Investigation of Antimicrobial Susceptibility in Clostridium Difficile Isolated From Older Adult Residents of a Nursing Home in Tehran

Background: CClostridium difficile is an anaerobic gram-positive bacterium currently recognized as the most common cause of nosocomial infectious diarrhea in the nursing home. The antibiotic susceptibility profiles are the basic step to successful treatment due to the antimicrobial resistance. This present study assessed the susceptibility profiles of C. difficile, previously isolated from Elderly residents of nursing homes in Tehran. Methods: Forty-two isolates of C. difficile were used, previously isolated from the older adult’s resident in Kahrizak nursing homes. Antibiotic susceptibility testing was conducted via disk-diffusion, agar dilution and Epsilometer test (E-test) methods.  Results: All C. difficile strains were susceptible to Metronidazole, Vancomycin, Rifampicin, Linezolid and Tigecycline. Also, the highest rate of resistance was seen in Clindamycin (100%), Levofloxacin (96.2%), Imipenem (81%), Azithromycin (61%) and Erythromycin (54.8%) disk-diffusion method. All C. difficile strains were susceptible to Metronidazole by E-test method.  Also, 100% and 59.5% of strains were susceptible to Vancomycin and Erythromycin by agar dilution methods, respectively. Conclusion: According to the results, C. difficile isolates were sensitive to Vancomycin and Metronidazole, as two main choice antibiotics used to treat C. difficile infections among the older adults. Also, the disk diffusion can be used as a screening test to determine the antibiotic resistance.