Ichinohe N, Ohara-Nemoto Y, Nemoto TK, Kimura S, Ichinohe S
Effects of fosfomycin on Shiga toxin-producing Escherichia coli: quantification of copy numbers of Shiga toxin genes and their expression levels using real-time PCR. [JOURNAL ARTICLE]
J Med Microbiol 2009 Jun 4.
Antibiotic therapy for infection with Shiga toxin (Stx)-producing Escherichia coli (STEC) is considered as a risk factor for progression to a severe complication of hemolytic uremic syndrome (HUS), possibly because of Stxs release. However, the incidence of HUS in children with STEC infection was found to be not higher in Japan than in other countries, despite the use of antibiotics such as fosfomycin. Hence, it remains controversial whether the use of antibiotics for STEC infection is effective or harmful. Herein, we conducted the quantitative study of the effects of fosfomycin, norfloxacin, as well as 3 beta-lactams, panipenem, ceftazidime and aztreonam, on the copy numbers and mRNA levels of the stx1 and stx2 genes, by measuring those amounts in E. coli O157:H7 with real-time PCR. Both of the DNA copy numbers and mRNA levels, particularly stx2, were significantly increased with the norfloxacin treatment. In contrast, fosfomycin and panipenem markedly reduced the DNA copy numbers and stx mRNA levels, whereas ceftazidime and aztreonam did not change those levels. The reduced effects seemed to correlate with the antibacterial mechanism of by these antibiotics that cause rapid cell lysis of STEC cells. Taking into consideration the effects, the present results suggested that fosfomycin therapy is valid for STEC infection and not increase the risk of hemolytic uremic syndrome.
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