Identificación de bacterias patógenas en peces capturados en el Pacífico frente a Nicaragua

El objetivo de este estudio fue identificar bacterias patógenas en peces procedentes de 4 comunidades en la costa del Pacífico en el occidente de Nicaragua. Se recolectaron 62 peces para realizar el análisis microbiológico a partir de muestras de músculo, las cuales fueron inoculadas en agar tiosulfato citrato bilis sacarosa y agar tripticasa de soja. La identificación bacteriana se realizó mediante pruebas bioquímicas y de tolerancia a diferentes concentraciones de NaCl, y para determinar la resistencia bacteriana, se empleó el método Kirby-Bauer. Los resultados mostraron presencia de Vibrio metschnikovii en un 30.64% (IC 95%: 18.36–42.92) de las muestras de peces, mientras que Salinivibrio costicola fue detectada en un 22.58% (IC 95%: 11.37–33.79) de las muestras. Staphylococcus coagulasa negativa (SCN) fue detectada en un 82.30% (IC 95%: 71.94–92.57) de las muestras. Especies del género Vibrio fueron detectadas a una concentración de 3.9 × 103 UFC·g–1 en las muestras de peces de la comunidad Las Peñitas y de 2.52 × 103 UFC·g–1 en las de Poneloya, y estos valores fueron significativamente mayores (P = 0.003) que aquellos encontrados para las muestras de El Tránsito (5.25 × 102 UFC·g–1). Además, el 100% de las cepas de V. metschnikovii y S. costicola fueron resistentes a amoxicilina/ácido clavulánico y sensibles a ciprofloxacina. La carga bacteriana de S. costicola es propia de ambientes marinos y no representa riesgo sanitario. Sin embargo, V. metschnikovii puede estar presente en el pescado crudo y, por lo tanto, representa un peligro para la salud pública, así como también lo es SCN, que es un indicador de contaminación antropogénica.

Pan-Genome Analysis of Vibrio cholerae and Vibrio metschnikovii Strains Isolated From Migratory Birds at Dali Nouer Lake in Chifeng, China

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.

CHARACTERIZATION OF EXTRACELLULAR PROTEASE FROM VIBRIO METSCHNIKOVII STRAIN XMB 057

From various natural sources on skim milk agar plates 51protease producer bacteria wereisolated by primary screening. Secondary screening was done by zone of clearanceformed by cell free broth on gelatin agar plates. From diameter of zone of clearance potent protease best protease producers Vibrio metschnikovii strain Xmb 057 was isolated. It was biochemically characterized by performing some common biochemical tests. Effect of temperature and pH on protease by Vibrio metschnikovii strain Xmb 057 was studied. Optimum temperature and pH was 500C and 9 respectively make it suitable to be used in leather and detergent industry. Protease was tolerant to Ca++ and Mg++ which suggest its activity in detergents used even in hard water.

Vibrio salilacus sp. nov., a new member of the Anguillarum clade with six alleles of the 16S rRNA gene from a saline lake

A Gram-stain-negative, catalase- and oxidase-positive, facultatively aerobic bacterium, strain DSG-S6T, was isolated from Dasugan Lake (salinity 3.1 %, w/w), China. Its taxonomic position was determined by using a polyphasic approach. Cells of strain DSG-S6T were non-spore-forming, slightly bent rods, and motile by means of a single polar flagellum. Growth occurred in the presence of 0–7.0 % (w/v) NaCl (optimum, 2.0 %), at 4–35 °C (optimum, 30 °C) and at pH 6.0–10.5 (optimum, pH 8.0–8.5). C16 : 0, C18 : 1ω7c and C16 : 1ω7c and/or C16 : 1ω6c were the major fatty acids. Six alleles of the 16S rRNA gene sharing 98.9–99.9 % similarity were detected in strain DSG-S6T, which showed highest 16S rRNA gene sequence similarity to Vibrio aestuarianus ATCC 35048T (97.7 %), then to Vibrio pacinii LMG 19999T (97.6 %) and Vibrio metschnikovii CIP 69.14T (96.8 %). Multilocus sequence analysis of four housekeeping genes and 16S rRNA genes clearly clustered it as a member of the Anguillarum clade. Mean DNA–DNA relatedness between strain DSG-S6T and V. aestuarianus NBRC 15629T, V. pacinii CGMCC 1.12557T and V. metschnikovii JCM 21189T was 20.6 ± 2.3, 38.1 ± 3.5 and 24.2 ± 2.8 %, respectively. The DNA G+C content was 46.8 mol% (T m). Based on the data, it is concluded that strain DSG-S6T represents a novel species of the genus Vibrio, for which the name Vibrio salilacus sp. nov. is proposed. The type strain is DSG-S6T ( = CGMCC 1.12427T = JCM 19265T).