Unusual presence of the immune evasion gene cluster in livestock-associated MRSA of lineage CC398 causing peridural and psoas abscesses in a poultry farmer / Hallazgo inusual de los genes del sistema de evasión inmune en SARM-CC398, asociado a animales, causante de absceso epidural y de psoas en un granjero avícola

Objective: To characterize a methicillin-resistant Staphylococcus aureus (MRSA) isolate responsible for an aggressive infection (peridural and psoas abscess secondary to haematogenous septic arthritis) in a poultry farmer. Methods: Molecular characterization was performed, including spa- and multilocus sequence typing of the isolate, assessment of its resistance phenotype and detection of tetracycline resistance and of virulence and immune evasion cluster (IEC) genes were performed. Results: The MRSA isolate was tetracycline- and fluorquinolone-resistant, and was ascribed to CC398, spa-t1451. The isolate harboured tet(M) (distinctive of livestock-associated (LA) MRSA-CC398 clade) and IEC-type B system (characteristic of the methicillin-susceptible human lineage, but typically absent in LA-MRSA-CC398 strains), and lacked toxin-coding genes lukF/lukS-PV, tsst-1, eta and etb. Conclusion: IEC re-acquisition by LA-MRSA-CC398-LA strains is an unusual finding, but could constitute an emerging public health problem. It would represent an evolutionary step towards LA-MRSA-CC398's adaptation to human hosts, and might enhance its invasiveness and ability to be transmitted to humans (AU)

Objetivo: Caracterizar un aislado de Staphylococcus aureus resistente a meticilina (SARM), causante de una infección muy agresiva (absceso epidural y de psoas secundarios a artritis séptica hematógena) en un granjero avícola. Métodos: El aislado fue caracterizado molecularmente (spa- y multilocus sequence typing), y se estudió su fenotipo de resistencia y la presencia de genes de resistencia a tetraciclina, de virulencia y del sistema immune evasion cluster (IEC). Resultados: El aislado de SARM, resistente a tetraciclina y fluoroquinolonas, fue tipado como spa-t1451-CC398, albergaba el gen tet(M) (distintivo de SARM-CC398 asociado al ganado [AG]) y el sistema IEC-tipo B (característico de S. aureus meticilin-sensible-CC398 adscrito al clado humano, pero no de SARM-CC398-AG), carecía de lukF/lukS-PV, tsst-1, eta, y etb. Conclusión: La readquisición del sistema IEC por aislados SARM-CC398-AG es excepcional, pero constituiría un problema emergente de salud pública. Representaría un paso evolutivo en la readaptación de SARM-CC398-AG al hombre, pudiendo incrementar su invasividad y transmisibilidad a humanos (AU)

Heterozygous congenital Factor VII deficiency with the 9729del4 mutation, associated with severe spontaneous intracranial bleeding in an adolescent male.

BACKGROUND: In congenital Factor (F) VII deficiency bleeding phenotype and intrinsic FVII activity levels don't always correlate. Patients with FVII activity levels <30% appear to have a higher bleeding propensity, but bleeding can also occur at higher FVII activity levels. Reasons for bleeding at higher FVII activity levels are unknown, and it remains challenging to manage such patients clinically. CASE: A 19year old male with spontaneous intracranial hemorrhage and FVII activity levels of 44%, requiring emergent surgical intervention and a strategy for FVII replacement. Genotyping showed the rare heterozygous FVII 9729del4 mutation. Bleed evacuation was complicated by epidural abscess requiring craniectomy, bone graft procedures, and prolonged administration of recombinant human (rh) activated FVII (FVIIa). The patient recovered without neurological deficits, and remains on prophylactic low dose treatment with rhFVIIa in relation to risky athletic activities. CONCLUSION: For clinicians, it is important to recognize that effects of rhFVIIa within these pathways are independent of its contribution to blood clot formation and cannot be assessed by clotting assays. Reduced FVII levels should therefore not be dismissed, as even a mild reduction may result in spontaneous bleeding. Treatment of mild FVII deficiency requires a careful case-by-case approach, based on the clinical scenario.