EXAM 4 Flashcards
what are mycobacterium
- bacteria found in food and water sources OR obligate parasites
- form capsules
- have a SLOW GROWTH RATE
why do mycobacteria have a slow growth rate
myolic acid in cell wall, has a long replication process
Mycobacterium tuberculosis (M. tuberculosis) transmission route
aerosols
pulmonary tuberculosis
- respiratory disease
- causes infection of macrophages, causing GRANULOMAS
- the cells in the center of the granuloma die, causing NECROSIS
ghon focus
primary infection site of pulmonary tuberculosis
ghon complex
ghon focus + lymph node infection
what are granulomas
an infected macrophage surrounded by foamy macrophages, lymphocytes, and fibrous mesh
progression of tuberculosis
- if bacteria is only initially controlled, can lead to latent tuberculosis
- can have lifelong containment OR reactivation to active TB
latent tuberculosis
- no active disease
- bacteria are encased in granuloma and don’t cause symptoms
- will test + for blood and skin tests
- will have normal x-rays and no symptoms
- RISK GROUPS: immunocompromised, elderly, young, diabetes
active tuberculosis
- occurs when a latent infection reactivates
- granulomas rupture and start infection
active tuberculosis symptoms
weight loss, loss of appetite, night sweats, fever, pulmonary symptoms
active tuberculosis treatment
long course drugs, untreated can be fatal
extrapulmonary tuberculosis
- infection outside the lungs, via bloodstream or lymph
- infection of pleura, CNS, lymphatic system, genitourinary system, bones and joints
milliary tuberculosis
- form of extrapulmonary tuberculosis
- characterized by TINY LESIONS, can infect other organs, high mortality
drug resistant tuberculosis
- due to failure to comply to long drug course
- MULTI-DRUG RESISTANT TB (MDR TB)
- EXTENSIVELY DRUG-RESISTANT TB (XDR TB)
TB prevention and screening
- tuberculin skin test (inspect for induration)
- bacillus calmette-guerin (BCG) vaccine
- DEPENDS ON GEOGRAPHIC REGION
Mycobacterium leprae (M. leprae)
- infects histiocytes and nerve cells
- low pathogenicity
- foot pads of armadillos
- “GENOME REDUCTION”: small genome size
Leprosy (Hansens Disease)
- neglected tropical disease
- granulomatous disease of peripheral nerves and mucosa of upper respiratory tract
- NUMBNESS IN EXTREMITIES, SKIN LEISONS, DISFIGUREMENT
leprosy pathogenesis
bacteria invades SCHWANN CELLS of peripheral nerves
leprosy transmission
person to person, inhalation of mucosal secretions, direct skin contact
tuberculoid (paucibacillary) leprosy
- TH1 mediated response
- localized or superficial infection
lepromatous (multibacillary) leprosy
- TH2 mediated response
- disfigurement, small hypo-pigmented lesions, numbness, weakness, peripheral nerve damage
leprosy risk factors
immunocompromised, malnutrition, exposure to leprosy
leprosy treatment
- multi drug therapy
- CURABLE
what are mycoplasma
- the smallest and simplest self-replicating bacteria
- “surface parasite”
- pleomorphic
- lacks a cell wall: TRILAMINAR MEMBRANE
- fastidious
- “fried egg colonies”
what is a trilaminar membrane
a plasma membrane containing sterols that are resistant to antibiotics
Mycoplasma pneumoniae (M. pneumoniae)
disease causes inflammation of the alveoli (lung), disease of respiratory epithelium
M. pneumoniae transmission
aerosols
M. pneumoniae infection route
attachment to P1 protein, binds sialic acid receptor causing cilia to not work
M. pneumoniae symptoms
- early: fever, headache sore throat
- late: primary atypical pneumonia “WALKING PNEUMONIA”, tracheobronchitis, blood-streaked septum, chest pain, ear aches
m. pneumoniae treatment
- broad spectrum antibiotics
- NOT PENICILLIN
m. penumoniae diagnosis
- serological tests (ELISA)
- cold agglutinins
mycoplasma hominis (M. hominis)
- cause of pelvic inflammatory disease, postpartum fever, vaginitis
- mycoplasma adheres to urogenital epithelium
- transmitted through sexual contact and newborns through birth canal
mycoplasma genitalium (m. genitalium) “mgen”
- cause of urethritis in men, cervicitis and pelvic inflammation in women
- sexually transmitted
- colonized the ciliated epithelial cells of urinary and genital tracts
- has a very small genome
what is m. gentialium useful for?
