Partial purification and characterization of the multiple molecular forms of staphylococcal clotting activity (coagulase)

Isolation, purification, and characterization of staphylocoagulase, a blood coagulating protein from Staphylococcus sp. MBBJP S43

Staphylocoagulase, a protein produced by S. aureus, play major role in blood coagulation and investigations are in advance to discover more staphylocoagulase producing species. The present study demonstrates the identification of a coagulase producing bacteria and isolation, purification and characterization of the protein. The bacteria was identified using 16S rDNA sequencing and phylogenetic investigation, classified the bacteria as Staphylococcus sp. MBBJP S43 with Genbank accession number KX907247. Tube test and Chromozym TH assay were used to study enzyme activity and comparison was made with five standard coagulase positive strains. The SEM images of the fibrin threads provide evidence of coagulation. The optimum temperature for enzyme activity was 37°C and pH of 6.5-7.5. Glucose and lactose as a carbon source and ammonium chloride as nitrogen source greatly influenced the bacterial growth. Staphylocoagulase has been purified to homogeneity (766 fold) by 80% (NH₄)₂SO₄ precipitation, Sephadex G-75 gel filtration, DEAE anion exchange chromatography, and HPLC using C18 column. SDS PAGE revealed the molecular weight of the protein to be approximately 66kD and FTIR spectra of the purified protein demonstrated the presence of α helical structure. Present study revealed that the Staphylococcus sp. MBBJP S43 strain is a potential staphylocoagulase producing bacteria.

Molecular typing of methicillin-resistant and methicillin-susceptible Staphylococcus aureus isolates from Shiraz teaching hospitals by PCR-RFLP of coagulase gene

BACKGROUND AND OBJECTIVES

To investigate coagulase gene polymorphism of MRSA and MSSA isolates from Shiraz teaching hospitals from 2011 to 2012.

MATERIALS AND METHODS

A total of 302 isolates of Staphylococcus aureus were collected from clinical specimens in three major teaching hospitals and confirmed on the basis of morphological characteristics and biochemical tests. The isolates were subjected to molecular typing on the basis of coagulase enzyme gene polymorphism by PCR-RFLP.

RESULTS

There were 27 and 28 different RFLP patterns for AluI and HaeIII restriction enzymes respectively. This study showed that the discriminatory power of coagulase gene typing by Hae III enzyme was more than that of Alu I enzyme.

CONCLUSION

PCR-RFLP method is rapid, reproducible, simple and efficient for typing Staphylococcus aureus isolated from clinical specimens. This study showed that Hae III discriminatory power is better than Alu I for typing Staphylococcus aureus isolates.

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

Fast, sensitive and cheap determination of pathogenic bacteria is extremely important in many branches, for example biotechnology, quality control, analysis of samples and antimicrobial therapy. The development and application of analytical techniques in practice could provide new possibilities in this regard. The bacterial pathogen Staphylococcus aureus is responsible for a significant amount of human morbidity and mortality. Rapid and sensitive determination is therefore very important. In the present study, novel methods, based on capillary zone electrophoresis and (as confirmation of these results) molecular analysis of a part of the coag gene, were developed for identification and differentiation of three S. aureus strains. The electrophoretic measurements rely on the differential mobility of bacteria in the fused silica capillary under the direct current electric field. To perform coagulase gene typing, the repeated units encoding hypervariable regions of the S. aureus gene were amplified using the PCR technique followed by restriction enzyme digestion and analysis of restriction fragment length polymorphism patterns as well as sequencing. Finally, the results of electrophoretic measurements with molecular analysis were compared.

Improved application of the oscillating method for the isoelectric point determination of protein: Potential connection with protein data banks

The oscillating method (OM) for the theoretical determination of the pI values, one by one, of proteins and other macromolecules has been previously published [Sillero and Maldonado, Comput. Biol. Med 36 (2006) 157-166]. An improved application of the method, here named as improved oscillating method (IOM), allows the pI determination of group of proteins. This characteristic may be useful to explore the pI value and electric charge of family of enzymes. As an example the pI values of 1630 enzymes collected in a Swiss-Prot data bank (www.expasy.org), as belonging to the enzymes ligases (EC 6. 2. 1. *) is presented. The method also permits the determination of the pI value of any group of proteins stored in data banks provided that they can be supplied to the program in a FASTA format. Free access to IOM can be reached at http://www.bq.uam.es/otros/pical3.zip.

