Antibiotic resistance in shellfish and major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea.

Shellfish-growing areas in marine environments are affected by pollutants that mainly originate from land, including streams, domestic wastewater, and the effluents of wastewater treatment plants (WWTPs), which may function as reservoirs of antibiotic-resistant bacteria (ARB) and antibiotic-resistance genes (ARGs). The objective of this study was to identify the occurrence and distribution of antibiotic resistance at five oyster sampling sites and 11 major inland pollution sources in the drainage basin of Kamak Bay, Republic of Korea. Culture-based methods were used to estimate the diversity and abundance of antibiotic-resistant Escherichia coli strains isolated from oysters and major inland pollution sources. The percentages of ARB and multiple antibiotic resistance index values were significantly high in discharge water from small fishing villages without WWTPs. However, the percentages of antibiotic-resistant E. coli isolates from oysters were low, as there was no impact from major inland pollutants. Fourteen ARGs were also quantified from oysters and major inland pollution sources. Although most ARGs except for quinolones were widely distributed in domestic wastewater discharge and effluent from WWTPs, macrolide resistance genes (ermB and msrA) were detected mainly from oysters in Kamak Bay. This study will aid in tracking the sources of antibiotic contamination in shellfish to determine the correlation between shellfish and inland pollution sources.

Assessment of potential infectivity of human norovirus in the traditional Korean salted clam product "Jogaejeotgal" by floating electrode-dielectric barrier discharge plasma.

This study investigated the antiviral effects of floating electrode-dielectric barrier discharge (FE-DBD) plasma treatment (1.1 kV, 43 kHz, N2 1.5 m/s, 5-30 min) against human norovirus (HuNoV) GII.4 in Jogaejeotgal Infectivity was assessed using real-time quantitative-PCR (RT-qPCR) following treatment of samples with propidium monoazide (PMA) and sodium lauroyl sarcosinate (Sarkosyl). This study also investigated the effects of FE-DBD plasma treatment on Jogaejeotgal quality (assessed using pH value and Hunter colors). Following inoculation, the average titers of HuNoV GII.4 in Jogaejeotgal significantly (P < 0.05) decreased with increases in the FE-DBD plasma treatment time in both the non-PMA-treated and PMA + Sarkosyl-treated samples; in the non-PMA and PMA + Sarkosyl treated Jogaejeotgal, HuNoV GII.4 titers (log10 copy number/µL) were to: 3.16 and 2.95 (5 min), 2.90 and 2.48 (10 min), 2.82 and 2.40 (15 min), 2.58 and 2.26 (20 min), 2.48 and 2.06 (25 min), and 2.23 and 1.91 (30 min), respectively. The average titers of HuNoV demonstrated significant (P < 0.05) reductions of 0.35 log10 (55.3%) in PMA + Sarkosyl-treated samples compared with the non-PMA treated samples following exposure to 5-30 min of FE-DBD plasma. Reductions of >1-log for HuNoV in PMA + Sarkosyl- treated Jogaejeotgal required treatments of FE-DBD of 5-30 min. Using the first order kinetic model (R2 = 0.95), GII.4 decimal reduction time (D-value) resulting from FE-DBD plasma was 23.75 min. The pH and Hunter colors ("L", "a", and "b") were not significantly different (P > 0.05) between the untreated and FE-DBD plasma-treated Jogaejeotgal. Based on these results, the PMA + Sarkosyl/RT-qPCR method could be assessing HuNoV viability following 5-30 min treatment of FE-DBD plasma. Furthermore, may be an optimal treatment for Jogaejeotgal without altering the food quality (color and pH).

Virucidal Effects of Dielectric Barrier Discharge Plasma on Human Norovirus Infectivity in Fresh Oysters (Crassostrea gigas).

This study investigates the effects of dielectric barrier discharge (DBD) plasma treatment (1.1 kV, 43 kHz, N2 1.5 L/min, 10~60 min) on human norovirus (HuNoV) GII.4 infectivity in fresh oysters. HuNoV viability in oysters was assessed by using propidium monoazide (PMA) as a nucleic acid intercalating dye before performing a real-time reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Additionally, the impact of the DBD plasma treatment on pH and Hunter colors was assessed. When DBD plasma was treated for 60 min, the HuNoV genomic titer reduction without PMA pretreatment was negligible (<1 log copy number/µL), whereas when PMA treatment was used, HuNoV titer was reduced to >1 log copy number/µL in just 30 min. D1 and D2-value of HuNoV infectivity were calculated as 36.5 and 73.0 min of the DBD plasma treatment, respectively, using the first-order kinetics model (R2 = 0.98). The pH and Hunter colors were not significantly different (p > 0.05) between the untreated and DBD-plasma-treated oysters. The results suggest that PMA/RT-qPCR could help distinguish HuNoV infectivity without negatively affecting oyster quality following >30 min treatment with DBD plasma. Moreover, the inactivation kinetics of nonthermal DBD plasma against HuNoV in fresh oysters might provide basic information for oyster processing and distribution.

