Informing air-carbon ablation modeling with theoretical calculations of atomic oxygen and nitrogen interacting with carbon surfaces.

To understand the gas-surface chemistry above the thermal protection system of a hypersonic vehicle, it is necessary to map out the kinetics of key elementary reaction steps. In this work, extensive periodic density functional theory (DFT) calculations are performed to elucidate the interaction of atomic oxygen and nitrogen with both the basal plane and edge sites of highly oriented pyrolytic graphite (HOPG). Reaction energies and barriers are determined for adsorption, desorption, diffusion, recombination, and several reactions. These DFT results are compared with the most recent finite-rate model for air-carbon ablation. Our DFT results corroborated some of the parameters used in the model but suggest that further refinement may be necessary for others. The calculations reported here will help to establish a predictive kinetic model for the complex reaction network present under hypersonic flight conditions.

Right hip gonococcal septic arthritis treatment with successful transition to oral fluoroquinolone.

We present a case of gonococcal septic arthritis of the right hip diagnosed via synovial fluid cultures. Antimicrobial susceptibility testing of the synovial fluid demonstrated susceptibility to tetracycline, ciprofloxacin, cefixime and ceftriaxone. Our patient was initially treated with ceftriaxone and was successfully de-escalated to oral levofloxacin to complete the treatment. This case is interesting given the rarity of disseminated gonococcal infections in the 21st century and that most clinical isolates of Neisseria gonorrhoeae are increasingly resistant to fluoroquinolones.

A Case Report of Melioidotic Prostatic Abscess in a Traveler.

A 48-year-old man who had returned from Panama 5 weeks prior presented with fever, dysuria, hematuria, flank pain, and suprapubic pain and was found to have a prostatic abscess. Abscess fluid obtained during transurethral drainage grew Burkholderia pseudomallei. Blood cultures remained negative, and imaging did not show any other visceral abscess. This presentation of primary prostatic melioidosis is extremely rare in this region.

An Eye-Opening Presentation of Syphilis.

Syphilis has been called "the great masquerader." In this case report, we present a case of an HIV-negative patient with left eye redness and decreased vision. Syphilitic anterior uveitis as a complication of neurosyphilis was subsequently diagnosed and the patient showed marked improvement with treatment.

Bartonella Endocarditis: A Missed Diagnosis in Medical Practice.

Here, we present the case of a 52-year-old patient who presented with fever, chills, and weight loss. Further workup revealed Bartonella endocarditis of the aortic valve. After six weeks of antibiotics, a follow-up transthoracic echocardiogram showed a decrease in the size of vegetation. Serologic testing based on epidemiologic history should be obtained for the workup of blood culture-negative endocarditis.

Miliary Histoplasmosis in a Renal Transplant Patient.

Solid organ transplant (SOT) recipients are at increased risk of opportunistic infections due to significant T-cell immune dysfunction. The incidence of clinical disseminated histoplasmosis is rare, and its variable clinical presentation and response to therapy make it challenging to treat with resultant high mortality. A high index of clinical suspicion is necessary, especially in non-endemic areas. We report our clinical experience treating a 63-year-old renal transplant patient on immunosuppressive therapy with late-onset acute miliary histoplasmosis initiated on liposomal amphotericin B (L-AmB).

Thalamic bacterial abscess presenting with hemiparesis and expressive aphasia.

Brain abscesses are relative rare in the developing world, with an incidence of 2% of all space occupying lesions. Deep-seated abscesses such as thalamic and basal ganglia abscesses are much rarer than abscesses in other locations of the brain, comprising 1.3-6% of all brain abscesses. These abscesses may present with hemiparesis, and subcortical aphasia has only been reported in a few cases throughout the literature. Here we present and discuss a case of thalamic brain abscess caused by S. anginosus that presented with subcortical aphasia.

An unusual case of acute transverse myelitis caused by HSV-1 infection.

Transverse myelitis is a neurological disorder of the spinal cord that can have a variety of etiologies. Herpes simplex virus (HSV) infection has been described as one of the causes, most commonly HSV type 2. We report here a case of an 18 year old male who presented with weakness that started in his upper extremities and rapidly evolved to quadriplegia. Magnetic resonance imaging of spine was consistent with transverse myelitis. HSV type 1 PCR testing on cerebrospinal fluid (CSF) was positive. He was started on acyclovir and steroids, but despite therapy, patient did not recover motor function.

HTLV-1 and HIV-1 co-infection: A case report and review of the literature.

HTLV type 1 and 2 are both involved in actively spreading epidemics, affecting over 15 million people worldwide. HTLV-1 has been described as the more clinically significant one, being associated with diseases such as adult T-cell leukemia and tropical spastic paraparesis. We report here a case of tropical spastic paraparesis in an HIV-positive patient who did not report any history of travel or residence in an HTLV endemic area. A 57 year old African-American male was admitted to the hospital due to bilateral upper and lower extremity weakness associated with stiffness. He had recently been diagnosed with HIV. His physical examination showed mild to moderate decreased motor strength, in both upper extremities and marked loss in both lower extremities. This was associated with hyperreflexia and clonus. Sensory function was intact. He looked cachectic and had several psoriatic plaques on both lower and upper extremities. Laboratory work-up showed a CD4 count decreased to 94 cells/mm(3) and a HIV viral load of 273,000 copies/mL. Based on serum positivity for HTLV type 1 and the patient's clinical presentation suggestive of upper and lower motor neuron dysfunction, the diagnosis of tropical spastic paraparesis was made. HTLV and HIV share the same routes of transmission and the same tropism for T-lymphocytes. Co-infection occurs probably more frequently than we are aware, since testing for HTLV is not routinely performed in outpatient HIV clinics.

