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We formulated a chemically defined medium consisting of 14 inorganic salts, 23 amino acids, 23 vitamins and other factors, seven purines and pyrimidines, and glucose which would successfully support the growth of a wide variety of oral microorganisms. Of 204 oral isolates representing 20 genera and 60 species, 197 maintained viability through six serial transfers.
Microorganisms of the Mycoplasma genus were found in the washing fluids of the oral cavity in 2% of healthy youths, and in 57.1% of patients with parodontal lesions: 25.7% in the buccal fluid, 17.1% in the dental tartar and 34.2% in the gingiva exsudate. Microplasma was not found in dental caries and in the radicular canals with pulpar gangrene. Although these microorganisms were frequently found in subjects with parodontal lesions they cannot be implicated with certainty in their aetiology.
Studies performed since the early, 1970s have yielded tremendous amounts of information about the physiology, genetics, and interactions of oral bacteria. This pioneering work has provided a solid foundation to begin to apply the knowledge and technologies developed using suspended populations for studying oral bacteria under conditions that more closely mimic conditions in the oral cavity, in biofilms. Our current understanding of phenotypic capabilities of individual and complex mixtures of adherent oral bacteria is in its infancy. There is ample evidence that oral streptococci have different patterns of gene expression than planktonic cells, but we have little understanding of the basis for these observations. Even in biofilmforming bacteria with very well-developed genetic systems it is only very recently that genetic loci involved in biofilm formation and responses to surface growth have been identified. A comprehensive study of the physiology and gene expression characteristics of adherent oral bacteria not only will enhance our abilities to control oral diseases, but it will provide critical information that can be applied to a variety of other pathogenic microorganisms.
In the present study, we examined the in vitro effect of low concentrations of ascorbic acid (lower than normal plasma levels), on the adherence of five microbial strains (Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Pseudomonas aeruginosa) to human buccal epithelial cells (BEC) of healthy volunteers. The study reached the following conclusions: 1) the presence of ascorbic acid significantly reduces the ability of all tested strains (with the exception of Klebsiella pneumoniae) to adhere to BEC; 2) ascorbic acid interacts with the epithelial cells and decreases the adherence of all tested microorganisms. These findings may be of potential clinical significance.
The influence of experimental neutropenia on the wound healing process in standardized excisional palatal wounds was studied in 16 guinea pigs. Corresponding wounds in 15 normal animals were used as controls. Neutropenia was induced and maintained by daily injections of heterologous anti-neutrophil serum. One-micron sections from biopsies of palatal mucosa sampled 6, 24, 48 and 120 h after wounding were evaluated with special reference to the progress of epithelial wound repair and to the occurrence and location of inflammatory cells and bacteria. In animals treated with anti-serum, neutrophilic leukocytes disappeared from the wound cavity, whereas other inflammatory cells remained unchanged. Further bacterial invasion deep into the cavity was observed. The epithelial repair took place at a deeper level in the wounds of neutropenic animals compared with those of normal animals. The rate of re-epithelialization was the same in neutropenic and control wounds. The experiment indicates that the neutrophils in oral wounds provide a principal agency for host defense against microorganisms and probably thereby indirectly determine the direction and level of epithelial cell migration.
Secretory immunoglobulin A is the predominant immunoglobulin in labial minor salivary gland secretions. Its mean concentration is four times higher in these secretions than in parotid gland secretion. The minor salivary glands can produce 30 to 35 percent of the immunoglobulin A that enters the oral cavity. This, together with the potential accessibility of these glands to antigenic stimulation, suggest that they may be an important source of the immune factors that are involved in the regulation of the microorganisms in the oral environment.
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Cephalic tetanus is a localized form of tetanus. As in generalized forms, trismus is a prominent feature of the disease, leading to considerable difficulty in feeding, swallowing of the saliva and mouth hygiene. These difficulties often precede respiratory problems and aspiration bronchopneumonia is a frequent life-threatening complication. Muscle relaxants other than curare drugs may show a limited benefit for relieving trismus. Tetanospasmin, the tetanic neurotoxin, and botulinum toxin share many similarities, having a closely related chemical structure, an origin from related microorganisms (Clostridium tetani and Clostridium botulinum, respectively), and presumably, the same mechanisms of action in the neuron. The difference between the two lies in their peculiar neurospecificity, acting in different neurons. Injection of minute doses of botulinum toxin in the muscles involved in focal dystonias or other localized spastic disorders have proved to be very effective in these conditions. We describe the use of botulinum toxin A in the successful treatment of trismus in a patient suffering from cephalic tetanus. We believe that this form of treatment may be of value in lowering the risk of pulmonary complications in tetanic patients.