Level of contamination in the feces of several species at major inland pollution sources in the drainage basin of Yeoja Bay, Republic of Korea.

We assessed the levels of fecal contamination and the originating species of 12 major inland pollutants in the drainage basin of Yeoja Bay. The presence of the human-specific (HF183), ruminant-specific (BacR and Rum-2-Bac), pig-specific (Pig-Bac-2 and Pig-2-Bac), avian-specific (GFD), and gull-specific (Gull2) markers in water samples (n = 34) from 12 inland pollution sources around Yeoja Bay was analyzed. HF183 was detected in 97% of the water samples, and all major inland pollution sources were contaminated with human feces. BacR and Rum-2-Bac were detected in 94% and 11%, respectively, of the water samples. Pig-2-Bac was not detected in the inland pollution sources, but site L5 might be contaminated with swine feces. Gull2 was not detected, whereas GFD was detected in 26% of the water samples. This study highlights the utility of a MST toolbox approach for characterizing the water quality of inland pollution sources and identifying the feces producing species.

Fecal source tracking based on fecal coliform concentration and bacterial community structure in the Bong stream, Korea.

Fecal source tracking of the Bong stream, a representative inland pollutant around the drainage basin of Gangjin Bay (an area where shellfish are grown for export), was performed three times in four confluence areas with 13 sampling sites by analyzing fecal coliform concentrations and two types of bacterial community structures. Identification of the origin of major fecal pollution in the area that inflowed simultaneously via several branch streams was difficult using fecal source tracking based on fecal coliform concentration. Bacterial community analyses using high-throughput sequencing showed that the dominant groups in the entire bacterial community at the class level were Beta-, Gamma-, and Alpha-proteobacteria; Flavobacteriia; and Bacteroidia, and the most abundant groups in the Bacteroidales-specific community at the genus level were Prevotella and Bacteroides. Hierarchical clustering and Bray-Curtis dissimilarity analysis for fecal source tracking indicated that the Bacteroidales-specific community was superior in water environments compared with analysis of the entire bacterial community. Conversely, when the degree of fecal pollution in the sample was low, fecal source tracking based on the entire bacterial community was more reliable. These results suggest that fecal source tracking based on bacterial communities is a useful tool for identifying the origin of fecal pollution in a large stream and implementing systematic guidelines for the establishment of an effective management plan to reduce fecal pollution sources.

Microbial succession and metabolite changes during fermentation of dongchimi, traditional Korean watery kimchi.

Dongchimi, one of the most common types of watery kimchi in Korea, was prepared using radish and its pH values, microbial cell numbers, bacterial communities, and metabolites were monitored periodically to investigate the fermentation process of watery kimchi. The bacterial abundance increased quickly during the early fermentation period and the pH values concurrently decreased rapidly without any initial pH increase. After 15 days of fermentation, the bacterial abundance decreased rapidly with the increase of Saccharomyces abundance and then increased again with a decrease of Saccharomyces abundance after 40 days of fermentation, suggesting that bacteria and Saccharomyces have a direct antagonistic relationship. Finally, after 60 days of fermentation, a decrease in bacterial abundance and the growth of Candida were concurrently observed. Community analysis using pyrosequencing revealed that diverse genera such as Leuconostoc, Lactobacillus, Pseudomonas, Pantoea, and Weissella were present at initial fermentation (day 0), but Leuconostoc became predominant within only three days of fermentation and remained predominant until the end of fermentation (day 100). Metabolite analysis using (1)H NMR showed that the concentrations of free sugars (fructose and glucose) were very low during the early fermentation period, but their concentrations increased rapidly although lactate, mannitol, and acetate were produced. After 30 days of fermentation, quick consumption of free sugars and production of glycerol and ethanol were observed concurrently with the growth of Saccharomyces, levels of which might be considered for use as a potential indicator of dongchimi quality and fermentation time.

