Phylogenetic Relationships of a Distinct Species of Globodera from Portugal and Two Punctodera Species

Evolutionary relationships based on ribosomal DNA (rDNA) sequence data for a previously unknown species of Globodera from Portugal, Punctodera chalcoensis from Mexico, and P. punctata from Estonia, plus previously published sequences, support the following relationships: (((Cactodera weissi, G. artemisiae, C. milleri), ((G. sp. Bouro, G. sp. Canha, G. sp. Ladoeiro), ((G. pallida, G. rostochiensis), (P. chalcoensis, P. punctata)))), Heterodera avenae). Globodera sp. from Portugal, which can be confused with potato cyst nematodes by phytosanitary services when the identification is based only on morphological characters, is clearly different based on our molecular data. In addition, the rDNA data show the Globodera sp. to be only distantly related to other European Globodera species that parasitize Asteraceae. Punctodera chalcoensis and P. punctata form a sister clade to the G. pallida + G. rostochiensis clade.     

Multilocus sequence analysis of putative Vibrio mediterranei strains and description of Vibrio thalassae sp. nov.

A multilocus sequence analysis based on partial gyrB, mreB, rpoD and pyrH genes was undertaken with 61 putative Vibrio mediterranei/V. shilonii strains from different hosts (mussels, oysters, clams, coral, fish and plankton) or habitat (seawater and sediment) and geographical origins (Mediterranean, Atlantic and Pacific). A consistent grouping was obtained with individual and concatenated gene sequences, and the clade, comprising 54 strains, was split into three subclades by all methods: subclade A (40 strains, including AK1, the former type strain of Vibrio shilonii), subclade B (8 strains) corresponding to the species V. mediterranei, and subclade C (six strains) representing a new species, V. thalassae sp. nov., with strain MD16^T (=CECT 8203^T = KCTC 32373^T) as the proposed type strain.     

Salinarubrum litoreum gen. nov., sp. nov.: a new member of the family Halobacteriaceae isolated from Chinese marine solar salterns

Three halophilic archaeal strains, XD46^T, YJ-63-S1 and ZS-1-H, were isolated from three Chinese marine solar salterns. All were observed to have pleomorphic cells that lysed in distilled water, stained Gram-negative and formed red-pigmented colonies. They were found to grow optimally at 37 °C, at pH 7.0 and in the presence of 2.6 M NaCl and 0.05 M Mg²⁺. The major polar lipids were identified as those typical for members of the Halobacteriaceae but also included major glycolipids chromatographically identical to sulfated mannosyl glucosyl diether (S-DGD-1), mannosyl glucosyl diether (DGD-1) and two unidentified ones. The 16S rRNA gene sequences of the three strains were 99.8–100 % identical, showing most similarity to sequences of members of the family Halobacteriaceae, and clustering together as a distinct clade in phylogenetic tree reconstructions. The rpoB′ gene similarities between the three strains were 98.7–100 % and lower to the sequences of other halobacteria. Their DNA G+C contents were determined to be 65.1–65.5 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strains XD46^T (=CGMCC 1.12237^T = JCM 18649^T), YJ-63-S1 (=CGMCC 1.12574) and ZS-1-H (=CGMCC 1.12544) represent a novel species in a new genus within the family Halobacteriaceae, for which the name Salinarubrum litoreum gen. nov., sp. nov. is proposed.     

Vibrio gallaecicus sp. nov. isolated from cultured clams in north-western Spain

A group of three motile facultative anaerobic marine bacteria were isolated from cultured Manila clams (Ruditapes philippinarum) in Galicia, north-western Spain. The strains were characterized phenotypically and genotypically. Phylogenetic analysis of the 16S rRNA gene and four housekeeping genes, RNA polymerase α-chain (rpoA), RecA protein (recA), the α-subunit of bacterial ATP synthase (atpA) and the uridine monophosphate (UMP) kinase (pyrH), indicated that these strains were closely related to the Vibrio splendidus clade. The amplified fragment length polymorphism (AFLP) fingerprints, DNA–DNA hybridizations and phylogenies of the housekeeping and 16S rRNA gene sequences showed that the three strains represented a different species from all currently described vibrios. The new species could be differentiated from its nearest neighbours on the basis of several phenotypic features. The three strains are therefore a novel species within the genus Vibrio, for which the name Vibrio gallaecicus is proposed, with the type strain being VB 8.9^T(=CECT 7244^T=LMG 24045^T).     

