Abstract
To investigate the distribution of twelve staphylococcal enterotoxin genes (se) and the toxic shock syndrome toxin-1 gene (tst) in Staphylococcus aureus, 140 community isolates from various origins were investigated. Isolates were collected, from 15 clinical laboratories located at Casablanca, between 2007 and 2008, they were identified by conventional methods, and methicillin resistance was confirmed by amplification of mecA gene by PCR. All isolates were searched using a multiplex PCR for the accessory gene regulator (agr) group, and for thirteen superantigen (SAg) toxin genes: sea, seb, sec, sed, seh, selk, sell, selm, selo, selp, selq, ser and tst. Among all isolates, only two were methicillin-resistant and one hundred seven were shown to be positive for at least one of the tested SAg toxin genes. They were grouped in 43 genotypes. Our work showed that agr group III and agr group I S. aureus isolates, were highly prevalent for the presence of seh, selq, selk and/or tst genes, on one hand, and sec and/or sell genes, on the other hand (P<0.05), respectively. In addition, we found a relationship between pus/ wound S. aureus isolates and the presence of selk + selq genes (P<0.05). Our results suggest that agr group III isolates carried more of SAg toxin genes than agr groups I and II S. aureus strains.
Highlights
Staphylococcus aureus is a major cause of multiple types of infections both in and outside of the hospital setting
A total of 140 S. aureus isolates were collected from clinical outpatient specimens at the Laboratory of Bacteriology, Institute Pasteur of Morocco (60% of isolates), and from 14 clinical laboratories located in Casablanca (40% of isolates)
The all 13 SAg toxin genes analysed in this study were detected; the prevalence were variable from 53.6% to 1.4%
Summary
Staphylococcus aureus is a major cause of multiple types of infections both in and outside of the hospital setting. Among the secreted virulence factors that have known roles in serious human diseases, are the staphylococcal superantigens (SAgs) [2,3] They includes toxic shock syndrome toxin-1 (TSST-1) [4], staphylococcal enterotoxin (SE) serotypes A, B, Cn (in which n denotes that multiple variant forms exist), D, E, G, H ,I , R, S, T and SE-like (SEls) serotypes J, K, L, M, N, O, P, Q, U, V [5,6,7]. These toxins are considered to be major virulence factors of S. aureus [3,5]. This association implies a horizontal transfer of the SAg toxin genes between staphylococcal strains and an important role in the evolution of S. aureus as a pathogen. [10,11,12,13,14]
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