Estimation of content of anti-TB drugs supplied at centres of the Revised National TB Control Programme in Tamil Nadu, India.

PubMed

Ramachandran, Geetha; Chandrasekaran, Vedachalam; Hemanth Kumar, Agibothu Kupparam; Dewan, Puneet; Swaminathan, Soumya; Thomas, Aleyamma

2013-09-01

To determine the content of certain antituberculosis (TB) drugs supplied at TB treatment centres of the Revised National TB Control Programme (RNTCP) in the state of Tamil Nadu, India. Eight districts across the state were selected, and the following drugs were collected from five settings (District TB centre, TB unit, designated microscopy centres, DOT providers) in each district: rifampicin (150 and 450 mg), isoniazid (300 mg), pyrazinamide (500 and 750 mg), ethambutol (400 and 600 mg), ethionamide (250 mg), levofloxacin (500 mg) and cycloserine (250 mg). A maximum of 10 tablets/capsules were collected from each setting. The drugs were coded prior to analysis. All drugs were assayed by validated spectrophotometric methods. The acceptable limits for drug content were taken as 90-110% of the stated content. More than 90% of tablets of rifampicin 450 mg, isoniazid 300 mg, pyrazinamide 500 and 750 mg, ethambutol 400 and 600 mg and ethionamide 250 mg were within acceptable limits. Eighty per cent of rifampicin 150 mg, 21% of cycloserine 250 mg and 87% of levofloxacin 500 mg were within acceptable limits. The mean cycloserine content was below the acceptable limit in all districts, the mean drug content being 200 mg (range: 108-245 mg). This systematic study showed that the stated drug content of cycloserine was not reached in all districts. Deterioration of cycloserine could be minimised by storing the drug in refrigerators. The geographical location of the districts had no influence on the drug content. © 2013 John Wiley & Sons Ltd.

Beyond multidrug-resistant tuberculosis in Europe: a TBNET study.

PubMed

Günther, G; van Leth, F; Altet, N; Dedicoat, M; Duarte, R; Gualano, G; Kunst, H; Muylle, I; Spinu, V; Tiberi, S; Viiklepp, P; Lange, C

2015-12-01

The emergence of drug-resistant tuberculosis (TB) is a challenge to TB control in Europe. We evaluated second-line drug susceptibility testing in Mycobacterium tuberculosis isolates from patients with multidrug-resistant, pre-extensively drug-resistant (pre-XDR-TB) and XDR-TB at 23 TBNET sites in 16 European countries. Over 30% of bacilli from patients with pre-XDR-TB showed resistance to any fluoroquinolone and almost 70% to any second-line injectable drug. Respectively >90% and >80% of the XDR-TB strains tested showed phenotypic resistance to pyrazinamide and ethambutol. Resistance to prothionamide/ethionamide was high in bacilli from pre-XDR-TB patients (43%) and XDR-TB patients (49%).

The safety of antituberculosis medications during breastfeeding.

PubMed

Tran, J H; Montakantikul, P

1998-12-01

Most antituberculosis drugs appear to be safe for use with breastfeeding. These agents are excreted in breast milk at relatively small concentrations. No adverse effects have been reported to date. The percentages of the therapeutic dose of antituberculosis agents that potentially may be delivered to the nursing infants range from 0.05% to 28%. Currently isoniazid, rifampin, ethambutol, streptomycin (first-line agents), kanamycin and cycloserine (second-line agents) are the only agents considered by the AAP to be compatible with breastfeeding. Unfortunately, there are still no clear data on the safety of pyrazinamide, ethionamide, and capreomycin during breastfeeding. If the mother chooses to breastfeed, it may be prudent to examine the infant for signs and symptoms of toxicity. In infants requiring treatment with antituberculosis agents, it is important to use therapeutic doses since drug concentrations in breast milk are not adequate as effective therapy for treatment or prevention. However, dosing at the lower end of the therapeutic range should be prescribed (i.e., 10 mg/kg/day of isoniazid) to decrease the risk of toxicity.

Malachite green interferes with postantibiotic recovery of mycobacteria.

PubMed

Gelman, Ekaterina; McKinney, John D; Dhar, Neeraj

2012-07-01

The genus Mycobacterium comprises slow-growing species with generation times ranging from hours to weeks. The protracted incubation time before colonies appear on solid culture medium can result in overgrowth by faster-growing microorganisms. To prevent contamination, the solid media used in laboratories and clinics for cultivation of mycobacteria contain the arylmethane compound malachite green, which has broad-spectrum antimicrobial activity. Malachite green has no impact on the plating efficiency of mycobacteria when cells are grown under normal conditions. However, we found that malachite green interfered with colony formation when bacteria were preexposed to antibiotics targeting cell wall biogenesis (isoniazid, ethionamide, ethambutol). This inhibitory effect of malachite green was not observed when bacteria were preexposed to antibiotics targeting cellular processes other than cell wall biogenesis (rifampin, moxifloxacin, streptomycin). Sputum specimens from tuberculosis patients are routinely evaluated on solid culture medium containing high concentrations of malachite green. This practice could lead to underestimation of bacterial loads and overestimation of chemotherapeutic efficacy.

Malachite Green Interferes with Postantibiotic Recovery of Mycobacteria

PubMed Central

Gelman, Ekaterina; McKinney, John D.

2012-01-01

The genus Mycobacterium comprises slow-growing species with generation times ranging from hours to weeks. The protracted incubation time before colonies appear on solid culture medium can result in overgrowth by faster-growing microorganisms. To prevent contamination, the solid media used in laboratories and clinics for cultivation of mycobacteria contain the arylmethane compound malachite green, which has broad-spectrum antimicrobial activity. Malachite green has no impact on the plating efficiency of mycobacteria when cells are grown under normal conditions. However, we found that malachite green interfered with colony formation when bacteria were preexposed to antibiotics targeting cell wall biogenesis (isoniazid, ethionamide, ethambutol). This inhibitory effect of malachite green was not observed when bacteria were preexposed to antibiotics targeting cellular processes other than cell wall biogenesis (rifampin, moxifloxacin, streptomycin). Sputum specimens from tuberculosis patients are routinely evaluated on solid culture medium containing high concentrations of malachite green. This practice could lead to underestimation of bacterial loads and overestimation of chemotherapeutic efficacy. PMID:22526306

[MOLECULAR CHARACTERISTICS OF THE MULTIDRUG-RESISTANT MYCOBACTERIUM TUBERCULOSIS STRAINS IN THE NORTHWEST RUSSIA].

PubMed

Vyazovaya, A A; Mokrousov, I V; Zhuravlev, V Yu; Solovieva, N S; Otten, T F; Manicheva, O A; Vishnevsky, B I; Narvskaya, O V

2016-01-01

The goal of this work was to study the genotypic characteristics of the multidrug-resistant (MDR, i.e., resistant to at least rifampicine and isoniazid) Mycobacterium tuberculosis strains isolated in 2011-2012 from tuberculosis (TB) patients in the Northwest Russia. Spoligotyping of 195 M. tuberculosis isolates identified 14 different spoligotypes and assigned isolates to the genetic families Beijing (n = 162, 83%), LAM (n = 15), H3/URAL (n = 14), as well as T, Haarlem and X. Spoligotypes SIT1 (Beijing), SIT42 (LAM) and SIT262 (H3/URAL) were the most prevalent. Irrespective to the genotype, all the isolates were resistant to streptomycin. The multidrug resistance was accompanied by the resistance to ethionamide (56%), amikacin (31%), kanamycin (40%), and capreomycin (33%). The ethambutol resistance was found in 71% (n = 115) and 42% (n = 14) of the Beijing and non-Beijing strains, respectively (p < 0.05). In conclusion, the multidrug resistant M. tuberculosis population circulating in the Northwest Russia continues to be dominated by the Beijing family strains.

Adjuvant strategies for potentiation of antibiotics to overcome antimicrobial resistance.

PubMed

Pieren, Michel; Tigges, Marcel

2012-10-01

Alarming facts about the occurrence and spreading of multiple antibiotic resistant bacteria have caught the attention of global surveillance authorities and public media. The demand for novel effective antimicrobial drugs is high and on the rise while, at the same time, the supply of fresh 'magic bullets' is drying up. This review summarizes examples of recent strategies for development of adjunctive antibiotic therapies that overcome microbial resistance and thus rejuvenate the existing arsenal of drugs. Recent studies have demonstrated the potential of compounds that inhibit the action of the repressor protein implicated in ethionamide resistance, thus stimulating activation of the drug and thereby restoring the activity of the antibiotic for treatment of Mycobacterium tuberculosis. Such specific interference with regulators or signal transduction mechanisms involved in antibiotic resistance or virulence provides a new toolbox for novel combinations of antimicrobial drugs with adjuvant molecules lacking intrinsic antibiotic activity. In addition to the development of new antibiotics and vaccination initiatives this strategy of restoring or potentiating the activity of existing antibiotics may help to postpone the day when antibiotics are no longer generally efficacious. Copyright © 2012 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirode, Mitsuhiro; Ono, Atsushi; Miyagishima, Toshikazu

We have constructed a large-scale transcriptome database of rat liver treated with various drugs. In an effort to identify a biomarker for diagnosis of hepatic phospholipidosis, we extracted 78 probe sets of rat hepatic genes from data of 5 drugs, amiodarone, amitriptyline, clomipramine, imipramine, and ketoconazole, which actually induced this phenotype. Principal component analysis (PCA) using these probes clearly separated dose- and time-dependent clusters of treated groups from their controls. Moreover, 6 drugs (chloramphenicol, chlorpromazine, gentamicin, perhexiline, promethazine, and tamoxifen), which were reported to cause phospholipidosis but judged as negative by histopathological examination, were designated as positive by PCA usingmore » these probe sets. Eight drugs (carbon tetrachloride, coumarin, tetracycline, metformin, hydroxyzine, diltiazem, 2-bromoethylamine, and ethionamide), which showed phospholipidosis-like vacuolar formation in the histopathology, could be distinguished from the typical drugs causing phospholipidosis. Moreover, the possible induction of phospholipidosis was predictable by the expression of these genes 24 h after single administration in some of the drugs. We conclude that these identified 78 probe sets could be useful for diagnosis of phospholipidosis, and that toxicogenomics would be a promising approach for prediction of this type of toxicity.« less

Understanding of Relationship between Phospholipid Membrane Permeability and Self-Diffusion Coefficients of Some Drugs and Biologically Active Compounds in Model Solvents.

