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Aeromonas peritonitis remains a rare condition. In this study we describe the clinical features of primary and secondary Aeromonas peritonitis, and compare the differences between these two diseases entities. Patients with Aeromonas peritonitis were identified from microbiological and medical records during the period between March 1994 and March 2003. Clinical characteristics, laboratory data, microbiological results, treatment and outcome of patients were obtained by retrospective chart review. 22 and 27 patients with primary or secondary peritonitis caused by Aeromonas species were identified. All except two of these patients were adults, with a median age of 62.4 (31-76) vs 65.8 (8-85) years, respectively. Males were predominant (82 vs 78%). Peritonitis was community acquired in 73% and 56% of patients in these two groups, respectively. Significantly higher prevalence of underlying liver cirrhosis (96 vs 7%, p

An outbreak caused by rapid spread of methicillin-resistant Staphylococcus aureus (MRSA) in an intensive care unit for cardiovascular surgery was investigated by phenotypic and genotypic methods. Fourteen isolates were collected during a 2-month period from clinical and environmental specimens in the unit recently re-opened after reconstruction. The isolates were tested for antibiotic susceptibility patterns and genotyped by automated ribotyping, randomly amplified polymorphic DNA-PCR (RAPD) analysis and pulsed-field gel electrophoresis (PFGE). Automated ribotyping applying EcoRI digestion proved to be of no value in separating the isolates. In contrast, PFGE grouped the isolates into four clusters different from the reference strain. These results fully correlated with the antibiograms. Twelve of the isolates were grouped into two clonally related clusters. RAPD analyses grouped the isolates into five clusters. Except for two isolates of one patient, which had different RAPD patterns, PFGE and RAPD analyses presented very similar results. The results verified the usefulness of PFGE in studies of MRSA epidemics. A combination of these two methods reduces the time to identification of an outbreak and increases the accuracy in detection of intraspecies differences.

Correlation between in vitro susceptibility results for amoxicillin-clavulanate (AMC) and ampicillin-sulbactam (SAM) was studied using 136 clinical and control strains of Enterobacteriaceae harboring TEM-1, SHV-1 or OXA-1-like beta-lactamases. Determination of minimal inhibitory concentration of antibiotics was performed by agar dilution. The beta-lactamases were initially characterized using isoelectric focusing. Further identification was done by DNA hybridization with or without prior PCR amplification. All strains sensitive to SAM were found to be sensitive also to AMC. In contrast, among those susceptible to AMC, only 50% were sensitive to SAM while 36% gave intermediate results and 14% were resistant. Major differences were found solely among SHV-producers while minor differences occurred mostly among TEM-producers. This phenomenon is probably related to the differential activities of clavulanate and sulbactam against various beta-lactamases. In conclusion, testing of Enterobacteriaceae isolates for susceptibility to AMC and SAM should be performed and reported individually to avoid erroneous designation of susceptibility.