Persistence of antibiotic resistance from animal agricultural effluents to surface water revealed by genome-centric metagenomics.

Concerns about antibiotic resistance genes (ARGs) released from wastewaters of livestock or fish farming into the natural environment are increasing, but studies on unculturable bacteria related to the dissemination of antibiotic resistance are limited. Here, we reconstructed 1100 metagenome-assembled genomes (MAGs) to assess the impact of microbial antibiotic resistome and mobilome in wastewaters discharged to Korean rivers. Our results indicate that ARGs harbored in the MAGs were disseminated from wastewater effluents into downstream rivers. Moreover, it was found that ARGs are more commonly co-localized with mobile genetic elements (MGEs) in agricultural wastewater than in river water. Among the effluent-derived phyla, uncultured members of the superphylum Patescibacteria possessed a high number of MGEs, along with co-localized ARGs. Our findings suggest that members of the Patesibacteria are a potential vector for propagating ARGs into the environmental community. Therefore, we propose that the dissemination of ARGs by uncultured bacteria should be further investigated in multiple environments.

A Two-Step Real-Time PCR Method To Identify Mycobacterium tuberculosis Infections and Six Dominant Nontuberculous Mycobacterial Infections from Clinical Specimens.

Tuberculosis (TB) is an ongoing threat to public health, and furthermore, the incidence of infections by nontuberculous mycobacteria (NTM), whose symptoms are not distinguishable from TB, is increasing globally, thus indicating a need for accurate diagnostics for patients with suspected mycobacterial infections. Such diagnostic strategies need to include two steps, (i) detecting the mycobacterial infections and, if the case is an NTM infection, (ii) identifying the causative NTM pathogen. To eliminate a false-positive TB diagnosis for a host vaccinated by the bacillus Calmette-Guérin (BCG) strain of Mycobacterium bovis, a new target specific for M. tuberculosis species was selected, together with the species-specific targets for the six dominant NTM species of clinical importance, i.e., M. intracellulare, M. avium, M. kansasii, M. massiliense, M. abscessus, and M. fortuitum. Using sets of primers and probes, a two-step real-time multiplex PCR method was designed. The diagnostic performance was assessed by using a total of 1,772 clinical specimens from patients with suspected TB or NTM infection. A total of 69.4% of M. tuberculosis and 28.8% of NTM infections were positive for the primary step of the real-time PCR corresponding to the culture within 10 weeks, and mycobacterial species of 75.5% of the NTM-positive cases were identified by the secondary step. The two-step method described herein presented promising results and similar diagnostic sensitivity and specificity to commercially available real-time PCR kits for detecting TB and NTM infections. The method also enabled the identification of mycobacterial species in three-quarters of NTM infection cases, thus providing a better treatment strategy. IMPORTANCE Tuberculosis (TB) is an ongoing threat to public health. In addition, infection by nontuberculous mycobacteria (NTM) is a nonnegligible issue for global public health, with increasing incidences. Since the antimicrobial treatment strategy needs to be differed by the causative pathogen, a rapid and accurate diagnostic method is necessary. In this study, we developed a two-step molecular diagnostic method using clinical specimens of TB and NTM infection-suspected patients. The diagnostic power of the new method using the novel target was similar to the widely used TB detection kit, and, among the NTM-positive specimens, three-quarters of the NTM species were able to be identified. This simple and powerful method will be useful as it is, and it could be applied easily to a point-of-care diagnostic apparatus for better application to patients, especially those living in developing countries.

Various strategies applied for the removal of emerging micropollutant sulfamethazine: a systematic review.

Pharmaceutical active drug(s) especially sulfamethazine (SMZ) is considered as one of the major emerging microcontaminants due its long-term existence in the environmental system and that can influence on the developmental of antibacterial resistance genes. Because of this region it has a great concern in the aquatic system. Moreover, the vast utilization of SMZ, excretion of undigested portion by animals and also through dumping or mishandling, SMZ is frequently detected in various samples (including water) of different places and its surroundings. Additionally, reports shown it has toxic effect against microalgae and mice. Thus, that can lead to several investigators, focusing on removal of SMZ alone or in combination of other drugs in wastewater treatment plants (WWTPs) either by abiotic and/or biotic treatment methods. The present review provides an overview of the toxic effect of SMZ and SMZ degradation/removal in abiotic and biotic processes. Finally, reveals the need of further implication of integrated treatments (including engineered biological mediators) to understand ideal biological approaches for the mineralization of SMZ.

