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D J Blazevic

Publications and source records attributed to D J Blazevic.

At least 19 recordsLinked to original sources

Evaluation of serum arabinitol as a diagnostic test for candidiasis.

Gas-liquid chromatography was used to quantitate the arabinitol concentration in the sera of patients with candidiasis and in that of control patients. Serum arabinitol was elevated in 59% (n = 34) of patients with Candida sepsis, in 39% (n = 38) with Candida colonization, in 14% (n = 62) with bacterial sepsis, and in 0% (n = 11) of normal persons. The above patients were subsequently divided on the basis of renal function. Of those with decreased renal function, serum arabinitol was elevated in 89, 92, and 50% of patients with Candida sepsis, Candida colonization, and bacterial sepsis, respectively. Of those with normal renal function, serum arabinitol was elevated in only 23 and 14% of patients with Candida sepsis and Candida colonization, respectively. When serum arabinitol/creatine ratios were calculated for patients with both increased arabinitol and increased creatinine, elevated ratios were obtained in 69, 36, and 0% of patients with Candida sepsis, Candida colonization, and bacterial sepsis, respectively.

Candidiasis

Medium for selective isolation and presumptive identification of the Bacteroides fragilis group.

We developed and evaluated a new medium (FRAG agar) for the selective isolation and presumptive identification of the Bacteroides fragilis group. This medium contains 1% D-glucuronic acid as a fermentable carbon source, a reduced peptone content, gentamicin, and 20% bile. Presumptive identification of the B. fragilis group was based on growth, fermentation, and typical colony morphology. A total of 75 stock culture isolates of the B. fragilis group grew well on this medium, and 69 showed evidence of fermentation. Of 90 other anaerobes, none grew well or fermented glucuronic acid. In a clinical trial of 100 specimens sent for anaerobic culture, FRAG agar inhibited 71 of 71 anaerobes not belonging to the B. fragilis group, as well as 104 of 110 facultative organisms. A total of 33 isolates of the B. fragilis group were recovered on the selective medium, whereas only 23 were recovered by routine methods. Of 23 cultures positive for the B. fragilis group on routine plates, 22 were positive on FRAG agar.

Bacteriological Techniques

Rapid biotyping of Haemophilus influenzae and Haemophilus parainfluenzae with PathoTec strips and spot biochemical tests.

PathoTec strips and spot biochemical tests were evaluated for the ability to biotype Haemophilus influenzae and Haemophilus parainfluenzae. Indole, urease, and ornithine decarboxylase reactions were tested. The results of PathoTec strips compared favorably with those conventional methods; the percent agreements were as follows: indole, 100; urease, 99.5; and ornithine, 95.5. Spot tests were simple and rapid, and the results also compared favorably with those of conventional tests; the percent agreements were as follows: indole, 99; urease, 100; and ornithine, 96.

Bacteriological Techniques

Comparison of the API 20E and Corning N/F systems for identification of nonfermentative gram-negative rods.

A total of 231 strains of nonfermenting gram-negative rods were tested on the API 20E system, the Corning N/F system, and conventional media. When the results of identification to species were compared, the API system agreed with the conventional system on 69% of the isolates, and the Corning system agreed with the conventional system on 79% of the isolates. Both kit systems were deficient in identifying Pseudomonas cepacia and the more unusual isolates.

Bacterial Infections

Comparison of Micro-ID and API 20E systems for identification of Enterobacteriaceae.

The Micro-ID 4-h identification system for Enterobacteriaceae was compared to the API 20E overnight method, using 230 fresh clinical isolates and 74 stock cultures. Agreement was 97.8% for the clinical isolates and 93.2% for the stock cultures. Eighty-seven percent of primary culture plates containing gram-negative rods yielded sufficient growth to perform the 4-h Micro-ID identification on the same day the organisms were isolated.

Bacteriological Techniques

Comparison of three methods for identifying nonfermenting gram-negative rods.

Seventy-six strains of nonfermenting gram-negative rods were tested on the Analytab Products, Inc. (API) system and on conventional media. In addition, 51 strains were tested on the Oxi-Ferm system. When the identification results were compared, the API agreed with the conventional system on 41% of the isolates and Oxi-Ferm agreed with the conventional system on 72% of the isolates. API had the greatest difficulty in identifying Pseudomonas aeruginosa. API and Oxi-Ferm both had difficulty identifying P. cepacia. Oxi-Ferm had more individual discrepant biochemical reactions than did API when compared to the conventional media, but still maintained a higher percentage agreement with the conventional system.

Bacterial Infections

Use of cerebrospinal fluid lactate levels in the diagnosis of bacterial meningitis.

Ninety-two cerebrospinal fluids were analyzed by a simple gas-liquid chromatography method for lactic acid. The presence of greater than 30 mg/dl of lactic acid correlated with proven bacterial or cryptococcal meningitis. Elevated lactate levels were also found in two patients with suspected but not proven bacterial meningitis. In 78 patients who did not have bacterial meningitis the cerebrospinal fluid contained less than 30 mg/dl of lactic acid.

Adult

Rapid speciation of Haemophilus with the porphyrin production test versus the satellite test for X.

The detection of porphyrins produced from omega-aminolevulinic acid was evaluated for use in speciation of the Haemophilus. Two hundred and forty-eight clinical isolates of nonhemolytic Haemophilus were tested concurrently for porphyrin production and for X and V requirements. The porphyrin production test was more rapid (4 h) and more accurate than the satellite test.

