Jean A. Wiedeman

Detection of Chlamydia pneumoniae DNA in CD3+ Lymphocytes From Healthy Blood Donors and Patients With Coronary Artery Disease

BackgroundChlamydia pneumoniae is an intracellular bacterium responsible for respiratory tract infections. Recent studies have implicated this organism in the pathogenesis of atherosclerosis. Methods and ResultsTo address how the organism is transported from lungs to cardiac vessels, we characterized the cell population within peripheral blood mononuclear cells (PBMCs) that harbor C pneumoniae DNA. Adherent and nonadherent PBMCs from 28 patients with coronary artery disease (CAD) and 19 healthy blood donors were evaluated for the presence of C pneumoniae DNA by touchdown nested polymerase chain reaction (nPCR). Of the 28 patients, 10 (36%) had detectable PCR product in their nonadherent and 3 (10%) in their adherent PBMC population. C pneumoniae–specific PCR results were positive for 5 of 19 (26%) healthy blood donors. PCR positivity was detected only in the nonadherent cell population among this group of individuals. Fractionation of nonadherent PBMCs identified C pneumoniae–specific PCR signal among the CD3+ T-cell population exclusively. Of the 18 PCR-positive subjects (13 patients and 5 healthy control subjects), 67% (8 patients and 4 healthy blood donors) tested positive for C pneumoniae–specific IgG serology. Interestingly, 2 patients became PCR negative on a repeated blood draw 5 months after initial detection of C pneumoniae DNA despite retaining C pneumoniae–specific antibodies. ConclusionsOur results demonstrate marginally significant prevalence of C pneumoniae DNA in patients with CAD compared with healthy subjects (P =0.082). In contrast, the prevalence of IgG seropositivity among the 2 groups did not reach statistical significance (P =0.306). We also provide unequivocal evidence for the presence of C pneumoniae DNA predominantly among the circulating CD3+ T-cell population.

A combination of secondhand cigarette smoke and Chlamydia pneumoniae accelerates atherosclerosis

OBJECTIVE Secondhand smoke (SS) induces chronic infection of endothelial cells by Chlamydia pneumoniae (Cpn) in vitro. We investigated the in vivo effect on atherosclerosis following exposure to SS and infection with Cpn both independently and in combination in ApoE-/- mice. METHODS AND RESULTS Plaques were largest in the combined SS+Cpn-exposed mice with 12-57% greater cross-sectional area compared with all other groups (P<0.03). Quantitative RT-PCR (qRT-PCR) from aortic roots revealed a synergistic upregulation of both OX40L (CD134L) and MyD88 in SS+Cpn mice (P<0.05). This upregulation occurred despite decreased numbers of macrophage, dendritic cell, CD4 T cell and smooth-muscle-cell infiltrates as determined by quantitative IHC and qRT-PCR. To elucidate whether enhanced apoptosis correlated with reduced plaque cellularity, area of Tdt-mediated dUTP nick labeling positive (TUNEL+) cells and expression of key bridging molecules necessary for efferocytosis (Mertk, Tgm2, FasL and C1qa) were examined. In SS+Cpn mice, there was an increase of the area of TUNEL+ cells in plaque cores (P<0.001) and a downregulation of efferocytosis gene expression (P<0.05). Systemic expression of cytokines in sera (Luminex) showed no differences between groups, suggesting that focal disease mechanisms within the plaque predominated. CONCLUSIONS The combination of SS exposure and Cpn infection enhanced atherosclerosis more than either variable did independently by activating inflammatory cells and by promoting growth and maturation of lesions via defective phagocytic clearance and accumulation of apoptotic cells.

Mapping the viral genetic determinants of endothelial cell tropism in human cytomegalovirus

Endothelial cells are natural sites of infection for human cytomegalovirus (HCMV) and are increasingly recognized to play an important role in viral dissemination, as well as provide access to underlying tissues and organs. However, the viral factors required for endothelial cell tropism are poorly defined. The goals of the project were to develop a system to study endothelial cell infectivity factors in HCMV, and map the viral genetic determinants required for these tropism functions. HCMV infection of primary aortic endothelial cells (AEC) was studied as a means to evaluate aspects relevant to both pathogenesis of acute infection and chronic vascular diseases. A series of HCMV virus strains was screened for endothelial tropism by comparing replication efficiencies on AEC. A virus strain that was efficient for replication (AD169varATCC), and a virus strain that was restricted for replication (Toledo), were selected for further analysis and characterization. We present evidence for a novel HCMV endothelial tropism factor that functioned following viral internalization across the endothelial cell plasma membrane and prior to nuclear entry. This factor may be involved in intracellular transport of the virion capsid-tegument structure. Complementation approaches using pseudotype virus infection of AEC demonstrated that the tropism defective strain could be rescued in trans. This supported the existence of a viral encoded tropism determinant. Using a gain of function approach, endothelial cell infectivity of the non-tropic HCMV strain Toledo was rescued with AD169 cosmid sequences. Tropism-specific viral genetic determinant(s) may be mapped to a region of the AD169 viral DNA encompassing UL48-56.

