Mycobacterium sediminis sp. nov. and Mycobacterium arabiense sp. nov., two rapidly growing members of the genus Mycobacterium

Mycolicibacterium arseniciresistens sp. nov., isolated from lead-zinc mine tailing, and reclassification of two Mycobacterium species as Mycolicibacterium palauense comb. nov. and Mycolicibacterium grossiae comb. nov

A Gram-positive, acid-fast, aerobic, rapidly growing and non-motile strain was isolated from lead-zinc mine tailing sampled in Lanping, Yunnan province, Southwest China. 16S rRNA gene sequence analysis showed that the most closely related species of strain KC 300T was Mycolicibacterium litorale CGMCC 4.5724T (98.47 %). Additionally, phylogenomic and specific conserved signature indel analysis revealed that strain KC 300T should be a member of genus Mycolicibacterium, and Mycobacterium palauense CECT 8779T and Mycobacterium grossiae DSM 104744T should also members of genus Mycolicibacterium. The genome size of strain KC 300T was 6.2 Mb with an in silico DNA G+C content of 69.2 mol%. Chemotaxonomic characteristics of strain KC 300T were also consistent with the genus Mycolicibacterium. The average nucleotide identity, digital DNA-DNA hybridization and average amino acid identity values, as well as phenotypic, physiological and biochemical characteristics, support that strain KC 300T represents a new species within the genus Mycolicibacterium, for which the name Mycolicibacterium arseniciresistens sp. nov. is proposed, with the type strain KC 300T (=CGMCC 1.19494T=JCM 35915T). In addition, we reclassified Mycobacterium palauense and Mycobacterium grossiae as Mycolicibacterium palauense comb. nov. and Mycolicibacterium grossiae comb. nov., respectively.

Description of Mycobacterium pinniadriaticum sp. nov., isolated from a noble pen shell (Pinna nobilis) population in Croatia

Introduction

Shortly before the mass mortality event of the noble pen shell (Pinna nobilis) population in the south-eastern Adriatic coast, two rapidly growing Mycobacterium strains CVI_P3T (DSM 114013 T, ATCC TSD-295 T) and CVI_P4 were obtained from the organs of individual mollusks during the regular health status monitoring.

Methods

The strains were identified as members of the genus Mycobacterium using basic phenotypic characteristics, genus-specific PCR assays targeting the hsp65 and 16S rRNA genes and the commercial hybridization kit GenoType Mycobacterium CM (Hain Lifescience, Germany). MALDI-TOF mass spectrometry did not provide reliable identification using the Bruker Biotyper Database.

Results and discussion

Genome-wide phylogeny and average nucleotide identity (ANI) values confirmed that the studied strains are clearly differentiated from their closest phylogenetic relative Mycobacterium aromaticivorans and other validly published Mycobacterium species (ANI ≤ 85.0%). The type strain CVI_P3T was further characterized by a polyphasic approach using both phenotypic and genotypic methods. Based on the phenotypic, chemotaxonomic and phylogenetic results, we conclude that strains CVI_P3T and CVI_P4 represent a novel species, for which the name Mycobacterium pinniadriaticum sp. nov. is proposed.

A nontuberculous mycobacterium could solve the mystery of the lady from the Franciscan church in Basel, Switzerland

BACKGROUND

In 1975, the mummified body of a female has been found in the Franciscan church in Basel, Switzerland. Molecular and genealogic analyses unveiled her identity as Anna Catharina Bischoff (ACB), a member of the upper class of post-reformed Basel, who died at the age of 68 years, in 1787. The reason behind her death is still a mystery, especially that toxicological analyses revealed high levels of mercury, a common treatment against infections at that time, in different body organs. The computed tomography (CT) and histological analysis showed bone lesions in the femurs, the rib cage, and the skull, which refers to a potential syphilis case.

RESULTS

Although we could not detect any molecular signs of the syphilis-causing pathogen Treponema pallidum subsp. pallidum, we realized high prevalence of a nontuberculous mycobacterium (NTM) species in brain tissue sample. The genome analysis of this NTM displayed richness of virulence genes and toxins, and similarity to other infectious NTM, known to infect immunocompromised patients. In addition, it displayed potential resistance to mercury compounds, which might indicate a selective advantage against the applied treatment. This suggests that ACB might have suffered from an atypical mycobacteriosis during her life, which could explain the mummy's bone lesion and high mercury concentrations.

