| - 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 |
| fungi that can be a yeast at 37C or molds at room temperature | Dimorphic |
| 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 |
| room temperature or 22-25 C | Molds |
| Organisms that cause classic systemic fungal diseases have historically
been categorized together because they share several characteristics, such as mode of transmission, dimorphism, and
systemic dissemination | Systemic Mycoses |
| Conversion to the yeast or spherule form occurs when it is incubated at 35° to 37° C on enriched media with increased concentration of | CO2 |
| The diseases are contracted
generally by the inhalation of infectious conidia | Systemic Mycoses |
| 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 |
| requiring two mating strains
to produce the sexual form. | heterothallic |
| 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 |
| The mycelial phase of the systemic dimorphic fungi—B.
dermatitidis, B. gilchristii, Cocccidioides immitis, Cocccidioides
posadasii, Histoplasma capsulatum, and Paracoccidioides
brasiliensis—requires confirmatory identification, typically | DNA probe and DNA sequencing |
| 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 |
| - not commonly encountered
- Can be acquired through inhalation of their arthroconidia and can produce Primary Coccidioidomycosis | - Posadasii |
| • 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 |
| found in the desert areas of the Southwest
United States, Mexico, and South America. | C. posadasii |
| 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 |
| - Giemsa and Wright stain: small, budding, round to oval yeast cells; intracellular to mononuclear cells
The small cells, when found in tissue, resemble the blastoconidia of Candida glabrata, but they can be differentiated by fluorescent antibody (FA) techniques or culture. | Yeast 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 |
| H. capsulatum antigen can be detected from
serum, CSF, and urine with a sensitivity of about | 95% |
| 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 |
| Primary route of infection for Paracoccidioides brasiliensis is | Inhalation |
| 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 |