Flavobacterium inviolabile sp. nov. isolated from stream water.

A Gram-stain-negative, rod-shaped, aerobic and non-motile bacterium, designated P2-65T, was isolated from Moonsan stream water in the Republic of Korea. The temperature, NaCl concentration and pH ranges for growth of strain P2-65T were 10-37 °C, 0.0-3.0% (w/v) and 6.5-8.5 with optimum growth at 25-30 °C, 0.0-1.0% and 7.0-7.5, respectively. Comparison of 16S rRNA gene sequence showed that strain P2-65T was closely related to Flavobacterium cauense (95.4%) and Flavobacterium cheniae (95.3%). The major fatty acids were iso-C15:0, iso C17:0 3-OH, summed feature 3 (C16:1ω7c and/or C16:1ω6c), summed feature 9 (iso-C17:1 ω9c and/or 10-methyl C16:0) and iso-C15:0 3-OH. The predominant respiratory quinone was menaquinone-6 (MK-6). The major polar lipids detected in the strain were phosphatidylethanolamine, one aminophospholipid, one unidentified aminolipid and one unidentified polar lipid. The G + C content of the genomic DNA was 39.7%. The average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values for strain P2-65T with closely related Flavobacterium species were below 74.8% and 20%, respectively. Based on polyphasic features, strain P2-65T is considered to represent a novel species of the genus Flavobacterium, for which the name Flavobacterium inviolabile sp. nov. is proposed. The type strain is P2-65T (= KCTC 62055T = NBRC 112953T).

Author Correction: Dimethyl disulfide exerts antifungal activity against Sclerotinia minor by damaging its membrane and induces systemic resistance in host plants.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Distribution and epidemiological relatedness of methicillin-resistant Staphylococcus aureus isolated from companion dogs, owners, and environments.

This study aimed to investigate the distribution and epidemiological relatedness of methicillin-resistant Staphylococcus aureus (MRSA) isolates from companion dogs, owners, and residential environments of 72 households. Sampling was performed twice from January to June 2018 and a total of 2,592 specimens were collected. The specimens collected from each household were streaked on CHROM agar S. aureus and the colonies grown on the medium were further identified using a mass spectrometry microbial identification system. Antimicrobial susceptibility testing, Panton-Valentine-Leukocidin (PVL) gene PCR, staphylococcal cassette chromosome mec (SCCmec) typing, Staphylococcus aureus Protein A (spa) typing, pulsed-field gel electrophoresis (PFGE), and multi-locus sequence typing (MLST) were conducted to evaluate the phenotypic and genotypic characteristics of the MRSA isolates. A total of 65 S. aureus strains (2.5%) were isolated and 49 (1.9%) of 65 strains were MRSA displaying cefoxitin-resistance with mecA carriage. MRSA strains were isolated from dogs (n=6, 9.2%), owners (n=27, 41.5%), and residential environments (n=16, 24.6%), respectively. Overall prevalence of non-duplicated MRSA was 16.7% (12/72 households) at household level. ST72-SCCmec IVc MRSA clones predominantly appeared in MRSA-positive families. Furthermore, PFGE analyses showed that ST72-SCCmec IVc-t324 is shared between dog owners and dogs. To our knowledge, this is the first study to report the sharing of ST72 MRSA between dogs and their owners.

Molecular Characterization of Fecal Extended-Spectrum ß-Lactamase- and AmpC ß-Lactamase-Producing Escherichia coli From Healthy Companion Animals and Cohabiting Humans in South Korea.

This study aimed to describe the distribution and characterization of fecal extended-spectrum ß-lactamase (ESBL)- and AmpC-producing Escherichia coli isolates from healthy companion animals and cohabiting humans. A total of 968 rectal swab samples from 340 participants, including healthy companion animals and cohabiting humans, were collected from 130 households in South Korea from 2018 to 2019. To determine the bacterial profiles of the participants, several experiments were performed as follows: antimicrobial susceptibility testing, PCR and direct sequencing for ESBL/AmpC production, PFGE, MLST, whole genome sequencing and qRT-PCR. A total of 24.9 and 21.5% of the E. coli isolates from healthy companion animals and cohabiting humans were ESBL/AmpC producers, respectively. The bla CTX-M- 14 gene was the most prevalent ESC resistance gene in both pets (n = 25/95, 26.3%) and humans (n = 44/126, 34.9%). The bla CMY- 2 gene was also largely detected in pets (n = 19, 20.0%). Overall, intrahousehold pet-human sharing of ESBL/AmpC E. coli isolates occurred in 4.8% of households, and the isolates were all CTX-M-14 producers. In particular, ten CMY-2-producing E. coli isolates from seven dogs and three humans in the different households belonged to the same pulsotype. The MIC values of cefoxitin and the transcription level in CMY-2-producing E. coli isolates were proportional to the bla CMY- 2 copy number on the chromosome. Our results showed that the clonal spread of fecal ESBL/AmpC-producing E. coli households' isolates between healthy companion animals and cohabiting humans was rare, but it could happen. In particular, E. coli ST405 isolates carrying multiple bla CMY- 2 genes on the chromosome was sporadically spread between companion animals and humans in South Korea.

