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Ciprofloxacin induces mutagenesis to antibiotic resistance independent of UmuC in Streptococcus uberis
Author(s) -
Varhimo Emilia,
Savijoki Kirsi,
Jefremoff Hanna,
Jalava Jari,
Sukura Antti,
Varmanen Pekka
Publication year - 2008
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2008.01634.x
Subject(s) - streptococcus uberis , biology , mutagenesis , ciprofloxacin , microbiology and biotechnology , point mutation , insertional mutagenesis , mutant , antibiotics , rpob , streptococcus , genetics , bacteria , gene , 16s ribosomal rna
Summary Streptococcus uberis is an environmental bovine mastitis pathogen capable of UV‐inducible SOS mutagenesis. Bacterial SOS systems can be induced by several chemicals including also antibiotics used in clinical practice. Here, we have studied the effect of ciprofloxacin, a fluoroquinolone antibiotic and known inducer of SOS, on mutations leading to antibiotic resistance in S. uberis . Mutation frequencies and spectra were compared in a wild‐type S. uberis strain and its Δ umuC derivative. The results revealed that concentrations of ciprofloxacin corresponding to 0.3–0.5× minimum inhibitory concentration (MIC) induce mutagenesis independent of UmuC. Partial sequencing of the rpoB gene of individual rifampin‐resistant clones from wild‐type and Δ umuC strains revealed a similar but complex pattern of point mutations including transitions, transversions and deletions/insertions. It was previously shown that UV induces mainly transition‐type mutations and UmuC is essential for the process. Thus, the results presented here demonstrate that S. uberis employs distinct mechanisms for ciprofloxacin and UV‐induced mutagenesis, which is a striking difference to Escherichia coli SOS model.