Nosocomial infections in the medical ICU: a retrospective study highlighting their prevalence, microbiological profile and impact on ICU stay and mortality

Abstract

Objectives: 1. To study the prevalence of nosocomial infections in the Medical ICU. 2. To determine common microorganisms causing nosocomial infections in the ICU and their antibiotic- sensitivity profile. 3. To study the impact of nosocomial infections on ICU stay and mortality.

Methods: A retrospective 1 year analysis of nosocomial infections in the Medical ICU at Smt. Kashibai Navale Medical College and Hospital, Pune, between January and December 2011 was carried out. Prevalence of nosocomial infections was determined; sites of nosocomial infections and common causative microorganisms were identified; their antibiotic-sensitivity profiles were studied. The group of patients with nosocomial infections was matched with a control group drawn from the pool of patients without nosocomial infections; this matching was done with respect to age, gender and clinical diagnosis. Period of ICU stay and patient mortality rates in the two groups were analysed.

Results: A total of 366 ICU patient records were analysed. Of these, 32 patients were found-to have developed 35 nosocomial infections (9.6% prevalence), of which respiratory infections were the commonest (65.8%), followed by urinary infections (17.1%) and dual infections (urinary plus respiratory) (17.1%).The most frequently isolated microorganism causing respiratory infections was Acinetobacter (40.4%), 21% isolates of which were multidrug resistant; whereas the most frequently isolated microorganism causing urinary tract infections was Pseudomonas (38.4%). Average ICU stay in patients with and without nosocomial infections was 16.5 and 6.4 days respectively; whereas mortality in the two groups was 28.1% and 31.2% respectively. Overall ICU mortality was 19.9%.

Conclusion: The nosocomial infection rate in our ICU was in keeping with the rate in many industrialised countries. The most common site of nosocomial infection was the respiratory tract, followed by the urinary tract. Acinetobacter was the commonest respiratory isolate, whereas Pseudomonas was the commonest urinary isolate. One fourth of Acinetobacter isolates were multidrug resistant. Nosocomial infections resulted in a statistically significant increase in ICU stay; whereas there was no impact on ICU mortality.