Microbiological Analysis of Sepsis in the Intensive Care Unit of a Tertiary Care Hospital in Chennai

Abstract

Hospital-acquired bloodstream infections are a prominent source of morbidity and mortality in intensive care
units (ICUs), with important clinical implications for patient length of stay and medical costs. A retrospective
study was undertaken from August 2023 to July 2024, with blood samples collected from sepsis patients in the
ICU and cultivated using the BacT/ALERT 3D Automated Microbial Detection system. The VITEK2 Automated
Bacteriological Identification system was used to identify organisms and determine their antimicrobial susceptibility
patterns. Out of a total of 2031 isolates, 429 were blood isolates from patients with sepsis in the ICU. 63.3% of
specimens were from males and 36.7% were from females. Age was divided into newborns (11.4%), 1–20 years
(4.6%), 21–30 years (10.7%), 31–40 years (6.99%), 41–50 years (20.3%), 51–60 years (23.5%), 61–70 years
(13.5%), 71–80 years (7.5%), and 81–90 years (1.4%). Departments were divided into respiratory ICU (36.1%),
medical ICU (31.3%), neonatal ICU (13.5%), surgical ICU (11.6%), and pediatric ICU (6.9%). Most common
organisms isolated were Klebsiella pneumoniae (29.8%), Acinetobacter baumannii (18.1%), Escherichia coli
(17.5%), and Staphylococcus aureus (11%). Antimicrobial susceptibility patterns were analyzed. Highest
susceptibility on average among Gram-positive cocci: Teicoplanin (91%), linezolid (100%), and vancomycin
(100%). Highest susceptibility on average among Gram-negative bacilli: Amikacin (52.1%), imipenem (51.73%),
and meropenem (51.73%). Much of the current understanding of the burden, causative pathogens, and clinical
outcomes of sepsis is based on clinico-epidemiological studies from developed countries. However, statistics
on the microbiological landscape and resistance patterns of sepsis in intensive care settings in Asian countries,
including India, remain limited and underexplored. Multiple studies within India and globally were analyzed for
this study to identify the significance of each microbiological parameter in relation to sepsis. This study shows
the distribution of frequently encountered bacteria and their antibiotic susceptibility in different ICUs in a tertiary
care hospital in Chennai. To limit the spread of multidrug-resistant diseases, different antibiotic regimens should
be explored for different wards and age groups.