Indigenous Oral Bacteria Research Articles

Periodontal Abscess and Pyorrhea: Proposal for a Novel Treatment with Ozone Nanobubble Saline Wash

The evolution of the treatment technologies in dentistry is remarkable. However, despite the advancement of science and therapeutic agents, they have not been able to overcome dental caries, periodontal disease [1], nor alveolar pyorrhea [2]. We are attempting to eliminate hundreds of oral bacteria, partly because we are fighting indigenous oral bacteria [3]. Currently, although many patients are trained in proper oral hygiene, including teeth brushing, flossing, and use of mouthwash daily, many still suffer from periodontal diseases, such as gingivitis [1]. Despite training and the abundance of oral healthcare products [4] widely available, including fluorides, chlorhexidine, and triclosan, oral health diseases remain a prominent issue. Beyond periodontal disease and gingival inflammation, extremely problematic conditions [1], such as periodontal abscesses [1] and alveolar pyorrhea [2], are some of the potential problems for patients and dentists. The most problematic condition is alveolar pyorrhea [2], advanced conditions of gingival inflammation [1], with symptoms including painful chewing, swollen or puffy gums, gum bleeding, and pus in the gums. These symptoms gradually appear, and in untreated conditions, lead to tooth loss. The advent and development of antibiotics have greatly impacted the treatment of bacterial infections. However, local bacterial infection lesions in various parts, such as dental fistulae [5], have not yet been overcome. The emergence of resistant strains is also a problem; the peculiarity of the conditions, such as fistula-like sites and infected wounds, is still a major obstacle to bacterial infections. These periodontal and gingival diseases [1] are treated with systemic antibiotics during the acute phase [4], but they are not always completely cured. It should be noted that bacterial infections in the oral cavity remain unresolved issues.

Associations of streptococci and fungi amounts in the oral cavity with nutritional and oral health status in institutionalized elders: a cross sectional study

BackgroundDisruption of the indigenous microbiota is likely related to frailty caused by undernutrition. However, the relationship between undernutrition and the oral microbiota, especially normal bacteria, is not obvious. The aim of this study was to elucidate the associations of nutritional and oral health conditions with prevalence of bacteria and fungi in the oral cavity of older individuals.MethodsForty-one institutionalized older individuals with an average age ± standard deviation of 84.6 ± 8.3 years were enrolled as participants. Body mass index (BMI) and oral health assessment tool (OHAT) scores were used to represent nutritional and oral health status. Amounts of total bacteria, streptococci, and fungi in oral specimens collected from the tongue dorsum were determined by quantitative polymerase chain reaction (PCR) assay results. This study followed the STROBE statement for reports of observational studies.ResultsThere was a significant correlation between BMI and streptococcal amount (ρ = 0.526, p < 0.001). The undernutrition group (BMI < 20) showed a significantly lower average number of oral streptococci (p = 0.003). In logistic regression models, streptococcal amount was a significant variable accounting for “not undernutrition” [odds ratio 5.68, 95% confidential interval (CI) 1.64–19.7 (p = 0.06)]. On the other hand, participants with a poor oral health condition (OHAT ≥ 5) harbored significantly higher levels of fungi (p = 0.028).ConclusionOral streptococci were found to be associated with systemic nutritional condition and oral fungi with oral health condition. Thus, in order to understand the relationship of frailty with the oral microbiota in older individuals, it is necessary to examine oral indigenous bacteria as well as etiological microorganisms.

Colorectal Cancer Patients Have Four Specific Bacterial Species in Oral and Gut Microbiota in Common-A Metagenomic Comparison with Healthy Subjects.

