Correlating rrs and eis promoter mutations in clinical isolates of Mycobacterium tuberculosis with phenotypic susceptibility levels to the second-line injectables

Kambli, Priti; Ajbani, Kanchan; Nikam, Chaitali; Sadani, Meeta; Shetty, Anjali; Udwadia, Zarir; Georghiou, Sophia B.; Rodwell, Timothy C.; Catanzaro, Antonino; Rodrigues, Camilla

doi:10.1016/j.ijmyco.2015.09.001

Cited by 51 publications

(51 citation statements)

References 17 publications

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“…The other four specimens were KAN s in both DST runs, indicating that these mutants had MICs below the tested KAN critical concentration. While eis promoter mutations have been well documented to confer only low-level KAN resistance (21,44), recent studies have found M. tuberculosis eis mutants to have broad KAN MIC ranges (0.625 to 32 g/ml) via liquid-based DST methods (45,46). As such, the eis promoter mutants identified in our study may have had MICs around the critical concentration.…”

Section: Rifmentioning

confidence: 60%

Frequency and Distribution of Tuberculosis Resistance-Associated Mutations between Mumbai, Moldova, and Eastern Cape

Georghiou

Seifert

Catanzaro

et al. 2016

Antimicrob Agents Chemother

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f Molecular diagnostic assays, with their ability to rapidly detect resistance-associated mutations in bacterial genes, are promising technologies to control the spread of drug-resistant tuberculosis (DR-TB). Sequencing assays provide detailed information for specific gene regions and can help diagnostic assay developers prioritize mutations for inclusion in their assays. We performed pyrosequencing of seven Mycobacterium tuberculosis gene regions (katG, inhA, ahpC, rpoB, gyrA, rrs, and eis) for 1,128 clinical specimens from India, Moldova, and South Africa. We determined the frequencies of each mutation among drug-resistant and -susceptible specimens based on phenotypic drug susceptibility testing results and examined mutation distributions by country. The most common mutation among isoniazid-resistant (INH r ) specimens was the katG 315ACC mutation (87%). However, in the Eastern Cape, INH r specimens had a lower frequency of katG mutations (44%) and higher frequencies of inhA (47%) and ahpC (10%) promoter mutations. The most common mutation among rifampin-resistant (RIF r ) specimens was the rpoB 531TTG mutation (80%). The mutation was common in RIF r specimens in Mumbai (83%) and Moldova (84%) but not the Eastern Cape (17%), where the 516GTC mutation appeared more frequently (57%). The most common mutation among fluoroquinolone-resistant specimens was the gyrA 94GGC mutation (44%). The rrs 1401G mutation was found in 84%, 84%, and 50% of amikacin-resistant, capreomycin-resistant, and kanamycin (KAN)-resistant (KAN r ) specimens, respectively. The eis promoter mutation ؊12T was found in 26% of KAN r and 4% of KAN-susceptible (KAN s ) specimens. Inclusion of the ahpC and eis promoter gene regions was critical for optimal test sensitivity for the detection of INH resistance in the Eastern Cape and KAN resistance in Moldova. (This study has been registered at ClinicalTrials.gov under registration number NCT02170441.) I n 2014, an estimated 9.6 million people developed tuberculosis (TB), and 1.5 million people died of their infection (1). Although global TB incidence rates have fallen an average of 1.5% per year since 2000, the rise of drug-resistant TB (DR-TB) globally has complicated TB control efforts (1). The World Health Organization (WHO) estimates that as many as 1 in every 20 new, active TB infections is now drug resistant (1). One of the major roadblocks in combating this growing problem has been the lack of diagnostic technology for DR-TB. Current growth-based culture and drug susceptibility testing (DST) methods can take several weeks to months to yield results (2). While waiting on culture results, physicians are forced to treat their patients empirically, adjusting treatment regimens only once DST results become available. As a result, many undiagnosed DR-TB patients are being given medications that are ineffective, which amplifies resistance, increases the risk of mortality, and increases the risk of transmitting DR-TB infections in the community.Rapid molecular diagnostic assays for DR-TB have the p...

