656.6
      COLOColonM0993.9801.933.2256.42
      COLOColon11075.661.913.365.16.978.96
      COLOColon2848.543.925.489.0911.6217.16
      COLOColon32811.252.116.6713.3316.2221.67
      GASTGastric0292.58002.584.225.98
      GASTGastric1534.690.211.894.216.979.41
      GASTGastric2,3348.340.853.647.2712.5219.41
      OGITOther digestive1223.01002.133.376.45
      SBSmall bowel0274.9702.584.776.088.71
      SBSmall bowel1377.112.454.345.97.6911.12
      SBSmall bowel2288.634.635.567.521216.78
      XLAPLaparotomy0391.71001.292.192.87
      XLAPLaparotomy1453.0801.142.423.936.7
      XLAPLaparotomy2354.7101.653.826.6710.17
      NEPHNephrectomy0,1,2,3281.04000.852.334.98
      OGUOther genitourinary0330.36000.140.521.3
      OGUOther genitourinary1290.85000.51.892.36
      PRSTProstatectomy0310.810000.792.1
      PRSTProstatectomy1,2,3252.05000.933.694.65
      HERHerniorrhaphy0510.81000.822.83
      HERHerniorrhaphy1532.1400.811.923.665.96
      HERHerniorrhaphy2,3274.53003.825.767.41
      MASTMastectomy0591.74000.691.613.04
      MASTMastectomy1532.2000.752.073.86.38
      CRANCraniotomy0420.910001.873.79
      CRANCraniotomy1701.72001.042.394.05
      CRANCraniotomy2,3482.40001.33.455.56
      ONSOther nervous system0,1,2,3201.530001.752.33
      VSHNVentricular shunt0304.42002.634.838.17
      VSHNVentricular shunt1,2,3445.3601.493.456.068.61
      CSECCesarean section01302.710.421.262.174.326.74
      CSECCesarean section11174.1401.423.195.538.07
      CSECCesarean section2,3517.5302.425.3810.3913.62
      HYSTAbdominal hysterectomy01071.36000.912.183.44
      HYSTAbdominal hysterectomy11002.3200.71.963.334.65
      HYSTAbdominal hysterectomy2,3535.1702.064.218.319.93
      VHYSVaginal hysterectomy0,1,2,3711.3100.280.911.983.92
      AMPLimb amputation0,1,2,3403.5001.272.865.37.41
      FUSNSpinal fusion01101.04000.681.382.46
      FUSNSpinal fusion11142.6400.832.163.54.72
      FUSNSpinal fusion2,3776.3502.344.787.2710.19
      FXOpen reduction of fracture0680.79000.31.161.89
      FXOpen reduction of fracture1761.410011.682.47
      FXOpen reduction of fracture2462.8101.022.74.456.4
      HPROHip prosthesis01620.86000.51.212.17
      HPROHip prosthesis11891.6500.361.412.253.33
      HPROHip prosthesis2,31532.5200.752.063.75.63
      KPROKnee prosthesis01620.88000.661.282.29
      KPROKnee prosthesis11791.2800.291.091.862.86
      KPROKnee prosthesis2,31522.2600.742.043.575.94
      LAMLaminectomy01330.88000.591.352.59
      LAMLaminectomy11371.3500.491.351.893.05
      LAMLaminectomy2,31102.4601.092.113.525.22
      OMSOther musculoskeletal0440.63000.340.811.36
      OMSOther musculoskeletal1450.94000.541.392.32
      OMSOther musculoskeletal2,3231.7800.351.583.514.31
      OPROOther prosthesis0,1,2,3290.620000.592.2
      OESOther endocrine system0200.1500000.27
      OSKNOther integumentary system0,1,2,3291.2900.441.031.732.55
      SPLESplenectomy0,1,2,3202.80002.224.416.13
      TPOrgan transplant0,1204.631.1122.995.149.66
      VSVascular0700.900001.713.28
      VSVascular11101.7200.811.542.663.81
      VSVascular2,31034.341.012.984.796.678.38
      CBGB, Coronary artery bypass graft with chest and donor site incisions (eg, femoral or radial artery harvested as donor vessel for bypass graft); CBGC, coronary artery bypass graft with chest incision only (eg, use of internal mammary artery for bypass graft).
      Per 100 operations.
      Includes only those procedure-risk categories for which at least 20 hospitals have reported at least 20 operations.
      Table 7SSI rates,
      Per 100 operations.
      by selected operative procedure and modified risk index category incorporating laparoscope use,
      This table uses a modified risk index that incorporates the influence of laparoscope on SSI rates. The influence of scope on SSI rates was different across the 4 procedures: For cholecystectomy and colon operation, when the operation was done laparoscopically, 1 was subtracted from the number of risk factors present (ASA score of 3, 4, or 5; duration of surgery >75th percentile; or contaminated or dirty wound class) in the NNIS risk index. For example, when 2 risk factors were present and the procedure was done laparoscopically, the new modified risk index category is 1 (ie, 2 – 1=1). When no risk factors were present and the procedure was performed with a laparoscope (ie, 0 – 1=−1), we designated this new modified risk category as –1 or “M”. For appendectomy and gastric operations, the use of a scope was important only if the patient had no other risk factors. We split patients with no other risk factors into two groups: 0-Yes (laparoscope used) and 0-No (laparoscope not used).
      Surgical Patient component, January 1992 through June 2004
      Operative procedure categoryDuration cut point (h)Risk index categoryNRateRisk index categoryNRateRisk index categoryNRateRisk index categoryNRateRisk index categoryNRate
      CHOL Cholecystectomy2M33,7890.45027,5790.68112,8041.78244603.2734755.68
      COLO Colon3M,020,6373.98133,5275.66213,7778.543187611.25
      APPY Appendectomy10–Yes31460.670–No82201.31111,2222.552,342914.85
      GAST Gastric30–Yes7320.680–No35222.58172534.692,333458.34
