Increasing prevalence of extended-spectrum cephalosporin-resistant Escherichia coli in food animals and the diversity of CTX-M genotypes during 2003–2012

Rao, Lili; Lv, Luchao; Zeng, Zhenling; Chen, Sheng; He, Dongjian; Chen, Xiaojie; Wu, Congming; Wang, Yang; Yang, Tong; Wu, Peng; Liu, Yahong; Liu, Jian Hua

doi:10.1016/j.vetmic.2014.06.013

Cited by 99 publications

(89 citation statements)

References 33 publications

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“…From the evolution point of view, it is likely that the formation of hybrids is through homologous recombination between CTX-M-14 and CTX-M-15, driven by the evolutionary pressure favoring selection of expanded-spectrum cephalosporins. Epidemiological findings that the hybrid CTX-Ms are more commonly reported from E. coli strains in regions where the use of expandedspectrum cephalosporins is commonplace than in regions where expanded-spectrum cephalosporins are used less, support this hypothesis (21,22).…”

Section: Resultsmentioning

confidence: 93%

Residues Distal to the Active Site Contribute to Enhanced Catalytic Activity of Variant and Hybrid β-Lactamases Derived from CTX-M-14 and CTX-M-15

Chiou

Zeng

et al. 2015

Antimicrob Agents Chemother

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A variety of CTX-M-type extended-spectrum ␤-lactamases (ESBLs), including hybrid ones, have been reported in China that are uncommon elsewhere. To better characterize the substrate profiles and enzymatic mechanisms of these enzymes, we performed comparative kinetic analyses of both parental and hybrid CTX-M enzymes, including CTX-M-15, -132, -123, -64, -14 and -55, that are known to confer variable levels of ␤-lactam resistance in the host strains. All tested enzymes were susceptible to serine ␤-lactamase inhibitors, with sulbactam exhibiting the weakest inhibitory effects. CTX-M-55, which differs from CTX-M-15 by one substitution, A 77 V, displayed enhanced catalytic activity (k cat /K m ) against expanded-spectrum cephalosporins (ESCs). CTX-M-55 exhibits higher structure stability, most likely by forming hydrophobic interactions between A 77 V and various key residues in different helices, thereby stabilizing the core architecture of the helix cluster, and indirectly contributes to a more stable active site conformation, which in turn shows higher catalytic efficiency and is more tolerant to temperature change. Analyses of the hybrids and their parental prototypes showed that evolution from CTX-M-15 to CTX-M-132, CTX-M-123, and CTX-M-64, characterized by gradual enhancement of catalytic activity to ESCs, was attributed to introduction of different substitutions to amino acids distal to the active site of CTX-M-15. Similarly, the increased hydrolytic activities against cephalosporins and sensitivity to ␤-lactamase inhibitors, clavulanic acid and sulbactam, of CTX-M-64 were partly due to the amino acids that were different from CTX-M-14 and located at both the C and N termini of CTX-M-64. These data indicate that residues distal to the active site of CTX-Ms contributed to their enhanced catalytic activities to ESCs.T he rapid dissemination of CTX-M-type extended-spectrum ␤-lactamases (ESBLs) in Enterobacteriaceae poses a huge threat to both human and animal health. To date, more than 150 different CTX-M-type ESBLs have been identified (http://www .lahey.org/studies/other.asp#table1). Based on the genetic relatedness, CTX-Ms can be divided into six clusters, including CTX-M-1, -2, -8, -9, and -25 and the KLUC groups (1). More than 95% identity is often observed within the same cluster, whereas less than 90% identity is detectable between clusters (2). Several hybrids of the CTX-M-1 and -9 groups, namely, CTX-M-64, CTX-M-123, CTX-M-137, and CTX-M-132, have also been identified recently (3-5). Formation of these hybrid CTX-M enzymes was suggested to be the result of recombination between bla CTX-M-15 and bla CTX-M-14 , the two most dominant variants detectable worldwide (1, 6). However, the genetic environments of bla CTX-M-123 and bla CTX-M-64 were highly similar to that of bla CTX-M-55 identified in pHN1122-1, the second-most prevalent bla CTX-M variant in China (7). This suggests that recombination may take place between bla CTX-M-14 and bla CTX-M-55 , producing various hybrid enzymes. Interestingly, all three p...

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Section: Resultsmentioning

confidence: 93%

Residues Distal to the Active Site Contribute to Enhanced Catalytic Activity of Variant and Hybrid β-Lactamases Derived from CTX-M-14 and CTX-M-15

Chiou

Zeng

et al. 2015

Antimicrob Agents Chemother

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“…AHC4, carrying bla CTX-M-123 , and AHC46, carrying bla CTX-M-64 , were found in chicken samples submitted to a veterinary diagnostic center in Anhui Province, China, and the contexts of their bla CTX-M genes had already been partially characterized (4). JC2, from a chicken sample from Shandong Province, was identified as carrying bla CTX-M-15 in a previous study (14). LDH19 was from a urine sample collected in 2013 from a female patient at a community hospital in Guangzhou.…”

