title: Evidence that phosphate specific transporter is amplified in a fluoroquinolone resistant Mycobacterium smegmatis.
abstract: We reported in an earlier study that active efflux of drug has a predominant role in conferring resistance in a laboratory-generated ciprofloxacin-resistant mutant of Mycobacterium smegmatis. This mutant exhibited mRNA level overexpression, as well as chromosomal amplification, of the gene pstB, encoding the putative ATPase subunit of phosphate specific transport (Pst) system. We demonstrate here that this mutant shows enhanced phosphate uptake and that inactivation of pstB in the parental strain results in loss of high affinity phosphate uptake and hypersensitivity to fluoroquinolones. These findings suggest a novel role of the Pst system in active efflux, in addition to its involvement in phosphate transport.
authors.affiliation: Institute of Microbial Technology, Chandigarh, India.
authors.forename: K
authors.initials: K
authors.lastname: Bhatt
authors.forename: S K
authors.initials: SK
authors.lastname: Banerjee
authors.forename: P K
authors.initials: PK
authors.lastname: Chakraborti
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000251:Adenosine Triphosphatases; D000890:Anti-Infective Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics*; D001692:Biological Transport; D002939:Ciprofloxacin / Q000493:pharmacokinetics / Q000494:pharmacology*; D020102:Mycobacterium smegmatis / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*
chemical_list: D018528:ATP-Binding Cassette Transporters; D000890:Anti-Infective Agents; D001426:Bacterial Proteins; D010710:Phosphates; D002939:Ciprofloxacin; D000251:Adenosine Triphosphatases; C120060:phosphate import ATP-binding protein, Bacteria