Dimethyl disulfide exerts antifungal activity against Sclerotinia minor by damaging its membrane and induces systemic resistance in host plants.

Microbial volatile compounds (MVCs) significantly influence the growth of plants and phytopathogens. However, the practical application of MVCs at the field level is limited by the fact that the concentrations at which these compounds antagonize the pathogens are often toxic for the plants. In this study, we investigated the effect of dimethyl disulfide (DMDS), one of the MVCs produced by microorganisms, on the fitness of tomato plants and its fungicidal potential against a fungal phytopathogen, Sclerotinia minor. DMDS showed strong fungicidal and plant growth promoting activities with regard to the inhibition of mycelial growth, sclerotia formation, and germination, and reduction of disease symptoms in tomato plants infected with S. minor. DMDS exposure significantly upregulated the expression of genes related to growth and defense against the pathogen in tomato. Especially, the overexpression of PR1 and PR5 suggested the involvement of the salicylic acid pathway in the induction of systemic resistance. Several morphological and ultrastructural changes were observed in the cell membrane of S. minor and the expression of ergosterol biosynthesis gene was significantly downregulated, suggesting that DMDS damaged the membrane, thereby affecting the growth and pathogenicity of the fungus. In conclusion, the tripartite interaction studies among pathogenic fungus, DMDS, and tomato revealed that DMDS played roles in antagonizing pathogen as well as improving the growth and disease resistance of tomato. Our findings provide new insights into the potential of volatile DMDS as an effective tool against sclerotial rot disease.

Clonal Spread of Extended-Spectrum Cephalosporin-Resistant Enterobacteriaceae Between Companion Animals and Humans in South Korea.

Extended-spectrum cephalosporin (ESC)-resistant Enterobacteriaceae is an increasingly important problem in both human and veterinary medicine. The aims of this study were to describe a comparative molecular characterization of Enterobacteriaceae carrying ESC resistance genes, encoding extended-spectrum ß-lactamase (ESBL) and AmpC, isolated from human stool samples, rectal swabs from companion animals, and swabs from the environment of veterinarian hospitals in South Korea, and to examine their possible dissemination and transmission. The ESC resistance genes were identified by PCR and sequencing. Isolates with the predominant ESC resistance genes were assessed for their genetic relatedness by pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing. A total of 195 Escherichia coli and 41 Klebsiella pneumoniae isolates that exhibited ESC resistance were recovered on CHROMagar ESBL from human, companion animal, and the veterinary hospital environmental samples. In companion animals, most of the ESC resistance genes were bla CMY-2-like (26.4%), followed by bla CTX -M-55 (17.2%) and bla CTX-M-14 (16.1%), whereas bla CTX-M-15 (28.6%) was predominant in human samples. The epidemiological relatedness of isolates carrying ESC resistance genes, including 124 E. coli and 23 K. pneumoniae isolates carrying CMY-2-like, DHA-1-like, or/and CTX-M-type, were analyzed by PFGE. The pulsotypes of five E. coli isolates (three from dogs and two from humans) carrying bla CMY-2-like, which were attributed to sequence type 405, from different veterinary clinics showed >85% similarity. Our results indicate direct transmission and dissemination of ESC-resistant Enterobacteriaceae between humans and companion animals.

Flavobacterium sangjuense sp. nov. isolated from sediment.

