title: Typing of Staphylococcus aureus strains by PCR-amplification of variable-length 16S-23S rDNA spacer regions: characterization of spacer sequences.
abstract: To develop a rapid and accurate method of typing large numbers of clinical isolates of Staphylococcus aureus, the spacer region C of the rRNA operon [1391-507 (16S-23S)] was enzymically amplified from 322 strains. When the products were separated by denaturing PAGE, 15 variable-length rrn alleles were demonstrated, ranging in size from 906 to 1223 bp. The variable-length HpaII-digested region C [(region E; 1446-196 (16S-23S)] amplification products were cloned into M13mp18RF to sequence separate variable-length alleles. A total of 17 region E inserts were sequenced, aligned and divided into nine alleles by length (938-1174) and sequence properties. The 16S-23S spacer rDNA varied in length (303-551 bp) and in properties; three alleles contained a tRNAIle gene alone, two alleles contained a tRNAIle and a tRNAAla gene, and four alleles lacked tRNA genes. The sequences of two alleles showed less than 1% variation when isolated from two or three S. aureus strains. The 48 penicillin- and methicillin-sensitive strains were divided into 26 ribotypes; in contrast, the 274 methicillin-resistant S. aureus (MRSA) strains were divided into nine ribotypes (A-I) with 97% typing as either ribotype A or B (rrnL was missing in B). The sequence conservation of the rrn operons argues for the use of the 16S-23S spacer region as a stable and direct indicator of the evolutionary divergence of S. aureus strains.
authors.affiliation: Department of Microbiology, Heidelberg Repatriation Hospital,Heidelberg West 3081, Victoria,Australia.
authors.forename: Volker
authors.initials: V
authors.lastname: Grtler
authors.affiliation: Department of Microbiology, Heidelberg Repatriation Hospital,Heidelberg West 3081, Victoria,Australia.
authors.forename: Helen D
authors.initials: HD
authors.lastname: Barrie
mesh_terms: D000483:Alleles; D001483:Base Sequence; D017931:DNA Primers; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics*; D005798:Genes, Bacterial; D006801:Humans; D016106:Methicillin Resistance / Q000235:genetics; D008969:Molecular Sequence Data; D010403:Penicillin Resistance / Q000235:genetics; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000379:methods*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012338:RNA, Ribosomal, 23S / Q000235:genetics; D012360:RNA, Transfer, Phe / Q000235:genetics; D015203:Reproducibility of Results; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D013211:Staphylococcus aureus / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D017931:DNA Primers; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D012338:RNA, Ribosomal, 23S; D012360:RNA, Transfer, Phe