Identification and antibiogram of clinically relevant non-diphtheriae Corynebacterium species

Document Type : Original Article


Clinical Pathology Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt


Background:  With the increase in immunosuppressed patients and antimicrobial misuse, Non-diphtheriae Corynebacterium species (NDC spp.) have risen as opportunistic pathogens in hospitalized patients. The current work aimed at comparing Vitek 2C automated identification cards versus MALDI-TOF (Matrix-associated laser-induced desorption ionization-time of flight) as the gold standard method for the identification of different NDC spp. and determining the antimicrobial susceptibility of NDC spp. by the disc diffusion method for proper management of patients. Methods: Thirty NDC spp. isolates were subjected to identification by MALDI-TOF MS and Vitek 2C and antibiotic susceptibility testing by the disc diffusion method. Results: Our study showed that Corynebacterium (C.) striatum was the most commonly isolated species (83.3%), followed by C. amycolatum (10%). 36.7 % of the isolates were recovered from blood culture while 20 % were recovered from deep wounds. As regard isolate identification by Vitek-2C ANC ID CARD compared to MALDI-TOF as the gold standard method, the agreement was 86.7%. Regarding the antimicrobial susceptibility by disc diffusion method, all the isolates showed increased resistance against penicillin (100%), ciprofloxacin (70%), gentamicin (93.3%), tetracycline (76.6%), and clindamycin (70%). On the other hand, vancomycin and linezolid showed promising results where 100 % of the isolates were susceptible. Conclusion: We spotlight that NDC spp. is not viewed as a contaminant organism anymore, particularly in immunosuppressed patients. Timely identification, proper clinical correlation, and appropriate therapeutic intervention can lead to favorable outcomes.


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