Antimicrobial resistance in equine faecal Escherichia coli isolates from North West England

Ahmed, Mohamed O.; Clegg, Peter; Williams, Nicola; Baptiste, Keith E.; Bennett, Malcolm J.

doi:10.1186/1476-0711-9-12

Cited by 84 publications

(94 citation statements)

References 33 publications

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“…Increased resistance in bacteria derived from hospitalized populations has been reported previously25 and also was clearly evident in the current study. Approximately 90% of isolates from ambulatory practices appeared susceptible to gentamicin (MIC ≤2 μg/mL) in contrast to approximately 40% of isolates from the hospital.…”

Section: Discussionsupporting

confidence: 89%

An evaluation of serum gentamicin concentrations and bacterial susceptibility to gentamicin in equine practice

Durham¹

2018

Veterinary Internal Medicne

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BackgroundTherapeutic drug monitoring and minimum inhibitory concentration (MIC) data allow more informed use of gentamicin.Hypothesis/ObjectivesTo measure peak and trough serum gentamicin concentrations in horses after a 6.6 mg/kg dose of gentamicin given IV and the MIC of gentamicin of bacteria for which gentamicin might be selected.MethodsRetrospective analysis of hospital records. Peak and trough plasma gentamicin concentrations were measured after 6.6 mg/kg gentamicin IV in 339 hospitalized horses. The MIC of gentamicin was measured for 503 isolates from ambulatory practice and 33 from hospital practice. The distribution of gentamicin concentrations and MIC results were compared to current recommendations for MIC breakpoints.ResultsThe median serum gentamicin concentration at 60 minutes after administration (C 60min) was 21.4 μg/mL with a distribution indicating that bacteria with MIC ≥2 μg/mL were unlikely to be exposed to sufficient gentamicin for effective killing. Approximately 90% of isolates from ambulatory practice and 36% of hospital isolates had MICs at or below breakpoints for susceptibility with most of the remainder unlikely to be responsive, even to higher IV doses.Conclusions and Clinical ImportanceGentamicin at a dosage of 6.6 mg/kg IV is likely to be effective against the majority of infections encountered in ambulatory practice, but less effective in an equine hospital. Because there was a dichotomy of most bacteria as being clearly susceptible or clearly resistant to gentamicin, it appears unlikely that higher doses would have been more efficacious, especially in the hospitalized population in our study.

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Section: Discussionsupporting

confidence: 89%

An evaluation of serum gentamicin concentrations and bacterial susceptibility to gentamicin in equine practice

Durham¹

2018

Veterinary Internal Medicne

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“…Actually, tet(A) and/or tet(B), encoding efflux mechanisms, has been reported to be the most common tetracycline resistance determinant in E. coli isolates from humans and animals in many countries (12,13,(20)(21)(22). Previous studies conducted in cattle disagree: some have reported that the tet(A) determinant is dominant in E. coli isolates recovered from cattle (23)(24)(25), whereas others found tet(B) to be dominant (26)(27)(28).…”

Section: Discussionmentioning

confidence: 66%

Prevalence of Antimicrobial Resistance and Transfer of Tetracycline Resistance Genes in Escherichia coli Isolates from Beef Cattle

