1
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Epidemiological cut-off values for a 96-well broth microdilution plate for high-throughput research antibiotic susceptibility testing of M. tuberculosis. Eur Respir J 2022; 60:2200239. [PMID: 35301246 PMCID: PMC9556810 DOI: 10.1183/13993003.00239-2022] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 02/22/2022] [Indexed: 12/15/2022]
Abstract
Drug susceptibility testing of M. tuberculosis is rooted in a binary susceptible/resistant paradigm. While there are considerable advantages in measuring the minimum inhibitory concentrations (MICs) of a panel of drugs for an isolate, it is necessary to measure the epidemiological cut-off values (ECOFF/ECVs) to permit comparison with qualitative data. Here we present ECOFF/ECVs for 13 anti-tuberculosis compounds, including bedaquiline and delamanid, derived from 20 637 clinical isolates collected by 14 laboratories based in 11 countries on five continents. Each isolate was incubated for 14 days on a dry 96-well broth microdilution plate and then read. Resistance to most of the drugs due to prior exposure is expected and the MIC distributions for many of the compounds are complex, and therefore a phenotypically wild-type population could not be defined. Since a majority of samples also underwent genetic sequencing, we defined a genotypically wild-type population and measured the MIC of the 99th percentile by direct measurement and via fitting a Gaussian using interval regression. The proposed ECOFF/ECVs were then validated by comparing with the MIC distributions of high-confidence genetic variants that confer resistance and with qualitative drug susceptibility tests obtained via the Mycobacterial Growth Indicator Tube (MGIT) system or Microscopic-Observation Drug Susceptibility (MODS) assay. These ECOFF/ECVs will inform and encourage the more widespread adoption of broth microdilution: this is a cheap culture-based method that tests the susceptibility of 12-14 antibiotics on a single 96-well plate and so could help personalise the treatment of tuberculosis.
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Affiliation(s)
- The CRyPTIC Consortium
- For a list of all members of the CRyPTIC Consortium and their affiliations, please see the section at the end of this article
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2
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Tang Q, Ke H, Sun WW, Zhang SJ, Fan L. The Correlations of Minimal Inhibitory Concentration Values of Anti-TB Drugs with Treatment Outcomes and Clinical Profiles in Patients with Multidrug-Resistant Tuberculosis (MDR-TB) in China. Infect Drug Resist 2022; 15:5275-5287. [PMID: 36106053 PMCID: PMC9464630 DOI: 10.2147/idr.s374687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 08/20/2022] [Indexed: 11/23/2022] Open
Abstract
Objective It is a challenge to obtain satisfactory treatment outcomes for patients with multidrug-resistant/rifampicin-resistant tuberculosis (MDR/RR-TB); the study aims to correlate the Minimum Inhibitory Concentration (MIC) value of drugs with the outcome of patients with MDR/RR-TB to obtain an understanding for better regimens and optimal outcomes. Methods The patients diagnosed with MDR/RR-TB were retrospectively enrolled from January 1, 2018 to December 31, 2019, recorded clinical characteristics, MIC DST (Drug Susceptibility Test) results, and followed the treatment outcome. The data were analyzed on the correlations of MIC DST values with outcomes and clinical characteristics. Results A total of 276 patients with MDR/RR-TB were included, containing 98 cases (35.5%) with newly treated patients and 178 cases (64.5%) with re-treated patients. A total of 220 cases recorded treatment success (79.7%) and 49 cases recorded treatment failure or died. MIC values of isoniazid (H), moxifloxacin (Mfx), and ethionamide (Eto) in newly treated patients were lower than those in retreated patients, and resistance levels of Mfx and H were closely associated with the treatment outcome (P < 0.05) while those of other drugs had no close association with treatment outcome. Conclusions MIC values of some anti-TB drugs, such as fluoroquinolones (FQs) and H, can reflect the treatment outcome for patients with MDR/RR-TB, which can contribute to making regimens for better treatment outcomes.
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Affiliation(s)
- Qin Tang
- Department of Tuberculosis, Shanghai Clinical Research Center for Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai, 200433, People's Republic of China
| | - Hui Ke
- Department of Tuberculosis, Shanghai Clinical Research Center for Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai, 200433, People's Republic of China
| | - Wen-Wen Sun
- Department of Tuberculosis, Shanghai Clinical Research Center for Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai, 200433, People's Republic of China
| | - Shao-Jun Zhang
- Department of Tuberculosis, Shanghai Clinical Research Center for Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai, 200433, People's Republic of China
| | - Lin Fan
- Department of Tuberculosis, Shanghai Clinical Research Center for Tuberculosis, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai Clinical Research Center for Tuberculosis, Shanghai Key Laboratory of Tuberculosis, Shanghai, 200433, People's Republic of China
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3
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Chung ES, Johnson WC, Aldridge BB. Types and functions of heterogeneity in mycobacteria. Nat Rev Microbiol 2022; 20:529-541. [PMID: 35365812 DOI: 10.1038/s41579-022-00721-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2022] [Indexed: 12/24/2022]
Abstract
The remarkable ability of Mycobacterium tuberculosis to survive attacks from the host immune response and drug treatment is due to the resilience of a few bacilli rather than a result of survival of the entire population. Maintenance of mycobacterial subpopulations with distinct phenotypic characteristics is key for survival in the face of dynamic and variable stressors encountered during infection. Mycobacterial populations develop a wide range of phenotypes through an innate asymmetric growth pattern and adaptation to fluctuating microenvironments during infection that point to heterogeneity being a vital survival strategy. In this Review, we describe different types of mycobacterial heterogeneity and discuss how heterogeneity is generated and regulated in response to environmental cues. We discuss how this heterogeneity may have a key role in recording memory of their environment at both the single-cell level and the population level to give mycobacterial populations plasticity to withstand complex stressors.
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Affiliation(s)
- Eun Seon Chung
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA
| | - William C Johnson
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA.,Tufts University School of Graduate Biomedical Sciences, Boston, MA, USA
| | - Bree B Aldridge
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, MA, USA. .,Tufts University School of Graduate Biomedical Sciences, Boston, MA, USA. .,Stuart B. Levy Center for Integrated Management of Antimicrobial Resistance, Tufts University, Boston, MA, USA. .,Department of Biomedical Engineering, Tufts University School of Engineering, Medford, MA, USA.
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4
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Prabhu P, Fernandes T, Damani M, Chaubey P, Narayanan S, Sawarkar S. 2Receptor Specific Ligand conjugated Nanocarriers: an Effective Strategy for Targeted Therapy of Tuberculosis. Curr Drug Deliv 2021; 19:830-845. [PMID: 34915835 DOI: 10.2174/1567201819666211216141942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 08/09/2021] [Accepted: 10/27/2021] [Indexed: 11/22/2022]
Abstract
Tuberculosis (TB) is an ancient chronic disease caused by the bacillus Mycobacterium tuberculosis, which has affected mankind for more than 4,000 years. Compliance with the standard conventional treatment can assure recovery from tuberculosis, but emergence of drug resistant strains pose a great challenge for effective management of tuberculosis. The process of discovery and development of new therapeutic entities with better specificity and efficacy is unpredictable and time consuming. Hence, delivery of pre-existing drugs with improved targetability is the need of the hour. Enhanced delivery and targetability can ascertain improved bioavailability, reduced toxicity, decreased frequency of dosing and therefore better patient compliance. Nanoformulations are being explored for effective delivery of therapeutic agents, however optimum specificity is not guaranteed. In order to achieve specificity, ligands specific to receptors or cellular components of macrophage and Mycobacteria can be conjugatedto nanocarriers. This approach can improve localization of existing drug molecules at the intramacrophageal site where the parasites reside, improve targeting to the unique cell wall structure of Mycobacterium or improve adhesion to epithelial surface of intestine or alveolar tissue (lectins). Present review focuses on the investigation of various ligands like Mannose, Mycolic acid, Lectin, Aptamers etc. installed nanocarriers that are being envisaged for targeting antitubercular drugs.
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Affiliation(s)
- Pratiksha Prabhu
- Department of Pharmaceutics, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, University of Mumbai. Saudi Arabia
| | - Trinette Fernandes
- Department of Pharmaceutics, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, University of Mumbai. Saudi Arabia
| | - Mansi Damani
- Department of Pharmaceutics, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, University of Mumbai. Saudi Arabia
| | - Pramila Chaubey
- Department of Pharmaceutics, College of Pharmacy, Shaqra University, Al-Dawadmi. Saudi Arabia
| | - Shridhar Narayanan
- Foundation for Neglected Disease Research, 20A, KIADB Industrial Area Veerapura, Doddaballapur, Bengaluru, Karnataka 561203. India
| | - Sujata Sawarkar
- Department of Pharmaceutics, SVKM's Dr. Bhanuben Nanavati College of Pharmacy, University of Mumbai. Saudi Arabia
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5
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Ernest JP, Sarathy J, Wang N, Kaya F, Zimmerman MD, Strydom N, Wang H, Xie M, Gengenbacher M, Via LE, Barry CE, Carter CL, Savic RM, Dartois V. Lesion Penetration and Activity Limit the Utility of Second-Line Injectable Agents in Pulmonary Tuberculosis. Antimicrob Agents Chemother 2021; 65:e0050621. [PMID: 34252307 PMCID: PMC8448094 DOI: 10.1128/aac.00506-21] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/08/2021] [Indexed: 11/20/2022] Open
Abstract
Amikacin and kanamycin are second-line injectables used in the treatment of multidrug-resistant tuberculosis (MDR-TB) based on the clinical utility of streptomycin, another aminoglycoside and first-line anti-TB drug. While streptomycin was tested as a single agent in the first controlled TB clinical trial, introduction of amikacin and kanamycin into MDR-TB regimens was not preceded by randomized controlled trials. A recent large retrospective meta-analysis revealed that compared with regimens without any injectable drug, amikacin provided modest benefits, and kanamycin was associated with worse outcomes. Although their long-term use can cause irreversible ototoxicity, they remain part of MDR-TB regimens because they have a role in preventing emergence of resistance to other drugs. To quantify the contribution of amikacin and kanamycin to second-line regimens, we applied two-dimensional matrix-assisted laser desorption ionization (MALDI) mass spectrometry imaging in large lung lesions, quantified drug exposure in lung and in lesions of rabbits with active TB, and measured the concentrations required to kill or inhibit growth of the resident bacterial populations. Using these metrics, we applied site-of-action pharmacokinetic and pharmacodynamic (PK-PD) concepts and simulated drug coverage in patients' lung lesions. The results provide a pharmacological explanation for the limited clinical utility of both agents and reveal better PK-PD lesion coverage for amikacin than kanamycin, consistent with retrospective data of contribution to treatment success. Together with recent mechanistic studies dissecting antibacterial activity from aminoglycoside ototoxicity, the limited but rapid penetration of streptomycin, amikacin, and kanamycin to the sites of TB disease supports the development of analogs with improved efficacy and tolerability.
