pathogenic bacteria-aerobic

gram negative cocci-neisseria
gram negative bacilli-enterobacteriaceae

gram negative diplococci
facultative aerobe
catalase +
outer membrane has LOS not LPS, lacks O antigen-causes ciliary loss, mucosal cell death
LOS is an endotoxin that looks like host cell membrane
obligate human pathogen, can't live outside host

pilli for attachment to urethra and cervix
IgA protease
antigenic variation
beta lactamase
COS causes inflammation, damage to tissue
women-asymptomatic
men-symptomatic
spread thru genital secretions, newborns infected thru birth
co-infection with chlamydia, syphillis
no toxins
Opa protein promote adherence

spread via droplets/close contact
pilli-attach to nasopharyngeal cells
Opa
IgA protease
capsule-enhances host defense in bloodstream
nasopharyngeal carriers-asymptomatic

gram stain and culture of purulent exudate
beta lactamase
chromsomal mediation mutate DNA gyrase and efflux pumps
antigen diversity prevents vaccine

gram stain and culture of CSF and blood
no beta lactamase
vaccine available against common capsule
empiric therapy likely due to seriousness of illness

lost neisseria
strictly aerobic
causes sinusitis, otitis media, bronchitis, CAP
beta lactamase

GI tract of humans/animals
gram negative rods
endotoxin/LPS
ferment glucose, reduce nitrates, catalase+, sometimes flagella for motility

gram - rod
O: Outer membrane LPS
K:polysaccharide Kapsule
H:flagella
most abundant facultative anaerobe
endogenous infection-UTI
exogeneous infection-gastroenteritis

capsule
pilli
endotoxin
exotoxin

colonization factor antigen Cfa, pilli adhere to epithelial cells
plasma encoded heat labile toxin (LT) and heat stable toxin (ST)
watery diarrhea

LT binds to GM1 ganglioside, toxin activates adenylate cyclase increases cAMP
ST activates guanylate cyclase increases cGMP
no visible damage to small bowel

does not produce toxins
virulence factors-Bfp, Intimin
Bfp-bundle forming pilli
Intimin-adhesin
1.Adhere to mucosal cells of small intestine via Bfp
2.Bacteria secretes Translocated intimin receptor (Tir) into mucosal cells
3.Intimin binds to Tir
4.Formation of filamentous actin pedestals

loss of microvilli in small intestine-loss of absorption, A/E lesion: attaching and effacing lesions
resource poor infants watery diarrhea

e coli ferments lactose and glucose

verotoxin
toxin is bacterophage encoded, transduction
binds to rRNA in 60S disrupts protein synthesis
most common strain, transmits from person to person

adhere to small and large intestine
induce A/E lesions
toxin destroys mucosa
causes hemorrhagic colitis, hemolytic anemia, thrombocytopenia, renal failure
bloody diarrhea
from undercooked food, unpasteurized milk

acute uncomplicated UTI
e coli most common uropathogen
virulence due to hemolysin, lyses RBCs leads to cytokine release
also with pilli-facilitates adherence

outer membrane O antigen
flagella H
Kapsule K
non-lactose fermentors unlike e coli

acid tolerance response genes
endotoxin
pathogenicity islands-invasion proteins

gastroenteritis-no fever
extra intestinal infection-persistent bacteremia
enteric fever-thyphoid
-Human-specific reservoir/transmission; chronic carrier state
-Following penetration to the lamina propria, bacteria enter the bloodstream à transient bacteremia
-Bacteria multiplies in macrophages of liver, spleen, lymph nodes à septicemia à fever
-Invasion of gallbladder and kidney, and 2ndary invasion of the intestinal mucosa
-Diarrhea, hemorrhage, perforation of organs

isolated from feces
serology-agglutination by antiO antibodies present in patient sera, typhi serotype produce Vi antigen

bacterial dysentary
water then bloody diarrhea
serological classfication based on O antigen of LPS
s. dysenteriae-produce shiga toxin, tissue invasion
s. flexneri-tisseu invasion, no toxin
s. sonnei-watery diarrhea, tissue invasion, no toxin
no animal reservoir
spread via oral-fecal route

endotoxin causes inflammation
acid tolerance response genes
shiga toxin=60S ribosomal unit
intracellular spread protein
invasion plasmid antigen

non-lactose fermentor
presence of leukocytes in diarrhea
agglutination assay using patient sera
no vaccine