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177 Cards in this Set
- Front
- Back
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culture medium for H pylori
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Skirrow agar
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how H pylori move through the mucus
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flagella and mucinase
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where H pylori adhere
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at the intracellular junction of the enteric epithelial cells
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2 virulence factors of H pylori
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VacA
cag pathogenicity island genes |
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effects of H pylori virulence factors
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they inc IL8 and cause mononuclear cell infiltration
this inc erosion of the gastric mucosa |
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Tx for H pylori
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Metronidazole or tetracycline with clarithromycin and omeprazole
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Sx--> Abdominal pain that has been worsening for a few weeks
- often improves immediately after a meal or after taking antacids occasional heartburn no fevers, nausea, vomitting, diarrhea, or bloody stool streesful conditions at work or home PE→ midepigastric tenderness |
H pylori
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feat of viridans strep
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resistant to optochinin
alpha-hemolytic or non-hemolytic |
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causes of native valve endocarditis
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viridans strep
enterococci HACEK |
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how viridans strep adhere to heart valves
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fibronectin-binding proteins
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how staph adhere to heart valves
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clumping factor
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bugs assoc with IE of prosthetic heart valves
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staph epidermidis
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PE findings in pt with IE
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janeway lesions of the palms or soles
osler nodes(finger or toepad) roth spots(retinal hemorrhages) plinter hemorrhages of the nail bed |
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DOC for IE by viridans strep
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IV penecillin G
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low-grade fever, night sweats, fatigue for 3 weeks, Hx of a heart murmur, recent dental procedures with no abx prophylaxis, conjunctival petechiae
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viridans strep
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how campylobacter fetus can evade IS
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they have a proteinacous capsule
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major virulence factor of C. jejuni
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flagella
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test that differentiates the different species of campylobacter
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nitrate reduction test
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most common cause of bacterial diarrhea
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C jejuni
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route of transmission of C jejuni
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improper food handling, with chicken being most common
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cause of damage in C jejuni
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distending toxin
neutrophilic invasion of the lamina propria and jejunal epithelium heat-labile cholera-like toxin |
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dz assoc with C jejuni
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reactive arthritis
Guillain-Barre |
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Tx of C jejuni
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rehydration
erythromycin or quinolones in the elderly |
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Symptoms
Severe abdominal pain/cramping and diarrhea Bloody bowel movement Eating chicken |
C jejuni
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feat of Salmonella typhimurium
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GN rods
motile facultative anaerobes dont ferment lactose |
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Ags of Salmonella typhimurium
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cell wall O Ag
flagellar H Ag |
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how H Ag of Salmonella typhimurium acq variation
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phase variation via DNA rearrangement
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feat of Salmonella typhimurium metabolism
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Dont ferment lactose
produce acid during glucose fermentation reduce nitrates don't carry cytochrome oxidase |
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reservoirs of Salmonella typhimurium
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poultry, eggs, and dairy products
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how Salmonella typhimurium adhere
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they adhere to the distal ileum by fimbriated adhesins
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Tx of Salmonella typhimurium
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fluoroquinolones are only needed for AIDS, neonates, and elderly
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Symptoms
Low grade fever, abdominal cramps, vomitting, and diarrhea |
Salmonella typhimurium
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feat of Salmonella typhi
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GN facultative anaerobes
not a lactose fermenter encapsulated with K(aka Vi Ag) Ag |
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incubation period of Salmonella typhi
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3days to 3 months
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how Salmonella typhi adhere
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M cells
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Tx for Salmonella typhi
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Chloramphenicol, ampicillin, or TMP/SMX
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Symptoms
3day Hx of shaking chills, high fever, headache, abdominal pain, and generalized weakness Diarrhea Visiting a foreign country PE→ diffusely tender abdomen, hepatosplenomegally, erythematous maculopapular lesions(rose spots) Thrombocytopenia, leukopenia(Inc percent of monos) |
Salmonella typhi
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serogroup A shigella
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dysenteriae
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serogroup B shigella
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flexneri
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serogroup C shigella
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boydii
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serogroup D shigella
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sonnei
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feat of shigella
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nonmotile
nonencapsulated facultative anaerobes |
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culture medium for shigella
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Hektoen agar
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shigella species that ferments lactose
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sonnei
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feat of S. sonnei
