scholarly journals Unexpected Activity of Oral Fosfomycin against Resistant Strains ofEscherichia coliin Murine Pyelonephritis

2019 ◽  
Vol 63 (8) ◽  
Author(s):  
Annabelle Pourbaix ◽  
François Guérin ◽  
Charles Burdet ◽  
Laurent Massias ◽  
Françoise Chau ◽  
...  
Keyword(s):  
Oral Treatment ◽  
Urine Ph ◽  
Content Type ◽  
Potential Efficacy ◽  
Plasma Concentration Ratio ◽  
Resistant Strains ◽  
Tract Infections ◽  
Lower Urinary

ABSTRACTFosfomycin tromethamine activity is well established for oral treatment of uncomplicated lower urinary tract infections, but little is known about its potential efficacy in pyelonephritis. Ascending pyelonephritis was induced in mice infected with 6 strains ofEscherichia coli(fosfomycin MICs, 1 μg/ml to 256 μg/ml). The urine pH was 4.5 before infection and 5.5 to 6.0 during infection. Animals were treated for 24 h with fosfomycin (100 mg/kg of body weight subcutaneously every 4 h), and the CFU were enumerated in kidneys 24 h after the last fosfomycin injection. Peak (20.5 μg/ml at 1 h) and trough (3.5 μg/ml at 4 h) levels in plasma were comparable to those obtained in humans after an oral dose of 3 g. Fosfomycin treatment significantly reduced the bacterial loads in kidneys (3.65 log10CFU/g [range, 1.83 to 7.03 log10CFU/g] and 1.88 log10CFU/g [range, 1.78 to 5.74 log10CFU/g] in start-of-treatment control mice and treated mice, respectively;P < 10−6). However, this effect was not found to differ across the 6 study strains (P = 0.71) or between the 3 susceptible and the 3 resistant strains (P = 0.09). Three phenomena may contribute to explain this unexpectedin vivoactivity: (i) in mice, the fosfomycin kidney/plasma concentration ratio increased from 1 to 7.8 (95% confidence interval, 5.2, 10.4) within 24 hin vitrowhen the pH decreased to 5, (ii) the fosfomycin MICs for the 3 resistant strains (64 to 256 μg/ml) decreased into the susceptible range (16 to 32 μg/ml), and (iii) maximal growth rates significantly decreased for all strains and were the lowest in urine. These results suggest that local fosfomycin concentrations and physiological conditions may favor fosfomycin activity in pyelonephritis, even against resistant strains.

scholarly journals Unexpected activity of oral fosfomycin against resistant strains ofEscherichia coliin murine pyelonephritis

2019 ◽  
Author(s):  
Annabelle Pourbaix ◽  
François Guérin ◽  
Charles Burdet ◽  
Laurent Massias ◽  
Françoise Chau ◽  
...  
Keyword(s):  
Oral Treatment ◽  
Plasma Concentrations ◽  
Urine Ph ◽  
Physiological Conditions ◽  
Potential Efficacy ◽  
Resistant Strains ◽  
Tract Infections ◽  
Lower Urinary

AbstractFosfomycin-tromethamine activity is well established for oral treatment of uncomplicated lower urinary tract infections but little is known about its potential efficacy in pyelonephritis. Ascending pyelonephritis was induced in mice infected with 6 strains ofEscherichia coli(fosfomycin MICs: 1 μg/ml to 256 μg/ml). Urine pH was 4.5 before infection and 5.5-6.0 during infection. Animals were treated for 24h with fosfomycin (100 mg/kg subcutaneously every 4 hours) and CFU were enumerated in kidneys 24h after the last fosfomycin injection. Peak (20.5 μg/ml at 1h) and trough (3.5 μg/ml at 4h) levels in plasma were comparable to those obtained in human after an oral dose of 3 grams. Fosfomycin treatment significantly reduced bacterial loads in kidneys (3.65 log10CFU/g [min-max=1.83-7.03] and 1.88 log10CFU/g [1.78-5.74] in start-of-treatment control mice and treated mice, respectively,P< 10-6). However, this effect was not found to differ across the 6 study strains (P = 0.71) and between the 3 susceptible and the 3 resistant strains (P=0.09). Three phenomena may contribute to explain this unexpectedin vivoactivity: i) in mice, fosfomycin kidney/plasma concentrations ratio increased from 1 to 7.8 (95% CI, 5.2; 10.4) within 24 hours;in vitro, when pH decreased to 5: (ii) fosfomycin MICs for the 3 resistant strains (64-256 μg/ml) decreased into the susceptible range (16-32 μg/ml) and: iii) maximal growth rates significantly decreased for all strains and were the lowest in urine. These results suggest that local fosfomycin concentrations and physiological conditions may favour fosfomycin activity in pyelonephritis, even against resistant strains.

