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466 Cards in this Set

  • Front
  • Back
Microorganisms associated with birds - Fungi, Bacteria, Viruses
Fungi:
histo (also with bats)
Crypto (pigeons)
Bacteria:
Chlamydia psittaci (parrots, etc)
Viruses:
H5N1 - Avian influenzae
West Nile Virus
Characteristics/mechanism of infection: Giardia lamblia
owl eyes, four pairs flagella
MC protozoan infection in US. adheres to mucosa, secretes molecules that induce mucosal inflammatory response
Sx: Giardia lamblia
Infects whom?
bloating, flatulence, foul-smelling diarrhea, campers/hikers
Transmission: Giardia lamblia
Transmission - cysts in water (beaver fever)
Dx: Giardia lamblia
Dx: Trophozoites/cysts in stool
Tx: Giardia lamblia
Metronidazole (GET GAP on the Metro)
Characteristics: Trichomonas vaginalis
triangular, flagellated
Sx/Dx: Trichomonas vaginalis
vaginitis - foul-smelling, greenish discharge, itching and burning.
Strawberry cervix
Causes alkaline pH
Trophozoites (motile) on wet mount
Transmission: Trichomonas vaginalis
sexual
Tx: Trichomonas vaginalis
metronidazole (GET GAP on the Metro)
Sx: Trypanosoma cruzi
Chagas' dz. Dilated cardiomyopathy, megacolon, megaesophagus, achalasia, swelling of eye (Romana's sign). 'Makes everything bigger'
Predominantly S. America
Transmission: Trypanosoma cruzi
Reduviid bug (kissing bug). Found in thatched roofs of huts
Dx: Trypanosoma cruzi
Blood smear
Tx: Trypanosoma cruzi
Nifurtimox
Characteristics/Sx: Trypanosoma brucei - gambiense and rhodesiense
west and east African sleeping sickness (slow and fast onset, respectively), enlarged lymph nodes, recurring fever (due to Ag variation), somnolence, coma
Transmission: Sleeping sickness
Tsetse fly
Dx: Sleeping sickness
Blood smear
Tx: Sleeping Sickness
Blood-borne - SURamin + pentamidine
CNS penetration - MELArsoprol
'It SURe is nice to get sleep. MELAtonin helps with sleep'
Sx: Leishmania donovani
Visceral Leishmaniasis (kala-azar) - spiking fevers, HS-megaly, pancytopenia

Cutaneous Leishmaniasis - big pustules on skin
Transmission: Leishmania donovani
Sandfly
Reservoir = dogs
Dx: Leishmaniasis
Macrophages containing amastigotes
Tx: Leishmaniasis
Sodium stibogluconate
Life cycle: Plasmodia
Sporozoite --> early/late schizonts --> merozoite

Sporozoite - acquired from anopheles mosquito.
Early/late - Reproduce intracellularly (hepatocytes + RBCs)
Merozoites - cause cell lysis

Trophozoites in RBCs look like diamond ring.

Falciparum - also has cresent-shaped gametocytes in blood
Sx: Plasmodia
Unique characteristics of each?
Which are MC?
Which lead to relapsing Malaria?
Malaria - cyclic fever (response to merozoites that rupture out of RBCs), headache, anemia, splenomegaly
Falciparum - severe cerebral malaria
P. vivax and P. ovale have dominant forms in liver (hypnozoites) that lead to relapsing malaria
Vivax and falciparum are MC forms
Tx: Malaria (4 options)
First choice
1: Chloroquine + primaquine - prevents relapse of vivax/ovale. Also used as prophylaxis
If resistant:
2: sulfadoxine + pyrimethamine
3: mefloquine (alone)
4: quinine (not approved for restless leg syndrome) + doxycycline
Ixodes tick is involved in the transmission of...
Babesia and Borrelia burgdorferi (lyme)
Characteristics: Babesia
Ixodes carrier, maltese cross and ring forms, NE USA
Sx: Babesiosis
Fever, hemolytic anemia
Dx: Babesiosis
Blood smear, no RBC pigment, Maltese cross
Tx: Babesiosis
Quinine
Clindamycin
Cryptosporidium is especially dangerous in whom?
AIDS patients - causes severe diarrhea. Mild, watery diarrhea in non-IC
Transmission/Dx/Tx: Cryptosporidium
Transmission: Cysts in water
Dx: Cysts on acid-fast stain
Tx: none needed
Characteristics: Toxoplasma gondii
crescent-shaped, T in ToRCHeS
Toxoplasma transmission in utero, manifestations (Classic triad)
Via placenta. 'classic triad' = chorioretinitis, intracranial calcifications, hydrocephalus. May be asymptomatic at birth.
Pregnant women should avoid cats, not change cat litter.
ToRCHeS
What else is transmitted via placenta or birth canal?
transmitted in utero or during vaginal birth:
Toxoplasma gondii
Rubella
CMV
HIV
Herpes virus 2
Syphilis

Also, Listeria, E. coli and GBS can be acquired placentally or from birth canal, as can GC and Chlamydia
Transmission: Toxoplasma gondii
Cysts in raw meat (e.g. stake tartar) or cat feces. Pregnant women should avoid cats, not change cat litter.
Sx: Toxoplasma gondii
Brain abscess (which would cause ring-enhancing lesions) or brain lesions in HIV pts.
Tx: Toxoplasma gondii
Sulfadiazine + pyrimethamine
Sx: Entamoeba histolytica
What bacterium has similar organ effects?
Amebiasis: bloody diarrhea (dysentery), liver abscess (leptospira also affects liver), RUQ pain
Transmission: Entamoeba histolytica
Cysts in water
Dx: Entamoeba histolytica
Ingested RBCs in cytoplasm of entamoeba
Serology
Trophozoites/cysts in stool
Tx: Entamoeba histolytica
Iodoquinol and metronidazole
GET GAP on the Metro
Dysentery
Amebic - Entamoeba histolytica
Bacterial - Shigella

Both have watery diarrhea for few days, followed by severe, potentially life-threatening, potentially bloody diarrhea
Sx: Naegleria fowleri
Rapidly fatal meningoencephalitis
Transmission: Naegleria fowleri
Swimming in freshwater lakes - enter via cribriform plate
Dx: Naegleria fowleri
Amoebas in CSF
Nematodes and their routes of infection
EAT SANd

-Ingested-
Enterobius
Ascaris
Trichinella

-Cutaneous (feet)-
Strongyloides
Ancylostoma
Necator

Get these from not wearing SHoes: Strongyloides, Hookworms (Ancylostoma/Necator)
Enterobius vermicularis
Pinworm (little white worms)
Food contaminated with eggs (Eat sand)
intestinal infection, anal pruritis. Scotch tape test
MC helminth in US children
Helminth that causes Eosinophilic pneumonitis (Loeffler's Syndrome)
Ascaris Lumbricoides (giant roundworm)
Eat eggs --> intestinal infection/invasion --> blood --> ALVEOLI --> cough up --> swallow --> excrete in feces
Ascaris Lumbricoides
Giant roundworm
Eat eggs --> intestinal infection/invasion --> blood --> ALVEOLI --> cough up --> swallow --> excrete in feces
Causes eosinophilic pneumonitis
Eggs visible in feces
1/3 of world infected
Tx: Enterobius vermicularis (pinworm) or Ascaris lumbricoides (giant roundworm) or Ancylostoma duodenale or Necator americanus (hookworms)
Mebendazole (Worms BEND) or pyrantel pamoate

same for all
Trichinella spiralis
undercooked meat, usually pork; inflammation of muscle (larvae encyst in muscle), periorbital edema
Tx: Trichinella spiralis
Thiabendazole
Strongyloides stercoralis
Larvae penetrate SKIN of feet --> blood --> alveoli --> cough, swallow --> intestinal infection
Causes vomiting, diarrhea, anemia
Tx: Strongyloides stercoralis
Ivermectin
Thiabendazole
Ancylostoma duodenale, Necator americanus (hookworms)
larvae penetrate skin of feet --> intestinal infection --> possibly anemia (suck blood through intestinal walls)
One of MCC of IDA worldwide
Nematodes (roundworms)
Include enterobius, ascaris, trichinella, strongyloides, ancylostoma
Cestodes (tapeworms)
Include Taenia, Dipyllobothrium, Echinococcus
Trematodes (flukes)
Egs. and Tx
Include Schistosoma, Clonorchis, Paragonimus
All treated with Praziquantel
Taenia solium
Ingestion of encysted larvae from undercooked pork

Egg ingestion --> cysticercosis (larvael form in muscles --> myositis) or neurocystiscercosis (mass lesions in brain, swiss cheese appearance, seizures)
Tx: Taenia solium
Intestinal worms/cysticercosis?
Neurocysticercosis?
Cysticercosis - Praziquantel
Neurocysticercosis - Albendazole
Diphyllobothrium latum
larvae in freshwater fish
Causes B12 deficiency, resulting in megaloblastic anemia
Tx: Diphyllobothrium latum
Praziquantel
Echinococcus granulosus
Eggs in dog feces (also found in sheep. Both animals in tapeworm life cycle) - ingested - cysts in liver. Causes anaphylaxis if Ags released from cysts
Tx: Echinococcus granulosus
Albendazole
Schistosoma
Hosts/transmission/Dz/course
Hosts: Freshwater snails
Penetrate skin
Cause granulomas, fibrosis, Inflammation of spleen (Splenomegaly), liver (Portal HTN)
Swimmer's itch - starts 24 hrs after infection, lasts week

