scholarly journals Oral Fosfomycin Treatment for Enterococcal Urinary Tract Infections in a Dynamic In Vitro Model

2020 ◽  
Vol 64 (6) ◽  
Author(s):  
Iain J. Abbott ◽  
Elke van Gorp ◽  
Aart van der Meijden ◽  
Rixt A. Wijma ◽  
Joseph Meletiadis ◽  
...  
Keyword(s):  
Single Dose ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Treatment Options ◽  
Infection Model ◽  
Urinary Concentration ◽  
Content Type ◽  
Vitro Model ◽  
Tract Infections

ABSTRACT There are limited treatment options for enterococcal urinary tract infections, especially vancomycin-resistant Enterococcus (VRE). Oral fosfomycin is a potential option, although limited data are available guiding dosing and susceptibility. We undertook pharmacodynamic profiling of fosfomycin against E. faecalis and E. faecium isolates using a dynamic in vitro bladder infection model. Eighty-four isolates underwent fosfomycin agar dilution susceptibility testing (E. faecalis MIC50/90 32/64 μg/ml; E. faecium MIC50/90 64/128 μg/ml). Sixteen isolates (including E. faecalis ATCC 29212 and E. faecium ATCC 35667) were chosen to reflect the MIC range and tested in the bladder infection model with synthetic human urine (SHU). Under drug-free conditions, E. faecium demonstrated greater growth restriction in SHU compared to E. faecalis (E. faecium maximal growth 5.8 ± 0.6 log10 CFU/ml; E. faecalis 8.0 ± 1.0 log10 CFU/ml). Isolates were exposed to high and low fosfomycin urinary concentrations after a single dose, and after two doses given over two days with low urinary concentration exposure. Simulated concentrations closely matched the target (bias 2.3%). E. faecalis isolates required greater fosfomycin exposure for 3 log10 kill from the starting inoculum compared with E. faecium. The ƒAUC0-72/MIC and ƒ%T > MIC0-72 for E. faecalis were 672 and 70%, compared to 216 and 51% for E. faecium, respectively. There was no rise in fosfomycin MIC postexposure. Two doses of fosfomycin with low urinary concentrations resulted in equivalent growth inhibition to a single dose with high urinary concentrations. With this urinary exposure, fosfomycin was effective in promoting suppression of regrowth (>3 log10 kill) in the majority of isolates.

Efficacy of single and multiple oral doses of fosfomycin against Pseudomonas aeruginosa urinary tract infections in a dynamic in vitro bladder infection model

2020 ◽  
Vol 75 (7) ◽  
pp. 1879-1888 ◽  
Author(s):  
Iain J Abbott ◽  
Elke van Gorp ◽  
Rixt A Wijma ◽  
Jordy Dekker ◽  
Peter D Croughs ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Single Dose ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Infection Model ◽  
Post Exposure ◽  
High Level ◽  
Tract Infections ◽  
Emergence Of Resistance

Abstract Objectives We used a dynamic bladder infection in vitro model with synthetic human urine (SHU) to examine fosfomycin exposures to effectively kill, or prevent emergence of resistance, among Pseudomonas aeruginosa isolates. Methods Dynamic urinary fosfomycin concentrations after 3 g oral fosfomycin were simulated, comparing single and multiple (daily for 7 days) doses. Pharmacodynamic response of 16 P. aeruginosa (MIC range 1 to >1024 mg/L) were examined. Baseline disc diffusion susceptibility, broth microdilution MIC and detection of heteroresistance were assessed. Pathogen kill and emergence of resistance over 72 h following a single dose, and over 216 h following daily dosing for 7 days, were investigated. The fAUC0–24/MIC associated with stasis and 1, 2 and 3 log10 kill were determined. Results Pre-exposure high-level resistant (HLR) subpopulations were detected in 11/16 isolates after drug-free incubation in the bladder infection model. Five of 16 isolates had >2 log10 kill after single dose, reducing to 2/16 after seven doses. Post-exposure HLR amplification occurred in 8/16 isolates following a single dose and in 11/16 isolates after seven doses. Baseline MIC ≥8 mg/L with an HLR subpopulation predicted post-exposure emergence of resistance following the multiple doses. A PK/PD target of fAUC0–24/MIC >5000 was associated with 3 log10 kill at 72 h and 7 day-stasis. Conclusions Simulated treatment of P. aeruginosa urinary tract infections with oral fosfomycin was ineffective, despite exposure to high urinary concentrations and repeated daily doses for 7 days. Emergence of resistance was observed in the majority of isolates and worsened following prolonged therapy. Detection of a baseline resistant subpopulation predicted treatment failure.