PubMed

Blokhina, Svetlana V; Volkova, Tatyana V; Golubev, Vasiliy A; Perlovich, German L

2017-10-02

In this work we measured self-diffusion coefficients of 5 drugs (aspirin, caffeine, ethionamide, salicylic acid, and paracetamol) and 11 biologically active compounds of similar structure in deuterated water and 1-octanol by NMR. It has been found that an increase in the van der Waals volume of the molecules of the studied substances result in reduction of their diffusion mobility in both solvents. The analysis of the experimental data showed the influence of chemical nature and structural isomerization of the molecules on the diffusion mobility. Apparent permeability coefficients of the studied compounds were determined using an artificial phospholipid membrane made of egg lecithin as a model of in vivo absorption. Distribution coefficients in 1-octanol/buffer pH 7.4 system were measured. For the first time the model of the passive diffusion through the phospholipid membrane was validated based on the experimental data. To this end, the passive diffusion was considered as an additive process of molecule passage through the aqueous boundary layer before the membrane and 1-octanol barrier simulating the lipid layer of the membrane.

Discovery of novel InhA reductase inhibitors: application of pharmacophore- and shape-based screening approach.

PubMed

Kumar, Uday Chandra; Bvs, Suneel Kumar; Mahmood, Shaik; D, Sriram; Kumar-Sahu, Prashanta; Pulakanam, Sridevi; Ballell, Lluís; Alvarez-Gomez, Daniel; Malik, Siddharth; Jarp, Sarma

2013-03-01

InhA is a promising and attractive target in antimycobacterial drug development. InhA is involved in the reduction of long-chain trans-2-enoyl-ACP in the type II fatty acid biosynthesis pathway of Mycobacterium tuberculosis. Recent studies have demonstrated that InhA is one of the targets for the second line antitubercular drug ethionamide. In the current study, we have generated quantitative pharmacophore models using known InhA inhibitors and validated using a large test set. The validated pharmacophore model was used as a query to screen an in-house database of 400,000 compounds and retrieved 25,000 hits. These hits were further ranked based on its shape and feature similarity with potent InhA inhibitor using rapid overlay of chemical structures (OpenEye™) and subsequent hits were subjected for docking. Based on the pharmacophore, rapid overlay of chemical structures model and docking interactions, 32 compounds with more than eight chemotypes were selected, purchased and assayed for InhA inhibitory activity. Out of the 32 compounds, 28 demonstrated 10-38% inhibition against InhA at 10 µM. Further optimization of these analogues is in progress and will update in due course.

Changing prevalence and resistance patterns in children with drug-resistant tuberculosis in Mumbai.

PubMed

Shah, Ira; Shah, Forum

2017-05-01

The prevalence of drug-resistant (DR) tuberculosis (TB) in children is increasing. Although, in India, multi-drug-resistant (MDR) TB rates have been relatively stable, the number of children with pre-extensively drug-resistant and extensively drug-resistant (XDR) TB is increasing. To determine whether the prevalence of DR TB in children in Mumbai is changing and to study the evolving patterns of resistance. A retrospective study was undertaken in 1311 paediatric patients referred between April 2007 and March 2013 to the Paediatric TB clinic at B. J. Wadia Hospital for Children, Mumbai. Children were defined as having DR TB on the basis of drug susceptibility testing (DST) of Mycobacterium tuberculosis grown on culture of body fluids (in the case of extra pulmonary TB) or from gastric lavage/bronchi-alveolar lavage/sputum in patients with pulmonary TB or from DST of the contacts. The prevalence of DR TB was calculated and the type of DR was evaluated yearly and in the pre-2010 and post-2010 eras. The overall prevalence of DR TB was 86 (6.6%) with an increase from 23 (5.6%) patients pre-2010 to 63 (7%) post-2010 (P = 0.40). Nine (10.4%) patients were diagnosed on the basis of contact with a parent with DR TB. Overall fluoroquinolone resistance increased from 9 (39.1%) pre-2010 to 59 (93.7%) post-2010 (P = 0.0001): moxifloxacin resistance increased from 2 (8.7%) to 29 (46%) (P = 0.0018) and ofloxacin resistance increased from 7 (30.4%) to 30 (47.6%) (P = 0.14). Ethionamide resistance also increased from 6 (26.1%) to 31 (49.2%) (P = 0.04), aminoglycoside resistance was one (4.3%) pre-2010 and 12 (19%) post-2010 (P = 0.17) and resistance remained virtually the same for both amikacin [0 pre-2010 and 6 (9.5%) after 2010] and kanamycin [one (4.3%) pre- and 6 (9.5%) post-2010]. Of the first-line drugs, resistance remained the same for isoniazid [23 (100%) to 61 (96.8%)], rifampicin [22 (95.7%) to 51 (80.9%),P = 0.17], pyrazinamide [15 (65.2%) to 35 (55.6%), P = 0.47], ethambutol [14 (60.9%) to 38 (60.3%), P = 1.00] and streptomycin [19 (82.6%) to 50 (79.4%), P = 1.00]. Resistance to PAS remained unchanged [2 (8.7%) to 5 (7.9%), P = 1.00]. There is increasing resistance to second-line anti-tuberculosis (ATT) drugs, particularly flouroquinolones and ethionamide. Hence, there is an urgent need to avoid the use of ATT drugs for non-tuberculous infection and to increase surveillance for DR TB in adults as MDR TB in children is usually through contact with an adult with infectious MDR TB.

Pattern of secondary acquired drug resistance to antituberculosis drug in Mumbai, India--1991-1995.

PubMed

Chowgule, R V; Deodhar, L

1998-01-01

A retrospective observational study was conducted to find out whether secondary acquired drug resistance to isoniazid and ethambutol is high and to rifamycin and pyrazinamide is low, as is commonly believed in India. There were 2033 patients, whose sputum samples (6099) were reviewed from a specimen registry of the microbiology laboratory for the years 1991 to 1995. Of these, 521 (25.6%) patients [335 males and 186 females; age ranged from 11 to 75 years] had sputum positive culture and sensitivity for acid-fast bacilli (AFB). The drug resistance patterns in our study were: isoniazid (H) 15%, rifamycin (R) 66.8%, pyrazinamide (Z) 72.2%, ethambutol (E) 8.4%, streptomycin (S) 53.6%, cycloserine (C) 39.2% kanamycin (K) 25.1% and ethionamide (Eth) 65.3%. The resistance to streptomycin showed a significant fall over a year while there was a rise in resistance to cycloserine and kanamycin which is significant. The rate of secondary acquired resistance of isoniazid and ethambutol was low, and the rate of secondary acquired resistance to rifamycin and pyrazinamide was high, which is contarary to the common belief regarding these drugs in India. This implies that isoniazid is still a valuable drug in the treatment of multidrug resistance in India.

The Mycobacterium tuberculosis transcriptional repressor EthR is negatively regulated by Serine/Threonine phosphorylation.

PubMed

Leiba, Jade; Carrère-Kremer, Séverine; Blondiaux, Nicolas; Dimala, Martin Moune; Wohlkönig, Alexandre; Baulard, Alain; Kremer, Laurent; Molle, Virginie

2014-04-18

Recent efforts have underlined the role of Serine/Threonine Protein Kinases (STPKs) in growth, pathogenesis and cell wall metabolism in mycobacteria. Herein, we demonstrated that the Mycobacterium tuberculosis EthR, a transcriptional repressor that regulates the activation process of the antitubercular drug ethionamide (ETH) is a specific substrate of the mycobacterial kinase PknF. ETH is a prodrug that must undergo bioactivation by the monooxygenease EthA to exert its antimycobacterial activity and previous studies reported that EthR represses transcription of ethA by binding to the ethA-ethR intergenic region. Mass spectrometry analyses and site-directed mutagenesis identified a set of four phosphoacceptors, namely Thr2, Thr3, Ser4 and Ser7. This was further supported by the complete loss of PknF-dependent phosphorylation of a phosphoablative EthR mutant protein. Importantly, a phosphomimetic version of EthR, in which all phosphosites were replaced by Asp residues, exhibited markedly decreased DNA-binding activity compared with the wild-type protein. Together, these findings are the first demonstration of EthR phosphorylation and indicate that phosphorylation negatively affects its DNA-binding activity, which may impact ETH resistance levels in M. tb. Copyright © 2014 Elsevier Inc. All rights reserved.

