Indwelling Double J (DJ) ureteral stents are commonly used following lithotripsy to ensure adequate urinary drainage and prevent obstruction. However, stent-related biofilm formation remains a significant clinical problem, contributing to infection, encrustation, patient discomfort, and stent failure. Biofilms consist of microbial communities embedded within an extracellular polymeric substance (EPS), which protects microorganisms from host defenses and antimicrobial agents.

Antibiotic therapy alone may be insufficient to eradicate established biofilms due to poor penetration into the EPS matrix. Linezolid is a potent antibiotic with activity against gram-positive organisms commonly implicated in urinary tract colonization and penetrate and effectively act against bacterial biofilms. Mucolytic agents, by disrupting the biofilm matrix, may enhance antimicrobial penetration and reduce biofilm burden.

The combination of an antibiotic with a mucolytic agent may therefore provide superior biofilm reduction compared to either approach alone or no treatment.

Inclusion Criteria

• Adult patients (≥18 years).
• Undergoing lithotripsy (FURS, URS or PCNL) with DJ stent insertion.
• Stone free status.
• Planned stent indwelling time of 1 month.
• Negative preoperative urine culture.

Exclusion Criteria

• Known allergy or contraindication to linezolid or the selected mucolytic agent.
• Chronic kidney disease.
• Immunocompromised patients (e.g., chemotherapy, long-term steroid use).
• Pregnant or lactating women.