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      Horizontol dissemination of TEM- and SHV-typr beta-lactamase genes-carrying resistance plasmids amongst clonical isolates of Enterobacteriaceae Translated title: Disseminação horizontal de plasmídios de resistência contendo genes de beta-lactamase dos tipos TEM e SHV entre isolados clínicos de Enterobacteriaceae

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          The extended-spectrum β-lactamase (ESBL)-producing bacteria have been isolated at increasing frequency worldwide. Expression of ESBL is often associated with multidrug resistance and dissemination by resistance plasmids. During a two-month period in 2000, 133 clinical isolates of enterobacterial strains were randomly collected from outpatients and inpatients at a university hospital in Turkey. The ESBL producing strains were determined by double-disk synergy (DDS) testing. Twenty ESBL producing strains (15%) including Escherichia coli (n = 9), Klebsiella pneumoniae (n = 7), Klebsiella oxytoca (n = 2) and Enterobacter aerogenes (n = 2) were detected and further analyzed for their resistance transfer features, plasmid profile and nature of the resistance genes. Plasmid transfer assays were performed using broth mating techniques. TEM- and SHV- genes were analyzed by polymerase chain reaction (PCR) and hybridization using specific probes. EcoRI restriction enzyme analyses of R plasmids were used in the detection of epidemic plasmids. Fourteen plasmid profiles (A, B1, B2, C1, and C2 to L) were obtained with EcoRI restriction enzyme analysis. Most of these plasmids were detected to carry both TEM- and SHV-derived genes by PCR, and confirmed by localizing each gene by hybridization assay. Epidemiological evidence indicated that there was an apparent horizontal dissemination of conjugative R plasmids among multidrug-resistant enterobacterial genera and species in this hospital

          Translated abstract

          O isolamento de bactérias produtoras de beta-lactamases de espectro expandido (ESBL) está aumentando no mundo todo. Freqüentemente, a expressão de ESBL está associada com resistência a múltiplas drogas e disseminação por plasmídios de resistência. Durante um período de dois meses em 2000, 133 isolados clínicos de cepas de enterobactérias foram obtidos aleatoriamente de pacientes internos e externos de um hospital universitário na Turquia. As cepas produtoras de ESBL foram identificadas pelo teste de sinergia em disco-duplo (DDS). Foram detectadas vinte cepas produtoras de ESBL, entre as quais Escherichia coli (n=9), Klebsiella pneumoniae (n=7), Klebsiella oxytoca (n=2) e Enterobacter aerogenes (n=2), que foram posteriormente analisadas quanto a suas características de transferência de resistência, perfil plasmidial e natureza dos genes de resistência. Os testes de transferência de plasmídios foram realizados empregando técnicas de conjugação em caldo. Os genes TEM e SHV foram analisados pela reação da polimerase em cadeia (PCR) e hibridização com sondas especificas. A detecção de plasmídios epidêmicos foi feita por análise dos plasmídios R com a enzima de restrição EcoRI. Através desta análise, foram obtidos catorze perfis plasmidiais (A, B1, B2, C1 e C2 até L).Observou-se pela PCR que a maioria dos plasmidios carregavam genes derivados de TEM e SHV, confirmados através da detecção dos genes pelos testes de hibridização. As evidencias epidemiológicas indicaram que havia uma aparente transferência horizontal dos plasmídios R conjugativos entre as enterobactérias multiresistentes neste hospital.

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          Most cited references 30

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          Multiple antibiotic-resistant Klebsiella and Escherichia coli in nursing homes.

          Infections caused by ceftazidime sodium-resistant gram-negative bacteria that harbor extended-spectrum beta-lactamases (ESBLs) are increasing in frequency in hospitals in the United States. To report a citywide nursing home-centered outbreak of infections caused by ESBL-producing gram-negative bacilli and to describe the clinical and molecular epidemiology of the outbreak. Hospital-based case-control study and a nursing home point-prevalence survey. Molecular epidemiological techniques were applied to resistant strains. A 400-bed tertiary care hospital and a community nursing home. Patients who were infected and/or colonized with ceftazidime-resistant Escherichia coli, Klebsiella pneumoniae, or both and controls who were admitted from nursing homes between November 1990 and July 1992. Clinical and epidemiological factors associated with colonization or infection by ceftazidime-resistant E coli or K pneumoniae; molecular genetic characteristics of plasmid-mediated ceftazidime resistance. Between November 1990 and October 1992, 55 hospital patients infected or colonized with ceftazidime-resistant E coli, K pneumoniae, or both were identified. Of the 35 admitted from 8 nursing homes, 31 harbored the resistant strain on admission. All strains were resistant to ceftazidime, gentamicin, and tobramycin; 96% were resistant to trimethoprim-sulfamethoxazole and 41% to ciprofloxacin hydrochloride. In a case-control study, 24 nursing home patients colonized with resistant strains on hospital admission were compared with 16 nursing home patients who were not colonized on hospital admission; independent risk factors for colonization included poor functional level, presence of a gastrostomy tube or decubitus ulcers, and prior receipt of ciprofloxacin and/or trimethoprim-sulfamethoxazole. In a nursing home point-prevalence survey, 18 of 39 patients were colonized with ceftazidime-resistant E coli; prior receipt of ciprofloxacin or trimethoprim-sulfamethoxazole and presence of a gastrostomy tube were independent predictors of resistance. Plasmid studies on isolates from 20 hospital and nursing home patients revealed that 17 had a common 54-kilobase plasmid, which conferred ceftazidime resistance via the ESBL TEM-10, and mediated resistance to trimethoprim-sulfamethoxazole, gentamicin, and tobramycin; all 20 isolates harbored this ESBL. Molecular fingerprinting showed 7 different strain types of resistant K pneumoniae and E coli distributed among the nursing homes. Nursing home patients may be an important reservoir of ESBL-containing multiple antibiotic-resistant E coli and K pneumoniae. Widespread dissemination of a predominant antibiotic resistance plasmid has occurred. Use of broad-spectrum oral antibiotics and probably poor infection control practices may facilitate spread of this plasmid-mediated resistance. Nursing homes should monitor and control antibiotic use and regularly survey antibiotic resistance patterns among pathogens.
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              Extended Broad-Spectrum  -Lactamases Conferring Transferable Resistance to Newer  -Lactam Agents in Enterobacteriaceae: Hospital Prevalence and Susceptibility Patterns


                Author and article information

                Brazilian Journal of Microbiology
                Braz. J. Microbiol.
                Sociedade Brasileira de Microbiologia (São Paulo, SP, Brazil )
                December 2008
                : 39
                : 4
                : 636-643
                Rize orgnameFaculty of Arts and Sciences orgdiv1Department of Biology
                Trabzon orgnameKaradeniz Technical University orgdiv1Faculty of Medicine orgdiv2Department of Microbiology and Clinical Microbiology Turkey
                S1517-83822008000400007 S1517-8382(08)03900407

                This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

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