P138 | When a seemingly harmless commensal germ becomes a dangerous pathogen

Introduction: Staphylococcus capitis is a Gram-positive bacterium, commensal with the skin, but with the ability to cause endocarditis on prosthetic valves and more rarely on native ones.Case description: A 61-year-old man with a history of type 2 diabetes mellitus, HCV and HBV-related liver cirrhosis complicated by esophageal varices was admitted to the hospital for fever, modest ascites, cough and diarrhea. He had a moderately ascitic abdomen, painful and tender. On blood tests, slight increase in CRP. After performing blood cultures, ciprofloxacin was initiated in suspect of PBS. During hospitalization, a positive blood culture for Staphylococcus capitis at 22 hours was received. The transthoracic echocardiogram (TT) showed clear evidence of vegetation on the non-coronary cusp and a probably bicuspid aortic valve. There was a sudden onset of left upper limb weakness, with negative urgent brain CT and 24-hour follow-up showing presence of bilateral ischemic lesions. Brain MRI confirmed the suspicion of probable septic embolization. Therapy was started with oxacillin, ampicillin and gentamicin intravenously. There was a complete regression of hyposthenia and reduction of inflammation indices. After treatment, no more evident lesions on the TT echocardiography; TE not performed due to presence of esophageal varices; PET did not reveal any lesion.Conclusions: in the complexity of Medicine, even what may appear to be a simple contaminant can cause serious infections, especially in debilitated patients.