DEPARTMENT OF PATHOLOGY
The Johns Hopkins Medical Institutions

Vol. 15 No. 36

MICROBIOLOGY NEWSLETTER

Monday, September 16, 1996


A. Provided by Carmela Groves, R.N., M.S., Chief, Division of Outbreak Investigation, Maryland Department of Health and Mental Hygiene

No report.

B. The Johns Hopkins Hospital (Information provided by Dr. Beth Allen, Pathology Resident).

Patient Clinical Information: The patient is a 31 year old female with no significant past medical history who presented to the Emergency Department at Johns Hopkins Hospital with complaints of neck edema, erythema and swelling beginning three days ago. The symptoms had gotten progressively worse and she now had complaints of dysphagia. Physical examination was remarkable for an erythematous, fluctuant, and tender area over the right anterior neck. Tenderness and fluctuation were revealed on palpation of the floor of the mouth as well. A CT scan showed a 4 x 3 x 3 cm phlegmon of the right anterior neck extending from the angle of the mandible to the lateral pharyngeal space. The patient was admitted for incision and drainage of the neck abscess as well as removal of an infected tooth. A large amount of purulent material was aspirated from the area and sent for culture. Bacterial cultures grew out the organism Rothia dentocariosa.

Organism: Rothia dentocariosa is the prototypic organsim of the genus Rothia. The organism was first described in 1967. The organisms resemble Nocardia and Actinomyces species but differ from these in their cell wall constituents and physiology (Pape, 1979). The organism is an aerobic or facultatively anaerobic, non-endospore forming, non-motile, pleomorphic, Gram positive coccobacillus that can form filamentous branches. Rod-shaped forms are produced with growth on agar and more spheroidal forms are found with growth in broth.

Disease: Rothia dentocariosa is part of the normal flora of the oral cavity. The pathogenicity of the organism was first demonstrated experimentally in 1969 using mice. When this organism causes disease, it is usually associated with dental caries and periodontal disease. Rothia dentocariosa has been implicated in a number of other disease states including a periappendiceal abscess, pilonidal abscess and infectious endocarditis. One case of infectious endocarditis with a complicating perivalvular abscess has been reported as well as one case reported with a complicating brain abscess (Isaacson, 1988). Pneumonia resulting from R. dentocariosa has been observed in immunocompromised individuals (Schiff, 1987). In most of the cases of endocarditis and pneumonia, periodontal disease was identifed in the patients.

Identification: Identification requires growth of the organism on culture media. Growth is slow in aerobic and microaerophilic conditions and usually requires 5-7 days of incubation. The colonies are off-white in color and may be rough or smooth. Gram stain reveals Gram positive pleomorphic rods with branching and diptheroid forms. The organism is a mannitol and lactose non-fermenter. R. dentocariosa is catalase positive which aids in differentiating it from two other organisms found in the normal flora: Lactobacillus and Bifidobacterium.

Treatment: R. dentocariosa is usually sensitive to several antibiotics including aminoglycosides, tetracycline, vancomycin, pencillin, erythromycin, ceftriaxone and cefazolin. Pencillin is the recommended antibiotic of choice for infection.

References:

Barksdale L. Identifying Rothia dentocariosa. Ann Int Med, 1979;91:786-8.

Koneman EW(ed), et al. Color Atlas and Textbook of Diagnostic Microbiology, 4th edition; pp. 498-9.

Pape J, et al. Infective Endocarditis Caused by Rothia dentocariosa. Ann Int Med, 1979;91:746-8.

Schiff MJ, et al. Rothia dentocariosa Pneumonia in an Immunocompromised Patient. Lung, 1987; 165:279-82.

Sudduth EJ, et al. Rothia dentocariosa Endocarditis Complicated by Perivalvular Abscess. Clin ID, 1993;17:772-5.

Isaacson JH, et al. Rothia dentocariosa Endocarditis Complicated by Brain Abscess. Ann J Med 1988;84:352-4.

Announcements: Joint ID and MMI Seminar Series held at noon on Thursdays - 2030 Hygiene

9/18/96 "Effect of M. tuberculosis on HIV replication" - Delia Goletti, MD, PhD, Laboratory of Immunoregulation, Visiting Associate, NIH-NIAID

9/25/96 "Molecular anatomy of stringent regulation in Escherichia coli" - Dipankar Chatterji, PhD, Ctr Cellular and Molecular Biology, Professor, Hyderabad, India

10/03/96 "Colpain is the target antigen of a Th1 clone that transfers protective immunity against Schistosoma mansoni" - Dragana Jankovic, PhD, Laboratory of Parasitic Diseases, Visiting Scientist, NIH-NIAID

10/10/96 "The impact of HIV viral load on perinatal transmission and progression of disease in infants" - Thomas C. Quinn, MD, Professor of Medicine, JHU


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