Hematuria - #1 in DDx of 3rd world pt. with hematuria
Schistosoma haemotobium
can lead to squamous cell carcinoma of the bladder (MC predisposing factor in 3rd world)
Schistosoma mansoni epidemiology
seen in Caribbean/PR
Tx: Schistosomes
Praziquantel (as with all Trematodes - flukes)
Clonorchis sinensis
undercooked fish, causes inflammation of biliary tract --> pigmented gallstones. Associated with cholangiocarcinoma
Tx: Pediculosis capitis/pediculosis pubis
lice - malathion, pyrethrin, permethrine
crabs - pyrimethamine, pyrethrin, malathion

Lindane not first line because of neurotoxicity
Tx: Roundworms
Go with a BEND drug
Brain cysts, seizures (helminth)
Taenia solium
Liver cysts (helminth)
Echinococcus granulosa
B12 deficiency (helminth)
Diphyllobothrium latum
Biliary tract dz. (helminth)
Clonorchis sinensis
Helminth that causes Hemoptysis
Paragonimus westermani (undercooked crab meat, causes inflammation and secondary bacterial infection of lung)
Portal HTN (helminth)
Schistosoma mansoni
Hematuria, bladder cancer (helminth)
Schistosoma haematobium (3rd world)
Microcytic anemia (helminths)
Ancylostoma, Necator
Perianal pruritis (helminths)
Enterobius
Scotch tape test
Enterobius
Eosinophilic pneumonitis
Ascaris lumbricoides
Myositis, periorbital edema (helminth)
Trichinella spiralis
Can't break cysts or will cause anaphylaxis
Echinococcus granulosus
Eggs from dog feces
Echinococcus granulosus
Snails are host
Schistosoma
Splenomegaly and Portal HTN (helminth)
Schistosoma
Undercooked fish (helminths)
And diseases
Clonorchis sinensis (biliary tract, cholangiocarcinoma)
Diphyllobothrium latum (B12 deficiency)
Biliary tract inflammation, pigmented gallstones, cholangiocarcinoma association
Clonorchis sinensis
Gram+ve
Cocci
Catalase+
Coagulase+
Staph aureus
Gram+ve
Cocci
Catalase+
Coagulase-
Novobiocin sensitive
Staph epidermidis
Gram+ve
Cocci
Catalase+
Coagulase-
Novobiocin resistant
Staph saprophyticus
Gram+ve
Cocci
Catalase-
No hemolysis
Enterococcus (E. faecalis)
Peptostreptococcus (anaerobe)
Gram+ve
Cocci
Catalase-
alpha (partial - green) hemolysis
+ Quellung
Optochin sensitive, bile soluble
diplococci
Strep pneumonia
Gram+ve
Cocci
Catalase-
alpha (partial - green) hemolysis
- Quellung
Optochin resistant bile insoluble
-Quellung = No capsule
Viridans strep
e.g. Strep mutans
Gram+ve
Cocci
Catalase-
beta (complete - clear) hemolysis
Bacitracin sensitive
GABHS Pyogenes
Gram+ve
Cocci
Catalase-
beta (complete - clear) hemolysis
Bacitracin resistant
GBS B for Babies
Strep agalactiae
Gram+ve
Rods
Spore-forming
Clostridium (anaerobe), Bacillus

Corynebacterium
Listeria
Gram+ve
Branching filaments
Nocardia
Actinomyces
S. aureus virulence factor
Protein A
binds Fc-IgG, inhibiting complement/opsonization/phagocytosis
TSST
superantigen in S. aureus
Binds MHC II and T-cell receptor --> polyclonal T-cell activation.

Toxin-mediated disease - ingestion of preformed toxins leads to rapid on/off food poisoning (enterotoxins - e.g. mayo that's been sitting out).

Also toxin-mediated: scalded skin syndrome
Inflammatory disease - skin infections, organ abscesses, pneumonia
(bacterial)
S. aureus
Acute bacterial endocarditis, osteomyelitis (bacterial)
S. aureus (salmonella in SCD pts)
MRSA resistance
altered penicillin binding protein
Staph epidermidis
Infects prosthetic devices and catheters (insertion can cause bacteremia). Cause of endocarditis (in-dwelling catheter). Contaminates cultures
Strep pneumoniae
Strep pneumoniae is Most OPtochin Sensitive. MCC of:
Meningitis
Otitis media (children)
Pneumonia
Sinusitis
Encapsulated bacterium, IgA protease
Strep pneumonia - this is why it infects airways. capsule is primary virulence factor
Subacute endocarditis
Strep viridans, Strep epidermiditis, Enterococci
Mastitis
Staph aureus - continued milk movement necessary to clear infection - not harmful to baby
Rusty sputum
Strep pneumonia
Sepsis in SCD/splenectomy pts.
Strep pneumonia
Normal flora of mouth.
E.g. that cause dental caries.
E.g. that cause endocarditis (when...)
Strep viridans. Sanguis - causes endocarditis (if turbulent heart flow problem exists - requires prophylaxis). Mutans - dental caries.
Protein in S. pyogenes that causes autoimmune problems
M Protein (helps evade immune response)--> rheumatic fever
Detection of recent strep pyogenes infection
ASO titer detects recent strep pyogenes infection
Strep Pyogenes infections
Pyogenic - pharyngitis (don't have to treat in adults), cellulitis, impetigo
Toxigenic - scarlet fever, TSS
Immunologic - rheumatic fever, acute glomerulonepritis

Subcutaneous nodules
Polyarthritis
Erythema marginatum
Chorea (Sydenham's)
Carditis
Able to hide within blood clots before re-emerging and infecting
S. aureus
Cause skin infections: folliculitis, cellulitis, impetigo
S. aureus
S. pyogenes
Exotoxins - S. aureus
alpha toxin - hemolysis
beta toxin - sphingomyelinase
Proteins A, B and C of gamma toxin - hemolysin and leukocidin
These give it ability to hide within blood clots, hiding from immune system before re-emerging and infecting
Enterotoxins A-E - food poisoning
TSST-1 - TSS (fever, rash, shock)
Epidormolytic/exfoliative toxins - Scalded skin syndrome
Toxins - S. pyogenes
Streptolysin O/S - hemolysis
Erythrogenic/Pyrogenic - Skin rash (sandpaper-like)/fever of scarlet fever
Diptheria toxin
Similar to? Does what?
Inactivates EF-2
Lethal - interferes with protein synthesis in heart/nerve cells
Similar to Pseudomonas exotoxin A
Vibrio cholerae exotoxin
ADP ribosylation of Gs --> stimulates adenylyl cyclase --> increased pumping of Cl into gut, decreased Na absorption. Water follows.
cAMP inducing toxins
Cholera (E. coli labile toxin pretty much same thing) turns the 'on' on (Gs)
Anthrax toxins includes edema factor, a bacterial adenylate cyclase, as is Pertussis toxin --> increased cAMP

(note: cholera, E. coli ADP ribosylate to increase cAMP, while anthrax edema factor and pertussis toxins are adenylate cyclases)
Clostridium perfringens toxin
alpha toxin
gas gangrene
double zone of hemolysis on blood agar
C. tetani toxin
blocks release of GABA and gly
C. botulinum toxin
blocks Ach release, causing anticholinergic Sx (dry as a bone, hot as a hare...), CNS paralysis. Can't give honey to <1yr baby.
Shiga toxin
also produced by O157:H7
cleaves host cell rRNA (inactivates 60S ribosome)
Enhances cytokine release, causing HUS
O157:H7 toxin is like which other toxin? What does it do?
Same as shiga toxin
cleaves host cell rRNA (inactivates 60S ribosome)
Enhances cytokine release, causing HUS
E. coli Heat Labile/Stable toxin
Labile/Stable - stimulate Adenylate/Guanylate cyclase, both causing watery diarrhea.
Labile like Air, stable like Ground
Pertussis toxin
Increases cAMP b/c toxin is an adenylate cyclase, causes whooping cough. Inhibits chemokine receptor, causing lymphocytosis
Bacteria that secrete enterotoxins
Staph aureus, E. coli, Vibrio cholerae, Salmonella/Shigella
Obligate intracellular bacteria
Rickettsiae, Chlamydia - can't make own ATP
'stay inside because it is Really Cold'

