MIDTERMS: Anaerobic Bacteriology and Sporeformers

What is the main reason obligate anaerobes are killed by oxygen?

• They use oxygen as a final electron acceptor

• They lack cytochrome systems and catalase

• They are facultative aerobes

• They produce toxins in oxygen

Which test tube location would obligate anaerobes grow in thioglycolate broth?

• Top

• Middle

• Bottom

• Throughout

What enzyme is commonly absent in obligate anaerobes?

• Lactase

• Amylase

• Catalase

• Kinase

Which bacteria tolerate oxygen but do not use it for metabolism?

• Obligate anaerobes

• Facultative anaerobes

• Microaerophiles

• Aerotolerant anaerobes

What is the function of the GasPak envelope in an anaerobic jar?

• Provides nutrients

• Releases oxygen

• Generates CO₂ and H₂

• Absorbs carbon dioxide

Which reducing agent is used in anaerobic culture media?

• Chloride

• Cysteine

• Sucrose

• Maltose

Which culture medium supports anaerobic growth?

• MacConkey agar

• Sabouraud agar

• Schaedler’s blood agar

• Mannitol salt agar

What indicator is used to detect the presence of oxygen in an anaerobic jar?

• Phenol red

• Resazurin

• Bromothymol blue

• Crystal violet

What does a pink resazurin strip indicate?

• No oxygen

• Anaerobic environment

• Presence of oxygen

• High humidity

In polymicrobic infections, anaerobes often co-exist with:

• Mycobacteria

• Facultative anaerobes

• Viruses

• Algae