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Mishra R, Shukla P, Huang W, Hu N. Gene mutations in Mycobacterium tuberculosis: multidrug-resistant TB as an emerging global public health crisis. Tuberculosis (Edinb) 2014; 95:1-5. [PMID: 25257261 DOI: 10.1016/j.tube.2014.08.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2014] [Accepted: 08/22/2014] [Indexed: 11/27/2022]
Abstract
Against a constant background of established infections, epidemics of new and old infectious diseases periodically emerge, greatly magnifying the global burden of infections. TB poses formidable challenges to the global health at the public health and scientific level by acquiring gene mutation into anti TB drugs specially rifampin and isoniazid which leads resistant to drug regime and treatment forms. Our tools to combat MDR (multidrug resistant) TB are dangerously out of date and ineffective. Besides new tools (TB drugs, vaccines, diagnostics), we also need new strategies to identify key Mycobacterium tuberculosis and human host interaction. It is all equally important that we build up high quality clinical trial capacity and bio banks for TB biomarkers identification. But most important is global commitment at all levels to roll back TB before it expose us again. Rapid development of drug resistance caused by M. tuberculosis has lead to measure resistance accurately and easily. This knowledge will certainly help us to understand how to prevent the occurrence of drug resistance as well as identifying genes associated with new drug resistance.
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Affiliation(s)
- Rahul Mishra
- First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Priyanka Shukla
- First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Wei Huang
- First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
| | - Ning Hu
- First Affiliated Hospital of Chongqing Medical University, Chongqing, China.
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Mehta A, Srivastva G, Kachhwaha S, Sharma M, Kothari SL. Antimycobacterial activity of Citrullus colocynthis (L.) Schrad. against drug sensitive and drug resistant Mycobacterium tuberculosis and MOTT clinical isolates. JOURNAL OF ETHNOPHARMACOLOGY 2013; 149:195-200. [PMID: 23816500 DOI: 10.1016/j.jep.2013.06.022] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Revised: 05/31/2013] [Accepted: 06/14/2013] [Indexed: 06/02/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Citrullus colocynthis (Cucurbitaceae), a folk herbal medicine and traditionally used natural remedy for tuberculosis in India has been studied to validate its antitubercular activity against drug sensitive and drug resistant (including multidrug resistant) Mycobacterium tuberculosis and Mycobacterium other than tuberculosis (MOTT) bacilli. MATERIALS AND METHODS Inhibitory and bactericidal activities of crude extracts, fractions and compounds of Citrullus colocynthis plant, consisting of aerial parts and ripe deseeded fruits were performed against the drug sensitive standard strain of Mycobacterium tuberculosis H37Rv (ATCC 27294), 16 drug resistant strains of Mycobacterium tuberculosis and two MOTT strains, using radiometric BACTEC 460TB system. RESULTS Methanolic extract of ripe deseeded fruit of Citrullus colocynthis has shown good activity (MIC ≤ 62.5 µg/ml), whereas among the bioactive fractions, FC IX demonstrated the best activity (MIC 31.2 µg/ml) against Mycobacterium tuberculosis H37Rv. Bioactive FC III, IX and X also inhibited 16 clinical isolates of Mycobacterium tuberculosis consisting of seven non-multidrug resistants, eight multidrug resistants, one extensively drug resistant and two of MOTTs with MICs in the range of 50-125, 31.2-125 and 62.5-125 µg/ml, respectively. Ursolic acid and cucurbitacin E 2-0-β-d-glucopyranoside were identified as the main biomarkers active against Mycobacterium tuberculosis H37Rv (MICs 50 and 25 µg/ml respectively), as well as against the 18 clinical isolates. FC III and FC IX showed better inhibition of drug resistant and MOTT clinical isolates. Minimal bactericidal concentrations of extracts, fractions and compound C-2 were ≥ two-fold MIC values. CONCLUSIONS The study provides a scientific rationale for the traditional use of Citrullus colocynthis fruit in the treatment of tuberculosis. In addition, the study elucidates a broad spectrum antimycobacterial action of Citrullus colocynthis fruit, which can contribute to the development of improved preparation of an antitubercular natural drug for the treatment of drug resistant tuberculosis and MOTT infection as well.
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Affiliation(s)
- Archana Mehta
- Department of Botany, University of Rajasthan, Jaipur 302004, India
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Synergistic Antimycobacterial Actions of Knowltonia vesicatoria (L.f) Sims. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2012; 2012:808979. [PMID: 22611433 PMCID: PMC3352337 DOI: 10.1155/2012/808979] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Accepted: 02/19/2012] [Indexed: 11/30/2022]
Abstract
Euclea natalensis A.DC., Knowltonia vesicatoria (L.f) Sims, and Pelargonium sidoides DC. are South African plants traditionally used to treat tuberculosis. Extracts from these plants were used in combination with isoniazid (INH) to investigate the possibility of synergy with respect to antimycobacterial activity. The ethanol extract of K. vesicatoria was subjected to fractionation to identify the active compounds. The activity of the Knowltonia extract remained superior to the fractions with a minimum inhibitory concentration (MIC) of 625.0 μg/mL against Mycobacterium smegmatis and an MIC of 50.00 μg/mL against M. tuberculosis. The K. vesicatoria extract was tested against two different drug-resistant strains of M. tuberculosis, which resulted in an MIC of 50.00 μg/mL on both strains. The combination of K. vesicatoria with INH exhibited the best synergistic antimycobacterial activity with a fractional inhibitory concentration index of 0.25 (a combined concentration of 6.28 μg/mL). A fifty percent inhibitory concentration of this combination against U937 cells was 121.0 μg/mL. Two compounds, stigmasta-5,23-dien-3-ol (1) and 5-(hydroxymethyl)furan-2(5H)-one (2), were isolated from K. vesicatoria as the first report of isolation for both compounds from this plant and the first report of antimycobacterial activity. Compound (1) was active against drug-sensitive M. tuberculosis with an MIC of 50.00 μg/mL.