Legionella also hard to stain because often inside cells.
Gram stain limitations
Treponema (too thin - dark field, fluorescent Ab)
Ricketssia (intracellular)
Mycobacteria (high-lipid content cell wall - acid fast stain - mycolic acid)
Mycoplasma - no cell wall
Legionella (primarily intracellular - silver stain)
Chlamydia (intracellular - lacks muramic acid in cell wall)
Giemsa stain
Borrelia, Plasmodium, trypanosomes, Chlamydia
PAS (periodic acid-Schiff)
stains glycogen, mucopolysaccharides, used to Dx Whipple's dz.
Ziehl-Neelson
Acid-fast bacteria
India ink
Cryptococcus
Silver stain
Fungi, Legionella, Pneumocystis
Chocolate agar w/ factors V (NAD) and X (hematin)
H. influenzae
Thayer-Martin media
N. gonorrhoeae
Lowenstein's-Jensen agar
M. tb - takes 2 weeks. Do acid-fast stain and start treating
Eaton's agar
M. pneumoniae
Pink Colonies on MacConkey's agar
Lactose-fermenting enterics.
Has bile salts, crystal violet to inhibit gram+ves. Lactose + neutral red taken up --> pink. If don't take up lactose, white colonies.
Pigment producing bacteria
S. aureus - yellow
Pseudomonas - blue-green
Serratia marcescens - red (maraschino cherries)
IgA protease in bacteria
S. pneumoniae, H. influenzae, Neisseria
All these cause meningitis
Give Pneumovax to all pts. >65, asplenic, resp. dz. (e.g. asthma), HIV+
IgA protease cleaves IgA dimer, allowing mucosal binding and penetration
Endotoxin
Gram-ve cell wall comonent - LPS. heat stable
Lipid A especially causes downstream effects (shock, DIC, edema, fever)
Strep agalactiae
GBS
Pneumonia, meningitis, sepsis (all mainly in babies)
25% of women have as normal vaginal flora. Prophylaxis during labor if +
DDx: Neonatal sepsis/meningitis
GBS, listeria, E. coli
Lancefield groups (Strep)
based on differences in C carbohydrate on bacterial cell walls
Enterococci
gram+ve bacteria (vs. Enterobacter - gram-ve)
Include E faecalis and E. faecium
PCN G resistant, cause UTI and subacute endocarditis
Can grow in 6.5% NaCl
Include VRE - nosocomial infections
Group D (along with non-enterococcal group D strep, e.g. bovis)
Strep bovis
non-enterococcal Group D strep
Highly assoc. with colon cancer
Diphtheria
Corynebacterium diphtheriae
Exotoxin - inhibits protein synthesis via ADP ribosylation of EF-2
Pseudomembranous pharyngitis with lymphadenopathy
Gram+ve rods with metachromatic granules
Diphtheria ABCDEFG
ADP ribosylation
Beta-prophage (encodes toxin)
Corynebacterium
Diptheriae
Elongation Factor 2
Granules
Tx: Diphtheria
antitoxin, PCN + vaccination
Spore formation
Only certain gram+ve rods
When nutrients are limited (at end of stationary phase)
Highly resistant to destruction by heat/chemicals
Have dipicolinic acid in core
No metabolic activity
Must autoclave to kill
Prevalent in people who work with soil
Spore former e.g.s (and sources)
Bunch of Cs and Bs
Soil:
Clostridium perfringens
Clostridium tetani
Bacillus anthracis

B. cereus (reheated rice)
C. botulinum (honey, canned food)
Coxiella burnetii
Obligate aerobe
Nocardia, Pseudomonas aeruginosa, Mycobacterium tb, Bacillus
Pseudomonas aeruginosa seen in which infections?
burn wounds, nosocomial pneumonia, pneumonias in CF pts., hot tub folliculitis
Obligate anaerobes
Clostridium, Bacteroides, Actinomyces
Lack catalase and/or SOD
Foul-smelling (short-chain fatty acids), difficult to culture, produce gas (CO2 adn H2)
Normal flora of GI
What can't you treat Obligate anaerobes with?
Can't treat with aminO2glycosides because they need O2 to get into bacteria
Quellung reaction
Positive in encapsulated bacteria - capsule swells when anti-capsular antisera added
Bacterial capsules
Capsule is antiphagocytic virulence factor
Serves as Ag in vaccines - Pneumovax, HiB, meningococcal vaccines.
Conjugation with protein increases immuno response and T-cell dependent response
Encapsulated bacteria
Strep pneumonia
Klebsiella pneumonia
H. influenzae (esp. B serotype)
Neisseria meningitidis
Susceptibility in asplenic pts and in C3 deficiency
Urease-positive bacteria
UTI-causers:
Proteus mirabilis
Klebsiella pneumoniae
Ureaplasma

H. Pylori
Lysogeny
Genes for these 5 bacterial toxins encoded in a lysogenic phage
ABCDE
shigA-like toxin
Botulinum toxin (certain strains)
Cholera
Diphtheria
Erythrogenic toxin of S. pyogenes
Tetanus
Clostridium tetani (tennis-racket shaped)
Blocks GABA release and also gly rlelease from Renshaw cells in SC. can infect neonates via colonization of umbilical stump, though vaccination of mother is protective via IgG
Botulinum toxin acts where, does what?
inhibits Ach release - flaccid paralysis
C. perfringens toxin
lecithinase - can cause myonecrosis (gas gangrene) and hemolysis
C. difficile toxin
Enterotoxin - causes diarrhea by acting as chemoattractant for neutrophils, which release cytokines leading to mucosal inflammation and GI fluid loss
cytotoxin - exotoxin that kills enterocytes by depolymerizing actin filaments, causing cell death, followed by pseudomembranous colitis
Dx - C-dif toxin in stool
Tx: C. dif
Metronidazole or
Vancomycin
Anthrax
obligate aerobe
B. anthracis only bacterium with protein capsule (contains D-glutamate)
Malignant pustule (painless ulcer)
can progress to bacteremia and death
Contact anthrax infection
Black skin lesions - vesicular papules covered by black eschar
Wool sorter's disease - inhalation of spores from contaminated wool
Inhaled anthrax infection
flu-like symptoms that rapidly progress to fever, pulmonary hemorrhage, mediastinitis, shock.
Acquired by ingestion of unpasteurized milk/cheese and deli meats or by vaginal transmission during birth
Listeria monocytogenes
Form 'actin rockets' by which they move from cell to cell
Listeria monocytogenes
Only gram+ve with endotoxin
Listeria monocytogenes
Tumbling motility
Listeria monocytogenes
Dz: Listeria monocytogenes
Can cause amnionitis, septicemia, spontaneous abortion in pregnancy
Granulomatosis infantiseptica, neonatal meningitis, meningitis in IC pts., mild gastroenteritis in healthy pts.
Actinomyces vs. Nocardia
Shared characteristics
Both gram+ve rods forming long branching filaments resembling fungi
Actinomyces vs. Nocardia
A. israelii - oral/facial abscesses that may drain through sinus tracts (with yellow 'sulfur granules') in skin
Nocardia asteroides - weakly acid-fast aerobe in soil, causes pulmonary infection in IC pts.
Tx: Actinomyces vs. Nocardia
SNAP:

Sulfa for
Nocardia
Actinomyces use
Penicillin
Primary Tb
Nonimmune host (usually child) gets it --> Ghon focus (Tb granulomas - usually lower lobes). + hilar nodes = Ghon complex
Primary Tb possible effects
heals by fibrosis --> immunity and HPY --> Tb+
progressive lung dz. (HIV/malnutrition) --> death (rare)
Severe bacteremia --> miliary Tb --> death
Preallergic lymphatic or hema- dissemination --> dormant Tb bacilli in several organs --> reactivation in adult life
Secondary Tb
Reinfection (partially immune hypersensitized host, usually host) or reactivation
Fibrocaseous cavitary lesion, usually upper lobes
Extrapulmonary Tb infects what, causing what?
CNS (parenchymal tuberculoma or meningitis)
Vertebral body (Pott's dz)
Lymphadenitis
Renal
GI
Meaning of PPD+
current infection, past exposure, BCG vaccinated
Meaning of PPD-
no infection or
Anergic (steroids, malnutrition, IC, sarcoidosis, elderly)
Mycobacterium infection
all acid-fast
IL-12 receptor deficiency predisposes
Don't pick up gram stain
Lowenstein-Jensen culture for Tb, but takes two weeks, so do acid stain and don't wait for culture to start prophylaxis
Sx: M. kansasii
pulmonary Tb-like Sx
M. avium-intracellulare
often resistant to multiple drugs, causes disseminated disease in AIDS
AIDS-defining
MAI Prophylaxis
CD4 < 100 : azithromycin
CD4 < 75 : clarithromycin
M. marinium
mycobacterium
skin infections associated with aquatic activities, even from changing aquarium with a cut. Can even cause septic arthritis and osteomyelitis
M. leprae
What kind? Gram stain? What dz? Mechanism of disease?
Mycobacterium
Doesn't gram stain
Leprosy (Hansen's disease)
Infects skin and superficial nerves --> nerve death --> unnoticed injuries --> appendage loss
Armadillo reservoir
Hansen's disease
also in foot pads of mice
Mycobacterium leprae characteristics
acid-fast bacillus that likes cool temperatures (infects skin, superficial nerves [Schwann Cells]), cannot be grown in vitro
Loss of eyebrows, nasal collapse, Lumpy earlobe, leonine facies, cutaneous hypopigmentation in plaques (often accompanied by hair loss)
lepromatous leprosy
Nasal collapse/deformity
Leprosy
Syphilis (saddle nose deformity)
FAS (short, upturned nose with loss of bridge)
Yaws (treponema pertenue) - destruction of nasal bone and cartilage after five years
Lepromatous leprosy
worse of two types. Failed cell-mediated immunity. Lethal.
Loss of eyebrows, nasal collapse, Lumpy earlobe, leonine facies
Tuberculoid leprosy
self-limited
Tx (primary): Leprosy
Long-term dapsone
6 mos - 2 years
Toxicity - hemolysis, methemoglobinemia
Tx (alternative): Leprosy
Rifampin
Clofazimine/Dapsone combination
Gram-ve (pink)
cocci
glu-
Moraxella catarrhalis (ear infections)
gram-ve (pink)
cocci
glu+
maltose fermenter
N. meningitidis
gram-ve (pink)
cocci
glu+
maltose non-fermenter
N. gonorrhoeae
gram-ve (pink)
coccoid rods
Haemophilus influenzae
Pasteurella (animal bites)
Brucella
Bordetella pertussis
gram-ve (pink)
Rods
Lac+ (pink on MacConkey)
Fast fermenting
Klebsiella
E. coli
Enterobacter
gram-ve (pink)
Rods
Lac+ (pink on MacConkey)
Slow fermenting
Citrobacter
Serratia
Others
gram-ve (pink)
Rods
Lac- (White on MacConkey)
Oxidase-
Shigella
Salmonella
Proteus
gram-ve (pink)
Rods
Lac- (White on MacConkey)
Oxidase+
Pseudomonas

