febrile invasive diarrhea Flashcards Preview

Micro > febrile invasive diarrhea > Flashcards

Flashcards in febrile invasive diarrhea Deck (135):
1

most communicable bacterial diarrheal agent

Shigella

2

Shigella
what color on MacConkey?

G- bacilli, non-motile non-lactose fermenting (non-coliform):
white on MacConkey agar

3

Shigella: extra or intracellular?

intracellular: can invade and multiply in colonic epi cells-->cause inflammatory dis. of large bowel

4

Shigella diarrhea or dysentery?

either or both

5

Shigella: four species groups

S. dysenteriae Group A (most sev.)
S. flexneri, Group B
S. boydii, Group C
S. sonnei, Group D (least severe)

6

in US Shigella most common affects ??

what S. spp in US??

kiddos (1-4yo)
all age groups are susceptible
S. sonnei (D) and S. flexneri (B)

7

Shigella reservoir
carry org how long after recovery?

only humans
1 mo

8

Shig: low or high inf. dose?


transmitted how?

low (10^2)
secondary attack rate is high

fecal-oral route, direct person-person, vehicles (food and water), and mech. vectors (flies)
-so basically anything, sneaky Shigella

9

Shigella assoc. with age/gender/season

kiddos 1-4
no gender or season assoc.

10

Shig risk factor

poor personal hygiene

11

Shigella is a biphasic descending illness:
cause bacteremia?

diarrhea followed by dysentery
does NOT cause bacteremia

12

after ingested, Shig orgs reach ?? where they initially multiply and ?? which does what ??

small bowel
release toxin which stimulates active secretion of water and e-lytes from jejunum

13

Shig proceeds to the ?? where it invades/penetrate via the ?? then moves cell-cell going on to multiply in the ??

colon
penetrates via follicle associated M cells
mucosal epi cells (enterocytes) (facultative IC)

14

Shigella in the enterocytes results in ??

inflammatory response, bleeding, sloughing of cells, formation of abscess and ulcers

15

what type of Shig can cause HUS

S. dysenteriae type 1

16

Shig virulence factors is dependent on ??

temp reg
prod. >=37 degrees

17

Shig virulence factors: enterotoxins

ShET1 and ShET2

18

Shig virulence factors: surface Ags

induce "parasite directed" endocytosis into M cells and spread btw epi cells

19

Shig virulence factors: OspE proteins:
how do they increase bac. cell-to-cell spreading and promote colonization?

highly conserved among EHEC, EPEC, and Salmonella
reinforce host cell adherence to basement mem by interacting with *integrin-linked kinase (ILK)* -->which suppresses epi detachment

20

Shig vir factors: Shiga toxins (Stx)
only what Shig species?

cytotoxins
only S. dysenteriae type 1

21

Shig Stx acts at level of ?? causing ??

can also ??

60S ribosome causing irreversible inactivation of EF-1 and INF-y
activate apoptosis in macros (think EHEC and STEC)

22

Shig presentation
triad of sev. dysentery

variable: mod diarrhea to sev. dysentery:
triad of cramps, tenesmus (painful straining), and frequent small volume bloody mucoid discharge

23

Shig onset?
initial symptoms ??? for this spp ???

incubation for 24-72 hrs (1-3 days)
*fever*, systemic manifestations, cramps, vomiting, diarrhea (watery) for S. sonnei (most common in US)

24

Shig dysentery after initial symptoms characterized by ??

sev. cramps most common in ??

*blood, mucus, PMNs in stool*
fever, cramps tenesmus
kiddos and oldies

25

Shig causes daily loss of ?? which can result in ??

serum protein (200-300 mL) in feces-->depletion of nitrogen stores-->malnutrition, growth stunting

26

complications of Shig

long term carrier state!
reactive arthritis
HUS
autoimmune disease

27

reactive arthritis most common in ind. with ??
presents how??
what occurs ??