Chronic pharyngitis is an usual process with difficult treatment. It has been related to tonsillectomy. This study collected 224 patients suffering from chronic pharyngitis, 55 tonsillectomies and 169 without operation. Bacteriological culture was done from nasopharynx in the different seasons. Microorganisms more frequent were Staphylococcus aureus, Corynebacterium sp and Aspergillus. The time between the tonsillectomy and this study has been of more than 17 years. No relationship has been found between chronic pharyngitis and tonsillectomy, considering types of microorganisms, seasons, numbers of microorganisms isolated per culture, Gram stain, and age of the patients.
This study was performed to investigate the presence of microorganisms in the epithelial cells of leukoplakia. Frozen sections of 20 specimens of leukoplakia were stained with DNA-binding bisbenzimide Hoechst 33258. As a control, 20 specimens of normal oral mucosa and five specimens of normal skin were used. In all preparations of leukoplakia, small granular fluorescing structures were observed within the cytoplasm of the epithelial cells, predominantly within the cytoplasm of prickle cells, although the amount of the granular structures varied between specimens, layers of the epithelium and even areas of the epithelium within a single section. Less granular structures were observed, or none at all, in the cytoplasm of the epithelial cells of normal mucosa. No structures were observed in the cytoplasm of the epithelium of skin. The results in this study strongly suggest that microorganisms are present in the epithelial cells of oral mucosa, and that they are closely associated with the development of oral leukoplakia. It is postulated that the microorganisms in the epithelial cells could be bacteria, particularly mycoplasmas.
Taurolin, a non-antibiotic antimicrobial agent, significantly reduced the adherence of buccal and vaginal strains of Candida albicans blastospores and urine isolates of Escherichia coli and Staphylococcus saprophyticus to epithelial cells. Light microscopy and radio-isotopic counting methods were used to quantify the adherence of the micro-organisms to either uroepithelial or buccal epithelial cells. A maximum reduction in adherence of approximately 65% was obtained. The anti-adherence capacity was time-dependent, requiring a contact time of 30 min to achieve maximum effect. Taurolin at sub-minimum inhibitory concentrations (MIC) significantly reduced the adherence of Candida and E. coli. A concentration slightly higher than the MIC was required for Staph. saprophyticus. Treatment of either epithelial cells or micro-organisms with Taurolin resulted in reduced adherence of microorganisms.
A new, improved agar medium for the isolation of Streptococcus mutans, the etiological agent of dental caries, was developed. In contrast to mitis-salivarius agar, this medium not only recovers a greater number of S. mutans strains from most oral specimens but, because of its mannitol and sorbitol content, it also facilitates the differentiation of S. mutans from other oral streptococci, e.g., S. salivarius, S. mitis, and S. sanguis, which do not grow or produce scanty growth only after 10 days of incubation. The medium is easy to prepare because of its simple and unique composition, is characterized by the presence of an acid indicator, and can be utilized under aerobic and anaerobic conditions as well. The medium cannot be used to distinguish among the eight serotypes, a to g and SL-1, of S. mutans. Mannitol-utilizing bacteria such as streptococci (e.g., S. faecalis) and other microorganisms (e.g., Staphylococcus aureus) are able to grow on this medium and can be distinguished from S. mutans by their unique colony morphology.
The purpose of this investigation was to find the relationship between the occurrence of Candida species and mutans streptococci at 7 sites (saliva, tongue, mucosa, teeth, clasp, external, and mucosal denture surfaces) in the mouth of 97 elderly persons (males: 43, age: 76.4 +/- 6.7 years; females: 54, age: 75.0 +/- 6.6 years). Among the subjects, there were complete denture wearers (n = 20), partial denture wearers (n = 45), and non-denture wearers (n = 32). Candida species were more significantly (p < 0.001) predominant in complete and partial denture wearers (80% each) than in non-denture (18.8%) wearers. The presence of Candida was highest on the mucosal denture surfaces followed by clasp, tongue, and remaining teeth in that order. Positive correlation were significantly found between the CFU numbers of Candida species and mutans streptococci present on the external surfaces (p < 0.001), natural teeth (p < 0.001), clasp (p < 0.01), and saliva (p < 0.05). A negative correlation (r = -0.503; p < 0.001) was found between the number of teeth and the CFU numbers of Candida species. Moreover, the CFU numbers of both groups of microorganisms also increased in 80-year-old and over persons. Candida species were most predominantly found in persons with poor oral and denture cleanliness.
