Actinomyces | ||
Agents: | Agents of actinomycosis | N. asteroides complex and other species |
Gram stain: | Filamentous or beaded/branching, Gram-positive bacillus | Filamentous Gram-positive bacillus |
Modified AFB: | Negative | Positive (weakly) |
Source: | Mouth, GI or GU flora | Soil |
Typical Hosts: | Previously healthy or co-morbidities (e.g., diabetes), poor dentition | Decreased cell-mediated immunity Occasionally strikes immunocompetent |
Clinical features: | Indurated tissue, fistula or sinus track with sulfur granules | Indurated with sulfur granules |
Course: | Indolent | Subacute to Indolent |
Rx: | Penicillin G, ampicillin/amoxicillin, antipseudomonal PCNs, most cephalosporins, macrolides, tetracycline, imipenem, clindamycin |
Drug | Recommendation |
Neither cefotaxime nor ceftriaxone was usually selected for Actinomyces infection, but the limited experience is quite good. The main reason for selection is the perceived need to treat other pathogens; these drugs are reasonable in this context. | |
A good drug for actinomycosis - good in vitro activity and a limited but very favorable published experience in vivo. As with penicillin - it needs high doses and a long course. High risk for C diff., so PCN is usually preferred. | |
A good drug for actinomycosis. The agents are susceptible, and clinical experience seems good. An advantage is the availability of oral and parenteral forms. Some clinicians will start therapy with high IV doses of penicillin or clindamycin and use doxycycline for a prolonged oral maintenance phase. | |
A good drug for actinomycosis. The published experience includes anecdotal cases with large thoracic lesions that resolved. | |
This drug won’t work. Actinomyces are not susceptible in vitro. This means Actinomycetes are probably not true anaerobes. | |
Penicillin G: standard drug for actinomycosis. Need high doses given IV to penetrate a very fibrotic and dense lesion. The course must be long to achieve resolution and prevent relapse. | |
Preferred by some to penicillin G for parenteral therapy. For OPAT, the drug is less stable and needs to be kept refrigerated or mixed just before administration, so typically, Penicillin G is selected. | |
Preferred drug for oral treatment--either initially for mild-moderate infections or maintenance therapy after the initial parenteral course. |
Comment: The disease is defined by location. Cervicofacial is most common, then thoracic and abdominopelvic. Path -- crosses tissue planes and causes sinus tracts. It often mimics tumors and other infections with its imaging and clinical features. Treatment is a long course of antibiotics.
Comment: Four unusual cases out of 15 at two institutions: subcutaneous actinomycotic abscess, actinomycosis of the stomach with underlying non-Hodgkin lymphoma, sepsis due to Actinomyces neslundii originated from chronic asymptomatic periapical tooth abscesses and actinomycosis of the distal part of the penile shaft.
Comment: A rare cause of infection in PWID, but endocarditis, septic pulmonary emboli or thrombophlebitis, soft tissue abscesses and prosthetic joint infections are described. In this series, blood cultures were positive in three patients.
Comment: In vitro data is often hard to come by with this organism. Organisms are almost always susceptible to beta-lactam antibiotics (without the need for beta-lactamase inhibitors), tetracyclines and vancomycin.
Comment: Case report of an 8-year-old patient with pneumonia complicated by empyema necessitatis. Culture yielded A. israelii and A. actinomycetccomitans. Treatment was drainage and doxycycline for one year.
Comment: Comprehensive overview of the significance of Actinomyces in human infections.
Rating: Important
Comment: CT anatomical features: parenchymal, bronchiectatic, endobronchial and extrapulmonary.
Rating: Important
Comment: Different than the usual actino--aerobic growth, microscopic morphology (no branching), and the types and location of infections. Abscesses and infected atheromas are the most frequent types of infections, followed by infected skin structures, endophthalmitis, and bacteremias, including endocarditis. This organism appears to have susceptibility profile similar to other members.
Comment: Review of 40 cases of thoracic actinomycosis -- 17 had immediate surgery due to hemoptysis or concern for cancer. Antibiotic therapy for the other 23 was successful in 18 (78%); 5 failed and required surgery. The antibiotic failures received these drugs on an average of 10 months, but those who responded showed improvement within two months.