      Per 100 operations.
      This table uses a modified risk index that incorporates the influence of laparoscope on SSI rates. The influence of scope on SSI rates was different across the 4 procedures: For cholecystectomy and colon operation, when the operation was done laparoscopically, 1 was subtracted from the number of risk factors present (ASA score of 3, 4, or 5; duration of surgery >75th percentile; or contaminated or dirty wound class) in the NNIS risk index. For example, when 2 risk factors were present and the procedure was done laparoscopically, the new modified risk index category is 1 (ie, 2 – 1 = 1). When no risk factors were present and the procedure was performed with a laparoscope (ie, 0 – 1 = −1), we designated this new modified risk category as –1 or “M”. For appendectomy and gastric operations, the use of a scope was important only if the patient had no other risk factors. We split patients with no other risk factors into two groups: 0-Yes (laparoscope used) and 0-No (laparoscope not used).
      Table 8SSI rates
      Per 100 operations.
      following coronary artery bypass graft (CBGB) operation, by risk index category and specific site, Surgical Patient component, January 1992 through June 2004
      Risk index category0123
      Infection siteNo. SSIsRateNo. SSIsRateNo. SSIsRateNo. SSIsRate
      Leg (Donor Site)200.7454361.4320242.4552.03
      Superficial incisional150.5542031.1015771.9152.03
      Deep incisional50.1812330.324470.5400.00
      Chest140.5174401.9624592.98197.72
      Superficial incisional70.2627960.749331.1352.03
      Deep incisional40.1520910.556270.7693.66
      Organ/space30.1125530.678991.0952.03
      Total341.2512,8763.3944835.43249.76
      Denominators for the risk categories are as follows: Category 0 = 2718; Category 1 = 380,340; Category 2 = 82,535; Category 3 = 246.
      Per 100 operations.
      Table 9Pooled means and percentiles of the distribution of antimicrobial usage rates (defined daily dose
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      rates
      DDD per 1000 patient-days=DDD of specific agent usedTotal number of patient-days×1000
      ), by non-ICU inpatient areas and various types of ICU, ICARE/AUR, January 1998 through June 2004
      Non-ICU Inpatient Areas (n = 74)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group759,86660.99.216.728.963.896.5
      Ampicillin group1,899,047152.183.2111.1141.7186.3266.9
      Antipseudomonal penicillins251,03620.13.18.116.429.042.9
      Antistaphylococcal penicillins245,77719.72.95.112.524.235.8
      First-generation cephalosporins982,57378.743.957.476.1106.6125.1
      Second-generation cephalosporins368,97029.610.316.525.341.554.9
      Third-generation cephalosporins793,34063.521.932.253.679.592.5
      Carbapenem group85,7796.90.41.84.79.417.1
      Aztreonam34,0782.70.10.71.84.36.4
      Fluoroquinolones1,166,83693.537.957.991.7130.3202.2
      Trimethoprim/sulfamethoxazole595,24847.75.314.824.539.2106.3
      Vancomycin (oral)38,2793.10.10.51.42.54.2
      Vancomycin (parenteral)415,88733.313.117.124.641.065.7
      Coronary Care Unit (n = 32)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group429630.80.00.47.241.7106.4
      Ampicillin group12,35688.58.644.888.3172.1245.9
      Antipseudomonal penicillins459932.90.03.320.842.858.6
      Antistaphylococcal penicillins367926.30.03.612.046.268.2
      First-generation cephalosporins697850.09.027.736.554.4104.9
      Second-generation cephalosporins428630.71.57.119.832.542.4
      Third-generation cephalosporins12,54089.825.132.873.598.0143.5
      Carbapenem group163511.70.00.26.112.127.4
      Aztreonam7775.60.00.02.010.814.9
      Fluoroquinolones12,39088.711.327.358.9112.3214.4
      Trimethoprim/sulfamethoxazole558540.00.06.016.543.4112.8
      Vancomycin (oral)5263.80.00.00.01.37.0
      Vancomycin (parenteral)771355.211.219.836.989.3105.9
      Cardiothoracic ICU (n = 21)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group373638.40.00.04.840.983.0
      Ampicillin group704472.43.316.658.597.6143.2
      Antipseudomonal penicillins213922.01.46.316.132.145.4
      Antistaphylococcal penicillins248325.50.00.06.431.038.6
      First-generation cephalosporins25,925266.636.5210.3258.7465.4697.9
      Second-generation cephalosporins899792.52.76.822.773.4470.1
      Third-generation cephalosporins894191.917.832.261.897.0151.1
      Carbapenem group166317.10.01.611.818.949.4
      Aztreonam7407.60.00.51.95.39.2
      Fluoroquinolones806582.98.623.265.5101.4187.4
      Trimethoprim/sulfamethoxazole160116.50.00.58.821.843.9
      Vancomycin (oral)5575.70.00.00.02.510.7
      Vancomycin (parenteral)12,081124.226.045.697.0156.9210.9
      Hematology/Oncology/Transplant Wards (n = 17)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group341627.6
      Ampicillin group17,578141.8
      Antipseudomonal penicillins3,59929.0
      Antistaphylococcal penicillins197515.9
      First-generation cephalosporins601748.5
      Second-generation cephalosporins290423.4
      Third-generation cephalosporins27,434221.3
      Carbapenem group186315.0
      Aztreonam9357.5
