International Journal of Infectious Diseases (Oct 2015)

Multidrug-resistant and heteroresistant Mycobacterium tuberculosis and associated gene mutations in Ethiopia

  • Daniel Mekonnen,
  • Aschalew Admassu,
  • Wondemagegn Mulu,
  • Aranzazu Amor,
  • Agustín Benito,
  • Woynshet Gelaye,
  • Fantahun Biadglegne,
  • Bayeh Abera

DOI
https://doi.org/10.1016/j.ijid.2015.06.013
Journal volume & issue
Vol. 39, no. C
pp. 34 – 38

Abstract

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Background: The prevalence of multidrug-resistant tuberculosis (TB) among new and retreatment cases in 2011 in Ethiopia was 2.7% and 17.9%, respectively. However, data on heteroresistance and gene mutation profiles of Mycobacterium tuberculosis were not documented. Methods: A cross-sectional study was conducted on 413 TB-positive clinical specimens submitted between 2012 and 2014 to Bahir Dar Regional Laboratory Center for confirmation of multidrug resistance. Resistance determining genes were analyzed using a line probe assay. Results: Of 413 M. tuberculosis isolates, 150 (36.3%) were multidrug-resistant, 19 (4.6%) were resistant only to rifampicin, and 26 (6.3%) were resistant to isoniazid. Of 169 rifampicin-resistant and 176 isoniazid-resistant isolates, only eight (4.7%) showed rifampicin heteroresistance and only two (1.13%) showed isoniazid heteroresistance. Failing of the rpoB WT8 gene with corresponding hybridization of rpoB MUT3 (S531L substitution) accounted for 85 (50.3%) rifampicin-resistant mutations. Among 176 isoniazid-resistant isolates, 155 (88.1%) strains had the Ser315Thr1 substitution. Conclusions: The prevalence of multidrug-resistant M. tuberculosis was high in the study area. Ser531Leu and Ser315Thr1 substitutions were the highest gene mutations for rifampicin and isoniazid, respectively.

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