BacT1

Question 1

What family does Escherichia coli belong to?

Answer 1

Enterobacteriaceae

Question 2

What type of organism is Escherichia coli?

Answer 2

Gram negative bacili, facultative anaerobe

Question 3

What is the primary transmission route for Enterotoxigenic E. coli (ETEC)?

Answer 3

Fecal-oral; ingesting contaminated water/food

Question 4

What are the major toxins produced by ETEC?

Answer 4

• STa (heat-stable toxin A)
• STb (heat-stable toxin B)
• LT (heat-labile toxin)

Question 5

What clinical signs are associated with ETEC infection?

Answer 5

Non-inflammatory diarrhea

Question 6

What are some prevention strategies for ETEC?

Answer 6

• Colostrum management
• Nutrition of cow
• Hygiene and calf management
• Cow vaccination

Question 7

What diagnostic tests are used for ETEC?

Answer 7

• PCR
• Agglutination tests for fimbriae
• Culture on MacConkey agar

Question 8

What is the primary treatment for ETEC infections?

Answer 8

• Aggressive fluid therapy
• Enteral and parenteral
• Plasma transfusion
• +/- Antibiotics

Question 9

True or False: E. coli is the most common cause of diarrhea in farm animals.

Answer 9

True

Question 10

What is Shigatoxigenic E. coli (STEC) also known as?

Answer 10

Enterohemorrhagic E. coli (EHEC)

Question 11

What is the primary transmission route for STEC?

Answer 11

Fecal-oral; ingesting contaminated water/food

Question 12

What are the clinical signs of STEC infection in humans?

Answer 12

• Hemorrhagic enteritis
• Hemolytic uremic syndrome
• Chronic renal insufficiency

Question 13

What is the role of the LEE in STEC?

Answer 13

Mediates attachment to host epithelial cells

Question 14

What is Enteropathogenic E. coli (EPEC) known for?

Answer 14

Attaching and Effacing E. coli

Question 15

What is a key characteristic of EPEC’s pathogenicity?

Answer 15

Colonizes mucous layer of intestines

Question 16

What type of infections does Extraintestinal Pathogenic E. coli (ExPEC) primarily cause?

Answer 16

• Urinary tract infections
• Mammary gland infections
• Colisepticemia

Question 17

What is the main reservoir for Yersinia enterocolitica?

Answer 17

Domestic animals and primates

Question 18

What are the clinical signs of Yersinia enterocolitica infection?

Answer 18

• Diarrhea (often bloody)
• Fever
• Abdominal pain

Question 19

What is the main transmission route for Salmonella enterica?

Answer 19

Fecal-oral; ingesting contaminated water/food

Question 20

What is a common clinical sign of Salmonella infection in cattle?

Answer 20

Acute enterocolitis

Question 21

What are the common serovars of Salmonella in chickens?

Answer 21

• S. Enteritidis
• S. Gallinarum
• S. Pullorum

Question 22

What is the role of the Type III secretion system (T3SS) in Salmonella?

Answer 22

Facilitates invasion of intestinal epithelial cells

Question 23

What are the main diagnostic methods for detecting Salmonella?

Answer 23

• Culture (feces, intestinal contents, blood)
• Real-time PCR
• Serology

Question 24

What is the significance of using a genetic target in rapid testing?

Answer 24

Conserved across all subspecies and provides results in less than 48 hours.

Sometimes more sensitive than culture, but subtyping and antimicrobial susceptibility testing are not possible.

Question 25

What is the primary use of serology in veterinary diagnostics?

Answer 25

Herd or flock-level testing for specific antigens, not generally used for individual animals. ## Footnote Example: control programs for milk bulk tank testing, such as for Dublin.

Question 26

What does ELISA indicate in serological tests?

Answer 26

Serology indicates an immune response to a pathogen in the past. ## Footnote It does not provide current infection status.

Question 27

What is the Kauffmann-White Serotyping Scheme?

Answer 27

Uses antibodies raised against specific O antigens and H antigens. ## Footnote O antigens are LPS components, while H antigens are flagellar proteins.

Question 28

What are some subtyping methods beyond serotyping?

Answer 28

Useful in outbreak investigations and includes: * MLST (sequence typing) * PFGE (pulse field gel electrophoresis) * SNP typing (single nucleotide polymorphism) ## Footnote FDA uses these methods for foodborne outbreaks.

Question 29

What types of samples are collected for Salmonella testing?

Answer 29

Antemortem: several grams of feces Postmortem: intestinal contents and other sites if animal is septic (lung, liver, kidney, spleen) Environmental: especially equine using Swiffers. ## Footnote These samples help in identifying the presence of Salmonella.

Question 30

What antibiotics are appropriate for treating severe cases of Salmonella?

Answer 30

3rd generation cephalosporins, fluoroquinolones, trimethoprim/sulfamethoxazole. ## Footnote Only appropriate in sepsis and immunocompromised patients.

Question 31

What is the recommendation regarding the use of antibiotics for diarrhea caused by Salmonella?

Answer 31

DO NOT TREAT DIARRHEA with antibiotics. ## Footnote Antibiotics may prolong shedding and increase the likelihood of recurrence.

Question 32

What is the lifestyle of Salmonella in host cells?

Answer 32

Facultative intracellular lifestyle; can invade host cells but does not require it for replication. ## Footnote This flexibility allows Salmonella to thrive in various environments.

Question 33

What are the two species of Salmonella mentioned?

Answer 33

S. enterica and S. bongori. ## Footnote S. enterica is the most common in disease, occurring 99.9% of the time.

Question 34

What is Typhoid disease caused by?

Answer 34

Typhi and Paratyphi serovars. ## Footnote It is a host-restricted septicemic disease in humans.

Question 35

What characterizes non-Typhoidal Salmonella infections?

Answer 35

Any human salmonellosis caused by serovars other than Typhi and Paratyphi. ## Footnote These infections can arise from various sources.

Question 36

How resilient is Salmonella in the environment?

Answer 36

Very hearty; can last for years and is labile to most common disinfectants. ## Footnote This resilience contributes to its spread and persistence.

Question 37

What is 'clonal replacement' in the context of Salmonella?

Answer 37

Predominant serotypes change over time due to clonal replacement. ## Footnote This phenomenon can affect outbreak patterns and control measures.

Question 38

What economic impact does S. Enteritidis have?

Answer 38

Massive economic impact on egg producers due to recalls. ## Footnote This serotype is associated with foodborne illness outbreaks.