Cystic fibrosis (CF) patients have chronic airway infection and frequent exposure to antibiotics, which often leads to the emergence of resistant organisms. Achromobacter xylosoxidans is a new emergent pathogen in CF spectrum. From 2005 to 2010 we had an outbreak in A. xylosoxidans prevalence in our CF center, thus, the present study was aimed at deeply investigating virulence traits of A. xylosoxidans strains isolated from infected CF patients. To this purpose, we assessed A. xylosoxidans genome variability by randomly amplified polymorphic DNA (RAPD), biofilm production, antibiotic resistances, and motility. All A. xylosoxidans strains resulted to be biofilm producers, and were resistant to antibiotics usually employed in CF treatment. Hodge Test showed the ability to produce carbapenemase in some strains. Strains who were resistant to β-lactamics antibiotics, showed the specific band related to metal β-lactamase (blaIMP-1), and some of them showed to possess the integron1. Around 81% of A. xylosoxidans strains were motile. Multivariate analysis showed that RAPD profiles were able to predict Forced Expiratory Volume (FEV1%) and biofilm classes. A significant prevalence of strong biofilm producers strains was found in CF patients with severely impaired lung functions (FEV1% class 1). The outbreak we had in our center (prevalence from 8.9 to 16%) could be explained by an enhanced adaptation of A. xylosoxidans in the nosocomial environment, despite of aggressive antibiotic regimens that CF patients usually undergo.

Escherichia coli strains producing extended-spectrum ␤-lactamases (ESBLs) are a major problem in many different hospitals worldwide, causing outbreaks as well as sporadic infections. The prevalence of Escherichia coli ESBL producers was analyzed in a surveillance study performed on the population attending the Policlinico Umberto I, the largest university hospital in Rome, Italy. We also investigated genotypes, pathogenicity islands, and plasmids in the ESBL-positive E. coli isolates as further markers that are useful in describing the epidemiology of the infections. In this survey, 163 nonreplicate isolates of Escherichia coli were isolated from patients from 86 different wards, and 28 were confirmed as ESBL producers. A high prevalence (26/28) of CTX-M-15 producers was observed within the bacterial population circulating in this hospital, and the dissemination of this genetic trait was associated with the spread of related strains; however, these do not have the characteristics of a single epidemic clone spreading. The dissemination was also linked to horizontal transfer among the prevalent E. coli genotypes of multireplicon plasmids showing FIA, FIB, and FII replicons in various combinations, which are well adapted to the E. coli species. The analysis of related bacteria suggests a probable interpatient transmission occurring in several wards, causing small outbreaks.A rapid dissemination of isolates producing CTX-M-type extended-spectrum ␤-lactamases (ESBLs) has recently been reported in some European countries, including Italy, and is a matter of major concern. The bla CTX-M genes have been captured on transferable plasmids from the chromosomes of Kluyvera spp., and their products are becoming the most prevalent ESBLs encountered in Enterobacteriaceae (19). The prevalent bla CTX-M -type genes in Europe have been identified as bla CTX-M-1 , bla CTX-M-3 , bla CTX-M-9 , bla CTX-M-14 , and bla CTX-M-15 (2, 19). Infections caused by enterobacteria producing ESBLs are associated with increased morbidity, mortality, and health care-associated costs (9, 16).In Italy, the presence of CTX-M-type ESBLs in clinical isolates of Enterobacteriaceae examined in a Italian nationwide survey (23,27), as well as in isolates from companion animals (7), was previously reported, and the results showed that CTX-M-type enzymes were common overall (around 20%) among ESBL producers (20). However, the local epidemiology of Escherichia coli producing ESBLs may differ from the national picture, with dominance of different strains. We therefore studied the prevalence and the clonality of the Escherichia coli ESBL producers in the population attending the Policlinico Umberto I, the largest university hospital in Rome, Italy, which had not been included in the nationwide survey. We also investigated virulence factors encoded on pathogenicity islands (PAIs) and plasmids carried by the E. coli ESBL producers as further markers that are useful in describing the epidemiology of nosocomially acquired infections. MATERIALS AND METHODS Clinical i...

In this study 45 epidemic and sporadic isolates of Acinetobacter baumannii were investigated by antimicrobial resistance, integron identifications and genotyping. Isolates were genotyped by random amplified polymorphism (RAPD) DNA and pulsed-field gel electrophoresis (PFGE). Four different RAPD patterns were observed among the isolates of our collection, further discerned in six PFGE types. Two prevalent genotypes were identified, one corresponding to a carbapenem resistant epidemic clone, causing an outbreak at the intensive care unit of a hospital of Rome. Two class 1 integrons, carrying different gene cassette arrays, were identified among the two prevalent genotypes. Nucleotide analysis of the integron-variable regions revealed the presence of the aacA4, orfO, bla(OXA-20), and aacC1, orfX, orfX', aadA1 gene cassette arrays, respectively. All the carbapenem resistant strains analyzed in this study carried the bla (OXA-58) gene located on plasmids.

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