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Biomedical subjects

G D Roberts

Publications and source records attributed to G D Roberts.

At least 109 records · Page 6Linked to original sources
PubMed1984

Epidemic of pulmonary blastomycosis (Namekagon fever) in Wisconsin canoeists.

Epidemics of pulmonary blastomycosis have rarely been reported. The following epidemic occurred in a Minnesota family and several of their acquaintances after a canoeing trip in northwestern Wisconsin. The common exposure area was most likely a campsite, located along the upper reaches of the Namekagon River. The Namekagon River Valley is a known endemic area of Namekagon fever (blastomycosis) in dogs. Approximately one month after returning home, five of the eight members of the group had positive direct microscopic examinations and cultures of Blastomyces dermatitidis from their sputa, as well as abnormalities on their chest roentgenograms. Among these five patients, four were symptomatic, with fever, cough, and pleuritic chest pain. Of the three others, one had pleuritic chest pain with a transient lung infiltrate, the second was asymptomatic with a transient lung infiltrate, and the third was asymptomatic with a normal chest roentgenogram. Results of acute serologic tests (complement fixation and immunodiffusion) were negative in all five patients evaluated. None of the patients received antifungal therapy. Follow-up five years after the epidemic revealed that all eight were in excellent health, and none had evidence of continuing pulmonary or extrapulmonary disease.

Adult↗
PubMed1983

Retrospective comparison of three blood culture media for the recovery of yeasts from clinical specimens.

In a retrospective fashion, two different blood culture bottles with biphasic brain heat infusion media, one permanently and the other transiently vented, were compared to a transiently vented tryptic soy broth blood culture bottle for the recovery of yeasts from blood. A total of 95 isolates of Candida species and 19 isolates of Cryptococcus neoformans were recovered, of which 95% were from the permanently vented biphasic medium bottle incubated at 30 degrees C, 57% were from the transiently vented biphasic medium bottle incubated at 35 degrees C, and 45% were from the transiently vented tryptic soy broth bottle incubated at 35 degrees C. In 81% of the patients with candidemia, yeasts were detected either only (50%) or earlier (31%) in the permanently vented biphasic blood culture bottle. The mean recovery time was shorter in both biphasic media compared to the tryptic soy broth bottle. Cryptococcus neoformans was not recovered from the transiently vented broth, and less than 50% of the isolates of Candida glabrata and Cryptococcus neoformans grew in the transiently vented biphasic bottle. The results suggest that when fungemia is suspected, the use of a permanently vented biphasic bottle incubated at 30 degrees C will increase the recovery rate of yeasts from blood and that the transiently vented biphasic bottle and tryptic soy broth bottle are less satisfactory for this purpose.

Candida↗
PubMed1983

Corrected version specificity of the latex test for cryptococcal antigen: a rapid, simple method for eliminating interference factors.

An enzymatic method involving a protease (pronase) for the elimination of interference factors in the latex test for cryptococcal antigen was developed and compared with dithiothreitol treatment. The two were equivalent in their ability to remove interference factors; however, the enzymatic method generally yielded higher titers. The method is simple, requires only 20 min, and makes the latex test for cryptococcal antigen specific.

Journal Article↗
PubMed1983

Comparison of a radiometric method (BACTEC) and conventional culture media for recovery of mycobacteria from smear-negative specimens.

The BACTEC system and three conventional media (Middlebrook 7H10, selective Middlebrook 7H11 [S7H11], and Lowenstein-Jensen [LJ] were compared for their mean recovery times and recovery rates of mycobacteria from acid-fast, smear-negative clinical specimens. Of the 71 smear-negative, culture-positive specimens recovered from 2,165 submitted smear-negative cultures, the BACTEC system detected 71.8%, compared with 88.7% for the conventional three-medium system. When media were individually compared, BACTEC medium (Middlebrook 7H12) was more successful in recovering mycobacteria (71.8%) than was LJ (62%), Middlebrook medium 7H10 (55.9%), or Middlebrook S7H11 medium (52.1%). Middlebrook 7H11 medium containing sodium selenate was also evaluated and did not increase the recovery rate or decrease the recovery time of mycobacterial species when compared with LJ, Middlebrook 7H10, S7H11, and 7H12 media. The mean detection time for the BACTEC system was less than that by conventional methods for the seven species of mycobacteria recovered. Detection times for Mycobacterium tuberculosis on the BACTEC system and conventional cultural systems were 13.7 and 26.3 days, respectively.

