Molecular characterization of Salmonella isolates by REP-PCR and RAPD analysis.

Eighteen Salmonella isolates from both human and food (non-human) sources (fish, meat, and poultry) were characterized using conventional culture methods, biochemical, serological, and molecular analyses. REP-PCR and RAPD produced DNA profiles for differentiation purposes. Enterobacterial repetitive intergenic consensus (ERIC), repetitive extragenic palindronic (REP) and BOXAIR primers were selected for REP-PCR and two arbitrary primers, namely OPP-16 and OPS-11 were used for RAPD to generate DNA fingerprints from the Salmonella isolates. REP-PCR method showed greater discriminatory power in differentiating closely related strains of the related strains of Salmonella and produced more complex banding patterns as compared with RAPD. A dendogram was constructed with both sets of profiles using SPSS Version 13.0 computer software and showed that most human isolates were separately clustered from the non-human isolates. Two of the human isolates were closely related to some of the non-human isolates. A good correlation was also observed between the serogrouping of the O antigen and the molecular profiles obtained from REP-PCR and RAPD data of the Salmonella isolates. The results of a principal coordinate analysis (PCA) corresponded to the clustering in the dendrogram.

Antimicrobial resistance among enterobacteriaceae causing uncomplicated urinary tract infections in Mauritius: consequences of past misuse of antibiotics.

A study was conducted to determine the nature and antimicrobial susceptibility of uropathogens in Mauritius in order to provide guidance on the empirical treatment of uncomplicated urinary tract infections. The study was based on urine samples sent for bacteriological investigation at the Central Health Laboratory from unhospitalized patients over a 3-month period. Information on organisms isolated in pure growth and their antibiotic susceptibility was collected and analyzed. Entero - bacteriaceae accounted for over 80% of the 260 isolates obtained during the study period, and showed high rates of resistance to ampicillin (80%), co-trimoxazole (50%), nalidixic acid (34%) and ciprofloxacin (26%). Resistance to mecillinam and fosfomycin were only 2% and 0% respectively. The high rate of antimicrobial resistance in Enterobacteriaceae in urine is cause for concern. Fluoroquinolones may not be very reliable for empirical treatment of urinary tract infections in Mauritius. Alternatives such as pivmecillinam and fosfomycin should be considered.

Serotyping and RAPD profiles of Salmonella enterica isolates from Mauritius.

AIMS: The genus Salmonella is a common agent of gastroenteritis in Mauritius, generating more cases of the disease during summer than during winter. The aims of this study were to assess the genetic diversity of isolates of Salmonella enterica by RAPD fingerprinting, and to establish the relationship between human and chicken isolates. METHODS: Twenty-six isolates were obtained from hospital laboratories and commercial poultry producers locally. RESULTS: The RAPD profiles, biochemical and serological analyses showed that two of the chicken isolates were mistakenly identified as Salmonella. The genetic diversity of the remaining 24 isolates (five chicken and 19 human), confirmed as Salmonella, was analysed using four arbitrary primers, OPA-10, OPR-03, OPI-06 and OPJ-09, chosen from an initial set of 10 decamers. Seventy RAPD markers were generated in four individual DNA profiles. SIGNIFICANCE AND IMPACT OF THE STUDY: Cluster analysis (UPGMA) performed using the NTSYS-pc V 1.8 computer software, confirmed that some strains of Salmonella isolated from chicken were genetically similar to those isolated from humans. Furthermore, a 1 kbp band amplified using primer OPA-10 was specific for the Salmonella genus as it was not amplified in any of the control bacteria.

Investigation of an outbreak of vancomycin-resistant Enterococcus faecium by random amplified polymorphic DNA (RAPD) assay.

In this study, 122 isolates of vancomycin-resistant Enterococcus faecium (VREF) obtained from 103 patients over a four-year period in a London teaching hospital, were typed by a random amplified polymorphic DNA method. All the isolates exhibited high-level resistance to vancomycin (MIC 128-1024 mg/L), and were resistant to teicoplanin (32-256 mg/L). Nine RAPD types were distinguished by using a single primer. Clustering of certain types in time and space was noted. These results suggest that although several different strains of VREF were involved in this outbreak, cross-infection with individual types occurred on some wards. RAPD is a useful technique for the investigation of the epidemiology of VREF.

Mupirocin-resistant Staphylococcus aureus in a specialist school population.

Staphylococcus aureus strains resistant to mupirocin (MIC > 4000 mg l-1) were recovered from children and staff at a school for children with eczema and/or asthma or cystic fibrosis after mupirocin had been used to treat eczematous lesions. At least three distinct strains of S. aureus were involved and resistance was shown to be due in most isolates to a transmissible plasmid. The need for monitoring the extended use of this valuable antibiotic is emphasized.