AUTHOR=Hao Haihong , Fang Xia , Han Jing , Foley Steven L. , Wang Yulian , Cheng Guyue , Wang Xu , Huang Lingli , Dai Menghong , Liu Zhenli , Yuan Zonghui 

TITLE=Cj0440c Affects Flagella Formation and In Vivo Colonization of Erythromycin-Susceptible and -Resistant Campylobacter jejuni

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00729

DOI=10.3389/fmicb.2017.00729

ISSN=1664-302X

ABSTRACT=<p><italic>Campylobacter jejuni</italic> is one of the most common foodborne pathogen worldwide. A putative transcriptional regulator, <italic>Cj0440c</italic>, was up-regulated in the erythromycin-resistant <italic>C. jejuni</italic>, however, the precise role of <italic>Cj0440c</italic> is yet to be determined. The aim of this study was to determine the biological functions of <italic>Cj0440c</italic>. The <italic>Cj0440c</italic> isogenic mutants were constructed from erythromycin-susceptible <italic>C. jejuni</italic> NCTC 11168 (S) and -resistant <italic>C. jejuni</italic> 68-ER (R), designating as SM and RM, respectively. The isogenic Cj0440c mutants (SM and RM) and parental strains (S and R) were subjected to microarray and qRT-PCR analysis to examine the transcriptional profile changes contributed by <italic>Cj0440c</italic>. The antimicrobial susceptibility, flagellar morphology, <italic>in vitro</italic> growth and <italic>in vivo</italic> colonization in chickens were carried out to analyze the biological function of <italic>Cj0440c</italic>. The results showed that 17 genes were down-regulated in SM compared to S, while 9 genes were down-regulated in RM compared to R. The genes with transcriptional change were mainly involved in flagella biosynthesis and assembly. Using transmission electron microscopy, we found that the filaments were impaired in SM and lost in RM. The chicken colonization experiments showed that <italic>Cj0440c</italic> mutants (SM and RM) had reduced colonization ability in chickens when compared with corresponding parental strains (S and R). In conclusion, <italic>Cj0440c</italic> regulates flagella biosynthesis and assembly, and consequently affect the <italic>in vivo</italic> colonization of erythromycin-susceptible and -resistant <italic>C. jejuni</italic>.</p>