      Fluoroquinolones20,690166.9
      Trimethoprim/sulfamethoxazole400332.3
      Vancomycin (oral)5404.4
      Vancomycin (parenteral)10,17282.1
      Medical ICU (n = 36)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group11,59855.10.04.939.163.097.5
      Ampicillin group46,702222.089.4135.5181.4253.0345.4
      Antipseudomonal penicillins14,88770.813.130.660.4104.0170.5
      Antistaphylococcal penicillins936844.50.03.525.143.684.9
      First-generation cephalosporins745635.410.619.530.739.570.3
      Second-generation cephalosporins598628.51.27.021.747.967.1
      Third-generation cephalosporins53,488254.258.288.8140.2199.3317.3
      Carbapenem group788937.50.08.023.237.298.3
      Aztreonam19959.50.01.56.111.817.7
      Fluoroquinolones35,393168.239.382.5134.0184.4307.7
      Trimethoprim/sulfamethoxazole22,058104.80.021.640.591.7185.3
      Vancomycin (oral)3661.70.00.00.31.86.7
      Vancomycin (parenteral)27,921132.742.956.979.0156.4222.1
      Medical-surgical ICU (n = 61)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group21,83746.50.02.313.638.7113.4
      Ampicillin group94,566201.433.179.1185.0300.8376.9
      Antipseudomonal penicillins35,47175.518.237.261.795.4115.5
      Antistaphylococcal penicillins12,07925.71.44.813.829.349.0
      First-generation cephalosporins48,262102.823.953.576.7126.6209.2
      Second-generation cephalosporins16,10734.32.66.419.042.591.7
      Third-generation cephalosporins67,688144.161.280.4116.4163.4200.6
      Carbapenem group17,72737.83.48.226.847.062.9
      Aztreonam478510.20.01.96.214.023.9
      Fluoroquinolones96,695205.955.492.8167.5301.2360.3
      Trimethoprim/sulfamethoxazole31,44867.00.011.524.268.6203.4
      Vancomycin (oral)28686.10.00.02.45.99.3
      Vancomycin (parenteral)40,30385.833.153.266.7122.9143.0
      Neurosurgical ICU (n = 11)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group329455.6
      Ampicillin group6892116.3
      Antipseudomonal penicillins266945.0
      Antistaphylococcal penicillins429672.5
      First-generation cephalosporins6949117.2
      Second-generation cephalosporins115719.5
      Third-generation cephalosporins7339123.8
      Carbapenem group182130.7
      Aztreonam821.4
      Fluoroquinolones575497.1
      Trimethoprim/sulfamethoxazole383564.7
      Vancomycin (oral)741.2
      Vancomycin (parenteral)592399.9
      Surgical ICU (n = 37)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group17,16756.30.08.134.771.1109.8
      Ampicillin group63,393207.843.0100.5222.5305.7445.1
      Antipseudomonal penicillins16,71154.810.131.049.480.7102.2
      Antistaphylococcal penicillins910729.90.72.917.935.688.4
      First-generation cephalosporins54,317178.138.9101.2157.0365.5498.0
      Second-generation cephalosporins808126.53.412.829.447.469.2
      Third-generation cephalosporins45,082147.834.471.399.9116.7180.7
      Carbapenem group15,38350.41.010.319.654.974.6
      Aztreonam17805.80.44.17.111.519.3
      Fluoroquinolones46,268151.752.273.5131.2211.0291.1
      Trimethoprim/sulfamethoxazole22,81674.85.310.023.954.8179.9
      Vancomycin (oral)12724.20.00.00.83.111.3
      Vancomycin (parenteral)48,435158.845.465.999.1155.3196.0
      Pediatric ICU (n = 16)Percentile
      Antimicrobial agentNo. DDD
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      Pooled mean10%25%50% (median)75%90%
      Penicillin group216241.6
      Ampicillin group481892.7
      Antipseudomonal penicillins57511.1
      Antistaphylococcal penicillins182935.2
      First-generation cephalosporins253148.7
      Second-generation cephalosporins169032.5
      Third-generation cephalosporins7564145.6
      Carbapenem group4218.1
      Aztreonam901.7
      Fluoroquinolones66812.8
      Trimethoprim/sulfamethoxazole90817.5
      Vancomycin (oral)1603.1
      Vancomycin (parenteral)332964.1
      Defined daily dose (DDD) of antimicrobial agent is calculated by dividing the total grams of the antimicrobial agent used in a hospital area by the number of grams in an average daily dose of the agent given to an adult patient.
      DDD per 1000 patient-days=DDD of specific agent usedTotal number of patient-days×1000
      Table 10Pooled means and percentiles of the distribution of antimicrobial resistance rates
      For each antimicrobial agent and pathogen combination, resistance rates were calculated as: Number of resistant isolatesNumber of isolates tested×100
      , by all ICUs combined, non-ICU inpatient units and by outpatients, ICARE/AUR, January 1998 through June 2004
      All ICUs combinedPercentile
      Antimicrobial-resistant pathogenNo. unitsNo. testedPooled mean10%25%50% (median)75%90%
      MRSA15722,89952.9020.032.748.160.367.9
      Methicillin-resistant CNS14113,55376.6057.069.476.383.888.4
      Vancomycin-resistant Enterococcus spp14014,14013.900513.624.339.2
      Ciprofloxacin/ofloxacin-resistant Pseudomonas aeruginosa13413,47334.808.317.429.341.351.6
      Levofloxacin-resistant P aeruginosa68589535.309.718.229.140.847.7
      Imipenem-resistant P aeruginosa12311,98619.104.88.313.225.538
      Ceftazidime-reisistant P aeruginosa12912,80513.900510.816.923.6