Rating: Important
Comment: Case report of endobronchial actinomyces associated with a fish bone swallowed 28 months before detection.
Comment: Case report -- abdominal wall mass treated with long course of penicillin for actinomycosis. Due to poor response the patient had surgical excision which the authors noted is indicated for suboptimal response or a malignant process cannot be ruled out.
Rating: Important
Comment: Review of recent evidence that actinomycosis is a significant factor in infected osteoradionecrosis and bisphosphonate-associated osteonecrosis of jaws. A. graevenitzii may be the causative agent. Diagnosis is based on histopathology.
Rating: Important
Comment: Three cases were initially diagnosed as pelvic malignancy and treated surgically. The review noted the association with IUD, the mistake of aggressive surgery for presumed malignancy and the diagnosis based on histopathology
Comment: Authors reviewed archived material for actinomycosis of jaws and found bisphosphonate-associated osteonecrosis (BON) in 60% and infected osteoradionecrosis (IORN) in 36%. All cases showed actinomyces colonies in bone. PCR indicated A. israeli in 7 of 7 decalcified tissue specimens.
Rating: Important
Comment: Authors call attention to the common features of actinomyces and nocardiosis - both often cause chronic lung disease that simulates lung cancer or TB.
Comment: Chronic pulmonary actinomycosis typically presents as a segmental consolidation with frequent cavity formation. A broncholith can be secondarily infected, resulting in endobronchial actinomycosis, often with distal obstructive pneumonia.
Comment: Actinomycetes were the most common bacteria on failed dental implants -A. odontolyticus > A. naeslundii = A. viscosus > A. israelii; A. georgiae, A. geroneseriae and A. graevenitzii were rare.
Comment: Eighty-seven strains tested to 12 antibiotics. All were sensitive to penicillin, ampicillin and beta-lactam/beta-lactamase inhibitors. All were resistant to ciprofloxacin. Linezolid showed good activity.
Rating: Important
Comment: The authors argue that treatment may be < 6 months based on their experience with two cases (esophageal and cervicofacial).
Rating: Important
Comment: In these 1997 cases, the predominant species were A. israelii (41%), A. gerencseriae (27%), A. naeslundii (9%), A. odontolyticus (1%), and P. propionicum (1%).
Rating: Important
Comment: The authors review 18 cases. GI lesions showed concentric or eccentric bowel wall thickening; 17 pts had a pelvic or peritoneal mass with a mean diameter of 3.2cm adjacent to the involved bowel. Clinical features included abd pain, fever, leukocytosis & long-term IUD use.
Comment: This is the third reported case of A. viscosus endocarditis, although many cases involving other Actinomyces have been reported. All cases have involved natural valves, and there appears to be a high frequency of embolic lesions.
Comment: A review of 22 cases resulted in the following definition of typical CT findings: chronic segmental air-space consolidation that contains low-attenuation areas with peripheral enhancement or adjacent pleural thickening.
Comment: Diagnostic methods include 1) cultivation of the microbe (which is hard to do); 2) typical appearance on gram stain, especially with sulfur granules; and 3) fluorescent antibody (FA) stains that are available for 4 of the 6 agents of actinomycosis.
Rating: Important
Comment: A survey of 69,925 women with pap smear screened for actino with FA stain for A. israelii showed the prevalence in those with IUD use was 1.6-5.3%; it was never found in the absence of an IUD. It should be noted that the rates of A. israelii with IUDs were high, but the rate of pelvic actinomycosis was much lower.
Rating: Important
Pulmonary thoracic actinomyces eroding through chest wall; Source: PG Auwaerter MD
Sulfur granules from chest wall sinus tract
Source: PG Auwaerter MD
Colonies of actinomyces make up sulphur granules. Source: CDC/ Dr. Richard L. Levin, Greater Southeast Community Hospital, Washington, D.C.; Dr. V.R. Dowell |
Gram-positive, beaded and branching rods (magnification 1125x) characteristic of actinomyces. Specimen from jaw area, often organisms may not grow in laboratory. Source: CDC/ Dr. Lucille Georg
Actinomycosis causing chronic swelling and a sinus tract.
Source: CDC/Dr. Thomas F. Sellers/Emory University 1963