ehu.es/PCR. Briefly, a colony of each isolate was suspended in 20 μL of TE buffer (10 M Tris-HCl, 1 M EDTA pH 
with 0.9% NaCl,
and after heating at 98°C for 10 min, the suspension (5 μL) was used as a template for PCR using the BioredMix (BioLine, London, UK) system and the primers (10 μM) tuf-g (5′-GGTGTACCAGCATTAGT-3′), tuf-a (5′-TTCAGTATGTGGTGTAA-3′) and tuf-e (5′-TTCGTGCATACCGATGA-3′). The Ferrostatin-1 price primer pairs tuf-g/tuf-e and tuf-g/tuf-a result in a 370 bp (S. epidermidis) or a 530 bp (S. aureus) fragment [see additional file 2]. PCR conditions were 1 cycle of 94°C for 5 min, 30 cycles of 94°C for 1 min, 48°C for 1 min, and 72°C for 2 min, and a final extension of 72°C for 5 min. Identification of the isolates was confirmed by PCR sequencing of a 470 bp fragment of the 16S rRNA gene using primers and conditions previously described
[33]. The amplicons were purified using the Nucleospin®Extract II kit (Macherey-Nagel, Düren, Germany) and sequenced at the Genomics Unit of the Universidad Complutense de Madrid, Spain. Genotyping ofS. epidermidisisolates by pulsed field gel electrophoresis (PFGE) To determine the diversity ofS. epidermidisin breast milk in mastitis infections, 200 isolates of this species obtained from 26 women with mastitis were subjected to PFGE genotyping together with 105 isolates of the same species obtained from breast milk of 12 healthy women
within the same period of time [34] (Table1). Chromosomal Rucaparib manufacturer DNA was selleck digested with the endonucleaseSmaI (New England Biolabs, Ipswich, MA) at 37°C for 16 h. Electrophoresis was carried out in a CHEF DR-III apparatus (Bio-Rad Laboratories, Hercules, CA) for 23 h at 14°C at 6 V cm-1with pulses from 5 to 50 s. A standard pattern (Lamda Ladder PFG Marker, New England Biolabs) was included in the gels to allow comparison of the digitally normalized PFGE profiles. Computer-assisted analysis of the gels was performed with the Phoretix 1D Pro software (Nonlinear USA, Inc., Durham, NC). PFGE profiles differing in one or more fragments were considered different. Cluster analysis of the PFGE patterns was performed using the UPGMA method based on the Dice similarity coefficient. Screening for potential virulence this website determinants On the basis of the different PFGE profiles, 76 strains (40 from mastitis cases and 36 from healthy women) were further selected and characterized. Presence of genesembp,fbe,atlE andicaD, which respective products are involved in adhesion and biofilm formation, was evaluated using primers couples described previously [7,35–37]. In the case offbe,atlE andicaD, a multiplex PCR format was designed using the following conditions: 5 min at 94°C followed by 30 cycles of 94°C for 1 min, 60°C for 30 s, 72°C for 1 min and, then, a final extension of 5 min at 72°C [see additional file 3].