Publications by authors named "Yajko D"

Article Synopsis
  • HIV-1 RNA quantification is crucial for monitoring therapy effectiveness, and new ultrasensitive assays like Bayer Quantiplex bDNA 3.0 and Roche Amplicor 1.5 have improved viral load detection.
  • The bDNA 3.0 assay shows about double the quantification compared to the older bDNA 2.0 assay and correlates well with the Amplicor 1.5 results.
  • Cost analysis indicates that using the bDNA 3.0 assay is more economical compared to the Amplicor 1.5 assay when considering labor, disposables, and biohazard waste.
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To determine if microbiologic cure of AIDS-related disseminated Mycobacterium avium complex (MAC) is possible in patients receiving highly active antiretroviral therapy (HAART), 4 patients with a history of disseminated MAC received >/=12 months of macrolide-based antimycobacterial therapy. All were asymptomatic and had absolute CD4 cell count >100/microL (range, 137-301) and <10,000 copies/mL of human immunodeficiency virus RNA (range, <500-1250). A bone marrow aspirate and peripheral blood were obtained for mycobacterial culture.

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Article Synopsis
  • The study investigated the large-restriction-fragment patterns of Mycobacterium avium from 85 specimens taken from 25 HIV-infected patients in San Francisco, discovering 4 strains that infected multiple individuals.
  • Most patients had a single strain, but 2 strains were found in 8 patients, though the significance of this dual recovery remains uncertain.
  • The findings suggest that M. avium can spread from the intestinal and respiratory tracts to cause infections, indicating possible common sources or person-to-person transmission.
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Article Synopsis
  • Extrapulmonary pneumocystosis is a rare complication of Pneumocystis carinii pneumonia (PCP), with a significant increase in cases linked to the HIV-1 epidemic.
  • The review covers the history of P. carinii's discovery as a human pathogen, its taxonomic debates, and the epidemiology, highlighting the incidence of extrapulmonary pneumocystosis in HIV-1-infected individuals despite prevalent prophylactic treatments.
  • It also details the clinical features, diagnostic challenges faced by microbiologists, the microscopic presentation of the pathogen, and concludes with a discussion on treatment options.
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Article Synopsis
  • Multidrug therapy is essential for treating Mycobacterium avium complex (MAC) bacteremia in AIDS patients, with suggested drugs including azithromycin, clarithromycin, and rifabutin among others.
  • The study investigated the effectiveness of 132 different drug combinations using various two-, three-, and four-drug therapies against ten MAC strains isolated from AIDS patients.
  • Results indicated that only two specific four-drug combinations were effective against all strains when using a strict susceptibility criterion, while a more lenient criterion revealed more combinations were active against all strains, with variations in effectiveness observed depending on whether the bacteria were in broth or within infected cells.
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An increase in the number of tuberculosis cases caused by multiple-drug-resistant strains of Mycobacterium tuberculosis has stimulated search for new antituberculous agents. Beta-lactam antibiotics, traditionally regarded as ineffective against tuberculosis, merit consideration. Four major penicillin-binding proteins (PBPs) with approximate molecular sizes of 94, 82, 52, and 37 kDa were detected by fluorography of [3H]penicillin-radiolabeled membrane proteins prepared from M.

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A colorimetric method for quantitative measurement of the susceptibility of Mycobacterium tuberculosis to antimicrobial agents is described. The method utilizes an oxidation-reduction dye, Alamar blue, as an indicator of growth. By this method, MICs of isoniazid, rifampin, streptomycin, and ethambutol were determined for 50 strains of M.

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The minimum number of Mycobacterium tuberculosis CFU detectable in clinical sputum specimens by the Amplicor PCR test was estimated by performing the test on duplicate samples of quantitatively cultured serial dilutions of sputum. Positive PCR test results were obtained for all samples that contained 42 CFU of M. tuberculosis.

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Several studies have reported using methods based on polymerase chain reaction (PCR) to detect Mycobacterium tuberculosis in respiratory tract specimens. However, little is known about the actual clinical utility of PCR-based tests, and it is uncertain if PCR technology can be transferred to the clinical laboratory. To determine its utility, we evaluated a commercially developed PCR test system in a clinical laboratory using consecutive respiratory tract specimens.

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As part of an epidemiologic study of Mycobacterium avium complex (MAC) infection in San Francisco, water, food and soil samples were collected from the home environment of 290 persons with human immunodeficiency virus (HIV) infection and cultured for mycobacteria. Isolates recovered from the environment were compared with isolates cultured from study patients. Although mycobacteria were recovered from numerous environmental samples, isolates reactive with MAC-specific DNA probes were recovered from only four of 528 (0.

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In cases of advanced infection with human immunodeficiency virus, mycobacterial blood cultures are frequently used to diagnose disseminated infection with the Mycobacterium avium complex (MAC). However, no prospectively validated guidelines exist for the use of such cultures. In this study, a two-part model for predicting MAC bacteremia was developed and then validated prospectively.

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It is currently recommended that patients with AIDS and Mycobacterium avium complex (MAC) bacteremia receive antimycobacterial treatment. However, no study has prospectively evaluated the impact of this infection and its treatment on survival. This study prospectively followed a cohort of 367 AIDS patients with < or = 50 CD4+ cells/microL and found that MAC bacteremia was independently associated with an increased risk of death (relative hazard [RH] = 1.

