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Biological verification of sterilization cycles in dental clinics in Mexico

Published:February 15, 2016DOI:https://doi.org/10.1016/j.ajic.2015.09.035
      To the Editor:
      We read with great interest the recent report by Patiño-Marín et al
      • Patiño-Marín N.
      • Martínez-Castañón G.A.
      • Zavala-Alonso N.V.
      • Medina-Solís C.E.
      • Torres-Méndez F.
      • Cepeda-Argüelles O.
      Biologic monitoring and causes of failure in cycles of sterilization in dental care offices in Mexico.
      on the biological verification of sterilization cycles (BVSC) in San Luis Potosí, Mexico. We agree that BVSC is important as a routine component of infection prevention and control.
      As the authors point out, in 2002 we reported failures in 242 of 3,277 tests (7.4%), with convection dry heat failing with greater frequency (10.2%).
      • Acosta-Gío A.E.
      • Mata-Portuguez V.H.
      • Herrero-Farías A.
      • Sánchez Pérez L.
      Biologic monitoring of dental office sterilizers in Mexico.
      Over 19 years, we received tests from 113 dental clinics nationwide, with most participant dentists in Mexico City. Participant dental clinics used 129 different devices (97 autoclaves, 28 convection dry-heat ovens, 3 chemical vapor, and 1 rapid dry-heat). Of 7383 cycles—with in-use dental instrument loads—we detected 753 sterilization failures (10.2%) (Table 1). For the autoclaves, the observed failures were less than expected. No inferences can be made on any type of sterilization equipment because of the diversity of brands and models used as well as rotation of personnel charged with operating the equipment.
      Table 1Instrument sterilization cycles tested and failures detected
      Sterilization techniqueTestsFailuresP value
      P value based on χ2 test.
      95% Confidence interval
      n%n%
      Autoclave6,47687.76439.9.850.83-0.88
      Dry-heat oven5227.16612.6.090.07-0.11
      Chemical steam2122.93516.5.050.03-0.06
      Rapid dry-heat1732.395.2.010.01-0.02
      Total7,3831007531.2.0010.09-0.11
      * P value based on χ2 test.
      It is noteworthy that in the study by Patiño-Marín et al,
      • Patiño-Marín N.
      • Martínez-Castañón G.A.
      • Zavala-Alonso N.V.
      • Medina-Solís C.E.
      • Torres-Méndez F.
      • Cepeda-Argüelles O.
      Biologic monitoring and causes of failure in cycles of sterilization in dental care offices in Mexico.
      participants' responses to a questionnaire reveal autoclave misuse: “140°C, 31 minutes, 19 psi.” Apparently, many dentists among the participants ignore appropriate cycle parameters and fail to read the equipment's thermometer and pressure indicator dial. In general, autoclaves, calibrated at sea level, work at 132°C-134°C and 2 kg/cm2 (274°F and 30 lb/in2) or 121°C and 1 kg/cm2 (250°F and 15 lb/in2). Because of diversity in autoclave design and performance, the manufacturer's written instructions must always be followed for each particular model and load configuration.
      The mandatory use of BVSC remains unknown to most dentists in Mexico. We agree with Patiño-Marín et al
      • Patiño-Marín N.
      • Martínez-Castañón G.A.
      • Zavala-Alonso N.V.
      • Medina-Solís C.E.
      • Torres-Méndez F.
      • Cepeda-Argüelles O.
      Biologic monitoring and causes of failure in cycles of sterilization in dental care offices in Mexico.
      that there is a need to disseminate information on infection control. Health authorities, schools of dentistry, professional associations, and industry must support education efforts to help improve patient safety in dental clinics in Mexico.

      Acknowledgment

      Over 19 years, Carolina Abeytia, Alfredo Aguirre, Jesús Apodaca, Giovanna Carpio, Marycel Gutiérrez, Rocío Gutiérrez, and Alan Osegueda kept the database updated.

      References

        • Patiño-Marín N.
        • Martínez-Castañón G.A.
        • Zavala-Alonso N.V.
        • Medina-Solís C.E.
        • Torres-Méndez F.
        • Cepeda-Argüelles O.
        Biologic monitoring and causes of failure in cycles of sterilization in dental care offices in Mexico.
        Am J Infect Control. 2015; 10: 1092-1095
        • Acosta-Gío A.E.
        • Mata-Portuguez V.H.
        • Herrero-Farías A.
        • Sánchez Pérez L.
        Biologic monitoring of dental office sterilizers in Mexico.
        Am J Infect Control. 2002; 30: 153-157