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Dynamics of quinolone resistance in fecal Escherichia coli of finishing pigs after ciprofloxacin administration.

Huang K, Xu CW, Zeng B, Xia QQ, Zhang AY, Lei CW, Guan ZB, Cheng H, Wang HN - J. Vet. Med. Sci. (2014)

Bottom Line: The results showed that the minimal inhibitory concentration (MIC) for ciprofloxacin increased 16-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin administration for 3 days and decreased 256-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin withdrawal for 26 days.GyrA (S83L, D87N/ D87Y) and parC (S80I) substitutions were observed in all quinolone-resistant E. coli (QREC) clones with an MIC ≥8 µg/ml.This study provides scientific theoretical guidance for the rational use of antimicrobials and the control of bacterial resistance.

View Article: PubMed Central - PubMed

Affiliation: School of Life Science, Sichuan University, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-resources and Eco-environment, Ministry of Education, "985 Project" Science Innovative Platform for Resource and Environment Protection of Southwestern China, Chengdu, Sichuan 610064, P. R. China.

ABSTRACT
Escherichia coli resistance to quinolones has now become a serious issue in large-scale pig farms of China. It is necessary to study the dynamics of quinolone resistance in fecal Escherichia coli of pigs after antimicrobial administration. Here, we present the hypothesis that the emergence of resistance in pigs requires drug accumulation for 7 days or more. To test this hypothesis, 26 pigs (90 days old, about 30 kg) not fed any antimicrobial after weaning were selected and divided into 2 equal groups: the experimental (EP) group and control (CP) group. Pigs in the EP group were orally treated daily with 5 mg ciprofloxacin/kg of body weight for 30 days, and pigs in the CP group were fed a normal diet. Fresh feces were collected at 16 time points from day 0 to day 61. At each time point, ten E. coli clones were tested for susceptibility to quinolones and mutations of gyrA and parC. The results showed that the minimal inhibitory concentration (MIC) for ciprofloxacin increased 16-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin administration for 3 days and decreased 256-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin withdrawal for 26 days. GyrA (S83L, D87N/ D87Y) and parC (S80I) substitutions were observed in all quinolone-resistant E. coli (QREC) clones with an MIC ≥8 µg/ml. This study provides scientific theoretical guidance for the rational use of antimicrobials and the control of bacterial resistance.

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Growth profiles of E. coli clones (n=5) from before ciprofloxacinadministration (BS-E. coli, QSEC), after ciprofloxacin administration(R-E. coli, QREC) and after ciprofloxacin administration(AS-E. coli, QSEC).
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fig_003: Growth profiles of E. coli clones (n=5) from before ciprofloxacinadministration (BS-E. coli, QSEC), after ciprofloxacin administration(R-E. coli, QREC) and after ciprofloxacin administration(AS-E. coli, QSEC).

Mentions: Growth rates of E. coli clones: The E. coli clones weused to measure growth rates were quinolones susceptible E. coli (QSEC)from feces before ciprofloxacin administration (day 0) and after ciprofloxacin withdrawal(day 61); and the E. coli clones after ciprofloxacin administration (day26) were QREC clones. The QREC clones showed lower growth rates than QSEC clones (Fig. 3Fig. 3.


Dynamics of quinolone resistance in fecal Escherichia coli of finishing pigs after ciprofloxacin administration.

Huang K, Xu CW, Zeng B, Xia QQ, Zhang AY, Lei CW, Guan ZB, Cheng H, Wang HN - J. Vet. Med. Sci. (2014)

Growth profiles of E. coli clones (n=5) from before ciprofloxacinadministration (BS-E. coli, QSEC), after ciprofloxacin administration(R-E. coli, QREC) and after ciprofloxacin administration(AS-E. coli, QSEC).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4197147&req=5

fig_003: Growth profiles of E. coli clones (n=5) from before ciprofloxacinadministration (BS-E. coli, QSEC), after ciprofloxacin administration(R-E. coli, QREC) and after ciprofloxacin administration(AS-E. coli, QSEC).
Mentions: Growth rates of E. coli clones: The E. coli clones weused to measure growth rates were quinolones susceptible E. coli (QSEC)from feces before ciprofloxacin administration (day 0) and after ciprofloxacin withdrawal(day 61); and the E. coli clones after ciprofloxacin administration (day26) were QREC clones. The QREC clones showed lower growth rates than QSEC clones (Fig. 3Fig. 3.

Bottom Line: The results showed that the minimal inhibitory concentration (MIC) for ciprofloxacin increased 16-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin administration for 3 days and decreased 256-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin withdrawal for 26 days.GyrA (S83L, D87N/ D87Y) and parC (S80I) substitutions were observed in all quinolone-resistant E. coli (QREC) clones with an MIC ≥8 µg/ml.This study provides scientific theoretical guidance for the rational use of antimicrobials and the control of bacterial resistance.

View Article: PubMed Central - PubMed

Affiliation: School of Life Science, Sichuan University, Animal Disease Prevention and Food Safety Key Laboratory of Sichuan Province, Key Laboratory of Bio-resources and Eco-environment, Ministry of Education, "985 Project" Science Innovative Platform for Resource and Environment Protection of Southwestern China, Chengdu, Sichuan 610064, P. R. China.

ABSTRACT
Escherichia coli resistance to quinolones has now become a serious issue in large-scale pig farms of China. It is necessary to study the dynamics of quinolone resistance in fecal Escherichia coli of pigs after antimicrobial administration. Here, we present the hypothesis that the emergence of resistance in pigs requires drug accumulation for 7 days or more. To test this hypothesis, 26 pigs (90 days old, about 30 kg) not fed any antimicrobial after weaning were selected and divided into 2 equal groups: the experimental (EP) group and control (CP) group. Pigs in the EP group were orally treated daily with 5 mg ciprofloxacin/kg of body weight for 30 days, and pigs in the CP group were fed a normal diet. Fresh feces were collected at 16 time points from day 0 to day 61. At each time point, ten E. coli clones were tested for susceptibility to quinolones and mutations of gyrA and parC. The results showed that the minimal inhibitory concentration (MIC) for ciprofloxacin increased 16-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin administration for 3 days and decreased 256-fold compared with the initial MIC (0.5 µg/ml) after ciprofloxacin withdrawal for 26 days. GyrA (S83L, D87N/ D87Y) and parC (S80I) substitutions were observed in all quinolone-resistant E. coli (QREC) clones with an MIC ≥8 µg/ml. This study provides scientific theoretical guidance for the rational use of antimicrobials and the control of bacterial resistance.

Show MeSH
Related in: MedlinePlus