What type of organism is Actinomyces israelii?

Actinomyces israelii is classified as a Gram-positive non-acid fast anaerobic obligate rod. This organism belongs to the Actinobacteria class and is primarily found in human mucosal surfaces, playing a role in the normal flora of the mouth and the gastrointestinal tract.

The Gram-positive nature means that it retains the crystal violet stain used in the Gram staining procedure, which is indicative of a thicker peptidoglycan layer in the bacterial cell wall compared to Gram-negative bacteria. Being non-acid fast further confirms that it does not possess mycolic acids in its cell wall, which are characteristic of acid-fast bacteria like Mycobacterium species.

Furthermore, Actinomyces israelii is anaerobic and obligate, meaning it thrives in environments devoid of oxygen and is unable to grow in aerobic conditions. This helps to understand the typical infections associated with this organism, which often occur in anaerobic conditions within the body, such as in abscesses or chronic infections.

The characteristics of this organism are critical, especially in clinical settings, where its identification can aid in understanding the potential for certain types of infections and guide appropriate therapeutic interventions.