scholarly journals Validation of Cycloserine Efficacy in Treatment of Multidrug-Resistant and Extensively Drug-Resistant Tuberculosis in Beijing, China

2018 ◽  
Vol 62 (3) ◽  
Author(s):  
Xia Yu ◽  
Xiling Zeng ◽  
Wenhui Shi ◽  
Yanjie Hu ◽  
Wenjuan Nie ◽  
...  

ABSTRACTCycloserine (Cs) is recommended by the World Health Organization as a second-line drug to treat multidrug-resistant tuberculosis (MDR-TB); however, its efficacy has never been sufficiently evaluated. To gain some insights into the value of cycloserine for MDR-TB treatment,in vitrobacteriostatic effect was determined and patient validations were performed prospectively. Thein vitroactivity of Cs against 104 wild-typeMycobacterium tuberculosisstrains was determined, and serum Cs concentrations were measured for 73 MDR TB patients 2 h after administration. The treatment outcomes for 27 MDR-TB patients who had baseline isolates and were treated with Cs-containing regimens were followed up. The MICs for 90% of the recruited 104 wild-type strains were below 32 μg/ml. Eighteen out of 52 patients had peak serum concentrations (Cmax) below 20 μg/ml at the dosage of 500 mg daily, while 13 out of 21 patients had peak serum concentrations higher than 35 μg/ml at the dosage of 750 mg daily. The percentage of favorable treatment outcomes among patients with aCmax/MIC ratio of ≥1 was statistically significantly higher than that among the group with aCmax/MIC ratio of <1 (P= 0.022). The epidemiological cutoff value for Cs susceptibility testing was 32 μg/ml. A high percentage of patients receiving the recommended dosage of 10 mg/kg for Cs administration could not acquire desirable blood concentrations; therefore, adjusting the dosage according to drug concentration monitoring is necessary. TheCmax/MIC ratio might be a good indicator for predicting the treatment outcome for patients with MDR-TB or extensively drug-resistant TB (XDR-TB) who are being administered Cs-containing regimens.

2018 ◽  
Vol 62 (8) ◽  
Author(s):  
Zhaojing Zong ◽  
Wei Jing ◽  
Jin Shi ◽  
Shu'an Wen ◽  
Tingting Zhang ◽  
...  

ABSTRACT Oxazolidinones are efficacious in treating mycobacterial infections, including tuberculosis (TB) caused by drug-resistant Mycobacterium tuberculosis. In this study, we compared the in vitro activities and MIC distributions of delpazolid, a novel oxazolidinone, and linezolid against multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB) in China. Additionally, genetic mutations in 23S rRNA, rplC, and rplD genes were analyzed to reveal potential mechanisms underlying the observed oxazolidinone resistance. A total of 240 M. tuberculosis isolates were included in this study, including 120 MDR-TB isolates and 120 XDR-TB isolates. Overall, linezolid and delpazolid MIC90 values for M. tuberculosis isolates were 0.25 mg/liter and 0.5 mg/liter, respectively. Based on visual inspection, we tentatively set epidemiological cutoff (ECOFF) values for MIC determinations for linezolid and delpazolid at 1.0 mg/liter and 2.0 mg/liter, respectively. Although no significant difference in resistance rates was observed between linezolid and delpazolid among XDR-TB isolates (P > 0.05), statistical analysis revealed a significantly greater proportion of linezolid-resistant isolates than delpazolid-resistant isolates within the MDR-TB group (P = 0.036). Seven (53.85%) of 13 linezolid-resistant isolates were found to harbor mutations within the three target genes. Additionally, 1 isolate exhibited an amino acid substitution (Arg126His) within the protein encoded by rplD that contributed to high-level resistance to linezolid (MIC of >16 mg/liter), compared to a delpazolid MIC of 0.25. In conclusion, in vitro susceptibility testing revealed that delpazolid antibacterial activity was comparable to that of linezolid. A novel mutation within rplD that endowed M. tuberculosis with linezolid, but not delpazolid, resistance was identified.


2016 ◽  
Vol 4 (5) ◽  
Author(s):  
Htin Lin Aung ◽  
Thanda Tun ◽  
Elizabeth Permina ◽  
Wint Wint Nyunt ◽  
Si Thu Aung ◽  
...  

Multidrug-resistant tuberculosis (MDR-TB) and lately, extensively drug-resistant TB (XDR-TB) are increasing global health concerns. Here, we present the genome sequences of two MDR-TB isolates from Myanmar, one of 27 countries with a high MDR-TB burden, and describe a number of mutations consistent with these being XDR-TB isolates.


