Caracterização de beta-lactamases de espectro ampliado (ESBLs), genes de resistência aos antimicrobianos e conteúdo plasmidial em cepas de Escherichia coli e Salmonella spp. não tifóides isoladas do ambiente hospitalar e da comunidade / Characterization of extended spectrum Beta-lactamase (ESBLs), antimicrobial resistance genes, and plasmid content in Escherichia coli and Salmonella spp. isolates recovered from hospital and community

Enterobactérias produtoras de ESBLs são descritas tanto no ambiente hospitalar quanto na comunidade em todo o mundo. No Brasil, esses microrganismos também têm emergido como uma causa importante de infecções, sendo as enzimas CTX-M as prevalentes. O objetivo deste estudo foi analisar diferentes aspectos genotípicos relacionados à expressão da resistência aos antimicrobianos em cepas Escherichia coli e de Salmonella spp, tais como: a diversidade de ESBLs, os genes de resistência aos antimicrobianos e o conteúdo plasmidial. Os aspectos epidemiológicos das cepas produtoras de ESBLs também foram investigados. Foram estudadas 88 cepas de enterobactérias, sendo 43 E. coli e 45 cepas de Salmonella spp., de origem hospitalar e da comunidade (principalmente alimentos), isoladas na cidade do Rio de Janeiro. A expressão de ESBL foi observada em sete cepas de E. coli (7/43, 16,3%) e em uma cepa de Salmonella Typhimurium (1/45, 2,3%) e as enzimas foram identificadas como variantes de CTX-M e SHV-5, respectivamente. Entre as cepas de E. coli, a enzima CTX-M-2 foi a mais frequente (n = 4), sendo detectada em cepas isoladas de swab retal de pacientes hospitalizados, enquanto as enzimas CTX-M-59 (uma variante de CTX-M) (n = 1) e CTX-M-9 (n = 2) foram identificadas em cepas isoladas a partir de espécimes clínicos. Salmonella Typhimurium produtora de SHV-5 foi isolada do ambiente hospitalar (fórmula infantil). As cepas de E. coli produtoras das enzimas CTX-M pertenceram a grupos filogenéticos (A, B1, D) e STs (ST34, ST69, ST101) diferentes, sendo os genes blaCTX-M identificados em plasmídeos com tipo de replicon IncA/C de cerca de 150 kb (blaCTX-M-2, blaCTX-M-9, blaCTX-M-59) ou 80 kb (blaCTX-M-2)...

ESBL-producing Enterobacteriaceae have been described in hospitals and in the community worldwide. In Brazil, ESBL-producing Enterobacteriaceae have also emerged as an important cause of infections, being CTX-M enzymes the most prevalent ESBLs. The objective of this study was to analyze different genotypic aspects related to expression of antimicrobial resistance in isolates of Escherichia coli and Salmonella spp., such as: diversity of ESBLs, antibiotic resistance genes and plasmid content. Epidemiological features of ESBL-producing isolates were also investigated. We studied 88 isolates of enterobacteria, 43 E. coli and 45 Salmonella serotypes of hospital and community (mainly food) origin, isolated in the city of Rio de Janeiro. ESBL expression was observed in seven E. coli isolates (7/43; 16,3%) and in one Salmonella Typhimurium (1/45; 2,3%) and the enzymes identified as CTX-M variants and SHV-5, respectively. Among the E. coli isolates, CTX-M-2 was the most frequent (n=4), being detected in isolates recovered from rectal swabs of hospitalized patients, whereas CTX-M-59 (a CTX-M-2-variant) (n=1) and CTX-M-9 (n=2) were identified in E. coli isolated from clinical specimens. SHV-5-producing S. Typhimurium was isolated from the hospital environment (infant formula). CTX-M-producing E. coli belonged to different phylogenetic groups (A, B1, D) and STs (ST34, ST69, ST101), being blaCTX-M genes were identified in IncA/C plasmids of approximately 150 kb (blaCTX-M-2, blaCTX-M-9, blaCTX-M-59) or 80 kb (blaCTX-M-2)...