likes air, obligate aerobe
Gram-ve bacteria and PCN
gram-ves resistant to PCN G and Vanco (outer membrane layer inhibits entry), but may be susceptible to PCN derivates (e.g. ampicillin)
Neisseria infections
absence of MAC (C6,7,8) = prone to these infections
Both glu+, IgA protease producers, gram-ve diplococci
N. gonorrhoeae
No polysaccharide capsule
Maltose-
No vaccine or lasting immunity because of frequent Ag variation
STI
Causes gonorrhea (all these also caused by chlamydia): septic arthritis, neonatal conjunctivitis, PID (ascending infection. urethritis --> cervicitis --> endometritis --> sapingitis --> liver capsule (Fitz-hugh Curtis Syndrome). Epididymitis in males
N. meningococci
Polysaccharide capsule
Maltose-
Vaccine
Respiratory and oral secretions
Causes meningococcemia and meningitis, Waterhouse-Friderichsen syndrome (adrenal hemorrhage, shock, sepsis, adrenocortical insufficiency)
Haemophilus influenzae
Epiglottitis, meningitis, otitis media, pneumonia
Small gram-ve (coccobacillary) rod
Aerosol transmission
Most invasive dz. caused by B capsule
IgA protease
Epiglottitis - 2-7 y/o, pharyngitis, drooling, sniffing dog position (to extend airway), omega sign (swollen epiglottis) on laryngoscopy
Haemophilus influenzae
Tx: Haemophilus influenzae meningitis
ceftriaxone
(same for GC meningitis)
Haemophilus influenzae prophylaxis
Rifampin - for close contacts
HiB vaccine
capsular polyribosyl-ribitol-phosphate (PRP) polysaccharide conjugated to Diphtheria toxoid or other protein to improve immune system recognition and promote class-switching
Given between 2-18 months
Legionella pneumophila - dz.
Legionnaire's disease - severe pneumonia. Pontiac disease - mild influenza

Dx: Urinary Ag test
Atypical pneumonia. Sx not as bad as CXR implies
Aerosol transmission from environmental water source habitat, no person-to-person transmission
Legionella pneumophila
Atypical pneumonia
Sx not as bad as CXR implies
Treat all with macrolides - azithro/erythromycin
Charcoal yeast extract with iron and cysteine
Legionella pneumophila culture
Infects CF pts, IC pts, ventilator (ICU) pts
Pseudomonas aeruginosa
Pseudomonas aeruginosa dz.
burn victims, UTIs, sepsis (black lesions) with high mortality, endocarditis (IVDA), corneal infections (contact lens wearers), diabetic osteomyelitis, hot tub folliculitis. water source. endotoxin (fever, shock), exotoxin A (inactivates EF-2)
Pseudomonas aeruginosa characteristics
obligate aerobe, blue-green pigment (pyocyanin), gram-ve rod, lac-, oxidase+, grapelike odor
Tx: Pseudomonas aeruginosa
aminO2glycoside plus extended spectrum penicillin (e.g. piperacillin, ticarcillin) to avoid high mortality sepsis
Enterobacteraciae family
E. coli, Salmonella, Shigella, Klebsiella, Enterobacter, Serratia, Proteus

All have somatic O Ag (polysaccharide of endotoxin), capsular (K) Ag related to virulence, flagellar (H) Ag in motile species.

All glu+ and Oxidase-
Tx: Enterobacteriaciae
meropenem or
imepenem with cilastatin
Tx: Enterobacteriaciae
meropenem or
imepenem with cilastatin
Klebsiella
Aspiration pneumonia in diabetics, alcoholics, Red currant jelly sputum, mucoid sputum, nosocomial UTIs

Upper lung cavitations
Salmonella and Shigella:
Characteristics
Pathology
Both lac-, invade intestinal mucosa and can cause bloody diarrhea. Both never normal flora, always pathogenic.
Salmonella vs. Shigella
Salmonella have flagella, disseminate hematogenously, produce H2S, Sx may be prolonged by AB Tx. Typically monocytic response.

Shigella more virulent (10 vs. 100,000 organisms). Immotile, but can propel selves within cell with actin polymerization
Shigella
bacterial dysentery - watery diarrhea for 1-2 days, then gets painful, bloody and mucusy with wall invasion. Invade by entering M cells of Peyer's patches, escape phagosome, spread laterally to other epithelial cells, release shiga-toxin, a subunit of which inhibits 60S, blocking protein production and leading to cell death.
Shigella flexneri
Reiter's syndrome - can't see, can't pee, can't climb a tree
Salmonella enteritidis
MCC of food associated diarrhea in developed countries - poultry, eggs, AB Tx can prolong carrier state
Salmonella Typhi
typhoid fever - fever, diarrhea, headache, rose spots on abdomen, can remain in gallbladder chronicaly. Mimics appendicitis because of abdominal pain and fever
Yersinia enterocolitica
Usually transmitted from pet feces (e.g. puppies), contaminated milk or pork. Outbreaks in day-care centers. Mimics Crohn's or appendicitis
H. pylori characteristics
gram-ve rod, urease+ (thus urease breath test)
Tx: H. pylori
Triple therapy
1. bismuth, metronidazole and either tetracyclin or amoxicillin
2. (more costly) metronidazole, omeprazole, clarithromycin
Animal associated bacteria:
Cat Scratch Dz. -
cat/dog bites -
cat feces -
Animal urine -
Rat bites -
Cat Scratch Dz. - Bartonella henselae
cat/dog bites - Pasteurella multocida
cat feces - Toxoplasma
Animal urine - Leptospira
Rat bites - Spirillum minus
Spirochetes characteristics, examples, visualization
spiral shaped with axial filaments
Borellia (big) - light microscopy
Leptospira
Treponema - dark field
E. coli is the MCC of what?
diarrhea, UTI, neonatal meningitis/sepsis/pneumonia
ETEC
enteroToxogenic E. coli - Traveler's diarrhea.
Similar to cholera - rice-water diarrhea, no invasion, no bloody diarrhea, no fever
Tx: TMP-SMX or fluoroquinolones
Tx: ETEC
TMP-SMX or fluoroquinolones
EHEC
enteroHemorrhagic E. coli - hamburgers. O157:H7
HUS - hemolytic anemia, uremia, thrombocytopenia
MCC septic arthritis in young sexually active pts
Opthalmia in neonates (vertical transmission via delivery) - sticky eye discharge - can cause blindness
N. gonorrhoeae
EPEC
enteroPathogenic E. coli - similar to shigella - bloody diarrhea
EIEC
enteroInvasive E. coli - intestinal wall invasion, fever, bloody diarrhea
Bacteroides fragilis
most abundant organism in LI. Peritoneal abscess in trauma, surgery, appendix perforation
UTI causers/Tx
E. coli
Klebsiella pneumoniae
Proteus mirabilis
Staph saprophyticus
S. aureus/Pseudomonas if nosocomial

