Enteric Gram-Negatives Flashcards
(139 cards)
1
Q
UTI and urosepsis in elderly nursing home resident
A
UPEC (E. coli leading cause of UTI)
2
Q
Enteric infection with hemorrhagic colitis in child
A
EHEC O157:H7 (E. coli 4th leading cause of enteric infection in US)
3
Q
Neonatal sepsis & meningitis
A
NMEC, K1 E. coli (#2 cause)
4
Q
Normal commensal bowel microbiota
A
All E. coli
5
Q
Laboratory workhorse
A
K12 E. coli
6
Q
G- Membrane
A
Inner membrane
Thin peptidoglycan membrane (periplasm w/LPS)
7
Q
O-antigen
A
Oligosacc side-chains (endotoxin)
8
Q
Traveller’s diarrhea
A
ETEC
9
Q
childhood diarrhea in underdeveloped places
A
EPEC
10
Q
2 ways of getting a UTI
A
Descending via hematogenous spread
Ascending via periurethral region (colon microbiota)
Ascending aka retrograde most common: Gut - urethra - bladder (bacteriuria) - ureter - kidney (pyelonephritis)
11
Q
Leading cause of UTI
A
E. coli
Type 1 fimbrae
PAP
Siderophores
12
Q
Produces urease
A
Proteus
Can lead to stone production and obstruction
13
Q
Diarrhea
A
Frequent stools
Painless, no fever
Infectious and non
Increased secretion/decreased absorption in SI or LI
14
Q
Dysentery
A
Pus and blood in stool
Painful (cramps, tenesmus)
Fever
Invasion or cytotoxin destruction of LI
15
Q
Enteric fever
A
systemic infection starting in GI tract
e.g. typhoid
16
Q
Gastroenteritis characterisitcs
A
Catch-all for syndromes
NVD
Toxins or superficial inflammation
Infectious and non-
17
Q
High acid tolerance organism (2)
A
Shigella
EHEC
18
Q
Top 4 bacterial causes of enteric infections
A
Campylobacter (1/2)
Salmonella
Shigella
E. coli
19
Q
Traveller’s diarrhea
Similar to vibrio cholera (toxin)
A
ETEC
20
Q
Infantile diarrhea
Similar: non-typhoid Salmonella
A
EPEC
21
Q
Hemorrhagic colitis, HUS
O157:H7
Cow intestines
Similar: Shigella (Verotoxin “shiga-like”)
A
EHEC
22
Q
O, H, K antigens
A
O: part of LPS in the outer membrane
H: flagella (motility)
K: capsule
23
Q
Sepsis bugs (PEEK)
A
Proteus
Escherichia
Enterobacter
Klebsiella
24
Q
Pneumonia bugs (SEEK)
A
Serratia
Enterobacter
Escherichia
Klebsiella
25
Meningitidis bug
Escherichia
26
UTI bugs (PEP)
Proteus
Escherichia
Providencia
27
Gastroenteritis bugs (YESS)
Yersinia
Escherichia
Salmonella
Shigella
Campylobacter
28
Intraabdominal infection
Escherichia
29
Enterobacter physiology (3)
Facultative anaerobes
Ferment glucose
Oxidase-negative
30
Tracheobronchitis bug
Bordetella pertussis
31
URI/OM/meningitis/sepsis bug
Haemophilus
32
Gastritis/ulcers/gastric cancer bug
Helicobacter
33
URI/OM bug
Moraxella
34
Genital infection/STI
| Nasopharyngeal colonization/meningitis/sepsis
Neisseria gonorrhea
| Neisseria meningitidis
35
Lung/skin/eye/burn/wound/blood
Pseudomonas
36
Gastroenteritis/skin lesion bug
Vibrio
37
4 leading bacterial enteric pathogens in the US
Campy
Salmon
Shiggy
Escher
38
Type 1 pili attach to what?
Mannose molecules
39
P pili or "PAP" attach to what?
| Host receptor? P1 blood phenotype assoc w/?
P for "pyelonephritis" attach to gal-gal
P blood group antigen on renal pelvis cells
P1 phenotype have predisp to recurrent upper-UTI
40
MR of uropathogenic ecoli?
