title: Typing Discrepancy Between Phenotypic and Molecular Characterization Revealing an Emerging Biovar 9 Variant of Smooth Phage-Resistant B. abortus Strain 8416 in China.
abstract: A newly isolated smooth colony morphology phage-resistant strain 8416 isolated from a 45-year-old cattle farm cleaner with clinical features of brucellosis in China was reported. The most unusual phenotype was its resistance to two Brucella phages Tbilisi and Weybridge, but sensitive to Berkeley 2, a pattern similar to that of Brucella melitensis biovar 1. VITEK 2 biochemical identification system found that both strain 8416 and B. melitensis strains shared positive ILATk, but negative in other B. abortus strains. However, routine biochemical and phenotypic characteristics of strain 8416 were most similar to that of B. abortus biovar 9 except CO2 requirement. In addition, multiple PCR molecular typing assays including AMOS-PCR, B. abortus special PCR (B-ab PCR) and a novel sub-biovar typing PCR, indicated that strain 8416 may belong to either biovar 3b or 9 of B. abortus. Surprisingly, further MLVA typing results showed that strain 8416 was most closely related to B. abortus biovar 3 in the Brucella MLVA database, primarily differing in 4 out of 16 screened loci. Therefore, due to the unusual discrepancy between phenotypic (biochemical reactions and particular phage lysis profile) and molecular typing characteristics, strain 8416 could not be exactly classified to any of the existing B. abortus biovars and might be a new variant of B. abortus biovar 9. The present study also indicates that the present phage typing scheme for Brucella sp. is subject to variation and the routine Brucella biovar typing needs further studies.
authors.affiliation: Department of Immunology and Microbiology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China ; Baotou Municipal Center for Disease Control and Prevention Baotou, China.
authors.forename: Yao-Xia
authors.initials: YX
authors.lastname: Kang
authors.affiliation: Department of Immunology and Microbiology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China.
authors.forename: Xu-Ming
authors.initials: XM
authors.lastname: Li
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention Beijing, China.
authors.forename: Dong-Ri
authors.initials: DR
authors.lastname: Piao
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention Beijing, China.
authors.forename: Guo-Zhong
authors.initials: GZ
authors.lastname: Tian
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention Beijing, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Jiang
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention Beijing, China.
authors.forename: En-Hou
authors.initials: EH
authors.lastname: Jia
authors.affiliation: Baotou Municipal Center for Disease Control and Prevention Baotou, China.
authors.forename: Liang
authors.initials: L
authors.lastname: Lin
authors.affiliation: State Key Laboratory for Infectious Disease Prevention and Control, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Institute for Communicable Disease Control and Prevention Beijing, China.
authors.forename: Bu-Yun
authors.initials: BY
authors.lastname: Cui
authors.affiliation: Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca NY, USA.
authors.forename: Yung-Fu
authors.initials: YF
authors.lastname: Chang
authors.affiliation: Department of Immunology and Microbiology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China.
authors.forename: Xiao-Kui
authors.initials: XK
authors.lastname: Guo
authors.affiliation: Department of Immunology and Microbiology, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine Shanghai, China ; Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, Ithaca NY, USA.
authors.forename: Yong-Zhang
authors.initials: YZ
authors.lastname: Zhu
keywords: B. abortus; MLVA typing; smooth phage-resistant (SPR); unusual biochemical reactions