Molecular characterization of virulence factors and antimicrobial susceptibility of thermophilic Campylobacter species associated with human clinical infections in Rwanda

Background Campylobacter species are among the leading causes of bacterial gastroenteritis globally. In Rwanda, limited data exist on their molecular characteristics and antimicrobial resistance (AMR) profiles. This study investigated the virulence gene profiles and antimicrobial susceptibility of thermophilic Campylobacter species isolated from human clinical infections in northern Rwanda. Methods A cross-sectional study was conducted between March and July 2025 among 200 symptomatic patients at Ruhengeri Hospital. Stool samples were cultured under microaerophilic conditions, and presumptive Campylobacter isolates were confirmed by PCR targeting the 16S rRNA and mapA genes. Virulence genes ( flaA , cadF , cdtA , cdtB , cdtC ) were characterized by PCR. Antimicrobial susceptibility testing (AST) was performed using the Kirby-Bauer disc diffusion method against ciprofloxacin, erythromycin, tetracycline, gentamicin, and chloramphenicol following EUCAST guidelines. Results Sixteen (8%) thermophilic Campylobacter isolates were confirmed, predominantly C. jejuni (93.8%). All isolates harbored flaA and cadF genes, while cdtA and cdtB were present in 93.8% and cdtC in 81.3%. All isolates (100%) were resistant to erythromycin, 81.3% to ciprofloxacin (resistant/intermediate), and 75.0% to tetracycline, while complete sensitivity to chloramphenicol and 87.5% sensitivity to gentamicin were observed. Over half (56.3%) of isolates exhibited multidrug resistance (MDR), primarily to erythromycin, ciprofloxacin, and tetracycline. Conclusion The study reveals high virulence gene prevalence and alarming resistance rates among Campylobacter isolates from clinical infections in Rwanda. The universal resistance to erythromycin and high rates of ciprofloxacin and tetracycline resistance highlight the urgent need for enhanced AMR surveillance, rational antibiotic use, and One Health-based control strategies. The retained susceptibility to chloramphenicol and gentamicin offers limited but valuable therapeutic alternatives.