FimH Antagonists for the Oral Treatment of Urinary Tract Infections: From Design and Synthesis to in Vitro and in Vivo Evaluation

2010 ◽  
Vol 53 (24) ◽  
pp. 8627-8641 ◽  
Author(s):  
Tobias Klein ◽  
Daniela Abgottspon ◽  
Matthias Wittwer ◽  
Said Rabbani ◽  
Janno Herold ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Oral Treatment ◽  
In Vivo Evaluation ◽  
Design And Synthesis ◽  
Tract Infections

scholarly journals Peptidoglycan Sensing Prevents Quiescence and Promotes Quorum-Independent Colony Growth of Uropathogenic Escherichia coli

2020 ◽  
Vol 202 (20) ◽  
Author(s):  
Eric C. DiBiasio ◽  
Hilary J. Ranson ◽  
James R. Johnson ◽  
David C. Rowley ◽  
Paul S. Cohen ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Recurrent Infection ◽  
Colony Growth ◽  
Quiescent State ◽  
Content Type ◽  
Tract Infections

ABSTRACT Uropathogenic Escherichia coli (UPEC) is the leading cause of human urinary tract infections (UTIs), and many patients experience recurrent infection after successful antibiotic treatment. The source of recurrent infections may be persistent bacterial reservoirs in vivo that are in a quiescent state and thus are not susceptible to antibiotics. Here, we show that multiple UPEC strains require a quorum to proliferate in vitro with glucose as the carbon source. At low cell density, the bacteria remain viable but enter a quiescent, nonproliferative state. Of the clinical UPEC isolates tested to date, 35% (51/145) enter this quiescent state, including isolates from the recently emerged, multidrug-resistant pandemic lineage ST131 (i.e., strain JJ1886) and isolates from the classic endemic lineage ST73 (i.e., strain CFT073). Moreover, quorum-dependent UPEC quiescence is prevented and reversed by small-molecule proliferants that stimulate colony formation. These proliferation cues include d-amino acid-containing peptidoglycan (PG) tetra- and pentapeptides, as well as high local concentrations of l-lysine and l-methionine. Peptidoglycan fragments originate from the peptidoglycan layer that supports the bacterial cell wall but are released as bacteria grow. These fragments are detected by a variety of organisms, including human cells, other diverse bacteria, and, as we show here for the first time, UPEC. Together, these results show that for UPEC, (i) sensing of PG stem peptide and uptake of l-lysine modulate the quorum-regulated decision to proliferate and (ii) quiescence can be prevented by both intra- and interspecies PG peptide signaling. IMPORTANCE Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). During pathogenesis, UPEC cells adhere to and infiltrate bladder epithelial cells, where they may form intracellular bacterial communities (IBCs) or enter a nongrowing or slowly growing quiescent state. Here, we show in vitro that UPEC strains at low population density enter a reversible, quiescent state by halting division. Quiescent cells resume proliferation in response to sensing a quorum and detecting external signals, or cues, including peptidoglycan tetra- and pentapeptides.

scholarly journals A Conserved PapB Family Member, TosR, Regulates Expression of the Uropathogenic Escherichia coli RTX Nonfimbrial Adhesin TosA while Conserved LuxR Family Members TosE and TosF Suppress Motility

2014 ◽  
Vol 82 (9) ◽  
pp. 3644-3656 ◽  
Author(s):  
Michael D. Engstrom ◽  
Christopher J. Alteri ◽  
Harry L. T. Mobley
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Virulence Factors ◽  
Upper Urinary Tract ◽  
Host Cells ◽  
Promoter Regions ◽  
Content Type ◽  
Tract Infections

