Vol. 16, No. 44
THE JOHNS HOPKINS MICROBIOLOGY NEWSLETTER
Monday, December 15, 1997
A. Provided by Carmela Groves, R.N., M.S., Chief, Division of Outbreak Investigation, Maryland Department of Health and Mental Hygiene
16 outbreaks were reported between December 5 and December 12, 1997.
9 outbreaks of foodborne gastroenteritis associated with food service facilities
7 outbreaks of gastroenteritis associated with long term care facilities (6) and a school (1)
B. The Johns Hopkins Hospital: Information provided by Dr. Rennae Green, Department of Pathology
Case Presentation: A 15 year old, previously healthy, white female presents with a 8 day history of sore throat, fever, headache, and a nonproductive cough. A diagnosis of pharyngitis was made by her private physician and a monospot was negative. Several days later she was admitted with rigors, a temperature of 38.1C, and dehydration. Blood cultures were obtained and she was placed on ceftriaxone and intravenous fluid. After two days she was discharged on oral antibiotics.
After discharge she continued to have daily fevers and her admission blood cultures were reported as positive for gram-negative bacilli in the anaerobic bottle. She returned to clinic and was found to have bilateral basilar infiltrates and pleural effusions on chest radiograph. Contrast-enhanced computed tomography scan of neck and chest showed a small deep vein thrombosis at the level of the pyriform sinus with extension into the right internal jugular vein. Additionally there were small cavitary lung lesions bilaterally and pleural effusions. Initial blood cultures were finalized as Fusobacterium necrophorum. which was sensitive to penicillin. She was treated with intravenous antibiotics for a total course of 6 weeks after which she was completely asymptomatic.
Fusobacterium: Fusobacterium are gram-negative, filamentous, obligate anaerobic bacilli from the family Bacteroidaceae. Other members of this family include Bacteroides and Provetella and the Fusobacterium are distinguished from these other genera by its production of butyric acid without isobutyric acid or isovaleric acids.
Clinical manifestation: Sepsis following pharyngitis (postanginal sepsis) was first described at the beginning of the century, however it was not until 1936 when the distinctive syndrome of postanginal sepsis and internal jugular vein septic thrombophlebitis was characterized by Lemierre. Lemierre described previously healthy adolescents/ young adults who developed septicemia several days after tonsillar or peritonsillar infection. The first symptom was usually sore throat followed by a notable rise of temperature and persistent rigors. Patients then went on to develop painful lymph node and neck soft tissue swelling. They progressed to have distant metastatic abscesses from septic embolization, frequently in the lungs and pleura. Rapid progression with fatal outcome occured within days to weeks without appropriate diagnosis and treatment. The most common organism recovered was Bacillus fundiliformis (later called Fusobacterium necrophorum).
Infection with this organism exhibits a bimodal age distribution with a second peak in the elderly of predominantly pleuropulmonary symptoms due to aspiration events. Fusobacteria are implicated in 1% of all cases of postangingal sepsis and 11% of cases of anaerobic sepsis in adults. In children they account for 3% of anaerobic bacteremias and 5-10% of all anaerobic infections. In the head and neck they are causally associated with 46% of anaerobic infections and 28.5% of complicated sinusitis. Fusobacteria are also seen in 40% of anaerobic bone and joint infections. Other sites of infection include CNS abscess formation, peritonitis and hepatic abscesses, septic abortions and chorioamnionitis.
Pathogenesis: Fusobacteria are normal flora of the oral cavity, GI, and female genital tracts. After proliferation in these primary sites they can then go on to blood stream infection and give rise to septic emboli. These organisms are often isolated in combination with other anaerobes and aerobes from polymicrobial infections. Host factors which appear to be significant in pathogenesis include disruption of mucosal barriers by surgical or trauma related tissue injury and impaired blood supply leading to devitalized tissue.
These lesions tend to arise in the nasopharynx, especially tonsillar and peritonsillar abscesses, similar lesions of the mouth and jaws, in connections with otitis media or mastoiditis, from purulent endometritis following parturition, from appendicitis, and infections of the urinary tract.
Treatment: Appropriate management of fusobacterial infections include prolonged high-dose antibiotics, drainage of abscesses, debridement of devitalized tissue, and the possible use of heparin. Fusobacterium nucleatum, F. mortiferum, and F. varium have been shown to produce beta lactamase which confers penicillin resistance. In some studies heparin appears to shorten the course of illness and help avoid the need for surgery. Based on the cumulative experience in the gynecologic literature, treatment with heparin in cases of septic thrombophlebitis shows a high rate of success.
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