PROPOSAL OF ANTI-TUBERCULOSIS REGIMENS BASED ON SUSCEPTIBILITY TO ISONIAZID AND RIFAMPICIN

PubMed Central

Mendoza-Ticona, Alberto; Moore, David AJ; Alarcón, Valentina; Samalvides, Frine; Seas, Carlos

2014-01-01

Objective To elaborate optimal anti-tuberculosis regimens following drug susceptibility testing (DST) to isoniazid (H) and rifampicin (R). Design 12 311 M. tuberculosis strains (National Health Institute of Peru 2007-2009) were classified in four groups according H and R resistance. In each group the sensitivity to ethambutol (E), pirazinamide (Z), streptomycin (S), kanamycin (Km), capreomycin (Cm), ciprofloxacin (Cfx), ethionamide (Eto), cicloserine (Cs) and p-amino salicilic acid (PAS) was determined. Based on resistance profiles, domestic costs, and following WHO guidelines, we elaborated and selected optimal putative regimens for each group. The potential efficacy (PE) variable was defined as the proportion of strains sensitive to at least three or four drugs for each regimen evaluated. Results Selected regimes with the lowest cost, and highest PE of containing 3 and 4 effective drugs for TB sensitive to H and R were: HRZ (99,5%) and HREZ (99,1%), respectively; RZECfx (PE=98,9%) and RZECfxKm (PE=97,7%) for TB resistant to H; HZECfx (96,8%) and HZECfxKm (95,4%) for TB resistant to R; and EZCfxKmEtoCs (82.9%) for MDR-TB. Conclusion Based on resistance to H and R it was possible to select anti-tuberculosis regimens with high probability of success. This proposal is a feasible alternative to tackle tuberculosis in Peru where the access to rapid DST to H and R is improving progressively. PMID:23949502

Survey of tuberculosis drug resistance among Tibetan refugees in India.

PubMed

Salvo, F; Dorjee, K; Dierberg, K; Cronin, W; Sadutshang, T D; Migliori, G B; Rodrigues, C; Trentini, F; Di Serio, C; Chaisson, R; Cirillo, D M

2014-06-01

Tuberculosis (TB) is a major health problem among Tibetans living in exile in India. Although drug-resistant TB is considered common in clinical practice, precise data are lacking. To determine the proportion of drug-resistant cases among new and previously treated Tibetan TB patients. In a drug resistance survey in five Tibetan settlements in India, culture and drug susceptibility testing (DST) for first-line drugs were performed among all consecutive new and previously treated TB cases from April 2010 to September 2011. DST against kanamycin (KM), ethionamide, para-aminosalicylic acid and ofloxacin (OFX) was performed on multidrug-resistant TB (MDR-TB) isolates. Of 307 patients enrolled in the study, 264 (193 new and 71 previously treated) were culture-positive and had DST available. All patients tested for the human immunodeficiency virus (n = 250) were negative. Among new TB cases, 14.5% had MDR-TB and 5.7% were isoniazid (INH) monoresistant. Among previously treated cases, 31.4% had MDR-TB and 12.7% were INH-monoresistant. Of the MDR-TB isolates, 28.6% of new and 26.1% of previously treated cases were OFX-resistant, while 7.1% of new cases and 8.7% of previously treated cases were KM-resistant. Three patients had extensively drug-resistant TB. MDR-TB is common in new and previously treated Tibetans in India, who also show additional complex resistance patterns. Of particular concern is the high percentage of MDR-TB strains resistant to OFX, KM or both.

A population-based study of first and second-line drug-resistant tuberculosis in a high-burden area of the Mexico/United States border.

PubMed

Becerril-Montes, Pola; Said-Fernández, Salvador; Luna-Herrera, Julieta; Caballero-Olín, Guillermo; Enciso-Moreno, José Antonio; Martínez-Rodríguez, Herminia Guadalupe; Padilla-Rivas, Gerardo; Nancy-Garza-Treviño, Elsa; Molina-Salinas, Gloria María

2013-04-01

The resistance of 139 Mycobacterium tuberculosis (MTB) isolates from the city of Monterrey, Northeast Mexico, to first and second-line anti-TB drugs was analysed. A total of 73 isolates were susceptible and 66 were resistant to anti-TB drugs. Monoresistance to streptomycin, isoniazid (INH) and ethambutol was observed in 29 cases. Resistance to INH was found in 52 cases and in 29 cases INH resistance was combined with resistance to two or three drugs. A total of 24 isolates were multidrug-resistant (MDR) resistant to at least INH and rifampicin and 11 MDR cases were resistant to five drugs. The proportion of MDR-TB among new TB cases in our target population was 0.72% (1/139 cases). The proportion of MDR-TB among previously treated cases was 25.18% (35/139 cases). The 13 polyresistant and 24 MDR isolates were assayed against the following seven second-line drugs: amikacin (AMK), kanamycin (KAN), capreomycin (CAP), clofazimine (CLF), ethionamide (ETH), ofloxacin (OFL) and cycloserine (CLS). Resistance to CLF, OFL or CLS was not observed. Resistance was detected to ETH (10.80%) and to AMK (2.70%), KAN (2.70%) and CAP (2.70%). One isolate of MDR with primary resistance was also resistant to three second-line drugs. Monterrey has a high prevalence of MDR-TB among previously treated cases and extensively drug-resistant-MTB strains may soon appear.

A population-based study of first and second-line drug-resistant tuberculosis in a high-burden area of the Mexico/United States border

PubMed Central

Becerril-Montes, Pola; Said-Fernández, Salvador; Luna-Herrera, Julieta; Caballero-Olín, Guillermo; Enciso-Moreno, José Antonio; Martínez-Rodríguez, Herminia Guadalupe; Padilla-Rivas, Gerardo; Nancy-Garza-Treviño, Elsa; Molina-Salinas, Gloria María

2013-01-01

The resistance of 139 Mycobacterium tuberculosis (MTB) isolates from the city of Monterrey, Northeast Mexico, to first and second-line anti-TB drugs was analysed. A total of 73 isolates were susceptible and 66 were resistant to anti-TB drugs. Monoresistance to streptomycin, isoniazid (INH) and ethambutol was observed in 29 cases. Resistance to INH was found in 52 cases and in 29 cases INH resistance was combined with resistance to two or three drugs. A total of 24 isolates were multidrug-resistant (MDR) resistant to at least INH and rifampicin and 11 MDR cases were resistant to five drugs. The proportion of MDR-TB among new TB cases in our target population was 0.72% (1/139 cases). The proportion of MDR-TB among previously treated cases was 25.18% (35/139 cases). The 13 polyresistant and 24 MDR isolates were assayed against the following seven second-line drugs: amikacin (AMK), kanamycin (KAN), capreomycin (CAP), clofazimine (CLF), ethionamide (ETH), ofloxacin (OFL) and cycloserine (CLS). Resistance to CLF, OFL or CLS was not observed. Resistance was detected to ETH (10.80%) and to AMK (2.70%), KAN (2.70%) and CAP (2.70%). One isolate of MDR with primary resistance was also resistant to three second-line drugs. Monterrey has a high prevalence of MDR-TB among previously treated cases and extensively drug-resistant-MTB strains may soon appear. PMID:23579794

EthA, a Common Activator of Thiocarbamide-Containing Drugs Acting on Different Mycobacterial Targets▿

PubMed Central

Dover, Lynn G.; Alahari, Anuradha; Gratraud, Paul; Gomes, Jessica M.; Bhowruth, Veemal; Reynolds, Robert C.; Besra, Gurdyal S.; Kremer, Laurent

2007-01-01

Many of the current antimycobacterial agents require some form of cellular activation unmasking reactive groups, which in turn will bind to their specific targets. Therefore, understanding the mechanisms of activation of current antimycobacterials not only helps to decipher mechanisms of drug resistance but may also facilitate the development of alternative activation strategies or of analogues that do not require such processes. Herein, through the use of genetically defined strains of Mycobacterium bovis BCG we provide evidence that EthA, previously shown to activate ethionamide, also converts isoxyl (ISO) and thiacetazone (TAC) into reactive species. These results were further supported by the development of an in vitro assay using purified recombinant EthA, which allowed direct assessment of the metabolism of ISO. Interestingly, biochemical analysis of [14C]acetate-labeled cultures suggested that all of these EthA-activated drugs inhibit mycolic acid biosynthesis via different mechanisms through binding to specific targets. This report is also the first description of the molecular mechanism of action of TAC, a thiosemicarbazone antimicrobial agent that is still used in the treatment of tuberculosis as a second-line drug in many developing countries. Altogether, the results suggest that EthA is a common activator of thiocarbamide-containing drugs. The broad specificity of EthA can now be used to improve the activation process of these drugs, which may help overcome the toxicity problems associated with clinical thiocarbamide use. PMID:17220416

[The Spectrum of Mutations in Genes Associated with Resistance to Rifampicin, Isoniazid, and Fluoroquinolones in the Clinical Strains of M. tuberculosis Reflects the Transmissibility of Mutant Clones].

PubMed

Ergeshov, A; Andreevskaya, S N; Larionova, E E; Smirnova, T G; Chernousova, L N

2017-01-01

To study the transmissibility of drug resistant mutant clones, M. tuberculosis samples were isolated from the patients of the clinical department and the polyclinic of the Central TB Research Institute (n = 1455) for 2011-2014. A number of clones were phenotypically resistant to rifampicin (n = 829), isoniazid (n = 968), and fluoroquinolones (n = 220). We have detected 21 resistance-associated variants in eight codons of rpoB, six variants in three codons of katG, three variants in two positions of inhA, four variants in four positions of ahpC, and nine variants in five codons of gyrA, which were represented in the analyzed samples with varied frequencies. Most common mutations were rpoB 531 Ser→Leu (77.93%), katG 315 (Ser→Thr) (94.11%), and gyrA 94 (Asp→Gly) (45.45%). We found that the mutations at position 15 of inhA (C→T) (frequency of 25.72%) are commonly associated with katG 315 (Ser→Thr). This association of two DNA variants may arise due to the double selection by coexposure of M. tuberculosis to isoniazid and ethionamide. The high transmissibility of mutated strains was observed, which may be explained by the minimal influence of the resistance determinants on strain viability. The high transmissibility of resistant variants may also explain the large populational prevalence of drug-resistant TB strains.

Increasing Prevalence of Pediatric Drug-Resistant Tuberculosis in Mumbai, India and its Outcome.

