T2 Magnetic Resonance for Fungal Diagnosis.

Rapid diagnostic methods for fungal infections are long awaited and are expected to improve outcomes through early initiation of targeted antifungal therapy. T2Candida panel is a novel qualitative diagnostic platform that was recently approved by the US Food and Drug Administration (FDA) for diagnosis of candidemia with a mean time to species identification of less than 5 h. T2Candida panel is performed on the fully automated T2Dx instrument in whole blood K2EDTA specimens and is able to detect 5 Candida spp., namely Candida albicans, Candida tropicalis, Candida parapsilosis, Candida krusei, and Candida glabrata. By combining magnetic resonance with molecular diagnostics, T2Candida panel amplifies DNA and detects the amplified product by amplicon-induced agglomeration of supermagnetic particles and T2 Magnetic Resonance (T2MR) measurement. Here we describe the materials and methods needed to diagnose candidemia with the T2Candida panel.

Evaluation of Performance Characteristics of the Aptima HIV-1 Quant Dx Assay for Detection and Quantitation of Human Immunodeficiency Virus Type 1 in Plasma and Cervicovaginal Lavage Samples.

Quantification of HIV-1 RNA has become the standard of care in the clinical management of HIV-1-infected individuals. The objective of this study was to evaluate performance characteristics and relative workflow of the Aptima HIV-1 Quant Dx assay in comparison with the Abbott RealTime HIV-1 assay using plasma and cervicovaginal lavage (CVL) specimens. Assay performance was evaluated by using an AcroMetrix HIV-1 panel, AcroMetrix positive controls, Qnostics and SeraCare HIV-1 evaluation panels, 208 clinical plasma samples, and 205 matched CVL specimens on the Panther and m2000 platforms. The Aptima assay demonstrated good linearity over the quantification range tested (2 to 5 log10copies/ml), and there was strong linear correlation between the assays (R(2)= 0.99), with a comparable coefficient of variance of <5.5%. For the plasma samples, Deming regression analyses and Bland-Altman plots showed excellent agreement between the assays, with an interassay concordance of 91.35% (kappa = 0.75; 95% confidence interval [CI], 0.65 to 0.85), and on average, the viral loads determined by the Aptima assay were 0.21 log10copies/ml higher than those determined by the RealTime assay. The assays differed in their sensitivity for quantifying HIV-1 RNA loads in CVL samples, with the Aptima and RealTime assays detecting 30% and 20%, respectively. Aptima had fewer invalid results, and on average, the viral loads in CVL samples quantified by the Aptima assay were 0.072 log10copies/ml higher than those of the RealTime assay. Our results demonstrate that the Aptima assay is sensitive and accurate in quantifying viral loads in both plasma and CVL specimens and that the fully automated Panther system has all the necessary features suitable for clinical laboratories demanding high-throughput sample processing.

Pharmacokinetics of First-Line Antituberculosis Drugs Using WHO Revised Dosage in Children With Tuberculosis With and Without HIV Coinfection.

BACKGROUND: Pharmacokinetic data on the first-line antituberculosis drugs using the World Health Organization (WHO) revised dosages for children are limited. We investigated the pharmacokinetics of these drugs in children who were mostly treated with revised dosages. METHODS: Children with tuberculosis on first-line therapy for at least 4 weeks had blood samples collected at predose, 1, 2, 4, and 8 hours postdose. Drug concentrations were determined by validated liquid chromatography mass spectrometry methods, and pharmacokinetic parameters were calculated using noncompartmental analysis. Factors associated with plasma peak concentration (Cmax) and the area under the time-concentration curve 0-8 hours (AUC0-8h) of each drug was examined using univariate and multivariate analysis. RESULTS: Of the 62 children, 32 (51.6%) were male, 29 (46.8%) were younger than 5 years old, and 28 (45.2%) had human immunodeficiency virus (HIV) coinfection. Three patients had undetectable pyrazinamide and ethambutol concentrations. The median (interquartile range) AUC0-8h for isoniazid was 17.7 (10.2-23.4) µg·h mL-1, rifampin was 26.0 (15.3-36.1) µg·h mL-1, pyrazinamide was 144.6 (111.5-201.2) µg·h mL-1, and ethambutol was 6.7 (3.8-10.4) µg·h mL-1. Of the children who received recommended weight-band dosages, 44/51 (86.3%), 46/56 (82.1%), 27/56 (48.2%), and 21/51 (41.2%) achieved target Cmax for isoniazid, pyrazinamide, ethambutol, and rifampin, respectively. In multivariate analysis, age, sex, HIV coinfection status, and drug dosage in milligrams per kilogram were associated with the drugs' plasma drug Cmax or AUC0-8h. CONCLUSIONS: The revised dosages appeared to be adequate for isoniazid and pyrazinamide, but not for rifampin or ethambutol in this population. Higher dosages of rifampin and ethambutol than currently recommended may be required in most children.

Factors associated with variability in rifampin plasma pharmacokinetics and the relationship between rifampin concentrations and induction of efavirenz clearance.