Halogranum salarium sp. nov., a halophilic archaeon isolated from sea salt

Three halophilic archaea, strains B-1^T, B-3 and B-4, were isolated from evaporitic salt crystals from Namhae, Korea. Cells of the strains were Gram-stain-negative, motile and pleomorphic, and colonies were red-pigmented. The three isolates had identical 16S rRNA gene sequences and formed a tight phylogenetic clade with Halogranum rubrum RO2-11^T in the genus Halogranum, showing 99.5% sequence similarity. The next most closely related species were Halogranum amylolyticum and Halogranum gelatinilyticum (97.4 and 96.3% similarity to the respective type strains). The phylogeny based on the full-length RNA polymerase subunit B′ gene (rpoB′) was in agreement with the 16S rRNA gene sequence analysis, but allowed better discrimination. DNA-DNA hybridization between a representative strain (B-1^T) and the type strains of Hgn. rubrum, Hgn. amylolyticum and Hgn. gelatinilyticum revealed less than 40% relatedness. Polar lipid analysis showed that the three isolates contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and three glycolipids. Combined genotypic and phenotypic data supported the conclusion that strains B-1^T, B-3 and B-4 represent a novel species of the genus Halogranum, for which the name Halogranum salarium sp. nov. is proposed. The type strain is B-1^T (=KCTC 4066^T = DSM 23171^T).     

Bradyrhizobium canariense and Bradyrhizobium japonicum are the two dominant rhizobium species in root nodules of lupin and serradella plants growing in Europe

Forty three Bradyrhizobium strains isolated in Poland from root nodules of lupin species (Lupinus albus, L. angustifolius and L. luteus), and pink serradella (Ornithopus sativus) were examined based on phylogenetic analyses of three housekeeping (atpD, glnII and recA) and nodulation (nodA) gene sequences. Additionally, seven strains originating from root-nodules of yellow serradella (O. compressus) from Asinara Island (Italy) were included in this study. Phylogenetic trees revealed that 15 serradella strains, including all yellow serradella isolates, and six lupin strains grouped in Bradyrhizobium canariense (BC) clade, whereas eight strains from pink serradella and 15 lupin strains were assigned to Bradyrhizobium japonicum (BJ1). Apparently, these species are the two dominant groups in soils of central Europe, in the nodules of lupin and serradella plants. Only three strains belonged to other chromosomal lineages: one formed a cluster that was sister to B. canariense, one strain grouped outside the branch formed by B. japonicum super-group, and one strain occupied a distant position in the genus Bradyrhizobium, clustering with strains of the Rhodopseudomonas genus. All strains in nodulation nodA gene tree grouped in a cluster referred to as Clade II, which is in line with earlier data on this clade dominance among Bradyrhizobium strains in Europe. The nodA tree revealed four well-supported subgroups within Clade II (II.1-II.4). Interestingly, all B. canariense strains clustered in subgroup II.1 whereas B. japonicum strains dominated subgroups II.2-II.4.     

Phylogeny of symbiotic cyanobacteria within the genus <Emphasis Type="Italic">Nostoc</Emphasis> based on 16S rDNA sequence analyses

A phylogenetic analysis of selected symbiotic Nostoc strain sequences and available database 16S rDNA sequences of both symbiotic and free-living cyanobacteria was carried out using maximum likelihood and Bayesian inference techniques. Most of the symbiotic strains fell into well separated clades. One clade consisted of a mixture of symbiotic and free-living isolates. This clade includes Nostoc sp. strain PCC 73102, the reference strain proposed for Nostoc punctiforme. A separate symbiotic clade with isolates exclusively from Gunnera species was also obtained, suggesting that not all symbiotic Nostoc species can be assigned to N. punctiforme. Moreover, isolates from Azolla filiculoides and one from Gunnera dentata were well nested within a clade comprising most of the Anabaena sequences. This result supports the affiliation of the Azolla isolates with the genus Anabaena and shows that strains within this genus can form symbioses with additional hosts. Furthermore, these symbiotic strains produced hormogonia, thereby verifying that hormogonia formation is not absent in Anabaena and cannot be used as a criterion to distinguish it from Nostoc.The GenBank accession numbers for the cyanobacterial 16S rRNA gene sequences determined in this study are AY742447-AY742454.     

