Comparative in vitro activities of cefpiramide and apalcillin against anaerobic bacteria

Abstract

The in vitro activities of two new antimicrobial agents, apalcillin and cefpiramide (SM-1652), were evaluated against 324 strains of anaerobic bacteria. Apalcillin (a penicillin derivative) and cefpiramide (a semisynthetic cephalosporin) were compared with piperacillin, moxalactam, and cefoxitin. Organisms studied included the Bacteroides fragilis group, other Bacteroides species, fusobacteria, clostridia, nonsporeforming gram-positive rods, and anaerobic cocci. Piperacillin was found to be the most active overall, inhibiting 96% of the strains tested at its achievable level in serum (128 p.g/ml). Apalcillin was comparable in activity to piperacillin, inhibiting 93% of anaerobes tested at this concentration. The other antibiotics inhibited ca. 80% of the strains at 32 pLg/ml. In terms of activities against particular species, apalcillin was active against 75% of B. fragilis group strains and 97 to 100%o of all other anaerobes. Cefpiramide inhibited 37% of B. fragilis group strains at 32 Lg/ml and 68% at 64 pg/ml (a level that may be achievable with this drug). Cefpiramide inhibited 92% of all other anaerobes at 32 ,ug/ml and 95% at 64 ,g/ml. The clostridia other than Clostridium perfringens were the most resistant (84% inhibited at 32 ,ug/ml and 95% inhibited at 64 ,ug/ml).Many new beta-lactam antibiotics have been introduced in the last several years, many of which have limited activity against anaerobic bacteria (2, 3, 10, 13). Apalcillin is a naphthyridine derivative of ampicillin which has been reported to have levels of activity comparable to those of other broad-spectrum penicillin derivatives (e.g., azlocillin, mezlocillin, and piperacillin) against a wide range of organisms and particularly good activity against Pseudomonas aeruginosa (12). Cefpiramide (SM-1652) is a semisynthetic cephalosporin whose structure, antibacterial activity, and stability to P-lactamases have been described previously (4). Cefpiramide has been reported to have excellent activity against P. aeruginosa (4, 7, 9). The purpose of this study was to investigate the activities of these two new antimicrobial agents against a wide range of anaerobic bacteria, with particular attention to the Bacteroides fragilis group, which exhibits resistance to many of the newly developed antimicrobial agents. (Table 2). Apalcillin was moderately active against some of the B. fragilis group (MIC50 = 32 ,ug/ml), but 12 of the 37 strains of B. fragilis were resistant even at 256 ,ug/ml. Thus, 25% (18 of 74) of B. fragilis group strains were resistant to the highest concentration of antibiotic tested. Others (12) have also reported similar results. Other Bacteroides species were more susceptible to apalcillin; only 2 of 75 strains were resistant at 256 ,ugIml. B. oralis, B. bivius, B. capillosus, and B. melaninogenicus subsp. melaninogenicus were more resistant than the other non-B. fragilis group Bacteroides strains tested. All of the other anaerobes tested were susceptible to apalcillin at a concentration of 64 pug/ml or less. MATERIALS AND METHODSCe...

Cell-wall-defective variants of Fusobacterium

“…The activity of antimicrobial agents against Fusobacterium species has been reported as variable in the literature (8,13,14,17,18). The inconsistency encountered between some reports primarily involves strains of F. varium and F. mortiferum.…”

Antimicrobial activities of BMY-28142, cefbuperazone, and cefpiramide compared with those of other cephalosporins

“…These antimicrobial agents possess increased resistance to hydrolysis by bacteria-mediated P-lactamases (10,14), excellent activity against aerobic and facultative anaerobic gramnegative bacteria (10,11,16) 576, 1983). Information on their in vitro spectra of activity, however, is limited (3,8,9,20,21). In this report we compared the in vitro antibacterial activity of these cephalosporins with those of cefmenoxime, cefoperazone, cefotaxime, ceftizoxime, and moxalactam against fresh nosocomial isolates.…”

“…Several 576,1983). Information on their in vitro spectra of activity, however, is limited (3,8,9,20,21). In this report we compared the in vitro antibacterial activity of these cephalosporins with those of cefmenoxime, cefoperazone, cefotaxime, ceftizoxime, and moxalactam against fresh nosocomial isolates.…”

Interpretive standards and quality control guidelines for cefpiramide disk susceptibility tests

“…Cefpiramide is a new cephalosporin with a broad spectrum of antibacterial activity, including against Pseudomonas spp., and with favorable pharmacokinetic properties (1,3,4,7,8). In this report we propose tentative zone size breakpoints for the interpretation of disk susceptibility tests.…”