Is Actinomyces gram-positive or negative?

Is Actinomyces gram-positive or negative?

Actinomyces spp. are filamentous Gram-positive bacilli, mainly belonging to the human commensal flora of the oropharynx, gastrointestinal tract, and urogenital tract.

Is Actinomyces a Gram-positive bacteria?

Actinomyces and P propionicum are irregular, nonspore-forming, Gram-positive rods. Actinomyces contains 19 species (Table 34-1), of which A israelii and A gerencseriae are the most common human pathogens.

Is Actinomyces gram-positive cocci?

Actinomyces are gram-positive filamentous bacilli. Their branching, filamentous morphology gives them a fungal-like appearance and is the origin of their name, from the Greek actis (ray or beam), and mykes (fungus).

Is Actinomyces gram negative?

Actinomyces species are gram-positive anaerobic bacteria that are normal inhabitants of the mouth and bowel.

Is Actinomyces aerobic or anaerobic?

Actinomyces species are facultative, anaerobic, non–spore-forming, filamentous, gram-positive rods that commonly inhabit the oropharynx. Although individual bacteria are filamentous, colonies form fungus-like branched networks of hyphae.

Is Actinomyces a contaminant?

In addition to those organisms, which are classically seen as contaminants in blood cultures, Staphylococcus aureus, Enterococcus faecalis, and Escherichia coli were identified with the Actinomyces isolates; in all of those cases, the patients were treated for those organisms even if no action was taken with respect to …

Are actinomycetes catalase positive?

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

Is Fusobacterium gram-positive or negative?

Fusobacteria are anaerobic gram-negative rods that are a rare cause of serious human disease [1, 2]. Two Fusobacterium species, F. nucleatum and F. necrophorum, are the most commonly isolated pathogens within this genus [2, 3].

Does GMS stain Actinomyces?

Recall that GMS stains all Gram-positive organisms and with no specificity for actinomycosis.

What stain is used for Actinomyces?

When faced with gram-positive, Gomori Methenamine Silver-positive filamentous bacteria, the use of a modified acid fast stain is an excellent method for distinguishing between Nocardia and Actinomyces species.

Is Actinomyces aerobic?

Actinomycetes are a group of aerobic and anaerobic bacteria in the order Actinomycetales. These organisms are phylogenetically diverse but morphologically similar, exhibiting characteristic filamentous branching structures which then fragment into bacillary or coccoid forms (1) (Figure 1).