Simple SummaryThe incidence of colorectal cancer (CRC) has been increasing in recent years, and the gut microbiota is nowadays considered to be involved in the progression of CRC. Recent studies have investigated the involvement of the oral microbiota in CRC development using saliva and stool samples. However, the details regarding how oral bacteria alter the gut microbiota and affect CRC carcinogenesis remain unclear. In the present study, we identified four bacterial species that may affect the carcinogenesis and progression of CRC. These microorganisms may be potential biomarkers in saliva for diagnosing CRC.Oral microbiota is reportedly associated with gut microbiota and influences colorectal cancer (CRC) progression; however, the details remain unclear. This study aimed to evaluate the role of oral microbiota in CRC progression. Fifty-two patients with CRC and 51 healthy controls were included. Saliva and stool samples were collected, and microbiota were evaluated using 16S rRNA analysis and next-generation sequencing. Comparative analysis was performed on both groups. Linear discriminant analysis effect size (LEfSe) revealed the presence of indigenous oral bacteria, such as Peptostreptococcus, Streptococcus, and Solobacterium spp., at a significantly higher relative abundance in saliva and stool samples of CRC patients compared with controls. Next, CRC patients were divided into early stage (Stage I, II; n = 26; 50%) and advanced stage (Stage III, IV; n = 26; 50%) disease. LEfSe revealed that S. moorei was present at a significantly higher relative abundance in the advanced-stage group compared with the early-stage group, again consistent for both saliva and stool samples. Among bacterial species with significantly higher relative abundance in CRC patients, P. stomatis, S. anginosus, S. koreensis, and S. moorei originated from the oral cavity, suggesting indigenous oral bacteria may have promoted initiation of CRC carcinogenesis. Furthermore, S. moorei may influence CRC progression.

Streptococcus mutans detection on mother-child pairs using matrix-assisted laser desorption ionization – time of flight mass spectrometry and polymerase chain reaction

Background: Streptococcus mutans (S. mutans) bacteria mainly cause dental caries in children. These bacteria are not considered oral indigenous bacteria since they are transmitted from people around children during their deciduous teeth eruption. The detection of these bacteria can be used for dental caries prevention in children. Purpose: To determine the strain and serotype of S. mutans by using matrix assisted laser desorption ionization – time of flight mass spectrometry (MALDI-TOF MS) and polymerase chain reaction (PCR) on dental plaque samples taken from mother-child pairs. Methods: Sixteen dental plaque samples of mother-child pairs were cultured on brain heart infusion broth (BHIB) and mitis salivarius bacitracin (MSB) media until S. mutans colony isolates were obtained. Next, the isolates of S. mutans colony were introduced into the target plates of MALDI-TOF MS, and then ionized to become peptide mass fingerprint (PMF). Afterwards, the colony isolates were detected by database software. The detected S. mutans DNA then was extracted by using conventional 727 bp PCR (serotype C). Results: Six strains of S. mutans were detected by MALDI-TOF MS method. Five samples were classified into UA159, two samples were 3SN1, two samples were NFSM1, two samples were 11A1, two samples were U138, two samples were 4SM1, and one sample was classified into another bacterium. Five out of 16 samples were detected by PCR as serotype C (UA159). Conclusion: Six strains of S. mutans were detected, namely UA159, 3SN1, NFSM1, 11A1, U138, and 4SM1, one of them (UA159) was detected as serotype C.

Involvement of Oral Microbiota in the Gut Microbiota of Colorectal Cancer

Background: The oral microbiota is reportedly associated with the gut microbiota and influences colorectal cancer (CRC) progression; however, the details remain unclear. Methods: This study included 52 patients diagnosed with CRC and 51 healthy controls. Saliva and stool samples were collected, and microbiota were evaluated using 16S rRNA analysis and next-generation sequencing. Comparative analysis was performed on both groups. Findings: Linear discriminant analysis Effect Size (LEfSe) revealed indigenous oral bacteria, such as Peptostreptococcus, Streptococcus, and Solobacterium spp., were present at a significantly higher relative abundance in CRC patients compared with controls, consistent for both saliva and stool. LEfSe was also performed after the CRC patients were divided into early stage (Stage I, II; n = 26; 50%) and advanced stage (Stage III, IV; n = 26;, 50%) disease. S. moorei was present at a significantly higher relative abundance in the advanced-stage group compared with the early-stage group, again consistent for both saliva and stool. Interpretation: Among the bacterial species whose relative abundance was significantly higher in CRC patients, P. stomatis, S. anginosus, S. koreensis and S. moorei were apparently supplied from the oral cavity, suggesting indigenous oral bacteria may have promoted initiation of CRC carcinogenesis. Furthermore, S. moorei may influence CRC progression. Funding Statement: This research was supported by Grants-in-Aid for Scientific Research from the Japan Society for the Promotion of Science (19K10361)(15H05045). Declaration of Interests: All authors declare no interests. Ethics Approval Statement: The study was conducted in accordance with the “Declaration of Helsinki.” The study protocols were approved by the ethics committee of Kagoshima University. Informed consent was obtained from all the study participants.

