Extensive dissemination of CTX-M-producing Escherichia coli with multidrug resistance to 'critically important' antibiotics among food animals in Hong Kong, 2008-10.
ABSTRACT To assess the occurrence of faecal carriage of Escherichia coli with resistance to 'critically important' antibiotics in various animals.
Rectal or cloacal swabs were obtained weekly from cattle, pigs, chickens, cats, dogs and wild rodents over a 2 year period. Plain and antibiotic-containing medium was used for bacterial isolation. Selected isolates were characterized by molecular methods.
In total, 2106 faecal specimens from 398 cats, 460 chickens, 368 dogs, 210 cattle, 214 pigs and 456 rodents were cultured. The faecal carriage rate of extended-spectrum β-lactamase (ESBL)-producing E. coli was highest in pigs (63.6%, 136/214) and lowest in rodents (4.2%, 19/456). The faecal ESBL-producing E. coli carriage rate for food-producing animals (53.6%, 474/884) was significantly higher than that for cats/dogs (14.0%, 107/766; P<0.01) and wild rodents (4.2%, 19/456; P<0.01). ESBL-producing isolates from food animals often (33%-81%) had multidrug (≥4) resistance to amikacin, chloramphenicol, ciprofloxacin, co-trimoxazole, gentamicin, nalidixic acid, netilmicin, nitrofurantoin and tetracycline. Most (91.2%) of the ESBL-producing isolates had CTX-M-type enzymes. A total of 10 alleles (3, 13, 14, 15, 24, 27, 28, 55, 65 and 98) from two CTX-M families (M1 and M9) were found. PFGE showed that the CTX-M-producing isolates were genetically diverse.
This study shows that food animals are a major reservoir of E. coli with multidrug resistance to many antibiotics that are ranked as critically important in human medicine.
- SourceAvailable from: Magdalena Rzewuska[Show abstract] [Hide abstract]
ABSTRACT: The antimicrobial susceptibility of Escherichia coli isolates associated with various types of infections in dogs and cats was determined. The studied isolates were most frequently susceptible to fluoroquinolones and the extended-spectrum cephalosporins (ESCs), antimicrobials commonly used in treatment of infections in companion animals. However, an increase in the percentage of strains resistant to í µí»½-lactam antibiotics including ESCs was noted between January 2007 and December 2013. The frequency of multidrug-resistant (MDR) E. coli isolation (66.8% of isolates) is alarming. Moreover, the statistically significant increase of the percentage of MDR isolates was observed during the study period. No difference in the prevalence of multidrug resistance was found between bacteria causing intestinal and extraintestinal infections and between canine and feline isolates. Nonhemolytic E. coli isolates were MDR more often than hemolytic ones. Our study showed the companion animals in Poland as an important reservoir of MDR bacteria. These results indicate that continuous monitoring of canine and feline E. coli antimicrobial susceptibility is required. Furthermore, introduction and application of recommendations for appropriate use of antimicrobials in small animal practice should be essential to minimize the emergence of multidrug resistance among E. coli in companion animals.The Scientific World Journal 01/2015; Volume 2015(Article ID 408205):8 pages. · 1.22 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: This study was focused on characterization of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates from chickens and CTX-M associated plasmid addiction systems (PASs) in E. coli from animals using molecular methods. In total, E. coli from nine (9.0%) of the 100 chicken samples examined produced CTX-M type ESBL namely CTX-M-14 (n=4), CTX-M-15 (n=4), and CTX-M-1 (n=1). All of them harbored an additional blaTEM-1 gene. Transfer of blaCTX-M gene was observed in eight out of the nine blaCTX-M-positive isolates by conjugation. Plasmid profiling of blaCTX-M-positive transconjugants revealed a high-molecular weight (95-165kb) plasmid. Pulsed-field gel electrophoresis showed that most CTX-M-producing chicken isolates were genetically diverse. Furthermore, investigation of 92 conjugation-positive E. coli strains carrying blaCTX-M genes from pigs (n=76), chickens (n=8), and dogs (n=8) identified 230 PASs in the parental strains and 118 in their transconjugants. Among them, hok-sok, pemKI, and pndAC were the most frequently represented PASs in both the parental strains and the transconjugants. Moreover, the hok-sok and pemKI systems were strongly associated to IncF plasmids and the pndAC system to IncI1-Iγ plasmids. Our results suggest that the rapid spread of CTX-M genes in E. coli isolates among the animals could be attributed to the presence of multiple PASs in the CTX-M plasmids. To our knowledge, this is the first report of characterization of CTX-M associated PASs in E. coli isolates from pigs, chickens, and dogs. In addition, CTX-M-1 was detected for the first time in Korea. Copyright © 2014 Elsevier B.V. All rights reserved.Veterinary Microbiology 10/2014; 174(3-4):456-462. · 2.73 Impact Factor
- [Show abstract] [Hide abstract]
ABSTRACT: The dissemination of drug-resistant bacteria from animal farms to aquatic environments can pose a potential threat to public health. In this study, antimicrobial resistance, resistance genes, and genetic similarity of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli of different origins (chicken feces and upstream and downstream river waters) were analyzed to track the spread of drug-resistant bacteria of animals. The results showed that a total of 29 ESBL-producing E. coli were obtained from 258 samples, and isolation rates of the ESBL-producing E. coli from chicken feces and upstream and downstream waters were 10.7% (16/150), 3.7% (1/27), and 14.8% (12/81), respectively. The ESBL-producing E. coli from upstream water was resistant to 7 antibiotics, but isolates from feces and downstream water had a higher resistance rate. In 29 ESBL-producing E. coli, the most common gene was CTX-M and the SHV gene was not detected. Five ESBL-producing isolates from downstream water showed >90% similarity with the fecal isolates, while the only one isolate from upstream water had <70% similarity with fecal isolates. The results suggest that animal farms' effluent, especially the untreated wastewater, could contribute to the spread of resistance genes. © 2014 S. Karger AG, Basel.Journal of Molecular Microbiology and Biotechnology 10/2014; 24(4):279-285. · 1.95 Impact Factor