Assessment of antibiotics susceptibility profiles of some selected clinical isolates from laboratories in Nigeria

Abstract

Because antimicrobial resistance patterns are continually evolving and multi-drug resistant (MDR) organisms undergo progressive antimicrobial resistance, continuously updated data on antimicrobial susceptibility profiles will continue to be essential to ensure the provision of safe and effective empiric therapies. This current study reports on the assessment of antibiotics susceptibility profiles of some selected clinical isolates from laboratories in Nigeria. Thirteen antibiotics were bought from different pharmacy shops in Calabar metropolis and their susceptibility profiles were evaluated against some clinical isolates obtained from Microbiology Section of Sufat Medical Laboratories, Ishie, Calabar; Microbiology laboratory Unit of University of Calabar Teaching Hospital, Calabar and Department of Microbiology, University of Calabar, Calabar. These included Escherichia coli,Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus andStreptococcus pyogenes. The species level identification was then carried out by standard biochemical test and by comparing their characteristics with those of known taxa. Susceptibility tests were performed by Bauer-Kirby disc diffusion by using Muller Hinton Agar (CM337-Oxoid). The results were expressed as susceptible/resistant according to criteria developed by NCCLS. S. aureus was susceptible to 09 (75.0%) and resistant to 3 (25.0%) of 12 antibiotics used. Str. pyogenes was susceptible to 8 (66.7%) antibiotics and resistant to 4 (33.3%). Of 11 antibiotics tested against E. coli and P. aeruginosa, E. coli was susceptible to 10 (90.9%) and resistant to 1 (09.1%). P. aeruginosa was susceptible to 9 (81.8%) and resistant to 2 (18.2%). Of 13 antibiotics tested against K. pnenmoniae, it was susceptible to 10(83.3%) and resistant to 2(16.7%). Resistance to chloramphenicol was common to all isolates except K. pneumoniae. Erythromycin-resistance was common to Str. pyogenes. Also, rifampicin-resistance was common to S. aureus. Resistance to gentamicin and tetracycline was only common to Str. pyogenes while penicillin-resistance was common to S. aureus only. Though, some multi-drug resistant organisms were reported in this study, some organisms were highly susceptible to most of the test antibiotics. There are several limitations of this work. Nevertheless, the results can serve to direct any national effort aimed toward reducing the antimicrobial resistance problems of local hospitals. The reasons for the differences in antimicrobial drug–resistant patterns might be related to infection control practices or to timing of the introduction of resistant organisms. However, more research is needed to clarify these differences. We believe that our findings represent the endemic multi-drug resistant situation in our hospitals in Nigeria. Key words: Antibiotics, assessment, clinical isolates, resistance pattern, susceptibility profiles