Paenimyroides aestuarii gen. nov. sp. nov., a novel bacterium isolated from sediment in the Pearl River Estuary and reclassification of five Flavobacterium and four Myroides species

An aerobic, Gram-negative, non-motile, yellow-to-orange pigmented and round bacterium, designated strain SCSIO 72103T, was isolated from sediment collected in the Pearl River Estuary, Guangdong Province, PR China and subjected to a polyphasic taxonomic study. Growth occurred at 20-37 °C (optimum, 28 °C), pH 6-8 (optimum, pH 7) and with 1-5.5% NaCl (optimum, 1-3 %). Comparative 16S rRNA gene analysis indicated that strain SCSIO 72103T had the highest similarities to Flavobacterium baculatum SNL9T (94.7 %) and Myroides aquimaris SW105T (94.2 %). Phylogenetic analysis based 16S rRNA gene sequences showed that strain SCSIO 72103T formed a single clade with M. aquimaris SW105T. Strain SCSIO 72103T contained iso-C15 : 0 as the major fatty acid and the predominant respiratory quinone was menaquinone MK-6. These characteristics are consistent with those of F. baculatum SNL9T and M. aquimaris SW105T. Phosphatidylethanolamine, most notably, unidentified aminolipid and unidentified aminophospholipid were major polar lipids. Strain SCSIO 72103T had a single circular chromosome of 2.96 Mb with a DNA G+C content of 35.1 mol%. The average nucleotide identity, average amino acid identity (AAI) and digital DNA-DNA hybridization values showed that the pairwise similarities between SCSIO 72103T and the type strains of F. baculatum SNL9T and M. aquimaris SW105T were 78.5-80.5 %, 79.0-81.4 % and 22.7-22.8 %, respectively. The AAI values between species in this clade and the type species of Flavobacterium and Myroides were below the 65 % threshold, indicating that these species belong to a novel genus. On the basis of phylogenetic, physiological and chemotaxonomic characteristics, strain SCSIO 72103T represents a new species of a novel genus, for which the name Paenimyroides aestuarii gen. nov. sp. nov. is proposed. The type strain is SCSIO 72103T (=KCTC 92043T=MCCC 1K06659T). It is also proposed that nine known species in the genera Flavobacterium and Myroides are reclassified as Paenimyroides species.

Myroides fluvii sp. nov., isolated from the Han River, Republic of Korea

A Gram-stain-negative, aerobic, short rod-shaped, pale yellow-pigmented, non-motile and gentamycin-resistant bacterial strain designated CJ210^T was isolated from the Han River, Republic of Korea. Strain CJ210^T grew optimally at 30 °C and pH 7.0 in the absence of NaCl on tryptic soy agar. Flexirubin-type pigments were not produced. Phylogenetic analysis based on 16S rRNA gene sequence similarity showed that strain CJ210^T belonged to the genus Myroides within the family Flavobacteriaceae and was most closely related to Myroides odoratus KACC 14347^T (98.1 % similarity), followed by M. injenensis KCTC 23367^T (95.3 % similarity). The average nucleotide identity values between strain CJ210^T and two closely related type strains M. odoratus KACC 14347^T and M. injenensis KCTC 23367^T were 83.7 and 73.8 %, respectively. The digital DNA-DNA hybridization results between strain CJ210^T and the related type strains were 27.5 and 20.2 %, respectively. Strain CJ210^T contained menaquinone 6 (MK-6) as the predominant menaquinone. The predominant polar lipids were phosphatidylethanolamine, two unidentified aminolipids and two unidentified lipids. The major fatty acids of strain CJ210^T were iso-C_15 : 0, iso-C_17 : 0 3-OH and summed feature 9 (comprising iso-C_17 : 1  ω9c and/or C_16 : 0 10-methyl). Whole genome sequencing revealed that strain CJ210^T had a genome of 3.8 Mbp with 36.5 % DNA G+C content. The genome contained several antimicrobial resistance genes including an aminoglycoside-resistant gene. On the basis of the polyphasic taxonomic study, strain CJ210^T represents a novel species in the genus Myroides, for which name Myrodies fluvii sp. nov. is proposed. The type strain is CJ210^T (=KACC 19954^T=JCM 33306^T).

