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Year : 2019  |  Volume : 62  |  Issue : 2  |  Page : 326-328
Actinomyces naeslundii causing pulmonary endobronchial Actinomycosis – A case report

1 Department of Microbiology, St. John's National Academy of Health Sciences, Koramangala, Bangalore, Karnataka, India
2 Department of Pulmonary Medicine, St. John's National Academy of Health Sciences, Koramangala, Bangalore, Karnataka, India

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Date of Web Publication10-Apr-2019


Actinomyces naeslundii is a commensal flora of the oral cavity and is generally considered as an avirulent saprophytic bacterium in immunocompetent patients. It can become an opportunistic anaerobic pathogen in oral cavity in patients with poor oral hygiene or tooth extraction and can cause periodontal disease. Pulmonary Actinomycosis is a rare manifestation and may be suspected in middle-aged male patients with cough and hemoptysis showing radiological findings of a peripheral mass or chronic consolidation in whom repeated aerobic cultures have yielded negative results. Here, we report isolation of A. naeslundii from the bronchoalveolar lavage sample from an immunocompetent patient who presented with chronic nonresolving pneumonia of 6 months duration.

Keywords: Actinomycosis, filamentous rods, malignancy, relapsing infection

How to cite this article:
Supriya B G, Harisree S, Savio J, Ramachandran P. Actinomyces naeslundii causing pulmonary endobronchial Actinomycosis – A case report. Indian J Pathol Microbiol 2019;62:326-8

How to cite this URL:
Supriya B G, Harisree S, Savio J, Ramachandran P. Actinomyces naeslundii causing pulmonary endobronchial Actinomycosis – A case report. Indian J Pathol Microbiol [serial online] 2019 [cited 2022 Jul 1];62:326-8. Available from: https://www.ijpmonline.org/text.asp?2019/62/2/326/255840

   Introduction Top

Actinomycosis is a chronic granulomatous disease caused by Gram-positive filamentous asporogenous anaerobic or microaerophilic bacteria that are included in the family Actinomycetaceae, genus Actinomyces.[1] They are normal commensal of the oral cavity, colon, and vagina. Despite its low virulence, it can become pathogenic in certain predisposing conditions. The pulmonary form of Actinomycosis constitutes only 15% of the total burden of disease caused by Actinomyces species. It is thought to be caused primarily by the inhalation or aspiration of oropharyngeal or upper gastrointestinal secretions and rarely by local spread from cervicofacial region or through hematogenous spread from distant sites.[3] Three important clinical features that make one consider this as a causative agent include chronicity of the disease which can mimic malignancy, development of a sinus tract which may spontaneously resolve and recur, and a refractory or relapsing infection after a short course of chemotherapy. Actinomycosis remains a diagnostic challenge even today in this era of technological advances.

   Case History Top

A 56-year-old female patient presented to the Department of Pulmonary Medicine of our hospital with primary complaints of dry cough and right-sided chest pain for the past 6 months and low grade fever in the past few weeks. Pain was aggravated with deep breath, which was nonradiating and localized to right infrascapular region. There was no history of hemoptysis. The patient also complained of loss of weight, appetite, and puffiness of face. She is not a known diabetic. Past medical history was noncontributory. She was evaluated extensively at a local health-care facility during the initial phase of her illness. It included computerized tomography (CT) scan of chest that revealed lower lobe consolidation in right lung. Histopathological examination (HPE) of the biopsy of the lesion was suggestive of suppurative inflammation and she was treated with antibiotics; the details of which were not available. These symptoms persisted and progressively worsened over the past 6 months.

On examination, her vitals were within normal limits. Pallor, clubbing, and mild pedal edema were observed on general physical examination. Chest auscultation showed right infrascapular crackles. Lymph nodes were not enlarged and other systemic examination findings were noncontributory.

Radiological investigation was carried out at our institution. Right lung opacity was observed on plain chest X-ray. Thoracic high-resolution CT scan revealed right upper lobe consolidation, which the radiologists opined as probably of infective origin or a neoplastic lesion. On bronchoscopic examination, a whitish nodule in the right lower lobe, resembling a foreign body, was observed. The lesion was excised and the tissue sample was sent for HPE. Additionally, Properly collected bronchoalveolar lavage (BAL) sample was subjected for microbiological investigations.

