Genetic variation in Staphylococcus aureus coagulase genes: potential and limits for use as epidemiological marker

Abstract

To perform coagulase gene typing, the repeated units encoding hypervariable regions of the Staphylococcus aureus coagulase gene were amplified by the PCR technique; this was followed by AluI restriction enzyme digestion and analysis of restriction fragment length polymorphism (RFLP) patterns. In order to assess the discriminatory power of this typing method, 30 epidemiologically unrelated S. aureus strains which differed by their pulsed-field gel electrophoresis patterns were examined. Although 18 of the 30 strains had unique and unshared AluI RFLP patterns, there were only four observed patterns in the remaining 12 strains. This finding indicated that unrelated strains may share identical AluI RFLP patterns. To elucidate the degree of genetic variation in the C-terminus-encoding loci within the coagulase genes, the PCR products of these 12 strains were subjected to Taq polymerase-mediated sequencing. Sequence analysis confirmed the AIuI recognition sites in each of the four RFLP groups and demonstrated that AluI appears to yield the highest RFLP in restriction enzyme analysis. By their DNA sequences the majority of strains sharing common AluI groups could be clearly

Coagulase gene polymorphism of Staphylococcus aureus isolated from goat mastitis in Brazilian dairy herds

“…In the last few years, numerous molecular techniques have been used to identify and compare S. aureus subtypes. The coa gene amplification has been considered a simple and accurate method for typing S. aureus isolated from distinct sources (Goh et al 1992;Schwarzkopf and Karch 1994;Aarestrup et al 1995;Schlegelová et al 2003). According to Aarestrup et al (1995) this technique can be used in epidemiological investigations of S. aureus mastitis, because it is easy to analyse coagulase gene polymorphisms among a large number of strains and the multiple distinct polymorphic patterns generated.…”

“…The amplification of the coagulase gene (coa gene) is considered as a simple and accurate method for identifying and discriminating S. aureus strains (Goh et al 1992;Schwarzkopf and Karch 1994;Aarestrup et al 1995;Schlegelováet al 2003). Although the role of coagulase as a virulence factor is not clear the gene that codes it presents a polymorphic 3¢ end region, which is used for typing S. aureus isolated from distinct sources (Phonimdaeng et al 1990).…”

Combination of capillary electrophoresis, PCR and physiological assays in differentiation of clinical strains ofStaphylococcus aureus

“…Most probably, the single S. aureus 2 strains with different RFLP profile were isolated from a patient who was a S. aureus carrier before hospital admission. The present study as well as others (Goh et al, 1992;Schwarzkopf & Karch, 1994;Raimundo et al, 1999) method for the reliable and simple investigation of nosocomial outbreaks due to either methillicin-resistant S. aureus or methillicin-susceptible S. aureus infections. Additional tests, performed during this study and carried out by CA analysis of physiological properties of three bacterial strains (BIOLOG), confirmed the results received by molecular methods and revealed a close physiological connection of isolates S. aureus 1 and 16.…”

“…With the coagulase gene RFLP method, individual strains can be easily compared by both the number of PCR-amplified gene products and the sizes of their restriction enzyme digest fragments. Because of the heterogeneity in the repeated unit-encoding locus, the coagulase gene, as has been shown in many publications (Goh et al, 1992;Schwarzkopf & Karch, 1994;Hooker et al, 1999;Raimundo et al, 1999), is a potential target for type classification on the basis of sequence analysis. Furthermore, nucleotide sequencing here provides an additional source of typing and a highly specific epidemiological marker with high discriminatory value.…”

Comparison of Pulsed-Field Gel Electrophoresis and Coagulase Gene Restriction Profile Analysis Techniques in the Molecular Typing of Staphylococcus aureus

“…However, CRP analysis is much less discriminatory than PFGE in the case of non-SEA-E-producing isolates, and its results could therefore lead to the misjudging of the causes of some outbreaks (for example, outbreaks 4 and 5 in this study [ Table 1]). Thus, while CRP analysis has been used successfully in several epidemiological studies of S. aureus (9,13), one study has indicated that it is insufficient as a sole method for the typing of staphylococcal isolates (21). Nevertheless, by combining CRP analysis with other fast PCR-based analytical techniques such as protein A gene typing (6) or inter-IS256-PCR typing (5), this methodology may be able to meet the needs of health departments.…”