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Affiliation(s)
- Jacqueline P. Ernest
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Jansy Sarathy
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Ning Wang
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Firat Kaya
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Matthew D. Zimmerman
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Natasha Strydom
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Han Wang
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Min Xie
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Martin Gengenbacher
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
- Hackensack School of Medicine, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Laura E. Via
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, Maryland, USA
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
| | - Clifton E. Barry
- Tuberculosis Research Section, Laboratory of Clinical Immunology and Microbiology, NIAID, NIH, Bethesda, Maryland, USA
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
| | - Claire L. Carter
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
| | - Radojka M. Savic
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California, USA
| | - Véronique Dartois
- Center for Discovery and Innovation, Hackensack Meridian Health, Nutley, New Jersey, USA
- Hackensack School of Medicine, Hackensack Meridian Health, Nutley, New Jersey, USA
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6
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Jain NK. WHO consolidated guidelines on tuberculosis 2020 moving toward fully oral regimen: Should country act in hurry? Lung India 2021; 38:303-306. [PMID: 34259166 PMCID: PMC8272430 DOI: 10.4103/lungindia.lungindia_982_20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/25/2021] [Indexed: 11/17/2022] Open
Affiliation(s)
- Nirmal Kumar Jain
- Department of Respiratory Medicine, JNU Medical College, Jaipur, Rajasthan, India
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7
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Affiliation(s)
| | - Tom Decroo
- Institute of Tropical Medicine, Unit of HIV and TB, Department of Clinical Sciences, Antwerp, Belgium.,Research Foundation Flanders, Brussels, Belgium
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8
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Atypical Genetic Basis of Pyrazinamide Resistance in Monoresistant Mycobacterium tuberculosis. Antimicrob Agents Chemother 2021; 65:AAC.01916-20. [PMID: 33722890 PMCID: PMC8315952 DOI: 10.1128/aac.01916-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 03/02/2021] [Indexed: 02/07/2023] Open
Abstract
Pyrazinamide (PZA) is a widely used antitubercular chemotherapeutic. Typically, PZA resistance (PZA-R) emerges in Mycobacterium tuberculosis strains with existing resistance to isoniazid and rifampin (i.e., multidrug resistance [MDR]) and is conferred by loss-of-function pncA mutations that inhibit conversion to its active form, pyrazinoic acid (POA). PZA-R departing from this canonical scenario is poorly understood. Here, we genotyped pncA and purported alternative PZA-R genes (panD, rpsA, and clpC1) with long-read sequencing of 19 phenotypically PZA-monoresistant isolates collected in Sweden and compared their phylogenetic and genomic characteristics to a large set of MDR PZA-R (MDRPZA-R) isolates. We report the first association of ClpC1 mutations with PZA-R in clinical isolates, in the ClpC1 promoter (clpC1p−138) and the N terminus of ClpC1 (ClpC1Val63Ala). Mutations have emerged in both these regions under POA selection in vitro, and the N-terminal region of ClpC1 has been implicated further, through its POA-dependent efficacy in PanD proteolysis. ClpC1Val63Ala mutants spanned 4 Indo-Oceanic sublineages. Indo-Oceanic isolates invariably harbored ClpC1Val63Ala and were starkly overrepresented (odds ratio [OR] = 22.2, P < 0.00001) among PZA-monoresistant isolates (11/19) compared to MDRPZA-R isolates (5/80). The genetic basis of Indo-Oceanic isolates’ overrepresentation in PZA-monoresistant tuberculosis (TB) remains undetermined, but substantial circumstantial evidence suggests that ClpC1Val63Ala confers low-level PZA resistance. Our findings highlight ClpC1 as potentially clinically relevant for PZA-R and reinforce the importance of genetic background in the trajectory of resistance development.
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9
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Tahseen S, Van Deun A, de Jong BC, Decroo T. Second-line injectable drugs for rifampicin-resistant tuberculosis: better the devil we know? J Antimicrob Chemother 2020; 76:831-835. [DOI: 10.1093/jac/dkaa489] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
In its 2020 guidelines for the treatment of rifampicin-resistant TB (RR-TB), the WHO recommends all-oral fluoroquinolone-based regimens, with bedaquiline replacing the second-line injectable drugs (SLIDs). SLIDs were used for their strong acquired resistance-preventing activity. Data from three cohorts showed acquired bedaquiline resistance ranging between 2.5% and 30.8%, with no protection from a SLID in most cases. If bedaquiline resistance is that easily acquired, it will fail to protect fluoroquinolones and other drugs from acquiring resistance. Until evidence on resistance-preventing activity shows that SLIDs can safely be replaced, we call for more prudent use of the few potent second-line TB drugs available. Studies on new treatment regimens need to prioritize the prevention of acquired resistance along with treatment success. Meanwhile, reducing the dosing of SLIDs to thrice weekly from Day 1, and their replacement for any degree of audiometry abnormalities before or during treatment will largely avoid serious ototoxicity.
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Affiliation(s)
- Sabira Tahseen
- National TB Reference laboratory, National TB Control Program, Islamabad, Pakistan
| | | | - Bouke C de Jong
- Institute of Tropical Medicine, Unit of Mycobacteriology, Department of Biomedical Sciences, 2000, Antwerp, Belgium
| | - Tom Decroo
- Institute of Tropical Medicine, Unit of HIV and TB, Department of Clinical Sciences, 2000, Antwerp, Belgium
- Research Foundation Flanders, 1000 Brussels, Belgium
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10
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Evidence for Expanding the Role of Streptomycin in the Management of Drug-Resistant Mycobacterium tuberculosis. Antimicrob Agents Chemother 2020; 64:AAC.00860-20. [PMID: 32540971 DOI: 10.1128/aac.00860-20] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/06/2020] [Indexed: 01/09/2023] Open
Abstract
In 2019, the WHO tuberculosis (TB) treatment guidelines were updated to recommend only limited use of streptomycin, in favor of newer agents or amikacin as the preferred aminoglycoside for drug-resistant Mycobacterium tuberculosis However, the emergence of resistance to newer drugs, such as bedaquiline, has prompted a reanalysis of antitubercular drugs in search of untapped potential. Using 211 clinical isolates of M. tuberculosis from South Africa, we performed phenotypic drug susceptibility testing (DST) to aminoglycosides by both critical concentration and MIC determination in parallel with whole-genome sequencing to identify known genotypic resistance elements. Isolates with low-level streptomycin resistance mediated by gidB were frequently misclassified with respect to streptomycin resistance when using the WHO-recommended critical concentration of 2 μg/ml. We identified 29 M. tuberculosis isolates from South Africa with low-level streptomycin resistance concomitant with high-level amikacin resistance, conferred by gidB and rrs 1400, respectively. Using a large global data set of M. tuberculosis genomes, we observed 95 examples of this corresponding resistance genotype (gidB-rrs 1400), including identification in 81/257 (31.5%) of extensively drug resistant (XDR) isolates. In a phylogenetic analysis, we observed repeated evolution of low-level streptomycin and high-level amikacin resistance in multiple countries. Our findings suggest that current critical concentration methods and the design of molecular diagnostics need to be revisited to provide more accurate assessments of streptomycin resistance for gidB-containing isolates. For patients harboring isolates of M. tuberculosis with high-level amikacin resistance conferred by rrs 1400, and for whom newer agents are not available, treatment with streptomycin may still prove useful, even in the face of low-level resistance conferred by gidB.
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11
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Dusthackeer A, Saadhali SA, Thangam M, Hassan S, Balasubramanian M, Balasubramanian A, Ramachandran G, Kumar AKH, Thiruvenkadam K, Shanmugam G, Nirmal CR, Rajadas SE, Mohanvel SK, Mondal R. Wild-Type MIC Distribution for Re-evaluating the Critical Concentration of Anti-TB Drugs and Pharmacodynamics Among Tuberculosis Patients From South India. Front Microbiol 2020; 11:1182. [PMID: 32695072 PMCID: PMC7338667 DOI: 10.3389/fmicb.2020.01182] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 05/08/2020] [Indexed: 11/13/2022] Open
Abstract
The World Health Organization (WHO) has developed specific guidelines for critical concentrations (CCs) of antibiotics used for tuberculosis (TB) treatment, which is universally followed for drug susceptibility testing (DST) of clinical specimens. However, the CC of drugs can differ significantly among the mycobacterial species based on the population, geographic location, and the prevalence of the infecting strain in a particular area. The association between CC and the minimal inhibitory concentration (MIC) of anti-TB drugs is poorly understood. In this study, we assessed the MICs of anti-TB drugs, including isoniazid (INH), rifampicin (RMP), moxifloxacin (MXF), ethambutol (ETH), and p-aminosalicylic acid (PAS) on drug-sensitive Mtb isolates from pulmonary TB patients in South India. The MIC assays performed using solid- and liquid-growth media showed changes in the CC of a few of the tested antibiotics compared with the WHO-recommended levels. Our observation suggests that the WHO guidelines could potentially lead to overdiagnosis of drug-resistant cases, which can result in inappropriate therapeutic decisions. To evaluate the correlation between drug-resistance and CC, we performed the whole-genome sequencing for 16 mycobacterial isolates, including two wild-type and 14 resistant isolates. Our results showed that two of the isolates belonged to the W-Beijing lineage, while the rest were of the East-African-Indian type. We identified a total of 74 mutations, including five novel mutations, which are known to be associated with resistance to anti-TB drugs in these isolates. In our previous study, we determined the serum levels of INH and RMP among the same patients recruited in the current study and estimated the MICs of the corresponding infected isolates in these cases. Using these data and the CCs for INH and RMP from the present study, we performed pharmacodynamics (PD) evaluation. The results show that the PD of RMP was subtherapeutic. Together, these observations emphasize the need for optimizing the drug dosage based on the PD of large-scale studies conducted in different geographical settings.
