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Biomedical subjects

P C Fuchs

Publications and source records attributed to P C Fuchs.

At least 55 records · Page 3Linked to original sources
PubMed1998

In vitro activities of clinafloxacin against contemporary clinical bacterial isolates from 10 North American centers.

Clinafloxacin was more active than ciprofloxacin against 4,213 aerobic and facultative anaerobic bacterial isolates from 10 medical centers, as tested by broth microdilution and disk diffusion methods. The percentage of 201 anaerobes susceptible to clinafloxacin by broth microdilution was comparable to cefoxitin. Our data support the proposed disk diffusion interpretive criteria for aerobic bacteria with 5-microg clinafloxacin disks.

Anti-Infective Agents↗
PubMed1998

In vitro activities of the ketolide HMR 3647 against recent gram-positive clinical isolates and Haemophilus influenzae.

The ketolide HMR 3647 (previously RU 66647) was evaluated against 2, 563 recent clinical isolates of gram-positive pathogens and 200 Haemophilus influenzae isolates. HMR 3647 was active against macrolide-resistant streptococci, including pneumococci, but was not active against macrolide- or lincosamide-resistant staphylococci. Against H. influenzae, the potency of HMR 3647 was similar to that of azithromycin.

Anti-Bacterial Agents↗
PubMed1997

Susceptibility testing quality control studies with fosfomycin tromethamine.

Multiple studies were performed to define the quality control ranges for susceptibility tests of fosfomycin tromethamine. For disk diffusion tests, the limits proposed are 22 to 30 mm for Escherichia coli ATCC 25922 and 25 to 33 mm for Staphylococcus aureus ATCC 25923. Broth microdilution tests were not reproducible. For agar dilution tests, ranges proposed are 0.5 to 2.0 micrograms/ml for Escherichia coli ATCC 25922, 0.5 to 4.0 micrograms/ml for Staphylococcus aureus ATCC 29213; 2.0 to 8.0 micrograms/ml for Pseudomonas aeruginosa ATCC 27853, and 32 to 128 micrograms/ml for Enterococcus faecalis ATCC 29212.

Anti-Bacterial Agents↗
PubMed1997

In vitro activity of the new ketolide HMR 3004 compared to an azalide and macrolides against Streptococcus pneumoniae and Haemophilus influenzae.

The purpose of this study was to compare the in vitro activity of a new ketolide, HMR 3004 (RU64004), to that of three macrolides and one azalide against 608 Streptococcus pneumoniae and 202 Haemophilus influenzae. Macrolide-resistant pneumococci were susceptible to HMR 3004, even if they were resistant to clindamycin. Against Haemophilus influenzae, HMR 3004 and azithromycin were nearly identical in potency; the macrolides were 8- to 16-fold less active. HMR 3004 may be useful for treating respiratory tract infections if sufficient concentrations can be achieved at the local sites of infection.

Ampicillin Resistance↗
PubMed1997

In vitro activity of an orally administered streptogramin (RPR 106,972) compared to quinupristin/dalfopristin and erythromycin.

The antibacterial activities of RPR 106,972 and quinupristin/dalfopristin (RP 59,500) were determined by the broth microdilution susceptibility test method. No major differences were seen among MICs for 863 isolates representing 22 species. However, there were minor twofold differences in MICs for some species. On a weight-to-weight basis, the activities of the oral and parenteral streptogramins were essentially the same. Because the route of administration and the pharmacokinetics differ, it is not necessarily appropriate to extrapolate such in vitro observations to predict identical clinical and bacteriological response rates for the two drugs.

Anti-Bacterial Agents↗
PubMed1997

Reproducibility of broth microdilution and disk diffusion susceptibility tests of nine antimicrobial agents against Streptococcus pneumoniae ATCC 49619.

