Mechanisms of clinical resistance to fluoroquinolones in Staphylococcus aureus.

Article Details

Citation

Copy to clipboard

Nakanishi N, Yoshida S, Wakebe H, Inoue M, Yamaguchi T, Mitsuhashi S

Mechanisms of clinical resistance to fluoroquinolones in Staphylococcus aureus.

Antimicrob Agents Chemother. 1991 Dec;35(12):2562-7.

PubMed ID

1667255 [ View in PubMed

]

Abstract

Mechanisms of Staphylococcus aureus resistance to fluoroquinolones were characterized. Subunit A and B proteins of DNA gyrase were partially purified from fluoroquinolone-susceptible strain SA113 and resistant isolate MS16405, which was 250- to 1,000-fold less susceptible to fluoroquinolones such as ciprofloxacin, norfloxacin, ofloxacin, temafloxacin, and sparfloxacin than SA113 was. The supercoiling activity of the gyrase from SA113 was inhibited by the fluoroquinolones, and the 50% inhibitory concentrations of the drugs correlated well with their MICs. In contrast, the gyrase from MS16405 was insensitive to inhibition of supercoiling by all of the quinolones tested, even at 800 micrograms/ml. Combinations of heterologous gyrase subunits showed that subunit A from MS16405 conferred fluoroquinolone resistance, suggesting that an alteration in gyrase subunit A is a cause of the fluoroquinolone resistance in MS16405. Uptake of hydrophilic fluoroquinolones such as ciprofloxacin and norfloxacin by MS16405 was significantly lower than that by SA113. Furthermore, this difference was abolished by the addition of an energy inhibitor, carbonyl cyanide m-chlorophenylhydrazone, suggesting that an alteration in an energy-dependent process, such as an active efflux of hydrophilic quinolones, may lead to decreased drug uptake and hence to increased resistance to fluoroquinolones in MS16405. These findings suggest that the fluoroquinolone resistance in MS16405 is due mainly to an alteration in subunit A of DNA gyrase and may also be associated with an alteration in the drug uptake process.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Temafloxacin	DNA gyrase subunit A	Protein	Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)	Yes	Inhibitor	Details
Temafloxacin	DNA topoisomerase 4 subunit A	Protein	Haemophilus influenzae (strain ATCC 51907 / DSM 11121 / KW20 / Rd)	Yes	Inhibitor	Details