HLA-B27
polyarthritis: mild-->severe, may last days
polyclonal B cell activation

28

HUS occurs in Shig due to ?? only produced by ??
triad??

shiga toxin (Stx)
S. dysenteriae, type 1
triad: microangiopathic hemolytic anemia, thrombocytopenia, acute renal failure

29

Shig immunity

spp. specific
can turn off host prod. of anti-bacterial peptides

30

Shig dx
pres?
in feces?


bloody, mucoid stools and fever
*fecal leukocytes, PMNs, and RBCs*

31

Shig dx
Cx?
serology?


need selective media (MacConkey-white)
done to ID spp

32

Shig dx: ??? can be useful in ddx bacillary dysentery from amoebic dysentery

sigmoidoscopic examination
bacillary: diffuse ulcer pattern
amoebic: focal ulcers

33

Shig ddx

Salmonella, yersinia, EIEC, campylobacteria, amoebia
less common: EHEC and C. diff
basically all other agents of febrile diarrhea

34

Shig ddx EIEC: how similar?

sim. pathogenesis, virulence factors, disease manifestations

35

Shig vs. amebic dysentery: see ??? but no ??? with amebic

RBCs and trophozites but few if any PMNs

36

Shig tx
consider abx for it will ?? and ??

BUT

fluid replacement
reduce disease duration from 5-7 days to 3 days
AND eliminate carrier state
BUT abx resistants (plasmid-mediated) is a problem

37

Shig prevention

wash yo hands!
community recognition, participation, education on hand washing, esp for kiddos
vaccine in development

38

commonalities of Campy, Yersi, Salmonella

G- (only Campy ox +)
zoonosis
all invasive and can cause a bacteremia: Salm>Yersi>Campy(worst!)

39

virulence factor for invasiveness of Campy, Yersi, Salmonella

outer membrane component

40

Campy, Yersi, Salmonella are all

facultative IC pathogens in macrophages

41

dx Campy, Yersi, Salmonella via
if fever??

Cx and micro.examination of feces for *fecal leukocytes*
if fever, *blood cx*

42

Campy, Yersi, Salmonella tx

supportive unless substantive fever-->means extra intestinal disease (systemic?) so give abx

43

complications of Campy, Yersi, Salmonella ??

reactive polyarthritis assoc. w. HLA B27 and *pseudoappendicitis* Yersi>Campy>Salm (like Shig!)

44

Campylobacter jejuni

G- ox positive curved motile rod

45

Campy found in

chickens, other birds, dogs, livestock, etc

46

Campy infection causes


temp specificities?

diarrhea, dysentery or both
also assoc. with jejunal lesions and extra intestinal infections (bacteremia-it's invasive!)
grows well at 42 deg. C under reduced O2 tension (microaerophilic) w. selective abx

47

?? used to be the leading cause of bacterial diarrheal disease ww, passed up by Salmonella

Campy
2 mil/yr in US

48

Campy reservoir

low or high infectious dose??

transmitted how?

risks

GIT of birds, *domestic fowl*, swine, cattle, sheep, dogs, etc

low infectious dose (800)

NOT usually person-person but via transmission from food sources, contaminated water
*raw mild and undercooked chicken* OR fecal contaminated foods

49

Campy age/gender/season assoc.

no age/gender
peaks in summer

50

Campy injures both the ???
lesions show an ??
isolates produce ??
-->resulting in ??

sm and large intestine
acute exudative and hemorrhagic inflammation
an enterotoxin and/or a cytotoxin (Stx)
diarrhea and/or dysentery

51

Campy virulence factors

enterotoxin: heat-labile (like LT of ETEC or CT of cholera)-seen in some strains from ppl w. acute secretory diarrhea

cytotoxin: Stx-->ulceration of mucosa

invasion factor

cytolethal distending toxin (CDT)

52

Campy invasion factor:??? proteins which are secreted through ?? upon contact with eukaryotic cell

Cia (Campy invasion Ags) secreted thru flagella filament


53

Campy invasion factor mechanism

disrupts epi cell tight junctions
allows cells to replicated IC in macros and induce apoptosis
triggers activation of NF-kB and MAPK signaling pathways

54

Campy Cytolethal distending toxin


mechanism?

