Pathogens characteristics

Question 1

Which pathogens are gram-positive?

Answer 1

1. S. aureus
2. L. mono
3. B. cereus
4. Cl. perfinigens
5. Cl. botulinum

Question 2

Which pathogens are gram-negative?

Answer 2

1. Salmonella
2. Campylobacter
3. Vibrio para
4. E coli

Question 3

Which pathogens are rod shaped?

Answer 3

All except for Campy (spiral shape), Vibrio parah (spiral), Staphylo coccus (cocc)

Question 4

Which pathogens induce a foodborne intoxication?

Answer 4

Staphylococcus aureus, Cl. Botulinum, B. cereus (both infect and intox). The rest of the pathogens are infectious.

Question 5

What is the most common dose/resp? And what are the divergent ones?

Answer 5

The most common dose/resp is 10^5 CFU/gram or /mL, which is for all pathogens except for:
- Campy with 100 CFU/gram or /mL
- Cl. Botulinum with ?
- E. coli with 10 CFU/mL

Question 6

What kind of temperature preference do most pathogens have? And what are the divergent ones?

Answer 6

All pathogens are mesophiles (5-45 degrees), except for Campylobacter (mesophile but 30-45) and L. mono (psychrotolerant/mesophile 0-45)

Question 7

What is the pH preference of most bacteria and which one is the outlier?

Answer 7

They are neutrophillic with pH around 5-8, the outlier is E. coli with 3-8 (because found in the gut which is acidic).

Question 8

What is the most common oxygen preference of the pathogens, and which ones are the outliers?

Answer 8

Most pathogens are facultative anaerobe (they can grow without O2, but grow better with it). Except for:
- Campylobacter, which is microaerophilic (damaged by atm O2).
- B. cereus which is fac. aerobe (grows better without oxygen)
- Clostridium bot. and perf. are obligate anaerobe, they cannot tolerate O2 and die

Question 9

Which pathogens can survive dry conditions?

Answer 9

All except for campylobacter and V. parah