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Biomedical subjects

K P Fu

Publications and source records attributed to K P Fu.

At least 19 recordsLinked to original sources
PubMed1992

In vitro activity of l-ofloxacin against norfloxacin-resistant coagulase-negative staphylococci.

The in vitro activity of l-ofloxacin was determined against coagulase-negative staphylococci that were induced to norfloxacin resistance. l-Ofloxacin was the most active agent tested with an MIC90 of 4 micrograms/ml compared with greater than 128, 32, and 128 micrograms/ml for norfloxacin, ciprofloxacin, and enoxacin, respectively. Rifampin-resistant, coagulase-negative staphylococci were not cross-resistant to the quinolones tested. Among the rifampin-resistant organisms tested, l-ofloxacin was also the most active agent with an MIC90 of 0.25 micrograms/ml.

Anti-Bacterial Agents↗
PubMed1992

In vitro and in vivo antibacterial activities of levofloxacin (l-ofloxacin), an optically active ofloxacin.

The antibacterial activity of levofloxacin was compared with those of ofloxacin, ciprofloxacin, and other antibiotics. In general, levofloxacin was equally active or up to fourfold more active than ofloxacin against all 801 organisms tested. Levofloxacin was twofold [corrected] more active than ciprofloxacin against Streptococcus pneumoniae and 2- to 4-fold more active than ciprofloxacin against Staphylococcus aureus, Xanthomonas maltophilia, and Bacteroides fragilis. Levofloxacin was two- to eightfold more active than ciprofloxacin against coagulase-negative staphylococci and Acinetobacter spp., although these improvements in potency may not be clinically relevant. Levofloxacin inhibited 90% of streptococci when it was used at concentrations of 1 to 2 micrograms/ml. Levofloxacin was two- to fourfold less active than ciprofloxacin against most members of the family Enterobacteriaceae, such as Escherichia coli; Klebsiella pneumoniae; Citrobacter, Proteus, Providencia, Salmonella, and Yersinia spp.; and Pseudomonas aeruginosa. Both compounds were equally active against Pseudomonas cepacia. The in vitro DNA gyrase inhibitory activity of levofloxacin was as potent as that of ciprofloxacin, with a 50% inhibitory concentration of 0.65 micrograms/ml against an E. coli enzyme. In vivo, oral treatment with levofloxacin was as efficacious or more efficacious than that with ciprofloxacin in systemic as well as pyelonephritis infections in mice. Levofloxacin achieved higher concentrations in the serum and tissue of mice than did ciprofloxacin. This study presents some potential advantages of the pure L isomer of ofloxacin over ciprofloxacin and other quinolones.

Animals↗
PubMed1992

Saperconazole: in vitro and in vivo anticandidal activity.

The in vitro activity of saperconazole against eight candidal species (81 strains) was determined and compared with fluconazole, Sch 39304 and amphotericin B. Using brain heart infusion broth with an inoculum of 10(4) CFU/ml, the MIC ranges (micrograms/ml) of saperconazole were: less than or equal to 0.015- greater than 32 for Candida albicans, less than or equal to 0.015-16 for C. tropicalis, less than or equal to 0.015-32 for C. glabrata, less than or equal to 0.015-32 for C. parapsilosis, less than or equal to 0.015-0.12 for C. guilliermondii and less than or equal to 0.015-0.06 for C. krusei. Saperconazole was the most active agent tested against Candida species. Saperconazole and 5-fluorocytosine combinations showed synergistic interactions against Candida species, and no antagonistic interaction was demonstrated. In a rat vaginal candidiasis infection model, saperconazole and fluconazole were equipotent producing 75-100% cures at levels of 0.016-0.25%, respectively, when dosed intravaginally. After single oral dosing, saperconazole was 5-fold more potent than fluconazole with an ED50 value of 0.53 mg/kg. These data demonstrate that saperconazole is effective in a rat vaginal candidiasis infection either with a single oral dose or by intravaginal treatment.

Amphotericin B↗
PubMed1992

In vitro and in vivo antidermatophytic activity of saperconazole, a new fluorinated triazole.

