Fig. (3b) shows: PCA plots based on DGGE profiles of 16S rRNA gene PCR-derived amplicons of caecum samples collected from eleven-week-old female BALB/cj mice. The light-blue (O) groups received oral exposure to Vancomycin from drinking water ad libitum. The red (IN) received vancomycin 0.21 mg/35µl nasally by i.n.for 2x5 days. The blue PBS group received PBS 35µl nasally by i.n. 2x5 days. DGGE: denaturing gradient gel electrophoresis after DGGE-PCR: polymerase chain reaction.