Microbial succession and metabolite changes during long-term storage of Kimchi.

Kimchi is often stored for a long period of time for a diet during the winter season because it is an essential side dish for Korean meals. In this study pH, abundance of bacteria and yeasts, bacterial communities, and metabolites were monitored periodically to investigate the fermentation process of kimchi for 120 d. Bacterial abundance increased quickly with a pH decrease after an initial pH increase during the early fermentation period. After 20 d, pH values became relatively stable and free sugars were maintained at relatively constant levels, indicating that kimchi fermentation by lactic acid bacteria (LAB) was almost completed. After that time, a decrease in bacterial abundance and a growth in Saccharomyces occurred concurrently with increased free sugar consumption and production of glycerol and ethanol. Finally, after 100 d, the growth of Candida was observed. Community analysis using pyrosequencing revealed that diverse LAB including Leuconostoc citreum, Leuconostoc holzapfelii, Lactococcus lactis, and Weissella soli were present during the early fermentation period, but the LAB community was quickly replaced with Lactobacillus sakei, Leuconostoc gasicomitatum, and Weissella koreensis as the fermentation progressed. Metabolite analysis using (1) H-NMR showed that organic acids (lactate, acetate, and succinate) as well as bioactive substances (mannitol and gamma-aminobutyric acid (GABA)) were produced during the kimchi fermentation, and Leuconostoc strains and Lactobacillus sakei were identified as the producers of mannitol and GABA, respectively.

Effects of red pepper powder on microbial communities and metabolites during kimchi fermentation.

To investigate the effects of red pepper powder on kimchi fermentation, Baechu (Chinese cabbage) and Mu (radish) kimchi, with and without red pepper powder, were prepared and their characteristics, including pH, colony-forming units (CFU), microbial communities, and metabolites, were periodically monitored for 40days. Measurements of pH and CFU showed that the lag phases of kimchi fermentation were clearly extended by the addition of red pepper powder. Microbial community analysis using a barcoded pyrosequencing analysis showed that the bacterial diversities in kimchi with red pepper powder decreased more slowly than kimchi without red pepper powder as kimchi fermentation progressed. The kimchi microbial communities were represented mainly by the genera Leuconostoc and Lactobacillus in all kimchi, and the abundance of Weissella was negligible in kimchi without red pepper powder. However, interestingly, kimchi with red pepper powder contained much higher proportions of Weissella than kimchi without red pepper powder, while the proportions of Leuconostoc and Lactobacillus were evidently lower in kimchi with red pepper powder compared to kimchi without red pepper powder. Metabolite analysis using a (1)H NMR technique also showed that the fermentation of kimchi with red pepper powder progressed a little more slowly than that of kimchi without red pepper powder. Principle component analysis using microbial communities and metabolites supported the finding that the addition of red pepper powder into kimchi resulted in the slowing of the kimchi fermentation process, especially during the early fermentation period and influenced the microbial succession and metabolite production during the kimchi fermentation processes.

Defluviimonas aestuarii sp. nov., a marine bacterium isolated from a tidal flat, and emended description of the genus Defluviimonas Foesel et al. 2011.

A novel Gram-staining-negative, strictly aerobic bacterium, designated BS14(T), was isolated from a marine tidal flat of the South Sea in Korea. Colonies were opaque, white, smooth and circular on marine agar. Cells were moderately halophilic, non-motile rods showing catalase- and oxidase-positive reactions. Growth of strain BS14(T) was observed at 5-40 °C (optimum: 30 °C), pH 6.5-9.5 (optimum: 7.0-7.5) and 0-10 % (w/v) NaCl (optimum: 1-1.5 %). The G+C content of the genomic DNA was 61.6 mol%. Strain BS14(T) contained ubiquinone-10 (Q-10) as the sole respiratory quinone and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C18 : 0 3-OH, C10 : 0 3-OH and C18 : 0 as the major fatty acids. The polar lipid pattern comprised phosphatidylethanolamine, diphosphatidylglycerol, an unidentified aminolipid, an unidentified phospholipid and an unidentified polar lipid. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain BS14(T) formed a tight phylogenetic lineage with Defluviimonas denitrificans D9-3(T) with a bootstrap value of 100 %. The 16S rRNA gene sequence similarity between strain BS14(T) and D. denitrificans D9-3(T) was 97.4 % and their DNA-DNA relatedness was 19.1 ± 3.6 %. Based on the phenotypic and genotypic studies, strain BS14(T) represents a novel species of the genus Defluviimonas, for which the name Defluviimonas aestuarii sp. nov. is proposed. The type strain is BS14(T) (= KACC 16442(T) = JCM 18630(T)). An emended description of the genus Defluviimonas Foesel et al. 2011 is also proposed.

