Trends and antibiotic susceptibility patterns of diarrhoeal pathogens – experience over 14 years in southern India

<b>Introduction</b>. Enteric pathogens contribute significantly to morbidity in a developing country such as India. Early and prompt diagnosis of diarrhoeal diseases can reduce the mortality rate, particularly in children. The pattern of sensitivity to antimicrobials for the common pathogens can vary from time to time. The present study was conducted to study the pathogen distribution and antimicrobial susceptibility pattern during the study period (January 2010 to December 2023). <b>Hypothesis/gap statement</b>. Studying the changing trend in the antimicrobial sensitivity pattern of diarrhoeal pathogens over a decade can help to plan future treatment options. <b>Aim</b>. This study was undertaken to provide insights into the changing pattern of pathogen distribution and antimicrobial susceptibility for enteric pathogens over 14 years. <b>Methods</b>. A retrospective observational cohort analysis was conducted on all the stool pathogens isolated from the samples received in the microbiology department of a tertiary care hospital from 2010 to 2023. The demographic details, stool microscopy, culture reports, and antimicrobial susceptibility patterns were noted. <b>Results</b>. A total of 18 336 stool specimens were received in the microbiology laboratory between January 2010 and December 2023, of which 1354 specimens had diarrhoeal pathogens grown in culture. Out of these 1354 specimens, 591 (44%) had <i>Salmonella</i>, 471 (35%) <i>Shigella</i>, 181 (13%) <i>Vibrio cholerae,</i> and 80 (6%) <i>Aeromonas</i> species. Among these pathogens, susceptibility to ceftriaxone was seen in 93% (552 isolates) of <i>Salmonella</i> species, 89% (420 isolates) of <i>Shigella</i> species, and 95% (171 isolates) of <i>Vibrio cholerae</i>; 91% (73 isolates) of <i>Aeromonas</i> species were susceptible to chloramphenicol. Some major parasites were also observed on microscopy. <b>Conclusion</b>. Timely diagnosis of diarrhoeal pathogens can be life-saving for patients at the extremes of age, i.e. in children and the elderly. Pathogens can exhibit a changing susceptibility pattern to antibiotics, which should be regularly observed to plan future therapy.