CONCLUSIONS

The study of this mummy exemplifies the importance of employing differential diagnostic approaches in paleopathological analysis, by combining classical anthropological, radiological, histological, and toxicological observations with molecular analysis. It represents a proof-of-concept for the discovery of not-yet-described ancient pathogens in well-preserved specimens, using de novo metagenomic assembly.

Mycolicibacterium lacusdiani sp. nov., an Attached Bacterium of Microcystis aeruginosa

In eutrophic water, attached bacteria of Microcystis play an important role in the formation, development, and degradation of Microcystis blooms. A novel actinobacterium, designated as JXJ CY 35^T, was isolated from the culture mass of Microcystis aeruginosa FACHB-905 (Maf) collected from Lake Dianchi, Yunnan Province, China. Strain JXJ CY 35^T was gram-positive, acid-fast staining, aerobic, with short rod-shaped cells, positive for catalase, and negative for oxidase. The isolate was able to grow at 10.0–36.0°C, pH 4.0–10.0, and tolerate up to 5.0% (w/v) NaCl, with optimal growth at 28°C, pH 7.0–8.0, and 0% (w/v) NaCl. Cell-wall peptidoglycan contains aspartic acid, glutamic acid, glycine, and alanine, with mannose, ribose, galactose, and arabinose as whole-cell sugars. Polar lipids consist of diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), glycolipid (GL1-3), phosphoglycolipid (PGL), phosphatidylinositol (PI), and unidentified lipid (L1). The predominant menaquinone was MK-9. Major fatty acids (>10%) were C_17:1ω7c (37.0%) and C_18:1ω9c (18.9%). The complete genome sequence of strain JXJ CY 35^T was 6,138,096 bp in size with a DNA G + C content of 68.3%. Based on 16S rRNA gene sequences, it has 98.2% similarity to Mycolicibacterium arabiense JCM 18538^T. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values between strain JXJ CY 35^T and the closest five type strains M. arabiense JCM 18538^T, M. goodii ATCC 700504^T, M. mageritense DSM 44476^T, M. austroafricanum DSM 44191^T, and Mycobacterium neglectum CECT 8778^T were 52.1, 20.3, 20.3, 20.6, and 19.8%, and 92.7, 75.5, 75.6, 76.0, and 75.2%, respectively. On the basis of the above taxonomic data and differences in physiological characteristics from the closely related type strain, strain JXJ CY 35^T was determined to represent a novel species of genus Mycolicibacterium, for which the name Mycolicibacterium lacusdiani sp. nov., is proposed. The type strain is JXJ CY 35^T (=KCTC 49379^T = CGMCC 1.17501^T). Different inoculation dosages of the type strain JXJ CY 35^T could exhibit different effects on the growth of Maf and its toxin synthesis and release. Strain JXJ CY 35^T could promote the growth of Maf by providing it with available phosphorus, nitrogen, probably vitamins, and plant growth hormones.

Mycolicibacterium baixiangningiae sp. nov. and Mycolicibacterium mengxianglii sp. nov., two new rapidly growing mycobacterial species

Four bacterial strains (LJ126^T/S18 and Z-34^T/S20) recovered from faecal samples of Tibetan antelopes on the Qinghai-Tibet Plateau of China were analysed using a polyphasic approach. All four isolates were aerobic, short rod-shaped, non-motile, Gram-stain-positive, acid-fast and fast-growing. Phylogenetic analyses based upon 16S rRNA and whole-genome sequences showed that the two pair of strains formed two distinct branches within the evolutionary radiation of the genus Mycolicibacterium. Strains LJ126^T/S18 and Z-34^T/S20 were most closely related to Mycolicibacterium austroafricanum CCUG 37667^T, Mycobacterium aurum NCTC 10437^T, Mycobacterium pyrenivorans DSM 44605^T, Mycobacterium monacense JCM 15658^T, Mycolicibacterium sarraceniae JCM 30395^T, Mycolicibacterium tokaiense JCM 6373^T and Mycobacterium murale JCM 13392^T, but readily distinguished from the known species by a combination of chemotaxonomic and phenotypic features and by low average nucleotide identity values (74.4-84.9 %). Consequently, the two strain pairs are considered to represent different novel species of Mycolicibacterium for which the names Mycolicibacterium baixiangningiae sp. nov. and Mycolicibacterium mengxianglii sp. nov. are proposed, with LJ126^T (=CGMCC 1.1992^T=KCTC 49535^T) and Z-34^T (=CGMCC 1.1993^T=DSM 106172^T) as the respective type strains.