- minimal genome project
- synthetic genomes
minimal genome project
only essential genes that allow bacteria to grow and divide
synthetic genome
man-made DNA fragments, reassemble viable bacterial genomes
what are legionella
- gram negative pleomorphic bacilli
- REQUIRE CYSTINE to grow
- found in soil and aquatic environments
legionella pneumophila (L. pneumophila)
cause of legionnaires disease (primary atypical pneumonia)
transmission of L. pneumophila
water aerosols, amoebae, cooling towers/hot tubes/water tanks
NOT person to person
legionnaires disease symptoms
- early: mild bronchopneumonia, headache, weakness, muscle ache, dry cough
- late: fever, chest pain, stupor
- critical: multi-system disease
risk groups of legionnaires disease
middle aged/elderly, cigarette smokers, chronic lung disease, immunocompromised
diagnosis of legionnaires disease
antigen detection (ELISA on urine sample)
treatment of legionnaires disease
antibiotics
NOT PENICILLIN
flint michigan
legionnaires disease outbreak due to poor water safety plan
what are fungi
- eukaryotic organisms (have nucleus and mitochondria)
- have a phospholipid bilayer containing ERGOSTEROL
hyphae
long filaments that extend out to make up a network of fungi (mycellum)
septum
a cell wall that divide hyphae
polyene
- antifungal drug
- targets ergosterol resulting in pore formation and cell leakage
- amphotericin B
echinocandins
- antifungal drug
- disrupts cell wall synthesis that fungi use for intergrity
pyrimidine analogs
- antifungal drug
- blocks cytosine deaminase activity
- 5-florouracil VERY TOXIC
azoles
- antifungal drug
- disrupts unique ergosterol membrane surface and biosynthetic pathway
allylamines
- antifungal drug
- inhibits ergosterol biosynthesis
fungi reproduction
- can reproduce sexually or asexually
- sexual reproduction is important for the maintenance of pathogenicity
how are fungi classified
by the type of spore they make
chytridiomycota
chytrids
zygomycota
common molds
ascomycota
sac fungi
basidiomycota
club fungi
duteromycota
imperfect fungi
yeast cells
- type of colony morphology
- round or ovoid cells that produce daughters by budding
pseudohyphae
- type of colony morphology
- chains of elongated yeast cells, have indentations in the walls where cells meet
diversity of fungi
- there are more than a million species of fungi
- large diversity on the human skin
keratonlytic fungi
utilize keratin as a nutrient source
dermatophyte fungi
- kerationlytic
- causes ring worm
Tinea
- ringworm
- named for location on skin
pityriasis versicolor
- caused by MALASSEZIA SPP.
- commensal of the skin
- treated with an antifungal topical
Malassezia in the colon
- chrons disease
- patients with a risk allele for CARD9 have more malassezia in the colon
- hyperactive signaling due to serine12–>asparagine
onychomycosis
- fungal infection of the nails
- predisposing factors: tinea pedis, family history, male
opportunistic fungal infections
- the # of infections are increasing due to a new susceptible population of HIV/AIDs, transplant, and anti-TNF alpha monoclonal antibody therapy patients
Candida
- fungus that forms yeast-like cells
- part of the normal flora, colonize the GI and GU tract
candida albicans
most common cause of disease
candida auris
- emerging fungal pathogen
- multi-drug resistant
- causes systemic infections
muco-cutaneous candidiasis
- over growth of normal flora
- superficial infection (lining surfaces)
- can result from long term antibiotic use
disseminated candidiasis
- organism invades tissue and enters blood stream
- entry into blood is cause by leaky gut, catheters, immunocompromised, or physical breach
- non-specific sepsis
- antifungal prophylaxis, recent emergence of drug resistance
aspergillus
- mold
- multi use (pharmaceuticals and fermentation of soybean)
- have CONIDIA
- use polarized growth
what are conidia
- a vehicle for environmental dissemination, metabolically inactive, and resistant to multiple environmental stressors
- allows for deep penetration into human alveolar spaces
process of polarized growth
- hyphal extension occurs at the tip
- specalized organelles control hyphal growth (SPITZENKORPER AND POLARISOME)
- sterol-rich lipid rafts accumulate at the hyphal tip
- molecular motors bring vesicles containing necessary elements for cell wall synthesis and membrane synthesis
- much of the active endocytosis occurs at the hyphal tip
spitzenkorper
movement of vesicles
polarisome
