scholarly journals Evolution of Rifampin Resistance in Escherichia coli and Mycobacterium smegmatis Due to Substandard Drugs

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Zohar B. Weinstein ◽  
Muhammad H. Zaman
Keyword(s):  
Escherichia Coli ◽  
Mycobacterium Smegmatis ◽  
Degradation Products ◽  
Treatment Options ◽  
Poor Quality ◽  
Cross Resistance ◽  
Standard Drug ◽  
Content Type ◽  
Drug Degradation ◽  
Rifampin Resistance

ABSTRACT Poor-quality medicines undermine the treatment of infectious diseases, such as tuberculosis, which require months of treatment with rifampin and other drugs. Rifampin resistance is a critical concern for tuberculosis treatment. While subtherapeutic doses of medicine are known to select for antibiotic resistance, the effect of drug degradation products on the evolution of resistance is unknown. Here, we demonstrate that substandard drugs that contain degraded active pharmaceutical ingredients select for gene alterations that confer resistance to standard drugs. We generated drug-resistant Escherichia coli and Mycobacterium smegmatis strains by serially culturing bacteria in the presence of the rifampin degradation product rifampin quinone. We conducted Sanger sequencing to identify mutations in rifampin-resistant populations. Strains resistant to rifampin quinone developed cross-resistance to the standard drug rifampin, with some populations showing no growth inhibition at maximum concentrations of rifampin. Sequencing of the rifampin quinone-treated strains indicated that they acquired mutations in the DNA-dependent RNA polymerase B subunit. These mutations were localized in the rifampin resistance-determining region (RRDR), consistent with other reports of rifampin-resistant E. coli and mycobacteria. Rifampin quinone-treated mycobacteria also had cross-resistance to other rifamycin class drugs, including rifabutin and rifapentine. Our results strongly suggest that substandard drugs not only hinder individual patient outcomes but also restrict future treatment options by actively contributing to the development of resistance to standard medicines.

scholarly journals Short- and Long-Term Transcriptomic Responses of Escherichia coli to Biocides: a Systems Analysis

2020 ◽  
Vol 86 (14) ◽  
Author(s):  
Beatriz Merchel Piovesan Pereira ◽  
Xiaokang Wang ◽  
Ilias Tagkopoulos
Keyword(s):  
Escherichia Coli ◽  
Stress Response ◽  
Stress Responses ◽  
Zinc Homeostasis ◽  
Cross Resistance ◽  
Transcriptional Responses ◽  
Systematic Analysis ◽  
Content Type ◽  
Short Term Exposure

ABSTRACT The mechanisms of the bacterial response to biocides are poorly understood, despite their broad application. To identify the genetic basis and pathways implicated in the biocide stress response, we exposed Escherichia coli populations to 10 ubiquitous biocides. By comparing the transcriptional responses between a short-term exposure (30 min) and a long-term exposure (8 to 12 h) to biocide stress, we established the common gene and pathway clusters that are implicated in general and biocide-specific stress responses. Our analysis revealed a temporal choreography, starting from the upregulation of chaperones to the subsequent repression of motility and chemotaxis pathways and the induction of an anaerobic pool of enzymes and biofilm regulators. A systematic analysis of the transcriptional data identified a zur-regulated gene cluster to be highly active in the stress response against sodium hypochlorite and peracetic acid, presenting a link between the biocide stress response and zinc homeostasis. Susceptibility assays with knockout mutants further validated our findings and provide clear targets for downstream investigation of the implicated mechanisms of action. IMPORTANCE Antiseptics and disinfectant products are of great importance to control and eliminate pathogens, especially in settings such as hospitals and the food industry. Such products are widely distributed and frequently poorly regulated. Occasional outbreaks have been associated with microbes resistant to such compounds, and researchers have indicated potential cross-resistance with antibiotics. Despite that, there are many gaps in knowledge about the bacterial stress response and the mechanisms of microbial resistance to antiseptics and disinfectants. We investigated the stress response of the bacterium Escherichia coli to 10 common disinfectant and antiseptic chemicals to shed light on the potential mechanisms of tolerance to such compounds.