The in vitro activity of saperconazole against selected isolates of dermatophytes and its in vivo efficacy in a guinea pig dermatophytic infection model using Trichophyton mentagrophytes were evaluated. Susceptibility testing was determined with an agar dilution method in three media: yeast nitrogen base agar (YNBA), brain heart infusion agar (BHIA) and Sabouraud dextrose agar (SDA). An inoculum of 1 x 10(5) CFU of T. mentagrophytes spores was placed onto the surface of these agars. Incubation was at 32 degrees C for 72 h. The MIC of saperconazole against all isolates was less than 1 microgram/ml, whereas the MIC ranged from 0.1 to > 128 micrograms/ml for fluconazole. The MIC range of saperconazole against Trichophyton species was < or = 0.002 to 0.25 micrograms/ml; against Microsporum species it was < 0.001 to 0.1 microgram/ml; and against Epidemophyton species was < or = 0.002 to 0.25 micrograms/ml. These data showed that saperconazole was the most active compound tested against these selected dermatophytes. The activities of saperconazole against T. mentagrophytes, T. rubrum and M. canis were not affected by the medium. The MICs against these organisms were < or = 0.008 micrograms/ml in SDA, YNBA or BHIA. There were 2- to 4-fold decreases in activity for fluconazole at the same conditions. In vivo, topical treatment with saperconazole at concentrations of 0.125% and 0.25% resulted in 50% and 75% microbiological cure rates, respectively, in the guinea pig topically infected with T. mentagrophytes.

Animals↗
PubMed1979

Clinical evaluation of netilmicin therapy in serious infections.

Netilmicin, a new semisynthetic aminoglycoside, was evaluated in the therapy of 33 episodes of infection in 30 patients. Eighteen patients had documented bacteremia. Infection sites included pulmonary, urinary tract and soft tissue areas. A complete bacteriologic and clinical cure rate of 85 per cent was achieved. No treatment failures occurred in the bacteremic group. Although netilmicin is less effective than gentamicin in vitro against Pseudomonas, it was clinically and bacteriologically effective. Netilmicin bacteriologic cures occurred in patients whose organisms were inhibited by 6.2 microgram/ml or less of netilmicin. Despite a uniform dosing protocol, a wide range of netilmicin serum levels was obtained. Adverse effects were limited to one case of transient nephrotoxicity and one Candida urinary suprainfection. Netilmicin appears to be an effective, safe agent for the therapy of serious infections.

Adult↗
PubMed1979

Comparative inhibition beta-lactamases by novel beta-lactam compounds.

The beta-lactamase-inhibiting activity of CP-45,899, 3,3-dimethyl-7-oxo-4-thia-1-azabicylo(3,2,0)heptane-2-carboxylic acid, 4,4-dioxide [2S-(2alpha,5alpha)], was investigated and compared with the beta-lactamase-inhibiting activity of clavulanic acid and dicloxacillin. CP-45,899 was an effective inhibitor of Staphylococcus aureus beta-lactamase and of those beta-lactamases of gram-negative bacteria which are primarily active against penicillins or equally active against penicillins and cephalosporins. The reaction of CP-45,899 with beta-lactamases was a concentration- and time-dependent event. CP-45,899 acted as a competitive inhibitor of plasmid-mediated S. aureus, Escherichia coli, and Shigella sonnei beta-lactamases and inducible Klebsiella beta-lactamase. CP-45,899 was a poor inhibitor of inducible or constitutive chromosomally mediated beta-lactamases of indole-positive Proteus, Citrobacter, and Enterobacter. CP-45,899 had lower kinetic constants for inhibition of hydrolysis than did clavulanic acid against many of the beta-lactamases which both inhibited.

Ampicillin↗
PubMed1979

Cefatrizine activity compared with that of other cephalosporins.

Cefatrizine, a new orally administered cephalosporin, was tested against 400 clinical isolates. Cefatrizine had excellent activity against gram-positive cocci, inhibiting all except enterococci at minimal inhibitory concentrations below 1 mug/ml. Cefatrizine inhibited the majority of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Salmonella at concentrations below 12.5 mug/ml. Although cefatrizine was not hydrolyzed by many beta-lactamases, it did not inhibit a number of strains of Enterobacter, Serratia, or indole-positive Proteus. Cefatrizine was more active than cephalothin or cephalexin against E. coli, Klebsiella, Enterobacter, Citrobacter, Salmonella, and Shigella. Its overall activity was less than that of cefoxitin against strains resistant to cephalothin, but its activity against cephalothin-susceptible strains was equivalent to that of cefamandole.

Bacteria↗
PubMed1979

HR 756, a new cephalosporin active against gram-positive and gram-negative aerobic and anaerobic bacteria.

