Microbiology Lecture X

Front 1

Enteropathogenic Bacteria general/ groups

Back 1

gram negative rods, 4 major groups: enterobacteriaceae, vibrionaceae, campylobacteriaceae, helicobacteriaceae

Front 2

Enterobacteriaceae (pathogens)

Back 2

escherichia coli, shigella, salmonella, yersinia pestis, enterocolitica

Front 3

Enterobacteriaceae (opportunitists)

Back 3

klebsiella, serratia, proteus

Front 4

General characteristics of Enterobacteriaceae

Back 4

gram negative, motile, peritrichious flagella, simple media growth, facultative anaerobes, characteristic fermentation patters,

Front 5

Enterobacteriaceae (virulence factors)

Back 5

endotoxin (o antigen), exotoxin (enterotoxins), adhesion factors (fimbriae (pili) & capsular proteins), capsules, flagella (H antigens)

Front 6

Coliforms

Back 6

E. coli, klebsiella, citrobacter, enterobacter; used as indices for fecal contamination of drinking water, regulatory standard < 5000 CFU/ml of water

Front 7

E. Coli

Back 7

faculative anerobe, lactose fermenter, produces indole from tryptophan; grow on MacConkey

Front 8

MacConkey agar

Back 8

contains neutral red dye which stains colonies when pH reaches below 6.8; grow E. coli on

Front 9

Indole test

Back 9

used on E. Coli, produces indole from trytophan

Front 10

*E. Coli (virulence factors)

Back 10

adhesion factors, enterotoxins *(heat-labile - similar to cholera toxin*; and a heat stable one); *Shigatoxin (verotoxin) - also produced by shigella dysenteriae type 1; hemolysins, anti-phagocytotic capsule (K1 sialic acid capsule)

Front 11

E. Coli urinary tract infectino

Back 11

most common cause of uncomplicated urinary tract infectino in women; frequency, dysuria, nocturia, hematuria, cystitis; flank pain, fever - pyelonnephritis

Front 12

Cystitis

Back 12

bladder infection; caused by e. coli - strains involved in cystitis have specific O antigens that act as adhesion factors

Front 13

Pyelonephritis

Back 13

nephron infection - strains causing pyelonephritis have unique P fimbrial antigens

Front 14

E. coli Urinary tract infection Diagnosis

Back 14

> 100,000 CFU/ml of urine; PMN high

Front 15

E. Coli Urinary Tract infection treatment

Back 15

Septra (trimethoprimsulfamethoxazole*) - susceptibility test if complicated

Front 16

*E. Coli GI infection (enterohemorrhagic E. Coli)

Back 16

EHEC; shigatoxin (stx), coded by lysogenic phage; food-borne: undercooked beef & spinach; hemorrhagic colitis, hemolytic iremic syndrome; very dangerous one

Front 17

*GI infection (Enterotoxigenic E. Coli)

Back 17

ETEC; LT,ST, Colonization factor; travelers and infants diahrrhea; watery diarrhea; non-invasive; very common one

Front 18

GI infection (Enteropathic E. Coli)

Back 18

EPEC; eatery diarrhea in infants, children

Front 19

GI infection (Enteroinvasive E. Coli)

Back 19

EIEC; rare in US; identical to shigellosis but no toxin, highly invasive, inflammation, necrosis, ulceration; profuse diarrhea, high fever

Front 20

Hemorrhagic Colitis

Back 20

caused by E. Coli O157:H7 "license plate strain"; EHEC; incubation 3-4 days; actutre bloody diarrhea and abdominal cramps w/ little or no fever; lasts about a week; ~73000 cases/yr; transmission = oral: beef, contaminated water, unpasteruized milk and juice, lettuce, pinach, salami

Front 21

Hemorrhagic Colitis (therapy)

Back 21

rehydration; use antibiotics if is extraintestinal

Front 22

Hemolytic Uremic Syndrome

Back 22

caused by license plate E. Coli; acute renal failure, thrombocytopenia, and hemolyctic anemia (own RBC are lysing); shiga toxin + LPS cause damage to glomerular endothelim; abdominal cramps, bloody diarrhea, nausea , vomiting; principal acute kidney failure in children in US; death - 5-10% of children

Front 23

Shigella sp.

Back 23

true human pathogen (no reservoir); is considered to be E. Coli; 4 species w. many serogroups (shigella sonnei (in US), S. Dysenteria (epidemic)); *do not fermemnt lactose; non-motile; invade gut via M cells

Front 24

Shigella sp. (virulence factors)

Back 24

Shiga toxins 1 and 2: phage gene; A (toxic) and B (sticky) subunits; binds to vascular endothelial cells (*gut, kidney lungs*, in SI blocks absorption of electrolytces, sugar, and AA- causes diahrrea); large virulence protein

Front 25

Shigella sp. A subunit

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is a virulence factor, halts protein synthesis, cell death; dysentery

Front 26

Shigella sp. Large virulence plasmid

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encodes factors invovled in adhesion, invasion, cell-cell spread

Front 27

Shigellosis

Back 27

Fecal oral transmission (conminated food/water; low infectious dose 102-104 CFU); incubation 1-3 days; major cause of bacillary dysentery; HUS may occur in small subset of patients

Front 28

Dysentery

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inflammation of intestines (especially colon), severe abdominal cramps, tenesmus, frequent low volume stools containing blood, mucus, and fecal PMNS

Front 29

Tenesmus

Back 29

straining to defecate

Front 30

Bacillary dysentery

Back 30

dysentery caused by bacterial infection with invasion of host cells.tissues and/or productions of exotoxins

Front 31

Shigellosis diagnosis

Back 31

culture feces, PMN in feces

Front 32

Shigellosis treatment

Back 32

supportive: fluid replacement; DOC*: amoxicillin or ampicillin' prevention: sanitation, personal hygeine

Front 33

Hemolytic Uremic Syndrome classification

Back 33

HUS; shigatoxin-associated, non-shigatoxin associated

Front 34

Shigatoxin -assocaited HUS

Back 34

E coli O157:H7 (most common) and Shigella dysenteriae type 1; primary epidemic form in > 90% of cases; usually in children 2-3; 75% diahrrea

Front 35

non-shiagtoxin associated HUS

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sporadic or familial; worse prognosis : mortality 50%; 40% associted with invasive S. pneumonia; other causes: viruses, drugs, cancer, pregnancy

Front 36

Early Stage Shigellosis

Back 36

watery diahrrea due to enterotoxic activity of Shiga toxin; fever

Front 37

Second stage Shigellosis

Back 37

adherence to and invasion of large intestine; due to cytotoxic activity of shiga toxin