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Biomedical subjects

P C Fuchs

Publications and source records attributed to P C Fuchs.

At least 199 records · Page 11Linked to original sources
PubMed1984

Temocillin: in vitro activity against 734 selected clinical isolates, including beta-lactamase-producing strains.

The in vitro activity of temocillin against 734 clinical isolates was tested by broth microdilution. Good activity was demonstrated against Enterobacteriaceae and both beta-lactamase-positive and -negative strains of Haemophilus influenzae and Neisseria gonorrhoeae. There was little to no activity against gram-positive cocci and nonfermenting gram-negative bacilli. Bactericidal activity and effect of inoculum size on temocillin activity were comparable to that of ticarcillin. Temocillin was stable to commonly encountered beta-lactamases and significantly inhibited Richmond-Sykes type 1 enzymes of Enterobacter cloacae.

Bacteria↗
PubMed1984

Assessment of catheter-associated infection risk with the Hickman right atrial catheter.

One hundred fifty Hickman right atrial catheters were inserted into 143 patients and were followed prospectively until removal. Primary indications for their use were: cancer chemotherapy (45), parenteral nutrition (35), antibiotic therapy (63), and miscellaneous (7). The overall catheter-associated infection rate was 12.0%. Since the mean duration of catheterization was 125 days, the infection/duration rate was 1.0/1,000 days of use. The risk of infection differed significantly according to the primary indication for catheterization: parenteral nutrition greater than antibiotic therapy greater than cancer chemotherapy. The increased risk of catheter-associated infection attributable to duration of catheterization was additive, and the per day risk of such infections remained constant regardless of duration. Nearly two-thirds of patients were discharged home with catheters in place, without adversely affecting infection risk.

Adolescent↗
PubMed1984

In vitro activity of ticarcillin plus clavulanic acid against 632 clinical isolates.

A total of 632 clinical bacterial isolates were tested for susceptibility to twofold dilutions of ticarcillin alone and in combination with 1, 2, and 4 micrograms of clavulanic acid (CA) (Timentin) per ml by a reference microdilution method. With the addition of CA, ticarcillin MICs were reduced eightfold or greater with 54 of 59 (92%) strains of the family Enterobacteriaceae with ticarcillin MICs of greater than or equal to 64 micrograms/ml. The inhibitory effect of CA on pseudomonads was minimal. Ticarcillin MICs for beta-lactamase-producing Haemophilus influenzae, Neisseria gonorrhoeae, and most Staphylococcus aureus were reduced to less than or equal to 0.5 micrograms/ml when CA was added. For dilution susceptibility testing of ticarcillin-clavulanic acid, dilutions of ticarcillin combined with 2 micrograms of CA per ml is suggested.

Bacteria↗
PubMed1984

Disk diffusion susceptibility testing of ticarcillin plus clavulanic acid.

Disk diffusion susceptibility testing of ticarcillin plus the beta-lactamase inhibitor clavulanic acid was performed on 489 clinical isolates, and the results were compared with reference broth microdilution susceptibilities. Four different disks containing 75 micrograms of ticarcillin plus 2.5, 5, 10, and 15 micrograms of clavulanic acid were evaluated. Based on test performance and clavulanic acid stability, the 75-10-micrograms disk is recommended. Interpretive criteria for ticarcillin as published by the National Committee for Clinical Laboratory Standards appear to be satisfactory for the combination drug, but because the number of ticarcillin-clavulanic acid-resistant isolates was small, this proposal must be considered only tentative.

Bacteria↗
PubMed1984

Disk diffusion testing, quality control guidelines, and antimicrobial spectrum of HR810, a fourth-generation cephalosporin, in clinical microbiology laboratories.

HR810 is a new, very broad-spectrum cephalosporin with significant activity against members of the family Enterobacteriaceae, pseudomonads, gram-positive cocci, and anaerobes that is generally greater than the third-generation cephalosporins (99.6% of 4,128 clinical facultative enteric isolates were inhibited by less than or equal to 8.0 micrograms of HR810 per ml). Tests and statistical methods to establish in vitro antimicrobial susceptibility test criteria favor tentative breakpoints of greater than or equal to 18 mm (less than or equal to 8.0 micrograms/ml) as susceptible and less than or equal to 14 mm (greater than or equal to 32 micrograms/ml) as resistant. This provides a 93.7 to 98.3% absolute interpretive accuracy. Several preliminary ranges for zone sizes obtained with quality control organisms are proposed for the 30-micrograms HR810 disk diffusion test used during the clinical trials.

