Emergence of Carbapenem Resistant Non-Fermenting Gram-Negative Bacilli Isolated in an ICu of a Tertiary Care Hospital

INTRODUCTION: The emergence and spread of Multi-Drug Resistant (MDR) Non-Fermenting Gram-Negative Bacilli (NFGNB) in Intensive Care Units (ICU) and their genetic potential to transmit diverse antibiotic resistance regardless of their ability to ferment glucose poses a major threat in hospitals. The complex interplay of clonal spread, persistence, transmission of resistance elements and cell-cell interaction leads to the difficulty in controlling infections caused by these multi drug-resistant strains. Among non-fermenting Gram-negative rods, the most clinically significant species Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia are increasingly acquiring resistant to carbapenems. Carbapenems once considered as a backbone of treatment of life threatening infections appears to be broken as the resistance to carbapenems is on rise. AIM: To document the prevalence of carbapenem resistance in non-fermenting Gram-negative bacilli isolated from patients with respiratory tract infections in the ICU of Himalayan Institute of Medical Sciences, Dehradun. MATERIALS AND METHODS: This is a cross-sectional study conducted in ICU patients between October 2015 to March 2016. A total of 366 lower respiratory tract samples were collected from 356 patients with clinical evidence of lower respiratory tract infections in form of Endotracheal (ET) aspirate, Tracheal Tube (TT) aspirate and Bronchoalveolar Lavage (BAL) specimen. Organism identification and the susceptibility testing was done by using an automated system VITEK 2. RESULTS: Out of 366 samples received 99 NFGNB were isolated and most common sample was ET aspirate sample 256 (64.5%). Acinetobacter baumannii was the most common NFGNB isolated 63 (63.63%) followed by Pseudomonas aeruginosa 25 (25.25%), Elizabethkingia meningoseptica seven (7.07%) and Strenotrophomonas maltophilia four (4.04%). We observed that 90.5% Acinetobacter baumannii were resistant to imipenem and 95.2% resistant to meropenem, Pseudomonas aeruginosa came out to be 52% resistant to imipenem and 56% resistant to meropenem while Stenotrophomonas maltophilia and Elizabethkingia meningoseptica were 100% resistant to carbapenems as they are intrinsically resistant to carbapenems. CONCLUSION: The resistance rate of carbapenems for NFGNB infections is very high in our study and variable in different regions. Overall carbapenem resistance is on rise. So, the infection control team and microbiologist needs to work together to determine the risk carried by multi drug resistant non-fermenting gram-negative infections and the resistance surveillance programs are mandatory to control these bacteria in ICU settings.