Biofilms
41
Capsules do 3, capsular agents e.g. (NESH)
```
Size, charge, concealment
Neisseria
Ecoli
Strep pneumo
H. flu type b
```
42
Siderophores
secreted iron-chelating compounds that compete w/host iron-binding compounds
43
How does Neisseriae scavenge iron?
surface proteins bind host iron-containing transferrin and lactoferrin
44
4 cytotoxins to know
```
Shiga toxin (shigella)
Verotoxin (EHEC)
Vacuolating toxin (H. pylori)
Exotoxin A (pseudomonas)
```
45
Hydrolytic enzyme bugs (2)
Pseudomonas (lots)
| NeisseriAe, hAemophilus --> IgA protease
46
Acid tolerance:
Shigella, EHEC
Vibrio
Salmonella
```
Highly resistant (1-100)
Highly sensitive (+10^8)
Intermediate (10^6)
```
47
UTI RF's
catheter
abx
immunocomp
environment --> selective pressure
48
Most common source of bacteremia in the elderly?
urinary tract
49
How does E coli get in?
Principally via mouth
50
Important molecule for ascending UTI?
Adhesins --> stick to uroepithelium
| Targets for vaccines
51
providencia
Nosocomial UTI in catheterized pts
| From animals/environment
52
normal intestinal microbiota
urease producer --> alkalization of urine
--> salt precipitation --> struvite stones
adhesive pili
proteus mirabilis
53
K1 encapsulated NMEC
2nd in bacterial neonatal meningitis (GBS #1)
| No opsonization --> sialic acid abundant in mammals, poorly immunogenic (mom doesn't make antiB's)
54
Do GNR's cause CAP in healthy individuals?
No. Elderly, alcoholics, IV drug users, lung disease
| Nosocomial pneumonial common in hospitalized pts
55
4 Klebsiella spp that cause pneumonia (poor)
Pneumoniae
Oxytoca
Ozaenae
Rhinoscleromatis
56
Klebsiella characteristics
```
Facultative anaerobe
Nonmotile
Ferments lactose
Capsule
VISCOUS MUCOID COLONY ON SOLID MEDIUM
```
57
Lobar pneumonia
Severe --> hemorrhagic necrotizing consolidation
"CURRANT JELLY" sputum
Abscess common
Pneumonia caused by Kleb
58
Serratia
Nosocomial pneumonia
| S. marcescens --> INTENSE RED PIGMENT in culture
59
Pigmented or non pigmented serrata cause pneumonia, bacteremia, endocarditis in IV druggies and hosp pts?
Nonpigmented
60
Serratia, E. coli, Enterobacter, Kleb share what features of pneumonia pathogenesis?
Opportunism (CA in immunocomp hosts: debilitated, elderly, alcoholics, IV) also nosocomial
Presentation (severe necrotic pneumonia w/purulent sputum, hemorrhagic, abcess)
61
Factors influencing GI ecology
pH, osmolarity
age/diet
motility
host-microbe/microbe-microbe
62
3 bugs of cholecystitis (complication of obstruction due to stones) Bile Can't Empty
Bacteroides fragilis
Clostridium
Escherichia
LI --> SI --> ascend biliary tree
63
Which bug's resistance to bile salts allows it to colonize the gallbladder?
Salmonella
64
Microbes that adhere and resist the cleansing effects of the upper SI (enterotoxin producers "Very Extreme Pathogens")
Escherichia
Vibrio
c. Perfringens
65
Terminal Ileitis bug?
Yersinia entercolitica
66
First LI colonizers in the newborn?
E. coli, streptococci
| Consume oxygen and encourage anaerobes
67
Breast-fed infants are colonized with what?
Bifidobacterium (anaerobic G+ rods)
68
Which G- obligate anaerobe ultimately dominates in the colon?
Bacteroides
69
Intoxication (pre-formed): site, clinical, examples
small bowel
severe NVD
S. aureus, B. cereus
70
Secretory toxin: S.C.E.
small bowel
profuse watery diarrhea
no/mild pain and fever
ETEC, Vibrio
71
Cytotoxin: S.C.E.
large bowel
bloody diarrhea
painful cramps, +/- fever
EHEC 0157:H7, Shigella
72
Mucosal colonization/destruction: S.C.E.
