Impact of bacterial species and baseline resistance on fosfomycin efficacy in urinary tract infections

2019 ◽  
Vol 75 (4) ◽  
pp. 988-996 ◽  
Author(s):  
Iain J Abbott ◽  
Jordy Dekker ◽  
Elke van Gorp ◽  
Rixt A Wijma ◽  
Merel N Raaphorst ◽  
...  
Keyword(s):  
In Vitro Model ◽  
Bacterial Species ◽  
Clinical Isolates ◽  
Infection Model ◽  
Limit Of Quantification ◽  
E Coli ◽  
Mutant Prevention Concentration ◽  
Vitro Model ◽  
Tract Infections

Abstract Objectives To assess the antibacterial effects of a single 3 g oral fosfomycin dose on Escherichia coli and Klebsiella pneumoniae clinical isolates within a dynamic bladder infection model. Methods An in vitro model simulating dynamic urinary fosfomycin concentrations was used. Target fosfomycin exposure (Cmax = 1984 mg/L and Tmax = 7.5 h) was validated by LC-MS/MS. Pharmacodynamic responses of 24 E. coli and 20 K. pneumoniae clinical isolates were examined (fosfomycin MIC ≤0.25–128 mg/L). Mutant prevention concentration (MPC), fosfomycin heteroresistance, fosfomycin resistance genes and fosA expression were examined. Pathogen kill and emergence of high-level resistance (HLR; MIC >1024 mg/L) were quantified. Results Following fosfomycin exposure, 20 of 24 E. coli exhibited reductions in bacterial counts below the lower limit of quantification without regrowth, despite baseline fosfomycin MICs up to 128 mg/L. Four E. coli regrew (MIC = 4–32 mg/L) with HLR population replacement. At baseline, these isolates had detectable HLR subpopulations and MPC >1024 mg/L. All E. coli isolates were fosA negative. In contrast, 17 of 20 K. pneumoniae regrew post exposure, 6 with emergence of HLR (proportion = 0.01%–100%). The three isolates without regrowth did not have a detectable HLR subpopulation after dynamic drug-free incubation. All K. pneumoniae had MPC >1024 mg/L and were fosA positive. WGS analysis and fosA expression failed to predict fosfomycin efficacy. Conclusions E. coli and K. pneumoniae isolates demonstrate discrepant responses to a single fosfomycin dose in a dynamic bladder infection in vitro model. Treatment failure against E. coli was related to an HLR subpopulation, not identified by standard MIC testing. Activity against K. pneumoniae appeared limited, regardless of MIC testing, due to universal baseline heteroresistance.

scholarly journals Biological Cost of Single and Multiple Norfloxacin Resistance Mutations in Escherichia coli Implicated in Urinary Tract Infections

2005 ◽  
Vol 49 (6) ◽  
pp. 2343-2351 ◽  
Author(s):  
Patricia Komp Lindgren ◽  
Linda L. Marcusson ◽  
Dorthe Sandvang ◽  
Niels Frimodt-Møller ◽  
Diarmaid Hughes
Keyword(s):  
Escherichia Coli ◽  
Urinary Tract ◽  
Infection Model ◽  
Resistance Mutations ◽  
Topoisomerase Iv ◽  
E Coli ◽  
Tract Infections ◽  
Subsequent Selection

ABSTRACT Resistance to fluoroquinolones in urinary tract infection (UTIs) caused by Escherichia coli is associated with multiple mutations, typically those that alter DNA gyrase and DNA topoisomerase IV and those that regulate AcrAB-TolC-mediated efflux. We asked whether a fitness cost is associated with the accumulation of these multiple mutations. Mutants of the susceptible E. coli UTI isolate Nu14 were selected through three to five successive steps with norfloxacin. Each selection was performed with the MIC of the selected strain. After each selection the MIC was measured; and the regions of gyrA, gyrB, parC, and parE, previously associated with resistance mutations, and all of marOR and acrR were sequenced. The first selection step yielded mutations in gyrA, gyrB, and marOR. Subsequent selection steps yielded mutations in gyrA, parE, and marOR but not in gyrB, parC, or acrR. Resistance-associated mutations were identified in almost all isolates after selection steps 1 and 2 but in less than 50% of isolates after subsequent selection steps. Selected strains were competed in vitro, in urine, and in a mouse UTI infection model against the starting strain, Nu14. First-step mutations were not associated with significant fitness costs. However, the accumulation of three or more resistance-associated mutations was usually associated with a large reduction in biological fitness, both in vitro and in vivo. Interestingly, in some lineages a partial restoration of fitness was associated with the accumulation of additional mutations in late selection steps. We suggest that the relative biological costs of multiple mutations may influence the evolution of E. coli strains that develop resistance to fluoroquinolones.

