The Journal of hospital infection
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Comparative Study
Molecular biology of extended-spectrum beta-lactamase-producing Enterobacteriaceae responsible for digestive tract colonization.
Twenty-nine extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae strains (14 Klebsiella pneumoniae, 10 Escherichia coli and five Citrobacter diversus) isolated from April to July 1996 from faecal carriers in a surgical intensive care unit at the university hospital of Casablanca (Morocco) were studied. Plasmid content and DNA macrorestriction polymorphism determined by pulsed-field gel electrophoresis (PFGE) were used to compare the strains. Restriction profiles of total genomic DNAs cleaved by XbaI and compared by PFGE revealed nine, four and two clones in K. pneumoniae, E. coli and C. diversus, respectively. ⋯ No plasmid transfer could be obtained from C. diversus strains. Restriction enzyme digests of plasmids from transconjugants (four transconjugants of K. pneumoniae and five transconjugants of E. coli) showed different patterns. In the surgical intensive care unit where the survey was conducted, the dissemination of ESBLs was due to a mix of strain spread and strain diversity rather than to plasmid dissemination.
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Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in patients on mechanical ventilation and results in increases in mortality, prolonged hospitalization and costs. Preventive measures for VAP are well-documented and evidence-based, yet remain poorly implemented in most intensive care units. We undertook an observational pre and post-intervention study to assess whether an educational programme focusing on preventive practices for VAP could reduce the incidence. ⋯ VAP infection rates reduced by 51%, from a mean of 13.2+/-1.2 in the pre-intervention period to 6.5+/-1.5/1000 device days in the post-intervention period (mean difference 6.7; 95% CI: 2.9-10.4, P =0.02). A multidisciplinary educational programme geared towards intensive care unit staff can successfully reduce the incidence rates of VAP. Further studies will be needed to assess the impact on broader outcome measures such as costs or mortality.
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Comparative Study
Pulse-field gel electrophoresis typing of methicillin-resistant Staphylococcus aureus strains susceptible to aminoglycosides isolated from 1993 to 2002.
Methicillin-resistant Staphylococcus aureus (MRSA) susceptible strains to aminoglycosides (AS-MRSA) have been increasingly isolated in the Albert Cheneiver Hospital during the past 10 years. The aim of this study was first, to analyse the genotypes and the profiles of resistance to antibiotics and second to compare the AS-MRSA with the MRSA resistant to gentamicin (GR-MRSA) and with MRSA resistant to kanamycin and tobramycin, but susceptible to gentamicin (GS-MRSA), previously studied in our laboratory. All the AS-MRSA consecutively isolated from clinical samples (carriage isolates excluded) from 01/01/1993 to 31/12/2002 (33 isolates) were typed by DNA macrorestriction. ⋯ The diversity of our isolates showed that it was not an epidemic phenomenon, in contrast to the results of similar studies. Our findings may be explained by the patients coming mostly from different hospital units. This work indicates the need for further studies on the genome, to determine whether AS-MRSA have derived from strains that occurred before aminoglycosides came into clinical use.
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Methicillin-resistant Staphylococcus aureus (MRSA) predominantly affects those over 65 years old. There may be a substantial pool of older people with MRSA in the community. We studied the prevalence in one London general practice, screening 258 older people living in their own home. ⋯ The results of this and other studies suggest that national guidelines recommending early discharge for MRSA carriers have not resulted in widespread community acquisition amongst elderly people living in their own home. Community antibiotic policies for skin and soft-tissue infection do not require amendment. Patients with previous MRSA should be isolated and screened on admission especially to high-risk units.