New pathogen discovered

Until now unknown pathogen causes serious infections

24.02.2012

Swiss researchers have discovered a new pathogen of the genus Streptococcus. The pathogen known as Streptococcus tigurinus is mainly found in the oral cavity and can lead to serious infections.

The researchers led by Andrea Zbinden from the Institute of Medical Microbiology at the University of Zurich had isolated bacterial strains from several blood cultures of patients with endocarditis (inflammation of the heart's lining or heart valves), meningitis (meningitis) and spondylodiscitis (infectious disease of the intervertebral disc). They came across a new pathogen that Zbinden and colleagues consider to have a significant impact on the development of infectious diseases.

The newly discovered pathogen Streptococcus tigurinus, according to the Swiss scientists belongs to the genus of streptococci and is likely to be found in the oral cavity of most people. However, the actual distribution of the pathogens in the population has yet to be investigated, the researchers write in the current issue of the journal „International Journal of Systematic and Evolutionary Microbiology“. The identification of previously unknown pathogens was therefore only the first step. Now microbiologists and doctors can recognize this bacterium and make further investigations, Zbinden and colleagues emphasize the importance of their discovery. Streptococcus tigurinus shows, according to the scientists a similarity of maximum „97.6 percent among the phylogenetically closest related species“ on. There are clear molecular-biological and external differences compared to the related so-called greening streptococci, the Swiss scientists report. In finding the name for Streptococcus tigurinus, the researchers were guided by the Latin name of his locality - Zurich was in the 17th and 18th centuries „Tigurum“.

Like most greening streptococci, Streptococcus tigurinus is thought to be found in the oral cavity of many people, according to Swiss microbiologists. However, only a few of them become ill. Only when the pathogens enter the bloodstream through injuries or inflammations of the gums can serious infections be threatened, reports the research team led by Andrea Zbinden. Here, the bacteria attack the red blood cells and decompose the red blood pigment hemoglobin, resulting in the destruction of the blood cells. The breakdown product is a greenish substance, which gave the greening streptococci its name. The health consequences of spreading Streptococcus tigurinus in the organism are sometimes devastating, according to Swiss scientists. Thus, the pathogens apparently play an essential role in the development of meningitis, heart valve inflammation and inflammation of the vertebral bodies.

The first evidence of the new pathogen, the researchers succeeded in an endocarditis patient, where Streptococcus tigurinus was found in the heart valves and in the blood of the person affected. In her follow-up investigations, Andrea Zbinden and colleagues also discovered the pathogens in patients who suffered from infection of the meninges or intervertebral disc and vertebral body inflammation. All of these infectious diseases were apparently caused by the previously unknown streptococcal pathogen. The researchers hope that with the discovery of Streptococcus tigurinus in the future, a part of these infections can be prevented or at least improved therapy can be. (Fp)

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