Evaluation of hospital disinfection as a means of controlling endemic nosocomial pathogens in a University Teaching Hospital in Nigeria
Evaluation of hospital environment disinfection as a means of controlling endemic nosocomial pathogens in a University Teaching Hospital in Nigeria was evaluated. Disinfectant used in the Hospital was collected from the Infection Control unit and prepared in different concentrations. The isolated bacterial species from the hospital environment were exposed to graded concentrations of the disinfectants and the most effective concentration on each isolate was noted. This procedure was carried out in two successive years (2006 and 2007). Killing rate of the isolates that were resistant to the disinfectants was also carried out and likely effective exposure time was determined. The following bacterial species were isolated: Staphylococcus epidermidis, Klebsiella Pneumoniae, Klebsiella spp., Bacillus subtilis, Enterobacter spp., Serratia marcescens, Pseudomonas aeruginosa, Pseudomonas spp., Escherichia coli, Serratia spp., Bacillus cereus, Citrobacter freundii, Proteus mirabilis, Staphylococcus aureus, Bacillus megaterium, Streptococcus pyogenes, and Streptococcus spp. Minimum Effective Dilution (MED) of the disinfectant on all isolates ranged from 1:300 to1:1000. Staphylococcus aureus and Pseudomonas aeruginosa were the most resistant isolate with MED of 1:400 and 1:300 respectively. Result of killing rate on the two most resistant isolates showed that Staphylococcus aureus and Pseudomonas aeruginosa required 80 and 120 minutes of exposure respectively to the disinfectant to bring about almost total killing of these resistant isolates. The results show that improper disinfections, degradation of disinfectant and lack of routine standardization of disinfectants are responsible for failure of chemical disinfection as a means of controlling nosocomial infections in the hospital.
Keywords: Nosocomial pathogens; Hospital disinfections; Disinfectants and pathogens resistance.