scholarly journals Detection of Low-Level Fosfomycin-Resistant Variants by Decreasing Glucose-6-Phosphate Concentration in Fosfomycin Susceptibility Determination

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 802
Author(s):  
Guillermo Martín-Gutiérrez ◽  
Fernando Docobo-Pérez ◽  
Jose Manuel Rodríguez-Martínez ◽  
Alvaro Pascual ◽  
Jesús Blázquez ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Coli Strain ◽  
Bacterial Cells ◽  
Resistance Development ◽  
Minimal Inhibitory Concentrations ◽  
E Coli ◽  
Low Level ◽  
Clinical Resistance ◽  
Susceptibility Tests ◽  
Chromosomal Mutations

Mutations that confer low-level fosfomycin resistance (LLFR) but not clinical resistance in Escherichia coli are increasingly reported. LLFR strains can become clinically resistant under urinary tract physiological conditions or may act as gateways for highly resistant subpopulations by the selection of additional LLFR mutations. Nevertheless, most LLFR strains are impossible to detect under routine fosfomycin susceptibility determinations. Here, we have explored the possibility of detecting LLFR variants by reducing glucose-6-phosphate (G6P) concentration in fosfomycin susceptibility testing for E. coli strains. As a proof of concept, fosfomycin minimal inhibitory concentrations (MICs) and disk diffusion susceptibility tests were performed for E. coli strain BW25113 and 10 isogenic derivatives carrying the most prevalent LLFR chromosomal mutations (∆uhpT, ∆glpT, ∆cyaA, and ∆ptsI) and their double combinations. Whereas standard G6P concentrations detected only ∆uhpT single and double variants, assays with reduced G6P detected all LLFR variants. In addition, G6P levels were determined to be ≤5 µg/mL in urine samples from 30 patients with urinary tract infection (UTI) caused by E. coli and 10 healthy volunteers, suggesting that most bacterial cells in uncomplicated UTIs are facing fosfomycin under low G6P concentration. Reducing G6P allows for the detection of LLFR variants, which may suppose a risk for future resistance development, especially in UTIs.

scholarly journals Evaluation of Immunocompetent Urinary Tract Infected Balb/C Mouse Model For the Study of Antibiotic Resistance Development Using Escherichia Coli CFT073 Infection

Antibiotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 170 ◽  
Author(s):  
Ashok Chockalingam ◽  
Sharron Stewart ◽  
Lin Xu ◽  
Adarsh Gandhi ◽  
Murali K. Matta ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Urinary Tract ◽  
Bladder Tissue ◽  
Resistance Development ◽  
Once Daily ◽  
E Coli ◽  
Low Levels ◽  
Tract Infections

Urinary tract infections (UTI) are common worldwide and are becoming increasingly difficult to treat because of the development of antibiotic resistance. Immunocompetent murine models of human UTI have been used to study pathogenesis and treatment but not for investigating resistance development after treatment with antibiotics. In this study, intravesical inoculation of uropathogenic Escherichia coli CFT073 in immunocompetent Balb/c mice was used as a model of human UTI. The value of the model in investigating antibiotic exposure on in vivo emergence of antibiotic resistance was examined. Experimentally infected mice were treated with 20 or 200 mg/kg ampicillin, 5 or 50 mg/kg ciprofloxacin, or 100 or 1000 mg/kg of fosfomycin. Ampicillin and ciprofloxacin were given twice daily at 8 h intervals, and fosfomycin was given once daily. Antibiotic treatment began 24 h after bacterial inoculation and ended after 72 h following the initial treatment. Although minimum inhibitory concentrations (MIC) for the experimental strain of E. coli were exceeded at peak concentrations in tissues and consistently in urine, low levels of bacteria persisted in tissues in all experiments. E. coli from bladder tissue, kidney, and urine grew on plates containing 1× MIC of antibiotic, but none grew at 3× MIC. This model is not suitable for studying emergent resistance but might serve to examine bacterial persistence.

scholarly journals Towards Bacteria Counting in DI Water of Several Microliters or Growing Suspension Using Impedance Biochips

