Actinomycosis is a rare chronic disease caused by Actinomyces spp. Physicians must be aware of typical clinical presentations such as cervicofacial actinomycosis following dental focus of infection, pelvic actinomycosis in women with an intrauterine device, and pulmonary actinomycosis in smokers with poor dental hygiene , but also that actinomycosis may mimic the malignancy process in various anatomical sites. Bacterial cultures and pathology are the cornerstone of diagnosis, but particular conditions are required in order to get the correct diagnosis. Prolonged bacterial cultures in anaerobic conditions are necessary to identify the bacterium and typical microscopic findings include necrosis with yellowish sulfur granules and filamentous Gram-positive fungal-like pathogens. Patients with actinomycosis require prolonged 6- to month high doses to facilitate the drug penetration in abscess and in infected tissues of penicillin G or amoxicillin, but the duration of antimicrobial therapy could probably be shortened to 3 months in patients in whom optimal surgical resection of infected tissues has been performed. Preventive measures, such as reduction of alcohol abuse and improvement of dental hygiene, may limit occurrence of pulmonary, cervicofacial, and central nervous system actinomycosis.
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Actinomycosis is a rare chronic disease caused by Actinomyces spp. Physicians must be aware of typical clinical presentations such as cervicofacial actinomycosis following dental focus of infection, pelvic actinomycosis in women with an intrauterine device, and pulmonary actinomycosis in smokers with poor dental hygiene , but also that actinomycosis may mimic the malignancy process in various anatomical sites. Bacterial cultures and pathology are the cornerstone of diagnosis, but particular conditions are required in order to get the correct diagnosis.
Prolonged bacterial cultures in anaerobic conditions are necessary to identify the bacterium and typical microscopic findings include necrosis with yellowish sulfur granules and filamentous Gram-positive fungal-like pathogens. Patients with actinomycosis require prolonged 6- to month high doses to facilitate the drug penetration in abscess and in infected tissues of penicillin G or amoxicillin, but the duration of antimicrobial therapy could probably be shortened to 3 months in patients in whom optimal surgical resection of infected tissues has been performed.
Preventive measures, such as reduction of alcohol abuse and improvement of dental hygiene, may limit occurrence of pulmonary, cervicofacial, and central nervous system actinomycosis.
In women, intrauterine devices must be changed every 5 years in order to limit the occurrence of pelvic actinomycosis. Actinomycosis is an infrequent invasive bacterial disease that has been recognized for over a century.
Actinomyces spp. To date, multiple different clinical features of actinomycosis have been described, as various anatomical sites such as face, bone and joint, respiratory tract, genitourinary tract, digestive tract, central nervous system, skin, and soft tissue structures can be affected.
Of note, in any site, actinomycosis frequently mimics malignancy, tuberculosis, or nocardiosis, as it spreads continuously and progressively, and often forms a cold abscess. In this review, we aim to describe: 1 the overview of the different species of Actinomyces ; 2 their involvement in different clinical features with illustrative cases; and 3 key elements for the diagnosis, ie, bacterial cultures and pathology; and 4 current and emerging treatment options.
Bacteria of the genus Actinomyces belong to the Actinobacteria phylum and Actinomycetales order and are related to other genera such as Corynebacterium , Mycobacterium , Nocardia , and Propionibacterium. Besides Actinomyces , Propionibacterium propionicum formerly Arachnia propionica , has often been reported as an agent of actinomycosis-like infections. Actinomyces israelii is the most prevalent species isolated in human infections and is found in most clinical forms of actinomycosis.
Some species, including Actinomyces naeslundii , Actinomyces odontolyticus , Actinomyces gerencseriae formerly A. Therefore Actinomyces are often isolated with other normal commensals, such as Aggregatibacter actinomycetemcomitans , Eikenella corrodens , Capnocytophaga , fusobacteria, Bacteroides , staphylococci, streptococci, or Enterobacteriaceae, depending on the site of infection.
The bacteriological identification of Actinomyces from a sterile site confirms the diagnosis of actinomycosis. The most appropriate clinical specimens are tissue from surgical biopsy or pus; swabs must be avoided. Finally, clinicians should indicate suspicion for actinomycosis to the microbiologist to ensure that prolonged culture on appropriate media and in an appropriate atmosphere is performed.
A Gram stain of the specimen is usually more sensitive than culture, especially if the patient had received antibiotics. Actinomyces are non-spore-forming Gram-positive rods. Except for A. Growth of Actinomyces is slow; it appears within at least 5 days and may take up to 15—20 days. Thus, incubation of at least 10 days is required before conclusion of a negative culture.
