Emended description of Actinomyces naeslundii and descriptions of Actinomyces oris sp. nov. and Actinomyces johnsonii sp. nov., previously identified as Actinomyces naeslundii genospecies 1, 2 and WVA 963

Abstract

Actinomyces naeslundii is an important early colonizer in the oral biofilm and consists of three genospecies (1, 2 and WVA 963) which cannot be readily differentiated using conventional phenotypic testing or on the basis of 16S rRNA gene sequencing. We have investigated a representative collection of type and reference strains and clinical and oral isolates (n=115) and determined the partial gene sequences of six housekeeping genes (atpA, rpoB, pgi, metG, gltA and gyrA). These sequences identified the three genospecies and differentiated them from Actinomyces viscosus isolated from rodents. The partial sequences of atpA and metG gave best separation of the three genospecies. A. naeslundii genospecies 1 and 2 formed two distinct clusters, well separated from both genospecies WVA 963 and A. viscosus. Analysis of the same genes in other oral Actinomyces species (Actinomyces gerencseriae, A. israelii, A. meyeri, A. odontolyticus and A. georgiae) indicated that, when sequence data were obtained, these species each exhibited <90 % similarity with the A. naeslundii genospecies. Based on these data, we propose the name Actinomyces oris sp. nov. (type strain ATCC 27044T =CCUG 34288T) for A. naeslundii genospecies 2 and Actinomyces johnsonii sp. nov. (type strain ATCC 49338T =CCUG 34287T) for A. naeslundii genospecies WVA 963. A. naeslundii genospecies 1 should remain as A. naeslundii sensu stricto, with the type strain ATCC 12104T =NCTC 10301T =CCUG 2238T.

Species-Level Identification of Actinomyces Isolates Causing Invasive Infections: Multiyear Comparison of Vitek MS (Matrix-Assisted Laser Desorption Ionization–Time of Flight Mass Spectrometry) to Partial Sequencing of the 16S rRNA Gene

“…Our phylogenetic results confirm the species identification by the IDNS database; the majority of species identifications match well to publically available type strain sequences. There are some clusters of mixed species, such as those sharing recent common ancestry with A. oris and A. viscosus, supporting previous reports of heterogeneity within these species (28)(29)(30). Interestingly, our data also illustrate how diverse the oral taxons are, as shown by the dark (9) 47 (41) 15 (13) 43 (37) 115 a Includes the following species according to 16S sequencing: Actinomyces F507T (2), Actinomyces ARUP UnID 100, 97, 68, and 50 (4), Actinomyces 606220/2008 (1), Actinomyces GTC3949 (1), Actinomyces oral taxon 169, 170, 171, 172, 175, 180, and A50 (15), Actinomyces S8 86-2a (1), Actinomyces sp2-iso-aAG2 (3), and Actinomyces TeJ5 (2).…”

Actinomyces and Related Organisms in Human Infections

“…An additional genetic homology group, A. naeslundii genospecies WVA963, was also described. Multilocus sequence analysis has further clarified the relationships within this group, leading to a narrowing of the definition of A. naeslundii and the proposal of the new species A. oris for strains formerly assigned to A. naeslundii genospecies 2 and A. johnsonii for strains formerly assigned to genospecies WVA963 (10). Despite this work, human strains have continued to be assigned to A. viscosus, and it is often difficult to determine the taxon to which they belong in the current scheme.…”

“…Actinomyces organisms usually gain access to this area either by hematogenous spread from remote sites or directly from local actinomycotic lesions of the head, and the disease usually appears as a single or multiple brain abscesses; among 70 cases of actinomycosis in the CNS, two-thirds proved to be brain abscesses (142). Actinomyces species isolated from cerebrospinal fluid include A. israelii, from a patient with meningitis (107), and A. naeslundii (sensu stricto) (10). Clinicians should be aware of the possibility of actinomycosis in the CNS, especially in patients with neurological symptoms who have a history of actinomycosis elsewhere in the body (143).…”

“…In addition, reassignments within some species, such as A. naeslundii and A. viscosus, have occurred (10). However, only some human-associated Actinomyces species, including A. israelii, Actinomyces gerencseriae, and Actinomyces graevenitzii, may be involved in classical actinomycosis (11,12).…”

Genome-scale analysis of anaerobic benzoate and phenol metabolism in the hyperthermophilic archaeon Ferroglobus placidus

“…Expression of these three genes by F. placidus was stable under a variety of growth rates and conditions and none of them was differentially expressed in any of the microarray studies. Previous studies have used both metG and gyrA as controls for qRT-PCR analyses (Takle et al, 2007;Theis et al, 2007;Henssge et al, 2009). A DuraScript enhanced avian RT single-strand synthesis kit (Sigma) was used to generate cDNA as previously described (Holmes et al, 2004).…”