A Suppression Subtractive Hybridization Approach Reveals Niche-Specific Genes That May Be Involved in Predator Avoidance in Marine Synechococcus Isolates

Picocyanobacteria of the genus Synechococcus are important contributors to marine primary production and are ubiquitous in the world's oceans. This genus is genetically diverse, and at least 10 discrete lineages or clades have been identified phylogenetically. However, little if anything is known about the genetic attributes which characterize particular lineages or are unique to specific strains. Here, we used a suppression subtractive hybridization (SSH) approach to identify strain- and clade-specific genes in two well-characterized laboratory strains, Synechococcus sp. strain WH8103 (clade III) and Synechococcus sp. strain WH7803 (clade V). Among the genes that were identified as potentially unique to each strain were genes encoding proteins that may be involved in specific predator avoidance, including a glycosyltransferase in strain WH8103 and a permease component of an ABC-type polysaccharide/polyol phosphate export system in WH7803. During this work the genome of one of these strains, WH7803, became available. This allowed assessment of the number of false-positive sequences (i.e., sequences present in the tester genome) present among the SSH-enriched sequences. We found that approximately 9% of the WH8103 sequences were potential false-positive sequences, which demonstrated that caution should be used when this technology is used to assess genomic differences in genetically similar bacterial strains.     

Cyanophycin Production in a Phycoerythrin-Containing Marine Synechococcus Strain of Unusual Phylogenetic Affinity

Thirty-two strains of phycoerythrin-containing marine picocyanobacteria were screened for the capacity to produce cyanophycin, a nitrogen storage compound synthesized by some, but not all, cyanobacteria. We found that one of these strains, Synechococcus sp. strain G2.1 from the Arabian Sea, was able to synthesize cyanophycin. The cyanophycin extracted from the cells was composed of roughly equimolar amounts of arginine and aspartate (29 and 35 mol%, respectively), as well as a small amount of glutamate (15 mol%). Phylogenetic analysis, based on partial 16S ribosomal DNA (rDNA) sequence data, showed that Synechococcus sp. strain G2.1 formed a well-supported clade with several strains of filamentous cyanobacteria. It was not closely related to several other well-studied marine picocyanobacteria, including Synechococcus strains PCC7002, WH7805, and WH8018 and Prochlorococcus sp. strain MIT9312. This is the first report of cyanophycin production in a phycoerythrin-containing strain of marine or halotolerant Synechococcus, and its discovery highlights the diversity of this ecologically important functional group.     

Bradyrhizobium aeschynomenes sp. nov., a root and stem nodule microsymbiont of Aeschynomene indica

Aeschynomene indica has a distinctive symbiosis with Bradyrhizobium in which nodulation is Nod factor-independent. In this study, we characterised three Gram-negative and rod-shaped strains (83002^T, 81013 and 83012) isolated from root nodules of Aeschynomene indica in Shandong Peninsula. The major cellular fatty acids of isolates were C_16:0, C_18:0, C_18:1 ω7c 11-methyl, summed feature 3 and summed feature 8. The major polar lipids were phosphatidylethanolamine (PE), aminolipids (AL) and phosphatidylcholine (PC). Phylogenetic analysis based on the 16S rRNA locus showed that they belonged to the Bradyrhizobium genus, and shared the highest similarity to the type strains Bradyrhizobium oligotrophicum S58^T and Bradyrhizobium denitrificans LMG 8443^T. As expected, analysis of concatenated sequences of six housekeeping genes (atpD, recA, glnII, dnaK, gyrB, and rpoB) and nifH gene proposed that these three strains formed a distinct clade within the genus Bradyrhizobium. The highest average nucleotide identity and DNA-DNA hybridization values of the three strains in comparison to the closest Bradyrhizobium species were 87.5% and 65.3%, respectively, which are far below the threshold of species delineation, and thus confirmed the three strains as a new species. The genome size of strain 83002^T is 7.52 Mbp, and the DNA G+C content is 65.42 mol%. Strain 83002^T (=KCTC 82266^T=MCCC 1K04775^T) was chosen as the type strain of the new species, for which the name Bradyrhizobium aeschynomenes sp. nov. was proposed.     