The in vitro activity of HR 756, 7-[2-(2-amino-4-thiazolyl)-2-(Z)-(methoximino)acetamido] cephalosporanic acid, was investigated against 659 isolates. HR 756 inhibited Neisseria and Haemophilus species at concentrations similar to those needed with ampicillin. It inhibited beta-lactamase-producing N. gonorrhoeae and H. influenzae. HR 756 was the most active compound tested against members of the Enterobacteriaceae, inhibiting most isolates of Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Salmonella, Enterobacter, and Shigella at concentrations of less than 0.1 mug/ml. It was twice as active as carbenicillin against Pseudomonas aeruginosa and inhibited Bacteroides fragilis as well as cefoxitin. HR 756 killed E. coli, Staphylococcus aureus, and P. aeruginosa at rates similar to other beta-lactam antibiotics.

Aerobiosis↗
PubMed1979

In vitro antibacterial activity and beta-lactamase stability of SCE-129, a new cephalosporin.

SCE-129 [3-4-carbamoyl-1-pyridiniomethyl-7beta- (d-alpha-sulfophenylacetamido)-ceph-3-em-4-carboxylate] is a cephalosporin that inhibits Pseudomonas aeruginosa and Staphylococcus aureus. SCE-129 is tenfold more active than carbenicillin in inhibiting P. aeruginosa. SCE-129 has poor activity against Enterobacteriaceae compared with other cephalosporins and is 16-fold less active than the cephalosporins against streptococci. The activity of SCE-129 does not correlate with beta-lactamase stability, although SCE-129 is resistant to hydrolysis by gram-positive and gram-negative bacteria. The compound does not inhibit the hydrolysis of other cephalosporins. Although SCE-129 acts synergistically with gentamicin to inhibit some Pseudomonas, this cannot be predicted based on knowledge of resistance to one or more compounds.

Bacteria↗
PubMed1979

Antibacterial activity of a new 1-oxa cephalosporin compared with that of other beta-lactam compounds.

The in vitro activity of (6R,7R)-7-{[carboxy(4-hydroxyphenyl)acetyl]amino}-7-methoxy-3-[[(1-methyl -1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-oxa-1-azabicyclo-[4.2.0]oct-2-ene -2-carboxylic acid was tested against isolates of gram-positive and negative bacteria and compared with those of cephalothin, cefuroxime, cefamandole, cefoxitin, cefotaxime, and carbenicillin. The compound was less active than the other compounds when tested against Staphylococcus aureus and Staphylococcus epidermidis. It had equal or slightly less activity than did cefotaxime when tested against members of the Enterobacteriaceae, but was 8- to 32-fold more active than the other cephalosporins against the Enterobacteriaceae, inhibiting most isolates at concentrations less than 0.5 mug/ml. The compound was twofold more active than cefotaxime and cefoxitin against Bacteroides, and it was twofold more active than cefotaxime and fourfold more active than carbenicillin against Pseudomonas aeruginosa. In vitro activity did not correlate with either the presence or type of beta-lactamase in either Enterobacteriaceae or Pseudomonas. The compound showed minimal synergy when combined with aminoglycosides or carbenicillin.

Bacteria↗
PubMed1979

Comparative activity and beta-lactamase stability of cefoperazone, a piperazine cephalosporin.

The in vitro activity and beta-lactamase stability of 7-[d(-)-alpha-(4-ethyl-2,3-dioxopiperazino-carbonylamino) -p-hydroxyphenylacetamido]-3-[(1-methyl)-5-tetrazolylthiomethyl] -Delta(3)-cephem-4-carboxylic acid (cefoperazone), a cephalosporin analog of piperacillin, were compared with the activities and stabilities of other cephalosporins and cephamycins. The compound was less active than cephalothin or cefamandole in inhibiting Staphylococcus aureus; it was as active as cefamandole and cefoxitin against most of the Enterobacteriaceae but less active than cefotaxime. It was more active than carbenicillin or piperacillin against Pseudomonas aeruginosa. In general, the compound was not active against Bacteroides. It was hydrolyzed by the beta-lactamases of some Escherichia coli which hydrolyzed cefamandole, but was stable to most plasmid-mediated, chromosomally mediated, inducible beta-lactamases in the Enterobacteriaceae and Pseudomonas.

Bacteria↗
PubMed1979

Diffusion disk susceptibility testing with cefotaxime.

The diffusion disk susceptibility of Staphylococcus aureus, Enterobacteriaceae, and Pseudomonas aeruginosa to cefotaxime was determined. A 30-mug disk provided data for the susceptibility of P. aeruginosa, but yielded extremely large zones of inhibition against Enterobacteriaceae. A 5-mug disk seemed to provide the most useful susceptibility data for S. aureus and Enterobacteriaceae.

