Sub-MICs of Azithromycin Decrease Biofilm Formation ofStreptococcus suisand Increase Capsular Polysaccharide Content ofS. suis.
Streptococcus suis(S. suis) caused serious disease symptoms in humans and pigs.S. suisis able to form thick biofilms and this increases the difficulty of treatment. After growth with 1/2 minimal inhibitory concentration (MIC) of azithromycin, 1/4 MIC of azithromycin, or 1/8 MIC of azithromycin, biofilm formation ofS. suisdose-dependently decreased in the present study. Furthermore, scanning electron microscopy analysis revealed the obvious effect of azithromycin against biofilm formation ofS. suis. Especially, at two different conditions (1/2 MIC of azithromycin non-treated cells and treated cells), we carried out comparative proteomic analyses of cells by using iTRAQ technology. Finally, the results revealed the existence of 19 proteins of varying amounts. Interestingly, several cell surface proteins (such as ATP-binding cassette superfamily ATP-binding cassette transporter (G7SD52), CpsR (K0FG35), Cps1/2H (G8DTL7), CPS16F (E9NQ13), putative uncharacterized protein (G7SER0), NADP-dependent glyceraldehyde-3-phosphate dehydrogenase (G5L259), putative uncharacterized protein (G7S2D6), amino acid permease (B0M0G6), and NsuB (G5L351)) were found to be implicated in biofilm formation. More importantly, we also found that azithromycin affected expression of the genescps1/2H, cpsRandcps16F. Especially, after growth with 1/2 MIC of azithromycin and 1/4 MIC of azithromycin, the capsular polysaccharide content ofS. suiswas significantly higher.
College of Veterinary Medicine, Northeast Agricultural University Harbin, China.
Yan-Bei
YB
Yang
College of Veterinary Medicine, Northeast Agricultural University Harbin, China.
Jian-Qing
JQ
Chen
College of Veterinary Medicine, Northeast Agricultural University Harbin, China.
Yu-Lin
YL
Zhao
College of Veterinary Medicine, Northeast Agricultural University Harbin, China.
Jing-Wen
JW
Bai
College of Veterinary Medicine, Northeast Agricultural University Harbin, China.
Wen-Ya
WY
Ding
College of Veterinary Medicine, Northeast Agricultural University Harbin, China.
Yong-Hui
YH
Zhou
College of Veterinary Medicine, Northeast Agricultural University Harbin, China.
Xue-Ying
XY
Chen
Heilongjiang Academy of Agricultural Sciences Harbin, China.
Di
D
Liu
College of Veterinary Medicine, Northeast Agricultural University Harbin, China.
Yan-Hua
YH
Li
Streptococcus suis; azithromycin; biofilm formation; capsular polysaccharide; proteomics