Characterisation of extended spectrum β-lactamase and AmpC β-lactamase-producing Enterobacteriaceae isolated from companion animals in New Zealand
Creators: name: Karkaba, A
name: Grinberg, A
name: Benschop, J
name: Pleydell, E
Publisher: name: Taylor & Francis
Year: 2016
Subjects: subject: Space Science
subject: Microbiology
subject: FOS: Biological sciences
subject: Molecular Biology
subject: Environmental Sciences not elsewhere classified
subject: Ecology
subject: Immunology
subject: FOS: Clinical medicine
subject: Biological Sciences not elsewhere classified
subject: Infectious Diseases
subject: FOS: Health sciences

description: AIMS: To assess the occurrence of, and characterise, extended-spectrum-β-lactamase (ESBL) and AmpC-β-lactamase (AmpC)-producing <i>Enterobacteriaceae</i> isolated by veterinary diagnostic laboratories from infection sites in companion animals in New Zealand. METHODS: Selected <i>Enterobacteriaceae</i> isolates were submitted by seven New Zealand veterinary diagnostic laboratories. They were isolated from infection sites in companion animals between June 2012 and June 2013, and were resistant to amoxicillin-clavulanic acid, fluoroquinolones, or any combination of two or more antimicrobials. Based on disk diffusion test results, the isolates were phenotypically categorised according to production of ESBL and AmpC. Genes for ESBL and AmpC production were amplified by PCR and sequenced. <i>Escherichia coli</i> isolates were also typed by multilocus sequence typing. RESULTS: A total of 115 isolates matching the inclusion criteria were obtained from the participating laboratories, of which 74 (64%) originated from dogs and 29 (25%) from cats. Seven bacterial species were identified, of which <i>E. coli</i> was the most common (87/115, 76%). Of the 115 isolates, 10 (9%) expressed the ESBL phenotype, 43 (37%) the AmpC phenotype, and seven (6%) both ESBL and AmpC phenotypes. Of the 60 ESBL and AmpC-producing isolates, 36 (60%) were <i>E. coli</i>. Amongst these isolates, 27/60 (45%) were classified as multidrug resistant, compared with 15/55 (27%) non-ESBL or AmpC-producing isolates (p&lt;0.01). Ninety five isolates were resistant to amoxicillin-clavulanic acid and 58 (61%) of these were ESBL or AmpC-producing. The predominant ESBL genes were <i>bla</i><sub>CTX-M-14</sub> and <i>bla</i><sub>CTX-M-15</sub>, and the dominant plasmid-encoded AmpC gene was <i>bla</i><sub>CMY-2</sub>. Thirty-eight <i>E. coli</i> multilocus sequence types (ST) were identified, and the most prevalent were ST12 (12/89, 13%), ST131 (6/89, 7%) and ST648 (6/89, 7%). ESBL and AmpC-producing isolates accounted for 35/1,082 (3.2%) of the <i>Enterobacteriaceae</i> isolated by one laboratory network over the study period. CONCLUSIONS AND CLINICAL RELEVANCE: ESBL and AmpC-producing <i>Enterobacteriaceae</i> were associated with clinical infections in animals in New Zealand, and were often multidrug resistant. In this study, these organisms accounted for &lt;5% of all <i>Enterobacteriaceae</i> isolated from infection sites by one laboratory network, but their prevalence among isolates resistant to amoxicillin-clavulanic acid was 60%. Therefore routine secondary testing for ESBL and AmpC production by <i>Enterobacteriaceae</i> that are resistant to amoxicillin-clavulanic acid in primary testing could improve the accuracy of definitive antimicrobial therapy in companion animal practice in New Zealand.