Austrian's triad complicated by suppurative pericarditis and cardiac tamponade: a case report and review of the literature.

Austrian's triad is a rare complication of disseminated Streptococcus pneumoniae infection consisting of pneumonia, meningitis, and endocarditis. We report what we believe to be the first case of Austrian's triad further complicated by purulent pericarditis and cardiac tamponade, and review the relevant literature.

Hepatitis B vaccine: a seven-year study of adherence to the immunization guidelines and efficacy in HIV-1-positive adults.

BACKGROUND: Vaccination against hepatitis B virus (HBV) has been recommended for all high-risk adults since 1982. Since the advent of highly active antiretroviral therapy, few studies have examined adherence to the Infectious Diseases Society of America (IDSA) and Advisory Committee on Immunization Practices (ACIP) guidelines for hepatitis B vaccination in persons infected with HIV. METHODS: This was a seven-year retrospective, cross-sectional analysis of HBV vaccination practices in HIV-1-positive adults treated in an urban ambulatory care center. Compliance with screening, hepatitis B vaccination recommendations, and response to vaccination were assessed. RESULTS: Of the 1601 charts reviewed, 717 persons were eligible for vaccination against hepatitis B. Of these patients, 503 received at least one dose of vaccine, but only 356 patients completed the three-dose series. Vaccine response was associated with CD4 count (p=0.006) and viral load (p=0.001) at the time of the first dose. However, development of hepatitis B surface antibody was seen at all CD4 counts and viral loads. The multivariate analysis showed only the HIV viral load was predictive of immunologic response. Twenty of the vaccine-eligible patients who did not receive vaccination were infected with HBV during the study period. No vaccinated persons contracted hepatitis B. CONCLUSION: Failure to implement these guidelines represents a missed opportunity to prevent disease. In our study, HIV viral load was better than CD4 count as a predictor of response to the HBV vaccination. However, neither low CD4 count nor high HIV viral load should be used as justification to delay vaccination of high-risk persons.

Outbreak of healthcare-associated infection and colonization with multidrug-resistant Salmonella enterica serovar Senftenberg in Florida.

BACKGROUND: In July 1999, a rare strain of multidrug-resistant Salmonella enterica serovar Senftenberg was isolated from the sputum of a trauma patient. Over a 6-year period (1999-2005) in northeast Florida, this Salmonella serovar spread to 66 other patients in 16 different healthcare facilities as a result of frequent transfers of patients among institutions. To our knowledge, this is the first outbreak of healthcare-associated infection and colonization with a fluoroquinolone-resistant strain of S. Senftenberg in the United States. OBJECTIVES: To investigate an outbreak of infection and colonization with an unusual strain of S. Senftenberg and assist with infection control measures. DESIGN: A case series, outbreak investigation, and microbiological study of all samples positive for S. Senftenberg on culture. SETTING: Cases of S. Senftenberg infection and colonization occurred in hospitals and long-term care facilities in 2 counties in northeast Florida. RESULTS: The affected patients were mostly elderly persons with multiple medical conditions. They were frequently transferred between healthcare facilities. This Salmonella serovar was capable of long-term colonization of chronically ill patients. All S. Senftenberg isolates tested shared a similar pulsed-field gel electrophoresis (PFGE) pattern. CONCLUSION: A prolonged outbreak of infection and colonization with multidrug-resistant S. Senftenberg was identified in several healthcare facilities throughout the Jacksonville, Florida, area and became established when infection control measures failed. The bacterial agent was capable of long-term colonization in chronically ill patients. Because the dispersal pattern of this strain suggested a breakdown of infection control practices, a multipronged intervention approach was undertaken that included intense education of personnel in the different institutions, interinstitutional cooperation, and transfer paperwork notification.

Directly observed therapy for the treatment of people with human immunodeficiency virus infection: a work in progress.

The principle of directly observed therapy (DOT) has its roots in the treatment of tuberculosis (TB), for which DOT programs have improved cure rates in hard-to-reach populations. Human immunodeficiency virus (HIV) and TB affect similar populations, and there are concerns about both regarding the development of drug resistance associated with poor adherence to therapy. Accordingly, DOT may benefit certain HIV-infected people who have difficulty adhering to highly active antiretroviral therapy. However, important differences exist in the treatment of these diseases that raise questions about how DOT can be adapted to HIV therapy. DOT for management of HIV infection has been effective among prisoners and in pilot programs in Haiti, Rhode Island, and Florida. Although DOT can successfully treat HIV infection in marginalized populations in the short term, a multitude of questions remain. This review provides an account of the preliminary development of DOT programs for the treatment of HIV-infected individuals.