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1
Q

Causes of inflammatory diarrhea

A
  1. EHEC
  2. EIEC
  3. Shigella
  4. Salmonella enterica and enteritidis
  5. Campylobacter jejuni
  6. Clostridium difficile
  7. Yersinia enterocolitica
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2
Q

Causes of non-inflammatory diarrhea

A
  1. ETEC
  2. EAEC
  3. EPEC
  4. Vibrio cholerae, parahemolyticus, vulnificus
  5. S. aureus
  6. Bacillus cereus
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3
Q

anaerobes

A
  1. bacteroides fragilis
  2. Preotella
  3. Clostridium perfringens, tetani, botulinum, difficile
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4
Q

Most infectious diarrheas are caused by?

A

viruses

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5
Q

Most likely cause of persistant diarrhea (lasting more than 10-14 days)?

A

parasite

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6
Q
  1. What should you start considering in chronic diarrhea?

2. Causes of this diarrhea?

A
  1. HIV

2. Mycobacterium avium intracellulare, CMV

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7
Q

acute diarrhea

A

3 or more loose stools per day lasting less than 2 weeks

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8
Q

chronic diarrhea

A

persists greater than 4 weeks

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9
Q

inflammatory diarrhea

A

“dysentery”, bloody diarrhea
WBCs, RBCs in stool
fever, small volume
COLON

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10
Q

non-inflammatory diarrhea

A

watery diarrhea
no cells in stool
afebrile, large volume
SMALL INTESTINE

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11
Q

Shared characteristics of Shigella, E. coli, Salmonella

A
  1. Gram ( - ) facultative anaerobic rods
  2. ferment glucose with acid production
  3. oxidase neg.
  4. reduce nitrates to nitrite (dipstick test)
  5. motile (NOT shigella)
  6. O and H antigens
    E. coli part of normal GI flora: don’t cause infection (lack PAI (pathogenicity associated islands)
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12
Q

Shigella

  1. lab
  2. transmission
  3. who gets it
  4. type of diarrhea
A

G ( - ) rod
1. nonmotile, non-lactose fermenting, does not produce H2S
2. fecal-oral, contaminated water/food
3. DAYCARE, migrant workers, travelers to developing countries, nursing homes
4. inflammatory
HIGHLY transmissible: low infectious dose

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13
Q

Shigella dysenteriae

A

epidemics in central/South America
can produce Shiga toxin (AB toxin)
HEMOLYTIC UREMIC SYNDROME

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14
Q

Shigella sonnei

A

US, mostly children

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15
Q

Shigella flexneri

A

2nd most common Shigella in US

most common worldwide

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16
Q

Shigella pathogenesis

A

resistant to acidic environment of stomach

  1. taken up by epithelial M cells
  2. proliferate intracellularly, escape into lamina propria and phagocytes by macrophages causing apoptosis
  3. inflammatory damage to epithelia allows invasion of cells
  4. spreads to adjacent cells via membrane bound protrusions (via FORMINS) that lyse membranes surrounding it, freeing it into new cell cytoplasm
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17
Q

Shigella

  1. Sx
  2. complications
  3. Tx
A
  1. self-limited diarrhea (starts watery and progresses to bloody in half), fever, abdominal pain (lasts about a week)
  2. reactive arthritis, urethritis, conjunctivitis, hemolytic uremic syndrome in toxin producing S. dysenteriae
  3. ceftriaxone, ciprofloxacin, azithromycin
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18
Q

Enterohemorrhagic E. coli (EHEC, STEC)

  1. lab
  2. transmission
  3. type of diarrhea
A 
1. can't ferment sorbitol
O157: H7 or non-O157:H7
2. inadequately cooked meat (HAMBURGERS), contaminated vegetables and milk, human to human
3. inflammatory
low infectious dose
HOSPITALIZATION in 25-50%
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19
Q

