Microbiology Diseases due to Fungi and associated Characteristics/Clinical Presentation

8/13/2019 Microbiology Diseases due to Fungi and associated Characteristics/Clinical Presentation

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Disease Agent Characteristics / Virulence Clinical Presentation Diagnosiscutaneous: a) oral thrush: whitish lesion,

b) vaginal, c) dermatitis, d)

onychomycosis: invasion of nail plates, e)

diaper rash

systemic(catheters, IV drug use):

transient (immunocompetent),

infections anywhere

(immunocompromised)

chronic mucocutaneous: skin and

mucous membranes, rare, childhood,

immunodeficiencies

Cryptococcosis Cryptococcus sp.budding, encapsulatedcells, diphenol oxidase

(forms melanin), grow @37C (only one that can)

pulmonary: asymptomatic / flu-like;

disseminated: yeast prefers CSF

(meningitis), skin lesions, cryptococcoma

bird seed agar(contains

diphenol oxidase); india ink

(capsule); serology: detection

of capsule antigen in CSF via

LAT

Allergic aspergillosis (asthma)

Aspergilloma / extrapulmonary:

aspergilloma (lungs), otomycosis,onychomycosis, eye infection

Invasive aspergillosis (fatal): pulmonary

and disseminated

Mycotoxicosis: aflatoxin production (A.

flavus most severe)

Pneumocystis

pneumoniae

Pneumocystis

jiroveci

extracellular pathogen: a) thin-walled

trophozites, b) cysts(infectious)

Sx: fever, SOB, wt. los,night sweats, non

productive cough; interstital fibrosis of

lung w/ thickened alveoli -> hypoxia

CXR: infiltrates; can NOT be

cultured; toluene blue stain

(cysts), PCR no definitive

primary/pulmonary: self-limited flu-like

symptoms, diffuse pneumonia

extrapulmonary: cutaneous, bones,

meningesdisseminated: immunodeficient or

pregnant (estradiol, progesterone),

chorioretinitis, racial succeptability as

well

erythema nodosum: allergic response

(type IV), good prognosis (CMI)

HistoplasmosisHistoplasma

capsulatum

yeast: blastoconidia; mold: dimorphic

a)tuberculate macroconidia, b) microcondia;

histoplasmin antigen (broth); urease (raise pH -

neutralize l sosome

inhaled microconidia -> convert to yeast -

> flu-like symptoms -> RES (intracellular

mycosis) -> granulomatous foci (miliary)

Location, intracellular yeast,

LAT

BlastomycosisBlastomyces

dermatitidis

thermally dimorphic;broad based multinucleate

budding; chlamydospores possible

inhaled microconidia soil --> flu-like ->

non-caseating granulomas (can be

extrapulmonary/cutaneous)

wet mount KOH: broadly

attached buds on thick walled

cells

Candidiasis Candida sp.

budding yeast, pseudohyphae, true hypha

(serum), chlamydospores (nutritionally deficient

media), protease, phospholipase, Hsp's, biofilms,

Alibicans and dubliniensis form germ tube

chrome agar differentiates

Candida, no sputum samples

(normal flora); direct exam:

gram +, 10% KOH; culture (look

for hyphae, pseudohyphae, andgerm tubes); serology: LAT,

ELISA

Valley FeverCoccidioides

immitis

dimorphic (in pt: sporangiospore; in culture:

arthroconidia); spherule w/endospores; soil,

powdery; "empty cells" are the distinguishing

feature, hyphae fragment easily;arthrospore is

inhaled; aerobic (dust storms)

culture: Sabouraud's agar

(arthroconidia); sputum: KOH;

bx: PASstain; blood: IgG/IgM

to coccidioidin or spherulin

Aspergil losis Aspergil lus sp.powdery mold (aerosolize); true hyphae (hyaline,

septate); microconidia;phospholipase

serum IgE, Direct exam:septate hyphae, conidia,

intravascular hyphae, SDA

culture, ELISA: galaktomannan

antigen


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Disease Agent Characteristics / Virulence Clinical Presentation Diagnosis

