Identification of Virulence-Associated Markers in Escherichia Coli Isolated from Captive Red-Browed Amazon Parrot (Amazona Rhodocorytha)

ABSTRACT Due to the genetic similarity of pathogenic Escherichia coli isolated from birds and pathotypes of human origin, it is suggested that they have a common ancestor and may exchange virulence-associated genes. This study aimed to detect virulence-associated genes in E. coli strains isolated from the Red-browed Amazon parrot (Amazona rhodocorytha) kept at a conservation institute in Brazil. High genetic variability in virulence was observed, since 12 virulence profiles were found among 14 strains. The number of virulence-associated genes of single strains ranged from 5 to 22 out of 33 genes tested, and only one strain did not present any virulence genes. Regarding adhesion genes, most strains presented from two to five genes, and crlA (85.7%) and fimC (85.7%) were the most frequent. Frequencies were similar for invasion and iron acquisition genes. Variations among genes were observed for serum resistance and toxin-related genes. Some of the E. coli strains isolated from parrots presented virulence genes that are commonly associated with pathotypes of human origin, including newborn meningitis E. coli, uropathogenic E. coli, and sepsis-associated E. coli. It is noteworthy that some of these genes were present in the majority of the analyzed strains. Our results indicate that these strains detected in clinically healthy parrots can be potential reservoirs of several virulence-associated genes. These genes can be transmitted to other E. coli strains, including those that affect humans. These E. coli strains present a high pathogenic potential of virulence-associated genes in extraintestinal pathogenic E. coli strains.摘要：由于从鸟类分离的致病性大肠杆菌（pathogenic Escherichia coli）与人类来源的致病型菌株存在遗传相似性，有研究表明二者拥有共同祖先，且可发生毒力相关基因的交换。本研究旨在对巴西某保护机构饲养的红眉亚马逊鹦鹉（Amazona rhodocorytha）分离得到的大肠杆菌菌株的毒力相关基因进行检测。研究发现菌株的毒力存在较高遗传变异性：14株受试菌株中共检出12种毒力谱型。单株菌株携带的毒力相关基因数量在本次检测的33个目标基因中分布为5至22个，仅1株菌株未携带任何毒力基因。针对黏附素基因，多数菌株携带2至5个该类基因，其中crlA（85.7%）与fimC（85.7%）的检出频率最高。侵袭相关基因与铁摄取相关基因的检出频率较为相似。血清抗性相关基因及毒素相关基因则存在较大变异。部分从鹦鹉体内分离的大肠杆菌菌株携带了通常与人类致病型相关的毒力基因，包括新生儿脑膜炎致病性大肠杆菌（newborn meningitis E. coli）、尿路致病性大肠杆菌（uropathogenic E. coli）及败血症相关性致病性大肠杆菌（sepsis-associated E. coli）。值得注意的是，此类部分基因在多数受试菌株中均有检出。本研究结果表明，这些从临床健康鹦鹉体内分离得到的菌株可作为多种毒力相关基因的潜在储存宿主。此类基因可传播至其他大肠杆菌菌株，包括对人类具有致病性的菌株。上述大肠杆菌菌株在肠外致病性大肠杆菌（extraintestinal pathogenic E. coli）菌株中展现出较高的毒力相关基因致病潜能。