Myroides albus sp. nov., isolated from the gut of plastic-eating larvae of the coleopteran insect Zophobas atratus

A bacterial strain, BIT-d1T, was isolated from the gut of plastic-eating larvae of the coleopteran insect Zophobas atratus. Its taxonomic position was analysed using a polyphasic approach. Cells were white-pigmented, Gram-stain-negative, non-motile, long rods without flagella. The 16S rRNA gene sequence (1401 bp) of strain BIT-d1T showed highest similarity (98.0%) to Myroides pelagicus SM1T and 96.6~92.6 % similarity to the other species of the genus Myroides . The results of phylogenetic analyses, based on the 16S rRNA gene, concatenated sequences of six housekeeping genes (gyrB, dnaK, tuf, murG, atpA and glyA) and genome sequences, placed strain BIT-d1T in a separate lineage among the genus Myroides , family Flavobacteriaceae . The major isoprenoid quinone was menaquinone-6 (MK-6) and the major fatty acids were C15 : 0 iso, C17 : 0 iso 3-OH and summed feature 9 (comprising iso-C17 : 1  ω9c and/or C16 : 0 10-methyl), which were similar to other members in the genus Myroides. In silico DNA–DNA hybridization and average nucleotide identity calculations plus physiological and biochemical tests exhibited the genotypic and phenotypic differentiation of strain BIT-d1T from the other members of the genus Myroides . Therefore, strain BIT-d1T is considered to represent a novel species within the genus Myroides , for which the name Myroides albus sp. nov is proposed. The type strain is BIT-d1T (=CGMCC 1.17043T=KCTC 72447T).

Avrilella dinanensis gen. nov., sp. nov., a novel bacterium of the family Flavobacteriaceae isolated from human blood

Polyphasic taxonomic analysis was performed on a novel bacterium, designated UR159^T, isolated in 2016 from human blood of a septic patient hospitalized in France. Preliminary 16S rRNA gene sequence-based phylogenetic analysis indicated that strain UR159^T belonged to the family Flavobacteriaceae, forming a distinct phyletic line distantly related (<94% sequence similarity) to known species of the family. Further phenotypic, chemotaxonomic and genomic analyses were performed. Cells were non-motile, oxidase-negative, catalase-positive Gram-negative rods. It was strictly aerobic yielding yellow-pigmented colonies, and was metabolically rather inert. Major fatty acids were iso-branched fatty acids, predominantly iso-C_15:0 (55.5%) and iso-C_17:1ω9c (8.8%). Whole genome sequencing revealed a 2.3-Mbp genome encoding a total of 2262 putative genes with a genomic DNA G+C content at 37.6mol%. The average nucleotide identity (ANI) and in silico DNA-DNA hybridization (isDDH) values between strain UR159^T and the most closely related members of the Flavobacteriaceae family were <75% and <39%, respectively, much below the established cut-offs for ANI (<95-96%) and isDDH (<70%) for species and genus delineation. Average Amino Acid Identity (AAI) percentages were also estimated and were lower than 65% (cut-off proposed for genus delineation for uncultivated prokaryotes) in all cases, except for F. marinum that was just at the limit (65.1%). Based on these findings, we propose it as a new genus and species, Avrilella dinanensis gen. nov., sp. nov. (type strain UR159^T=CIP 111616^T=DSM 105483^T).

Art-omics: multi-omics meet archaeology and art conservation

Multi-omics can informally be described as the combined use of high-throughput techniques allowing the characterization of complete microbial communities by the sequencing/identification of total pools of biomolecules including DNA, proteins or metabolites. These techniques have allowed an unprecedented level of knowledge on complex microbial ecosystems, which is having key implications in land and marine ecology, industrial biotechnology or biomedicine. Multi-omics have recently been applied to artistic or archaeological objects, with the goal of either contributing to shedding light on the original context of the pieces and/or to inform conservation approaches. In this minireview, we discuss the application of -omic techniques to the study of prehistoric artworks and ancient man-made objects in three main technical blocks: metagenomics, proteomics and metabolomics. In particular, we will focus on how proteomics and metabolomics can provide paradigm-breaking results by unambiguously identifying peptides associated with a given, palaeo-cultural context; and we will discuss how metagenomics can be central for the identification of the microbial keyplayers on artworks surfaces, whose conservation can then be approached by a range of techniques, including using selected microorganisms as 'probiotics' because of their direct or indirect effect in the stabilization and preservation of valuable art objects.

