Divergent evolution of Corynebacterium diphtheriae in India: An update from National Diphtheria Surveillance network

• Published in: PloS one 2021-12, Vol.16 (12), p.e0261435
• Main Authors: Devanga Ragupathi, Naveen Kumar, Muthuirulandi Sethuvel, Dhiviya Prabaa, Murugan, Dhivya, Ranjan, Ranjini, Gautam, Vikas, Gupta, Prashanth, Johnson, Jaichand, Sharma, Naresh Chand, Mutreja, Ankur, Haldar, Pradeep, Kumar, Arun, Bhatnagar, Pankaj, Sangal, Lucky, Veeraraghavan, Balaji
• Format: Article
• Language: English
• Subjects: Analysis; Anti-Bacterial Agents - pharmacology; Antiinfectives and antibacterials; Bacterial proteins; Biochemical tests; Biology and Life Sciences; Cefotaxime; Cefotaxime - pharmacology; Cloning; Corynebacterium diphtheriae - classification; Corynebacterium diphtheriae - drug effects; Corynebacterium diphtheriae - genetics; Corynebacterium diphtheriae - isolation & purification; Diagnosis; Diphtheria; Diphtheria - epidemiology; Divergence; Epidemics; Epidemiological Monitoring; Epidemiology; Erythromycin; Erythromycin - pharmacology; Humans; India - epidemiology; Laboratories; Medical schools; Medicine and Health Sciences; Microbial Sensitivity Tests; Molecular Epidemiology; Morbidity; Mortality; Multilocus Sequence Typing; Pathogens; Penicillin; Penicillins - pharmacology; People and Places; Personal health; Prevention; Research and Analysis Methods; Surveillance; Vaccines
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0261435

Diphtheria is caused by a toxigenic bacterium Corynebacterium diphtheria which is being an emerging pathogen in India. Since diphtheria morbidity and mortality continues to be high in the country, the present study aimed to study the molecular epidemiology of C. diphtheriae strains from India. A total of 441 diphtheria suspected specimens collected as part of the surveillance programme between 2015 and 2020 were studied. All the isolates were confirmed as C. diphtheriae with standard biochemical tests, ELEK's test, and real-time PCR. Antimicrobial susceptibility testing for the subset of isolates showed intermediate susceptibility to penicillin and complete susceptible to erythromycin and cefotaxime. Isolates were characterized using multi locus sequence typing method. MLST analysis for the 216 C. diphtheriae isolates revealed major diversity among the sequence types. A total of 34 STs were assigned with majority of the isolates belonged to ST466 (30%). The second most common ST identified was ST405 that was present in 14% of the isolates. The international clone ST50 was also seen. The identified STs were grouped into 8 different clonal complexes (CC). The majority belongs to CC5 followed by CC466, CC574 and CC209, however a single non-toxigenic strain belongs to CC42. This epidemiological analysis revealed the emergence of novel STs and the clones with better dissemination properties. This study has also provided information on the circulating strains of C. diphtheriae among the different regions of India. The molecular data generated through surveillance system can be utilized for further actions in concern.