BACTERIAL COMMUNITIES OF THE OYSTERS Crassostrea corteziensis AND C. sikamea OF COSPITA BAY, SINALOA, MEXICO

Abstract

This work aimed to quantify the bacterial loads and determine the taxonomic composition of the microbial communities of oysters Crassostrea corteziensis and C. sikamea, as well as the surrounding waters of Cospita Bay, using two sets of samples (M1 and M4) obtained in the dry season and two (M2 and M3) in the rainy season. Bacterial loads were quantified with the viable count technique and out of the 320 strains isolated for their different morphologies, 84 were identified with molecular techniques to the species level. These species pertained to the families Vibrionaceae, Bacillaceae, Brucellaceae, Micrococcaceae, Pseudoalteromonaceae, Rhodobactereceae, Shewanellaceae and Staphylococcaceae. The higher concentrations of total bacteria were in the rainy season (samples M2 and M3), when families Vibrionaceae and Brucellaceae dominated. The highest Vibrio spp. and Pseudomonas spp. concentrations were in winter (samples M4). Probably because of its poor health conditions, the Kumamoto oyster C. sikamea had the highest diversity of bacterial species and the highest number of known pathogens for aquatic organisms. Palabras clave: bacterias, ostiones cultivados, ostiones silvestres RESUMEN En la presente investigación se cuantificó la carga bacteriana y se determinó la composición de la microbiota de los ostiones Crassostrea corteziensis y C. sikamea, así como del agua circundante de Bahía Cospita, usando dos muestras obtenidas durante el periodo de estiaje (muestreos M1 y M4) y dos obtenidas en el periodo de lluvias (muestreos M2 y M3). La carga bacteriana se cuantificó con la técnica de cuenta viable y se aislaron con criterios morfológicos 320 cepas, de las cuales de 84 se identificaron con técnicas moleculares hasta el nivel de especie y fueron agrupadas en las familias Vibrionaceae, Bacillaceae, Brucellaceae, Micrococcaceae,

Tropical and Subtropical Ostreidae of the American Pacific: Taxonomy, Biology, Ecology, and Genetics

“…Bacterial infections have been little studied in the subtropical and tropical oysters of the American Pacific, and, although there is a relationship of bacterial infection when oysters are infected with the OsHV-1 virus (C´aceres-Mart´ınez & V´azquez-Yeomans 2013), there are no specific studies that can determine the type of these infections. Luis-Villasen˜or et al (2018) conducted a study on the communities of the oysters Crassostrea corteziensis and Crassostrea sikamea from commercial oyster farms in Mexico. They found that the Kumamoto oyster C. sikamea presented a greater diversity of species and the highest number of pathogenic bacteria for aquatic organisms, which is a probable reflection of their poor health status in tropical culture.…”