Rezatofighi Seyede Elham, Najafifar Arash, Askari Badouei Mahdi, Peighambari Seyed Mostafa, Soltani Mohammad
Faculty of Science, Department of Biology, Shahid Chamran University of Ahvaz, Ahvaz, Iran.
Private Veterinary Practitioner, Independent Researcher, Tehran, Iran.
Front Vet Sci. 2021 Nov 24;8:758124. doi: 10.3389/fvets.2021.758124. eCollection 2021.
Avian pathogenic (APEC) is an important bacterial pathogen that causes avian colibacillosis and leads to huge economic losses in the poultry industry. Different virulence traits contribute to pathogenesis of APEC infections, and antimicrobial resistance (AMR) has also been an overwhelming issue in poultry worldwide. In the present study, we aimed to investigate and compare the presence of virulence-associated genes (VAGs), AMR, and phylogenetic group's distribution among APEC and avian fecal (AFEC) strains. from birds with colisepticemia and yolk sac infection (YSI) (APEC) plus strains from the feces of healthy birds (AFEC) were compared by the aforementioned traits. In addition, the clonal relatedness was compared using Enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). Although all strains were susceptible to fosfomycin, ceftriaxone, and cefixime, almost all strains (98%) were multi-drug resistant (MDR). All strains (except two) harbored at least three or more VAGs, and the virulence scores tended to be higher in pathogenic strains especially in the colisepticemic group. All phylogenetic groups were found in isolates from YSI, colisepticemia, and the feces of healthy birds; however, the frequency of phylogroups varied according to the source of the isolate. B1 and C phylogroups were statistically more likely to be found among APEC from YSI and colisepticemic groups, respectively, while phylogroup A was the most frequently occurring phylogroup among AFEC strains. Our findings also revealed that AMR and VAGs are not essentially co-evolved traits as in some instances AMR strains were more prevalent among AFEC. This reflects the divergent evolutionary pathways of resistance acquisition in pathogenic or non-pathogenic avian strains. Importantly, strains related to phylogenetic group C showed higher virulence score and AMR that requires further attention. To some extent, ERIC-PCR was able to group strains by isolation source, phylogroup, or virulence genes. Further integrated studies along with assessment of more detailed genotypic and phenotypic features could potentially lead to better understanding of virulence, resistance, and evolution of ExPEC.
禽致病性大肠杆菌（APEC）是一种重要的细菌病原体，可引起禽大肠杆菌病，并给家禽业造成巨大经济损失。不同的毒力特征有助于APEC感染的发病机制，而且抗菌药物耐药性（AMR）在全球家禽业中也是一个突出问题。在本研究中，我们旨在调查和比较毒力相关基因（VAGs）的存在情况、AMR以及APEC菌株和禽粪便（AFEC）菌株之间的系统发育群分布。将患有败血症和卵黄囊感染（YSI）的禽类的APEC菌株与健康禽类粪便中的菌株（AFEC）就上述特征进行比较。此外，使用肠杆菌重复基因间共识PCR（ERIC-PCR）比较克隆相关性。尽管所有菌株对磷霉素、头孢曲松和头孢克肟敏感，但几乎所有菌株（98%）都对多种药物耐药（MDR）。所有菌株（除两株外）都含有至少三种或更多的VAGs，并且致病菌株尤其是败血症组中的毒力得分往往更高。在YSI、败血症以及健康禽类粪便的分离株中均发现了所有的系统发育群；然而，系统发育群的频率因分离株来源而异。B1和C系统发育群在YSI和败血症组的APEC中分别更有可能在统计学上被发现，而A系统发育群是AFEC菌株中最常出现的系统发育群。我们的研究结果还表明，AMR和VAGs并非本质上共同进化的特征，因为在某些情况下，AMR菌株在AFEC中更为普遍。这反映了致病或非致病禽类菌株中耐药性获得的不同进化途径。重要的是，与C系统发育群相关的菌株显示出更高的毒力得分和AMR，需要进一步关注。在某种程度上，ERIC-PCR能够按分离来源、系统发育群或毒力基因对菌株进行分组。进一步的综合研究以及对更详细的基因型和表型特征的评估可能会更好地理解ExPEC的毒力、耐药性和进化。