ABSTRACTA heterogeneous subset of extraintestinal pathogenicEscherichia coli(ExPEC) strains, referred to as uropathogenicE. coli(UPEC), causes most uncomplicated urinary tract infections. However, no core set of virulence factors exists among UPEC strains. Instead, the focus of the analysis of urovirulence has shifted to studying broad classes of virulence factors and the interactions between them. For example, the RTX nonfimbrial adhesin TosA mediates adherence to host cells derived from the upper urinary tract. The associatedtosoperon is well expressedin vivobut poorly expressedin vitroand encodes TosCBD, a predicted type 1 secretion system. TosR and TosEF are PapB and LuxR family transcription factors, respectively; however, no role has been assigned to these potential regulators. Thus, the focus of this study was to determine how TosR and TosEF regulatetosAand affect the reciprocal expression of adhesins and flagella. Among a collection of sequenced UPEC strains, 32% (101/317) were found to encode TosA, and nearly all strains (91% [92/101]) simultaneously carried the putative regulatory genes. Deletion oftosRalleviatestosArepression. Thetospromoter was localized upstream oftosRusing transcriptional fusions of putative promoter regions withlacZ. TosR binds to this region, affecting a gel shift. A 100-bp fragment 220 to 319 bp upstream oftosRinhibits binding, suggesting localization of the TosR binding site. TosEF, on the other hand, downmodulate motility when overexpressed by preventing the expression offliC, encoding flagellin. Deletion oftosEFincreased motility. Thus, we present an additional example of the reciprocal control of adherence and motility.

scholarly journals Macrolones Are a Novel Class of Macrolide Antibiotics Active against Key Resistant Respiratory PathogensIn VitroandIn Vivo

2016 ◽  
Vol 60 (9) ◽  
pp. 5337-5348 ◽  
Author(s):  
Hana Čipčić Paljetak ◽  
Donatella Verbanac ◽  
Jasna Padovan ◽  
Miroslava Dominis-Kramarić ◽  
Željko Kelnerić ◽  
...  
Keyword(s):  
Murine Model ◽  
Bacterial Resistance ◽  
Volume Of Distribution ◽  
Macrolide Antibiotics ◽  
Respiratory Pathogens ◽  
Protein Synthesis Inhibitors ◽  
Content Type ◽  
Tract Infections

ABSTRACTAs we face an alarming increase in bacterial resistance to current antibacterial chemotherapeutics, expanding the available therapeutic arsenal in the fight against resistant bacterial pathogens causing respiratory tract infections is of high importance. The antibacterial potency of macrolones, a novel class of macrolide antibiotics, against key respiratory pathogens was evaluatedin vitroandin vivo. MIC values againstStreptococcus pneumoniae,Streptococcus pyogenes,Staphylococcus aureus, andHaemophilus influenzaestrains sensitive to macrolide antibiotics and with defined macrolide resistance mechanisms were determined. The propensity of macrolones to induce the expression of inducibleermgenes was tested by the triple-disk method and incubation in the presence of subinhibitory concentrations of compounds.In vivoefficacy was assessed in a murine model ofS. pneumoniae-induced pneumonia, and pharmacokinetic (PK) profiles in mice were determined. Thein vitroantibacterial profiles of macrolones were superior to those of marketed macrolide antibiotics, including the ketolide telithromycin, and the compounds did not induce the expression of inducibleermgenes. They acted as typical protein synthesis inhibitors in anEscherichia colitranscription/translation assay. Macrolones were characterized by low to moderate systemic clearance, a large volume of distribution, a long half-life, and low oral bioavailability. They were highly efficacious in a murine model of pneumonia after intraperitoneal application even against anS. pneumoniaestrain with constitutive resistance to macrolide-lincosamide-streptogramin B antibiotics. Macrolones are the class of macrolide antibiotics with an outstanding antibacterial profile and reasonable PK parameters resulting in goodin vivoefficacy.

scholarly journals Sontochin as a Guide to the Development of Drugs against Chloroquine-Resistant Malaria

2012 ◽  
Vol 56 (7) ◽  
pp. 3475-3480 ◽  
Author(s):  
Sovitj Pou ◽  
Rolf W. Winter ◽  
Aaron Nilsen ◽  
Jane Xu Kelly ◽  
Yuexin Li ◽  
...  
Keyword(s):  
Multidrug Resistant ◽  
Plasmodium Yoelii ◽  
Significant Activity ◽  
Drug Resistant ◽  
Content Type ◽  
Resistant Strains ◽  
Drug Resistant Strains ◽  
Derivatives Of