coordinates endocytosis and exocytosis
what is the fundamental role of filamentous fungi
recycle environmental carbon and nirtogen
what fungi is predominant during the high temperate phases of composting
A. fumigatus
fungus ball/aspergilloma
- growth of A.fumigatus in airways without invasion
- can lead to bleeding
- can occur in healthy patients
allergic bronchopulmonary aspergillosis (ABPA)
colonization of the lung resulting in chronic inflammation and lung fibrosis
invasive aspergillosis
- can be relegated to the lung
- often disseminates hematogenously
- grows irrespective of anatomical boundaries
pathogenesis of invasive aspergillosis
- conidium invade alveolar mucosa
- if macrophages and neutrophils cannot take care of invasion, the fungi will escape and germinate
- fungi cross barrier of lungs to circulation
- fragments of fungi break in circulation and lodge in places rich in microvasculature (nutrients)
- once lodged, fungi pass endothelial barrier into tissue
cryptococcus neoformans
- basidiomycetous yeast-like fungus
- have a THICK POLYSACCHARIDE CAPSULE
- produce LACCASE
thick polysaccharide capsule components
- GXM (glucuronoxylomannan)
- GalXM (glactoxylomannan)
laccase
a multi-copper oxidase that is required for virulence
- produces melanin
titan cells
- in the lungs, c. neoformans can undergo a morphological change to a titan cell
- titan cells are polyploid and produce yeast cell progeny by reductive division
- progeny cells are more stress resistant
cryptococcosis
- portal of entry is lung, can cause begnin colonization to severe pneumonia (rapid dissemination to CNS in immunocompromised)
- MENINGOENCEPHALITIS
- dissemination can occur outside CNS, skin lesions, eye disease, organ systems
meningoencephalitis
- most common presentation of cryptococcosis
- headache, fever, ALTERED MENTAL STATE, fatal if untreated
thermal dimorphism
- filamentous (mould) @ 25°C (soil)
- yeast-like @ 37C (after inhalation)
blastomyces dermatitidis
extracellular yeast
upper midwest US
histoplasma capsulatum
intracellular yeast
Ohio and missisippi river valley
coccidioides immitis
extracellular spherioles
San Joquain valley of southwest US
commensalism
benefits one, neutral to the other
biological parasite
an organism that grows, feeds, and is sheltered on or in a host organism to the detriment of that host
medical parasite
organisms that cause disease in humans
- not bacteria, fungi or viruses
- endo (infection) or ecto (infestation)
definitive host
host in which the obligate sexual stage od a parasite life cycle occurs
intermediate host
host in which non-sexual reproduction or development occurs
incidental host
is not an obligate part of the parasite life cycle (zoonosis)
reservoir host
animal hosts that maintain the natural cycle in the wild
ingestive transmission
oral infection by a dormant cyst or egg in food or environment
protozoa cyst
an environmentally stable non-replicating form, typically involved in fecal/oral transmission
helminthes cyst
a dormant juvenile form typically embedded in host tissue; under-cooked meat
egg
the product of sexual reproduction by adult worms, contains a single embryonated prelarval form; fecal-oral
invasive transmission
direct penetration of the skin
vector transmission
transmission of an active non-replicating form by a blood0sucking arthropod
maternal transmission
trans-placental to a fetus in utero
biological vector
an essential host in the life cycle
phoretic vector
mechanical vector
geographic distribution
the maximum global extent of a disease regardless of intensity
prevalence
disease intensity in a given area
incidence
new infections in a susceptible population per unit of time
the chemotherapeutic problem
- we’re all eukaryotes
- how do you kill pathogenic organisms that utilize the same basic molecular pathways as every cell in the human body
trichomoniasis organism
Trichomonas vaginalis
trichomoniasis location
lumenal, urogenital
trichomoniasis lifecycle
no free living or encysted stages
trichomoniasis transmission
direct by sexual contact or RARE non-sexual contact
trichomoniasis epidemiology
cosmopolitan, SEXUALLY ACTIVE WOMEN globally 180 million/year; age 16-35
trichomoniasis prevention
safe sex, condoms
trichomoniasis pathology
- female: persistent vaginitis, itching and burning; inflammation of squamous epithelia; frothy discharge with skanky fishy
- male: asymptomatic, infection of urethra and prostate
trichomoniasis immunity
