In the present study, we report data on virulence determinants of Staphylococcus aureus from stable nasal carriers, emphasizing on the genes encoding fibronectin (fnbA, fnbB) and collagen (cna) adhesive molecules. Of the 44 S. aureus isolates included, 32 isolates (16 pairs) were cultured from the anterior nares of 16 healthy carriers, eight isolates (four pairs) were collected from the nose of four patients with recurrent skin infections and four isolates were obtained from the infection site of these patients. The period between the two nasal swabs taken was 3-5 days. The persistency of carriage could be demonstrated by the indistinguishable genotypic characteristics of the S. aureus isolates in each pair. This could be shown by determination of gene polymorphisms of coa gene and the X-region and IgG-binding region encoding segments of spa gene. In addition, the isolates within the pairs showed identical toxin patterns. This was determined by PCR amplification of the genes encoding staphylococcal enterotoxins (SEA to SEJ) and TSST-1. The genotypic properties also yielded an identity between persistent nasal carriage isolates and the corresponding skin infection isolates of the four patients. In addition, all S. aureus nasal and skin infection isolates were positive for gene fnbA, fnbB and cna could be found with a high frequency. Among the 44 isolates investigated, 16 isolates (36.7%) harbored gene fnbB and 21 isolates (47.7%) gene cna. The data in the present study showed a relatively wide distribution of the genes fnb and cna among the investigated isolates, indicating that the persistent carriage of strains harboring these virulence determinants may increase the risk for subsequent invasive infections in carriers.

Aims:  To compare the distribution of genes encoding classical and newly described enterotoxins among Staphylococcus aureus, associated with carriage and infection. Methods and Results:  Forty‐five nasal isolates from carriers and 42 clinical isolates were included. The genes sea to see and seg to sei as well as sem, sen, seo and seu were tested using multiplex and conventional PCR. The most frequently found toxin genes were egc‐related genes, in particular the combination seg and sei (n = 55, 63·1%), followed by sen and seu (n = 54, 62·1%), sem (n = 51, 58·6%) and seo (n = 48, 55·2%). Significant differences were found for seg and sei combination (33 of the nasal vs 22 of the infection isolates, P = 0·048) as well as for the genes sem (P = 0·004), sen (P = 0·029) and seo (P = 0·032). Regarding the classical toxin genes no significant differences between the two groups of isolates were found. Conclusions:  Significant differences between infection and carriage strains were found only for the egc‐related genes, which were more common in the nasal isolates. Significance and Impact of the Study:  The egc‐related enterotoxin genes seem to be more prevalent in carriage‐ than in infection‐associated S. aureus isolates. The possible contribution of egc‐related genes in determining the potential for nasal carriage requires further investigation.

The present study was designed to investigate the significance and the relationship between nasal carriage of Staphylococcus aureus and staphylococcal skin infections. Thirty-one S. aureus strains, isolated from 12 patients with chronic and recurrent skin infections, one patient with septicemia and one patient with otitis externa were studied. The staphylococcal strains were isolated from the site of infection and from the anterior nares of each patient. The identity of both strains of each pair could be demonstrated by determination of phenotypic properties and by genotyping of the isolates. The phenotypic properties included hemolytic activities, antibiotic resistance data, and the production of enterotoxins. The identity was additionally confirmed by phage-typing, by determination of the size and the number of repeats of the X region of spa gene, by determination of gene polymorphisms of coa gene and by macrorestriction analysis of the chromosomal DNA of the isolates by pulsed-field gel electrophoresis. The present results showed an identity of the S. aureus obtained from anterior nares and from skin infection of each patient indicating the importance of nasal carriage of these bacteria for development of human skin infection. ß

The present study was designed to investigate the significance and the relationship between nasal carriage of Staphylococcus aureus and staphylococcal skin infections. Thirty-one S. aureus strains, isolated from 12 patients with chronic and recurrent skin infections, one patient with septicemia and one patient with otitis externa were studied. The staphylococcal strains were isolated from the site of infection and from the anterior nares of each patient. The identity of both strains of each pair could be demonstrated by determination of phenotypic properties and by genotyping of the isolates. The phenotypic properties included hemolytic activities, antibiotic resistance data, and the production of enterotoxins. The identity was additionally confirmed by phage-typing, by determination of the size and the number of repeats of the X region of spa gene, by determination of gene polymorphisms of coa gene and by macrorestriction analysis of the chromosomal DNA of the isolates by pulsed-field gel electrophoresis. The present results showed an identity of the S. aureus obtained from anterior nares and from skin infection of each patient indicating the importance of nasal carriage of these bacteria for development of human skin infection.

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