Small bowel
NVD, vomiting
EPEC, Salmonella, Campy
73
Deep invasion: S.C.E.
Large bowel
Purulent bloody dysentery
Painful cramps, fever
EIEC, Shigella, Campy
74
Systemic dissemination: S.C.E
GI --> blood --> liver --> GI
systemic sx
Salmonella typhi
75
3 obligate human pathogens (primates)
| Fecal/oral transmission
Salmonella typhi
Shigella
Helicobacter pylori
76
3 zoonotic pathogens (animal reservoir)
E. coli (ground beef)
Non-typhoid Salmonella (poultry, eggs, reptiles)
Campylobacter (poultry, milk, puppies)
*once infected humans can transmit via feces
77
E. coli
fecal/oral
ground beef, spinach irrigated w/wrong water
ETEC/EPEC --> humans
EHEC --> cows
78
ETEC
Traveler's diarrhea
ST/LT SECRETORY toxins (cholera-like; plasmid-mediated)
--> Hyper secretion of fluid
Watery diarrhea for 3-4 DAYS
79
Watery diarrhea for 3-4 days
ETEC
80
EPEC
infantile diarrhea
gastroenteritis --> invasion/destruction of SI epithelium
fever, NVD (non-bloody)
81
zoonotic cow intestine or via infected humans
| children during warm months
```
EHEC (O157:H7)
small inoculum
verotoxin (shiva-like)
hemorrhagic colitis w/severe abd pain, HUS
BLOODY diarrhea
```
82
Complication of EHEC
HUS --> systemic disease via escape of the cytotoxin from the intestine into the blood
83
Thrombotic microangiopathy
Hemolytic anemia
Thrombocytopenia
Renal lesions
=HUS
inflammatory/thrombotic effects
damage via inhibition of protein synthesis/induction of apoptosis
84
HUS risk groups
children/elderly
85
treatment for EHEC?
NO ANTIBIOTICS
86
EIEC
invade LI mucosa
| BLOODY/PURULENT dysentery
87
eggs (inside and out), poultry, pets, amphibians, reptiles, chicks, ducks
children in warm months
Salmonella enterica
fecal/oral
LARGE INOCULUM
88
"rotten egg" stools
Salmonella syndrome: Simple gastroenteritis (non-typhoid)
sulfhydryl compounds
organisms are resistant to bile salts
89
phagocytosis, replication, transport in macrophages
salmonella systemic illness
reinvasion of SI via bile
blood culture + 1st week, stool + 2/3rd week
90
Sequelae of salmonella systemic illness (3)
```
Enteric fever (typhoid w/systemic sx)
Metastatic foci: splenic abcess, osteomyelitis (sickle cell), endovascular (septic atherosclerotic plaques)
Carrier state (gallbladder: Typhoid Mary: asymptomatic: may shed bacteria)
```
91
Vaccines effective for non-typhoid salmonella?
No
92
Shigella
```
fecal/oral
daycare
ascending/descending route via ANAL SEX
no animal reservoir
SMALL INOCULUM
```
93
Where does shigella invade?
| Where does it not invade?
```
LI (invasion/destruction), DOES NOT invade blood
BACILLARY dysentery (~EIEC) >> gastroenteritis
fever, HEADACHE, SEIZURES
```
94
Campylobacter jejuni
poultry, unpasteurized milk, contaminated water
fecal/oral
pets, domestic animals, rodents, fowl
95
```
Early gastroenteritis (~EPEC) --> late dysentery (~EIEC) --> rare enteric fever
How to dx this bug?
```
Campy
| Stool culture: DARTING motility w/polar flagella
96
Yersinia
fecal/oral
pets, rodents, farm animals
COLD months/countries
not major in US
97
Terminal ileitis --> mesenteric lymphadenitis --> abd pain --> "pseudoappendicitis"
Yersinia
also gastroenteritis, diarrhea
RARE bacteremia
98
Y. pestis
DOES NOT CAUSE ENTERIC infection
| humans-rodents via FLEAS, droplets
99
Big disease of Y. pestis
BUBONIC PLAGUE:
systemic infection in lymphatic sys
painful/swollen nodes "buboes"
100
Y. pestis infection spreading to lungs/blood
Pneumonic plague
| Septicemic plague
101
Vibrio cholerae
fecal/oral
Large inoculum (malnutrition increases risk)
Gulf coast during hurricans/floods
deadly for malnourished, children, debilitated
102
Voluminous watery "rice water" diarrhea (~ETEC)
V. cholerae
good for bacterial spread
shock --> death of host
HYDRATION
103
Antibiotics for cholera?