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Evaluation of the VersaTREK system compared to the Bactec MGIT 960 system for first-line drug susceptibility testing of Mycobacterium tuberculosis. J Clin Microbiol 2011; 50:488-91. [PMID: 22135258 DOI: 10.1128/jcm.06432-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The aim of this study was to evaluate the reliability of the VersaTREK system for Mycobacterium tuberculosis drug susceptibility testing compared with results obtained with the Bactec MGIT 960 system. A total of 67 strains were evaluated. Overall agreement was at 98.5%. Kappa indexes were 1.0 for isoniazid, rifampin, and ethambutol, 0.937 for pyrazinamide, and 0.907 for streptomycin. The VersaTREK system is validated for M. tuberculosis drug susceptibility testing.
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Development of a rapid ATP bioluminescence assay for biocidal susceptibility testing of rapidly growing mycobacteria. J Clin Microbiol 2010; 48:3725-8. [PMID: 20720030 DOI: 10.1128/jcm.01482-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An ATP-based biocide susceptibility assay for mycobacteria was developed by optimizing the cell lysis and assay conditions. Compared to the conventional agar plating method, the assay was rapid (1.5 h) and showed high sensitivity and specificity as determined by receiver operating characteristic (ROC) analysis. The test species, Mycobacterium immunogenum, M. chelonae, and M. abscessus, showed various susceptibilities to the glutaraldehyde- and isothiazolone-based test biocides.
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Granieri L, Miller OJ, Griffiths AD, Merten CA. A competition-based assay for the screening of species-specific antibiotics. J Antimicrob Chemother 2009; 64:62-8. [DOI: 10.1093/jac/dkp137] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Gupta VK, Fatima A, Faridi U, Negi AS, Shanker K, Kumar JK, Rahuja N, Luqman S, Sisodia BS, Saikia D, Darokar MP, Khanuja SPS. Antimicrobial potential of Glycyrrhiza glabra roots. JOURNAL OF ETHNOPHARMACOLOGY 2008; 116:377-80. [PMID: 18182260 DOI: 10.1016/j.jep.2007.11.037] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 07/16/2007] [Accepted: 11/27/2007] [Indexed: 05/20/2023]
Abstract
The present study was aimed to investigate antimicrobial potential of Glycyrrhiza glabra roots. Antimycobacterial activity of Glycyrrhiza glabra was found at 500 microg/mL concentration. Bioactivity guided phytochemical analysis identified glabridin as potentially active against both Mycobacterium tuberculosis H(37)Ra and H(37)Rv strains at 29.16 microg/mL concentration. It exhibited antimicrobial activity against both Gram-positive and Gram-negative bacteria. Our results indicate potential use of licorice as antitubercular agent through systemic experiments and sophisticated anti-TB assay.
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Affiliation(s)
- Vivek K Gupta
- Genetic Resources and Biotechnology Division, Central Institute of Medicinal and Aromatic Plants (CSIR), Kukrail Picnic Spot Road, P.O. CIMAP, Lucknow 226015, India
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Garrigó M, Aragón LM, Alcaide F, Borrell S, Cardeñosa E, Galán JJ, Gonzalez-Martín J, Martin-Casabona N, Moreno C, Salvado M, Coll P. Multicenter laboratory evaluation of the MB/BacT Mycobacterium detection system and the BACTEC MGIT 960 system in comparison with the BACTEC 460TB system for susceptibility testing of Mycobacterium tuberculosis. J Clin Microbiol 2007; 45:1766-70. [PMID: 17442793 PMCID: PMC1933104 DOI: 10.1128/jcm.02162-06] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In this multicenter study, the reliability of two nonradiometric, fully automated systems, the MB/BacT and BACTEC MGIT 960 systems, for testing the susceptibilities of 82 Mycobacterium tuberculosis strains to isoniazid, rifampin, ethambutol, and streptomycin was evaluated in comparison with the radiometric BACTEC 460TB system. The arbitration of discrepant results was done by the reanalysis of the strain, the determination of the MIC, and the molecular characterization of some resistance determinants. The overall level of agreement with BACTEC 460TB results was 96% with the MB/BacT test and 97.2% with the BACTEC MGIT 960 system. With both methods, the level of agreement with BACTEC 460TB results was 96.3% for isoniazid, 98.8% for rifampin, and 98.8% for ethambutol. The level of agreement for streptomycin was 90.2% with MB/BacT and 97.5% with BACTEC MGIT 960. Overall, there were 11 very major errors and 2 major errors with the MB/BacT method and 5 very major errors and 2 major errors with the BACTEC MGIT 960 system. In general, the MB/BacT and BACTEC MGIT 960 systems showed good performance for susceptibility testing with first-line antituberculosis drugs.
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Affiliation(s)
- Montserrat Garrigó
- Servei de Microbiologia, Hospital de la Santa Creu i Sant Pau, Av. Sant Antoni M Claret, 167, 08025 Barcelona, Spain
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Marsollier L, Honoré N, Legras P, Manceau AL, Kouakou H, Carbonnelle B, Cole ST. Isolation of three Mycobacterium ulcerans strains resistant to rifampin after experimental chemotherapy of mice. Antimicrob Agents Chemother 2003; 47:1228-32. [PMID: 12654651 PMCID: PMC152492 DOI: 10.1128/aac.47.4.1228-1232.2003] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
By use of a murine model for Buruli ulcer, Mycobacterium ulcerans was found to be susceptible to rifampin, with the MIC being 0.5 to 1 micro g/ml. Three mutants were isolated after rifampin monotherapy. Two were resistant to rifampin at 8 micro g/ml, and one was resistant to rifampin at 32 micro g/ml. The mutants harbored Ser416Phe mutations and His420Tyr mutations in the rpoB gene, and these mutations have also been found to be responsible for rifampin resistance in the leprosy and tubercle bacilli. The results indicate that while rifampin may be active against M. ulcerans, it should never be used as monotherapy in humans.
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Affiliation(s)
- Laurent Marsollier
- Laboratoire de Bactériologie-Virologie-Hygiène Hospitalière, CHU, 49033 Angers Cedex 01, France.
