Microvirology
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Microvirology - Details
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| 🇬🇧 | 🇬🇧 |
| - Caused by mostly dimorphic fungi - It is an internal infection and can be acquired from inhalation of the pathogen from the nature. | Systemic Mycoses |
| The test for Systemic Mycoses | Exo-antigen test |
| Disease: North American Blastomycosis or Gilchrist / Chicago disease | Blastomyces dermatitidis |
| Primary infections exhibit flu like symptoms, most of the patients are asymptomatic | Blastomyces dermatitidis |
| If we failed to resolve the primary infection of Blastomyces dermatitis it can progress to pulmonary or invasive disease which is the | Ulcerative lesions |
| If the patient is Immunodeficient B. dermatitis can lead to | Multiple Organ System Infection |
| B. dermatitidis natural reservoir is mostly from | Soil or Nature/Environment |
| It is a teleomorph or sexual form, does not occur in the routine laboratory. Required two mating strains to produce the | Gajellomyces dermatitidis |
| Laboratory Diagnosis: - Microscopic detection in tissue - KOH (10%) or Calcofluor white: used to enhance the detection of yeast cells | Blastomyces dermatitidis |
| Short lateral branches with round or pyriform conidia borne singly or directly on hyphae; resembling “lollipops” | Mold phase of B. dermatitidis |
| Double-contoured walled: large yeast cells with bud on broad base | Yeast phase of B. dermatitidis |
| 37 C | Yeast |
| Slow to moderate growth White to dark tan Young colonies tenacious, older colonies glabrous to woolly | Blastomyces dermatitidis |
| Slow growth White to dark tan with age Woolly, cottony, or granular | Histoplasma capsulatum |
| Rapid growth White to tan to dark gray Young colonies tenacious, older colonies cottony Tend to grow in concentric rings | Coccidioides immitis, Coccidioides posadasii |
| Slow growth White to beige Colony glabrous, leathery, flat to wrinkled, folded or velvety | Paracoccidioides brasiliensis |
| Oval, pyriform to globose smooth conidia borne on short, lateral hyphalike conidiophores | Blastomyces dermatitidis |
| Microconidia small, one celled, round, smooth (2–5 μm) Tuberculated macroconidia large, round (7–12 μm) Hyphalike conidiophores | Histoplasma capsulatum |
| Alternating one-celled, “barrel-shaped” arthroconidia with disjunctor cells | Coccidioides immitis, Coccidioides posadasii |
| Colonies frequently only produce sterile hyphae. Fresh isolates may produce conidia similar to those of B. dermatitidis | Paracoccidioides brasiliensis |
| Blood agar, 37° C | Blastomyces dermatitidis |
| Pines medium, glucose-cysteineblood, or BHI agar–blood, 37° C | Histoplasma capsulatum |
| BHI agar–blood agar, 37° C | Paracoccidioides brasiliensis |
| Large yeast (8–12 μm) Blastoconidia attached by broad base | Blastomyces dermatitidis |
| Small, oval yeast (2–5 μm) | Histoplasma capsulatum |
| Multiple blastoconidia budding from single, large yeast (15–30 μm) | Paracoccidioides brasiliensis |
| Can be converted to the spherule phase in modified Converse medium at 40° C in 5% to 10% carbon dioxide | Coccidioides immitis |
| Most prevalent in middle-aged men | Blastomyces dermatitidis |
| Mississippi and Ohio river valleys | Blastomyces dermatitidis |
| Ohio, Missouri, and Mississippi river valleys Bird and bat guano Alkaline soil | Histoplasma capsulatuma |
| Semi-arid regions— southwest United States, Mexico, Central and South America In soil | Coccidioides immitis, C. posadasii |
| Central and South America In soil | Paracoccidioides brasiliensis |
| Thick-walled yeasts (15–30 μm) Multiple buds, “mariner’s wheel” | Paracoccidioides brasiliensis |
| Endemic in Central Africa. | Histoplasma capsulatum var. duboisii |
| Only a very narrow range of conditions supports its growth | Blastomyces dermatitidis |
| Natural disease occurs in dogs and horses, with the disease process mimicking that seen in human infections. | Blastomyces dermatitidis |
| May be used to enhance the detection of the yeast cells. | KOH (10%), or calcofluor white |
| Raised areas, termed spicules, are seen in the centers of the colonies | Blastomyces dermatitidis |
| Major Biological Hazard among Laboratory Personnel | Coccidioides immitis |
| Are probably the most virulent of all human mycotic agents. | Coccidioides Species |
| Inhalation of only a few arthroconidia produces | Primary coccidioidomycosis |
| Clinical infections include asymptomatic pulmonary disease and allergic manifestations | Coccidioides Species |
| Primary disease usually resolves without therapy and confers a strong, specific immunity to reinfection, which is detected by the | Coccidioidin skin test |
| • Toxic Erythema • Erythema nodosum or Dessert bumps • Erythema multiforme or Valley fever • Arthritis or dessert rheumatism | Coccidioides immitis |
| - In symptomatic patients’ fever, respiratory distress, cough, anorexia, headache, malaise, and myalgias can manifest | For 6 weeks or longer |
| Which can include nodules, cavitary lung disease, and/or progressive pulmonary disease. | Secondary coccidioidomycosis |
