Teaching pathology to medical students in the 1990s: a 1989 symposium of the Association of Pathology Chairmen.
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Curriculum↗
Biomedical subjects
J M Matsen
Publications and source records attributed to J M Matsen.
Comparative activity of cefepime, alone and in combination, against clinical isolates of Pseudomonas aeruginosa and Pseudomonas cepacia from cystic fibrosis patients.
The comparative in vitro activity and synergy of cefepime were evaluated with clinical isolates of Pseudomonas aeruginosa and Pseudomonas cepacia from cystic fibrosis patients. The activity of cefepime, both alone and in combination, was comparable to those of other antibiotics. The clinical efficacy of cefepime in cystic fibrosis patients merits investigation.
Anti-Bacterial Agents↗
In vitro activities of cefoperazone and sulbactam singly and in combination against cefoperazone-resistant members of the family Enterobacteriaceae and nonfermenters.
Among 28,000 isolates of the family Enterobacteriaceae and nonfermenters isolated at multiple medical centers, 1,084 (4%) were resistant to cefoperazone (MIC, greater than or equal to 64 micrograms/ml) and 1,711 (6%) exhibited cefoperazone MICs of 2 to 32 micrograms/ml. Ninety-six percent of these 2,795 isolates produced beta-lactamase, as determined by the nitrocefin test. Sulbactam alone (8 micrograms/ml) was inactive against 99.6% of the isolates other than Acinetobacter calcoaceticus and Pseudomonas cepacia. Sulbactam enhanced the activity of cefoperazone against 56% of the isolates of the family Enterobacteriaceae and 44% of the nonfermenters. In the presence of sulbactam concentrations of less than or equal to 8 micrograms/ml, 65% of the cefoperazone-resistant isolates had reductions in cefoperazone MICs of greater than or equal to 2 log2 dilution steps and were susceptible to less than or equal to 32 micrograms/ml. Antagonism was not observed.
Bacteria↗
In vitro activities of combinations of aztreonam, ciprofloxacin, and ceftazidime against clinical isolates of Pseudomonas aeruginosa and Pseudomonas cepacia from patients with cystic fibrosis.
The in vitro activities of two-drug combinations of aztreonam, ciprofloxacin, and ceftazidime were studied in 96 clinical isolates of Pseudomonas aeruginosa and in 20 clinical isolates of Pseudomonas cepacia from cystic fibrosis patients. Some synergy was observed with each combination used against P. aeruginosa, but synergy was rare when the combinations were used against P. cepacia.
Aztreonam↗
The frequency of bacterial pathogens in infections potentially preventable by antimicrobial prophylaxis.
Bacterial pathogen frequency was analyzed over a fourteen year period at the University of Utah Medical Center. Isolation techniques and identification procedures have remained essentially the same during this period, allowing for a valid comparison of this frequency. For most organisms the frequency of overall isolation had remained relatively stable. Differences were seen in the frequency of Pseudomonas aeruginosa and in the isolation rate of Staphylococcus aureus. Escherichia coli became proportionately less frequent, almost as an adjustment to the increase in Pseudomonas aeruginosa. A table is presented of these same pathogens and their likelihood to occur in post-operative patients categorized by surgery type in order to define their role in such infections potentially preventable by antimicrobial prophylaxis.
Anti-Bacterial Agents↗
The use of aztreonam in the cystic fibrosis patient.
Eradication of pulmonary infection by Pseudomonas aeruginosa in cystic fibrosis (CF) patients has long presented a significant challenge to the medical community. Many antimicrobial agents have proved incompletely effective against this persistent pathogen, and even the aminoglycosides, which represent the traditional therapy for such infections, have been associated with considerable toxicity and resistance. The monobactam antibacterial agent aztreonam is used both as single-agent therapy and in combination with other drugs. Several controlled, clinical trials have demonstrated the efficacy of aztreonam in the treatment of CF patients with pulmonary exacerbations caused by P. aeruginosa. The only side effect of aztreonam therapy commonly encountered in these studies was elevation of hepatic transaminase concentrations; this effect was of uncertain significance. It was concluded that aztreonam may offer clinical efficacy comparable to that provided by the combination of tobramycin plus azlocillin. Further, there does not seem to be any appreciable difference in the development of resistance to aztreonam compared with traditional therapies.
Aztreonam↗
Changing susceptibility of Pseudomonas aeruginosa isolates from cystic fibrosis patients with the clinical use of newer antibiotics.
