Albert M. Anderson

Multidrug-Resistant Tuberculosis Drug Susceptibility and Molecular Diagnostic Testing

Abstract:Multidrug-resistant tuberculosis (MDR TB), defined by resistance to the 2 most effective first-line drugs, isoniazid and rifampin, is on the rise globally and is associated with significant morbidity and mortality. Despite the increasing availability of novel rapid diagnostic tools for Mycobacterium tuberculosis (Mtb) drug susceptibility testing, the clinical applicability of these methods is unsettled. In this study, the mechanisms of action and resistance of Mtb to isoniazid and rifampin, and the utility, advantages and limitations of the available Mtb drug susceptibility testing tools are reviewed, with particular emphasis on molecular methods with rapid turnaround including line probe assays, molecular beacon-based real-time polymerase chain reaction and pyrosequencing. The authors conclude that neither rapid molecular drug testing nor phenotypic methods are perfect in predicting Mtb drug susceptibility and therefore must be interpreted within the clinical context of each patient.

Fanconi Syndrome Accompanied by Renal Function Decline with Tenofovir Disoproxil Fumarate: A Prospective, Case-Control Study of Predictors and Resolution in HIV-Infected Patients

Objective The predictors of Fanconi syndrome (FS) accompanied by renal function decline with use of the antiretroviral tenofovir disoproxil fumarate (TDF) have not been assessed. In addition, the natural history of renal recovery from FS after TDF discontinuation is not well-described. Design We prospectively enrolled HIV-infected patients receiving TDF with newly identified FS (defined as at least two markers of proximal tubulopathy and either a >25% decline in creatinine clearance (CrCl) from pre-TDF values or a CrCl <60 mL/min in those without a known pre-TDF CrCl) in a multicenter observational study. These case participants were matched 1∶2 to controls; characteristics between the two groups were compared. Case participants with known pre-TDF CrCl values were then followed over 48 weeks to assess renal recovery. Results Nineteen cases and 37 controls were enrolled. In multivariable analysis, previous or concurrent use of lopinavir/ritonavir [OR 16.37, 95% CI (2.28, 117.68); P = 0.006] and reduced creatinine clearance prior to initiation of TDF [OR 1.44 for every 5 mL/min reduction, 95% CI (1.09, 1.92); P = 0.012; OR 19.77 for pre-TDF CrCl lower than 83 mL/min, 95% CI (2.24, 174.67); P = 0.007] were significantly associated with FS. Of the 14 cases followed for resolution, 7 (50%) achieved at least partial resolution (defined as recovering CrCl >70% of pre-TDF values) although most participants had full normalization of proximal tubulopathy markers within two months of TDF discontinuation. Conclusions FS, defined by specific CrCl decreases and markers of tubulopathy, is more likely in those who have received or are currently receiving concomitant lopinavir/ritonavir or who had lower CrCl prior to TDF initiation. Half of those with protocol-defined FS had CrCl recover to near pre-TDF values during the first year after TDF discontinuation.

Histoplasmosis in Patients With Human Immunodeficiency Virus/Acquired Immunodeficiency Syndrome (HIV/AIDS): Multicenter Study of Outcomes and Factors Associated With Relapse

AbstractAlthough discontinuation of suppressive antifungal therapy for acquired immunodeficiency syndrome (AIDS)-associated histoplasmosis is accepted for patients with immunologic recovery, there have been no published studies of this approach in clinical practice, and minimal characterization of individuals who relapse with this disease. We performed a multicenter retrospective cohort study to determine the outcome in AIDS patients following discontinuation of suppressive antifungal therapy for histoplasmosis.Ninety-seven patients were divided into a physician-discontinued suppressive therapy group (PD) (38 patients) and a physician-continued suppressive therapy group (PC) (59 patients). The 2 groups were not statistically different at baseline, but at discontinuation of therapy and at the most recent follow-up there were significant differences in adherence to therapy, human immunodeficiency virus (HIV) RNA, and urinary Histoplasma antigen concentration. There was no relapse or death attributed to histoplasmosis in the PD group compared with 36% relapse (p < 0.0001) and 5% death (p = 0.28) in the PC group. Relapse occurred in 53% of the nonadherent patients but not in the adherent patients (p < 0.0001). Sixty-seven percent of patients with initial central nervous system (CNS) histoplasmosis relapsed compared to 15% of patients without CNS involvement (p = 0.0004), which may be accounted for by nonadherence. In addition, patients with antigenuria above 2.0 ng/mL at 1-year follow-up were 12.82 times (95% confidence interval, 2.91–55.56) more likely to relapse compared to those with antigenuria below 2.0 ng/mL.Discontinuation of antifungal therapy was safe in adherent patients who completed at least 1 year of antifungal treatment, and had CD4 counts >150 cells/mL, HIV RNA <400 c/mL, Histoplasma antigenuria <2 ng/mL (equivalent to <4.0 units in second-generation method), and no CNS histoplasmosis.