Oral challenge with Streptococcus sanguinis induces aortic inflammation and accelerates atherosclerosis in spontaneously hyperlipidemic mice

Atherosclerosis is exacerbated by periodontal pathogens, which induce vascular inflammation after entering the bloodstream. Among oral indigenous bacteria, Streptococcus sanguinis and S. anginosus are related to systemic disorders, such as infective endocarditis and abscess, and are sometimes detected in human atherosclerotic plaques or blood. Thus, these oral streptococci may contribute to the progression of atherosclerosis. To test this hypothesis, apolipoprotein E-deficient spontaneously hyperlipidemic mice were intraorally challenged with S. sanguinis or S. anginosus. Atherosclerotic plaque formation increased significantly in the S. sanguinis-challenged group compared with the carboxymethylcellulose-treated control group. Expression levels of mRNAs of proinflammatory cytokines in the aorta and levels of atherosclerosis-related mediators in blood increased upon S. sanguinis challenge. Adaptor molecule TNF receptor-associated factor 6 was also enhanced in the aorta when mice were challenged with S. sanguinis. Furthermore, challenge with S. anginosus induced systemic inflammation, but inflammation-related mRNA expression levels in the aorta only increased slightly and were accompanied by minimal expansion of the lesion area. By contrast, with the exception of IL-1α, the expression levels of inflammation-related genes did not change in gingival tissues of both bacteria- and sham-challenged groups. These results reveal that S. sanguinis causes aortic inflammation that leads to accelerated progression of atherosclerosis.

Effects of magnetic fields from electric toothbrushes on fluoride- and oral bacteria-induced corrosion of orthodontic metallic wires.

Corrosion of metallic materials in the oral cavity could trigger metal allergy in patients. To clarify the risk elevation of magnetic fields (MFs) exposure on metallic corrosion when combined with fluoride-containing dental care products and indigenous oral bacteria, we investigated electric toothbrush-derived MF-induced corrosion of orthodontic stainless steel (SUS) and nickel titanium (Ni-Ti) wires in the presence of fluoride and oral bacteria, i.e. Streptococcus (S) mutans and S. sanguinis. MFs induced an electric current in the wires under both environments. Oral bacteria corroded SUS wires, and fluoride corroded SUS and Ni-Ti wires as previously reported; however, no additive or synergistic effects of MF exposure on fluoride- and microbiologically-induced metallic corrosion were observed. These results suggest that the MFs from electric toothbrushes do not increase the risk of corrosion of metallic appliances, given that the oral environment of patients is exposed to oral bacteria and fluoride-containing products.

Metabolic property of acetaldehyde production from ethanol and glucose by oral Streptococcus and Neisseria

Acetaldehyde is known to be carcinogenic and produced by oral bacteria. Thus, bacterial acetaldehyde production might contribute to oral cancer. Therefore, we examined bacterial acetaldehyde production from ethanol and glucose under various conditions mimicking the oral cavity and clarified the metabolic pathways responsible for bacterial acetaldehyde production. Streptococcus mitis, S. salivarius, S. mutans, Neisseria mucosa and N. sicca were used. The bacterial metabolism was conducted at pH 5.0–8.0 under aerobic and anaerobic conditions. The production of acetaldehyde and organic acids was measured with gas chromatography and HPLC, respectively. Bacterial enzymes were also assessed. All of the bacteria except for S. mutans exhibited their greatest acetaldehyde production from ethanol at neutral to alkaline pH under aerobic conditions. S. mutans demonstrated the greatest acetaldehyde from glucose under anaerobic conditions, although the level was much lower than that from ethanol. Alcohol dehydrogenase and NADH oxidase were detected in all of the bacteria. This study revealed that oral indigenous bacteria, Streptococcus and Neisseria can produce acetaldehyde, and that such acetaldehyde production is affected by environmental conditions. It was suggested that alcohol dehydrogenase and NADH oxidase are involved in ethanol-derived acetaldehyde production and that the branched-pathway from pyruvate is involved in glucose-derived acetaldehyde production.