Tx - TMP-SMX, 1st gen Ceph, aminopenicillins (these two good in pregnancy, NOT TMP-SMX because of DNA synthesis), nitrofurantoin
Tx: UTI
TMP-SMX, 1st gen Ceph, aminopenicillins (these two good in pregnancy, NOT TMP-SMX because of DNA synthesis), nitrofurantoin
Proteus mirabilis
enterobacter
very motile, can't grow in agar, UTI, urease+, staghorn renal calculi
Leptospira interrogans
interrogans = question mark shape
Water contaminated with animal urine
Flu-like Sx, fever, headache, abdominal pain, JAUNDICE, prevalent in tropics
Weil's dz.
icterohemorrhagic leptospirosis - severe form with jaundice and azotemia from liver and kidney dysfunction. fever, hemorrhage, anemia
Lyme dz. - Reservoirs, carriers
transmitted by Ixodes tick, mice reservoirs, deer required for tick life cycle
Lyme dz. classic Sx
erythema chronicum migrans, also affects joints, CNS, heart
Also: Bell's palsy (bilateral), Arthritis, cardiac block
Lyme dz stages
1 - erythema chronicum migrans, flu-like Sx
2 - neurologic and cardiac manifestations
3 - chronic monoarthritis, migratory polyarthritis
Tx: Lyme
doxycycline
Tx: Lyme
doxycycline
Treponemes
Disease, manifestations, transmission, epidemiology, serology of less common one
T. pallidum - syphilis
T. pertenue - yaws - infection of skin, bone, joints --> healing with keloids --> severe limb deformities. Dz. of tropics. Not STD (but VDRL positive)
Destruction of nasal bone + cartilage if untreated for 5+ years
Primary syphilis
painless chancre (with many treponemes inside) - localized dz.
Secondary syphilis
Systemic dz. with constitutional Sx, maculopapular rash (palms and soles), condyloma lata. Treponemes present in condyloma. Alopecia ariata (bald patches on scalp)
Tertiary Syphilis
Gummas (chronic granulomas), aortitis (vasa vasorum destruction), neurosyphilis (tabes dorsalis - dorsal columns lost --> sensory deficit (proprioception) --> locomotor ataxia), Argyll Robertson pupil
Sx: broad-based ataxia, positive Romberg, Charcot joints, stroke without HTN
Tertiary Syphilis
Argyll Robertson Pupil
Accommodates but doesn't react - tertiary syphilis
FTA/VDRL
FTA more specific, earliest positive, remains positive longer (even after treatment)
VDRL false positives
Dx syphilis
False positives - SLE, viral infection (mono, hepatitis), some drugs, rheumatic fever, leprosy

VDRL: Viruses, Drugs, Rheumatic fever, Lupus/Leprosy
Bacteria - dairy products, contact with animals
Brucella spp. - brucellosis - undulant fever (Unpasteurized dairy gives Undulating fever)
Tick bite, RABBITS, deer
Francisella tularensis
Flea bite, rodents, especially prairie dogs
Yersinia pestis - plague
Gardnerella vaginalis
pleomorphic, gram-variable rod
Vaginosis - off-white/gray vaginal discharge, fishy smell on KOH prep, nonpainful (Mobiluncus, an anaerobe, also involved)
Sexual activity not necessary for transmission
Clue cells
Tx: Gardnerella vaginalis
metronidazole (GET GAP on the metro)
Rickettsiae general characteristics, classic symptoms
obligate intracellular that need CoA and NAD. All but Coxiella transmitted by arthropod vector and cause Headache, Fever, Rash (classic triad)
Why is Q fever strange?
no rash, no vector, negative Weil-Felix (for Rickettsiae), spore former that can survive for long time outside host, doesn't have Rickettsia as genus name (Coxiella burnetii), causes pneumonia

Inhaled aerosol, interstitial pneumonia seen in farmers
Tx: Rickettsial organisms
Tetracycline
Rash: Rickettsia vs. Typhus
Rickettsia starts on wRists then to trunk
Typhus on Trunk, then spreads out
Rocky Mountain Spotted Fever
Rickettsia rickettsii
Classic triad: Headache, fever, rash on palms/soles --> wrists, ankles --> trunk
Endemic to EAST coast
DDx: Rash on palms and soles
Coxsackie A
Rocky mountain spotted fever
Syphilis (secondary)

You use your palms and soles when you drive CARS
Desquamation of palms/soles
Kawasaki Dz., Hg poisoning, Rocky Mt. Spotted Fever
Weil-Felix reaction
antirickettsial Ab, which cross-react with Proteus Ag. Positive for typhus, Rocky Mt. Spotted Fever, negative for Q fever
Chlamydiae forms
Elementary bodies Enter via Endocytosis
Reticulate body Replicates in cell by fission, reorganize into (smaller) elementary bodies
Chlamydiae characteristics
cell wall lacks muranic acid, can't make ATP (obligate intracellular), causes mucosal infections
Chlamydia trachomatis
reactive arthritis, conjunctivitis, nongonococcal urethritis, PID
C. psittaci/pneumoniae
cause atypical pneumonia, transmitted via aerosol

Psittaci has avian reservoir
Dx: Chlamidiae
cytoplasmic inclusions seen on Giemsa or fluorescent Ab-stained smear
Tx: Chlamidiae
erythromycin or tetracycline
Chlamydia trachomatis serotypes
ABC
D-K
L1/2/3
ABC - chronic eye infection (trachoma), cause blindness in Africa
D-K - Urethritis/PID, ectopic pregnancy, neonatal pneumonia, neonatal conjunctivitis
L1/2/3 - lymphogranuloma venereum (acute lymphadenitis). Primary ulcers, then 6-8 weeks later, get lymphadenopathy, later get bad rectal dz that can be mistaken for UC

