Influence on Enterobacter cloacae metabolism, cell-surface hydrophobicity and motility of suprainhibitory concentrations of carbapenems.
The impact of postantibiotic effect (PAE) of carbapenems (imipenem, meropenem) on the metabolism (biosynthesis of macromolecules, respiration), cell-surface hydrophobicity and motility of a clinical isolate of Enterobacter cloacae was examined. The metabolism was evaluated after 16 h and after 1 d of cultivation using 2x and 4x minimum inhibitory concentrations (MIC) of both antibiotics for the induction of PAE. Imipenem at 4 x MIC did not induce PAE. After a 16-h cultivation (in the postantibiotic phase of both carbapenems), inhibition of nucleosynthesis and protein synthesis was found; after a 1-d cultivation, during regrowth stimulation of mainly 14C-leucine incorporation was found. The presence of the exogenous intermediates of citrate cycle, viz. 2-oxoglutarate, increased the respiratory activity of the cells. The cell-surface hydrophobicity (evaluated by three methods--bacterial adhesion to hydrocarbon, nitrocellulose-filter test and salt-aggregation test) decreased after PAE of both carbapenems; meropenem was more effective. Motility (an important virulence factor) was inhibited in the postantibiotic phase of both carbapenems; the 4 x MIC caused a higher inhibition.
Majtán
V
V
Institute of Preventive and Clinical Medicine, 833 01 Bratislava, Slovakia.
Majtánová
L
L
D015780:Carbapenems / Q000494:pharmacology*; D016972:Enterobacter cloacae / Q000737:chemistry / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D015378:Imipenem / Q000494:pharmacology*; D000077731:Meropenem; D009068:Movement / Q000187:drug effects; D013845:Thienamycins / Q000494:pharmacology*; D013997:Time Factors
D015780:Carbapenems; D013845:Thienamycins; D015378:Imipenem; D000077731:Meropenem