Tags: Bronchitis

Trematodes

Essentials of Diagnosis Blood flukes: demonstration of eggs in feces, urine, or rectal biopsy Liver flukes: demonstration of eggs in feces Intestinal flukes: demonstration of adult worms or eggs in feces Lung flukes: demonstration of eggs in sputum or feces All trematode species that are parasitic for humans are digenetic. Sexual reproduction in the adult fluke is followed by asexual multiplication in the larval stage. Most species of adult trematodes have an oral and ventral sucker. The life cycles of trematodes that are important human pathogens are similar among all five major species. Eggs are excreted in the feces of the host, hatch in fresh water, and require a primary host …

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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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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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Mycoplasma & Ureaplasma

Mycoplasma and Ureaplasma species (mycoplasmas) are ubiquitous in nature and are commonly found in plants, animals, and humans. These bacteria contain the smallest amount of double-stranded DNA that is capable of producing a free-living microorganism; they measure between 0.15 and 0.3 um in diameter and = 2 um in length. They are believed to have evolved from a putative common ancestor of the gram-positive bacteria by a process of genome reduction and adoption of a dependent, parasitic life style. Mycoplasma and Ureaplasma spp. lack a cell wall. Therefore, they cannot be visualized with the Gram stain and are not susceptible to antibiotics that act on cell wall synthesis (eg, penicillins and …

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Mycoplasma Pneumoniae Infection & Disease

Mycoplasma Pneumoniae is an important cause of upper and lower respiratory infections in both adults and children. Extrapulmonary involvement, including dermatological, neurological, cardiac, musculoskeletal, and vasculitic involvement, has also been associated with M pneumoniae infection in humans. Essentials of Diagnosis Community acquired pneumonia. Extrapulmonary involvement is not infrequent. Inflammatory cells on sputum Gram stain but no predominant bacterial type. Coombs-positive hemolytic anemia. Cold agglutinin titer of = 1:32. Fourfold change in specific immunoglobulin G (IgG) or IgM titers. General Considerations A. Epidemiology. Infected humans are the only source of M pneumoniae organisms for transmission to new susceptible hosts. M pneumoniae is spread from one individual to another by respiratory droplets produced …

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Nocardia

Essentials of Diagnosis Gram-positive, variably acid-fast, branching filaments with aerial hyphae. Colonies have characteristic chalky-white or cotton ball appearance. Suspect when chronic pulmonary disease is accompanied by CNS or skin lesions. No specific antibody or antigen detection tests. General Considerations A. Epidemiology. Nocardia spp. are strictly aerobic, ubiquitous soil-dwelling organisms that are largely responsible for the decomposition of organic plant material. Infection usually occurs via inhalation of these organisms in airborne dust particles, leading to pulmonary disease. However, infection can also be acquired via direct percutaneous inoculation by thorns, animal scratches, bites, surgical wounds, and intravenous catheters. Dissemination commonly occurs to the central nervous system (CNS), skin, and subcutaneous tissues. Nocardiosis …

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Haemophilus, Bordetella, & Branhamella Species

HAEMOPHILUS INFLUENZAE & OTHER HAEMOPHILUS SPECIES Essentials of Diagnosis • Haemophilus influenzae is generally acquired via the aerosol route or by direct contact with respiratory secretions. • The most common associated syndromes include otitis media, sinusitis, conjunctivitis, bronchitis, pneumonia, and, to a lesser extent, meningitis, epiglottitis, arthritis, and cellulitis. • Gram stain shows pleomorphic gram-negative coccobacilli. • In cases of meningitis, epiglottitis, arthritis, and cellulitis, organisms are typically recovered from blood, and type-b polysaccharide capsular material may be detected in the urine. • Organisms and type-b polysaccharide capsule may also be present in other appropriate sterile body fluids, such as cerebrospinal fluid (CSF) in meningitis and joint fluid in arthritis. General …

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Branhamella Catarrhalis: Clinical Syndromes

B catarrhalis causes bronchitis and pneumonia in patients with underlying lung disease, especially chronic obstructive pulmonary disease. It is also a rare cause of invasive disease, including meningitis, endocarditis, bacteremia without a focus, septic arthritis, and cellulitis. In addition, it is a recognized cause of acute conjunctivitis and is periodically mistaken as Neisseria gonorrhoeae in newborn infants with conjunctivitis. B catarrhalis occasionally colonizes the genital mucosa and has been reported as a cause of urethritis. Clinical Findings A. Signs and Symptoms. The signs and symptoms of B catarrhalis acute otitis media and sinusitis are indistinguishable from those present when acute otitis media and sinusitis are caused by other pathogens (Box 8). …

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Haemophilus Influenzae: Clinical Syndromes

H influenzae was first isolated during the 1892 influenza pandemic and was originally believed to be the causative agent of influenza. Although subsequent studies revealed the fallacy of this idea, H influenzae has proved to be a common cause of localized respiratory tract and systemic disease, including meningitis, epiglottitis, pneumonia, pyogenic arthritis, cellulitis, otitis media, and sinusitis, among others (Box 1). 1. MENINGITIS Meningitis is the most common and serious form of invasive H influenzae type-b disease. In the mid-1980s, before the introduction of effective vaccines, ~ 10,000-12,000 cases of H influenzae type-b meningitis occurred in the United States each year, and 95% of cases involved children < 5 years old. …

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Pseudomonas Aeruginosa

Essentials of Diagnosis • Nosocomial acquisition. • Predisposing factors include immunosuppression (neutropenia, cystic fibrosis [CF], AIDS, corticosteroid use, diabetes mellitus); presence of a foreign body, prosthesis, or instrumentation; prolonged hospitalization and antibiotic use; intravenous drug use. • Most common infections include pneumonia, bacteremia, urinary tract infection, otitis media, skin and skin structure infections, including ecthyma gangrenosa. • Gram stain shows gram-negative bacilli; recovery of microorganism from culture of blood or other tissue. General Considerations A. Epidemiology. The genus Pseudomonas consists of a number of human pathogens, the most important of which is Pseudomonas aeruginosa. P aeruginosa is an opportunistic pathogen found widely in soil, water, and organic material, reflecting its limited …

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