Cephalosporins↗
PubMed1979

Inactivation of beta-lactam antibiotics by Legionella pneumophila.

Beta-lactam-inactivating activity has been found in all sero-groups of Legionella pneumophila. The beta-lactamase activity could be detected in intact cells and released by ethylenediaminetetraacetic acid treatment, indicating that it is located in the periplasmic space. The enzyme acted primarily as a cephalosporinase hydrolyzing cefamandole, cephalothin, cephaloridine, and also penicillin G and ampicillin. Cefoxitin and cefuroxime were not hydrolyzed. Clavulanic acid and CP-45,899, beta-lactamase inhibitors, prevented the hydrolysis of cephalosporins and penicillins. The beta-lactamase activity appears to be different from that found in Enterobacteriaceae and Pseudomonas.

Anti-Bacterial Agents↗
PubMed1979

Pharmacokinetics of cefotaxime.

The pharmacokinetics of cefotaxime after intramuscular injection and intravenous infusion were determined. The mean peak serum level after the 500-mg intramuscular dose was 11.7 micrograms/ml, and it was 20.5 micrograms/ml after a 1,000-mg dose. The serum half-life was 1.2 and 1.3 h, respectively for the two doses. The apparent fractional volumes of distribution of 32 and 37 liters were not significantly different for the two doses, and the fractional serum clearance was approximately 315 ml/min per 1.73 m2 for both doses. The mean peak serum level after 1,000 mg administered by intravenous infusion over 30 min was 41.1 micrograms/ml. The half-life was 1.13 h, apparent volume of distribution was 33 liters, serum clearance 341 ml/min per 1.73 m2, and renal clearance was 130 ml/min per 1.73 m2. The pharmacology of cefotaxime is similar to the pharmacology of other cephalosporin antibiotics, but the low inhibitory levels which it has against gram-positive and gram-negative bacteria suggest that lower dosage regimens should be possible.

Adult↗
PubMed1979

The comparative beta-lactamase resistance and inhibitory activity of 1-oxa cephalosporin, cefoxitin and cefotaxime.

The beta-lactamase stability and inhibitory activity of 1-oxa cephalosporin, (6R,7R)-7-[[carboxy(4-hydroxyphenyl)acetyl]amino]-7-methoxy-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, was investigated and compared to that of cefoxitin and cefotaxime. There was no detectable beta-lactamase hydrolysis of 1-oxa cephalosporin, cefotaxime and cefoxitin when incubated with beta-lactamases of plasmid or chromosomal origin which were primarily cephalosporinases or enzymes which hydrolyzed both penicillins and cephalosporins. The beta-lactamase inhibitory activity of 1-oxa cephalosporin was comparable to that of cefoxitin and cefotaxime. At equal molar concentration of substrate and inhibitor, cefoxitin, cefotaxime and 1-oxa cephalosporin effectively inhibited cephalosporinase hydrolysis of cephaloridine. Cefoxitin and cefotaxime were more effective inhibitors than the 1-oxa cephalosporin against a Providencia enzyme, whereas cefotaxime and 1-oxa cephalosporin were more effective inhibitors of a Citrobacter cephalosporinase.

Bacteria↗
PubMed1978

Kinetics of netilmicin and gentamicin.

The kinetic parameters of netilmicin were studied in normal human subjects. In the intravenous study a steady-state was obtained in 4 subjects by the constant infusion of 2 mg/kg of netilmicin during the first hour followed by 0.5 mg/kg/hr for each of three successive hours. Creatinine clearance was greater than the simultaneous serum and renal clearance of netilmicin. In the intramuscular study 6 subjects received a single injection of 1 mg/kg of netilmicin followed by the same dose of gentamicin 1 wk later. A mean peak serum levels of 3.9 microgram/ml was found for both antibiotics, but the mean serum half-life of netilmicin was shorter than that of gentamicin. Doubling the intramuscular dose of netilmicin approximately doubled the peak serum level. In both studies 75% to 90% of the netilmicin was recovered in the urine within the first 24 hr. Netilmicin appears to be primarily excreted by glomerular filtration. The apparent volume of distribution was similar to that reported for other related aminoglycosides. Netilmicin and gentamicin have similar kinetic parameters. There were wide individual differences among normal subjects with both drugs.

Female↗