miR-203 drives breast cancer cell differentiation.

A hallmark of many malignant tumors is dedifferentiated (immature) cells bearing slight or no resemblance to the normal cells from which the cancer originated. Tumor dedifferentiated cells exhibit a higher capacity to survive to chemo and radiotherapies and have the ability to incite tumor relapse. Inducing cancer cell differentiation would abolish their self-renewal and invasive capacity and could be combined with the current standard of care, especially in poorly differentiated and aggressive tumors (with worst prognosis). However, differentiation therapy is still in its early stages and the intrinsic complexity of solid tumor heterogeneity demands innovative approaches in order to be efficiently translated into the clinic. We demonstrate here that microRNA 203, a potent driver of differentiation in pluripotent stem cells (ESCs and iPSCs), promotes the differentiation of mammary gland tumor cells. Combining mouse in vivo approaches and both mouse and human-derived tridimensional organoid cultures, we report that miR-203 influences the self-renewal capacity, plasticity and differentiation potential of breast cancer cells and prevents tumor cell growth in vivo. Our work sheds light on differentiation-based antitumor therapies and offers miR-203 as a promising tool for directly confronting the tumor-maintaining and regeneration capability of cancer cells.

Linezolid and vancomycin-resistant Enterococcus faecium peritonitis in a child after liver transplantation

No disponible

Bacteraemia due to meticillin-resistant Staphylococcus aureus carrying the mecC gene in a patient with urothelial carcinoma.

We present a case of bacteraemia due to meticillin-resistant Staphylococcus aureus (MRSA) carrying the mecC gene. The susceptibility to meticillin of Staphylococcus aureus was investigated directly from one blood culture bottle using GenomEra MRSA/SA (Abacus Diagnostica Oy) test. This test identified S. aureus but the presence of the mecA gene result was negative, and the isolate was reported as meticillin-sensitive Staphylococcus aureus (MSSA). Susceptibility studies were done using VITEK 2 AST-P588 susceptibility cards (bioMérieux). The strain was identified as MRSA by the VITEK 2 system, although oxacillin MIC was low (0.5 µg ml(-1)). In view of these results, the isolate was tested for the presence of the mecC gene by a specific PCR and was verified as MRSA carrying mecC. The emergence of this new mecA homologue could have important consequences for the detection of MRSA when routine PCR methods are used as an identification method or provisional detection of MRSA, as in the case reported in this article, because S. aureus carrying the mecC gene will be wrongly diagnosed as meticillin susceptible. Negative results must be interpreted with caution and should be followed by conventional culture, and antimicrobial susceptibility testing or detection of mecC gene by a specific PCR.

Epidemic population structure of extraintestinal pathogenic Escherichia coli determined by single nucleotide polymorphism pyrosequencing.

We have developed an MLST-based scheme for typing Escherichia coli isolates using pyrosequencing of single nucleotide polymorphic positions (SNP). The SNP sequences are converted into allelic patterns and analyzed using the same approach used for MLST analyses. We have tested the method in two unselected collections of clinical isolates of E. coli obtained from blood and urine cultures. The two collections had a similar structure, 25% of the profiles (representing 68% of the isolates) were common to both, and 62% of the profiles (nearly 20% of the isolates) were unique. The four major profiles accounted for 44% of the isolates, and among these the most frequent one was related to the pandemic ST131 clone. The method is easy to implement and might be useful for typing large microbial collections.