no immunity, reinfection possible
trichomoniasis diagnosis
microscopic observation
giardiasis organism
giardia lamblia
giardiasis location
lumenal, intestine
giardiasis transmission
ingestive, fecal/oral
giardiasis epidemiology
- cosmopolitan
- epidemic in daycares
- reservoir in wild animals
- anal
giardiasis prevention
good sanitation and personal hygiene
giardiasis pathology
- onset at 2 weeks
- explosive all of the sudden
- diarrhea, flatus, belching, cramps
- acute, can self cure
- malabsorption syndrome
giardiasis immunity
reinfection possible
giardiasis diagnosis
- stool examination, presence of cysts
- ELISA on stool
- immunofluorescence
-string test
amebiasis organism
entamoeba hystolytica
amebiasis location
lumenal
intestines —> tissues
amebiasis transmission
ingestive; fecal/oral
direct; anal
amebiasis epidemiology
- due to poor public sanitation
- poor hygiene, anal
amebiasis prevention
good sanitation, personal hygiene, condoms
amebiasis pathology
asymptomatic/mild –> dysentery –> invasive (hepatic)
amebiasis immunity
- humoral responses in invasive disease
- maybe acquired immunity in endemic cases
amebiasis diagnosis
- trophozoites and cysts in bloody stool
- aspirate of liver abscesses
- TRAVEL HISTORY
what are kinetoplastid protozoa
a group of flagellated protists that are characterized by the presence of an organelle with a large massed DNA called kinetoplast
leishmaniasis organism
leishmania (species) new world and old world
leishmaniasis location
blood and tissues
leishmaniasis transmission
vector-borne; sandfly
leishmaniasis reservoir
domestic and wild animals
leishmaniasis epidemiology
- tropical and subtropical
- contact with sandfly/reservoir habitat
leishmaniasis pathology cutaneous
- ulcerative sore at primary site
- abundant amastigotes in lesions
- spontaneous healing
leishmaniasis pathology mucocutaneous
- starts out like cutaneous
- metastasis months to years after primary lesion heals
- ulceration nasopharngeal tissues
- chemotherapeutic cure leads to immunity
leishmaniasis pathology visceral
- hematogenous spread to organs; primary lesions rare
- onset at 2-12 months, fever, wasting
- chemotherapeutic cure leads to immunity
leishmaniasis diagnosis
amastigotes in biopsies or aspirates
African Trypanosomiasis organism
trypanosoma brucei brucei
T. brucei rhodesiense
T. brucei gambiense
African Trypanosomiasis location
blood, lymphatics and tissues
African Trypanosomiasis transmission
vector-borne; tsetse fly
African Trypanosomiasis epidemiology
- sub saharan; endemic in tsetse habitat
- epidemic in areas of social turmoil
African Trypanosomiasis prevention
- vector avoidance, vector control
- monitor susceptible population, aggressive treatment
African Trypanosomiasis pathology
- early, middle, and late onsets
- self-healing chancre
- hematogenous dissemination
- waves of parasitemia with fever
- CNS infection
- death through coma or secondary infection
African Trypanosomiasis immunity
- initial humoral response leads to immunosupression
- immune evasion by antigenic variation
African Trypanosomiasis diagnosis
direct examination of blood, lymph, and CSF
winterbottoms sign
swollen cervical lymph nodes
south american Trypanosomiasis disease
chagas disease
south american Trypanosomiasis organsim
trypanosoma cruzi
south american Trypanosomiasis reservoir
rats, cats, dogs, opossums
south american Trypanosomiasis location
blood, lymphatics, tissues
south american Trypanosomiasis transmission
- vector borne; reduvid bugs
- the southern route
- transfusion, transplantation, IVDU
south american Trypanosomiasis epidemiology
- proximity to human waste
- intravenous drug use
south american Trypanosomiasis prevention
vector control; good housing; screen blood supply
south american Trypanosomiasis pathology
- acute: chagoma (Romana’s sign); hematogenous spread, circulating trypomastigotes; severe in children
- chronic: onset after 10-20 years; damage to never/muscle cells of heart, esophagus, colon; inflammation leads to tissue damage; death from sudden heart attack
south american Trypanosomiasis acute diagnosis
trypomastigotes in blood
south american Trypanosomiasis chronic diagnosis
xenodiagnosis
anticomplexan parasites
- obligate intracellular parasites
- sexual and asexual reproduction
- sexual cycle in the intestinal epithelial of definitive hosts
toxoplasmosis organism
tosoplasma gondii
toxoplasmosis location
tissue/blood
toxoplasmosis reservoir
cats, sheep, mice
