Comparison of antimicrobial resistance in bacterial isolates from dogs in a veterinary diagnostic laboratory in Colombia, between two consecutive 4-year periods

Abstract

Background: Antimicrobial resistance (AMR) and the increase in multirresistant bacteria are among the most important threats to human and veterinary medicine according to the World Health Organization. Objective: To compare the antimicrobial susceptibility patterns in dog isolates in 2 consecutive 4-year periods. Methods: The veterinary diagnostic laboratory database at the Universidad de Antioquia was searched for routine dog submissions for which culture and antibiograms were performed. Results: A significant decrease between 2016-2019 and 2020-2023 was noted in the susceptibility of dog isolates to the following antimicrobials: Escherichia coli to amoxicillin-clavulanate (66.7-53.1%; p<0.01) and ampicillin (67.7-58%; p<0.05); Enterobacteriaceae to amikacin (100-94.3%; p<0.01), ampicillin (61.8-45.7%; p<0.01), and trimethoprim-sulfadiazine (83.9-75.6%; p<0.05); Staphylococcus pseudointermedius to gentamicin (63.9-52.5%; p<0.01), trimethoprim-sulfadiazine (57-50%; p<0.05) and doxycycline (60.9-43.4%; p<0.01). Significantly increased susceptibilities were also noted as follows: Escherichia coli to enrofloxacin (69.2-78.7%; p<0.05) and doxycycline (68.7-76.2%; p=0.0745), Enterobacteriaceae to enrofloxacin (64.4-79.3%; p<0.01) and doxycycline (38.7-47.7%; p=0.06). For all types of bacteria there was an increased resistance pattern against amoxicillin-clavulanate. All Staphylococcus species showed low resistance to amikacin (<10%); moderate resistance (10-20%) to amoxicillin-clavulanate, cephalexin, cefovecin, and enrofloxacin; high resistance (20-50%) to ampicillin, gentamicin, trimethoprim-sulfadiazine, and clindamycin; and very high resistance (50-70%) to doxycycline. For other families of bacteria, the number of antimicrobials for which resistance was high (20-50%), or very high (50-70%) was Enterobacteriaceae (7/9), Enterococcus spp. (4/7), E. coli (10/12), and Streptococcus spp. (4/6). For urinary tract infections caused by E. coli or Enterobacteriaceae (Klebsiella spp., Proteus spp.) amikacin and gentamicin were the only drugs that demonstrated low (<10%) in vitro resistance. Multidrug resistance slightly increased from 2016-2019 (18.7%; 247/1316) to 2020-August 2023 (19.7%; 150/761). This was attributed to a significant susceptibility reduction rather than susceptibility increases (28 versus 20). Conclusions: High rates of resistance indicate continued surveillance and use of antibiograms is needed to guide clinical decisions