Multidrug-resistant Mycobacterium Tuberculosis Complex Research Articles

Exploration of the diversity of multi-drug resistant Mycobacterium tuberculosis complex in Lagos, Nigeria using WGS: Distribution of lineages, drug resistance patterns and genetic mutations

Multidrug-resistant (MDR) or extensively drug-resistant (XDR) Tuberculosis (TB) is a major challenge to global TB control. Therefore, accurate tracing of in-country MDR-TB transmission are crucial for the development of optimal TB management strategies. This study aimed to investigate the diversity of MTBC in Nigeria. The lineage and drug-resistance patterns of the clinical MTBC isolates of TB patients in Southwestern region of Nigeria were determined using the WGS approach. The phenotypic DST of the isolates was determined for nine anti-TB drugs. The sequencing achieved average genome coverage of 65.99X. The most represented lineages were L4 (n = 52, 83%), L1 (n = 8, 12%), L2 (n = 2, 3%) and L5 (n = 1, 2%), suggesting a diversified MTB population. In term of detection of M/XDR-TB, while mutations in katG and rpoB genes are the strong predictors for the presence of M/XDR-TB, the current study also found the lack of good genetic markers for drug resistance amongst the MTBC in Nigeria which may pose greater problems on local tuberculosis management efforts. This high-resolution molecular epidemiological data provides valuable insights into the mechanistic for M/XDR TB in Lagos, Nigeria.

Strain diversity and gene mutations associated with presumptive multidrug-resistant Mycobacterium tuberculosis complex isolates in Northwest Ethiopia

In this study, we assessed the genetic diversity and gene mutations that confer resistance to rifampicin (RIF), isoniazid (INH), fluoroquinolone (FQ), and second-line injectable (SLI) drugs in RIF-resistant (RR)/multidrug-resistant tuberculosis (MDR-TB) isolates in Northwest Ethiopia. Spoligotyping was used to assign isolates to TB lineages (Ls), and Hain line probe assays were used to detect resistance to RIF, INH, and FQs, and SLIs. Among 130 analyzed strains, 68.5% were RR, and four major Mycobacterium tuberculosis complex lineages (L1, L3, L4, and L7) were identified with a predominance of the Euro-American L4 (72, 54.7%), while L7 genotypes were less common (3, 2.3%). Overall, the L4-T3-ETH (41, 32.0%), L3-CAS1-Delhi (29, 22.7%), and L3-CAS1-Killi (19, 14.8%) families were most common. Line probe analysis showed that among rpoB mutants, 65.2% were S450L, while 87.8% of katG mutants were S315T. Only three isolates showed mutation (c-15t) at the inhA gene, and no double mutation with katG and inhA genes was found. Six strains, two each of L1, L3, and L4, were resistant to FQs, having gyrA mutations (D94G, S91P), of which three isolates had additional resistance to SLI (rrs A1401G or C1402T mutations) including one isolate with low-level kanamycin (KAN) resistance. This study showed a predominance of L4-T3-ETH, L3-CAS1-Delhi, and L3-CAS1-Killi families, with a high rate of rpoB_S450L and katG_S315T mutations and a low proportion of gyrA and rrs mutations. L7 was less frequently observed in this study. Further investigations are, therefore, needed to understand L7 and other lineages with undefined mutations.

Frequency of rpoB, katG, and inhA Gene Polymorphisms Associated with Multidrug-Resistant Mycobacterium tuberculosis Complex Isolates among Ethiopian TB Patients: A Systematic Review.