NO! Supportive care and electrolyte replacement
104
What is the pathogenesis of V. cholerae?
No INVASION
| gastroenteritis via mucosal colonization and secretory (A/B) toxin release
105
Vibrio parahemolyticus
Salt water, shellfish/sushi
Gastroenteritis, rare enteric fever
NE/NW US
106
Vibrio vulnificus
what makes this different from other 2 vibrios?
Risk groups? What's the characteristic lesion?
Salt water - shellfish, skin abrasions
Risk: immunocomp, alcoholics
Bullous wound infection --> septicemia
NO GASTROENTERITIS (unlike other 2 vibrios)
107
Helicobacter pylori
```
Fecal/oral
May be asymptomatic stomach colonization
Gastritis
Gastric and duodenal ulcers (PREDOMINANT)
Gastric malignancies
```
108
H. pylori colonization mechanism
urease --> microenv pH
USED FOR DX
inc prevalence with age, but high in childhood
109
Treatment for H. pylori
Amox + clarithro
| PPI (only once syndrome is dx'd: may inhibit bacterial motility) diminishes inflammation, damage, and sx
110
Which bug has propensity for bloodstream invasion? (aka enteric fever) NYCS
```
S. typhi
Rarely: other salmonella
Campy
Yersinia
Non-cholera Vibrio
```
111
Syndrome 1-4 weeks post-GI infection
| May also follow urogenital infection
Reactive arthritis (aseptic inflammatory)
112
Antibiotics for reactive arthritis?
No
113
When to use antibiotics?
Usually not needed unless...
Severe/protracted sx
At risk: infants, elderly, immunocomp
Quinolones (CIPRO)
114
Obligate human bugs (SESH)
Salmonella typhi
Shigella
H. pylori
Entamoeba histolyca
115
Zoonotic pathogens
E. coli
Non-typhoid salmonella (poultry, eggs, reptiles)
Campy (poultry, milk)
116
Typhoid fever tx?
Antibiotics
Vaccine for high-risk travel or occupations
Capsular polysacch
No vaccine for non-typhoid enteric fever
117
Enteric fever
Entry via GI tract (Peyer's patches)
Fever and abd pain predominant
Bloodstream --> liver (replicate in MP's here) --> gut via bile duct
118
Colonization of gall bladder can lead to?
Asymptomatic shedding of bacteria
119
Special tests
EHEC verotoxin ELISA in stool or serum
Rotazyme - stool ELISA for rotavirus
Stool ELISA for Entamoeba
120
Meds for sx relief of NVD
Bismuth subsalicylate (antimicrobial?)
GI motility reducing: loperamide, diphenoxylate
Do NOT use stasis drugs if BLOOD OR PUS IN STOOL
Consider probiotics for abx-assoc-diarrhea
121
Other vaccines of note
S. typhi
Rotavirus
Hepatitis A
122
daycare
shigella
123
4 sx of invasive shigella infection?
| resembles?
```
Fever
headache
seizures
dysentery
EIEC
```
124
rodents, fowl
campy
125
pets, rodents, farm animals in COLD places/times
Yersinia
126
how do you get a descending UTI?
hematogenous spread
127
how does e. coli get iron?
siderophores
128
intense red pigment on culture
Serratia marcescens
129
spread humans-rodents via fleas
Y. pestis
130
COD in cholera pts
septic shock
131
A/B secretory toxin
V. cholerae (does not invade)
132
Saltwater, shellfish/sushi
| NE/NW US
V. parahemolyticus
133
H. pylori infection dx by presence of what?
urease levels
134
do not use stasis drugs when?
if blood or pus in stool
135
anal sex
shigella
136
reheated fried rice
B. cereus
137
reheated meats/gravy
C. perfringens
138
UTI bugs that infect via descending hematogenous spread
S. aureus
| Candida
139
asymptomatic bacteriuria is seen in 100% of these patients
long-term indwelling catheters