PubMed

Shah, Miti A; Shah, Ira

2018-03-24

B.J.Wadia Hospital,Mumbai OBJECTIVE:: The prevalence and type of DR-TB was evaluated pre and post-2013 and outcome was studied. Descriptive retrospective study. Children were defined as having DR-TB on the basis of GeneXpert or LPA and/or drug susceptibility testing(DST) of MTB grown on culture or from contact's DST. The prevalence of DR-TB was 110 out of 1145 cases (9.6%) which showed an increase, compared to 5.6% pre-2010 and 7% in 2010-2013(p=0.014408). Twenty-two (20%) children had pulmonary-TB(PTB) and 88(80%) had extra-pulmonary-TB(EPTB) with disseminated-TB being the most common presentation in 31 children (28.18%). Ninety-six (87.3%) children were bacteriologically confirmed TB cases and 14 (12.7%) were clinically diagnosed-TB and treated as per contact DST. Eight (7.2%) cases were monoresistant, 7 (6.3%) polyresistant, MDR-TB seen in 28 (25.45%) patients, 32 (29.09%) had pre-XDR-TB, 9 (8.18%) had XDR-TB and 12 (10.9%) were rifampicin resistant. Ethionamide resistance increased from 26.1% pre-2013 to 60.8% post-2013(p=0.014408) and ofloxacin resistance rose from 30.4% pre-2010, to 47.6% in 2010-2013 and 56.9% post-2013(p=0.080863). Moxifloxacin resistance showed an acute rise from 8.7% pre-2010, to 46% in 2010-2013 and 57% post-2013(p=0.000275). Thirty-three (30%) patients had completed their treatment, 21(19.09%) were lost to follow up and 56(50.09%) patients are still on treatment.

Escherichia coli Overexpressing a Baeyer-Villiger Monooxygenase from Acinetobacter radioresistens Becomes Resistant to Imipenem

PubMed Central

Minerdi, Daniela; Zgrablic, Ivan; Castrignanò, Silvia; Catucci, Gianluca; Medana, Claudio; Terlizzi, Maria Elena; Gribaudo, Giorgio; Gilardi, Gianfranco

2015-01-01

Antimicrobial resistance is a global issue currently resulting in the deaths of hundreds of thousands of people a year worldwide. Data present in the literature illustrate the emergence of many bacterial species that display resistance to known antibiotics; Acinetobacter spp. are a good example of this. We report here that Acinetobacter radioresistens has a Baeyer-Villiger monooxygenase (Ar-BVMO) with 100% amino acid sequence identity to the ethionamide monooxygenase of multidrug-resistant (MDR) Acinetobacter baumannii. Both enzymes are only distantly phylogenetically related to other canonical bacterial BVMO proteins. Ar-BVMO not only is capable of oxidizing two anticancer drugs metabolized by human FMO3, danusertib and tozasertib, but also can oxidize other synthetic drugs, such as imipenem. The latter is a member of the carbapenems, a clinically important antibiotic family used in the treatment of MDR bacterial infections. Susceptibility tests performed by the Kirby-Bauer disk diffusion method demonstrate that imipenem-sensitive Escherichia coli BL21 cells overexpressing Ar-BVMO become resistant to this antibiotic. An agar disk diffusion assay proved that when imipenem reacts with Ar-BVMO, it loses its antibiotic property. Moreover, an NADPH consumption assay with the purified Ar-BVMO demonstrates that this antibiotic is indeed a substrate, and its product is identified by liquid chromatography-mass spectrometry to be a Baeyer-Villiger (BV) oxidation product of the carbonyl moiety of the β-lactam ring. This is the first report of an antibiotic-inactivating BVMO enzyme that, while mediating its usual BV oxidation, also operates by an unprecedented mechanism of carbapenem resistance. PMID:26459905

Escherichia coli Overexpressing a Baeyer-Villiger Monooxygenase from Acinetobacter radioresistens Becomes Resistant to Imipenem.

PubMed

Minerdi, Daniela; Zgrablic, Ivan; Castrignanò, Silvia; Catucci, Gianluca; Medana, Claudio; Terlizzi, Maria Elena; Gribaudo, Giorgio; Gilardi, Gianfranco; Sadeghi, Sheila J

2016-01-01

Antimicrobial resistance is a global issue currently resulting in the deaths of hundreds of thousands of people a year worldwide. Data present in the literature illustrate the emergence of many bacterial species that display resistance to known antibiotics; Acinetobacter spp. are a good example of this. We report here that Acinetobacter radioresistens has a Baeyer-Villiger monooxygenase (Ar-BVMO) with 100% amino acid sequence identity to the ethionamide monooxygenase of multidrug-resistant (MDR) Acinetobacter baumannii. Both enzymes are only distantly phylogenetically related to other canonical bacterial BVMO proteins. Ar-BVMO not only is capable of oxidizing two anticancer drugs metabolized by human FMO3, danusertib and tozasertib, but also can oxidize other synthetic drugs, such as imipenem. The latter is a member of the carbapenems, a clinically important antibiotic family used in the treatment of MDR bacterial infections. Susceptibility tests performed by the Kirby-Bauer disk diffusion method demonstrate that imipenem-sensitive Escherichia coli BL21 cells overexpressing Ar-BVMO become resistant to this antibiotic. An agar disk diffusion assay proved that when imipenem reacts with Ar-BVMO, it loses its antibiotic property. Moreover, an NADPH consumption assay with the purified Ar-BVMO demonstrates that this antibiotic is indeed a substrate, and its product is identified by liquid chromatography-mass spectrometry to be a Baeyer-Villiger (BV) oxidation product of the carbonyl moiety of the β-lactam ring. This is the first report of an antibiotic-inactivating BVMO enzyme that, while mediating its usual BV oxidation, also operates by an unprecedented mechanism of carbapenem resistance. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Antimicrobial susceptibility testing of Mycobacterium tuberculosis complex for first and second line drugs by broth dilution in a microtiter plate format.

PubMed

Hall, Leslie; Jude, Kurt P; Clark, Shirley L; Wengenack, Nancy L

2011-06-24

The rapid detection of antimicrobial resistance is important in the effort to control the increase in resistant Mycobacterium tuberculosis (Mtb). Antimicrobial susceptibility testing (AST) of Mtb has traditionally been performed by the agar method of proportion or by macrobroth testing on an instrument such as the BACTEC (Becton Dickinson, Sparks, MD), VersaTREK (TREK Diagnostics, Cleveland, OH) or BacT/ALERT (bioMérieux, Hazelwood, MO). The agar proportion method, while considered the "gold" standard of AST, is labor intensive and requires calculation of resistance by performing colony counts on drug-containing agar as compared to drug-free agar. If there is ≥1% growth on the drug-containing medium as compared to drug-free medium, the organism is considered resistant to that drug. The macrobroth methods require instrumentation and test break point ("critical") drug concentrations for the first line drugs (isoniazid, ethambutol, rifampin, and pyrazinamide). The method described here is commercially available in a 96 well microtiter plate format [MYCOTB (TREK Diagnostics)] and contains increasing concentrations of 12 antimicrobials used for treatment of tuberculosis including both first (isoniazid, rifampin, ethambutol) and second line drugs (amikacin, cycloserine, ethionamide, kanamycin, moxifloxacin, ofloxacin, para-aminosalicylic acid, rifabutin, and streptomycin). Pyrazinamide, a first line drug, is not included in the microtiter plate due to its need for acidic test conditions. Advantages of the microtiter system include both ease of set up and faster turn around time (14 days) compared with traditional agar proportion (21 days). In addition, the plate can be set up from inoculum prepared using either broth or solid medium. Since the microtiter plate format is new and since Mtb presents unique safety challenges in the laboratory, this protocol will describe how to safely setup, incubate and read the microtiter plate.

Molecular Characterization of Isoniazid-Resistant Mycobacterium tuberculosis Isolates Collected in Australia

PubMed Central

Lavender, Caroline; Globan, Maria; Sievers, Aina; Billman-Jacobe, Helen; Fyfe, Janet

2005-01-01

Elucidation of the molecular basis of isoniazid (INH) resistance in Mycobacterium tuberculosis has led to the development of different genotypic approaches for the rapid detection of INH resistance in clinical isolates. Mutations in katG, in particular the S315T substitution, are responsible for INH resistance in a large proportion of tuberculosis cases. However, the frequency of the katG S315T substitution varies with population samples. In this study, 52 epidemiologically unrelated clinical INH-resistant M. tuberculosis isolates collected in Australia were screened for mutations at katG codon 315 and the fabG1-inhA regulatory region. Importantly, 52 INH-sensitive isolates, selected to reflect the geographic and genotypic diversity of the isolates, were also included for comparison. The katG S315T substitution and fabG1-inhA −15 C-to-T mutation were identified in 34 and 13 of the 52 INH-resistant isolates, respectively, and none of the INH-sensitive isolates. Three novel katG mutations, D117A, M257I, and G491C, were identified in three INH-resistant strains with a wild-type katG codon 315, fabG1-inhA regulatory region, and inhA structural gene. When analyzed for possible associations between resistance mechanisms, resistance phenotype, and genotypic groups, it was found that neither the katG S315T nor fabG1-inhA −15 C-to-T mutation clustered with any one genotypic group, but that the −15 C-to-T substitution was associated with isolates with intermediate INH resistance and isolates coresistant to ethionamide. In total, 90.4% of unrelated INH-resistant isolates could be identified by analysis of just two loci: katG315 and the fabG1-inhA regulatory region. PMID:16189082

Revisiting susceptibility testing in MDR-TB by a standardized quantitative phenotypic assessment in a European multicentre study.

