A Further Numerical Taxonomic Study of the Rhodochrous Group

Matsumoto

International Journal of Systematic Bacteriology

et al. 1979

A numerical analysis of 369 strains received as members of the genus Mycobacterium, Rhodococcus (formerly Gordona) , Nocardia, or Corynebacterium was carried out using 88 characters. Of the strains tested, 345 mycobacteria, rhodococci, and nocardiae formed four distinct clusters at a similarity level of 85%. The first cluster was composed of slowly growing mycobacteria; the second cluster, of strains of Mycobacterium flavescens and M. thermoresistibile; the third cluster, of strains of rapidly growing mycobacteria; and the fourth cluster, of strains of Rhodococcus and Nocardia. Strains of three species of rapidly growing mycobacteria, M. agri, M. smegmatis, and M. vaccae, were located outside of these clusters. The fourth cluster could be divided into three subclusters, one consisting of rhodococci plus some strains of Nocardia asteroides, a second consisting of the remaining strains of Nocardia, and a third consisting of strains of Rhodococcus aurantiacus (Gordona aurantiaca) and Jensenia canicruria.Mycobacterium, Rhodococcus (formerly Gordona), and Nocardia are closely related taxa belonging to the order Actinomycetales (21).In 1966, Tsukamura (13) reported that mycobacteria can be divided into two subgroups, which roughly correspond to slowly growing and rapidly growing mycobacteria, by numerical classification. These two subgroups differed from each other not only in growth rate, but also in several biological characters. Subsequently, Tsukamura and Mizuno (14, 24) proposed the subgeneric names Mycobacterium and Mycomycobacterium for these subgroups. Later, after having compared mycobacteria and nocardiae, Tsukamura (17) recommended that the subgenera Myco bacterium (slowly growing mycobacteria) and Mycomycobacterium (rapidly growing mycobacteria) be elevated to genus status, i.e., taxa equivalent in status to the genus Nocardia.In 1971, Tsukamura (18) proposed a new genus, Gordona, for slightly acid-fast organisms considered to be intermediate between Mycobacterium and Nocardia and placed it in the family Actinomycetaceae, to which the genus Nocardia belongs. It was later shown by Tsukamura that the genus Gordona contained strain ATCC 13808 of Rhodococcus rhodochrous (19), and it was stated that the generic name Gordona should be changed to Rhodococcus (20), as this is the first name used for an organism belonging to the genus proposed. Independently, Goodfellow (2) observed that "Mycobacterium" rhodochrous differs from nocardiae, and Goodfellow et al. (4) reported that it also differs from rapidly growing mycobacteria.The finding that "M. " rhodochrous differs from both Mycobacterium and Nocardia was conf m e d by an international cooperative study (5). Goodfellow and Alderson (3) also proposed the name Rhodococcus for the "M. " rhodochrous complex, in which they included the genus Gordona. These authors also included several new species in the genus Rhodococcus.The taxonomic relationships of the mycobacteria, rhodococci, and nocardiae were studied by Tsukamura (21), who included hypothetical median organi...

Section: Discussionmentioning

confidence: 99%

Comprehensive Numerical Classification of 369 Strains of Mycobacterium, Rhodococcus, and Nocardia

Matsumoto

International Journal of Systematic Bacteriology

et al. 1979

“…terrae, R . rubropertinctus [17], R . sputi, and R. lentifragmentus [20]) and the three newly described species (R. aichiensis, R .…”

Section: * Corresponding Authormentioning

confidence: 99%

Rhodococcus sputi sp. nov., nom. rev., and Rhodococcus aurantiacus sp. nov., nom. rev.

