Jing Hu 1,2,3,†, Jiahe Zhou 4,†, Leping Wang 2,3, Zhongwei Chen 2,3, Yizhou Tan 1,2,3, Yangyan Yin 1,2,3, Zhe Pei 5, Changting Li 2,3, Huili Bai 1,2,3, Chunxia Ma 2,3, Ling Teng 1,2,3, Yongcui Feng 2,3, Xian Li 6,*, Yingyi Wei 1,* and Hao Peng 2,3,*
1 College of Animal Science and Technology, Guangxi University, Nanning 530004, China
2 Guangxi Key Laboratory of Veterinary Biotechnology, Guangxi Veterinary Research Institute,
Nanning 530001, China
3 Key Laboratory of China (Guangxi)-Association of Southeast Asian Nations (ASEAN) Cross-Border Animal
Disease Prevention and Control, Ministry of Agriculture and Rural Affairs of China, Nanning 530001, China
4 School of the Integrated Chinese and Western Medicine, Hunan University of Chinese Medicine,
Changsha 410208, China
5 School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
6 Guangxi Agricultural Engineering Vocational Technical College, Nanning 532100, China
†These authors contributed equally to this work.
*These authors contributed equally as corresponding authors.
Vet. Sci. 2025, 12, 793. doi: 10.3390/vetsci12090793.
Abstract
An outbreak characterized by clinical signs of diarrhea and paralysis, occasionally progressing to fatal outcomes, occurred at an ostrich breeding facility. Conventional antibiotic treatments proved ineffective. To investigate the etiology of the disease, brain and liver specimens were collected for diagnostic analysis. An Escherichia coli (E. coli) isolate, designated strain HZDC01, was obtained from cerebral tissues, and whole-genome sequencing was performed for genomic characterization. Genomic analysis revealed that the chromosomal DNA harbors numerous resistance genes, conferring multidrug resistance through complex mechanisms. Furthermore, a p0111 type plasmid carrying the blaCTX-M-55 gene and an IncX1 type plasmid harboring rmtB, sul1, APH(6)-Id, tet(A), AAC(3)-IIc, aadA2, blaTEM-1B, floR genes were identified. These plasmids carry numerous mobile genetic elements that can disseminate via horizontal gene transfer, thereby amplifying the risk of resistance-gene spread within bacterial populations. Additionally, ibeB and ibeC genes, which encode proteins involved in the invasion of brain microvascular endothelial cells, were identified. These genes may facilitate E. coli penetration of the blood–brain barrier, potentially leading to meningitis and posing a life-threatening risk to the host. This is the first report of the isolation and characterization of extended-spectrum beta-lactamase E. coli from the brain of an ostrich with paralysis. The findings provide valuable genomic insights into the antimicrobial resistance profiles and pathogenic mechanisms of ostrich-derived E. coli isolates.
Keywords Escherichia coli; ESBL; multidrug resistance; virulence factors; ostrich;whole-genome sequencing