Molecular Characterization and Antimicrobial Susceptibility of Staphylococcus aureus Isolates from Clinical Infection and Asymptomatic Carriers in Southwest Nigeria.
Few reports from Africa suggest that resistance pattern, virulence factors and genotypes differ between Staphylococcus aureus from nasal carriage and clinical infection. We therefore compared antimicrobial resistance, selected virulence factors and genotypes of S. aureus from nasal carriage and clinical infection in Southwest Nigeria. Non-duplicate S. aureus isolates were obtained from infection (n = 217) and asymptomatic carriers (n = 73) during a cross sectional study in Lagos and Ogun States, Nigeria from 2010-2011. Susceptibility testing was performed using Vitek automated systems. Selected virulence factors were detected by PCR. The population structure was assessed using spa typing. The spa clonal complexes (spa-CC) were deduced using the Based Upon Repeat Pattern algorithm (BURP). Resistance was higher for aminoglycosides in clinical isolates while resistances to quinolones and tetracycline were more prevalent in carrier isolates. The Panton-Valentine leukocidin (PVL) was more frequently detected in isolates from infection compared to carriage (80.2 vs 53.4%; p<0.001, chi2-test). Seven methicillin resistant S. aureus isolates were associated with spa types t002, t008, t064, t194, t8439, t8440 and t8441. The predominant spa types among the methicillin-susceptible S. aureus isolates were t084 (65.5%), t2304 (4.4%) and t8435 (4.1%). spa-CC 084 was predominant among isolates from infection (80.3%, n = 167) and was significantly associated with PVL (OR = 7.1, 95%CI: 3.9-13.2, p<0.001, chi2-test). In conclusion, PVL positive isolates were more frequently detected among isolates from infection compared to carriage and are associated with spa-CC 084.
Department of Biological Sciences, Covenant University, Ota, Ogun State, Nigeria.
Olayemi O
OO
Ayepola
Department of Microbiology, Lagos State University, Ojo, Lagos State, Nigeria.
Nurudeen A
NA
Olasupo
Department of Biological Sciences, Covenant University, Ota, Ogun State, Nigeria.
Louis O
LO
Egwari
Institute for Medical Microbiology, University Hospital Münster, Münster, Germany.
Karsten
K
Becker
Institute for Medical Microbiology, University Hospital Münster, Münster, Germany.
Frieder
F
Schaumburg
D001427:Bacterial Toxins / Q000235:genetics* / Q000302:isolation & purification; D005098:Exotoxins / Q000235:genetics* / Q000302:isolation & purification; D006801:Humans; D007956:Leukocidins / Q000235:genetics* / Q000302:isolation & purification; D008712:Methicillin / Q000627:therapeutic use; D016106:Methicillin Resistance / Q000235:genetics*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000472:pathogenicity; D008826:Microbial Sensitivity Tests; D009549:Nigeria / Q000453:epidemiology; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000235:genetics* / Q000382:microbiology
D001427:Bacterial Toxins; D005098:Exotoxins; D007956:Leukocidins; C078284:Panton-Valentine leukocidin; D008712:Methicillin