Most Actinomyces spp. Other enriched media can be used for Actinomyces isolation: brain heart infusion broth and Brucella Blood Agar with hemin and vitamin K1.
The use of semi-selective media such as phenylethyl alcohol or mupirocin-metronidazole blood agar may increase isolation rates by inhibiting overgrowth of concomitant organisms. For example, A. Actinomyces are indole-negative bacteria.
Identification was classically based on phenotypic tests urease, catalase, fermentation of sugars, etc or on commercial biochemical kits but, in fact, such tests can lead to misidentification of species and even of genus. The classification of Actinomyces spp. Therefore, nowadays, molecular techniques such as 16S rRNA sequencing serve as the reference for identification. Mass spectrometry uses an ionization source to charge and separate ionized bacterial proteins; then, a detector and mass analyzer generate a mass spectrum specific to bacterial species.
Concerning Actinomyces , MALDI-TOF allows accurate identification at the genus level, but species identification remains uncertain and depends on the mass spectrometry system and the species studied. Once Actinomyces spp. These formations of 0. Yellowish sulfur granules are constituted by conglomeration of bacteria trapped in biofilm.
These findings are highly suggestive of the diagnosis but are not specific, as they can be encountered in other pathogenic conditions such as nocardiosis or chronic cervicofacial fungal infections. However, Gram staining can additionally show Gram-positive filamentous branching bacteria at the periphery of the granule that is highly suggestive of actinomycosis. Immunofluorescence techniques have poor sensitivity but are highly specific in the diagnosis.
Drug resistance is not considered a problem in actinomycosis. Indeed, Actinomyces spp. As a consequence, penicillin G or amoxicillin are considered drugs of choice for the treatment of actinomycosis. Third-generation cephalosporins are less frequently used even if they are considered to be active on A.
Oxacillin, cloxacillin, and cephalexin, a first-generation cephalosporin, are not considered to be active. Metronidazole and aminoglycosides have no in vitro activity against Actinomyces. Fluoroquinolones ciprofloxacin and moxifloxacin are usually considered to be inactive, but data are limited and controversial.
Doxycycline is considered to have a poor activity on Actinomyces spp. Macrolides and clindamycin have been used successfully as alternatives. As Actinomyces spp. Respiratory tract actinomycosis includes pulmonary, bronchial, and laryngeal actinomycosis. Pulmonary actinomycosis is the third most common type of actinomycosis, after that occurring in cervicofacial and abdominopelvic locations. In children, pulmonary involvement is uncommon. At early stages of the disease, a focal pulmonary consolidation occurs, which can be surrounded by pulmonary nodules, but there are often no associated physical symptoms at this stage.
This primary pulmonary involvement could secondly lead to constitution of a peripheral mass, with or without cavitation, which could invade adjacent tissue. Bronchial actinomycosis is rare. It may occur after disruption of the mucosal barrier, especially in patients with endobronchial stent, or with a bronchial foreign body aspiration for example, of a fish bone.
Concerning laryngeal actinomycosis, various different forms have been described. Vocal cord actinomycosis may mimic primary carcinoma or papilloma, whereas in patients with past history of laryngeal carcinoma and radiotherapy, actinomycosis may mimic laryngeal cancer relapse, as it may present as an ulcerative lesion, most often without abscess or sinus tract.
A year-old woman presented with a 5-month history of chronic sinusitis without fever 1 year after allogeneic allograft bone marrow transplant for idiopathic aplasia. Computed tomography CT scan revealed right maxillary sinusitis and left focal basal pneumonia, without cavitation Figure 1. Bronchoalveolar fluid BAL revealed Actinomyces spp. The patient responded well to right maxillary antrostomy and high doses of intravenous and then oral amoxicillin for 5 months.
Computed tomography scan revealing a right maxillary sinusitis A and left focal basal pneumonia without cavitation B , due to Actinomyces spp. A year-old man with long-term tobacco and alcohol abuse was admitted for asthenia and loss of 20 kg in 6 months. The patient had had a cough for several months, but never experienced hemoptysis. Physical examination revealed a right pulmonary crackling sound.
A sinus tract, which followed a 3-week history of subcutaneous abscess, was observed in the right face of the thorax. Chest X-ray and CT scan revealed multifocal pneumonia with right pleural cavitation, in the face of the sinus tract Figure 2. BAL revealed A. The patient responded well to prolonged amoxicillin therapy 9 months. Chest X-ray A and thorax computed tomography scan B — C revealing multifocal pneumonia with right pleural cavitation due to Actinomyces viscosus.