A case of multiple infectious intracranial aneurysms concurrently presenting with intracerebral hemorrhage and epistaxis

Abstract Infectious intracranial aneurysms (IIAs) have the specific features of rapid growth and multiplicity, which often show various pathologies and serious symptoms when ruptured. There are few previous reports of multiple IIAs that concurrently present with intracerebral hemorrhage (ICH) and epistaxis. A 62-year-old man with a history of tooth extraction 1.5 months before experienced an intracranial abscess in the left Sylvian fissure and insula cortex. The patient underwent a craniotomy to drain the abscess and he experienced a heavy epistaxis, which required intranasal gauze packing immediately after surgery. Subsequently, he had a massive ICH on the left temporal lobe resulting from a ruptured IIA in the left middle cerebral artery on day 8. Surgical trapping of the aneurysm contributed to a complete cure. Oral indigenous bacteria was obtained by culturing an aspirate of the abscess cavity. A follow-up radiological examination revealed that the right internal carotid artery (ICA) aneurysm in the cavernous segment concurrently grew and the aneurysmal rupture had caused the epistaxis. We performed stent-assisted coil embolization for the aneurysm on day 20 and achieved radiological resolution. Although right hemiparesis and some communication problems remained, the patient recovered but needed minimal assistance. Given multiple progressions and their destructive pathology, more attention needs to be paid to IIAs. Our multimodal strategy achieved clinical resolution, and IIAs should be treated immediately with appropriate radical intervention depending on the lesion location.

Microbiological assessment of effects of clinical mouth rinses on common oral microbes.

Dry mouth occurs frequently in aged individuals, as well as in patients who are hospitalized, receiving multiple drugs, undergoing radiation treatment to the head and neck, or wearing a removable denture prosthesis, use of mouth rinse being often an option for relief. In the present study, we performed microbiological assessments of subjects given three different commercially available mouth rinses commonly employed in clinical practice (Peptisal, Biotène, ConCool) to determine their effects. For bacterial clearance in vitro, Peptisal showed the highest level of suppression of oral indigenous bacteria found in both planktonic formations and biofilm. Furthermore, the inhibitory effects of these agents on biofilm formation on acrylic resin plates were examined using scanning electron microscopy. Again, Peptisal proved superior, because acquisition of resistance to antimicrobial peptides by a sensitive microbial strain was rarely observed. We conclude that Peptisal is an effective mouth rinse for clearance of planktonic and biofilm microorganisms present in the oral cavity.

