Antimicrobial Resistance Patterns of ESBL-Producing in Dogs from Thailand: Evaluation of Algal Extracts as Novel Antimicrobial Agents.

Multidrug-resistant (MDR) bacteria, including extended-spectrum beta-lactamase (ESBL)-producing , in companion animals pose a growing public health concern due to the close interactions between pets and humans. This study aimed to investigate antimicrobial resistance patterns and the prevalence of ESBL-producing isolated from healthy dogs in Thailand, as well as the potential of algal extracts obtained through ethanol extraction and enzymatic hydrolysis as alternative antimicrobial agents against these drug-resistant organisms. Antimicrobial susceptibility testing was performed on 43 isolates from healthy dogs. ESBL production was confirmed using standard phenotypic methods, and resistance genes were detected by PCR. The algal extracts were tested for antibacterial activity against MDR isolates. Among the 43 isolates, 67.44% were classified as MDR, with high resistance rates observed for ampicillin (79.07%), tetracycline (65.12%), and ciprofloxacin (62.79%), highlighting significant antimicrobial resistance concerns. Of the MDR isolates, 31.03% (9/29) were confirmed as ESBL producers. Gene analysis revealed as the most prevalent gene (53.49%), followed by (9.30%), while was detected in a single isolate resistant only to ampicillin and was absent in all MDR strains. Ethanol extracts of and demonstrated inhibitory effects against MDR . MDR and ESBL-producing are prevalent in healthy dogs, posing a potential public health risk. Algal extracts from and show promise as alternative antimicrobials. Further research is necessary to optimize their efficacy and investigate their in vivo applications, including clinical and environmental settings.