Infect Chemother.  2006 Dec;38(6):344-348.

Mutant Prevention Concentration of Polymyxin B for the Clinical Isolates of Pseudomonas aeruginosa

Affiliations
  • 1Division of Infectious Diseases, College of Medicine, Hanyang University, Seoul, Korea. paihj@hanyang.ac.kr

Abstract

BACKGROUND: Infection caused by multi-drug resistant (MDR) Gram-negative organisms such as Pseudomonas and Acinetobacter species is one of emerging important problems in modern hospitals. To treat multi-drug resistant non-fermenting Gram-negatives, polymyxins which were used in 1960s, but abandoned because of grave toxicities such as renal toxicity are reused. The objective of this study was to estimate the probability of resistance development of the clinical isolates of Pseudomonas aeruginosa to polymyxins.
METHODS
AND MATERIALS: Twenty-nine multidrug-resistant P. aeruginosa isolates were collected from Dankook University Hospital and Seoul National University Hospital in 2000 and tested for antimicrobial susceptibility test, minimal inhibitory concentration (MIC), mutant prevention concentration (MPC) and mutant frequency to ciprofloxacin and polymyxin B.
RESULTS
The MIC50 and MIC90 of polymyxin B for the isolates were 2 and 2 microgram/mL, and those of ciprofloxacin were 0.5 and 4 microgram/mL, respectively. Thirteen of 29 isolates developed polymyxin B-resistant mutants but all 29 isolates, ciprofloxacin-resistant mutants. The MPC50 and MPC90 of polymyxin B were 32 and 64 microgram/mL, and those values of ciprofloxacin were 4 and 64 microgram/mL. Mutation frequencies of polymyxin B ranged from 2 x 10(-9) to 2 x 10(-7), and those of ciprofloxacin from 4 x 10(-10) to 5 x 10(-7).
CONCLUSIONS
Mutation frequencies of polymyxin B were similar to those of ciprofloxacin, suggesting appreciable development of resistant mutants with wide usage of polymyxins.

Keyword

Pseudomonas aeruginosa; Polymyxin B; Mutant prevention concentration; Mutant frequency

MeSH Terms

Acinetobacter
Ciprofloxacin
Mutation Rate
Polymyxin B*
Polymyxins*
Pseudomonas aeruginosa*
Pseudomonas*
Seoul
Ciprofloxacin
Polymyxin B
Polymyxins
Full Text Links
  • IC
Actions
Cited
CITED
export Copy
Close
Share
  • Twitter
  • Facebook
Similar articles
Copyright © 2024 by Korean Association of Medical Journal Editors. All rights reserved.     E-mail: koreamed@kamje.or.kr