Bacteriological profile and antibiotic susceptibility pattern of secondary peritonitis in correlation to the anatomical site of gastrointestinal perforation: A Retrospective Study

Abstract

Background

The mortality and morbidity due to secondary peritonitis is high. Timely surgical intervention of secondary

peritonitis due to Gastrointestinal (GI) perforation and appropriate empirical antibiotic therapy are prerequisites

for a good outcome in these cases. The study aims to investigate the bacterial profile and the antibiotic

susceptibility pattern of bacterial isolates in cases of secondary peritonitis following GI perforation and the

correlation of bacterial spectrum with the different anatomical sites of GI perforation.

Methods

The retrospective study includes 44 patients operated on for secondary peritonitis following GI perforation

between Jan 2019 to March 2020. The peritoneal fluid samples from these patients were subjected to bacterial

culture and sensitivity. The bacterial isolates were identified by standard microbiological techniques and antibiotic

susceptibility pattern was determined by the Kirby Bauer disk diffusion method and E test. The clinical data about

the anatomical site of gastrointestinal perforation was collected from the medical records of these patients and

were analyzed.

Results

Out of 44 peritoneal fluid samples obtained from secondary peritonitis cases due to GI perforation, 58 bacterial

strains were isolated. The majority of the bacterial isolates were Gram-negative bacilli; Escherichia coli 31/58

(53.44%), Klebsiella pneumoniae 16/58 (27.58%) and Enterobacter spp. 5/58 (8.62%). The Gram-positive bacteria

accounted for 10.33% of the infections; Enterococcus spp. 4/58 (6.89%) and Staphylococcus aureus 2/58 (3.44%).

The most common anatomical site of GI perforation was Appendix in 63% of the cases, followed by the stomach

in 16% and the small intestine in 14% of the study cases. Meropenem was found to have the highest susceptibility

rate among all Gram-negative bacteria. Vancomycin and Linezolid were effective in all localizations with a

sensitivity rate of 100%.

Conclusion

By evaluating the microbial flora and its antibiotic susceptibility pattern in relation to the location of perforation

and microbial flora, we recommend Meropenem and Linezolid as the choice for empirical antibiotic therapy in

cases of secondary peritonitis following GI perforation.