Multidrug-resistant tuberculosis

Abstract

Despite the efforts made worldwide to reduce the number of cases of drug-susceptible tuberculosis, multidrug-resistant tuberculosis (MDR-TB) constitutes an important public health issue. Around 440,000 new cases of MDR-TB are estimated annually, although in 2008 only 7% of these (29,423 cases) were notified. The laboratory tests for diagnosing resistance may be phenotypic (based on culture growth in the presence of drugs) or genotypic (i.e. identification of the presence of mutations that confer resistance). The urgent need for a rapid means of detecting resistance to anti-TB drugs has resulted in the development of many genotypic methods over recent years. The treatment of MDR-TB is expensive, complex, prolonged (18-24 months) and associated with a higher incidence of adverse reactions. Some basic principles must be observed when prescribing an adequate treatment regimen for MDR-TB: (a) the association of at least four drugs (three of which should not have been used previously); (b) use of a fluoroquinolone; and (c) use of an injectable anti-TB drug. In Brazil, the therapeutic regimen for MDR-TB has been standardized and consists of five drugs: terizidone, levofloxacin, pyrazinamide, ethambutol and an aminoglycoside (streptomycin or amikacin). Pulmonary resection is an important tool in the coadjuvant treatment of MDR-TB. While a recent meta-analysis revealed an average cure rate of MDR-TB of 69%, clinical studies are currently being conducted with new drugs and with drugs already available on the market but with a new indication for TB, with encouraging results that will enable more effective treatment regimens to be planned in the future.

Spoligotyping and drug sensitivity of Mycobacterium tuberculosis isolated from pulmonary tuberculosis patients in the Arsi Zone of southeastern Ethiopia

“…In the present study, the GenoType MTBDRplus assay demonstrated a mutation for 5.4% (5/92) isoniazid-resistant isolates and only 1.1% rifampicin-resistant isolates. Many research findings indicate that many of the isoniazid-resistant strains contain mutations in codon 315 of katG [37]. In agreement with the previous reports, our finding showed that all mutations for isoniazid resistance were found in the katG S315T1 (5.4%) whereas no mutations were found in the promoter region of the inhA gene.…”

Spoligotyping and Drug Sensitivity of Mycobacterium tuberculosis isolated from Pulmonary Tuberculosis Patients in the Arsi Zone of South Eastern Ethiopia

“…In the present study, the GenoType MTBDRplus assay demonstrated a mutation from 5.4% (5/92) Isoniazid resistant isolates and only 1.1% Rifampicin resistant isolate. Many research findings indicate that much of the INH-resistant strains contain mutations in codon 315 of katG (Lemos and Matos, 2013). In agreement with the previous reports, our finding showed that all mutation for INH resistance was found in the katGS315T1 (5.4%) whereas the mutations in the promoter region of the inhA gene was not observed.…”

Drug resistance pattern, related socio- demographic factors and preventive practices among MDR-TB patients: An experience from a tertiary care setting

“…65.9% ( 27) were tested drug resistance by LPA method, 24.4 % (10) by CBNAAT method and rest by MGIT-960 method. About 53.7% (22) patients were found to be resistant to Rifampicin only, 46.3% (19) to both Rifampicin and Isoniazid. All the patients were nonreactive to ICTC testing.…”