PubMed

Cambau, E; Viveiros, M; Machado, D; Raskine, L; Ritter, C; Tortoli, E; Matthys, V; Hoffner, S; Richter, E; Perez Del Molino, M L; Cirillo, D M; van Soolingen, D; Böttger, E C

2015-03-01

Treatment outcome of MDR-TB is critically dependent on the proper use of second-line drugs as per the result of in vitro drug susceptibility testing (DST). We aimed to establish a standardized DST procedure based on quantitative determination of drug resistance and compared the results with those of genotypes associated with drug resistance. The protocol, based on MGIT 960 and the TB eXiST software, was evaluated in nine European reference laboratories. Resistance detection at a screening drug concentration was followed by determination of resistance levels and estimation of the resistance proportion. Mutations in 14 gene regions were investigated using established techniques. A total of 139 Mycobacterium tuberculosis isolates from patients with MDR-TB and resistance beyond MDR-TB were tested for 13 antituberculous drugs: isoniazid, rifampicin, rifabutin, ethambutol, pyrazinamide, streptomycin, para-aminosalicylic acid, ethionamide, amikacin, capreomycin, ofloxacin, moxifloxacin and linezolid. Concordance between phenotypic and genotypic resistance was >80%, except for ethambutol. Time to results was short (median 10 days). High-level resistance, which precludes the therapeutic use of an antituberculous drug, was observed in 49% of the isolates. The finding of a low or intermediate resistance level in 16% and 35% of the isolates, respectively, may help in designing an efficient personalized regimen for the treatment of MDR-TB patients. The automated DST procedure permits accurate and rapid quantitative resistance profiling of first- and second-line antituberculous drugs. Prospective validation is warranted to determine the impact on patient care. © The Author 2014. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Preparation, characterization, drug release and computational modelling studies of antibiotics loaded amorphous chitin nanoparticles.

PubMed

Gayathri, N K; Aparna, V; Maya, S; Biswas, Raja; Jayakumar, R; Mohan, C Gopi

2017-12-01

We present a computational investigation of binding affinity of different types of drugs with chitin nanocarriers. Understanding the chitn polymer-drug interaction is important to design and optimize the chitin based drug delivery systems. The binding affinity of three different types of anti-bacterial drugs Ethionamide (ETA) Methacycline (MET) and Rifampicin (RIF) with amorphous chitin nanoparticles (AC-NPs) were studied by integrating computational and experimental techniques. The binding energies (BE) of hydrophobic ETA, hydrophilic MET and hydrophobic RIF were -7.3kcal/mol, -5.1kcal/mol and -8.1kcal/mol respectively, with respect to AC-NPs, using molecular docking studies. This theoretical result was in good correlation with the experimental studies of AC-drug loading and drug entrapment efficiencies of MET (3.5±0.1 and 25± 2%), ETA (5.6±0.02 and 45±4%) and RIF (8.9±0.20 and 53±5%) drugs respectively. Stability studies of the drug encapsulated nanoparticles showed stable values of size, zeta and polydispersity index at 6°C temperature. The correlation between computational BE and experimental drug entrapment efficiencies of RIF, ETA and MET drugs with four AC-NPs strands were 0.999 respectively, while that of the drug loading efficiencies were 0.854 respectively. Further, the molecular docking results predict the atomic level details derived from the electrostatic, hydrogen bonding and hydrophobic interactions of the drug and nanoparticle for its encapsulation and loading in the chitin-based host-guest nanosystems. The present results thus revealed the drug loading and drug delivery insights and has the potential of reducing the time and cost of processing new antibiotic drug delivery nanosystem optimization, development and discovery. Copyright © 2017 Elsevier Ltd. All rights reserved.

Pharmacokinetics and relative bioavailability of clofazimine in relation to food, orange juice and antacid.

PubMed

Nix, D E David E; Adam, R D Rodney D; Auclair, Barbara; Krueger, T S Todd S; Godo, P G Paul G; Peloquin, C A Charles A

2004-01-01

Clofazimine is potentially useful for the treatment of disease due to multidrug resistant Mycobacterium tuberculosis, as well as leprosy and certain chronic skin diseases. Its pharmacokinetics have been incompletely characterized. This study was conducted to explore issues relating to bioavailability in the presence of food, orange juice, and antacid. A 5 drug regimen consisting of clofazimine, cycloserine, ethionamide, para-aminosalicyclic acid, and pyridoxime was administered to healthy subjects four times using a four period cross-over design with two weeks washout between treatments. Subjects also received orange juice, a high fat meal, aluminum/magnesium antacid, or only water in random order with the drug regimen. The pharmacokinetics of clofazimine were assessed using individual- and population-based methods and relative bioavailability compared to fasting administration was determined. Clofazimine exhibited a sometimes prolonged and variable lag-time and considerable variability in plasma concentrations. From the population analysis (one-compartment model), the mean oral clearance was 76.7 l/h (CV=74.2%) and mean apparent volume of distribution was 1470 l (CV=36.3%). The first-order absorption rate constant ranged from 0.716 to 1.33 h(-1) (pooled CV=61.7%). Residual (proportional) error was 49.1%. Estimates of bioavailability compared to fasting administration were 145% (90% CI, 107-183%) for administration with high fat food, 82.0% (63.2-101%) for administration with orange juice, and 78.5% (55.1-102%) for administration with antacid. Administration of clofazimine with a high fat meal provides the greatest bioavailability, however, bioavailability is associated with high inter- and intra-subject variability. Both orange juice and aluminum-magnesium antacid produced a reduction in mean bioavailability of clofazimine.

Rapid detection of in vitro antituberculous drug resistance among smear-positive respiratory samples using microcolony detection-based direct drug susceptibility testing method.

PubMed

Iftikhar, Irim; Irfan, Seema; Farooqi, Joveria; Azizullah, Zahida; Hasan, Rumina

2017-01-01

With the rise in multidrug-resistant tuberculosis, there is a search for newer techniques that will rapidly detect drug-resistant Mycobacterium tuberculosis. Although molecular techniques can detect resistance, culture is still considered gold standard, especially in resource-limited settings where quick, cheap, and easy techniques are needed. The aim of the study was to evaluate microcolony method thin layer agar (TLA) for quick detection of resistance against the first- and second-line antituberculous drugs in clinical isolates. This was a cross-sectional study performed at Aga Khan University Hospital. A total of 87 Z-N stain smear-positive pulmonary samples were received and indirect drug susceptibility test (ID-DST) was performed using Lowenstein-Jensen and mycobacteria growth indicator tube. Direct DST was performed using TLA on 7H10 agar. TLA was observed twice weekly under microscope for 4 weeks. Sensitivity, specificity, and accuracy were calculated for TLA using indirect susceptibility method as the gold standard. Level of agreement was calculated using Kappa score. TLA showed sensitivity of 89% and 95.2% for isoniazid and rifampicin, while for ethionamide, ofloxacin, and injectable aminoglycosides, it was 96.6%, 92.1%, and 100%, respectively. Specificity for the first-line drugs was >95% while second-line drugs ranged from 70% to 100%. Mean time to positivity was 10.2 days by TLA as compared to 43.1 days by ID-DST. TLA is a quick and reliable method in identifying resistance, especially in resource-limited settings. However, additional liquid culture can be set up as backup, especially in patients on therapy to avoid false negative results.

Delamanid Kills Dormant Mycobacteria In Vitro and in a Guinea Pig Model of Tuberculosis.

PubMed

Chen, Xiuhao; Hashizume, Hiroyuki; Tomishige, Tatsuo; Nakamura, Izuru; Matsuba, Miki; Fujiwara, Mamoru; Kitamoto, Ryuki; Hanaki, Erina; Ohba, Yoshio; Matsumoto, Makoto

2017-06-01

Tuberculosis (TB) treatment is long and requires multiple drugs, likely due to various phenotypes of TB bacilli with variable drug susceptibilities. Drugs with broad activity are urgently needed. This study aimed to evaluate delamanid's activity against growing or dormant bacilli in vitro as well as in vivo Cultures of Mycobacterium bovis BCG Tokyo under aerobic and anaerobic conditions were used to study the activity of delamanid against growing and dormant bacilli, respectively. Delamanid exhibited significant bactericidal activity against replicating and dormant bacilli at or above concentrations of 0.016 and 0.4 mg/liter, respectively. To evaluate delamanid's antituberculosis activity in vivo , we used a guinea pig model of chronic TB infection in which the lung lesions were similar to those in human TB disease. In the guinea pig TB model, a daily dose of 100 mg delamanid/kg of body weight for 4 or 8 weeks demonstrated strong bactericidal activity against Mycobacterium tuberculosis Importantly, histological examination revealed that delamanid killed TB bacilli within hypoxic lesions of the lung. The combination regimens containing delamanid with rifampin and pyrazinamide or delamanid with levofloxacin, ethionamide, pyrazinamide, and amikacin were more effective than the standard regimen (rifampin, isoniazid, and pyrazinamide). Our data show that delamanid is effective in killing both growing and dormant bacilli in vitro and in the guinea pig TB model. Adding delamanid to current TB regimens may improve treatment outcomes, as demonstrated in recent clinical trials with pulmonary multidrug-resistant (MDR) TB patients. Delamanid may be an important drug for consideration in the construction of new regimens to shorten TB treatment duration. Copyright © 2017 American Society for Microbiology.

A 5-year study of patients with pulmonary tuberculosis in a concurrent comparison of home and sanatorium treatment for one year with isoniazid plus PAS*

PubMed Central

Dawson, J. J. Y.; Devadatta, S.; Fox, Wallace; Radhakrishna, S.; Ramakrishnan, C. V.; Somasundaram, P. R.; Stott, H.; Tripathy, S. P.; Velu, S.