CTX-M-9 group extended-spectrum β-lactamases in neonatal stool isolates: Emergence in India.

The study reports for the first time the identification of CTX-M-14-like and CTX-M-27-like extended-spectrum β-lactamases (ESBLs) belonging to the CTX-M-9 group in Klebsiella pneumoniae and Escherichia coli isolated from the neonatal stool in India. The plasmid carrying the blaCTX-M-9 group in both the isolates was transferable. Till date, no other CTX-M group, except the CTX-M-1 group, has been reported from India. A total of 77% of the neonates had ESBL-producing K. pneumoniae or E. coli in their stool, and blaCTX-M-15 was the predominant ESBL gene. Although the CTX-M-9 group was found in the stool and did not cause infection, the detection of the CTX-M-9 group might be a prelude to future infections.

Genotype distribution of extended-spectrum and AmpC ?-lactamases produced by Escherichia coli and Klebsiella pneumoniae in 10 teaching hospitals of China / 中国感染与化疗杂志

Objective To investigate the genotype distribution of extended-spectrum?-lactamases(ESBLs) and AmpC?-lacta- mases produced by Escherichia coli and Klebsiella pneumoniae in 10 teaching hospitals of China.Methods 90 clinical strains of E.coli and 61 strains of K.pneumoniae isolated in 2003 and confirmed to produce ESBLs were collected from 10 teaching hos- pitals in China.Analytical isoelectric focusing was used to measure the pI of the?-lactamases.Conjugation experiment was used to study the transfer of cefoxitin resistance.Plasmid-mediated AmpC enzyme genes were amplified and sequenced by multiplex polymerase chain reaction (MPCR).Results The prevalence of ESBL-producing E.coli and K.pneumoniae was about 50% in Wuhan,Nanjing and Jinan.The prevalence of ESBL-producing E.coli was lower than K.pneumoniae in Beijing.However,in other hospitals the prevalence of ESBL-producing E.coli was a little higher than K.pneumoniae.About 24.4% of ESBL-pro- ducing E.coli isolates and 19.4% of ESBL-producing K.pneumoniae isolates were resistant to cefoxitin.Cefoxitin-resistant i solate was identified in all hospitals except Shenyang.Major genotype of ESBL-producing isolates was CTX-M.The CTX-M-9 group was the most common group,followed by CTX-M-1.More K.pneumoniae isolates produced both ESBLs and AmpC en- zyme than E.coli.The genotype was CTX-M/DHA-1.The PCR results of 3 transconjugants producing both ESBLs and AmpC enzyme were the same as their donor isolates.Conclusions The genotype of ESBL-producing isolates is mainly CTX-M-9 group in these teaching hospitals.More K.pneumoniae isolates produced both ESBLs and AmpC enzyme than E.coli.Most of these isolates are due to geno type CTX-M/DHA-1,which can spread through plasmid.

Emergence of CTX-M-9 Extended-Spectrum beta-Lactamase-Producing Enterobacter cloacae Isolates / 대한임상미생물학회지

BACKGROUND: The aim of this study is to assess the prevalence and to investigate the molecular epidemiology of Ambler class A extended-spectrum beta-lactamase (ESBL)-producing Enterobacter cloacae isolates in a university hospital in Busan, Korea. METHODS: Non-duplicated clinical isolates of E.cloacae from patients admitted in Kosin University Gospel Hospital were collected during the period from January through September, 2003. ESBL-production was examined by the double-disk synergy test (DDST) and the transferability of cefotaxime-resistance by conjugation. MICs of beta-lactam antibiotics were determined by the agar dilution method and Ambler class A ESBL genes were searched by PCR amplification. Enterobacterial repetitive intergenic consensus (ERIC) PCR was performed to investigate epidemiological relationships among bla CTX-M-9 gene-carrying E.cloacae isolates. RESULTS: Antimicrobial resistance rates of E.cloacae isolates (n=148) to ceftazidime, cefotaxime, and aztreonam were 50.0%, 29.6%, and 48.0%, respectively. Among 50 E.cloacae isolates intermediate or resistant to more than one expanded-spectrum beta-lactam agent, 41 (27.7%) showed positive results in DDST; of these 41 isolates, 1 was found to carry bla TEM-52 gene, 16 carried bla SHV-12 gene, 4 bla CTX-M-9 gene, and 19 both bla SHV-12 and bla CTX-M-9 genes. The 23 E.cloacae isolates carrying bla CTX-M-9 gene showed 9 different profiles by ERIC PCR. CONCLUSION: ESBL-producing E.cloacae was not uncommon in a university hospital in Busan, Korea. The commonest types of ESBLs produced by E.cloacae isolates were SHV-12 and CTX-M-9. CTX-M-9 ESBL-producing E.cloacae isolates showed diverse ERIC-PCR profiles, indicating that they were not originated from a common source.

