scholarly journals Development of Rifapentine Susceptibility Tests forMycobacterium tuberculosis

1999 ◽  
Vol 43 (1) ◽  
pp. 25-28 ◽  
Author(s):  
L. Heifets ◽  
T. Sanchez ◽  
J. Vanderkolk ◽  
V. Pham
Keyword(s):  
Quality Control ◽  
Mycobacterium Tuberculosis ◽  
Resistant Strain ◽  
Clinical Laboratory ◽  
Critical Concentration ◽  
Culture Collection ◽  
American Type Culture Collection ◽  
Proportion Method ◽  
Susceptibility Tests

ABSTRACT Two methods for testing the susceptibility of Mycobacterium tuberculosis to rifapentine have been developed: the agar proportion method and the radiometric BACTEC technique. A critical concentration of 0.5 μg of rifapentine per ml is proposed for both methods since it provides a reliable means of distinguishing between susceptible and resistant M. tuberculosis isolates. It is recommended that two quality control M. tuberculosisstrains be used at the introduction of these tests in a clinical laboratory: one that is pansusceptible (H37Rv) and one that is resistant to rifapentine. The resistant strain can be obtained from the American Type Culture Collection, where it is deposited under the number ATCC 700457.

Determination of the Critical Concentration of Rifabutin for Susceptibility Testing Using the Proportion Method with Löwenstein-Jensen Medium against Mycobacterium Tuberculosis Isolates

2019 ◽  
Vol 50 (3) ◽  
pp. 292-297
Author(s):  
Guangming Dai ◽  
Suting Chen ◽  
Lingling Dong ◽  
Yun Xu Li ◽  
Fengmin Huo ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Critical Concentration ◽  
Reference Method ◽  
Cross Resistance ◽  
Lowenstein Jensen ◽  
Proportion Method ◽  
Antimicrobial Assay

AbstractObjectiveTo determine the critical concentration of rifabutin (RFB) for susceptibility testing against Mycobacterium tuberculosis (Mtb) on Löwenstein-Jensen (L-J) medium using the proportion method.MethodsWe used 47 strains were used to determine the critical concentration of RFB. The microplate antimicrobial assay (MABA) was used as a reference method. We used 160 strains to evaluate its correlation with the classification results derived from the MABA method. We performed antimicrobial susceptibility testing (AST) against RFB and rifampin (RIF) for 2748 other strains using the proportion method on L-J medium.ResultsThe determined critical concentration for RFB was 20 μg per mL. Identical classification as susceptible or resistant was observed in 93.8% and 92.5% strains for RFB and RIF, respectively, using the 2 different methods. The cross-resistance ratio between RFB and RIF was 72.7% in the 2748 Mtb strains.ConclusionsWe determined that a critical concentration of 20 μg per mL RFB was reliable for AST of Mtb.

scholarly journals Quality Control Guidelines for Disk Diffusion and Broth Microdilution Antimicrobial Susceptibility Tests with Seven Drugs for Veterinary Applications

2000 ◽  
Vol 38 (1) ◽  
pp. 453-455
Author(s):  
Brant A. Odland ◽  
Meredith E. Erwin ◽  
Ronald N. Jones
Keyword(s):  
Quality Control ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Disk Diffusion ◽  
National Committee ◽  
Broth Microdilution ◽  
E Coli ◽  
Antimicrobial Susceptibility Tests ◽  
Susceptibility Tests

ABSTRACT This multicenter study proposes antimicrobial susceptibility (MIC and disk diffusion methods) quality control (QC) parameters for seven compounds utilized in veterinary health. Alexomycin, apramycin, tiamulin, tilmicosin, and tylosin were tested by broth microdilution against various National Committee for Clinical Laboratory Standards (NCCLS)-recommended QC organisms ( Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Streptococcus pneumoniae ATCC 49619, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853). In addition, disk diffusion zone diameter QC limits were determined for apramycin, enrofloxacin, and premafloxacin by using E. coli ATCC 25922, P. aeruginosa ATCC 27853, and S. aureus ATCC 25923. The results from five or six participating laboratories produced ≥99.0% of MICs and ≥95.0% of the zone diameters within suggested guidelines. The NCCLS Subcommittee for Veterinary Antimicrobial Susceptibility Testing has recently approved these ranges for publication in the next M31 document.

scholarly journals Quality Control Limits for Broth Microdilution Susceptibility Tests of Ten Antifungal Agents

2000 ◽  
Vol 38 (9) ◽  
pp. 3457-3459 ◽  
Author(s):  
A. L. Barry ◽  
M. A. Pfaller ◽  
S. D. Brown ◽  
A. Espinel-Ingroff ◽  
M. A. Ghannoum ◽  
...  
Keyword(s):  
Quality Control ◽  
Antifungal Agents ◽  
Candida Parapsilosis ◽  
Clinical Laboratory ◽  
Collaborative Study ◽  
Candida Krusei ◽  
National Committee ◽  
Broth Microdilution ◽  
Susceptibility Tests ◽  
Control Limits

