Phenotypic and Genotypic Characteristics of Clostridium difficile Isolates in Patients with Type 2 Diabetes in Iran

Abstract

Purpose: This study aimed to investigate the phenotypic and genotypic characterization of Clostridium difficile isolates in type 2 diabetes patients with hospital-acquired diarrhea in four teaching hospitals in Isfahan, Iran. Patients and Methods: A total of 104 hospitalized patients with type 2 diabetes and nosocomial diarrhea were included in the current study over a 2-year period (2015-2017). C. difficile isolates were characterized by conventional microbiological methods including the presence of toxin genes, antibiotic resistance testing and molecular methods including multilocus sequence typing (MLST) and random amplification of polymorphic DNA (RAPD). Results: All 21 C. difficile isolates (20.2) were detected from 104 studied patients. All isolates were susceptible to metronidazole and vancomycin. The antimicrobial resistance rates were distinctly higher for clindamycin and for moxifloxacin. Based on PCR amplification of tcdA and tcdB, 13 isolates (12.5) carried both of these genes and were considered toxigenic. Thirteen toxigenic C. difficile strains were classified into two sequence types (STs), that is, ST54 and ST2 types. The RAPD-PCR amplification patterns of the detected toxigenic C. difficile revealed three distinct but related RAPD clusters. RAPD cluster 1 had the highest similarity with RAPD types 2 and 3. Conclusion: A relatively high rate of CDI was observed in patients with type 2 diabetes and was associated with poorer health outcomes. These patients were exposed to multiple antibiotics and other therapeutic agents. We recommend close screening for the coexistence of CDI and type 2 diabetes in patients with diarrhea using a combination of conventional and molecular methods.