Genomic molecular signatures determined characterization of Mycolicibacterium gossypii sp. nov., a fast-growing mycobacterial species isolated from cotton field soil

A Gram-positive, acid-fast and rapidly growing rod, designated S2-37 ^T, that could form yellowish colonies was isolated from one soil sample collected from cotton cropping field located in the Xinjiang region of China. Genomic analyses indicated that strain S2-37 ^T harbored T7SS secretion system and was very likely able to produce mycolic acid, which were typical features of pathogenetic mycobacterial species. 16S rRNA-directed phylogenetic analysis referred that strain S2-37 ^T was closely related to bacterial species belonging to the genus Mycolicibacterium, which was further confirmed by pan-genome phylogenetic analysis. Digital DNA-DNA hybridization and the average nucleotide identity presented that strain S2-37 ^T displayed the highest values of 39.1% (35.7-42.6%) and 81.28% with M. litorale CGMCC 4.5724 ^T, respectively. And characterization of conserved molecular signatures further supported the taxonomic position of strain S2-37 ^T belonging to the genus Mycolicibacterium. The main fatty acids were identified as C_16:0, C_18:0, C_20:3ω3 and C_22:6ω3. In addition, polar lipids profile was mainly composed of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylinositol. Phylogenetic analyses, distinct fatty aids and antimicrobial resistance profiles indicated that strain S2-37 ^T represented genetically and phenotypically distinct from its closest phylogenetic neighbour, M. litorale CGMCC 4.5724 ^T. Here, we propose a novel species of the genus Mycolicibacterium: Mycolicibacterium gossypii sp. nov. with the type strain S2-37 ^T (= JCM 34327 ^T = CGMCC 1.18817 ^T).

Mycobacterium vicinigordonae sp. nov., a slow-growing scotochromogenic species isolated from sputum

A slow-growing, scotochromogenic mycobacterial strain (24^T) was isolated from the sputum of a Chinese male human. Phylogenetic analysis using the 16S rRNA gene assigned strain 24^T to the Mycobacterium gordonae complex, which includes Mycobacterium gordonae and Mycobacterium paragordonae. The phenotypic characteristics, unique mycolic acid profile and the results of phylogenetic analysis based on hsp65 and rpoB sequences strongly supported the taxonomic status of strain 24^T as a representative of a species distinct from the other members of the M. gordonae complex. The genomic G+C content of strain 24^T was 65.40mol%. Genomic comparisons showed that strain 24^T and M. gordonae ATCC 14470^T had an average nucleotide identity (ANI) value of 81.00 % and a DNA-DNA hybridization (DDH) value of 22.80 %, while the ANI and DDH values between strain 24^Tand M. paragordonae 49 061^T were 80.98 and 22.80 %, respectively. In terms of phylogenetic, phenotypic and chemotaxonomic features, strain 24^T is distinguishable from its closest phylogenetic relatives and represents a novel species of the genus Mycobacterium, therefore the name Mycobacterium vicinigordonae sp. nov. is proposed. The type strain is 24^T (=CMCC 93559^T=DSM 105979^T).

Nontuberculous mycobacteria in the environment of Hranice Abyss, the world's deepest flooded cave (Hranice karst, Czech Republic)

Nontuberculous mycobacteria (NTM) are widely distributed in the environment. On one hand, they are opportunistic pathogens for humans and animals, and on the other hand, they are effective in biodegradation of some persistent pollutants. Following the recently recorded large abundance of NTM in extreme geothermal environments, the aim of the study was to ascertain the occurrence of NTM in the extreme environment of the water zone of the Hranice Abyss (HA). The HA mineral water is acidic, with large concentrations of free CO₂, and bacterial slimes creating characteristic mucilaginous formations. Both culture and molecular methods were used to compare the mycobacterial diversity across the linked but distinct ecosystems of HA and the adjacent Zbrašov Aragonite Caves (ZAC) with consideration of their pathogenic relevance. Six slowly growing NTM species (M. arupense, M. avium, M. florentinum, M. gordonae, M. intracellulare) and two rapidly growing NTM species (M. mucogenicum, M. sediminis) were identified in the water and in the dry zones at both sites. Proteobacteria were dominant in all the samples from both the HA and the ZAC. The bacterial microbiomes of the HA mineral water and HA slime were similar, but both differed from the microbiome in the ZAC mineral water. Actinobacteria, a phylum containing mycobacteria, was identified in all the samples at low proportional abundance. The majority of the detected NTM species belong among environmental opportunistic pathogens.