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Victor TC, Lee H, Cho SN, Jordaan AM, van der Spuy G, van Helden PD, Warren R. Molecular detection of early appearance of drug resistance during Mycobacterium tuberculosis infection. Clin Chem Lab Med 2002; 40:876-81. [PMID: 12435103 DOI: 10.1515/cclm.2002.155] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
During the early development of drug resistance in Mycobacterium tuberculosis (M. tuberculosis) infection only a small proportion of resistant bacteria are present within a milieu of sensitive bacteria. This complicates the use of molecular methods to predict the presence of a resistant phenotype and has been largely ignored in many of the newly developed molecular methods. In this study, mixtures of DNA from M. tuberculosis strains with known wild-type and mutant sequences were used to evaluate the sensitivity of three different molecular methods for detection of drug resistance. The dot-blot and amplification refractory mutation system (ARMS) methods showed sensitivities that approach those of routine phenotypic methods and are able to detect the presence of mutant sequences at a ratio of 1 in 50 (corresponding to 2% mutant sequences). This is 10-fold more sensitive than the commercial kit. The ARMS method was also used to investigate the use of molecular methods to identify mixed infections, and both drug-resistant and susceptible strain populations were identified in a single clinical isolate. These findings highlight the applicability of molecular methods to the rapid detection of drug resistance in tuberculosis patients, particularly in those who are non-compliant and in contacts of known drug-resistant tuberculosis patients, and assistance in limiting the spread of drug-resistant strains.
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Affiliation(s)
- Thomas C Victor
- MRC Center for Molecular and Cellular Biology, Department of Medical Biochemistry, University of Stellenbosch, Tygerberg, South Africa.
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Dhople AM. In vitro activity of KRM-1648, either singly or in combination with ofloxacin, against Mycobacterium ulcerans. Int J Antimicrob Agents 2001; 17:57-61. [PMID: 11137650 DOI: 10.1016/s0924-8579(00)00306-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The antimicrobial effect of a benzoxazinorifamycin, KRM-1648, either alone or in combination with ofloxacin, was evaluated in vitro against two type strains and six clinical isolates of Mycobacterium ulcerans. Growth of M. ulcerans was measured by plate counts and the BACTEC radiometric method. The minimal inhibitory concentration as well as minimal bactericidal concentration of KRM-1648 against M. ulcerans was between 0.012 and 0.025 mg/l, while corresponding values for rifampicin and rifabutin were in the range of 0.1-0.8 mg/l and 0.1-0.4 mg/l respectively. When combined with ofloxacin, KRM-1648 exhibited strong synergistic activity while only additive effects were observed with the combination of rifampicin (or rifabutin) and ofloxacin. These results suggest that KRM-1648 has a great potential in the treatment of M. ulcerans infection.
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Affiliation(s)
- A M Dhople
- Department of Biological Sciences, Florida Institute of Technology, Melbourne, FL 32901, USA.
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Bemer-Melchior P, Bryskier A, Drugeon HB. Comparison of the in vitro activities of rifapentine and rifampicin against Mycobacterium tuberculosis complex. J Antimicrob Chemother 2000; 46:571-6. [PMID: 11020254 DOI: 10.1093/jac/46.4.571] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The in vitro activity of rifapentine for 44 clinical isolates of Mycobacterium tuberculosis complex was compared with that of rifampicin using the Bactec radiometric method and the absolute concentration method for susceptibility testing. Twenty-nine M. tuberculosis, 11 Mycobacterium bovis and four Mycobacterium africanum strains were studied. Control tests showed that rifapentine was stable for 14 days in 7H9 broth and for 3 weeks in 7H10 agar medium. The 44 M. tuberculosis complex strains were more susceptible to rifapentine than to rifampicin, irrespective of the testing method. In the radiometric system, the MIC50 and MIC90 of rifapentine for M. tuberculosis complex strains were one or two two-fold dilutions lower than those of rifampicin (0.06-0.125 mg/L versus 0.25 mg/L, respectively). By the absolute concentration method, the MIC50 and MIC90 of rifapentine for M. tuberculosis complex strains were two two-fold dilutions lower than those of rifampicin (0.125-0.25 mg/L versus 0.5-1 mg/L, respectively). The MIC90 of rifapentine for the 44 M. tuberculosis complex strains was always 0.25 mg/L, irrespective of the method used, but the radiometric method was more reliable and more reproducible than the agar 7H10 method.
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Affiliation(s)
- P Bemer-Melchior
- Department of Microbiology, Laënnec University Hospital, Laënnec University Hospital, Bd J. Monod, 44093 Saint-Herblain cedex 1, Nantes, France.
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Victor TC, Jordaan AM, van Rie A, van der Spuy GD, Richardson M, van Helden PD, Warren R. Detection of mutations in drug resistance genes of Mycobacterium tuberculosis by a dot-blot hybridization strategy. TUBERCLE AND LUNG DISEASE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL UNION AGAINST TUBERCULOSIS AND LUNG DISEASE 2000; 79:343-8. [PMID: 10694978 DOI: 10.1054/tuld.1999.0222] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
SETTING Mycobacterium tuberculosis isolates from patients in communities endemic for tuberculosis in South Africa. OBJECTIVE To develop a reliable PCR-based dot-blot hybridization strategy to detect mutations conferring drug resistance. DESIGN Different loci in six genes associated with drug resistance to isoniazid, rifampacin, streptomycin and ethambutol were selected to develop the PCR-based dot-blot hybridization strategy. RESULTS Primers and probes to detect mutations at codons 315, 463 (katG) 269 (kasA), 531, 526 (rpoB) 43 (rpsL), 513 (rrs) and 306 (embB) were designed and used to develop a PCR-based dot-blot hybridization strategy. The dot-blot hybridization strategy with wild-type probes can efficiently be used to detect drug resistant mutations since these do not hybridize to mutant loci. Stripped blots and mutant probes can be used to identify the precise mutation. The embB gene (ethambutol resistance) was used to show how the dot-blot strategy can assist with the prediction of drug resistance more accurately. The method is rapid, reproducible, not technically demanding and samples can be done in batches. Additional loci can easily be incorporated. CONCLUSIONS A PCR-based dot-blot hybridization strategy is described which can accurately identify drug resistant strains and the method is useful for patients at risk and in areas endemic for tuberculosis.
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Affiliation(s)
- T C Victor
- Department of Medical Biochemistry, University of Stellenbosch, Medical School, South Africa.