Paracoccidio-

idomycosis

Paracoccidioides

brasiliensisyeast: multiple buds

pneumo, self-limited granulomatous

disease (can disseminate)

KOH prep (multiple buds); skin

test

Streptococcus

mutans

lactic acid fermentation (decreases pH),

glucosyltransferase (sucrose -> glucan)initiator of dental caries

Lactobacillus sp. lactic acid fermentation, grows @ low pH progression of caries

Actinomyces

viscosuscatalase+ implicated in root surface caries

Veillonella sp.anaerobic, converts lactic acid to weaker acids (^

pH)possible anticariogenic role

Chronic

Gingivitis

55% gram+ facultative organisms; actinomyces

(+), capnocytophaga (-)

inflammatory response limited to gingiva

- no bone or periodontal pockets

red & swollen gingivae,

bleeding gums, halitosis

Periodontitisincrease in anaerobic organisms; prphyromonas

gingivalis and prevotella intermedia (both -)

progression of gingivitis that involves

connective tissue & bone

Porphyromonas

gingivalis (NF)

gram - coccobacilli, obligate anaerobe, fimbrae,

HG, hemolysins, proteases, capsule

black on blood agar (hemin

required)Prevotella

intermedia &

Tanerella

forsynthia

gram - short bacilli, obligate anaerobes; 95% of

peridontal disease; saccharolyticbrown-black on blood agar

Capnocytophaga

(NF)gram - bacillus (fusiform); capnophilic

Aggressive

periodontitis

Actinobacillus /

Aggregatabactergram -, capnophilic, tetracyline sensative

begins on incisors / 1st molars (local or

generalized); bone loss c no bleeding,

inflammation, or plaque

Fusobacterium

nucleatum

gram - cigar shaped bacillus; obligate anaerobe;

NF, adhesins, endotoxin

Treponema sp. oral spirochete, motile, gram-; obligate anaerobe

Noma

(Gangrenous

Stomatitis,

Cancrum Oris)

same as ANUGsevere ANUG; young children in

developing countriestissue loss & disfigurement

Dentoalveolar

Abscess

Prevotella,

Porphyromonas,

Fusobacterium

spread to soft tissue or bone or to lymphatics and

bloodstreamextension of a carioius lesion

Lugwig's Angina Polymicrobial post extraction infectionswelling at the front of the neck (airway

obstruction), fever

Periodontal

Abscesspolymicrobial localized infection; tooth loss w/o treatment

red, swollen, & tender gingivae overlying

abscess; painful

Cervicofacialactinomycosis

Actinomycesisraelii

gram + anaerobe; infection from endogenousflora,

submandibular region swelling (lumpy

jaw); fibrosis; gritty/sand-like pus c

yellow granules

"sulfur granules" (pus); "molartooth" appearance (culture)

Oral Thrush yeast cells c pseudohyphae (invasive)pseudomembrane; "cottage cheese

curds"Candida-

associated

Denture

Stomatitis

non-invasive; plaque biofilmserythema & edema of mucosa in contact

w/ surface of upper denture

Dental Caries

Chronic

periodontitis

Acute

Necrotizing

Ulcerative

Gingivitis(ANUG) -

"Trench Mouth"

red inflamed shiny bleeding painful

gums, covered by pseudomembrane,

metallic taste; painful

3 components: fusobacteria,

spirochetes, leukocytes

gingival lesion + gingival recession &

bleeding pockets, NO PAIN; G+ near

tooth, G- near gingival crest

Candida albicans;

opportunistic

clinical presentation; germ tube

test


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HSV-1 (oral and

genital)

HSV-2 (oral and

genital)

Herpanginafever, sore throat c pain, ulcerations on

soft palate

Hand-foot-

mouth disease

vesicular lesions on hands, feet, mouth,

tounge, low grade fever

Aspetic

meningitis

Rotavirus

dsRNA segmented genome; non-enveloped;

