Ceftazidime: in-vitro antibacterial activity and susceptibility to  -lactamases compared with that of cefotaxime, moxalactam and other  -lactam antibiotics

Abstract

The in-vitro antibacterial activity of ceftazidime was assessed against recent clinical isolates of common bacteria and also against reference strains that produced known beta-lactamases. The compound was active, though less so than cephaloridine against staphylococci and streptococci with MICs mostly 0.12-2 mg/l for streptococci and 8 mg/l for staphylococci, but enterococci (MICs > or =64 mg/l) and methicillin-resistant staphylococci (MICs 16-32 mg/l) were resistant. Penicillin-resistant pneumococci (MICs 2-4 mg/l) were much less sensitive than other pneumococci (MICs 0.12-0.25 mg/l). Ceftazidime was also active, but slightly less so than cefotaxime or moxalactam, against enterobacteria (MICs mostly 0.12-0.25 mg/l). Its activity was also inferior to that of cefotaxime against Neisseria gonorrhoeae (MICs mostly 0.03-0.06 mg/l) and Haemophilus influenzae (MICs mostly 0.06-0.25 mg/l). However it was about eightfold more active than cefotaxime or moxalactam against Pseudomonas aeruginosa (MICs mostly 1-4 mg/l), and it was also more active than these compounds against other pseudomonads. Ceftazidime was less active than cefoxitin against Bacteroides spp. (MICs mostly 16-64 mg/l for Bact. fragilis and 2-8 mg/l for other bacteroides) and less active than ampicillin or cefoxitin against other anaerobes. The compound was highly resistant to hydrolysis by most beta-lactamases including OXA-1 and the enzymes from Klebsiella 1082E and Proteus vulgaris PC37 which hydrolyse cefuroxime and cefotaxime. However, it was hydrolysed slowly by the enzyme from a highly ampicillin-resistant isolate of Bact. fragilis.

Randomized comparison of ceftazidime versus clindamycin-tobramycin in the treatment of obstetrical and gynecological infections

“…Aerobic gram-positive organisms are also highly susceptible to this drug. Activity against the anaerobic spectrum, especially the Bacteroides spp., is intermediate (1,10,11), but there is little existing information on the susceptibility pattern of B. bivius, a common genital pathogen. Besides its broad spectrum of activity, CAZ has a long half-life for a cephalosporin (1.8 h) and low protein binding (10o), properties which may be advantageous in the treatment of polymicrobial infections (8,9).…”

The morphological response of Pseudomonas aeruginosa to azthreonam, cefoperazone, ceftazidime and N-formimidoyl thienamycin

“…The antibiotics were azthreonam, a monocyclic Plactam (Livermore and Williams, 198 1 ;Jacobus, Ferreira and Barza, 1982). N-formimidoyl thienamycin, a p lactam that does not have a sulphur atom in the thiazolidine ring (Wise,Andrews and Patel,198 1) and two cephalosporins, cefoperazone (Kayser,Huf and Homberger,198 1) and ceftazidime (Phillips et al, 1981). To elucidate further the action of these antibiotics on P. ueruginosa, the morphological effects were studied by transmission electron microscopy.…”

Ceftazidime as single-agent therapy for gram-negative aerobic bacillary osteomyelitis

“…Ceftazidime is a new broad-spectrum cephalosporin with excellent in vitro activity against most gram-negative aerobic bacilli, including P. aeruginosa, Enterobacter species, and indole-positive Proteus species (16,17,23). Ceftazidime distributes throughout the extracellular fluid space (1,15,22,24) and thus penetrates in high concentrations into the fluids bathing the site of bone infection (25).…”