Gram-positive, thin, branching filaments along with inflammatory cells suggestive of Nocardia or Actinomycetes were observed on Gram's stain [Figure 1]a. Nocardia was ruled out based on Kinyoun's stain. Aerobic culture on 5% sheep blood agar and Sabouraud Dextrose Agar did not yield any growth on even extended period of incubation. Brain-heart infusion blood agar and Robertson's cooked meat broth were included for anaerobic culture. A pure growth of white, rough, dry pinpoint colonies were observed on the agar plate after 7 days of incubation. On further incubation, the colonies had an irregular surface [Figure 1]b. Further identification was done by using Gram's stain [Figure 1]c and biochemical tests. The isolate was Gram-positive with thin branching filaments, nonacid fast [Figure 1]d, catalase, and oxidase negative. It was identified as Actinomyces naeslundii by the automated VITEK-2 system using the ANC card.
Figure 1: (a) Gram's stain of BAL sample showing numerous pus cells with filamentous branching Gram-positive bacteria (1000×). (b) Culture showing white dry pinpoint colonies with irregular surface. (c) Gram's stain from the colonies showing filamentous branching Gram-positive bacteria (1000×). (d) Modified Ziehl–Neelsen staining from colony showing nonacid fast branching filaments

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HPE of the endobronchial biopsy sample revealed colonies of filamentous microorganisms surrounded by a few inflammatory cells suggestive of Actinomyces [Figure 2]a and Gomori Methenamine Silver (GMS) stains [Figure 2]b. No tumor cells were observed.
Figure 2: (a) Histopathological examination of the endobronchial biopsy sample revealed colonies of filamentous microorganisms surrounded by a few inflammatory cells (400×). (b) Gomori Methenamine Silver staining (GMS) showing silver impregnated filamentous bacteria against golden background (400×)

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   Discussion Top

Genus Actinomyces includes a group of anaerobic Gram-positive bacilli, some of which are normal flora of the oral cavity and coexist with other commensal bacteria. Disruption of mucosal barrier is essential for the development of Actinomycosis, which allows the bacteria to invade and produce the disease.[4] The important risk factors for the development of pulmonary Actinomycosis include poor oropharyngeal hygiene, preexisting dental disease, and alcoholism. Other less associated factors include chronic lung disorders such as chronic obstructive lung disease, chronic mycobacterial disease, bronchiectasis, and aspergilloma. Damaged lung tissue creates an anaerobic milieu, which favors the growth of Actinomyces species.[3]

Among the Actinomyces species, Actinomyces israelli is recognized as the major etiological agent of Actinomycosis, followed by A. naeslundii.[1] Actinomyces meyeri can also cause pulmonary infections and has shown a tendency for hematogenous dissemination.[4] Generally, actinomycotic infections are characterized by the presence of pale granules except A. naeslundii which does not form granules.[5] The clinical forms of Actinomycosis involve cervicofacial, thoracic, abdominal, and pelvic regions. Pulmonary Actinomycosis is the third most common type of Actinomycosis, which results from aspiration of oropharyngeal or gastrointestinal secretions into the respiratory tract. Though some studies have shown a bimodal age distribution of this condition with an earlier peak in 11–20 age group, most series describe a peak incidence in the fourth and fifth decades of life.[4] During the early stage of the disease, a pulmonary nodule is formed, often not associated with symptoms. This could secondarily lead to constitution of a peripheral mass, with or without cavitation, which could invade adjacent tissue causing fibrotic lesion with slow contiguous growth mimicking a mass, which is often confused with malignancy.[6]

As per Mabeza et al., pulmonary Actinomycosis may masquerade like a submucosal tumor with irregular granular thickening and partial occlusion of bronchi.[7] Similar findings were seen in our case in which lung tissue biopsy showed only dense inflammatory infiltrate, but BAL sample yielded A. naeslundii by anaerobic culture. The method of obtaining a bronchial sample is also very important. Ordinary BAL culture, which if not obtained routinely under anaerobic conditions, will give false-negative results if exposed to air for more than 20 min.[7]

Treatment of pulmonary Actinomycosis is recommended by using beta-lactam antibiotics such as penicillin G, cephalosporins, or amoxicillin for prolonged periods in high doses. Penicillin G is administered intravenously at a dose of 18–24 million units/day over 2–6 weeks, followed by oral therapy with penicillin V or amoxicillin for 6–12 months.[8],[9] Exclusive medical management of less than 3 months duration may be associated with complications during follow-up.[10] Complicated pulmonary Actinomycosis may require surgical intervention to remove severely damaged segments of the lung.[10],[11] Specific preventive measures, such as reduction of alcohol abuse and dental hygiene, may limit the occurrence of Actinomycosis.