EHEC pathogenesis

A

SHIGA-LIKE toxin

LEE

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20
Q

EHEC

  1. Sx
  2. complications
  3. Dx
  4. Tx
A
  1. similar to Shigella: fever, cramps, watery diarrhea that becomes bloody (hemorrhagic colitis) within a day; lasts up to 8 days
  2. HUS, AKI
  3. SORBITOL-MACCONKEY agar, PCR or ELISA (detect Shiga toxin)
  4. SUPPORTIVE, avoid antidiarrheals and antibiotics
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21
Q

Enteroinvasive E. coli (EIEC)

  1. Sx
  2. transmission
  3. who
  4. pathogenesis
A
  1. similar to Shigella
  2. food/water, person to person
  3. young children in developing countries
  4. invades intestinal cell, multiplies intracellularly, extends into adjacent cells
    NO toxins
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22
Q

Salmonella

  1. lab
  2. type of diarrhea
A

Gram neg. rod

  1. non-lactose fermenting, produces H2S
  2. inflammatory
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23
Q

Salmonellosis pathogenesis

A
  1. attach to M cells
  2. type III secretion of proteins into M cells
  3. endocytosis
  4. enter lamina propr.
  5. inflammatory response
  6. kills macrophages
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24
Q

Salmonellosis

  1. transmission
  2. Sx
  3. complications
  4. treatment
A

S. enteritidis
1. DAIRY, MEAT, POULTRY, EGGS, REPTILES (TURTLES, LIZARDS), human to human
2. N/V, diarrhea, cramps, fever in some (lasts 304 days)
3. bactermia, endovascular infections, endocarditis, osteomyelitis, aortic plaques and bone protheses, reactive arthritis
Dx: stool culture
4. not required for healthy people 2-50 yrs, flouroquinolones (must test for susceptibility) for those at risk of disseminated disease