To detect a change in antibiotic susceptibility patterns in Pseudomonas aeruginosa isolates upon the introduction and clinical use of ciprofloxacin, aztreonam, and ceftazidime, MICs for clinical isolates collected before introduction of the antibiotics, during early clinical use, and later were determined for these and seven other antipseudomonal antibiotics. Concomitant resistance to two or more antibiotics was also studied. Over the three study periods, rates of susceptibility to 9 of the 10 antibiotics decreased. The largest decrease occurred with ceftazidime. Analysis of subsets of isolates from patients treated with ciprofloxacin or aztreonam also showed declining susceptibility to the latter but a stabilization of susceptibility to the former after an initial decline. Concomitant resistance within and among antibiotic classes was common.
Anti-Bacterial Agents↗
Evaluation of four newer antimicrobial agents in the Avantage susceptibility test system.
Antimicrobial elution disks containing amoxicillin-clavulanic acid (Augmentin), cefotetan, ciprofloxacin, or norfloxacin were tested in the Avantage automated susceptibility test system. Performance was compared against an agar diffusion procedure in a three-site collaborative study. Results of 1,500 comparison with amoxicillin-clavulanic acid showed a full accord (agreement of both systems) of 93.6% and an essential accord (agreement excluding minor discrepancies) of 97.6%. Results for cefotetan showed a full accord of 95.1% and an essential accord of 98.3% by the two methods. Results for both ciprofloxacin and norfloxacin were in full accord for more than 98% of tests with gram-negative bacilli and staphylococci, but tests with enterococci gave 38 and 26.1% minor discrepancies (the result of one method was resistant or susceptible and the result of the other method was intermediate), respectively. The results indicated that the Avantage test system is accurate and reliable and provides appropriate determination of bacterial susceptibility with the four antibiotics tested.
Amoxicillin↗
Review of urine microscopy for bacteriuria.
Urine microscopy for bacteriuria remains a useful and valid technique for the evaluation of urinary tract infection; however, established interpretive criteria are not agreed on. Our own data and a review of the literature demonstrate that reliable data can be obtained by enumerating the organisms observed in stained or unstained centrifuged and stained uncentrifuged urine specimens. Criteria are given for the interpretation of urine microscopy for maximum sensitivity and specificity for each method reviewed. For clinicians desiring to perform urine microscopy, we recommend the use of oil-immersion microscopy of Gram-stained centrifuged urine sediment and suggest that observing at least one organism per oil-immersion field corresponds with 95% sensitivity and that observing more than five organisms corresponds with 95% specificity for bacteriuria at a level of 10(5) or more colony-forming units per milliliter. Further testing will be required on any negative specimen from a symptomatic patient.
Bacteriological Techniques↗
Pyrolysis mass spectrometry of bacteria from infected human urine. I. Influence of culturing and antibiotics.
Curie-point pyrolysis mass spectrometry was performed on three bacterial isolates obtained from infected human urine using a novel, direct isolation method. Bacterial samples were analysed directly after isolation, as well as after free growth in broth and after exposure to solutions containing penicillin and gentamicin. The spectra of bacteria directly from urine showed no detectable contamination from urinary constituents. Discriminant analysis indicated genetic strain differences to be greater than the combined variances due to sample preparation or the growth phase. Characteristic biochemical changes related to growth or non-growth were detectable after only 2 h of incubation. The potential usefulness of pyrolysis mass spectrometry techniques for rapid susceptibility testing is discussed.
Anti-Bacterial Agents↗
Evaluation of the Wayson variation of a methylene blue staining procedure for the detection of microorganisms in cerebrospinal fluid.
Meningitis of bacterial origin is a severe infection that must receive immediate attention and prompt treatment. We evaluated a basic fuchsin-methylene blue, ethyl alcohol-phenol staining procedure (Wayson stain) and compared it with the Gram stain procedure for evaluation of cerebrospinal fluid. All smears were prepared within 30 min of receiving the specimen and examined without knowledge of the results of the companion smear or culture. Of 546 specimens entered into the study, 84 were culture positive. Based on the culture results, the sensitivity and specificity of Wayson stain were 90 and 98%, respectively, compared with 73% sensitivity and 99% specificity by Gram stain. We observed that Wayson staining is a particularly sensitive method for screening clinical specimens that contain proteinaceous background material. The Wayson staining procedure is a simple and sensitive technique for early detection of meningitis.
Bacteriological Techniques↗
Bacteriuria with intestinal loop urinary diversion in children.
Bacteriuria and intestinal loop urinary diversion with open (refluxing) ureterointestinal anastomoses did not prevent normal renal and body growth in 44 children, who were followed for 55.2 months. A comparison of the long-term use of sulfamethoxazole and nitrofurantoin with no treatment showed no statistically significant changes in the stoma, loop residual, renal function, serum electrolytes and treatment or prevention of bacteriuria.
