Izabela Polkowska
A study of the impact of pathogenic bacteria in periodontal diseases on the internal organs of dogs
The oral cavity of a dog creates ideal conditons for bacterial proliferation due to its stable temperature and moisture level and the inability of dental recesses to self-clean. All these factors favour the development of an inflammatory process and in consequence damage to the gingival pocket epithelium which allows bacterial and toxin translocation into the bloodstream
Aims: testing the hypothesis that there is a correlation between the advanced stages of the parodontium diseases in dogs, the functioning condition of liver and kidneys and pathomorphological changes in selected internal organs; also the assessment of efficacy of surgical methods of treatment of parodontium disases in dogs.
Materials and methods. The study material consisted of 56 dogs, aged between 6 and 15 years with the third and fourth stage of parodontium disease. The dogs were patients of The Clinic of Animal Surgery of Veterinary Medicine Faculty in Lublin in years 2004–2008.
The disease stage was diagnosed on the basis of the results from clinical and radiological examinations. The parodontium examination included a gum recession measurement as well as a measurement of the gingival pocket around four points of each tooth with the use of the Williams probe. During the examination the conditions of gingiva and parodontium were assessed taking into account symptoms like diposition for gum bleeding, gingival pocket depth and teeth movability. Dental treatment involved tartar removal with the help of an ultrasound scaler and topical pharmacological treatment. In 9 dogs with the third stage of periodontal disease, surgical restoration of gingival pocket with the help of hydoxyapatite was performed 14 days after tartar removal and topical treatment. During the four year follow-up and treatment a post mortem group of 19 dogs euthanized in the clinic due to bad general condition was constituted.
In the research group, swabs from gingival pockets were taken for further microbiological analyses. Blood samples were collected for microbiological and morphological tests and radiological examinations were performed to determine the type and degree of alveolar bone loss and to detect the presence of bone pockets. In the post mortem group additional pathomorphological examinations were carried out.
Results and discussion. The analysis of laboratory tests’ results demonstrated a significantly higher alanine aminotransferase activity in periodontal lesions in the fourth stage of the disease than in the third stage of it. The level of aspartate aminotransferase was also elevated in dogs with the fourth stage of parodontium diseases. The urea level was four times higher than normal in dogs with the fourth stage of parodontium disease. It was observed that the white blood cell count was significantly higher statistically in the fourth stage as compared to the third stage of parodontium diseases. The red blood cell count did not vary significantly statistically between the two groups and neither did the hematocrit values. The hemoglobin levels in subjects with the fourth stage of the paradotnium disease were lower than the respective levels in patients with the third stage of the disease. The bacteria most often isolated from the gingival pockets of dogs in the third stage of the disease included Streptococcus sanguis, Peptostreptococcus spp, Escherichia coli, Proteus mirabilis, Veilionella spp,Staphylococcus aureus and Acinobacillus spp.In turn, in the fourth stage the most frequently identified bacteria were Peptostroccocus spp., Streptococcus salivarius, Veilionella spp, Actinomyces viscosus, Staphyloccocus aureus, Actinobacillus actinomycetemcomi Streptococcus pyogenes tans.
In the post mortem group, in dogs with the third stage of the parodontium disease, the bacteriological tests most frequently showed the following bacteria – in gingival pockets: Escherichia coli, Streptococcus sanguis, Streptococcus milleri, Bacteroides forsythus; in kidney tissues: Streptococcus sanguis, Staphyloccocus aureus andcoagulase negative Staphyloccocus spp; and in the left ventricular anterior tissue: Staphyloccocus epidermidis, Streptococcus milleri and Streptococcus pyogenes. The following bacteria were most frequently isolated from the tissues of dogs in the fourth stage of the parodontium disease – from gingival pockets: Provotella spp., Streptococcus milleri, Streptococcus pyogenes, Atinomyces viscosus; from kidney tissues: Staphyloccocus aureus and coagulase negative Staphyloccocus spp.;from the ventricular anterior wall:Staphyloccocus epidermidis, Streptococcus milleri and Streptococcus pyogenes.
Patomorphological tests performed on heart tissue specimens after H + E staining showed the presence of cardiomocytes with acidophilous homogenous cytoplasm with blurred cross-striation and hyperchromatic cell nuclei. Furthermore, single mononuclear cells or sparse clusters of such cells were observed between the muscle fibres and around the vessels. Focally, a fragmentation of cardiomyocytes showed and in some animals, the symptoms of interstitial oedema of varying degree as well as interstitial fibrosis were observed. After staining under Selly’s protocol the presence of fresh necrosis was indicated in the cardiac muscle. In the analyzed kidney samples which were stained routinely under H + E protocol, the morphological changes were noted in most animals in both the renal glomeruli and the renal interstitium. A segmental gllomerular hardening with a noticeable juxtaglomerular and periglomerular fibrosis was observed. In some animals, a segmental mesangial matrix expansion was shown together with glomerulosclerosis. Interstitially, mononuclear cell infiltrations of varying extent were observed in the vicinity of renal glomeruli and tubules as well as a tubular atrophy with the cystic dilation accompanied by the increased interstitial fibrosis and hyanilization. The expansion of the mesagial matrix was noted after the additional staining under PAS protocol. The interstitial fibrosis and glomerular hardening symptoms were shown in the van Gieson’s and Masson’s Trichrome stainings.
Conclusions. The obtained results indicate the presence of compatible bacterial strains in gingival pockets, coronary valves and renal pelvises in dogs. Monitoring a dog’s general health and treatment of parodontium diseases can eliminate some sources of bacterial infections of the internal organs. Successful treatment of parodontium diseases requires periprocedural anibiotic prophylaxis and a close cooperation between the veterinarian and the dog’s owner. Surgical reconstruction of gingival pockets in dogs is only possible when owners closely follow the appropriate medical recommendations. The oral cavity examinations and dental prophylaxis ought to constitute a permanent element of a routine care over small animals. The results of this research carried out over the last few years form a contribution to the ongoing search for correlation and interdependence between the parodontium diseases and the condition of the internal organs.