Actinomyces osteomyelitis in bisphosphonate-related osteonecrosis of the jaw (BRONJ): the missing link?

Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a rare complication of bisphosphonate treatment characterized by the development of exposed, necrotic bone in the jaw with inflammatory signs. The pathogenesis of BRONJ is not yet fully understood. This review analyzes the evidence supporting the hypothesis that BRONJ may be considered as a bisphosphonate-induced Actinomyces infection of the jaw according to the modified Koch's postulates. The main arguments relies on the following factors: (1) the high prevalence of isolation of Actinomyces from bone BRONJ lesions (73.2 % in retrospective series); (2) the similar pathological appearance of BRONJ and Actinomyces osteomyelitis in most studies, although BRONJ lesions without inflammation have been reported; (3) the high incidence of events that disrupt the normal mucosal barrier as a necessary trigger to develop BRONJ in bisphosphonate-exposed patients; (4) the predilection of bisphosphonate-induced osteonecrosis for the bones of the jaws; and (5) the favorable response of BRONJ on treatment that is active on Actinomyces. If BRONJ confirms to be a bisphosphonate-induced Actinomyces osteomyelitis of the jaw, this has major consequences for the prevention and treatment of this condition.

Cutaneous actinomycosis associated with anti-TNF-alpha therapy: report of two cases.

Increased susceptibility to infections is among the main safety concerns raised by anti-TNF-α agents. We describe two cases of cutaneous actinomycosis in patients undergoing anti-TNF-α therapy: a 49-year-old female treated with etanercept for rheumatoid arthritis and a 57-year-old female treated with infliximab for psoriasis. Both patients had discharge with the intermittent presence of sulfur granules occurring at the site of previous surgical wounds. Bacteriological culture demonstrated Actinomyces. Since in both cases laboratory findings and medical imaging ruled out visceral actinomycosis, oral antibiotics were introduced without discontinuing anti-TNF-α. The first patient did not relapse after 2 years. The second one did and received a second course of antibiotics combined with transient interruption of the anti-TNF-α therapy. The risk of developing actinomycosis is reported to be similar in immunocompetent and immunocompromised patients, however cases of cutaneous actinomycosis occurring during anti-TNF-α therapy need to be recognized and may be under-reported.

Pulmonary actinomycosis complicating infliximab therapy for Crohn's disease.

The use of anti-tumour necrosis factor (TNF) agents has expanded significantly over the past few years, particularly for rheumatological diseases and Crohn's disease. A number of associated opportunistic infections have been observed as a result of suppression of T cell-mediated immunity, the most frequent being tuberculosis. We report the first case of pulmonary actinomycosis in a patient receiving regular infusions of infliximab, an anti-TNF agent, for Crohn's disease.

Experimental oral chronic infection induced by actinomyces israelii and propionibacterium acnes

The purpose of this study was to evaluate an experimental animal model of oral chronic infection induced by Actinomyces israelii and propionibacterium acnes in mice. Swiss/NIH mice (n=100), 21 days of age, male and female were divided into two groups of 45 animals. A. israelii (n=45) and P. acnes (n=45) were inoculated in the anterior mandibular paraperiosteal periodontal tissue associated with sodium alginate gel particles. The animals were evaluated clinically and microscopically at 1,3,7,15,21,30 and 45 days after inoculation. Actinomycotic and propioni lesions were induced in all animals. In control mice (n=10), no lesions were noted; however, differences in the clinical and histopathological evoluations of actinomycosis and propioni lesions were observed and are discussed in this study. Microorganisms entrapped in alginate gel provided a prolonged bacterial irritation, and chronic histopathologic features similar to those seen in human actinomycosis could be detected.

Infecção oral crônica experimental induzida por actinomyces israelii e propionibacterium acnes / Experimental oral chronic infection induced by actinomyces israelii and propionibacterium acnes

The purpose of this study was to evaluate an experimental animal model of oral chronic infection induced by Actinomyces israelii and propionibacterium acnes in mice. Swiss/NIH mice (n=100), 21 days of age, male and female were divided into two groups of 45 animals. A. israelii (n=45)and P. acnes (n=45) were inoculated in the anterior mandibular paraperiosteal periodontal tissue associated with sodium alginate gel particles. The animals were evaluated clinically and microscopically at 1,3,7,15,21,30 and 45 days after inoculation. Actinomycotic and propioni lesions were induced in all animals. In control mice (n=10), no lesions were noted; however, differences in the clinical and histopathological evoluations of actinomycosis and propioni lesions were observed and are discussed in this study. Microorganisms entrapped in alginate gel provided a prolonged bacterial irritation, and chronic histopathologic features similar to those seen in human actinomycosis could be detected.

Splenic actinomycotic abscess in a patient with acute myeloid leukemia.

Actinomycosis is a gram-positive anaerobic bacterium. Actinomyces organisms are important constituents of the normal flora of mucous membranes and are considered opportunistic pathogens. The three major clinical presentations of actinomycosis include the cervicofacial, thoracic, and abdominopelvic regions. Actinomycosis infection in patients with febrile neutropenia is uncommon and actinomycosis splenic involvement in acute leukemia patients is very rare. We describe a man with acute myeloid leukemia and splenic actinomycotic abscess that developed after chemotherapy following prolonged neutropenia.

[Tubo-ovarian actinomycosis, intrauterine device and chemotherapy for breast cancer]. / Actinomycose tubo-ovarienne, stérilet et chimothérapie pour cancer du sein.

Tubo-ovarian actinomycosis was observed after chemotherapy for breast cancer in a patient with an intrauterine device. Does chemotherapy increase the risk? How can it be prevented?