Prevalence of CTX-M Extended-spectrum Beta-lactamases in Clinical Isolates of Enterobacteriaceae in Korea

The evolution and dissemination of extended-spectrum beta-lactamases (ESBL) have compromised the clinical use of third-generation cephalosporins worldwide. Although most ESBLs belong to the TEM and SHV beta-lactamase families, the members of CTX-M, a novel ESBL family, are increasing worldwide in Gram-negative bacteria. We examined the prevalence of CTX-M ESBL in clinical isolates of the family Enterobacteriaceae collected from three university hospitals located in three different cities in Korea. Among a total of 603 isolates collected, 163 isolates (27.0%) revealed > or =2 microgram/ ml of MIC against cefotaxime, and 93 isolates (15.4%) produced ESBL confirmed by the double disk synergy test. Among 93 ESBL-producing isolates, blaCTX-M genes were detected in 41 isolates by PCR method and they included 1 isolate of C. freundii, 3 of E. aerogenes, 2 of E. cloacae, 17 of E. coli, 9 of K. pneumoniae, and 9 of S. marcescens. Thus, the overall prevalence of CTX-M ESBL-producing isolates among the family Enterobacteriaceae was 6.8% (41 of 603 isolates) and the proportion of CTX-M-producers among the ESBL-producing isolates was 44.1% (41 of 93 isolates). Further determination of the blaCTX-M subtype by nucleotide sequencing revealed blaCTX-M-3 in 17, blaCTX-M-15 in 11, blaCTX-M-14 in 9, and blaCTX-M-9 in 4 isolates. To our knowledge, this is the first report on the dissemination of CTX-M ESBL among clinical isolates of the family Enterobacteriaceae in Korea.

Prevalence of CTX-M Extended-spectrum Beta-lactamases in Clinical Isolates of Enterobacteriaceae in Korea

The evolution and dissemination of extended-spectrum beta-lactamases (ESBL) have compromised the clinical use of third-generation cephalosporins worldwide. Although most ESBLs belong to the TEM and SHV beta-lactamase families, the members of CTX-M, a novel ESBL family, are increasing worldwide in Gram-negative bacteria. We examined the prevalence of CTX-M ESBL in clinical isolates of the family Enterobacteriaceae collected from three university hospitals located in three different cities in Korea. Among a total of 603 isolates collected, 163 isolates (27.0%) revealed > or =2 microgram/ ml of MIC against cefotaxime, and 93 isolates (15.4%) produced ESBL confirmed by the double disk synergy test. Among 93 ESBL-producing isolates, blaCTX-M genes were detected in 41 isolates by PCR method and they included 1 isolate of C. freundii, 3 of E. aerogenes, 2 of E. cloacae, 17 of E. coli, 9 of K. pneumoniae, and 9 of S. marcescens. Thus, the overall prevalence of CTX-M ESBL-producing isolates among the family Enterobacteriaceae was 6.8% (41 of 603 isolates) and the proportion of CTX-M-producers among the ESBL-producing isolates was 44.1% (41 of 93 isolates). Further determination of the blaCTX-M subtype by nucleotide sequencing revealed blaCTX-M-3 in 17, blaCTX-M-15 in 11, blaCTX-M-14 in 9, and blaCTX-M-9 in 4 isolates. To our knowledge, this is the first report on the dissemination of CTX-M ESBL among clinical isolates of the family Enterobacteriaceae in Korea.