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Affiliation(s)
- Azger Dusthackeer
- Department of Bacteriology, National Institute for Research in Tuberculosis, Chennai, India
| | - Shainaba A Saadhali
- Department of Bacteriology, National Institute for Research in Tuberculosis, Chennai, India
| | | | - Sameer Hassan
- Division of Neurogeriatrics, Karolinska Institutet, Solna, Sweden
| | | | | | - Geetha Ramachandran
- Department of Biochemistry, National Institute for Research in Tuberculosis, Chennai, India
| | - A K Hemanth Kumar
- Department of Biochemistry, National Institute for Research in Tuberculosis, Chennai, India
| | - Kannan Thiruvenkadam
- Department of Epidemiology, National Institute for Research in Tuberculosis, Chennai, India
| | - Govindarajan Shanmugam
- Department of Bacteriology, National Institute for Research in Tuberculosis, Chennai, India
| | | | - Sam Ebenezer Rajadas
- Department of Bacteriology, National Institute for Research in Tuberculosis, Chennai, India
| | | | - Rajesh Mondal
- Department of Bacteriology, National Institute for Research in Tuberculosis, Chennai, India
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12
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Epidemiological cut-offs for Sensititre susceptibility testing of Mycobacterium tuberculosis: interpretive criteria cross validated with whole genome sequencing. Sci Rep 2020; 10:1013. [PMID: 31974497 PMCID: PMC6978314 DOI: 10.1038/s41598-020-57992-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 01/08/2020] [Indexed: 11/20/2022] Open
Abstract
Universal drug susceptibility testing (DST) is an important requirement of the End TB Strategy. The Sensititre broth micro-dilution assay (BMD) tests multiple drugs quantitatively. We defined interpretive criteria for this assay and analysed genotypic-phenotypic relationships. 385 Mycobacterium tuberculosis clinical isolates were processed for BMD and whole genome sequencing. The epidemiological cut-off value 99% (ECV99) amongst genotypically wild type (gWT) strains defined susceptibility. Minimum inhibitory concentration distributions of the resistance-associated variants (RAVs) for each drug were analysed. Susceptibility (µg/mL) criteria were determined as follows: rifampicin (≤0.125), isoniazid (≤0.25), ethambutol (≤2.0), moxifloxacin (≤0.5), levofloxacin (≤1.0), amikacin (≤2.0), kanamycin (≤8.0), capreomycin (≤4.0), clofazimine (≤0.25) and linezolid (≤2.0). Most drugs showed clear separation between gWT and RAV. Isoniazid showed a tri-modal pattern with 14/17 strains at ECV99 harbouring a fabG1 c. -15C > T RAV. Ethambutol RAVs at embB codons 306, 405 and 497 were responsible for resistance and showed differential distributions. Moxifloxacin RAVs (gyrA codon 90) were a dilution or two higher than the ECV99 while gyrB RAVs were uncommon and showed drug specific resistance propensity. Interpretive criteria established were robust facilitating progress towards universal DST and individualised precision medicine. This study demonstrates the value of quantitative DST to accurately interpret mutation data.
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13
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Trébucq A, Decroo T, Van Deun A, Piubello A, Chiang CY, Koura KG, Schwoebel V. Short-Course Regimen for Multidrug-Resistant Tuberculosis: A Decade of Evidence. J Clin Med 2019; 9:E55. [PMID: 31881691 PMCID: PMC7019808 DOI: 10.3390/jcm9010055] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/11/2019] [Accepted: 12/13/2019] [Indexed: 02/06/2023] Open
Abstract
About ten years ago, the first results of the so-called "Bangladesh regimen", a short regimen lasting nine months instead of 20 months, revolutionized multidrug-resistant tuberculosis (MDR-TB) treatment. Similar short regimens were studied in different settings, relying for their efficacy on a later generation fluoroquinolone, either gatifloxacin, moxifloxacin, or levofloxacin. We review the published material on short MDR-TB regimens, describe their different compositions, their results in national tuberculosis programs in middle- and low-income countries, the risk of acquiring resistance to fluoroquinolone, and the occurrence of adverse events. With over 80% success, the regimen performs much better than longer regimens (usually around 50%). Monitoring of adverse events allows adapting its composition to prevent severe adverse events such as deafness. We discuss the current applicability and usefulness of the short injectable-containing regimen given the 2019 recommendation of the World Health Organization (WHO) for a new long all-oral regimen. We conclude that the most effective fluoroquinolone is gatifloxacin, currently not listed as an essential medicine by WHO. It is a priority to restore its status as an essential medicine.
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Affiliation(s)
- Arnaud Trébucq
- International Union Against Tuberculosis and Lung Disease, 75006 Paris, France; (A.P.); (C.-Y.C.); (K.G.K.); (V.S.)
| | - Tom Decroo
- Department of Clinical Sciences, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
- Research Foundation Flanders, 1000 Brussels, Belgium
| | - Armand Van Deun
- Mycobacteriology Unit, Institute of Tropical Medicine, 2000 Antwerp, Belgium;
| | - Alberto Piubello
- International Union Against Tuberculosis and Lung Disease, 75006 Paris, France; (A.P.); (C.-Y.C.); (K.G.K.); (V.S.)
- Damien Foundation, POBox 1065, Niamey, Niger
| | - Chen-Yuan Chiang
- International Union Against Tuberculosis and Lung Disease, 75006 Paris, France; (A.P.); (C.-Y.C.); (K.G.K.); (V.S.)
- Division of Pulmonary Medicine, Department of Internal Medicine, Wanfang Hospital, Taipei Medical University, Taipei 11696, Taiwan
- Division of Pulmonary Medicine, Department of Internal Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan
| | - Kobto G. Koura
- International Union Against Tuberculosis and Lung Disease, 75006 Paris, France; (A.P.); (C.-Y.C.); (K.G.K.); (V.S.)
- COMUE Sorbonne Paris Cité, Université Paris Descartes, Faculté des Sciences Pharmaceutiques et Biologiques, 75006 Paris, France
- École Nationale de Formation des Techniciens Supérieurs en Santé Publique et en Surveillance Epidémiologique, Université de Parakou, Parakou, Benin
| | - Valérie Schwoebel
- International Union Against Tuberculosis and Lung Disease, 75006 Paris, France; (A.P.); (C.-Y.C.); (K.G.K.); (V.S.)
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14
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In Vitro Susceptibility of Mycobacterium tuberculosis to Amikacin, Kanamycin, and Capreomycin. Antimicrob Agents Chemother 2018; 62:AAC.01724-17. [PMID: 29311078 DOI: 10.1128/aac.01724-17] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 12/13/2017] [Indexed: 11/20/2022] Open
Abstract
Amikacin, kanamycin, and capreomycin are among the most important second-line drugs for multidrug-resistant tuberculosis. Although amikacin and kanamycin are administered at the same dose and show the same pharmacokinetics, they have different WHO breakpoints, suggesting that the two drugs have different MICs. The aim of this study was to investigate possible differences in MICs between the aminoglycosides and capreomycin. Using the direct concentration method, a range of concentrations of amikacin, kanamycin, and capreomycin (0.25, 0.50, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0, and 64.0 mg/liter) were tested against 57 clinical Mycobacterium tuberculosis strains. The 7H10 agar plates were examined for mycobacterial growth after 14 days. At 2 mg/liter, 48 strains (84%) were inhibited by amikacin and only 5 strains (9%) were inhibited by kanamycin (P < 0.05, Wilcoxon signed-rank test). The median MICs of amikacin, kanamycin, and capreomycin were 2, 4, and 8 mg/liter, respectively. No difference in amikacin, kanamycin, and capreomycin MIC distributions was observed between multidrug-resistant strains and fully susceptible strains. The results indicate that amikacin is more active than kanamycin and capreomycin against M. tuberculosis with the absolute concentration method. Determination of the impact of this difference on clinical outcomes in daily practice requires a prospective study, including pharmacokinetic and pharmacodynamic evaluations.
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15
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Molecular Investigation of Resistance to Second-Line Injectable Drugs in Multidrug-Resistant Clinical Isolates of Mycobacterium tuberculosis in France. Antimicrob Agents Chemother 2017; 61:AAC.01299-16. [PMID: 27895017 DOI: 10.1128/aac.01299-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 11/03/2016] [Indexed: 12/14/2022] Open
Abstract
The second-line injectable drugs (SLID, i.e., amikacin, kanamycin, capreomycin) are key drugs for the treatment of multidrug-resistant tuberculosis. Mutations in rrs region 1400, tlyA, and eis promoter are associated with resistance to SLID, to capreomycin, and to kanamycin, respectively. In this study, the sequencing data of SLID resistance-associated genes were compared to the results of phenotypic drug susceptibility testing by the proportion method for the SLID in 206 multidrug-resistant clinical isolates of Mycobacterium tuberculosis collected in France. Among the 153 isolates susceptible to the 3 SLID, 145 showed no mutation, 1 harbored T1404C and G1473A mutations in rrs, and 7 had an eis promoter mutation. Among the 53 strains resistant to at least 1 of the SLID, mutations in rrs accounted for resistance to amikacin, capreomycin, and kanamycin for 81%, 75%, and 44% of the isolates, respectively, while mutations in eis promoter were detected in 44% of the isolates resistant to kanamycin. In contrast, no mutations in tlyA were observed in the isolates resistant to capreomycin. The discrepancies observed between the genotypic (on the primary culture) and phenotypic drug susceptibility testing were explained by (i) resistance to SLID with MICs close to the critical concentration used for routine DST and not detected by phenotypic testing (n = 8, 15% of SLID-resistant strains), (ii) low-frequency heteroresistance not detected by sequencing of drug resistance-associated genes on the primary culture (n = 8, 15% of SLID-resistant strains), and (iii) other resistance mechanisms not yet characterized (n = 7, 13% of SLID-resistant strains).