| - Histopathologic examination of tissues and other specimens - Direct visualization of endosporulating spherules | Coccidioides immitis |
| - Thick-walled, barrel-shaped, rectangular arthroconidia that alternate with empty disjunctor cells | Mold phase of Coccidioides immitis |
| - Large, round, thick-walled spherules with endospores observed in tissues and direct examination. | Yeast phase of Coccidioides immitis |
| Filipinos and blacks run the highest risk of dissemination, with meningeal involvement being a common result of disseminated disease. | Coccidioides immitis |
| Coccidioides spp. reside in a narrow ecologic niche known as the(blank) which is characterized by low rainfall and semi-arid condition | Lower Sonoran life zone, |
| Is encountered in the San Joaquin Valley region of California, | Coccidioides immitis |
| At maturity, the spherules (30 to 60 μm) produce endospores by a process known as | Progressive cleavage |
| May reveal the spherules containing the endospores of C. immitis | Direct smear examination of secretions |
| May resemble the yeast cells of B. dermatitidis, and the endospores can be confused with the cells of C. neoformans, H. capsulatum, and P. brasiliensis | Coccidioides immitis |
| Mature colonies usually turn tan to brown to lavender in color | Coccidioides immitis |
| Disease: Histoplasmosis, reticuloendothelial cytomycosis, Darlings or Spelunkers Disease, Cave Disease | Histoplasma capsulatum |
| Acquired by inhalation of the microconidia | Histoplasma capsulatum |
| With the only sequelae being areas of calcification in the lungs, liver, and spleen | Histoplasma capsulatum |
| In the mild form of the disease, viable organisms remain in the host, quiescent for years, and are the presumed source of reactivation | Histoplasma capsulatum |
| In patients with chronic obstructive pulmonary disease may also occur | Chronic pulmonary histoplasmosis |
| Other various manifestations of the disease are mediastinitis, pericarditis, and mucocutaneous lesions | Histoplasma capsulatum |
| This organism resides in soil with a high nitrogen content, particularly in areas heavily contaminated with bat and bird guano | Histoplasma capsulatum |
| Convert mold form into yeast form using Brain Heart Infusion Agar, incubated at 37°C, is confirmatory for | Histoplasma capsulatum |
| Using enzyme immunoassay (EIA) methods, H. capsulatum antigen can be detected from a variety of clinical specimens, includ | Blood, CSF, and urine. |
| Most useful serologic test to diagnose Histoplasmosis. It is used to test the TITERS | Combination of complement fixation and Immunodiffusion test |
| Large tuberculated macroconidia | Mold phase of Histoplasma capsulatum |
| Causes epizootic lymphangitis in horses and mules | H. capsulatum var. farciminosum |
| Like B. dermatitidis, is a heterothallic ascomycete that produces a teleomorphic state, Ajellomyces capsulatus, when mated with appropriate tester strains. | Histoplasma capsulatum |
| Resemble the blastoconidia of Candida glabrata, but they can be differentiated by fluorescent antibody (FA) techniques or culture. | Histoplasma capsulatum |
| The most useful test for rapid diagnosis of histoplasmosis is the combination of a | DNA hybridization system and DNA sequencing |
| Disease: Paracoccidioidomycosis, South American blastomycosis, Brazilian blastomycosis, Lutz-Splendore-Almeida disease, paracoccidioidal granuloma | Paracoccidioides brasiliensis |
| Subsequent dissemination leads to the formation of ulcerative granulomatous lesions of the buccal, nasal, and occasionally gastrointestinal mucosa | Paracoccidioides brasiliensis |
| Geographic areas of highest incidence are typically humid, high-rainfall areas, with acidic soil conditions. | Paracoccidioides brasiliensis |
| Small, one-celled conidia | Mold phase of Paracoccidioides brasilienses |
| Multipolar budding at the periphery that resembles a ship wheel/pilot wheel/mariners’ wheel- connected by a narrow base “Mickey Mouse Cap” | Yeast Paracoccidioides brasilienses |
| A concomitant striking lymph node involvement is also evident | Paracoccidioides brasilienses |
| Has a rather narrow range of temperature tolerance, as evidenced by its predilection for growth in cooler areas of the body (nasal and oropharyngeal), | Paracoccidioides brasilienses |
| A common cause of systemic infection in immunocompromised patients who have visited the endemic region of Southeast Asia | Talaromyces marneffei |
| Resemble those of H. capsulatum, oval to cylindric, measuring 3 to 6 µm long, and may have a cross-wall. | Talaromyces marneffei |
| - Infections are usually disseminated, with multiple organ involvement - Can be isolated in lesions of infected patients | Talaromyces marneffei |
| - Polymerase chain reaction tests have been described for identification confirmation. | Talaromyces marneffei |
| - Sparse green aerial and reddish-brown vegetative hyphae and production of a red diffusible pigment | Mold phase of Talaromyces marneffei |
| - Exhibits a transverse septum and intracellular in vivo | Yeast phase of Taloromyces marneffei |