Infection and Drug Resistance (Apr 2020)
Discovery of a Novel Hypervirulent Acinetobacter baumannii Strain in a Case of Community-Acquired Pneumonia
Abstract
Hua Zhou,1,* Paige MK Larkin,2,* Jinwei Huang,3,* Yake Yao,1 Bingquan Zhu,4 Qing Yang,5 Xiaoting Hua,6,7 Jianying Zhou,1 Shangxin Yang,2,8 Yunsong Yu6,7 1Department of Respiratory Diseases, First Affiliated Hospital of Zhejiang University, Hangzhou, Zhejiang, People’s Republic of China; 2Department of Pathology & Laboratory Medicine, University of California, Los Angeles, Los Angeles, CA, USA; 3Department of Respiratory Diseases, Sixth Affiliated Hospital of Wenzhou Medical University, Lishui, Zhejiang, People’s Republic of China; 4Department of Child Health Care, Zhejiang University Children’s Hospital, Hangzhou, Zhejiang, People’s Republic of China; 5State Key Laboratory for Diagnostic and Treatment of Infectious Diseases, First Affiliated Hospital of Zhejiang University, Hangzhou, People’s Republic of China; 6Department of Infectious Diseases, Sir Run Run Shaw Hospital of Zhejiang University, Hangzhou, People’s Republic of China; 7Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, People’s Republic of China; 8Zhejiang-California International Nanosystems Institute, Zhejiang University, Hangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Shangxin Yang; Yunsong YuDepartment of Infectious Diseases, Sir Run Run Shaw Hospital of Zhejiang University, Hangzhou 310016, People’s Republic of ChinaTel +86 571 87236873Email [email protected]; [email protected]: Acinetobacter baumannii is associated with both hospital-acquired infections and community-acquired pneumonia (CAP). Here, we describe a novel strain of A. baumannii in a case of CAP in a previously healthy rural villager from Central Eastern China.Materials and Methods: A. baumannii isolated from the patient (LS01) was compared to well-characterized pathogenic strain (AB5075), nosocomial circulating strain in China (ZJ06), and wild-type strain (ATCC17978). Growth rate studies were conducted under different environmental stressors, and virulence studies were performed using Galleria mellonella larvae. Whole genome sequencing (WGS) was performed using MinIon and MiSeq. Center for Genomic Epidemiology, CLCbio, Geneious, and Virulence Factors of Pathogenic Bacteria database were used for genomic analysis.Results: LS01 grew significantly faster at 37°C and 42°C and in the presence of zinc compared to other strains. LS01 was more virulent in G. mellonella, killing all larvae within 8 h. Although WGS revealed 44 virulence genes, these genes were also present in the other strains. While two chromosomally encoded β-lactamases were identified, there were no plasmids identified and LS01 was pan-susceptible to all antibiotics tested. Phylogenetic analysis revealed that the closest related strains were only 72.552% identical, supporting a novel strain.Conclusion: LS01 is a novel strain of hypervirulent yet pan-drug susceptible A. baumannii isolated from a patient with no prior hospitalizations, sick contacts, or any of the typical risk factors. This raises concerns for an emerging pathogen, and more epidemiological studies should be conducted to assess the prevalence of this A. baumannii strain.Keywords: Acinetobacter baumannii, hypervirulent, community-acquired pneumonia, novel strain, emerging pathogen
