Prevalence and Antibiotic Susceptibility Patterns of Methicillin-Resistant Staphylococcus Aureus (MRSA) Isolated from Some Communities and Hospitals in Nsukka, Nigeria

Abstract

Methicillin-resistant Staphylococcus aureus (MRSA) is a human pathogen that has emerged as a serious public health problem both in hospital and community settings. This study was conducted to determine the prevalence and antimicrobial resistance patterns of MRSA from healthcare and community environments. A total of 900 samples comprising 600 hospital and 300 community samples were examined. S. aureus was isolated and identified from hospital and community samples using standard laboratory procedures and MRSA strains were identified using Kirby Bauer disk diffusion method. A total of 505 (56.1%) isolates of Staphylococcus aureus were recovered out of which 295 (32.8%) were MRSA. Generally, among the hospital samples, S. aureus was recovered from 367 (61.2%) samples out of which 209 (56.9%) were MRSA while among the community samples, S. aureus was recovered from 150 (50%) samples, out of which 86 (28.7%) were MRSA.  From individual hospitals, MRSA had prevalence between 30.0% and 50.0% but the differences were not significant (p˃0.05). Similarly, the differences in prevalence among different sample types (urine, wound, swabs etc.) were not significant (p˃0.05). In the five communities sampled, MRSA had prevalence values between 26.7% and 30.9% but again no significant differences were apparent. The MRSA isolates exhibited a high rate of resistance to most of the antibiotics tested. Most of the isolates were resistant to at least one antibiotic and 190 isolates (64.4%) were resistant to four or more antibiotics. The most resisted antibiotics for hospital samples were amoxicillin (88.5%); pefloxacin (70.8%); cotrimoxazole (62.2%); penicillin G (59.3%) and oxacillin (64.6%) while the least resisted were erythromycin (31.1%); ciprofloxacin (42.1%); gentamycin (46.9%); cefuroxine (45%) and streptomycin (37.3%). For the community isolates, the most resisted were penicillin G (65.1%); oxacillin (74.4%); and ceftriaxone (75.6%) while the least resisted were cotrimoxazole (40%); ciprofloxacin (31.4%) and amoxicillin (26.7%). The E test for the detection of minimum inhibitory concentration (MIC) ranged from 0.75 µg/ml to 8 µg/ml. This study showed that there is high prevalence of MRSA in Nsukka, that the MRSA strains have developed resistance to other classes of antibiotics in addition to β-lactams.