Tuberculosis (TB) is one of the top 10 causes of mortality and the first killer among infectious diseases of poverty (IDoPs) worldwide. It disproportionately affects on-third of the world's low-income countries including Ethiopia. One of the factors driving the TB epidemic is the global rise of MDR/XDR-TB and their low detection affect the global TB control progress. Recently, the resistance-associated genetic mutations in MTBC known to confer drug resistance have been detected by rapid molecular diagnostic tests and sequencing methods. In this article, the published literature searched by PubMed database from 2010 to 2021 and English language were considered. The aim of this systematic review was to assess the prevalence of the most common rpoB, katG, and inhA gene mutations associated with multidrug resistance in MTBC clinical strains among TB patients in Ethiopia. Though 22 studies met our eligibility criteria, only 6 studies were included in the final analysis. Using the molecular GenoType MTBDRplus and MTBDRsl line probe assay and sequencing procedures, a total of 932 culture-positive MTBC isolates were examined to determine RIF, INH, and MDR-TB resistance patterns along with rpoB, katG, and inhA gene mutation analysis. As a result, among the genotypically tested MTBC isolates, 119 (12.77%), 83 (8.91%), and 73 (7.32%) isolates were INH, RIF, and MDR-TB resistant, respectively. In any RIF-resistant MTBC strains, the most common single point mutations were in codon 531 (S531L) followed by codon 526 (H526Y) of the rpoB gene. Besides, the most common mutations in any INH-resistant MTBC were strains observed at codon 315 (S315T) and WT probe in the katG gene and at codon C15T and WT1 probe in the inhA promoter region. Detection of resistance allele in rpoB, KatG, and inhA genes for RIF and INH could serve as a marker for MDR-TB strains. Tracking the most common S531L, S315T, and C15T mutations in rpoB, katG, and inhA genes among RIF- and INH-resistant isolates would be valuable in TB diagnostics and treatment regimens, and could reduce the development and risk of MDR/XDR-TB drug-resistance patterns.

Exploration of the Diversity of Multi-Drug Resistant Mycobacterium Tuberculosis Complex in Lagos, Nigeria Using WGS: Distribution of Lineages, Drug Resistance Patterns and Genetic Mutations

Exploration of the Diversity of Multi-Drug Resistant Mycobacterium Tuberculosis Complex in Lagos, Nigeria Using WGS: Distribution of Lineages, Drug Resistance Patterns and Genetic Mutations

Longitudinal Outbreak of Multidrug-Resistant Tuberculosis in a Hospital Setting, Serbia.

A retrospective population-based molecular epidemiologic study of multidrug-resistant Mycobacterium tuberculosis complex strains in Serbia (2008–2014) revealed an outbreak of TUR genotype strains in a psychiatric hospital starting around 1990. Drug unavailability, poor infection control, and schizophrenia likely fueled acquisition of additional resistance and bacterial fitness–related mutations over 2 decades.

Molecular characteristics of pyrazinamide resistance in Mycobacterium tuberculosis strains

Objective To investigate the correlation between the mutation of pncA gene and the susceptibility to pyrazinamide (PZA) in Mycobacterium tuberculosis complex (MTBC) strains and to analyze the mutation of panD and rpsA genes in wild type isolates without pncA gene mutation. Methods The susceptibilities of 108 MTBC strains to first-line drugs including PZA were detected by using the MGIT 960 TB system. PCR was performed to amplify the 16S rDNA and pncA, panD and rpsA genes. The PCR products were analyzed by DNA sequencing analysis. Results Among the 78 multidrug-resistant MTBC strains, 47 isolates (60%) were resistant to PZA. Four out of 30 (13%) strains that were sensitive to ethambutol, isoniazid, rifampicin and streptomycin (EIRS) were resistant to PZA. The drug-resistant MTBC strains showed higher resistance rate to PZA than that of the EIRS sensitive strains. There were 49 (96%) PZA-resistant isolates and 4 (7%) PZA-sensitive isolates occurred pncA gene mutation. Most of the pncA gene mutations in the genomes of PZA-resistant strains were base substitution mutation, especially the His57Asp substitution. The pncA gene mutations centralized in the regions of 160-169, 203-289, 309-396 and 413-467. Seven novel mutation sites of pncA gene were observed including T175C, C188A, G insertion at 68, AGC insertion at 235, C insertion at 339, CC insertion at 392 and GT deletion at 395. The mutation sites founded in the genomes of PZA-sensitive strains were different from those of the PZA-resistant strains. No mutation of the pncA gene and the upstream regulatory sequence was found in two PZA-resistant strains, NJ44 and NJ108. The sequence analysis of panD and rpsA gene showed that the NJ108 strain had panD gene mutation at G419A, but no mutation was detected in the NJ44 strain. Conclusion The multidrug-resistant MTBC strains showed higher resistance rate to PZA. The pncA gene mutation was common in PZA-resistant MTB strains and the panD gene mutation was also worthy of attention. Key words: Mycobacterium tuberculosis; Pyrazinamide; Drug resistance; Molecular characteristic

