POSTANTIBIOTIC EFFECTS OF IMIPENEM AND ENOXACIN AGAINST SALMONELLA-TYPHIMURIUM AND SALMONELLA-ENTERITIDIS AND THE INFLUENCE ON THEIR SURFACE HYDROPHOBICITY

The influence of the postantibiotic effect (PAE) and the postantibioti c sub-MICs effect (PA SME) of imipenem and enoxacin on the surface hyd rophobicity of S. typhimurium and S. enteritidis strains were studied by evaluating Congo red binding and the aggregation in molar solutions of ammonium sulfate (SAT). A PAE was induced by 2x and 4x MIC of anti biotics tested for 0.5 h. Suprainhibitory concentrations of imipenem a gainst S. typhimurium induced a short PAE (0.3-0.6 h) compared to S. e nteritidis (6.0-9.7 h). Suprasubinhibitory concentrations of imipenem did not allow a regrowth of S. enteritidis. Similar results were also found for enoxacin. Evaluation of surface hydrophobic properties of th e salmonellas after affecting both PAEs and PA SMEs has shown that imi penem at concentrations 4xMIC and 4xMIC + 0.3xMIC partially influenced the hydrophobicity of S. typhimurium. S. enteritidis was more suscept ible toward both antibiotics tested.