COMPARATIVE SENSITIVITY OF 13 SPECIES OF PATHOGENIC BACTERIA TO 7 CHEMICAL GERMICIDES

Background: The relative resistance of diverse human bacterial pathoge ns to commonly used germicidal agents has not been established. Method s: We measured by titration the survival of thirteen different bacteri a after exposure to glutaraldehyde, formaldehyde, hydrogen peroxide, p eracetic acid, cupric ascorbate, sodium um hypochlorite, or phenol. Re sults: Our comparative experiments allowed classification of the organ isms' survival into four groups: (a) Pseudomonas aeruginosa and Staphy lococcus aureus showed the most resistance, (b) Clostridium perfringen s, Salmonella typhimurium, Staphylococcus epidermidis, and Escherichia coli O157:H7 showed intermediate resistance, (c) Listeria monocytogen es, Shigella sonnei, and Vibrio parahaemolyticus survived some treatme nts with chemical agents only in the presence of protecting protein (s erum albumin), and (d) Vibrio cholerae, Vibrio vulnificus, Bacillus ce reus, and Yersinia enterocolitica did not survive any of the treatment s applied. Conclusion: We found species that more frequently survived exposure to germicidal agents were also those most commonly reported i n association with hospital infections. Our findings suggest that resi stance to disinfectants may be more important than pathogenicity in de termining the relative prominence of an organism as an agent responsib le for nosocomial infections.