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Mshana RN, Tadesse G, Abate G, Miörner H. Use of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide for rapid detection of rifampin-resistant Mycobacterium tuberculosis. J Clin Microbiol 1998; 36:1214-9. [PMID: 9574679 PMCID: PMC104802 DOI: 10.1128/jcm.36.5.1214-1219.1998] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
We describe a test which uses the ability of viable cells to reduce 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) to detect resistance to a bactericidal drug, rifampin, in in vitro-cultured Mycobacterium tuberculosis. The assay shows a linear relationship between the number of viable bacteria and the ability to reduce MTT. Dead mycobacteria were unable to reduce MTT. Rifampin-sensitive M. bovis (BCG) and M. tuberculosis exposed to rifampin showed a rifampin concentration-dependent inhibition of the ability to reduce MTT, while the resistant strains were unaffected. The inhibition of MTT reduction after treatment with rifampin paralleled the reduction in the number of CFU. By using mixing experiments in which the population percentages of rifampin-sensitive and -resistant strains were varied, the assay could detect the presence of rifampin resistance in the mixture when at least 1% of the bacterial population was composed of drug-resistant strains. The assay is cheap, can be visually read, and requires less than 3 days to obtain susceptibility results. The total time required to obtain results, from the time sputum is received in the laboratory, is, in most cases, less than 4 to 5 weeks, which is the time required for primary culture of the bacteria. The MTT assay could, in combination with a test to detect resistance to isoniazid, be a cheap and rapid screening method for multidrug-resistant M. tuberculosis that is affordable even by low-income countries where tuberculosis is a major public health problem.
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Affiliation(s)
- R N Mshana
- Armauer Hansen Research Institute, Addis Ababa, Ethiopia
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Martin-Casabona N, Xairó Mimó D, González T, Rossello J, Arcalis L. Rapid method for testing susceptibility of Mycobacterium tuberculosis by using DNA probes. J Clin Microbiol 1997; 35:2521-5. [PMID: 9316900 PMCID: PMC230003 DOI: 10.1128/jcm.35.10.2521-2525.1997] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The increasing number of multidrug-resistant Mycobacterium tuberculosis strains has stimulated the interest of investigators in finding a rapid method for susceptibility testing. We used commercially available rRNA DNA-bioluminescence-labelled probes (Accu-Probe, Gen Probe, Inc. San Diego, Calif.) for this purpose. The study was performed in three chronological steps. (i) We studied the correlation between the photometric light units (PLUs) given by the hybridization method, the numbers of CFU per milliliter, and turbidity as nephelometric units for six different inocula of an M. tuberculosis strain over 14 days. A good correlation (c > 0.9; P < 0.05) was found from the third day for all concentrations used. (ii) Over a period of 14 days we studied the evolution of the PLUs for 20 strains growing in medium with 0.2 microl of isoniazid (H) per ml and 18 strains in medium with 1 microl of rifampin (R) per ml to standardize the method. Susceptible and resistant strains were used according to the reference proportions method in Middlebrook 7H10, and the MICs were determined in solid and liquid media. The final inoculum of a 10(-2) dilution from a McFarland no. 1 standard and reading at 3 and 5 days provided the best results. A quotient was established to find a cutoff point between resistant and susceptible strains. (iii) We used the standardized parameters in 117 tests with H and R. On day 3, the sensitivity, specificity, positive predictive value, and negative predictive value for detecting resistant strains were 86.8, 100, 100, and 90.1%, respectively, and on day 5 they were 96.2, 100, 100, and 94%, respectively. We concluded that the method is readily available, is easy to perform, and could be useful for screening resistant M. tuberculosis strains.
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Affiliation(s)
- N Martin-Casabona
- Servei de Microbiologia i Parasitologia, Ciutat Sanitària Universitària Vall d'Hebron, Barcelona, Spain
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Comparative in vitro activities of rifamycin analogues against rifampin-sensitive and rifampin-resistant Mycobacterium tuberculosis. Int J Antimicrob Agents 1997; 8:209-14. [DOI: 10.1016/s0924-8579(97)00016-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/06/1997] [Indexed: 11/16/2022]
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Pineda-Garcia L, Ferrera A, Galvez CA, Hoffner SE. Drug-resistant Mycobacterium tuberculosis and atypical mycobacteria isolated from patients with suspected pulmonary tuberculosis in Honduras. Chest 1997; 111:148-53. [PMID: 8996009 DOI: 10.1378/chest.111.1.148] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Tuberculosis is a major health problem in Central America. In Honduras, with an incidence rate of 81/100,000, it is an increasingly common cause of morbidity and hospitalization. This study was conducted to examine drug-resistant tuberculosis and prevalence of infection with atypical mycobacteria in Honduran patients with suspected pulmonary tuberculosis. METHODS Pulmonary specimens from 235 Honduran patients with suspected tuberculosis were examined by acid-fast smears and culture. The 95 mycobacterial strains isolated were identified to species level and drug susceptibility tests were carried out. Resistant Mycobacterium tuberculosis strains were tested for susceptibility to six additional drugs. Their possible relationship was studied by DNA restriction fragment length polymorphism. RESULTS Drug-resistant strains were found in 13 of 85 culture-verified tuberculosis patients, including 10 with isolates of multidrug-resistant bacteria. Seven of the patients with multidrug-resistant tuberculosis had smear-positive disease. Nine of them had a history of specific therapy. Two patients with drug-resistant disease were shown to be infected by identical strains. Only one of 11 HIV-positive patients had drug-resistant tuberculosis. Most resistant strains were susceptible to ciprofloxacin, amikacin, kanamycin, and pyrazinamide. Atypical mycobacteria were isolated from 10 patients with suspected tuberculosis. Seven of them were receiving antituberculosis chemotherapy and five had smear-positive samples. CONCLUSIONS These results illustrate the importance of mycobacterial culture and subsequent species identification and in vitro susceptibility testing for identification of patients with drug-susceptible or drug-resistant tuberculosis and those infected or colonized with other mycobacteria.