Isoelectric point determination of proteins and other macromolecules: oscillating method

A program written in Visual Basic has been developed to calculate the isoelectric point of proteins and other macromolecules bearing acid-basic residues. The pI value can be theoretically calculated with the precision required. The computer automatically supplies a representation of the charge of the protein versus pH values. The corresponding values can also be obtained, on command, in the form of table.

Molecular epidemiology of methicillin-resistant Staphylococcus aureus strains: state of affairs and tomorrow' s possibilities

Methicillin-resistant strains of Staphylococcus aureus (MRSA) have posed a clinical threat for nearly 40 years. During these years, an array of additional technologies suited for identification of MRSA below the species level has become available. The technologies, whether they assess phenotype or genotype, provide data that can be used for elucidation of the routes of dissemination of individual MRSA types. This review summarizes the current state of affairs with respect to the quality of the various laboratory techniques and includes descriptions of novel strategies such as binary typing and multilocus sequence typing (MLST). Drawbacks of procedures will be compared, and the value of molecular typing in the elucidation of complex biological phenomena, such as epidemicity, carriage, and reduced vancomycin susceptibility, will be indicated. Means for integrated assessment of bacterial biology, epidemiology, and population structure will be discussed.

N-terminal sequence polymorphism in the coagulase gene of Staphylococcus aureus and its potential use as an epidemiological marker

N-terminal DNA sequences of the coagulase gene were amplified from Staphylococcus aureus strain ISP8 (NCTC 8325-4) DNA using the polymerase chain reaction. The amplified DNA product (984 bp) was used to probe SmaI and DraI digested total DNA of methicillin- and multi-resistant S. aureus (MRSA) type strains, methicillin-sensitive S. aureus (MSSA) clinical isolates, and community (commensal) isolates. A SmaI fragment of a similar size in all the isolates examined hybridized with the coagulase gene fragment probe. All MRSA isolates, representing closely related (clonal) types, revealed identical coagulase hybridization patterns with DraI digested DNA. MSSA and community isolates closely related to ISP8 by SmaI fragment analysis shared closely related DraI/coagulase hybridization patterns, differing from that identified for the MRSAs. In contrast, the community and MSSA isolates not related to ISP8 as judged by total SmaI fragment polymorphisms, were also diverse in their DraI/coagulase hybridization patterns. In addition, the intensity of the hybridization signal obtained with the MRSA isolates varied significantly (less than) from the other isolates, indicating the presence of multiple and probably different coagulase genes between the isolates. The findings reported here indicate that hybridization analysis using single genes as DNA probes is less discriminant than restriction fragment length polymorphism analysis of the total genome of different isolates.

Molecular typing of Staphylococcus aureus on the basis of coagulase gene polymorphisms

Staphylocoagulase, a major phenotypic determinant of Staphylococcus aureus, exists in multiple allelic forms, in part because of the existence of gene variants within the 3'-end coding region. This region contains a series of repeating 81-bp DNA sequences which differ both in the number of tandem repeats and the location of AluI restriction sites among different isolates. Utilizing this finding, we developed a novel typing method for S. aureus based on polymerase chain reaction amplification of the variable region of the coagulase gene followed by AluI restriction enzyme digestion and analysis of restriction fragment length polymorphism (RFLP). Among 30 S. aureus isolates studied initially, a total of 10 distinct RFLP patterns were observed. There was excellent correlation of the RFLP patterns with typing of these isolates by multilocus enzyme electrophoresis at 20 chromosomal loci. This coagulase RFLP method was used to analyze an additional 39 S. aureus isolates and successfully traced the source of an outbreak of methicillin-resistant S. aureus infections at a local hospital.

Evidence for three different fibrinogen-binding proteins with unique properties from Staphylococcus aureus strain Newman

Binding of extracellular components of Staphylococcus aureus strain Newman to fibrinogen and prothrombin was investigated. Affinity-purified material from fibrinogen- and prothrombin-Sepharose was analysed on immunoblots, and two proteins with coagulase activity were identified. The two coagulases were produced in a sequential manner during staphylococcal growth. An 87 kDa fibrinogen-binding coagulase was produced mainly during the exponential growth phase and was replaced by a 60 kDa fibrinogen- and prothrombin-binding coagulase which was produced mainly during the post-exponential growth phase. In addition, a 19 kDa fibrinogen-binding protein was constitutively produced. Analyses of immunogenic properties and NH2-terminal sequences suggested that the 19, 60 and 87 kDa fibrinogen-binding proteins are not closely related. The NH2-terminal sequence of the 87 kDa protein is identical to a previously described coagulase from Staphylococcus aureus strain 8325-4. The 19 kDa fibrinogen-binding protein, which spontaneously aggregates into dimers and larger molecular weight complexes, had a unique NH2-terminal sequence.

