Common Pathogens in Specific and Systemic Infection

Gonna rlly only add the stuff Aj said in class bc it's the most important

Common cold caused by

Rhinovirus » corona, adeno RSV

Pharyngitis/tonsilitis caused by

Mainly VIRAL: Rhinovirus, adenovirus, EBV

Can be caused by GAS

Sinusitis caused by

BACTERIAL: strep pneumoniae, h. influenza, m. catarrhalis

Laryngitis and Croup caused by

Parainfluenza (Croup), influenza A/B

Epiglottitis caused by

Hemophilus influenza type B (Hib)

Community-Acquired Pneumonia (CAP) caused by

S. pneumoniae (most common)

What are the typical signs of pneumonia vs atypical pneumonia

Typical: Cough, fever, dyspnea

Atypical: Dry cough, low grade fever

Atypical/walking pneumonia caused by

Mycoplasma pneumoniae, chylamydia pneumoniae, legionella

Signs of TB

Chronic cough >2 wk, dry cough, weight loss and anorexia

Streptococcus pyogenes important virulence factors

M protein → Inhibit C3b opsonization

Capsule → Mimicry → Rheumatic fever and post strep glomerulonephritis

Streptolysin O and S → Forms pores on RBC and WBC

S. pneumoniae virulence factors

Capsule → Inhibit C3b → No MC phagocytosis

Pneumolysin → Forms pore

IgA protease → Cleave IgA → no immune clearance

Stages of lobular pneumonia

Congestion (d1-2) → Red hepatization (d3-4) → Gray hepatization (d5-7) → Resolution (d8 - wk 3)

What is red hepatization

RBC leak from increased vascular permeability in congestion phase → filling of RBC into lung

What is gray hepatization

RBC lysis and low capillary blood flow from compression → Color change from red to gray

H. influenza has what virulence factors

IgA protease and Endotoxin (LOS) → Impair ciliary movement

Hib virulence factors

LOS → Induce massive inflammation → Causes cherry red sign

Influenza A virulence factor

Hemagluttinin (HA) → Induce endocytosis

Neuraminidase (NA) → Cleave sialic acid to release mature virus → Destroy host cell to spread

Primary TB gross morphology

Ghon focus → White lesion around middle of lung

Ghon complex → Ghon focus + hilar lymph involvement with caseous necrosis

Ranke complex → Ghon complex with fibrosis and calcification

Secondary TB gross morphology

Miliary TB → Dissemination by blood

Norovirus characteristic

Gastroenteritis in adult and children → Outbreak in cruiseship

Rotavirus characteristic

Infant with red buttock and diarrhea

• Diarrhea is basically from lactose intolerance (Rota destroyed villi with lactase)

• Red buttock is from irritation

Adenovirus characteristic

Diarrhea with red eye (/+- lymphadenopathy)

C. jejuni characteristic

Bacterial diarrhea, Guillain Barre (ascending paralysis) from eating uncooked chicken or unpasteurized milk

Non typhoid salmonella spread by

Egg, chicken, reptiles

Typhoid salmonella characteristic

Constipation, rose spot, bradycardia, active in Peyer patch, inactive in gallbladder

Shigella characteristic

Bloody diarrhea; fecal oral transmission

ETEC characteristic

Increase cAMP → Increase water secretion → Watery noninflammatory diarrhea

STEC/EHEC (O157:H7) characteristic

Shiga like toxin that cause blood diarrhea; HUS cause anemia and kidney damage from eating undercooked beef

C. diff characteristic

Pseudomembraneous colitis from post Abx or fecal oral route

V. cholerae characteristic

Rice water stool (increased cAMP → increased water secretion)

H. pylori characteristic

Peptic ulcer, urease production increase stomach pH, inflammation without mucosal invasion; spread person to person

S. aureus food poisoning characteristic

Rapid onset, vomiting > diarrhea; from eating cream filled pastry, processed meat, salad

Giardia characteristic

Foul smelling floating stool after swimming in lake

Cryptosporidium characteristic

Diarrhea + HIV/AIDS, acquired from public pool

E. histolytica characteristic

Bloody diarrhea with RUQ liver abscess caused by contaminated water

Candida characteristic

Linear ulcer on esophagus + odynophagia

UPEC characteristic

Cystitis and pyelonephritis; has pili

K. pneumoniae characteristic

Nosocomial/complicated UTI; has thick anti-phagocytic capsule

P mirabillis characteristic

Struvite kidney stone, purple urine bag syndrome; high urease activity

S saprophyticus characteristic

Cystitis in sexually active female; novobiocin resistant

E. faecalis characteristic

Catheter associated; pili bind to catheter

P. aeruginosa characteristic

Opportunistic on soap; biofilm with blue green culture and grape smell

S pyogenes causes what skin conditions

Impetigo, erysipelas, cellulitis, cutaneous abscess, necrotizing fasciitis

Myonecrosis caused by

C. perfringens

Neonate cause of meningitis

Strep. Agalactiae

Cause of meningitis in children, adult and older adult

S. pneumoniae

HSV-1 characteristic

Encephalitis, common in temporal and inferior frontal lobe

Rabies characteristic

Retrograde axonal transport with Negri bodies

C neoformans characteristic

Common in HIV px, found in pidgeon poop

N. Fowleri characteristic

Penetrate cribriform plate → Primary amebic meningoencephalitis; found in warm still fresh water

T gondii characteristic

Infect pregnant women with cats, multiple ring enhancing lesion