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16
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Ellington MJ, Ekelund O, Aarestrup FM, Canton R, Doumith M, Giske C, Grundman H, Hasman H, Holden MTG, Hopkins KL, Iredell J, Kahlmeter G, Köser CU, MacGowan A, Mevius D, Mulvey M, Naas T, Peto T, Rolain JM, Samuelsen Ø, Woodford N. The role of whole genome sequencing in antimicrobial susceptibility testing of bacteria: report from the EUCAST Subcommittee. Clin Microbiol Infect 2016; 23:2-22. [PMID: 27890457 DOI: 10.1016/j.cmi.2016.11.012] [Citation(s) in RCA: 317] [Impact Index Per Article: 39.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 11/18/2016] [Indexed: 12/11/2022]
Abstract
Whole genome sequencing (WGS) offers the potential to predict antimicrobial susceptibility from a single assay. The European Committee on Antimicrobial Susceptibility Testing established a subcommittee to review the current development status of WGS for bacterial antimicrobial susceptibility testing (AST). The published evidence for using WGS as a tool to infer antimicrobial susceptibility accurately is currently either poor or non-existent and the evidence / knowledge base requires significant expansion. The primary comparators for assessing genotypic-phenotypic concordance from WGS data should be changed to epidemiological cut-off values in order to improve differentiation of wild-type from non-wild-type isolates (harbouring an acquired resistance). Clinical breakpoints should be a secondary comparator. This assessment will reveal whether genetic predictions could also be used to guide clinical decision making. Internationally agreed principles and quality control (QC) metrics will facilitate early harmonization of analytical approaches and interpretive criteria for WGS-based predictive AST. Only data sets that pass agreed QC metrics should be used in AST predictions. Minimum performance standards should exist and comparative accuracies across different WGS laboratories and processes should be measured. To facilitate comparisons, a single public database of all known resistance loci should be established, regularly updated and strictly curated using minimum standards for the inclusion of resistance loci. For most bacterial species the major limitations to widespread adoption for WGS-based AST in clinical laboratories remain the current high-cost and limited speed of inferring antimicrobial susceptibility from WGS data as well as the dependency on previous culture because analysis directly on specimens remains challenging. For most bacterial species there is currently insufficient evidence to support the use of WGS-inferred AST to guide clinical decision making. WGS-AST should be a funding priority if it is to become a rival to phenotypic AST. This report will be updated as the available evidence increases.
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Affiliation(s)
- M J Ellington
- Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, National Infection Service, Public Health England, London, UK
| | - O Ekelund
- Department of Clinical Microbiology and the EUCAST Development Laboratory, Kronoberg Region, Central Hospital, Växjö, Sweden
| | - F M Aarestrup
- National Food Institute, Research Group for Genomic Epidemiology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - R Canton
- Servicio de Microbiología, Hospital Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria, Madrid, Spain
| | - M Doumith
- Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, National Infection Service, Public Health England, London, UK
| | - C Giske
- Department of Laboratory Medicine, Karolinska Institute and Karolinska University Hospital, Stockholm, Sweden
| | - H Grundman
- University Medical Centre Freiburg, Infection Prevention and Hospital Hygiene, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - H Hasman
- Statens Serum Institute, Department of Microbiology and Infection Control, Copenhagen, Denmark
| | - M T G Holden
- School of Medicine, Medical & Biological Sciences, North Haugh, University of St Andrews, UK
| | - K L Hopkins
- Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, National Infection Service, Public Health England, London, UK
| | - J Iredell
- Westmead Institute for Medical Research, University of Sydney and Marie Bashir Institute, Sydney, NSW, Australia
| | - G Kahlmeter
- Department of Clinical Microbiology and the EUCAST Development Laboratory, Kronoberg Region, Central Hospital, Växjö, Sweden
| | - C U Köser
- Department of Medicine, University of Cambridge, Cambridge, UK
| | - A MacGowan
- Department of Medical Microbiology, North Bristol NHS Trust, Southmead Hospital, Bristol, UK
| | - D Mevius
- Central Veterinary Institute (CVI) part of Wageningen University and Research Centre (WUR), Lelystad, The Netherlands; Department of Infectious Diseases and Immunology, Utrecht University, Utrecht, The Netherlands
| | - M Mulvey
- National Microbiology Laboratory, Winnipeg, Manitoba, Canada
| | - T Naas
- French National Reference Centre for Antibiotic Resistance, Bacteriology-Hygiene unit, Hôpital Bicêtre, APHP, LabEx LERMIT, University Paris Sud, Le Kremlin-Bicêtre, France
| | - T Peto
- Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - J-M Rolain
- PU-PH des Disciplines Pharmaceutiques, 1-URMITE CNRS IRD UMR 6236, IHU Méditerranée Infection, Valorization and Transfer, Aix Marseille Université, Faculté de Médecine et de Pharmacie, Marseille, France
| | - Ø Samuelsen
- Norwegian National Advisory Unit on Detection of Antimicrobial Resistance, University Hospital of North Norway, Department of Microbiology and Infection Control, Tromsø, Norway
| | - N Woodford
- Antimicrobial Resistance and Healthcare Associated Infections (AMRHAI) Reference Unit, National Infection Service, Public Health England, London, UK.
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17
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Amikacin Optimal Exposure Targets in the Hollow-Fiber System Model of Tuberculosis. Antimicrob Agents Chemother 2016; 60:5922-7. [PMID: 27458215 PMCID: PMC5038304 DOI: 10.1128/aac.00961-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 07/16/2016] [Indexed: 11/20/2022] Open
Abstract
Aminoglycosides such as amikacin are currently used for the treatment of multidrug-resistant tuberculosis (MDR-TB). However, formal pharmacokinetic/pharmacodynamic (PK/PD) studies to identify amikacin exposures and dosing schedules that optimize Mycobacterium tuberculosis killing have not been performed. It is believed that aminoglycosides do not work well under acidic conditions, which, if true, would mean poor sterilizing activity against semidormant bacilli at low pH. We performed time-kill studies to compare the bactericidal effect of amikacin in log-phase-growth bacilli with the sterilizing effect in semidormant bacilli at pH 5.8 in broth. In log-phase M. tuberculosis at normal pH versus semidormant M. tuberculosis at pH 5.8, the maximal kill (Emax) estimate and 95% confidence interval (CI) were 5.39 (95% CI, 4.91 to 5.63) versus 4.88 (CI, 4.46 to 5.22) log10 CFU/ml, while the concentration mediating 50% of Emax (EC50) was 1.0 (CI, 0. 0.86 to 1.12) versus 0.60 (CI, 0.50 to 0.66) times the MIC, respectively. Thus, the optimal exposures and kill rates identified for log-phase M. tuberculosis will be optimal even for semidormant bacilli. Next, we performed exposure-response and dose-scheduling studies in the hollow-fiber system model of tuberculosis using log-phase M. tuberculosis We recapitulated the amikacin concentration-time profiles observed in lungs of patients treated over 28 days. The PK/PD index linked to M. tuberculosis kill was the peak concentration (Cmax)-to-MIC ratio (r(2) > 0.99), closely followed by the area under the concentration-time curve from 0 to 24 h (AUC0-24)-to-MIC ratio (r(2) = 0.98). The EC90 was a Cmax/MIC ratio of 10.13 (95% CI, 7.73 to 12.48). The EC90 is the dosing target for intermittent therapy that optimizes cure in TB programs for MDR-TB patients.
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A Multilaboratory, Multicountry Study To Determine MIC Quality Control Ranges for Phenotypic Drug Susceptibility Testing of Selected First-Line Antituberculosis Drugs, Second-Line Injectables, Fluoroquinolones, Clofazimine, and Linezolid. J Clin Microbiol 2016; 54:2963-2968. [PMID: 27654338 DOI: 10.1128/jcm.01138-16] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2016] [Accepted: 09/19/2016] [Indexed: 11/20/2022] Open
Abstract
Our objective was to establish reference MIC quality control (QC) ranges for drug susceptibility testing of antimycobacterials, including first-line agents, second-line injectables, fluoroquinolones, and World Health Organization category 5 drugs for multidrug-resistant tuberculosis using a 7H9 broth microdilution MIC method. A tier-2 reproducibility study was conducted in eight participating laboratories using Clinical Laboratory and Standards Institute (CLSI) guidelines. Three lots of custom-made frozen 96-well polystyrene microtiter plates were used and prepared with 2× prediluted drugs in 7H9 broth-oleic acid albumin dextrose catalase. The QC reference strain was Mycobacterium tuberculosis H37Rv. MIC frequency, mode, and geometric mean were calculated for each drug. QC ranges were derived based on predefined, strict CLSI criteria. Any data lying outside CLSI criteria resulted in exclusion of the entire laboratory data set. Data from one laboratory were excluded due to higher MIC values than other laboratories. QC ranges were established for 11 drugs: isoniazid (0.03 to 0.12 μg/ml), rifampin (0.03 to 0.25 μg/ml), ethambutol (0.25 to 2 μg/ml), levofloxacin (0.12 to 1 μg/ml), moxifloxacin (0.06 to 0.5 μg/ml), ofloxacin (0.25 to 2 μg/ml), amikacin (0.25 to 2 μg/ml), kanamycin (0.25 to 2 μg/ml), capreomycin (0.5 to 4 μg/ml), linezolid (0.25 to 2 μg/ml), and clofazimine (0.03 to 0.25 μg/ml). QC ranges could not be established for nicotinamide (pyrazinamide surrogate), prothionamide, or ethionamide, which were assay nonperformers. Using strict CLSI criteria, QC ranges against the M. tuberculosis H37Rv reference strain were established for the majority of commonly used antituberculosis drugs, with a convenient 7H9 broth microdilution MIC method suitable for use in resource-limited settings.
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19
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Dafale NA, Semwal UP, Rajput RK, Singh G. Selection of appropriate analytical tools to determine the potency and bioactivity of antibiotics and antibiotic resistance. J Pharm Anal 2016; 6:207-213. [PMID: 29403984 PMCID: PMC5762606 DOI: 10.1016/j.jpha.2016.05.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 02/29/2016] [Accepted: 05/23/2016] [Indexed: 11/21/2022] Open
Abstract
Antibiotics are the chemotherapeutic agents that kill or inhibit the pathogenic microorganisms. Resistance of microorganism to antibiotics is a growing problem around the world due to indiscriminate and irrational use of antibiotics. In order to overcome the resistance problem and to safely use antibiotics, the correct measurement of potency and bioactivity of antibiotics is essential. Microbiological assay and high performance liquid chromatography (HPLC) method are used to quantify the potency of antibiotics. HPLC method is commonly used for the quantification of potency of antibiotics, but unable to determine the bioactivity; whereas microbiological assay estimates both potency and bioactivity of antibiotics. Additionally, bioassay is used to estimate the effective dose against antibiotic resistant microbes. Simultaneously, microbiological assay addresses the several parameters such as minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC), mutation prevention concentration (MPC) and critical concentration (Ccr) which are used to describe the potency in a more informative way. Microbiological assay is a simple, sensitive, precise and cost effective method which gives reproducible results similar to HPLC. However, the HPLC cannot be a complete substitute for microbiological assay and both methods have their own significance to obtain more realistic and precise results.