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identified by their O Ag because they lack flagella H Ag
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most common shigella in USA
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sonnei
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incubation of shigella
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1-3 days
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how shigella gain entry to body
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invade M cells of the intestine and are taken up by macrophages in the lamina propria
the invading PMNs breakdown tight jxns between cells and allow spread |
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what is needed for cell to cell spread of shigella
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L-CAM and finger-like projections of infected cells
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dz caused by shigella toxins
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HUS and TTP
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DOC for shigella
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TMP/SMX
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Symptoms
Acute onset of fever, crampy abdominal pain, and watery diarrhea. Tenesmus and mucus with a tinge of blood in the stool Ulcers and an erythematous friable mucosa on imaging |
Shigella flexneri
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feat of EHEC
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indole-positive
lactose-positive sorbitol-nonfermenting isolate |
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major vesicles of EHEC
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ground beef and unpasteurized milk
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where EHEC adhere
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the brush border of the intestinal epithelium
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feat of enterocytes inf with EHEC
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prolif of actin below site of attachment
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physical feat of V cholerae
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curved GN rods
highly motile with a single flagella |
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feat of cholera metabolism
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nonspore forming
oxidase positive facultative anaerobes |
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culture medium for cholera
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thiosulfate-citrate-bile-sucrose agar so normal flora dont grow
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feat of cholera that cause epidemics
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those that agglutinate in 0:1 antiserum
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cholera type in current ongoing pandemic
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El Tor biotype
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type of cholera in the gulf coast and that is assoc with shellfish
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non-0:1 biotype
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feat of cholera toxin
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AB type ADP-ribosylator
causes inc Cl- excretion and dec Na+ absorption |
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what is coregulated with the toxin gene in cholera
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the long filamentous pili used for attachment
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Tx for cholera
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IV or oral rehydration
Doxycycline |
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Symptoms
Travel to india, sudden and profuce watery diarrhea with rice water appearance, vomitting, muscle cramps, and dizziness |
Vibrio cholerae
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feat of staph toxins in food poisoning
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they are stable at boiling temps
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Symptoms
Ill soon after meal, N&V, crampy abdominal pain, ate precooked ham that was served cold |
Staph aureus food poisoning
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feat of C botulinum
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GP, spore forming rod
obligate anaerobe produce heat-labile neurotoxin |
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food assoc with C botulinum
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honey and corn syrup
home-canned fruit sausage fish with pH >4.6 |
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how botulism toxin is brought into neurons
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translocation
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feat of botulism toxin
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zinc-metalloprotease that cleaves components of the neuroexocytosis apparatus
irreversibly prevents release of Ach |
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Tx for wound botulism
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Penecillin or metronidazole
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Tx for botulism
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trivalent equine antitoxin serum(isn't effective after the toxin is internalized)
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Symptoms
Decreased activity, decreased oral intake, upper airway congestion, general irritability, no Hx of fever or vomitting PE→ listless, dry oral mucosa, sluggish pupillary response to light, mild abdominal distention with hypoactive bowel sounds, significant hypotonia |
Clostridium botulinum
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feat of C. dif
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anaerobic, GP, spore-forming rods
produce toxin A and toxin B |
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abx assoc with C dif
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clindamycin
cephalosporins ampicillin |
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feat of A and B toxin of C dif
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they bind GTP-binding proteins in the Rho family
they are inactivated by glycosylation(causes depolymerization of actin) |
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Tx for C dif
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metronidazole
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Symptoms
Fever, abdominal cramping, and frequent diarrhea, recent Abx use, no family members with similar Sx PE→ decreasedturgor of the skin and dry oral mucosa |
C dif
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feat of rotavirus
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non-enveloped RNA virus
nucleocapsid made of 2 concentric shells 11 segments to genome of dsRNA |
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family that rotavirus belongs to
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Reovirus
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most common cause of gastroenteritis around the world
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viruses(rotaviruses and noroviruses)
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most common cause of dehydrating diarrhea in infants <3yo
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rotavirus
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time when rotavirus inf is most common
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winter
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what commonly occurs with rotavirus inf
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RTI
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defense against rotavirus
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IgA
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what a rotavirus inf
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mature villus tips of the small intestine
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Symptoms
Young child, vomiting, watery diarrhea, fever, rapid onset PE→ mucous membranes dry, listless, and febrile, bowel sounds normal |
rotavirus
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what family does norovirus belong to