Gramella aestuarii sp. nov., isolated from a tidal flat, and emended description of Gramella echinicola.

A Gram-staining-negative, yellow-pigmented, strictly aerobic bacterial strain motile by gliding, designated BS12(T), was isolated from a tidal flat at Boseong, Korea. Cells were moderately halotolerant, catalase- and oxidase-positive rods. Growth was observed at 5-40 °C (optimum, 25 °C), at pH 5.5-9.0 (optimum, pH 7.0-7.5) and in the presence of 1-11 % (w/v) NaCl (optimum, 2-4 %). The major cellular fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, iso-C17 : 1ω9c and anteiso-C15 : 0. The polar lipid pattern comprised phosphatidylethanolamine, four unidentified aminolipids and three unidentified lipids. The G+C content of the genomic DNA was 42.3 mol% and the only respiratory quinone was menaquinone 6. Phylogenetic inference based on 16S rRNA gene sequences showed that strain BS12(T) formed a tight phyletic lineage with members of the genus Gramella. Strain BS12(T) was most closely related to 'Gramella jeungdoensis' HMD3159 with sequence similarity of 97.5 %, but the DNA-DNA relatedness value between the two strains was only 22.1 ± 2.2 %. On the basis of phenotypic and molecular features, strain BS12(T) was shown to represent a novel species of the genus Gramella, for which the name Gramella aestuarii sp. nov. is proposed. The type strain is BS12(T) ( = KACC 16188(T) = JCM 17790(T)). An emended description of Gramella echinicola is also proposed.

Altererythrobacter gangjinensis sp. nov., a marine bacterium isolated from a tidal flat.

A Gram-stain-negative, ochre-pigmented, strictly aerobic bacterium, designated strain KJ7(T), was isolated from a tidal flat of the Gangjin bay in South Korea. Cells were halotolerant, non-motile, catalase- and oxidase-positive rods. Growth of strain KJ7(T) was observed at 5-35 °C (optimum, 25 °C), at pH 6.0-9.5 (optimum, pH 6.5-7.0) and in the presence of 0-9 % (w/v) NaCl (optimum, 2 %). The major cellular fatty acids were C18 : 1ω7c, C17 : 1ω6c, summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The polar lipid pattern indicated the presence of phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, a sphingoglycolipid, an unidentified phospholipid and two unidentified lipids. The G+C content of the genomic DNA was 60.2±0.9 mol% and the predominant respiratory quinone was Q-10. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain KJ7(T) formed a phyletic lineage distinct from other members of the genus Altererythrobacter and was most closely related to Altererythrobacter luteolus SW-109(T) and Altererythrobacter namhicola KYW48(T) (95.6 and 95.0 % 16S rRNA gene sequence similarity, respectively). On the basis of phenotypic, chemotaxonomic and molecular features, strain KJ7(T) represents a novel species of the genus Altererythrobacter, for which the name Altererythrobacter gangjinensis sp. nov. is proposed. The type strain is KJ7(T) ( = KACC 16190(T) = JCM 17802(T)).

Arenibacter hampyeongensis sp. nov., a marine bacterium isolated from a tidal flat.