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Affiliation(s)
- Nishant A. Dafale
- Correspondence to: CSIR-National Environmental Engineering Research Institute (NEERI), Nagpur, India.CSIR-National Environmental Engineering Research Institute (NEERI)NagpurIndia
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20
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Ahmad S, Mokaddas E, Al-Mutairi N, Eldeen HS, Mohammadi S. Discordance across Phenotypic and Molecular Methods for Drug Susceptibility Testing of Drug-Resistant Mycobacterium tuberculosis Isolates in a Low TB Incidence Country. PLoS One 2016; 11:e0153563. [PMID: 27096759 PMCID: PMC4838278 DOI: 10.1371/journal.pone.0153563] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/31/2016] [Indexed: 11/18/2022] Open
Abstract
With increasing incidence of multidrug-resistant tuberculosis (MDR-TB), accurate drug susceptibility testing (DST) of Mycobacterium tuberculosis to first-line drugs has become crucial for proper patient management. We evaluated concordance of DST results for 70 M. tuberculosis isolates across two phenotypic and two molecular methods: BACTEC 460TB, MGIT 960 system, GenoType MTBDRplus and DNA sequencing of gene segments most commonly implicated in conferring resistance to anti-TB drugs. Most (84%) M. tuberculosis isolates were multidrug-resistant. Twenty-four isolates yielded discrepant DST results. For rifampicin, isoniazid and streptomycin, 96%, 97% and 93% of isolates, respectively, were susceptible or resistant by all four methods, whereas for ethambutol, this agreement was observed for only 76% of isolates (P<0.05 for rifampicin or isoniazid or streptomycin versus ethambutol). Occurrence of rare mutations in three isolates that confer low-level resistance caused lower agreement for rifampicin among the four methods (kappa coefficient (κ) range, 0.84 to 0.95). For isoniazid, there was perfect agreement among phenotypic methods and molecular methods (κ, 1.00) but lower agreement between phenotypic and molecular methods. Three isolates were detected as polydrug-resistant by MGIT 960 system but as multidrug-resistant by DNA sequence-based method. The agreement was higher for streptomycin among the two phenotypic methods (κ, 0.97) while targeted sequencing yielded lower agreement (κ range, 0.86 to 0.89). The discrepancy for ethambutol resulted largely due to lower concordance of MGIT 960 results (κ range, 0.53 to 0.64). The MGIT 960 system is an accurate method for DST of M. tuberculosis against isoniazid and streptomycin while the results of rifampicin susceptibility should be complemented with DNA sequencing-based method when the suspicion for resistance is high. The possibility of false susceptibility to ethambutol with MGIT 960 system suggests that molecular or other phenotypic methods may be more useful when accurate ethambutol susceptibility results are warranted.
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Affiliation(s)
- Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
- * E-mail:
| | - Eiman Mokaddas
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
- Kuwait National TB Reference Laboratory, Shuwaikh, Kuwait
| | - Noura Al-Mutairi
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | | | - Shirin Mohammadi
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
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21
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Georghiou SB, Ajbani K, Rodrigues C, Rodwell TC. Performance of a pyrosequencing platform in diagnosing drug-resistant extra-pulmonary tuberculosis in India. Int J Tuberc Lung Dis 2016; 20:160-5. [PMID: 26792466 DOI: 10.5588/ijtld.15.0459] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
SETTING Pyrosequencing diagnostic assays have shown great utility in identifying and characterizing pulmonary drug-resistant tuberculosis (TB) infections. However, the method has yet to be evaluated for the diagnosis of drug-resistant extra-pulmonary TB (EPTB). OBJECTIVE To evaluate the performance of a pyrosequencing platform in establishing molecular drug resistance profiles for 79 clinical EPTB specimens at a referral center for drug-resistant TB in India. DESIGN Genotypic drug resistance profiles were established for all 79 non-pulmonary, culture-positive TB clinical specimens. Acid-fast bacilli smear microscopy, MGIT™ 960™ culture and drug susceptibility testing were performed on all specimens for reference. RESULTS In comparison to MGIT 960, the sensitivity and specificity of pyrosequencing in detecting drug resistance among specimens was found to be respectively 100% and 100%, 67% and 98%, and 100% and 100% for isoniazid, rifampicin, and the fluoroquinolones. No EPTB specimens were phenotypically resistant to any of the injectables, but the specificity of the assay was determined to be 100%, 98%, and 98% for amikacin, kanamycin, and capreomycin. CONCLUSIONS Pyrosequencing is a rapid, appropriate technology for the diagnosis of isoniazid-, fluoroquinolone-, and potentially injectable drug-resistant EPTB clinical specimens, and should be considered as an alternative to conventional growth-based diagnostic methods for EPTB when resistance to these drugs is suspected.
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Affiliation(s)
- S B Georghiou
- Division of Global Public Health, School of Medicine, University of California San Diego, La Jolla, California, USA
| | - K Ajbani
- Section Microbiology, Department of Laboratory Medicine, P D Hinduja National Hospital and Medical Research Centre, Mumbai, India
| | - C Rodrigues
- Section Microbiology, Department of Laboratory Medicine, P D Hinduja National Hospital and Medical Research Centre, Mumbai, India
| | - T C Rodwell
- Division of Global Public Health, School of Medicine, University of California San Diego, La Jolla, California, USA
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22
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Li G, Zhang J, Li C, Guo Q, Jiang Y, Wei J, Qiu Y, Zhao X, Zhao LL, Lu J, Wan K. Antimycobacterial activity of five efflux pump inhibitors against Mycobacterium tuberculosis clinical isolates. J Antibiot (Tokyo) 2015; 69:173-5. [PMID: 26464012 DOI: 10.1038/ja.2015.101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 08/20/2015] [Accepted: 09/07/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Guilian Li
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jingrui Zhang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Laboratory, Shijiazhuang Obstetrics and Gynecology Hospital, the Fourth Hospital of Shijiazhuang, Shijiazhuang, China.,Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
| | - Chao Li
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
| | - Qian Guo
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Pathogenic Biology Institute, University of South China, Hengyang, China
| | - Yi Jiang
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jianhao Wei
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
| | - Yan Qiu
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Xiuqin Zhao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Li-li Zhao
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Jianxin Lu
- Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
| | - Kanglin Wan
- State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.,Key Laboratory of Laboratory Medicine, Wenzhou Medical College, Wenzhou, China
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23
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Dijkstra J, van Altena R, Akkerman O, de Lange W, Proost J, van der Werf T, Kosterink J, Alffenaar J. Limited sampling strategies for therapeutic drug monitoring of amikacin and kanamycin in patients with multidrug-resistant tuberculosis. Int J Antimicrob Agents 2015; 46:332-7. [DOI: 10.1016/j.ijantimicag.2015.06.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 05/28/2015] [Accepted: 06/01/2015] [Indexed: 11/16/2022]
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24
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Kahlmeter G. The 2014 Garrod Lecture: EUCAST – are we heading towards international agreement? J Antimicrob Chemother 2015; 70:2427-39. [DOI: 10.1093/jac/dkv145] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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25
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Torrea G, Coeck N, Desmaretz C, Van De Parre T, Van Poucke T, Lounis N, de Jong BC, Rigouts L. Bedaquiline susceptibility testing of Mycobacterium tuberculosis in an automated liquid culture system. J Antimicrob Chemother 2015; 70:2300-5. [PMID: 25977401 DOI: 10.1093/jac/dkv117] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/02/2015] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The objective of this study was to evaluate the performance of the BACTEC MGIT960 system to test the susceptibility to bedaquiline for Mycobacterium tuberculosis complex. METHODS We determined the quality control (QC) range of bedaquiline using the M. tuberculosis H37Rv reference strain and the epidemiological cut-off (ECOFF) in MGIT960 and on Middlebrook 7H11 agar (M7H11) using 47 strains from bedaquiline treatment-naive patients. The accuracy of MGIT960 was evaluated versus M7H11 using 74 'probably susceptible to bedaquiline' and 18 'probably resistant to bedaquiline' strains. Repeatability and reproducibility of MGIT960 were assessed using five strains showing different resistance levels. RESULTS The QC range for the H37Rv strain was between 0.125 and 0.50 mg/L. The WT MIC distribution ranged from ≤0.03 to 1.00 mg/L in MGIT960 and from ≤0.008 to 0.25 mg/L on M7H11 with suggested ECOFFs of 1.00 and 0.25 mg/L, respectively. Applying these ECOFFs, the probably susceptible and probably resistant strains were distinguishable by both methods, albeit with only a 2-fold increased MIC for one of the resistant strains compared with the ECOFF. Intermethod agreement to classify the isolates was excellent (100%). All replicates in the repeatability and reproducibility experiments fell within the normal range. CONCLUSIONS The MGIT960 system proved to be highly stable, reproducible and accurate relative to the M7H11 agar method for determining the bedaquiline MIC. The small margin between the suggested ECOFF and the lowest MIC for the mutant strains risks making both methods prone to discordant results. Further validation in clinical settings linked to treatment outcome data is needed.