Tahibacter aquaticus gen. nov., sp. nov., a new gammaproteobacterium isolated from the drinking water supply system of Budapest (Hungary)

Three Gram-stain negative, aerobic, non-motile, non-spore-forming, rod-shaped bacterial strains, PYM5-11^T, RaM5-2 and PYM5-8, were isolated from the drinking water supply system of Budapest (Hungary) and their taxonomic positions were investigated by a polyphasic approach. All three strains grew optimally at 20-28 °C and pH 5-7 without NaCl. The G+C content of the DNA of the type strain was 65.4 mol%. On the basis of 16S rRNA gene sequence analysis, the isolates showed 94.5-94.9% sequence similarity to the type strain of Dokdonella koreensis and a similarity of 93.0-94.1% to the species of the genera Aquimonas and Arenimonas. The major isoprenoid quinone of the strains was ubiquinone Q-8. The predominant fatty acids were iso-C_15:0, iso-C_17:1ω9c, C_16:1ω7c, and C_16:0. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine, as well as several unidentified aminolipids and phospholipids were present. The 16S rRNA gene sequence analysis, the predominant fatty acids, the polar lipid composition, RiboPrint patterns, physiological and biochemical characteristics showed that the three strains were related but distinct from the type strains of the four recognized species of the genus Dokdonella, and indicated that the strains represented a new genus within the Gammaproteobacteria. The strain PYM5-11 (=DSM 21667^T=NCAIM B 02337^T) is proposed as the type strain of a new genus and species, designated as Tahibacter aquaticus gen. nov., sp. nov.     

Yarrowia porcina sp. nov. and Yarrowia bubula f.a. sp. nov., two yeast species from meat and river sediment

Eleven yeast strains representing two hitherto undescribed species were isolated from different kinds of meat samples in Hungary and one from the sediment of a tropical freshwater river in Southeastern Brazil. The analysis of the sequences of their large subunit rRNA gene D1/D2 domain and the internal transcribed spacer (ITS) regions placed the two new species in the Yarrowia clade. Some of the seven strains representing the first new species can mate and give rise to asci and form ascospores embedded in capsular material, which qualifies it as the third teleomorph species of the Yarrowia clade. The name Yarrowia porcina sp. nov. (type strain: NCAIM Y.02100^T = CBS 12935^T = NRRL Y-63669^T, allotype strain UFMG-RD131^A = CBS 12932^A) is proposed for this new yeast species, which, based on physiological characters, is indistinguishable from Yarrowia lipolytica and some other species of the genus. Considerable intraspecific variability was detected among the sequences of the large subunit rRNA gene D1/D2 domains of the seven strains. The variability among the D1/D2 sequences exceeded the divergence observed among the ITS sequences and in some cases more than 1 % substitution among the D1/D2 sequences was detected. The conspecificity of these strains was supported by the low (0–3 substitutions) sequence divergence among their ITS sequences, the result of a parsimony network analysis utilizing the concatenated ITS and D1/D2 sequences and also by the fingerprint patterns generated by microsatellite primed PCR. No ascospore formation was observed in the group of the other five strains representing the second new species. These strains shared identical D1/D2 and ITS sequences. Yarrowia bubula f.a., sp. nov. (type strain: NCAIM Y.01998^T = CBS 12934^T = NRRL Y-63668^T) is proposed to accommodate these strains.     

Indigenous Vibrio cholerae strains from a non-endemic region are pathogenic

Of the 200+ serogroups of Vibrio cholerae, only O1 or O139 strains are reported to cause cholera, and mostly in endemic regions. Cholera outbreaks elsewhere are considered to be via importation of pathogenic strains. Using established animal models, we show that diverse V. cholerae strains indigenous to a non-endemic environment (Sydney, Australia), including non-O1/O139 serogroup strains, are able to both colonize the intestine and result in fluid accumulation despite lacking virulence factors believed to be important. Most strains lacked the type three secretion system considered a mediator of diarrhoea in non-O1/O13 V. cholerae. Multi-locus sequence typing (MLST) showed that the Sydney isolates did not form a single clade and were distinct from O1/O139 toxigenic strains. There was no correlation between genetic relatedness and the profile of virulence-associated factors. Current analyses of diseases mediated by V. cholerae focus on endemic regions, with only those strains that possess particular virulence factors considered pathogenic. Our data suggest that factors other than those previously well described are of potential importance in influencing disease outbreaks.     

Classification of Streptomyces phylogroup pratensis (Doroghazi and Buckley, 2010) based on genetic and phenotypic evidence,and proposal of Streptomyces pratensis sp. nov.