STUDY OBJECTIVES: To identify factors associated with variability in rifampin plasma pharmacokinetics and explore the relationship between rifampin pharmacokinetics and change in efavirenz plasma pharmacokinetics with rifampin coadministration. METHODS: In this randomized, cross-over study, 12 healthy volunteers received either efavirenz 600 mg/day or efavirenz 600 mg with rifampin 600 mg/day for 8 days. After a washout period of at least 2 weeks, subjects crossed over to the alternate 8-day regimen. Samples were obtained for pharmacokinetic assessment on day 8 of each study cycle. Drugs concentrations were determined by a validated high-performance liquid chromatography. Pharmacokinetic parameters were calculated using noncompartmental analysis. Multivariate analysis was used to examine factors associated with rifampin pharmacokinetics. Spearman correlation analysis was used to investigate relationship between rifampin pharmacokinetics and change in efavirenz plasma pharmacokinetics with rifampin coadministration. MEASUREMENTS AND MAIN RESULTS: Of 11 evaluable subjects, the median interquartile range, rifampin peak concentration (Cmax) , area under the concentration-time curve (AUC0-24 hour ), and weight-normalized clearance were 8.9 (7.3-13.8) µg/ml, 48.8 (29.6-67.4) µg·h/ml, and 0.19 (0.11-0.29) L/h/kg, respectively. Solute carrier organic anion transporter family member 1B1 (SLCO1B1) c.388A→G and SLCO1B1 c.463C→A polymorphisms jointly had significant effect on rifampin Cmax (R(2)  = 0.75). Male sex and SLCO1B1 c.463C→A polymorphism together influenced rifampin AUC0-24 hour (R(2)  = 0.52) and weight-normalized clearance (R(2)  = 0.65). All four volunteers with rifampin Cmax less than 8 µg/ml (lower end of the normal range) had c.463CA genotype. Rifampin Cmax and AUC0-24 hour had no significant relationship with the efavirenz AUC0-24 hour ratio or weight-normalized clearance ratio in the presence versus absence of rifampin (p>0.05). CONCLUSIONS: Men with the SLCO1B1c.463CA genotype are at increased risk of lower rifampin plasma exposure. However, plasma rifampin concentrations did not correlate with the extent of induction of efavirenz clearance by rifampin during coadministration.

Persistent genital tract HIV-1 RNA shedding after change in treatment regimens in antiretroviral-experienced women with detectable plasma viral load.

OBJECTIVE: To longitudinally assess the association between plasma viral load (PVL) and genital tract human immunodeficiency virus (GT HIV) RNA among HIV-1 infected women changing highly active antiretroviral therapy (HAART) because of detectable PVL on current treatment. METHODS: Women were eligible for the study if they had detectable PVL (defined as two consecutive samples with PVL>1000 copies/mL) and intended to change their current HAART regimen at the time of enrollment. Paired plasma and GT HIV-1 RNA were measured prospectively over 3 years. Longitudinal analyses examined rates of GT HIV-1 RNA shedding and the association with PVL. RESULTS: Sixteen women were followed for a median of 11 visits contributing a total of 205 study visits. At study enrollment, all had detectable PVL and 69% had detectable GT HIV-1 RNA. Half of the women changed to a new HAART regimen with ≥3 active antiretroviral drugs. The probability of having detectable PVL ≥30 days after changing HAART was 0.56 (95% CI: 0.37 to 0.74). Fourteen women (88%) had detectable PVL on a follow-up visit ≥30 or 60 days after changing HAART; and 12 women (75%) had detectable GT HIV-1 RNA on a follow-up visit ≥30 or 60 days after changing HAART. When PVL was undetectable, GT shedding occurred at 11% of visits, and when PVL was detectable, GT shedding occurred at 47% of visits. CONCLUSIONS: Some treatment-experienced HIV-infected women continue to have detectable virus in both the plasma and GT following a change in HAART, highlighting the difficulty of viral suppression in this patient population.

Genital tract HIV-1 RNA shedding among women with below detectable plasma viral load.

OBJECTIVE: Few studies have assessed longitudinal genital tract HIV-1 shedding. We determined patterns of genital tract HIV-1 RNA shedding over time among women with suppressed plasma viral load (PVL) on antiretroviral treatment. METHODS: Paired plasma and genital tract HIV-1 RNA were measured every 4 weeks. Participants were classified as persistent, intermittent, or nonshedders. Longitudinal analysis examined rates of genital tract shedding and the association with PVL, CD4 cell count, and genital tract infections. Markov transition models were used to describe the dynamics of HIV-1 RNA in plasma and genital tract using visit-to-visit transitions from and to detectable and undetectable PVL or genital tract HIV-1 RNA. RESULTS: Fifty-nine women contributed 582 study visits of whom 95 and 98% had below-detectable PVL and genital tract viral load, respectively, at baseline. Thirty-two of 59 women (54%) had detectable HIV-1 RNA at least once in the genital tract. Twenty-two of 59 (37%) women had detectable genital tract HIV-1 RNA during a study visit when PVL was undetectable; 6.8% of the women were persistent shedders, 31% were intermittent shedders, and 45.8% were nonshedders. Sampling three subcompartments increased detection of HIV-1 genital tract viral load compared to sampling a single subcompartment. Overall, genital tract HIV-1 RNA shedding in any subcompartment occurred at about 13% of visits. Shedding in at least one of the three subcompartments occurred at 9% of visits when PVL was undetectable (95% confidence interval 6-14%). CONCLUSION: Women with below-detectable PVL may have less risk of HIV sexual transmission on a population level, but may continue to be infectious on an individual level.

