Combined Use of Ribotyping, PFGE Typing and IS431 Typing in the Discrimination of Nosocomial Strains of Methicillin‐Resistant Staphylococcus aureus

Abstract

We have previously reported the phenotypic characterization of methicillin-resistant Staphylococcus aureus (MRSA) clinical strains isolated in Malaya University Hospital in the period 1987 to 1989 using antibiogram, coagulase typing, plasmid profiles, and phage typing. Here, we report the analysis of the same strains with three genotyping methods; ribotyping, pulsed-field gel electrophoresis (PFGE) typing, and IS431 typing (a restriction enzyme fragment length polymorphism analysis using an IS431 probe). Ribotyping could discriminate 46 clinical MRSA strains into 5 ribotypes, PFGE typing into 22 types, and IS431 typing into 15 types. Since the differences of the three genotyping patterns from strain to strain were quite independent from one another, the combined use of the three genotyping methods could discriminate 46 strains into 39 genotypes. Thus, the powerful discriminatory ability of the combination was demonstrated.

Coordinated phenotype switching with large-scale chromosome flip-flop inversion observed in bacteria

“…PFGE with SmaI-cut genomic DNA was carried out as described previously (37), using a CHEF DRII apparatus (Bio-Rad Laboratories) with an electric field strength of ∼6 V/cm and a pulse time of 20 s for 22 h. To differentiate the restriction profile of the genomes of Mu50Ω1 from Mu50Ω2, enzyme AscI or SgrAI was used for DNA digestion. Southern blotting hybridization was carried out as described previously (37). The DNA probe was prepared using primers SAV0813-Fp22 (5′-TTAACTAT-GAGCACGCTATT-3′) and SAV0813-Rp468 (5′- The probes were then labeled with digoxigenin using a DNA labeling kit (Roche).…”

Cell Wall Thickening Is a Common Feature of Vancomycin Resistance in Staphylococcus aureus

“…PFGE was carried out as described previously (35). Electrophoresis was performed for 22 h with a DRII contour-clamped homogenous electric field apparatus (Bio-Rad) with a pulse time of 5 to 40 s. The separated DNA fragments digested with the enzyme SmaI were photographed after being stained with ethidium bromide.…”

Epidemiologic Typing of Methicillin‐Resistant Staphylococcus aureus in Neonate Intensive Care Units Using Pulsed‐Field Gel Electrophoresis

“…Ichiyama et al reported that MRSAs with several different PFGE patterns were isolated from patients in individual hospitals (15). Yoshida et al suggested that local outbreaks could well be monitored by the combination of PFGE typing and other genomic typing with sufficient resolution power as well as satisfactory references to the biological and evolutionary features of each MRSA isolate (29). Although there was no contact between JMSH, DMSH and SUH personnel and of the distant geographic locations from each other, MRSAs with similar or the same PFGE patterns were isolated from neonates in the NICUs of these hospitals.…”