Biosensors ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 82
Author(s):  
Mahdi Kiani ◽  
Astrid Tannert ◽  
Nan Du ◽  
Uwe Hübner ◽  
Ilona Skorupa ◽  
...  
Keyword(s):  
Optical Density ◽  
Coli Strain ◽  
Bacterial Cells ◽  
Impedance Measurements ◽  
E Coli ◽  
Impedance Data ◽  
Impedance Parameters

We counted bacterial cells of E. coli strain K12 in several-microliter DI water or in several-microliter PBS in the low optical density (OD) range (OD = 0.05–1.08) in contact with the surface of Si-based impedance biochips with ring electrodes by impedance measurements. The multiparameter fit of the impedance data allowed calibration of the impedance data with the concentration cb of the E. coli cells in the range of cb = 0.06 to 1.26 × 109 cells/mL. The results showed that for E. coli in DI water and in PBS, the modelled impedance parameters depend linearly on the concentration of cells in the range of cb = 0.06 to 1.26 × 109 cells/mL, whereas the OD, which was independently measured with a spectrophotometer, was only linearly dependent on the concentration of the E. coli cells in the range of cb = 0.06 to 0.50 × 109 cells/mL.

scholarly journals Asymptomatic bacteriuria Escherichia coli strain 83972 carries mutations in the foc locus and is unable to express F1C fimbriae

Microbiology ◽  
2006 ◽  
Vol 152 (6) ◽  
pp. 1799-1806 ◽  
Author(s):  
Viktoria Roos ◽  
Mark A. Schembri ◽  
Glen C. Ulett ◽  
Per Klemm
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Gene Cluster ◽  
Asymptomatic Bacteriuria ◽  
Human Kidney ◽  
Coli Strain ◽  
Gene Encoding ◽  
Symptomatic Urinary Tract Infection ◽  
E Coli ◽  
Colonization Factor

Escherichia coli is the most common organism associated with asymptomatic bacteriuria (ABU). In contrast to uropathogenic E. coli (UPEC), which causes symptomatic urinary tract infection (UTI), very little is known about the mechanisms by which these strains colonize the urinary tract. Bacterial adhesion conferred by specific surface-associated adhesins is normally considered as a prerequisite for colonization of the urinary tract. The prototype ABU E. coli strain 83972 was originally isolated from a girl who had carried it asymptomatically for 3 years. This study characterized the molecular status of one of the primary adhesion factors known to be associated with UTI, namely F1C fimbriae, encoded by the foc gene cluster. F1C fimbriae recognize receptors present in the human kidney and bladder. Expression of the foc genes was found to be up-regulated in human urine. It was also shown that although strain 83972 contains a seemingly intact foc gene cluster, F1C fimbriae are not expressed. Sequencing and genetic complementation revealed that the focD gene, encoding a component of the F1C transport and assembly system, was non-functional, explaining the inability of strain 83972 to express this adhesin. The data imply that E. coli 83972 has lost its ability to express this important colonization factor as a result of host-driven evolution. The ancestor of the strain seems to have been a pyelonephritis strain of phylogenetic group B2. Strain 83972 therefore represents an example of bacterial adaptation from pathogenicity to commensalism through virulence factor loss.

scholarly journals Low-Level Organic Solvents Improve Multienzyme Whole-Cell Catalytic Synthesis of Myricetin-7-O-Glucuronide

Catalysts ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 970 ◽  
Author(s):  
Yan Yang ◽  
Min-Zhi Liu ◽  
Yun-Song Cao ◽  
Chang-Kun Li ◽  
Wei Wang
Keyword(s):  
Cell Membrane ◽  
Organic Solvents ◽  
Membrane Integrity ◽  
Industrial Applications ◽  
Coli Strain ◽  
Whole Cell ◽  
Cell Membrane Integrity ◽  
E Coli ◽  
Low Level ◽  
Whole Cell Catalysis

