Heteroresistance to meropenem in carbapenem-susceptible Acinetobacter baumannii.
J Clin Microbiol
; 47(12): 4055-9, 2009 Dec.
Article
em En
| MEDLINE
| ID: mdl-19828742
ABSTRACT
The characteristics of carbapenem heteroresistance were studied in 14 apparently carbapenem-susceptible Acinetobacter baumannii isolates. The MICs for carbapenems were determined, and the isolates were genotyped by pulsed-field gel electrophoresis (PFGE) and sequence typing (ST). Population analysis, testing of the stability of the heteroresistant subpopulations, and time-killing assays were performed. The agar dilution MICs of both imipenem and meropenem for the native isolates ranged from 0.25 to 4 mg/liter. The isolates belonged to nine PFGE types and exhibited seven ST allelic profiles. Population analysis revealed subpopulations that grew in the presence of imipenem at concentrations of up to 8 mg/liter and meropenem at concentrations of up to 32 mg/liter. The meropenem-heteroresistant subpopulations of 11 isolates exhibited stable resistance with MICs that ranged from 16 to >32 mg/liter; their PFGE profiles were identical to those of the native isolates. Time-kill assays with meropenem revealed less pronounced killing for 10 isolates. These findings indicate that meropenem pressure can produce meropenem-heteroresistant subpopulations that might subsequently select for highly resistant strains.
Texto completo:
1
Bases de dados:
MEDLINE
Assunto principal:
Carbapenêmicos
/
Tienamicinas
/
Farmacorresistência Bacteriana Múltipla
/
Acinetobacter baumannii
/
Antibacterianos
Limite:
Humans
País/Região como assunto:
Europa
Idioma:
En
Revista:
J Clin Microbiol
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Grécia