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Microbiology 11


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What are the general "suggestives of" for aseptic vs septic meningitis?
Mononuclear cells, normal or near normal glucose, and mild to moderate protein in CSF is suggestive of aseptic meningitis

Pins, low glucose, and higher protein elevation is suggestive of septic meningitis

there are exceptions . . .
- what type of colonies
- cell appearance
- hyphae?
smooth, creamy colonies

round or oval cells, reproduce by budding

true hyphae (straight, parallel walls), pseudohyphae (chains of sausages)
- what type of colonies
- hyphae?
produce fuzzy colonies due to production of aerial hyphae

true hyphae

septate: aspergillus, fusarium, pseudoallescheria

aseptate: rhizomucor

dematiaceous: pigmented

hyaline: unpigmented
spores, fruiting bodies

infectious particles that lead to disease (inhaled --> pneumonia, skin trauma --> lesions)
tinea capitis
tinea pedis
athlete's foot
tinea cruris
jock itch (groin region)
tinea corporis
tinea barbae
beard area
tinea unguium
what are the three genera of dermatophytes?
(1) epidermophyton

(2) microsporum

(3) trichphyton
Trichophyton, Microsporum, Epidermophyton
- skin/hair/nails?

get it?
Tinea pedis
- caused by which genus?
can be caused by all 3 dermatophytes; most commonly due to Trichphyton species
Tinea capitis
- caused by which genus?
if only skin --> epidermophyton

if skin + hair shaft --> trichophyton, microsporum
Tinea cruris
- caused by which genus?
Tinea unguium
- caused by which genus?
which species are involved in rash in chronically warm, moist areas (e.g. diaper rash)?
candida species
malassezia furfur
causes tinea versicolor
exophilia werneckii
tinea nigra, brown or black macules with well defined borders on palms and soles
trichosporon beigelli
white piedra, bloodstream infection in patients with neutropenia
what are the four clinically important subcutaneous syndromes?
(1) mycetomas

(2) chromoblastomycosis

(3) phaeohyphomycosis

(4) sporotrichosis
- caused by?
- appearance
- 4 e.g.
caused by dematiaceous (pigmented) fungi

verrucous (cauliflower-like) dermatitis; appear as brown, septate, yeast-like cells (sclerotic bodies)

e.g. Fonesecaea pedrosi, F. compactum, Cladosporium carionni, Phialophera verrucosa
- caused by?
- appearance
- 3 e.g.
caused by dematiaceous fungi

hyphal in morphology

e.g. exophilia, phialophera, curvularia
- aka
- e.g.
Drunken Rose Gardeners Disease

sporothrix schenkii
what is the treatment for drunken rose gardeners disease?
oral itraconazole, IV amphotericin-B
cause of blastomycosis
blastomyces dermatitides
cause of coccidioiomycosis
coccidioides immitis
cause of histoplasmosis
histoplasma capsulatum
cause of paracoccidioidomycosis
paracoccidioides brasiliensis
cause of sporotrichosis
sporothrix schenckii
blastomycosis treatment
amphotericin B, itraconazole
what are the two drugs approved for the treatment of coccidioidomycosis?
amphotericin B, fluconazole
treatment for histoplasma capsulatum
amphotericin B, itraconazole
treatment for aspergillosis
voriconazole, amphotericin B, itraconazole
yeast general picture
unicellular, produce by budding
when yeast buds do not separate, can form long chains of cells
threadlike, branching, cylindrical tubules composed of fungal cells attached end to end
aka mycelia

multicellular colonies composed of clumps of intertwined branching hyphae; molds grow by longitudinal extension and produce spores
reproducing bodies of molds
dimorphic fungi
can grow as either a yeast or mold, depending on environmental conditions and temperature
fungi that live in and utilize organic matter (soil, rotten vegetation) as an energy source
what do amphotericin B and ketoconazole do to fungal cell membrane?
amphotericin B binds to ergosterol and punches holes in the fungal cell membrane, while ketoconazole inhibits ergosterol synthesis
which fungus causes pityriasis versicolor (aka tinea versicolor)?
malassezia furfur
which fungus causes tinea nigra?
exophiliala werneckii
three fungi that cause systemic disease in humans
histoplasma capsulatum, blastomyces dermatitidis, and coccidioides immitis
inflammation of the brain
inflammation of leptomeninges
inflammation of spinal cord
what is the hallmark of encephalitis?
alteration in consciousness, lethargy or coma
is aspergillus going to display septate or aseptate hyphae?
give two examples of dimorphic molds
(1) blastomyces dermatiditis