Multienzyme whole-cell biocatalysts are preferred in industrial applications, and two major concerns regarding the use of these biocatalysts, cell viability and cell membrane integrity, must be addressed. In this work, the transformation of myricetin to myricetin-7-O-glucuronide catalyzed by an engineered Escherichia coli strain was taken as the model reaction to examine the impacts of low-level organic solvents on whole-cell biocatalysis. Low-level organic solvents (2%, v/v) showed a significant increase (roughly 13-fold) in myricetin-7-O-glucuronide yields. No obvious compromises of cellular viability and integrity were observed by a flow cytometry assay or in the determination of extracellular protein leakage, suggesting the addition of low-level organic solvents accommodates whole E. coli cells. Furthermore, a scaled-up reaction was conducted to test the capability and efficiency of whole-cell catalysis in the presence of organic solvents. This study presents a promising and simple means to enhance the productivity of multienzyme whole-cell catalysis without losing the barrier functions of the cell membrane.

scholarly journals Urinary Tract Conditions Affect Fosfomycin Activity against Escherichia coli Strains Harboring Chromosomal Mutations Involved in Fosfomycin Uptake

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
G. Martín-Gutiérrez ◽  
F. Docobo-Pérez ◽  
J. Rodriguez-Beltrán ◽  
J. M. Rodríguez-Martínez ◽  
J. Aznar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Practical Interest ◽  
Resistance Mutations ◽  
Urine Ph ◽  
Content Type ◽  
E Coli ◽  
Ph Values ◽  
Tract Infections ◽  
Chromosomal Mutations

ABSTRACTThe steps by whichEscherichia colistrains harboring mutations related to fosfomycin (FOS) resistance arise and spread during urinary tract infections (UTIs) are far from being understood. The aim of this study was to evaluate the effects of urine, pH, and anaerobiosis on FOS activity against a set of isogenic strains carrying the most prevalent chromosomal mutations conferring FOS resistance (ΔuhpT, ΔglpT, ΔcyaA, and ΔptsI), either singly or in combination. We also studied fosfomycin-resistantE. coliclinical isolates from patients with UTI. Our results demonstrate that urinary tract physiological conditions might have a profound impact on FOS activity against strains with chromosomal FOS resistance mutations. Specifically, acidic pH values and anaerobiosis convert most of the strains categorized as resistant to fosfomycin according to the international guidelines to a susceptible status. Therefore, urinary pH values may have practical interest in the management of UTIs. Finally, our results, together with the high fitness cost associated with FOS resistance mutations, might explain the low prevalence of fosfomycin-resistantE. colivariants in UTIs.

scholarly journals Ciprofloxacin Pharmacokinetics/Pharmacodynamics against Susceptible and Low-Level Resistant Escherichia coli Isolates in an Experimental Ascending Urinary Tract Infection Model in Mice

2020 ◽  
Vol 65 (1) ◽  
pp. e01804-20
Author(s):  
Lotte Jakobsen ◽  
Carina Vingsbro Lundberg ◽  
Niels Frimodt-Møller
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
Infection Model ◽  
Bladder Tissue ◽  
Content Type ◽  
E Coli ◽  
Low Level ◽  
Level Resistance

ABSTRACTThe mouse ascending urinary tract infection model was used to study the pharmacokinetic/pharmacodynamic (PKPD) relationships of the effect of ciprofloxacin in subcutaneous treatment for 3 days with varying doses and dosing intervals against a susceptible Escherichia coli strain (MIC, 0.032 mg/liter). Further, a humanized dose of ciprofloxacin was administered for 3 days against three E. coli strains with low-level resistance, i.e., MICs of 0.06, 0.25, and 1 mg/liter, respectively. Against the susceptible isolate, ciprofloxacin was highly effective in clearing the urine with daily doses from 10 mg/kg, but the dosing regimen had to be divided into at least two doses for optimal effect. Ciprofloxacin could not clear the urine or kidneys for the low-level-resistant strains. PKPD correlations with all strains combined showed that for the AUC24/MIC there was a slightly higher correlation with effect in urine and kidneys (R2, 0.71 and 0.69, respectively) than the %T>MIC (R2, 0.41 and 0.61, respectively). Equal correlations for the two PKPD indices were found for reduction of colony counts (CFU) in the bladder tissue, but not even the highest dose of 28 mg/kg × 6 could clear the bladder tissue. In conclusion, ciprofloxacin is highly effective in clearing the urine and kidney tissue for fully susceptible E. coli, while even low-level resistance in E. coli obscures this effect. While the effect of ciprofloxacin is mostly AUC/MIC driven against E. coli infection in the urinary tract, the effect in urine depends on the presence of ciprofloxacin in the urine during most of a 24-h period.