Review ArticleMultidrug-Resistant Tuberculosis Drug Susceptibility and Molecular Diagnostic Testing

Abstract:Multidrug-resistant tuberculosis (MDR TB), defined by resistance to the 2 most effective first-line drugs, isoniazid and rifampin, is on the rise globally and is associated with significant morbidity and mortality. Despite the increasing availability of novel rapid diagnostic tools for Mycobacterium tuberculosis (Mtb) drug susceptibility testing, the clinical applicability of these methods is unsettled. In this study, the mechanisms of action and resistance of Mtb to isoniazid and rifampin, and the utility, advantages and limitations of the available Mtb drug susceptibility testing tools are reviewed, with particular emphasis on molecular methods with rapid turnaround including line probe assays, molecular beacon-based real-time polymerase chain reaction and pyrosequencing. The authors conclude that neither rapid molecular drug testing nor phenotypic methods are perfect in predicting Mtb drug susceptibility and therefore must be interpreted within the clinical context of each patient.

Plasma and Cerebrospinal Fluid Biomarkers Predict Cerebral Injury in HIV-Infected Individuals on Stable Combination Antiretroviral Therapy.

Objectives:HIV-associated brain injury persists despite combination antiretroviral therapy, but contributing factors remain poorly understood. We postulated that inflammation-associated biomarkers will be associated with cerebral injury on proton magnetic resonance spectroscopy in chronically HIV-infected subjects. Methods:Five biomarkers were measured in 197 HIV-infected subjects: soluble CD14, MCP-1, IP-10, MIP-1&bgr;, and fractalkine. Levels of N-acetyl aspartate (NAA), Choline (Cho), Myoinositol (MI), Glutamate + Glutamine (Glx), and Creatine (Cr) were acquired in the midfrontal cortex (MFC), frontal white matter, and basal ganglia (BG). Predictive models were built through linear regression, and the best models were chosen using the Akaike Information Criterion. Results:Increases in plasma or CSF MCP-1 were associated with lower NAA/Cr in the MFC and BG, whereas metabolite changes in the frontal white matter for NAA/Cr, GlxCr, and Cho/Cr were explained almost exclusively by a single factor, sCD14. Plasma and CSF levels of this factor were also significantly associated with Glx/Cr in MFC and BG. Higher CSF FKN was associated with higher NAA/Cr in BG. Best predictors for higher Cho/Cr in BG and MFC were CSF sCD14 and CSF MIP-1&bgr;. Plasma and CSF IP-10 were only associated with Cho/Cr in MFC. Of the 3 models that simultaneously accounted for both plasma and CSF, there were more associations between CSF biomarkers and magnetic resonance spectroscopy metabolites. Conclusions:Markers of inflammation and immune activation, in particular MCP-1 and sCD14, predominantly reflecting CNS sources, contribute to the persistence of brain injury in a metabolite and region-dependent manner in chronically HIV-infected patients on stable combination antiretroviral therapy.

Warfarin Therapy in the HIV Medical Home Model: Low Rates of Therapeutic Anticoagulation Despite Adherence and Differences in Dosing Based on Specific Antiretrovirals

To determine the indications for, rates of therapeutic anticoagulation during, and complications of warfarin therapy in HIV-infected individuals, in whom long-term anticoagulation is frequently indicated. To identify risk factors for nonoptimal anticoagulation and to determine if warfarin dosing is differentially affected by specific antiretroviral agents. Retrospective study of a dedicated anticoagulation program at one of the largest clinics for HIV-infected individuals in the United States. Seventy-three HIV-infected individuals on warfarin were followed for a total of 911 visits. The rate of therapeutic internation normalized ratio (INR) levels was 34.5% when including only visits at which patients were assessed to be adherent with warfarin. In multivariable analysis, injection drug use at baseline was an independent risk factor for subtherapeutic INR (odds ratio [OR] 2.4, 95% confidence interval [CI] 1.3-4.7, p=0.01). Additionally, warfarin adherence was protective of both subtherapeutic (OR 0.4, 95% CI 0.2-0.6, p<0.0001) and supratherapeutic (OR 0.5, 95% CI 0.3-0.9, p=0.02) INR status. Efavirenz-based antiretroviral regimens were associated with lower weekly warfarin doses (46 mg) to maintain therapeutic INR compared to lopinavir/ritonavir-based regimens (68 mg; p=0.01) and atazanavir/ritonavir-based regimens (71 mg; p=0.007). Consistently therapeutic warfarin therapy is difficult to achieve in HIV-infected individuals, even with a dedicated anticoagulation program. Adherence to warfarin therapy is important but rates of therapeutic INR levels are nonetheless low. Lower warfarin dosing was required for efavirenz compared to two commonly used protease inhibitor-based regimens. Because of these factors, the emergence of new oral anticoagulants is an important development for HIV-infected individuals who require long term anticoagulation therapy.

