Phenotypic and molecular characterization of CTX-M-14 extended-spectrum β-lactamase and plasmid-mediated ACT-like AmpC β-lactamase produced by Klebsiella pneumoniae isolates from chickens in Henan Province, China

Wu, Hua; Liu, B.-G.; Liu, J.-H.; Pan, Y.-S.; Yuan, Lili; Hu, Gong

doi:10.4238/2012.september.24.1

Cited by 13 publications

(9 citation statements)

References 25 publications

(21 reference statements)

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“…The susceptibility profile of K. pneumoniae strains revealed a high resistance to ampicillin, nalidixic acid, sulphonamides and tetracycline. These data corroborate the findings reported by Kim et al (2005) and Wu et al (2012), who demonstrated high levels of resistance to beta-lactams and tetracyclines. The results of the present study showed that 25% of the strains possessed multiple resistance (to three or more classes of antimicrobials).…”

Section: Discussionsupporting

confidence: 91%

Virulence and antimicrobial resistance ofKlebsiella pneumoniaeisolated from passerine and psittacine birds

et al. 2016

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Klebsiella pneumoniae is considered one of the most important Gram-negative opportunistic pathogens. The contact between humans and birds poses health risks to both. The aim of this study was to investigate the resistance and virulence of K. pneumoniae isolates from psittacines and passerines, seized from illegal trade in Brazil. We analysed 32 strains isolated from birds of the orders Psittaciformes and Passeriformes by polymerase chain reaction (PCR) for virulence factor genes. Antibiotic resistance was assessed by disk diffusion assay and PCR. The results indicated that fimH (100%), uge (96.8%), kfu (81.2%) and irp-2 (68.7%) were the most common virulence genes, followed by kpn (46.8%), K2 (43.7%), mrkD (34.3%) and iroN (15.6%). The combination of virulence genes resulted in a great diversity of genotypes and the heterogeneity of the strains is also confirmed in the analysis by amplified fragment length polymorphism. The susceptibility profiles of the K. pneumoniae showed 25% of multiple antibiotic resistance strains. We identified seven strains that presented non-extended spectrum beta lactamase blaSHV variants SHV-1 and SHV-11 and one strain positive to the blaTEM-1 gene. Plasmid-mediated quinolone resistance was present in 10 strains (10/32). The data obtained in this study reveal the pathogenic potential of this pathogen and highlight the need for surveillance and monitoring.

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Section: Discussionsupporting

confidence: 91%

Virulence and antimicrobial resistance ofKlebsiella pneumoniaeisolated from passerine and psittacine birds

et al. 2016

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“…E. coli strain LDH19 carrying bla CTX-M-132 was obtained from a urine sample from a female patient at a community hospital in Guangzhou, China. Clinical E. coli strains carrying bla CTX-M-14 and bla CTX-M-15 described in our previous study were also used in this study (10,11). The bla CTX-M genes were amplified by PCR using primers listed in Table 1 and cloned into the pET28b vector (Novagen).…”

Section: Methodsmentioning

confidence: 99%

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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“…However, antimicrobial-resistant K . pneumoniae strains have been isolated from marketed fresh vegetables [ 8 ], shrimp in international trade [ 9 ], and farm-raised chicken [ 10 ]. A recent report showed that foodborne K .…”

Section: Introductionmentioning

confidence: 99%

Frequency, Antimicrobial Resistance and Genetic Diversity of Klebsiella pneumoniae in Food Samples

et al. 2016

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This study aimed to assess the frequency of Klebsiella pneumoniae in food samples and to detect antibiotic resistance phenotypes, antimicrobial resistance genes and the molecular subtypes of the recovered isolates. A total of 998 food samples were collected, and 99 (9.9%) K. pneumoniae strains were isolated; the frequencies were 8.2% (4/49) in fresh raw seafood, 13.8% (26/188) in fresh raw chicken, 11.4% (34/297) in frozen raw food and 7.5% (35/464) in cooked food samples. Antimicrobial resistance was observed against 16 antimicrobials. The highest resistance rate was observed for ampicillin (92.3%), followed by tetracycline (31.3%), trimethoprim-sulfamethoxazole (18.2%), and chloramphenicol (10.1%). Two K. pneumoniae strains were identified as extended-spectrum β-lactamase (ESBL)–one strain had three beta-lactamases genes (blaSHV, blaCTX-M-1, and blaCTX-M-10) and one had only the blaSHV gene. Nineteen multidrug-resistant (MDR) strains were detected; the percentage of MDR strains in fresh raw chicken samples was significantly higher than in other sample types (P<0.05). Six of the 18 trimethoprim-sulfamethoxazole-resistant strains carried the folate pathway inhibitor gene (dhfr). Four isolates were screened by PCR for quinolone resistance genes; aac(6’)-Ib-cr, qnrB, qnrA and qnrS were detected. In addition, gyrA gene mutations such as T247A (Ser83Ile), C248T (Ser83Phe), and A260C (Asp87Ala) and a parC C240T (Ser80Ile) mutation were identified. Five isolates were screened for aminoglycosides resistance genes; aacA4, aacC2, and aadA1 were detected. Pulsed-field gel electrophoresis-based subtyping identified 91 different patterns. Our results indicate that food, especially fresh raw chicken, is a reservoir of antimicrobial-resistant K. pneumoniae, and the potential health risks posed by such strains should not be underestimated. Our results demonstrated high prevalence, antibiotic resistance rate and genetic diversity of K. pneumoniae in food in China. Improved control and prevention strategies are urgently needed.

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Phenotypic and molecular characterization of CTX-M-14 extended-spectrum β-lactamase and plasmid-mediated ACT-like AmpC β-lactamase produced by Klebsiella pneumoniae isolates from chickens in Henan Province, China

Cited by 13 publications

References 25 publications

Virulence and antimicrobial resistance ofKlebsiella pneumoniaeisolated from passerine and psittacine birds

Virulence and antimicrobial resistance ofKlebsiella pneumoniaeisolated from passerine and psittacine birds

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

Frequency, Antimicrobial Resistance and Genetic Diversity of Klebsiella pneumoniae in Food Samples

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