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Affiliation(s)
- Gabriela Torrea
- Department of Biomedical Sciences, Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Nele Coeck
- Department of Biomedical Sciences, Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Christel Desmaretz
- Department of Biomedical Sciences, Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium
| | - Tim Van De Parre
- Quality Department, Institute of Tropical Medicine, Antwerp, Belgium
| | - Tijs Van Poucke
- Quality Department, Institute of Tropical Medicine, Antwerp, Belgium
| | - Nacer Lounis
- Clinical Virology Department, Janssen Infectious Diseases, Beerse, Belgium
| | - Bouke C de Jong
- Department of Biomedical Sciences, Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium Department of Medicine, Division of Infectious Diseases, New York University, New York, NY, USA Vaccinology Department, Medical Research Council Unit, Fajara, The Gambia
| | - Leen Rigouts
- Department of Biomedical Sciences, Mycobacteriology Unit, Institute of Tropical Medicine, Antwerp, Belgium Department of Biomedical Sciences, Antwerp University, Antwerp, Belgium
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Ajbani K, Lin SYG, Rodrigues C, Nguyen D, Arroyo F, Kaping J, Jackson L, Garfein RS, Catanzaro D, Eisenach K, Victor TC, Crudu V, Gler MT, Ismail N, Desmond E, Catanzaro A, Rodwell TC. Evaluation of pyrosequencing for detecting extensively drug-resistant Mycobacterium tuberculosis among clinical isolates from four high-burden countries. Antimicrob Agents Chemother 2015; 59:414-20. [PMID: 25367911 PMCID: PMC4291380 DOI: 10.1128/aac.03614-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2014] [Accepted: 10/28/2014] [Indexed: 12/15/2022] Open
Abstract
Reliable molecular diagnostics, which detect specific mutations associated with drug resistance, are promising technologies for the rapid identification and monitoring of drug resistance in Mycobacterium tuberculosis isolates. Pyrosequencing (PSQ) has the ability to detect mutations associated with first- and second-line anti-tuberculosis (TB) drugs, with the additional advantage of being rapidly adaptable for the identification of new mutations. The aim of this project was to evaluate the performance of PSQ in predicting phenotypic drug resistance in multidrug- and extensively drug-resistant tuberculosis (M/XDR-TB) clinical isolates from India, South Africa, Moldova, and the Philippines. A total of 187 archived isolates were run through a PSQ assay in order to identify M. tuberculosis (via the IS6110 marker), and to detect mutations associated with M/XDR-TB within small stretches of nucleotides in selected loci. The molecular targets included katG, the inhA promoter and the ahpC-oxyR intergenic region for isoniazid (INH) resistance; the rpoB core region for rifampin (RIF) resistance; gyrA for fluoroquinolone (FQ) resistance; and rrs for amikacin (AMK), capreomycin (CAP), and kanamycin (KAN) resistance. PSQ data were compared to phenotypic mycobacterial growth indicator tube (MGIT) 960 drug susceptibility testing results for performance analysis. The PSQ assay illustrated good sensitivity for the detection of resistance to INH (94%), RIF (96%), FQ (93%), AMK (84%), CAP (88%), and KAN (68%). The specificities of the assay were 96% for INH, 100% for RIF, FQ, AMK, and KAN, and 97% for CAP. PSQ is a highly efficient diagnostic tool that reveals specific nucleotide changes associated with resistance to the first- and second-line anti-TB drug medications. This methodology has the potential to be linked to mutation-specific clinical interpretation algorithms for rapid treatment decisions.
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Affiliation(s)
- Kanchan Ajbani
- P. D. Hinduja National Hospital & Medical Research Centre, Department of Microbiology, Veer Sarvarkar Marg, Mahim, Mumbai, India
| | - Shou-Yean Grace Lin
- California Department of Public Health, Microbial Diseases Laboratory, Richmond, California, USA
| | - Camilla Rodrigues
- P. D. Hinduja National Hospital & Medical Research Centre, Department of Microbiology, Veer Sarvarkar Marg, Mahim, Mumbai, India
| | - Duylinh Nguyen
- California Department of Public Health, Microbial Diseases Laboratory, Richmond, California, USA
| | - Francine Arroyo
- California Department of Public Health, Microbial Diseases Laboratory, Richmond, California, USA
| | - Janice Kaping
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Lynn Jackson
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Richard S Garfein
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Donald Catanzaro
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Kathleen Eisenach
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Thomas C Victor
- Division of Molecular Biology and Human Genetics, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Valeru Crudu
- Microbiology and Morphology Laboratory, Institute of Phthisiopneumology, Chisinau, Moldova
| | - Maria Tarcela Gler
- Tropical Disease Foundation/Makati Medical Center, Makati City, Philippines
| | - Nazir Ismail
- National Tuberculosis Reference Laboratory, Johannesburg, South Africa
| | - Edward Desmond
- California Department of Public Health, Microbial Diseases Laboratory, Richmond, California, USA
| | - Antonino Catanzaro
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
| | - Timothy C Rodwell
- Department of Medicine, University of California, San Diego, La Jolla, California, USA
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Disparities in capreomycin resistance levels associated with the rrs A1401G mutation in clinical isolates of Mycobacterium tuberculosis. Antimicrob Agents Chemother 2014; 59:444-9. [PMID: 25385119 DOI: 10.1128/aac.04438-14] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
As the prevalence of multidrug-resistant and extensively drug-resistant tuberculosis strains continues to rise, so does the need to develop accurate and rapid molecular tests to complement time-consuming growth-based drug susceptibility testing. Performance of molecular methods relies on the association of specific mutations with phenotypic drug resistance and while considerable progress has been made for resistance detection of first-line antituberculosis drugs, rapid detection of resistance for second-line drugs lags behind. The rrs A1401G allele is considered a strong predictor of cross-resistance between the three second-line injectable drugs, capreomycin (CAP), kanamycin, and amikacin. However, discordance is often observed between the rrs A1401G mutation and CAP resistance, with up to 40% of rrs A1401G mutants being classified as CAP susceptible. We measured the MICs to CAP in 53 clinical isolates harboring the rrs A1401G mutation and found that the CAP MICs ranged from 8 μg/ml to 40 μg/ml. These results were drastically different from engineered A1401G mutants generated in isogenic Mycobacterium tuberculosis, which exclusively exhibited high-level CAP MICs of 40 μg/ml. These data support the results of prior studies, which suggest that the critical concentration of CAP (10 μg/ml) used to determine resistance by indirect agar proportion may be too high to detect all CAP-resistant strains and suggest that a larger percentage of resistant isolates could be identified by lowering the critical concentration. These data also suggest that differences in resistance levels among clinical isolates are possibly due to second site or compensatory mutations located elsewhere in the genome.
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Little difference between minimum inhibitory concentrations of Mycobacterium tuberculosis wild-type organisms determined with BACTEC MGIT 960 and Middlebrook 7H10. Clin Microbiol Infect 2014; 21:148.e5-7. [PMID: 25640156 DOI: 10.1016/j.cmi.2014.08.021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2014] [Revised: 08/18/2014] [Accepted: 08/20/2014] [Indexed: 11/20/2022]
Abstract
The MIC wild-type (WT) distribution for Mycobacterium tuberculosis in BACTEC 960 MGIT is not defined, which may result in poor reproducibility for drug susceptibility testing (DST), as several DST methods with different breakpoints are in use. In a comparison between MGIT and Middlebrook 7H10 medium of seven first- and second-line drugs, including 133 MIC determinations of 15 WT isolates, we found an agreement of 91.7% within ± one MIC dilution step. The results confirm the agreement in MIC testing between 7H10 and MGIT and indicate that breakpoints could be harmonized in order to avoid misclassification.
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Wedajo W, Schön T, Bedru A, Kiros T, Hailu E, Mebrahtu T, Yamuah L, Ängeby K, Werngren J, Onyebujoh P, Dagne K, Aseffa A. A 24-well plate assay for simultaneous testing of first and second line drugs against Mycobacterium tuberculosis in a high endemic setting. BMC Res Notes 2014; 7:512. [PMID: 25108648 PMCID: PMC4267144 DOI: 10.1186/1756-0500-7-512] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Accepted: 08/07/2014] [Indexed: 11/16/2022] Open
Abstract
Background Early detection of drug resistance is one of the priorities of tuberculosis (TB) control programs as drug resistance is increasing. New molecular assays are only accessible for a minority of the second line drugs and their availability in high endemic settings is also hampered by high cost and logistic challenges. Therefore, we evaluated a previously developed method for drug susceptibility testing (DST) including both first- and second line anti-TB drugs for use in high endemic areas. Results Baseline mycobacterial isolates from 78 consecutive pulmonary TB patients from Addis Ababa, Ethiopia who were culture positive for Mycobacterium tuberculosis at the end of a two-month directly observed treatment short course (DOTS) were included. The isolates were simultaneously tested for isoniazid, rifampicin, ethambutol, streptomycin, amikacin, kanamycin, capreomycin, ofloxacin, moxifloxacin, ethionamide and para-aminosalicylic acid susceptibility using the indirect proportion method adopted for 24-well agar plates containing Middlebrook 7H10 medium. Applying the 24-well plate assay, 43 (55.1%) isolates were resistant to one or more of the first line drugs tested (isoniazid, rifampicin and ethambutol). MDR-TB was identified in 20.5% of this selected group and there was a perfect correlation for rifampicin resistance with the results from the genotype MTBDRplus assay. All isolates were susceptible to aminoglycosides and fluoroquinolones in agreement with the genotype MTBDRsl assay. The only tested second line drug associated to resistance was ethionamide (14.1% resistant). The method was reproducible with stable results for internal controls (one multi-drug resistant (MDR) and one pan-susceptible strain (H37Rv) and DST results could be reported at two weeks. Conclusions The 24-well plate method for simultaneous DST for first- and second line drugs was found to be reproducible and correlated well to molecular drug susceptibility tests. It is likely to be useful in high-endemic areas for surveillance as well as for the detection of second line drug resistance in targeted groups such as in those who fail empirical MDR treatment.
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Affiliation(s)
| | - Thomas Schön
- Department of Medical Microbiology, Linkoping University, Linköping, Sweden.
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Quantification of amikacin and kanamycin in serum using a simple and validated LC–MS/MS method. Bioanalysis 2014; 6:2125-33. [DOI: 10.4155/bio.14.191] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Background: Amikacin and kanamycin are frequently used in the treatment of multidrug-resistant TB. The current commercially available immunoassay is unable to analyze kanamycin and trough levels of amikacin. The objective was therefore to develop a LC–MS/MS method for the quantification of amikacin and kanamycin in human serum. Materials & methods: Using apramycin as internal standard, selectivity, accuracy, precision, recovery, matrix effects and stability were evaluated. Results: The presented LC–MS/MS method meets the recommendations of the US FDA with a low LLOQ of 250 ng/ml for amikacin and 100 ng/ml for kanamycin. No statistical significant difference was found between the LC–MS/MS method and the immunoassay of amikacin (Architect® assay, p = 0.501). Conclusion: The low LLOQ of amikacin and the ability to analyze kanamycin makes the LC–MS/MS method the preferred method for analyzing these aminoglycosides.
