Baicalein Ameliorates Streptococcus suis-Induced Infection In Vitro and In Vivo.

Hao Lu,Chenchen Wang,Wenjia Lu,Jiajia Feng,Xiaodan Li,Manli Liu,Gaoyan Wang,Chen Tan,Xiangru Wang,Huanchun Chen

doi:10.3390/ijms22115829

Abstract

As an important zoonotic pathogen, Streptococcus suis (S. suis) infection has been reported to be a causative agent for variety of diseases in humans and animals, especially Streptococcal toxic shock-like syndrome (STSLS), which is commonly seen in cases of severe S. suis infection. STSLS is often accompanied by excessive production of inflammatory cytokines, which is the main cause of death. This calls for development of new strategies to avert the damage caused by STSLS. In this study, we found for the first time that Baicalein, combined with ampicillin, effectively improved severe S. suis infection. Further experiments demonstrated that baicalein significantly inhibited the hemolytic activity of SLY by directly binding to SLY and destroying its secondary structure. Cell-based assays revealed that Baicalein did not exert toxic effects and conferred protection in S. suis-infected cells. Interestingly, compared with ampicillin alone, Baicalein combined with ampicillin resulted in a higher survival rate in mice severely infected with S. suis. At the same time, we found that baicalein can be combined with meropenem against MRSA. In conclusion, these results indicate that baicalein has a good application prospect.

Highlights

IntroductionStreptococcus suis (S. suis) infection is associated with high mortality in humans and pigs
Introduction published maps and institutional affilStreptococcus suis (S. suis) infection is associated with high mortality in humans and pigs
Baicalein at 16 μg/mL in combination with ampicillin/meropenem significantly increased the activity of medicine against all MRSA and S. suis

Summary

Introduction

Streptococcus suis (S. suis) infection is associated with high mortality in humans and pigs. It induces symptoms, including septicaemia, meningitis, arthritis, and endocarditis. Since the first case in 1968, there have been reports of more than 1600 human S. suis infections [1]. The survivors of S. suis-induced meningitis, in most cases, present with severe sequelae such as deafness [6]. SS2 is an emerging zoonotic pathogen that infects humans and pigs It causes meningitis, endocarditis, and streptococcal toxic shock-like syndrome (STSLS) in humans [7]. In 2005, 215 cases of humans S. suis infection were reported in Sichuan province. Existing reports show that S. suis-derived STSLS causes iations

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