Publications by authors named "Michael Landrum"
We conducted a randomized, double-blind, placebo-controlled dose-escalation study in healthy adults to evaluate the safety and immunogenicity of recombinant Staphylococcus aureus candidate vaccine antigens, recombinant α-toxoid (rAT) and a sub-unit of Panton-Valentine leukocidin (rLukS-PV). 176 subjects were enrolled and randomized within 1 of 11 treatment cohorts: monovalent rAT or rLukS-PV dosages of 10, 25, 50, and 100 μg; bivalent rAT:rLukS dosages of 10:10, 25:25, and 50:50 μg; and alum or saline placebo. All subjects were assessed at Days 0, 7, 14, 28, and 84.
View Article and Find Full Text PDFBackground: In outbreak settings, mass vaccination strategies could maximize health protection of military personnel. Self-administration of live attenuated influenza vaccine (LAIV) may be a means to vaccinate large numbers of people and achieve deployment readiness while sparing the use of human resources.
Methods: A phase IV, open-label, randomized controlled trial evaluating the immunogenicity and acceptance of self-administered (SA) LAIV was conducted from 2012 to 2014.
Importance: In individuals with human immunodeficiency virus 1 (HIV-1) infection who are receiving antiretroviral therapy (ART), factors that promote full immune recovery are not well characterized.
Objective: To investigate the influence of the timing of ART relative to HIV-1 infection on normalization of CD4+ T-cell counts, AIDS risk, and immune function.
Design, Setting, And Participants: Participants in the observational US Military HIV Natural History Study with documented estimated dates of seroconversion (EDS) who achieved virologic suppression with ART were evaluated.
Background: Delayed-type hypersensitivity (DTH) test responsiveness is associated with HIV disease progression; however it is unknown whether other immune markers, such as hepatitis B virus (HBV) vaccine seroresponse, also predict HIV outcomes.
Methods: Eligible participants received HBV vaccine after HIV diagnosis, had non-anergic DTH testing at the time of last HBV vaccination, and available post-vaccine HBV antibody responses. The risk of progression to AIDS or death from the time of last HBV vaccination was evaluated.
HIV outcomes in Hepatitis B virus coinfected individuals on HAART.
J Acquir Immune Defic Syndr
June 2014
Background: Understanding the impact of hepatitis B virus (HBV) coinfection on HIV outcomes in the highly active antiretroviral therapy (HAART) era continues to be a critical priority given the high prevalence of coinfection and the potential for impaired immunologic, virologic, and clinical recovery.
Methods: Participants from the US Military HIV Natural History Study with an HIV diagnosis on HAART and serologically confirmed HBV infection status at HAART initiation (HI) were classified into 4 HBV infection (HB) groups. HIV virologic, immunologic, and clinical outcomes were evaluated by HB status.
Background: Prior studies have suggested that HAART initiation may vary by race/ethnicity. Utilizing the U.S.
View Article and Find Full Text PDFBackground: Staphylococcus aureus [methicillin-resistant and methicillin-susceptible (MRSA/MSSA)] is a leading cause of infections in military personnel, but there are limited data regarding baseline colonization of individuals while deployed. We conducted a pilot study to screen non-deployed and deployed healthy military service members for MRSA/MSSA colonization at various anatomic sites and assessed isolates for molecular differences.
Methods: Colonization point-prevalence of 101 military personnel in the US and 100 in Afghanistan was determined by swabbing 7 anatomic sites.
Background: Methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) Staphylococcus aureus colonization is associated with increased rates of infection. Rapid and reliable detection methods are needed to identify colonization of nares and extra-nare sites, particularly given recent reports of oropharynx-only colonization. Detection methods for MRSA/MSSA colonization include culture, PCR, and novel methods such as PCR/electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS).
View Article and Find Full Text PDFBackground: The US military has seen steady increases in multidrug-resistant (MDR) gram-negative bacteria (GNB) infections in casualties from Iraq and Afghanistan. This study evaluates the prevalence of MDR GNB colonization in US military personnel.
Methods: GNB colonization surveillance of healthy, asymptomatic military personnel (101 in the US and 100 in Afghanistan) was performed by swabbing 7 anatomical sites.
Background: Major advances in combat casualty care have led to increased survival of patients with complex extremity trauma. Invasive fungal wound infections (IFIs) are an uncommon, but increasingly recognized, complication following trauma that require greater understanding of risk factors and clinical findings to reduce morbidity.
Methods: The patient population includes US military personnel injured during combat from June 2009 through December 2010.
Purpose: To evaluate the impact of enzyme-inducing antiepileptic drugs (EI-AEDs) on serum antiretroviral (ARV) levels in patients with HIV.
Methods: Data from the U.S.
Context: Rates of hospital-onset methicillin-resistant Staphylococcus aureus (MRSA) infections are reported as decreasing, but recent rates of community-onset S. aureus infections are less known.
Objectives: To characterize the overall and annual incidence rates of community-onset and hospital-onset S.
