Chapter 9: The Enterics

Front 1

What are the main groups of enteric bugs?

Back 1

Enterobacteriaceae, Vibrionaceae, Pseudomonadaceae, and Bacteroidaceae

Front 2

Which enterics DON'T ferment lactose?

Back 2

Salmonella, Shigella, and Pseudomonas

Front 3

Describe three levels of intestinal invasion causing diarrhea?

Back 3

1. no cell invasion, diarrhea is caused by exotoxin-mediated fluid loss.
2. Invasion of the intestinal epithelial cells - systemic immune response with WBC infiltration and RBC leakage into the stool.
3. Invasion of the lymph nodes and bloodstream - diarrhea and systemic symptoms

Front 4

What are the diseases caused by E. coli?

Back 4

1. Diarrhea
2. UTI
3. Neonatal meningitis
4. Gram (-) sepsis, commonly in debilitated patients

Front 5

What are the three groups of diarrhea-producing E.coli?

Back 5

1. Enterotoxigenic E.coli (ETEC)
2. Enterohemorrhagic E.coli (EHEC), including E.coli 0157:H7 which causes HUS
3. Enteroinvasive E.coli (EIEC)

Front 6

Describe the diarrhea caused by ETEC?

Back 6

Heat stabile and heat labile toxins are like cholera exotoxins - severe watery diarrhea, stool looks like rice water

Front 7

Describe the diarrhea caused by EHEC?

Back 7

Shiga-like toxin causes bloody diarrhea

Front 8

Describe the diarrhea caused by EIEC?

Back 8

Bloody with WBCs, like shigellosis. Also causes fever.

Front 9

How can E.coli travel up the urethra?

Back 9

Acquisition of a pili virulence factor.

Front 10

What are the three leading causes of neonatal meningitis?

Back 10

Group B strep, E.coli, and Listeria.

Front 11

What is the most common cause of gram (-) sepsis?

Back 11

E.coli

Front 12

What is Klebsiella pneumonia?

Back 12

Encapsulated, nonmotile bug, causing sepsis, UTI, and pneumonia, characterized by a red currant jelly sputum.

Front 13

Why is Proteus useful for lab tests?

Back 13

Cross-reacting antigens with some Rickettsia serves as a clinical tool for determining whether someone has been infected with Rickettsia.

Front 14

Describe characteristic of Shigella. Contrast with E.coli.

Back 14

Nonmotile, does not ferment lactose and does not produce H2S. Humans are the only host - and Shigella is always a pathogen.

Front 15

What illness does Shigella cause?

Back 15

Begins with fever, abdominal pain, and diarrhea, which may contain blood and pus.

Front 16

Describe characteristics of Salmonella?

Back 16

Non-lactose fermenter, is motile, and produces H2S.

Front 17

What are the three clinically significant groups of Salmonella?

Back 17

S. typhi, S. cholerae-suis, and S. enteritidis

Front 18

Salmonella causes which 4 disease states in humans?

Back 18

Typhoid fever, carrier state, sepsis, and gastroenteritis

Front 19

Describe clinical features of typhoid fever?

Back 19

Fever, headache, and abd. pain that is often localized to the right lower quadrant. Diarrhea may develop, spleen may enlarge, and rose spots may appear on the abdomen.

Front 20

What is appropriate therapy for Salmonella typhi?

Back 20

Ciprofloxacin or ceftriaxone

Front 21

Salmonella sepsis is usually caused by which bug? Which organs does it primarily infect?

Back 21

Salmonella choleraesuis. Infects lungs, brain, or bone.

Front 22

Why are sickle-cell patients particularly prone to Salmonella osteomyelitis and other infections?

Back 22

Their asplenic state makes it difficult to clear these encapsulated bacteria. (Normally, macrophages and neutrophils in the spleen phagocytose opsonized bacteria)

Front 23

Salmonella diarrhea is usually caused by…? Treatment?

Back 23

Salmonella enteritidis. Treatment involves fluid and electrolyte replacement.

Front 24

What is Yersinia enterocolitica? Causes pain where?

Back 24

Motile gram-negative rod, transferred by the fecal-oral route. Pain in the right lower quadrant of the abdomen.

Front 25

What is Yersinia enterocolitica’s unique survival feature?

Back 25

Can survive and grow in the cold.

Front 26

Vibrio cholera shape?

Back 26

Curved gram-negative rod with a single polar flagellum.

Front 27

V. cholera causes a similar (though more severe) disease as which E.coli subtype? Produces what kind of diarrhea?

Back 27

ETEC. Watery (rice water) diarrhea.

Front 28

What are the three most common causes of diarrhea in the world?

Back 28

Campylobacter jejuni, ETEC, and the Rotavirus.

Front 29

Campylobacter jejuni causes which type of diarrhea?

Back 29

Bloody, loose diarrhea.

Front 30

What is the most common cause of duodenal ulcers? Gastric ulcers?

Back 30

Helicobacter pylori. Aspirin products.

Front 31

Describe Pseudomonas aeruginosa? Shape, gram, scent, invasive ability, toxins?

Back 31

Obligate aerobic gram (-) rod. Produces grape-like scent. Weak invasive ability. Exotoxin A, similar mechanism as diphtheria toxin.

Front 32

List the important Pseudomonas infections?

Back 32

1. Pneumonia
2. Osteomyelitis
3. Burn-wound infections
4. Sepsis
5. UTIs, pyelonephritis
6. Endocarditis
7. Malignant external otitis
8. Corneal infections

Front 33

Which patients are at-risk for Pseudomonas pneumonia?

Back 33

CF patients and immunocompromised patients.

Front 34

Which patients are at risk for Pseudomonas osteomyelitis?

Back 34

Diabetics, IV drug abusers, children with puncture wounds to the foot.

Front 35

What is the general treatment regimen for Pseudomonas?

Back 35

Anti-pseudomonal penicillin combined with an aminoglycoside for synergy

Front 36

When do we encounter Bacteroides fragilis infections?

Back 36

Bullet wounds through the intestine, seat belt lacerations in MVA’s, bowel penetration in abdominal surgery, etc.

Front 37

Following abdominal surgery, which antibiotics that cover anaerobes are given as prophylaxis?

Back 37

Clindamycin, metronidazole, chloramphenicol, etc.