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Affiliation(s)
- L Pineda-Garcia
- Department of Microbiology, Universidad Nacional Autonoma de Honduras, Tegucigalpa, Honduras
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Chung GA, Aktar Z, Jackson S, Duncan K. High-throughput screen for detecting antimycobacterial agents. Antimicrob Agents Chemother 1995; 39:2235-8. [PMID: 8619574 PMCID: PMC162921 DOI: 10.1128/aac.39.10.2235] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
A simple, robust assay system which can be used to screen for inhibitors of mycobacterial growth has been developed. A strain of the rapidly growing saprophyte Mycobacterium aurum is used as the test organism. Inhibition of its growth is highly predictive of activity against Mycobacterium tuberculosis, which cannot itself be used in screening because of its growth characteristics and highly infectious nature. The viability of M. aurum in the presence of a test sample is monitored by measuring the uptake of radiolabelled uracil into the cells. In a microtiter plate format, the screen has the potential for testing several thousand samples per day.
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Affiliation(s)
- G A Chung
- Glaxo Research and Development Ltd., Stevenage, Hertfordshire, United Kingdom
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Dhople AM, Dhople AA, Ibanez MA. In vitro activities of 2,2'-bipyridyl analogues against Mycobacterium avium and M. tuberculosis. TUBERCLE AND LUNG DISEASE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL UNION AGAINST TUBERCULOSIS AND LUNG DISEASE 1995; 76:136-40. [PMID: 7780096 DOI: 10.1016/0962-8479(95)90556-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
SETTING Because of widespread emergence of resistant Mycobacterium tuberculosis and the high incidence of opportunistic infection caused by M. avium (MAC) in AIDS patients, there is an urgent need for new drugs against these organisms. OBJECTIVE To evaluate the activity of newly synthesized 2,2'-bipyridyl analogues against MAC and M. tuberculosis. DESIGN Susceptibility of MAC and M. tuberculosis to VUF-8514 and VUF-8842 were determined by both tube dilution method using 7H9 broth and radiometric (BACTEC) method using 14C-palmitic acid. RESULTS AND CONCLUSIONS The MICs of 8514 against MAC and M. tuberculosis wee 1 microgram/ml and 0.5 microgram/ml respectively, while for 8842 the respective values were 8 micrograms/ml and 2 micrograms/ml. In general, the MBC values for both drugs were two-fold higher than their corresponding MIC values. However, both drugs exhibited high bactercidal activities against both organisms. The MICs of clinical isolates of both organisms were in the same range as reference strains; furthermore, two isolates of M. tuberculosis that showed resistance to rifampicin were found to be susceptible to 8514. Thus, these two bipyridyl analogues show great promise in chemotherapy of tuberculosis and M. avium infection.
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Affiliation(s)
- A M Dhople
- Department of Biological Sciences, Florida Institute of Technology, Melbourne 32901-6988, USA
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21
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Reddy MV, Srinivasan S, Andersen B, Gangadharam PR. Rapid assessment of mycobacterial growth inside macrophages and mice, using the radiometric (BACTEC) method. TUBERCLE AND LUNG DISEASE : THE OFFICIAL JOURNAL OF THE INTERNATIONAL UNION AGAINST TUBERCULOSIS AND LUNG DISEASE 1994; 75:127-31. [PMID: 8032045 DOI: 10.1016/0962-8479(94)90041-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
SETTING Conventional methods of determining the growth and drug susceptibility of mycobacteria either in macrophages or in vivo are time consuming and laborious. OBJECTIVE We sought to develop a simple and rapid method for assessing growth and susceptibility of mycobacteria in macrophages and in vivo. DESIGN The radiometric (BACTEC) method was compared with the conventional method for rapid assessment of growth and susceptibility of Mycobacterium avium complex (MAC) to clofazimine (CFM) and its two analogues (B4100 and B4101) in macrophages and in beige mice. RESULTS AND CONCLUSIONS A linear relationship was observed between growth index (GI) readings by the BACTEC method and the colony forming unit (CFU) counts obtained by conventional plating on 7H11 agar in vitro of lysates from infected macrophages and of homogenates from the infected organs. There was also a good agreement between the two methods with respect to susceptibility of MAC to CFM and its analogues both in macrophages and in spleen. The BACTEC method, in addition to being quick and simple, was found to be more consistent. Our studies thus demonstrate that the radiometric method has potential application in rapid screening of drugs for antimycobacterial activity in macrophages and in animals besides its established value in in vitro screening.
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Affiliation(s)
- M V Reddy
- Mycobacteriology Research Laboratories, University of Illinois College of Medicine, Chicago
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22
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Limb DI, Wheat PF, Spencer RC, Harris GS, Rayner AB, Watt B. Comparison of techniques for antimicrobial susceptibility testing of mycobacteria. J Clin Pathol 1993; 46:403-7. [PMID: 8320319 PMCID: PMC501246 DOI: 10.1136/jcp.46.5.403] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
AIMS To evaluate adenosine triphosphate (ATP) bioluminescence as a rapid technique for antimicrobial susceptibility testing of Mycobacterium spp by comparing it with conventional and radiometric methods, and to assess its potential for use in clinical microbiology laboratories. METHODS 115 clinical isolates from a wide range of mycobacterial species and four control organisms of known susceptibility were tested against six antimicrobial agents. Minimum inhibitory concentrations (MICs) were determined after 4-6 weeks' incubation on Middlebrook 7H10 agar. Susceptibility was also determined radiometrically using a Bactec 460, and by bioluminescent assay of ATP using a 1250 luminometer (LKB-Wallac). RESULTS Susceptibility results after 7 days showed excellent correlation with conventionally determined MICs. 714 susceptibility tests were performed by both techniques, with seven major discrepancies between the two systems. For pyrazinamide, agreement was 100%, but five strains of M tuberculosis, including one control, and 11 mycobacteria other than M tuberculosis (MOTT) failed to grow on Middlebrook agar at pH 5.5. 606 tests were performed by radiometry, with four major discrepancies between this technique and ATP bioluminescence. No particular species of Mycobacterium gave aberrant results. Contamination was a problem; 12 of the 119 strains tested were contaminated at day 1 and had to be repeated before results were obtained. Contamination of individual tests increased significantly after 7 days of incubation. CONCLUSIONS ATP bioluminescence can be used to monitor mycobacterial growth in fluid culture media; the technique has considerable potential for rapid susceptibility testing. Advantages include lower initial cost of analytical equipment, lower reagent cost per test, and the use of non-radioactive substrates.
