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. 2019 Feb;149(2):185-191.
doi: 10.4103/ijmr.IJMR_2086_17.

Susceptibility profile, resistance mechanisms & efficacy ratios of fosfomycin, nitrofurantoin & colistin for carbapenem-resistant Enterobacteriaceae causing urinary tract infections

Anushree Ulhas Amladi  1 , Baby Abirami  1 , S Manjula Devi  1 , Thambu David Sudarsanam  2 , Subramani Kandasamy  3 , Nitin Kekre  4 , Balaji Veeraraghavan  1 , Rani Diana Sahni  1
Affiliations

Susceptibility profile, resistance mechanisms & efficacy ratios of fosfomycin, nitrofurantoin & colistin for carbapenem-resistant Enterobacteriaceae causing urinary tract infections

Anushree Ulhas Amladi et al. Indian J Med Res. 2019 Feb.

Abstract

Background & objectives: The escalation in carbapenem resistance among Enterobacteriaceae has resulted in a lack of effective therapeutic alternatives. Older antimicrobials, fosfomycin, nitrofurantoin and colistin for urinary tract infections (UTIs) caused by carbapenem-resistant Enterobacteriaceae (CRE) may be effective treatment options. The objectives of this study were to evaluate the utility of fosfomycin, nitrofurantoin and colistin in treating UTI caused by CRE and molecular characterization of the plasmid-mediated carbapenem resistance mechanisms.

Methods: Consecutive, non-duplicate isolates of CR Escherichia coli and Klebsiella spp. from urine cultures were included (n=150). Minimum inhibitory concentrations (MIC) were determined by E-test (fosfomycin and nitrofurantoin) and broth microdilution (colistin). Efficacy ratios were derived by dividing susceptibility breakpoints by observed MIC values of the drugs for the isolates. Isolates were screened for genes coding for carbapenemases using multiplex PCR. Fosfomycin, nitrofurantoin and colistin-resistant isolates were screened for plasmid-borne resistance genes fos A3, oqx AB and mcr-1, respectively using PCR.

Results: Among E. coli, 98.9, 56 and 95 per cent isolates were susceptible to fosfomycin, nitrofurantoin and colistin, respectively, while 94 and 85 per cent of Klebsiella spp. were susceptible to fosfomycin and colistin, respectively. The efficacy ratios indicated fosfomycin as the drug of choice for UTI caused by CR E. coli and Klebsiella spp., followed by colistin. The blaNDM gene was most common, followed by blaOXA48-like. Plasmid-borne genes encoding resistance to fosfomycin, nitrofurantoin and colistin were absent.

Interpretation & conclusions: With increasing resistance against the current treatment options, older drugs may emerge as effective options. Molecular screening of resistant isolates is essential to prevent the spread of plasmid-borne resistance against these drugs.

Keywords: Carbapenem-resistant; Enterobacteriaceae; colistin; fosfomycin; nitrofurantoin; therapeutic efficacy.

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Conflict of interest statement

None

Figures

Fig. 1
Fig. 1
Comparison of efficacy ratio of fosfomycin, nitrofurantoin and colistin for E.coli.
Fig. 2
Fig. 2
Comparison of the efficacy ratio of fosfomycin and colistin for Klebsiella spp.
See this image and copyright information in PMC

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References

    1. Stamm WE, Norrby SR. Urinary tract infections: Disease panorama and challenges. J Infect Dis. 2001;183(Suppl 1):S1–4. - PubMed
    1. Cassir N, Rolain JM, Brouqui P. A new strategy to fight antimicrobial resistance: The revival of old antibiotics. Front Microbiol. 2014;5:551. - PMC - PubMed
    1. Theuretzbacher U, Van Bambeke F, Cantón R, Giske CG, Mouton JW, Nation RL, et al. Reviving old antibiotics. J Antimicrob Chemother. 2015;70:2177–81. - PubMed
    1. Ho PL, Ng KY, Lo WU, Law PY, Lai EL, Wang Y, et al. Plasmid-mediated oqxAB is an important mechanism for nitrofurantoin resistance in Escherichia coli. Antimicrob Agents Chemother. 2016;60:537–43. - PMC - PubMed
    1. Liu YY, Wang Y, Walsh TR, Yi LX, Zhang R, Spencer J, et al. Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: A microbiological and molecular biological study. Lancet Infect Dis. 2016;16:161–8. - PubMed

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