Resistance to unspecified antibiotic

This code signifies that a bacterial infection is resistant to an antibiotic, but the specific antibiotic or class of antibiotics causing the resistance is not documented. It indicates a general, uncharacterized antimicrobial resistance impacting treatment options.

Apply this code when a patient's infection is confirmed to be resistant to an antibiotic, but the medical record does not specify which antibiotic or antibiotic class is ineffective. This is often used when initial broad-spectrum antibiotic treatment fails, and further specificity regarding resistance is pending or unknown.

• Only use this code when the specific antibiotic or class of resistance is truly unknown or unstated in the documentation.
• Avoid using this code if the documentation specifies resistance to a particular antibiotic (e.g., penicillin, methicillin); instead, use a more specific Z16.xx code.
• Always sequence this code as a secondary diagnosis, following the code for the underlying infection.