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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
What characteristic of struvite (ammonium magnesium phosphate) stones makes antibiotics ineffective when treatment is being performed?
assistant
The correct answer is  Bacteria inaccessible to antibiotics. Struvite calculi harbor infective bacteria within their interstices. Effective therapy must be directed to eradicate associated infection. Struvite stones are the second most common type of renal calculi after calcium oxalate stone.