ABC - Africa/Blindness/Chronic infection
L - lymphogranuloma venereum
D-K - everything else
Mycoplasma pneumoniae
classic cause of 'walking' pneumonia (insidious onset, headache, nonproductive cough, diffuse interstitial infiltrate
High titer of cold agglutinins (IgM)
Grown on Eaton's agar
No cell wall, not gram stained
Only bacterial membrane with cholesterol
More common in pts <30
Outbreaks in military recruits, prisons
Block cell wall synthesis by inhibition of peptidoglycan cross-linking
Penicillin, ampicillin, ticarcillin, piperacillin, imipenem, aztreonam, cephalosporins
Dz: HSV-1
gingivostomatitis, keratoconjunctivitis, temporal lobe encephalitis (MCC sporadic encephalitis in US), herpes labialis
Transmission: HSV-1
respiratory secretions, saliva
HSV-1 hides in?
Trigeminal ganglion
Dz: HSV-2
Outbreak occurrence/frequency?
multiple ulcers in genital region. Most outbreaks in first year, usually decreased outbreaks over time. Also neonatal herpes
Transmission: HSV-2
Sexual contact, perinatal
HSV-2 hides in?
S2-S3 ganglia
Dz: VZV
aka HHV 3
Shingles, Chicken pox (different aged lesions at same time), encephalitis + pneumonia (especially when adults get for first time)
Transmission: VZV
respiratory secretions
VZV remains dormant in?
DRG and trigeminal
Dz: EBV
aka HHV 4
Infectious mononucleosis, Burkitt's lymphoma, Hodgkin's lymphoma, nasopharyngeal carcinoma, CNS lymphoma in IC pts
Virus causing fever, fatigue, hepatosplenomegaly, pharyngitis, lymphadenopathy (especially posterior cervical nodes)
EBV - peak incidence 15-20 years.
Virus causing abnormal CD8 cells with foamy/downy appearance in circulation, hairy oral leukoplakia
EBV
Very high fevers (102-104) in infant with no other signs, when fever breaks, rash breaks out, lasting a few hours
HHV 6 - Roseola infantum. Rash over whole body
HHV 7 associated with?
Monkey bites
Dx: EBV
Positive monospot test - heterophil antibodies detected by agglutination of sheep RBCs
E.g.s of heterophile- mononucleosis
CMV, Listeria, toxoplasma
Dx: HSV-1/2, VZV
Tzanck test - smear of opened skin vesicle to detect multinucleated giant cells. Also intranuclear Cowdry A inclusions
Dz: CMV
congenital infection (TORCH), mononucleosis (negative monospot), pneumonia.
Dx: virus causing Owl's eye appearance
CMV due to intranuclear Cowdry A inclusions
Transmission: CMV
Congenital, transfusion, sexual contact, saliva, urine, transplant
Dz: HAV
Incubation period?
Who's susceptible?
Carrier state?
acute: short incubation (3 weeks), jaundice, liver dz.
Alcoholics, IVDA, HepB/C pts all susceptible and should be vaccinated.
No carriers
Usually asymptomatic
Transmission: HAV
fecal-oral route
Infective agent: HAV
RNA Picornavirus - pico = small
Dz: HBV
long incubation (3 months).
Carrier state
Vaccine
Chronic, cirrhosis
Hepatocellular carcinoma association. Incorporates its DNA into hepatocytes. Have to monitor alpha-fetoprotein levels.
Transmission: HBV
parenteral, sexual, maternal-fetal
Infective agent: HBV
DNA hepadnavirus - hepa + dna + virus
cellular RNA polymerase transcribes RNA from DNA template. Reverse transcriptase transcribes DNA from RNA intermediate. However, virion enzyme is a DNA-dependent DNA polymerase
Dz: HCV
Mostly same clinical presentation as HBV, but no vaccine
Chronic, cirrhosis, carcinoma, carriers
Hepatocellular carcinoma association. Have to monitor alpha-fetoprotein levels.
Transmission: HCV
primarily blood (not sexual). Common cause of post-transfusion hepatitis and hepatitis of IVDA in US
Infective agent: HCV
RNA flavivirus
Dz: HDV
Defective virus Dependent on HBVsAg as envelope. Can coinfect or superinfect (worse Px)
Infective agent: HDV
RNA deltavirus
Dz: HEV
Resembles HAV in course, severity, incubation. High mortality rate in pregnant women
Transmission: HEV
transmitted enterically and causes water-borne epidemics
Infective agent: HEV
RNA hepevirus = hepatitis + E + virus
Significance of serological marker:
IgG HAVAb
Indicates prior infection; protective against reinfection
Significance of serological marker:
IgM HAVAb
IgM Ab to HAV - best test to detect ACTIVE HepA
Significance of serological marker:
HBsAg
Active disease
Significance of serological marker:
HBsAb
recovery from exposure, including vaccination. Provides immunity
HBcAg
New disease
HBcAb
significance of positive titer
Hx of dz - have recovered or still have it. Not seen in vaccinated patients. Positive during window period. IgM = recent disease. IgG = chronic disease
Significance of serological marker:
HBeAg
Pt. is contagious
Indicator of active viral replication
Significance of serological marker:
HBeAb
Pt. not very contagious
Serological test results in HBV
Acute disease
HBsAg:
HBsAb:
HBcAb:
Serological test results in HBV
Acute disease
HBsAg: +
HBsAb: -
HBcAb: -
HBsAb: IgM in acute stage, IgG in chronic or recovered stage
Serological test results in HBV
Window Phase
HBsAg:
HBsAb:
HBcAb:
Serological test results in HBV
Window Phase
HBsAg: -
HBsAb: -
HBcAb: +
Pt. has HBsAb, but it is bound to HBsAg and not detected
Serological test results in HBV
Complete recovery
HBsAg:
HBsAb:
HBcAb:
Serological test results in HBV
Complete recovery
HBsAg: -
HBsAb: +
HBcAb: +
Serological test results in HBV
Chronic Carrier
HBsAg:
HBsAb:
HBcAb:
Serological test results in HBV
Chronic Carrier
HBsAg: +
HBsAb: -
HBcAb: +
Serological test results in HBV
Immunized
HBsAg:
HBsAb:
HBcAb:
Serological test results in HBV
Immunized
HBsAg: -
HBsAb: +
HBcAb: -
DNA virus characteristics and exceptions
HHAPPPP (Hepadna, Adeno, Pox, Parvo, Papilloma, Polyoma
DS (except parvo - SS)
Linear (except papilloma/Polyoma (circular, supercoiled) and hepadna (circular, incomplete))
Icosahedral (except pox - complex)
Replicate in nucleus (except popx - carries own DNA-dependent RNA polymerase)
Adenovirus
DNA, constellation - combination of some of following:
Febrile pharyngitis - sore throat
Pneumonia
Conjunctivitis (pink eye)
Gastroenteritis
Parvovirus
ONLY SS DNA virus
B19 virus - aplastic crises in SCD pts. Prodromal febrile URI in child, followed by sudden onset 7-10 days later of 'slapped cheek' rash (ERYTHema infectiosum - 5th Dz [think slapped cheek - CN V]) - targets ERYTHROID precursors, replicates in BM, hydrops fetalis - O (other) in TORCH
Papillomavirus
DNA/RNA?
Causes what diseases? What strains cause cancer?
DNA
HPV - warts (different strains cause warts + cancer), CIN (which can lead to cervical cancer), VIN (which can lead to vulvar cancer), cancer of penis.
Cancer associated - HPV 16, 18
Polyomavirus
DNA
JC virus - progressive multifocal leukoencephalopathy (PML) in HIV
Poxvirus
DNA
Smallpox - germ warfare
Vaccinia - cowpox - infected cow udders
Molluscum contagiosum - raised lesions with central pit. Very common vaginally. Can be transmitted vertically to infant. No clinical problems, can freeze off, but resolves spontaneously in few years.
Reoviruses
ONLY DS RNA viruses
Reovirus - Colorado Tick Virus
Rotavirus
Dz: Rotavirus
Infects whom/when/what settings/course/mechanism?
Histological presentation?
MCC fatal diarrhea in children
acute diarrhea in children in winter months, especially in day care centers, KG
Villous destruction with atrophy leads to decreased absorption of Na and water
1-2 week, green foul-smelling diarrhea
Picornaviruses
RNA
PERCH on a 'peak' (pico)
Polio
Echo
Rhino
Coxsackie
HAV
Poliovirus
Picornavirus RNA
Salk/Sabin vaccines
Affects anterior horns
Dz: Echovirus
RNA picornavirus
MCC aseptic meningitis, which is not bad, presents like cold/flu (except MC in summer months), no hospitalization necessary.
Also - myocarditis
Rhinovirus
RNA Picornavirus
MCC common cold
Coxsackievirus
RNA Picornavirus
#2 MCC aseptic meningitis (after echo)
Herpangina - febrile pharyngitis
hand, foot, mouth dz.
myocarditis
Calicivirus
RNA
Norwalk virus - viral gastroenteritis
Cruise ships
Viruses that cause aseptic meningitis and myocarditis
Echovirus
Coxsackievirus
both RNA picornaviruses
Flaviviruses
RNA
Flavi=yellow
HCV, Yellow fever, Dengue fever, St. Louis Encephalitis, West Nile Virus
Yellow Fever Virus
RNA flavivirus (arbovirus)
Monkey/human reservoir, mosquito (Aedes) vector
Sx: high fever, black vomitus, jaundice
Councilman bodies (acidophilic inclusions seen in toxic or viral hepatitis) may be seen in liver
Dengue
RNA Flavivirus
Life-threatening
break-bone fever, hemorrhagic shock syndrome
St. Louis Encephalitis
RNA Flavivirus
West Nile virus
Reservoir, vector, host?
RNA Flavivirus
Reservoir = birds
Vector = mosquitoes
Incidental hosts = humans, dogs, horses
Sx: West Nile virus
RNA Flavivirus
flu-like
1/150 get meningitis or even encephalitis
Flaccid paralysis can develop - anterior horns
Altered consciousness, possibly death
Dx: West Nile Virus
IgM anti-WNV
IgG would indicate previous infection
Tx: West Nile Virus
supportive care
HTLV
What kind of virus?
What does it cause?
RNA Retrovirus
T-cell leukemia
Coronavirus
What kind of virus?
What two things does it cause?
RNA virus
2nd MCC common cold
SARS, which can lead to ARDS
Orthomyxovirus
RNA
Influenza
Influenza shift vs. drift
Oh Shift!
Shift - pandemic - reassortment of viral genome, usually from mixing with animal virus
Drift - minor (Ag drift) changes based on random mutation. Vaccines try to predict this.
Orthomyxovirus characteristics
RNA
Hemagglutinin (promotes viral entry) and Neuraminidase (promotes progeny virion release)
Patients at risk for fatal bacterial superinfection
Paramyxoviruses
RNA
Infect children
Parainfluenza - croup
RSV - bronchiolitis in babies
Rubeola (Measles)
Mumps
Parainfluenza
RNA Paramyxovirus
Croup - laryngotrachobronchitis
Barking seal cough
Respiratory distress, inspiratory stridor
Leading cause of hospitalization in <4y/o pts.
Dx: Parainfluenza
Steeple sign - trachea narrows near top
Tx: Parainfluenza
cool moist humidifier at night (when Sx worst)
racemic epinephrine
1 dose dexamethasone
Mostly supportive
Sx: RSV
bronchiolitis - can cause pneumonia esp. in infants. brassy cough. wheezing, respiratory distress.
Suspect if asthma-like Sx in pt <2 y/o with acute onset in winter months.
Prophylaxis: RSV - what and to whom/when?
Passive immunization with palavizumab - monoclonal RSV Ig - monthly in winter months in premies (&lt;34 weeks gestation) or chronic lung dz infants
Tx: RSV
albuterol or racemic epinephrine
DON'T use steroids - not beneficial and potential for harm
Rhabdovirus
RNA
Rabies
Rabies
Negri bodies - cytoplasmic inclusions in infected neurons
Bullet shaped capsid
Long-incubation period (weeks to months) - can vaccinate after bite
Fatal encephalitis with seizures, hydrophobia, hypersalivation, pharyngeal spasm
Travels to CNS via retrograde fashion up nerve axons
Togaviruses
RNA
Rubella (German measles)
Eastern equine encephalitis
Western equine encephalitis
Rubella (German Measles)
What kind of virus/family?
Dz characteristics in adult/child/neonate
RNA Togavirus
German (3-day) measles
Fever, lymphadenopathy, arthralgias, fine truncal rash
Mild disease in children
Serious congenital disease (PDA association) - TORCH dz
Winter viruses
Flu, RSV, rota
Rubeola
RNA paramyxovirus
Measles
Koplik spots (red spots with blue-white center on buccal mucosa) diagnostic
SSPE (subacute sclerosing pan-encephalitis) years later
encephalitis and giant cell pneumonia rare
Rash spreads from head to toe - bucket of paint poured on head
3 Cs - Cough, Conjunctivitis, Coryza (runny nose)
Mumps
RNA Paramyxovirus
Parotitis (increased amylase), orchitis (rare), aseptic meningitis
Filoviruses
Type?
Name two diseases
RNA
Ebola (--> DIC), Marburg hemorrhagic fever
Often fatal
Arenaviruses
RNA
LCMV - lymphocytic choriomeningitis virus
Lassa fever encephalitis - mice
Bunyaviruses
RNA
California encephalitis
Sandfly/Rift Vally fevers
Crimean-Congo hemorrhagic fever
Hantavirus - hemorrhagic fever, pneumonia, associated with mice
Avian flu
RNA, Orthomyxovirus, H5N1
only spread birds --> human for now (human --> human shift would cause pandemic)
Pancytopenia, URI, GI (diarrhea/fever), increased LFTs
Dx: Avian flu
reverse transcriptase PCR or viral culture
Tx: Avian flu
oseltamivir
HIV proteins
Envelope:
Capsid:
HIV proteins
Envelope: gp41, gp120
Capsid: p24
HIV binding
CXCR4 and CD4 on T cells, CCR5 and CD4 on Macrophages
HIV immunity
homozygous CCR5 mutation = immunity
Heterozygous CCR5 mutation = slower course
Dx: HIV
What tests to RULE OUT and RULE IN?
Presumptive: ELISA - high false+ and low threshold - RULE OUT test
Confirmed with Western blot assay - RULE IN
HIV monitoring/Dx: what test?
HIV PCR/viral load tests
HIV false tests
falsely negative in first 1-2 months of HIV infection
Falsely positive initially in babies born to infected mothers (anti-gp 120 crosses placenta) - use viral load instead.
HIV-associated infections, CD4 count and prophylaxis &lt; 400
oral thrush, tinea pedis, reactivation VZV, reactivation Tb, other bacterial infections (e.g. H. flu, S. pneumoniae, Salmonella)
HIV-associated infections, CD4 count and prophylaxis &lt;200
Reactivation HSV, crypto, Isospora, disseminated coccidio, PJP - TMP-SMX (or dapsone if sulfa allergy)
HIV-associated infections, CD4 count and prophylaxis < 100
Candidal esophagitis, toxo, histo
Azithro for MAI
HIV-associated prophylaxis CD4 < 75
Clarithro
Neoplasms associated with HIV
Kaposi's Sarcoma(HHV-8), HPV CIN, primary CNS lymphoma, non-Hodgkin's lymphoma
HIV encephalitis
late in HIV course. Gains CNS access via infected macrophages. See microglial nodules with multinucleated giant cells.
Prions
Infectious proteins
Creutzfeldt-Jakob Disease - rapid progressive dementia - kuru, scrapie (sheep), mad cow disease. Spongiform encephalopathy association
HIV vertical transmission risk in pregnancy
risk of vertical transmission is in blood-mixing due to trauma or during labor, so C-section often preferred. ZDV proph in pregnancy
Normal flora: Dominant
Skin -
Nose -
Oropharynx -
Dental plaque -
Colon -
Vagina -
Skin - S. epidermidis
Nose - S. epidermidis, colonized by S. aureus (give AB in nose as well if MRSA)
Oropharynx - Viridans
Dental plaque - S. mutans
Colon - Bacteroides > E. coli
Vagina - Lactobacillus, colonized by E. coli and GBS
Bugs causing food poisoning
Seafood -
Meats, mayonnaise, custard -
Reheated meat dishes -
Improperly canned foods -
Undercooked meat -
Poultry, meat, eggs, reptiles -
Reheated rice -
Seafood - Vibrio
Meats, mayonnaise, custard - S. aureus (preformed toxin)
Reheated meat dishes -C. perfringens
Improperly canned foods - C. botulinum (bulging cans)
Undercooked meat - E. coli O157:H7
Poultry, meat, eggs, reptiles - Salmonella
Reheated rice - B. cereus
Bugs causing bloody diarrhea
Campylobacter - comma/s-shaped
Salmonella - Lac-
Shigella - Lac-, very low ID50, Shiga toxin
EHEC - O157:H7 - HUS, shiga-like toxin
EIEC - invades colonic mucosa
Yersinia - day care outbreaks, pseudoappendicitis
C. dif - either bloody or watery
E. histolytica - protozan - amebic dysentery
Bugs causing watery diarrhea
ETEC - ST and LT toxins
Vibrio cholerae - Comma-shaped
C. perfringens - also causes gas gangrene
Protozoa - Giardia, Crypto (in IC pts)
Viruses - Rota (winter), adenovirus (pink eye + diarrhea), Norwalk (cruise ships)
Pneumonia in neonates (< 4 weeks)
GBS
E. Coli
(Remember, Listeria causes meningitis in this group)
Broad spectrum - Ampicillin + Gentamycin
Pneumonia in Children (4 weeks - 18 years)
Viruses (RSV) (MCC)
Mycoplasma
Chlamydia pneumoniae
Streptococcus pneumoniae
Broad spectrum: Cephalosporin for S. pneumo, Macrolide for atypical pneumonias
Pneumonia in Adults (18-40)
Top 3 causes and Tx
Mycoplasma
C. pneumoniae
S. pneumoniae
Broad-spectrum - Macrolides and Cephalosporin (same infective agents as in children, minus the viruses)
Pneumonia in Adults (40-65)
Tx?
S. pneumonia
H. influenzae
Anaerobes
Viruses
Mycoplasma
Broad-spectrum - Cephalosporin + Macrolide + Clindamycin (for anaerobes)
Pneumonia in Elderly (65+)
S. pneumonia, Viruses, Anaerobes, H. influenzae, Gram-ve rods
Broad-spectrum - Imipenem + Cilastatin or Meropenem
Pneumonia in special groups:
Nosocomial -
IC -
Aspiration -
Alcoholic/IVDA -
CF -
Postviral -
Atypical -
Nosocomial - Staph, enteric gram-ve rods
IC - Staph, enteric gram-ve rods, fungi, viruses, PJP (with HIV)
Aspiration - anaerobes
Alcoholic/IVDA - S. pneumoniae, Klebsiella, Staph, aspiration with anaerobes (alcoholic)
CF - Pseudomonas (quinolones)
Postviral - Staph, H. influenzae
Atypical - Mycoplasma, Legionella, Chlamydia
Meningitis in newborns (0-6 mos)
GBS
E. coli
Listeria