Keynote Address I: Oral Candida in health and disease

As about one half of the human population harbour Candida species, the demystification of their conversion from commensalism to parasitism causing mucosal and systemic candidiasis would be of considerable value in the management of these ailments, especially in compromised population groups. Human candidiasis ranges from superficial infections of the oral and vaginal mucosae, to life threatening multi-organ systemic affections. My presentation describes how I attempted, over a period of three decades, to unveil the pathogenic mechanisms of an enemy that ‘sleeps with us‘ ordinarily, yet strikes with a vengeance given the opportunity. In brief, the data presented is a thumb sketch of various novel discoveries on the clinical epidemiology, aetiopathogenesis, and clinical management of oral candidal infections. Clinical epidemiological findings from various cohorts including diabetics, those on cytotoxic therapy, comatose patients, stroke sufferers, and from healthy individuals in three continents indicated that the previous data on oral candidal carriage rates in healthy humans of 40–60% derived essentially from the West cannot be extrapolated into Asia. Our findings indicate the prevalence rates are relatively low in healthy Asians ranging from 14% to 40%. With regard to aetiopathogenesis, candidal biofilm life style is now considered a crucial determining factor. A multitude of studies we conducted illustrate (i) how dietary carbohydrates modulate biofilms, and its clinical implications on the genesis of oral candidiasis, (ii) the conflicting role of whole saliva, serum, and sub-therapeutic concentrations of antifungals on yeast biofilms, (iii) the finding that the drug resistance of candidal biofilms is due to their intrinsic anti-oxidative capacities, and (iv) the role of indigenous oral bacteria in both inhibiting and fostering yeast biofilm development. With the advent of the HIV epidemic novel variants of oral candidiasis were described, throwing into disarray the conventional disease classification. Hence a new improved classification, that has now received worldwide acceptance was proposed, where the disease entities are principally categorised as primary and secondary oral candidiasis, with further new sub-divisions thereafter. An extensive enquiry into the oral manifestations of Asian and African cohorts with HIV disease highlights salivary defences and secondary oral diseases that may differ from Western populations. Other novel findings relevant to HIV infection that will be discussed include, (i) the identification of global sub-types of oral Candida albicans, (ii) the ultrastructure of pseudomembranous candidiasis (iii) increased Sap expression in C. albicans and, (iv) the enhanced avidity of Candida to buccal epithelium of HIV carriers. Management of the clinical variants of oral candidiasis poses new challenges and epidemiological surveys amongst both the young and the elderly in differing geographic locales indicate the relatively high, yet poorly managed disease. For instance, the dual, candidal-staphylococcal aetiology of angular cheilitis - an oft-ignored, peri-oral variant of candidiasis. In conclusion, this presentation redefines the clinical epidemiology, and the complex behavioural patterns of Candida species within the human oral habitat, that may lead to a deeper understanding of the prevention and management of mucosal candidal infections in general, and oral candidiasis, specifically.

Incidence of oral indigenous bacteria in causative strains isolated from blood cultures in 759 laboratory-confirmed cases of bacteremia

Abstract Background: The incidence of oral indigenous bacteria in cases of bacteremia has been reported in only a few studies. We investigated the annual incidence of oral indigenous bacteria isolated in blood cultures from patients with bacteremia and call into consideration the impact of oral health measures implemented at our facility. Methods: In the period from 2001 to 2006, 759 laboratory-confirmed cases of bacteremia were reported and subsequently analyzed in this study. The incidences of the causative strain and oral indigenous bacteria in blood cultures were studied by year. Results: In 759 cases of bacteremia, oral streptococci were noted in 14 (1.8%), and anaerobic bacteria were noted in 9 (1.2%). The population of microorganisms did not change significantly during the study period. Conclusions: In a previous report, oral streptococci accounted for 3.8% of those under investigation. In this study, the incidence of oral streptococci was significantly low, 1.8% specifically. A focus on oral health care at our hospital may account for a reduced incidence of oral streptococci bacteremia.

Can oral pathogens influence allergic disease?

The hygiene hypothesis contends that fewer opportunities for infections and microbial exposures have resulted in more widespread asthma and atopic disease. Consistent with that hypothesis, decreases in infectious oral diseases over the past half century have coincided with increases in the prevalence of asthma and other allergic diseases. This observation has led some researchers to speculate that exposures to oral bacteria, including pathogens associated with periodontal diseases, such as gingivitis and periodontitis, might play a protective role in the development of asthma and allergy. Colonization of the oral cavity with bacteria, including some species of periodontal pathogens, begins shortly after birth, and the detection of serum antibodies to oral pathogens in early childhood provides evidence of an early immune response to these bacteria. Current knowledge of the immune response to oral bacteria and the immunologic pathogenesis of periodontal diseases suggests biologically plausible mechanisms by which oral pathogens could influence the risk of allergic disease. However, studies investigating the association between oral pathogen exposures and allergic disease are few in number and limited by cross-sectional or case-control design, exclusion of young children, and use of surrogate measures of oral bacterial colonization. Additional studies, particularly well-designed case-control studies among very young children and prospective birth cohortstudies, are needed.