Bacteria↗
PubMed1983

In vitro evaluation of Augmentin by broth microdilution and disk diffusion susceptibility testing: regression analysis, tentative interpretive criteria, and quality control limits.

Augmentin (Beecham Laboratories, Bristol, Tenn.), a combination drug consisting of two parts amoxicillin to one part clavulanic acid and a potent beta-lactamase inhibitor, was evaluated in vitro in comparison with ampicillin or amoxicillin or both for its inhibitory and bactericidal activities against selected clinical isolates. Regression analysis was performed and tentative disk diffusion susceptibility breakpoints were determined. A multicenter performance study of the disk diffusion test was conducted with three quality control organisms to determine tentative quality control limits. All methicillin-susceptible staphylococci and Haemophilus influenzae isolates were susceptible to Augmentin, although the minimal inhibitory concentrations for beta-lactamase-producing strains of both groups were, on the average, fourfold higher than those for enzyme-negative strains. Among the Enterobacteriaceae, Augmentin exhibited significantly greater activity than did ampicillin against Klebsiella pneumoniae, Citrobacter diversus, Proteus vulgaris, and about one-third of the Escherichia coli strains tested. Bactericidal activity usually occurred at the minimal inhibitory concentration. There was a slight inoculum concentration effect on the Augmentin minimal inhibitory concentrations. On the basis of regression and error rate-bounded analyses, the suggested interpretive disk diffusion susceptibility breakpoints for Augmentin are: susceptible, greater than or equal to 18 mm; resistant, less than or equal to 13 mm (gram-negative bacilli); and susceptible, greater than or equal to 20 mm (staphylococci and H. influenzae). The use of a beta-lactamase-producing organism, such as E. coli Beecham 1532, is recommended for quality assurance of Augmentin susceptibility testing.

Amoxicillin↗
PubMed1982

Cefotetan, a new cephamycin: comparison of in vitro antimicrobial activity with other cephems, beta-lactamase stability, and preliminary recommendations for disk diffusion testing.

Cefotetan is a new, potent, 7 alpha-methoxy cephalosporin (cephamycin). The in vitro activity of cefotetan tested in a multiphasic, collaborative study against 12,260 consecutive clinical isolates and 448 selected isolates showed 93% of Enterobacteriaceae, 90% of methicillin-susceptible Staphylococcus aureus (broth dilution), 83% of Bacteroides fragilis, and 72% of non-enterococcal streptococci to be inhibited by less than or equal to 8 micrograms/ml. Beta-Lactamase-producing and -nonproducing Haemophilus influenzae strains were inhibited by less than or equal to 1.0 micrograms/ml. Cefotetan's inhibitory spectrum paralleled those of the newest generation of cephems and exceeded those of cefoxitin and cefamandole. No useful activity was present against Streptococcus faecalis or Pseudomonas aeruginosa. Cefotetan was bactericidal without significant inoculum effect and was highly resistant to hydrolysis by Richmond-Sykes types I, III, and IV beta-lactamases. Hydrolysis of the chromogenic cephalosporin PADAC (pyridine-2-azo-p-dimethylaniline cephalosporin) by type I beta-lactamases was markedly inhibited by concentrations of cefotetan similar to those of the potent inhibitor dicloxacillin. Analysis of agar disk diffusion for several disk potencies and broth dilution susceptibility tests by regression and error rate-bounding methods produced preliminary tentative zone standards (30-micrograms disk, using minimal inhibitory concentration breakpoints of less than or equal to 8 micrograms/ml susceptible and greater than 32 micrograms/ml resistant, or 75-micrograms disk, using minimal inhibitory concentration breakpoints of less than or equal to 16 micrograms/ml susceptible and greater than or equal to 64 micrograms/ml resistant) of greater than or equal to 18 mm susceptible, less than or equal to 14 mm resistant, and 15 to 17 mm indeterminate. Staphylococcus aureus testing with the 30-micrograms disk is not recommended.

