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P C Fuchs

Publications and source records attributed to P C Fuchs.

12 recordsLinked to original sources
PubMed1979

Fortimicin A: collaborative in vitro susceptibility. Comparison with amikacin and gentamicin against 11,840 clinical bacterial isolates.

The susceptibility of 11,840 clinical bacterial isolates to fortimicin A was determined by agar dilution or broth microdilution methods and compared with their susceptibility to amikacin and gentamicin. In general, the in vitro activity of fortimicin A was essentially the same as that of amikacin. Significant exceptions were the increased effectiveness of fortimicin A against Serratia marcescens and the greater activity of amikacin against Pseudomonas and other nonfermentative gram-negative bacilli. On a weight-for-weight basis, gentamicin showed greater activity than the other two antimicrobial drugs against most species; S. Marcescens was the major exception. However, at concentrations equivalent to achievable nontoxic serum levels, the proportion of isolates inhibited by the three drugs was quite comparable. There were several strains with unusually high resistance to one or more of the tested antibiotics. These usually occurred in one of the six participating institutions and could be traced to specific enzyme-producing or permeability mutants endemic to that particular institution.

Amikacin↗
PubMed1978

Reassessment of the "class" concept of disk susceptibility testing. Cephalothin disks versus minimal inhibitory concentrations with eleven cephalosporins.

Reassessment of the "class" concept of disk susceptibility testing. Cephalothin disks versus minimal inhibitory concentrations with eleven cephalosporins. Am J Clin Pathol 70: 909--913, 1978. Studies were carried out to determine whether susceptibility or resistance to 11 cephalosporins could be predicted reliably from the results of tests with a single cephalothin disk. The cephalosporins were tested with a microdilution technic and with a standardized disk test. Strains susceptible to a cephalothin disk were predictably susceptible to all other cephalosporins. However, 2--12% of the strains were resistant to cephalothin disks but were susceptible to the more active parenteral drugs cefoxitin, cephamandole, cefuroxime, and BL-S786. Because of differences in antimicrobial activities, the cephalosporins could be divided into three subgroups for purposes of susceptibility testing: one subgroup includes the majority of cephalosporins and may be represented by tests with cephalothin, the second subgroup inclues three active parenteral drugs (cephamandole, cefuroxime, and BL-S786) and may be represented by tests with cefuroxime, and the third subgroup consists of cefoxitin, a cephamycin with a unique broad spectrum of activity. Until the drugs in the second and third subgroups are released for general therapeutic use, the practice of testing only one cephalosporin disk appears to be a reasonably reliable procedure.

Bacteria↗
PubMed1978

Stability of antimicrobials in Schaedler's anaerobic and brain heart infusion broths stored at --20 degrees C.

Penicillin-like drugs are found to be unstable in SCHAEDLER'S broth in forzen storage (--20 degrees C). Chloramphenicol, clindamycin and tetracycline remained at original potency to 45 days. No detectable antimicrobial decay was found in two formulations of supplemented BHI broth. Antimicrobial potency was measured by quality control organism endpoints, bioassays and MIC changes in use at four clinical microbiology laboratories.

Anaerobiosis↗
PubMed1977

Piperacillin (T-1220), a new semisynthetic penicillin: in vitro antimicrobial activity comparison with carbenicillin, ticarcillin, ampicillin, cephalothin, cefamandole and cefoxitin.

Piperacillin (T-1220) is a new semisynthetic penicillin with an unusually broad spectrum of antimicrobial activity. In vitro comparisons of this drug with 6 other beta-lactam antimicrobics (ticarcillin, carbenicillin, ampicillin, cephalothin, cefamandole and cefoxitin) were conducted. These included minimal inhibitory concentrations (MIC) against 394 bacterial isolates, the minimal lethal concentrations (MLC) against 79 of those, as well as the effect of inoculum size on the MIC and MLC of the drugs. Piperacillin had significantly greater activity than did the other penicillins against Pseudomonas species and Klebsiella pneumoniae. Against P. aeruginosa piperacillin was 8- and 16-fold more active than ticarcillin and carbenicillin, respectively. The MLC of piperacillin rarely differed from the MIC by more than one log2 dilutions except against P. aeruginosa in which the MLC was 4-fold greater or more than the MIC of 45% of isolates tested. Ticarcillin, carbenicillin and cefoxitin showed minimal inoculum size effects. Cefamandole results showed the greatest inoculum size variation with 55% and 37% of isolates showing an 8-fold increase in MIC and MLC respectively by increasing inoculum from 10(5) to 10(7) CFU/ml. Piperacillin was intermediately effected having 25% of strains greater than 8-fold increase in MIC.

Ampicillin↗
PubMedDate not supplied

Ticarcillin: a collaborative in vitro comparison with carbenicillin against over 9,000 clinical bacterial isolates.

The minimal inhibitory concentrations of ticarcillin and carbenicillin were determined for 9,236 clinical bacterial isolates by the broth microdilution method at four participating laboratories. Ticarcillin showed significantly increased activity against Klebsiella pneumoniae (P less than .001), Pseudomonas aeruginosa (P less than .001) and Aeromonas hydrophilia (P less than .005) when compared to carbenicillin, but no signifcant differences were observed against other gram-negative organisms. Ticarcillin was consistently less active against the gram-positive cocci, and these differences were significant for Staphylococcus aureus (P less than .001), Streptococcus agalactiae (P less than .001), Staphylococcus epidermidis (P less than .001) and Streptococcus viridans (P less than .005). Significant regional and institutional differences in susceptibility to the two drugs were observed for several species, including common nosocomial pathogens such as S. aureus, P. aeruginosa, K. pneumoniae and Escherichia coli.

Bacillus↗