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Rodwell TC, Valafar F, Douglas J, Qian L, Garfein RS, Chawla A, Torres J, Zadorozhny V, Kim MS, Hoshide M, Catanzaro D, Jackson L, Lin G, Desmond E, Rodrigues C, Eisenach K, Victor TC, Ismail N, Crudu V, Gler MT, Catanzaro A. Predicting extensively drug-resistant Mycobacterium tuberculosis phenotypes with genetic mutations. J Clin Microbiol 2014; 52:781-9. [PMID: 24353002 PMCID: PMC3957771 DOI: 10.1128/jcm.02701-13] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/12/2013] [Indexed: 01/20/2023] Open
Abstract
Molecular diagnostic methods based on the detection of mutations conferring drug resistance are promising technologies for rapidly detecting multidrug-/extensively drug-resistant tuberculosis (M/XDR TB), but large studies of mutations as markers of resistance are rare. The Global Consortium for Drug-Resistant TB Diagnostics analyzed 417 Mycobacterium tuberculosis isolates from multinational sites with a high prevalence of drug resistance to determine the sensitivities and specificities of mutations associated with M/XDR TB to inform the development of rapid diagnostic methods. We collected M/XDR TB isolates from regions of high TB burden in India, Moldova, the Philippines, and South Africa. The isolates underwent standardized phenotypic drug susceptibility testing (DST) to isoniazid (INH), rifampin (RIF), moxifloxacin (MOX), ofloxacin (OFX), amikacin (AMK), kanamycin (KAN), and capreomycin (CAP) using MGIT 960 and WHO-recommended critical concentrations. Eight genes (katG, inhA, rpoB, gyrA, gyrB, rrs, eis, and tlyA) were sequenced using Sanger sequencing. Three hundred seventy isolates were INHr, 356 were RIFr, 292 were MOXr/OFXr, 230 were AMKr, 219 were CAPr, and 286 were KANr. Four single nucleotide polymorphisms (SNPs) in katG/inhA had a combined sensitivity of 96% and specificities of 97 to 100% for the detection of INHr. Eleven SNPs in rpoB had a combined sensitivity of 98% for RIFr. Eight SNPs in gyrA codons 88 to 94 had sensitivities of 90% for MOXr/OFXr. The rrs 1401/1484 SNPs had 89 to 90% sensitivity for detecting AMKr/CAPr but 71% sensitivity for KANr. Adding eis promoter SNPs increased the sensitivity to 93% for detecting AMKr and to 91% for detecting KANr. Approximately 30 SNPs in six genes predicted clinically relevant XDR-TB phenotypes with 90 to 98% sensitivity and almost 100% specificity.
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Affiliation(s)
- Timothy C. Rodwell
- Department of Medicine, University of California San Diego, San Diego, California, USA
| | - Faramarz Valafar
- Department of Bioinformatics and Medical Informatics, San Diego State University, San Diego, California, USA
| | - James Douglas
- Department of Microbiology, University of Hawaii Manoa, Honolulu, Hawaii, USA
| | - Lishi Qian
- Department of Microbiology, University of Hawaii Manoa, Honolulu, Hawaii, USA
| | - Richard S. Garfein
- Department of Medicine, University of California San Diego, San Diego, California, USA
| | - Ashu Chawla
- Department of Bioinformatics and Medical Informatics, San Diego State University, San Diego, California, USA
| | - Jessica Torres
- Department of Bioinformatics and Medical Informatics, San Diego State University, San Diego, California, USA
| | - Victoria Zadorozhny
- Department of Bioinformatics and Medical Informatics, San Diego State University, San Diego, California, USA
| | - Min Soo Kim
- Department of Bioinformatics and Medical Informatics, San Diego State University, San Diego, California, USA
| | - Matt Hoshide
- Department of Microbiology, University of Hawaii Manoa, Honolulu, Hawaii, USA
| | - Donald Catanzaro
- Department of Bioinformatics and Medical Informatics, San Diego State University, San Diego, California, USA
| | - Lynn Jackson
- Department of Medicine, University of California San Diego, San Diego, California, USA
| | - Grace Lin
- California Department of Public Health, Microbial Diseases Laboratory, Richmond, California, USA
| | - Edward Desmond
- California Department of Public Health, Microbial Diseases Laboratory, Richmond, California, USA
| | | | - Kathy Eisenach
- Department of Pathology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Thomas C. Victor
- Department of Biomedical Sciences, Stellenbosch University, Cape Town, South Africa
| | - Nazir Ismail
- National Tuberculosis Reference Laboratory, Johannesburg, South Africa
| | - Valeru Crudu
- Microbiology and Morphology Laboratory, Institute of Phthisiopneumology, Chisinau, Moldova
| | | | - Antonino Catanzaro
- Department of Medicine, University of California San Diego, San Diego, California, USA
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Current status and future trends in the diagnosis and treatment of drug-susceptible and multidrug-resistant tuberculosis. J Infect Public Health 2013; 7:75-91. [PMID: 24216518 DOI: 10.1016/j.jiph.2013.09.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 08/29/2013] [Accepted: 09/18/2013] [Indexed: 11/21/2022] Open
Abstract
The global burden of tuberculosis (TB) is still large. The increasing incidence of drug-resistant, multidrug-resistant (MDR) (resistant to at least rifampicin and isoniazid), and extensively drug-resistant (XDR) (additionally resistant to a fluoroquinolone and kanamycin/amikacin/capreomycin) strains of Mycobacterium tuberculosis and the association of active disease with human immunodeficiency virus coinfection pose a major threat to TB control efforts. The rapid detection of M. tuberculosis strains and drug susceptibility testing (DST) for anti-TB drugs ensure the provision of effective treatment. Rapid molecular diagnostic and DST methods have been developed recently. Treatment of drug-susceptible TB is effective in ≥95% of disease cases; however, supervised therapy for ≥6 months is challenging. Non-adherence to treatment often results in the evolution of drug-resistant strains of M. tuberculosis due to mutations in the genes encoding drug targets. Sequential accumulation of mutations results in the evolution of MDR and XDR strains of M. tuberculosis. Effective treatment of MDR-TB involves therapy with 5-7 less effective, expensive, and toxic second-line and third-line drugs for ≥24 months and is difficult in most developing countries. XDR-TB is generally an untreatable disease in developing countries. Some currently existing drugs and several new drugs with novel modes of action are in various stages of development to shorten the treatment duration of drug-susceptible TB and to improve the outcome of MDR-TB and XDR-TB.
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Said HM, Kock MM, Ismail NA, Baba K, Omar SV, Osman AG, Hoosen AA, Ehlers MM. Comparison between the BACTEC MGIT 960 system and the agar proportion method for susceptibility testing of multidrug resistant tuberculosis strains in a high burden setting of South Africa. BMC Infect Dis 2012; 12:369. [PMID: 23259765 PMCID: PMC3543708 DOI: 10.1186/1471-2334-12-369] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 12/17/2012] [Indexed: 12/02/2022] Open
Abstract
Background The increasing problem of multi-drug-resistant (MDR) tuberculosis (TB) [ie resistant to at least isoniazid (INH) and rifampicin (RIF)] is becoming a global problem. Successful treatment outcome for MDR-TB depends on reliable and accurate drug susceptibility testing of first-line and second-line anti-TB drugs. Method Consecutive M. tuberculosis isolates identified as MDR-TB during August 2007 to January 2008 using the BACTEC MGIT 960 systems and the agar proportion method were included in this study. Susceptibility testing of MDR-TB isolates against ethambutol (EMB) and streptomycin (STR) as well as two second-line anti-TB drugs, kanamycin (KAN) and ofloxacin (OFX) was performed using the BACTEC MGIT 960 systems at a routine diagnostic laboratory. The results were compared to those obtained by the agar proportion method. Result The agreement between the BACTEC MGIT 960 system and the agar proportion method was 44% for EMB, 61% for STR and 89% for both KAN and OFX. The sensitivity and specificity of the BACTEC MGIT 960 system using the agar proportion method as a gold standard was 92% and 37% for EMB, 95% and 37% for STR, 27% and 97% for KAN and 84% and 90% for OFX, respectively. Conclusions The BACTEC MGIT 960 system showed acceptable sensitivity for EMB, STR, and OFX; however, the BACTEC MGIT 960 system was less specific for EMB and STR and demonstrated a low sensitivity for KAN. The lower agreement found between the two methods suggests the unreliability of the BACTEC MGIT 960 system for the drugs tested. The reasons for the lower agreement between the two methods need to be investigated and further studies are needed in this setting to confirm the study finding.
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Affiliation(s)
- Halima M Said
- Department of Medical Microbiology, Faculty of Health Science, University of Pretoria, Private bag X323, arcadia, Pretoria, 0007, South Africa.
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Ängeby K, Juréen P, Chryssanthou E, Schön T. Tentative susceptibility testing breakpoint for the neuroleptic drug thioridazine, a treatment option for multi- and extensively drug resistant tuberculosis. Int J Mycobacteriol 2012; 1:177-9. [DOI: 10.1016/j.ijmyco.2012.09.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 09/18/2012] [Indexed: 10/27/2022] Open
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Ängeby K, Juréen P, Kahlmeter G, Hoffner SE, Schön T. Challenging a dogma: antimicrobial susceptibility testing breakpoints for Mycobacterium tuberculosis. Bull World Health Organ 2012; 90:693-8. [PMID: 22984314 DOI: 10.2471/blt.11.096644] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2011] [Revised: 03/29/2012] [Accepted: 04/16/2012] [Indexed: 11/27/2022] Open
Abstract
The rise in multidrug-resistant tuberculosis makes it increasingly important that antimicrobial susceptibility testing of Mycobacterium tuberculosis produce clinically meaningful and technically reproducible results. Unfortunately, this is not always the case because mycobacteriology specialists have not followed generally accepted modern principles for the establishment of susceptibility breakpoints for bacterial and fungal pathogens. These principles specifically call for a definition of the minimum inhibitory concentrations (MICs) applicable to organisms without resistance mechanisms (also known as wild-type MIC distributions), to be used in combination with data on clinical outcomes, pharmacokinetics and pharmacodynamics. In a series of papers the authors have defined tentative wild-type MIC distributions for M. tuberculosis and hope that other researchers will follow their example and provide confirmatory data. They suggest that some breakpoints are in need of revision because they either (i) bisect the wild-type distribution, which leads to poor reproducibility in antimicrobial susceptibility testing, or (ii) are substantially higher than the MICs of wild-type organisms without supporting clinical evidence, which may result in some strains being falsely reported as susceptible. The authors recommend, in short, that susceptibility breakpoints for antituberculosis agents be systematically reviewed and revised, if necessary, using the same modern tools now accepted for all other bacteria and fungi by the scientific community and by the European Medicines Agency and the European Centre for Disease Prevention and Control. For several agents this would greatly improve the accuracy and reproducibility of antimicrobial susceptibility testing of M. tuberculosis.