Anti-Bacterial Agents↗
PubMed1982

Performance of yeast identification systems. An analysis of the College of American Pathologists Special Mycology Survey data.

The performance of approximately 400 participants in the CAP Special Mycology Survey in identifying 15 medically important yeasts was analyzed. With nine strains, users of the API 20C system and Uni-Yeast-Tek (UYT) systems performed comparably. With two strains (Trichosporon cutaneum and Candida guilliermondii) the UYT users performed significantly better than API users; with four strains (Cryptococcus albidus, Saccharomyces cerevisiae, and two strains of Candida tropicalis), API users significantly outperformed UYT users. Analysis of biochemical reaction patterns demonstrated, with a few exceptions, good reproducibility among laboratories with both kits. With one exception (melezitose-variable Candida albicans), the few discrepancies in biochemical reactions had little or no influence on the final identification. From this analysis, we conclude that both API and UYT perform acceptably well in routine clinical laboratories when used in conjunction with morphologic observations and, when indicated, supplemented biochemical test.

Evaluation Studies as Topic↗
PubMed1981

Mezlocillin: tentative interpretive standards for disk diffusion susceptibility testing.

The susceptibility of 447 clinical bacterial isolates to mezlocillin and carbenicillin was tested by standardized agar disk diffusion and reference broth micro-dilution methods. Tentative interpretive criteria for disk susceptibility testing by using 75 micrograms mezlocillin disks are proposed: susceptible, greater than or equal to 16 mm; indeterminate, 13 to 15 mm; and resistant, less than or equal to 12 mm. These would be applicable to both Pseudomonas species and the Enterobacteriaceae, but not to Staphylococcus aureus. For S. aureus, the breakpoints for susceptible, greater than or equal to 29 mm, and resistant, less than or equal to 28 mm, hold for mezlocillin as well as for the other penicillinase-susceptible penicillins.

Bacteria↗
PubMed1981

Cefmenoxime (SCE-1365), a new cephalosporin: in vitro activity, comparison with other antimicrobial agents, beta-lactamase stability, and disk diffusion testing with tentative interpretive criteria.

The in vitro activity of cefmenoxime (SCE-1365) was evaluated in a multiphased collaborative investigation. Over 7,500 consecutive clinical isolates were tested in five laboratories, and greater than 90% of the following organisms were inhibited by cefmenoxime at the following concentrations: Enterobacteriaceae and non-enterococcal streptococci, </=0.125 mug/ml; Staphylococcus aureus, </=2.0 mug/ml; and nonfermenting gram-negative bacilli and Bacteroides fragilis group, </=32 mug/ml. Both beta-lactamase-producing and -nonproducing Haemophilus influenzae and Neisseria gonorrhoeae were inhibited by cefmenoxime at </=0.03 mug/ml. The spectrum of cefmenoxime was similar to that of other, newer cephalosporins, particularly cefotaxime. A pronounced inoculum effect was found with some species upon increasing inocula from 10(5) to 10(7) colony-forming units per ml, resulting in an approximate eightfold increase in minimum inhibitory concentrations. Cefmenoxime was bactericidal when tested with inocula of 10(5) colonyforming units per ml, and mean differences between the minimum inhibitory concentration and the minimum lethal concentration were less than one log(2) dilution. No significant hydrolysis of cefmenoxime by five different beta-lactamases was detectable, and cefmenoxime exhibited marked inhibition of type I beta-lactamases. Regression and error rate-bounded analyses of results of disk diffusion and reference broth microdilution susceptibility tests were performed on 421 bacterial isolates, and the following tentative zone size breakpoints are proposed: >/=22 mm, susceptible; </=14 mm, resistant; and 15 to 21 mm, moderately susceptible (indeterminate). These data and cross-resistance studies with other newer cephalosporins indicate marked similarity of in vitro activity within this group of drugs, particularly between cefmenoxime, moxalactam, and cefotaxime. Any one of these could serve as the representative for the disk diffusion testing of this group of drugs if comparable minimum inhibitory concentration breakpoints were used for each drug.

Bacteria↗
PubMed1981

Quality control limits for ampicillin, carbenicillin, mezlocillin, and piperacillin disk diffusion susceptibility tests: a collaborative study.

