Detection of ESBLs producing Escherichia coli isolated from dog faeces from La Plata city.

GORTARI, LIHUEL; BUCHAMER, ANDREA; MARCHETTI, MARÍA LAURA; BULDAIN, DANIEL; ALIVERTI, FLORENCIA; CHIRINO TREJO, MANUEL; MESTORINO, NORA

Roma

Conferencia; Ninth International Conference on Antimicrobial Agents In Veterinary Medicine (AAVM); 2018

The great increase in strains carrying extended spectrum beta-lactamases (ESBL) is a problem worldwide. Pets would have a possible role as reservoirs for ESBLs. Enterobacteriaceae are the mainly producers of ESBL, particularly Klebsiella pneumoniae and Escherichia coli. ESBLs are plasmid-mediated enzymes that hydrolyze penicillins, third generation cephalosporins and aztreonam, but are susceptible to beta-lactamase inhibitors (clavulanic acid). Escherichia coli among intestinal microbiome, has a role of resistance indicator bacteria. The surveillance of its resistance mechanisms is an important tool in the control of antimicrobials non-prudent use. Our objective was to detect ESBLs produced by E. coli strains isolated from pet and stray dogs of La Plata city, Buenos Aires, Argentina. Samples were collected using rectal swabs from 50 home dogs (HD) and 50 stray dogs (SD). Strains were stained by Gram and typified by biochemical tests. Susceptibility profiles for 20 antimicrobials was performed by standard Kirby-Bauer disk diffusion method, and the first ESBL disc screening was evaluated using cefpodoxime, ceftazidime, aztreonam, cefotaxime and ceftriaxone. For the ESLBs?s confirmation, the Double-Disc Synergy Test was done: discs containing cetazidime, cefpodoxime were applied next to a disc with amoxicillin plus clavulanic acid (20 mm center to center). Positive result is indicated when the inhibition zones around any of the cephalosporin discs were augmented in the direction of the disc containing clavulanic acid. E. coli ATCC 25922 was used for quality control. There were multiresistant strains in both groups and their resistance profile includes one, two, three and more than four antimicrobials. Multiresistance occurrence was considerably higher in SD strains (42% of multiresistance to more than 4 antimicrobials). There were 8 % of strains suspected of being ESLBs producing among samples of HD and 36 % of SD. One of the strains ESBL suspected of HD (2%) and 11 (22%) of SD, were confirmed. Conclusion: ESBLs producing strains identification, is an essential tool to achieve efficacy in the antimicrobial therapy. It is important to know the development of antimicrobial resistance by monitoring not only animals at home, but also those homeless ones.