DIAGNOSTIC ACCURACY OF IN-HOUSE BIOCHEMICAL TESTING FOR IDENTIFICATION OF ENTEROCOCCUS SPECIES ISOLATED FROM VARIOUS CLINICAL SPECIMENSAGAINST VITEK 2 SYSTEM
Keywords:Enterococcus spp, In-house biochemical testing, Vitek 2 system
Objective: To determine the diagnostic accuracy of in-house biochemical testing for identification of enterococcus species isolated from various clinical specimens against gold standard i.e., automated Vitek 2 system. This study also includes the antimicrobial susceptibility testing of enterococci against various antimicrobials.
Study Design: Cross-sectional comparative study.
Place and Duration of Study: Department of Microbiology, Armed Forces Institute of Pathology, Rawalpindi,
from Apr 2017 to Mar 2018.
Methodology: A total of 218 isolates from various clinical specimens suspected to be Enterococcus spp. were
checked by in-house biochemical testing including bile esculin, 6.5% NaCl and 1% arabinose and results were
compared with Vitek 2 compact system. The frequencies were determined by both systems and antimicrobial susceptibility testing was performed by disk diffusion as per clinical and laboratory standards institute guidelines.
Results: Comparing the results of in-house testing with gold standard i.e., Vitek 2 system, the statistical data was calculated. Sensitivity turned out to be 100%, Specificity was found to be 68.75%. Positive and negative predictive values were 97.58% and 100% respectively. Accuracy turned out to be 97.71%.
Conclusion: The in-house biochemical testing can be quite a useful method for identification of enterococci in
resource-limited settings. However, it requires overight incubation and cannot identify other enterococcal species and non-enterococcal species. Vitek 2 is an automated system that is easy-to-handle, provides a rapid and reasonably accurate identification of enterococci alongwith accurate AST results. Enterococcal isolates from various clinical specimens in our setup showed least resistance to linezolid, followed by teicoplanin and vancomycin. Nitrofurantoin and.............