Phylogenetic diversity of Klebsiella pneumoniae and Klebsiella oxytoca clinical isolates revealed by randomly amplified polymorphic DNA, gyrA and parC genes sequencing and automated ribotyping.
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The infra-specific phylogenetic diversity and genetic structure of both Klebsiella pneumoniae and Klebsiella oxytoca was investigated using a combination of randomly amplified polymorphic DNA (RAPD) analysis, sequencing of gyrA and parC genes, and automated ribotyping. After RAPD analysis with four independent primers of 120 clinical isolates collected from 22 European hospitals in 13 countries, K. pneumoniae isolates fell into three clusters and K. oxytoca isolates fell into two clusters, while Klebsiella planticola isolates formed a sixth cluster. Each cluster was geographically widespread. K. pneumoniae cluster I (KpI) accounted for 80% of the isolates of this species and included reference strains of the three subspecies K. pneumoniae subsp. pneumoniae, K. pneumoniae subsp. ozaenae and K. pneumoniae subsp. rhinoscleromatis. Clusters KpII and KpIII were equally represented, as were the two K. oxytoca clusters. Individualization of each cluster was fully confirmed by phylogenetic analysis of gyrA and parC gene sequences. In addition, sequence data supported the evolutionary separation of K. pneumoniae from a phylogenetic group including K. oxytoca, Klebsiella terrigena, K. planticola and Klebsiella ornithinolytica. Automated ribotyping using Mlu I appeared suitable for identification of each Klebsiella cluster. The adonitol fermentation test was found to be useful for cluster identification in K. pneumoniae, since it was negative in all strains of clusters KpIII and in some KpII strains, but always positive in cluster KpI. The usefulness of gyrA and parC sequence data for population genetics and cluster identification in bacteria was demonstrated, even for the phylogenetic positioning of quinolone-resistant isolates. (+info)
Phylogenetic analyses of Klebsiella species delineate Klebsiella and Raoultella gen. nov., with description of Raoultella ornithinolytica comb. nov., Raoultella terrigena comb. nov. and Raoultella planticola comb. nov.
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The phylogenetic relationships of the type strains of 9 Klebsiella species and 20 species from 11 genera of the family Enterobacteriaceae were investigated by performing a comparative analysis of the sequences of the 16S rRNA and rpoB genes. The sequence data were phylogenetically analysed by the neighbourjoining and parsimony methods. The phylogenetic inference of the sequence comparison confirmed that the genus Klebsiella is heterogeneous and composed of species which form three clusters that also included members of other genera, including Enterobacter aerogenes, Erwinia clusters I and II and Tatumella. Cluster I contained the type strains of Klebsiella pneumoniae subsp. pneumoniae, Klebsiella pneumoniae subsp. rhinoscleromatis and Klebsiella pneumoniae subsp. ozaenae. Cluster II contained Klebsiella ornithinolytica, Klebsiella planticola, Klebsiella trevisanii and Klebsiella terrigena, organisms characterized by growth at 10 degrees C and utilization of L-sorbose as carbon source. Cluster III contained Klebsiella oxytoca. The data from the sequence analyses along with previously reported biochemical and DNA-DNA hybridization data support the division of the genus Klebsiella into two genera and one genogroup. The name Raoultella is proposed as a genus name for species of cluster II and emended definitions of Klebsiella species are proposed. (+info)
Incidence of Klebsiella species in surface waters and their expression of virulence factors.
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To investigate the occurrence of different Klebsiella spp. in aquatic environments, a total of 208 samples of natural surface waters was examined. From half (53%) of these samples, 123 Klebsiella strains were isolated, the most common species being Klebsiella pneumoniae. A comparison of these isolates to a group of 207 clinical K. pneumoniae isolates demonstrated that water isolates of K. pneumoniae, unlike those of K. oxytoca and K. planticola, are as capable as clinical isolates of expressing putative virulence factors such as serum resistance and capsular polysaccharides, pili, and siderophores. (+info)
CMY-2-producing Salmonella enterica, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis and Escherichia coli strains isolated in Spain (October 1999-December 2000).
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CMY-2 plasmid-mediated AmpC beta-lactamase (CMY-2) was detected in 21 isolates from two hospitals located in different geographical regions of Spain between October 1999 and December 2000. The isolates comprised two Salmonella enterica serovars (Mikawasima and Montevideo), 16 Escherichia coli, one Klebsiella pneumoniae, one Klebsiella oxytoca and one Proteus mirabilis. In addition to the expected resistance to beta-lactams, including extended-spectrum cephalosporins and cefoxitin, all isolates showed a broad spectrum of associated resistance. All were resistant to sulfamethoxazole, chloramphenicol, tetracycline and streptomycin, and all but two were also resistant to gentamicin. Five isolates were studied in detail and all transferred CMY-2 and other resistance determinants by conjugation. Genomic DNA restriction pattern analysis of the E. coli isolates excluded the dissemination of a single clone. To the best of our knowledge this is the first time that CMY-2 has been detected in P. mirabilis, K. oxytoca and S. enterica serovars Mikawasima and Montevideo. It is also the first time that CMY-2 has been described in Spain. (+info)
Activity of ertapenem (MK-0826) versus Enterobacteriaceae with potent beta-lactamases.