A Gram-staining-negative, dark orange, strictly aerobic bacterium, designated strain HP12(T), was isolated from a tidal flat at Hampyeong in South Korea. Cells were moderately halotolerant, catalase- and oxidase-positive, non-motile rods. Growth was observed at 5-35 °C (optimum, 25 °C), at pH 6.0-8.5 (optimum, pH 7.0-7.5), and in the presence of 1-6 % (w/v) NaCl (optimum, 1-2 %). The major cellular fatty acids were summed feature 3 (C(16 : 1)ω7c and/or iso-C(15 : 0) 2-OH), iso-C(17 : 0) 3-OH, C(15 : 0), iso-C(15 : 1) G and iso-C(15 : 0). The polar lipid pattern indicated the presence of phosphatidylethanolamine and two unidentified lipids. The G+C content of the genomic DNA was 37.1 mol% and the predominant respiratory quinone was menaquinone-6. Phylogenetic analysis based on 16S rRNA gene sequences showed that the novel strain formed a tight phyletic lineage with members of the genus Arenibacter and was most closely related to Arenibacter palladensis KMM 3961(T), Arenibacter troitsensis KMM 3674(T) and Arenibacter echinorum KMM 6032(T), with 16S rRNA gene sequence similarities of 98.1 %, 98.0 % and 97.8 %, respectively. However, the DNA-DNA relatedness values between strain HP12(T) and A. palladensis JCM 13509(T), A. troitsensis KCTC 12362(T) and A. echinorum KCTC 22013(T) were only 20.2±0.3 %, 22.6±0.6 % and 9.1±2.6 %, respectively. On the basis of phenotypic and molecular features, strain HP12(T) represents a novel species of the genus Arenibacter, for which the name Arenibacter hampyeongensis sp. nov. is proposed. The type strain is HP12(T) ( = KACC 16193(T) = JCM 17788(T)).

Microbulbifer gwangyangensis sp. nov. and Microbulbifer pacificus sp. nov., isolated from marine environments.

Two novel Gram-stain-negative, chemoheterotrophic and strictly aerobic bacteria, strains GY2(T) and SPO729(T), were isolated from a tidal flat at Gwangyang Bay in Korea and a marine sponge sample from the Pacific Ocean, respectively. The two strains were halotolerant, catalase- and oxidase-positive, and non-motile rods. Optimum temperature and pH for growth of both strains were observed to be 35 °C and pH 7.0-7.5, but optimum salinity for strain SPO729(T) [2-3 % (w/v)] was slightly higher than that for strain GY2(T) (1-2 %). The major cellular fatty acids of both strains were C16 : 0, iso-C15 : 0, iso-C17 : 0, iso-C17 : 1ω9c, C18 : 1ω7c, iso-C11 : 0 and iso-C11 : 0 3-OH. The genomic DNA G+C contents of strains GY2(T) and SPO729(T) were 55.1 and 57.9 mol%, respectively, and ubiquinone 8 (Q-8) was detected as the sole respiratory quinone from the two strains. Phylogenetic analysis based on 16S rRNA gene sequences showed that strains GY2(T) and SPO729(T) formed tight phyletic lineages with members of the genus Microbulbifer. Strain GY2(T) was closely related to Microbulbifer okinawensis ABABA23(T) (98.2 %), strain SPO729(T) (98.0 %) and Microbulbifer donghaiensis CN85(T) (97.0 %); strain SPO729(T) was closely related to M. okinawensis ABABA23(T) (98.3 %) and M. donghaiensis CN85(T) (98.2 %). The DNA-DNA relatedness values of strain GY2(T) with M. okinawensis ABABA23(T), strain SPO729(T) and M. donghaiensis CN85(T) were 40.0±2.1 %, 13.1±3.9 % and 16.2±5.8 %, respectively, whereas those of strain SPO729(T) with M. okinawensis ABABA23(T) and M. donghaiensis CN85(T) were 48.0±4.0 % and 34.6±9.3 %, respectively. On the basis of phenotypic and molecular features, it is concluded that the two strains GY2(T) and SPO729(T) represent two novel species of the genus Microbulbifer, for which the names Microbulbifer gwangyangensis sp. nov. and Microbulbifer pacificus are proposed; the type strains are GY2(T) ( = KACC 16189(T) = JCM 17800(T)) and SPO729(T) ( = KCCM 42667(T) = JCM 14507(T)), respectively.

Halomonas cibimaris sp. nov., isolated from jeotgal, a traditional Korean fermented seafood.