Phylogenomics and Comparative Genomic Studies Robustly Support Division of the Genus Mycobacterium into an Emended Genus Mycobacterium and Four Novel Genera

The genus Mycobacterium contains 188 species including several major human pathogens as well as numerous other environmental species. We report here comprehensive phylogenomics and comparative genomic analyses on 150 genomes of Mycobacterium species to understand their interrelationships. Phylogenetic trees were constructed for the 150 species based on 1941 core proteins for the genus Mycobacterium, 136 core proteins for the phylum Actinobacteria and 8 other conserved proteins. Additionally, the overall genome similarity amongst the Mycobacterium species was determined based on average amino acid identity of the conserved protein families. The results from these analyses consistently support the existence of five distinct monophyletic groups within the genus Mycobacterium at the highest level, which are designated as the "Tuberculosis-Simiae," "Terrae," "Triviale," "Fortuitum-Vaccae," and "Abscessus-Chelonae" clades. Some of these clades have also been observed in earlier phylogenetic studies. Of these clades, the "Abscessus-Chelonae" clade forms the deepest branching lineage and does not form a monophyletic grouping with the "Fortuitum-Vaccae" clade of fast-growing species. In parallel, our comparative analyses of proteins from mycobacterial genomes have identified 172 molecular signatures in the form of conserved signature indels and conserved signature proteins, which are uniquely shared by either all Mycobacterium species or by members of the five identified clades. The identified molecular signatures (or synapomorphies) provide strong independent evidence for the monophyly of the genus Mycobacterium and the five described clades and they provide reliable means for the demarcation of these clades and for their diagnostics. Based on the results of our comprehensive phylogenomic analyses and numerous identified molecular signatures, which consistently and strongly support the division of known mycobacterial species into the five described clades, we propose here division of the genus Mycobacterium into an emended genus Mycobacterium encompassing the "Tuberculosis-Simiae" clade, which includes all of the major human pathogens, and four novel genera viz. Mycolicibacterium gen. nov., Mycolicibacter gen. nov., Mycolicibacillus gen. nov. and Mycobacteroides gen. nov. corresponding to the "Fortuitum-Vaccae," "Terrae," "Triviale," and "Abscessus-Chelonae" clades, respectively. With the division of mycobacterial species into these five distinct groups, attention can now be focused on unique genetic and molecular characteristics that differentiate members of these groups.

Practice Guidelines for Clinical Microbiology Laboratories: Mycobacteria

Mycobacteria are the causative organisms for diseases such as tuberculosis (TB), leprosy, Buruli ulcer, and pulmonary nontuberculous mycobacterial disease, to name the most important ones. In 2015, globally, almost 10 million people developed TB, and almost half a million patients suffered from its multidrug-resistant form. In 2016, a total of 9,287 new TB cases were reported in the United States. In 2015, there were 174,608 new case of leprosy worldwide. India, Brazil, and Indonesia reported the most leprosy cases. In 2015, the World Health Organization reported 2,037 new cases of Buruli ulcer, with most cases being reported in Africa. Pulmonary nontuberculous mycobacterial disease is an emerging public health challenge. The U.S. National Institutes of Health reported an increase from 20 to 47 cases/100,000 persons (or 8.2% per year) of pulmonary nontuberculous mycobacterial disease among adults aged 65 years or older throughout the United States, with 181,037 national annual cases estimated in 2014. This review describes contemporary methods for the laboratory diagnosis of mycobacterial diseases. Furthermore, the review considers the ever-changing health care delivery system and stresses the laboratory's need to adjust and embrace molecular technologies to provide shorter turnaround times and a higher quality of care for the patients who we serve.

Rapidly Growing Mycobacteria

Rapidly growing mycobacteria (RGM) compose approximately one-half of the currently validated mycobacterial species and are divided into six major groups, including the Mycobacterium fortuitum group, M. chelonae/M. abscessus complex, M. smegmatis group, M. mucogenicum group, M. mageritense / M. wolinskyi , and the pigmented RGM. This review discusses each group and highlights the major types of infections associated with each group. Additionally, phenotypic and molecular laboratory identification methods, including gene sequencing, mass spectrometry, and the newly emerging whole-genome sequencing, are detailed, along with a discussion of the current antimicrobial susceptibility methods and patterns of the most common pathogenic species.