      Piperacillin-resistant P aeruginosa11811,64017.502.47.514.319.531.4
      Cef3-resistant Enterobacter spp111532827.7010.017.426.136.447.4
      Carbapenem-resistant Enterobacter spp9346630.7000003.8
      Cef3-resistant Klebsiella pneumoniae11975296.20002.08.020.7
      Cef3-resistant Escherichia coli14012,0111.300002.66.5
      Quinolone-resistant E coli13611,7767.30003.38.219.4
      Penicillin-resistant pneumococci46133118.9005.31324.050.0
      Cefotaxime/ceftriaxone-resistant pneumococci338547.50003.49.628.0
      Non-ICU Inpatient AreasPercentile
      Antimicrobial-resistant pathogenNo. unitsNo. testedPooled mean10%25%50% (median)75%90%
      MRSA5642,50246.0025.631.944.952.060.8
      Methicillin-resistant CNS5323,52565.7052.257.165.271.175.9
      Vancomycin-resistant Enterococcus spp5532,92412.001.93.57.114.218.6
      Ciprofloxacin/ofloxacin-resistant Pseudomonas aeruginosa5521,30227.701320.527.436.840.6
      Levofloxacin-resistant P aeruginosa3010,07730.5015.621.828.733.344.1
      Imipenem-resistant P aeruginosa5317,14212.305.66.810.014.420.6
      Ceftazidime-reisistant P aeruginosa5319,5878.801.94.07.011.014.1
      Piperacillin-resistant P aeruginosa5316,82811.603.46.59.214.018.3
      Cef3-resistant Enterobacter spp50750921.007.713.920.725.730.9
      Carbapenem-resistant Enterobacter spp4659761.000001.23.2
      Cef3-resistant Klebsiella pneumoniae5514,2045.8000.21.54.414.5
      Cef3-resistant Escherichia coli5540,7511.50000.61.73.2
      Quinolone-resistant E coli5640,6948.200.41.83.67.018.9
      Penicillin-resistant pneumococci41362918.202.65.912.020.031.8
      Cefotaxime/ceftriaxone-resistant pneumococci3421487.6000.95.210.516.3
      Outpatient AreasPercentile
      Antimicrobial-resistant pathogenNo. unitsNo. testedPooled mean10%25%50% (median)75%90%
      MRSA4935,48931.1015.019.324.630.849.7
      Methicillin-resistant CNS4816,05450.2038.543.148.957.861.5
      Vancomycin-resistant Enterococcus spp4624,8404.600.81.33.66.19.3
      Ciprofloxacin/ofloxacin-resistant Pseudomonas aeruginosa4714,88123.4013.017.023.134.139
      Levofloxacin-resistant P aeruginosa24638824.5012.515.120.330.734.8
      Imipenem-resistant P aeruginosa4611,7697.003.04.06.49.213
      Ceftazidime-reisistant P aeruginosa4613,4074.6002.34.36.37.9
      Piperacillin-resistant P aeruginosa4311,2816.0001.94.86.710.9
      Cef3-resistant Enterobacter spp4359419.602.36.010.414.517.7
      Carbapenem-resistant Enterobacter spp3940540.500000.22.5
      Cef3-resistant Klebsiella pneumoniae4516,2601.80000.81.86.0
      Cef3-resistant Escherichia coli4996,2670.60000.20.61.6
      Quinolone-resistant E coli4892,9313.600.21.12.03.07.3
      Penicillin-resistant pneumococci41460716.803.05.910.020.528.6
      Cefotaxime/ceftriaxone-resistant pneumococci3632724.80002.07.526.3
      MRSA, Methicillin-resistant Staphylococcus aureus; CNS, coagulase-negative staphylococci; Cef3, ceftazidime, cefotaxime, or ceftriaxone; Quinolone, ciprofloxacin, ofloxacin, or levofloxacin; Carbapenem, imipenem or meropenem.
      For each antimicrobial agent and pathogen combination, resistance rates were calculated as:Number of resistant isolatesNumber of isolates tested×100
      Table 1, Table 2 from the ICU component update previously published device-associated rates and device utilization (DU) ratios by type of ICU.
      • CDC NNIS System
      National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992 to June 2003, issued August 2003.
      • Jarvis W.R.
      • Edwards J.R.
      • Culver D.H.
      • Hughes J.M.
      • Horan T.
      • Emori T.G.
      • et al.
      Nosocomial infection rates in adult and pediatric intensive care units in the United States.
      As noted above, data from a shorter, more recent time period is presented which differs from previous reports. In general, the device-associated urinary tract and bloodstream infection rates are slightly lower than before. In these tables, the percentile distributions that display the infection rates and DU ratios require data from at least 20 different units. Each of the analyses of ICU data excluded rates or DU ratios for units that did not report at least 50 device-days or patient-days. Because of this, the number of units contributing data in the tables is not exactly the same.
      The number of units reporting data from burn and respiratory ICUs is not adequate to provide distributions of infection rates and DU ratios. The data for combined medical/surgical ICUs are split into 2 groups by type of hospital: “major teaching” and “all others.” Major teaching status is defined as a hospital that is an important part of the teaching program of a medical school and a major unit in the clinical clerkship program. The combined medical/surgical ICUs from major teaching hospitals had significantly higher infection rates and DU ratios than combined medical/surgical ICUs from all of the other hospitals. Teaching affiliation was not an important factor for any other type of ICU.
      For the ICU component, device-days consist of the total number of ventilator-days, central line-days, and urinary catheter-days. The DU of an ICU is one measure of the unit's invasive practices that constitutes an extrinsic risk factor for nosocomial infection.