NSP4 (enterotoxin: mobilizes Ca from ER, Cl-

secretion enhanced -> loss of water from cells,

reversible)

ELISA: stool; LAT; Vaccines:

Rotashield (removed from

market - critisized) Rotarix

(monovalent LAV for GI),

RotaTeq (live oral

reassortment)

Enteric Adenovirus dsDNA; acid-resistant capsule immunoassay

Calicivirus sapporo-l ike virus; ssRNA non-enveloped

Norovirus "Norwalk"; ssRNA non-enveloped

Astrovirus ssRNA star-shaped capsid EM

Coronavirus

Coxsackie A Virus

Vibrio cholerae

gram- vibrio, facultative anaerobe, motile,

oxidase+, O antigens (O-1 [El Tor], O-139);

virulence: a) cholera toxin (AB) increases cAMP

(causes hypersecretion of water and

electrolytes), b) toxin coregulated pilus (VP1)for

attachment; CTXbinding to VPI cel causes release

of toxin (2 lysogenic conversions needed

acute massive (1L/hr) watery diarrhea

("rice water" stool); "washwoman

hands", weak pulse -> hypovolemic

shock, metabolic acidosis -> death

direct exam; culture: yellow on

TCBS agar - alkaline, salt;

oxidase+; serology; Strains of O-

1 can sause diarrheal disease

but not cholera (lack cholera

toxin)

Vibrio

parahaemolyticus

mild cholera-like illness; 2-3 days watery

diarrhea; can get in via wounds

oxidase+; green on TCBS, no

sucrose fermentation

Vibrio vulnificus emerging pathogen

a) wound infections; b) sepsis

(underlying liver disease -> Fe) ->

bullous skin lesions

green on TCBS

Reiter's syndrome: non-specific acute

inflammatory arthritis

Hemolytic uremic syndrome (HUS): type1 infection, acute renal failure, poor

prognosis, provoked by Ab therapy

S. enterica

(species) includes:

Herpes Simplex

fever blisters / cold sores; persistent

infections in neurons; lytic infections in

epithelium & fibroblasts;

gingivostomatitis seen in children;

pharyngotonsillitis, herpetic whitlow

clinical lesions,tzanck smear -

multinucleated giant cells,

Cowdry type A inclusions

Coxsackie A Virus

ssRNA+, non-enveloped; path: lymphoid tissues /

mucosa -> primary viremia -> skin/mucous

membranes (symptoms); enterovirus

clinical presentation; culture

no good tests

linear dsDNA, enveloped, path: primary infection

(mucoepithelial cells) -> syncitia & intranuclear

inclusions bodies -> neuron (retrograde to

trigeminal ganglion)

Cholera

Shigella sp.

gram - facultative intracellular bacilli;lactose non-

fermenter; virulence: enterotoxins, O antigen

(lyses phagosome and escapes to cytoplasm),actin binding protein (steals host actin), shiga

toxin - disrupts protein synthesis, not confined to

GI

Suspect with fever and diarrhea

(blood mucus acute), fecal

exam: PMNs & RBCs present;culture: fast (w flecks of blood-

tinged mucous) on SS agar

(white); sigmoidoscopic exam

Viral

Gastroenteritis:

non-invasive acute watery diarrhea;

dehydration

Autoimmune disease: pasmid encoded

antigen reacts c host myosin

Shigellosis

gram - rod, facultative anaerobe, lactose non-

fecal exam: macrophages >


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S. typhi (typhoid

fever)

S. typhimurium

(food poisoning)

S. enteritidis (food

poisoning)

Salmonellosis

,

invasion genes (A-H), LPS, acid resistance, phoPQ-

controlled genes (phagocyte survival) **Unlike

shigella it can enter M and epithelial cells

,

septicemia, c) enteric fever, d) carrier

state

PMNs; culture: SS agar (white) -

food, water, feces, blood;

serology

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Microbiology Diseases due to Fungi and associated Characteristics/Clinical Presentation