Variation in Mutant Prevention Concentrations

Mutant prevention concentrations of four carbapenems against gram-negative rods.

We tested the propensities of four carbapenems to select for resistant Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii mutants by determining the mutant prevention concentrations (MPCs) for 100 clinical strains with various ss-lactam phenotypes. Among the members of the Enterobacteriaceae family and A. baumannii strains, the MPC/MIC ratios were mostl...

Mutant prevention concentrations of ciprofloxacin for urinary tract infection isolates of Escherichia coli.

OBJECTIVES To measure the mutant prevention concentration (MPC) of ciprofloxacin for a set of urinary tract infection (UTI) Escherichia coli isolates with different levels of susceptibility and determine whether MPC can be predicted from MIC. METHODS MPC was defined as the lowest ciprofloxacin concentration that prevented the growth of resistant colonies when 10(10) bacteria were spread on so...

Relationships between mutant prevention concentrations and mutation frequencies against enrofloxacin for avian pathogenic Escherichia coli isolates.

Clinical efficacies of mutant prevention concentration (MPC) and mutant selection window (MSW) hypotheses have been evaluated for human clinical isolates. We tested the MSW hypothesis by evaluating the relationships between MPCs and mutation frequencies against enrofloxacin for avian pathogenic Escherichia coli (APEC) isolates. Mutation frequencies of strains with MPC:MIC ratios of 8 to 16 were...

Mutant Prevention Concentrations of Imipenem and Meropenem against Pseudomonas aeruginosa and Acinetobacter baumannii

The aim of this study was to determine the usefulness of the MPC of carbapenems against clinical isolates of Pseudomonas spp. and Acinetobacter spp. and to assess its possible relationship with mechanisms of resistance. Detection of the mechanisms of resistance was performed using Antibiotic Susceptibility Testing, Double Disk Synergy, disk antagonism, addition of NaCl to the medium, addition o...

Semen characteristics sexual behavior and variation of serum testosterone concentrations in caspian ponies