(CDT): tripartite AB toxin where dtA and CdtC comprise the binding components and CdtB is the active subunit

CdtB is transported to the nucleus-->induces double stranded breaks in DNA and arrests the cell in G2 phase
-may play a role in malignancy

55

Campy immunity

Ab mediated

56

Campy disease often has a ??

prodrome:
fever (12-24 hrs before diarrhea) ha, myalgia, malaise

57

Campy onset??
most common presentation??

1-7 days
enteritis with diarrhea: loose, may be watery, may have dysentery
malaise, fever, abdominal pain (cramping)

58

is Campy self-limiting?

yes, improvement in several days

59

may also see ?? in Campy
which persists for ??

acute colitis: fever, tenesmus, sev. dysentery, sev. abd. cramps
1 wk

60

may also see ?? which can get bad enough to mimic ??


caused by ??

mesenteric LAD-->severe acute LRQ pain, can mimic appendicitis
Yersi>Campy>Salmy
caused by org getting to LN and causing sev. inflammation

61

Campy can also have extra intestinal manifests:

bacteremia
reactive arthritis in HLA-B27 peeps

62

Autoimmune manifests of Campy


what else can cause it?

Guillain-Barre: acute polyradiculoneuritis; AI attack on peripheral nerve myelin
Campy chief instigator-->sev. axonal form
also CMV, EBV, HIV and vaccinia virus
Pen 19, O:19, Lior 11, Lau 19 and 3/25

63

how Campy causes Guillain-Barre

LPS antigenic ally resembles human gangliosides Gm1 and GD1a
anti-Gm1 Abs-->cause symptoms

64

Campy jejuni assoc. with this malignancy

immunoproliferative small intestine disease (IPSID), a form of MALT lymphoma

responds to abx

65

recurrent acute Campy triggers

IBD

66

may carry/excrete Campy after recovery for ??
life-long??

2-3 wks
life-long in animals,

67

dx Campy: unique pres. features and labs

*prodrome and fever*
motile curved rods in feces and sea-gull shapes
+fecal leuks and RBCs
*Cx feces at 42d C under microaerophilic conditions*

68

Campy ddx

all febrile diarrhea/dysentery orgs

69

Campy tx

Erythromycin or other macrolide abx
and aminoglycosides
*both are protein-synthesis inhibitors*

70

Yersinia enterocolitica

G- non-coliform (white on MacConkey), motile, bipolar staining (safety pin) coccobacillus
>50 serotypes, 5 biotypes

71

Yersi is ?? so can multiply in ??

facultative IC, can multiply in epi cells and macros

72

Yersi causes ??

important cause of ??

diarrhea, mesenteric LAD, systemic disease with local abscesses
pseudoappendicitis

73

Yersi temp range

optimal: 22-29 C, can grow from 0-42

74

Yersi found in ...

GIT of wild and domestic animals
agent of sporadic outbreaks

75

Yersi: low or high infectious dose ??
transmitted how??

high: 10^9
BUT person-person still happens
most common vehicles: milk, milk products, canned meat, meat products, blood transfusions

76

Yersi age/gender/season

kiddos
no gender pref.
WINTER! (think Swedes?)

77

Yersi virulence: orgs invade via the ???

and establish residence in ??

may extend to ??

M cells of Peyer's patch

reticuloendothelial tissue, in LP, and muscular is mucosa

mesenteric LNs-->flamed and ulcerated nodes

78

complication of Yersi invasion

bacteremia, intestinal perf and peritonitis

79

Yersi virulence expression controlled by 2 feedback loops

temp and Ca2+

80

Step 1. Yersi org enters body in food/drink only produces ?? and ??

invasin: adhesion which binds to B1 integrin and induces endocytosis
ST-like enterotoxin (ETEC-guanylate cyclase)

81

Step 2. at 37d C synthesis of ??? stops and
synthesis of ?? begins

invasion and ST-like toxin
proteins which mediate resistance to complement-mediated killing

82

Step 2.2. ?? are also synthesized but only when low levels of ??

mechanism ??

other activity ??

