Staphylococcus aureus Keratinocyte Invasion Is Dependent upon Multiple High-Affinity Fibronectin-Binding Repeats within FnBPA

Staphylococcus aureus is a commensal organism and a frequent cause of skin and soft tissue infections, which can progress to serious invasive disease. This bacterium uses its fibronectin binding proteins (FnBPs) to invade host cells and it has been hypothesised that this provides a protected niche from host antimicrobial defences, allows access to deeper tissues and provides a reservoir for persistent or recurring infections. FnBPs contain multiple tandem fibronectin-binding repeats (FnBRs) which bind fibronectin with varying affinity but it is unclear what selects for this configuration. Since both colonisation and skin infection are dependent upon the interaction of S. aureus with keratinocytes we hypothesised that this might select for FnBP function and thus composition of the FnBR region. Initial experiments revealed that S. aureus attachment to keratinocytes is rapid but does not require FnBRs. By contrast, invasion of keratinocytes was dependent upon the FnBR region and occurred via similar cellular processes to those described for endothelial cells. Despite this, keratinocyte invasion was relatively inefficient and appeared to include a lag phase, most likely due to very weak expression of α5β1 integrins. Molecular dissection of the role of the FnBR region revealed that efficient invasion of keratinocytes was dependent on the presence of at least three high-affinity (but not low-affinity) FnBRs. Over-expression of a single high-affinity or three low-affinity repeats promoted invasion but not to the same levels as S. aureus expressing an FnBPA variant containing three high-affinity repeats. In summary, invasion of keratinocytes by S. aureus requires multiple high-affinity FnBRs within FnBPA, and given the importance of the interaction between these cell types and S. aureus for both colonisation and infection, may have provided the selective pressure for the multiple binding repeats within FnBPA

Gastric choristoma of the midline neck in a newborn: a case report and review of the literature.

The current report describes a 3-week-old boy presenting with a gastric choristoma of the anterior compartment of the neck. Initial examination at birth found 3 masses in the anterior region of the neck. The only remarkable symptom consisted of episodes of cyanosis induced by neck flexion. The neck mass was removed after computed tomography scan assessment. Pathology finding showed the diagnosis of gastric choristoma. Cervical location of a gastric choristoma in children is rare. Its presentation as a clinically palpable anterior compartment cervical mass at birth even more rare

Obstructive sleep apnea syndrome after reconstructive laryngectomy for glottic carcinoma.

Obstructive sleep apnea syndrome (OSAS) is characterized by repetitive episodes of partial or complete obstruction of the upper airway during sleep. The obstruction predominantly occurs along the pharyngeal airway but other sites of obstruction have occasionally been described. We report our experience with three patients suffering from OSAS suspected to be of laryngeal origin. OSAS developed after reconstructive laryngectomy for glottic carcinoma and upper airway obstruction seemed to be located in the reconstructed laryngeal area. The three patients were given nCPAP (nasal-continuous positive airway pressure) treatment associated with peroral endoscopic CO2 laser vaporization of the laryngeal edema. After CO2 laser treatment, one patient was able to stop nCPAP treatment. The other two have remained on nCPAP therapy. OSAS may arise in the post-operative period of reconstructive laryngectomy for glottic carcinoma and can be managed by CO2 laser vaporization (laryngeal edema in the reconstructed area) in association with nCPAP treatment