Prevalence and pattern of multidrug resistant Gram-negative bacilli isolated from patients in the intensive care unit of a tertiary care hospital in Coastal Karnataka

Infections due to Gram negative bacilli (GNB) are the leading cause of mortality in ICU patients and are associated with higher morbidity rates, longer hospital stays and increased healthcare expenditures. Infections due to GNB in the ICU is about 2 to 5 times higher than in the general in-patient hospital population. This study aims to look at the prevalence of multi drug resistant gram-negative bacilli and proportion of ESBL producers in the MICU and to determine susceptibility patterns of GNB isolated, to various antibiotics. A total of 616 samples were collected from 396 patients admitted to the MICU during the 4-month study period. After the samples were inoculated and identified, the gram-negative isolates were subjected to Antibiotic susceptibility testing using Kirby Bauer Disc Diffusion technique with 17 different antibiotic disks. Strains showing decreased sensitivity to Ceftazidime/Cefotaxime were screened for ESBL production. Among the 616 samples tested, 149 (24.2%) samples showed growth of Gram-negative bacteria exclusively. Total number of GNB’s isolated were 173 due to some samples showing polymicrobial growth. The most common GNB found was (27.7%) which was followed by Klebsiella pneumonia at 26.0% and Acinetobacter baumannii at 18.5%. 64.2% of all GNB’s were Multi Drug Resistant which included 75% , 71.1% Klebsiella pneumoniae and 84.4% Acinetobacter baumannii. The study shows that the MDR GNB infections are on the rise in the ICU with GNBs being highly resistant to many previously effective first line antibiotics like Penicillins, newer Cephalosporins and Fluoroquinolones with susceptibility rates below 25% and even 0% for earlier generation Cephalosporins.