Is Actinomyces catalase positive?

Actinomyces radicidentis are catalase positive and give variable results on nitrate and urease tests.

Is Actinomyces catalase negative?

Actinomyces spp. are filamentous, branching, gram-positive, pleomorphic, non–spore-forming, catalase-negative, anaerobic or microaerophilic/capnophilic bacilli.

Does Actinomyces grow on blood agar?

Actinomyces can be cultured on chocolate blood agar media at 37°C. Other enriched media can be used for Actinomyces isolation: brain heart infusion broth and Brucella Blood Agar with hemin and vitamin K1.

How can you tell the difference between Actinomyces and Nocardia?

Actinomyces are part of the normal flora of the mouth and gastrointestinal tract and are generally low virulence. In contrast, Nocardia are saprophytic organisms with a worldwide distribution in soil. Human infections result from direct inoculation of the skin or soft tissue or by inhalation of contaminated soil.

What do you need to know about actinomycosis?

Abstract. Actinomycosis is a rare chronic disease caused by Actinomyces spp., anaerobic Gram-positive bacteria that normally colonize the human mouth and digestive and genital tracts. Physicians must be aware of typical clinical presentations (such as cervicofacial actinomycosis following dental focus of infection,…

How is the definitive identification of Actinomyces odontolyticus made?

Definitive identification is made by negative catalase and oxidase tests, the reduction of nitrate to nitrite, filamentation of microcolonies, and absence of growth at pH 5.5. Generally, the fermentation reactions are variable.

How are Actinomyces isolated from root surface caries?

Actinomyces species are isolated from supragingival plaques and root surface caries, and they are implicated in the development of gingivitis. 32 Infection can spread when normal mucosal barriers are disrupted, leading to abscesses with connecting sinus tracts.

What causes granular texture in Actinomyces exudates?

Microscopic examination of pus reveals exudates with granular texture caused by sulfur granules, resulting from the bacterium and its waste. A. israelii is most commonly associated with actinomycosis; however, other Actinomyces bacteria are capable of causing disease.