Discrimination between oral streptococci by pyrolysis gas-liquid chromatography

Abstract

Washed organisms, including strains of Streptococcus mitior, S. mutans, and S. sanguis, were examined by curie-point pyrolysis gas-liquid chromatography. A linear discriminant function based upon three items from the output data was adequate for segregating the strains according to species. Strains with intermediate properties were also encountered. Sources of variability in cultures were evaluated, chromatographic performance was maintained throughout the investigation, and matching performance from a duplicate pair of chromatographic columns was demonstrated.

Pyrolysis Gas Chromatography of Pseudomonas and Acinetobacter Species

“…Several other workers have commented on the problem of column deterioration (Quinn 1974;Meuzelaar et al 1975;Needleman & Stuchbery 1977). Although Stack et al (1978) managed to maintain a single column over long periods by periodically re-packing the upper end, and although contamination of the Curie-point pyrolyser with tar-like substances may be reduced by using disposable quartz tubes, gradual deterioration is inevitable. With Py-GC, this deterioration is more rapid than with conventional gas chromatography, since most pyrolysis units allow some air into the system with each specimen change, and the wide range of materials in the bacterial pyrolysate are likely to include some that react with the column.…”

“…This problem has been admitted by some other workers (Reiner & Ewing 1968;Meuzelaar & Kistemaker 1973;Sekhon & Carmichaell973) and would seem to be a fundamental drawback of the present technique. Haddadin et al (1 973), however, claim to have obtained reproducible results with Vibrio species using a second pair of columns, and Stack et al (1978) achieved good intercolumn reproducibility over several pairs of columns for Py-GC of streptococci. The reasons for the different pyrogram patterns we obtained with different columns remain unexplained, but may have been due to chemical reaction between components of the complex pyrolysate and the stationary phase.…”

“…Although some workers have achieved good intercolumn reproducibility with Carbowax 20M (Haddadin et d. 1973;Stack et al 1978) the fundamental drawbacks of this stationary phase are a serious barrier to successful Py-GC of micro-organisms, especially if inter-laboratory reproducibility is to be achieved. Although the great majority of previous workers have used Carbowax 20M, there appears to be no particular reason why this phase has been selected.…”

A laboratory microcosm (artificial mouth) for the culture and continuous pH measurement of oral bacteria on surfaces

“…'Streptococcus mitior' LPA-1 (Stack et al 1978) was obtained from H. Luoma, Department of Dentistry, University of Kuopio, Finland. Originally regarded as a strain of Strep.…”

The Application of Pyrolysis Techniques to the Identification of Micro‐organisms

“…Curie-point pyrolysis has not often been applied to micro-organisms but this probably reflects the unavailability of suitable commercial equipment. Stack et al (1977) have successfully used the technique for the differentiation of oral streptococci using a low power commercial system but Meuzelaar & in't Veld (1972) developed a system for Curie-point pyrolysis of complex biological samples based on a specially designed pyrolysis reactor. Certain of the products formed by pyrolysis above 600 OC have such high boiling points that they tend to condense in a unit held at 15OOC before they are swept onto the analytical column.…”