      • Jarvis W.R.
      • Edwards J.R.
      • Culver D.H.
      • Hughes J.M.
      • Horan T.
      • Emori T.G.
      • et al.
      Nosocomial infection rates in adult and pediatric intensive care units in the United States.
      As such, DU may also serve as a marker for severity of illness of patients in the unit, that is, patients' intrinsic susceptibility to infection.
      Site distributions of infections for coronary care, medical, pediatric, and combined medical-surgical ICUs have been published elsewhere.
      • Richards M.J.
      • Edwards J.R.
      • Culver D.H.
      • Gaynes R.P.
      • the National Nosocomial Infections Surveillance System
      Nosocomial infections in coronary care units in the United States.
      • Richards M.J.
      • Edwards J.R.
      • Culver D.H.
      • Gaynes R.P.
      • the National Nosocomial Infections Surveillance System
      Nosocomial infections in medical intensive care units in the United States.
      • Richards M.J.
      • Edwards J.R.
      • Culver D.H.
      • Gaynes R.P.
      • the National Nosocomial Infections Surveillance System
      Nosocomial infections in pediatric intensive care units in the United States.
      • Richards M.J.
      • Edwards J.R.
      • Culver D.H.
      • Gaynes R.P.
      • the National Nosocomial Infections Surveillance System
      Nosocomial infections in combined medical-surgical intensive care units in the United States.
      Figure 1 shows the rates of antimicrobial resistance among selected pathogens identified from patients in the ICU with nosocomial infections. For each antimicrobial/pathogen pair, the pooled mean rate of resistance for January through December 2003 is displayed. Next to or overlapping this point is the average rate of resistance (±1 SD) over the previous 5-year period (shaded bars). The number of isolates tested from January through December 2003 and the percentage increase in the resistance rate during 2003 compared with the previous 5 years are shown in the 2 columns to the right of the graph. The continuing increase in antimicrobial resistance in U.S. hospitals remains a concern. Of note, the proportion of Staphylococcus aureus isolates that were resistant to methicillin, oxacillin, or nafcillin continues to rise and is nearly 60%, and there has been a nearly 50% increase in nonsusceptible Klebsiella pneumoniae isolates to 3rd generation cephalosporins between 2002 and 2003. However, the rate of increase has diminished for several pathogens, including vancomycin-resistant Enterococcus, which was reported as +31% in 2000 compared to +12% in 2003.
      • CDC NNIS System
      National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992—June 2001, issued August 2001.
      Although these data are limited to patients in ICUs, they are not otherwise risk-adjusted and comparisons of these rates between hospitals should be made with caution.
      Figure thumbnail gr1
      Fig 1Selected antimicrobial-resistant pathogens associated with nosocomial infections in ICU patients, comparison of resistance rates from January through December 2003 with 1998 through 2002, NNIS System. CNS, Coagulase-negative staphylococci; 3rd Ceph, resistance to 3rd generation cephalosporins (either ceftriaxone, cefotaxime, or ceftazidime); Quinolone, resistance to either ciprofoxacin or ofloxacin. Percent (%) increase in resistance rate of current year (January-December 2003) compared with mean rate of resistance over previous 5 years (1998-2002): [(2003 rate – previous 5-year mean rate)/previous 5-year mean rate] × 100. ∗∗“Resistance” for E coli or K pneumoniae is the rate of nonsusceptibility of these organisms to either 3rd Ceph group or aztreonam.
      Table 3, Table 4 from the HRN component update the previously published, device-associated rates and DU ratios in each of 4 birth weight categories.
      • CDC NNIS System
      National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992 to June 2003, issued August 2003.
      • Gaynes R.P.
      • Martone W.J.
      • Culver D.H.
      • Emori T.G.
      • Horan T.C.
      • Banerjee S.N.
      • et al.
      Comparison rates of nosocomial infections in neonatal intensive care units in the United States.
      For the HRN component, device-days consist of the total number of ventilator-days and umbilical catheter- or central line-days. Each of the analyses of HRN data excluded rates or DU ratios for units that did not report at least 50 device-days or patient-days. Because of this, the number of units contributing data in the tables is not exactly the same. As for the ICU component, there were sufficient data to limit the analysis to the period January 2002 through June 2004. Although the percentile distribution of the rates is provided, for most birth-weight categories the number of pneumonias and ventilator-days is still relatively small and the data should be considered provisional. Percent distributions of infections by major site of nosocomial infection and pathogens by major site, and other HRN analyses, have been published.