Ampicillin + Gentamycin
Meningitis in children (6 mos - 6 years)
S. pneumoniae
N. meningitidis (assoc. w/ severe rash)
HiB
Enteroviruses (echo-, coxsackie) - MCC. (remember: aseptic meningitis > septic)

Ceftriaxone - go to for meningitis
Meningitis in 6-60 years
N. meningitidis
Enteroviruses
S. pneumoniae
HSV
Meningitis in 60+
S. pneumoniae
Gram-ve rods (decreased hygiene)
Listeria
Viral causes of meningitis
enteroviruses (esp. echo/coxsackie), HSV, HIV, West Nile, VZV
Meningitis in HIV
Crypto, CMV, Toxo (brain abscess), JC virus (PML)
CSF findings in Meningitis
Pressure/Cell Type/Protein/Sugar in Bacterial, Fungal/TB, Viral
H=High
N=Normal
L=Low
Bacterial - H/H PMNs/H/L
Fungal/TB - H Lymphos/H/L
Viral - NH/H Lymphos/NH/N
Osteomyelitis causes
Most people - S. aureus
Sexually active - GC (rare) - septic arthritis more common
DM/Drug addicts - Pseudomonas
SCD - Salmonella
Prosthetic replacement - S. aureus, S. epidermidis
Vertebal - M. Tb (Pott's dz)
Cat/dog bites/scratches - Pasteurella multocida
Osteomyelitis tests
Elevated CRP/ESR classic but non-specific - RULE OUT
Definitive test - bone scan/MRI
UTI causes
Ambulatory -
Hospital -
Ambulatory - E. coli Klebsiella, S. saprophyticus (2nd MCC in young, sexually active ambulatory women), Proteus
Hospital - E. coli, Proteus, Klebsiella, Serratia, Pseudomonas, MRSA
UTI epidemiology, predisposing factors
women: men = 10:1 (shorter urethra with fecal flora)
Predisposing factors - flow obstruction, kidney surgery, catheterization, gynecologic abnormalities, diabetes, pregnancy, labial adhesions in infants/toddlers
Male congenital defects --> UTIs
posterior urethral valves --> difficulty emptying bladder, reflux
UTI Sx in elderly
delirium in addition to usuals
UTI bugs
Serratia - some produce red pigment; often nosocomial, drug resistant
E. coli - leading cause, colonies show metallic sheen on EMB agar
Enterobacter cloacae - often nosocomial/drug resistant
Klebsiella - large mucoid capsule, viscous colonies
Proteus - motility causes swarming on agar, produces urease, struvite stones
Pseudomonas - blue-green pigment, fruity odor, usually nosocomial and drug resistant
Congenital Toxoplasma
classic triad:
Chorioretinitis
Intracranial calcifications
Hydrocephalus

