Fusobacterium nucleatum causing a pyogenic liver abscess: a rare complication of periodontal disease that occurred during the COVID-19 pandemic.

Fusobacterium nucleatum is a periodontal commensal and pathogen. In rare cases, these anaerobic gram-negative bacilli have been reported to cause pyogenic liver abscesses (PLAs). We describe a patient who developed a periodontal abscess during the COVID-19 pandemic and was unable to access the restricted General Dental Services at this time. She subsequently developed a F. nucleatum bacteraemia and liver abscess. The non-specific signs and symptoms experienced meant the patient self-isolated due to suspected COVID-19 infection and presentation to hospital was delayed. We also include the results of a literature search of other cases of PLAs attributed to F. nucleatum PLAs often develop insidiously. They require percutaneous drainage and prolonged antimicrobial therapy. Clinicians should be aware of this rare complication of a dentoalveolar infection in a patient who is systemically unwell.

Calcitonin negative medullary thyroid cancer in ectopic thyroid tissue: a rare diagnosis in an unusual location.

Medullary thyroid cancer is an aggressive form of thyroid cancer arising from parafollicular C cells. Calcitonin (CT) is a specific and sensitive biochemical marker which typically aids primary diagnosis and disease surveillance following treatment. There are rare cases of calcitonin negative medullary thyroid cancer (CNMTC) documented in the literature; however, to our knowledge, this case is the first report of CNMTC arising in ectopic thyroid tissue. We report a case of a 45-year-old man who attended his primary care physician with painless anterior neck swelling. In the absence of CT secreting disease, we have demonstrated the investigative process and the importance of immunohistochemical analysis to achieve a diagnosis. We also consider the challenges of monitoring disease recurrence in the absence of reliable biochemical markers.

Antibiotic misuse in respiratory tract infections in children and adults-a prospective, multicentre study (TAILORED Treatment).

Respiratory tract infections (RTI) are more commonly caused by viral pathogens in children than in adults. Surprisingly, little is known about antibiotic use in children as compared to adults with RTI. This prospective study aimed to determine antibiotic misuse in children and adults with RTI, using an expert panel reference standard, in order to prioritise the target age population for antibiotic stewardship interventions. We recruited children and adults who presented at the emergency department or were hospitalised with clinical presentation of RTI in The Netherlands and Israel. A panel of three experienced physicians adjudicated a reference standard diagnosis (i.e. bacterial or viral infection) for all the patients using all available clinical and laboratory information, including a 28-day follow-up assessment. The cohort included 284 children and 232 adults with RTI (median age, 1.3 years and 64.5 years, respectively). The proportion of viral infections was larger in children than in adults (209(74%) versus 89(38%), p < 0.001). In case of viral RTI, antibiotics were prescribed (i.e. overuse) less frequently in children than in adults (77/209 (37%) versus 74/89 (83%), p < 0.001). One (1%) child and three (2%) adults with bacterial infection were not treated with antibiotics (i.e. underuse); all were mild cases. This international, prospective study confirms major antibiotic overuse in patients with RTI. Viral infection is more common in children, but antibiotic overuse is more frequent in adults with viral RTI. Together, these findings support the need for effective interventions to decrease antibiotic overuse in RTI patients of all ages.

Th17 development and autoimmune arthritis in the absence of reactive oxygen species.

Dendritic cells (DC) express a functional NADPH oxidase and produce reactive oxygen species (ROS) upon interaction with microbes and T cells. Exposure to ROS leads to DC activation and maturation, as evidenced by phenotypic and functional changes. We have evaluated how endogenous ROS production affects the cytokine secretion pattern and T cell-activating capacity of bone marrow-derived murine DC. DC treated with ROS scavengers, as well as DC from mice that lack a functional NADPH oxidase (and thereby inherently deficient in ROS production) produced significantly increased levels of IL-1beta, IL-6, TNF-alpha and TGF-beta in response to microbial activation. DC deficient in ROS production induced high levels of IFN-gamma and IL-17 in responding T cells after Ag-specific or superantigen-induced activation. Finally, we show that ROS deficiency affected the induction of a T cell-dependent inflammatory condition, collagen-induced arthritis (CIA). C57BL/6 mice that lack a functional NADPH oxidase developed a severe and erosive CD4-dependent CIA, whereas the majority of the congenic wild-type animals remained healthy. These data suggest that ROS act as immunomodulators in DC-driven T cell activation and perhaps also in T cell-dependent immunopathology.