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

Leukocyte antibacterial functions are not impaired by perfluorocarbon exposure in vitro

2008 ◽  
Vol 295 (1) ◽  
pp. L134-L142 ◽  
Author(s):  
Dirk Haufe ◽  
Eva Koenigshausen ◽  
Lilla Knels ◽  
Martina Wendel ◽  
Sebastian N. Stehr ◽  
...  
Keyword(s):  
Host Defense ◽  
In Vitro Model ◽  
Polymorphonuclear Neutrophils ◽  
Human Neutrophils ◽  
Intracellular Uptake ◽  
E Coli ◽  
Transmission Electron ◽  
Membrane Bound ◽  
Vitro Model

Application of liquid, aerosolized, and vaporized perfluorocarbons (PFC) in acute lung injury has shown anti-inflammatory effects. Although this may be beneficial in states of pulmonary hyperinflammation, it also could increase susceptibility to nosocomial lung infection. We hypothesized that PFC impair cellular host defense and therefore investigated in an in vitro model the influence of perfluorohexane (PFH) on crucial mechanisms of bacterial elimination in human neutrophils and monocytes. Using scanning and transmission electron microscopy, we could show membrane-bound and ingested PFH particles that morphologically did not alter adherence and phagocytosis of Escherichia coli or leukocyte viability. The amount of adherent and phagocytosed bacteria as determined by flow cytometry was not influenced in cells only pretreated with PFH for 1 and 4 h. When PFH was present during E. coli challenge, bacterial adherence was decreased in polymorphonuclear neutrophils, but respective intracellular uptake was not impaired and was even significantly promoted in monocytes. Overall, E. coli-induced respiratory burst capacity was not reduced by PFH. Our findings provide evidence that key functions of innate host defense are not compromised by PFH treatment in vitro.

scholarly journals OXA-48 Carbapenemase-Encoding Transferable Plasmids of Klebsiella pneumoniae Recovered from Egyptian Patients Suffering from Complicated Urinary Tract Infections

Biology ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 889
Author(s):  
Ann A. Elshamy ◽  
Sarra E. Saleh ◽  
Mohammad Y. Alshahrani ◽  
Khaled M. Aboshanab ◽  
Mohammad M. Aboulwafa ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Antimicrobial Agents ◽  
Bacterial Species ◽  
Tertiary Care ◽  
Carbapenem Resistance ◽  
Clinical Isolates ◽  
Gram Negative ◽  
E Coli ◽  
Tract Infections

Gram-negative bacteria are common causes of urinary tract infections (UTIs). Such pathogens can acquire genes encoding multiple mechanisms of antimicrobial resistance, including carbapenem resistance. The aim of this study was to detect the carbapenemase-producing ability of some Gram-negative bacterial isolates from urine specimens of patients suffering from complicated UTIs at two vital tertiary care hospitals in Cairo, Egypt; to determine the prevalence of carbapenemase genes among plasmid-bearing isolates; and explore the possibility of horizontal gene transfer to other bacterial species. The collected isolates were subjected to antimicrobial susceptibility testing, phenotypic analysis of carbapenemase production, and molecular detection of plasmid-borne carbapenemase genes, then the extracted plasmids were transformed into competent E. coli DH5α. A total of 256 Gram-negative bacterial clinical isolates were collected, 65 (25.4%) isolates showed carbapenem resistance of which 36 (55.4%) were carbapenemase-producers, and of these 31 (47.7%) harbored plasmids. The extracted plasmids were used as templates for PCR amplification of blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP carbapenemase genes. The blaOXA-48 gene was detected in 24 (77.4%) of the tested isolates while blaVIM gene was detected in 8 (25.8%), both blaKPC and blaNDM genes were co-present in 1 (3.2%) isolate. Plasmids carrying the blaOXA-48 gene from 4 K. pneumoniae clinical isolates were successfully transformed into competent E. coli DH5α. The transformants were carbapenemase-producers and acquired resistance to some of the tested antimicrobial agents as compared to untransformed E. coli DH5α. The study concluded that the rate of carbapenem resistance among Gram-negative bacterial uropathogens in Cairo, Egypt is relatively high and can be transferred horizontally to other bacterial host(s).