ウサギ口蓋へん桃を介した唾液中常在菌に対する自然抗体の誘導

We isolated the predominant indigenous bacteria from the saliva of non-immune rabbits. The presence of naturally occurring antibodies to the isolated bacteria and the induction of these antibodies were then studied. The bacteria in the saliva was identified as Staphylococcus lentus using a commercial identification kit, and found to have 1.5 (±2.2) × 106 cells/ml and to account for 16.1 (±5.6)% of the bacteria grown under aerobic condition. The concentration of anti-S. lentus antibodies in the saliva of non-immune rabbits was higher than that of the other kinds of staphylococci in ELISA. In non-immune rabbits, the anti-S. lentus IgA antibodies in the saliva was higher than that in the nasal wash and the intestinal fluid, while the anti-S. lentus IgA antibodies in the saliva, the nasal wash and the intestinal fluid were similar in level. When the suspension of fluorescence-labeled isolated Sta. lentus cells in saliva was applied to palatine tonsil of rabbits, many spots of the fluorescence were found in the cortex of the tonsil. Weekly tonsillar application of 1010 isolated Sta. lentus cells in one ml PBS caused an increase in the concentration of anti-S. lentus IgA antibodies in saliva the and the IgG antibodies and IgM antibodies in the blood plasma. Even one week following the first application of isolated Sta. lentus, the antibodies in the saliva were found to have increased. The anti-S. lentus antibodies was induced by the application of 108 cells or 106 cells. The antibody level after six weeks of these applications was similar in level to that applied 1010 cells. The above results show that naturally occurring antibodies to the predominant indigenous oral bacteria were induced in the saliva of rabbits through the stimulation of the palatine tonsil.

The biological basis for the attenuation of mucositis: the example of interleukin-11.

Oral mucositis is common, painful, dose-limiting toxicity of drug and radiation therapy for cancer. In granulocytopenic patients, the ulcerations which accompany mucositis are frequent portals of entry for indigenous oral bacteria often leading to bacteremias or sepsis. The complexity of mucositis as a biological process has only recently been appreciated. The condition appears to represent a sequential interaction of the oral mucosal cells and tissues, pro-inflammatory cytokines, and local environmental factors in the mouth such as microorganisms and saliva. The recognition that the pathophysiology of mucositis is a multifactorial process has presented opportunities for intervention based on biological attenuation. Interleukin-11, a pleotropic cytokine, has a range of activities which is potentially relevant to mucositis. Consequently, it has been used successfully to modify the development, severity and course of mucositis in an animal model which closely mimics the equivalent human condition.

嫌気性菌を同時に分離した副鼻腔真菌症の１例

We observed and treated mycosis affecting an extensive area of the paranasal sinuses. A 63-year-old woman was referred to our hospital because of left cheek swelling. Both maxillary sinuses were cloudy on X-ray examination. CT examination showed a low density area that included high density areas in both maxillary sinuses and the left ethmoid sinus. After these examinations, we diagnosed this case as bilateral maxillary and left ethmoid sinusitis dentalis with suspected mycosis. Surgery was performed under general anesthesia. Histological examination revealed fungi. Fungi were detected in culture specimens and identified as Aspergillus. At the same time, oral indigenous bacteria closely related to odontogenic infections, i.e., Streptococcus constellatus, Peptostreptococcus anaerobius, Prevotella intermedia, and Prevotella sp., were isolated for anaerobic culture. Clinically and microbiologically, these results suggest that this case was caused first by odontogenic infection, followed by the adherence and proliferation of Aspergillus.

