Biomedical subjects

B H Yagi

Publications and source records attributed to B H Yagi.

5 recordsLinked to original sources

PubMed1992

The bactericidal activity and postantibiotic effect of trospectomycin.

Trospectomycin sulfate (trospectomycin, TRS) is a novel, broad-spectrum, aminocyclitol antibiotic that is being developed clinically for the treatment of upper respiratory tract infections, bacterial vaginosis, pelvic inflammatory disease, and gonorrhea. This study investigated the bactericidal activity (by time-kill kinetics) and the postantibiotic effect (PAE) of TRS. Species-dependent bacteriostatic/bactericidal activity was observed for TRS; the antibiotic was bacteriostatic for Staphylococcus epidermidis, Enterococcus faecalis, and Escherichia coli, and bactericidal for Haemophilus influenzae, Neisseria gonorrhoeae, Moraxella catarrhalis, and Bacteroides fragilis (one of two test strains). When TRS was tested at four times its minimum inhibitory concentration or at a maximum test concentration of 32 micrograms/ml, with a 1-hr exposure period, the following PAE values were recorded: S. epidermidis 30032, 1.8 hr, En. faecalis ATCC 29212, 1.6 hr, E. coli UC 311, 1.5 hr, E. coli UC 9451, 1.5 hr, H. influenzae 30063, greater than 4.0 hr, B. fragilis ATCC 25285, 5.2 hr, and B. fragilis UC 12199, 6.7 hr. The broad-spectrum PAE that was observed for TRS is somewhat unique compared with other antibiotics.

Anti-Bacterial Agents↗

PubMed1991

Estimating the postantibiotic effect: a two-phase mathematical model.

The postantibiotic effect (PAE) is a suppression of bacterial growth that persists after a short exposure to antimicrobials. The active antibiotic delays the resumption of normal growth. This suppression of bacterial growth following antibiotic removal is described by a two-phase model. The quantification of PAE is a function of the model parameters, for which consistent and asymptotically normal estimators are available.

Anti-Bacterial Agents↗

PubMed1990

In vitro activity of cefpodoxime proxetil (U-76,252; CS-807) against Neisseria gonorrhoeae.

Cefpodoxime proxetil is an oral cephalosporin antibiotic. The in vitro activities of cefpodoxime (the active metabolite of cefpodoxime proxetil), ceftriaxone, and cefuroxime against both antibiotic-susceptible and antibiotic-resistant clinical isolates of Neisseria gonorrhoeae were determined. Cefpodoxime inhibited all penicillin-susceptible strains and penicillinase-producing strains at less than or equal to 0.015 microgram/ml; chromosomally resistant strains were inhibited by cefpodoxime at less than or equal to 0.125 microgram/ml.

Ceftizoxime↗

PubMed1990

In vitro antibacterial activity and interactions with beta-lactamases and penicillin-binding proteins of the new monocarbam antibiotic U-78608.

U-78608, a new monocarbam antibiotic, was evaluated for in vitro activity against 312 clinical isolates of aerobic and anaerobic bacteria and subjected to several in vitro biochemical tests characterizing its interactions with beta-lactamases and penicillin-binding proteins (PBPs). The antibacterial activity of the compound was compared directly with those of SQ 83,360 (pirazmonam) and aztreonam. U-78608, SQ 83,360, and aztreonam had generally poor activity against gram-positive aerobic bacteria and anaerobic bacteria. U-78608 demonstrated activity primarily against gram-negative aerobic bacteria, with potency generally comparable to that of SQ 83,360. U-78608 and SQ 83,360 were less active than aztreonam for some gram-negative species; however, both compounds were 8- to 64-fold more active than aztreonam against Acinetobacter species, Pseudomonas aeruginosa, and Pseudomonas maltophilia. All three compounds resisted inactivation by several different beta-lactamases from gram-positive and gram-negative bacteria. Neither U-78608 nor SQ 83,360 exhibited significant inhibition of these enzymes, while aztreonam inhibited beta-lactamases from P. aeurginosa and Klebsiella oxytoca. All three compounds exhibited strong affinity to PBP 3 of Escherichia coli and moderate to negligible affinity to the other E. coli PBPs; quantitative measurements indicated that U-78608 had greater PBP 3 affinity than either SQ 83,360 or aztreonam.

Anti-Bacterial Agents↗

PubMed1988

In vitro antibacterial activity of trospectomycin (U-63366F), a novel spectinomycin analog.

Trospectomycin (U-63366F) is a novel spectinomycin analog with broad-spectrum antibacterial activity. The in vitro activity of this analog was compared with that of spectinomycin and other reference antibiotics against 411 clinical isolates of aerobic and anaerobic bacteria. MICs were determined by agar or broth dilution methods. The stability of trospectomycin in the presence of an enzyme extract derived from spectinomycin-resistant Escherichia coli was determined. Trospectomycin was more active than spectinomycin (4- to 32-fold) against strains of numerous bacterial species, including staphylococci, streptococci, Haemophilus influenzae, Branhamella catarrhalis, Neisseria gonorrhoeae, Proteus species, Bacteroides species, Clostridium difficile, Clostridium species, and Chlamydia trachomatis. Trospectomycin demonstrated a moderate level of activity (comparable to that of spectinomycin) for most species of the family Enterobacteriaceae tested and was generally cross resistant with spectinomycin. Trospectomycin was susceptible to inactivation by crude enzyme preparations from spectinomycin-inactivating strains of E. coli. Trospectomycin inhibited a variety of clinically important organisms, including agents of sexually transmitted diseases and pelvic inflammatory disease. Clinical studies with this novel aminocyclitol antibiotic are in progress.

Anti-Bacterial Agents↗