International Journal of Systematic Bacteriology

Yano²

1985

In 1971 Tsukamura (16) proposed the generic name "Gordona" for slightly acid-fast organisms that were isolated from sputa of patients and from soil. At that time, the following three species were described: "Gordona bronchialis," "Gordona rubra," and "Gordona terrae." Later, after it was shown that this genus also contained the species Rhodococcus rhodochrous, it was proposed that members of the genus "Gordona" be transferred to the genus Rhodococcus (17). Tsukamura (17) described the following six species: Rhodococcus bronchialis, Rhodococcus rubropertinctus, Rhodococcus terrae, R . rhodochrous, Rhodococcus aurantiacus, and 'Rhodococcus roseus" (17). Goodfellow and Alderson (3, 6, 13) described three additional species (Rhodococcus erythropolis, Rhodococcus rhodonii, and Rhodococcus equi), and Rowbotham and Cross (11) described Rhodococcus coprophilus. In 1978 a full description of the genus Rhodococcus was published, and at the same time another species, Rhodococcus sputi, was described (20). More recently, Nesterrenko et al. (10) described Rhodococcus maris and Rhodococcus luteus, and Tsukamura (7, 25) added three species (Rhodococcus aichiensis, Rhodococcus chubuensis, and Rhodococcus obuensis).The morphological and physiological characteristics of the genus Rhodococcus have been described by Tsukamura (16, 20). Members of this genus contain mycolic acids with 30 to 66 carbon atoms and on this basis can be differentiated from members of the genus Mycobacterium, which have mycolic acids with 60 to 90 carbon atoms (1,2, 4, 8 , 9 , 12, 14, 30, 31). Rhodococci are also differentiated from mycobacteria by the absence of strong acid fastness and the absence of arylsulfatase activity (16). However, rhodococci are not convincingly differentiated from nocardiae by mycolic acid analysis, because members of these two genera produce the same mycolic acid pattern in thin-layer chromatograms (4,8, 14, 30, 31) and because the mycolic acids of rhodococci and nocardiae have the same range of carbon atom numbers (14, 21,30,31). Rhodococci may be differentiated from nocardiae by other characteristics, including the following three tests recently described by Tsukamura (22-24): susceptibility to 5-fluorouracil, susceptibility to mitomycin C, and susceptibility to bleomycin.The bacteria named R. sputi and R . aurantiacus (17, 20, 28) (names which were not included on the Approved Lists of Bacterial Names [13]) possess the characteristics of the genus Rhodococcus but are sufficiently distinct to warrant separate species status (25, 29). The name Rhodococcus

International Journal of Systematic and Evolutionary Microbiology

“…With the development of polyphasic procedures, the taxonomic positions of Rhodococcus species have undergone extensive changes over recent decades. The genus Rhodococcus was first described by Zopf (1891), reintroduced by Tsukamura (1974) and redefined by Goodfellow & Alderson (1977). At the time of writing, there are 40 species of the genus Rhodococcus with validly published names (Euzéby, 2007).…”

mentioning

confidence: 99%

Rhodococcus qingshengii sp. nov., a carbendazim-degrading bacterium

Wang

et al. 2007

A Gram-positive, aerobic, non-motile, mesophilic strain, djl-6 T , able to degrade carbendazim, was isolated from a carbendazim-contaminated soil sample from Jiangsu province, China. The taxonomic position of this isolate was analysed by using a polyphasic approach. Chemotaxonomic analysis including peptidoglycan type, diagnostic sugar composition, fatty acid profile, menaquinones, polar lipids and mycolic acids showed that the characteristics of strain djl-6 T were in good agreement with those of the genus Rhodococcus. DNA-DNA hybridization showed that it had low genomic relatedness with Rhodococcus baikonurensis DSM 44587 T (31.8 %), Rhodococcus erythropolis DSM 43066 T (23.8 %) and Rhodococcus globerulus DSM 43954 T (17.7 %), the three type strains to which strain djl-6 T was most closely related based on 16S rRNA gene sequence analysis (99.78, 99.25 and 98.91 % similarity, respectively). Based on the phenotypic properties and DNA-DNA hybridization data, strain djl-6 T (5CGMCC 1.6580 T 5KCTC 19205 T ) is proposed as the type strain of a novel Rhodococcus species, Rhodococcus qingshengii sp. nov.Members of the genus Rhodococcus are common in nature, possess a wide spectrum of catabolic activities and are able to survive under extremely harsh conditions, which makes them potentially useful in environmental and industrial biotechnology (Shao et al., 1995). With the development of polyphasic procedures, the taxonomic positions of Rhodococcus species have undergone extensive changes over recent decades. The genus Rhodococcus was first described by Zopf (1891), reintroduced by Tsukamura (1974) and redefined by Goodfellow & Alderson (1977). At the time of writing, there are 40 species of the genus Rhodococcus with validly published names (Euzéby, 2007).Strain djl-6 T , isolated in our laboratory as described below, is capable of degrading carbendazim efficiently (Xu et al., 2006). Carbendazim is one of the most widely used benzimidazole fungicides and is also a conversion product of benomyl and thiophanate-methyl. This fungicide can harm the liver and endocrine system and has mutagenic and teratogenic effects on animals, even at low concentrations (Mazellier et al., 2003). Microbial metabolism is the main mechanism of eliminating or minimizing contamination by carbendazim (WHO, 1993). To date, only a few pure cultures of bacteria with the ability to degrade carbendazim have been documented (Holtman & Kobayashi, 1997;Zhang et al., 2005a;Xu et al., 2006). Strain djl-6 T was isolated by selective enrichment from a carbendazim-contaminated soil sample from Jiangsu province, China, and grew well on Luria-Bertani (LB) medium or minimal medium with carbendazim as sole carbon and energy source at 30 u C (Xu et al., 2006). Rhodococcus baikonurensis DSM 44587 T , Rhodococcus erythropolis DSM 43066 T and Rhodococcus globerulus DSM 43954 T , used as reference organisms, were purchased from the Deutsche Sammlung von Mikroorganismen und Zellkulturen (Braunschweig, Germany), and were cultivated in tryptic soy broth at 30 u C (Zha...