Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Infect Genet Evol. 2018 Mar;58:27-33. doi: 10.1016/j.meegid.2017.12.012. Epub 2017 Dec 15.
In the present study, we screened a collection of 77 Proteus mirabilis clinical isolates for the presence of mutators, using the frequency of both rifampicin and fosfomycin resistance mutants as markers of spontaneous mutagenesis. We found that none of the strains in our collection are mutators for the rifampicin resistance (Rif) marker. Nevertheless, a significant fraction of the isolates (17%) show high frequencies of fosfomycin resistant mutants (Fos). We show that this increased mutability to Fos correlates with a low level of resistance to Fosfomycin (MICs 8-64μg/ml). These strains also show high frequencies of single step mutants with clinically relevant Fos resistance levels (MIC ≥256μg/ml). Our findings point out to the risk of fosfomycin resistance emergence in P. mirabilis.
在本研究中，我们使用利福平和磷霉素耐药突变体的频率作为自发突变的标记物，筛选了 77 株奇异变形杆菌临床分离株中突变体的存在情况。我们发现，我们收集的菌株中没有一种是利福平耐药（Rif）标记物的突变体。然而，相当一部分分离株（17%）显示出高频率的磷霉素耐药突变体（Fos）。我们表明，这种增加的对 Fos 的可变性与对磷霉素的低水平耐药性（MICs 8-64μg/ml）相关。这些菌株还显示出具有临床相关 Fos 耐药水平（MIC≥256μg/ml）的单步突变体的高频率。我们的研究结果表明，奇异变形杆菌中存在磷霉素耐药的风险。