1966-01-01

This report from the Tuberculosis Chemotherapy Centre, Madras, summarizes the progress over a 5-year period of 193 patients with newly diagnosed, sputum-positive pulmonary tuberculosis who were admitted to a concurrent comparison of home and sanatorium treatment for one year with isoniazid plus PAS. Previous reports have shown that, despite the traditional advantages of sanatorium treatment—rest, adequate diet, nursing and supervised drug-administration—the home patients responded nearly as well as the sanatorium patients in the first year; further, the relapse rates over a 2-year period of follow-up were similar. The findings in the present report are based on a 4-year period of follow-up and extend these conclusions, the relapse rates over the period being 7% for the home patients and 10% for the sanatorium patients. Patients who failed to respond to treatment in the first year and those who had a bacteriological relapse in the second or subsequent years were usually re-treated with reserve regimens, first with streptomycin plus pyrazinamide and, if this was ineffective, with cycloserine plus ethionamide. Considering the findings over the entire 5-year period, five home patients and three sanatorium patients died from non-tuberculous causes. Of the remainder, 5% of the home patients and 6% of the sanatorium patients died of tuberculosis, 4% in each series had bacteriologically active disease at five years and 90% and 89%, respectively, had bacteriologically quiescent disease at that time. These findings are very encouraging, particularly for developing countries such as India, where tuberculosis is a major problem and sanatorium beds are very few. PMID:5296380

[Molecular epidemiologic study on Mycobacterium tuberculosis from drug resistance monitoring sites of Guangdong Province, 2015].

PubMed

Huang, X C; Guo, H X; Wu, Z H; Guo, C X; Wei, W J; Li, H C; Sun, Q; Zhang, C C; Li, Z Y; Chen, T; Zhong, Q; Zhou, L

2017-05-12

Objective: To understand the characteristics of Mycobacterium tuberculosis (MTB) in epidemiology and distribution from Guangdong Province, and to explore the risk factors associated with drug resistance. Methods: A total of 225 clinical strains of MTB collected from 5 drug resistance monitoring sites of Guangdong Province in 2015 were tested by Regions of Difference 105 (RD105) deletion test and 15 loci mycobacterial interspersed repetitive units (MIRU) were used for genotyping. Gene clustering was analyzed using BioNumerics7.6. Drug susceptibility test was tested by proportion method. The statistical analysis used chi-square test and multivariate logistic regression. Results: There were 158 (70.2%) Beijing family strains from the 225 cases. Hunter-gaston index of MIRU loci varied from each other. The MTBs from Guangdong Province were categorized into 2 gene clusters by clustering analysis in which the rate of cluster of complexⅠwas significantly higher than complexⅡ(χ(2) values were 9.331, P values were 0.020). It was found by multivariate logistic regression that Qub11b was associated with resistance to rifampicin and isoniazid ( P values were 0.013, 0.012 respectively.), ETR F with resistance to isoniazid, streptomycin, ethambutol and ofloxacin ( P values were 0.039, 0.040, 0.023 and 0.003 respectively), Mtub21 with resistance to capreomycin ( P values were 0.040), and QUB26 with resistance to ethionamide ( P values were 0.047). Conclusions: The genes of MTB from Guangdong Province were of polymorphisms and the distribution of strains were stable. QUB11b, ETR F, Mtub21 and QUB26 could be related to biomarkers for predicting drug resistance.

Feasibility and cost-effectiveness of standardised second-line drug treatment for chronic tuberculosis patients: a national cohort study in Peru.

PubMed

Suárez, Pedro G; Floyd, Katherine; Portocarrero, Jaime; Alarcón, Edith; Rapiti, Elisabetta; Ramos, Gilbert; Bonilla, Cesar; Sabogal, Ivan; Aranda, Isabel; Dye, Christopher; Raviglione, Mario; Espinal, Marcos A

2002-06-08

There are no data on the feasibility and cost-effectiveness of using second-line drugs to treat patients with chronic tuberculosis, many of whom are infected with multidrug resistant (MDR) strains of Mycobacterium tuberculosis, in low or middle-income countries. A national programme to treat chronic tuberculosis patients with a directly observed standardised 18-month daily regimen, consisting of kanamycin (3 months only), ciprofloxacin, ethionamide, pyrazinamide, and ethambutol, was established in Peru in 1997. Compliance and treatment outcomes were analysed for the cohort started on treatment between October, 1997, and March, 1999. Total and average costs were assessed. Cost-effectiveness was estimated as the cost per DALY gained. 466 patients were enrolled; 344 were tested for drug susceptibility and 298 (87%) had MDR tuberculosis. 225 patients (48%) were cured, 57 (12%) died, 131 (28%) did not respond to treatment, and 53 (11%) defaulted. Of the 413 (89%) patients who complied with treatment, 225 (55%) were cured. Among MDR patients, resistance to five or more drugs was significantly associated with an unfavourable outcome (death, non-response to treatment, or default; odds ratio 3.37, 95% CI 1.32-8.60; p=0.01). The programme cost US $0.6 million per year, 8% of the National Tuberculosis Programme budget, and US $2381 per patient for those who completed treatment. The mean cost per DALY gained was $211 ($165 at drug prices projected for 2002). Treating chronic tuberculosis patients with high levels of MDR with second-line drugs can be feasible and cost-effective in middle-income countries, provided a strong tuberculosis control programme is in place.

Artificial Intelligence and Amikacin Exposures Predictive of Outcomes in Multidrug-Resistant Tuberculosis Patients.

PubMed

Modongo, Chawangwa; Pasipanodya, Jotam G; Magazi, Beki T; Srivastava, Shashikant; Zetola, Nicola M; Williams, Scott M; Sirugo, Giorgio; Gumbo, Tawanda

2016-10-01

Aminoglycosides such as amikacin continue to be part of the backbone of treatment of multidrug-resistant tuberculosis (MDR-TB). We measured amikacin concentrations in 28 MDR-TB patients in Botswana receiving amikacin therapy together with oral levofloxacin, ethionamide, cycloserine, and pyrazinamide and calculated areas under the concentration-time curves from 0 to 24 h (AUC0-24). The patients were followed monthly for sputum culture conversion based on liquid cultures. The median duration of amikacin therapy was 184 (range, 28 to 866) days, at a median dose of 17.30 (range 11.11 to 19.23) mg/kg. Only 11 (39%) patients had sputum culture conversion during treatment; the rest failed. We utilized classification and regression tree analyses (CART) to examine all potential predictors of failure, including clinical and demographic features, comorbidities, and amikacin peak concentrations (Cmax), AUC0-24, and trough concentrations. The primary node for failure had two competing variables, Cmax of <67 mg/liter and AUC0-24 of <568.30 mg · h/L; weight of >41 kg was a secondary node with a score of 35% relative to the primary node. The area under the receiver operating characteristic curve for the CART model was an R(2) = 0.90 on posttest. In patients weighing >41 kg, sputum conversion was 3/3 (100%) in those with an amikacin Cmax of ≥67 mg/liter versus 3/15 (20%) in those with a Cmax of <67 mg/liter (relative risk [RR] = 5.00; 95% confidence interval [CI], 1.82 to 13.76). In all patients who had both amikacin Cmax and AUC0-24 below the threshold, 7/7 (100%) failed, compared to 7/15 (47%) of those who had these parameters above threshold (RR = 2.14; 95% CI, 1.25 to 43.68). These amikacin dose-schedule patterns and exposures are virtually the same as those identified in the hollow-fiber system model. Copyright © 2016 Modongo et al.

A 5-year study of patients with pulmonary tuberculosis treated at home in a controlled comparison of isoniazid plus PAS with 3 regimens of isoniazid alone*

PubMed Central

Evans, C.; Devadatta, S.; Fox, Wallace; Gangadharam, P. R. J.; Menon, N. K.; Ramakrishnan, C. V.; Sivasubramanian, S.; Somasundaram, P. R.; Stott, H.; Velu, S.

1969-01-01

This report from the Tuberculosis Chemotherapy Centre, Madras, describes the progress, over a 5-year period, of 341 patients with newly diagnosed, sputum-positive tuberculosis. All the patients were treated on a domiciliary basis. In the first year, the patients received, on the basis of random allocation, a standard regimen of isoniazid plus PAS or 1 of 3 regimens of isoniazid alone. Previous reports have shown that the response in the first year was substantially superior with the standard regimen, and that the bacteriological relapse rates in the second year were fairly similar for the 4 regimens. The findings in the present report extend the latter conclusion to the end of 5 years. Further, when considered together with the findings in an earlier study, they have shown that isoniazid, given as maintenance chemotherapy in the second year, was highly effective in preventing bacteriological relapse in patients who, at 1 year, had bacteriologically quiescent disease and no residual cavitation; the effect was, however, less marked in patients with residual cavitation at 1 year. Patients who were clear-cut failures of the allocated chemotherapy and those who had a bacteriological relapse in the second or subsequent years were usually re-treated with streptomycin plus PAS or streptomycin plus pyrazinamide, and if this was ineffective, with cycloserine plus thioacetazone or cycloserine plus ethionamide. Considering the findings over the 5-year period for all patients, 16 died from non-tuberculous causes and 1 took his discharge prematurely. Of the remainder, 86% had bacteriologically quiescent disease at 5 years, 6% had bacteriologically active disease and 8% had died of tuberculosis. These findings confirm the value of well-organized domiciliary chemotherapy, which was established by an earlier report from the Centre, and are particularly encouraging for developing countries such as India, where tuberculosis is a major problem and resources are limited. PMID:5309083

Resistance Patterns among Multidrug-Resistant Tuberculosis Patients in Greater Metropolitan Mumbai: Trends over Time

PubMed Central

Dalal, Alpa; Pawaskar, Akshay; Das, Mrinalini; Desai, Ranjan; Prabhudesai, Pralhad; Chhajed, Prashant; Rajan, Sujeet; Reddy, Deepesh; Babu, Sajit; Jayalakshmi, T. K.; Saranchuk, Peter; Rodrigues, Camilla; Isaakidis, Petros

2015-01-01

Background While the high burden of multidrug-resistant tuberculosis (MDR-TB) itself is a matter of great concern, the emergence and rise of advanced forms of drug-resistance such as extensively drug-resistant TB (XDR-TB) and extremely drug-resistant TB (XXDR-TB) is more troubling. The aim of this study was to investigate the trends over time of patterns of drug resistance in a sample of MDR-TB patients in greater metropolitan Mumbai, India. Methods This was a retrospective, observational study of drug susceptibility testing (DST) results among MDR-TB patients from eight health care facilities in greater Mumbai between 2005 and 2013. We classified resistance patterns into four categories: MDR-TB, pre-XDR-TB, XDR-TB and XXDR-TB. Results A total of 340 MDR-TB patients were included in the study. Pre-XDR-TB was the most common form of drug-resistant TB observed overall in this Mumbai population at 56.8% compared to 29.4% for MDR-TB. The proportion of patients with MDR-TB was 39.4% in the period 2005–2007 and 27.8% in 2011–2013, while the proportion of those with XDR-TB and XXDR-TB was changed from 6.1% and 0% respectively to 10.6% and 5.6% during the same time period. During the same periods, the proportions of patients with ofloxacin, moxifloxacin and ethionamide resistance significantly increased from 57.6% to 75.3%, from 60.0% to 69.5% and from 24.2% to 52.5% respectively (p<0.05). Discussion The observed trends in TB drug-resistance patterns in Mumbai highlight the need for individualized drug regimens, designed on the basis of DST results involving first- and second-line anti-TB drugs and treatment history of the patient. A drug-resistant TB case-finding strategy based on molecular techniques that identify only rifampicin resistance will lead to initiation of suboptimal treatment regimens for a significant number of patients, which may in turn contribute to amplification of resistance and transmission of strains with increasingly advanced resistance within the community. PMID:25606853

Resistance patterns among multidrug-resistant tuberculosis patients in greater metropolitan Mumbai: trends over time.

