The role of chemotherapy in polymorphonuclear phagocytosis in pneumonia.

The efficacy of the host defense system is a determining factor for the outcome of antimicrobial events in infected patients. The neutrophil granulocyte plays a key role in the lung's defense against bacterial invasion and in the absence of a sufficient attraction of functionally intact neutrophils in the lung, following bacterial challenge, severe pulmonary infection may result. The involvement of phagocytes in pneumonia is well known: infiltration of lung parenchyma by neutrophils occurs within a short time in response to infection and is followed by an influx of monocytes. We investigated the effects of antimicrobial therapy in pneumonia on polymorphonuclear neutrophil (PMN) phagocytosis.

Bacterial adherence in smokers and non-smokers.

Bacterial adherence is thought to be a first important step in the pathogenesis of infection. It is now recognized that bacteria bind to and colonize mucosal surfaces in a highly selective manner via a lock- and key mechanism with complementary receptors on the mucosal surfaces of the host. We studied adherence to buccal cells of a panel of potential respiratory pathogens as Staphylococcus aureus, Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa in 18 smokers and 18 healthy non-smokers. Our results show an increased pneumococcal adherence in smokers compared to that of non-smokers and this may explain the role of smoking as a risk factor in the susceptibility to bacterial pneumonia. The other bacterial species tested do not differ in their adhesion values and probably require previous damage of the mucosa before adhesion 1997 The Italian Pharmacological Society.

Inhibition of bacterial adhesion by sub-inhibitory concentrations: brodimoprim vs trimethoprim.

There is accumulating evidence that sub-inhibitory concentrations (sub-MICs) of many antibiotics are not without effect on bacteria and even though they do not kill bacteria, they are still able to interfere with some important aspects of bacterial cell function. The aim of the present study was to investigate the effect of sub-MICs of brodimoprim and trimethoprim on Escherichia coli and Staphylococcus aureus adhesiveness to human mucosal cells. Sub-MICs of brodimoprim down to 1/32 MIC (0.03 microgram/ml) significantly reduced the E. coli adhesion to human buccal epithelial cells and this inhibition was significantly higher than the corresponding pattern for trimethoprim. Adhesion of S. aureus was significantly reduced down to 1/16 MIC for both brodimoprim and trimethoprim but no significant differences resulted between the two patterns. 2,4 Diaminopyrimidines and related structures have a high affinity for the enzyme dihydrofolate reductase and this causes a reduction in the synthesis of essential purines, thus reducing also DNA and the synthesis or expression of surface adhesins.