SRST2 analysis of sequence types and beta-lactamase CTX-M-15 genes among hospital isolates. Rates of isolation of different sequence types (STs), coloured by CTX-M-15 status, as determined by SRST2 run with default parameters on a public data set of strains from a single hospital. In each species, a single known ST dominates the population (highlighted) and is also the dominant source CTX-M-15 genes. next to an ST indicates a match to the closest defined ST; that is, that for all seven loci the closest known allele is the one belonging to that ST, however at ?1 these loci there is an imprecise match (SNP or indel) compared to the known allele sequence. `Novels indicates a novel sequence type resulting from a combination of known alleles, with precise matches at all loci (`NF in SRST2 output); `Novel indicates a novel combination of alleles, with ?1 of those alleles being novel itself (that is, with no exact match in the MLST database) (`NF in SRST2 output).