Characterization of a novel variant of Mycobacterium chimaera.
In this study, nonchromogenic mycobacteria were isolated from pulmonary samples of three patients in the Netherlands. All isolates had identical, unique 16S rRNA gene and 16S-23S ITS sequences, which were closely related to those of Mycobacterium chimaera and Mycobacterium marseillense. The biochemical features of the isolates differed slightly from those of M. chimaera, suggesting that the isolates may represent a possible separate species within the Mycobacterium avium complex (MAC). However, the cell-wall mycolic acid pattern, analysed by HPLC, and the partial sequences of the hsp65 and rpoB genes were identical to those of M. chimaera. We concluded that the isolates represent a novel variant of M. chimaera. The results of this analysis have led us to question the currently used methods of species definition for members of the genus Mycobacterium, which are based largely on 16S rRNA or rpoB gene sequencing. Definitions based on a single genetic target are likely to be insufficient. Genetic divergence, especially in the MAC, yields strains that cannot be confidently assigned to a specific species based on the analysis of a single genetic target.
Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
J
J
van Ingen
Department of Pulmonary Diseases, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
W
W
Hoefsloot
Department of Clinical Microbiology, Meander Medical Centre, Amersfoort, The Netherlands.
P C A M
PCAM
Buijtels
San Raffaele Scientific Institute, Milan, Italy.
E
E
Tortoli
Institut Pasteur de Lille, Center for Infection and Immunity of Lille, Lille, France.|Universite de Lille Nord de France, Lille, France.|INSERM U1019, France.|CNRS UMR 8204, France.
P
P
Supply
Department of Pulmonary Diseases, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
P N R
PNR
Dekhuijzen
Department of Pulmonary Diseases, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
M J
MJ
Boeree
National Mycobacteria Reference Laboratory, National Institute for Public Health and the Environment, Bilthoven, The Netherlands.|Department of Pulmonary Diseases, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.|Department of Medical Microbiology, Radboud University Nijmegen Medical Center, Nijmegen, The Netherlands.
D
D
van Soolingen
D000368:Aged; D000369:Aged, 80 and over; D015373:Bacterial Typing Techniques; D002908:Chronic Disease; D004269:DNA, Bacterial / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000032:analysis* / Q000235:genetics; D005260:Female; D020459:Genes, rRNA; D014644:Genetic Variation; D006801:Humans; D008171:Lung Diseases / Q000382:microbiology*; D008297:Male; D008969:Molecular Sequence Data; D015269:Mycobacterium avium Complex / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D015270:Mycobacterium avium-intracellulare Infection / Q000382:microbiology*; D009426:Netherlands; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013045:Species Specificity
D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S