title: Nocardia kruczakiae sp. nov., a pathogen in immunocompromised patients and a member of the "N. nova complex".
abstract: Molecular methodologies have become useful techniques for the identification of pathogenic Nocardia species and for the recognition of novel species that are capable of causing human disease. Two isolates recovered from immunocompromised patients were characterized as Nocardia nova by biochemical and susceptibility testing results. The restriction fragment length polymorphism (RFLP) patterns obtained by restriction endonuclease analysis (REA) of an amplified portion of the heat shock protein gene were identical to those obtained with the type strain of N. nova. REA of an amplified portion of the 16S rRNA gene showed RFLP patterns that were unlike those obtained for the type strain of N. nova but that were similar to those obtained for the type strains of N. africana and N. veterana. Subsequent sequencing of a portion of the 16S rRNA gene produced identical results for the two patient isolates. Sequence analysis of 1,352-bp portions of the 16S rRNA gene indicated that these isolates were 99.8% similar to the recently described species N. veterana but were only 99.3, 98.1, and 98.1% similar to the type strains of N. africana, N. nova, and N. vaccinii, respectively. DNA-DNA hybridization studies confirmed that the two patient isolates belonged to the same species but were not closely related to N. africana, N. nova, N. vaccinii, or N. veterana. The patient isolates have been designated N. kruczakiae sp. nov. Because N. africana, N. veterana, and the new species are not readily differentiated from N. nova by phenotypic methods alone, the designation "N. nova complex" can be used to designate isolates such as these that phenotypically resemble N. nova but that have not been definitively characterized by 16S rRNA gene sequencing or DNA-DNA hybridization.
authors.affiliation: Microbiology Service, Department of Laboratroy Medicine, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892-1508, USA. pconville@nih.gov
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Conville
authors.forename: June M
authors.initials: JM
authors.lastname: Brown
authors.forename: Arnold G
authors.initials: AG
authors.lastname: Steigerwalt
authors.forename: Judy W
authors.initials: JW
authors.lastname: Lee
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Anderson
authors.forename: Joel T
authors.initials: JT
authors.lastname: Fishbain
authors.forename: Steven M
authors.initials: SM
authors.lastname: Holland
authors.forename: Frank G
authors.initials: FG
authors.lastname: Witebsky
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D015373:Bacterial Typing Techniques; D004269:DNA, Bacterial / Q000032:analysis; D004275:DNA, Ribosomal / Q000032:analysis; D005260:Female; D006360:Heat-Shock Proteins / Q000235:genetics; D006801:Humans; D016867:Immunocompromised Host; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D008969:Molecular Sequence Data; D009615:Nocardia / Q000145:classification* / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity; D009617:Nocardia Infections / Q000382:microbiology*; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D012150:Polymorphism, Restriction Fragment Length; D000091402:Prohibitins; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D015183:Restriction Mapping
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D006360:Heat-Shock Proteins; C000717331:PHB2 protein, human; D000091402:Prohibitins; D012336:RNA, Ribosomal, 16S