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Affiliation(s)
- Kristian Ängeby
- Department of Clinical Microbiology L2:02, Karolinska Institute, Karolinska University Hospital, Stockholm, 171 76, Sweden.
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Sirgel FA, Tait M, Warren RM, Streicher EM, Böttger EC, van Helden PD, Gey van Pittius NC, Coetzee G, Hoosain EY, Chabula-Nxiweni M, Hayes C, Victor TC, Trollip A. Mutations in therrsA1401G Gene and Phenotypic Resistance to Amikacin and Capreomycin inMycobacterium tuberculosis. Microb Drug Resist 2012; 18:193-7. [DOI: 10.1089/mdr.2011.0063] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Frederick A. Sirgel
- DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Science, Stellenbosch University, Cape Town, South Africa
| | - Marisa Tait
- DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Science, Stellenbosch University, Cape Town, South Africa
| | - Robin M. Warren
- DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Science, Stellenbosch University, Cape Town, South Africa
| | - Elizabeth M. Streicher
- DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Science, Stellenbosch University, Cape Town, South Africa
| | - Erik C. Böttger
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
- National Center for Mycobacteria, University of Zurich, Zurich, Switzerland
| | - Paul D. van Helden
- DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Science, Stellenbosch University, Cape Town, South Africa
| | - Nicolaas C. Gey van Pittius
- DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Science, Stellenbosch University, Cape Town, South Africa
| | - Gerrit Coetzee
- National Health Laboratory Services, Tuberculosis Research Unit, Johannesburg, South Africa
| | | | | | - Cindy Hayes
- National Health Laboratory Services, Port Elizabeth, South Africa
| | - Thomas C. Victor
- DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Science, Stellenbosch University, Cape Town, South Africa
| | - André Trollip
- DST/NRF Centre of Excellence for Biomedical TB Research/MRC Centre for Molecular and Cellular Biology, Division of Molecular Biology and Human Genetics, Faculty of Health Science, Stellenbosch University, Cape Town, South Africa
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Georghiou SB, Magana M, Garfein RS, Catanzaro DG, Catanzaro A, Rodwell TC. Evaluation of genetic mutations associated with Mycobacterium tuberculosis resistance to amikacin, kanamycin and capreomycin: a systematic review. PLoS One 2012; 7:e33275. [PMID: 22479378 PMCID: PMC3315572 DOI: 10.1371/journal.pone.0033275] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 02/12/2012] [Indexed: 11/23/2022] Open
Abstract
Background Rapid molecular diagnostics for detecting multidrug-resistant and extensively drug-resistant tuberculosis (M/XDR-TB) primarily identify mutations in Mycobacterium tuberculosis (Mtb) genes associated with drug resistance. Their accuracy, however, is dependent largely on the strength of the association between a specific mutation and the phenotypic resistance of the isolate with that mutation, which is not always 100%. While this relationship is well established and reliable for first-line anti-TB drugs, rifampin and isoniazid, it is less well-studied and understood for second-line, injectable drugs, amikacin (AMK), kanamycin (KAN) and capreomycin (CAP). Methodology/Principal Findings We conducted a systematic review of all published studies evaluating Mtb mutations associated with resistance to AMK, KAN, CAP in order to characterize the diversity and frequency of mutations as well as describe the strength of the association between specific mutations and phenotypic resistance in global populations. Our objective was to determine the potential utility and reliability of these mutations as diagnostic markers for detecting AMK, KAN and CAP resistance. Mutation data was reviewed for 1,585 unique clinical isolates from four continents and over 18 countries. Mutations in the rrs, tlyA, eis promoter and gidB genes were associated with AMK, KAN and/or CAP resistance. Conclusions/Significance The rrs A1401G mutation was present in the majority of AMK, KAN and CAP resistant Mtb strains reviewed, but was also found in 7% of CAP susceptible strains. The 1401 mutation alone, however, was not found with sufficient frequency to detect more than 70–80% of global Mtb strains resistant to AMK and CAP, and 60% of strains resistant to KAN. Additional mutations in the rrs, eis promoter, tlyA and gidB genes appear to be associated with resistance and could improve sensitivity and specificity of future diagnostics.
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Affiliation(s)
- Sophia B. Georghiou
- Department of Molecular Biology, The Scripps Research Institute, La Jolla, California, United States of America
| | - Marisa Magana
- University of California San Diego Medical Center, San Diego, California, United States of America
| | - Richard S. Garfein
- Division of Global Public Health, University of California San Diego School of Medicine, La Jolla, California, United States of America
| | - Donald G. Catanzaro
- Department of Family and Preventive Medicine, University of California San Diego Health Services Research Center, La Jolla, California, United States of America
| | - Antonino Catanzaro
- University of California San Diego Medical Center, San Diego, California, United States of America
| | - Timothy C. Rodwell
- Division of Global Public Health, University of California San Diego School of Medicine, La Jolla, California, United States of America
- * E-mail:
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Reevaluation of the critical concentration for drug susceptibility testing of Mycobacterium tuberculosis against pyrazinamide using wild-type MIC distributions and pncA gene sequencing. Antimicrob Agents Chemother 2011; 56:1253-7. [PMID: 22203587 DOI: 10.1128/aac.05894-11] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Pyrazinamide (PZA) is a potent first-line agent for the treatment of tuberculosis (TB) with activity also against a significant part of drug-resistant Mycobacterium tuberculosis strains. Since PZA is active only at acid pH, testing for susceptibility to PZA is difficult and insufficiently reproducible. The recommended critical concentration for PZA susceptibility (MIC, 100 mg/liter) used in the Bactec systems (460 and MGIT 960) has not been critically evaluated against wild-type MIC distributions in clinical isolates of Mycobacterium tuberculosis. Using the Bactec MGIT 960 system, we determined the PZA MICs for 46 clinical M. tuberculosis isolates and compared the results to pncA sequencing and previously obtained Bactec 460 data. For consecutive clinical isolates (n = 15), the epidemiological wild-type cutoff (ECOFF) for PZA was 64 mg/liter (MIC distribution range, ≤ 8 to 64 mg/liter), and no pncA gene mutations were detected. In strains resistant in both Bactec systems (n = 18), the PZA MICs ranged from 256 to ≥ 1,024 mg/liter. The discordances between pncA sequencing, susceptibility results in Bactec 460, and MIC determinations in Bactec MGIT 960 were mainly observed in strains with MICs close to or at the ECOFF. We conclude that in general, wild-type and resistant strains were clearly separated and correlated to pncA mutations, although some isolates with MICs close to the ECOFF cause reproducibility problems within and between methods. To solve this issue, we suggest that isolates with MICs of ≤ 64 mg/liter be classified susceptible, that an intermediary category be introduced at 128 mg/liter, and that strains with MICs of >128 mg/liter be classified resistant.
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Seddon JA, Hesseling AC, Marais BJ, McIlleron H, Peloquin CA, Donald PR, Schaaf HS. Paediatric use of second-line anti-tuberculosis agents: a review. Tuberculosis (Edinb) 2011; 92:9-17. [PMID: 22118883 DOI: 10.1016/j.tube.2011.11.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Revised: 09/25/2011] [Accepted: 11/01/2011] [Indexed: 11/18/2022]
Abstract
Childhood multidrug-resistant tuberculosis (MDR-TB) is an emerging global epidemic. With the imminent roll-out of rapid molecular diagnostic tests, more children are likely to be identified and require treatment. As MDR-TB is resistant to the most effective first-line drugs, clinicians will have to rely on second-line medications which are less effective and often associated with more pronounced adverse effects than first-line therapy. Despite the fact that most of these agents were discovered many years ago, robust information is lacking regarding their pharmacokinetic and pharmacodynamic properties, adverse effects and drug interactions, especially in children. Children differ from adults in the way that drugs are administered, the manner in which they are metabolised and in the adverse effects experienced. The interaction of these drugs with human immunodeficiency virus infection and antiretroviral therapy is also poorly documented. This article reviews the available second-line drugs currently used in the treatment of MDR-TB in children and discusses medication properties and adverse effects while potential interactions with antiretroviral therapy are explored.
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Affiliation(s)
- James A Seddon
- Desmond Tutu TB Centre, Faculty of Health Sciences, Stellenbosch University, South Africa.
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In vitro pharmacokinetic/pharmacodynamic models in anti-infective drug development: focus on TB. Future Med Chem 2011; 2:1355-69. [PMID: 21359155 DOI: 10.4155/fmc.10.224] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
For rapid anti-tuberculosis (TB) drug development in vitro pharmacokinetic/pharmacodynamic (PK/PD) models are useful in evaluating the direct interaction between the drug and the bacteria, thereby guiding the selection of candidate compounds and the optimization of their dosing regimens. Utilizing in vivo drug-clearance profiles from animal and/or human studies and simulating them in an in vitro PK/PD model allows the in-depth characterization of antibiotic activity of new and existing antibacterials by generating time–kill data. These data capture the dynamic interplay between mycobacterial growth and changing drug concentration as encountered during prolonged drug therapy. This review focuses on important PK/PD parameters relevant to anti-TB drug development, provides an overview of in vitro PK/PD models used to evaluate the efficacy of agents against mycobacteria and discusses the related mathematical modeling approaches of time–kill data. Overall, it provides an introduction to in vitro PK/PD models and their application as critical tools in evaluating anti-TB drugs.
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Engstrom A, Perskvist N, Werngren J, Hoffner SE, Jureen P. Comparison of clinical isolates and in vitro selected mutants reveals that tlyA is not a sensitive genetic marker for capreomycin resistance in Mycobacterium tuberculosis. J Antimicrob Chemother 2011; 66:1247-54. [DOI: 10.1093/jac/dkr109] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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