肠外致病性大肠杆菌致病机制及公共卫生学意义

Pathogenic mechanism and public health significance of extraintestinal pathogenic Escherichia coli (ExPEC)

摘要:

致病性大肠杆菌包括肠致病性大肠杆菌(intestinal pathogenic Escherichia coli, IPEC)和肠外致病性大肠杆菌(extraintestinal pathogenic E. coli, ExPEC)，可引起人和动物多种感染性疾病。ExPEC主要在肠道外其他组织脏器定殖并导致感染，包括尿道致病性大肠杆菌(uropathogenic E. coli, UPEC)、新生儿脑膜炎大肠杆菌(newborn meningitis E. coli, NMEC)和禽致病性大肠杆菌(avian pathogenic E. coli, APEC)。人源ExPEC (UPEC和NMEC)主要引起人尿道感染、肾盂肾炎和新生儿脑膜炎，而APEC可导致禽类的大肠杆菌病，造成家禽业的巨大经济损失。另外，乳腺致病性大肠杆菌(mammary pathogenic E. coli, MPEC)和猪源ExPEC可导致奶牛乳房炎、猪的肺炎及急性败血症等病症。研究发现，ExPEC类菌株在基因组结构上很相似，与IPEC本质区别在于致病机制不同，ExPEC具有很多相同的毒力基因和耐药基因，而且动物源ExPEC的毒力基因和耐药基因可通过食用动物传播给人类，危害人类健康，提示动物源ExPEC是人源ExPEC (NMEC和UPEC)的毒力基因贮库，在公共卫生方面具有重要意义。本文对肠外致病性大肠杆菌的危害、毒力因子、致病机制及公共卫生学意义方面进行综述，有助于全面、深入地认识肠外致病性大肠杆菌。

Abstract:

Pathogenic Escherichia coli infecting humans and domesticated animals can be classified into intestinal and extraintestinal pathogenic E. coli. Extraintestinal pathogenic E. coli (ExPEC) mainly colonizes tissues and organs outside the intestine and causes a wide range of extraintestinal infections, including uropathogenic E. coli (UPEC), newborn meningitis E. coli (NMEC), and avian pathogenic E. coli (APEC). Human ExPEC (including UPEC and NMEC) is the etiologic agent of urinary tract infections, pyelonephritis, and neonatal meningitis. APEC can lead to avian colibacillosis, causing huge economic losses in the poultry industry. In addition, mammary pathogenic E. coli and porcine ExPEC can bring forth cow mastitis, pig pneumonia, and acute sepsis. Studies have demonstrated that human and animal ExPEC strains have similarities in genomic structure, and they are essentially different from IPEC in pathogenic mechanism. ExPEC strains have a variety of similar virulence genes and resistance genes. The virulence genes and resistance genes in animal ExPEC can be transmitted to humans through edible animals, jeopardizing human health, which indicates that ExPEC strains from animals potentially serve as a reservoir of virulence genes and resistance genes for human ExPEC. ExPEC brings a tremendous burden on public health. Here, we review the hazards, virulence factors, pathogenic mechanism, and public health significance of ExPEC, hoping to enrich the knowledge about them.