scholarly journals Mutant RNA polymerase can reduce susceptibility to antibiotics via ppGpp-independent induction of a stringent-like response

2020 ◽  
Author(s):  
Gerrit Brandis ◽  
Susanna Granström ◽  
Anna T Leber ◽  
Katrin Bartke ◽  
Linnéa Garoff ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Drug Susceptibility ◽  
Relative Fitness ◽  
Resistance Development ◽  
E Coli ◽  
Activating Mutations ◽  
Transcriptional Reprogramming ◽  
Clinical Resistance ◽  
Compensatory Mutations ◽  
Selection For

Abstract Background Mutations in RNA polymerase (RNAP) can reduce susceptibility to ciprofloxacin in Escherichia coli, but the mechanism of transcriptional reprogramming responsible is unknown. Strains carrying ciprofloxacin-resistant (CipR) rpoB mutations have reduced growth fitness and their impact on clinical resistance development is unclear. Objectives To assess the potential for CipRrpoB mutations to contribute to resistance development by estimating the number of distinct alleles. To identify fitness-compensatory mutations that ameliorate the fitness costs of CipRrpoB mutations. To understand how CipRrpoB mutations reprogramme RNAP. Methods E. coli strains carrying five different CipRrpoB alleles were evolved with selection for improved fitness and characterized for acquired mutations, relative fitness and MICCip. The effects of dksA mutations and a ppGpp0 background on growth and susceptibility phenotypes associated with CipRrpoB alleles were determined. Results The number of distinct CipRrpoB mutations was estimated to be >100. Mutations in RNAP genes and in dksA can compensate for the fitness cost of CipRrpoB mutations. Deletion of dksA reduced the MICCip for strains carrying CipRrpoB alleles. A ppGpp0 phenotype had no effect on drug susceptibility. Conclusions CipRrpoB mutations induce an ppGpp-independent stringent-like response. Approximately half of the reduction in ciprofloxacin susceptibility is caused by an increased affinity of RNAP to DksA while the other half is independent of DksA. Stringent-like response activating mutations might be the most diverse class of mutations reducing susceptibility to antibiotics.

scholarly journals Antimicrobial Resistance in Escherichia coli and Resistance Genes in Coliphages from a Small Animal Clinic and in a Patient Dog with Chronic Urinary Tract Infection

Antibiotics ◽  
2020 ◽  
Vol 9 (10) ◽  
pp. 652
Author(s):  
Veronika Zechner ◽  
Dmitrij Sofka ◽  
Peter Paulsen ◽  
Friederike Hilbert
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Antimicrobial Resistance ◽  
Tract Infection ◽  
Resistance Genes ◽  
Small Animal ◽  
Laboratory Strain ◽  
Coli Strain ◽  
E Coli ◽  
Chronic Urinary Tract Infection

Antimicrobial resistance is on the rise in certain pathogens that infect pets and their owners. This has raised concerns about the use of antibiotics and the transfer of resistance elements in small animal clinics. We sampled a surgery unit, diagnostic rooms after disinfection, and a dog with chronic urinary tract infection (UTI), in a small animal clinic in Austria, and isolated/characterized phages and Escherichia (E.) coli for antimicrobial resistance, resistance genes and transduction ability. Neither the coliphages nor E. coli were isolated in the 20 samples of the surgery units and diagnostic rooms. From the urinary tract of the dog, we recovered 57 E. coli isolates and 60 coliphages. All of the E. coli isolates were determined as resistant against nalidixic acid, 47 against ampicillin, 34 against sulfonamides, and 33 against streptomycin. No isolate held resistance against tetracycline, trimethoprim, kanamycin, or chloramphenicol. Among the 60 phages, 29 tested positive for one or more resistance gene(s) by PCR, but none was able to transduce it to a laboratory strain or to an E. coli isolated from samples. Nevertheless, six phages out of 60 were able to transduce ampicillin resistance (bla gene) after being grown on a puc19 harboring E. coli strain.