YOPS: yersi outer membrane proteins
low levels of Ca2+

YOPS inhib. phago, INF-y activity, and macro. respiratory burst

have tyrosine phosphatase activity, mediate contact-dependent cytotoxic activity that depolymerizes actin microfilament network of target cell

83

Yersi onset?
presentation ??

4-7 days
fever, abd pain, vomiting, diarrhea

84

sev. Yersi presentations (age groups?)

fever, acute ileitis, leukocytosis (older children, adolescents)

enterocolitis (kiddos

85

Yersi post-inf. complications

reactive arthritis in HLA-B27's, erythema nodosum
extraintestinal infections: high serum iron-->poor px

86

Yersi carriage/shedding for how long ??

weeks

87

Yersi Cx

requires special medium and cold enrichment

88

Yersi ddx

febrile diarrhea/dysentery agents

89

Yersi tx

maintain fluid/e-lyte balance
aminoglycosides, TMP-SMX

90

Salmonella serotypes highly adapted to humans

S. typhi (prototype-typhoid fever)
S. paratyphi
S. sendai
-no known reservoir outside humans

91

Salmonella highly adapted to specific non-human hosts

S. cholerasuis (pigs)
-can cause inf. in humans but uncommon

92

Salmo w. broad host range

most in this category, cause most human and nonhuman disease: S. enteritidis, S. typhimurium- "Enteritidis" Group

93

Salmonella is a ??

G- rod,
non-lactose fermenting (non-coliform- white on MacConkey)
facultative anaerobe, non-fastidious, non-spore forming

94

Salmonella is a ?? which can multiply in ??

facultative IC pathogen, multiply in macros and intestinal epi cells

95

is Salmo motile or non-motile?

motile, has H Ag (flagella)
>2000 serotypes based on O and H Ags

96

Salmonella peaks in what age groups

6 mos to 5 yrs

97

Salmo reservoir??


high or low infectious dose??

transmitted how??

*fowl (eggs)*, swine, cattle, dogs, sheep, cats, turtles, rodents (NOT S. typhi)

high infectious dose: 10^5-10^9 orgs

typically ingestion of food/water
human-human has happened: closed pops, daycare, oral-anal

98

Salmonella may be carried for how long??
infants may shed for how long ??

5 wks
5-12 mos

99

Salmonella seasonality

summer/fall

100

Salmonella risk factors


why in industrialized countries?


other risk factors ?? may present w/ ??

use of PPIs
institutionalization

industrialized countries: bulk food processing, feed additives, food packaging/preservation, *infection of chicken oviducts*

Ca, AIDs, raw milk, DM, abx therapy-->may present with bacteremia

101

diarrhea induced in Salmonella as org ??


what virulence factor involved ??

travels thru small and large intestine via activation of adenyl cyclase-->inc. cAMP

enterotoxin, like LT toxin

102

Salmonella colonizes the ??? and invades the ?? (via inducing phagocytosis); invades both ?? and ??

virulence factor involved?? mechanism ?

ileum and cecum, mucosa
M cells and epi cells

Surface adhesion proteins: Type III secret. system (TTSSs) injects effector proteins into host cells

3 pathogenicity islands? result in cell apoptosis, necrosis, and excretion of IL-8

103

Salmonella causes ?? via what virulence factor ??

induces ??

acute inflammation via IC multiplication/prod. of Stx

release of inflamm. cytokines that cause intestinal damage (in addition to cytotoxin)-->see RBC and PMNs/macros in feces
cytokines also elicit systemic symptoms of fever, chills, and. pain

(this inflammation also contribute to diarrhea/dysentery)

104

orgs that have Stx (Shiga toxin)

Shigella dysenteriae (no shit)
EHEC, STEC, EIEC, EAEC
Campy
Salmonella

105

Salmonella causes systemic disease via this virulence factor ??
how does it spread ??


can cause??