Shin

Jung

et al. 2015

Appl Environ Microbiol

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bThe aim of this study was to investigate the prevalence and transferability of resistance in tetracycline-resistant Escherichia coli isolates recovered from beef cattle in South Korea. A total of 155 E. coli isolates were collected from feces in South Korea, and 146 were confirmed to be resistant to tetracycline. The tetracycline resistance gene tet(A) (46.5%) was the most prevalent, followed by tet(B) (45.1%) and tet(C) (5.8%). Strains carrying tet(A) plus tet(B) and tet(B) plus tet(C) were detected in two isolates each. In terms of phylogenetic grouping, 101 (65.2%) isolates were classified as phylogenetic group B1, followed in decreasing order by D (17.4%), A (14.2%), and B2 (3.2%). Ninety-one (62.3%) isolates were determined to be multidrug resistant by the disk diffusion method. MIC testing using the principal tetracyclines, namely, tetracycline, chlortetracycline, oxytetracycline, doxycycline, and minocycline, revealed that isolates carrying tet(B) had higher MIC values than isolates carrying tet(A). Conjugation assays showed that 121 (82.9%) isolates could transfer a tetracycline resistance gene to a recipient via the IncFIB replicon (65.1%). This study suggests that the high prevalence of tetracycline-resistant E. coli isolates in beef cattle is due to the transferability of tetracycline resistance genes between E. coli populations which have survived the selective pressure caused by the use of antimicrobial agents.A ntimicrobial resistance in humans and animals is considered a problem worldwide. Resistance to antimicrobial agents impedes the effective prevention and treatment of infectious disease, and thus, many governments have planned and implemented national programs for monitoring resistance in humans and animals (1-4). Surveillance data show that the inadequate selection and extensive use of antimicrobials result in the emergence and spread of resistant bacteria, particularly multidrug-resistant bacteria, and increase resistance to newer compounds, such as tetracycline-class antimicrobials (5).The tetracyclines are one of the most widely used classes of antimicrobial agents in human and veterinary medicine because they have several advantages, which include a broad spectrum of activity, low cost, oral administration, and few side effects (6). After chlortetracycline was introduced into clinical medicine in 1948, many derivatives, such as tetracycline, oxytetracycline, doxycycline, and minocycline, were developed, and today, these derivatives are widely used to treat disease and as growth promoters in the food animal industry. However, the widespread and indiscriminate use of tetracyclines has subjected bacterial populations to selection pressure and increased the prevalence of tetracycline resistance (6, 7).Tetracycline resistance is generally caused by the acquisition of a tetracycline resistance (tet) gene, as these genes are associated with primary resistance mechanisms, which involve active efflux pumps, ribosomal protection, and enzyme inactivation (8). To date, more than 40 different resist...

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“…A growing incidence of bla CMY-2 in recent years has been linked by some investigators to the extensive use of ceftiofur (25,67), an expandedspectrum veterinary cephalosporin, while others have suggested no significant impact of selection pressure on the frequency and transfer of the bla CMY-2 genes (13). Two recent studies investigating the mechanisms of ␤-lactam resistance in horses identified bla CTX-M-1 , bla CMY-2 , bla TEM-1 , and bla SHV-1 ␤-lactamase-encoding genes (1,73). However, to our knowledge, the bla CTX-M-2 gene has never been reported in bacteria of equine origin.…”

Section: /Equinementioning

confidence: 99%

Characterization of Multidrug-Resistant Escherichia coli Isolates from Animals Presenting at a University Veterinary Hospital

Karczmarczyk

Abbott

Walsh

et al. 2011

Appl Environ Microbiol

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In this study, we examined molecular mechanisms associated with multidrug resistance (MDR) in a collection of Escherichia coli isolates recovered from hospitalized animals in Ireland. PCR and DNA sequencing were used to identify genes associated with resistance. Class 1 integrons were prevalent (94.6%) and contained gene cassettes recognized previously and implicated mainly in resistance to aminoglycosides, ␤-lactams, and trimethoprim (aadA1, dfrA1-aadA1, dfrA17-aadA5, dfrA12-orfF-aadA2, bla OXA-30 -aadA1, aacC1-orf1-orf2-aadA1, dfr7). Class 2 integrons (13.5%) contained the dfrA1-sat1-aadA1 gene array. The most frequently occurring phenotypes included resistance to ampicillin (97.3%), chloramphenicol (75.4%), florfenicol (40.5%), gentamicin (54%), neomycin (43.2%), streptomycin (97.3%), sulfonamide (98.6%), and tetracycline (100%). The associated resistance determinants detected included bla TEM , cat, floR, aadB, aphA1, strA-strB, sul2, and tet(B), respectively. The bla CTX-M-2 gene, encoding an extended-spectrum ␤-lactamase (ES␤L), and bla CMY-2 , encoding an AmpC-like enzyme, were identified in 8 and 18 isolates, respectively. The mobility of the resistance genes was demonstrated using conjugation assays with a representative selection of isolates. High-molecular-weight plasmids were found to be responsible for resistance to multiple antimicrobial compounds. The study demonstrated that animal-associated commensal E. coli isolates possess a diverse repertoire of transferable genetic determinants. Emergence of ES␤Ls and AmpC-like enzymes is particularly significant. To our knowledge, the bla CTX-M-2 gene has not previously been reported in Ireland.

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Antimicrobial resistance in equine faecal Escherichia coli isolates from North West England

Cited by 84 publications

References 33 publications

An evaluation of serum gentamicin concentrations and bacterial susceptibility to gentamicin in equine practice

An evaluation of serum gentamicin concentrations and bacterial susceptibility to gentamicin in equine practice

Prevalence of Antimicrobial Resistance and Transfer of Tetracycline Resistance Genes in Escherichia coli Isolates from Beef Cattle

Characterization of Multidrug-Resistant Escherichia coli Isolates from Animals Presenting at a University Veterinary Hospital

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