ABSTRACTSontochin was the original chloroquine replacement drug, arising from research by Hans Andersag 2 years after chloroquine (known as “resochin” at the time) had been shelved due to the mistaken perception that it was too toxic for human use. We were surprised to find that sontochin, i.e., 3-methyl-chloroquine, retains significant activity against chloroquine-resistant strains ofPlasmodium falciparum in vitro. We prepared derivatives of sontochin, “pharmachins,” with alkyl or aryl substituents at the 3 position and with alterations to the 4-position side chain to enhance activity against drug-resistant strains. Modified with an aryl substituent in the 3 position of the 7-chloro-quinoline ring, Pharmachin 203 (PH-203) exhibits low-nanomolar 50% inhibitory concentrations (IC50s) against drug-sensitive and multidrug-resistant strains andin vivoefficacy against patent infections ofPlasmodium yoeliiin mice that is superior to chloroquine. Our findings suggest that novel 3-position aryl pharmachin derivatives have the potential for use in treating drug resistant malaria.

scholarly journals In Vitro and In Vivo Studies of Spironolactone as an Antischistosomal Drug Capable of Clinical Repurposing

2018 ◽  
Vol 63 (3) ◽  
Author(s):  
Rafael A. Guerra ◽  
Marcos P. Silva ◽  
Tais C. Silva ◽  
Maria C. Salvadori ◽  
Fernanda S. Teixeira ◽  
...  
Keyword(s):  
Egg Production ◽  
Oral Treatment ◽  
Drug Repurposing ◽  
In Vivo Studies ◽  
Content Type ◽  
Low Concentrations ◽  
Parasitic Flatworm ◽  
And Control

ABSTRACT Schistosomiasis is a parasitic flatworm disease that infects over 200 million people worldwide, especially in poor communities. Treatment and control of the disease rely on just one drug, praziquantel. Since funding for drug development for poverty-associated diseases is very limited, drug repurposing is a promising strategy. In this study, from a screening of 13 marketed diuretics, we identified that spironolactone, a potassium-sparing diuretic, had potent antischistosomal effects on Schistosoma mansoni in vitro and in vivo in a murine model of schistosomiasis. In vitro, spironolactone at low concentrations (<10 µM) is able to alter worm motor activity and the morphology of adult schistosomes, leading to parasitic death. In vivo, oral treatment with spironolactone at a single dose (400 mg/kg) or daily for five consecutive days (100 mg/kg/day) in mice harboring either patent or prepatent infections significantly reduced worm burden, egg production, and hepato- and splenomegaly (P < 0.05 to P < 0.001). Taken together, with the safety profile of spironolactone, supported by its potential to affect schistosomes, these results indicate that spironolactone could be a potential treatment for schistosomiasis and make it promising for repurposing.

scholarly journals Escherichia coli CFT073 Fitness Factors during Urinary Tract Infection: Identification Using an Ordered Transposon Library

2020 ◽  
Vol 86 (13) ◽  
Author(s):  
Allyson E. Shea ◽  
Juan Marzoa ◽  
Stephanie D. Himpsl ◽  
Sara N. Smith ◽  
Lili Zhao ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Human Urine ◽  
Transposon Mutagenesis ◽  
Content Type ◽  
E Coli ◽  
Tract Infections

ABSTRACT Urinary tract infections (UTI), the second most diagnosed infectious disease worldwide, are caused primarily by uropathogenic Escherichia coli (UPEC), placing a significant financial burden on the health care system. High-throughput transposon mutagenesis combined with genome-targeted sequencing is a powerful technique to interrogate genomes for fitness genes. Genome-wide analysis of E. coli requires random libraries of at least 50,000 mutants to achieve 99.99% saturation; however, the traditional murine model of ascending UTI does not permit testing of large mutant pools due to a bottleneck during infection. To address this, an E. coli CFT073 transposon mutant ordered library of 9,216 mutants was created and insertion sites were identified. A single transposon mutant was selected for each gene to assemble a condensed library consisting of 2,913 unique nonessential mutants. Using a modified UTI model in BALB/c mice, we identified 36 genes important for colonizing the bladder, including purB, yihE, and carB. Screening of the condensed library in vitro identified yigP and ubiG to be essential for growth in human urine. Additionally, we developed a novel quantitative PCR (qPCR) technique to identify genes with fitness defects within defined subgroups of related genes (e.g., genes encoding fimbriae, toxins, etc.) following UTI. The number of mutants within these subgroups circumvents bottleneck restriction and facilitates validation of multiple mutants to generate individual competitive indices. Collectively, this study investigates the bottleneck effects during UTI, provides two techniques for evading those effects that can be applied to other disease models, and contributes a genetic tool in prototype strain CFT073 to the field. IMPORTANCE Uropathogenic Escherichia coli strains cause most uncomplicated urinary tract infections (UTI), one of the most common infectious diseases worldwide. Random transposon mutagenesis techniques have been utilized to identify essential bacterial genes during infection; however, this has been met with limitations when applied to the murine UTI model. Conventional high-throughput transposon mutagenesis screens are not feasible because of inoculum size restrictions due to a bottleneck during infection. Our study utilizes a condensed ordered transposon library, limiting the number of mutants while maintaining the largest possible genome coverage. Screening of this library in vivo, and in human urine in vitro, identified numerous candidate fitness factors. Additionally, we have developed a novel technique using qPCR to quantify bacterial outputs following infection with small subgroups of transposon mutants. Molecular approaches developed in this study will serve as useful tools to probe in vivo models that are restricted by anatomical, physiological, or genetic bottleneck limitations.