Adolescent↗
Evaluation of cefaclor and amoxycillin in the treatment of acute otitis media.
Twenty-eight patients with acute otitis media were treated in a random double blind manner with either amoxycillin or cefaclor. The predominant organisms isolated were H. influenzae and S. pneumoniae. All patients responded satisfactorily except one, treated with cefaclor, whose compliance with the regimen was very doubtful. One instance of mild elevation of SGOT and one case of mild erythematous rash occurred in each treatment group. In this limited study, cefaclor appeared comparable to amoxycillin in the treatment of acute otitis media.
Acute Disease↗
Comparison of micro-ID, API 20E, and conventional media systems in identification of Enterobacteriaceae.
The Micro-ID, a new identification kit for Enterobacteriaceae, consists of 15 biochemical tests, with substrates and reagents impregnated in filter paper disks. A 0.2-ml amount of an organism suspension equal to a 0.5 McFarland standard is pipetted into each of the compartments. After 4 h of incubation and addition of potassium-hydroxide (KOH) to the Voges-Proskauer test, the color reactions are read according to the recommendations of the manufacturer. A five-digit octal code number is derived from each set of reactions from which an identification is derived by using a code book. In a single-blind, comparative study of the Micro-ID system with the API 20E system (Analytab Products Inc.) and conventional biochemical tube media, we found that the Micro-ID and the API 20E systems gave a 90% identification correlation when each was compared with the conventional tube media. A comparison of all three systems gave an 82% overall identification correlation. When the common tests of Micro-ID and API 20E were compared with conventional tube media, we found that the tests in the Micro-ID performed as well as or better than those of the API 20E. Certain groups of organisms, i.e., Citrobacter, Enterobacter, Proteus, Salmonella, and Serratia genera, were found to give low correlation on certain common tests. When using primary isolation MacConkey plates from the clinical laboratory, only 74% of the plates with Enterobacteriaceae had sufficient numbers of colonies of each enteric organism to produce the 0.5 McFarland inoculum density required. Problems concerning the misidentification of some organisms are discussed.
Bacteriological Techniques↗
Problems that merit investigation in clinical microbiology laboratories.
Research is needed in the following areas in clinical microbiology: specimen collection, microbial identification, automation and instrumentation, rapid microbial diagnoses, microbial metabolism, computerization, relevance and laboratory utilization, physician influence, training in clinical microbiology, media and reagents, quality control, and antimicrobial susceptibility and assay determinations. For optimal progress in many of these categories, federal funding should be made available.
Humans↗
Oxolinic acid therapy for urinary tract infections in children.
Thirty hospitalized children with Gram-negative bacillary urinary tract infections were treated with oxolinic acid for 14 to 21 dyas. Fifteen of 17 patients with uncomplicated and 11 of 13 with complicated urinary infections had favorable bacteriologic responses. Resistant organisms developed in four treatment failures. Oxolinic acid urine concentrations were well above the minimal inhibitory concentration for most strains of Escherichia coli, Klebsiella, Enterobacter, Proteus mirabilis, P vulgaris, P morganii, and P rettgeri. Approximately half of these patients experienced mild symptoms possibly related to oxolinic acid therapy; in no instance did they require cessation of therapy. Our experience indicates that if the urine is not sterile by the end of five days of treatment, bacterial resistance to oxolinic acid is likely to have developed, and therapy with another agent should be considered and antibiotic susceptibility tests repeated.
Adolescent↗
Automated, rapid identification of bacteria by pattern analysis of growth inhibition profiles obtained with Autobac 1.
A scheme for identifying bacteria has been devised which utilizes the inhibition patterns obtained by Autobac 1 with routine and unusual antimicrobial agents and with other differentially inhibitory chemical compounds. Over 600 compounds were initially identified from the literature, and over 125 of these were selected for further testing on the basis of antibacterial activity most conducive to the instrument-generated differential scheme. Numerical growth index information derived by light scatter comparisons from the instrument were analyzed by computer, utilizing the quadratic discriminant function statistical technique. In comparison with conventional methods, accuracy for the 10 bacterial genera studied was 95% or greater. Results indicate a potential for both bacterial identification and antimicrobial agent susceptibility testing in the clinical laboratory within 3 to 5 h when using this automated approach.
Acinetobacter↗
Microwave oven irradiation as a method for bacterial decontamination in a clinical microbiology laboratory.
Exposure of 10 frequently isolated clinical pathogens to microwave irradiation resulted in total sterilization with 60 s. Time exposure experiments done with commercially prepared test strips containing Bacillus stearothermophilus spores indicated that 5-min exposure was adequate to insure sterility of small, contaminated loads.
Bacillus subtilis↗