      • Gaynes R.P.
      • Edwards J.R.
      • Jarvis W.R.
      • Culver D.H.
      • Tolson J.S.
      • Martone W.J.
      • et al.
      Nosocomial infections among neonates in high-risk nurseries in the United States.
      Table 5, Table 6, Table 7, Table 8 from the surgical patient component update previously published rates.
      • CDC NNIS System
      National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992 to June 2003, issued August 2003.
      • Culver D.H.
      • Horan T.C.
      • Gaynes R.P.
      • Martone W.J.
      • Jarvis W.R.
      • Emori T.G.
      • et al.
      Surgical wound infection rates by wound class, operative procedure, and patient risk index.
      Table 5 displays SSI rates by operative procedure and NNIS risk index category. When the SSI rates for adjacent risk categories for a particular operation were not statistically different, they were combined into a single risk category. For example, because the SSI rates for cardiac surgery with 2 or 3 risk factors were similar, the data were combined into a new category 2,3. Thus, the number of risk index categories in the tables will differ depending upon the operation. For small bowel and organ transplant operations, rates for risk categories 2 and 3 are now reported separately. For digestive tract operations, rates for risk categories 0 and 1 are now reported separately. However, for 3 other operations, fewer risk categories are reported, ie, for appendectomy and gastric operations, categories 2 and 3 are combined, and for colon operations, categories M and 0 are combined. Further, the duration cut point for liver/pancreas operations increased from 4 to 5 hours, and for other eye operations, it increased from 2 to 3 hours.
      For a hospital to be represented in Table 6, it must have reported sufficient data, that is, at least 20 operations in a given risk index category for the procedure. Note that the percentile distributions are not available for every operative procedure and risk index category because percentile distributions of the procedure-specific and risk-index-specific rates required sufficient data from at least 20 hospitals.
      Laparoscopes and endoscopes are being used with increasing frequency to perform operations. Table 7 lists 4 operations in which the use of a laparoscope has been incorporated into the SSI risk index. When other risk factors were controlled, cholecystectomy, colon operation, gastric operation, and appendectomy had lower SSI rates when a scope was used. However, there were some differences among these operations. For cholecystectomy and colon operations, the influence of scope use was captured by subtracting 1 from the number of risk factors (ASA score ≥3; duration of operation >75th percentile; or contaminated or dirty wound class) present whenever the procedure was done laparoscopically. “M” indicates minus 1 (−1) in the modified risk category, where no risk factors were present and the procedure was performed with a laparoscope (ie, 0 − 1 = −1). For colon operations, in contrast to the previously published report,
      • CDC NNIS System
      National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992 to June 2003, issued August 2003.
      there is now no significant difference in the rates between risk category M and 0 and so is displayed as a combined M,0 rate in Table 7. For appendectomy and gastric operation, the use of a scope was only important if the patient had no other risk factors. Therefore, we split the index value of 0 risk factors into 0-No and 0-Yes. The percentile distributions of the 4 operative procedures with modified SSI risk index categories have not been developed at this time.
      Table 8 displays SSI rates by specific site after coronary artery bypass graft operations in which incisions are made at both the chest and the donor vessel harvest sites.
      The data in Table 9, Table 10 are from Phase 3 (January 1998 through November 1999) of the Intensive Care Antimicrobial Resistance Epidemiology (ICARE) Project and the NNIS Antimicrobial Use and Resistance (AUR) component (December 1999 through June 2004) and update previously published reports.
      • CDC NNIS System
      National Nosocomial Infections Surveillance (NNIS) system report, data summary from January 1992 to June 2003, issued August 2003.
      • Fridkin S.K.
      • Steward C.D.
      • Edwards J.R.
      • Pryor E.R.
      • McGowan Jr., J.E.
      • Archibald L.K.
      • et al.
      Surveillance of antimicrobial use and antimicrobial resistance in United States hospitals: Project ICARE Phase 2.
      • CDC NNIS System
      Intensive care antimicrobial resistance epidemiology (ICARE) surveillance report, data summary from January 1996 through December 1997.
      For the purpose of analysis, grams of antimicrobial agents were converted into number of defined daily doses used each month in each hospital area. A defined daily dose is the average daily dose in grams of a specific antimicrobial agent given to an average adult patient (Appendix A).
      • Amsden G.W.
      • Schentag J.J.
      Tables of antimicrobial agent pharmacology.

