Laboratory Analysis of the Resistance Spectrum and Antibacterial Susceptibility of Vibrio cholerae Strains Isolated in Kazakhstan from 1970 to 2024

C holera is an acute diarrheal disease caused by the bacterium Vibrio cholerae , transmitted via the fecal–oral route, primarily through contaminated water or food. Despite progress in vaccination and antibiotic use, cholera continues to pose a significant public health threat, especially in regions with inadequate sanitation and unsafe drinking water. A major challenge in the management of cholera is the emergence of antibiotic-resistant V. cholerae strains, which compromise the effectiveness of standard therapeutic regimens. These resistant strains necessitate the development of novel treatment and prevention strategies. In 2018, studies on phenotypic resistance markers in Vibrio cholerae isolates collected in Kazakhstan revealed that 38.4% of the examined strains exhibited resistance, with monoresistant strains predominating (23.1%). Additionally, 9.6% of the isolates carried two or more resistance markers. Among the Vibrio cholerae O1 serogroup isolates, 38.5% were resistant, while in the non-O1 serogroup, resistance was observed in 40.0% of cases. Objectives: In this study, a comprehensive analysis was conducted on the antibiotic resistance of Vibrio cholerae strains isolated in Kazakhstan from 1970 to 2024, focusing on their susceptibility to various classes of antimicrobial agents. The molecular and biochemical mechanisms underlying the development of resistance were also investigated, and potential impacts on the epidemiological situation and biosafety were assessed. Methods : In this study, a total of 26 Vibrio cholerae strains isolated in Kazakhstan between 1970 and 2024 from clinical cases and environmental sources were used to screen for antimicrobial susceptibility and resistance profiles. Susceptibility testing was performed using the Kirby–Bauer disk diffusion method and E-test. To detect resistance genes, phenotypic assays and real-time Polymerase Chain Reaction were applied. One reference strain, 59 antibacterial agents across major drug classes, and a BacResista GLA Real-Time PCR Detection Kit were employed. Results : Phenotypic susceptibility testing of V. cholerae (n = 26) conducted in vitro demonstrated high sensitivity to cefotaxime, tetracycline, doxycycline, ciprofloxacin, and kanamycin. A similarly high level of susceptibility was observed for gentamicin, chloramphenicol, ampicillin, and rifampicin (96.2% of isolates). Real-time PCR results revealed no presence of resistance genes to glycopeptide or beta-lactam antibiotics in the tested V. cholerae strains. However, van A/B genes (Ct = 9.166, FAM channel) and the tem gene (Ct = 34.60, CY5 channel) were detected in the control strains Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 9027 (Ct = 8.954 and 24.85, respectively). Conclusions : The absence of resistance to major classes of antimicrobial agents among all 26 V. cholerae isolates indicates the continued high clinical efficacy of these antibiotics in the treatment of cholera. These findings are of critical importance in the context of potential epidemic outbreaks, as they provide clinicians with a reliable basis for selecting empirical therapy.