Indian Journal of Pathology and Microbiology

: 2009  |  Volume : 52  |  Issue : 1  |  Page : 120--121

Empyema thoracis due to actinomyces odontolyticus

DR Mohan1, Beena Antony1, GM Shivakumarappa2,  
1 Department of Microbiology, Sri Siddhartha Medical College, Tumkur, India
2 Department of Surgery, Sri Siddhartha Medical College, Tumkur, India

Correspondence Address:
Beena Antony
Department of Microbiology, Fr. Muller Medical College, Kankanady, Mangalore, Karnataka - 575 002


Actinomyces odontolyticus has been reported as an opportunistic pathogen causing systemic infections. A case of empyema thoracis due to this organism in a 68-year-old male is reported here. The patient did not have any underlying disease or immunosuppression. The organism was isolated from his oral flora also. Eight cases of thoracopulmonary infections due to A. odontolyticus have been reported from the western countries, but none from India.

How to cite this article:
Mohan D R, Antony B, Shivakumarappa G M. Empyema thoracis due to actinomyces odontolyticus.Indian J Pathol Microbiol 2009;52:120-121

How to cite this URL:
Mohan D R, Antony B, Shivakumarappa G M. Empyema thoracis due to actinomyces odontolyticus. Indian J Pathol Microbiol [serial online] 2009 [cited 2021 Sep 26 ];52:120-121
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Actinomyces are a group of gram positive bacilli, predominantly anaerobic in nature. They frequently colonize the oral cavity and cause cervicofacial disease. [1] The most significant pathogen of this group is A. israelii which is associated with the cervicofacial and thoracopulmonary diseases. [2] However, A. odontolyticus , a less commonly recognized pathogen of the Actinomyces group, has been encountered in systemic infections such as peritonitis, brain abscess and thoracopulmonary. [3],[4],[5] We present here a case of empyema thoracis caused by A. odontolyticus in an elderly person who did not have any underlying disease or immunosuppression.

 Case Report

A 68-year-old male with the history of intermittent fever, chest pain while lying on left lateral position, breathlessness and productive cough with brownish sputum was admitted to the Department of Medicine of a Tertiary care centre, Tumkur. On examination, he showed signs of pleural effusion and consolidation on the right side. Radiological investigation confirmed the finding of massive pleural effusion. The patient was a chronic smoker and an occasional alcoholic in the past. His oral hygiene was very poor. There was no history of diabetes or hypertension. The case was referred to the Department of Surgery and intercostal drainage was done. Two liters of fluid was drained and the draining tube was left in situ. Five ml of the fluid was sent to the department of Microbiology without delay with aseptic precautions for microbiological investigations. A presumptive diagnosis of tuberculosis was made and the patient was given an empirical treatment of antitubercular drugs, cefotaxime and bronchodialators.

Direct microscopy of the fluid did not show any acid fast bacilli, but gram stain revealed few gram positive filamentous bacteria. The sample was subjected for culture of aerobes, anaerobes and capnoic organisms on appropriate media like blood agar, MacConkey's agar, neomycin blood agar and Robertson's Cooked Meat medium. Anaerobic condition was achieved by incubating in a Dynox jar at 37C for 48 h. No aerobic or capnoic bacteria grew in culture. However, media-incubated anaerobically yielded pure growth of smooth, tiny colonies on 48 h which developed reddish brown pigmentation by 7 days of incubation. They were sensitive to metronidazole and appeared as slender gram positive bacilli on gram staining. The organism was presumptively identified as A. odontolyticus . Biochemically, it fermented glucose, hydrolysed aesculin and reduced nitrate. It did not produce catalase and did not ferment raffinose and trehalose, thereby confirming the identification. [1],[2] Antibiogram revealed sensitivity to metronidazole, minocycline, cefatoxime, amoxicillin-clavulanic acid, clarithromycin and chloramphenicol. A subsequent sample obtained two days later also yielded the same organism.

Meanwhile, the sample taken from the oral cavity grew a mixed flora containing gram positive cocci, gram positive bacilli and gram negative bacilli. Few colonies of A. odontolyticus were grown along with non-hemolytic Streptococci and Porphyromonas species in culture. Based on the gram stain and culture reports, the treatment regimen was changed to cefotaxime and metronidazole, the drug of choice for anaerobes. The patient showed signs of improvement by the first week; chest pain resolved and he recovered completely by the third week.


A. odontolyticus is an anaerobic and capnoic gram positive bacilli that appear as thin filaments with or without branching. A very characteristic feature of this organism is the production of red colonies on blood agar. Like other members of Actinomyces, this organism also occurs as a part of indigenous oral flora in humans. A. odontolyticus was found to be a component of oral flora in this patient. Poor oral hygiene of the patient coupled with old age would have been predisposed to the infection in this case.

A. odontolyticus has been regularly isolated from dental caries and reported as an opportunistic pathogen associated with cervicofacial, abdominal and thoracic diseases as implied in the literature. Only 8 cases of thoracopulmonary infections due to A. odontolyticus were reported from the western countries. [6],[7] To the best of our knowledge, the present case report is the first report on pulmonary infection due to A. odontolyticus from India. A recent study from Pune reported Actinomycotic bacteremia after dental procedures as 30%, the most common species being A. viscosus and A. odontolyticus . [8]

Many reported cases of A. odontolyticus infections and studies conducted in experimental animals have pointed out a synergistic role of this organism with other members of oral flora in the pathogenesis of thoracopulmonary infections. [9] However, in our case, A. odontolyticus was the sole organism isolated.

All the cases reported earlier had some association with periodontal disease, immunosuppression or underlying lung disease of a longer duration. [4],[6],[10] The patient in this case did not have any of these predisposing factors, except poor oral hygiene. As reported by Dontfraid and Ramphal, [4] this case also mimicked tuberculosis. As the illness would have been in the beginning stage, it could be treated without much complication.

With the advent of molecular research, anaerobiosis and the related fields of interest were completely forgotten. However, the earlier reports and the present case study point out the significant role of normal anaerobic oral flora in causing serious infections and hence the need to include anaerobic culture techniques routinely.


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