Collaborative studies documented the reproducibility of broth microdilution susceptibility tests of Streptococcus pneumoniae against nine antimicrobial agents and of disk diffusion tests with six of those drugs. Replicate tests of Streptococcus pneumoniae ATCC 49619 in five different laboratories led to the following provisional quality control limits: cefdinir--0.03 to 0.25 microgram/ml and 26 to 31 mm; cefetamet--0.5 to 2 micrograms/ml and 20 to 25 mm; ciprofloxacin--0.25 to 1 microgram/ml and 20 to 26 mm; clinafloxacin--0.03 to 0.125 microgram/ml and 28 to 34 mm; grepafloxacin--0.06 to 0.5 microgram/ml and 21 to 28 mm; PD131628--0.125 to 0.5 microgram/ml and 24 to 29 mm; clindamycin--0.03 to 0.12 microgram/ml; cefpodoxime--0.03 to 0.12 microgram/ml; and trospectomycin--1 to 4 microgram/ml (disk tests were not evaluate for the latter three drugs).

Anti-Bacterial Agents↗
PubMed1997

Provisional interpretive criteria for quinupristin/dalfopristin susceptibility tests.

For testing bacterial susceptibility to the streptogramin quinupristin/dalfopristin, it seems reasonable that the test reagent should contain a similar ratio of the two compounds as in the therapeutic material, i.e. 30% quinupristin and 70% dalfopristin. The precise ratio of quinupristin to dalfopristin is not critical as long as threshold concentrations of both drugs are present. In-vitro tests were not altered by minor changes in pH, incubation in CO2 or by addition of lysed horse blood to the medium. Filter paper discs containing 15 micrograms of the quinupristin/dalfopristin reagent are preferred for agar diffusion susceptibility testing in order to optimize disc tests with enterococci. Provisional interpretive criteria for pathogens not requiring blood or increased CO2 are: susceptible, inhibition zone diameters of > or = 19 mm or MIC < or = 1.0 mg/L; intermediate, 16-18 mm or MIC 2.0 mg/L; resistant, < or = 15 mm or MIC > or = 4.0 mg/L. Those criteria will need to be reassessed as clinical experiences become available. Of particular concern is the role of quinupristin/dalfopristin in the treatment of infections due to Haemophilus influenzae or Enterococcus faecalis: the clinically relevant interpretive category for each of those two species is yet to be determined.

Anti-Bacterial Agents↗
PubMed1997

Interpretive criteria and quality control parameters for testing of susceptibilities of Haemophilus influenzae and Streptococcus pneumoniae to trimethoprim and trimethoprim-sulfamethoxazole. The Antimicrobial Susceptibility Testing OC Group.

Two hundred twenty-eight strains of Haemophilus influenzae and 234 strains of Streptococcus pneumoniae were tested by broth microdilution and disk diffusion methods for susceptibility to trimethoprim (TMP) and TMP-sulfamethoxazole (SMX) to evaluate proposed criteria. Data are presented to support the proposed TMP MIC breakpoints of < or = 2.0 micrograms/ml for susceptibility and > or = 4.0 micrograms/ml for resistance for both species and TMP-SMX MIC breakpoints of < or = 2.0-38 micrograms/ml for susceptibility and > or = 4.0-76 micrograms/ml for resistance. Corresponding zone diameter breakpoints for H. influenzae for both drugs are proposed: < or = 10 mm = resistant; > or = 16 mm = susceptible. A 10-laboratory study documented reproducibility of such tests with standard control strains. The following control limits are proposed for tests of H. influenzae ATCC 49247 against TMP; MIC, 0.12 to 0.5 microgram/ml; zone diameter, 27 to 33 mm. The current limits for TMP-SMX were confirmed. For tests of S. pneumoniae ATCC 49619, MICs of TMP were 1.0 to 4.0 micrograms/ml and the current TMP-SMX MIC range was confirmed. Disk susceptibility tests of either drug against pneumococci were not reproducible, and consequently neither quality control limits nor interpretive criteria could be established. Endpoint interpretation and lot-to-lot variability in Mueller-Hinton agars were significant factors leading to interlaboratory variability.

Anti-Bacterial Agents↗
PubMed1997

Antibacterial activities of grepafloxacin, ciprofloxacin, ofloxacin and fleroxacin.

