The Study of Diversity of Culturable Bacteria Community in Manure From Large-scale Dairy Farms in Yinchuan

The present study aims to investigate the culturable bacteria community of isolates from 4 kinds of samples (fresh fecal samples, accumulated manure without treatment samples, soil samples and waste water samples) collected from 3 large-scale dairy farms in Yinchuan. The samples were first diluted and plated on 8 different kinds of separation media such as nutrient agar medium, blood agar medium and MacConkey agar medium. Each of the single colony was then purified at least 3 times with the corresponding media for further analysis. After Gram staining, each isolate was further identified by VITEK 2 Compact automatic microbial biochemical identification system or 16S rDNA gene sequencing analysis. A total of 429 isolates were obtained from the samples through isolation and purification. After further analysis with VITEK 2 Compact automatic microbial biochemical identification system and 16S rDNA gene sequencing, a total of 358 strains were identified, these strains were distributed in 4 phyla, 6 classes, 15 orders, 23 families, 39 genera and 102 species. The rates of pathogenic bacteria in the samples were also calculated. Results show that conditional pathogenic bacteria accounted for 88.55% (317/358) of the total. The main conditional pathogens in the strains were S. aureus (11/358), E. coli (33/358) and S. thoraltensis (8/358). Strains mainly concentrated in the Firmicutes, Actinobacteria and Proteobacteria, and the conditional pathogenic bacteria may seriously threaten the human and animal as well as environmental if these fecal samples are discarded or used as fertilizer without proper treatment.