Is Actinomyces gram-positive or negative?
Actinomyces are non-spore-forming Gram-positive rods. Except for A. meyeri, which is small and nonbranching, all the other species are branching filamentous rods. Growth of Actinomyces is slow; it appears within at least 5 days and may take up to 15–20 days.
Is Actinomyces gram-positive cocci?
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 Neuii catalase positive?
Actinomyces radicidentis are catalase positive and give variable results on nitrate and urease tests.
What happens if leaving actinomycosis untreated?
Actinomycosis starts in the soft tissues of the body, but it can infect any surrounding bone if it’s left untreated. Surgery may be necessary to remove any infected bone. If the infection resides in the nasal sinuses, surgery may be required to remove damaged bone and tissue.
How is actinomycosis treated?
Conventional therapy for actinomycosis is high-dose intravenous penicillin at a dosage of 18–24 million U daily for 2–6 weeks, followed by oral penicillin or amoxicillin for a period of 6–12 months [1, 2].
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,…
What kind of bacteria are in Gram positive blood cultures?
The gram positive species include cocci (Peptostreptococcus spp.) and rods (Actinomyces, Bifidobacterium, Eubacterium, Lactobacillus, Clostridium and Propionibacterium species). The gram negatives (only rods, no cocci) include Prevotella, Porphyromonas, Fusobacterium and Bacteroide s species).
What kind of Media do you use to culture Actinomyces?
Most Actinomyces spp. are facultative anaerobes, but some relevant species (such as A. meyeri), are strictly anaerobic, so cultures must be incubated in an anaerobic atmosphere. Actinomyces can be cultured on chocolate blood agar media at 37°C.
Which is more effective against Gram positive anaerobic bacteria?
Most Gram-positive anaerobic cocci are normally susceptible to penicillins and β-lactam/β-lactamase inhibitor combinations. Clindamycin and metronidazole are less active against Gram-positive anaerobic cocci but can be used in most infections (17).
