Biomaterial Database

In vitro selection of Escherichia coli mutants with decreased susceptibility to norfloxacin. 1988

A Forsgren, and A C Striby

Department of Medical Microbiology, University of Lund, Malmö General Hospital, Sweden.

In 10 clinical isolates of Escherichia coli the frequency of spontaneous mutation to high levels of resistance to nalidixic acid was greater than 300-fold higher than that to norfloxacin. Norfloxacin resistant mutants could not be detected (mutation frequency: less than 10(-12). However, nalidixic acid resistant mutants of E. coli developed decreased susceptibility to norfloxacin at a rate of approximately 10(-9). Mutants with decreased susceptibility to norfloxacin could also be obtained when the same clinical isolates of E. coli were exposed to norfloxacin in 2 steps. However, mutants with MIC values greater than 8 micrograms/ml for norfloxacin were never obtained even after repeated exposure. Widespread use of cinoxacin or nalidixic acid may select resistant strains and reduce the efficacy of norfloxacin and other 4-quinolones.

UI	MeSH Term	Description	Entries
D009154	Mutation	Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.	Mutations
D009268	Nalidixic Acid	A synthetic 1,8-naphthyridine antimicrobial agent with a limited bacteriocidal spectrum. It is an inhibitor of the A subunit of bacterial DNA GYRASE.	Nalidixin,Nalidixate Sodium,Nalidixate Sodium Anhydrous,Nevigramon,Sodium Nalidixic Acid, Anhydrous,Sodium Nalidixic Acid, Monohydrate,Acid, Nalidixic,Anhydrous, Nalidixate Sodium,Sodium Anhydrous, Nalidixate,Sodium, Nalidixate
D009643	Norfloxacin	A synthetic fluoroquinolone (FLUOROQUINOLONES) with broad-spectrum antibacterial activity against most gram-negative and gram-positive bacteria. Norfloxacin inhibits bacterial DNA GYRASE.	AM-0715,AM-715,MK-0366,MK-366,MK0366,MK366,Noroxin,AM 0715,AM 715,AM0715,MK 0366,MK 366
D004352	Drug Resistance, Microbial	The ability of microorganisms, especially bacteria, to resist or to become tolerant to chemotherapeutic agents, antimicrobial agents, or antibiotics. This resistance may be acquired through gene mutation or foreign DNA in transmissible plasmids (R FACTORS).	Antibiotic Resistance,Antibiotic Resistance, Microbial,Antimicrobial Resistance, Drug,Antimicrobial Drug Resistance,Antimicrobial Drug Resistances,Antimicrobial Resistances, Drug,Drug Antimicrobial Resistance,Drug Antimicrobial Resistances,Drug Resistances, Microbial,Resistance, Antibiotic,Resistance, Drug Antimicrobial,Resistances, Drug Antimicrobial
D004926	Escherichia coli	A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.	Alkalescens-Dispar Group,Bacillus coli,Bacterium coli,Bacterium coli commune,Diffusely Adherent Escherichia coli,E coli,EAggEC,Enteroaggregative Escherichia coli,Enterococcus coli,Diffusely Adherent E. coli,Enteroaggregative E. coli,Enteroinvasive E. coli,Enteroinvasive Escherichia coli
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man