Grepafloxacin (OPC-17116) and three other fluoroquinolones were tested against 461 bacterial isolates representing 44 species. Grepafloxacin was superior to ciprofloxacin, ofloxacin and fleroxacin in its activity against the Gram-positive cocci, including staphylococci, pneumococci and hemolytic streptococci. Attempts to select grepafloxacin-resistant mutants from a methicillin-resistant Staphylococcus aureus strain were unsuccessful, although ciprofloxacin readily selected quinolone-resistant mutants of that strain. Among Gram-negative bacilli other than Escherichia coli, mutants were readily selected by in vitro exposure to either grepafloxacin or ciprofloxacin. All such mutants showed complete cross resistance to six other quinolones. The four study drugs were active against nalidixic acid-susceptible strains belonging to 13 species of the Enterobacteriaceae, but ciprofloxacin was the most potent drug studied. Against Acinetobacter spp. and Stenotrophomonas maltophilia, grepafloxacin was two- to four-times more active than ciprofloxacin. However, against Pseudomonas aeruginosa, ciprofloxacin was two- to four-times more potent than grepafloxacin. Grepafloxacin and ciprofloxacin were both found to be bactericidal agents.

Anti-Infective Agents↗
PubMed1997

Streptococcus pneumoniae killing rate and post-antibiotic effect of levofloxacin and ciprofloxacin.

In vitro killing rates for levofloxacin and ciprofloxacin for six strains of Streptococcus pneumoniae were determined by the time-kill method outlined by the NCCLS. Both drugs were bactericidal at concentrations of two and four times their respective minimum inhibitory concentrations (MICs). Levofloxacin achieved a 99.9% kill on average in 1 hour more rapidly than ciprofloxacin. Post-antibiotic effect was also determined for both drugs against the same six strains. A post-antibiotic effect for a mean of 1.2 and 1.0 hours was observed for levofloxacin and ciprofloxacin, respectively. The latter means were not considered significantly different.

Anti-Infective Agents↗
PubMed1996

Methods of measuring susceptibility of anaerobic bacteria to trovafloxacin, including quality control parameters.

Three methods approved by the National Committee for Clinical Laboratory Standards for testing the susceptibility of anaerobic bacteria were used to evaluate the fluoroquinolone, trovafloxacin. The methods gave essentially comparable results with 126 anaerobes and with three quality control strains. A collaborative study defined the quality control range for trovafloxacin MICs. Trovafloxacin had good in vitro activity against the more common anaerobes (MIC 90 < = or 2.0 micrograms/ml).

Anti-Infective Agents↗
PubMed1996

In vitro activity and selection of disk content for disk diffusion susceptibility tests with trovafloxacin.

The activity of the new fluoroquinolone trovafloxacin (CP-99,219) was compared with that of ciprofloxacin and ofloxacin against 517 bacterial isolates representing 50 different species. Against members of the family Enterobacteriaceae, all three drugs showed good in vitro activity. Against most anaerobic bacteria, Staphylococcus, Streptococcus, and Enterococcus species, trovafloxacin was four- to sixteenfold more active than ciprofloxacin. For disk diffusion testing, 10 micrograms trovafloxacin disks gave satisfactory results. Tentative criteria are proposed for use during clinical studies.

Anti-Infective Agents↗
PubMed1996

In vitro activity of ceftizoxime, ceftazidime, cefuroxime, ceftriaxone, cefotaxime, and penicillin against Streptococcus pneumoniae as determined by three quantitative methods.

E-test, broth microdilution, and agar dilution susceptibility tests were used to evaluate penicillin and five extended-spectrum cephalosporins against 196 strains of Streptococcus pneumoniae with different levels of penicillin resistance. Oxacillin disk tests corresponded to minimum inhibitory concentrations of penicillin determined by the E-test better than those generated by broth microdilution or agar dilution methods. Relative potency of the study drugs was as follows: cefotaxime = ceftriaxone > penicillin > cefuroxime > ceftizoxime > ceftazidime.

Cefotaxime↗