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Role of an ABC importer in mycobacterial drug resistance

P K Chakraborti1, K Bhatt, S K Banerjee

  • 1Institute of Microbial Technology, Chandigarh, India. pradip@koel.imtech.ernet.in

Bioscience Reports
|December 10, 1999
PubMed

Insights

Amplification of the phosphate specific transporter (Pst) in Mycobacterium smegmatis correlated with high-level fluoroquinolone resistance. This suggests Pst may play a role in antibiotic resistance, independent of phosphate transport.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Bacterial Physiology

Background:

  • The phosphate specific transporter (Pst) is a bacterial ABC transporter system.
  • Pst facilitates phosphate uptake, primarily at low phosphate concentrations.

Purpose of the Study:

  • To investigate the role of the Pst system in antibiotic resistance.
  • To determine if Pst amplification contributes to fluoroquinolone resistance in Mycobacterium smegmatis.

Main Methods:

  • Generation of a laboratory ciprofloxacin-resistant Mycobacterium smegmatis colony (CIPr).
  • Analysis of Pst transporter gene amplification in CIPr.
  • Culturing bacteria under conditions where phosphate scavenging is inoperative.

Main Results:

  • Observed amplification of the Pst transporter in a ciprofloxacin-resistant Mycobacterium smegmatis strain.
  • This amplification occurred under conditions where the phosphate transport function of the operon was not active.
  • The results suggest a link between Pst amplification and high-level fluoroquinolone resistance.

Conclusions:

  • The phosphate specific transporter (Pst) system may contribute to high-level fluoroquinolone resistance in Mycobacterium smegmatis.
  • Pst's role in resistance appears independent of its canonical phosphate import function.
  • Further research is warranted to elucidate the mechanism of Pst in antibiotic resistance.

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