Microbiology Practice Exam 2025 – Complete Study Resource

The method commonly used to culture anaerobic bacteria is thioglycolate broth. This medium contains sodium thioglycolate, which reduces oxygen tension, creating an anaerobic environment conducive for the growth of anaerobes. It allows for the cultivation of both aerobic and anaerobic organisms due to its gradient of oxygen concentration; anaerobes thrive in the lower oxygen conditions at the bottom of the broth where oxygen is depleted, while facultative anaerobes and aerobic bacteria can grow higher up in the medium where oxygen is still present.

Blood agar plates, while rich in nutrients and suitable for many bacteria, are generally used for culturing aerobic and facultatively anaerobic bacteria, as they do not create a controlled anaerobic environment. Nutrient agar is a general-purpose medium that also supports aerobic growth and does not specifically facilitate anaerobic conditions. Sabouraud agar is formulated mainly for fungal growth and is not suitable for culturing anaerobic bacteria. Thus, thioglycolate broth stands out as the appropriate choice for culturing anaerobic bacteria due to its design to maintain low or no oxygen levels.