The blaCTX-M gene independently enhances drug resistance level to ampicillin in clinical isolates of Klebsiella pneumoniae

Yang, Chen; Zhao, Junlong; Ding, Fengshu; Wang, Baoying; Zhang, Wenli; Gu, Jiarui; Huang, Ying; Fu, Yingmei; Zhang, Fengmin

doi:10.1038/ja.2012.44

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…45 While CTX-M and SHV β-lactamases have been linked to ampicillin resistance in Klebsiella pneumoniae clinical isolates, [46][47][48] their link to ampicillin resistance of E. coli has not been established. 49,50 In our study, as in other clinical studies, bla TEM was found to be the most common gene encoding β-lactamases followed by bla CTX-M and bla SHV. 5,[51][52][53][54] In the presence of both bla TEM and bla CTX-M , the MIC for ampicillin in E. coli clinical isolates was in range 32.0 to 256.0 µg/mL.…”

Section: Discussionsupporting

confidence: 85%

Escherichia coli from Human Wounds: Analysis of Resistance to β-Lactams and Expression of RND Efflux Pumps

Rihacek,

Kuthanova,

Splichal

et al. 2023

IDR

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Purpose Resistance of pathogenic strains of Escherichia coli to β-lactams, particularly to ampicillin, is on the rise and it is attributed to intrinsic and acquired mechanisms. One important factor contributing to resistance, together with primarily resistance mechanisms, is a mutation and/or an over-expression of the intrinsic efflux pumps in the resistance-nodulation-division (RND) superfamily. Among these efflux pumps, AcrA, AcrB, TolC, and AcrD play an important role in antimicrobial co-resistance, including resistance to β-lactams. Materials and Methods Twelve E. coli isolates obtained from patients’ wounds and the control strain of E. coli ATCC 25922 were analyzed. The phenotypic resistance of these isolates to selected β-lactams was assessed by determination of the minimal inhibitory concentration. Additionally, the prevalence of β-lactamase genes ( bla TEM , bla CTX-M , bla SHV , and bla AmpC ) was screened by PCR. Real-time qPCR was used to determine the expression of the selected efflux pumps acrA, acrB, tolC , and acrD and the repressor acrR after the exposure of E. coli to ampicillin. Results Phenotypic resistance to β-lactams was detected in seven isolates, mainly to ampicillin and piperacillin. This was corroborated by the presence of at least one acquired bla gene in each of these isolates. Although E. coli strains varied in the expression of RND-family efflux pumps after the ampicillin exposure, their gene expression indicated that these pumps did not play a major role in the phenotypic resistance to ampicillin. Conclusion Each E. coli isolate displayed unique characteristics, differing in minimum inhibitory concentration (MIC) values, prevalence of acquired blaTEM and blaCTX-M genes, and expression of the RND-family pumps. This together demonstrates that these clinical isolates employed distinct intrinsic or acquired resistance pathways for their defense against ampicillin. The prevalence and spread of ampicillin resistant E. coli has to be monitored and the search for ampicillin alternatives is needed.

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Section: Discussionsupporting

confidence: 85%

Escherichia coli from Human Wounds: Analysis of Resistance to β-Lactams and Expression of RND Efflux Pumps

Rihacek,

Kuthanova,

Splichal

et al. 2023

IDR

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“…Relevant studies and our work showed that bacterial CTX-M gene is associated with cefotaxime resistance [ 11 , 21 ]. CTX-M gene transfer experiments also confirmed that the CTX-M gene enables the bacteria to cefotaxime resistance [ 22 ].…”

Section: Discussionmentioning

confidence: 97%

“…Genomic DNA as templates were prepared using boiling pyrolysis method from clinical isolate s of K. pneumoniae . Specific PCR primers for genes bla SHV , bla TEM , bla CTX-M-1 and bla CTX-M-9 were determined in our previous study [ 9 , 11 ] listed in Table 1 . PCR reaction conditions were as follows: initial denaturation at 94 °C for 3 min, followed by 25 cycles of denaturation at 94 °C for 30 s, annealing for 30 s, and extension at 72 °C for 1 min, then extension at 72 °C for 5 min.…”

Section: Methodsmentioning

confidence: 99%

Synergistic effects of baicalein with cefotaxime against Klebsiella pneumoniae through inhibiting CTX-M-1 gene expression

Cai

Zhang

et al. 2016

BMC Microbiol

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BackgroundGeneration of extended- spectrum β- lactamases is one of the major mechanisms by which clinical Klebsiella pneumoniae develop resistance to antibiotics. Combined antibiotics prove to be a relatively effective method of controlling such resistant strains. Some of Chinese herbal active ingredients are known to have synergistic antibacterial effects. This study is aimed to investigate synergistic effects of Chinese herbal active ingredients with cefotaxime on the extended- spectrum β- lactamase positive strains of Klebsiella pneumoniae, and to analyze mechanism of synergistic action, providing experimental evidence for clinical application of antimicrobial drugs.ResultsFor total sixteen strains including fifteen strains of cefotaxime resistant K. pneumoniae and one extended- spectrum β- lactamase positive standard strain, the synergy rates of cefotaxime with baicalein, matrine, and clavulanic acid were 56.3 %, 0 %, and 100 %, respectively. The fractional inhibitory concentration index of combined baicalein and cefotaxime was correlated with the percentage decrease of cefotaxime MIC of all the strains (r = −0.78, p <0.01). In the group of synergy baicalein and cefotaxime, the transcribed mRNA level of CTX-M-1 after treatment of baicalein was decreased significantly (p <0.05). Moreover, the CTX-M-1 mRNA expression percentage inhibition (100 %, 5/5) was significantly higher than non- synergy group (25 %, 1/4) (p <0.05).ConclusionsOur study demonstrated that baicalein exhibited synergistic activity when combined with cefotaxime against some of extended- spectrum β- lactamases positive K. pneumoniae strains by inhibiting CTX-M-1 mRNA expression. However, no direct bactericidal or bacteriostatic activity was involved in the synergistic action. Baicalein seems to be a promising novel effective synergistic antimicrobial agent.Electronic supplementary materialThe online version of this article (doi:10.1186/s12866-016-0797-1) contains supplementary material, which is available to authorized users.

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Siderophore iucA of hypermucoviscous Klebsiella pneumoniae promotes liver damage in mice by inducing oxidative stress

Wu¹,

Chen²,

Wang³

et al. 2022

Biochemistry and Biophysics Reports

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The blaCTX-M gene independently enhances drug resistance level to ampicillin in clinical isolates of Klebsiella pneumoniae

Cited by 4 publications

References 13 publications

Escherichia coli from Human Wounds: Analysis of Resistance to β-Lactams and Expression of RND Efflux Pumps

Escherichia coli from Human Wounds: Analysis of Resistance to β-Lactams and Expression of RND Efflux Pumps

Synergistic effects of baicalein with cefotaxime against Klebsiella pneumoniae through inhibiting CTX-M-1 gene expression

Siderophore iucA of hypermucoviscous Klebsiella pneumoniae promotes liver damage in mice by inducing oxidative stress

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