Kaori Bandoh

Biochemical properties and purification of metallo-beta-lactamase from Bacteroides fragilis.

The beta-lactamase from Bacteroides fragilis GAI-30144 hydrolyzed imipenem, oxyiminocephalosporins, cephamycins, and penicillins. Enzyme activity was inhibited by EDTA. Zinc completely reversed inactivation of the enzyme by EDTA. The molecular mass of purified enzyme was estimated to be 33,000 daltons. Images

Macrolide accumulation by Bacteroides fragilis ATCC 25285.

The accumulation of macrolide antibiotics in Bacteroides fragilis ATCC 25285 was increased in the order erythromycin, josamycin, and rokitamycin, depending on hydrophobicity. The half-times of efflux were also prolonged in the same order. Furthermore, MICs of the antibiotics were correlated with the extent of hydrophobicity. These findings suggest that the macrolide antibiotics are accumulated in B. fragilis by means of their hydrophobic properties, and the efficient accumulation of the drugs may explain the susceptibility of this gram-negative bacterium to macrolides.

In vitro susceptibility of clinical isolates ofBacteroides fragilis andBacteroides thetaiotaomicron in Japan

A nationwide survey of the susceptibility of 433 isolates ofBacteroides fragilis and 149 isolates ofBacteroides thetaiotaomicron was conducted from December 1986 through November 1989 in Japan. These strains were collected from 16 university hospitals and one metropolitan hospital. Metronidazole was the most active drug against both species, with no resistant isolates found. The activity of imipenem and sulbactam-cefoperazone was good, with very low resistance rates determined inBacteroides fragilis (1.4 % and 1.6 %, respectively) and inBacteroides thetaiotaomicron (3.4 % for both drugs), and was comparable to that of metronidazole. Cefoxitin, cefmetazole, cefotetan, cefbuperazone, latamoxef and ceftizoxime were found to be more active againstBacteroides fragilis, for which resistance rates were 3.2 to 9.5 %, than againstBacteroides thetaiotaomicron, for which resistance rates were 18.1 to 21.8 %. Rates of piperacillin resistance in the two species were 12.9 % and 26.8 %, respectively. Clindamycin was very active at a low concentration (MIC50 of 0.39 to 1.56 mg/l), but 24 % and 27.5 % ofBacteroides fragilis andBacteroides thetaiotaomicron isolates, respectively, were resistant to this agent.

Comparative In Vitro Activity of AM-1155, a New Quinolone, against Anaerobic Bacteria

AM-1155 is a new fluoroquinolone; its chemical structure is shown in figure 1. The molecular weight of this compound is 402.42g. Although many studies have investigated the activity of new quinolones against aerobic bacteria (Fuchs et al. 1991; Neu et al. 1992), few have examined their activity against anaerobic bacteria. We evaluated the in vitro activity of AM-1155 against obligate anaerobic bacteria and a fastidious facultative anaerobe, Gardnerella vaginalis (Gibbs et al. 1987). We also compared its activity with those offive other fluoroquinolones and cefmetazole.

Inhibition of bacterial regrowth in the puerperal uterine cavity of flomoxef

Abstract The inhibition of bacterial regrowth by flomoxef (FMOX), a beta lactam, was determined using bacteria identified in the puerperal uterine cavity. FMOX was administered to five women within the first postpartum day, and the effective regrowth time (ERT), the time required to return to pretreatment bacterial count, was measured. Among aerobic gram-positive cocci, ERT values were 10, 12, and 16 hours for Staphylococcus aureus, Staphylococcus epidermidis , and Streptococcus agalactiae , respectively. Among aerobic gram-negative bacilli, the ERT was 24 hours for Escherichia coli and 6 hours for Burkholideria cepacia . Among anaerobic gram-positive bacteria, the ERT was 12 hours for both Peptostreptococcus anaerobius and Peptostreptococcus micros . Among anaerobic gram-negative bacteria, the ERT was 12 hours for Bacteroides fragilis and 7 hours for Prevotella bivia . ERT values obtained in this study may be useful indicators for the effectiveness of chemotherapeutic agents and dosage regimens in the treatment of infectious diseases in obstetrics and gynecology. The puerperal uterine cavity may be a good in vivo site for testing of various antimicrobial therapies.