Microbiological features and clinical relevance of new species of the genus Mycobacterium

Nontuberculous mycobacteria (NTM) are present in the environment, mainly in water, and are occasionally responsible for opportunistic infections in humans. Despite the fact that NTM are characterized by a moderate pathogenicity, the diseases caused by NTM at various body sites are increasing on a worldwide level. Among over 150 officially recognized NTM species, only two or three dozen are familiar to clinicians, and even to most microbiologists. In this paper, approximately 50 new species described in the last 8 years are reviewed, and their role in human infections is assessed on the basis of reported clinical cases. The small number of reports concerning most of the "new" mycobacterial species is responsible for the widespread conviction that they are very rare. Their role is actually largely underestimated, mainly because they often remain unrecognized and misidentified. Aiming to minimize such bias, emphasis has been placed on more common identification pitfalls. Together with new NTM, new members of the Mycobacterium tuberculosis complex described in the last few years are also an object of the present review.

Actinophytocola sediminis sp. nov., an actinomycete isolated from a marine sediment

A novel actinomycete strain, designated YIM M13705(T), was isolated from a marine sediment sample of the South China Sea and its characteristics were determined by a polyphasic approach. The slowly growing, Gram-stain-positive, aerobic strain produced branched substrate mycelium and aerial hyphae, and no diffusible pigment was produced on the media tested. At maturity, spore chains were formed on aerial hyphae and substrate mycelium was not fragmented. Whole-cell hydrolysates of the strain contained meso-diaminopimelic acid and galactose, glucose, ribose and rhamnose. The predominant menaquinones were MK-9(H4) and MK-10(H2). The polar lipids detected were diphosphatidylglycerol, phosphatidylethanolamine, hydroxyphosphatidylethanolamine, phosphatidylinositol and ninhydrin-positive phosphoglycolipids. The major fatty acid was iso-C(16 : 0). The G+C content of the genomic DNA was 68.2 mol%. On the basis of 16S rRNA gene sequence, the strain was shown to be most closely related to species of the genus Actinophytocola. DNA-DNA hybridization relatedness values (<70%) of the isolate with its closest neighbour Actinophytocola xinjiangensis QAIII60(T) supported classification of the isolate as a representative of a novel species. On the basis of phylogenetic analysis, and phenotypic and genotypic data, it is concluded that the new isolate belongs to a novel species of the genus Actinophytocola, for which the name Actinophytocola sediminis sp. nov. (type strain YIM M13705(T) = DSM 45939(T) = BCRC 16956(T)) is proposed.

Mariniluteicoccus flavus gen. nov., sp. nov., a new member of the family Propionibacteriaceae, isolated from a deep-sea sediment

A Gram-staining-positive, aerobic, non-motile, irregular coccus, designated strain YIM M13146(T), was isolated from a sediment sample collected from the South China Sea at a depth of 2439 m, and its taxonomic position was determined by a polyphasic approach. Optimal growth of the strain was observed at 30 °C (range 5-40 °C), pH 7.0 (pH 6.0-9.0) and 0-1% NaCl (0-6%, w/v) on/in tryptic soy agar/broth. Strain YIM M13146(T) had the major cellular fatty acid anteiso-C15:0, the predominant respiratory menaquinone MK-9(H4), peptidoglycan type A3γ (ll-DAP-Gly) containing alanine, glycine, glutamic acid and ll-diaminopimelic acid (ll-DAP) and the polar lipids phosphatidylcholine, diphosphatidylglycerol, one unknown phospholipid and several glycolipids. The G+C content of the DNA was 67.2 mol%. Phenotypic and chemotaxonomic characteristics together with 16S rRNA gene sequence analyses showed that strain YIM M13146(T) was distinct from its close phylogenetic relatives in the genera Propioniferax and Granulicoccus of the family Propionibacteriaceae. Hence, a new genus and species, Mariniluteicoccus flavus gen. nov., sp. nov., is proposed. The type strain of Mariniluteicoccus flavus is YIM M13146(T) ( = DSM 25892(T) = CCTCC AB 2012055(T)).