A yellow-pigmented bacterial strain, GS03T, was isolated from sediment in a branch of the Nackdong River in Sangju, Korea. Cells were observed to be Gram-negative, aerobic and rod-shaped with gliding motility, and to be positive for catalase and oxidase. Growth was found to occur at 4-30 °C (optimum 25 °C), at pH 7.0-8.5 (optimum pH 7.5) and at NaCl 0% (optimum NaCl 0%, w/v). The major cellular fatty acids (> 10% of the total) were identified as iso C15:0, iso C15:1 G, C15:1ω6c, iso C15: 0 3-OH and iso C17: 0 3-OH. The major respiratory quinone was found to be menaquinone MK-6. The genome sequence of GS03T is 3.1 Mb with G+C content of 36.1 mol%. The major polar lipids of the isolate were identified as phosphatidylethanolamine, three unidentified aminolipids, two unidentified phospholipids, an unidentified lipid and an unidentified aminophospholipid. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain GS03T clusters with Flavobacterium paronense KNUS1TT, with similarity of 96.8%. The phenotypic, phylogenetic, and chemotaxonomic characteristics indicate that strain GS03T represents a novel species of the genus Flavobacterium, for which the name Flavobacterium sangjuense sp. nov. is proposed. The type strain is GS03T (= FBCC 502459T = KCTC 62568T = JCM 32764T).

Ephemeroptericola cinctiostellae gen. nov., sp. nov., isolated from gut of an aquatic insect.

A Gram-stain-negative, catalase- and oxidase-positive, non-motile bacterium, designated F02T, was isolated from of gut of Cincticostellalevanidovae (Tshernova). Growth occurred at a temperature range of 4-30 °C, at pH 6-9 and in the presence of 0-0.5 % (w/v) NaCl. Phylogenetic analysis demonstrated that the 16S rRNA gene sequence of strain F02T shared the highest similarity to that of the type strain of Hydromonas duriensis A2P5T (96.82 %). The major isoprenoid quinone was Q-8. The polar lipids were diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The major cellular fatty acids were summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and iso-C13 : 0 3-OH. The polyamines were cadaverine and putrescine. Combined data from phylogenetic, phenotypic and chemotaxonomic analyses demonstrated that strain F02T represents a novel genus and species, for which the name Ephemeroptericolacinctiostellae gen. nov., sp. nov. is proposed. The type strain of Ephemeroptericola cinctiostellae gen. nov., sp. nov. is F02T (=FBCC 500047T=KCTC 62567T=JCM 32722T).

First Detection of New Delhi Metallo-ß-Lactamase-5-Producing Escherichia coli from Companion Animals in Korea.

The gene for New Delhi metallo-ß-lactamase-5 (NDM-5) in Escherichia coli has been identified in many countries mainly from human clinical specimens. The isolates carrying this gene are even more rarely isolated from companion animals. In this study, four carbapenem-resistant isolates were recovered from four dogs in Korea. All isolates carried blaNDM-5 and exhibited resistance to meropenem and imipenem, and were susceptible to colistin. Epidemiological analysis showed that all four isolates were sequence type 410 (ST410) and shared 99% similarity as determined by pulsed-field gel electrophoresis analysis. Among the four isolates, the Z0117EC0033 strain was randomly selected for whole-genome sequencing, composed of a 4.7Mb circularized chromosome carrying the CMY-2 gene and two plasmids. The first plasmid of the IncFIB type had 83 coding sequences (CDS) in ca. 74 kb. The second smaller plasmid of the IncX3 type had 57 CDS and carried only the blaNDM-5 gene in ca. 46 kb. The plasmid structures were highly similar (> 99%) to those of the NDM-5 human-like IncX3 plasmid. This is the first report of carbapenemase-producing Enterobacteriaceae from companion animals in Korea. The human-like blaNDM-5 IncX3 plasmid identified in this study suggests a potential transmission route of the NDM-5 plasmid between humans and companion animals.

Sphingobacterium praediipecoris sp. nov. isolated from effluent of a dairy manure treatment plant.

A novel Gram-reaction-negative, rod-shaped, non-motile bacterium, designated as strain G2-10T was isolated from effluent of a dairy manure treatment plant. Growth occurred at 20-40 °C (optimum at 25-30 °C), pH 7.0-8.0 (optimum at pH 7.0). The range of NaCl concentration for growth was between 0% and 3% (w/v) (optimum 0-1%, w/v). Comparison of 16S rRNA gene sequence indicated that strain G2-10T was moderately related to the type strains of Sphingobacterium nematocida M-SX103T and Sphingobacterium suaedae T47T with a pair-wise sequence similarity of 94.3% and 94.0%, respectively. The major fatty acid constituents of strain G2-10T were identified as iso-C15:0 (37.6%), summed feature 3 (consisting of C16:1ω7c and/or C16:1ω6c, 29.6%) and iso-C17:0 3-OH (15.2%). Phosphatidylethanolamine was the major polar lipids of strain G2-10T. Sphingophospholipids were present. The isoprenoid quinone was composed of only MK-7. The DNA G + C content of strain G2-10T was found to be 42.5 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain G2-10T represents a novel species within the genus Sphingobacterium, for which the name Sphingobacterium praediipecoris is proposed. The type strain is G2-10T (= KCTC 52880T = NBRC 112848T).