LPS

spreads to mesenteric LNs-->then circulation-->bacteremia/endotoxic shock-->into macros (facult. IC)

causes pseudoappendicitis

106

what is required for Salmonella immunity/control??

CMI

107

Salmonella onset??
presentation??
duration ??
may affect who more severely?

12-48 hr incubation, abrupt onset
fever, chills abd. cramps, diarrhea, ha, vomiting
2-3 days normally
infants, oldies, impaired CMI

108

Salmonella complications

reactive arthritis in HLA-B27s, bacteremia,
pseudoappendicitis

109

reactive arthritis (HLA-B27s) is a complication in these infections

STEC, etc
Shigella
Campy
Yersi
Salmonella

110

Salmonella dx microscopic

fecal leuks and macrophages more than PMNs
FAT (fluorescent Ab test)

111

Salmonella dx Cx

do: feces, water, food, blood (if fever)
enhancement, selective and ddx media
serological confirmation and typing *reportable*

112

Salmonella dx

agents of febrile diarrhea/dysentery

113

Salmonella tx

maintain fluid/e-lyte balance
abx NOT recommended for uncomp. gastroenteritis

114

how to prev. salmonella

cook foods containing eggs all the way

115

febrile invasive food-borne agents

Vibrio parahaemolyticus, V. vulnificus
Balantidiasis coli

116

Vibrio parahaem. and V. vulnificus

ox +, halophilic curved rods (sim to V. cholera)

117

V. para normally inhabits ??

US outbreaks relate to ???

high or low dose ??

season ??

2 major outbreaks occurred where ??

marine waters- animals

eating seafood *shrimp*

high infectious dose 10^5-10^7

summer mos

on cruise ships

118

V. para can be ?? and cause ??

via what virulence factor ??

invasive and cause systemic disease

LT-like toxin

119

V. para onset ??
presentation ??


what typ. observed ??

>14 hrs
diarrhea and/or dysentery, cramps, N/V and 1/3rd are bacteremic

leukocytosis

120

V. para dx: microscopy

direc microscopic examination of diarrheic stool:
*curved rods, feca. leuks, RBCs*

121

V. para dx: Cx

isolate feces/vomit org on high NaCl media

virulent strains are Kanagawa positive and produce beta hemolysis on human blood agar

122

V. para dx

any febrile diarrhea/dysentery agent assoc. with contact with marine environ.

123

V. para tx

rehydration
amipicillin and other abx for sev. diarrhea/fever

124

how to prev. V. para

don't eat raw seafood, don't contaminate cooked seafood

125

V. vulnificus

like V. para in appearance and habitat
*is highly invasive*

126

3 syndromes caused by V. vulnificus


leading cause of ??

wound infections (45%)
primary septicemia (43%)
gastroenteritis (5%)
*leading cause of seafood assoc. fatalities in US*


127

V. vulnificus sev. progession

necrotic, rapidly progressing lesions-->fulminant sepsis w. 75-90% mortality in at risk individuals (25% normal hosts w. tx)



128

those at risk for sev. V. vuln disease

DMs, etOHs, liver dysfunctions, hemochromatosis (Fe-overload)
*don't eat raw seafood!*

129

Balantidium coli

ciliated protozoan
*largest to infect humans*
causes diarrhea/dysentery

130

Balantidium coli reservoir

pigs!

131

B. coli is ingested as ?? and migrates to ?? where it develops into ?? which do what ??

cysts, migrate to large intestine, cecum, terminal ileum
trophozoites which replicate via binary fission and conjugation while consuming bacteria

132

B. coli trophozoites reside primarily within the ?? but may ???

intestinal lumen
may penetrate the mucosa and cause ulcers

133

B. coli presentation in immunocompetents
otherwise presentation

typ. asymptomatic
bloody, mucoid diarrhea, N/V, abd. pain, anorexia, wl, fever, colitis, dehydration

134

B. coli dx

wet Sm of stool specimen; see trophozoites: LARGE, ciliary covering, spiraling motility

135

Balantidium coli tx

volume/e-lyte replacement
tetracyclin or metronidazole

Decks in Micro Class (61):