Detection of fastidious vaginal bacteria in women with HIV infection and bacterial vaginosis.

BACKGROUND: Fastidious bacteria have been associated with bacterial vaginosis (BV) using PCR methods. We assessed the prevalence of these bacteria in HIV-1 infected women and their relationship with vaginal pH and shedding of HIV-1 RNA. METHODS: 64 cervicovaginal lavage (CVL) samples were collected from 51 women. Vaginal microbiota were characterized using 8 bacterium-specific quantitative PCR assays. RESULTS: Women with the fastidious bacteria Bacterial Vaginosis Associated Bacterium (BVAB) 1, 2, and 3 showed a trend to increased HIV-1 shedding (OR 2.59-3.07, P = .14-.17). Absence of Lactobacillus crispatus (P < .005) and presence of BVAB2 (P < .001) were associated with elevated vaginal pH. BVAB1, 2, and 3 were highly specific indicators of BV in HIV-infected women, with specificities of 89%-93%. CONCLUSIONS: Fastidious bacteria (BVAB 1, 2, and 3) remain specific indicators of BV in HIV-infected women, and BVAB2 may contribute to the elevated vaginal pH that is a hallmark of this syndrome.

Genital tract leukocytes and shedding of genital HIV type 1 RNA.

BACKGROUND: The mechanism of human immunodeficiency virus (HIV) transmission via heterosexual intercourse is unknown. We sought to determine whether the presence of inflammatory cells in the vagina is associated with the presence of genital tract HIV type 1 (HIV-1) RNA. METHODS: Analysis of a longitudinal prospective cohort was performed. Women with HIV-1 infection were assessed with use of paired plasma and cervicovaginal lavage specimens. Viral load measurements were performed using nucleic acid sequence-based amplification. White blood cells found in the genital tract (GT WBCs) were quantified using a hemacytometer. Common lower genital tract infections assessed for association with viral shedding (i.e., genital tract viral load [GTVL]) included bacterial vaginosis, candidiasis, and trichomoniasis. Generalized estimating equations were used to estimate the prevalence and odds of detectable GTVL by GT WBC. The association was examined both in the presence and in the absence of lower genital tract infections. RESULTS: A total of 97 women and 642 visits were included in the analysis. Median duration of follow-up was 30.4 months. Thirty women (31%) had detectable GTVL at any visit. The median CD4 cell count at baseline was 525 cells/muL. Most women were antiretroviral therapy naive at baseline. After adjustment for plasma viral load, the odds of detectable GTVL increased as GT WBC increased, with an odds ratio of 1.36 (95% confidence interval, 1.1-1.7) per 1000-cell increase in GT WBC among women without lower genital tract infections. After adjustment for plasma viral load and lower genital tract infections by incorporating them in a regression model, GT WBC remained significantly associated with GTVL, with an adjusted odds ratio of 1.22 (95% confidence interval, 1.08-1.37). CONCLUSIONS: The presence of GT WBC is associated with an increased risk of detectable GTVL.

Association between paired plasma and cervicovaginal lavage fluid HIV-1 RNA levels during 36 months.

OBJECTIVE: To determine the patterns and predictors of genital tract HIV-1 RNA levels during a 36-month period. METHODS: HIV-1 RNA levels were measured blood in plasma and the genital tract (by cervicovaginal lavage [CVL]) at baseline before highly, active antiretroviral therapy, at 2 and 4 weeks and every 6 months. Viral loads were measured using nucleic acid sequence-based amplification assay with a lower limit of detection of 2.6 log10 copies/mL. RESULTS: Ninety-seven women had a median of 30.4 months' follow-up, with 530 paired PVL and CVL specimens. The strongest predictor of CVL fluid HIV-1 RNA detection was PVL of more than 2.6 log10 copies/mL, with an odds ratio of 13.7 (P < 0.0001). Each log10 unit increase in PVL increased the odds of detecting HIV-1 RNA in CVL fluid by 2.6 folds (P = 0.0002). Cervicovaginal lavage fluid HIV-1 RNA exceeded PVL on 5% of visits. When patients achieved undetectable levels of HIV-1 RNA in both plasma and CVL fluid, rebound of HIV-1 RNA occurred in plasma first or concurrently with CVL fluid HIV-1 RNA. CONCLUSIONS: Plasma viral load is the strongest predictor of CVL fluid HIV-1 RNA detection. Cervicovaginal lavage fluid HIV-1 RNA levels are generally lower than PVL. Plasma viral load is more likely to rebound first or at the same time as CVL fluid viral load.