Failure of Commercial Ligase Chain Reaction To Detect Mycobacterium tuberculosis DNA in Sputum Samples from a Patient with Smear-Positive Pulmonary Tuberculosis Due to a Deletion of the Target Region

We report on a strain of Mycobacterium tuberculosis with a deletion in the protein antigen B gene overlapping the probe binding sites for the Abbott Diagnostics LCx M. tuberculosis (LCx-MTB) probe assay. A false-negative result with the LCx-MTB assay delayed a laboratory diagnosis of tuberculosis.