International Journal of Mycobacteriology (Jan 2019)

Competitive fitness of Mycobacterium tuberculosis in vitro

  • Ousmane Kodio,
  • Antieme Combo Georges Togo,
  • Yeya dit Sadio Sarro,
  • Bintou Fane,
  • Fatimata Diallo,
  • Amadou Somboro,
  • Boureima Degoga,
  • Mahamadou Kone,
  • Gagni Coulibaly,
  • Mohamed Tolofoudje,
  • Sidy Bane,
  • Moumine Sanogo,
  • Bourahima Kone,
  • Nadie Coulibaly,
  • Djeneba Dabitao,
  • Bocar Baya,
  • Mamoudou Maiga,
  • Flabou Bougoudogo,
  • Fasse Samake,
  • Sounkalo Dao,
  • Seydou Doumbia,
  • Souleymane Diallo,
  • Bassirou Diarra

DOI
https://doi.org/10.4103/ijmy.ijmy_97_19
Journal volume & issue
Vol. 8, no. 3
pp. 287 – 291

Abstract

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Background: While, bacteria resistance mutations can affect competitive fitness, given our multidrug-resistant (MDR) prevalence, we conducted this study to determine the impact of MDR on the competitive fitness of Mycobacterium tuberculosis (MTB) complex MDR strains. We conducted a cross-sectional study at the University Clinical Research Center (UCRC) from January to December 2017. New TB patients over aged of 18 were recruited at University teaching hospital and health reference centers of Bamako in USTTB Ethical committee approved protocols. Methods: MDR and drug-susceptible (wild-type [WT]) MTB strains (T1 and Beijing) and MTB H37Rv were competed on solid media in UCRC's Tuberculosis Laboratory. Competitive and individual cultures were incubated for 14 days at 37°C with 7% CO2. Number of generation, generation time, and relative competitive fitness (W) of the strains were calculated. Data were analyzed with Epi-Info 7.1.5.2 software (CDC). P value was considered significant when it was <0.05. Scientific calculator (CS-82TL) was used for competitive fitness parameters calculations. Results: We performed 24 competitive cultures and 10 individual cultures. In individual cultures, strains' generation number was for Beijing (WT: 4.60 and mutant MR: 4.40), T1 (WT: 2.69 and MR: 2.37), and H37Rv: 2.91. Generation number of WT strains was less than those of MDR strains in both individual and competitive culture. Relative competitive fitness was below 1 (W<1) in 83.3%. Conclusion: MDR strains were less competitive than WT strains in 83.3% of cases. Resistant mutation impacts bacteria fitness.

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