PubMed

Dalal, Alpa; Pawaskar, Akshay; Das, Mrinalini; Desai, Ranjan; Prabhudesai, Pralhad; Chhajed, Prashant; Rajan, Sujeet; Reddy, Deepesh; Babu, Sajit; Jayalakshmi, T K; Saranchuk, Peter; Rodrigues, Camilla; Isaakidis, Petros

2015-01-01

While the high burden of multidrug-resistant tuberculosis (MDR-TB) itself is a matter of great concern, the emergence and rise of advanced forms of drug-resistance such as extensively drug-resistant TB (XDR-TB) and extremely drug-resistant TB (XXDR-TB) is more troubling. The aim of this study was to investigate the trends over time of patterns of drug resistance in a sample of MDR-TB patients in greater metropolitan Mumbai, India. This was a retrospective, observational study of drug susceptibility testing (DST) results among MDR-TB patients from eight health care facilities in greater Mumbai between 2005 and 2013. We classified resistance patterns into four categories: MDR-TB, pre-XDR-TB, XDR-TB and XXDR-TB. A total of 340 MDR-TB patients were included in the study. Pre-XDR-TB was the most common form of drug-resistant TB observed overall in this Mumbai population at 56.8% compared to 29.4% for MDR-TB. The proportion of patients with MDR-TB was 39.4% in the period 2005-2007 and 27.8% in 2011-2013, while the proportion of those with XDR-TB and XXDR-TB was changed from 6.1% and 0% respectively to 10.6% and 5.6% during the same time period. During the same periods, the proportions of patients with ofloxacin, moxifloxacin and ethionamide resistance significantly increased from 57.6% to 75.3%, from 60.0% to 69.5% and from 24.2% to 52.5% respectively (p<0.05). The observed trends in TB drug-resistance patterns in Mumbai highlight the need for individualized drug regimens, designed on the basis of DST results involving first- and second-line anti-TB drugs and treatment history of the patient. A drug-resistant TB case-finding strategy based on molecular techniques that identify only rifampicin resistance will lead to initiation of suboptimal treatment regimens for a significant number of patients, which may in turn contribute to amplification of resistance and transmission of strains with increasingly advanced resistance within the community.

Comparative Genomic Analysis of Two Clonally Related Multidrug Resistant Mycobacterium tuberculosis by Single Molecule Real Time Sequencing.

PubMed

Leung, Kenneth Siu-Sing; Siu, Gilman Kit-Hang; Tam, Kingsley King-Gee; To, Sabrina Wai-Chi; Rajwani, Rahim; Ho, Pak-Leung; Wong, Samson Sai-Yin; Zhao, Wei W; Ma, Oliver Chiu-Kit; Yam, Wing-Cheong

2017-01-01

Background: Multidrug-resistant tuberculosis (MDR-TB) is posing a major threat to global TB control. In this study, we focused on two consecutive MDR-TB isolated from the same patient before and after the initiation of anti-TB treatment. To better understand the genomic characteristics of MDR-TB, Single Molecule Real-Time (SMRT) Sequencing and comparative genomic analyses was performed to identify mutations that contributed to the stepwise development of drug resistance and growth fitness in MDR-TB under in vivo challenge of anti-TB drugs. Result: Both pre-treatment and post-treatment strain demonstrated concordant phenotypic and genotypic susceptibility profiles toward rifampicin, pyrazinamide, streptomycin, fluoroquinolones, aminoglycosides, cycloserine, ethionamide, and para-aminosalicylic acid. However, although both strains carried identical missense mutations at rpoB S531L, inhA C-15T, and embB M306V, MYCOTB Sensititre assay showed that the post-treatment strain had 16-, 8-, and 4-fold elevation in the minimum inhibitory concentrations (MICs) toward rifabutin, isoniazid, and ethambutol respectively. The results have indicated the presence of additional resistant-related mutations governing the stepwise development of MDR-TB. Further comparative genomic analyses have identified three additional polymorphisms between the clinical isolates. These include a single nucleotide deletion at nucleotide position 360 of rv0888 in pre-treatment strain, and a missense mutation at rv3303c ( lpdA) V44I and a 6-bp inframe deletion at codon 67-68 in rv2071c ( cobM) in the post-treatment strain. Multiple sequence alignment showed that these mutations were occurring at highly conserved regions among pathogenic mycobacteria. Using structural-based and sequence-based algorithms, we further predicted that the mutations potentially have deleterious effect on protein function. Conclusion: This is the first study that compared the full genomes of two clonally-related MDR-TB clinical isolates during the course of anti-TB treatment. Our work has demonstrated the robustness of SMRT Sequencing in identifying mutations among MDR-TB clinical isolates. Comparative genome analysis also suggested novel mutations at rv0888, lpdA , and cobM that might explain the difference in antibiotic resistance and growth pattern between the two MDR-TB strains.

Drug susceptibility testing of Mycobacterium Avium subsp. Avium isolates from naturally infected domestic pigeons to avian tuberculosis.

PubMed

Parvandar, Kaveh; Mayahi, Mansour; Mosavari, Nader; Pajoohi, Reza Aref

2016-12-01

Avian tuberculosis is one of the most important infections affecting most species of birds. Several mycobacterial species have been identified causing avian tuberculosis, and the organisms confirmed most frequently are Mycobacterium avium and Mycobacterium genavense. Any species of birds can be infected with M. avium. Generally, domesticated fowl or captive wild birds are affected more frequently than those living in the wild. M. avium can not only infect all species of birds, but can also infect some domesticated mammals to cause disease, usually with localized lesion. In immunocompetent individuals, M. avium complex isolates produce localized soft tissue infections, including chronic pulmonary infections in the elderly and cervical lymphadenitis in children, but rarely any disseminated disease. In patients infected with HIV and AIDS or in other immunocompromised individuals, M. avium complex isolates frequently cause severe systemic infections. The importance of avian tuberculosis and the risk of its zoonotic spread motivated our interest to determine the drug susceptibility testing of M. avium subsp. avium isolates from naturally infected domestic pigeons to avian tuberculosis. Based on their clinical signs, 80 pigeons suspected with avian tuberculosis were subjected to the study. Out of the 51 identified isolates, 20 M. avium subsp. avium were subjected to the test. Drug susceptibly testing was performed according to the guidelines by Centers for Disease Control and Prevention and using proportional method. In the drug susceptibility testing, all isolates were resistant to streptomycin, kanamycin, ethionamide, and thiophene carboxylic acid hydrazide. Additionally, 3, 2, and 1 isolates were susceptible to isoniazid, rifampin, and ethambutol, respectively. To date, no study has documented the drug susceptibility testing of M. avium isolates from infected birds to avian tuberculosis. Pigeons are extensively kept in urban and rural areas for homing and racing purposes; thus, they can infect people and farm animals exposed to their droppings containing pathogenic M. avium, and the severity of drug resistance of these isolates indicate lethality in immunocompromised individuals and incurable lymphadenitis in immunocompetent individuals. We suggest drug susceptibility testing for more nontuberculous mycobateria, particularly M. avium complex isolated from infected birds and humans, as well as molecular basics of drug sensitivity in order to detect resistance genes of pathogenic M. avium subsp. avium. Copyright © 2016.

FIND Tuberculosis Strain Bank: a Resource for Researchers and Developers Working on Tests To Detect Mycobacterium tuberculosis and Related Drug Resistance.