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 An in vitro model of catheter-associated urinary tract infections to investigate the role of uncommon bacteria on the Escherichia coli microbial consortium

2017 ◽  
Vol 118 ◽  
pp. 64-69 ◽  
Author(s):  
Andreia S. Azevedo ◽  
Carina Almeida ◽  
Luciana C. Gomes ◽  
Carla Ferreira ◽  
Filipe J. Mergulhão ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
In Vitro Model ◽  
Microbial Consortium ◽  
Vitro Model ◽  
Tract Infections

scholarly journals Experience with Fosfomycin for Treatment of Urinary Tract Infections Due to Multidrug-Resistant Organisms

2012 ◽  
Vol 56 (11) ◽  
pp. 5744-5748 ◽  
Author(s):  
Elizabeth A. Neuner ◽  
Jennifer Sekeres ◽  
Gerri S. Hall ◽  
David van Duin
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Multidrug Resistant ◽  
Solid Organ ◽  
Content Type ◽  
Failure Group ◽  
Tract Infections ◽  
Microbiological Cure ◽  
Esbl Producers

ABSTRACTFosfomycin has shown promisingin vitroactivity against multidrug-resistant (MDR) urinary pathogens; however, clinical data are lacking. We conducted a retrospective chart review to describe the microbiological and clinical outcomes of urinary tract infections (UTIs) with MDR pathogens treated with fosfomycin tromethamine. Charts for 41 hospitalized patients with a urine culture for an MDR pathogen who received fosfomycin tromethamine from 2006 to 2010 were reviewed. Forty-one patients had 44 urinary pathogens, including 13 carbapenem-resistantKlebsiella pneumoniae(CR-Kp), 8Pseudomonas aeruginosa, and 7 vancomycin-resistantEnterococcus faecium(VRE) isolates, 7 extended-spectrum beta-lactamase (ESBL) producers, and 9 others.In vitrofosfomycin susceptibility was 86% (median MIC, 16 μg/ml; range, 0.25 to 1,024 μg/ml). Patients received an average of 2.9 fosfomycin doses per treatment course. The overall microbiological cure was 59%; failure was due to either relapse (24%) or reinfection UTI (17%). Microbiological cure rates by pathogen were 46% for CR-Kp, 38% forP. aeruginosa, 71% for VRE, 57% for ESBL producers, and 100% for others. Microbiological cure (n= 24) was compared to microbiological failure (n= 17). There were significantly more solid organ transplant recipients in the microbiological failure group (59% versus 21%;P= 0.02). None of the patients in the microbiological cure group had a ureteral stent, compared to 24% of patients within the microbiological failure group (P= 0.02). Fosfomycin demonstratedin vitroactivity against UTIs due to MDR pathogens. For CR-KP, there was a divergence betweenin vitrosusceptibility (92%) and microbiological cure (46%). Multiple confounding factors may have contributed to microbiological failures, and further data regarding the use of fosfomycin for UTIs due to MDR pathogens are needed.

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 In VivoPharmacodynamic Profile of Ceftibuten-Clavulanate Combination against Extended-Spectrum-β-Lactamase-ProducingEnterobacteriaceaein the Murine Thigh Infection Model

2019 ◽  
Vol 63 (7) ◽  
Author(s):  
Kamilia Abdelraouf ◽  
Sean M. Stainton ◽  
David P. Nicolau
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Plasma Concentrations ◽  
Threshold Concentration ◽  
Dose Fractionation ◽  
Infection Model ◽  
Content Type ◽  
Extended Spectrum ◽  
Dose Ranging ◽  
Tract Infections

ABSTRACTCeftibuten-clavulanate (CTB-CLA) is a novel β-lactam–β-lactamase combination with potential utility for the management of urinary tract infections caused by extended-spectrum-β-lactamase (ESBL)-producing organisms. We examined the pharmacodynamics of the combination against 25Enterobacteriaceaeexpressing β-lactamases (CTX-M, TEM, and SHV wild types and SHV-ESBL) in the murine thigh infection model. MIC values of CTB and CTB-CLA ranged from 1 to >32 mg/liter and 0.125 to 8 mg/liter, respectively. Human-simulated regimens of CTB and CLA equivalent to clinical doses of 400 mg orally (p.o.) every 8 h (q8h) and 187 mg q8h, respectively, were developed. CLA dose fractionation studies were undertaken to characterize the driver of efficacy. CLA dose-ranging studies were undertaken to assess the activity of the CTB human-simulated regimen in combination with escalating CLA exposures. The relationships between the percentage of the dosing interval during which the free CLA plasma concentrations remained above a threshold concentration (%fT>CT) and the change in log10CFU per thigh at 24 h were examined across different threshold concentrations. Additionally, the efficacy of a human-simulated regimen of CTB-CLA was assessed against isolates with various susceptibilities to the combination. The pharmacokinetic/pharmacodynamic index that best correlated with the efficacy of the combination was %fT> threshold CLA plasma concentration of 0.5 mg/liter. The plasma %fT>0.5 mg/liter associated with the static endpoint was 20.59%. For isolates with CTB-CLA MICs of ≤4 mg/liter, stasis was achieved with a human-simulated regimen of CTB-CLA against 20/22 isolates (90.9%), while for isolates with MICs of 8 mg/liter, only 1/3 tested isolates (33.3%) displayed stasis. Results suggest a susceptibility breakpoint of 4 mg/liter for CTB-CLA. These data support the consideration of the CTB-CLA combination for the treatment of urinary tract infections due to ESBL-producingEnterobacteriaceae.