Multi-drug resistant Mycobacterium tuberculosis complex genetic diversity and clues on recent transmission in Punjab, Pakistan

Multi-Drug Resistant Tuberculosis (MDR-TB), i.e. bacilli resistant to rifampicin (RIF) and isoniazid (INH), is a major Public Health concern in Pakistan according to WHO estimates (3.5% and 32% of new and retreated cases, respectively). Previous Pakistanis reports identified a correlation between being MDR and belonging to Beijing or EAI lineages in one study, and belonging to “H4”-Ural Euro-American sublineage in another study. In addition, MDR-TB transmission was suspected in Karachi.We tested MDR characteristics on a Punjab sample of 278 clinical isolates (without selection for Multi-Drug Resistance) including new and retreated cases collected from 2008 to 2012. All samples were characterized by a new, microbead-based method named “TB-SPRINT” (molecular diagnostic including spoligotype identification, and genetic resistance determinants to first-line anti-TB drugs RIF and INH). Isolates from 2011 to 2012 (n=100) were further analyzed using 24-loci MIRU-VNTR.We detected 8.7% MDR isolates (CI95%=[5.0; 12.5]), mainly among CAS lineage that predominates in this central-East region of Pakistan. Out of 20 MDR-TB cases, 12 different TB-SPRINT profiles were identified, limiting the suspicion of MDR-TB transmission. 24 MIRU-VNTR confirmed the unrelatedness of isolates with different TB-SPRINT profiles and discriminated 3 isolates with identical TB-SPRINT profiles.In conclusion, our study did not confirm any of the correlations between Multi-Drug Resistance and lineage or sublineage in Punjab, Pakistan. MDR-TB isolates were diverse indicating that transmission is not pervasive. TB-SPRINT proved useful as a first step for detecting MDR-TB likely transmission events, before more extensive genotyping such as 15 or 24 MIRU-VNTR and thorough epidemiological investigation.

Epidemiology of pyrazinamide-resistant tuberculosis in the United States, 1999-2009.

Pyrazinamide (PZA) is essential in tuberculosis treatment. We describe the prevalence, trends, and predictors of PZA resistance in Mycobacterium tuberculosis complex (MTBC) in the United States. We analyzed culture-positive MTBC cases with reported drug susceptibility tests for PZA in 38 jurisdictions routinely testing for PZA susceptibility from 1999 to 2009. National Tuberculosis Genotyping Service data for 2004-2009 were used to distinguish M. tuberculosis from Mycobacterium bovis and determine phylogenetic lineage. Overall 2.7% (2167/79 321) of MTBC cases had PZA resistance, increasing annually from 2.0% to 3.3% during 1999-2009 (P < .001), largely because of an increase in PZA monoresistance. PZA-monoresistant MTBC (vs drug-susceptible) was associated with an age of 0-24 years (adjusted prevalence ratio [aPR],1.50; 95% confidence interval [CI], 1.31-1.71), Hispanic ethnicity (aPR, 3.52; 95% CI, 2.96-4.18), human immunodeficiency virus infection (aPR, 1.43; 95% CI, 1.15-1.77), extrapulmonary disease (aPR, 3.02; 95% CI, 2.60-3.52), and normal chest radiograph (aPR, 1.88; 95% CI, 1.63-2.16) and was inversely associated with Asian (aPR, 0.59; 95% CI, .47-.73) and black (aPR, 0.37; 95% CI, .29-.49) race. Among multidrug-resistant (MDR) cases, 38.0% were PZA-resistant; PZA resistance in MDR MTBC was associated with female sex (aPR, 1.25; 95% CI, 1.08-1.46) and previous tuberculosis diagnosis (aPR, 1.37; 95% CI, 1.16-1.62). Of 28 080 cases with genotyping data, 925 (3.3%) had PZA resistance; 465 of 925 (50.3%) were M. bovis. In non-MDR M. tuberculosis cases, PZA resistance was higher in the Indo-Oceanic than the East Asian lineage (2.2% vs 0.9%, respectively; aPR, 2.26; 95% CI, 1.53-3.36), but in MDR cases it was lower in the Indo-Oceanic lineage (22.0% vs 43.4%, respectively; aPR, 0.54; 95% CI, .32-.90). Specific human and mycobacterial characteristics were associated with PZA-resistant MTBC, reflecting both specific subgroups of the population and phylogenetic lineages of the mycobacteria.

