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Streptococcus bovis is being recognised increasingly as a cause of infective endocarditis, and has also been associated with underlying gastrointestinal malignancy. This study evaluated the molecular epidemiology of S. bovis isolates responsible for endocarditis or bacteraemia in Italian patients between January 1990 and August 2003. S. bovis isolates were classified on the basis of their biochemical profiles, antimicrobial susceptibilities and genotypes. Of 25 isolates studied, 20 were S. bovis I and five were S. bovis II. Seven biochemical profiles were identified. Pulsed-field gel electrophoresis (PFGE) analysis identified 22 profiles that differed by at least two DNA fragments and showed a similarity of < 87%. Most PFGE patterns represented single isolates that differed in antimicrobial susceptibility, but three PFGE types were observed, with identical profiles and antibiotypes, in isolates from two different patients. S. bovis I and II isolates grouped into two distinct genetic clusters (I and II) with a similarity coefficient of 38%. Two sub-clusters (Ia and Ib), with a similarity coefficient of 47%, included 17 S. bovis I isolates with similar biochemical profiles (15 with biotype A, and two with biotype B), but different resistance phenotypes. Based on the phenotypic and genotypic heterogeneity of the isolates, it is postulated that the increase in S. bovis endocarditis in this geographical area might have been caused by the selection of sporadic endemic clones from the endogenous intestinal flora. [ABSTRACT FROM AUTHOR]

This study investigated the molecular epidemiology of a clonal outbreak of multidrug-resistant Acinetobacter baumannii that occurred between June 2003 and June 2004 in a tertiary-care hospital in Naples, Italy. A. baumannii was isolated from 74 patients, of whom 38 were infected and 36 were colonised. Thirty-three patients had ventilator-associated pneumonia, three had hospital-acquired pneumonia, and two had sepsis. Genotypic analysis of 45 available A. baumannii isolates revealed two distinct pulsed-field gel electrophoresis (PFGE) patterns. Of these, PFGE pattern 1 was represented by isolates from 44 patients and was identical to that of an epidemic A. baumannii clone isolated in another hospital of Naples during 2002. All A. baumannii isolates of PFGE type 1 showed identical multiresistant antibiotypes, characterised by resistance to all antimicrobial agents tested, including carbapenems, with the exception of colistin. In these isolates, inhibition of OXA enzymes by 200 mM NaCl reduced the imipenem MIC by up to four-fold. Molecular analysis of antimicrobial resistance genes showed that all A. baumannii isolates of PFGE type 1 harboured a class 1 integron containing the aacA4, orfX and blaOXA-20 gene cassettes, an ampC gene and a blaOXA-51-like allele. Moreover, a blaOXA-58-like gene surrounded by the regulatory elements IS Aba2 and IS Aba3 was identified in a 30-kb plasmid from A. baumannii isolates of PFGE type 1, but not PFGE type 2. Thus, selection of a single A. baumannii clone producing an OXA-58-type carbapenem-hydrolysing oxacillinase was responsible for the increase in the number of A. baumannii infections that occurred in this hospital. [ABSTRACT FROM AUTHOR]