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Affiliation(s)
- D I Limb
- Department of Bacteriology, Royal Hallamshire Hospital, Sheffield
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23
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Tomioka H, Saito H, Fujii K, Sato K, Hidaka T. In vitro antimicrobial activity of benzoxazinorifamycin, KRM-1648, against Mycobacterium avium complex, determined by the radiometric method. Antimicrob Agents Chemother 1993; 37:67-70. [PMID: 8431020 PMCID: PMC187606 DOI: 10.1128/aac.37.1.67] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
MICs of a newly developed benzoxazinorifamycin derivative, KRM-1648, for Mycobacterium avium complex (MAC) were determined by the BACTEC 460 TB system and compared with those of other known antimicrobial agents. The radiometric method gave a fast, accurate, and reproducible MIC for each antimicrobial agent. MICs of KRM-1648 for 30 strains of MAC (10 strains each of M. avium isolated from AIDS and non-AIDS patients and of Mycobacterium intracellulare isolated from non-AIDS patients) were measured. The MICs, ranging from 0.004 to 0.0625 microgram/ml, were the lowest of all tested drugs, including rifampin, rifabutin, streptomycin, kanamycin, isoniazid, ethambutol, ofloxacin, ciprofloxacin, sparfloxacin, and clarithromycin. The MICs were 2 to 512 and 1 to 32 times lower than those of rifampin and rifabutin, respectively. With rifampin and ethambutol, there were some differences between the MICs for M. avium isolated from AIDS patients (American) and those for M. avium from non-AIDS patients (Japanese). Moreover, appreciable differences between the MICs of some drugs against M. avium and M. intracellulare isolated from non-AIDS patients were found. Many strains of M. avium were more susceptible to ofloxacin than M. intracellulare, but, conversely, M. avium was more resistant to rifampin, streptomycin, ethambutol, and clarithromycin than M. intracellulare.
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Affiliation(s)
- H Tomioka
- Department of Microbiology and Immunology, Shimane Medical University, Japan
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24
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Piersimoni C, Morbiducci V, Bornigia S, De Sio G, Scalise G. In vitro activity of the new quinolone lomefloxacin against Mycobacterium tuberculosis. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1992; 146:1445-7. [PMID: 1333738 DOI: 10.1164/ajrccm/146.6.1445] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Minimal inhibitory concentrations (MIC) of ciprofloxacin, ofloxacin and lomefloxacin were determined for 90 Mycobacterium tuberculosis strains isolated from both AIDS and other patients. Eleven (12.2%) of these strains showed in vitro resistance to one or more first-line antituberculosis drugs. Susceptibility tests were done in 7H12 broth by the radiometric method. The MIC range for ciprofloxacin was 0.125 to 4.0 micrograms/ml; for ofloxacin, 0.25 to 4.0; and for lomefloxacin 0.5 to 4.0 micrograms/ml. On the basis of our data, we believe that the following MIC, when determined in 7H12 broth radiometrically, should be used as break points to classify the strain as susceptible: ciprofloxacin and ofloxacin, 1 microgram/ml or less; lomefloxacin, 2 micrograms/ml or less. Lomefloxacin on a once-daily basis deserves further evaluation as a potential supplementary drug for the treatment of tuberculosis.
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Affiliation(s)
- C Piersimoni
- Department of Clinical Microbiology, General Hospital Umberto I. Torrette, Ancona, Italy
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25
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Babinchak TJ, Fass RJ. In vitro activity of DNA gyrase inhibitors, singly and in combination, against Mycobacterium avium complex. Diagn Microbiol Infect Dis 1992; 15:367-70. [PMID: 1319302 DOI: 10.1016/0732-8893(92)90026-p] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The in vitro activities of the DNA gyrase inhibitors ciprofloxacin, coumermycin, and novobiocin against 31 clinical isolates of Mycobacterium avium complex were studied using a microdilution technique. Minimal inhibitory concentrations (MICs) were determined in 4 days using Middlebrook 7H9 broth, and minimal bactericidal concentrations (MBCs) were determined by subculturing to Middlebrook 7H10 agar. MICs were: ciprofloxacin, 0.5-greater than 16 (mean, 4.1) micrograms/ml; novobiocin, 4-greater than 128 (mean, 54.7) micrograms/ml; and coumermycin, 2-greater than 16 (mean, 17.5) micrograms/ml. MBCs were usually more than two dilution steps higher than MICs. Checkerboard studies failed to reveal synergistic or antagonistic inhibitory activity of DNA gyrase-A and DNA gyrase-B inhibitors in vitro.
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Affiliation(s)
- T J Babinchak
- Department of Internal Medicine, Ohio State University College of Medicine, Columbus
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26
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Gangadharam PR, Perumal VK, Farhi DC, LaBrecque J. The beige mouse model for Mycobacterium avium complex (MAC) disease: optimal conditions for the host and parasite. TUBERCLE 1989; 70:257-71. [PMID: 2626803 DOI: 10.1016/0041-3879(89)90020-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We extended our earlier studies to establish the beige (C57B1/6/bgJ/bgJ) mouse model for experimental acute infections with Mycobacterium avium complex (MAC). Optimal conditions of the host and the parasites have been determined. Mice bred at our center showed similar responses to those obtained from Jackson Laboratories, the original supplier. Both male and female mice showed similar responses, but older mice in both sexes showed less susceptibility than younger mice. Strain 101 of MAC showed remarkable consistency in its pathogenicity to beige mice, as evidenced by the distribution of colony forming unit (CFU) counts at various time points after intravenous challenge, in several experiments. CFU counts showed an association with the dose of challenge, and histopathological observations.