scholarly journals Effect of Exposure to Chlorhexidine Residues at “During Use” Concentrations on Antimicrobial Susceptibility Profile, Efflux, Conjugative Plasmid Transfer, and Metabolism of Escherichia coli

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
R. Wesgate ◽  
S. Fanning ◽  
Y. Hu ◽  
J.-Y. Maillard
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Metabolic Regulation ◽  
Conjugative Plasmid ◽  
Metabolic Phenotype ◽  
Cross Resistance ◽  
Content Type ◽  
Phenotypic Microarray ◽  
The Impact

ABSTRACT There is no standardized protocol to predict the concentration levels of microbicides that are left on surfaces as a result of the use of these products, and there is no standardized method to predict the potential risk that such levels pose to emerging antibacterial resistance. The ability to distinguish between selection and adaption processes for antimicrobial resistance in bacteria and the impact of different concentrations of microbicide exposure have not been fully investigated to date. This study considers the effect of exposure to a low concentration of chlorhexidine digluconate (CHX) on selected phenotypes of Escherichia coli and relates the findings to the risk of emerging antimicrobial resistance. A concentration of 0.006 mg/ml CHX is a realistic “during use” exposure concentration measured on surfaces. At this concentration, it was possible for CHX-susceptible bacteria to survive, adapt through metabolic alterations, exhibit a transient decrease in antimicrobial susceptibility, and express stable clinical cross-resistance to front-line antibiotics. Efflux activity was present naturally in tested isolates, and it increased in the presence of 0.00005 mg/ml CHX but ceased with 0.002 mg/ml CHX. Phenotypic microarray assays highlighted a difference in metabolic regulation at 0.00005 mg/ml and 0.002 mg/ml CHX; more changes occurred after growth with the latter concentration. Metabolic phenotype changes were observed for substrates involved with the metabolism of some amino acids, cofactors, and secondary metabolites. It was possible for one isolate to continue transferring ampicillin resistance in the presence of 0.00005 mg/ml CHX, whilst 0.002 mg/ml CHX prevented conjugative transfer. In conclusion, E. coli phenotype responses to CHX exposure are concentration dependent, with realistic residual CHX concentrations resulting in stable clinical cross-resistance to antibiotics.

scholarly journals Arr-cb Is a Rifampin Resistance Determinant Found Active or Cryptic in Clostridiumbolteae Strains

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Jean-Christophe Marvaud ◽  
Thierry Lambert
Keyword(s):  
Escherichia Coli ◽  
Gut Microbiota ◽  
Reverse Transcription ◽  
Recent Analysis ◽  
Pcr Analysis ◽  
Directed Mutagenesis ◽  
Human Gut ◽  
Content Type ◽  
Reverse Transcription Pcr ◽  
Rifampin Resistance

ABSTRACT Clostridium bolteae, which belongs to the Clostridium clostridioforme complex, is a member of the human gut microbiota. Recent analysis of seven genomes of C. bolteae revealed the presence of an arr-like gene. Among these strains, only 90A7 was found to be resistant to rifampin in the absence of alteration of RpoB. Cloning of arr-cb from 90A7 in Escherichia coli combined with directed mutagenesis demonstrated that Arr-cb was functional but that a Q127→R variant present in 90A9 and 90B3 was inactive. Quantitative reverse transcription-PCR analysis indicated that arr-cb was silent in the four remaining strains because of defective transcription. Thus, two independent mechanisms can make the probably intrinsic arr-cb gene of C. bolteae cryptic.

scholarly journals What Is the Appropriate Meropenem MIC for Screening of Carbapenemase-Producing Enterobacteriaceae in Low-Prevalence Settings?

