Antimicrobial Resistance of Clostridioides (Clostridium) difficile in Cambodia

Background/Objectives: Antimicrobial resistance (AMR) remains a major topic of interest in infectious disease management. We studied AMR in Clostridioides difficile isolated in Cambodia. Methods: Agar dilution susceptibility testing was performed according to the CLSI guidelines to determine minimal inhibitory concentrations (MICs) of 10 antimicrobials for 192 isolates of C. difficile from four populations in Cambodia: hospitalised adults, hospitalised children, children from an outpatient department (OPD), and healthy adolescents in the community. Results: Using the CLSI MIC breakpoints for anaerobes and EUCAST breakpoints for C. difficile, all isolates were susceptible to vancomycin, metronidazole, fidaxomicin, and amoxicillin/clavulanic acid, and none were resistant to meropenem. The resistance proportions were for clindamycin, 88% (169/192); tetracycline, 50% (96/192); moxifloxacin, 20% (38/192); and rifaximin, 8% (15/192). Among the 169 clindamycin-resistant isolates, 56.8% (96/169) had an erythromycin MIC of >512 mg/L. Multidrug resistance (MDR) occurred in 20% (39/192) of the isolates, of which 82% (32/39) were non-toxigenic strains. The proportion of MDR varied between collections of isolates from different populations: 28.6% (22/77) in hospitalised adults, 29.8% (14/47) in hospitalised children, 5% (3/59) in OPD children, and none (00/07) in healthy adolescents in the community. Conclusions:C. difficile isolates from Cambodia remained susceptible to antimicrobials used to treat C. difficile infection: vancomycin, metronidazole, and fidaxomicin; however, high proportions of resistance to clindamycin and tetracycline were observed. The high number of MDR strains of C. difficile is a threat to AMR management in Cambodia and a factor contributing to the persistent spread of C. difficile in both hospital and community settings.