Three patients in whom flap necrosis developed after oral surgeries and antibiotic therapies were studied microbiologically by routine aerobic and anaerobic methods. In all cases the bacteria Enterobacter cloacae, Klebsiella oxytoca, Escherichia coli, and coagulase-negative penicillinase-producing staphylococci were resistant to the antibiotics used. These bacteria are frequent microorganisms of superinfection and were not found after the necrotic tissues had repaired.
Only recently have human sweat glands been demonstrated to secrete immunoglobulins (Ig), paralleling Ig secretion in mucosal epithelia. It is well established that Ig protect mucosal membranes against infections by binding to surface structures of microorganisms. In view of these findings immunohistochemical studies were performed to determine if microbes on the skin surface are coated by Ig as proposed for mucosal bacteria and fungi. Smear preparations from the skin and oral cavity rich in micro-organisms were subjected to immunoperoxidase staining using anti-secretory component (SC), -IgA, -IgM, -IgG antibodies. An immunogold labeling technique of microbial suspensions of sweat and saliva was adapted to correlate the results on an ultrastructural level. Negative controls included unsuccessful staining for IgA in preparations obtained from an IgA-deficient patient as well as nonreactivity of subcultured microorganisms for all Ig classes or SC. Smear preparations from both the oral cavity and skin surface exhibited labeling of bacterial or fungal elements with anti-IgA, -IgM, -IgG, and -SC antibodies. Skin bacteria revealed a lower number of reactive microbes as compared to saliva. Staining intensity for the different Ig classes exhibited intra- and interindividual variations. Immunoelectronmicroscopically, Ig and SC could be detected either directly along the cell wall of coccal, coryneform, and fungal elements or on floccular and fimbrial material adhering to the bacterial surface. It is concluded that secretory Ig of the skin cover surface structures of microorganisms and thus modify their adhesional and/or infectious properties, resembling humoral surface immunity on mucous membranes.
Bacteroides intermedius strains strongly agglutinated only neuraminidase-treated erythrocytes. The neuraminidase-dependent hemagglutinating activity of B. intermedius was abolished by heating or treating with protease. The adherence of these microorganisms to human buccal epithelial cells was enhanced by neuraminidase pretreatment of the cells (P less than 0.01).
One hundred isolates of the oral pathogenic bacterium Porphyromonas gingivalis were genetically characterized by determining the electrophoretic mobilities of 16 metabolic enzymes and the presence or absence of catalase activity. A total of 78 distinct electrophoretic types (ETs), representing multilocus genotypes, were identified, and cluster analysis placed them in three major phylogenetic divisions. Division I (71 ETs) included all 88 human isolates examined, most of which had been recovered from patients with periodontitis, together with 4 monkey isolates. The strains in division II (four ETs) and division III (three ETs) are strongly differentiated from those in division I and apparently represent two previously unclassified (cryptic) species. The mean genetic diversity per enzyme locus among the 92 isolates of division I (P. gingivalis, strict sense) was 0.321, and the strains were distributed among 14 phylogenetic clusters and single-ET lineages. The population structure is basically clonal, with some clonal genotypes being widespread, and even global, in distribution. There was no evidence of association between specific genetic lineages or clusters of ETs and the type of disease (periodontitis or root canal infections), invasive potential, serogroup, or fimbrial restriction fragment length polymorphism group. The finding that dental patients are infected by strains of a wide variety of chromosomal genotypes suggests that interstrain variation in pathogenicity is small. On the basis of the observed genetic structure of natural populations of P. gingivalis, we hypothesize that the role of this microorganism in the pathogenesis of periodontitis and other dental infections is largely opportunistic.
The aetiology of denture stomatitis is not clear from the literature. Some studies show its aetiology as Candida albicans, while other reports point out the significance of microorganisms. In this study the existence of C. albicans and microorganisms was investigated in subjects with and without denture stomatitis. The results showed that a combination of C. albicans and microorganisms is more likely to be responsible for denture stomatitis.