Review of disinfectant susceptibility of bacteria isolated in hospital to commonly used disinfectants

Abstract

The susceptibility of clinical isolates and indigenous bacteria to commonly used disinfectants was investigated during different time periods. Among the clinical isolates tested during Period I (August 1985-July 1986, 6 genera, 9 species, 353 strains) there were many resistant strains not killed within a short period of time by the recommended concentration of chlorhexidine gluconate (CHG) or benzalkonium chloride (BAC). During Period II (October 1987-May 1988, 6 genera, 9 species, 152 strains), however, a reduction in the number of strains resistant to these disinfectants was observed. The use of the broad spectrum disinfectant povidone-iodine (PVP-I) increased between those two time periods. With regard to the susceptibility of indigenous bacteria, tests were carried out on bacteria isolated from sinks and physicians' hands in the gastroenterology division of the Departments of Internal Medicine and Surgery at the hospital. During Phase I (April-June 1987), strains of Pseudomonas and Serratia resistant to CHG and BAC were isolated from sinks, while the same strains of Serratia were also isolated from physicians' hands. During Phase II (March-May 1988), however, no resistant strains were isolated. A comparison of the consumption of disinfectants during the two phases revealed that a greater amount of CHG was consumed during Phase I, while a greater amount of PVP-I was consumed during Phase II. There was a strong indication, therefore, that bacteria resistant to CHG and BAC decrease with the increased use of PVP-I.