Flavobacterium amnigenum sp. nov. Isolated from a River.

A yellowish, flexirubin-pigment-producing strain I3-3T was isolated from river water in Iksan, the Republic of Korea. The strain was gram-negative, aerobic, non-motile, showed catalase and oxidase activities, and could grow at a temperature range of 10-35°C, pH 5.0-10 and 0-2.0% (w/v) of NaCl. The major fatty acids were iso-C15:0, iso-C17:0 3-OH and summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c). The isolate contained phosphatidylethanolamine, one aminolipid, and two unidentified lipids as the major polar lipids. Menaquinone-6 (MK6) was the major respiratory quinone. The G+C content of the genomic DNA of strain I3-3T was 35.6%. Comparison of the 16S rRNA gene sequence with the sequences of the closely related type strains showed highest sequence similarity of 96.95% and 96.93% to Flavobacterium nitrogenifigens NXU-44T and Flavobacterium compostarboris 15C3T, respectively. Based on phenotypic and phylogenetic distinctiveness, strain I3-3T is considered as a member of novel species within the genus Flavobacterium, for which Flavobacterium amnigenum sp. nov. is proposed. The type strain is I3-3T (=KCTC 52884T =NBRC 112871T).

VOCs-mediated hormonal signaling and crosstalk with plant growth promoting microbes.

In the natural environment, plants communicate with various microorganisms (pathogenic or beneficial) and exhibit differential responses. In recent years, research on microbial volatile compounds (MVCs) has revealed them to be simple, effective and efficient groups of compounds that modulate plant growth and developmental processes. They also interfere with the signaling process. Different MVCs have been shown to promote plant growth via improved photosynthesis rates, increased plant resistance to pathogens, activated phytohormone signaling pathways, or, in some cases, inhibit plant growth, leading to death. Regardless of these exhibited roles, the molecules responsible, the underlying mechanisms, and induced specific metabolic/molecular changes are not fully understood. Here, we review current knowledge on the effects of MVCs on plants, with particular emphasis on their modulation of the salicylic acid, jasmonic acid/ethylene, and auxin signaling pathways. Additionally, opportunities for further research and potential practical applications presented.

Soonwooa purpurea sp. nov., isolated from a fresh water river.

A pale-brown-coloured, rod-shaped, non-motile, and Gram-reaction-negative bacterium, strain I54T, was isolated from a water sample of a freshwater river in Iksan, Republic of Korea. The phylogenetic affiliation based on 16S rRNA gene sequence analysis showed that strain I54T belonged to the genus Soonwooa of the family Flavobacteriaceae with a sequence similarity of 97.5 % to Soonwooa buanensis HM0024T. The major fatty acids (>5 %) of strain I54T were iso-C15 : 0, anteiso-C15 : 0, summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and iso-C17 : 0 3-OH. Phosphatidylethanolamine, one aminolipid and two unknown lipids were the major polar lipids. The G+C content of the genomic DNA was 34.2 (±0.3)mol% and MK6 was the sole respiratory quinone. On the basis of its molecular and phenotypic characteristics, strain I54T represents a novel species in the genus Soonwooa, for which the name Soonwooapurpurea sp. nov. is proposed. The type strain is I54T (=KCTC 52722T=JCM 31880T).

Isothermal assay targeting class 1 integrase gene for environmental surveillance of antibiotic resistance markers.

