Mengjiao Du,1,2,* Cheng Chi,1,* LuYing Xiong,2 Jincheng Rong,1 Maoli Yi,1 Qi Zhao,1 Xiaohui Chi1 

1Department of Medical Laboratory, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, Shandong, People’s Republic of China; 2State Key Laboratory for Diagnosis and Treatment of Infectious Disease, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Qi Zhao; Xiaohui Chi, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yudong Road 20, Zhifu District, Yantai City, Shandong Province, 264000, People’s Republic of China, Email zhaoqiyhd@126.com; 15684003984@163.com

Purpose: Burkholderia is a conditioned pathogen in the medical setting and mainly affects patients with cystic fibrosis. We found co-infection with Burkholderia cepacia complex (Bcc) in many patients with respiratory tract infections, including H7N9 and COVID-19. However, previous studies have not focused on co-infections with BCC and respiratory viruses. Therefore, this study attempted to clarify the evolution of COVID-19-Bcc and H7N9-Bcc in terms of genetic background, antibiotic resistance, and virulence phenotypes.
Methods: This study retrospectively collected 49 Bcc isolated from patients with H7N9 and COVID-19 in a tertiary hospital of Zhejiang Province, of which 42 isolates were isolated from patients with H7N9, seven isolates were isolated from patients with COVID-19. The collected isolates were tested for antibiotic susceptibility, Galleria mellonella infection model, and whole-genome COVID-19-Bcc Characterization.
Results: The test results of 49 strains of Bcc showed that the strains isolated from COVID-19 patients accounted for 57.1% of multidrug-resistance resistant strains. Statistical analysis of the median lethal time of G. mellonella showed that the median fatal time for COVID-19-Bcc was shorter and more virulent than that of H7N9-Bcc (P< 0.05). The results of phylogenetic analysis indicated that COVID-19-Bcc may have evolved from H7N9-Bcc.
Conclusion: In this study, co-infection with BCC in many patients with respiratory tract infections, including H7N9 and COVID-19, was first identified and clarified that COVID-19-Bcc may have evolved from H7N9-Bcc and has the characteristics of hypervirulence and multidrug resistance.

Keywords: Burkholderia cepacia complex, COVID-19, H7N9, hypervirulence, multidrug-resistance, comparative genomic analysis