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A case-control study was done to determine risk factors for Mycobacterium avium complex (MAC) disease in persons infected with human immunodeficiency virus (HIV) with < 50 CD4+ cells/mm3. In univariate analysis, cases (n = 83) had lower CD4+ cell counts than controls (n = 177) (median, 10 vs. 17/mm3; P < .

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The value of the smear for acid-fast bacilli in predicting pulmonary tuberculosis is unclear in a setting where there is a high prevalence of Mycobacterium avium complex in respiratory specimens. To evaluate the impact of a high prevalence of M. avium complex on the predictive value of the acid-fast bacilli smear for tuberculosis, we reviewed findings on smears and results of cultures over a 3-year period at a hospital where M.

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Mycobacterium avium complex (MAC) is frequently isolated from the respiratory or gastrointestinal tract of patients with advanced human immunodeficiency virus (HIV) infection. Whether they are at increased risk of MAC bacteremia and whether culture of respiratory tract or stool specimens is useful for predicting bacteremia are unclear. HIV-infected patients with < or = 50 CD4+ cells/microL were prospectively studied.

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Patients with AIDS and disseminated Mycobacterium avium complex (MAC) infection received rifampin (600 mg) plus ethambutol (25 mg/kg) plus ciprofloxacin (750 mg) or matching placebos daily for 8 weeks. Patients were monitored every 2 weeks clinically and by quantitating MAC colony-forming units (cfu) per milliliter of blood. Analysis of baseline characteristics revealed no significant differences between groups.

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Various diagnostic tests, both specific and nonspecific, are available in the clinical laboratories for diagnosing human immunodeficiency virus-1 (HIV-1) infection and associated respiratory pathogens. Pneumocystis carinii pneumonia remains the most common pulmonary disease in HIV-1-infected individuals and there have been no significant advances in the laboratory diagnosis of the pathogen beyond the traditional microscopic examination of specimens. In contrast, the greatest revolution in laboratory diagnostic testing has been for mycobacteria, with major advances resulting in significant reduction in the time necessary for isolation and identification to the species level.

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Two independent studies were undertaken to determine the effect of prophylactic treatment with aerosolized pentamidine on the laboratory diagnosis of Pneumocystis carinii pneumonia in individuals at risk for or with the acquired immunodeficiency syndrome. The first study was a retrospective analysis to determine the effect of prophylactic treatment with aerosolized pentamidine on the diagnostic yield and sensitivity of detection of P carinii in induced sputum specimens. The results of examinations of 110 induced sputum specimens from patients who had not received aerosolized pentamidine were compared with the findings in 57 specimens from patients who had.

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The presence of Mycobacterium avium complex (MAC) in stool specimens may be a predictor of disseminated MAC infection, yet the methods for decontaminating stools have not been evaluated for their usefulness in recovering MAC organisms. In the present study, four decontamination methods commonly used to recover acid-fast bacteria from respiratory specimens were compared for their utility in recovering MAC from stool specimens. Ten strains of MAC were used at a level of 10(4) to 10(6) CFU to seed the stool specimens.

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The Premier enzyme immunoassay (Meridian Diagnostics, Inc., Cincinnati, Ohio) was compared with a latex agglutination assay (CALAS; Meridian) for the ability to detect cryptococcal capsular polysaccharide antigen (CrAg) in serum and cerebrospinal fluid (CSF). A total of 594 specimens (471 serum samples and 123 CSF samples) obtained from 430 patients, most of whom were at risk for or had AIDS, were tested in parallel by both systems.

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Current treatments of disseminated infection caused by the Mycobacterium avium-M. intracellulare complex (MAC) are generally ineffective. Liposome-mediated delivery of antibiotics to MAC-infected tissues in vivo can enhance the efficacy of the drugs (N.

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A mycobacterial DNA probe (designated X) was recently developed to help identify Mycobacterium avium complex (MAC) isolates that are nonreactive with probes specific for M. avium or Mycobacterium intracellulare. The prevalence of X probe-positive mycobacteria in clinical specimens and their role in causing disease is unknown.

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The intracellular activities of clarithromycin and erythromycin, alone and in combination with other antimicrobial agents, were tested against Mycobacterium avium complex (MAC) strains inside mouse J774 cells and inside alveolar macrophages obtained from human immunodeficiency type 1-infected individuals. Clarithromycin alone had greater intracellular activity than erythromycin alone, and drug combinations that included clarithromycin were usually more active than combinations that included erythromycin.

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This study sought to better characterize the natural history of AIDS-associated disseminated Mycobacterium avium complex (MAC) infection. Towards that end two retrospective studies were done: a case-control survival study and a MAC respiratory colonization study. Among 137 consecutive patients who had a sterile body site cultured for mycobacteria within 3 months of their first AIDS-defining episode of Pneumocystis carinii pneumonia, median survival was significantly shorter in those with disseminated MAC infection (107 days; 95% confidence interval [CI] 55-179) than those with negative cultures (275 days; 95% CI 230-318; P less than .

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