Toxic shock syndrome toxin-1 (TSST-1) production and phage susceptibility of Staphylococcus aureus strains from human vaginas and anterior nares in Trinidad

Abstract

The carriage rates of Staphylococcus aureus in the anterior nares of children and women as well as in the vagina of women were determined. The ability of strains of S. aureus to produce toxic shock syndrome toxin-1 (TSST-1) and their susceptibility to phages of the international phage set (IPS) for human strains were also investigated. Of 200 women studied, the carriage rate of S. aureus in high vaginal swabs and anterior nares swabs was 57 (28.5%) and 73 (36.5%), respectively. Eight (4.0%) and 16 (8.0%) patients were carriers of TSST-1-producing strains in their vaginas and anterior nares, respectively. Amongst the 220 children sampled, 100 (45.5%) were carriers of S. aureus in their anterior nares, with 51 (23.2%) children being positive for TSST-1 producing strains. Overall, of the 233 strains of S. aureus isolated from all sources 176 (75.5%) were typable and 75 (32.2%) were positive for TSST-1 production. For strains from anterior nares, isolates from children were more susceptible (81.2%) to IPS phages than those from women (67.1%) but the difference was not significant (P > or = 0.05; chi 2). Forty-five (76.3%) of 59 strains of vaginal origin were typable. The frequency of production of TSST-1 amongst strains isolated from children, i.e. (50.5% (51 of 101), was significantly higher (P > or = 0.001; chi 2) than that found for isolates from women's anterior nares (21.9%) and vagina (13.6%). S. aureus was recovered from both the anterior nares and vaginal swabs of 11 patients sampled. The phage patterns of 5 of the 6 typable pairs of isolates established their relatedness suggesting that the same strains colonized the anterior nares and vagina of each of these patients. It was concluded that the carriage of TSST-1-producing strains of S. aureus in the anterior nares and vagina of women was much lower than that detected in children's anterior nares and that the risk of vaginal toxic shock syndrome (TSS) in Trinidadian women was relatively low. Susceptibility of strains was high to IPS phages. Epidemiological significance was attributed to the finding that the same strains of S. aureus colonized the anterior nares and vaginas of some women.