PubMed

Tessema, Belay; Nabeta, Pamela; Valli, Eloise; Albertini, Audrey; Collantes, Jimena; Lan, Nguyen Huu; Romancenco, Elena; Tukavdze, Nestani; Denkinger, Claudia M; Dolinger, David L

2017-04-01

The spread of multidrug-resistant (MDR) tuberculosis (TB) and extensively drug-resistant (XDR) TB hampers global efforts in the fight against tuberculosis. To enhance the development and evaluation of diagnostic tests quickly and efficiently, well-characterized strains and samples from drug-resistant tuberculosis patients are necessary. In this project, the Foundation for Innovative New Diagnostics (FIND) has focused on the collection, characterization, and storage of such well-characterized reference materials and making them available to researchers and developers. The collection is being conducted at multiple centers in Southeast Asia, South America, Eastern Europe, and soon the sub-Saharan Africa regions. Strains are characterized for their phenotypic resistances and MICs to first-line drugs (FLDs) and second-line drugs (SLDs) using the automated MGIT 960 system following validated procedures and WHO criteria. Analysis of resistance-associated mutations is done by whole-genome sequencing (WGS) using the Illumina NextSeq system. Mycobacterial interspersed repetitive-unit-variable-number tandem-repeat analysis and WGS are used to determine strain lineages. All strains are maintained frozen at -80°C ± 10°C as distinct mother and daughter lots. All strains are extensively quality assured. The data presented here represent an analysis of the initial part of the collection. Currently, the bank contains 118 unique strains with extracted genomic DNA and matched sputum, serum, and plasma samples and will be expanded to a minimum of 1,000 unique strains over the next 3 years. Analysis of the current strains by phenotypic resistance testing shows 102 (86.4%), 10 (8.5%), and 6 (5.1%) MDR, XDR, and mono/poly resistant strains, respectively. Two of the strains are resistant to all 11 drugs that were phenotypically tested. WGS mutation analysis revealed FLD resistance-associated mutations in the rpoB , katG , inhA , embB , embA , and pncA genes; SLD resistance in the gyrA , gyrB , rrs , eis , and tlyA genes; and ethionamide resistance in the ethA genes. Most important lineages are represented in the bank, and further collections have been initiated to increase geographic and lineage diversity. The bank provides highly characterized and high-quality strains as a resource for researchers and developers in support of the development and evaluation of new diagnostics and drug resistance detection tools. Copyright © 2017 Tessema et al.

Assessment of a 96-Well Plate Assay of Quantitative Drug Susceptibility Testing for Mycobacterium Tuberculosis Complex in China.

PubMed

Xia, Hui; Zheng, Yang; Zhao, Bing; van den Hof, Susan; Cobelens, Frank; Zhao, YanLin

2017-01-01

To evaluate the performance of the Sensitire MYCOTB MIC Plate (MYCOTB) which could measure the twelve anti-tuberculosis drugs susceptibility on one 96-wells plate. A total of 140 MDR-TB strains and 60 non-MDR strains were sub-cultured and 193 strains were finally tested for drug resistance using MYCOTB and agar proportion method (APM) and another 7 strains failed of subculture. The drugs included ofloxacin (Ofx), moxifloxacin (Mfx), rifampin (RFP), amikacin (Am), rifabutin (Rfb), para-aminosalicylic acid (PAS), ethionamide (Eth), isoniazid (INH), kanamycin (Km), ethambutol (EMB), streptomycin (Sm), and cycloserine(Cs). The categorical agreement, conditional agreement, sensitivity and specificity of MYCOTB were assessed in comparison with APM. For strains with inconsistent results between MYCOTB and APM, the drug resistance related gene fragments were amplified and sequenced: gyrA for Ofx and Mfx; rpoB for RFP and Rfb; embB for EMB; rpsl for Sm; katG and the promoter region of inhA for INH, ethA and the promoter region of inhA for Eth. The sequence results were compared with results of MYCOTB and APM to analyze the consistency between sequence results and MYCOTB or APM. The categorical agreement between two methods for each drug ranged from 88.6% to 100%. It was the lowest for INH (88.6%). The sensitivity and specificity of MYCOTB ranged from 71.4% to 100% and 84.3% to 100%, respectively. The sensitivity was lowest for Cs(71.4%), EMB at 10μg/ml (80.0%) and INH at 10.0μg/ml (84.6%). The specificity was lowest for Rfb (84.3%). Overall discordance between the two phenotypic methods was observed for 96 strains, of which 63 (65.6%) were found susceptible with APM and resistant with MYCOTB and the remaining 33(34.4%) strains were resistant by APM and susceptible with MYCOTB. 34/52 (65.4%) sequenced APM susceptible and MYCOTB resistant(APM-S/MYCOTB-R) strains had mutations or insertions in the amplified regions. 20/30 (66.7%) sequenced APM resistant and MYCOTB susceptible strains had mutations in the sequenced genes. MICs of twenty-nine of these thirty isolates were equal to or within 1 doubling dilution of the critical concentration. MYCOTB had good performance for most of tested drugs and could be used as an alternative to the more labor demanding and longer turnaround time solid culture based DST method for detection of drug susceptibility in China.

Effect of the explicit flexibility of the InhA enzyme from Mycobacterium tuberculosis in molecular docking simulations.

PubMed

Cohen, Elisangela M L; Machado, Karina S; Cohen, Marcelo; de Souza, Osmar Norberto

2011-12-22

Protein/receptor explicit flexibility has recently become an important feature of molecular docking simulations. Taking the flexibility into account brings the docking simulation closer to the receptors' real behaviour in its natural environment. Several approaches have been developed to address this problem. Among them, modelling the full flexibility as an ensemble of snapshots derived from a molecular dynamics simulation (MD) of the receptor has proved very promising. Despite its potential, however, only a few studies have employed this method to probe its effect in molecular docking simulations. We hereby use ensembles of snapshots obtained from three different MD simulations of the InhA enzyme from M. tuberculosis (Mtb), the wild-type (InhA_wt), InhA_I16T, and InhA_I21V mutants to model their explicit flexibility, and to systematically explore their effect in docking simulations with three different InhA inhibitors, namely, ethionamide (ETH), triclosan (TCL), and pentacyano(isoniazid)ferrate(II) (PIF). The use of fully-flexible receptor (FFR) models of InhA_wt, InhA_I16T, and InhA_I21V mutants in docking simulation with the inhibitors ETH, TCL, and PIF revealed significant differences in the way they interact as compared to the rigid, InhA crystal structure (PDB ID: 1ENY). In the latter, only up to five receptor residues interact with the three different ligands. Conversely, in the FFR models this number grows up to an astonishing 80 different residues. The comparison between the rigid crystal structure and the FFR models showed that the inclusion of explicit flexibility, despite the limitations of the FFR models employed in this study, accounts in a substantial manner to the induced fit expected when a protein/receptor and ligand approach each other to interact in the most favourable manner. Protein/receptor explicit flexibility, or FFR models, represented as an ensemble of MD simulation snapshots, can lead to a more realistic representation of the induced fit effect expected in the encounter and proper docking of receptors to ligands. The FFR models of InhA explicitly characterizes the overall movements of the amino acid residues in helices, strands, loops, and turns, allowing the ligand to properly accommodate itself in the receptor's binding site. Utilization of the intrinsic flexibility of Mtb's InhA enzyme and its mutants in virtual screening via molecular docking simulation may provide a novel platform to guide the rational or dynamical-structure-based drug design of novel inhibitors for Mtb's InhA. We have produced a short video sequence of each ligand (ETH, TCL and PIF) docked to the FFR models of InhA_wt. These videos are available at http://www.inf.pucrs.br/~osmarns/LABIO/Videos_Cohen_et_al_19_07_2011.htm.

Prevalence of drug-resistant tuberculosis and imputed burden in South Africa: a national and sub-national cross-sectional survey.

PubMed

Ismail, Nazir Ahmed; Mvusi, Lindiwe; Nanoo, Ananta; Dreyer, Andries; Omar, Shaheed V; Babatunde, Sanni; Molebatsi, Thabo; van der Walt, Martie; Adelekan, Adeboye; Deyde, Varough; Ihekweazu, Chikwe; Madhi, Shabir A

2018-04-20

Globally, per-capita, South Africa reports a disproportionately high number of cases of multidrug-resistant (MDR) tuberculosis and extensively drug-resistant (XDR) tuberculosis. We sought to estimate the prevalence of resistance to tuberculosis drugs in newly diagnosed and retreated patients with tuberculosis provincially and nationally, and compared these with the 2001-02 estimates. A cross-sectional survey was done between June 15, 2012-June 14, 2014, using population proportionate randomised cluster sampling in the nine provinces in South Africa. 343 clusters were included, ranging between 31 and 48 per province. A patient was eligible for inclusion in the survey if he or she presented as a presumptive case during the intake period at a drug resistance survey enrolling facility. Consenting participants (≥18 years old) completed a questionnaire and had a sputum sample tested for resistance to first-line and second-line drugs. Analysis was by logistic regression with robust SEs, inverse probability weighted against routine data, and estimates were derived using a random effects model. 101 422 participants were tested in 2012-14. Nationally, the prevalence of MDR tuberculosis was 2·1% (95% CI 1·5-2·7) among new tuberculosis cases and 4·6% (3·2-6·0) among retreatment cases. The provincial point prevalence of MDR tuberculosis ranged between 1·6% (95% CI 0·9-2·9) and 5·1% (3·7-7·0). Overall, the prevalence of rifampicin-resistant tuberculosis (4·6%, 95% CI 3·5-5·7) was higher than the prevalence of MDR tuberculosis (2·8%, 2·0-3·6; p=0·01). Comparing the current survey with the previous (2001-02) survey, the overall MDR tuberculosis prevalence was 2·8% versus 2·9% and prevalance of rifampicin-resistant tuberculosis was 3·4% versus 1·8%, respectively. The prevalence of isoniazid mono-resistant tuberculosis was above 5% in all provinces. The prevalence of ethionamide and pyrazinamide resistance among MDR tuberculosis cases was 44·7% (95% CI 25·9-63·6) and 59·1% (49·0-69·1), respectively. The prevalence of XDR tuberculosis was 4·9% (95% CI 1·0-8·8). Nationally, the estimated numbers of cases of rifampicin-resistant tuberculosis, MDR tuberculosis, and isoniazid mono-resistant tuberculosis for 2014 were 13 551, 8249, and 17 970, respectively. The overall prevalence of MDR tuberculosis in South Africa in 2012-14 was similar to that in 2001-02; however, prevalence of rifampicin-resistant tuberculosis almost doubled among new cases. Furthermore, the high prevalence of isoniazid mono-resistant tuberculosis, not routinely screened for, and resistance to second-line drugs has implications for empirical management. President's Emergency Plan for AIDS Relief through the Centers for Disease Control and Prevention under the terms of 1U19GH000571. Copyright © 2018 Elsevier Ltd. All rights reserved.