Einfluss von Cytarabin auf die Pathogenitätsfaktoren von Streptococcus mitis
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Streptococcus mitis belongs to the viridans streptococci and is a common cause of infections in neutropenic patients with hematologic alignancies. Therapy with high-dose cytarabine is a known risk factor for invasive infections. In this study, the impact of cytarabine on the virulence factors of S. mitis was investigated. 16 Streptococcus mitis and 2 Streptococcus oralis isolates originating from pediatric blood cultures were typed by pulsed-field gel electrophoresis. All the investigated strains were unrelated. If cytarabine influences the growth of S. mitis or other viridans streptococci was tested by monitoring the growth in serial dilutions of cytarabine. However, no significant influence of cytarabine could be detected. The impact of cytarabine on protein expression of S. mitis was investigated by 2-dimensional gel electrophoresis in the presence and absence of cytarabine. In cultures supplemented with cytarabine a lower expression of the hydrogen peroxide producing enzymes manganese superoxide dismutase and pyruvate oxidase was noted. Hydrogen-peroxide is a common cell and bacterial toxin. However determination of hydrogen peroxide production in S. mitis cells preloaded with cytarabine yielded inconclusive results, which may be due to technical reasons. Evaluation of the complex regulating networks controlling hydrogen peroxide production in S. mitis and the impact of cytarabine awaits further studies.
Subject HeadingsBakteriämie [GND]
Streptococcus mitis [MeSH]