Section: Methodsmentioning

confidence: 92%

“…PCR with published primers (see Table S1 in the supplemental material) was used to amplify bla CTX-M-1 group and bla CTX-M-1/9/1 hybrid genes in LDH19 and to determine the spacer length in both isolates. Five more E. coli isolates carrying bla CTX-M-64 and 15 carrying bla CTX-M-123 were available from a set of isolates collected from animals in China in 2010-2012 (Table 1) (14). Multilocus sequence typing (MLST) was performed according to http://mlst.warwick.ac.uk.…”

Section: Methodsmentioning

confidence: 99%

bla _CTX-M-1/9/1 Hybrid Genes May Have Been Generated from bla _CTX-M-15 on an IncI2 Plasmid

Liu

et al. 2015

Antimicrob Agents Chemother

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“…CTX-M-55 first isolated from E. coli in Thailand [33] developed from one point mutation of CTX-M-15, leading to replacement of amino acid 80.In recent years, CTX-M-55 in E. coli was separated from food animals and pets in China [33][34][35][36][37], but was very rare in clinical isolates. Yu et al [10] first detected it in S. Typhimurium from the stool of a child in 2011.…”

Section: Discussionmentioning

confidence: 99%

Prevalence, resistance, and extended-spectrum beta-lactamases among Salmonella from patients in northeast China

Zhang¹,

Wang²,

Li³

et al. 2017

J Infect Dev Ctries

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Introduction: Salmonella is an important infection in Liaoning Province. Serotype and resistance levels are poorly studied. Knowledge of cephalosporin-resistant genes is needed to provide information to support the clinical diagnosis and to guide therapy. Methodology: A total of 172 isolates were collected from January 2009 to March 2014. Resistance to cephalosporin, fluoroquinolones, and other conventional first-line antibiotics was detected using the disk diffusion and agar dilution methods. The relatedness of isolates with the same serotype was analyzed by pulsed-field gel electrophoresis (PFGE). Genes encoding extended-spectrum β-lactamase enzymes (blaCTX-M, blaTEM, blaSHV, and blaOXA) were identified by polymerase chain reaction (PCR) and sequencing in cephalosporin-resistant strains. Results: S. Enteritidis, 1,4,[5],12:i:-, and S .Typhimurium were the most common serotypes. The resistance rate of Salmonella to conventional first-line antibiotics sulfamethoxazole-trimethoprim, tetracycline, chloramphenicol, and ampicillin was 21%,33%,37%, and 55%,respectively. To fluoroquinolones (gatixacin, levofloxacin, and ciprofloxacin), the resistance rates were 7%,18%, and 23%, respectively, whereas for extended-spectrum cephalosporins(ceftazidime, cefepime, and ceftriaxone), there sistance rates were 4%,8%, and 9%. In total, 14blaCTX-M, 14 blaTEM-1, and 1blaOXA-1 were found in 15 Salmonella isolates resistant to cephalosporin. No blaSHVwas detected. The blaCTX-M-55 gene was the most frequently encountered gene. The blaCTX-M-65 gene from S. Enteritidis is described for first time in Salmonella from humans. Results of PFGE indicated strong similarity among Salmonella isolates in Liaoning Province. Conclusions: Extended-spectrum cephalosporins are the first choice for the treatment of infection with Salmonella, but blaCTX-M-encoded resistance, including blaCTX-M-65, is present.

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Increasing prevalence of extended-spectrum cephalosporin-resistant Escherichia coli in food animals and the diversity of CTX-M genotypes during 2003–2012

Cited by 99 publications

References 33 publications

Residues Distal to the Active Site Contribute to Enhanced Catalytic Activity of Variant and Hybrid β-Lactamases Derived from CTX-M-14 and CTX-M-15

Residues Distal to the Active Site Contribute to Enhanced Catalytic Activity of Variant and Hybrid β-Lactamases Derived from CTX-M-14 and CTX-M-15

bla _CTX-M-1/9/1 Hybrid Genes May Have Been Generated from bla _CTX-M-15 on an IncI2 Plasmid

Prevalence, resistance, and extended-spectrum beta-lactamases among Salmonella from patients in northeast China

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Increasing prevalence of extended-spectrum cephalosporin-resistant Escherichia coli in food animals and the diversity of CTX-M genotypes during 2003–2012

Cited by 99 publications

References 33 publications

Residues Distal to the Active Site Contribute to Enhanced Catalytic Activity of Variant and Hybrid β-Lactamases Derived from CTX-M-14 and CTX-M-15

Residues Distal to the Active Site Contribute to Enhanced Catalytic Activity of Variant and Hybrid β-Lactamases Derived from CTX-M-14 and CTX-M-15

bla CTX-M-1/9/1 Hybrid Genes May Have Been Generated from bla CTX-M-15 on an IncI2 Plasmid

Prevalence, resistance, and extended-spectrum beta-lactamases among Salmonella from patients in northeast China

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bla _CTX-M-1/9/1 Hybrid Genes May Have Been Generated from bla _CTX-M-15 on an IncI2 Plasmid