Occurrence of Helicobacter spp. and Fecal Bacterial Contamination in High-altitude Aquatic Environments from the Andes

Environmentally responsive changes in mucus indicators and microbiota of Chinese sturgeon Acipensersinensis

The impact of environmental factors on the health of the endangered Chinese sturgeon (Acipenser sinensis) and the potential hazards associated with sample collection for health monitoring pose urgent need to its conservation. In this study, Chinese sturgeons were selected from indoor and outdoor environments to evaluate metabolic and tissue damage indicators, along with a non-specific immune enzyme in fish mucus. Additionally, the microbiota of both water bodies and fish mucus were determined using 16S rRNA high-throughput sequencing. The correlation between the indicators and the microbiota was investigated, along with the measurement of multiple environmental factors. The results revealed significantly higher levels of two metabolic indicators, total protein (TP) and cortisol (COR) in indoor fish mucus compared to outdoor fish mucus (p < 0.05). The activities of acid phosphatase (ACP), alkaline phosphatase (ALP), creatine kinase (CK), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were significantly higher in indoor fish, serving as indicators of tissue damage (p < 0.05). The activity of lysozyme (LZM) was significantly lower in indoor fish (p < 0.01). Biomarker analysis at the phylum and genus levels in outdoor samples revealed that microorganisms were primarily related to the catabolism of organic nutrients. In indoor environments, microorganisms displayed a broader spectrum of functions, including ecological niche establishment, host colonization, potential pathogenicity, and antagonism of pathogens. KEGG functional enrichment corroborated these findings. Dissolved oxygen (DO), electrical conductivity (EC), ammonia nitrogen (NH3-N), turbidity (TU), and chemical oxygen demand (COD) exerted effects on outdoor microbiota. Temperature (TEMP), nitrate (NO3-), total phosphorus (TP), and total nitrogen (TN) influenced indoor microbiota. Changes in mucus indicators, microbial structure, and function in both environments were highly correlated with these factors. Our study provides novel insights into the health impacts of different environments on Chinese sturgeon using a non-invasive method.

Anthropogenic disturbance promotes the diversification of antibiotic resistance genes and virulence factors in the gut of plateau pikas (Ochotona curzoniae)

The prevalence and transmission of antibiotic resistance genes (ARGs) and virulence factors (VFs) pose a great threat to public health. The importance of pollution in determining the occurrence of ARGs and VFs in wildlife is poorly understood. Using a metagenomic approach, this study investigates the composition and functional pathways of bacteria, ARGs, and VFs in the gut microbiome of Plateau pikas in regions of medical pollution (MPR), heavy tourist traffic (HTR), and no contamination (NCR). We found that the abundance of probiotic genera (Clostridium, Eubacterium, Faecalibacterium, and Roseburia) were significantly lower in the HTR. The metabolic pathways of replication and repair in the endocrine and nervous systems were significantly enriched in the MPR, whereas endocrine and metabolic diseases were significantly enriched in the NCR. The Shannon and Gini–Simpson α-diversity indices of ARGs were highest in the HTR, and there were significant differences in β-diversity among the three regions. The resistance of ARGs to glycopeptide antibiotics increased significantly in the MPR, whereas the ARGs for aminocoumarins increased significantly in the HTR. The diversity of mobile genetic elements (MGEs) was significantly higher in the MPR than in other regions. We observed a strong positive correlation between ARGs and pathogenic bacteria, and the network structure was the most complex in the MPR. There were significant differences in the β-diversity of VFs among the three regions. Medical pollution led to significant enrichment of fibronectin-binding protein and PhoP, whereas tourism-related pollution (in the HTR) led to significant enrichment of LPS and LplA1. Our study indicates that environmental pollution can affect the structure and function of gut microbes and disseminate ARGs and VFs via horizontal transmission, thereby posing a threat to the health of wild animals.