Figure 1: (a) Microarray oligonucleotide probes layout. Oligonucleotides 1 to 222 are provided in Tables 2 and 3. P represents S. pneumoniae housekeeping genes and 16S rDNA positive control oligonucleotides. N indicates negative control oligonucleotides designed from housekeeping genes of other bacterial species. E denotes empty spot. (b) Scanned microarray images of S. pneumoniae genomic DNA hybridized with 6 samples (serotype 3, 9V, 11A, 19F, 22F and 22A). The numbers correspond to the spot identifiers given in Tables 2 and 3, and Figure 1(a) P indicates positive spot.