Clonal distribution of enterotoxigenic Staphylococcus aureus on handles of handheld shopping baskets in supermarkets.

AIMS: Shopping carts and handheld shopping baskets in supermarkets are subject to accidental bacterial contamination through contacts with a variety of food. We investigated the prevalence of Staphylococcus aureus on the handles of handheld shopping baskets in four supermarkets distantly located in Osaka district, Japan. METHODS AND RESULTS: Fifty two strains of Staph. aureus were isolated from 760 basket handles. Among these, six strains were positive for staphylococcal enterotoxin B (SEB) production, representing 12% of total. This SEB producer ratio is considerably higher than among Staph. aureus isolated from nasal swabs of the supermarket workers (2%) and from independently collected clinical specimens (4%). These SEB-producing Staph. aureus strains from the basket handles are clonal and belong to ST12. Coagulase typing showed that they are in group VII, which is the most common cause of food poisoning in Japan. Biofilm assays indicated that SEB gene (seb)-positive strains including this clone produced a significantly higher amount of biofilm than seb-negative strains. CONCLUSIONS: The frequent isolation of seb-positive Staph. aureus on shopping basket handles raises the possibility that they could be a hidden reservoir for Staph. aureus with a potential to cause food poisoning and draws attention to the importance of shopping basket sanitation.

Drug susceptibility and clonality of methicillin-resistant Staphylococcus epidermidis in hospitalized patients with hematological malignancies.

PURPOSE: To evaluate the clonal relatedness and drug susceptibility of Streptococcus epidermidis isolated from hematological patients. METHODS: All S. epidermidis isolated from hematological patients who developed bloodstream infections between June 2005 and December 2007 were included. The clonal relationship was tested by means of pulsed-field gel electrophoresis (PFGE) analysis. RESULTS: Fifteen methicillin-resistant S. epidermidis (MRSE) isolates were examined from patients' blood culture samples. Two subgroups that differed approximately by 40% in their PFGE banding were identified. In clinical practice, two cases were cured with cephalosporin only, thus demonstrating sensitivity of the strains to beta-lactam antibiotics. CONCLUSIONS: Our results represent two significant findings. One is the major capability of MRSE to colonize patients. The other is that some MRSE isolates proved to be sensitive to clindamycin, minocycline, and cephalosporin, so that using antibiotics to which MRSE is sensitive as first-line therapy can avoid the need for vancomycin in clinical settings.