无乳链球菌的致病因子及其防治策略

Pathogenic factors of Streptococcus agalactiae and its prevention and treatment strategies

[背景]无乳链球菌(Streptococcus agalactiae)作为条件致病菌,能引起新生儿、老年人等免疫力较低人群感染致病甚至死亡,对其致病因子的研究可提供新的防治思路.[进展]无乳链球菌能产生毒素、胞外多糖、黏附蛋白等来帮助自身在宿主中定植,逃避免疫杀伤,进而导致疾病的发生发展.目前针对无乳链球菌的防治主要是抗生素干预,但滥用抗生素带来的细菌耐药性问题不容忽视,对该菌的检测方法也受到检测速度、灵敏度、成本等限制,因此目前针对无乳链球菌感染的防治方法依然有限.现阶段针对无乳链球菌致病因子及其耐药性的研究已被大量报道,本文对这些研究进行归纳总结,并阐述无乳链球菌防治方法的新探索及其进展.[展望]上述进展为科研人员后续深入研究无乳链球菌并开发相应防治措施提供了理论基础.但目前对无乳链球菌的了解只是冰山一角,而且在检测手段上还缺乏高效、灵敏的方法.未来对无乳链球菌与宿主的作用靶点、检测方法开展深入研究,有望找到特异性防治无乳链球菌感染的药物,降低无乳链球菌带来的危害.

[Background]Streptococcus agalactiae,also known as group B Streptococcus(GBS),is an opportunistic pathogen belonging to Gram-positive bacteria.It exhibits a high incidence among newborns,the elderly,and individuals with compromised immune systems,presenting a significant threat to public health.Furthermore,its impact on livestock and fisheries is considerable,as it is a major pathogen responsible for mastitis in cows and the mortality of tilapia.When colonized,GBS inhabits the gastrointestinal and urogenital tracts within the human body,with gastrointestinal GBS potentially acting as a source for urogenital GBS.In cases of weakened immunity,it can breach the bloodstream,resulting in conditions such as meningitis,sepsis,and fatality.The investigation of the pathogenic factors associated with GBS is paramount for the development of effective prevention and treatment strategies.[Progress]Research has revealed that GBS produces a series of virulence factors that enable it to successfully colonize and cause disease within the host.The process of GBS infection can be broadly divided into three steps.Firstly,through the action of adhesins,hemolysins,and other invasion-associated virulence factors,GBS attaches to and invades host cells.Subsequently,GBS evades host immune attacks by utilizing its own immune evasion factors,such as capsular polysaccharides or biofilm formation,allowing the bacteria to survive and proliferate within the host.Finally,through the secretion of toxins,GBS causes tissue damage leading to disease manifestation.The secretion system is an important mechanism for bacteria to release toxins and regulate protein function.Recently,the existence of a typeⅦsecretion system has been discovered in GBS research,although further investigation is required.In summary,understanding these pathogenic factors is crucial for unraveling the invasion mechanisms and infection processes of GBS,as well as for developing effective prevention and treatment strategies.The infection of GBS is a significant concern that cannot be ignored,and current strategies relying on antibiotics for prevention and control have notable shortcomings.Penicillin-binding protein,a component of bacterial cell walls,not only allows bacteria to evade the host s immune response but also binds to penicillin-type antibiotics,affecting the efficacy of antibiotics.The resistance of GBS strains to antibiotics limits treatment effectiveness,enabling bacteria to resist host defense mechanisms and antibiotic therapy,thereby enhancing their pathogenicity.Furthermore,the disruption of the intestinal flora by antibiotics may have long-term effects on host health.Moreover,existing methods for GBS detection have limitations in terms of speed,sensitivity,and cost,hindering effective disease management and prevention.Despite these challenges,the development of new prevention strategies and treatment approaches is still underway.Researchers are currently exploring alternative targets for anti-microbial therapy,such as non-antibiotic compounds and host-directed interventions.However,due to the need to balance safety and efficacy concerns,the path of research is fraught with difficulties,resulting in slow progress.Nevertheless,the prospects are promising.Additionally,there is a growing emphasis on the development of rapid,sensitive,and cost-effective detection methods,such as molecular diagnostics and immunological analyses.These methods are enhancing our ability to identify and manage GBS infections.[Perspective]The current understanding of the pathogenic factors and resistance mechanisms of GBS serves as a cornerstone for further research.Nevertheless,the exploration of the intricate interactions between this bacterium and its host is still in its nascent stages.The investigation of GBS and its pathogenic factors stands as a pivotal research domain in public health and livestock management,harboring numerous enigmas and challenges yet to be unraveled.Sustained research efforts and the advancement of novel technologies are imperative for enhancing our capacity to prevent,detect,and treat infections caused by this significant pathogen.Future research endeavors will necessitate interdisciplinary collaboration,integrating insights from disciplines such as molecular biology,microbiology,and immunology,to furnish more efficacious strategies for the prevention and management of GBS infections.