scholarly journals Role of Klebsiella pneumoniae Type 1 and Type 3 Fimbriae in Colonizing Silicone Tubes Implanted into the Bladders of Mice as a Model of Catheter-Associated Urinary Tract Infections

2013 ◽  
Vol 81 (8) ◽  
pp. 3009-3017 ◽  
Author(s):  
Caitlin N. Murphy ◽  
Martin S. Mortensen ◽  
Karen A. Krogfelt ◽  
Steven Clegg
Keyword(s):  
Urinary Tract ◽  
Klebsiella Pneumoniae ◽  
Urinary Tract Infections ◽  
Wild Type ◽  
Content Type ◽  
Tract Infections ◽  
Type 3

ABSTRACTCatheter-associated urinary tract infections are biofilm-mediated infections that cause a significant economic and health burden in nosocomial environments. Using a newly developed murine model of this type of infection, we investigated the role of fimbriae in implant-associated urinary tract infections by the Gram-negative bacteriumKlebsiella pneumoniae, which is a proficient biofilm former and a commonly isolated nosocomial pathogen. Studies have shown that type 1 and type 3 fimbriae are involved in attachment and biofilm formationin vitro, and these fimbrial types are suspected to be important virulence factors during infection. To test this hypothesis, the virulence of fimbrial mutants was assessed in independent challenges in which mouse bladders were inoculated with the wild type or a fimbrial mutant and in coinfection studies in which the wild type and fimbrial mutants were inoculated together to assess the results of a direct competition in the urinary tract. Using these experiments, we were able to show that both fimbrial types serve to enhance colonization and persistence. Additionally, a double mutant had an additive colonization defect under some conditions, indicating that both fimbrial types have unique roles in the attachment and persistence in the bladder and on the implant itself. All of these mutants were outcompeted by the wild type in coinfection experiments. Using these methods, we are able to show that type 1 and type 3 fimbriae are important colonization factors in the murine urinary tract when an implanted silicone tube is present.

scholarly journals Urinary Tract Infections among Indonesian Pregnant Women and Its Susceptibility Pattern

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Yeva Rosana ◽  
Dwiana Ocviyanti ◽  
Melissa Halim ◽  
Friza Yossy Harlinda ◽  
Rahmah Amran ◽  
...  
Keyword(s):  
Single Dose ◽  
Urinary Tract ◽  
Pregnant Women ◽  
Urinary Tract Infections ◽  
Asymptomatic Bacteriuria ◽  
In Vitro Susceptibility ◽  
E Coli ◽  
Fosfomycin Trometamol ◽  
Tract Infections

Pregnant women are usually at risk of urinary tract infections (UTIs) such as asymptomatic bacteriuria. In the current multidrug-resistance era, appropriate diagnosis and treatment should be provided to avoid complications in pregnant women in developing countries, which have limited facilities, such as Indonesia. The aim of this study was to evaluate in vitro susceptibility tests. Urinary isolates were collected from 715 pregnant women who visited eight Community Health Centers in Jakarta, Indonesia, between 2015 and 2017. We identified bacterial uropathogens from samples that were positive for nitrite/leukocyte esterase (LE), using two types of VITEK cards. Since noncompliance among patients is a major problem, fosfomycin-trometamol 3 g single-dose sachets were given to the patients, and the side effects of the medication and neonatal outcomes were reported. Asymptomatic bacteriuria was found in 10.5% of the 715 pregnant women. Escherichia coli was the most common etiological factor (26.7%), followed by Klebsiella pneumoniae (20%), Streptococcus agalactiae (9.3%), Enterobacter cloacae (5.3%), Enterococcus faecalis (5.3%), Staphylococcus saprophyticus (4%), Acinetobacter baumannii (4%), and others. Out of 76 pregnant women who took fosfomycin-trometamol, two complained of diarrhea that subsided without medication and fever that responded to paracetamol. Neonatal outcomes showed 100% full-term and normal-weight babies. E. coli, including extended-spectrum beta-lactamase- (ESBL-) producing E. coli, was 100% susceptible to fosfomycin. Nitrite/LE test results are often used as evidence for empiric antibiotic administration for treating asymptomatic bacteriuria in pregnancy, but the diagnosis should be confirmed using culture tests. Based on in vitro susceptibility patterns and medication outcomes, fosfomycin-trometamol single dose could be administered to noncompliant UTI patients, including pregnant women.

scholarly journals Foley Catheter with Peri-Urethral Antimicrobial Irrigation for the Prevention of Catheter Associated Urinary Tract Infections – Assessment in an In Vitro Model

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S481-S481 ◽  
Author(s):  
Joel Rosenblatt ◽  
Ruth Reitzel ◽  
Nylev Vargas-Cruz ◽  
Anne-Marie Chaftari ◽  
Ray Y Hachem ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
In Vitro Model ◽  
Foley Catheter ◽  
Vitro Model ◽  
Tract Infections
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