Distribution and antibiotic susceptibility pattern of methicillin-resistant <i>Staphylococcus aureus</i> isolates in a university Teaching hospital in Nigeria.

Abstract

Background: The rise of methicillin resistant Staphylococcus aureus (MRSA) infection has become a serious health issue. The emergence of mutidrug – resistant MRSA strains compounds chemotherapy and has raised public health concern. In this preliminary study, the distribution and antimicrobial susceptibility profile of MRSA to 10 commonly used antimicrobial agents at the University of Calabar Teaching Hospital (UCTH), Nigeria were determined between June 2005 and May 2006.
Methods: S. aureus were cultured from various clinical samples using standard bacteriologic technique. Methicillin disc diffusion method for the detection of methicillin resistance and Kirby – Bauer NCCLS modified disc diffusion for antibiotic susceptibility tests were used.
Results: The MRSA prevalence rate was 37.5% (33/88) of all S. aureus isolates. Majority of the MRSA strains (15/33) were recovered from blood samples followed by isolates from wound exudates (11/33) and were statistically significant (p<0.05). The rate of MRSA recovery was highest in patients aged 0 – 9 years (63%) and those aged > 50 years (60%) and were statistically significant (r = - 0.083). The MRSA isolates were resistant to penicillin and ampicillin (97.0%), tetracycline (93.9%), Cotrimoxazole (90.9%), Chloramphenicol (78.8%), Cefuroxime (66.7%), Erthromycin (60.6%) and Gentamycin (54.5%). Amoxycillin clavunanic acid and ciprofloxacin were most active with MRSA isolates showing 97% and 93.9% susceptibility to the two drugs respectively. Eighteen (54.5%) MRSA isolates showed resistance to more than four antibiotic groups. One strain was resistant to all of the antimicrobial agents used.
Conclusion: The study affirms the increasing prevalence of multidrug resistant MRSA in Nigeria. There is need for rational chemotherapy, routine detection and regular surveillance of MRSA to limit its spread.


Keywords:incidence, MRSA, multidrug, resistance, chemotherapy; surveillance

Sahel Medical Journal Vol. 11 (4) 2008: pp. 142-147