The use of a tissue culture model to assess the penetration of antibiotics into epithelial cells

A tissue culture model was developed in which enteroinvasive Escherichia coli invaded and survived within HEp-2 epithelial cells. The bacteria were shown to be intracellular by light and electron microscopy and immunofluorescence. The model was then used to assess the ability of antimicrobial agents to penetrate into cells and alter the morphology of the bacteria. Chloramphenicol, tetracycline, trimethoprim and ciprofloxacin penetrated more easily than /?-lactam antibiotics. Ampicillin and its derivatives penetrated more easily than cephalosporins, latamoxef or aztreonam. Only ciprofloxacin was able to kill intracellular bacteria