Purple Urine Bag Syndrome (PUBS) is characterized by striking purple discoloration of the urine collection bag in patients with long-term urinary catheterization.1,2,5 Although uncommon in routine clinical practice, it has been described particularly among elderly, debilitated and institutionalized patients with indwelling catheters. ¹,²Reported prevalence among patients with long-term catheterization varies considerably. ²,⁵ Recognition is clinically useful because the appearance can cause considerable concern to patients, relatives and healthcare workers, while the underlying condition is often manageable with appropriate catheter care and treatment of associated infection when clinically indicated. The characteristic colour results from the conversion of dietary tryptophan to indole and subsequently to indoxyl sulphate. Bacterial enzymes, particularly sulfatases and phosphatases, convert indoxyl sulphate to indoxyl, which is oxidized to the pigments indigo and indirubin.¹,⁵ These pigments interact with the plastic of the urinary collection system and produce the characteristic purple appearance.¹,⁵ Organisms reported in association with PUBS include Providencia, Proteus, Klebsiella, Citrobacter, Enterobacter and other urinary pathogens.¹,²,⁵ We report six cases encountered in a tertiary-care hospital in Kerala, highlighting the clinical setting, microbiological findings, predisposing factors and short-term response to management.

This observational case series included six bedridden patients with prolonged indwelling urinary catheterization who developed purple discoloration of the urine collection bag. Available clinical and laboratory information was reviewed, including age, sex, diabetes status, constipation, duration of catheterization, urine culture organism and antibiotic sensitivity. All patients underwent catheter replacement and received culture-directed antimicrobial therapy as documented. Clinical outcome was assessed by resolution of the purple discoloration and overall clinical improvement

The six patients were aged 69–86 years. Two were women and four were men. All patients were bedridden following cerebrovascular accident and had been catheterized for more than three weeks. Constipation was present in all six patients. Diabetes mellitus was documented in three patients. Urine culture grew Klebsiella oxytoca in two patients, Escherichia coli in three patients and Providencia mirabilis in one patient. The purple discoloration resolved following catheter change and culture-directed antibiotic therapy. All patients showed clinical improvement within 2–3 days. Patient Age Sex Organism Antibiotic therapy* Diabetes Constipation Catheter duration 1 71 F Klebsiella oxytoca Piperacillin + [not documented] Yes Yes >3 weeks 2 73 F Klebsiella oxytoca Piperacillin + Tazobactam Yes Yes >3 weeks 3 86 M E. coli Piperacillin + Tazobactam Yes Yes >3 weeks 4 74 M E. coli Piperacillin + Tazobactam No Yes >3 weeks 5 77 M E. coli Piperacillin + Tazobactam No Yes >3 weeks 6 69 M Providencia mirabilis Ceftriaxone No Yes >3 weeks *Antibiotic information reflects the source case records; the regimen for patient 1 was incompletely documented in the source data.

PUBS is a striking clinical phenomenon most often encountered in older patients with prolonged urinary catheterization.¹,²,⁵ The present series had several recognized predisposing features: prolonged catheter use, immobility after cerebrovascular accident and constipation. All six patients had constipation, supporting the importance of altered bowel flora and increased intestinal bacterial metabolism in the pathogenesis of the syndrome.¹,²,⁵ Two patients were diabetic, although diabetes was not universal. The microbiological findings in this series included Klebsiella oxytoca, Escherichia coli and Providencia mirabilis. Providencia and other urease-producing or indoxyl-sulphatase/phosphatase-producing organisms have been repeatedly associated with PUBS.¹,²,⁵ The clinical appearance, however, should not be equated automatically with symptomatic urinary tract infection. Urinalysis and urine culture should be interpreted in the context of symptoms and the overall clinical condition, particularly in chronically catheterized patients where asymptomatic bacteriuria is common. Management should focus on the patient rather than the colour alone. Catheter and collection-bag replacement, adequate hydration, relief of constipation and good catheter hygiene are important measures. Antimicrobial treatment should be guided by clinical evidence of infection and culture susceptibility rather than by discoloration alone. In this case series, catheter replacement together with culture-directed antibiotic treatment was followed by resolution of discoloration and clinical improvement within 2–3 days. An important practical message is that PUBS can be alarming to patients and families despite often having a benign course. Early recognition can prevent unnecessary investigations and anxiety while ensuring that clinically significant urinary infection and contributing factors are appropriately addressed. Clinical Implications 1. Purple discoloration of a catheter bag should prompt recognition of PUBS and assessment of the patient's clinical status.¹,⁵ 2. Review for prolonged catheterization, constipation, dehydration and other predisposing factors.¹,²,⁵ 3. Obtain urine examination and culture when clinically indicated, and interpret results in context. 4. Replace the catheter and urinary collection system when appropriate and maintain proper catheter care. 5. Treat symptomatic or clinically significant infection with culture-directed antibiotics rather than treating urine discoloration alone. Limitations This was a small, single-centre observational case series of six patients. The study was descriptive and lacked a control group. Detailed laboratory parameters such as urine pH, renal function and quantitative microbiological counts were not available in the source dataset. Therefore, associations between individual risk factors and PUBS cannot be established causally.

PUBS is an uncommon but recognizable complication associated with prolonged urinary catheterization. In this six-case series, all patients were bedridden after cerebrovascular accident, had prolonged catheter use and constipation, and developed purple discoloration associated with urinary bacterial growth. Recognition, appropriate catheter care, assessment for clinically significant infection, correction of contributing factors and judicious culture-directed treatment resulted in rapid resolution. Awareness of PUBS among clinicians and caregivers may reduce anxiety and avoid unnecessary management while ensuring appropriate evaluation of the underlying patient.

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