Epidemiology of hospital acquired infections among patients admitted in the intensive care unit in a tertiary care hospital

Background: Hospital - acquired infection (HAI) is a leading cause of morbidity and mortality among hospitalized patients that increases. More than 20% of all nosocomial infections are acquired in Intensive care unit (ICU). The risk of HAI in ICU is 5 to 10 times greater than those acquired in general medical and surgical wards. The emergence of resistance to antimicrobial agents has been increased in recent years. To ensure appropriate therapy current knowledge of the organisms causing HAIs and there susceptibility pattern is mandatory. Aims and objectives: The purpose of this study is to evaluate the microbiological profile and the susceptibility pattern of the micro-organisms isolated from various samples of adult patients admitted in ICU and suspected of having hospital acquired infections after admission in a tertiary care hospital in Kolkata, West Bengal, India Result: Total 120 samples from patients admitted in ICU were processed in the laboratory out of which, 70 (58.33%) showed culture to be positive and 50(41.67%) samples showed no growth of any organism. The rate of infection in ICU of our set-up was 56.25 %. Culture positivity was 71.92% among those having length of stay in ICU for >7 days. This association was statistically significant. 41.17% of blood samples, 88.23% of respiratory samples, 42.85% of urine samples and 100% of pus samples showed culture positivity. Culture positivity was associated with presence of in-situ devices and this association was found to be statistically significant. Pneumonia (43%) was found to be most common infections in the ICU of our set-up followed by blood stream infections (30%) and urinary tract infections (17%). Acinetobacter spp was found to be the most common agent causing bacteremia (42.85%) and pneumonia (40%) in our set-up. Most of the gram negative isolates specially Acinetobacter spp showed resistance to commonly prescribed antibiotics. Vancomycin and Linezolid resistance is also becoming common in the ICU setup along with prevalence of MRSA strains. Conclusion: In ICU associated infections it is important to know the possible microorganisms and their sensitivity patterns for the success of the selection of the empiric antibiotic treatment. Regular surveillance of these infections to estimate the burden of infection is an essential step in the infection control and quality care assurance to patients.