Tags: Endocarditis

Penicillium Infections

Essentials of Diagnosis Penicillium marneffei infection found in both immunocompetent and immunosuppressed patients. P marneffei found in Southeast Asia and southern China. Mold, septate hyphae 1.5-5 um in diameter. May be cultured from a variety of specimens including blood. Penicillium spp. other than P marneffei occur worldwide. Infection with Penicillium spp. is rare; occurs in immunosuppressed patients. General Considerations A. Epidemiology. Penicillium spp. are ubiquitous in nature and may be recovered with ease from a variety of sources within the hospital environment. These molds commonly contaminate clinical specimens and cause contamination in the laboratory. Colonization of nonsterile anatomical sites in humans is common. In most cases where Penicillium spp. are recovered …

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Aspergillus, Pseudallescheria, & Agents of Mucormycosis

ASPERGILLUS INFECTION Essentials of Diagnosis Filamentous fungus with septate hyphae 3-6 um in diameter. Branching of hyphal elements typically at 45° angle. Specific IgG antibodies generally of no use diagnostically since most patients are immunosuppressed and will not generate antibody response. Pulmonary lesions, localized or cavitary in susceptible host. General Considerations A. Epidemiology. Aspergillus spp. are found worldwide and grow in a variety of conditions. They commonly grow in soil and moist locations and are among the most common molds encountered on spoiled food and decaying vegetation, in compost piles, and in stored hay and grain. Aspergillus spp. often grow in houseplant soil, and such soil may be a source of …

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Mucormycosis: Clinical Syndromes

1. RHINOCEREBRAL MUCORMYCOSIS Rhinocerebral mucormycosis occurs most commonly in patients with uncontrolled diabetes, especially after an episode of diabetic ketoacidosis. It may also occur in leukemic patients who have had prolonged neutropenia and therapy with broad-spectrum antibiotics and occasionally in organ transplant recipients. Clinical Findings A. Signs and Symptoms. The earliest symptoms in rhinocerebral mucormycosis are facial pain, headache, and nasal stuffiness. As the disease progresses, orbital pain and facial anesthesia may be noted. Double vision or loss of vision may develop after invasion of the orbit by the rapidly spreading infection. Mental status changes herald the penetration into the brain with ensuing cavernous sinus thrombosis, carotid artery thrombosis, and cerebral …

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Candida Species

Essentials of Diagnosis Characteristic appearance of yeast and hyphae on KOH preparations. Formation of germ tubes in serum is presumptive diagnosis for Candida albicans. Cultures must be interpreted with caution because positive culture may represent colonization rather than infection. Serology not useful. General Considerations A. Epidemiology. Candida organisms are commensal with humans and, in the absence of alterations in host defense mechanisms, usually do not cause disease. Candida exists as normal flora within the oral cavity, throughout the gastrointestinal (GI) tract, in expectorated sputum, in the vagina, and in the bladder of patients with indwelling catheters. There are >150 species within the genus Candida, although the majority are not known to …

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Histoplasma Capsulatum

Essentials of Diagnosis Thin-walled oval yeast measuring 2-4 mm in diameter. Dimorphic: mycelial in nature, yeast in tissue. Endemic within Ohio and Mississippi River Valleys. Associated with activities that disturb dust or soil enriched with bird, chicken, and bat excrement. Complement fixation antibody titer 1:32 or greater. Simultaneous appearance of anti-H and anti-M antibodies. Infection most often is asymptomatic or may cause chronic pulmonary infection; less commonly, disseminated infection involving the adrenals, ulcerative gastroenteritis lesions, or central nervous system. Recovery of organism from culture of tissue, blood, sputum, or other source. General Considerations A. Epidemiology. Histoplasma capsulatum, the etiologic agent of histoplasmosis, is an endemic, dimorphic fungus that causes a wide …

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Bartonella

Essentials of Diagnosis Key signs and symptoms include dermal lesion (bacillary angiomatosis and chronic phase of Bartonella bacilliformis infection); papule at inoculation site followed by proximal lymphadenopathy (cat scratch disease); fever, bacteremia, acute hemolytic anemia (acute phase of B bacilliformis infection); persistent or relapsing fever (fever and bacteremia/endocarditis). Predisposing factors include louse exposure, low income, and homelessness (Bartonella quintana-associated bacillary angiomatosis, fever, and bacteremia/endocarditis); cat exposure (cat scratch disease and Bartonella henselae-associated bacillary angiomatosis, fever and bacteremia/endocarditis); sandfly exposure in endemic areas of South American Andes (B bacilliformis infection). History of HIV or immunocompromise (bacillary angiomatosis). Key laboratory findings include small, curved, pleomorphic weakly gram-negative bacilli, best visualized with Warthin-Starry silver …

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Fever & Bacteremia/Trench Fever/Endocarditis

The four Bartonella species that are pathogenic for humans are capable of causing sustained or relapsing bacteremia accompanied by only fever (Table 1). All except B bacilliformis also cause endocarditis. After B quintana enters the body through broken skin from the excreta of the infected human body louse (Pediculus humanus), there is an incubation period of between 5 and 20 days before the onset of trench fever. Patients complain of fever, myalgias, malaise, headache, bone pain — particularly of the legs, and a transient macular rash. Usually the illness continues for 4-6 weeks. Sustained or recurrent bacteremia is common, with or without symptoms. The form of trench fever described in the …

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Coxiella, Ehrlichia, & Rickettsia

Coxiella, Ehrlichia, and Rickettsia spp. are small, obligate intracellular bacteria that usually cause disease when they accidentally encounter a human host. Once inside a host cell, Coxiella and Ehrlichia spp. remain within a vacuole where they progress through distinct developmental stages; in contrast, the Rickettsia spp. escape the endocytic vacuole and replicate within the host cell cytoplasm. Ehrlichia and Rickettsia spp. are transmitted by arthropod vectors. COXIELLA BURNETII INFECTION (Q FEVER) Essentials of Diagnosis Acute Infection Key symptoms and signs: fever, severe headache, myalgias, arthralgias, retrobulbar pain, cough; possible pneumonitis and hepatitis on examination. Predisposing factors: occupation as a dairy farmer, abattoir worker, or veterinarian; exposure to parturient or newborn animals, …

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Chlamydia

General Considerations Chlamydia trachomatis, Chlamydia psittaci, and Chlamydia pneumoniae are among the most prevalent microbial pathogens in humans worldwide. C trachomatis is responsible for a variety of sexually transmitted disease (STD) syndromes in both sexes. In addition, certain serotypes of C trachomatis are responsible for trachoma, the most common infectious cause of blindness in humans. C psittaci is a zoonotic pathogen associated with atypical pneumonia. C pneumoniae infects approximately one-half of the world’s human population and is a cause of upper and lower respiratory tract disease. It has also been associated with atherosclerotic cardiovascular disease. A. Epidemiology. In the United States, genital infections by C trachomatis serovars D through K occur …

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Chlamydia Psittaci Infections

Essentials of Diagnosis History of contact with birds. Positive C psittaci-specific microimmunofluorescence serologies. Positive complement fixation titers (not species specific). Clinical Findings A. Signs and Symptoms. Pneumonia, pericarditis, myocarditis, and endocarditis have been attributed to C psittaci infection (psittacosis or ornithosis) (Box 5). The incubation period for the pneumonia is usually 1-2 weeks. Its onset is gradual with body temperature increasing over a period of 5-7 days; however, there are cases in which the onset is sudden with rigors and temperatures as high as 104 °F. Headache is a salient and important symptom; it can be severe and incapacitating. Cough is usually nonproductive and hacking; however, on occasion a mucoid sputum …

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