2015 ◽  
Vol 60 (3) ◽  
pp. 1556-1559 ◽  
Author(s):  
Ramzi Fattouh ◽  
Nathalie Tijet ◽  
Allison McGeer ◽  
Susan M. Poutanen ◽  
Roberto G. Melano ◽  
...  
Keyword(s):  
Public Health ◽  
Escherichia Coli ◽  
Treatment Options ◽  
Large Set ◽  
Wild Type ◽  
Content Type ◽  
The Public ◽  
E Coli ◽  
Low Prevalence ◽  
Screening Approaches

Infection with carbapenemase-producingEnterobacteriaceae(CPE) has been shown to cause significant illness among hospitalized patients. Given the paucity of treatment options, there is a critical need to stop the spread of CPE. However, screening for the presence of CPE in laboratory settings has been challenging. In order to assess the effectiveness of current CPE detection guidelines, we analyzed the meropenem MIC distribution for a large set of clinicalEnterobacteriaceaeisolates. A total of 1,022 isolates submitted to the Public Health Ontario Laboratories (PHOL) from January 2011 to March 2014 were examined. Only isolates displaying a meropenem or ertapenem MIC of ≥0.25 or ≥1 μg/ml, respectively, were included. Carbapenemase-positive isolates were identified by multiplex PCR. We identified 189 isolates positive for carbapenemases, which primarily comprised NDM, KPC, and OXA-48-like carbapenemases, and these isolates were largelyKlebsiellaspp.,Escherichia coli, andEnterobacterspp. Interestingly, 14 to 20% of these isolates displayed meropenem MICs within the susceptible range on the basis of CLSI and EUCAST breakpoint interpretive criteria. While the majority of meropenem-susceptible CPE isolates were observed to beE. coli, meropenem susceptibility was not exclusive to any one species/genus or carbapenemase type. Application of CLSI screening recommendations captured only 86% of carbapenemase-producing isolates, whereas application of EUCAST recommendations detected 98.4% of CPE isolates. In a region with a low carbapenemase prevalence, meropenem-based screening approaches require a cutoff MIC near the epidemiological wild-type threshold in order to achieve nearly optimal CPE identification.

scholarly journals Vitamin K Analogs Influence the Growth and Virulence Potential of Enterohemorrhagic Escherichia coli

2020 ◽  
Vol 86 (24) ◽  
Author(s):  
Anne Kijewski ◽  
Ingun Lund Witsø ◽  
Hildegunn Iversen ◽  
Helene Thorsen Rønning ◽  
Trine L'Abée-Lund ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Vitamin K ◽  
Bacterial Growth ◽  
Shiga Toxin ◽  
Treatment Options ◽  
Inhibitory Effect ◽  
Enterohemorrhagic Escherichia Coli ◽  
Lytic Cycle ◽  
Content Type ◽  
Negative Effect

