Discovery and Characterization of a Nitroreductase Capable of Conferring Bacterial Resistance to Chloramphenicol

Crofts, Terence Spencer; Sontha, Pratyush; King, Amber O.; Wang, Bin; Biddy, Brent A.; Zanolli, Nicole; Gaumnitz, John; Dantas, Gautam

doi:10.1016/j.chembiol.2019.01.007

Cited by 57 publications

(85 citation statements)

References 58 publications

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“…This might confer a selective advantage via a higher potential to recycle NAD(P) as electron acceptors for the (fermentative) energy and intermediary metabolism, or via the possibility to inactivate toxic xenobiotics produced by gut commensal microorganisms. Recently, similar findings were published concerning the Haemophilus influenzae nitroreductase NfsB reducing and thereby inactivating chloramphenicol (Crofts et al, ). On the other hand, the reduction in nitro compounds to toxic intermediates renders organisms expressing such nitroreductases susceptible to nitro drugs and therefore constitutes a selective disadvantage.…”

Section: Discussionsupporting

confidence: 68%

Nitroreductases of bacterial origin in Giardia lamblia: Potential role in detoxification of xenobiotics

Müller

2019

MicrobiologyOpen

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The anaerobic parasite Giardia lamblia, causative agent of persistent diarrhea, contains a family of nitroreductase genes most likely acquired by lateral transfer from anaerobic bacteria or archaebacteria. Two of these nitroreductases, containing a ferredoxin domain at their N‐terminus, NR1, and NR2, have been characterized previously. Here, we present the characterization of a third member of this family, NR3. In functional assays, recombinant NR1 and NR3 reduced quinones like menadione and the antibiotic tetracycline, and—to much lesser extents—the nitro compound dinitrotoluene. Conversely, recombinant NR2 had no activity on tetracycline. Escherichia coli expressing NR3 were less susceptible to tetracycline, but more susceptible to the nitro compound metronidazole under semi‐aerobic growth conditions. G. lamblia overexpressing NR1 and NR3, but not lines overexpressing NR2, are more susceptible to the nitro drug nitazoxanide. These findings suggest that NR3 is an active quinone reductase with a mode of action similar to NR1, but different from NR2. The biological function of this family of enzymes may reside in the use of xenobiotics as final electron acceptors. Thereby, these enzymes may provide at least two evolutionary advantages namely a higher potential to recycle NAD(P) as electron acceptors for the (fermentative) energy and intermediary metabolism, and the possibility to inactivate toxic xenobiotics produced by microorganisms living in concurrence inside the intestinal habitat.

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Section: Discussionsupporting

confidence: 68%

Nitroreductases of bacterial origin in Giardia lamblia: Potential role in detoxification of xenobiotics

Müller

2019

MicrobiologyOpen

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“…Resistance to chloramphenicol was reported in five STEC strains, being different from that reported for industrialized species in Chile, where AMR was detected for a wider variety of drugs at phenotypical analysis ( 47 ). Resistance to the phenicols is mainly due to the presence of cat genes, encoding for chloramphenicol acetyltransferases, specific to chloramphenicol, or to the presence of cml genes, encoding for efflux pumps, among other mechanism, such as nfs B nitroreductase expression ( 81 ).…”

Section: Discussionmentioning

confidence: 99%

Antimicrobial Usage Factors and Resistance Profiles of Shiga Toxin-Producing Escherichia coli in Backyard Production Systems From Central Chile