A multilaboratory in vitro study was carried out to determine disk diffusion susceptibility testing quality control limits for two new semisynthetic penicillins, mezlocillin and piperacillin. Existing limits for carbenicillin and ampicillin were reevaluated. Multiple tests (which followed standards set by the National Committee for Clinical Laboratory Standards ASM-2 revised) were performed in nine laboratories by different technologists using disks and Mueller-Hinton agar from different manufacturers. Clinically significant differences between disks produced by different manufacturers were not noted. Inhibitory zone diameter measurements from all laboratories were analyzed, and upper and lower control limits were established by using the overall median +/-0.5 the median range of the individual laboratory measurements as determining parameters. Close agreement of the data in this study with the results of national proficiency testing and quality control programs for ampicillin and carbenicillin supports the validity of our approach to making initial recommendations for quality control guidelines for new antimicrobial agents.

Ampicillin↗
PubMed1981

Summary and analysis of the mycology proficiency testing survey results of the College of American Pathologists. 1976-1979.

The results of the CAP Mycology Proficiency Testing Survey Programs for 1976 through 1979 are summarized and analyzed. There has been a slight, but definite, improvement in participant performance over this four year period and considerable improvement over the performance of 1972. The problems in analyzing participant performance are reviewed. The Survey Program itself is examined in the light of the stated objectives, and areas for improvement noted.

Aspergillus flavus↗
PubMed1980

Cefoperazone (T-1551), a new semisynthetic cephalosporin: comparison with cephalothin and gentamicin.

The in vitro activity of cefoperazone (T-1551) against almost 9,000 recent clinical isolates at six institutions was tested and compared with that of cephalothin and gentamicin. The modal minimum inhibitory concentrations of cefoperazone were 16- and 4-fold less than those of cephalothin and gentamicin, respectively, against 5,503 strains of Enterobacteriaceae. Species normally resistant to cephalothin, such as indole-positive protease and enterobacters, were almost universally susceptible to cefoperazone. Cefoperazone demonstrated activity comparable to gentamicin against Pseudomonas aeruginosa and other pseudomonads.

Bacteria↗
PubMed1980

Moxalactam (LY127935), a new semisynthetic 1-oxa-beta-lactam antibiotic with remarkable antimicrobial activity: in vitro comparison with cefamandole and tobramycin.

Moxalactam (LY127935) exhibited greater in vitro activity than cefamandole and tobramycin against clinical isolates of Enterobacteriaceae, Aeromonas hydrophila, and Pseudomonas maltophilia. The activities of the three drugs against other microorganisms were as follows: for staphylococci, cefamandole = tobramycin greater than moxalactam; for streptococci, cefamandole greater than moxalactam greater than tobramycin; and for Pseudomonas aeruginosa, tobramycin greater than moxalactam greater than cefamandole. Moxalactam also demonstrated significant activity against the Bacteroides fragilis group and other anaerobes. Moxalactam was comparable to cefotaxime (HR756) in its inhibition of cephalothin-resistant and aminoglycoside-resistant clinical isolates.

Aminoglycosides↗
PubMed1980

Cefotaxime: in vitro activity and tentative interpretive standards for disk susceptibility testing.

Tested against 9,412 recent clinical isolates, cefotaxime exhibited 8 to 64 times greater activity against the Enterobacteriaceae than did cephalothin and two to four times greater activity against Pseudomonas aeruginosa, but only one-half to one-eighth the activity of cephalothin against staphylococci. Using 420 different clinical isolates, but with comparable minimal inhibitory concentration (MIC) distributions, disk diffusion-MIC regression analyses were performed, using 5- and 30-micrograms cefotaxime disks. Cefotaxime MIC susceptible and resistant breakpoints of less than or equal to 8 and greater than 32 micrograms/ml are tentatively proposed. Based on the MIC breakpoints, the data showed the best discrimination among the three susceptibility categories (susceptible, indeterminate, and resistant) when the 30-micrograms cefotaxime disk was used. The zone diameter breakpoints as determined by the error rate-bounded method and regression analysis were greater than or equal to 23 mm for susceptible, 15 to 22 mm for indeterminate, and less than or equal to 14 mm for resistant.

Bacteria↗