ABSTRACT
Methicillin-resistant Staphylococcus aureus (MRSA) is among the currently ravaging human pathogens responsible for most of health-care associated and community acquired infections around the world. The aim of this study was to determine the antibiotic profiles and prevalence of MRSA isolates among healthy undergraduate students. A total of 300 urine, stool and nasal swab samples from various anatomical sites of the study participants were cultured on mannitol salt agar and identified as S. aureus using catalase, coagulase and DNAse tests.
Antibiotic susceptibility determination was performed using the disk diffusion susceptibility method whilst MRSA were identified by cefoxitin disk diffusion method as per CLSI guidelines. Beta lactamase production was carried out by combination of the acidimetric and iodometric tube methods. The result obtained showed the presence of S. aureus with 41.3% prevalence. The distribution of the isolates was as follows: 65 isolates (43.3%) from urine, 17 (34.0%) from stool and 42 (42.0%) from nasal swab. There was however no association between prevalence and sample type (p value=0.74).
In the assessment of drug susceptibility profile for S. aureus isolates, it was observed that 30.8% of the isolates from urine samples were resistant to gentamicin, 52.9% of the isolates from stool also resistant to gentamicin whilst S. aureus isolates from nasal swab exhibited 14.3% resistance to gentamicin. All the S. aureus isolates showed 100% resistance to augmentin and ceftazidime. Out of the 124 S. aureus isolates recovered, a total of 45 (36.3%) were MRSA. However, there was no association between prevalence and sample type (p value=0.82). Majority of the MRSA isolates were susceptible to gentamicin, and ofloxacin while highest resistance was recorded for augmentin and ceftazidime. Among the 124 S. aureus isolates, a total of 94, (75.8 %) were beta lactamase producers.
This study has demonstrated high prevalence of MRSA isolates from apparently healthy individuals and underlines the need for periodic surveillance studies of this type.
KEYWORDS: Antimicrobial resistance, MRSA, Antibiotic susceptibility profile, Staphylococcus aureus