A Confirmed Catheter-Related Blood Stream Infection (CRBSI) in an Immunocompetent Patient Due to Myroides odoratimimus: Case Report and Literature Review

The genus Myroides are gram-negative bacilli which are completely aerobic, non-motile, non-fermenting and yellow-pigmented with a characteristic fruity odor. Myroides species are widely found in the environment, especially in water and soil, and are considered as low-grade opportunistic pathogens for humans. Myroides infections are most commonly seen in immunocompromised patients and only rarely occur in immunocompetent patients. We here report the first confirmed catheter-related bloodstream infection (CRBSI) due to Myroides odoratimimus in an immunocompetent patient. We also review the literature related to Myroides infections.

Association of Myroides odoratimimus in immunocompromized piglets with post weaning multisystemic wasting syndrome

AIM

To study the association of opportunistic infection due to Myroides odoratimimus in piglets immunocompromised by porcine circovirus type 2 (PCV2) infection.

METHODS AND RESULTS

The clinical samples (n = 101) were analysed bacteriologically. The isolates were identified by their phenotypes and MALDI TOF-MS analysis as Myroides species. The phylogram constructed based on nucleotide sequences of the 16S rRNA gene showed identity (~99%) with the M. odoratimimus isolates. The minimum inhibitory concentration values for antibiotics revealed M. odoratimimus to be resistant against carbapenem, cephalosporins, aminoglycosides and fluoroquinolones. The presence of PCV2 in affected tissue samples was confirmed by amplification of the 565 bp region of ORF2 of the PCV2 genome. The topology of the phylogenetic tree grouped the PCV2 with cluster-2d.

CONCLUSIONS

PCV2 being immunosuppressive in nature might have impaired the immunity thereby increasing the susceptibility of immunocompromised piglets to opportunistic pathogens such as M. odoratimimus leading to disease severity and high mortality. The M. odoratimimus isolates were found to be multidrug resistant and evidenced for uncertain clinical relevance and hence could act as hidden source of public health hazard.

SIGNIFICANCE AND IMPACT OF THE STUDY

Myroides odoratimimus is a rarely reported human pathogen. We reported the incidence of infection due to seemingly rare isolates of M. odoratimimus causing an outbreak of pneumonia in piglets. This appears, to the best of authors' knowledge, to be the first outbreak due to Myroides recorded in animal clinical cases described in the literature.

Whole-genome sequencing of a large collection of Myroides odoratimimus and Myroides odoratus isolates and antimicrobial susceptibility studies

The genus Myroides comprises several species of Gram-negative, non-motile, and non-fermenting bacteria, which have been regarded as non-pathogenic for decades. Multiple recent reports, however, underscore the pathogenic potential that Myroides sp. possesses for humans. These bacteria seem to be resistant to a wide range of antibiotics (including ß-lactams and aminoglycosides). Therefore, treatment options are limited. Knowledge of antimicrobial resistance, however, is based on only one meaningful comprehensive study and on data published from case reports. This lack of data motivated us to test 59 strains from our Myroides collection (43 M. odoratimimus and 16 M. odoratus) for resistance against 20 commonly used antibiotics. We also performed molecular analyses to reveal whether our bacteria harbor the genus-specific M. odoratimimus metallo-ß-lactamase (MUS-1) or the M. odoratus metallo ß-lactamase (TUS-1), and other ß-lactamases, which may provide an explanation for the extended antimicrobial resistance.

Nascent Genomic Evolution and Allopatric Speciation of Myroides profundi D25 in Its Transition from Land to Ocean

