Detection and prevalence of active drug efflux mechanism in various multidrug-resistant Klebsiella pneumoniae strains from Turkey.
The prevalence of active drug efflux pump and porin alterations was investigated in Turkish nosocomial strains of Klebsiella pneumoniae exhibiting a multidrug-resistant phenotype. MICs of various antibiotics, including quinolones, chloramphenicol, tetracycline, and beta-lactams, for those strains were determined either with or without the efflux pump inhibitor phenylalanine arginine beta-naphthylamide (PAbetaN). Thirty-nine percent of the strains exhibited a PAbetaN-modulated resistance for quinolones, chloramphenicol, and tetracycline. In these strains, a significant increase of chloramphenicol accumulation was gained in the presence of the efflux pump inhibitor PAbetaN or with the energy uncoupler carbonyl cyanide m-chlorophenylhydrazone. Moreover, high-level expression of the membrane fusion protein AcrA, which was immunodetected in most of those isolates, suggests that the AcrAB/TolC efflux machinery contributed to their antibiotic resistance. Studies of K. pneumoniae porins indicated that the majority of the strains, including extended-spectrum beta-lactamase producers and efflux-positive ones, presented an alteration in their sorbitol-sensitive porin (OmpK35) expression. This is the first report showing the prominent role of active drug efflux in the antibiotic resistance of nosocomial K. pneumoniae strains from Turkey.
Hasdemir
Ufuk Over
UO
Department of Microbiology, School of Medicine, Marmara University, Istanbul, Turkey.
Chevalier
Jacqueline
J
Nordmann
Patrice
P
Pagès
Jean-Marie
JM
D001425:Bacterial Outer Membrane Proteins / Q000032:analysis; D001426:Bacterial Proteins / Q000032:analysis; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002701:Chloramphenicol / Q000378:metabolism; D024901:Drug Resistance, Multiple, Bacterial; D029968:Escherichia coli Proteins / Q000032:analysis; D006867:Hydrolases / Q000032:analysis; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D018272:Porins / Q000032:analysis
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C119261:OmpK35 porin, Klebsiella pneumoniae; D018272:Porins; C482905:OmpX protein, E coli; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D002701:Chloramphenicol; D006867:Hydrolases