The Streptomyces phylogroup pratensis (Doroghazi and Buckley, 2010) contains isolates obtained from grassy fields, as well as Streptomyces flavogriseus ATCC 33331 and strain CGMCC 4.1868. This latter strain was received as Streptomyces griseoplanus but was subsequently found to be mislabeled, and S. flavogriseus ATCC 33331 (=IAF-45-CD) was shown to be clearly distinct from the type strain S. flavogriseus ATCC 25452^T (=CGMCC 4.1884^T). In order to evaluate the taxonomic position of phylogroup pratensis further, sequences of the 16S rRNA gene and five protein-coding housekeeping genes (atpD, gyrB, recA, rpoB and trpB) were determined for six strains of the phylogroup and type strains of 19 related species, which were selected by a BLAST search based on the sequences of the phylogroup. The 16S rRNA gene sequences for the phylogroup were identical to those of eight species belonging to cluster I of the S. griseus clade. However, in all the individual protein-coding gene and MLSA phylogenies, the phylogroup strains without exception formed an obviously distinct cluster that could be equated with a new species status. The phylogenetic evidence for the new species assignment was also supported by corresponding DNA–DNA hybridization values and by phenotypic characteristics. It is therefore proposed that the phylogroup should be classified as Streptomyces pratensis sp. nov., and the type strain is ch24^T (=CGMCC 4.6829^T = NRRL B-24916^T).     

Monophyly of the family Desmoscolecidae (Nematoda,Demoscolecida) and Its Phylogenetic position inferred from 18S rDNA sequences

To infer the monophyletic origin and phylogenetic relationships of the order Desmoscolecida, a unique and puzzling group of mainly free-living marine nematodes, we newly determined nearly complete 18S rDNA sequences for six marine desmoscolecid nematodes belonging to four genera (Desmoscolex, Greeffiella, Tricoma and Paratricoma). Based on the present data and those of 72 nematode species previously reported, the first molecular phylogenetic analysis focusing on Desmoscolecida was done by using neighbor joining (NJ), maximum parsimony (MP), maximum likelihood (ML) and Bayesian inference (BI) methods. All four resultant trees consistently and strongly supported that the family Desmoscolecidae forms a monophyletic group with very high node confidence values. The monophyletic clade of desmocolecid nematodes was placed as a sister group of the clade including some members of Monhysterida and Araeolaimida, Cyartonema elegans (Cyartonematidae) and Terschellingia longicaudata (Linhomoeidae) in all the analyses. However, the present phylogenetic trees do not show any direct attraction between the families Desmoscolecidae and Cyartonematidae. Within the monophyletic clade of the family Desmoscolecidae in all of the present phylogenetic trees, there were consistently observed two distinct sub-groups which correspond to the subfamilies Desmoscolecinae [Greeffiella sp. + Desmoscolex sp.] and Tricominae [Paratricoma sp. + Tricoma sp].     

Rhizobium cremeum sp. nov., isolated from sewage and capable of acquisition of heavy metal and aromatic compounds resistance genes

Two strains of Rhizobia isolated from sewage collected from the Chinese Baijiu distillery were characterized using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains W15^T and W16 were grouped as a separate clade closely related to Rhizobium daejeonense L61^T (98.6%). Multilocus sequence analysis (MLSA) with three housekeeping genes (recA, glnII and rpoA) also showed that strains W15^T and W16 belonged to the genus Rhizobium. Average nucleotide identity and digital DNA–DNA hybridization values between genome sequences of strain W15^T and the closely related species ranged from 77.0% to 87.8% and from 23.9% to 30.9%. The DNA G + C content of strain W15^T was 61.6 mol%. Strain W15^T contained Q-10 as the major ubiquinone and the dominant fatty acids were summed feature 8 (C _18:1ω7c and/or C _18:1ω6c; 73.1%) and C_18:0 (7.6%). The main polar lipids are phosphatidylcholine, phosphatidylmethylethanolamine, phosphatidylethanolamine and phosphatidylglycerol. On the basis of the evidences presented in this study, strains W15^T and W16 represents a novel species of the genus Rhizobium, for which the name Rhizobium cremeum sp. nov. is proposed. The type strain is W15^T (= CGMCC 1.18731^T = KACC 22344^T).     