Antimicrobial resistance genes (ARGs) present in the environment pose a risk to human health due to potential for transfer to human pathogens. Surveillance is an integral part of mitigating environmental dissemination. Quantification of the mobile genetic element class 1 integron-integrase gene (intI1) has been proposed as a surrogate to measuring multiple ARGs. Measurement of such indicator genes can be further simplified by adopting emerging nucleic acids methods such as loop mediated isothermal amplification (LAMP). In this study, LAMP assays were designed and tested for estimating relative abundance of the intI1 gene, which included design of a universal bacteria 16S rRNA gene assay. Following validation of sensitivity and specificity with known bacterial strains, the assays were tested using DNA extracted from river and lake samples. Results showed a significant Pearson correlation (R2 = 0.8) between the intI1 gene LAMP assay and ARG relative abundance (measured via qPCR). To demonstrate the ruggedness of the LAMP assays, experiments were also run in the hands of relatively "untrained" personnel by volunteer undergraduate students at a local community college using a hand-held real-time DNA analysis device - Gene-Z. Overall, results support use of the intI1 gene as an indicator of ARGs and the LAMP assays exhibit the opportunity for volunteers to monitor environmental samples for anthropogenic pollution outside of a specialized laboratory.

Chitinimonas naiadis sp. nov., Isolated from a Freshwater River.

A rod shaped, aerobic, Gram-stain-negative, and motile bacterium, strain AR2T, was isolated from a water sample of Yeongsan river, Republic of Korea. Strain AR2T clustered closely with the members of the genus Chitinimonas and showed the highest 16S rRNA gene sequence similarity with Chitinimonas prasina LY03T (96.4%), Chitinimonas viridis HMD2169T (96.4%), Chitinimonas taiwanensis cfT (96.2%), and Chitinimonas koreensis R2A43-10T (94.2%). The predominant fatty acids of strain AR2T were identified to be summed feature 3 (comprising C16:1ω7c and/or C16:1ω6c), C16:0, and C10:03-OH. Diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine were found to be the major polar lipids. The genomic DNA G+C content was 60.4 mol%. Based on the polyphasic characterization, the isolated strain AR2T is described as a representative of a novel species in the genus Chitinimonas, for which the name Chitinimonas naiadis sp. nov. (type strain =AR2T =KCTC 42755T =JCM 31504T) is proposed.

Reclassification of Aeromonas sharmana to a new genus as Pseudaeromonas sharmana gen. nov., comb. nov., and description of Pseudaeromonas pectinilytica sp. nov. isolated from a freshwater stream.

A Gram-reaction-negative, rod-shaped, facultatively anaerobic, motile bacterium, designated strain AR1T, was isolated from a freshwater stream in Jeonju, South Korea. Strain AR1T showed highest 16S rRNA gene sequence similarity (96.83 %) and also formed a separate clade with Aeromonas sharmana GPTSA-6T in the phylogenetic tree reconstructed among the members of the family Aeromonadaceae. Major cellular fatty acids are summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and C16: 0. Diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol are the predominant polar lipids. The genomic DNA G+C content was found to be 54.7 mol%. However, earlier studies on 16S rRNA gene, gyrB, rpoD and universal target region of cpn60 sequences of the members of the genus Aeromonas recommended the transfer of Aeromonas sharmana to a new genus. Hence, based on the comparative polyphasic data obtained during the present study and also on the previous recommendations, it is proposed that Aeromonas sharmana be transferred to a novel genus as Pseudaeromonas sharmana gen. nov., comb. nov. with strain GPTSA-6T (=DSM 17445T=MTCC 7090T=CIP 109378T=CCUG 54939T) as the type strain of the type species of the genus. Also, it is proposed that strain AR1T be designated as a representative of a novel species of this new genus, namely Pseudaeromonas pectinilytica sp. nov. The type strain is AR1T (=KCTC 42754T=JCM 31503T).

Microbial Community Composition in the Marine Sediments of Jeju Island: Next-Generation Sequencing Surveys.

Marine sediments are a microbial biosphere with an unknown physiology, and the sediments harbor numerous distinct phylogenetic lineages of Bacteria and Archaea that are at present uncultured. In this study, the structure of the archaeal and bacterial communities was investigated in the surface and subsurface sediments of Jeju Island using a next-generation sequencing method. The microbial communities in the surface sediments were distinct from those in the subsurface sediments; the relative abundance of sequences for Thaumarchaeota, Actinobacteria, Bacteroides, Alphaproteobacteria, and Gammaproteobacteria were higher in the surface than subsurface sediments, whereas the sequences for Euryarchaeota, Acidobacteria, Firmicutes, and Deltaproteobacteria were relatively more abundant in the subsurface than surface sediments. This study presents detailed characterization of the spatial distribution of benthic microbial communities of Jeju Island and provides fundamental information on the potential interactions mediated by microorganisms with the different biogeochemical cycles in coastal sediments.