Nasal carriage of <i>Staphylococcus aureus</i> has been identified as a risk factor for the development of staphylococcal infections caused by endogenous colonizing strains. Information on the genotypic di...Nasal carriage of <i>Staphylococcus aureus</i> has been identified as a risk factor for the development of staphylococcal infections caused by endogenous colonizing strains. Information on the genotypic diversity of <i>Staphylococcus aureus</i> is relevant for managing epidemiological and clinical challenges resulting from the evolutionary differences of this bacterium. The objective of this study was to determine and compare the molecular diversity of <i>Staphylococcus aureus</i> isolates from three high-risk populations in Yaounde, Cameroon. Molecular analysis confirmed that 95% of 100 tested isolates were <i>S. aureus</i>. The <i>mec</i>A and Panton Valentine-Leukocidin (PVL) genes (<i>lukS/F-PV</i>) were detected in 37% (35/95) and 43% (41/95) of isolates respectively and 18% (17/95) of the isolates harboured both the <i>mec</i>A and <i>lukS/F-PV</i> genes. A mixed distribution of both methicillin sensitive <i>S. aureus</i> (MSSA)/PVL and methicillin resistant <i>S. aureus</i> (MRSA)/PVL strains were detected within the study population. Community associated MRSA accounted for 94% (33/35) of the isolates, further classified into allotypes SCC<i>mec</i> type IV 54% (19/35) and SCC<i>mec</i> type V 40% (14/35), while two isolates were hospital associated SCC<i>mec</i> type II strains. A majority of the isolates harboured a single aggressive gene regulator allele <i>agr</i> type I. Pulsed Field Gel Electrophoresis (PFGE) generated 18 pulsotypes that grouped isolates irrespective of the study population. Multilocus Sequence Typing (MLST) of 12 selected isolates was assigned to six pandemic clonal complexes (CC): CC5 (ST5), CC8 [ST8, (n = 3)], CC15 (ST 15), CC25 (ST 25), CC72 [ST72 (n = 2)] and CC121 [ST 121 (n = 2)] and three atypical sequence types ST 508, ST 699 (CC45) and ST 1289 (CC 88). The study population represents an important reservoir for MRSA, MRSA-PVL and MSSA-PVL which could serve as focal point for further dissemination bringing about significant clinical and epidemiological implications. The predominance of SCC<i>mec</i> IV and <i>agr</i> types in this setting warrants further investigation. Isolates were genetically diverse with MLST indicating that pandemic ST8 was predominant. Detection of atypical STs has provided an insight into the necessity for constant monitoring.展开更多
文摘Nasal carriage of <i>Staphylococcus aureus</i> has been identified as a risk factor for the development of staphylococcal infections caused by endogenous colonizing strains. Information on the genotypic diversity of <i>Staphylococcus aureus</i> is relevant for managing epidemiological and clinical challenges resulting from the evolutionary differences of this bacterium. The objective of this study was to determine and compare the molecular diversity of <i>Staphylococcus aureus</i> isolates from three high-risk populations in Yaounde, Cameroon. Molecular analysis confirmed that 95% of 100 tested isolates were <i>S. aureus</i>. The <i>mec</i>A and Panton Valentine-Leukocidin (PVL) genes (<i>lukS/F-PV</i>) were detected in 37% (35/95) and 43% (41/95) of isolates respectively and 18% (17/95) of the isolates harboured both the <i>mec</i>A and <i>lukS/F-PV</i> genes. A mixed distribution of both methicillin sensitive <i>S. aureus</i> (MSSA)/PVL and methicillin resistant <i>S. aureus</i> (MRSA)/PVL strains were detected within the study population. Community associated MRSA accounted for 94% (33/35) of the isolates, further classified into allotypes SCC<i>mec</i> type IV 54% (19/35) and SCC<i>mec</i> type V 40% (14/35), while two isolates were hospital associated SCC<i>mec</i> type II strains. A majority of the isolates harboured a single aggressive gene regulator allele <i>agr</i> type I. Pulsed Field Gel Electrophoresis (PFGE) generated 18 pulsotypes that grouped isolates irrespective of the study population. Multilocus Sequence Typing (MLST) of 12 selected isolates was assigned to six pandemic clonal complexes (CC): CC5 (ST5), CC8 [ST8, (n = 3)], CC15 (ST 15), CC25 (ST 25), CC72 [ST72 (n = 2)] and CC121 [ST 121 (n = 2)] and three atypical sequence types ST 508, ST 699 (CC45) and ST 1289 (CC 88). The study population represents an important reservoir for MRSA, MRSA-PVL and MSSA-PVL which could serve as focal point for further dissemination bringing about significant clinical and epidemiological implications. The predominance of SCC<i>mec</i> IV and <i>agr</i> types in this setting warrants further investigation. Isolates were genetically diverse with MLST indicating that pandemic ST8 was predominant. Detection of atypical STs has provided an insight into the necessity for constant monitoring.