Two moderately halophilic, facultatively aerobic, motile bacteria with flagella, designated strains 10-C-3(T) and 30-C-3, were isolated from jeotgal, a traditional Korean fermented seafood. Cells of the strains were observed to be ovoid-rods showing catalase- and oxidase-positive reactions and production of creamy-pink pigments. Growth of strain 10-C-3(T) was observed at 15-35 °C (optimum, 25-30 °C), at pH 5.5-9.0 (optimum, pH 7.0-7.5), and in the presence of 3-15 % (w/v) salts (optimum: 5-10 %). The two strains were found to contain C(18:1) ω7c, C(16:0), summed feature 3 (as defined by the MIDI system, comprising C(16:1) ω7c and/or C(16:1) ω6c), and C(12:0) 3-OH as the major cellular fatty acids. The G+C contents of the genomic DNA of strains 10-C-3(T) and 30-C-3 were determined to be 63.2 and 63.1 mol%, respectively and the respiratory quinone detected was ubiquinone 9 (Q-9) only. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strains 10-C-3(T)and 30-C-3 formed a distinct phyletic lineage within the genus Halomonas and are most closely related to Halomonas fontilapidosi 5CR(T) with 95.2 % of 16S rRNA sequence similarity. Strains 10-C-3(T)and 30-C-3 shared 99.2 % of 16S rRNA gene sequence similarity and their DNA-DNA relatedness value was 96.6 ± 0.9 %. On the basis of phenotypic, chemotaxonomic and molecular features, strains 10-C-3(T)and 30-C-3 represent a novel species of the genus Halomonas, for which the name Halomonas cibimaris sp. nov. is proposed. The type strain is 10-C-3(T) (= KACC 14932(T) = JCM 16914(T)).

Aestuariibaculum suncheonense gen. nov., sp. nov., a marine bacterium of the family Flavobacteriaceae isolated from a tidal flat and emended descriptions of the genera Gaetbulibacter and Tamlana.

A Gram-staining-negative, yellow-pigmented, strictly aerobic bacterium, designated strain SC17(T), was isolated from sediment of a tidal flat of Suncheon bay in South Korea. Cells were halotolerant, catalase- and oxidase-positive and non-motile rods. Growth of strain SC17(T) was observed at 5-40 °C (optimum, 25-30 °C), at pH 6.0-8.5 (optimum, pH 7.0) and in the presence of 1-8 % (w/v) NaCl (optimum, 1-2 %). The major cellular fatty acids were iso-C(15 : 0), summed feature 3 (comprising C(16 : 1)ω7c and/or C(16 : 1)ω6c and/or iso-C(15 : 0) 2-OH), iso-C(17 : 0) 3-OH, iso-C(15 : 1) G and anteiso-C(15 : 0.) The polar lipid content consisted of phosphatidylethanolamine and unidentified amino lipids and lipids. The G+C content of the genomic DNA was 46.4 mol% and the only respiratory quinone detected was menaquinone-6 (MK-6). Phylogenetic inference based on 16S rRNA gene sequences showed that strain SC17(T) formed a distinct phyletic lineage within the family Flavobacteriaceae and was most closely related to members of the genera Gaetbulibacter and Tamlana with 95.0-95.8 % sequence similarity. On the basis of phenotypic and molecular features, strain SC17(T) represents a novel genus of the family Flavobacteriaceae, for which the name Aestuariibaculum suncheonense gen. nov., sp. nov. is proposed. The type strain is SC17(T) (= KACC 16186(T) = JCM 17789(T)). Emended descriptions of the genera Gaetbulibacter and Tamlana are also proposed.

Kordiimonas aestuarii sp. nov., a marine bacterium isolated from a tidal flat.

A Gram-staining negative, strictly aerobic bacterium, designated 101-1(T), was isolated from a sea tidal flat, Taean, Korea. The strain formed small light-yellow, smooth, and circular colonies on marine agar. Cells were weakly halophilic, motile rods showing catalase- and oxidase-positive reactions. Growth of strain 101-1(T) was observed at 15-40 °C (optimum, 30 °C), pH 5.0-8.0 (optimum, pH 6.5-7.0) and 1.0-9.0% (w/v) NaCl (optimum, 2.0-3.5%). The G+C content of the genomic DNA was 53.3 mol%. Strain 101-1(T) contained ubiquinone-10 (Q-10) as the respiratory quinone and iso-C(17:1)ω9c, iso-C(15:0) and iso-C(17:0) as major fatty acids. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 101-1(T) formed a tight phylogenetic lineage with members of the genus Kordiimonas and was most closely related to Kordiimonas gwangyangensis GW14-5(T) and Kordiimonas lacus S3-22(T) with 97.3% and 96.3% 16S rRNA gene sequence similarities, respectively. The DNA-DNA relatedness values between strain 101-1(T) and K. gwangyangensis GW14-5(T) and K. lacus S3-22(T) were 24.8 ± 4.4% and 32.2 ± 3.6%, respectively. Based on the data from the phenotypic and genotypic studies, strain 101-1(T) represents a novel species of the genus Kordiimonas, for which the name Kordiimonas aestuarii sp. nov. is proposed. The type strain is 101-1(T) ( = KACC 16184(T) = JCM 17742(T)).