BMJ Open ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. e031663
Author(s):  
Nomonde Ritta Mvelase ◽  
Yusentha Balakrishna ◽  
Keeren Lutchminarain ◽  
Koleka Mlisana

ObjectivesSouth Africa ranks among the highest drug-resistant tuberculosis (DR-TB) burdened countries in the world. This study assessed the changes in resistance levels in culture confirmed Mycobacterium tuberculosis (MTB) in the highest burdened province of South Africa during a period where major changes in diagnostic algorithm were implemented.SettingThis study was conducted at the central academic laboratory of the KwaZulu-Natal province of South Africa.ParticipantsWe analysed data for all MTB cultures performed in the KwaZulu-Natal province between 2011 and 2014. The data were collected from the laboratory information system.ResultsOut of 88 559 drug susceptibility results analysed, 18 352 (20.7%) were resistant to rifampicin (RIF) and 19 190 (21.7%) showed resistance to isoniazid (INH). The proportion of rifampicin resistant cases that were mono-resistant increased from 15.3% in 2011 to 21.4% in 2014 while INH mono-resistance (IMR) showed a range between 13.8% and 21.1%. The multidrug-resistant tuberculosis (MDR-TB) rates increased from 18.8% to 23.9% and the proportion of MDR-TB cases that had extensively drug-resistant tuberculosis remained between 10.2% and 11.1%. Most drug resistance was found in females between the ages of 15 and 44 years and the northern districts bordering high MDR-TB regions had the highest MDR-TB rates.ConclusionOur findings show increasing RIF mono-resistance (RMR) and a substantial amount of IMR. This highlights a need for an initial test that detects resistance to both these drugs so as to avoid using RIF monotherapy during continuous phase of treatment in patients with IMR. Furthermore, addition of INH will benefit patients with RMR. Although DR-TB is widespread, HIV and migration influence its distribution; therefore, TB control strategies should include interventions that target these aspects.


2021 ◽  
Vol 9 (5) ◽  
pp. 1074
Author(s):  
Francesco Pecora ◽  
Giulia Dal Canto ◽  
Piero Veronese ◽  
Susanna Esposito

Multidrug-resistant (MDR) tuberculosis (TB) has been emerging at an alarming rate over the last few years. It has been estimated that about 3% of all pediatric TB is MDR, meaning about 30,000 cases each year. Although most children with MDR-TB can be successfully treated, up to five years ago effective treatment was associated with a high incidence of severe adverse effects and patients with extensively drug-resistant (XDR) TB had limited treatment options and no standard regimen. The main objective of this manuscript is to discuss our present knowledge of the management of MDR- and XDR-TB in children, focusing on the characteristics and available evidence on the use of two promising new drugs: bedaquiline and delamanid. PubMed was used to search for all of the studies published up to November 2020 using key words such as “bedaquiline” and “delamanid” and “children” and “multidrug-resistant tuberculosis” and “extensively drug-resistant tuberculosis”. The search was limited to articles published in English and providing evidence-based data. Although data on pediatric population are limited and more studies are needed to confirm the efficacy and safety of bedaquiline and delamanid, their use in children with MDR-TB/XDR-TB appears to have good tolerability and efficacy. However, more evidence on these new anti-TB drugs is needed to better guide their use in children in order to design effective shorter regimens and reduce adverse effects, drug interactions, and therapeutic failure.


2021 ◽  
Vol 91 (1) ◽  
Author(s):  
Varvara Solodovnikova ◽  
Ajay M.V. Kumar ◽  
Hennadz Hurevich ◽  
Yuliia Sereda ◽  
Vera Auchynka ◽  
...  

There is limited evidence describing the safety and effectiveness of bedaquiline and delamanid containing regimens in children and adolescents with Multidrug-Resistant Tuberculosis (MDR-TB) and Extensively Drug-Resistant Tuberculosis (XDR-TB) globally. In this nationwide descriptive cohort study from Belarus, we examined adverse drug events, time to culture conversion, treatment outcomes including post-treatment recurrence among children and adolescents (<18 years of age) treated with bedaquiline and/or delamanid containing regimens from 2015 to 2019. Of the 40 participants included (55% females; age range 10-17 years), 20 (50%) had XDR-TB and 15 (38%) had resistance to either fluoroquinolone or second-line injectable. Half of the patients received delamanid and another half received bedaquiline with one patient receiving both drugs. AEs were reported in all the patients. A total of 224 AEs were reported, most of which (76%) were mild in nature. Only 10 (5%) AEs were graded severe and one AE was graded life-threatening. A total of 7 AEs (3%) were classified as ‘serious’ and only one patient required permanent discontinuation of the suspected drug (linezolid). Most of the AEs (94%) were resolved before the end of treatment. All patients culture-positive at baseline (n=34) became culture-negative within three months of treatment. Median time to culture conversion was 1.1 months (interquartile range: 0.9-1.6). Two patients were still receiving treatment at the time of analysis. The remaining 38 patients successfully completed treatment. Among those eligible and assessed at 6 (n=32) and 12 months (n=27) post-treatment, no recurrences were detected. In conclusion, treatment of children and adolescents with MDR-TB and XDR-TB using bedaquiline and/or delamanid containing regimens was effective and had favourable safety profile. Achieving such excellent outcomes under programmatic settings is encouraging for other national tuberculosis programmes, which are in the process of introducing or scaling-up the use of these new drugs in their countries.


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