Effect of TrisEDTA and Chlorhexidine 0.12% on an In Vitro-Defined Biofilm Representing the Subgingival Plaque Biofilm of the Dog

2021 ◽  
pp. 089875642110584
Author(s):  
Katherine E. Kling ◽  
Carol W. Maddox ◽  
Sandra Manfra Marretta ◽  
Christina Nowicki ◽  
David J. Schaeffer
Keyword(s):  
In Vitro Model ◽  
Complex Dynamics ◽  
Bacterial Species ◽  
Test Solution ◽  
Deionized Water ◽  
Subgingival Plaque ◽  
Biofilm Model ◽  
Vitro Model ◽  
Plaque Biofilm

This study was designed to investigate the effects of chlorhexidine 0.12%, TrisEDTA (tromethamine ethylenediamintetraacetic acid), and a combination of chlorhexidine 0.12% and TrisEDTA on an in vitro plaque biofilm model comprised of three bacterial species commonly found in canine subgingival plaque. Porphyromonas gulae, Actinomyces canis, and Neisseria canis were grown in a biofilm on polished hydroxyapatite coated titanium alloy pucks for 72 h prior to exposure to one of four test solutions: TrisEDTA, chlorhexidine 0.12%, a combination of TrisEDTA and chlorhexidine 0.12%, or sterile deionized water as a control. Following exposure to the test solution, a sample was collected of the biofilm either immediately or following 24 h of additional incubation in a broth medium. Lower numbers of CFU/mL of Porphyromonas gulae resulted when the biofilm was treated with a solution of chlorhexidine 0.12% and TrisEDTA compared to with chlorhexidine 0.12% alone, TrisEDTA alone, or the control and so this solution can be said to be synergistic against Porphyromonas gulae in this controlled in vitro model. Greater reductions in the numbers of CFU/mL of Actinomyces canis and Neisseria canis resulted from treatment with chlorhexidine 0.12% alone than if treated with the combination of TrisEDTA and chlorhexidine 0.12%. When treated biofilm samples were allowed 24 h of additional growth in fresh media, greater variance resulted and this variance highlights the complex dynamics involved in bacterial growth within a biofilm.

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.

scholarly journals Nanodiamonds facilitate killing of intracellular uropathogenic E. coli in an in vitro model of urinary tract infection pathogenesis

PLoS ONE ◽  
2018 ◽  
Vol 13 (1) ◽  
pp. e0191020 ◽  
Author(s):  
Janaki Kannan Iyer ◽  
Alexia Dickey ◽  
Parvaneh Rouhani ◽  
Anil Kaul ◽  
Nirmal Govindaraju ◽  
...  
Keyword(s):  
Urinary Tract Infection ◽  
Urinary Tract ◽  
Tract Infection ◽  
In Vitro Model ◽  
E Coli ◽  
Vitro Model

scholarly journals Antistaphylococcal Effect Related to the Area under the Curve/MIC Ratio in an In Vitro Dynamic Model: Predicted Breakpoints versus Clinically Achievable Values for Seven Fluoroquinolones

2005 ◽  
Vol 49 (7) ◽  
pp. 2642-2647 ◽  
Author(s):  
Alexander A. Firsov ◽  
Irene Y. Lubenko ◽  
Sergey N. Vostrov ◽  
Yury A. Portnoy ◽  
Stephen H. Zinner
Keyword(s):  
In Vitro Model ◽  
Therapeutic Potential ◽  
Area Under The Curve ◽  
Antimicrobial Effect ◽  
Clinical Isolates ◽  
Clinical Settings ◽  
Time Curve ◽  
Concentration Time ◽  
Vitro Model

