Antimicrobial susceptibility determined by the E test, Löwenstein-Jensen proportion, and DNA sequencing methods among Mycobacterium tuberculosis isolates discrepancies, preliminary results

Freixo, Maria Ines Moura; Caldas, Paulo; Said, Abbadi; Martins, Fátima; Brito, Rossana Coimbra; Fonseca, Leila de Souza; Saad, Maria Helena Féres

doi:10.1590/s0074-02762004000100019

Cited by 5 publications

(2 citation statements)

References 15 publications

(3 reference statements)

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“…Another result is that the correlation between the DST result and mutation in the genes associated with resistance to INH and RIF failed. Discrepancies in molecular detection related to phenotypic results have been previously documented, including those in Brazilian clinical strains (14,15). Mutation in these strains may have occurred in a different region than that of the target gene or perhaps there were other resistance mechanisms involved.…”

Section: Patient Follow-up Results and Discussionmentioning

confidence: 99%

Phenotypic and genotypic variant of MDR-Mycobacterium tuberculosis multiple isolates in the same tuberculosis episode, Rio de Janeiro, Brazil

Andrade

Machado

Leite

et al. 2009

Braz J Med Biol Res

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Assuming that the IS6110-restriction fragment length polymorphism (RFLP) changes at a constant rate of 3.2 years, this methodology was applied to demonstrate, for the first time, variant patterns of Mycobacterium tuberculosis (MTB) in multiple isolates obtained at short time intervals from sputum and blood of an HIV + patient with multiple admissions to the Emergency Room and to the multidrug-resistant tuberculosis (MDR-TB) Reference Center of a secondary-care hospital in Rio de Janeiro, Brazil. In sputum, the IS6110-RFLP appeared in isolates with two variant patterns with 10 and 13 IS6110 copies. However, blood presented only the pattern corresponding to 10 copies, suggesting compartmentalization. With regard to the exact match of 10 of 13 bands, this may be a subpopulation with the same clonal origin and this may be related to the IS6110 transposition. A susceptibility test demonstrated an MDR profile (INH R , RIF R , SM R , and EMB R ), with the sputum isolate also exhibiting EMB S (R = resistant; S = sensitive). A gene mutation confirmed resistance only to streptomycin. There was agreement between the results of the phenotypic test and the clinical response to MDR-TB treatment, suggesting serious implications with regard to treatment administration based exclusively on molecular methods, and calling attention to the fact that more effective control strategies against the emergence of MDR strains must be implemented by the TB control program to prevent transmission of MDR-MTB strains at health facilities in areas highly endemic for TB.

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Section: Patient Follow-up Results and Discussionmentioning

confidence: 99%

Phenotypic and genotypic variant of MDR-Mycobacterium tuberculosis multiple isolates in the same tuberculosis episode, Rio de Janeiro, Brazil

Andrade

Machado

Leite

et al. 2009

Braz J Med Biol Res

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“…Owing to their well-known use for other bacteria and the possibility of obtaining rapid results without additional equipment, Etest strips have also been tried for DST of M. tuberculosis [58,59]. Good overall agreement with conventional DST for RMP and INH has also been reported for this method.…”

Section: Etestmentioning

confidence: 99%

Drug-susceptibility testing in TB: current status and future prospects

Richter¹,

Rüsch-Gerdes²,

Hillemann³

2009

Expert Review of Respiratory Medicine

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The rising number of resistant and multidrug-resistant Mycobacterium tuberculosis strains and the emergence of extensively drug-resistant strains substantiate the urgent demand for rapid and reliable techniques for the detection of drug-resistant TB. In recent years, a multitude of techniques for rapid drug-susceptibility testing have been designed and evaluated. Two different strategies for the assessment of drug resistance can be followed; phenotypic determination has been common practice for years, whereas more recently the genetic detection of mutations that confer for drug resistance has been established. Novel liquid culture-based drug-susceptibility testing techniques have been evaluated; several of them have proved their reliability and accuracy, while others need more evaluation or a different performance due to biosafety risks. Among the molecular tests, line-probe assays seem to be the most promising tools for a rapid and very specific and sensitive detection of multidrug-resistant M. tuberculosis.

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Identifying isoniazid resistance markers to guide inclusion of high-dose isoniazid in tuberculosis treatment regimens

Rivière

Whitfield

Nelen

et al. 2020

Clinical Microbiology and Infection

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Objectives: Effective use of antibiotics is critical to control the global tuberculosis pandemic. High-dose isoniazid (INH) can be effective in the presence of low-level resistance. We performed a systematic literature review to improve our understanding of the differential impact of genomic Mycobacterium tuberculosis (Mtb) variants on the level of INH resistance. The following online databases were searched: PubMed, Web of Science and Embase. Articles reporting on clinical Mtb isolates with linked genotypic and phenotypic data and reporting INH resistance levels were eligible for inclusion. Methods: All genomic regions reported in the eligible studies were included in the analysis, including: katG, inhA, ahpC, oxyR-ahpC, furA, fabG1, kasA, rv1592c, iniA, iniB, iniC, rv0340, rv2242 and nat. The level of INH resistance was determined by MIC: low-level resistance was defined as 0.1e0.4 mg/mL on liquid and 0.2e1.0 mg/mL on solid media, high-level resistance as >0.4mg/mL on liquid and >1.0 mg/mL on solid media. Results: A total of 1212 records were retrieved of which 46 were included. These 46 studies reported 1697 isolates of which 21% (n ¼ 362) were INH susceptible, 17% (n ¼ 287) had low-level, and 62% (n ¼ 1048) high-level INH resistance. Overall, 24% (n ¼ 402) of isolates were reported as wild type and 76% (n ¼ 1295) had 1 relevant genetic variant. Among 1295 isolates with 1 variant, 78% (n ¼ 1011) had a mutation in the katG gene. Of the 867 isolates with a katG mutation in codon 315, 93% (n ¼ 810) had high-level INH resistance. In contrast, only 50% (n ¼ 72) of the 144 isolates with a katG variant not in the 315-position had high-level resistance. Of the 284 isolates with 1 relevant genetic variant and wild type katG gene, 40% (n ¼ 114) had high-level INH resistance. Conclusions: Presence of a variant in the katG gene is a good marker of high-level INH resistance only if located in codon 315.

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Antimicrobial susceptibility determined by the E test, Löwenstein-Jensen proportion, and DNA sequencing methods among Mycobacterium tuberculosis isolates discrepancies, preliminary results

Abstract: Mycobacterium tuberculosis strains resistant to streptomycin (SM), isoniazid (INH), and/or rifampin (RIF) as

Cited by 5 publications

References 15 publications

Phenotypic and genotypic variant of MDR-Mycobacterium tuberculosis multiple isolates in the same tuberculosis episode, Rio de Janeiro, Brazil

Phenotypic and genotypic variant of MDR-Mycobacterium tuberculosis multiple isolates in the same tuberculosis episode, Rio de Janeiro, Brazil

Drug-susceptibility testing in TB: current status and future prospects

Identifying isoniazid resistance markers to guide inclusion of high-dose isoniazid in tuberculosis treatment regimens

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