Bacteriological Techniques↗
PubMed1983

Evaluation of a lysis-centrifugation system for recovery of yeasts and filamentous fungi from blood.

A lysis-centrifugation system (Isolator; E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.) was compared with a biphasic brain heart infusion (BHI) medium in a prospective study of 5,125 fungal blood cultures. The Isolator recovered 90.3% of the positive cultures, compared with 63.4% recovered by the biphasic BHI medium. Overall, the detection of fungemia was increased 36.6% by the Isolator. Mean recovery times for yeasts were 2.12 and 4.90 days for the Isolator and BHI bottles, respectively. Cultures of Histoplasma capsulatum required 8.0 and 24.14 days for recovery by the Isolator and BHI bottles, respectively. The Isolator provided a more rapid and sensitive means of detecting organisms associated with fungemia.

Blood↗
PubMed1983

Evaluation of the BACTEC radiometric method for recovery of mycobacteria and drug susceptibility testing of Mycobacterium tuberculosis from acid-fast smear-positive specimens.

A total of 463 respiratory specimens, all smear positive for acid-fast bacteria, were inoculated onto routine solid media and into BACTEC 7H12 Middlebrook medium for detection of mycobacterial growth. Conventional drug susceptibility testing (1% proportion method) was performed on Middlebrook 7H10/7H11 medium, and radiometric susceptibility testing was performed on BACTEC 7H12 medium. The average detection times for BACTEC-positive cultures were 8.3 days for Mycobacterium tuberculosis and 5.2 days for mycobacteria other than tuberculosis; by conventional methods, they were 19.4 and 17.8 days, respectively. These detection times do not include time required for identification, which was done by the conventional method only. There was an excellent correlation in the recovery rates of mycobacteria by the two methods. Drug susceptibility test results of M. tuberculosis isolates by the two methods showed 95.1 to 100% overall agreement. The average reporting time for drug susceptibility results ranged from 4.2 to 6.9 days for the BACTEC method and 13.7 to 21 days for the conventional methods. An average of 18 days was required by the BACTEC method for complete recovery and drug susceptibility testing of M. tuberculosis, as compared with 38.5 days for the conventional methods.

Bacteriological Techniques↗
PubMed1983

Bacteremia due to Mycobacterium avium-intracellulare in the acquired immunodeficiency syndrome.

The presence of Mycobacterium avium-intracellulare has frequently been demonstrated in tissue specimens from patients with the acquired immunodeficiency syndrome. The importance of this mycobacterium as a cause of constitutional symptoms and organ dysfunction has been unclear, however, because of the sparse inflammatory response evoked and the frequent concurrence of other pathogenic organisms. We detected M. avium-intracellulare in blood samples from eight patients with the acquired immunodeficiency syndrome, seven of whom had a previously recognized M. avium-intracellulare infection. Blood cultures were positive on 1 to 14 occasions over 135 days using the Dupont isolator system or the Bactec 12B medium system. Cultures were positive within 14 to 51 or 7 to 14 days with the respective techniques. The ability to rapidly isolate M. avium-intracellulare from blood may provide a useful diagnostic technique for detecting disseminated mycobacterial disease in patients with the acquired immunodeficiency syndrome as well as in other patient populations. This technique may also be useful for assessing the efficacy of drug therapy.

Acquired Immunodeficiency Syndrome↗
PubMed1983

Mycobacteremia and the new blood culture systems.

Clinical and microbiologic aspects of mycobacteremia occurring in 11 patients are presented. Ten of the 11 patients were immunosuppressed. Disseminated disease was shown in 7 patients, transient bacteremia in 2, and endocarditis in 1. Blood cultures were positive in 11 blood culture systems. Newer blood culture systems appear to provide more rapid detection of mycobacteremia.

