A comparative study of the in-vitro activity of cefepime and other antimicrobial agents against penicillin-susceptible and penicillin-resistant Streptococcus pneumoniae.

Using the national surveillance programme of USA hospitals, we selected 162 strains of Streptococcus pneumoniae for sensitivity testing using the NCCLS breakpoints for benzylpenicillin and the oxacillin discs screen test. Included in the group of isolates were 85 relatively penicillin-resistant and 33 penicillin-resistant strains. The activity of cefepime, a new cephalosporin, was compared with other cephalosporins and penicillins as well as some non-beta-lactam antimicrobials. Imipenem was the most active agent but, cefepime, cefotaxime, ceftriaxone and ciprofloxacin were only slightly less active. The least active agents were ceftazidime, cefuroxime, piperacillin/tazobactam and ticarcillin/clavulanate. Cefepime is a potential alternative treatment to penicillin, particularly when penicillin-resistant and relatively penicillin-resistant S. pneumoniae are encountered. The clinical importance of screening for penicillin resistance by the use of the oxacillin disc is emphasized.

In-vitro activity of cefepime and other antimicrobials: survey of European isolates.

Cefepime, a new cephalosporin which has a broad-spectrum of activity was tested in vitro against 1961 Gram-positive and Gram-negative clinical isolates obtained from European hospitals. Cefepime was highly active against Gram-negative organisms, inhibiting over 94% of strains tested. The overall susceptibility rate for cefepime against all isolates was 81%. Cefepime was more active than any of the third-generation cephalosporins tested against species capable of producing type I beta-lactamases, e.g. Enterobacter cloacae, Citrobacter freundii, and Enterobacter aerogenes. The activity of cefepime against Pseudomonas aeruginosa was similar to that of ceftazidime and substantially greater than those of cefotaxime and ceftriaxone. All cephalosporins except ceftazidime exhibited high activity against methicillin-susceptible Staphylococcus aureus but poor activity was observed against methicillin-resistant strains. Overall susceptibility to cefepime is lower in Europe than it is in North America.

Activity of pirlimycin against pathogens from cows with mastitis and recommendations for disk diffusion tests.

Pirlimycin is an analog of clindamycin that will be recommended for therapy of bovine mastitis. It has good activity against staphylococci and streptococci, the major pathogens for bovine mastitis. Five hundred and thirty bacterial isolates recovered from cows with mastitis were studied to confirm the spectrum of activity and to develop recommendations for susceptibility testing. Pirlimycin is not active against isolates of Enterobacteriaceae, it varies in its activity against enterococci, and it is active against veterinary isolates of streptococci (MIC for 50% of strains tested, < or = 0.03 to 0.06 microgram/ml) and staphylococci (MIC for 50% of strains tested, 0.25 to 1.0 microgram/ml). On the basis of levels of drug attained in the milk with recommended dosing schedules, we chose MIC breakpoints of < or = 2 micrograms/ml for susceptibility and > or = 4 micrograms/ml for resistance. We also recommended a disk diffusion test using a disk containing 2 micrograms/ml and breakpoints of < or = 12 mm for resistance and > or = 13 mm for susceptibility.