toxoplasmosis transmission
ingestive: fecal/oral and undercooked meat
TRANSPLANCENTAL: congenital infection
toxoplasmosis epidemiology
- cosmopolitan and world-wide
- developed world: undercooked meat and litter box
- developing world: public hygiene, cats, climate
- congenital infection: only with primary maternal infection
- reactivation of latent infection in immunocompromised
toxoplasmosis prevention
avoidance behavior by at risk population
what are the 2 phases of toxoplasma infection
- tachyozoite
- bradyzoite
tachyzoite
- rapid replicative form during initial acute infection
- generated by reactivation of dormant cysts
- can cross placenta, causes encephalitis in AIDS
- control by primary immune response
bradyzoite
- encysted slow growing form during dormant phase
- source of reactivation throughout life-long infection
- control by memory immune response
toxoplasmosis pathology
- initial infection asymptomatic
- rapid control by humoral and cellular immunity
- life long latent infection
- immunodeficient cannot control initial infection
- in utero infection causes severe consequences
toxoplasmosis diagnosis
- serology
- IFA
- seizure in AIDs
malaria organism
- multiple of plasmodium species
- P. falciparum is most deadly
malaria location
hepatocytes/erythrocytes
malaria reservoir
humans
malaria transmission
- vector borne: female misquitoes
- also congenital and needle transfer
malaria epidemiology
- cosmopolitan: 2 billion at risk
- most fatalities in children
- increased drug and insecticide resistance
- most morbidity and mortality due to P. falciparum
malaria pathology
- fever cycle with synchronous bursts of merozoites
- anemia from erythrocyte destruction
- chills, fever, splenomegaly, myalgia, headache
- cerebral malaria (P. FALCIPARUM ONLY)
- latent hepatic forms in P. vivax and P. ovale
malaria diagnosis
- gemisa stain of blood smears
- P. FALCIPARUM: multiple rings per RBC, no circulating trophozoites or schizonts, banana shaped gametocytes
malaria immunity
- slow to develop, requires multiple infections
- short lived
- easily reinfected
malaria prevention
- drugs to resist infection
- avoid mosquitoes when feeding
class cestoda
- tape worms
- no internal digestive system
- attach to gut wall of definitive host (humans)
- segments mature from anterior to posterior
- transmission by ingestion of larval cysticerci or eggs
class trematoda
- flukes of the lungs, liver, and blood
- broad flattened bodies with a simple digestive system: single opening
- one or more intermediate host (snail)
- transmission can be invasive or ingestive
class nematoda
- roundworms of tissues and gut
- cylindrical bodies: well developed digestive and nervous system
- transmission: ingestive, invasive, or vector-borne
beef tapeworm organism
taenia saginata
beef tapeworm location
lumenal, jejunum
beef tapeworm transmission
eating undercooked beef containing cysticerci
beef tapeworm definitive host and intermediate host
- humans
- cattle
beef tapeworm life cycle
the “basic” cestode cycle
beef tapeworm epidemiology
world-wide and cosmopolitan in beef eating countries
beef tapeworm pathology
abdominal discomfort; rarely serious, occasional weight loss
beef tapeworm immunity
- humoral response
- reinfection possible
beef tapeworm diagnosis
active worms in stool
beef tapeworm prevention
good public hygiene, well cooked beef, freezing
pork tapeworm organism
taenia solium
pork tapeworm location
lumena, jejunum, any tissue (cysticerci)
pork tapeworm definitive and intermediate host
- humans
- pigs or human
pork tapeworm transmission
- if ingest cysticerci: definitive host (bad)
- if ingest eggs: intermediate host (very bad)
pork tapeworm life cycle
cysticerci cycle, EGGS ARE INFECTIOUS TO HUMANS
pork tapeworm pathology
- same as beef tapeworm
- NEUROCYSTICERCOSIS: brain lesions, neurological disorders, mortality
pork tapeworm diagnosis
- active worms in stool
- x-ray
- CAT/MRI
pork tapeworm prevention
- well-cooked pork
- freezing
- good public hygiene
pinworm organsim
enterobius vermicularis
pinworm location
adults in colon
pinworm transmission
ingestion of eggs
pinworm host
humans
pinworm epidemiology
- cosmopolitan
- equal opportunity parasite
- daycare centers
pinworm pathology
- intense perianal pruritis
- secondary infection due to scratching
- rare urogenital invasion in females
pinworm immunity
none, reinfection possible
pinworm diagnosis
- persistant perianal itch
- insomina
- observation of eggs