In our case, the patient was symptomatic for almost 6 months and the initial CT revealed a pulmonary consolidation and the HPE of the biopsy showed nonspecific suppurative inflammation. On admission to our institution under the division of pulmonary medicine, she was evaluated extensively with a preliminary diagnosis of nonresolving pneumonia based on clinical and CT scan findings. The preliminary microscopic finding on GMS and Kinyoun's staining of the BAL sample helped in the critical decision of including anaerobic culture for the sample. This therefore emphasizes the need for careful examination of preliminary microscopic features. In this case, anaerobic culture results of the BAL sample and histopathology findings were conclusive and helped in arriving at early diagnosis. The patient was treated with augmentin and was asked to come back on follow-up on outpatient basis, but we lost the patient for follow-up.

Pulmonary endobronchial Actinomycosis, though a rare condition, should still be considered in the differential diagnosis of patients with chronic nonresolving pneumonia. This includes tuberculosis, bacterial, or fungal necrotizing pneumonia and small cell carcinoma of lung. It requires a team effort of pulmonologist, radiologist, histopathologist, and a microbiologist for making a diagnosis. Previous literature search on Indian data pulmonary Actinomycosis has been summarized and listed in [Table 1].
Table 1: Indian published data on pulmonary infections caused by Antinomyces spp.

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Anaerobic cultures though not routinely done for respiratory samples such as BAL but attempts must be made especially when the direct microscopic finding is suggestive of an anaerobic infection.

So to conclude, our case report reiterates the importance of prompt and early diagnosis of actinomycotic infections, which thereby facilitates prompt therapy and better prognosis for the patient.


We would like to thank Department of Histopathology, St. John's Medical College, Bangalore.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Fatemeh Norouzi, Maneli Aminshahidi, Behzad Heidari SF. Bacteremia due to Actinomyces naeslundii. Jundishapur J Microbiol 2013;6:306-8.  Back to cited text no. 1
Farrokh D, Rezaitalab F. Bakhshoudeh B. Pulmonary actinomycosis with endobronchial involvement: A case report and literature review. Tanaffos 2014;13:52-6.  Back to cited text no. 2
Katsenos S, Galinos I, Styliara P, Galanopoulou N, Psathakis K. Case Report Primary Bronchopulmonary Actinomycosis Masquerading as Lung Cancer: Apropos of Two Cases and Literature Review; 2015.  Back to cited text no. 3
Jung HW, Cho CR, Ryoo JY, Lee HK, Ha SY, Choi JH, et al. Case report actinomyces meyeri empyema: A case report and review of the literature. Case Rep Infect Dis 2015. doi: 10.1155/2015/291838.  Back to cited text no. 4
Coleman RM, Georg LK, Rozzell AR. Actinomyces naeslundii as an agent of human actinomycosis. Am Soc Microbiol 1969;18:420-6.  Back to cited text no. 5
Marie I, Lahaxe L, Levesque H, Heliot P. Pulmonary actinomycosis in a patient with diffuse systemic sclerosis treated with infliximab. Int J Med 2008;101:419-21.  Back to cited text no. 6
Mabeza GF, Macfarlane J. series “Unusual pulmonary infections” Pulmonary actinomycosis. Eur Respir J 2003:545-51.  Back to cited text no. 7
Kolditz M, Bickhardt J, Matthiessen W. Medical management of pulmonary actinomycosis: data from 49 consecutive cases Transparency declarations. J Antimicrob Chemother 2009;63:839-41.  Back to cited text no. 8
Bennett J, Dolin R, Blaser M. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. Principles and Practice of Infectious Diseases. 8th ed. Philadelphia: Saunders; 2015. p. 2871-2.  Back to cited text no. 9
Valour F, Sénéchal A, Dupieux C, Karsenty J, Lustig S, Breton P, et al. Actinomycosis: Etiology, clinical features, diagnosis, treatment, and management. Infect Drug Resist 2014;7:183-97.  Back to cited text no. 10
Kim SR, Jung LY, Oh I, Kim Y, Shin K, Lee MK, et al. Pulmonary actinomycosis during the first decade of 21st century: cases of 94 patients. BMC Infect Dis 2013;13:216.  Back to cited text no. 11

Correspondence Address:
S Harisree
Department of Microbiology, St. John's Medical College, Koramangala, Bangalore - 34, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJPM.IJPM_706_17

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  [Figure 1], [Figure 2]

  [Table 1]

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