摘要
      在作为环境宿主的水生细菌中，耐药性和毒力的共同出现往往被忽视，而这些特征向具有临床意义的菌株的传播在未来会带来不可预见的问题。在这项调查中，同时从多种水生栖息地（即地下水、运河、河流和沿海水域）鉴定的环境细菌的抗生素耐药性、金属耐受性、毒力因子和编码这些决定因素的基因进行了分析。来自污染河流和运河的菌株表现出更高的耐药性和毒力，尤其是格氏假单胞菌和荧光假单胞菌对碱性蛋白酶和磷脂酶的产生表现出较高的抗生素耐药性指数（ARI>0.6–0.8）。机会性病原体，包括副溶血性弧菌、溶藻弧菌、创伤弧菌、棒状杆菌和testosteroni Comamonas，表达了所有三种毒力因子，但抗性相对较低。然而，创伤弧菌和溶藻弧菌表现出多类抗生素耐药性（5/6类）。宏基因组分析显示，淡水中与β-内酰胺耐药性相对应的基因显著高于海水（p<0.05），而海水中的多药耐药性基因更高（p<0.05）。在所有水体中，大量的毒力基因属于分泌系统蛋白，其次是运动相关基因。可培养细菌显示，31个靶向基因与表达的抗性和毒力之间存在正相关和负相关的差异分布。在不动杆菌中，磷脂酶的产生、其他毒力基因（OVG）和对DNA合成抑制剂（DSI）的抗性之间存在显著的正相关。在假单胞菌中，毒素基因（toxA、eta、hlyA和stx）与细胞壁合成抑制剂抗性（CSI）以及OVG和粘附基因（eae、afa、papC和papA）呈正相关。网络分析显示，非病原体主导的基因ncc、arsB、strA、merA和intI的独特聚类，以及弧菌主导的基因pho、erm、nfsA、trh、lasB、tdh和invA的独特聚类。这项研究扩展了对水生水库细菌共同发生的耐药性和毒力的认识，这些细菌可能在未来对公众健康构成严重威胁。
Abstract
Co-occurrence of resistance and virulence is often overlooked in aquatic bacteria as environmental reservoirs, while transmission of these characteristics to clinically significant strains present unforeseen problems in future. In this investigation, environmental bacteria identified concurrently from multiple aquatic habitats viz., groundwater, canal, river and coastal waters were profiled for antibiotic resistance, metal tolerance, virulence factors and genes coding for these determinants. Strains from polluted river and canal exhibited higher resistance and virulence, especially Pseudomonas gessardii and P. fluorescens displayed high antibiotic resistance index (ARI > 0.6–0.8) with Alkaline Protease and Phospholipase production. Opportunistic pathogens including Vibrio parahaemolyticus, V. alginolyticus, V. vulnificus, Corynebacterium and Comamonas testosteroni expressed all three virulence factors with relatively low resistance. However, V. vulnificus and V. alginolyticus exhibited multiclass antibiotic resistance (5/6 classes). Metagenomic analysis revealed that genes corresponding to beta-lactam resistance were significantly higher (p < 0.05) in freshwater than seawater, while multidrug resistance gene were higher (p < 0.05) in seawater. In all aquatic bodies, abundant virulence genes belonged to secretion system proteins followed by motility related genes. Culturable bacteria revealed differential distribution of positive and negative correlation between 31 targeted genes with expressed resistance and virulence. Among Acinetobacter, significant positive correlation was found between Phospholipase production, other virulence genes (OVGs) and resistance to DNA Synthesis Inhibitors (DSI). In Pseudomonas, positive correlation was detected between toxin genes (toxA, eta, hlyA and stx) and resistance to cell wall synthesis inhibitors (CSI) as well as with OVGs and adhesion genes (eae, afa, papC and papA). Network analysis displayed unique clustering of genes ncc, arsB, strA, merA and intI dominated by non-pathogens and distinct clustering of genes pho, erm, nfsA, trh, lasB, tdh and invA by Vibrio. This investigation extends insight on co-occurring resistance and virulence in aquatic reservoir bacteria that could pose serious threats to public health in future.

https://www.sciencedirect.com/science/article/abs/pii/S0048969722063203