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Ertapenem (MK-0826; L-749,345), a new carbapenem with a long serum half-life, was tested, in vitro, against beta-lactamase-producing bacteria. The new compound had a MIC at which 90% of the isolates were inhibited of 0.06 microg/ml for extended-spectrum beta-lactamase (ESBL)-producing klebsiellas, compared with 0.5 microg/ml for imipenem, 16 microg/ml for cefepime, and >128 microg/ml for ceftazidime and piperacillin-tazobactam. MICs of ertapenem for AmpC-derepressed mutant Enterobacteriaceae were 0.015 to 0.5 microg/ml, whereas imipenem MICs were 0.25 to 1 microg/ml and those of cefepime were 0.5 to 4 microg/ml, and resistance to ceftazidime and piperacillin-tazobactam was generalized. Despite this good activity, the MICs of ertapenem for ESBL-positive klebsiellas mostly were two- to fourfold above those for ESBL-negative strains, and the MICs for AmpC-hyperproducing Enterobacter cloacae and Citrobacter freundii mutants exceeded those for the corresponding AmpC-basal mutants. These differentials did not increase when the inoculum was raised from 10(4) to 10(6) CFU/spot, contraindicating significant lability. Carbapenemase producers were also tested. The IMP-1 metallo-beta-lactamase conferred substantial ertapenem resistance (MIC, 128 microg/ml) in a porin-deficient Klebsiella pneumoniae strain, whereas a MIC of 6 microg/ml was recorded for its porin-expressing revertant. SME-1 carbapenemase was associated with an ertapenem MIC of 2 microg/ml for Serratia marcescens S6, compared with <0.03 microg/ml for Serratia strains lacking this enzyme. In summary, ertapenem had good activity against strains with potent beta-lactamases, except for those with known carbapenemases. (+info)
Immune sensitization to food, yeast and bacteria in Crohn's disease.
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BACKGROUND: Complex food proteins and enteric flora may act as antigenic stimuli in Crohn's disease. This study assessed the prevalence and magnitude of lymphocyte priming to these antigens in Crohn's disease. METHODS: A total of 31 Crohn's disease patients (median age 42 years, range 25-72 years) and 22 healthy controls (median 29 years, 23-43 years) were studied. Peripheral blood lymphocytes were collected and incubated with antigens in hanging drop culture for 4 days. The antigens tested were cow's milk, cereals, cabbage group, citrus group, peanut group, Saccharomyces (yeast), Bacteroides, E. coli and Klebsiella. On the 4th day 3H-thymidine incorporation was measured after a 4-h pulse. Responses to antigens were considered positive if mean proliferative values were above the 99% confidence interval for background proliferation. RESULTS: The mean background and mitogen-stimulated proliferation did not differ between patients and controls. The mean proliferation to antigens was not above background in controls, but in Crohn's patients proliferative responses to all food and bacterial antigens were significantly higher than background values. Twenty-three out of 31 Crohn's patients and five out of 22 controls (P=0.0003) responded to one or more antigens. Sixteen Crohn's patients and two controls responded to four or more antigens (P=0.001, Fisher's exact test). CONCLUSION: The reactivity of peripheral lymphocytes to food, yeast and bacterial antigens, especially multiple antigens, is common in Crohn's disease. These sensitized lymphocytes may contribute to the inflammatory process. (+info)
Increased prevalence of class I integrons in Escherichia coli, Klebsiella species, and Enterobacter species isolates over a 7-year period in a German university hospital.
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The prevalence of integrons in five enterobacterial species was analyzed in 900 blood culture isolates from 1993, 1996, and 1999. Remarkably, the prevalence increased from 4.7% in 1993 to 9.7% in 1996 and finally to 17.4% in 1999 (P < 0.01). Within 7 years the combined percentage of P1 strong promoters and P1 weak plus P2 active promoters with high transcription efficacies has increased from 23.1 to 33.3 and finally 60% (P < 0.05). (+info)
Delayed referral reduces the success of video-assisted thoracoscopic debridement for post-pneumonic empyema.
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The aim of this study was to evaluate the effect of preoperative delay on the efficacy of video-assisted thoracoscopic surgery (VATS) for post-pneumonic pleural empyema (PPE). This was a prospective study of 39 consecutive patients with PPE who were treated by VATS with curative intent over a 4-year period. Failure to obtain full lung re-expansion resulted in conversion to thoracotomy. Pre- and post-operative variables were correlated with surgical outcome. VATS debridement was successful in 16 (41%) patients while conversion to open decortication was needed in 23 patients (21 immediate, two delayed), There was no difference in the age/sex distribution of the two groups. In the failed VATS group the delay from hospital admission to operation was longer: 24 (2.1) vs. 16.6 (2.7) days (P = 0.03, 95% CI 0.53-14.3 days); operating time was longer: 128.2 (7.9) vs. 86.2 (10.4) min (P = 0.003, 95% CI 15.2-68.5 min) and post-operative stay was longer: 8.4 (0.8) vs. 5.2 (0.6) days (P = 0.03, 95% CI 1.1-5.3 days). VATS can be used successfully to treat PPE with a faster post-operative recovery when successful than open surgery. Delayed surgical intervention decreases the success of VATS thus earlier referral for surgical intervention in PPE (ideally within 21 days) is advocated to gain its full benefits. (+info)