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25
Salmonella enterica 1. transmission 2. who
TYPHOID fever South-central Asia does NOT cause gastroenteritis 1. person to person (fecal-oral, infected food handler, contaminated food/water); FOODBORNE, HUMANS sole reservoir 2. children, young adults; POOR SANITATION
26
Salmonella paratyphi
illness similar to Typhoid fever | does NOT cause gastroenteritis
27
Salmonella enteritidis
Nontyphoid Salmonella causes SALMONELLOSIS FOOD POISONING
28
Which pts with Salmonellosis should be treated?
flouroquinolones 1. severe infection 2. atherosclerotic plaques 3. endovascular/bone protheses 4. immunocompromised 5. sickle cell disease
29
Typhoid fever pathogenesis
1. invade M cells 2. engulfed by macrophages in lymphoid tissue 3. disseminate to lymph nodes and RES then to blood: Sepsis can occur 4. proliferate in submucosa: hypertrophy of Peyer's patches can cause GI tract PERFORATION 5. chronic carriage can occur in biliary tract
30
Typhoid fever 1. first week 2. second 3. third 4. Dx 5. Tx 6. prevention
1. fever/chills, bacteremia; BRADYCARDIA 2. ROSE SPOTS, abdominal pain 3. hepatosplenomegaly, GI bleeding, perforation, secondary bacteremia 4. blood cultures: may require several days incubation 5. ceftriaxone, azithromycin, ciprofloxacin 6. vaccine
31
When would you not give ciprofloxacin for typhoid fever?
pt has been to an area with high rates of fluoroquinolone resistance such as SOUTH ASIA
32
Campylobacter jejuni 1. lab 2. transmission 3. Sx 4. Dx 5. Tx 6. complications
MOST COMMON bacterial enteric pathogen in developed countries TRAVELER's DIARRHEA 1. thin, spiral GNR 2. chicken, unpasteurized milk, contaminated water highly transmissible 3. watery diarrhea that becomes bloody in some, fever, cramps, self-limited 4. stool culture 5. only for severe disease; azithromycin, ciprofloxicin 6. GUILLAIN BARRE, ERYTHEMA NODOSUM, REACTIVE ARTHRITIS
33
Yersinia enterocolitica 1. lab 2. transmission 3. who
G (-) coccobacilli 1. BIPOLAR staining 2. pork, raw milk, contaminated water, pet feces 3. EUROPE
34
Yersinia enterocolitica 1. Sx 2. Dx 3. Tx
ILEUM, APPENDIX, RIGHT COLON: lymph node and Peyer patch hyperplasia 1. PSUEDOAPPENDICITIS, N/V, fever/diarrhea; extraintestinal: PHARYNGITIS, ARTHRALGIA, ERYTHEMA NODOSUM 2. stool culture 3. most don't need it
35
Clostridium difficile 1. transmission 2. pathogenesis 3. hypervirulent strands
``` anaerobic, G (+) rod SPORE 1. fecal-oral: hospital personal MOST common NOSOCOMIAL and ANTIBIOTIC associated diarrhea 2. Exotoxins A and B 3. NAP-1/027 ```
36
Clostridium difficile 1. Sx 2. Dx
1. watery diarrhea, cramps, fever, LEUKOCYTOSIS, PSEUDOMEMBRANOUS COLITIS, FULMINANT COLITIS, TOXIC MEGACOLON 2. PCR for toxins A and B, cell culture cytotoxicity assay (takes 2 days); EIA 3. metronidazole first line, severe first line: vancomycin recurrence: metronidazole 2nd recurrence: vancomycin other: fidaxomycin, fecal transplant
37
risk factors for C. diff
1. advanced age 2. multiple antibiotics: esp. clindamycin + penicillins; cephalosporins + fluoroquinolones 3. hospitalization 4. IBD 5. gastric acid suppression?
38
enterotoxigenic E. coli (ETEC) 1. transmission 2. Sx
major cause of TRAVEL'S DIRRHEA 1. contaminated food and water 2. watery diarrhea (1-5 days) 3. HEAT-LABILE TOXIN, HEAT-STABLE TOXIN
39
enteropathogenic E. coli (EPEC) 1. who 2. Sx 3. pathogenesis
1. children under 2, infants 2. watery diarrhea with severe vomiting and dehydration 3. attaching and effacing lesions and pedestal like structures: LEE
40
enteroaggregative E. coli (EAEC)
traveler's diarrhea | diarrhea in children, adults, HIV patients in developed and developing countries
41
uropathogenic E. coli (UPEC)
UTI Sx: frequency, dysuria, pyuria, suprapubic pain, cloudy urine, cramping, afebrile Dx: female: greater than 10^5 per ml; male: greater than 10^3 virulence: P fimbriae, PAP pili, capsule
42
Other E. coli infections (non-GI)
1. hospital acquired: sepsis 2. neonatal meningitis: K1 antigen 3. UPEC
43
Vibrio 1. lab 2. where found 3. transmission
``` curved (comma shaped) GNR motile, flagellum 1. oxidase pos. 2. SALTWATER, WARM MONTHS 3. SHELLFISH ```
44
Vibrio cholerae 1. transmission 2. location 3. antigen 4. pathogenesis
1. fecal contaminated drinking water: DISASTERS 2. Asia, Africa, S. America, Indian subcontinent 3. O antigen 4. mucinase, AB toxin O1 (divided into E1 Tor, Classic), O139 serotypes high infectious dose high mortality without Tx
