Correction: Higher Prevalence and Abundance of in the Human Gut of Healthy Subjects. - Valerio Iebba; Floriana Santangelo; Valentina Totino; Mauro Nicoletti; Antonella Gagliardi; Riccardo Valerio De Biase; Salvatore Cucchiara; Lucia Nencioni; Maria Pia Conte; Serena Schippa (PLoS ONE, 2013)