The in-vitro activity of CP-62,993 against Haemophilus influenzae, Branhamella catarrhalis, staphylococci and streptococci.
The in-vitro activity of a new macrolide antibiotic CP-62,993 (Pfizer Ltd) was determined for 420 bacterial isolates, comprising 150 Haemophilus influenzae, 48 Branhamella catarrhalis, 50 Staphylococcus aureus, 50 coagulase negative staphylococci, 50 beta-haemolytic streptococci, 50 Streptococcus pneumoniae and 22 oral streptococci. CP-62,993 was compared with erythromycin and penicillin (ampicillin in the case of H. influenzae). The MICs of CP-62,993 were found to be lower than those of erythromycin for the two Gram-negative species tested: this was particularly marked in the case of H. influenzae where a ten-fold difference in the MIC50 was observed (CP-62,993, 0.25 mg/l, erythromycin 2 mg/l). In general MICs of CP-62,993 were two-fold higher than those of erythromycin for the Gram-positive species studied, with the exception of the oral streptococci which were equally susceptible (MIC50 0.03 mg/l) to both macrolides. Activity similar to that of erythromycin was observed against Str. pneumoniae (MIC values 0.015-0.12 mg/l), Staph. aureus (MIC 0.12-1 mg/l) and beta-haemolytic streptococci (MIC 0.06-4 mg/l). Incubation in a CO2 enriched atmosphere decreased activity of both erythromycin and CP-62,993. The effect was more marked for CP-62,993, the MIC50s of all groups of organisms being increased four-fold when they were incubated in the presence of 5 or 10% CO2.
Dunkin
K T
KT
Department of Medical Microbiology, Bangor District General Hospital, Gwynedd, UK.
Jones
S
S
Howard
A J
AJ
D017963:Azithromycin; D004305:Dose-Response Relationship, Drug; D004917:Erythromycin / Q000031:analogs & derivatives* / Q000494:pharmacology; D006193:Haemophilus influenzae / Q000187:drug effects*; D001936:Moraxella catarrhalis / Q000187:drug effects*; D013210:Staphylococcus / Q000187:drug effects*; D013211:Staphylococcus aureus / Q000187:drug effects; D013291:Streptococcus / Q000187:drug effects*; D013296:Streptococcus pneumoniae / Q000187:drug effects
D004917:Erythromycin; D017963:Azithromycin