Susceptibility of Antibiotic-susceptible and Antibiotic-resistant Hospital Bacteria to Disinfectants

Objective: To evaluate whether hospital strains of antibiotic-resistant bacteria exhibited altered susceptibility to disinfectants.

Design: Antibiotic-susceptible bacteria were obtained from American Type Culture Collection: Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Salmonella choleraesuis, and Pseudomonas aeruginosa. Hospital strains of antibiotic-resistant bacteria were obtained from clinical isolates, including: S aureus, S epidermidis, E coli, Enterococcus species, K pneumoniae, and P aeruginosa. The Association of Official Analytical Chemist's use-dilution method was used to test these 12 strains of 7 bacterial pathogens for their susceptibility to a phenol and a quaternary ammonium compound. For five pathogens, we tested a susceptible and a more resistant strain in 20 comparative trials (5 pathogens, 2 disinfectants, 2 dilutions per disinfectant).

Results: In our 20 comparative trials, the antibiotic-resistant strains exhibited an increased resistance to the disinfectant in only a single instance.

Conclusions: Our data demonstrate that the development of antibiotic resistance does not appear to be correlated to increased resistance to disinfectants.