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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.

Antibiotics have components to inhibit infections against Staphylococcus aureus, but they depend on judicious use to minimize the incidence of resistance forms. Strategies to improve the current situation include research in finding a new antimicrobial from virgin coconut oil (VCO). The saturated fatty acid, lauric acid (LA) (C12) contain in VCO was reported to have antibacterial activities. This study developed antimicrobial of VCO as an antimicrobial and immunomodulatory agent. Staphylococcus aureus used in this study had been isolated and identified from the mastitis milk crossbreed Etawa goat from Riau, Indonesia. The susceptibility of S. aureus to VCO was tested using the broth dilution method. The inhibition mechanisms of S. aureus had been studied by scanning electron microscopy (SEM) after treatment with VCO, and potential of VCO, which is known in phagocytosis macrophage. In vitro test confirmed the inhibitory effect of VCO on the growth of S. aureus at the concentration of 200 μl (equal to 0.102 % LA). Based on the result of the phagocytosing assay, VCO could increase the ability of the macrophage cells to phagocyte S. aureus significantly at a concentration of 200 μL (equal to 0.102% LA). This study concluded that the VCO could inhibit the growth of S. aureus with destructive mechanisms of bacterial cell walls and increase the ability of the phagocytic immune cells.

The present study determined the genetic relationships between 41 Staphyloccocus (S.) aureus isolates from bovines, humans, and food using a single enzyme amplified fragment length polymorphism (AFLP) technique. We evaluated the prevalence of staphylococcal enterotoxin (SE) genes and other virulence gene determinants by PCR. The identification of S. aureus was based on culturing and biochemical tests, and by amplifying a specific section of the 23S rRNA gene. PCR amplification of the SE genes (sea, seb, sec, see, seg, seh, and sei) singly or in combination was observed. Most isolates of bovine origin harbored hla (84%) and cap5 (74%), while most isolates from humans harbored hla (73%), cap8 (91%), and fnbA (100%). Strains from food sources were positive for hla (100%), cap5 (100%), and cap8 (64%) unlike isolates from humans or bovines. A single enzyme AFLP analysis revealed a correlation between AFLP clusters of some strains and the source of the isolates The genotypic results of the present study might help to better understand the distribution of prevalent S. aureus clones among humans, bovines, and food and will help control S. aureus infections in Indonesia.

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