Intracellular concentrations of enrofloxacin in quinolone-resistant Salmonella enterica subspecies enterica serovar Choleraesuis

Usui, Masaru; Uchiyama, Mitsuru; Iwanaka, Mari; Nagai, Hidetaka; Yamamoto, Yasutake; Asai, Tetsuo

doi:10.1016/j.ijantimicag.2009.07.009

Cited by 9 publications

(16 citation statements)

References 16 publications

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“…Consistent with this, the frequency of strains with enhanced fluoroquinolone resistance was higher for susceptible isolates of Salmonella enterica serovar Choleraesuis with low intracellular ENR concentrations [34]. In this study, strains that exhibited higher AcrA expression showed higher ENR MICs, and we observed a correlation between the levels of AcrA expression, survival in ENR, and the frequency of QRDR mutations (Table 2).…”

Section: Discussionsupporting

confidence: 87%

“…Accumulation assay: The intracellular ENR concentration was assayed using a fluorometric uptake assay [34] with ENR at a final concentration of 15 µg/ml and carbonyl cyanide m-chlorophenylhydrazone (CCCP, Sigma-Aldrich) at a final concentration of 150 µM. The data represent the mean value ± standard errors (SE) that were calculated from 3 independent experiments.…”

Section: Methodsmentioning

confidence: 99%

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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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Section: Discussionsupporting

confidence: 87%

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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“…The spread of resistant determinant genes that are clonally disseminated and horizontally transferred was also observed in β-lactam penicillins (ampicillin, amoxicillin-clavulanic acid, carbenicillin), to which over 80% of the isolates showed resistance, except amocxicillin-clavulanic acid, to which the isolates did not have any resistance. This is an indication of the existence of blaPSE1, blaTEM, and oxa1 in the group of blaCMY-2 that are plasmid oriented (Table 3) [56,57]. This is an indication for the presence of plasmid-mediated β-lactamases including TEM-type penicillinase, inhibitor-resistant TEM (IRT) β-lactamase, and oxacillinase-1 (OXA-1) β-lactamase [57].…”

Section: Discussionmentioning

confidence: 99%

Antimicrobial profile of Salmonella enterica serotype Choleraesuis from free-range swine in Kakamega fish market, western Kenya

Onyango

Ndeda

Wandili

et al. 2014

J Infect Dev Ctries

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Introduction: Salmonella enterica subspecies enterica serovar Choleraesuis is a host-adapted, facultative, intracellular pathogen that causes swine paratyphoid. Its antimicrobial resistance presents a challenge to feed manufacturing industries. However, stopping antibiotics in animal feed would have economic implications for the industry. Methodology: Conventional microbial methods for isolation and identification of S. Choleraesuis were employed. The isolates were subjected to screening against 17 antimicrobial agents and genotyping of resistance markers by PCR. The data were then analyzed and presented in percentages. Results: Phenotypically, 43 out of 95 isolates showed multidrug resistance. Among the 17 antibiotics tested, resistance was observed as follows: sulphonamides (45

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“…Several researchers have reported that enhancement of efflux pumps contributed to the emergence of fluoroquinolone resistance in Salmonella [23,24]. The enhancement of efflux pumps as well as decreased membrane permeability has been observed in laboratory-derived mutants of Salmonella [3,4,6,11].…”

mentioning

confidence: 99%

“…The amounts of intracellular enrofloxacin were measured by a fluorometric uptake assay according to the method of Piddock et al [18] as described previously [24]. To investigate the effects of the efflux pump inhibitor on the concentration of intracellular enrofloxacin, the experiment was also carried out in the presence of CCCP (final concentration 100 M) [21].…”

mentioning

confidence: 99%

Contribution of Enhanced Efflux to Reduced Susceptibility of Salmonella enterica Serovar Choleraesuis to Fluoroquinolone and Other Antimicrobials

Usui

Uchiyama

Baba

et al. 2011

The Journal of Veterinary Medical Science

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ABSTRACT. We examined antimicrobial susceptibility and efflux systems in laboratory-derived mutants of Salmonella enterica serovar Choleraesuis selected by culture on fluoroquinolone-containing plates. The mutants exhibited decreased susceptibilities to quinolones and several other antimicrobials. Mutations in the gyrA gene were not always found in the mutants. Accumulation assays revealed that intracellular enrofloxacin concentrations were significantly lower in the mutants compared with parent isolates. Increased expression of acrB mRNA can explain the decreased susceptibilities to several antimicrobials but not in the case of carbonyl cyanide m-chlorophenylhydrazone (CCCP). Decreased susceptibility to CCCP may result from the increased expression of emrA mRNA. These results suggest that the enhancement of multiple efflux pumps is responsible for decreased susceptibilities to several antimicrobials in the laboratoryderived mutants.

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Intracellular concentrations of enrofloxacin in quinolone-resistant Salmonella enterica subspecies enterica serovar Choleraesuis

Cited by 9 publications

References 16 publications

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

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

Antimicrobial profile of Salmonella enterica serotype Choleraesuis from free-range swine in Kakamega fish market, western Kenya

Contribution of Enhanced Efflux to Reduced Susceptibility of Salmonella enterica Serovar Choleraesuis to Fluoroquinolone and Other Antimicrobials

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