ABSTRACT Enterohemorrhagic Escherichia coli (EHEC) causes serious foodborne disease worldwide. It produces the very potent Shiga toxin 2 (Stx2). The Stx2-encoding genes are located on a prophage, and production of the toxin is linked to the synthesis of Stx phages. There is, currently, no good treatment for EHEC infections, as antibiotics may trigger lytic cycle activation of the phages and increased Stx production. This study addresses how four analogs of vitamin K, phylloquinone (K1), menaquinone (K2), menadione (K3), and menadione sodium bisulfite (MSB), influence growth, Stx2-converting phage synthesis, and Stx2 production by the EHEC O157:H7 strain EDL933. Menadione and MSB conferred a concentration-dependent negative effect on bacterial growth, while phylloquinone or menaquinone had little and no effect on bacterial growth, respectively. All four vitamin K analogs affected Stx2 phage production negatively in uninduced cultures and in cultures induced with either hydrogen peroxide (H2O2), ciprofloxacin, or mitomycin C. Menadione and MSB reduced Stx2 production in cultures induced with either H2O2 or ciprofloxacin. MSB also had a negative effect on Stx2 production in two other EHEC isolates tested. Phylloquinone and menaquinone had, on the other hand, variable and concentration-dependent effects on Stx2 production. MSB, which conferred the strongest inhibitory effect on both Stx2 phage and Stx2 production, improved the growth of EHEC in the presence of H2O2 and ciprofloxacin, which could be explained by the reduced uptake of ciprofloxacin into the bacterial cell. Together, the data suggest that vitamin K analogs have a growth- and potential virulence-reducing effect on EHEC, which could be of therapeutic interest. IMPORTANCE Enterohemorrhagic E. coli (EHEC) can cause serious illness and deaths in humans by producing toxins that can severely damage our intestines and kidneys. There is currently no optimal treatment for EHEC infections, as antibiotics can worsen disease development. Consequently, the need for new treatment options is urgent. Environmental factors in our intestines can affect the virulence of EHEC and help our bodies fight EHEC infections. The ruminant intestine, the main reservoir for EHEC, contains high levels of vitamin K, but the levels are variable in humans. This study shows that vitamin K analogs can inhibit the growth of EHEC and/or production of its main virulence factor, the Shiga toxin. They may also inhibit the spreading of the Shiga toxin encoding bacteriophage. Our findings indicate that vitamin K analogs have the potential to suppress the development of serious disease caused by EHEC.

scholarly journals Polymorphic Variation in Susceptibility and Metabolism of Triclosan-Resistant Mutants of Escherichia coli and Klebsiella pneumoniae Clinical Strains Obtained after Exposure to Biocides and Antibiotics

2015 ◽  
Vol 59 (6) ◽  
pp. 3413-3423 ◽  
Author(s):  
Tânia Curiao ◽  
Emmanuela Marchi ◽  
Carlo Viti ◽  
Marco R. Oggioni ◽  
Fernando Baquero ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Klebsiella Pneumoniae ◽  
Antimicrobial Susceptibility ◽  
Cross Resistance ◽  
Fitness Costs ◽  
Content Type ◽  
Relative Growth Rates ◽  
Global Regulators ◽  
E Coli ◽  
Reverse Transcription Pcr

ABSTRACTExposure to biocides may result in cross-resistance to other antimicrobials. Changes in biocide and antibiotic susceptibilities, metabolism, and fitness costs were studied here in biocide-selectedEscherichia coliandKlebsiella pneumoniaemutants.E. coliandK. pneumoniaemutants with various degrees of triclosan susceptibility were obtained after exposure to triclosan (TRI), benzalkonium chloride (BKC), chlorhexidine (CHX) or sodium hypochlorite (SHC), and ampicillin or ciprofloxacin. Alterations in antimicrobial susceptibility and metabolism in mutants were tested using Phenotype MicroArrays. The expression of AcrAB pump and global regulators (SoxR, MarA, and RamA) was measured by quantitative reverse transcription-PCR (qRT-PCR), and the central part of thefabIgene was sequenced. The fitness costs of resistance were assessed by a comparison of relative growth rates. Triclosan-resistant (TRIr) and triclosan-hypersusceptible (TRIhs) mutants ofE. coliandK. pneumoniaewere obtained after selection with biocides and/or antibiotics.E. coliTRIrmutants, including those with mutations in thefabIgene or in the expression ofacrB,acrF, andmarA, exhibited changes in susceptibility to TRI, CHX, and antibiotics. TRIrmutants for which the TRI MIC was high presented improved metabolism of carboxylic acids, amino acids, and carbohydrates. In TRIrmutants, resistance to one antimicrobial provoked hypersusceptibility to another one(s). TRIrmutants had fitness costs, particularlymarA-overexpressing (E. coli) orramA-overexpressing (K. pneumoniae) mutants. TRI, BKC, and CIP exposure frequently yielded TRIrmutants exhibiting alterations in AraC-like global regulators (MarA, SoxR, and RamA), AcrAB-TolC, and/or FabI, and influencing antimicrobial susceptibility, fitness, and metabolism. These various phenotypes suggest a trade-off of different selective processes shaping the evolution toward antibiotic/biocide resistance and influencing other adaptive traits.

