Molecular Characterization of Staphylococcus aureus Isolated from Human and Food Samples in Northern Algeria

Abstract

<i>Staphylococcus aureus</i> is a commensal resident of the skin and nasal cavities of humans and can cause various infections. Some toxigenic strains can contaminate food matrices and cause foodborne intoxications. The present study aimed to provide relevant information (clonal complex lineages, <i>agr</i> types, virulence and antimicrobial resistance-associated genes) based on DNA microarray analyses as well as the origins and dissemination of several circulating clones of 60 <i>Staphylococcus aureus</i> isolated from food matrices (<i>n</i> = 24), clinical samples (<i>n</i> = 20), and nasal carriers (<i>n</i> = 16) in northern Algeria. <i>Staphylococcus aureus</i> were genotyped into 14 different clonal complexes. Out of 60 <i>S. aureus</i>, 13 and 10 isolates belonged to CC1-MSSA and CC97-MSSA, respectively. The CC 80-MRSA-IV was the predominant <i>S. aureus</i> strain in clinical isolates. The accessory gene regulator allele <i>agr</i> group III was mainly found among clinical isolates (70.4%). Panton-Valentine leukocidin genes <i>luk</i>F/<i>luk</i>S-PV were detected in 13.3% of isolates that all belonged to CC80-MRSA. The <i>luk</i>F<i>/</i>S-<i>hlg</i>, <i>hlg</i>A, and <i>hla</i> genes encoding for hemolysins and leucocidin components were detected in all <i>Staphylococcus</i><i>aureus</i> isolates. Clinical and food isolates harbored more often the antibiotic resistance genes markers. Seventeen (28.3%) methicillin-resistant <i>Staphylococcus aureus</i> carrying the <i>mec</i>A gene localized on a SCC<i>mec</i> type IV element were identified. The penicillinase operon (<i>bla</i>Z/I/R) was found in 71.7% (43/60) of isolates. Food isolates belonging to CC97-MSSA carried several antibiotic resistance genes (<i>bla</i>Z, <i>erm</i>B, <i>aph</i>A3, <i>sat</i>, <i>tet</i>M, and <i>tet</i>K). The results of this study showed that all clones were found in their typical host, but interestingly, some nasal carriers had isolates assigned to CC705 thought to be absent in humans. The detection of MRSA strains among food isolates should be considered as a potential public health risk. Therefore, controlling the antibiotics prescription for a rational use in human and animal infections is mandatory.