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Caliciviridae family
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feat of norovirus
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single stranded RNA
spherical, nonenveloped 27nm virus with positive sense, polyadenylated RNA |
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route of transmission of norovirus
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fecal-oral route year round
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incubation period for norovirus
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24-48 hrs
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feat of small intestine in norovirus inf
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There is shortening and atrophy of the villi, crypt hyperplasia, and infiltration of the lamina propria by neutrophils and macrophages
There is dec carb absorption along with dec levels of brush border enzymes |
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Symptoms
N&V, diarrhea, headache, fever, and myalgias PE→ abdominal pain, nausea, no blood in stool |
norovirus
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feat of the trophozoite in E. histolytica
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single nucleus with a central karyosome and uniformly distributed peripheral chromatin
resist complement |
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feat of the cysts in E histolytica
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spherical with 4 nuclei
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feat that differentiates E histolytica and dispar
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histolytica has erythrophagocytosis
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ameba other than E histolytica that causes diarrhea
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Dientamoeba fragilis
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mode of transmission of E histolytica
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ingestion of mature cysts
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receptor that allows for E histolytica to adhere to the intestine
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lectin-binding receptor
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how E histolytica replicate
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binary fision
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virulence factors of E histolytica
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cytotoxins that lyse epithelial cells and PMNs
cysteine proteases that degrade collagen and elastin |
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DOC for E histolytica
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metronidazole
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Hx of fever, chills, leukocytosis, RUQ pain, and enlarged liver
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amebic liver abscess
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what should be avoided in E histolytica inf
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antimotility agents because they inc risk of invasive pathogens
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Symptoms
Intermittent diarrhea and tenesmus with blood and mucus visible in the stool Imaging→ multiple small hemorrhagic areas with ulcers |
E histolytica
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feat of the cysts in Giardia
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they have 4 nuclei
encased in a thin wall composed of N-acetylglucosamine |
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feat of the trophozoites in Giardia
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2 ant nuclei
pear shaped with a convex dorsal surface flat ventral surface with a sucking disk 4 pairs of flagella |
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common carriers of Giardia
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humans, dogs, and beavers
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how giardia adhere to brush border enterocytes
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their ventral disk with contractile proteins
receptor ligand interaction mediated by lectin proteins |
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how giardia trophozoites multiply
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binary fission
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pathology assoc with giardia inf
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the disrupt brush border by microvilli injury causing villus atrophy(via proteinase or mannose-binding lectin)
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Tx for giardia
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metronidazole
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Symptoms
Sustained diarrhea, nausea, flatulence, anorexia, watery diarrhea that becomes greasy and foul smelling, bloating |
Giardia lamblia
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bug that exists as oocyst
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Cryptosporidium
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intracellular parasite
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Cryptosporidium
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stain for cryptosporidium
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Auramine-rhodamine
modified acid fast stain |
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unique feat of cryptosporidium
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they can do their entire life cycle in the intestine
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site most heavily inf by cryptosporidium
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jejunum
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cause of diarrhea in cryptosporidium
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impaired absorption and inc PG synthesis
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Symptoms
AIDS pt with prolonged diarrhea, WL |
Cryptosporidium parvum
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largest intestinal nematode
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Ascaris lumbricoides
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feat of lumbricoides eggs
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they are bumpy on their coat
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length of time ascaris lumbricoides eggs must mature in soil
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30 days
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most commonly inf pts with Ascaris lumbricoides
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kids 3-8yo
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route of transmission of Ascaris
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uncooked produce
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pathogenesis of Ascaris
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they are ingested, invade the intestinal wall, enter the portal circulation, they are carried to the lungs, then they penetrate the alveolar walls, then they are swallowed after maturing for 10-14 days
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response to Ascaris inf
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Th2 response with eosinophilia
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DOC for Ascaris
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Mebendazole
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Symptoms
Hx of nausea, poor apetite, abdominal pain. No recent bowel movements PE→ distention of the abdomen and mildly tender Eosinophilia |
Ascaris lumbricoides
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where Strongyloides live
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the mucosa of the duodenum and jejunum
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diagnostic feat of Strongyloides inf
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prominent genital primordium
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mode of transmission of Strongyloides
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filariform larvae live in the soil of tropical regions and they can penetrate intact skin
