Mycobacterium neoaurum and Mycobacterium bacteremicum sp. nov. as causes of mycobacteremia.
Reference isolates of Mycobacterium neoaurum, Mycobacterium aurum, and the nonvalidated species "Mycobacterium lacticola" were the focus of two recent molecular taxonomic studies. On the basis of this grouping, we identified 46 clinical pigmented, rapidly growing mycobacterial isolates. By 16S rRNA gene sequencing, only two major taxa were identified: M. neoaurum and a previously uncharacterized "M. neoaurum-like" group. The M. neoaurum-like group exhibited only 99.7% identity to M. neoaurum by 16S rRNA gene sequencing and 96.5% identity to M. neoaurum by rpoB sequencing and was named M. bacteremicum. No clinical isolates of M. aurum or M. lacticola were identified. Of isolates with known sources, 4/8 (50%) of M. bacteremicum isolates and 22/34 (65%) of M. neoaurum isolates were recovered from blood, and 35% of these were known to be from patients with catheter-related sepsis. MIC and clinical data on these 46 isolates of M. neoaurum and M. bacteremicum along with a review of 16 previously reported cases of infection with the M. neoaurum-M. lacticola group demonstrated that the isolates were highly susceptible to all drugs tested except clarithromycin, and most clinical cases were successfully treated. The clarithromycin resistance suggested the presence of an inducible erm gene reported in other species of rapidly growing mycobacteria. Sequencing studies are currently required to identify these two species. Strain ATCC 25791 (originally submitted as an example of Mycobacterium aurum) is proposed to be the type strain of M. bacteremicum.
Brown-Elliott
Barbara A
BA
The University of Texas Health Science Center at Tyler, Department of Microbiology, 11937 U.S. Hwy. 271, Tyler, TX 75708, USA. barbara.elliott@uthct.edu
Wallace
Richard J
RJ
Petti
Cathy A
CA
Mann
Linda Bridge
LB
McGlasson
Maria
M
Chihara
Shingo
S
Smith
Geremy L
GL
Painter
Patrick
P
Hail
Daymon
D
Wilson
Rebecca
R
Simmon
Keith E
KE
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016470:Bacteremia / Q000382:microbiology*; D055499:Catheter-Related Infections / Q000382:microbiology; D002648:Child; D002675:Child, Preschool; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008969:Molecular Sequence Data; D009161:Mycobacterium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification*; D009164:Mycobacterium Infections / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit