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01.12.2015 | Research article | Ausgabe 1/2015 Open Access

BMC Public Health 1/2015

Molecular typing and drug sensitivity testing of Mycobacterium tuberculosis isolated by a community-based survey in Ethiopia

Zeitschrift:
BMC Public Health > Ausgabe 1/2015
Autoren:
Muluwork Getahun, Gobena Ameni, Abebaw Kebede, Zelalem Yaregal, Elena Hailu, Grimay Medihn, Daniel Demssie, Feven Girmachew, Yetnebersh Fiseha, Abyot Meaza, Nathneal Dirse, Mulualem Agonafir, Feleke Dana, Fasil Tsegaye, Zeleke Alebachew, Almaz Abebe, Amha Kebede, Eshetu Lemma
Wichtige Hinweise

Competing interests

We declare that there are no financial, professional or personal competing interests that might have influenced the performance or presentation of the work described in this manuscript.

Authors’ contribution

MG conceived, designed, carried out the study, and wrote the manuscript. GA advised in proposal development, laboratory analysis, data analysis, and manuscript write up. AK involved in data analysis and manuscripts write up. ZY carried out quality control for all laboratory analysis. EH carried out spoligotyping, GM advised in proposal development, data analysis and manuscript write up. DD, FG, YF, AM and ND carried out drug susceptibility testing. ZA, FT, MA and FD carried out data extraction and data analysis. EL, AK, and AA advise in proposal development, data analysis and manuscript write up. All authors read and approved the final manuscript.

Abstract

Background

The identification of circulating TB strains in the community and drug sensitivity patterns is essential for the tuberculosis control program. This study was undertaken to identify M. tuberculosis strains circulating in selected communities in Ethiopia as well as to evaluate the drug sensitivity pattern of these strains.

Method

This study was a continuation of the Ethiopian National TB Prevalence Survey that was conducted between 2010 and 2011. Culture-positive isolates of M. tuberculosis from previous study were typed using region of difference (RD) 9-based polymerase chain reaction (PCR) and spoligotyping. Drug sensitivity testing was conducted using the indirect proportion method on Lowenstein-Jensen media.

Result

All 92 isolates were confirmed as M. tuberculosis by RD9-based PCR and spoligotyping of 91 of these isolates leds to the identification of 41 spoligotype patterns. Spoligotype revealed higher diversity (45 %) and among this 65.8 % (27/41) were not previously reported. The strains were grouped into 14 clusters consisting of 2–15 isolates. The dominant strains were SIT53, SIT149 and SIT37 consisting of 15, 11, and 9 isolates, respectively. Our study reveals 70 % (64/91) clustered strains and only 39.1 % (25/64) occurred within the same Kebele. Further assignment of the strains to the lineages showed that 74.7 % (68/91) belonged to Euro-American lineage, 18.6 % (17/91) to East Africa Indian lineage and the remaining 6.5 % (6/91) belonged to Indo-oceanic lineage. Valid drug susceptibility test results were available for 90 of the 92 isolates. Mono-resistance was observed in 27.7 % (25/90) and poly-resistance in 5.5 % (5/90) of the isolates. Moreover, multi-drug resistance (MDR-TB) was detected in 4.4 % of the isolates whilst the rest (60/90) were susceptible to all drugs. The highest level of mono-resistance, 26.6 % (24/90), was observed for streptomycin with majority (91.1 %) of streptomycin mono-resistant strains belonging to the Euro-American lineage.

Conclusion

In this study, the strains of M. tuberculosis circulating in selected sites of Ethiopia were identified along with the drug sensitivity patterns. Thus, these findings are useful for the TB Control Program of the country.
Literatur
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