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where rhabditiform larvae of strongyloides can become filariform larvae
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in the intestinal lumen
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how strongyloides cause reinfection
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they reenter through the skin of the perianal region
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DOC for Strongyloides stercoralis
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Ivermectin
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Symptoms
Hx of worsening diarrhea, abdominal pain, and fevers. Itchy rash over buttock and groin. WL PE→ erythematous maculopapular rash Eosinophilia |
Strongyloides stercoralis
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proglottid that carries the eggs of Echinococcus granulosus
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gravidad
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organism that causes hydatid cyst disease
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Echinococcus granulosus
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what is the carrier of the larval stages of Echinococcus granulosus
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dogs
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how long the larvae of Echinococcus granulosus mature inside of their animal carrier
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32-80 days
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organ most infected by Echinococcus granulosus
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the liver
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what causes alveolar hydatid disease
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larval stage of Echinococcus granulosus
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DOC for Echinococcus granulosus
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albendazole
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Symptoms
Sensation of fullness in RUQ, contact with sheepdogs Cysts on imaging No profound eosinophilia |
Echinococcus granulosus
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bug that lives in the venoud plexus near the urinary bladder and ureters
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Schistsoma haematobium
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bug that lives in the inf mesenteric art
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Schistsoma mansoni
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bug that lives in the sup mesenteric vein of both large and small intestine
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Schistsoma japonicum
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worms that remain in pairs even after mating
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Schistsoma mansoni
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Infection is caused by penetration of intact skin with infective cercariae
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Schistsoma mansoni
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bug assoc with snails
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Schistsoma mansoni
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type of reaction caused by Schistsoma mansoni
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granulomatous reaction
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DOC for Schistsoma mansoni
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Praziquantel
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Symptoms
Long term Hx of abdominal pain, diarrhea, nausea, and vomitting. Immigrant from a developing country PE→ enlarged liver and/or spleen Eosinophilia |
Schistsoma mansoni
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feat of HAV
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Small(27-32nm) RNA virus
Single stranded(polyadenylated) and positive sense(RNA polymerase is carried with the virus) The virus has an icosahedral capsid without a lipid envelope |
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unique feat of HAV
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only hepatitis virus that can be cultivated in cell cultures
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route of transmission of HAV
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fecal-oral route
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incubation period of HAV
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30days(shorter than most hepatitides)
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cause of liver damage in HAV inf
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CTL activation
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when does IgM HAV Ab present
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5-10 days before the onset of symptoms
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Symptoms
Fever, jaundice with dark yellow urine, pale colored stools. The sight of food makes you nauseated PE→ hepatomegaly, but no splenomegaly. Icterus |
HAV
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feat of HBV
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42nm double shelled DNA virus
- the DNA is circular and incomplete - they have a lipid envelope |
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family of HBV
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Hepadnaviridae
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primary component of the HBV vaccine
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HBsAg
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mode of transmission of HBV
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sexual and blood contact
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incubation period of HBV
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45-210 days
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feat of HBsAg
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the first marker to appear
- it disappears by month 3 when the pt has complete recovery - anti-HBs become detectable in pts that don’t become chronically infected |
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feat of chronic HBV inf
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The HBV genome can integrate into the hepatocyte chromatin and remain latent
- this hide and infiltrate strategy leads to chronic disease o HBsAg and IgG HBcAb remain persistently detectable - Chronic persistent hepatitis is when there are no symptoms(except for maybe hepatosplenomegaly) - Chronic active hepetitis is when there is disease and jaundice o They will have elevated levels of HBeAg |
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Tx for HBV
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INF-α, lamuvidine, or adefovir are used in chronic infection
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Symptoms
Fever, jaundice, generalized itching, IV drug use PE→ jaundice, hepatosplenomegaly, scleral icterus Inc lymphs, ALT, and AST |
HBV
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family and genus of HCV
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Hepacivirus genus and Flaviviridae family
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Feat of HCV
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Enveloped virus(50nm) with an icosahedral capsid, containing a single stranded, polyadenylated, positive sense RNA genome
- replication of the genome req viral RNA polymerase |
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genotype of HCV in USA
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genotype 1
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incubation period of HCV
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14-180 days(6-7 weeks avg)
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Dx feat of HCV
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The elevation of the ALT is the most characteristic feature and it precedes ant-HCV seroconversion
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Tx for HCV
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INF and ribavirin can be used for chronic disease
- pegylated INF and ribavirin together are the DOC |