A large amount of bacterial biomass is transferred from land to ocean annually. Most transferred bacteria should not survive, but undoubtedly some do. It is unclear what mechanisms these bacteria use in order to survive and even thrive in a new marine environment. Myroides profundi D25^T, a member of the Bacteroidetes phylum, was isolated from deep-sea sediment of the southern Okinawa Trough near the China mainland and had high genomic sequence identity to and synteny with the human opportunistic pathogen Myroides odoratimimus. Phylogenetic and physiological analyses suggested that M. profundi recently transitioned from land to the ocean. This provided an opportunity to explore how a bacterial genome evolved to survive in a novel environment. Changes in the transcriptome were evaluated when both species were cultured under low-salinity conditions and then transferred to high-salinity conditions. Comparative genomic and transcriptomic analyses showed that M. profundi altered transcription regulation in the early stages of survival. In these stages, vertically inherited genes played a key role in the survival of M. profundi. The contribution of M. profundi unique genes, some possibly acquired by horizontal gene transfer (HGT), appeared relatively small, and expression levels of unique genes were diminished under the high-salinity conditions. We postulate that HGT genes might play an important role in longer-term adaptation. These results suggested that some human pathogens might have the ability to survive in and adapt to the marine environment, which may have important implications for public health control in coastal regions.

Horizontal gene transfer (HGT) is considered to be important for bacteria to adapt to a different microhabitat. However, our results showed that vertically inherited genes might play more important roles than HGT genes in the nascent adaptation to the marine environment in the bacterium Myroides profundi, which has recently been transferred from land to ocean. M. profundi unique genes had low expression levels and were less regulated under high-salinity conditions, indicating that the contribution of HGT genes to survival of this bacterium under marine high-salinity conditions was limited. In the early adaptation stages, M. profundi apparently survived and adapted mainly by regulating the expression of inherited core genes. These results may explain in part why human pathogens can easily be detected in marine environments.

Myroides indicus sp. nov., isolated from garden soil

A novel aerobic, non-motile, rod-shaped, catalase- and oxidase-positive bacterial strain, designated UKS3T, was isolated from garden soil, and subjected to polyphasic taxonomic analysis. Strain UKS3T formed whitish, viscous colonies on nutrient agar and was Gram-staining negative. Phylogenetic analysis, based on 16S rRNA gene sequence, showed that maximum pairwise similarity occurs with representatives of the genus Myroides. The most closely related species include Myroides marinus JS-08T (92.7 % sequence similarity), Myroides phaeus MY15T (92.7 %), Myroides odoratus DSM 2801T (91.5 %) and Myroides odoratimimus CCUG 39352T (91.4 %). Strain UKS3T contained menaquinone-6 (MK-6) as the major respiratory quinone and iso-C15 : 0 (40.2 %), anteiso-C15 : 0 (9.4 %) and iso-C17 : 0 3-OH (8.5 %) as major fatty acids. Phosphatidylethanolamine, phospholipids and three aminolipids were the major polar lipids. The DNA G+C content of strain UKS3T was 36.8 ± 2.0 mol%. On the basis of phenotypic, chemotaxonomic and molecular analysis, strain UKS3T represents a novel species of the genus Myroides, for which the name Myroides indicus sp. nov., is proposed. The type strain is UKS3T ( = DSM 28213T = NCIM 5555T ).

Comparison of VITEK2, MALDI-TOF MS, and 16S rDNA sequencing for identification of Myroides odoratus and Myroides odoratimimus

The genus Myroides comprises the 2 medically relevant species Myroides odoratus and Myroides odoratimimus that are rare opportunistic pathogens and cause infections in immunocompromised patients. A fast identification of Myroides is of importance because these bacterial strains show multiple resistance against antibiotics and therefore limit treatment options. They are associated, for instance, with urinary tract infections, sepsis, meningitis, pneumonia, and infectious cellulitis. Since more and more Myroides spp. are being described, additional potentially pathogenic bacteria may be identified in the future demanding the need for fast and reliable identification methods at species level. However, to date, only molecular approaches meet these demands. In this study, we, therefore, attempt to define an appropriate method other than DNA fingerprinting that will permit a comparable efficacy and, possibly, a more economical strain identification. For this purpose, we compared 2 widely used automated diagnostic systems (VITEK 2 [bioMérieux, Nürtingen, Germany] and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS) [Bruker Daltonics, Bremen, Germany]) and correlated the results to 16S rDNA sequencing data. In total, we analyzed 22 strains collected in the course of routine diagnostics. In this study, we demonstrate that VITEK 2 reliably identifies the genus Myroides but cannot differentiate between M. odoratimimus and M. odoratus. In contrast to this, both MALDI-TOF MS and 16S rDNA sequencing efficiently distinguish between the 2 species.