Development of a novel method for assessing drug resistances using recombinant mycobacteria

• Project/Area Number: 26461173
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Respiratory organ internal medicine
• Research Institution: National Institute of Infectious Diseases
• Principal Investigator: Nakata Noboru 国立感染症研究所, ハンセン病研究センター 感染制御部, 主任研究官 (70237296)
• Co-Investigator(Kenkyū-buntansha): 星野 仁彦 国立感染症研究所, ハンセン病研究センター 感染制御部, 室長 (20569694)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Project Status: Completed (Fiscal Year 2016)
• Budget Amount: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2015: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2014: ¥1,950,000 (Direct Cost: ¥1,500,000、Indirect Cost: ¥450,000)
• Keywords: 薬剤耐性 / 抗酸菌 / MAC / Mycobacterium avium / Mycobacterium / drug resistance / M. avium complex / MIC / rifampicin

Outline of Final Research Achievements

Drug susceptibilities of 50 Mycobacterium avium clinical isolates obtained from untreated patients were examined. Resistance rates of rifampicin, levofloxacin, clarithromycin were 52%, 68%, and 6%, respectively. No non-synonymous mutations were detected in RRDR of the rpoB gene and QRDR of the gyrA gene of the drug resistant isolates. Clarithromycin resistance of the isolates was also analyzed. No mutation were found in the rrl genes of the clarithromycin-resistant isolates. To test whether mutations in the rpoB other than RRDR and in the gyrA other than QRDR in the drug resistant isolates are responsible for their resistance, recombinant M. smegmatis strains, having the rpoB gene or gyrBA genes from the drug resistant M. avium isolates instead of M. smegmatis rpoB or gyrBA, were produced and their drug susceptibilities were examined. Results revealed that rifampicin resistance and quinolone resistance of the M. avium isolates were not caused by mutations in the rpoB and gyrA genes.

Research Products

• [Presentation] Analysis of fluoroquinolone susceptibility and temperature sensitivity of the Mycobacterium leprae DNA gyrase (2017)
  • Author(s): Noboru Nakata, Mitsunori Yoshida, Yoshihiko Hoshino
  • Organizer: 日本細菌学会
  • Place of Presentation: 宮城県仙台市
  • Year and Date: 2017-03-19
• [Presentation] A novel method for assessing Mycobacterium tuberculosis gyrBA mutations and fluoroquinolone resistance (2017)
  • Author(s): Mitsunori Yoshida, Yoshihiko Hoshino, Noboru Nakata
  • Organizer: 日本細菌学会
  • Place of Presentation: 宮城県仙台市
  • Year and Date: 2017-03-19
• [Presentation] Analysis of mycobacterial rrl genes and macrolide resistance using recombinant M. smegmatis. (2015)
  • Author(s): Noboru Nakata, Masanori Kai, and Masahiko Makino
  • Organizer: 第88回日本細菌学会総会
  • Place of Presentation: 岐阜県岐阜市長良川国際会議場
  • Year and Date: 2015-03-27 – 2015-03-28