DALHOFF A, HEISIG A, HEISIG P; Interscience Conference on Antimicrobial Agents and Chemotherapy (41st : 2001 : Chicago, Ill.).
Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2001 Dec 16-19; 41: abstract no. C1-146.
Bayer AG, Wuppertal, Germany
BACKGROUND: As quinolones are synthetic drugs, it seems unlikely that quinolone resistance (QR) has emerged by means other than through their frequent use. We investigated whether the QR phenotype and genotype could be selected via non-quinolone agents containing a bicyclic structure common to the quinolones. METHODS: Escherichia coli DSM 10650 was exposed for 7 days to agents demonstrating no antibacterial activity (64 mg/l each): the methylxanthines, caffeine and theophylline; the quinines, chloroquine and primaquine; as well as chinosol, phenprocoumin, allopurinol, quercetin, apigenin and menadion. Nalidixic acid (NAL), ciprofloxacin (CIP), and amoxicillin (AMX)[0.5 X MICs] served as controls. Bacteria were transfered daily on to fresh brain heart infusion medium (37 C). QR was screened for by quantitating the MICs daily for NAL, CIP and AMX either in the presence or absence of reserpine. Mutations in the QR-determining region (QRDR) of gyrA and parC were DNA sequenced. RESULTS: For all non-antibiotics tested, a continuous increase in NAL MICs from 1 mg/l on day 0 up to 8 to > 32 mg/l on day 7 were observed. The MICs for CIP and AMX remained unchanged. Excepting the quinines, subculturing for 24h in drug-free media resulted in a decrease in NAL MICs to pre-incubation values. NAL MICs remained (>32 mg/l) upon subculture in quinine-free medium. Sequence analysis of the QRDR revealed that all the mutants had mutations in gyrA 87 (aspartate to glycin). CIP MICs of these mutants rose from
Publication Types:
Keywords:
- Anti-Bacterial Agents
- Base Sequence
- Ciprofloxacin
- Microbial Sensitivity Tests
- Mutation
- Nalidixic Acid
- Quinolones
- Selection (Genetics)
- genetics
Other ID:
UI: 102270347
From Meeting Abstracts