Disinfectant and antibiotic activities: A comparative analysis in Brazilian hospital bacterial isolates

Nosocomial infections are an important cause of morbidity and mortality all over the world. It has been shown that appropriate environmental hygienic and disinfection practices can be very helpful to hospital infection contro l. The purpose of this study was to evaluate the bactericidal activity of s ome disinfectants against antibiotic-susceptible and antibiotic-resistant h ospital bacterial isolates. The susceptibility of 27 clinical isolates to d isinfectants and antibiotics was determined by the Association of Official Analytical Chemist's (AOAC) Use-Dilution method and by the Kirby-Bauer meth od, respectively. All strains tested were susceptible to sodium hypochlorit e, glutaraldehyde and to the association quaternary ammonium formaldehyde - ethyl alcohol disinfectants. However, the susceptibility of strains to phe nol and to one quaternary ammonium compound was variable. Among twenty-one antibiotic-multiresistant strains (methicillin-resistant staphylococci, Ent erococcus spp, Pseudomonas aeruginosa, Klebsiella pneumoniae, Proteus mirab ilis, Enterobacter cloacae, Serratia marcescens and Escherichia coli) eleve n (52%) and eight (38%) strains were resistant to the quaternary ammonium a nd phenol compounds, respectively. Among six isolates that demonstrated sus ceptibility to antibiotics (staphylococci, Enterococcus spp, P. mirabilis, E. cloacae and E. coli) two strains (33 %) showed resistance to these disin fectants. The results demonstrated the lack of correlation between antibiot ic-susceptibility and susceptibility to disinfectants in hospital strains.