Rapid and simple detection of bla
            CTX−M genes by multiplex PCR assay

Xu, Li; Ensor, V. M.; Gossain, Savita; Nye, K.; Hawkey, Peter M.

doi:10.1099/jmm.0.46160-0

Cited by 111 publications

(77 citation statements)

References 27 publications

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“…Also, other studies showed the dissemination of CTX-M8 gene in Iran are higher than other parts of the world (34) On the other hand, in this study, the frequency of CTX-M-9 in isolates was less than Germany, America, Canada (ranged 38.5%-58.5%) (35,36).…”

Section: Discussioncontrasting

confidence: 42%

Dissemination of CTX-M-Type Beta-lactamase Among Clinical Isolates of Enterobacteriaceae in Markazi Province, Iran

Safari

Shojapour

Akbari

et al. 2013

Jundishapur J Microbiol

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Background: Organisms producing CTX-M-lactamases are known as the source of resistance to Oxyiminocephalosporins such as Eeftriaxone and Ceftazidime. However, the laboratory detection of these strains is not well defined. Objectives: The aim of this study was to determine the presence and prevalence of known CTX-M-beta-beta-lactamase genes in clinical isolates of Enterobacteriaceae from Arak educational hospitals, Iran. Materials and Methods: During a 10-month period (May to February 2010), 350 randomly Enterobacteriaceae isolates were obtained from the clinical laboratories of different hospitals of Arak University of Medical Sciences, Iran. Antibiotic susceptibility was tested by CLSI disk diffusion and extended spectrum beta-lactamase (ESBL) confirmatory tests. Minimum Inhibitory Concentration (MICs) was determined by broth micro dilution. All of the ESBL-producing isolates were examined by PCR to detect the presence of bla CTX-M genes. Results: In phenotypic confirmatory test, 154 (44%) out of 350 clinical isolates were ESBL positive. Using molecular assay, 154 strains potentially producing extended-spectrum-beta -lactamases were examined for the presence of CTX-M enzymes. 92.2% isolates CTX-M -1, 28.5% isolates CTX-M-2, 17.5% isolates CTX-M-8, and 38.3% isolates CTX-M-9 genes detected by PCR. Conclusions:The levels of resistance to Ceftazidime were remarkably variable among CTX-Mproducers. This study provides further evidences of the global dissemination of CTX-M type ESBLs and emphasized on the need for their epidemiological monitoring.

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Section: Discussioncontrasting

confidence: 42%

Dissemination of CTX-M-Type Beta-lactamase Among Clinical Isolates of Enterobacteriaceae in Markazi Province, Iran

Safari

Shojapour

Akbari

et al. 2013

Jundishapur J Microbiol

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“…All of the Salmonella isolates were screened by PCR for transferable PMQR-encoding genes, including qnrA, qnrB, qnrC, qnrD, qnrS, oqxAB, aac-(6=)-Ib, and qepA, as previously described (11,12). A multiplex PCR was used to screen for bla CTX-M in all of the ESBL-producing isolates (23). Another multiplex PCR method was applied to screen for plasmid-mediated AmpC-encoding genes in clavulanic acid-resistant isolates (24).…”

Section: Methodsmentioning

confidence: 99%

Emergence and Diversity of Salmonella enterica Serovar Indiana Isolates with Concurrent Resistance to Ciprofloxacin and Cefotaxime from Patients and Food-Producing Animals in China

Bai

Zhao

Gan

et al. 2016

Antimicrob Agents Chemother

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e Salmonellosis is a major global foodborne infection, and strains that are resistant to a great variety of antibiotics have become a major public health concern. The aim of this study was to identify genes conferring resistance to fluoroquinolones and extendedspectrum ␤-lactams in nontyphoidal Salmonella (NTS) from patients and food-producing animals in China. In total, 133 and 21 NTS isolates from animals and humans, respectively, exhibiting concurrent resistance to ciprofloxacin and cefotaxime were cultured independently from 2009 to ϳ2013. All of the isolates were identified, serotyped, and subjected to antimicrobial susceptibility testing. Importantly, the isolates with concurrent resistance to ciprofloxacin and cefotaxime all were confirmed as S. enterica serovar Indiana. The presence of fluoroquinolone resistance genes and extended-spectrum ␤-lactamases (ESBLs) was established by PCR and DNA sequencing. The occurrence and diversity of different genes conferring fluoroquinolone resistance [qepA, oqxAB, and aac(6=)-Ib-cr] with mutations in topoisomerase-encoding genes (gyrA and parC) and several ESBLs (including CTX-M-65, CTX-M-27, CTX-M-15, CTX-M-14, and CTX-M-14/CTX-M-15) were noteworthy. Genes located on mobile genetic elements were identified by conjugation and transformation. Pulsed-field gel electrophoresis, used to determine the genetic relationships between these isolates, generated 91 pulsotypes from 133 chicken isolates and 17 pulsotypes from the 21 clinical isolates that showed considerable diversity. Analysis of the pulsotypes obtained with the isolates showed some clones appeared to have existed for several years and had been disseminating between humans and food-producing animals. This study highlights the emergence of ciprofloxacin-and cefotaxime-resistant S. enterica serovar Indiana, posing a threat to public health.