ABSTRACT Prediction of the relative efficacies of different fluoroquinolones is often based on the ratios of the clinically achievable area under the concentration-time curve (AUC) to the MIC, usually with incorporation of the MIC50 or the MIC90 and with the assumption of antibiotic-independent patterns of the AUC/MIC-response relationships. To ascertain whether this assumption is correct, the pharmacodynamics of seven pharmacokinetically different quinolones against two clinical isolates of Staphylococcus aureus were studied by using an in vitro model. Two differentially susceptible clinical isolates of S. aureus were exposed to two 12-h doses of ciprofloxacin (CIP) and one dose of gatifloxacin (GAT), gemifloxacin (GEM), grepafloxacin (GRX), levofloxacin (LVX), moxifloxacin (MXF), and trovafloxacin (TVA) over similar AUC/MIC ranges from 58 to 932 h. A specific bacterial strain-independent AUC/MIC relationship with the antimicrobial effect (IE ) was associated with each quinolone. Based on the IE -log AUC/MIC relationships, breakpoints (BPs) that are equivalent to a CIP AUC/MIC ratio of 125 h were predicted for GRX, MXF, and TVA (75 to 78 h), GAT and GEM (95 to 103 h) and LVX (115 h). With GRX and LVX, the predicted BPs were close to those established in clinical settings (no clinical data on other quinolones are available in the literature). To determine if the predicted AUC/MIC BPs are achievable at clinical doses, i.e., at the therapeutic AUCs (AUCthers), the AUCther/MIC50 ratios were studied. These ratios exceeded the BPs for GAT, GEM, GRX, MXF, TVA, and LVX (750 mg) but not for CIP and LVX (500 mg). AUC/MIC ratios above the BPs can be considered of therapeutic potential for the quinolones. The highest ratios of AUCther/MIC50 to BP were achieved with TVA, MXF, and GEM (2.5 to 3.0); intermediate ratios (1.5 to 1.6) were achieved with GAT and GRX; and minimal ratios (0.3 to 1.2) were achieved with CIP and LVX.

scholarly journals Determination of Antibiotic Effect in an In Vitro Pharmacodynamic Model: Comparison with an Established Animal Model of Infection

2002 ◽  
Vol 46 (11) ◽  
pp. 3574-3579 ◽  
Author(s):  
Charles R. Bonapace ◽  
Lawrence V. Friedrich ◽  
John A. Bosso ◽  
Roger L. White
Keyword(s):  
Animal Model ◽  
Animal Models ◽  
In Vitro Model ◽  
Pharmacodynamic Model ◽  
Maximum Effect ◽  
Infection Model ◽  
Regression Equations ◽  
Antibiotic Effect ◽  
Vitro Model

ABSTRACT Animal infection models have historically been used to study pharmacodynamic relationships. Similar results could theoretically be produced by using an in vitro pharmacodynamic model as an alternative to animal models. We compared the antibiotic effects of ticarcillin administered in various doses and dosing regimens against Pseudomonas aeruginosa ATCC 27853 under conditions analogous to those previously employed in a neutropenic-mouse thigh infection model (B. Vogelman et al., J. Infect. Dis. 158:831-847, 1988). Ticarcillin dosages of either 96, 192, or 384 mg/day were administered at 1-, 2-, 3-, 4-, 8-, 12-, or 24-h intervals into a two-compartment model in order to duplicate the concentration-time profiles of the animal model. Colony counts were enumerated at 0 and 24 h. Linear regression and sigmoidal maximum-effect (Emax) model fitting were used to assess the relationship between the percentage of time that the concentration remained above the MIC (%T>MIC) or above four times the MIC (%T>4×MIC) and the change in the log10 CFU per milliliter (Δlog10 CFU/ml) in the central and peripheral compartments. Statistical analysis of the Δlog10 CFU/ml values was performed for matched regimens of the in vitro and animal models based on the %T>MICs. The slopes of the regression equations of %T>MICs relative to Δlog10 CFU/ml values were similar for the in vitro and animal models, but the y intercept was greater with the in vitro model. The Δlog10 CFU/ml values of the 0- to 24-h colony counts at equivalent %T>MICs in the two models were not statistically different (P = 0.087). Overall, the peripheral compartment of the in vitro model was a better predictor of effect than the central compartment. This study, which compares pharmacodynamic principles between an in vitro and an animal model, demonstrated similar relationships between %T>MICs and effects.

Sign in / Sign up

Export Citation Format

Share Document