The Great Masquerade: Recurrent Methicillin-resistant Staphylococcus aureus Catheter Bacteraemia Mimicking Spontaneous Bacterial Peritonitis: A Review of the Literature and Case Report

Introduction: Among the population of haemodialysis patients, the clinical harms of catheter-related bloodstream infection (CRBSI) have received widespread attention in clinical practice. CRBSI caused by methicillin-resistant Staphylococcus aureus (MRSA) is highly prone to misdiagnosis due to its atypical manifestations, leading to delays in diagnosis and treatment and thus posing a core clinical challenge. Results: A 64-year-old male patient with comorbid end-stage renal disease and liver cirrhosis, who presented for medical care with abdominal pain and tense ascites. His recurrent MRSA-associated bloodstream infection was initially misdiagnosed as spontaneous bacterial peritonitis. After a confirmed diagnosis was reached via blood culture and peritoneal effusion culture, the cuffed dialysis catheter placed during his previous admission was removed, and he was treated with intravenous vancomycin. Ultimately, his hemodynamic status stabilised, and he recovered smoothly. Conclusion: This case summary puts forward two core clinical diagnoses and treatment warnings: The first applies to patients seeking care who have multiple comorbidities and overlapping symptoms, requiring a differential diagnosis to distinguish between CRBSI and SBP; the second applies to haemodialysis patients with a history of MRSA infection, who require ongoing vigilance against recurrence even after their infection tests return negative.