Cross-resistance between rifampin and rifabutin in multidrug resistant Mycobacterium tuberculosis complex strains

To study the cross-resistance between rifampin and rifabutin in multidrug resistant Mycobacterium tuberculosis complex strains, and therefore to provide laboratory data for using rifabutin in the treatment of multidrug resistant tuberculosis. The MIC(90) of rifabutin and rifampin against 99 multidrug resistant Mycobacterium tuberculosis clinical strains were determined by microplate assays. Statistical analysis was performed by using the χ(2) test and the t test. The cross-resistance rate between rifampicin and rifabutin was 85.9% (85/99), but the MIC(90) of rifabutin (≤ 16 mg/L, median 2 mg/L) was significantly lower than that of rifampicin (≥ 2 mg/L, median > 32 mg/L). The cross-resistance rate increased with the resistance level of rifampicin. The cross-resistance strains in the lower and the medium groups were 0/9 and 5/9 respectively, while the strains of the high rifampicin-resistant group were almost all cross-resistant (98.8%, 80/81). Rifabutin had activities against rifampin resistant Mycobacterium tuberculosis complex strains in vitro, and therefore may be used as an alternative for the treatment of multidrug resistant tuberculosis.

Long-term molecular surveillance of multidrug-resistant tuberculosis in Spain

The data presented here span 11years (1998–2008) of monitoring of multidrug-resistant tuberculosis (MDR-TB) clustering through molecular typing techniques in Spain. The molecular and epidemiological data of 480 multidrug-resistant Mycobacterium tuberculosis complex isolates were analyzed.Thirty-one clusters involving 157 (32.7%) patients were identified. The proportion of immigrants increased substantially over the study period reaching 65% in 2008; however, the clustering rate remained stable indicating that local transmission was little influenced by imported MDR-TB. The three major clusters respond to the persistence of two autochthonous strains throughout the study period and an extensively drug-resistant (XDR) Mycobacterium bovis outbreak with only two cases was reported since 2002.Molecular and epidemiological evidence for the importation of new strains and their spread within the community was found. Immigrant-only clusters most often grouped patients infected abroad with strains belonging to rare spoligotypes. Conversely, widespread spoligotypes of the Latin-American and Mediterranean (LAM) and Haarlem families were responsible for the majority of the MDR-TB local transmission.The demonstration of clusters spanning several Spanish regions that have been ongoing throughout the study period makes it advisable to maintain a continuous molecular surveillance in order to monitor the spread of MDR-TB.

New N‐Alkyl‐1,2‐dihydro‐2‐thioxo‐3‐pyridinecarbothioamides as Antituberculous Agents with Improved Pharmacokinetics.

AbstractFor Abstract see ChemInform Abstract in Full Text.

New N-Alkyl-1,2-dihydro-2-thioxo-3-pyridinecarbothioamides as antituberculous agents with improved pharmacokinetics

Infections caused by multidrug-resistant Mycobacterium tuberculosis (MT) and non-tuberculous mycobacteria are difficult to treat and, indeed, new therapeutic agents are being sought. As a part of an ongoing research in our laboratories, novel N-alkyl-1,2-dihydro-2-thioxo-3-pyridinecarbothioamides have been synthesized and evaluated against several strains of MT and Mycobacterium avium complex (MAC). The pharmacokinetics and relative bioavailability after intravenous administration of three derivatives have been investigated. Introduction of a hydroxyl or a tertiary amino group in the N-alkyl chain resulted in an improved pharmacokinetic profile without affecting sensitively the antituberculous potency.