Reservoirs of Nosocomial Pathogens at a University Teaching Hospital In Nigeria

Abstract

Two hundred and seventy seven microorganisms were isolated between February and August 1998 from surgical and medical wards including the haemodialysis unit and microbiology laboratory of a University Teaching Hospital in Lagos, Nigeria. Environmental Contamination was high. Medical and surgical wards accounted for the highest contamination rates of 67% and 63% respectively; followed by the microbiology laboratory, 48% and the Haemodialysis unit, 30%. Within the wards, the areas most contaminated were the sinks, bedpans, wastebins, mattresses and toilet seats, Staphylococcus aureus was the most commonly isolated organism with a prevalence rate of 39.3% closely followed by Klebsiella pneumoniae, 24.6%. Others were coagulase-negative Staphylococci, 13.7%; Escherichia coli, 8.3% Pseudomonas aeruginosa, 9.0%, Proteus mirabilis, 1.8%; Citrobacter freundii, 1.1%; Proteus vulgaris, 0%; Salmonella paratyphi A, 0.7%; Enterobacter aerogenes, 0.4% and Salmonella typhi, 0.4%. Antibiograms of the isolates suggested three clusters of Staphylococcus aureus, groups SA1, SA2 and SA3. The largest group SA!, present in the Medical wards, Surgical wards, Microbiology laboratory and the haemodialysis unit, was Methicillin-sensitive. SA2 was present in only the medical and surgical wards while SA3 was only found in the surgical wards. Two clusters each, KP1 and KP2 of Klebsiella pneumoniae and EC1 and EC2 of Escherichia coli were obtained while there was only one cluster, PA1, of Pseudomonas aeruginosa. KP1, EC1 and PA1 were found in all the wards. Lack of adequate running water and poor environmental sanitation were major contributory factors to the high contamination rates.


[J. of the Nig. Infection Control Assn. Vol.3(2) 2000: 18-24]