口こう感染症における嫌気性グラム陰性かん菌の検討

Most anaerobes isolated in oral infections are anaerobic gram-negative rods such as Prevotella, Porphyromonas and Fusobacterium. However, isolation of these organisms is more difficult than other anaerobes. In particular, the isolation rate of anaerobic gramnegative rods is not sufficient even though they are indigenous oral bacteria. We therefore used Brucella HK Agar w/PV (LR) with basal medium to isolate anaerobic gram-negative rods selectively and examined the usefulness of this technique. A total 132 isolates (55 aerobes and 77 anaerobes) were isolated from 48 cases of oral infections. When we used only modified GAM agar, only 17 anaerobic gram-negative rods were isolated (isolation rate: 15.6%). But when we used Brucella HK Agar w/PV (LR) with modified GAM agar, 40 anaerobic gram-negative rods were obtained (isolation rate: 30.3%). The number of isolated Prevotella and Porphyromonas was 22. Ten of them formed black-pigmented colonies.More than 95% of strains of anaerobic gram-negative rods were susceptible to CEZ, CMZ, LMOX, IPM, TC and CLDM.

口腔常在細菌の増殖性と酸化還元酵素について ＩＩＩ Ｖｅｉｌｌｏｎｅｌｌａ ａｌｃａｌｅｓｃｅｎｓの過酸化水素分解酵素について

口腔常在細菌であるV. alcalescensの過酸化水素分解酵素を部分精製した。この酵素は, ヘムを活性基とするが, 肝, およびM. luteusのカタラーゼと異なるタイプの酵素であると推察された。

Interbacterial adhesion between Pseudomonas aeruginosa and indigenous oral bacteria isolated from patients with cystic fibrosis.

Interbacterial adhesion between strains of Pseudomonas aeruginosa and strains of indigenous oral bacteria, both of which were isolated from the oral cavity of cystic fibrosis patients, was investigated by the phenomenon of the coaggregation reaction. A total of 22 strains of P. aeruginosa were isolated from the oral cavity of 17 patients and examined for their abilities to coaggregate with 5 strains each of Streptococcus sanguis, Streptococcus mitis, Actinomyces viscosus, and Actinomyces naeslundii. Coaggregation reactions were common between these oral bacteria and both the mucoid and nonmucoid variants of P. aeruginosa. All strains of P. aeruginosa were also able to agglutinate neuraminidase-treated or untreated human erythrocytes of blood types A, B, and O. Positive coaggregation reactions were further characterized by determining the effects of several sugars, and of heat and protease treatments of the bacteria. None of the coaggregtion reactions were inhibited by 0.05 M lactose, galactose, glucose, fucose, or mannose. All coaggregation reactions were dependent upon heat- and protease-sensitive components of the Pseudomonas. Thus, the interbacterial adhesions between P. aeruginosa and the oral bacteria studied appears to involve adhesins on the Pseudomonas cell, which bind to complementary receptors, on the cell surfaces of oral bacteria. The apparent prevalence and diversity of interbacterial adhesions between P. aeruginosa strains originating from the oral cavity of cystic fibrosis patients and strains of the indigenous oral bacteria suggest that some of these reactions may affect the extent to which P. aeruginosa colonizes in the oral cavity of cystic fibrosis patients, and thereby, influence susceptibility of the host to infection.

口こう常在細菌の増殖性と酸化還元酵素について Ｉ 各種酸素濃度下における口こう常在細菌の増殖性

各種の口腔常在細菌の酸化還元酵素産生能とそれらの細菌の増殖能に及ぼす酸素の影響との関係について研究を行った。本報では細菌の増殖能に及ぼす酸素の影響についてのみ述べる。実験は半流動寒天培地を用いた穿刺, および混釈培養と, 液体培地を用いた好気および嫌気振盪培養を行った。穿刺培養は好気条件下で, 混釈培養は好気および高濃度の酸素の環境下で培養を行った。振盪培養では嫌気振盪の濁度を基準として好気振盪の濁度との比 (RBGR) を求めた。facultative anaerobesでは, RBGRは (1.8-6.0) の値を示した。aerotolerant anaerobesでは, 混釈培養法で少量の細菌を接種した場合, 大気中でも上層部に増殖阻止帯が認められた。この阻止帯は, 高濃度の酸素下では著明となった。このことから, 阻止帯の出現は酸素の影響によるものと考えられた。これらのことから, aerotolerant anaerobesはobligate anaerobesと同じく酸化還元酵素系の発達が悪く, 酸素に対して感受性を持つことが示唆された。