AUTHOR=Li Peizhen , Zhu Tingyuan , Zhou Danying , Lu Wei , Liu Hongmao , Sun Zhewei , Ying Jun , Lu Junwan , Lin Xi , Li Kewei , Ying Jianchao , Bao Qiyu , Xu Teng 

TITLE=Analysis of Resistance to Florfenicol and the Related Mechanism of Dissemination in Different Animal-Derived Bacteria

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2020.00369

DOI=10.3389/fcimb.2020.00369

ISSN=2235-2988

ABSTRACT=<p>Bacterial resistance to antibiotics has become an important concern for public health. This study was aimed to investigate the characteristics and the distribution of the florfenicol-related resistance genes in bacteria isolated from four farms. A total of 106 florfenicol-resistant Gram-negative bacilli were examined for florfenicol-related resistance genes, and the positive isolates were further characterized. The antimicrobial sensitivity results showed that most of them (100, 94.33%) belonged to multidrug resistance <italic>Enterobacteriaceae</italic>. About 91.51% of the strains carried <italic>floR</italic> gene, while 4.72% carried <italic>cfr</italic> gene. According to the pulsed-field gel electrophoresis results, 34 <italic>Escherichia coli</italic> were subdivided into 22 profiles, the genetic similarity coefficient of which ranged from 80.3 to 98.0%. The multilocus sequence typing (MLST) results revealed 17 sequence types (STs), with ST10 being the most prevalent. The genome sequencing result showed that the <italic>Proteus vulgaris</italic> G32 genome consists of a 4.06-Mb chromosome, a 177,911-bp plasmid (pG32-177), and a 51,686-bp plasmid (pG32-51). A <italic>floR</italic> located in a drug-resistant region on the chromosome of <italic>P. vulgaris</italic> G32 was with IS<italic>91</italic> family transposase, and the other <italic>floR</italic> gene on the plasmid pG32-177 was with an IS<italic>CR2</italic> insertion sequence. The <italic>cfr</italic> gene was located on the pG32-51 flanked by IS<italic>26</italic> element and TnpA26. This study suggested that the mobile genetic elements played an important role in the replication of resistance genes and the horizontal resistance gene transfer.</p>