Which of the following scenarios are examples of an opportunistic pathogen causing infection?SELECT ALL THAT APPLYBacillus anthracis causing anthrax following exposureE. coli from the appendix entering the peritoneum and causing infectionShigella dysenteriae causing diarrhea and dysentery following ingestionMycobacterium tuberculosis causing tuberculosis following respiratory exposureCandida albicans causing thrush after treatment with antibioticsStreptococcus pyogenes causing strep throat or pharyngitis

An opportunistic pathogen is an organism that causes an infection in its host with a compromised immune system or when it has entered an unusual area of the body.

1. Bacillus anthracis causing anthrax following exposure: This is not an example of an opportunistic pathogen. Bacillus anthracis is a primary pathogen that can cause disease in healthy individuals.

2. E. coli from the appendix entering the peritoneum and causing infection: This is an example of an opportunistic pathogen. E. coli is part of the normal gut flora and only causes disease when it enters a site where it is not usually found, like the peritoneum.

3. Shigella dysenteriae causing diarrhea and dysentery following ingestion: This is not an example of an opportunistic pathogen. Shigella dysenteriae is a primary pathogen that can cause disease in healthy individuals.

4. Mycobacterium tuberculosis causing tuberculosis following respiratory exposure: This is not an example of an opportunistic pathogen. Mycobacterium tuberculosis is a primary pathogen that can cause disease in healthy individuals.

5. Candida albicans causing thrush after treatment with antibiotics: This is an example of an opportunistic pathogen. Candida albicans is part of the normal flora of the mouth, skin, and vagina and only causes disease when the normal balance of flora is disrupted, such as after antibiotic treatment.

6. Streptococcus pyogenes causing strep throat or pharyngitis: This is not an example of an opportunistic pathogen. Streptococcus pyogenes is a primary pathogen that can cause disease in healthy individuals.

So, the scenarios that are examples of an opportunistic pathogen causing infection are E. coli from the appendix entering the peritoneum and causing infection, and Candida albicans causing thrush after treatment with antibiotics.