Veluticeps microspora sp. nov. and V. ambigua new to Asia with a preliminary phylogenetic study on the genus

Veluticeps microspora sp. nov. and V. ambigua new to Asia are described and illustrated based on morphological and molecular characters. V. microspora was collected from Yunnan Province, southwestern China, and is characterized by its special anatomical structure (without tomentum, cutis, and subiculum), simple septate hyphae, and small basidiospores. V. ambigua was collected from Jilin Province, northeastern China, and is reported in Asia for the first time. The molecular phylogeny of Veluticeps was preliminarily studied based on the analysis of ITS sequences from 18 species of Gloeophyllales. Two distinct clades of Veluticeps were formed in the phylogenetic tree. While V. microspora and V. ambigua clustered together to form a strongly supported clade, V. abietina, V. fimbriata, and V. berkeleyi grouped with Chaetodermella luna to form another clade.     

Ogataea kanchanaburiensis sp. nov. and Ogataea wangdongensis sp. nov., two novel methylotrophic yeast species from phylloplane in Thailand

Three strains (KM03^T, KM13 ^T and KM15) representing two novel methylotrophic yeast species were isolated from the external surface of plant leaves, which were collected from Kanchanaburi province, Thailand, by three-consecutive enrichments in methanol broth. Strain KM03^T was isolated from phylloplane of a mango tree (Mangifera indica) and two strains, KM13^T and KM15, were obtained from phylloplane of different wine grapes (Vitis vinifera). The sequences of the D1/D2 region of the large subunit (LSU) rRNA gene of the two strains (KM13^T and KM15) were identical and differed markedly from that of strain KM03^T. In terms of pairwise sequence similarity of the D1/D2 region the closest species to the strains KM13^T and KM15 were Candida suzukii (CBS 9253^T) and Candida nitratophila (CBS 2027^T) but with 2.1 % nucleotide substitutions. Strain KM03^T differed from Ogataea wickerhamii (CBS 4307^T), its closest relative, by 2.3 % nucleotide substitutions. Phylogenetic analysis based on the D1/D2 sequences placed the three strains in the Ogataea clade. On the basis of morphological, biochemical, physiological and chemotaxonomic characteristics, the sequence analyses of the D1/D2 and the internal transcribed spacer (ITS) regions of the nuclear ribosomal RNA gene (nrRNA) operon, the three strains represent two novel Ogataea species although formation of ascospores was not observed. Ogataea kanchanaburiensis sp. nov. is proposed for strain KM03^T (=BCC 47626^T = NBRC 108603^T = CBS 12673^T). Two strains, KM13^T and KM15, were assigned to Ogataea wangdongensis sp. nov. (type strain KM13^T = BCC 42664^T = NBRC 107778^T = CBS 12674^T). GenBank/EMBL/DDBJ accession numbers for the sequences of the D1/D2 and the ITS regions of O. kanchanaburiensis KM03^T are AB734090 and AB734093, respectively, of O. wangdongensis KM13^T are AB734091 and AB734094, respectively, and of O. wangdongensis KM15 are AB734092 and AB734095, respectively.     

Adhesion of marine cryptic Escherichia isolates to human intestinal epithelial cells

Five distinct cryptic lineages (clades I–V) have recently been recognized in the Escherichia genus. The five clades encompass strains that are phenotypically and taxonomically indistinguishable from Escherichia coli sensu stricto; however, scant data are available on their ecology, virulence and pathogenic properties. In this study 20 cryptic E. coli strains isolated from marine sediments were investigated to gain insights into their virulence characteristics and genetic traits. The ability to adhere to intestinal cells was highest among clade V strains, which also harbored the genes involved in gut colonization as well as the genes (pduC and eut operon) typically found in environmentally adapted E. coli strains. The pduC gene was significantly associated with clade V. Multilocus sequence typing of three representative clade V isolates revealed new sequence types (STs) and showed that the strains shared two allelic loci (adk 51 and recA 37). Our findings suggest that cryptic Escherichia lineages are common in coastal marine sediments and that this habitat may be suitable for their growth and persistence outside the host. On the other hand, detection in clade V strains of a gene repertoire and adhesion properties similar to those of intestinal pathogenic strains could indicate their potential virulence. It could be argued that there is a dual nature of cryptic clade V strains, where the ability to survive and persist in a secondary habitat does not involve the loss of the host-associated lifestyle. Clade V could be a group of closely related, environmentally adapted E. coli strains.