The second patient was a 36-year-old HIV-infected man with a 3-month history of fever and weight loss and 31 CD4 cells/mm3. He had been taking fixed-dose combination stavudine, lamivudine, and nevirapine for 5 months, but his adherence to therapy was poor. A mycobacterial blood culture grew acid-fast bacilli after 15 days of incubation; AccuProbe MTB and MAC test results were negative. Heat-killed cells from the positive blood culture were identified as M. simiae by the INNO-LiPA reverse-line blot and again as M. sherrisii by sequencing of the full 16S rDNA gene, ITS, and the hsp65 gene. The 16S rDNA gene had a single base-pair difference when compared with the M. sherrisii ATCC BAA-832 strain sequence in GenBank. We deposited the new 16S rDNA sequence in GenBank under accession no. EU883389. The hsp65 sequence was identical to the M. sherrisii ATCC BAA-832 strain sequence (accession no. AY365190); the ITS sequence was identical to the M. sherrisii strain FI-95229 (accession no. DQ185132) sequence. The patient was treated with azithromycin, 500 mg/day, and ethambutol, 800 mg/day; fever abated. At follow-up in 2008, the patient was continuing treatment with azithromycin and ethambutol but had abdominal pain and hepatosplenomegaly. Abdominal ultrasonography showed retroperitoneal lymphadenopathy. Follow-up mycobacterial blood cultures have been negative.