Short-term in vitro culture ofPlasmodium vivax andP. ovale for drug-susceptibility testing

1994 ◽  
Vol 80 (3) ◽  
pp. 262-264 ◽  
Author(s):  
L. K. Basco ◽  
J. Le Bras
Keyword(s):  
In Vitro Culture ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Short Term

scholarly journals Pyrazinamide Is Active against Mycobacterium tuberculosis Cultures at Neutral pH and Low Temperature

2016 ◽  
Vol 60 (8) ◽  
pp. 4956-4960 ◽  
Author(s):  
Alice L. den Hertog ◽  
Sandra Menting ◽  
Richard Pfeltz ◽  
Matthew Warns ◽  
Salman H. Siddiqi ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Low Temperature ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Acidic Ph ◽  
Content Type ◽  
The Past ◽  
Neutral Ph

ABSTRACTFor the past decades, an acidic pH has been used to renderMycobacterium tuberculosissusceptible to pyrazinamide forin vitrotesting. Here, we show that at the standard breakpoint concentration and reduced culture temperatures, pyrazinamide (PZA) is active against tuberculosis (TB) at neutral pH. This finding should help unravel the mechanism of action of PZA and allow drug susceptibility testing (DST) methods to be optimized.

scholarly journals New Approach for Drug Susceptibility Testing: Monitoring the Stress Response of Mycobacteria

2009 ◽  
Vol 53 (11) ◽  
pp. 4598-4603 ◽  
Author(s):  
Ronald J. Rieder ◽  
Zhihui Zhao ◽  
Boris Zavizion
Keyword(s):  
Susceptibility Testing ◽  
Physiological Stress ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Bacterial Suspension ◽  
Prolonged Incubation ◽  
New Approach ◽  
Induced Stress ◽  
In Vitro Drug Susceptibility

ABSTRACT Methods currently used for in vitro drug susceptibility testing are based on the assessment of bacterial growth-related processes. This reliance on cellular reproduction leads to prolonged incubation times, particularly for slowly growing organisms such as mycobacteria. A new rapid phenotypic method for the drug susceptibility testing of mycobacteria is described. The method is based on the detection of the physiological stress developed by susceptible mycobacterial cells in the presence of an antimicrobial compound. The induced stress was quantified by differential monitoring of the dielectric properties of the bacterial suspension, an easily measurable electronic property. The data presented here characterize the stress developed by Mycobacterium tuberculosis cells treated with rifampin (rifampicin), isoniazid, ethambutol, and pyrazinamide. Changes in the dielectric-based profiles of the drug-treated bacteria revealed the respective susceptibilities in near real time, and the susceptibilities were well correlated with conventional susceptibility test data.

scholarly journals Interpreting Susceptibility Testing of Carbapenem Against Pseudomonas aeruginosa

2016 ◽  
Vol 4 (1) ◽  
pp. 1-8
Author(s):  
Maite Micaelo ◽  
Florence Brossier ◽  
Nicolas Brechot ◽  
Charles Edouard Luyt ◽  
Qin Lu ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Diffusion Method ◽  
Disc Diffusion ◽  
Limited Data ◽  
Disc Diffusion Method ◽  
New Guidelines

Objectives: Carbapenems are among the most powerful anti pseudomonal agents. Since meropenem and doripenem were marketed, there are limited data regarding drug susceptibility testing by routine methods (disc diffusion and Etest) for them. The aim of our study was to compare in vitro activity of the imipenem, meropenem and doripenem against Pseudomonas aeruginosa. Methods: Three hundred and eleven P. aeruginosa strains isolated from respiratory specimens in 170 patients who developed ventilator-associated pneumonia in two intensive care units were collected over a period of 31 months. The susceptibility of all of these isolates to imipenem, meropenem and doripenem were determined by Etest and disc diffusion method. Results: Considering either all of the isolates or only the first isolates recovered per patient (311 and 170 respectively) the susceptibility rate for doripenem was higher than that for meropenem and imipenem. When MICs determined by Etest were converted into interpretative categories (S, I, R) using French (CA-SFM) guidelines, agreement was poor, especially for meropenem and doripenem. The percent of agreement with the disc diffusion method were 90.6% and 89.7% for imipenem, 80.5% and 82.6% for meropenem and 80.5% and 73.3% for doripenem, for the first isolates and all of the isolates, respectively. Errors were mostly minor errors, and the rate of errors was as high as 17.7% and 16.1% for meropenem and 17.7% and 25.7% for doripenem for the first isolates and all of the isolates, respectively Conclusion: The accuracy of disc diffusion using CA-SFM guidelines appears unsatisfactory for all the three carbapenems justifying the adaptation of new guidelines for P. aeruginosa and carbapenems

Evaluation of high-throughput assays for in vitro drug susceptibility testing of Tritrichomonas foetus trophozoites

2016 ◽  
Vol 223 ◽  
pp. 34-37 ◽  
Author(s):  
Chris Bader ◽  
Jeba Jesudoss Chelladurai ◽  
Kylie Thompson ◽  
Cindy Hall ◽  
Steve A. Carlson ◽  
...  
Keyword(s):  
High Throughput ◽  
Susceptibility Testing ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Tritrichomonas Foetus ◽  
In Vitro Drug Susceptibility

scholarly journals The Trailing End Point Phenotype in Antifungal Susceptibility Testing Is pH Dependent

1999 ◽  
Vol 43 (6) ◽  
pp. 1383-1386 ◽  
Author(s):  
Kieren A. Marr ◽  
Tige R. Rustad ◽  
John H. Rex ◽  
Theodore C. White
Keyword(s):  
Minimal Medium ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Ph Effect ◽  
Antifungal Susceptibility ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
National Committee ◽  
End Points

ABSTRACT The interpretation of end points in azole antifungal drug susceptibility testing is problematic, in part due to incomplete growth inhibition of Candida species. Such trailing growth can cause the MICs of fluconazole for some isolates to be low (<1 μg/ml) after 24 h of growth but much higher (>64 μg/ml) after 48 h. Isolates having this type of growth have been described as having a low-high phenotype. Although these isolates would be considered resistant by current National Committee of Clinical Laboratory Standards definitions, growing evidence suggests that they are susceptible in vivo. To further characterize these isolates in vitro, microdilution susceptibility testing comparing the complex defined medium RPMI 1640 to a defined minimal medium (yeast nitrogen broth) was performed. Isolates having trailing growth in MOPS (morpholinepropanesulfonic acid)-buffered RPMI 1640 (pH 7.0) were found to have clear end points in the minimal medium at its native pH of 4.5. The pH of the medium influenced the low-high phenotype, as these same isolates trailed in minimal medium adjusted to a pH of ≥6.0 but did not trail in RPMI 1640 adjusted to a pH of ≤5.0. This pH effect was independent of the medium buffering capacity, as trailing was decreased in both minimal medium and RPMI 1640 (pH 4.5) buffered in citrate. Adjustment in the pH of MOPS-buffered RPMI 1640 reduced trailing in multiple strains of Candida albicans without affecting the MICs for isolates having known susceptible (low-low) and resistant (high-high) phenotypes. Adjustment of the medium pH could be considered to eliminate trailing in azole drug susceptibility testing.

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