Amala A. Andrews

Introduction: Shigellosis is an important cause of diarrhoeal mortality among children under five years. Even though shigellosis is mostly a self-limiting disease, antibiotics can attenuate the duration and severity of illness. However, drug resistance in Shigella is emerging as a significant public health problem. The choice of antimicrobial therapy for shigellosis should be made after accounting for local Antimicrobial Resistance (AMR) data. Aim: To analyse the pattern of Shigella infection including clinical profile, treatment, common species causing shigellosis, and their antimicrobial susceptibility pattern. Materials and Methods: This was a cross-sectional study conducted at Government Medical College, Kozhikode, Kerala, India from December 2017 to May 2019. A total of 60 Shigella isolates obtained from 1,646 stool samples of patients with suspected shigellosis were included in the study. Cultures were processed using standard microbiological methods. Identification was done using various biochemical tests and confirmed with agglutination using specific antiserum, followed by antimicrobial susceptibility testing using the Kirby-Bauer disc diffusion method and E-test. Multiplex Polymerase Chain Reaction (PCR) was done for every isolate to detect the presence of resistance genes. Culture-positive Shigella cases were evaluated for relevant demographic, clinical, therapeutic and microbiological variables. Results: A total of 60 isolates (3.64%) were obtained from 1,646 stool samples during the study period. Out of 60 isolates, 51 (85%) were Shigella sonnei, 9 (15%) were Shigella flexneri and 41 (68.33%) isolates were Multidrug Resistant (MDR was defined as resistance to at least one agent in three or more antimicrobial classes). Thirdgeneration cephalosporins were given for treatment in most cases. Ceftriaxone was resistant in 23 (38.3%) isolates and cotrimoxazole in 50 (83.3%) isolates. The commonest betalactamase gene identified was blaCTX-M-1 in 23 (38.3%) isolates. Among the genes responsible for resistance to cotrimoxazole, dhfr1A was the predominant one in 51 (85%) isolates and in fluoroquinolone resistance, qnrB was present in six isolates (10%). Conclusion: For tracking of AMR, especially regional monitoring among Shigella isolates is needed, since there is an emergence of multidrug resistance. Meropenem or azithromycin can be used as an alternative for the treatment of ceftriaxone-resistant shigellosis. Empirical therapy should be initiated in all shigellosis cases, and it should be based on the local antibiogram of Shigella isolates available.