Concentration of bacterial species indicative of fecal contamination in the gut of mangrove oysters (Crassostrea gasar) is a major concern for public health and food surveillance. Our work aimed to determine the occurrence, antibiotic-resistance, phylogenetic profile and virulence of Escherichia coli strains isolated from C. gasar farmed in four estuaries of Amazonia. Santo Antônio de Urindeua was the sampling point with the highest number of E. coli cells in oyster samples (10⁴ per 100 g of sample). Twenty-four isolates (52.2%) showed resistance to cephalotin and 18 to amoxicillin (39.1%). Eighteen clonal populations were determined by rep-PCR and were mainly affiliated to the pathogenic and commensal phylo-groups B1 and D. The presence of elt genes suggests that 10 of these clones belong to the Enterotoxigenic Escherichia coli pathotype. Plasmids, mostly of the F incompatibility group, were detected in the majority of the strains. All isolates were susceptible to last-resort antibiotics.

指示红树林牡蛎（Crassostrea gasar）肠道中粪便污染的细菌物种的浓度是公共卫生和食品监测的主要关注点。我们的工作旨在确定从亚马逊河四个河口养殖的加斯加斯虫中分离得到的大肠杆菌菌株的发生，耐药性，系统发育谱和毒力。SantoAntôniode Urindeua是牡蛎样品中大肠杆菌细胞数量最多的采样点（10 ⁴每100克样品）。24株分离株（52.2％）显示出对头孢菌素的耐药性，18株对阿莫西林耐药（39.1％）。十八克隆群体通过REP-PCR确定并且主要是附属于致病共生和phylo基团B1和D的存在ELT基因表明，这些克隆的10属于肠毒素大肠杆菌致病型。在大多数菌株中检测到质粒，大多数是F不相容性组。所有分离株均对最后的抗生素敏感。