Purple Urine Bag Syndrome as a Clinical Indicator of Bacteraemic Urosepsis Caused by Extensively Drug-resistant Escherichia coli: A Case Report

Purple Urine Bag Syndrome (PUBS) is an uncommon but clinically informative finding in catheterised patients, arising from bacterial enzymatic conversion of urinary indoxyl sulphate to indigo and indirubin within alkaline drainage tubing. Although usually benign in isolation, PUBS can signal severe underlying infection, constipation, alkaline urinary pH, and renal impairment. We report a 77-year-old man with diabetes mellitus and Chronic Kidney Disease (CKD stage 4) who presented with fever, dysuria, and altered sensorium. Following urinary catheterisation, purple-violet discolouration of the drainage tubing developed within six to eight hours, confirming PUBS on bedside assessment; the finding prompted urgent urine microscopy. Urine and blood cultures grew Extensively Drug-Resistant (XDR) Escherichia coli with an identical antibiogram, resistant to carbapenems, colistin, and the empirically administered antibiotic, with susceptibility retained only to fosfomycin and nitrofurantoin. He was treated with oral fosfomycin trometamol under nephrology guidance and discharged on day five with clinical resolution and improved renal function. Paired photographs documented the discolouration and its complete resolution within 24 hours. To our knowledge, this is the first photodocumented report of PUBS associated with bacteraemic XDR E. coli with concurrent carbapenem and colistin resistance from an emergency department in a low- and middle-income country setting. The case illustrates the value of PUBS as a bedside alarm sign that can accelerate recognition of severe multidrug-resistant sepsis, and underscores the importance of pre-antibiotic culture collection and prompt antimicrobial stewardship in catheterised elderly patients with systemic illness.