Pulmonary actinomycosis could be acute or subacute, with lobar pulmonary involvement. However, the disease is mostly diagnosed at the chronic phase, in patients presenting mild fever and weight loss. The most common symptoms are nonspecific, similar to those of other chronic lung infections such as tuberculosis or thoracic cancer: productive cough, hemoptysis, dyspnea, and chest pain.
Gradually, the pulmonary mass becomes soft and fluctuant, with a purulent center, which could be followed by cavitation. Cavitation may occur in patients with purulent discharge in bronchi, mimicking tuberculosis. Cavitation may also occur in patients with spontaneous drainage through the chest wall, forming a sinus tract. Patients with pulmonary cavitation associated with a chest-wall sinus tract should lead the physician to suspect actinomycosis.
Imaging of pulmonary actinomycosis is not specific, and pulmonary actinomycosis is frequently confused with malignancy mass or tuberculosis cavitation. The main CT findings are consolidation, lymph node enlargement, atelectasis, cavitation, ground glass opacity, and pleural effusion. There is no preferential localization in the lung. The gold standard for diagnosing pulmonary actinomycosis is histological examination and bacterial culture of a lung biopsy, obtained by percutaneous biopsy guided by CT scan or by open surgical resection.
Bronchoscopy should be performed to exclude malignancy. Simple culture of Actinomyces in BAL, as with sputum, is inappropriate for the diagnosis of pulmonary actinomycosis, except for patients with cavitation, as it may represent colonization. Patients with pulmonary actinomycosis require prolonged high doses of antimicrobial therapy with beta-lactam antibiotics, and penicillin G, cephalosporin, or amoxicillin are frequently used.
For instance, it is recommended to intravenously administer a dose of 18—24 million units per day of penicillin G over 2—6 weeks, followed by oral therapy with penicillin V or amoxicillin for 6—12 months.
Actinomyces are commensals of the human oropharynx, and are particularly prevalent within gingival crevices, tonsillar crypts, periodontal pockets and dental plaques, as well as on carious teeth. Consequently, actinomycosis is mainly considered an endogenous infection that is triggered by a mucosal lesion. Finally, cervicofacial actinomycosis can lead to distant organ dissemination, including brain, lungs, and digestive tract. Cervicofacial actinomycosis is a relatively rare condition worldwide, with no predilection for age, race, season, or occupation.
Physiopathological pathways of cervicofacial actinomycosis explain that predisposing conditions include poor oral hygiene dental caries, gingivitis, infection in erupting secondary teeth and oral mucosa trauma dental extraction, gingival trauma, local tissue damage caused by neoplastic condition or irradiation, cervicofacial surgery. Other predisposing factors include male sex, diabetes mellitus, immunosuppression, alcoholism, and malnutrition.
Most patients with osteoporosis receive bisphosphonate therapy. Occurrence of BONJ is associated with duration of bisphosphonate therapy, concomitant use of corticosteroids, and mucosal disruption. The latter may facilitate Actinomyces colonization and invasion of the jaw, as Actinomyces spp. A year-old woman presented with lumpy jaw syndrome following root canal treatment of two right mandibular molar teeth numbers 45 and Tooth 46 was extracted Figure 3A , followed by tooth 45 2 months later Figure 3B as mandibular Actinomycosis due to A.
Overview of Actinomycosis
Members of the genus Actinomyces are gram positive, anaerobic, non-acid-fast rods, many of which are filamentous or branching. Although they are normal flora of the oral and nasopharyngeal membranes, several species are associated with diseases in animals. A bovis is the etiologic agent of lumpy jaw in cattle. It has also been isolated from nodular abscesses in the lungs of cattle and infrequently from infections in sheep, pigs, dogs, and other mammals, including chronic fistulous withers and chronic poll evil in horses. Lumpy jaw is a localized, chronic, progressive, granulomatous abscess that most frequently involves the mandible, the maxillae, or other bony tissues in the head. Disease is seen when A bovis is introduced to underlying soft tissue via penetrating wounds of the oral mucosa from wire or coarse hay or sticks. Involvement of adjacent bone frequently results in facial distortion, loose teeth making chewing difficult , and dyspnea from swelling into the nasal cavity.
Actinomycosis in animals
Actinomycosis is a rare infectious bacterial disease caused by Actinomyces species. In cases of actinomicosis the bacteria do gradually spread through tissue to other parts of the body. Examples of bacteria that cause this type of infection are Actinomyces israelii A. Although humans can be affected, actinomicosis is more likely to affect animals, such as cattle lumpy jaw.
What is actinomicosis? What causes actinomicosis?
Actinomycosis: etiology, clinical features, diagnosis, treatment, and management