Serum sensitivity and cell surface hydrophobicity of Klebsiella pneumoniae treated with gentamicin, tobramycin and amikacin.
A suppression of bacterial growth of Klebsiella pneumoniae after 30 min treatment with gentamicin, tobramycin and amikacin at suprainhibitory concentrations was found (postantibiotic effect, PAE). The antibiotics at a concentration of 2 x MIC induced PAEs in the range of 0.5-1.7 h, PAEs manifested by aminoglycosides at a concentration of 4 x MIC varied between 0.8-3.3 h. Susceptibility of exposed bacteria to serum bactericidal activity was efficiently enhanced compared with controls (without antibiotics). A survival of treated bacteria was between 12.7-36.6% (2 x MIC) or 5.0-8.3% (4 x MIC). The percentage of viable nontreated bacteria moved between 70.2-83.0% at these conditions. Surface hydrophobicity of bacteria exposed to aminoglycosides was only slightly increased. The results indicate that exposure of K. pneumoniae to a suprainhibitory concentrations of aminoglycosides in vitro enhanced the susceptibility of this strain to human serum bactericidal activity. Whether this phenomenon occurs in vivo, remains to be determined.
Hostacká
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Institute of Preventive and Clinical Medicine, Department of General Microbiology, Bratislava, Slovakia.
D000583:Amikacin / Q000008:administration & dosage / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001681:Biological Assay; D001782:Blood Donors; D005839:Gentamicins / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D007711:Klebsiella pneumoniae / Q000187:drug effects* / Q000254:growth & development*; D008826:Microbial Sensitivity Tests; D015610:Serum Bactericidal Test; D014031:Tobramycin / Q000008:administration & dosage / Q000494:pharmacology
D000900:Anti-Bacterial Agents; D005839:Gentamicins; D000583:Amikacin; D014031:Tobramycin