Objective: This study aimed to determine the prevalence of fecal carriage of antibiotic-resistant Escherichia coli of healthy household dogs with an emphasis on extended-spectrum b-lactamases (ESBL), AmpC-type blactamases and resistance to quinolones. Materials and Methods: Rectal swabs were collected from 74 dogs without any clinical evidence of gastrointestinal disease. Samples were cultured on MacConkey agar plates and MacConkey supplemented with 2 mg/mL cefotaxime or 5 mg/mL ciprofloxacin. Isolates were identified with Vitek 2 Compact and susceptibility testing performed by Kirby Bauer disk diffusion method. Minimal inhibitory concentration (MIC) was done on isolates resistant to cefotaxime, ciprofloxacin, and nalidixic acid. PCR amplification was performed to detect CTX-M and CMY-2. Isolates positive for CTX-M and/or CMY-2 were selected for whole-genome sequencing. Results: Multiresistance was detected in 56% of the isolates. A high percentage of resistance was detected for cefazolin (63%), ampicillin (54%), streptomycin (49%), nalidixic acid (42%) and tetracycline (38%). The MIC 50 and MIC 90 for isolates resistant to cefotaxime (24%) was determined as 16 and >250 mg/mL, respectively; for ciprofloxacin (18%), 125 and 250 mg/mL, respectively. ESBL (CTX-M type) and AmpC (CMY-2 type) were detected in 6 (7.1%) and 14 (19%) of the isolates, respectively. Whole-genome sequence analysis showed high genetic diversity in most of the isolates and a large variety of resistance mechanisms, including mobile genetic elements. Conclusion: The frequency of multidrug-resistant E. coli is worrying, mainly because of the presence of many isolates producing ESBL and AmpC b-lactamases. Based on the ''One Health'' concept, considering the relationships between animals, humans, and the environment, these data support the notion that companion animals are important reservoirs of multidrug-resistant bacteria.

This study's main objective was to analyze the antibiotic susceptibility profile of Escherichia coli isolates obtained from a fecal sample of a captive Baird's tapir (Tapirus bairdii) in Costa Rica. Materials and Methods: The fecal sample was collected inside the enclosure on March 3, 2017, right after the animal defecated. Samples were cultured on MacConkey agar plates nonsupplemented and supplemented with 2 mg/mL of cefotaxime. Bacterial identification and antibiotic susceptibility were performed with the Vitek 2 Compact System and the Kirby Bauer disk diffusion method, respectively. Polymerase chain reaction amplification was performed to detect bla CTX-M beta-lactamase genes. Resistant isolates were subjected to wholegenome sequencing (WGS). Results: After evaluating several antibiotic classes, a multidrug-resistant E. coli strain with extended-spectrum beta-lactamase phenotype was isolated. Resistance to cefotaxime, cefepime, ampicillin, ampicillin/sulbactam, and tetracycline was detected. WGS analysis showed the presence of bla CTX-M-1 , bla TEM-1B , and tet(B) genes. The presence of IncN plasmids and Col156 was also detected. Conclusion: Our findings are according with the notion that animals' high density enhances the spread of resistant determinants in a captive environment in a limited space, where the likelihood of direct or indirect contact with other animals and humans is more frequent.