Antibiotic sensitivity pattern in blaNDM-1-positive and carbapenemase-producing Enterobacteriaceae

BACKGROUND: Some studies published in recent time revealed that many bacteria from Enterobacteriaceae group are multi-antibiotic-resistant because of the production enzymes carbapenemase particularly New Delhi metallo-beta-lactamase encoded by gene called blaNDM-1. Looking at public health importance of this issue there is a need for studies at other centers to confirm or refute published findings. OBJECTIVES: This study was designed with the aim of exploring antibiotic resistance in Enterobacteriaceae group of bacteria and also to explore gene and enzyme responsible for it. MATERIALS AND METHODS: Samples of Enterobacteriaceae were collected from wards and outpatient departments. Antibiotic sensitivity was checked by an automated system (VITEK 2 COMPACT). Carbapenemase production was assessed by Modified Hodge Test. Presence of blaNDM-1 was assessed by polymerase chain reaction. STATISTICS: Frequency and percentage were used to describe the data. Frequency of sensitivity was compared between carbapenemase producers and noncarbapenemase producers by Fisher's exact test. RESULTS: Forty-seven percent bacteria were found to be producing carbapenemase enzyme. These bacteria were significantly less sensitive to cefoperazone, cefepime, and amikacin. Among carbapenemase-producing organisms, 3% and 6% were resistant to tigecycline and colistin, respectively. Forty percent bacteria were found to be having blaNDM-1 gene. There was a significant difference between blaNDM-1-positive and blaNDM-1-negative for sensitivity toward cefoperazone + sulbactam, imipenem, meropenem, amikacin, tobramycine, ciprofloxacin, and levofloxacin. CONCLUSION: Presence of carbapenemase enzyme and blaNDM-1 gene is associated with high level of resistance in Enterobacteriaceae group of bacteria and only few antibiotics have good sensitivity for these organisms.