In vitro activity of new beta-lactam antibiotics and other antimicrobial drugs against anaerobic isolates from obstetric and gynecological infections

Abstract

The in vitro activities of N-formimidoyl thienamycin, clindamycin, chloramphenicol, metronidazole, cefoperazone, cefotaxime, cefoxitin, moxalactam, penicillin G, and piperacillin were determined against 158 anaerobic bacteria isolated from endometrial wash cultures of women with pelvic infections. In general, Nformimidoyl thienamycin was the most active, with all organisms inhibited by cO.5 jig/ml. Chloramphenicol, clindamycin, and metronidazole inhibited all organisms by c8 ,ug/ml. The penicillins and cephalosporins exhibited variable activity of lesser degrees.Infections of the female genital tract are often of mixed aerobic/anaerobic bacterial etiology (2-4, 11). Thus, it is frequently necessary to use a combination of antibiotics to inhibit the variety of bacteria present, although treatment with a single antibiotic would be preferable. The fact that many of the new antibiotics are effective against a wider range of bacteria than most of the currently used antibiotics suggests that one or more of these may be useful in a single-agent regimen. However, although many in vitro studies have shown that these antibiotics inhibit the aerobic organisms common to obstetric and gynecological infections (1,(12)(13)(14), there are few and only limited studies (6, 7, 9) of the effectiveness of these antibiotics against species of anaerobic bacteria, such as Bacteroides bivius and anaerobic gram-positive cocci, commonly isolated from pelvic infections (3,4 no. 107, 1981).In an effort to expand on the above experience, we determined the minimal inhibitory concentrations (MICs) of cefoperazone, cefotaxime, cefoxitin, chloramphenicol, clindamycin, N-formimidoyl thienamycin, metronidazole, moxalactam, penicillin G, and piperacillin for 158 anaerobic bacteria isolated from endometrial wash cultures of 56 women admitted to San Francisco General Hospital with untreated pelvic infections (mostly salpingitis and endometritis). The organisms, identified through the use of gas-liquid chromatography and prereduced anaerobically sterilized media (5)

Recovery of anaerobic bacteria from clinical specimens in 12 years at two military hospitals

“…Knowledge of this distribution allows a logical choice of antimicrobial agents adequate for the therapy of infections in these sites. Following the recent description of B. disiens and B. bivius, they were recognized as important bacteroides isolated in OBG infections (15,20). AGPC were the second most frequently recovered anaerobes and accounted for 26% of anaerobic isolates, a finding similar to reports in previous studies (2, 14, 17, 18, 22).…”

“…Bacteroides are important anaerobic pathogens that can be recovered from a variety of infections (7,14). Members of the B. fragilis group are primarily isolated from abdominal infections (5), pigmenting Bacteroides group members are isolated from oral and respiratory tract infections (6), and B. disiens and B. bivius are isolated from female genital tract infections (15,20).…”

Role of Bacteroides bivius beta-lactamase in beta-lactam susceptibility

“…Overall, the susceptibility pattern of our isolates were similar to that reported by other groups (1,10,11,18,21). In this study the most active agent in vitro was ceftizoxime, followed by a 2:1 combination of amoxicillin and clavulanic acid.…”

Antimicrobial susceptibilities of anaerobic bacteria isolated from female genital tract infections

“…Penicillin G, on the other hand, demonstrated relatively poor activity overall against genital strains of Bacteroides spp., not only just the B. fragilis group, expressing substantial activity only against fusobacteria and gram-positive species. Similar results for some of the same species and antimicrobial agents which were obtained from endometrial wash specimens have been reported (16).…”

“…Of a total of 22 strains of P. anaerobius, the MIC of moxalactam was .8 ,ug/ml for nine strains, whereas the other strains had moxalactam MIC values of <2 ,ugIml. Three strains for which the MIC of moxalactam was -64 ,ug/ml were, in addition, considerably less susceptible than the other strains to cefotaxime (MICs, 4 ,ug/ml) and to cefoperazone, cefoxitin, and penicillin G (MICs, 8 to 16 ,ug/ml or U/ml). A similar VOL.…”