scholarly journals Activity of LCB01-0371, a Novel Oxazolidinone, against Mycobacterium abscessus

2017 ◽  
Vol 61 (9) ◽  
Author(s):  
Tae Sung Kim ◽  
Jin Ho Choe ◽  
Young Jae Kim ◽  
Chul-Su Yang ◽  
Hyun-Jin Kwon ◽  
...  
Keyword(s):  
Similar Efficacy ◽  
Mycobacterium Abscessus ◽  
Sequencing Analysis ◽  
Highly Pathogenic ◽  
Content Type ◽  
New Class ◽  
Nucleotide Insertion ◽  
Resistant Strains

ABSTRACT Mycobacterium abscessus is a highly pathogenic drug-resistant rapidly growing mycobacterium. In this study, we evaluated the in vitro, intracellular, and in vivo activities of LCB01-0371, a novel and safe oxazolidinone derivative, for the treatment of M. abscessus infection and compared its resistance to that of other oxazolidinone drugs. LCB01-0371 was effective against several M. abscessus strains in vitro and in a macrophage model of infection. In the murine model, a similar efficacy to linezolid was achieved, especially in the lungs. We induced laboratory-generated resistance to LCB01-0371; sequencing analysis revealed mutations in rplC of T424C and G419A and a nucleotide insertion at the 503 position. Furthermore, LCB01-0371 inhibited the growth of amikacin-, cefoxitin-, and clarithromycin-resistant strains. Collectively, our data indicate that LCB01-0371 might represent a promising new class of oxazolidinones with improved safety, which may replace linezolid for the treatment of M. abscessus.

scholarly journals Evaluation of CpxRA as a Therapeutic Target for UropathogenicEscherichia coliInfections

2018 ◽  
Vol 86 (3) ◽  
pp. e00798-17 ◽  
Author(s):  
Lana Dbeibo ◽  
Julia J. van Rensburg ◽  
Sara N. Smith ◽  
Kate R. Fortney ◽  
Dharanesh Gangaiah ◽  
...  
Keyword(s):  
Phosphatase Activity ◽  
Virulence Determinants ◽  
Membrane Repair ◽  
Single Strain ◽  
Content Type ◽  
Phosphatase Inhibitors ◽  
Genes Encoding ◽  
Tract Infections

ABSTRACTCpxRA is an envelope stress response system found in all members of the familyEnterobacteriaceae; CpxA has kinase activity for CpxR and phosphatase activity for phospho-CpxR, a transcription factor. CpxR also accepts phosphate groups from acetyl phosphate, a glucose metabolite. Activation of CpxR increases the transcription of genes encoding membrane repair and downregulates virulence determinants. We hypothesized that activation of CpxR could serve as an antimicrobial/antivirulence strategy and discovered compounds that activate CpxR inEscherichia coliby inhibiting CpxA phosphatase activity. As a prelude to testing such compoundsin vivo, here we constructedcpxA(in the presence of glucose, CpxR is activated because of a lack of CpxA phosphatase) andcpxR(system absent) deletion mutants of uropathogenicE. coli(UPEC) CFT073. By RNA sequencing, few transcriptional differences were noted between thecpxRmutant and its parent, but in thecpxAmutant, several UPEC virulence determinants were downregulated, including thefimandpapoperons, and it exhibited reduced mannose-sensitive hemagglutination of guinea pig red blood cellsin vitro. In competition experiments with mice, both mutants were less fit than the parent in the urine, bladder, and kidney; these fitness defects were complemented intrans. Unexpectedly, in single-strain challenges, only thecpxAmutant was attenuated for virulence in the kidney but not in the bladder or urine. For thecpxAmutant, this may be due to the preferential use of amino acids over glucose as a carbon source in the bladder and urine by UPEC. These studies suggest that CpxA phosphatase inhibitors may have some utility for treating complex urinary tract infections.

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