May be asymptomatic at birth
Congenital Rubella
sensorineural deafness, cataracts and/or glaucoma, heart defects (PDA, pulmonary stenosis), microcephaly, MR, blueberry muffin baby due to rash, meningoencephalitis, behavioral changes
Congenital CMV
petechial rash, intracranial calcifications, MR, HSmegaly, microcephaly, jaundice, opthrochorioretinitis, optic atrophy, central vision loss, hemolytic anemia. 90% asymptomatic at birth, 15% of whom develop [usually unilateral] hearing loss
Congenital HIV
HSmegaly, neurologic abnormalities, frequent infections
Congenital HSV II
temporal encephalitis, conjunctivitis, vesicular skin lesions, often asymptomatic at birth, most infections transmitted during birth. If active skin lesions, must do C-section
Congenital syphilis - early manifestations
HSmegaly with elevated LFTs, hemolytic anemia, jaundice, rash --> dequamation of palms/soles, sniffles, blood-tinged nasal secretions, radiologic changes at birth including metaphysial dystrophy + periosteitis
Congenital syphilis - late manifestations
the more standard Sx - saddle nose, saber shins, Hutchinson teeth, CN VIII deafness, frontal bossing, etc.
Vaginal discharge + vaginitis DDX (aside from GC/Chlam)
Low pH
physiologic discharge, candidiasis
Vaginal discharge + vaginitis DDX (aside from GC/Chlam)
High pH
Trichomonas, bacterial vaginosis
Vaginal discharge + vaginitis
Physiologic discharge vs. candidiasis
Physiologic discharge presents at puberty, see WBCs on wet prep
Candidiasis - cottage cheese, wet prep: budding yeast + pseudohyphae
Vaginal discharge + vaginitis
Trichomonas vs. bacterial vaginosis
Trichomonas - cervical irritation, strawberry red, fryable cervix. wet prep: triangular, flagellated protozoa
Bacterial vaginosis - wet prep: Clue cells

Either way: Tx - Metronidazole
DDx: Fever in post-op patient
Wind - atelectasis day 1-2
Water - UTI day 3-5
Wound day 5-7
Walking - DVT
'Wein' - thrombophlebitis
Wonder drugs - usually ABs
Sinusitis - from NG tube
Nosocomial infections:
Newborn nursery -
Urinary catheter
Respiratory therapy equip -
Work in renal dialysis unit
Hyperalimentation -
Water aerosols -
Newborn nursery - CMV, RSV
Urinary catheter - E. coli, Proteus
Respiratory therapy equip - Pseudomonas
Work in renal dialysis unit - HBV
Hyperalimentation - Candida
Water aerosols - Legionella
Granulomatous diseases
Tb (only one that's caseating)
Fungal infections (e.g. histoplasmosis)
Syphilis
Leprosy
Cat Scratch Fever
Sarcoidosis
Crohn's disease
Berylliosis
Mechanism: Chronic granulomatous disease
Lack of NADPH oxidase activity or similar enzymes - defect of neutrophil microbicidal activity. Can't make H2O2, but can still make HOCl radical from H2O2 provided by bacteria, so especially susceptible to catalase+ bacteria (e.g. staph). Susceptible to Aspergillus, Nocardia, Serratia, Pseudomonas
Negative NBT dye test
Encapsulated bacteria
Strep pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Klebsiella pneumoniae. Capsule serves as vaccine Ag. Asplenic individuals need to be vaccinated. C3 deficient pts also susceptible
MOPS vs MOPE
MOPS - Meningitis, Otitis media (in children), Pneumonia, Sinusitis - S. pneumoniae
MOPE - Meningitis, Otitis media, Pneumonia, Epiglottitis - H. influenzae
Rickettsial vectors
Rocky Mt. Spotted Fever
Endemic Typhus
Epidemic Typhus
Ehrlichiosis
Q Fever
Rocky Mt. Spotted Fever - tick
Endemic Typhus - fleas
Epidemic Typhus - human body louse
Ehrlichiosis - tick
Q Fever - none
Dimorphic fungi with culture/tissue forms
Sporothrix (cigar shaped or round budding yeast), Coccidioides (Spherules), Histoplasma (oval yeast in macrophages), Blastomyces (large round yeast with single broad based bud)
All but Coccidioides (hyphae with doubly reflective wall) have branching hyphae in tissue
Post-Group A Strep:
Rheumatic fever vs. glomerulonephritis
Glomerulonephritis takes 1-5 weeks and can follow S. pyogenes skin infection OR pharyngitis. Rheumatic fever (with heart murmur, etc.) takes 4-6 weeks and follows ONLY pharyngitis.
Right sided endocarditis
typically occurs in IVDA and typically caused by S. aureus (pseudomonas 2nd MCC). Can develop multiple septic emboli in lungs - infarcts almost always hemorrhagic because of dual blood supply.
V. cholerae sensitivity
prefers alkaline environments, is acid-sensitive. Achlorhydria, food ingestion and antacid ingestion can increase pH of the stomach and decrease the minimum infective dose of V. cholerae by many orders of magnitude
Cold agglutinin causers
S. pneumoniae, EBV, hematologic malignancy
Post-flu bacterial pneumonia-causing pathogens
Top 3: S. pneumoniae, S. aureus, H. influenzae.
Elderly especially susceptible
Route of infection: N. meningitidis meningitis
Pharynx --> blood --> choroid plexus --> meninges
Route of infection: H. influenzae meningitis
Pharynx --> lymphatics --> meninges
Route of infection: S. pneumoniae meningitis
Middle ear --> contiguous tissues --> meninges
(possible route, though unusual)
Route of infection: S. aureus meningitis or CNS abscess
traumatic wound --> leaking CSF --> meninges. Following penetrating skull trauma or neurosurgery, S. aureus introduced from skin
Route of infection: Tb meningitis
Primary lung focus --> blood --> meninges. Chronic meningitis, monocytes and lymphocytes in CSF, primarily affecting basal meninges
HIV resistance
Pol gene mutations responsible for protease variants that are resistant to standard protease inhibitors and structural changes in reverse transcriptase that make it resistant to standard NRTI and NNRTIs.
Env gene mutations enable HIV to escape from host neutralizing Abs.
Oral Thrush causes
Candida albicans - associated with wearing dentures, DM and immunosuppression. Unexplained oral thrush in otherwise healthy person suggests HIV infection possibility.
Mucormycosis
facial pain, headache, black necrotic eschar in nasal cavity - can proliferate in walls of BVs and cause infarction/necrosis of distal tissue. Rhinocerebral, frontal lobe abscesses. Rapid brain infection --> death can follow in 2-4 hours. mold with irregular, nonseptate hyphae branching at right angles.
Tx: Mucormycosis
debridement and amphotericin B
Cryptococcus
Yeast form only, round/oval encapsulated cells with NARROW based buds. Primary infection - lung. MC infection form - meningoencephalitis. Present in soil/pigeon droppings. Dx: india ink, latex agglutination of CSF, Culture (Sabouraud's), Methenamine (GMS)/mucicarmine stains of tissue.
Tx: Cryptococcus
Amphotericin B and flucytosine (acute meningitis), fluconazole for lifelong proph
HIV associated infections and prophylaxis, CD4 < 50
CMV retinitis/esophagitis, disseminated MAI, crypto meningoencephalitis.
Fluconazole
Cat Scratch Dz
Bartonella henselae - low fever, lymphadenopathy, self-limited course
Bartonella henselae
Cat scratch dz
bacillary angiomatosis - red-purple papular skin lesions - may also be found within viscera - fatal if untreated.
Also can cause culture negative endocarditis
Polysaccharide vaccines
S. pneumoniae - can be given in unconjugated form (elderly pts - 23 of 80+ serotypes) or conjugated (infants - 7 of 80+, stimulates T-cell dependent immune (memory) response

N. meningitidis and H. influenzae vaccines also polysaccharide vaccines.
Live attenuated vaccines
bacterial: BCG, typhoid
viral: measles, mumps, rotavirus, VZV, Sabin polio
Killed vaccines
Bacterial and viral e.g.s
What's required for it to induce immunity?
Bacterial: anthrax, cholera, pertussis, plague
viral: HAV, flu, rabies, Salk polio
Require multiple inoculations to induce immunity
MCC Otitis Media
S. pneumoniae, H. influenzae, Moraxella. Chronic infections of this kind suggest humoral immunodeficiency.
Host response: Giardia
Secretory IgA impairs adherence. Persistent giardiasis is a sign of IgA deficiency
Characteristics: E. coli
motile, lac+ gram-ve rods, encapsulated (virulence factor in meningitis)