ABSTRACT

Actinomyces are gram positive bacilli which generally colonize in mouth, colon and vagina. The members of genus Actinomyces are facultative anaerobic or microaerophilic organisms and have a branching flamentous structure. They cause classical actinomycosis. Among the Actinomyces species; A. israelii, A. viscosus, A. naeslundii, A. odontolyticus, A. bovis and A. neuii are the mostly isolated organisms from clinical cases. A rarely encountered member of this group, Actinomyces neuii does not show branching and is catalase and CAMP positive and is a coryneform shaped bacillus. Although Actinomyces is mostly found as contaminating organism, in some cases it is reported as a pathogen. Actinomyces neuii has been reported in chorioamnionitis, neonatal sepsis, vertebral osteomyelitis, cervical lymphadenitis, breast abscess, fatal bacteremia and postoperative endophthalmitis. In our case, A. neuii was isolated from a perineal abcess and it was not previously reported. In our case, Actinomyces neuii was identified by commercial identification systems. For this purpose; VITEK MS and VITEK^®2 Compact (both by bioMérieux, France) were used in the clinical microbiology laboratory and then this identification was confirmed as the Actinomyces neuii subsp. neuii by the 16S rRNA sequencing. Also, the positivity of CAMP was demonstrated in the laboratory. As in the cases of other actinomycosis, the treatment of the abcess caused by the Actinomyces neuii is through the surgical debridement. The antimicrobial susceptibility testing is not performed since the organism is reported to be susceptibile to common antibiotics. Beta lactam antibiotics are acknowledged as the proper selection for antibiotic treatment.

Introduction

As member of the oral flora, actinomyces are organically anaerobic or microaerophilic and sporless microorganisms. These bacteria with difteroid basil morphology that do not react to acid-fast stain and do not show motility are gram positive bacteria and show branching (1). A. israelii, A. viscosus, A. naeslundii, A. odontolyticus, A. bovis and A. neuii are species isolated from many clinical cases among Actinomyces species.

Actinomyces neuii is aerobic and catalase positive member of this family. A. neuii was involved in the CDC coryneform group 1 bacteria until 1994. In a study by Funke et al. (2) on the metabolic and cellular fatty acid pattern of bacterium and 16S ribosomal RNA (rRNA) sequence; bacteria were defined as Actinomyces neuii subsp. neuii and Actinomyces neuii subsp. Anitratus.

A. neuii was previously isolated as an infection agent in soft tissue in a study conducted by Gomez-Garces et al. (3). In our study, A.neuii was first isolated from a perineal abscess sample in our country.

Discussion

Actinomyces species have been isolated from clinical specimens such as blood, wound, bone, abscess, bronchial wash, gallbladder fluid, pleural fluid and urine (1).  Although they generally show better reproduction in anaerobic conditions, some species such as A.neuii can be isolated under aerobic conditions and 5-10% CO2 conditions.

A. neuii is catalase and CAMP positive and coryneform-shaped basil. These features separate it from other Actinomyces species. Also, A. neuii has a short basil appearance that does not show branching, unlike other species (2-4). It fermentates glucose, maltose, sucrose, mannitol, lactose, mannose, trehalose and xylose. Negative catalase reaction of A. neuii has also been reported. Brunner et al. (5) defined catalase negative A. neuii in a patient with breast prosthesis infection.

Actinomyces neuii, isolated from scrotal abscess sample, is a very rare microorganism seen in the laboratory as an infection agent and was not reported as agent in our country before. This case was presented because A. neuii is a clinically important and rare microorganism. In the literature, it was reported as pathogenic microorganism in different clinical specimens. For example, Mann et al. (6) isolated A. neuii as agent in a patient with neonatal sepsis and chorioamnionitis. In various studies, A. neuii was reported to cause endoftalmit, bacteremia, endocarditis, pericarditis, osteomyelitis and prostatitis (7,8). Lacoste et al. (9) isolated A.neuii in breast abscess.

Surgical debridement is recommended in the treatment of soft tissue infections caused by Actinomyces species. It is sensitive to many antibiotics and β-lactam antibiotics is primarily preferred (10).

A.neuii, isolated from perineal abscess as a pathogen agent, which was a rarely seen agent, was reported here. It is important for the prognosis to determine the appropriate treatment approach with the correct identification of species with new microbiological methods. Isolation of A.neuii for the first time in our country adds specificity to the study.