scholarly journals No Decrease in Susceptibility to NVC-422 in Multiple-Passage Studies with Methicillin-Resistant Staphylococcus aureus, S. aureus, Pseudomonas aeruginosa, and Escherichia coli

2012 ◽  
Vol 56 (5) ◽  
pp. 2753-2755 ◽  
Author(s):  
Louisa D'Lima ◽  
Lisa Friedman ◽  
Lu Wang ◽  
Ping Xu ◽  
Mark Anderson ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Fusidic Acid ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Cross Resistance ◽  
Methicillin Resistant ◽  
Content Type ◽  
E Coli ◽  
Resistant Strains

ABSTRACTTwenty-five serial passages ofEscherichia coli,Pseudomonas aeruginosa, andStaphylococcus aureusand 50 passages of methicillin-resistantStaphylococcus aureusresulted in no significant increase in NVC-422 MICs, while ciprofloxacin MICs increased 256-fold forE. coliand 32-fold forP. aeruginosaandS. aureus. Mupirocin, fusidic acid, and retapamulin MICs for MRSA increased 64-, 256-, and 16-fold, respectively. No cross-resistance to NVC-422 was observed with mupirocin-, fusidic acid-, and retapamulin-resistant strains.

scholarly journals Biocide Exposure Induces Changes in Susceptibility, Pathogenicity, and Biofilm Formation in Uropathogenic Escherichia coli

2019 ◽  
Vol 63 (3) ◽  
Author(s):  
E. L. Henly ◽  
J. A. R. Dowling ◽  
J. B. Maingay ◽  
M. M. Lacey ◽  
T. J. Smith ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Silver Nitrate ◽  
Biofilm Formation ◽  
Galleria Mellonella ◽  
Bacterial Colonization ◽  
Fibroblast Cell ◽  
Cross Resistance ◽  
Coating Agent ◽  
Content Type

ABSTRACT Uropathogenic Escherichia coli (UPEC) is a frequent cause of catheter-associated urinary tract infection (CAUTI). Biocides have been incorporated into catheter coatings to inhibit bacterial colonization while, ideally, exhibiting low cytotoxicity and mitigating the selection of resistant bacterial populations. We compared the effects of long-term biocide exposure on susceptibility, biofilm formation, and relative pathogenicity in eight UPEC isolates. MICs, minimum bactericidal concentrations (MBCs), minimum biofilm eradication concentrations (MBECs), and antibiotic susceptibilities were determined before and after long-term exposure to triclosan, polyhexamethylene biguanide (PHMB), benzalkonium chloride (BAC), and silver nitrate. Biofilm formation was quantified using a crystal violet assay, and relative pathogenicity was assessed via a Galleria mellonella waxworm model. Cytotoxicity and the resulting biocompatibility index values were determined by use of an L929 murine fibroblast cell line. Biocide exposure resulted in multiple decreases in biocide susceptibility in planktonic and biofilm-associated UPEC. Triclosan exposure induced the largest frequency and magnitude of susceptibility decreases at the MIC, MBC, and MBEC, which correlated with an increase in biofilm biomass in all isolates. Induction of antibiotic cross-resistance occurred in 6/84 possible combinations of bacteria, biocide, and antibiotic. Relative pathogenicity significantly decreased after triclosan exposure (5/8 isolates), increased after silver nitrate exposure (2/8 isolates), and varied between isolates for PHMB and BAC. The biocompatibility index ranked the antiseptic potential as PHMB > triclosan > BAC > silver nitrate. Biocide exposure in UPEC may lead to reductions in biocide and antibiotic susceptibility, changes in biofilm formation, and alterations in relative pathogenicity. These data indicate the multiple consequences of biocide adaptation that should be considered when selecting an anti-infective catheter-coating agent.