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Affiliation(s)
- P R Gangadharam
- Mycobacteriology Research Laboratories, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado
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27
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Chen CH, Shih JF, Lindholm-Levy PJ, Heifets LB. Minimal inhibitory concentrations of rifabutin, ciprofloxacin, and ofloxacin against Mycobacterium tuberculosis isolated before treatment of patients in Taiwan. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1989; 140:987-9. [PMID: 2552883 DOI: 10.1164/ajrccm/140.4.987] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Minimal inhibitory concentrations (MICs) of rifabutin, ciprofloxacin, and ofloxacin were determined for "wild" Mycobacterium tuberculosis strains, susceptible to all antituberculosis drugs in the conventional test, isolated from newly diagnosed Taiwanese patients who had never had prior treatment for tuberculosis. These MICs were within the limits previously reported for strains isolated in the United States. The range of MICs of rifabutin for Taiwanese strains was 0.015 to 0.125 micrograms/ml; ciprofloxacin, 0.25 to 2.0 micrograms/ml; ofloxacin, 0.5 to 2.0 micrograms/ml. On the basis of an evaluation of the highest broth-determined MICs found in this and in a previous study, we suggest that the following MICs, when determined in 7H12 broth radiometrically, should be used as breakpoints to classify the strain as "susceptible": for rifabutin, 0.125 micrograms/ml or less; for ofloxacin and ciprofloxacin, 2.0 micrograms/ml or less.
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Affiliation(s)
- C H Chen
- Department of Chest Medicine, Veterans General Hospital, Taipei, Taiwan, Republic of China
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28
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Burnens AP, Vurma-Rapp U. Simplified diagnostic susceptibility testing of mycobacteria against thiacetazone, hydroxylamine, p-nitrobenzoic acid and picric acid. Res Microbiol 1989; 140:235-41. [PMID: 2482520 DOI: 10.1016/0923-2508(89)90078-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In order to simplify diagnostic susceptibility testing of mycobacteria against thiacetazone, hydroxylamine, p-nitrobenzoic acid and picric acid, we modified the standard procedure by using Middlebrook 7H11 agar in a single quadrant petri dish. This plate can be inoculated and read in parallel with routine susceptibility tests done by the proportion method. We present results of 449 consecutive routine strains tested with our method.
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Affiliation(s)
- A P Burnens
- Institute for Veterinary Bacteriology, University of Berne, Switzerland
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29
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Suo J, Chang CE, Lin TP, Heifets LB. Minimal inhibitory concentrations of isoniazid, rifampin, ethambutol, and streptomycin against Mycobacterium tuberculosis strains isolated before treatment of patients in Taiwan. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1988; 138:999-1001. [PMID: 3144210 DOI: 10.1164/ajrccm/138.4.999] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Minimal inhibitory concentrations (MICs) of isoniazid (INH), rifampin (RMP), ethambutol (EMB), and streptomycin (SM) for susceptible "wild" M. tuberculosis strains isolated from Taiwanese patients were within the limits previously reported for strains isolated in the United States. The highest agar-determined MICs (in 7H10 and 7H11 agar) corresponded well with the critical concentrations established for these media. The highest MICs found radiometrically in 7H12 broth were significantly lower than the critical concentrations proposed for this medium. On the basis of an evaluation of the highest broth-determined MICs found in this and in the previous study (1), we suggest that the following MICs, when determined radiometrically, should be used as breakpoints to classify the strain as "susceptible": for INH, 0.1 microgram/ml or less; for RMP, 0.5 microgram/ml or less; for EMB, 4.0 micrograms/ml or less; for SM, 2.0 micrograms/ml or less.
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Affiliation(s)
- J Suo
- Taiwan Provincial Tuberculosis Control Bureau, Taipei, Republic of China
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30
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Modified inoculum for radiometric susceptibility testing ofMycobacterium tuberculosis. Curr Microbiol 1988. [DOI: 10.1007/bf01571322] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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31
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Lindholm-Levy PJ, Heifets LB. Clofazimine and other rimino-compounds: minimal inhibitory and minimal bactericidal concentrations at different pHs for Mycobacterium avium complex. TUBERCLE 1988; 69:179-86. [PMID: 3254636 DOI: 10.1016/0041-3879(88)90019-0] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Clofazimine (Lamprene, B663) and 11 rimino-compounds were tested for activity against Mycobacterium avium by finding the minimal inhibitory concentrations (MIC) of these drugs in liquid medium. The activity of these compounds was affected in acidic conditions (pH 6.0 and 5.0), but the MICs observed even at pH 5.0 were significantly lower than the concentrations achievable in macrophages. This information is especially useful in the light of four important facts: that these drugs tend to accumulate within macrophages; that M. avium tends to multiply within macrophages; that this intracellular environment has a low pH; and that M. avium tolerates these low pH conditions. Such data confirm the expectation that rimino-compounds inhibit the intracellular M. avium bacterial population. The minimal bactericidal concentrations (MBC) of clofazimine and B746, the most active analogue, were from 64 to 256 times higher than the MIC, but it is not clear whether these drugs can accumulate within the macrophages in concentrations high enough to produce the bactericidal effect as well.
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Affiliation(s)
- P J Lindholm-Levy
- National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
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32
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Heifets L. MIC as a quantitative measurement of the susceptibility of Mycobacterium avium strains to seven antituberculosis drugs. Antimicrob Agents Chemother 1988; 32:1131-6. [PMID: 2461162 PMCID: PMC172364 DOI: 10.1128/aac.32.8.1131] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
MICs of isoniazid, rifampin, ethionamide, streptomycin, amikacin, kanamycin, and capreomycin were determined for Mycobacterium avium complex strains by two methods: broth dilution in 7H12 medium radiometrically and agar dilution on 7H10 agar plates. The broth-determined MICs of all drugs with the exception of isoniazid were two to eight times lower than the agar-determined MICs for most of the tested M. avium strains, which is probably due to the higher absorption and degradation of the drugs in solid media. The MICs, especially those determined in broth, are suggested as quantitative measurements of the degree of susceptibility of M. avium complex strains. For a certain percentage of the M. avium strains the broth-determined MICs were within the limits of MICs found for wild susceptible Mycobacterium tuberculosis strains. These M. avium strains were classified as presumably susceptible. In contrast to M. tuberculosis, the MICs for M. avium strains had a wide range. When the MICs for M. avium strains were only one dilution higher than those for M. tuberculosis, they were tentatively classified as moderately susceptible. The designation moderately resistant or resistant, respectively, is suggested for those M. avium strains for which the MICs were at or above the concentrations achievable in blood. The quantitation of the degree of susceptibility by the MICs and the tentative interpretation of the MICs are suggested for future use in clinical trials as a means of evaluating the patients' responses to chemotherapy compared with the degree of susceptibility of the initial strain isolated before treatment.