      WHO Collaborating Centre for Drug Statistics Methodology. 2004. Anatomical Therapeutic Chemical (ATC) classification index with defined daily doses (DDD). Available from: http://www.whocc.no/atcddd/.

      Note that unless otherwise indicated, we used the 2004 WHO DDD values,

      WHO Collaborating Centre for Drug Statistics Methodology. 2004. Anatomical Therapeutic Chemical (ATC) classification index with defined daily doses (DDD). Available from: http://www.whocc.no/atcddd/.

      which is different from previous reports. Table 9 shows use of selected oral and parenteral antimicrobial agents in defined daily doses. Antimicrobial use was stratified by route of administration and hospital area. Because outpatient antimicrobial use could not be estimated reliably from hospital pharmacy records, data on outpatient antimicrobial use were not collected. Antimicrobial agents with similar spectrum or clinical indications were grouped and shown in Appendix A. On the basis of detailed analysis, antimicrobial usage rates were found to vary by type of ICU, so usage rates and percentiles are shown for each type of ICU for which there were at least 20 units reporting data. The number of burn and respiratory ICUs reporting usage data is insufficient to include in the table. The number of neurosurgical and pediatric ICUs and hematology/oncology/transplant wards is insufficient to provide percentile distributions; only pooled mean usage rates are displayed. Table 10 shows ICARE/AUR resistance data for selected antimicrobial-resistant bacteria on the basis of reported antimicrobial susceptibility test results on all non-duplicate clinical isolates processed by the laboratory during each study month. A duplicate isolate was defined as an isolate of the same species of bacteria with the same antimicrobial susceptibility pattern in the same patient in the same month, regardless of the site of isolation. All isolates, whether responsible for hospital-acquired or community-acquired infection or for colonization, were reported to ICARE/AUR by participating hospitals. Hospitals used National Committee for Clinical Laboratory Standards interpretive standards for minimum inhibitory concentration, or zone diameter testing standards to report numbers of susceptible, intermediate, or resistant organisms. A minimum of 10 isolates must be tested in a hospital area for resistance rates to be calculated for that area. Resistance data have been combined for all ICU types because detailed analysis demonstrated that, in general, resistance rates (percent prevalence) did not differ by type of ICU. Also, these data show that for most antimicrobial-resistant bacteria, resistance rates are highest in the ICU areas, followed by non-ICU inpatient areas, with lowest rates in the outpatient areas.
      If you would like to compare your hospital's rates and ratios with those in this report, you must first collect information from your hospital in accordance with the methods described for the NNIS System.
      • Emori T.G.
      • Culver D.H.
      • Horan T.C.
      • Jarvis W.R.
      • White J.W.
      • Olson D.R.
      • et al.
      National nosocomial infections surveillance (NNIS) system: description of surveillance methodology.
      • Horan T.C.
      • Gaynes R.P.
      Surveillance of nosocomial infections.
      • Horan T.C.
      • Emori T.G.
      Definitions of key terms used in the NNIS system.
      You should also refer to Appendices B and C for further instructions. Appendix B discusses the calculation of infection rates and DU ratios for the ICU or HRN surveillance components. Appendix C gives a step-by-step method for interpretation of percentiles of infection rates or DU ratios. A high rate or ratio (>90th percentile) does not necessarily define a problem; it only suggests an area for further investigation. Similarly, a low rate or ratio (<10th percentile) may be the result of inadequate infection detection.
      Hospitals should use these data to guide local improvement efforts aimed at reducing infection rates as much as possible.

      Appendix A. Defined daily dose (DDD) of antimicrobial agents, by class and group

      Tabled 1
      ClassGroupAntimicrobial AgentDDD
      β-lactamsPenicillin groupPenicillin G1.2 × 106 U
      Procaine Penicillin G2.4 × 106 U
      Penicillin G benzathine1.2 × 106 U
      Penicillin V1g
      Ampicillin groupAmpicillin (parenteral)2g
      Ampicillin (oral)2g
      Ampicillin/sulbactam2g
      Amoxicillin (oral)1g
      Amoxicillin/Clavulanic Acid (oral)1g
      Antistaphylococcal penicillins (Methicillin group)Nafcillin4g
      Oxacillin2g
      Dicloxacillin (oral)2g
      Antipseudomonal penicillinsPiperacillin14g
      Piperacillin/Tazobactam14g
      Ticarcillin15g
      Ticarcillin/Clavulanic Acid15g
      First-generation cephalosporinsCefazolin3g
      Cephalothin4g
      Cefadroxil (oral)2g
      Cephalexin (oral)2g
      Second-generation cephalosporinsCefotetan4g
      Cefmetazole4g
      Cefoxitin6g
      Cefuroxime3g
      Cefuroxime axetil (oral)1g
      Cefaclor (oral)1g
      Cefprozil (oral)1g
      Third-generation cephalosporinsCefotaxime4g
      Ceftazidime4g
      Ceftizoxime4g
      Ceftriaxone2g
      Cefixime (oral)0.4g
      Cefipime2g
      CarbapenemsMeropenem2g
      Imipenem cilastatin2g
      Other β -lactamsAztreonam4g
      GlycopeptidesVancomycin (parenteral)2g
      Vancomycin (oral)1g
      FluoroquinolonesCiprofloxacin (parenteral)0.5g
      Ciprofloxacin (oral)1g
      Ofloxacin (parenteral)0.4g
      Ofloxacin (oral)0.4g
      Levofloxacin (parenteral)0.5g
      Levofloxacin (oral)0.5g
      Trovafloxacin (parenteral)0.2g
      Trovafloxacin (oral)0.2g
      Sparfloxacin (oral)0.2g
      Norfloxacin (oral)0.8g
      Lomefloxacin0.4g
      Trimethoprim/SulfamethoxazoleTrimethoprim component (oral)0.4g
      Trimethoprim compound (parenteral)0.4g
      DDD for those agents marked with an asterisk () are adapted from Amsden GW, Schentag JJ. Tables of antimicrobial agent pharmacology. In: Mandell GL, Bennett JE, Dolin R, editors. Principles and practice of infectious diseases. 4th ed. New York: Churchill Livingstone; 1995. p. 492-528. All other DDD are from: WHO Collaborating Centre for Drug Statistics Methodology. Anatomical Therapeutic Chemical (ATC) classification index with defined daily doses (DDD). 2004. Available from: http://www.whocc.no/atcddd/.

