title: Emergence of Carbapenem Resistant Non-Fermenting Gram-Negative Bacilli Isolated in an ICU of a Tertiary Care Hospital.
abstract: BACKGROUND
  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 speciesPseudomonas aeruginosa,Acinetobacter baumanniiandStenotrophomonas maltophiliaare 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.
  
  
  OBJECTIVE
  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.
  
  
  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 baumanniiwas the most common NFGNB isolated 63 (63.63%) followed byPseudomonas aeruginosa25 (25.25%),Elizabethkingia meningosepticaseven (7.07%) andStrenotrophomonas maltophiliafour (4.04%). We observed that 90.5%Acinetobacter baumanniiwere resistant to imipenem and 95.2% resistant to meropenem,Pseudomonas aeruginosacame out to be 52% resistant to imipenem and 56% resistant to meropenem whileStenotrophomonas maltophiliaandElizabethkingia meningosepticawere 100% resistant to carbapenems as they are intrinsically resistant to carbapenems.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Assistant Professor, Department of Critical Care Medicine, Himalayan Institute of Medical Sciences, SRHU , Dehradun, Uttarakhand, India .
authors.forename: Sonika
authors.initials: S
authors.lastname: Agarwal
authors.affiliation: Associate Professor, Department of Microbiology, Himalayan Institute of Medical Sciences, SRHU , Dehradun, Uttarakhand, India .
authors.forename: Barnali
authors.initials: B
authors.lastname: Kakati
authors.affiliation: Assistant Professor, Department of Critical Care Medicine, Himalayan Institute of Medical Sciences, SRHU , Dehradun, Uttarakhand, India .
authors.forename: Sushant
authors.initials: S
authors.lastname: Khanduri
authors.affiliation: Senior Resident, Department of Microbiology, Himalayan Institute of Medical Sciences, SRHU , Dehradun, Uttarakhand, India .
authors.forename: Shalini
authors.initials: S
authors.lastname: Gupta
keywords: Acinetobacter; Imipenem; Meropenem; VITEK 2