Extensive dissemination of CTX-M-producing Escherichia coli with multidrug resistance to 'critically important' antibiotics among food animals in Hong Kong, 2008-10

Department of Microbiology and Carol Yu Centre for Infection, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong SAR, China.
Journal of Antimicrobial Chemotherapy (Impact Factor: 5.31). 03/2011; 66(4):765-8. DOI: 10.1093/jac/dkq539
Source: PubMed


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.

3 Reads
  • Source
    • "is crucial for effective therapy of these infections and substantially decreases the risk of development of multidrug resistance in these pathogenic or commensal bacteria. The antimicrobial resistance of canine and feline E. coli has been reported worldwide, including some European [1, 9, 12–14] and Asian [7] countries, the USA [6], Australia [15], and Brazil [16]. However, as far as the authors know, no data have been published yet regarding antimicrobial resistance profiles of E. coli isolates from dogs and cats in Poland. "
    [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. DOI:10.1155/2015/408205 · 1.73 Impact Factor
  • Source
    • "Another important host of these bacteria appears to be in wild rodents. Although these animals have previous been in the focus of research on ESBL in wildlife in different continents (Gilliver et al., 1999; Kozak et al., 2009; Guenther et al., 2010b; Literak et al., 2010b; Allen et al., 2011), they have only been detected in urban rats (Guenther et al., 2010a; Ho et al., 2011). On the other hand, VRE have been earlier described in wild rodents (Mallon et al., 2002). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Given the significant spatial and temporal heterogeneity in antimicrobial resistance distribution and the factors that affect its evolution, dissemination, and persistence, it is important to highlight that antimicrobial resistance must be viewed as an ecological problem. Monitoring the resistance prevalence of indicator bacteria such as Escherichia coli and enterococci in wild animals makes it possible to show that wildlife has the potential to serve as an environmental reservoir and melting pot of bacterial resistance. These researchers address the issue of antimicrobial-resistant microorganism proliferation in the environment and the related potential human health and environmental impact.
    Frontiers in Microbiology 02/2014; 5:23. DOI:10.3389/fmicb.2014.00023 · 3.99 Impact Factor
  • Source
    • "Fluoroquinolones, and cephalosporins are commonly used to treat gram-negative bacterial infections, especially some intestinal or extraintestinal infections caused by E. coli. Increasing resistant isolates, especially multidrug-resistant E. coli isolates, have been observed [10,11], due to the use of these antimicrobials, both in human and animal diseases over the past decades. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The association of PMQR and ESBLs in negative-bacteria isolates has been of great concern. The present study was performed to investigate the prevalence of co-transferability of oqxAB and bla CTX-M genes among the 696 Escherichia coli (E. coli) isolates from food-producing animals in South China, and to characterize these plasmids. The ESBL-encoding genes (bla CTX-M, bla TEM and bla SHV), and PMQR (qnrA, qnrB, qnrS, qnrC, qnrD, aac(6')-Ib-cr, qepA, and oqxAB) of these 696 isolates were determined by PCR and sequenced directionally. Conjugation, S1 nuclease pulsed-field gel electrophoresis (PFGE) and Southern blotting experiments were performed to investigate the co-transferability and location of oqxAB and bla CTX-M. The EcoRI digestion profiles of the plasmids with oqxAB-bla CTX-M were also analyzed. The clonal relatedness was investigated by PFGE. Of the 696 isolates, 429 harbored at least one PMQR gene, with oqxAB (328) being the most common type; 191 carried bla CTX-M, with bla CTX-M-14 the most common. We observed a significant higher prevalence of bla CTX-M among the oqxAB-positive isolates (38.7%) than that (17.4%) in the oqxAB-negative isolates. Co-transferability of oqxAB and bla CTX-M was found in 18 of the 127 isolates carrying oqxAB-bla CTX-M. These two genes were located on the same plasmid in all the 18 isolates, with floR being on these plasmids in 13 isolates. The co-dissemination of these genes was mainly mediated by F33:A-: B- and HI2 plasmids with highly similar EcoRI digestion profiles. Diverse PFGE patterns indicated the high prevalence of oqxAB was not caused by clonal dissemination. bla CTX-M was highly prevalent among the oqxAB-positive isolates. The co-dissemination of oqxAB-bla CTX-M genes in E. coli isolates from food-producing animals is mediated mainly by similar F33:A-: B- and HI2 plasmids. This is the first report of the co-existence of oqxAB, bla CTX-M, and floR on the same plasmids in E. coli.
    PLoS ONE 09/2013; 8(9):e73947. DOI:10.1371/journal.pone.0073947 · 3.23 Impact Factor
Show more