Revisiting Nitrofurantoin for Vancomycin Resistant Enterococci

J Clin Diagn Res. 2017 Jun;11(6):DC19-DC22. doi: 10.7860/JCDR/2017/25140.10140. Epub 2017 Jun 1.

Abstract

Introduction: Enterococcal infection has emerged as a major therapeutic challenge. Emergence of High Level Aminoglycoside Resistance (HLAR) and Vancomycin-Resistant Enterococcus (VRE) has further limited the drug therapy in enterococcal infections. However, nitrofuratoin being an old drug reported to have less resistance in comparison to the other classes of antimicrobial agents.

Aim: To detect susceptibility of nitrofurantoin against VRE isolates from Urinary Tract Infection (UTI) of outdoor and indoor patient departments.

Materials and methods: An observational study was carried out at a tertiary care hospital in New Delhi over a period of six months (from November 2015 to April 2016). A total of 14,714 urine samples were collected and processed from the patients symptomatic for UTI. The enterococcal isolates were identified and confirmed by standard phenotypic tests. The antimicrobial susceptibility tests of isolated organisms were performed by Kirby-Bauer Disc Diffusion Method as per Clinical and Laboratory Standards Institute (CLSI) 2015 guidelines. The Wilcoxon rank-sum (Mann-Whitney) test was used to compare continuous variables. Chi-square or Fisher's exact tests were used to compare categorical variables. p<0.05 was considered as significant.

Results: A total of 70 enterococci species {Enterococcus faecalis (n=9), Enterococcus faecium, (n=61)} were isolated. Twenty six out of 70 isolates were observed resistant to vancomycin. Among 26 VRE, 21(80.76%) were susceptible to nitrofurantoin. Both the species {E. faecalis (80.32%) and E. faecium (88.8%)} were uniformly susceptible to nitrofurantoin.

Conclusion: Nitrofurantoin has retained antimicrobial efficacy against emerging VRE in vitro and can be used for treatment of enterococcal urinary tract infections.

Keywords: Enterococcus faecalis; Enterococcus faecium; Linezolid; Multiple drug resistance; Urinary tract infection.