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“…Detection of β-lactamase genes: β-Lactamase genes were detected by PCR and direct DNA sequencing according to a method described in previous studies [17,25,38].…”

Section: Methodsmentioning

confidence: 99%

Contribution of the AcrAB-TolC Efflux Pump to High-Level Fluoroquinolone Resistance in <i>Escherichia coli</i> Isolated from Dogs and Humans

Sato

Yokota

Okubo

et al. 2013

The Journal of Veterinary Medical Science

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ABSTRACT. Fluoroquinolone resistance is mainly caused by mutations in quinolone resistance-determining regions of DNA gyrase and topoisomerase IV in Escherichia coli. The AcrAB-TolC efflux pump contributes to resistance against fluoroquinolone and other antimicrobials. In this study, we investigated a high-level mechanism of fluoroquinolone resistance in E. coli that was isolated from human clinical samples and canine fecal samples. E. coli strains with high levels of fluoroquinolone resistance have been found to be frequently resistant to cephalosporins. Strains with high-level fluoroquinolone resistance exhibited lower intracellular enrofloxacin (ENR) concentrations, higher expression of AcrA, and a greater reduction in the fluoroquinolone minimum inhibitory concentration for treatment with an efflux pump inhibitor. The frequency of strains with enhanced ENR resistance selection and the survival rate of E. coli in the presence of ENR in vitro were correlated well with AcrA protein expression levels in the parental strains. These results suggest that AcrAB-TolC efflux pump over-expression is related to high-level fluoroquinolone resistance and the selection of strains with enhanced fluoroquinolone resistance. Antimicrobials that are intended for human use are also used on companion animals. Their excessive and inappropriate administration in animals leads to the generation and spread of antimicrobial-resistant bacteria, which in veterinary medicine represent a potential hazard to human health [1,26,33,36]. Companion animals live in close proximity to humans and receive medical treatment more frequently than food-producing animals [23]. Platell et al. reported that some fluoroquinolone-resistant Escherichia coli isolates that were derived from companion animals (i.e., dogs and cats) were very similar to the ones found in humans [27].Fluoroquinolones are widely used to treat various bacterial infections in humans and companion animals. E. coli infections, especially urinary tract infections, are frequently treated with fluoroquinolones. Thus, fluoroquinolone resistance has increased among clinical isolates of humans and companion animals [7,24]. Previous studies reported that extended-spectrum β-lactamase (ESBL)-producing E. coli and Klebsiella pneumoniae are frequently resistant to fluoroquinolone [20,30,32]. Cephalosporins and fluoroquinolones are among the most important antimicrobials that are used on humans and animals, mainly because of their broad-spectrum effectiveness against both gram-positive and gram-negative bacteria. Therefore, the appearance of fluoroquinolone-and/ or cephalosporin-resistant bacteria is a serious problem in clinical medicine.Fluoroquinolone resistance mechanisms are mainly based on chromosomal mutations in the quinolone resistancedetermining regions (QRDRs) of gyrA and gyrB, which encode DNA gyrase subunits, and parC and pare, which encode topoisomerase IV subunits [2,8,11,37]. Resistance to nalidixic acid (NAL) and slightly decreased susceptibility to fluoroquinolones is attribute...

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Rapid and simple detection of bla CTX−M genes by multiplex PCR assay

Cited by 111 publications

References 27 publications

Dissemination of CTX-M-Type Beta-lactamase Among Clinical Isolates of Enterobacteriaceae in Markazi Province, Iran

Dissemination of CTX-M-Type Beta-lactamase Among Clinical Isolates of Enterobacteriaceae in Markazi Province, Iran

Emergence and Diversity of Salmonella enterica Serovar Indiana Isolates with Concurrent Resistance to Ciprofloxacin and Cefotaxime from Patients and Food-Producing Animals in China

Contribution of the AcrAB-TolC Efflux Pump to High-Level Fluoroquinolone Resistance in <i>Escherichia coli</i> Isolated from Dogs and Humans

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