Comparison of compact colony-forming activity and paracoagulation activity of strains of Staphylococcus aureus in serum and plasmas of various animals

Using 20 strains of Staphylococcus aureus isolated from clinical specimens, the compact colony-forming activity (CCFA) in serum-soft agar (SSA) in sera from various animals and the paracoagulation (PC) activity of the compact colony-forming active substance (CCFAS) extracted from these strains were investigated. The results of this comparative study revealed that the CCFA and PC of S. aureus for sera from various animals in SSA were different, not only among different strains but also in the same strains. In addition, the effect of galactose and calcium ions on the PC activity of these strains in experiments employing human fibrinogen permitted the recognition of these groups of S. aureus strains. In one group, PC activity was decreased by galactose but unaffected by calcium ions, in the second group PC activity was unaffected by galactose but increased by calcium ions, while in the third group it was unaffected by both. These results suggest the possibility of heterogeneity of CCFA among different strains of S. aureus.

Biochemical properties of fibrinogen binding protein (clumping factor) of the staphylococcal cell surface

The staphylococcal fibrinogen binding protein of a strain of coagulase-negative Staphylococcus aureus was purified 229 fold in terms of the haemagglutination unit compared to the starting material by affinity chromatography on fibrinogen-Sepharose. By polyacrylamide gel electrophoresis in both reduced and unreduced gels, the protein showed one major band and minor bands with relative molecular masses of 62,000, 61,000, and 59,000, respectively. The isoelectric point was between 10.2 and 10.8 determined by isoelectric focusing in polyacrylamide gel. By the agar diffusion test one band was obtained against anti-whole cell rabbit serum. Amino acid analysis of fibrinogen binding protein showed glycine, glutamic acid, lysine, alanine, aspartic acid, and arginine as the major components. Protein A or teichoic acid extracted from the homologous strain did not show fibrinogen binding activity assayed by haemagglutination and anti-fibrinogen binding activity of anti-whole cell Fab. The amount of the fibrinogen binding protein to absorb the activity of anti-whole cell Fab was decreased to 1/60 of that of the starting material. Sheep red blood cells coated with the fibrinogen binding protein agglutinated in 0.001% (w/v) fibrinogen solution.

Presence of toxic shock toxin in toxic shock and other clinical strains of Staphylococcus aureus

Toxic shock toxin (TST), also known as pyrogenic exotoxin C (Schlievert et al., J. Infect. Dis. 143:509-516, 1981) and staphylococcal enterotoxin F (Bergdoll et al., Lancet i:1017-1021, 1981), was purified from toxic shock strains of Staphylococcus aureus by preparative isoelectric focusing and by chromatofocusing. Neither method produced an absolutely pure protein as determined by silver staining of sodium dodecyl sulfate-acrylamide gels, although chromatofocusing was the better method of the two. Three molecular weight variants of the protein were found in the two toxic shock syndrome strains that were studied, regardless of the purification method that was used. An isoelectric point of 7.15 and molecular weights of 21,400, 22,100, and 23,200 were determined for the different forms of the protein from electrophoresis data. A sedimentation coefficient of 2.3S was determined by sucrose gradient centrifugation, and a Stokes radius of 2 X 10(-7) cm was determined by gel filtration. An average molecular weight of 18,900 for all of the TST forms was calculated from these data by the Stokes-Einstein equation. A survey for TST in 32 control and 46 toxic shock strains of S. aureus by isoelectric focusing and by agarose gel double immunodiffusion with specific rabbit antiserum revealed that the isoelectric focusing method tends to overestimate the number of TST-positive strains because of the detection of non-TST, neutral staphylococcal proteins. Based on immunodiffusion data, the association of TST with toxic shock strains was found to be 100% in vaginal isolates and 62% in non-vaginal isolates. In the control strains, TST was found in 16% of the vaginal strains and 23% of the non-vaginal strains. The value of this toxin as a marker for toxic shock and its relationship to the pathogenesis of this disease are discussed.