Aminolevulinic Acid

Rapid deoxyribonuclease test with methyl green.

A 4-h deoxyribonuclease test using methyl green to differentiate Serratia from other Enterobacteriaceae was developed. The tests agreed 100% with an overnight plate test for 100 Serratia, 83 Enterobacter, and 6 Klebsiella species.

Bacteriological Techniques

Current taxonomy and identification of nonfermentative gram negative bacilli.

In recent years significant advances have been made in the characterization and taxonomy of nonfermentative bacilli as well as in the recognition of their pathogenic potential for man. In addition, certain other infrequently isolated bacteria that may be fermentative have been recognized, and improved methods for their identification have been developed. This discussion attempts to present a practical approach to the identification of these micro-organisms in the clinical microbiology laboratory.

Acinetobacter

Stability of gentamicin in serum.

Patients' sera were divided into three portions when the initial gentamicin level was determined and were stored at -20, 4, and 25 degrees C in plastic or glass tubes. Gentamicin levels were repeated after 1 and 2 days of storage at the respective temperatures. There was no significant difference in gentamicin levels among portions, except those from a patient in renal failure with high serum concentrations of carbenicillin.

Carbenicillin

Antibiotic susceptibility of the subspecies of Bacteroides fragilis.

Strains (115) of Bacteroides fragilis were identified at the subspecific level and were tested for susceptibility to ampicillin, cephalothin, chloramphenicol, clindamycin, penicillin, and tetracycline using an agar dilution technique. We tested the following strains: B. fragilis subsp. distasonis, 12; B. fragilis subsp. fragilis, 39; B. fragilis subsp. ovatus, 10; B. fragilis subsp. thetaiotaomicron, 32; B. fragilis subsp. vulgatus, 10; and B. fragilis subsp. "other," 12. There were no marked differences in susceptibility between the subspecies. One strain of B. fragilis subsp. thetaiotaomicron had a minimal inhibitory concentration of 12.5 mug/ml for clindamycin, but all other strains were susceptible. All the strains were susceptible to chloramphenicol. Susceptibility to tetracycline was variable. Only a few strains were susceptible to the penicillins and cephalothin.

Anti-Bacterial Agents

Toxicity of nalidixic acid on candida albicans, Saccharomyces cerevisiae, and Kluyveromyces lactis.

The antibacterial drug nalidixic acid (Nal) can suppress the growth of Candida albicans at levels of the drug normally found in urine. Growth suppression increases as drug levels are increased, and Nal also causes a similar proportional inhibition of the synthesis of all cellular macromolecules. However, growth temperature (25 versus 37 C) and the divalent cations Mg(2+) and Mn(2+) can increase C. albicans resistance to Nal. Also, nitrogen depletion of Candida shows that Nal-treated and untreated cells exhibit no difference in leucine uptake during readaptation to nitrogen. In Nal-treated, nitrogen-starved cells, ribonucleic acid and deoxyribonucleic acid (DNA) biosynthesis are less affected than in unstarved Nal-treated cells, but of the two nucleic acids DNA synthesis is the most affected. Nal-resistant strains of C. albicans exhibit a slight toxicity for macromolecular synthesis. Nal treatment of a synchronized population of Saccharomyces cerevisiae results in an increase in the culture mean doubling time of, at most, 20%, but Nal causes the loss of synchronous cell division. With a synchronized population of Kluyveromyces lactis, Nal causes an increase in the mean doubling time of upwards of 300%, with synchrony of cell division being maintained. It is known that S. cerevisiae asynchronously synthesizes mitochondrial DNA during the cell cycle, whereas with K. lactis it is synchronous. Thus, with C. albicans Nal toxicity is dependent both on the dose and the physiological state of the cell. Furthermore, Nal inhibits growth of yeast with synchronous mitochondrial DNA synthesis more adversely than yeast with asynchronous mitochondrial DNA synthesis.

Ascomycota

Rapid fermentation testing of anaerobic bacteria.

Rapid tests for glucose, maltose, lactose, sucrose, and starch fermentation were performed on 112 strains of anaerobic bacteria. The tests were incubated under aerobic conditions, and results were read within 4 h. An overall correlation of 89% was achieved between the rapid tests and the Virginia Polytechnic Institute method.

Anaerobiosis

Significance of urinary isolates of coagulase-negative Micrococcaceae.

Of 16,347 urine cultures submitted to the hospital laboratory, 68 (0.4%) specimens from 50 patients yielded greater than 10(4) coagulase-negative staphylococci/ml in pure culture. A total of 62 of 63 organisms available for study were staphylococci: 45 Staphylococcus epidermidis (predominantly subgroup 1), 15 Staphylococcus saprophyticus (subgroup 3), and 2 Staphylococcus aureus. Twenty-one patients had "probable" urine infections. Eight patients had two or more positive urine cultures, and all isolates from the same patients were identical (by morphology, antibiotic susceptibility, and hemolytic pattern). Nine (75%) of the 12 isolates of S. saprophyticus, which were novobiocin resistant and nonhemolytic on the synergistic hemolysis test, were from patients with probable urinary infection. Eight were young women with acute symptoms and pyuria. Differences in the glucose and mannitol fermentation tests with different media may lead to difficulties in identification. Novobiocin resistance cannot be relied upon to differentiate isolates of S. saprophyticus from S. epidermidis.

Adolescent