Broth microdilution susceptibility tests of Candidaspecies have now been standardized by the National Committee for Clinical Laboratory Standards (NCCLS). An eight-laboratory collaborative study was carried out in order to document reproducibility of tests of Candida parapsilosis ATCC 22019 and Candida krusei ATCC 6258 by the NCCLS method. Replicate broth microdilution tests were used to define control limits for 24- and 48-h MICs of amphotericin B, flucytosine, fluconazole, voriconazole, ketoconazole, itraconazole, caspofungin (MK 0991), ravuconazole (BMS 207147), posaconazole (SCH 56592), and LY 303366.

scholarly journals Correlation between GyrA Substitutions and Ofloxacin, Levofloxacin, and Moxifloxacin Cross-Resistance in Mycobacterium tuberculosis

2015 ◽  
Vol 59 (9) ◽  
pp. 5427-5434 ◽  
Author(s):  
Melisa Willby ◽  
R. David Sikes ◽  
Seidu Malik ◽  
Beverly Metchock ◽  
James E. Posey
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Critical Concentration ◽  
Drug Susceptibility ◽  
Drug Susceptibility Testing ◽  
Cross Resistance ◽  
Content Type ◽  
Treatment Regimens ◽  
Testing Susceptibility ◽  
Proportion Method ◽  
Reflex Testing

ABSTRACTThe newer fluoroquinolones moxifloxacin (MXF) and levofloxacin (LVX) are becoming more common components of tuberculosis (TB) treatment regimens. However, the critical concentrations for testing susceptibility ofMycobacterium tuberculosisto MXF and LVX are not yet well established. Additionally, the degree of cross-resistance between ofloxacin (OFX) and these newer fluoroquinolones has not been thoroughly investigated. In this study, the MICs for MXF and LVX and susceptibility to the critical concentration of OFX were determined using the agar proportion method for 133 isolates ofM. tuberculosis. Most isolates resistant to OFX had LVX MICs of >1 μg/ml and MXF MICs of >0.5 μg/ml. The presence of mutations within thegyrAquinolone resistance-determining regions (QRDR) correlated well with increased MICs, and the level of LVX and MXF resistance was dependent on the specificgyrAmutation present. Substitutions Ala90Val, Asp94Ala, and Asp94Tyr resulted in low-level MXF resistance (MICs were >0.5 but ≤2 μg/ml), while other mutations led to MXF MICs of >2 μg/ml. Based on these results, a critical concentration of 1 μg/ml is suggested for LVX and 0.5 μg/ml for MXF drug susceptibility testing by agar proportion with reflex testing for MXF at 2 μg/ml.

scholarly journals Kanamycin Susceptibility Testing of Mycobacterium tuberculosis Using Mycobacterium Growth Indicator Tube and a Colorimetric Method

2001 ◽  
Vol 45 (6) ◽  
pp. 1934-1936 ◽  
Author(s):  
Ivan Bastian ◽  
Leen Rigouts ◽  
Juan Carlos Palomino ◽  
Françoise Portaels
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Susceptibility Testing ◽  
Colorimetric Method ◽  
Alamar Blue ◽  
Mycobacterium Growth Indicator Tube ◽  
Indicator Tube ◽  
Proportion Method ◽  
Susceptibility Tests ◽  
Growth Indicator

ABSTRACT Two novel systems were evaluated for performing indirect kanamycin susceptibility tests on 72 strains of Mycobacterium tuberculosis. The microplate Alamar blue colorimetric method (breakpoint, 2.5 μg/ml) and the Mycobacterium Growth Indicator Tube (MGIT) system (breakpoint, 5.0 μg/ml) both produced 98.6% agreement when compared with the conventional proportion method performed on 7H10 agar using 5.0 μg of kanamycin/ml. Both systems provided results within an average of 1 week.

scholarly journals Resazurin Microtiter Assay Plate Testing of Mycobacterium tuberculosis Susceptibilities to Second-Line Drugs: Rapid, Simple, and Inexpensive Method

2003 ◽  
Vol 47 (11) ◽  
pp. 3616-3619 ◽  
Author(s):  
Anandi Martin ◽  
Mirtha Camacho ◽  
Françoise Portaels ◽  
Juan Carlos Palomino
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Drug Susceptibility ◽  
Multidrug Resistant ◽  
Second Line ◽  
Aminosalicylic Acid ◽  
Resistant Tuberculosis ◽  
Proportion Method ◽  
Susceptibility Tests ◽  
Visual Reading ◽  
Microtiter Assay

ABSTRACT The emergence of multidrug-resistant tuberculosis calls for new, rapid drug susceptibility tests. We have tested 150 Mycobacterium tuberculosis isolates against the second-line drugs ethionamide, kanamycin, capreomycin, ofloxacin, and para-aminosalicylic acid by the colorimetric resazurin microtiter assay and the proportion method. By visual reading, MICs were obtained after 8 days. A very good correlation between results by the colorimetric resazurin microtiter assay and the proportion method was obtained. The colorimetric resazurin microtiter assay is inexpensive, rapid, and simple to perform, and implementation of the assay is feasible for low-resource countries.

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