scholarly journals Identity of blaCTX-M Carrying Plasmids in Sequential ESBL-E. coli Isolates from Patients with Recurrent Urinary Tract Infections

2021 ◽  
Vol 9 (6) ◽  
pp. 1138
Author(s):  
Nahid Karami ◽  
Sriram KK ◽  
Shora Yazdanshenas ◽  
Yii-Lih Lin ◽  
Daniel Jaén-Luchoro ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Rare Event ◽  
Coli Strain ◽  
Health It ◽  
Extended Spectrum Beta Lactamase ◽  
E Coli ◽  
Recurrent Urinary Tract Infections ◽  
Global Threat ◽  
Tract Infections

Plasmid-mediated multidrug resistance in E. coli is becoming increasingly prevalent. Considering this global threat to human health, it is important to understand how plasmid-mediated resistance spreads. From a cohort of 123 patients with recurrent urinary tract infections (RUTI) due to extended spectrum beta-lactamase (ESBL)-producing Escherichia coli (ESBL E. coli), only five events with a change of ESBL E. coli strain between RUTI episodes were identified. Their blaCTX-M encoding plasmids were compared within each pair of isolates using optical DNA mapping (ODM) and PCR-based replicon typing. Despite similar blaCTX-M genes and replicon types, ODM detected only one case with identical plasmids in the sequential ESBL E. coli strains, indicating that plasmid transfer could have occurred. For comparison, plasmids from seven patients with the same ESBL E. coli strain reoccurring in both episodes were analyzed. These plasmids (encoding blaCTX-M-3, blaCTX-M-14, and blaCTX-M-15) were unaltered for up to six months between recurrent infections. Thus, transmission of blaCTX-M plasmids appears to be a rare event during the course of RUTI. Despite the limited number (n = 23) of plasmids investigated, similar blaCTX-M-15 plasmids in unrelated isolates from different patients were detected, suggesting that some successful plasmids could be associated with specific strains, or are more easily transmitted.

scholarly journals Bilateral pyelonephritis due to Escherichia coli infection in a captive jaguar (Panthera onca)

2020 ◽  
Vol 40 (7) ◽  
pp. 554-558
Author(s):  
Julia G. Wronski ◽  
Fernando F. Argenta ◽  
Jacqueline Raiter ◽  
Luiza P. Ehlers ◽  
Rafaella D.V. Sala ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
First Generation ◽  
Generation Cephalosporin ◽  
Coli Strain ◽  
Panthera Onca ◽  
E Coli ◽  
Morphologic Characteristics ◽  
Escherichia Coli Infection ◽  
Systemic Infections

ABSTRACT: Extraintestinal pathogenic Escherichia coli (ExPEC) is a highly diverse pathotype of E. coli which colonizes the intestine, and it is considered an important etiological agent associated with bacteremia and other systemic infections, among them urinary tract infection. Retrospective studies evaluating morbidity and mortality of nondomestic felids have demonstrated that urinary tract diseases are among the main causes of death for geriatric animals. Also, mesenchymal neoplasms of the uterus are common in wild felids, and they possess variable morphologic characteristics related to invasiveness and malignancy. This report describes a case of bilateral pyelonephritis due to extraintestinal uropathogenic E. coli infection in a captive jaguar (Panthera onca). The diagnosis was confirmed through pathological, bacterial and immunohistochemical findings. According to molecular analysis, this E. coli strain was classified in the phylogroup F, possessing the following virulence-associated genes: usp, cnf-1, hlyA, papC and sfa. Additionally, this E. coli was highly resistant to β-lactams and first-generation cephalosporin. This jaguar also presented a uterine leiomyoma with distinct distribution, and severe degenerative articular disease, both of them described as frequently seen lesions in geriatric animals from the Panthera genus.

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