Biomedical subjects

Bruce Hanna

Publications and source records attributed to Bruce Hanna.

3 recordsLinked to original sources

PubMed2006

Carbapenem resistance in Klebsiella pneumoniae not detected by automated susceptibility testing.

Detecting beta-lactamase-mediated carbapenem resistance among Klebsiella pneumoniae isolates and other Enterobacteriaceae is an emerging problem. In this study, 15 blaKPC-positive Klebsiella pneumoniae that showed discrepant results for imipenem and meropenem from 4 New York City hospitals were characterized by isoelectric focusing; broth microdilution (BMD); disk diffusion (DD); and MicroScan, Phoenix, Sensititre, VITEK, and VITEK 2 automated systems. All 15 isolates were either intermediate or resistant to imipenem and meropenem by BMD; 1 was susceptible to imipenem by DD. MicroScan and Phoenix reported 1 (6.7%) and 2 (13.3%) isolates, respectively, as imipenem susceptible. VITEK and VITEK 2 reported 10 (67%) and 5 (33%) isolates, respectively, as imipenem susceptible. By Sensititre, 13 (87%) isolates were susceptible to imipenem, and 12 (80%) were susceptible to meropenem. The VITEK 2 Advanced Expert System changed 2 imipenem MIC results from >16 ?g/mL to <2 ?g/mL but kept the interpretation as resistant. The recognition of carbapenem-resistant K. pneumoniae continues to challenge automated susceptibility systems.

Anti-Bacterial Agents↗

PubMed2005

Preclinical and clinical performance of the Efoora test, a rapid test for detection of human immunodeficiency virus-specific antibodies.

Barriers to effective diagnostic testing for human immunodeficiency virus type 1 (HIV-1) infection can be reduced with simple, reliable, and rapid detection methods. Our objective was to determine the accuracy, sensitivity, and specificity of a new rapid, lateral-flow immunochromatographic HIV-1 antibody detection device. Preclinical studies were performed using seroconversion, cross-reaction, and interference panels, archived clinical specimens, and fresh whole blood. In a multicenter, prospective clinical trial, a four-sample matrix of capillary (fingerstick) whole-blood specimens and venous whole blood, plasma, and serum was tested for HIV-1 antibodies with the Efoora HIV rapid test (Efoora Inc., Buffalo Grove, IL) and compared with an enzyme immunoassay (EIA) (Abbott Laboratories) licensed by the Food and Drug Administration. Western blot and nucleic acid test supplemental assays were employed to adjudicate discordant samples. Preclinical testing of seroconversion panels showed that antibodies were often detected earlier by the rapid test than by a reference EIA. No significant interference or cross-reactions were observed. Testing of 4,984 archived specimens yielded a sensitivity of 99.2% and a specificity of 99.7%. A prospective multicenter clinical study with 2,954 adult volunteers demonstrated sensitivity and specificity for the Efoora HIV rapid test of 99.8% (95% confidence interval [CI], 99.3 and 99.98%) and 99.0% (95% CI, 98.5 and 99.4%), respectively. Reactive rapid HIV-1 antibody detection was confirmed in 99.6% of those with a known HIV infection (n = 939), 5.2% of those in the high-risk group (n = 1,003), and 0.1% of those in the low-risk group (n = 1,012). For 21 (0.71%) patients, there was discordance between the results of the rapid test and the confirmatory EIA/Western blot tests. We conclude that the Efoora HIV rapid test is a simple, rapid assay for detection of HIV-1 antibodies, with high sensitivity and specificity compared to a standardized HIV-1 EIA.

HIV Antibodies↗

PubMed2005

Human immunodeficiency virus (HIV) reverse transcriptase activity correlates with HIV RNA load: implications for resource-limited settings.

Measurement of human immunodeficiency virus type 1 (HIV-1) plasma RNA levels using Roche AMPLICOR version 1.5 (HIV RNA) is an integral part of monitoring HIV-infected patients in industrialized countries. These assays are currently unaffordable in resource-limited settings. We investigated a reverse transcriptase (RT) assay as a less expensive alternative for measuring viral burden that quantifies RT enzyme activity in clinical plasma samples. A comparison of RT and HIV RNA assays was performed on 29 paired plasma samples from patients living in the United States and 21 paired plasma samples from patients living in Cameroon. RT levels correlated significantly with plasma HIV RNA viral loads in plasma from U.S. patients (r = 0.898; P < 0.001) and Cameroonian patients, a majority of whom were infected with HIV-1 clade type CRF02_AG (r = 0.669; P < 0.01). Among 32 samples with HIV viral load of >2,000 copies/ml, 97% had detectable RT activity. One Cameroon sample had undetectable RNA viral load but detectable RT activity of 3 fg/ml. The RT assay is a simple and less expensive alternative to the HIV RNA assay. Field studies comparing these assays in resource-limited settings are warranted to assess the practicality and usefulness of this assay for monitoring HIV-infected patients on antiretroviral therapy.

Cohort Studies↗