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Section: Rifmentioning

confidence: 60%

Frequency and Distribution of Tuberculosis Resistance-Associated Mutations between Mumbai, Moldova, and Eastern Cape

Georghiou

Seifert

Catanzaro

et al. 2016

Antimicrob Agents Chemother

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“…Some of these drawbacks could be overcome by designing the assay to specifically address the detection of synonymous mutations as recently done for the Xpert Ultra; however, this strategy requires a priori knowledge of all the possible silent mutations in the targeted region. Fourth, clear understanding of the relationship between genotype and phenotype and clinical outcome is not always available, and several factors contribute in complicating the clinical interpretation of genetic polymorphisms …”

Section: Discussionmentioning

confidence: 99%

“…Meanwhile, uncommon mutations at codon 1484 were also reported to confer resistance in KAN and AMK . Mutations at positons −10 and −35 of the promoter region of eis have been also been shown to confer resistance to KAN …”

Section: Mechanisms Of Drug Resistance In Mtbmentioning

confidence: 99%

Drug resistance mechanisms and drug susceptibility testing for tuberculosis

et al. 2018

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Tuberculosis (TB) caused by Mycobacterium tuberculosis (MTB) is the deadliest infectious disease and the associated global threat has worsened with the emergence of drug resistance, in particular multidrug-resistant TB (MDR-TB) and extensively drug-resistant TB (XDR-TB). Although the World Health Organization (WHO) End-TB Strategy advocates for universal access to antimicrobial susceptibility testing, this is not widely available and/or it is still underused. The majority of drug resistance in clinical MTB strains is attributed to chromosomal mutations. Resistance-related mutations could also exert certain fitness cost to the drug-resistant MTB strains and growth fitness could be restored by the presence of compensatory mutations. Understanding these underlying mechanisms could provide an important insight into TB pathogenesis and predict the future trend of MDR-TB global pandemic. This review covers the mechanisms of resistance in MTB and provides a comprehensive overview of current phenotypic and molecular approaches for drug susceptibility testing, with particular attention to the methods endorsed and recommended by the WHO.

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“…As indicated by Georghiou et al (20), rrs MUT1 A1401G mutation is a moderate predictor of CAP resistance. Therefore, CAP resistance should be confirmed phenotypically prior to exclusion of the drug from a treatment regimen (21). There were 31 isolates identified as phenotypically XDR, and the GenoType MTBDRsl VER 2.0 assay achieved 97.0% agreement between the index and gold standard tests.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of the GenoType MTBDR sl Version 2.0 Assay for Second-Line Drug Resistance Detection of Mycobacterium tuberculosis Isolates in South Africa

et al. 2017

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Early detection of resistance to second-line antituberculosis drugs is important for the management of multidrug-resistant tuberculosis (MDR-TB). The GenoType MTBDRsl version 2.0 (VER 2.0) line probe assay has been redesigned for molecular detection of resistance-conferring mutations of fluoroquinolones (FLQ) (gyrA and gyrB genes) and second-line injectable drugs (SLID) (rrs and eis genes). The study evaluated the diagnostic performance of the GenoType MTBDRsl VER 2.0 assay for the detection of second-line drug resistance compared with phenotypic drug susceptibility testing (DST), using the Bactec MGIT 960 system on Mycobacterium tuberculosis complex isolates from South Africa. A total of 268 repository isolates collected between 2012 and 2014, which were rifampin monoresistant or MDR based on DST, were selected. MTBDRsl VER 2.0 testing was performed on these isolates and the results analyzed. The MTBDRsl VER 2.0 sensitivity and specificity indices for culture isolates were the following: FLQ, 100% (95% confidence interval [CI] 95.8 to 100%) and 98.9% (95% CI, 96.1 to 99.9%); SLID, 89.2% (95% CI, 79.1 to 95.6%) and 98.5% (95% CI, 95.7 to 99.7%). The sensitivity and specificity observed for individual SLID were the following: amikacin, 93.8% (95% CI, 79.2 to 99.2%) and 98.5% (95% CI, 95.5 to 99.7%); kanamycin, 89.2% (95% CI, 79.1 to 95.6%) and 98.5% (95% CI, 95.5 to 99.7%); and capreomycin, 86.2% (95% CI, 68.3 to 96.1%) and 95.9% (95% CI, 92.2 to 98.2%). An interoperator reproducibility of 100% and an overall interlaboratory performance of 93% to 96% were found. The overall improvement in sensitivity and specificity with excellent reproducibility makes the GenoType MTBDRsl VER 2.0 a highly suitable tool for rapid screening of clinical isolates for second-line drug resistance for use in high-burden TB/HIV settings.

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Correlating rrs and eis promoter mutations in clinical isolates of Mycobacterium tuberculosis with phenotypic susceptibility levels to the second-line injectables

Cited by 51 publications

References 17 publications

Frequency and Distribution of Tuberculosis Resistance-Associated Mutations between Mumbai, Moldova, and Eastern Cape

Frequency and Distribution of Tuberculosis Resistance-Associated Mutations between Mumbai, Moldova, and Eastern Cape

Drug resistance mechanisms and drug susceptibility testing for tuberculosis

Evaluation of the GenoType MTBDR sl Version 2.0 Assay for Second-Line Drug Resistance Detection of Mycobacterium tuberculosis Isolates in South Africa

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