Comparative analysis of the antimicrobial action of polymorphonuclear leucocytes in vitro, ex vivo and in vivo

A comparative study on the phagocytic capacity of human and rat polymorphonuclear leucocytes was performed. The activity of rat leucocytes was assessed by using the rat polyvinyl sponge model and the granuloma pouch model. Isolated human leucocytes were either suspended in buffer or homologous serum. Assessments of the susceptibility of Pseudomonas aeruginosa or Klebsiella pneumoniae to the antimicrobial action of leucocytes revealed that the activity of normal human leucocytes and rat leucocytes was very similar, whereas human leucocytes obtained from chronically infected patients were significantly more active. Pretreatment of the bacteria with subinhibitory mezlocillin and azlocillin concentrations with or without immunoglobulin G rendered the bacteria more susceptible to the antimicrobial action of both types of leucocytes. Again results obtained by the different methods were very similar.