Bartonella Endocarditis–Associated Glomerulonephritis: A Case Report and Review of the Literature

Infectious endocarditis is associated with a number of systemic manifestations, including kidney disease. Kidney manifestations, including hematuria, parenchymal infarction, and glomerulonephritis, may affect as many as 40%-50% of patients with infective endocarditis. In a minority of cases of infective endocarditis, routine bacterial cultures do not yield an offending organism. Bartonella species are a known and relatively common cause of culture-negative endocarditis and have been associated with the development of endocarditis-associated glomerulonephritis. We present a case of Bartonella endocarditis-associated glomerulonephritis in which recognition of a characteristic immunofluorescent pattern and thorough investigation of the clinical history led to this uncommon diagnosis.

Chondrolysis of the Tibial Plateau Caused by Articular Aspergillosis After ACL Autograft Reconstruction: Management with a Fresh Osteochondral Allograft

Arthroscopically assisted reconstruction of the anterior cruciate ligament (ACL) is a common and effective method for treatment of anterior knee instability following ACL injury. Annually, an estimated 250,000 ACL injuries are diagnosed and approximately 100,000 ACL reconstructions are performed in the United States1-3. Chondrolysis is an extremely rare but devastating complication following ACL reconstruction. It is characterized by complete destruction of the articular cartilage and a profound inflammatory response consisting of pain, swelling, and loss of joint motion. The differential diagnosis includes osteonecrosis, direct trauma related to the injury or to the surgical procedure, infection, an adverse reaction to pharmacological agents (including local anesthetic infusions), and unknown causes. Infection after arthroscopic ACL reconstruction is rare: its incidence has been reported as 0.14% to 1.7%2,4-7. The most common causative organisms are Staphylococcus aureus, Staphylococcus epidermidis, and Staphylococcus haemolyticus 2,4-6. When tissue allografts have been used for ACL reconstruction, other organisms such as Peptostreptococcus, Klebsiella, Enterobacter, and Clostridium species as well as gram-negative bacilli have been implicated6,8. Although infrequent, infection can be a devastating complication that leads to septic arthritis, chondrolysis, osteomyelitis, osteochondral destruction, and, in rare cases, death2,5,8,9. We describe a case of medial tibial plateau osteochondral destruction secondary to an Aspergillus flavus fungal infection in an immunocompetent thirteen-year-old girl who had undergone elective ACL reconstruction. The patient and her parents were informed that data concerning the case would be submitted for publication, and they provided their consent. To the best of our knowledge, a case of Aspergillus fungal arthritis following ACL reconstruction has not been previously reported. Furthermore, salvage options outlined in the literature have been limited to primary arthrodesis, prosthetic reconstruction, use …

A 7-year-old girl with ulcerative lesion after a rodent bite.

A previously healthy 7-year-old girl was bitten on the hand by a wild rat after she mistook the rat for a toy and tried to retrieve it from her dog’s mouth. The bite, which occurred on the lateral aspect of the proximal interphalangeal joint of the right index finger, initially healed, but then developed a painless erythematous papule at the bite site 1-week later. The papule ulcerated and the ulcer continued to progress with time. The patient reported moderate pain with movement of the affected finger but little discomfort without movement. She denied systemic symptoms and fever. She did not have a history of travel outside the United States. The patient was treated sequentially with amoxicillin-clavulanate, trimethoprimsulfamethoxazole, and clindamycin without response. Bacterial culture of a superficial swab grew only Candida albicans. The patient was administered with topical antifungal and oral fluconazole. The ulceration continued to progress without response and the patient was referred to the pediatric infectious diseases clinic for evaluation. On physical examination, the patient appeared healthy and vital signs were normal. She had a 1 1 cm ulcerative lesion (Fig. 1) on the lateral aspect of the proximal interphalangeal joint of the right index finger. This was tender to palpation and with flexion of the finger. There were multiple enlarged right axillary lymph nodes that were nontender and mobile. The overlying axillary skin was nonerythematous. The rest of the physical examination was normal. Blood count and chemistry panels were both normal and radiographs did not show bone or joint involvement. A deep tissue biopsy of the lesion site was performed which led to a definitive diagnosis.