45
Vibrio parahaemolyticus 1. location 2. Sx 3. complications 4. Dx 5. Tx
1. JAPAN, rare in US (Gulf, Pacific) 2. watery diarrhea, N/V, cramps, fever, self-limited 3. bacteremia can occur in underlying conditions like liver disease; wound infections (severe in those with liver disease, DM, alcoholism: can lead to cellulitis) 4. culture 5. volume repletion; in severe cases: doxycycline
46
Vibrio vulnificus 1. Sx 2. complications 3. Dx 4. Tx
1. diarrhea, severe SKIN and soft tissue infections 2. septicemia in immunocompromised 3. culture 4. Doxy plus cefotaxime or ceftriaxone
47
factors predisposing to V. cholerae infection
1. poor sanitation 2. malnutrition 3. overcrowding 4. inadequate medical services
48
Vibrio cholerae 1. Sx 2. complications 3. Dx 4. Tx 5. prevention
1. watery diarrhea, dehydration, RICE WATER stools (flecks of mucous, smells fishy), vomiting 2. CARDIAC and RENAL failure, ACIDOSIS, HYPOKALEMIA NO abdominal pain 3. clinical suspicion, selective media: TCBS, TTGA, MacConkey agar (colorless) 4. VOLUME REPLETION; antibiotics adjunctive: tetracycline, erythromycin, azithromycin, ciprofloxacin; Oral rehydration salts 5. clean water, sanitation; oral vaccine in endemic areas
49
Bacillus cereus 1. transmission 2. pathogenesis 3. Sx
gram (+) bacilli 1. FRIED RICE 2. SPORE, diarrheal enterotoxin, emetic toxin 3. diarrheal syndrome, emetic syndrome
50
S. aureus
1. enterotoxin (heat-stable), superantigen 2. food handled foods left at room temperature: dairy produce, meat, egg, salad, POTATO SALAD 3. within 1-6 hrs of ingestion: N/V, cramps, fever/diarrhea in minority; lasts 24 hours or less
51
Where are anaerobes prevalent?
gut microbiome, oral cavity, skin, colon, female genital tract ex: Bacteroides, Clostridia
52
Why are anaerobes inhibited by oxygen?
no superoxide dismutase (SOD) or catalase
53
anaerobic infection
lack SOD and catalase STINK need special transport and culture ABSCESSES: polymicrobial and reflect normal flora in that site
54
Bacteroides fragilis 1. where found 2. predisposing factors 3. pathogenesis 4. Sx 5. Dx 6. Tx
GNR 1. predominant organism in colon, found in vagina 2. surgery, trauma, chronic disease 3. capsule (role in abscess formation) 4. pelvic/peri-rectal abscesses, lung abscess, peritonitis, baceremia, infected decubitus ulcers; diarrhea (enterotoxin strain) 5. anaerobic cultures 6. metronidazole, carbapenem, beta lactic with beta-lacatkase inhibitors resistant to penicillin
55
Prevotella melaninogenica
G (-) coccobacillus 1. oral cavity, GI tract, vagina, nasopharynx OPPORTUNISTIC 2. oral/periodontal/pulmonary abbesses; chronic otitis, sinusitis
56
Clostridium 1. where found 2. pathogenesis
G (+) rod SPORE, ANAEROBIC 1. colon 2. exotoxins, hydrolytic enzymes
57
Clostridium perfringens 1. Sx 2. who 3. transmission
BOXCAR G (+) bacilli 1. gas gangrene, food poisoning: watery diarrhea, cramps, minimal vomiting, resolves in 24 hrs 2. psych inpatient facilities 3. soil; meat, poultry, gravy
58
Clostridium tetani 1. transmission 2. pathogenesis 3. Sx 4. Tx
1. wound (nail); soil; neonatal from circumcision or contaminated umbilicus 2. AB neurotoxin 3. spastic paralysis: trismus, risus sardonicus, opisthotonos, exaggerated reflexes, respiratory failure 4. wound debridement, HTIG; metronidazole or penicillin, active immunization with tetanus toxoid (don't have immunity after recovery) high mortality
59
Clostridium botulinum 1. types 2. pathogenesis 3. Sx of food borne 4. Sx of infant 5. Tx
1. foodborne: CANNED FOOD, FISH; infant: RAW HONEY, spores in CARPET; wound; inhalational (bioterrorism), iatrogenic 2. AB toxin 3. symmetric descending flaccid paralysis, nausea, dry mouth, dysphagia, diarrhea, blurred vision, respiratory failure 4. floppy baby syndrome: constipation followed by weakness, feeding difficulty, descending hypotonia, drooling, anorexia, irritability, weak cry 5. MECHANICAL VENTILATION, HORSE ANTI-TOXIN for those over 1 year of age; BIG-IV; penicilin or metronidazole (NOT for infant botulism)
60
When are antibiotics recommended for C. botulinum?
wound botulism | NOT for infant botulism: could increase toxin release
61
H. pylori 1. transmission 2. pathogenesis 3. Dx
``` slender, curved GNR motile, microaerophilic 1. gastric secretion, fecal-oral 2. VacA, PAI, Cag, urease 3. endoscopy, stool antigen, urea breath test, serology ```

GI (12 decks)

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