Adolescent↗
PubMed1983

Invasive disease caused by Trichosporon beigelii.

An immunocompromised patient had cellulitis that was unresponsive to conventional antimicrobial therapy. Skin biopsy specimens and fungal blood cultures revealed the offending organism as Trichosporon beigelii. Recognition of this opportunistic pathogen in immunocompromised patients is important.

Humans↗
PubMed1982

In vitro synergistic activity of ethambutol, isoniazid, kanamycin, rifampin, and streptomycin against Mycobacterium avium-intracellulare complex.

Strains of Mycobacterium avium-intracellulare complex often exhibit in vitro resistance to common antimycobacterial agents. Combinations of etambutol, isoniazid, kanamycin, rifampin, and streptomycin were tested to determine if synergism occurred. Ninety-six percent of the strains were susceptible to a combination of ethambutol and rifampin at concentrations attainable clinically. Other combinations of antimycobacterial agents inhibited 4 to 82% of the isolates tested.

Antitubercular Agents↗
PubMed1982

Identification of clinical isolates of mycobacteria with gas-liquid chromatography: a 10-month follow-up study.

Identification of routine mycobacterial isolates by gas-liquid chromatography profile analysis was performed on 335 strains received at the Mayo Clinic over a 10-month period. Comparison of identification by gas-liquid chromatography versus conventional biochemical profiles was made. The two methods agreed on the identification of 320 isolates, with gas-liquid chromatography profiling making eight errors and biochemical profiling making four errors. In three cases, discrepancies could not be resolved.

Chromatography, Gas↗
PubMed1982

Specificity of the latex test for cryptococcal antigen: a rapid, simple method for eliminating interference factors.

An enzymatic method involving a protease (pronase) for the elimination of interference factors in the latex test for cryptococcal antigen was developed and compared with dithiothreitol treatment. The two were equivalent in their ability to remove interference factors; however, the enzymatic method generally yielded higher titers. The method is simple, requires only 20 min, and makes the latex test for cryptococcal antigen specific.

Antigens, Fungal↗
PubMed1980

Nosocomical Rhizopus infection (zygomycosis) in children.

Three children with the rare occurrence of zygomycosis are descibed: two had involvement of a solitary lesion of gangrenous cellulitis on the buttocks, and th third was a neonate with gastric performation and a gangrenous appendicitis. All three patients were compromised hosts (two with leukemia and one a premature infant with respiratory distress syndrome). All three patients appeared to have acquired the same organism. Rhizopus oryzae, from the same fomites, elastic bondages (Elastoplast). The Center for Disease Control has received several other reports of zygomycosis traceable to the same material. Alll three of our patients were cured of their infections. Early diagnosis and a combined surgical and chemotherapeutic approach appear to prevent death from zygomycosis.

Amphotericin B↗
PubMed1980

Laryngeal presentation of blastomycosis.

Systemic blastomycosis may rarely involve the larynx, and it most likely is a result of hematogenous dissemination or direct inoculation from a currently or previously active pulmonary infection. Often, laryngeal blastomycosis has been confused with squamous cell carcinoma because of the clinical and histopathologic similarities, and this confusion has led to inaccurate diagnosis and inappropriate therapy. The etiologic agent, Blastomyces dermatiditis, may be seen in infected tissue with routine and special stains; however, cultural proof remains the sine qua non for diagnosis.

Adult↗
PubMed1980

Rhodotorula septicemia: two cases and a review of the literature.

Rhodotorula glutinis var. glutinis was isolated from the blood of two patients who were seriously ill and required long-term intravenous therapy. Although both isolates were sensitive to amphotericin B and 5-fluorocytosine, neither patient received antifungal therapy. One of the two patients died, but Rhodotorula was not recovered at autopsy. Review of the literature shows that Rhodotorula septicemia is often associated with contamination of intravenous infusion equipment, resulting in toxemia and hypotension. Initial therapy for fungemia should consist of removal of infected cannulas and fluid replacement. If fungemia persists, antifungal drug therapy should be considered.

Adult↗