(2) histoplasma capsulatum
what is the most important distinction to remember between chromoblastomycosis and phaeohyphomycosis?
chromo are yeast-like

phaeo are hyphal
what is the most common cause of meningitis in AIDS patients?
Cryptococcus neoformans
desc basics of mucormycosis
occurs most commonly in poorly controlled diabetics with acidosis and patients with severe neutropenia (rare in AIDS)

invades blood vessels! --> get tissue necrosis (black discharges, eschars)

treatment: Amphotericin B + surgical debridement of necrotic tissue
what is the agent of Amebiasis?
entamoeba histolytica
refers to all infections caused by E. histolytica

disease of the large intestine due to invasion of the submucosa by E. histolytica
amebic dysentery
aka acute amebiasis

refers only to acute cases with bloody diarrhea and acute abdominal pain
hepatic amebiasis
hepatomegaly, tenderness over the liver, and referred pain in the region of the right shoulder
should you give corticosteroids in acute amebic colitis?
acute amebic colitis
- diagnosis
microscopic identification of trphozoites or cysts from stool or culture
hepatic amebiasis
- diagnosis
find trophozoites in aspirated specimens from the margin of an abscess
Giardiasis agent
Giardia lamblia (flagellate)
- ID
- Symptomatology
- Diagnosis
infection of small intestine

abdominal pain and diarrhea; malodorous, very mucous stools (steatorrhea-fatty stools) are often noted from children with acute infections

diagnosis is made by finding cysts informed stools, and trophozoites or cysts in diarrheic feces
what is the agent for Trichomoniasis?
Trichomonas vaginalis (flagellate)
common protozoan UTI; transmission primarily through sexual intercourse; only trophozoites occur
treatment for trichomoniasis
metronidazole; both male and female sexual partners must be treated
agent of primary amebic meningoencephalitis
Naegleria fowleri (ameba)
diagnosis of primary amebic meningocephalitis
spinal puncture reveals a sanguinopurulent fluid; total leukocyte count may be as high as 24,000/cu mm with 92% neutrophils
what are the causative agents of Granulomatous Amebic Encephalitis - Amebic keratitis?
Acanthameba spp.
Granulomatous amebic encephalitis
occurs in debilitated and chronically ill individuals and those undergoin immunosuppressive therapy

CNS infection, necrosis of CNS tissue with chronic inflammation and granulomatous tissue
causative agent of Toxoplasmosis
Toxoplasma gondii (sporozoan)
toxoplasmosis diagnosis
Sabin-Feldman dye test and complement fixation and hemagglutination tests
what are the causative agents of Malaria (Sporozoa)
Plasmodium vivax, P. malariae, P. ovale, P. falciparum
is a mosquito-borne disease of man resulting from infection of the parenchymal cells of the liver and the RBCs by sporozoans belonging to the genus Plasmodium
desc reproduction for the sporozoans responsible for malaria
Plasmodium spp.

Asexual reproduction (schizogony) of the parasite occurs in the erythrocytes of man and sexual reproduction (sporogony) takes place in the mosquito
malaria symptomatology
classic chills and fever syndrome

splenomegaly and anemia
malaria diagnosis
ID malarial parasite in stained blood films
Cutaneous leishmaniasis agent
Leishmania tropica
Mucocutaneous Leishmaniasis agent
Leishmania braziliensis
Leishmaniasis (Cutaneous and Mucocutaneous) general info
disease of skin and mucous membranes characterized by ulcerating lesions

parasites are found intracellularly in mononuclear (macs) and polymorphonuclear leukocytes and epithelial cells

infection aquired through bite of infected female sandflies (Phlebotomus)
Visceral Leishmaniasis (kala-azar) causative agents
Leishmanian donovani (flagellate)
Visceral Leishmaniasis general info
affects primarily the cells of the reticuloendothelial system; female sandflies of the genus Phlebotomus transmit the infection to man; intracellular; fever, anemia, emaciation, splenomegaly, and hepatosplenomegaly
African Trypanosomiasis (African sleeping sickness) causative agents
Trypanosoma gambiense, T. rhdesiense (flagellates)
African Trypanosomiasis
- general info
hematozoan infection of the blood, lymph nodes, and CNS

disease progresses from the acute state with trypanosomes in the blood and then lymphatics to the chronic sleeping sickness stage with invasion of the CNS

parasites are transmitted by the bite of tsetse flies (Glossina); parasites undergo antigenic variation
symptomatology of African Trypanosomiasis
during blood / lymph stages: fever, intense headache, and enlargement of lymph nodes, especially in the posterior cervical triangle (Winterbottom's sign)

