Inflammation and Healing Cluster, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore DC, Queensland, 4558, Australia.
Eur J Clin Microbiol Infect Dis. 2021 Jan;40(1):181-192. doi: 10.1007/s10096-020-04066-5. Epub 2020 Oct 15.
Adherent-invasive Escherichia coli (AIEC) has been implicated as a microbiological factor in inflammatory bowel disease (IBD) pathogenesis. These strains are defined by their ability to adhere to and invade intestinal epithelial cells, and to survive and replicate in macrophages. We postulated that AIEC strains may commonly inhabit the gut of healthy individuals (HI), cause extraintestinal infections, and be found in sewage treatment plants (STP) and surface waters (SW). A total of 808 E. coli strains isolated from HI; patients with community-acquired urinary tract infection (CA-UTI), septicaemia and urosepsis; STP; and SW, showing a diffuse adhesion pattern to Caco-2 cells were included in this study. Typing of the strains using a combination of RAPD-PCR and PhPlate fingerprinting grouped them into 48 common clones (CCs). Representatives of each CC were tested for the ability to invade Caco-2 cells, survive and replicate in macrophages, and for the presence of six virulence genes commonly found among AIEC strains. Twenty CCs were deemed AIEC based on their ability to survive and replicate in macrophages, while encoding htrA, dsbA and clbA genes. These CCs primarily originated from HI and CA-UTI patients but were also detected in secondary locations including STP and SW. Strains lacking intramacrophagic survival and replication abilities were regarded as diffusely adhering E. coli (DAEC). Certain clones of AIEC are common in the gut of HI whilst promoting CA-UTI. The survival and persistence of AIEC in STP and SW may have serious public health ramifications for individuals predisposed to IBD.
黏附侵袭型大肠杆菌（AIEC）被认为是炎症性肠病（IBD）发病机制中的微生物因素。这些菌株的特点是能够黏附和侵袭肠道上皮细胞，并在巨噬细胞中存活和复制。我们推测，AIEC 菌株可能通常存在于健康个体（HI）的肠道中，引起肠道外感染，并存在于污水处理厂（STP）和地表水中（SW）。本研究共纳入了 808 株从 HI、社区获得性尿路感染（CA-UTI）、败血症和尿脓毒症患者、STP 和 SW 中分离出的、对 Caco-2 细胞呈弥散黏附模式的大肠杆菌菌株。使用 RAPD-PCR 和 PhPlate 指纹图谱组合对菌株进行分型，将它们分为 48 个常见克隆（CC）。对每个 CC 的代表菌株进行了侵袭 Caco-2 细胞、在巨噬细胞中存活和复制的能力以及 6 种常见于 AIEC 菌株的毒力基因的检测。根据在巨噬细胞中存活和复制的能力，以及编码 htrA、dsbA 和 clbA 基因的能力，将 20 个 CC 鉴定为 AIEC。这些 CC 主要来源于 HI 和 CA-UTI 患者，但也在 STP 和 SW 等二级地点检测到。缺乏细胞内存活和复制能力的菌株被认为是弥散黏附型大肠杆菌（DAEC）。某些 AIEC 克隆在 HI 肠道中很常见，同时也会引发 CA-UTI。AIEC 在 STP 和 SW 中的存活和持续存在可能对易患 IBD 的个体产生严重的公共卫生影响。
