Fusobacterium spp. (F. necrophorum and F. nucleatum) are gram-negative anaerobic bacterial microorganisms that normally reside in the human oropharynx as commensal flora [1] [2]. For still unknown reasons, the infection can develop in young and healthy adults (F. necrophorum) and in the elderly population with various risk factors, most important being dialysis of neoplastic disease (F. nucleatum) [2] [3]. Fusobacterium infection is most commonly encountered in the form of Lemièrre's syndrome - initial infection of the oropharynx (angina and/or tonsillitis) is followed by thrombophlebitis of the internal jugular vein and septic dissemination of the bacteria through this venous vessel [1] [2] [3]. Fusobacteria is able to reach the internal jugular vein through the lateral pharyngeal space, triggering the formation of platelet aggregates and an intense inflammatory reaction [4]. Approximately 7 days pass from throat infection to the formation of septic emboli, which travel to the lungs and the larger joints in most cases [2] [4]. Patients complain of a sore throat, pain in the neck, fever, lethargy, and poor general condition [5] [6]. The infection is known to be life-threatening in the absence of early antibiotic therapy [1] [2] [4] [5] [6]. In addition to Lemièrre's syndrome, other infections of the head and neck (mastoiditis, sinusitis, abscess formation, and otitis, commonly seen in in the pediatric population), as well as meningitis are possible manifestations of fusobacterium infection, and organ-related signs and symptoms are noted [1] [5].

• Foul Smelling Discharge

  A foul-smelling discharge is pathognomonic although its absence does not exclude a diagnosis. Several anaerobic culture systems are available. Normal blood agar plates can be used. [virology-online.com]

  Major Clues to Anaerobic Infection Foul-smelling discharge Infection in proximity to a mucosal surface Tissue necrosis, gangrene Gas in tissues or discharges Infection associated with malignancy Infections secondary to human or animal bite Infection related [antimicrobe.org]

• Sputum

  Culture sites were pleural effusions (n 7 out of 1,500; 0.5%), blood cultures (n 11 out of 16, 145; 0.07%), bronchial lavage at bronchoscopy (n 7), ascitic fluid (n 1), sputum (n 1) and groin abscess (n 1). [tandfonline.com]

The diagnosis of fusobacterium infection is difficult to make without a thorough clinical investigation that might lead the physician toward this pathogen as the underlying cause. A detailed patient history is perhaps a pivotal step, as the initial signs and symptoms of a sore throat and subsequent deterioration can be indicative of fusobacterium infection. After a complete physical examination, imaging and microbiological studies should be employed to solidify the diagnosis. Computed tomography (CT) is recommended, as it is able to detect multiple septic emboli and confirm inflammatory lesions in the sinuses, the mastoid processes and in other organs [2] [5]. Conversely, microbiological examination, principally in the form of blood cultures, is advised, but because several weeks are necessary for fusobacterium growth, more advanced methods are necessary [5] [7]. For this reason, polymerase chain reaction (PCR), a procedure that detects bacterial deoxyribonucleic acid (DNA) in patient samples, should be performed whenever possible, as it carries a very good rate of diagnosis in a much faster manner than blood cultures [1] [2] [5] [7]. Its price and the need for advanced laboratory requirement, however, limits the use of this procedure in many parts of the world in daily practice [5] [7]. In spite of the challenges faced in confirming fusobacterium infection, reports have emphasized the perhaps critical role of the physician's awareness of this bacterial microorganism in the differential diagnosis, suggesting that clinical findings seen in these patients must include fusobacterium as a possible cause [5] [6].

• Bilateral Pulmonary Infiltrate

  pulmonary infiltrates or loculated infection in head and neck Positive BC unless therapy with antibiotics 9 TABLE 2. [cmr.asm.org]

• Normal Chest X-Ray

  He was admitted considering the differentials of sepsis-induced acute kidney injury, TTP, and pulmonary-renal syndrome, though his normal white cell count and normal chest X-ray were confusing. [hindawi.com]

• Streptococcus Bovis

  bovis 1         Streptococcus group A 1         Streptococcus group B 1         Streptococcus group C 4 1         Streptococci (oral) 8 5         Total 20 11 TABLE 4. [cmr.asm.org]

1. Creemers-Schild D, Gronthoud F, Spanjaard L, Visser LG, Brouwer CNM, Kuijper EJ. Fusobacterium necrophorum, an emerging pathogen of otogenic and paranasal infections? New Microbes New Infect. 2014;2(3):52-57.
2. Riordan T. Human Infection with Fusobacterium necrophorum (Necrobacillosis), with a Focus on Lemierre’s Syndrome. Clin Microbiol Rev. 2007;20(4):622-659.
3. Afra K, Laupland K, Leal J, Lloyd T, Gregson D. Incidence, risk factors, and outcomes of Fusobacterium species bacteremia. BMC Infect Dis. 2013;13:264
4. Shahani L, Khardori N. Fusobacterium necrophorum – beyond Lemierres syndrome. BMJ Case Reports. 2011;2011:bcr0720114527.
5. Arane K, Goldman RD. Fusobacterium infections in children. Can Fam Physician. 2016;62(10):813-814.
6. Cheung WY, Bellas J. Fusobacterium: Elusive cause of life-threatening septic thromboembolism. Can Fam Physician. 2007;53(9):1451-1453.
7. Aliyu SH, Marriott RK, Curran MD, et al. Real-time PCR investigation into the importance of Fusobacterium necrophorum as a cause of acute pharyngitis in general practice. J Med Microbiol. 2004;53(Pt 10):1029–1035.