Fusobacterium necrophorum from sore throats and healthy controls

Abstract number: P1611

Jensen A., Sørensen B., Hagelskjær Kristensen L., Prag J.

Background and Objectives: Recently several publications have shown an association between clinical tonsillitis and Fusobacterium necrophorum. The objective of the study was to identify F. necrophorum by culture and Real-time PCR in throat swabs from patients with pharyngotonsillitis and healthy controls.

Methods: The isolation rate in 50 healthy military recruits aged 18 to 24 were compared with the rate in 70 randomly picked patients aged 16 to 30 years old from general practitioners with sore throats by using a selective anaerobic agar plate with, 5.0 mg/l nalidixic acid and 2.5 mg/l vancomycin and analysed by a species specific real-time PCR assay. All 1643 swabs sent to our laboratory in 2006 were examined for the presence of F. necrophorum using the same selective plate.

Results:F. necrophorum was found in 7 healthy controls and in 16 patients, p > 0.05, by culture and by PCR in 14 controls and 35, p = 0.03. The mean Ct-value of PCR positive samples were significantly lower, p = 0.02, in patients, 27 cycles compared to 31 cycles in controls.

During 12 month F. necrophorum was isolated from 146 throat swabs, giving an isolation rate of 9%. The highest isolation rate, 20%, was found in the patients aged 16 to 20 years, while only a few were found in children less than 10 years old and in adults older than 40 years old (<5%). A tendency towards a greater, but non-significant isolation rate in males were 10.4% compared to 7.9% for females, p = 0.08). No variation in the isolation rate was observed through the year. There was a positive significant correlation between the isolation of F. necrophorum and the isolation of Group C streptococci (p < 0.0001). Contrary, the rate was significant lower when Group A streptococci was present (p < 0.001).

Conclusion:F. necrophorum is frequently a part of the normal throat flora. However this study also shows that larger quantities of F. necrophorum may cause tonsillitis, particularly in adolescents. However, as F. necrophorum can be present as normal throat flora the clinical symptoms have to be considered when considering F. necrophorum as the cause of tonsillitis. In addition, there seems to be an unexplained synergetic relationship between F. necrophorum and Group C streptococci.

We suggest that throat swabs from patients with a sore throat old negative in strep-A test should be examined anaerobically for the presence of F. necrophorum, particularly in patients 10 to 40 years old. Further studies are needed.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Location: Barcelona, Spain
Presentation type:
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