# P-2097. Trends in Antibiotic Resistance Among Clinical Isolates in Rural Tamil Nadu: A Prospective Observational Study

## TL;DR

This study tracks antibiotic resistance in rural Tamil Nadu, finding high resistance to common antibiotics among bacteria like E. coli and Klebsiella.

## Contribution

The study provides up-to-date resistance profiles in rural India, highlighting emerging threats like carbapenem resistance and guiding local antibiotic use.

## Key findings

- E. coli showed high resistance to ciprofloxacin, co-trimoxazole, and third-generation cephalosporins.
- Klebsiella pneumoniae exhibited 76% resistance to cefotaxime and 18% carbapenem resistance.
- MRSA prevalence was 39%, but all isolates remained susceptible to vancomycin and linezolid.

## Abstract

Antimicrobial resistance (AMR) is a major public health concern, particularly in low-resource rural settings with limited antimicrobial stewardship. Rural Tamil Nadu represents a critical region to monitor resistance patterns due to major OTC antibiotic misuse This study assessed antibiotic resistance profiles of bacterial isolates from clinical specimens in rural Tamil Nadu, India.

A prospective observational study was conducted from October 2024 to February 2025 across three rural primary health centers in Tamil Nadu, India. Clinical specimens (urine, sputum, blood) were processed using standard microbiological methods. Bacterial identification and antibiotic susceptibility testing (Kirby-Bauer disk diffusion) were performed. Resistance trends were stratified by specimen type and organism.

A total of 952 clinical isolates were recovered from 1,229 specimens. The most common organisms: Escherichia coli (32.7%), Klebsiella pneumoniae (18.4%), Staphylococcus aureus (15.3%), Pseudomonas aeruginosa (11.7%), and Enterococcus spp. (7.2%).

• E. coli showed high resistance to ciprofloxacin (78%), co-trimoxazole (64%), and third-generation cephalosporins (ceftriaxone 71%; cefotaxime 68%) with lower resistance to nitrofurantoin (22%) and meropenem (9%).

• K. pneumoniae showed resistance to cefotaxime (76%), gentamicin (52%), and amoxicillin-clavulanate (65%); 18% were carbapenem-resistant.

• MRSA prevalence was 39% with 100% susceptibility to vancomycin and linezolid.

• P. aeruginosa demonstrated multi-drug resistance (resistance to ≥3 classes) in 27% of isolates, retaining susceptibility to amikacin (81%) and piperacillin-tazobactam (74%).

• Enterococcus spp. showed 100% linezolid susceptibility with ampicillin (41%) and vancomycin (5%) resistance.

Alarming resistance rates were observed against first-line antibiotics, including emerging carbapenem resistance in Klebsiella spp. and E. coli (indicative of ESBL/carbapenemase production). MRSA and vancomycin-resistant Enterococcus highlight urgent needs for local stewardship programs. These findings can guide empirical therapy and inform regional antibiotic guidelines to preserve antimicrobial efficacy in resource-limited rural settings.

All Authors: No reported disclosures