In this patient, resistance was created in successive steps by inappropriate chemotherapy.  The patient had initially probably an isoniazid resistant strain and acquired thus ethambutol-resistance in the continuation phase of the first-line regimen.  A single drug (rifampicin) was added to the failing regimen, then stopped and replaced by pyrazinamide alone.  Similar errors were made repeatedly with every drug available, and each drug was thus lost.  The dictum "never add a single drug to a failing regimen" was not heeded.  A patient failing treatment should always be treated with at least two drugs to which the organism is likely to be susceptible.

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