ABSTRACT
The purpose of this study was to evaluate the possibility of using a semi-automated repetitive DNA sequences-based polymerase chain reaction (rep-PCR) for typing Pseudomonas aeruginosa isolates. rep-PCR profiles obtained by the DiversiLab system of 84 P. aeruginosa isolates from distinct epidemiological situations were obtained. rep-PCR groupings were in good agreement with the origin of these isolates. Linked rep-PCR profiles were observed for isolates recovered from a same family of cystic fibrosis (CF) patients, for the etiological agents of clustered cases of nosocomial infections, and for some isolates recovered from a same hospital room. rep-PCR and pulsed-field gel electrophoresis SpeI restricted genomic DNA (PFGE-SpeI) profiles were compared. In a few instances, rep-PCR revealed genetic divergences among isolates of a same group of PFGE-SpeI profiles. These divergences could reflect genetic drifts among closely related isolates, as illustrated by those observed between clinical and environmental isolates of a same group of PFGE-SpeI profiles. The interpretation of such differences will require further studies, but the rep-PCR analysis of P. aeruginosa diversity appeared to be an appropriate method to investigate infra-specific genetic relatedness.
Subject(s)
Automation/methods , Bacterial Typing Techniques/methods , DNA Fingerprinting/methods , Polymerase Chain Reaction/methods , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/classification , Pseudomonas aeruginosa/genetics , DNA, Bacterial/genetics , Humans , Interspersed Repetitive Sequences , Molecular Epidemiology/methods , Pseudomonas Infections/epidemiology , Pseudomonas aeruginosa/isolation & purificationABSTRACT
From 5 March 2001 to 19 October 2001, outbreaks of broncho-alveolar lavage (BAL) contamination with Enterobacteraceae were detected in our 700-bed institution. We report the investigation of these outbreaks. A case was defined as the occurrence of pairs of specific Enterobacteraceae in BAL specimens among any patients who underwent bronchoscopy in the respiratory unit during the period of the outbreak. Contamination was identified in 117 BAL samples during three outbreaks among 418 patients, and was associated with bronchoscopes 11 and 12 (P<0.001). The other five devices in use were not linked with the outbreaks. During the first outbreak, particular pairs of micro-organisms were associated with a specific bronchoscope (Klebsiella pneumoniae/Proteus vulgaris with bronchoscope 11, and Morganella morganii/Proteus mirabilis with bronchoscope 12). Cultures of sputa from two patients also yielded M. morganii some days after bronchoscopic examination. Isolates from contaminated BAL samples and bronchoscope 11 had similar patterns by pulsed-field gel electrophoresis. No further cases occurred after removal of the implicated bronchoscopes. No deficiencies in disinfection procedures were detected and the source of contamination was found to be a loose port of the biopsy channel of the bronchoscope. Our findings underscore the urgent need to test bronchoscopic samples regularly and to improve the design and structure of bronchoscopes.
Subject(s)
Bronchoscopes/microbiology , Cross Infection/epidemiology , Disease Outbreaks , Enterobacteriaceae Infections/epidemiology , Enterobacteriaceae/isolation & purification , Bronchoalveolar Lavage Fluid/microbiology , Bronchoscopy/adverse effects , Cross Infection/transmission , Enterobacteriaceae Infections/transmission , Equipment Contamination , France/epidemiology , HumansABSTRACT
The increasing hospital-to-hospital transmission of multiple drug-resistant bacteria is a major concern for bacteriology laboratories involved in nosocomial infection control. The interlaboratory reproducibility of pulsed-field gel electrophoresis (PFGE) for Pseudomonas aeruginosa typing was evaluated by asking four hospital laboratories (two in Lyon, one in Brest, and one in Marseille) to study 11 P. aeruginosa isolates, some of which were epidemiologically related, and the reference strain ATCC 27853. Two laboratories used the Genepath system, one the Chef DR II, system, and one the Chef Mapper system, Bio-Rad, restriction/Spe I. Profiles were read visually and by computerized comparison of restriction band molecular weights (Taxotron, software, PAD Grimont, Pasteur Institute, Paris, France). These two methods led to similar epidemiological conclusions. However, centralization of the data showed poor center-to-center reproducibility due to inadequate standardization of the procedure.