CNS: somnolence, emaciation, and eventually coma and death
American Trypanosomiasis (Chagas' disease) causative agents
Trypanosoma cruzi (flagellate)
American Trypanosomiasis general info
hematozoan infection of the blood and tissue

intracellular parasite, cells of RE system (macs), heart and brain

transmitted to man through fecal material of infected blood-sucking reduviid bugs (Reduvidae)
Chagas' disease symptomatology
aka American Trypanosomiasis

acute: fever, hepatosplenomegaly, edema of eyelids (Romana's sign)

later: heart and brain involvement may produce sever myocarditis and meningoencephalitis
American Trypanosomiais treatment
The only medication of any value in treatment of Chagas' disease is Bayer 2502 (a nitrofurfurylidine derivative) given IM
Enterobiasis (Pinworm infection) causative agent
Enterobius vermicularis
Enterobiasis general info
benign intestinal disease more common in children; infection follows ingestion of embryonated eggs; adult worms are found superficially attached to the cecal mucosa
Enterobiasis symptomatology
symptoms are associated with migration and egg deposition of female worms on the perineum; anal pruritis, nervousness and irritability
Enterobiasis diagnosis
scotch tape diagnosis
Ascariasis (Roundworm infection) causative agent
Ascaris lumbricoides (Giant Roundworm)
Ascariasis general info
chronic nematode disease of small intestine

infection is acquired by ingestion of infective eggs

larvae undergo a period of development in the lungs; adults live in the lumen of the small intestine; umembryonated eggs are passed in the stool
Ancylostomiasis (Necatoriasis) -- Hookworm infection
- causative agents
Ancylostoma duodenale, Necator americanus
Ancylostomiasis general info
chronic, debilitation intestinal infection usually exhibiting some degree of anemia; adult hookworms attached to villi of SI; larvae migrate to lungs
hypochromic microcytic anemia
symptom of Ancylostomiasis

bloodsucking activity of adult worms, along with malnutrition, leads to this
Trichinosis agent
trichinella spiralis
Trichinosis general info
nematode disease resulting from the migration and encystment in the muscle of Trichinella larvae; infection is by eating raw or insufficiently cooked meat, chiefly pork, containing encysted larvae
only human nematode infection in which larvae rather than eggs are passed in the feces
Cutaneous Larva Migrans causative agent
Larvae of Ancylostoma caninum, Ancylostoma brasiliense
Cutaneous Larva Migrans
larvae of dog and cat hookworms cause a dermatitis in man called "creeping eruption"; larvae penetrate skin and produce serpiginous tunnels in subcutaneous tissue; pruritis is intense and scratching often leads to secondary bacterial infection
agent: Cysticercus cellulosae (Larva of Taenia solium)

When eggs of Taenia solium are ingested by humans, the larval form is released into the intestine; invades gut wall and migrate to various tissue such as muscle or brain (epilepsy) producing cysticercosis
feeding, dividing, vegetative stage of parasite; causes tissue damage
dormant, inactive stage of parasite; protects the organisms from environment; usually an infective stage
what is the main clinical sign to think of regarding giardiasis? what to avoid?

avoid drinking mountain water
usually a short, self-limited diarrhea

BUT . . . (OTE) . . .

is the causative agent of chronic diarrhea in symptomatic patients with AIDS
diagnosis for cryptosporidiosis?
oocysts in the stool
Acanthameba Karatitis
infection of the cornea generally after trauma associated with contaminated water or contact lens wear
desc Ig with regards to diagnosis of newborn toxoplasmosis
if baby has IgM, that means you have a current infection

if mother has IgG --> just means she was infected in the past
macular rash
papular rash
Petechial rash
non-blaching, often purple-colored, these are always worse
Rocky Mountain Spotted fever
(VA & NC), spring-late fall, ticks found in grass, 3 day history of fever 103-104, malaise and irritability, non-blanching lesions
Scarlet Fever
Strawberry Fields --> strawberry tongue

face: red rash, everywhere except perioral sparing, red lips

SANDPAPER RASH, Pastia's Lines
- a little cold for a day or so
- then quick progression to fever and petechial rash
- extreme lethargy
diffuse macular rash that goes from head --> feet
5th Disease
aka Slapped Cheek, EI
Chicken Pox
Papular rash (vesicular)

rash in different stages

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