TREATMENT OF SEVERE INFECTIONS CAUSED BY PENICILLIN-RESISTANT PNEUMOCOCCI - ROLE OF 3RD-GENERATION CEPHALOSPORINS

Penicillin resistance occurred soon after the discovery of penicillin, first in the test tube and;subsequently in patients, The prevalence o f invasive pneumococcal disease has been estimated to be as high as 15 -18/100,000 in the elderly population and even higher in AIDS patients , children and the very old. While prevention with pneumococcal. vacci ne seems the most reasonable solution, under-utilization of the vaccin e and an increase in the number of immuno-compromised individuals:has limited the success of this approach. Streptococcus pneumoniae is conv entionally classified as penicillin-susceptible (MIC < 0.125 mg/l), pe nicillin-intermediate (MIC 0.125-1.0 mg/l) and penicillin-resistant (M IC greater than or equal to 2 mg/l). In many countries, penicillin res istance in pneumococci is on the increase and in some areas penicillin intermediate and resistant isolates reach 60%. As a consequence, a sw itch of therapy from penicillin to other agents is mandatory in infect ions caused by penicillin-resistant strains. Benzyl-penicillin, howeve r, can be used for most infections caused by penicillin-intermediate a nd all infections caused by penicillin-sensitive strains, Third genera tion cephalosporins, and in particular cefotaxime, are an optional alt ernative,. particularly in view of their low MICs against penicillin-s usceptible and -intermediate and some penicillin-resistant strains, an d the easily achievable therapeutic concentrations in serum, pulmonary tissues and other compartments in which pneumococcal infections occur . Third generation cephalosporins have a high safety record and can be administered to children, pregnant women and the elderly. Their relat ively low price is an important aspect. Ceftazidime and ceftizoxine sh ould not be used, however, because of their high MICs against penicill in resistant strains.