gram - pathogens of mucosal surfaces pt. 2 Flashcards
invasive bacterial pathogens
salmonella
shigella
toxin producing bacterial pathogens
vibrio
entertoxigenic e coli (ETEC)
hybrid pathogens (btwn invasive and toxin producing)
enterohemorrhagic e coli (EHEC)
enteropathogenic E coli (EPEC)
traits of invasive bacterial pathogens
invade lg intestine
sm vol of bloody stool
leukocytes in stool
tissue ulcerations
traits of toxin producing bact
invade sm intestines
copious amounts of watery stool w/ no blood leukocytes or tissue damage
traits of hybrid bacterial path
invade lower sm or upper lg intestines
colonization causes attaching and effacing intimate adherence pattern (attaching and effacing lesion)
lesions causing blood stool (and urine w/ EHEC)
types of vibrio
cholerae - diarrhea
parahaemolyticus - diarrhea
vulnificus - tissues and blood
alginolyticus - tissues and blood
virulence factors of v. cholerae
flagella
pili to adhere to mucosal tissue (activated by reduced ion levels caused by shift from saltwater to body
cholera toxin - phage encoded
how does heat labile toxin differ from heat stable toxin?
heat labile activates AC causing an inc. in cAMP
heat stable toxin activates GC which causes and inc. in cGMP
traits of ETEC
responsable for traveler’s diarrhea
lg infectious does
colonization factor antigens on fimbrae help adhere to mucosal tissue
produces heat-labile toxin and heat-stable toxin
how do you treat toxin prod bact path
oral rehydration
antibiotics tetracyclines or fluoroquinolones
traits of EPEC
prevalent in newborns noninflammatory diarrhea distal sm intestine lg infectious dose no traditional exotoxins
steps of intimate adherence by EPEC and EHEC
1 bundle forming pili assist in adherence
2 type III secretion system injects Tir into host cell
3 Tir binds to intimin on E coli resulting in pedestal formation
how does EPEC cause diarrhea
no toxin, so malabsorption due to microvilli disruptions or epithelial tight junctions
how does EHEC cause diarrhea?
same way as EPEC (b/c has set of its genes) plus it makes a toxin that leads to hemolytic uremic syndrome
EHEC traits
e coli O157H7 is most common
reservoir = cattle
makes effacing lesion
produces shiga-like toxin
diagnosis of EHEC
bloody stool and edema of ascending colon
also shigalike toxins present
no sorbitol fermentation
treatment of EHEC
no antibiotics
rehydration
dialysis if hemolytic uremic syndrome
what’s cystitis?
inflammation of bladder
traits of uncomplicated UTI
mainly caused by e coli
normal defense mech are intact
no recent hospital admissions
limited to lower urinary tract
traits of complicated UTI
mainly caused by klebsiella, p. aeruginosa and serratia
structural abnomality in urinary tract
recently in hospital
spread to kidneys
natural defenses of urinary tract
voidance of bladder peristalsis ureterovesicle valves mucous layer microflora pH
traits of uropathogenic E coli (UPEC)
adhere to uroepithelial cells through fimbriae (can case acute cystitis, and pyelonephritis)
production of aerobactin and hemolysin (assoc w/ pyelonephritis)
genetically linked to recurrent disease
traits of proteus mirabilis
can cause uncomplicated UTI that’s more severe than w/ e coli
proteus virulence factors
flagella adhesin on fimbriae specific for urinary ep hemolysins IgA protease urease (raises pH of urine)
diagnosis of UTI
hard to tell which bact
alkaline urine/urease production = proteus
treatment of UTI
antimicrobials esp trimethoprim sulfamethoxazole
klebsiella virulence factors
pili (type 1 = urinary tract and type 3 = repiratory tract)
enterotoxine similar to ST and LT (induces diarrhea)
aerobactin (iron sequestering prot)
large antiphagocytic capsule
traits of helicobacter pylori
most prevalent gram (-) GI bug oral to oral transmission slow bact only in mucous overlying mucous secreting cells of stomach no animal reservoir
virulence factors of helicobacter pylori
produces urease to inc pH
inflammatory effector molecules cause IL-8 production
cytotoxin
down regulate somatostatin producing D cells which causes inc. gastrin production (causes cell mutation and ulcers)
treatment for helicobacter pylori
intense w/ many side effects
first line and second line ea. have a proton pump inhibitor and antibiotic cocktail
