Published: 2016-12-27

Ease with VITEK 2 systems, biomerieux in identification of non-lactose fermenting bacteria including their antibiotic drug susceptibility: our experience

Susmitha Simgamsetty, Padmaja Yarlagadda, Bindu Madhav Yenigalla, Ramesh Babu Myneni


Background: Nonfermenters are being isolated from various clinical specimens. Although frequently considered as contaminants, the pathogenic potential has been proved beyond doubt by their frequent isolation from clinical material and their association with disease. In the recent years due to the liberal and empirical use of antibiotics, Non Fermenting Gram Negative Bacilli (NFGNB) have emerged as important health care associated pathogens. Several automated systems are available for the identification and susceptibility of the clinically important bacteria. In this study we have evaluated the ease of the VITEK-2 Compact in identifying the NFGNB along with its antibiotic sensitivity.

Methods: A total of 186 strains which grew in culture from various clinical specimens isolated at the Clinical Microbiology Laboratory, NRI General Hospital, Chinakakani, Guntur District, A.P. during the period from January 2015 to June 2015 were included in the study. The Vitek-2 Compact machine was validated using the standard strains as per the manufacturer’s instructions. The isolates were processed as per the Manufacturer’s instructions for Identification and Antimicrobial Sensitivity Testing (AST).

Results: Out of the 186 strains, 50 strains were isolated from tracheal aspirate, 47 from pus/wound infections, 43 from blood cultures, 25 from urine, 20 from sputum and one from central line tip. The VITEK-2 compact system identified all the strains with a level of 95-99% probability. Most of the strains were identified as Pseudomonas aeruginosa followed by Acientobacter baumannii. Pseudomonas aeruginosa strains were most susceptible to Meropenem (72%) and least susceptible to Cefuroxime and Trimethoprim/Sulfamethoxazole (0%) while Sphingomonas paucimobilis showed resistance to all the antibiotics tested.

Conclusions: Care in detection, evaluation of effective antibiotic options, and judicious use of antibiotics by instituting antibiotic policy for combination therapy and rigorous infection control measures will help us to fight against these multidrug resistant NFGNB during the effective management of patients.



NFGNB, VITEK-2 Compact, Drug resistance, Identification

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