Background: The well-described biologic and epidemiologic associations of syphilis and HIV are particularly relevant to the military, as service members are young and at risk for sexually transmitted infections. We therefore used the results of serial serologic testing to determine the prevalence, incidence, and risk factors for incident syphilis in a cohort of HIV-infected Department of Defense beneficiaries.
Methods: Participants with a positive nontreponemal test at HIV diagnosis that was confirmed on treponemal testing were categorized as prevalent cases, and participants with an initial negative nontreponemal test who subsequently developed a confirmed positive nontreponemal test were categorized as incident cases.
Background: Delayed-type hypersensitivity (DTH) testing, an in vivo assessment of cell-mediated immunity, is a predictor of HIV disease progression beyond CD4 cell count. We investigated whether preserved DTH responsiveness was characteristic of HIV controllers compared to non-controllers and individuals on suppressive HAART.
Findings: DTH testing consisted of ≥ 3 recall antigens applied approximately every 6 months.
Background: Whether seroresponse to a vaccine such as hepatitis B virus (HBV) vaccine can provide a measure of the functional immune status of HIV-infected persons is unknown.This study evaluated the relationship between HBV vaccine seroresponses and progression to clinical AIDS or death.
Methods And Findings: From a large HIV cohort, we evaluated those who received HBV vaccine only after HIV diagnosis and had anti-HBs determination 1-12 months after the last vaccine dose.
To determine whether hepatitis E virus (HEV) is a cause of hepatitis among HIV-infected persons, we evaluated 1985-2009 data for US military beneficiaries. Evidence of acute or prior HEV infection was detected for 7 (4%) and 5 (3%) of 194 HIV-infected persons, respectively. HEV might be a cause of acute hepatitis among HIV-infected persons.
View Article and Find Full Text PDFObjectives: To investigate the epidemiology and risk factors of gonorrhoea (GC) or chlamydia (CT) coinfection in an HIV-positive US military cohort, focusing on the time after participants' knowledge of HIV diagnosis.
Methods: The authors analysed data from 4461 participants enrolled in the U.S.
Background: Understanding the impact of hepatitis B virus (HBV) in human immunodeficiency virus (HIV) coinfection has been limited by heterogeneity of HIV disease. We evaluated HBV coinfection and HIV-related disease progression in a cohort of HIV seroconverters.
Methods: Participants with HIV diagnosis seroconversion window of ≤ 3 years and serologically confirmed HBV infection (HB) status were classified at baseline into 4 HB groups.
Changes in serologic status in human immunodeficiency virus (HIV)/hepatitis B virus (HBV) co-infected individuals with either isolated anti-HBc or resolved HBV infection have been reported, but the frequency of clinically meaningful long-term serologic changes is not well-defined. This study therefore, examined longitudinal serologic status for hepatitis B surface antigen (HBsAg)-negative HIV/HBV co-infected participants in a large cohort. Among 5,222 cohort participants, 347 (7%) were initially isolated anti-HBc positive, and 1,073 (21%) had resolved HBV infection (concurrently reactive for anti-HBc and anti-HBs).
View Article and Find Full Text PDFBackground: The impact of viral load (VL) decay and cumulative VL on CD4 recovery and AIDS after highly-active antiretroviral therapy (HAART) is unknown.
Methods And Findings: Three virologic kinetic parameters (first year and overall exponential VL decay constants, and first year VL slope) and cumulative VL during HAART were estimated for 2,278 patients who initiated HAART in the U.S.
Background: Vaccination provides long-term immunity to hepatitis A virus (HAV) among the general population, but there are no such data regarding vaccine durability among human immunodeficiency virus (HIV)-infected adults.
Methods: We retrospectively studied HIV-infected adults who had received 2 doses of HAV vaccine. We analyzed blood specimens taken at 1 year, 3 years, and, when available, 6-10 years postvaccination.
Background: To evaluate the efficacy of highly-active antiretroviral therapy (HAART) in individuals taking cytochrome P450 enzyme-inducing antiepileptics (EI-EADs), we evaluated the virologic response to HAART with or without concurrent antiepileptic use.
Methods: Participants in the US Military HIV Natural History Study were included if taking HAART for ≥6 months with concurrent use of EI-AEDs phenytoin, carbamazepine, or phenobarbital for ≥28 days. Virologic outcomes were compared to HAART-treated participants taking AEDs that are not CYP450 enzyme-inducing (NEI-AED group) as well as to a matched group of individuals not taking AEDs (non-AED group).
Background: The relationship between CD4 T-cell counts determined soon after seroconversion with HIV-1 (baseline CD4), nadir CD4, and CD4 levels attained during highly active antiretroviral therapy (HAART) is unknown.
Methods: Longitudinal, including baseline (at or soon after HIV diagnosis), intermediate (nadir), and distal (post-HAART) CD4 T-cell counts were assessed in 1085 seroconverting subjects who achieved viral load suppression from a large well-characterized cohort. The association of baseline with post-HAART CD4 T-cell count was determined after adjustment for other relevant covariates.