scholarly journals Dissemination of NDM Metallo-β-Lactamase Genes among Clinical Isolates of Enterobacteriaceae Collected during the SMART Global Surveillance Study from 2008 to 2012

2014 ◽  
Vol 59 (2) ◽  
pp. 826-830 ◽  
Author(s):  
D. Biedenbach ◽  
S. Bouchillon ◽  
M. Hackel ◽  
D. Hoban ◽  
K. Kazmierczak ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Bacterial Species ◽  
Treatment Options ◽  
Surveillance Study ◽  
Cross Resistance ◽  
New Delhi ◽  
Content Type ◽  
Class B ◽  
Tract Infections ◽  
Inhibitor Combination

ABSTRACTThe prevalence of carbapenemase enzymes continues to increase. Among the Ambler class B enzymes is the New Delhi metallo-β-lactamase (NDM). This particular enzyme is capable of hydrolyzing nearly all β-lactam antimicrobial agents and has spread rapidly, becoming a global problem. Therapeutic treatment options for patients infected with isolates which produce this enzyme are difficult to manage, as cross-resistance to other antimicrobial classes is common. The Study for Monitoring Antimicrobial Resistance Trends (SMART) is a global surveillance study evaluating the antimicrobial susceptibilities of numerous Gram-negative bacterial species recovered from people with intra-abdominal and urinary tract infections. The Clinical and Laboratory Standards Institute methods and a molecular analysis identified 134 isolates ofEnterobacteriaceae(nine species) and oneAcinetobactersp. withblaNDMgenes. These isolates were collected in nine countries, and >95% of the isolates possessed the NDM-1 variant. The MIC90values were >4 mg/liter and >8 mg/liter for ertapenem and imipenem, respectively. No tested β-lactam or β-lactamase inhibitor combination had activity against these isolates. Resistance to amikacin (79.9%) and levofloxacin (82.8%) was common. Nearly all the isolates encoded additional enzymes, including AmpC cephalosporinases and extended-spectrum β-lactamases. There is an urgent need for infection control and continued global monitoring of isolates which harbor the NDM enzyme, as evidenced by recent outbreaks.

scholarly journals Mutation Analysis of MycobacterialrpoBGenes and Rifampin Resistance Using Recombinant Mycobacterium smegmatis

2012 ◽  
Vol 56 (4) ◽  
pp. 2008-2013 ◽  
Author(s):  
Noboru Nakata ◽  
Masanori Kai ◽  
Masahiko Makino
Keyword(s):  
Mycobacterium Smegmatis ◽  
Clinical Isolates ◽  
Recombinant Bacteria ◽  
Gene Encoding ◽  
Content Type ◽  
Rifampin Resistance ◽  
Recombinant Mycobacterium Smegmatis ◽  
The Relationship ◽  
Major Drug

ABSTRACTRifampin is a major drug used to treat leprosy and tuberculosis. The rifampin resistance ofMycobacterium lepraeandMycobacterium tuberculosisresults from a mutation in therpoBgene, encoding the β subunit of RNA polymerase. A method for the molecular determination of rifampin resistance in these two mycobacteria would be clinically valuable, but the relationship between the mutations and susceptibility to rifampin must be clarified before its use. Analyses of mutations responsible for rifampin resistance using clinical isolates present some limitations. Each clinical isolate has its own genetic variations in some loci other thanrpoB, which might affect rifampin susceptibility. For this study, we constructed recombinant strains ofMycobacterium smegmatiscarrying theM. lepraeorM. tuberculosis rpoBgene with or without mutation and disrupted their ownrpoBgenes on the chromosome. The rifampin and rifabutin susceptibilities of the recombinant bacteria were measured to examine the influence of the mutations. The results confirmed that several mutations detected in clinical isolates of these two pathogenic mycobacteria can confer rifampin resistance, but they also suggested that some mutations detected inM. lepraeisolates or rifampin-resistantM. tuberculosisisolates are not involved in rifampin resistance.

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