      Appendix B

      How to calculate a device-associated infection rate and device utilization ratio with ICU and HRN component data

        Calculation of device-associated infection rate

      • Step 1:
        Decide on the time period for your analysis. It may be a month, a quarter, 6 months, a year, or some other period.
      • Step 2:
        Select the patient population for analysis, ie, the type of ICU or a birthweight category in the HRN.
      • Step 3:
        Select the infections to be used in the numerator. They must be site-specific and must have occurred in the selected patient population. Their date of onset must be during the selected time period.
      • Step 4:
        Determine the number of device-days which is used as the denominator of the rate. Device-days are the total number of days of exposure to the device (central line, ventilator, or urinary catheter) by all of the patients in the selected population during the selected time period.
        Example: Five patients on the first day of the month had one or more central lines in place: 5 on day 2; 2 on day 3; 5 on day 4; 3 on day 5; 4 on day 6; and 4 on day 7. Adding the number of patients with central lines on days 1 through 7, we would have 5 + 5 + 2 + 5 + 3 + 4 + 4 = 28 central line-days for the first week. If we continued for the entire month, the number of central line-days for the month is simply the sum of the daily counts.
      • Step 5:
        Calculate the device-associated infection rate (per 1000 device-days) using the following formula:
        Device-associated infection rate=Number of device-associated infections for a specific siteNumber of device-days×1000


        Example:
        Central line-associated bloodstream infection rate=Number of central line-associated bloodstream infectionsNumber of central line-days×1000


        Calculation of DU ratio

      • Steps 1,2,4:
        Same as that for device-associated infection rates, plus determine the number of patient-days which is used as the denominator of the DU ratio. Patient-days are the total number of days that patients are in the ICU (or HRN) during the selected time period.
        Example: Ten patients were in the unit on the first day of the month; 12 on day 2; 11 on day 3; 13 on day 4; 10 on day 5; 6 on day 6; and 10 on day 7; and so on. If we counted the patients in the unit from days 1 through 7, we would add 10 + 12 + 11 + 13 + 10 + 6 + 10 for a total of 72 patient-days for the first week of the month. If we continued for the entire month, the number of patient-days for the month is simply the sum of the daily counts.
      • Step 5:
        Calculate the DU ratio with the following formula:
        DU ratio=Number of device-daysNumber of patient-days


        With the number of device-days and patient-days from the examples above, DU = 28/72 = 0.39 or 39% of patient-days were also central line-days for the first week of the month.
      • Step 6:
        Examine the size of the denominator for your hospital's rate or ratio. Rates or ratios may not be good estimates of the true rate or ratio for your hospital if the denominator is small, ie, <50 device-days or patient-days.
      • Step 7:
        Compare your hospital's ICU/HRN rates or ratios with those found in the tables of this report. Refer to Appendix C for interpretation of the percentiles of the rates/ratios.

      Appendix C

      Interpretation of percentiles of infection rates or device utilization ratios

      • Step 1:
        Evaluate the rate (ratio) you have calculated for your hospital and confirm that the variables in the rate (both numerator and denominator) are identical to the rates (ratios) in the table.
      • Step 2:
        Examine the percentiles in each of the tables and look for the 50th percentile (or median). At the 50th percentile, 50% of the hospitals have lower rates (ratios) than the median and 50% have higher rates (ratios).
      • Step 3:
        Determine if your hospital's rate (ratio) is above or below this median.

        Determining whether your hospital's rate or ratio is a HIGH outlier

      • Step 4:
        If it is above the median, determine whether the rate (ratio) is above the 75th percentile. At the 75th percentile, 75% of the hospitals had lower rates (ratios) and 25% of the hospital had higher rates (ratios).
      • Step 5:
        If the rate (ratio) is above the 75th percentile, determine whether it is above the 90th percentile. If it is, then the rate (ratio) is a high outlier which may indicate a problem.

        Determining whether your hospital's rate or ratio is a LOW outlier

      • Step 6:
        If it is below the median, determine whether the rate (ratio) is below the 25th percentile. At the 25th percentile, 25% of the hospitals had lower rates (ratios) and 75% of the hospitals had higher rates (ratios).
      • Step 7:
        If the rate (ratio) is below the 25th percentile, determine whether it is below the 10th percentile. If the rate is, then it is a low outlier which may be due to underreporting of infections. If the ratio is below the 10th percentile, it is a low outlier and may be a result of infrequent DU, short duration of DU, or both.
      • Note:
        Device-associated infection rates and device utilization ratios should be examined together so that preventive measures may be appropriately targeted. For example, you find that the ventilator-associated pneumonia rate for a certain type of ICU is consistently above the 90th percentile and the ventilator utilization ratio is routinely between the 75th and 90th percentile. Since the ventilator is a significant risk factor for pneumonia, you may want to target your efforts on reducing the use of ventilators or limiting the duration with which they are used on patients in order to lower the ventilator-associated pneumonia rate in the unit.

      Appendix D

      CDC NNIS PERSONNEL

      Denise Cardo, MD
      Director, Division of Healthcare Quality Promotion (DHQP), National Center for Infectious Diseases
      Teresa Horan, MPH
      NNIS Coordinator, Healthcare Outcomes Branch (HOB), DHQP
      Mary Andrus, BA, RN, CIC
      Nurse Epidemiologist, HOB
      Margaret Dembinski, BS
      MPH Student, HOB
      Jonathan Edwards, MS
      Mathematical Statistician, HOB
      Gloria Peavy
      Computer Technical Support, HOB
      James Tolson, BS
      Information Technology Specialist, HOB
      Debra Wagner, BA
      MPH Student, HOB

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      1. WHO Collaborating Centre for Drug Statistics Methodology. 2004. Anatomical Therapeutic Chemical (ATC) classification index with defined daily doses (DDD). Available from: http://www.whocc.no/atcddd/.