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Affiliation(s)
- L Heifets
- National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206
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Heifets LB, Iseman MD, Lindholm-Levy PJ. Combinations of rifampin or rifabutine plus ethambutol against Mycobacterium avium complex. Bactericidal synergistic, and bacteriostatic additive or synergistic effects. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1988; 137:711-5. [PMID: 2830814 DOI: 10.1164/ajrccm/137.3.711] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Ethambutol, when combined with rifampin or rifabutine (ansamycin, LM427), produced an additive inhibitory effect against most of the tested M avium complex strains (12 of 16 with rifampin, 13 of 16 with rifabutine). The inhibitory effect was synergistic for the remaining 4 of 16 and 3 of 16 strains. This relationship reduced the minimal inhibitory concentrations for each drug in combination. In addition, the minimal bactericidal concentrations of all 3 drugs were reduced because of synergistic bactericidal activity in 6 of 6 strains tested.
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Affiliation(s)
- L B Heifets
- National Jewish Center for Immunology and Respiratory Medicine, Denver, CO 80206
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Woodley CL, Smithwick RW. Radiometric method for pyrazinamide susceptibility testing of Mycobacterium tuberculosis in egg-yolk-enriched BACTEC 12A medium. Antimicrob Agents Chemother 1988; 32:125-7. [PMID: 3126704 PMCID: PMC172111 DOI: 10.1128/aac.32.1.125] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
A radiometric method for testing the susceptibility of Mycobacterium tuberculosis to pyrazinamide in egg-yolk-enriched 12A medium (pH 5.5) is described. We obtained 100% agreement between the 7H10 agar method with 25 microgram of pyrazinamide per ml and the modified radiometric method with a drug concentration of 50 microgram/ml in tests of 90 clinical isolates.
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Affiliation(s)
- C L Woodley
- Division of Bacterial Diseases, Centers for Disease Control, Atlanta, Georgia 30333
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35
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Wallace RJ, Nash DR, Steele LC, Steingrube V. Susceptibility testing of slowly growing mycobacteria by a microdilution MIC method with 7H9 broth. J Clin Microbiol 1986; 24:976-81. [PMID: 3097069 PMCID: PMC269082 DOI: 10.1128/jcm.24.6.976-981.1986] [Citation(s) in RCA: 151] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Based on previous success with rapidly growing mycobacteria, a microdilution MIC system was devised for slowly growing mycobacterial species using 7H9 broth. Test drugs included isoniazid, rifampin, ethambutol, streptomycin, clofazamine, and sulfamethoxazole. Sixty isolates of four mycobacterial species, including Mycobacterium tuberculosis, from patients who had never received drug therapy were evaluated in the system, as well as 25 drug-resistant isolates and 11 control strains. MICs were read when good macroscopic control growth was evident, a period which varied with each species. Most species exhibited a narrow range of MICs with easily discernible growth endpoints. The aminoglycosides, ethambutol, clofazamine, and sulfamethoxazole were the only drugs with activity against all species at clinically achievable levels in serum. Correlation between susceptibilities by the proportion method in agar with single drug concentrations and the broth method were excellent for M. tuberculosis, M. kansasii, and M. marinum for isoniazid, rifampin, and ethambutol. Isolates of the M. avium complex were much more susceptible in broth than in agar for rifampin, ethambutol, and streptomycin. Given the successful transition of most microbiology laboratories to MIC plates for other bacterial species, this method would allow for testing of multiple drugs at multiple concentrations and has good potential for evaluation of drug combinations and drug-resistant isolates.
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Heifets LB, Iseman MD, Lindholm-Levy PJ. Ethambutol MICs and MBCs for Mycobacterium avium complex and Mycobacterium tuberculosis. Antimicrob Agents Chemother 1986; 30:927-32. [PMID: 3101588 PMCID: PMC180621 DOI: 10.1128/aac.30.6.927] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We determined the MICs of ethambutol for both Mycobacterium avium and Mycobacterium tuberculosis strains by using broth dilution (7H12 broth, radiometric method) and agar dilution (7H11 agar) methods. We found the MICs to be much lower in liquid than in solid medium. The broth-determined MICs for susceptible M. tuberculosis and most of the M. avium strains were comparable to the levels in blood of patients, being lower than the peak levels. We propose that the MICs, determined radiometrically in in 7H12 broth, be considered as tentative criteria for susceptibility testing of M. avium isolates in future clinical trials. The use of these values instead of critical concentrations should also be considered as an alternative to the conventional susceptibility testing method in chemotherapy of tuberculosis. Ethambutol produced bactericidal effects against both M. tuberculosis and M. avium, and the MIC/MBC ratios were in the same range for both species when MICs and MBCs were tested in 7H12 broth by conventional sampling and plating.
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Heifets LB, Iseman MD, Lindholm-Levy PJ, Kanes W. Determination of ansamycin MICs for Mycobacterium avium complex in liquid medium by radiometric and conventional methods. Antimicrob Agents Chemother 1985; 28:570-5. [PMID: 4073881 PMCID: PMC180307 DOI: 10.1128/aac.28.4.570] [Citation(s) in RCA: 66] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
A radiometric method to determine the MIC of ansamycin (LM427) for Mycobacterium avium complex clinical isolates has been developed. It is based on a comparison of the conventional growth curve determination and the radiometric detection of growth (growth index) in the same liquid medium (7H12 broth). This new method requires less time and labor than does a conventional determination of MIC in liquid medium (CFU). Other advantages of this method include relatively short periods of exposure of the drug to 37 degrees C and the composition of 7H12 broth, which has practically no substrates which could absorb or bind the drug. Thus, a more accurate estimation of the MIC in this medium can be expected than by the conventional agar dilution (proportion) method. The MICs of ansamycin appeared to be higher in agar plates than in 7H12 broth. More than 70% of the isolates had a broth-determined MIC one to three times lower than the average peak concentration of ansamycin achieved in sera of patients. The wide range of MICs suggests the importance of testing susceptibility in broth with many concentrations in addition to, or rather than in, agar plates with concentrations of 2.0 or 1.0 micrograms/ml only. Taking into account relatively low levels of ansamycin in sera of patients, it would be appropriate to compare the MICs with the levels in serum to make the outcome of chemotherapy more predictable.
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