et al. 2021

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Shiga toxin-producing Escherichia coli (STEC) is a zoonotic pathogen and important cause of foodborne disease worldwide. Many animal species in backyard production systems (BPS) harbor STEC, systems characterized by low biosecurity and technification. No information is reported on STEC circulation, antimicrobial resistance (AMR) and potential drivers of antimicrobial usage in Chilean BPS, increasing the risk of maintenance and transmission of zoonotic pathogens and AMR generation. Thus, the aim of this study was to characterize phenotypic and genotypic AMR and to study the epidemiology of STEC isolated in BPS from Metropolitana region, Chile. A total of 85 BPS were sampled. Minimal inhibitory concentration and whole genome sequencing was assessed in 10 STEC strain isolated from BPS. All strains were cephalexin-resistant (100%, n = 10), and five strains were resistant to chloramphenicol (50%). The most frequent serotype was O113:H21 (40%), followed by O76:H19 (40%), O91:H14 (10%), and O130:H11 (10%). The stx1 type was detected in all isolated strains, while stx2 was only detected in two strains. The Stx subtype most frequently detected was stx1c (80%), followed by stx1a (20%), stx2b (10%), and stx2d (10%). All strains harbored chromosomal blaAmpC. Principal component analysis shows that BPS size, number of cattle, pet and horse, and elevation act as driver of antimicrobial usage. Logistic multivariable regression shows that recognition of diseases in animals (p = 0.038; OR = 9.382; 95% CI: 1.138–77.345), neighboring poultry and/or swine BPS (p = 0.006; OR = 10.564; 95% CI: 1.996–55.894), visit of Veterinary Officials (p = 0.010; OR = 76.178; 95% CI: 2.860–2029.315) and close contact between animal species in the BPS (p = 0.021; OR = 9.030; 95% CI: 1.385–58.888) increase significantly the risk of antimicrobial use in BPS. This is the first evidence of STEC strains circulating in BPS in Chile, exhibiting phenotypic AMR, representing a threat for animal and public health. Additionally, we identified factors acting as drivers for antimicrobial usage in BPS, highlighting the importance of integration of these populations into surveillance and education programs to tackle the potential development of antimicrobial resistance and therefore the risk for ecosystemic health.

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“…NfsB_Ec has received near-exclusive attention as a prodrug-converting NTR for both cancer gene therapy and targeted cell ablation applications 1 . However, recent evidence suggests "NTR 1.0" is a relatively inefficient NTR compared to orthologous enzymes 23,33,34 . In particular, we showed that active site residues F70 and F108 impede activity with the 5-nitroimidazole PET probe SN33623 and that rational substitution of these residues yielded generic improvements in 5-nitroimidazole reduction 23 .…”

Section: Discussionmentioning

confidence: 99%

NTR 2.0: a rationally-engineered prodrug converting enzyme with substantially enhanced efficacy for targeted cell ablation

Sharrock

Mulligan

Hall

et al. 2020

Preprint

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Heterologously-expressed bacterial nitroreductase (NTR) enzymes sensitize eukaryotic cells to prodrugs such as metronidazole (MTZ), enabling selective cell ablation paradigms that have expanded studies of cell function and regeneration in vertebrate systems. However, first-generation NTRs require confoundingly toxic prodrug treatments (e.g. 10 mM MTZ) and some cell types have proven resistant. We used rational engineering and cross-species screening to develop a NTR variant, NTR 2.0, which exhibits ~100-fold improvement in MTZ-mediated cell-specific ablation efficacy. Toxicity tests in zebrafish showed no deleterious effects of prolonged MTZ treatments of ≤1 mM. NTR 2.0 therefore enables sustained cell loss paradigms and ablation of previously resistant cell types. These properties permit enhanced interrogations of cell function, extended challenges to the regenerative capacities of discrete stem cell niches, and enable modeling of chronic degenerative diseases. Accordingly, we have created a series of bipartite transgenic resources to facilitate dissemination of NTR 2.0 to the research community.

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Discovery and Characterization of a Nitroreductase Capable of Conferring Bacterial Resistance to Chloramphenicol

Cited by 57 publications

References 58 publications

Nitroreductases of bacterial origin in Giardia lamblia: Potential role in detoxification of xenobiotics

Nitroreductases of bacterial origin in Giardia lamblia: Potential role in detoxification of xenobiotics

Antimicrobial Usage Factors and Resistance Profiles of Shiga Toxin-Producing Escherichia coli in Backyard Production Systems From Central Chile

NTR 2.0: a rationally-engineered prodrug converting enzyme with substantially enhanced efficacy for targeted cell ablation

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