Human immunodeficiency virus-associated cytomegalovirus infection with multiple small vessel cerebral infarcts in the setting of early immune reconstitution

Cytomegalovirus (CMV) infection is an important cause of neurologic disease in the context of advanced human immunodeficiency virus (HIV) infection and is recognized as a cause of immune reconstitution inflammatory syndrome (IRIS) after initiation of highly active antiretroviral therapy (HAART). Central nervous system vasculitis secondary to CMV has only rarely been described in the context of HIV, despite the established ability of CMV to infect microvascular endothelial cells in the brain. However, we report a case that demonstrates the association between CMV and multiple small vessel cerebral infarct lesions after initiation of HAART.

Prevalence and Correlates of Persistent HIV-1 RNA in Cerebrospinal Fluid During Antiretroviral Therapy.

Background. Neurocognitive disorders remain common among human immunodeficiency virus (HIV)–positive adults, perhaps owing to persistent HIV-1 RNA in cerebrospinal fluid (CSF) during antiretroviral therapy (ART). Methods. Using a single-copy assay, we measured HIV-1 RNA levels in CSF and plasma specimens from 220 HIV-positive adults who were taking suppressive ART. Fifty-five participants were tested twice. Results. HIV-1 RNA was detected in 42.3% of CSF and 65.2% of plasma samples. Correlates of higher CSF HIV-1 RNA levels included higher nadir and current CD4+ T-cell counts, a plasma HIV-1 RNA level of ≥ 1 copy/mL, and a lower central nervous system penetration-effectiveness score (model P < .001). Worse neurocognitive performance was associated with discordance in HIV-1 RNA detection between plasma and CSF, lower overall CSF HIV-1 RNA level, and longer ART duration, among others (model P < .001). In the longitudinal subgroup, CSF HIV-1 RNA persisted in most participants (69%) over 7 months. Conclusions. Low-level HIV-1 RNA in CSF is common during suppressive ART and is associated with low-level HIV-1 RNA in blood, better immune status, and lower ART drug distribution into CSF. The association between HIV-1 RNA discordance and HIV-associated neurocognitive disorder (HAND) may reflect compartmentalization. The relationship between HAND, lower HIV-1 RNA levels in CSF, and lower CD4+ T-cell counts may reflect disturbances in the immune response to HIV-1 in the CNS.

Changes in neurocognition and adherence over six months in HIV-infected individuals with cocaine or heroin dependence.

We sought to examine the course of adherence and cognition in HIV-infected individuals with either cocaine or heroin dependence and investigate independent predictors of cognition change. A prospective study over six months was undertaken in which adherence was measured by monthly electronic pill cap monitoring (Medication Event Monitoring System), while a comprehensive neuropsychological battery resulting in a composite score (NPZ8) was performed at baseline and six months. Multivariable regression models were performed in order to determine independent associations with change in cognition. There were 101 subjects at baseline, of whom 62% were male and 83% were non-Hispanic black. 46.6% of subjects at baseline had completed high school, 36.6% reported active cocaine use during the course of the study, and 0% reported active heroin use during the course of the study. 66 subjects completed the final cognitive assessment at six months. Subjects had markedly impaired cognitive function at baseline (NPZ8 –1.49) which persisted at six months (NPZ8 –1.47) in the group of study completers. There was an average monthly decrease in adherence of –2.91% overall (p = 0.008). In the multivariable model, each of the following variables: baseline cognition (R2 change = 0.121, p = 0.006), cocaine use during the study (R2 change = 0.059, p = 0.046), and monthly adherence change (R2 change = 0.078, p = 0.018) independently contributed to NPZ8 change with an overall R2 change = 0.219 (p = 0.001). This study shows an overall decrease in adherence over time in this population of subjects with a history of drug dependence. Active cocaine use, baseline cognition, and temporal adherence changes independently contributed to changes in cognition. Further study on enhancing adherence, cognition, and limiting drug abuse are warranted in this subgroup of HIV-infected individuals.

Prolonged survival of a patient with AIDS and central nervous system aspergillosis.

In HIV-infected patients, central nervous system (CNS) aspergillosis is rare. Historically, the outcome of such infections has been almost invariably fatal. We report a case involving an AIDS patient with an Aspergillus fumigatus brain abscess who survived for longer than 10 months after surgical drainage and therapy with voriconazole.