Perianal Actinomycosis: A Surgeon's Perspective and Review of Literature

Abstract

Actinomycosis is a serious suppurative, bacterial infection caused by the gram-positive anaerobic Actinomyces species. Primary perianal actinomycosis is rare and challenging for the colorectal surgeon. We aimed to present our experience and compare this with available literature. All patients with isolated Actinomyces on microbiology reports, between January 2013 and February 2021, were identified and reviewed. Data collection was retrospective based on electronic patient records. The site of infection and treatment strategy were examined. Perianal cases were evaluated in depth. All publications available in the literature were interrogated. Fifty-nine cases of positive actinomycosis cultures were reviewed. Six cases of colonization were excluded. Actinomyces turicensis was the most common organism isolated. Five cases of perianal actinomycosis were identified requiring prolonged antibiotic and surgical therapy. Twenty-one studies, most case reports, published since 1951 were also reviewed. Diagnosis of perianal actinomycosis may be challenging but should be suspected particularly in recurrent cases. Prolonged bacterial cultures in anaerobic conditions are necessary to identify the bacterium. An extended course of antibiotic therapy (months) is required for eradication in certain cases.

Keywords: Abscess; Actinomycosis; Anal canal; Fistula.

Fig. 1.

Magnetic resonance imaging of pelvis STIR sequence with contrast of the 65-year-old male with perianal actinomycosis. At 12:00, there is an intersphincteric and extrasphincteric 8 mm fluid collection which continues with a small tract to the right side of the buttock up to the subcutaneous surface around 8 o’clock.

Fig. 2.

Magnetic resonance imaging of pelvis STIR sequence with contrast of the 49-year-old male. There is a small collection with a thick enhancing wall at the base of the left scrotum extending posteriorly to the left perineum. The collection measures 2.0 × 0.7 × 2.1 cm. No fistula or communication with the anus.