Changes in serum sensitivity and hydrophobicity in a clinical isolate of Klebsiella pneumoniae treated with subinhibitory concentrations of aminoglycosides.
The effects of subinhibitory concentrations (sub-MICs) of gentamicin, netilmicin and amikacin on the serum sensitivity and the cell surface hydrophobicity of Klebsiella pneumoniae were investigated. At concentrations 1/16 or 1/8 of the MICs, in all antibiotics significantly enhanced the sensitivity of K. pneumoniae to human serum as compared to nontreated bacteria. The higher concentration of the antibiotics tested was more efficient. Survival of bacteria under these conditions ranged from 24.1% to 36.7% after incubation with 10% serum for 180 min when compared with the viability of the control bacteria. Bacteria grown with the test antibiotics at sub-MICs (1/8 or 1/4 of the MICs) manifested an effective decrease of the surface hydrophobicity. The aminoglycosides which were more effective at a concentration of 1/4 of the MICs reduced bacterial hydrophobicity to 28.5% (gentamicin), 14.8% (netilmicin) and 12.7% (amikacin) of the nontreated bacteria.
Hostacká
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Institute of Preventive and Clinical Medicine, Bratislava, Slovakia.
D000583:Amikacin / Q000008:administration & dosage / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001422:Bacterial Adhesion; D001770:Blood Bactericidal Activity; D005839:Gentamicins / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D007710:Klebsiella Infections / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000302:isolation & purification / Q000502:physiology; D008826:Microbial Sensitivity Tests; D009428:Netilmicin / Q000008:administration & dosage / Q000494:pharmacology; D012137:Respiratory System / Q000382:microbiology; D013499:Surface Properties