Prevalence and Antimicrobial Susceptibility Profile of Bacteria Isolated from the Environment of two Tertiary Hospitals in Calabar Metropolis, Nigeria

Objective: The objective of this study was to determine the susceptibility pattern of the bacterial isolates obtained from the environment of two hospitals (General hospital – GH and infectious disease hospital – IDH).

Methods: A total of 240 swabs and air samples were collected from two hospitals with 20 samples each from wards, pharmacies, blood banks, theatres, laboratories and intensive care units. Bacterial isolates were obtained from these samples using standard microbiological techniques. Identified isolates were then subjected to antimicrobial sensitivity, minimum inhibitory and bactericidal concentrations determination. The antibiotics used in this study were gentamycin, ofloxacin, norfloxacin, ceporex, ciprofloxacin, reflacine, ampicillin,levofloxacin, ampicillin+cloxacillin, amoxicillin, erythromycin, amoxicillin+clavulanic acid, streptomycin, sulfamethoxazole+ trimethoprim, nalidixic acid, chloramphenicol, cefoxitin and ceftazidime. Mean counts were analysed using student t-test and simple descriptive statistics.

Results: A total mean count of 2940cfu was recorded from both hospitals of which 1949cfu and 991cfu were obtained from GH and IDH, respectively. A comparism of the mean counts for both hospitals unit by unit showed that pharmacy unit alone was significant (p =0.01). A total of 130 bacteria isolates were recovered in this study of which 80(61.5%) and 50(38.5%) were isolated from GH and IDH, respectively. In GH, the lowest MIC and MBC of 470 and 230mg/ml was recorded by P. aeruginosa, S. aureus and Proteus species against ciprofloxacin while other isolates exhibited moderate resistance to this antibiotic. In IDH, the lowest MIC and MBC were recorded by P. aeruginosa, C. freundii, K. pneumoniae and S. marcesens against ampicillin while lowest MIC and MBC was recorded by S. aureus against cefoxitin.

Conclusion: The findings in this study reveal that airborne sources and inanimate surfaces of hospitals are an important reservoir of multidrug resistant nosocomial pathogens.