Microscopic agglutination and polyacrylamide gel electrophoresis analyses of oral anaerobic spirochetes

Characterization of new periodontal and endodontic isolates of spirochetes

Gas chromatographic analysis of cellular fatty acids (CFA), biochemical reactions, electrophoresis of soluble cellular proteins, as well as immunodiffusion were used to discriminate between 16 fresh spirochete isolates from periodontal and endodontic infections. CFA patterns were compared by the Hewlett Packard MIDI library to all available reference strains, and results of the biochemical tests were compared to VPI's records for treponemal strains. The electrophoretograms of soluble proteins of the fresh isolates were compared to those of previously well described strains of Treponema denticola, T. pectinovorum, T. vincentii, T. socranskii subsp. socranskii, T. socranskii subsp. paredis, T. socranskii subsp. buccale, and T. socranskii 04. Immunodiffusion was carried out by using adsorbed polyclonal rabbit antibodies to representative strains of the species mentioned. These methods separated most clinical strains from approved species strains, suggesting that new species had been isolated.

Population genetic analysis of oral treponemes by multilocus enzyme electrophoresis

Seventeen treponemes recently isolated from necrotic pulps, periodontal and periapical infections and 17 previously well characterized oral treponemal strains were analyzed by multilocus enzyme electrophoresis. Ten genetic loci were characterized on the basis of the electrophoretic mobilities of their enzymatic products. All loci were polymorphic. The average number of alleles per locus was 7.8. The genetic diversity among the electrophoretic types at each locus ranged from 0.624 to 0.836 with a mean genetic diversity per locus of 0.751. The 34 strains represented 34 electrophoretic types, constituting 6 main divisions (I-VI) separated at genetic distances greater than 0.75. Several of the previously characterized treponemes revealed multiple bands of enzyme activity at several loci, indicating that they were not pure. The characterized strains usually clustered within established species, whereas fresh clinical isolates overlapped species borders. There was a large genetic difference between some reference and clinical strains, indicating that the latter may contain undescribed species. Treponema socranskii and Treponema denticola strains clustered in distinct divisions (IV and V, respectively), with the exception of T. denticola strain FDC 51B2 and T. socranskii subsp. paredis strain VPI D46CPE1, both previously well described. This indicated that the taxonomic assignment of these 2 strains should be reconsidered.

Isolation and characterization of a 53 kDa major cell envelope protein antigen from Treponema denticola ATCC 35405

A major cell envelope protein was purified from the cell envelope fraction of Treponema denticola ATCC 35405 by ion exchange chromatography after extraction with Zwittergent 3-14. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a relative molecular mass of 53 kDa for this protein with a pI of 6.3-6.8. Amino acid analysis revealed that this protein contained high proportions of hydrophobic amino acids (40.4%), and no cysteine could be detected. The N-terminus of the protein was blocked to Edman degradation. Rabbit antiserum raised against the purified 53 kDa protein reacted with the outer envelope of the T. denticola cell surface as confirmed by immunoelectron microscopy. This rabbit antiserum reacted with 4 of the 11 strains of treponemes tested in this study. Sera from 9 to 18 periodontitis patients reacted strongly with this 53 kDa cell envelope protein of T. denticola as determined by immunoblotting analysis.

Spirochaetes in oral infections

Oral spirochaetes, which are small-, medium- or large-sized, include species of the genus Treponema, many of which have not yet been cultured. They are found in root canal infections, pericoronitis, gingivitis and periodontitis, constituting up to 10% of the flora in endodontic abscesses, 30% in acute necrotizing ulcerative gingivitis, and 56% in advanced marginal periodontitis. The strong proteolytic activity of these organisms probably make them causes of infection rather than consequences. Being able to penetrate tissue, they bring their enzymes, metabolic products, and endotoxins, in direct contact with target cells. This may perturb essential functions of host cells and immunoglobulins. Enzyme activities may also help fulfil the complex growth requirements of spirochaetes in vivo. Reaction between infected periodontal tissue and monoclonal antibodies to Treponema pallidum has suggested that uncharacterized pathogen-related oral spirochaetes have surface structures and functions analogue to this well recognized pathogen. This warrants a more intensified search for the role of spirochaetes in oral infections.

A common antigen of Treponema denticola and other Treponema species detected by monoclonal antibody

Murine monoclonal antibodies against Treponema denticola were produced. One monoclonal antibody (MSA257) reacted with 34,000 dalton antigens of all T. denticola strains, including ATCC strains and our isolates. This monoclonal antibody also reacted with antigens of other treponema strains tested.

Protein patterns, serotyping and plasmid DNA profiles in the epidemiologic fingerprinting of Pseudomonas aeruginosa

The epidemiological typing schemes based on serotyping, antibiotic susceptibility pattern, plasmid DNA profile, and protein patterns determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) were evaluated for their usefulness in typing clinical isolates of Pseudomonas aeruginosa. The serotypability was lower (45%) than reported in the literature (85-95%). The most commonly found serotypes were O:1 (19%), O:11 (25%), O:6 (35%). The electrophoretic analysis of plasmid DNAs showed plasmids (molecular weight = 1 to greater than 40 megadaltons). Two plasmids of Mr 2 and 38 megadaltons were found in various serotypes. The restriction enzyme analysis of plasmid DNA showed identical DNA fragment patterns among distinct serotypes. The SDS-PAGE protein banding patterns of whole-cell proteins showed homogeneity among the strains. However, analysis of the soluble protein patterns of the strains showed sufficiently distinct protein profiles that can be used to differentiate between various strains. The results of this study demonstrate that the electrophoretic patterns of soluble proteins, in combination with plasmid DNA profile or serotyping, can be of value in the epidemiologic fingerprinting of clinical isolates of Pseudomonas aeruginosa.

Protein fingerprinting for the determination of relatedness in Acinetobacter calcoaceticus subspecies anitratus isolated from patients in a surgical intensive care unit

The use of protein fingerprinting for the establishment of relatedness among isolates of Acinetobacter calcoaceticus subspecies anitratus, isolated from patients in a surgical intensive care unit was examined. Polyacrylamide gel electrophoresis was used to analyze the cellular proteins from whole cell lysates of 14 intensive care unit A calcoaceticus subspecies anitratus isolates and 11 control strains. Antimicrobial susceptibilities and plasmid profiles were also determined for all isolates. All intensive care unit A calcoaceticus subspecies anitratus isolates exhibited identical cellular protein fingerprints, no detectable plasmids, and minimum inhibitory concentrations within +/- 1 log2 dilution of the mode value for each of the antimicrobial agents tested. The other clinical isolates demonstrated a range of antimicrobial susceptibilities, various numbers and sizes of plasmids, and distinctly different protein fingerprints. These data indicate that protein fingerprinting may be useful as an epidemiologic tool in A calcoaceticus subspecies anitratus outbreaks and this method deserves further study.