Migratory birds are recently recognized as Vibrio disease vectors, but may be widespread transporters of Vibrio strains. We isolated Vibrio cholerae (V. cholerae) and Vibrio metschnikovii (V. metschnikovii) strains from migratory bird epidemic samples from 2017 to 2018 and isolated V. metschnikovii from migratory bird feces in 2019 from bird samples taken from the Inner Mongolia autonomous region of China. To investigate the evolution of these two Vibrio species, we sequenced the genomes of 40 V. cholerae strains and 34 V. metschnikovii strains isolated from the bird samples and compared these genomes with reference strain genomes. The pan-genome of all V. cholerae and V. metschnikovii genomes was large, with strains exhibiting considerable individual differences. A total of 2,130 and 1,352 core genes were identified in the V. cholerae and V. metschnikovii genomes, respectively, while dispensable genes accounted for 16,180 and 9,178 of all genes for the two strains, respectively. All V. cholerae strains isolated from the migratory birds that encoded T6SS and hlyA were non-O1/O139 serotypes without the ability to produce CTX. These strains also lacked the ability to produce the TCP fimbriae nor the extracellular matrix protein RbmA and could not metabolize trimetlylamine oxide (TMAO). Thus, these characteristics render them unlikely to be pandemic-inducing strains. However, a V. metschnikovii isolate encoding the complete T6SS system was isolated for the first time. These data provide new molecular insights into the diversity of V. cholerae and V. metschnikovii isolates recovered from migratory birds.

Colistin is used as one of the last available choices of antibiotics for patients infected by carbapenem-resistant bacterial strains, but the unrestricted use of colistin aggravated the acquisition and dissemination of mobile colistin resistance ( mcr ) genes. So far, 10 mcr genes have been reported in four continents around the world.

Background: In August 2018, a large number of migratory birds died in Chifeng, Neimeng. We were entrusted by local animal disease prevention and control center to collect the migratory bird epidemic materials and their living environmental water, and in 2019, we collect the local migratory bird stool and their living environmental water again. The bacterial communities in migratory bird epidemic materials, water and aquatic plants are profifiled by high-throughput sequencing of the V3–V4 hypervariable region of 16S rDNA gene.Results: We found that the dominant phylum between migratory bird epidemic materials, water and aquatic plant were Proteobacteia, Bacteroidetes, Firmicutes, Fusobacteria and Verrucomicrobia in 2018. One year later, we found that the dominant phylum between migratory bird stool, water and aquatic plant were Proteobacteia, Firmicutes, Cyanobacteria, Bacteroidetes. The relative abundance among bacterial phylum notably differed between two years. The relative abundance of Fusobacteria and Verrucomicrobia were higher in samples in 2018, while that of Cyanobacteria was higher in water, 2019. The relative abundance of Fusobacteria in migratory bird epidemic materials began to decline in the later period over time. At genus level, the relative abundance of Vibrio, Clostridium and other patnogenic bacteria decreased markedly and disappeared in 2019. The salt content and pH show a downward trend.Conclusions: Differences in diet and geographical location can lead to diversification in migratory bird intestinal flora. It is necessary to pay attention to diversification in intestinal flora of migratory birds, especially the abundance of vibrio in intestine. The overall structure of intestinal flora and relative abundance changes of various species are showed intuitively by 16S rDNA amplicon. But comparing to PCR which using specific primers, the accuracy and sensitivity are relatively poor. In the case of purposeful detection, it can be used in combination with both 16S rDNA amplicon and PCR which using specific primers. They are more accurately, because of supplement each other.

This study presents a comprehensive genomic epidemiology analysis on global sequenced Morganella isolates. First, a genome sequence-based species classification scheme for Morganella is established with a higher resolution and accuracy than those of the conventional scheme.