Bacterial colonization in tracheal tubes of intensive care unit patients: Study from a tertiary care centre

Introduction – Invasive diagnostic and therapeutic methods have saved many lives. On the other hand it can cause some life threatening consequences due to infections. Bacterial infection in the lower respiratory tracts remains a main complication of tracheal intubation. The incidence of nosocomial pneumonia varies from 9% to 68%. Knowledge of susceptibility pattern is helpful in selecting the empirical therapy.
Objectives - To determine prevalence and antibiotic susceptibility profile of bacteria colonizing tracheal tubes in the ICU.
Methodology - The study was carried out for a period of 3 years during 2012- 2014. Data of total 5319 samples for culture and sensitivity were recorded in WHONET 5.6 and analyzed. Colony count of 105cfu/mL is considered significant. Culture pairs were assessed for change in (1) species of bacteria isolated and (2) change in empiric antibiotic coverage. The results were analyzed using appropriate statistical methods.
Results - Culture of 5319 samples yielded 3268 isolates from 1232 patients. Positive culture rate was 55%. The most frequently isolated organism was Acinetobacter baumannii followed by Pseudomonas aeruginosa, Klebsiella pneumoniae, E.coli, Proteus mirabilis. High level of resistance to imipenem (ranged 30%-60%) and meropenem (ranged 50%-70%) is an alarming sign. Colistin resistant was not detected. Staphylococcus aureus was isolated with >60% MRSA rates. Change in flora was present in around 72 % patients. Additional antibiotic coverage was needed in around half of the patients.
Conclusions - This study presents the most common microorganisms colonized and their antibiotic resistance pattern. The variability of flora and the potential need to adjust antibiotic coverage based on culture data suggest that surveillance tracheal aspirates are important during exacerbations.