Tuberc Respir Dis.  2017 Jul;80(3):270-276. 10.4046/trd.2017.80.3.270.

Frequency and Type of Disputed rpoB Mutations in Mycobacterium tuberculosis Isolates from South Korea

• Jo KW
• Lee S
• Kang MR
• Sung H
• Kim MN
• Shim TS

• KMID: 2385042
• DOI: http://doi.org/10.4046/trd.2017.80.3.270

Abstract

BACKGROUND
A disputed rpoB mutation is a specific type of rpoB mutation that can cause low-level resistances to rifampin (RIF). Here, we aimed to assess the frequency and types of disputed rpoB mutations in Mycobacterium tuberculosis isolates from South Korea.
METHODS
Between August 2009 and December 2015, 130 patients exhibited RIF resistance on the MTBDRplus assay at Asan Medical Center. Among these cases, we identified the strains with disputed rpoB mutation by rpoB sequencing analysis, as well as among the M. tuberculosis strains from the International Tuberculosis Research Center (ITRC).
RESULTS
Among our cases, disputed rpoB mutations led to RIF resistance in at least 6.9% (9/130) of the strains that also exhibited RIF resistance on the MTBDRplus assay. Moreover, at the ITRC, sequencing of the rpoB gene of 170 strains with the rpoB mutation indicated that 23 strains (13.5%) had the disputed mutations. By combining the findings from the 32 strains from our center and the ITRC, we identified the type of disputed rpoB mutation as follows: CTG511CCG (L511P, n=8), GAC516TAC (D516Y, n=8), CTG533CCG (L533P, n=8), CAC526CTC (H526L, n=4), CAC526AAC (H526N, n=3), and ATG515GTG (M515V, n=1).
CONCLUSION
Disputed rpoB mutations do not seem to be rare among the strains exhibiting RIF resistance in South Korea.

Keyword

Rifampin; Biological Assay; Mycobacterium tuberculosis; rpoB protein, Mycobacterium tuberculosis; Mutation

MeSH Terms

Biological Assay
Chungcheongnam-do
Humans
Korea*
Mycobacterium tuberculosis*
Mycobacterium*
Rifampin
Tuberculosis
Rifampin

Figure

• 

  Figure 1 Study flow chart. DST: drug susceptibility test; NTM: non-tuberculous mycobacteria; AFB: acid-fast bacillus; RIF: rifampin.

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