Evaluation of bacterial contaminants found on unused paper towels and possible postcontamination after handwashing: A pilot study

Background

Bacterial contamination is a concern in the pulp and paper industry. Not only is the machinery contaminated but also can be the end-paper products. Bacterial transmission from unused paper towels to hands and surfaces is not well documented.

Methods

The culturable bacterial community of 6 different unused paper towel brands was determined by culture methods and by sequencing the 16S ribosomal DNA of bacterial contaminants. Next, we investigated the possible airborne and direct contact transmissions of these bacterial contaminants during hand drying after washing.

Results

Between 10² and 10⁵ colony-forming units per gram of unused paper towels were isolated from the different paper towel brands. Bacteria belonging to the Bacillus genus were by far the most abundant microorganisms found (83.0%), followed by Paenibacillus (15.6%), Exiguobacterium (1.6%), and Clostridium (0.01%). Paper towels made from recycled fibers harbored between 100- to 1,000-fold more bacteria than the virgin wood pulp brand. Bacteria were easily transferred to disposable nitrile gloves when drying hands with paper towels. However, no evidence of bacterial airborne transmission was observed during paper towel dispensing.

Conclusion

This pilot study demonstrated that a large community of culturable bacteria, including toxin producers, can be isolated from unused paper towels and that they may be transferred to individuals after handwashing. This may have implications in some industrial and clinical settings as well as in immunocompromised individuals.

Key Words: Hand hygiene, Bacillus, 16s rRNA, Spores