Virulence factors and antibiotic susceptibility in enterococci isolated from oral mucosal and deep infections

This study evaluates the presence of virulence factors and antibiotic susceptibility among enterococcal isolates from oral mucosal and deep infections. Forty-three enterococcal strains from oral mucosal lesions and 18 from deep infections were isolated from 830 samples that were sent during 2 years to Oral Microbiology, University of Gothenburg, for analysis. The 61 strains were identified by 16S rDNA, and characterized by the presence of the virulence genes efa A (endocarditis gene), gel E (gelatinase gene), ace (collagen binding antigen gene), asa (aggregation substance gene), cyl A (cytolysin activator gene) and esp (surface adhesin gene), tested for the production of bacteriocins and presence of plasmids. MIC determination was performed using the E-test method against the most commonly used antibiotics in dentistry, for example, penicillin V, amoxicillin and clindamycin. Vancomycin was included in order to detect vancomycin-resistant enterococci (VRE) strains. Sixty strains were identified as Enterococcus faecalis and one as Enterococcus faecium. All the virulence genes were detected in more than 93.3% (efa A and esp) of the E. faecalis strains, while the presence of phenotypic characteristics was much lower (gelatinase 10% and hemolysin 16.7%). Forty-six strains produced bacteriocins and one to six plasmids were detected in half of the isolates. Enterococcal strains from oral infections had a high virulence capacity, showed bacteriocin production and had numerous plasmids. They were generally susceptible to ampicillins but were resistant to clindamycin, commonly used in dentistry, and no VRE-strain was found

Oral microbial flora at hyposalivation

Purpose: The overall objective of the present thesis was to study the effect of salivary flow rate on the oral microbial flora and on the saliva composition in groups with hyposalivation of different origins. Material and methods: The oral flora was analysed in rinsing samples from dentate subjects with hyposalivation due to radiation therapy in the head and neck region (RT group), primary Sjögren's syndrome (pSS group), secondary Sjögren's syndrome (sSS group), neuroleptic treatment (Neuro group), medication or of unknown origin (Unknown group). The oral microflora was also analysed in specific sites, on the dorsum of the tongue, buccal mucosa, vestibulum in the molar region, supragingival tooth surface and in the gingival crevice region in subjects with pSS. The micro-organisms registered in rinsing samples were: the total number of micro-organisms growing anaerobically, the total number of streptococci, mutans streptococci, Lactobacilllus spp., Fusobacterium nucleatum, Prevotella intermedia/Prevotella nigrescens, Candida albicans, Staphylococcus aureus and enterics. In samples taken from specific sites also Actinomyces spp., enterococci, Porphyromonas gingivalis and Actinobacillus actinomyctemcomitans were registered. The unstimulated and the stimulated salivary secretion rates and the pH and buffer capacity in stimulated saliva were determined. Lactoferrin, amylase, mucin MUC5B, bicarbonate, sodium, potassium, calcium and phosphate were analysed in stimulated whole saliva. A clinical examination with registration of the status of the mucosal membranes, number of teeth and fillings, bleeding on probing and presence of plaque along the gingival margin was performed. Results: Compared with controls with normal salivary secretion, a decreased bicarbonate concentration was seen in all hyposalivation groups. This probably explains the low numbers of micro-organisms associated with gingival inflammation, which was a common feature for all the groups with hyposalivation as was high levels of Lactobacillus spp., associated with an acidic milieu and caries. The characteristic changes in the pSS group, were the two times higher lactoferrin concentration and the five times higher albumin concentration, indicating serum leakage, and that high numbers of mutans streptococci were frequently detected. In the RT group, the proportionally much larger increase in lactoferrin concentration than in albumin concentration, indicates an acute inflammation in the oral tissues. The RT group was also the only group with a significant decrease in amylase concentration suggest an impaired activity of the parotid glands. This group also had the largest increase in frequency, number and proportion of Lactobacillus spp., and C. albicans, associated with an acidic milieu and mucosal infections. Mutans streptococci were not detected in 29% of the subjects and in high proportions in 29%. The characteristic feature for the Unknown group was that mutans streptococci were detected in all subjects. Otherwise this was the group most similar to the controls regarding microbial flora, saliva proteins and electrolytes analysed. The Neuro group was the only group with dental plaque visible without staining and with the highest proportion of surfaces with bleeding on probing. The characteristic feature for the Neuro group was an increase in amylase, suggesting that more saliva came from the parotid glands than from the submandibular glands. The very low bicarbonate concentration in the Neuro group suggests salivary gland dysfunction. The Neuro group had the highest total microbial count and the lowest proportion of streptococci of all the hyposalivation groups. Conclusion: The present series of studies indicate that the oral microflora and the whole saliva composition are affected differently in subjects with different reasons for hyposalivation

Salivary levels of Osteoprotegerin and receptor activator of nuclear factor-kappa ligand during orthodontic tooth movement : A prospective pilot study

Objectives: The aim of this study was to monitor changes in Osteoprotegerin (OPG) and receptor activator of nuclear factor-kappa ligand (RANKL) levels in the saliva during orthodontic tooth movement (OTM). Materials and Methods: Nine healthy females (15-20 y of age) with four pre-molar extractions and fixed appliance were included. In total, 134 stimulated and 134 unstimulated saliva samples were collected: at baseline and then every 6-8 weeks at follow-up appointments during the whole orthodontic treatment. Twelve age-matched females with no active orthodontic treatment served as a control group. Saliva samples were analysed by enzyme-linked immunosorbent assay (Elisa). The mean levels of OPG and RANKL were calculated according to the different orthodontic treatment stages: alignment, space closure and finishing. A mixed model analysis was used to compare the means of treatment stages. Baseline OPG levels were compared with the control group using an independent t-test. OPG levels were measured in stimulated saliva due to low levels in unstimulated saliva. Results: No significant difference was observed between baseline OPG values and the control group. OPG increased significantly at all treatment stages: alignment, space closure and finishing compared with baseline (P = 0.002, P = 0.039, P = 0.001, respectively). The salivary levels of OPG increased gradually, except during space closure, reaching peak levels at finishing. RANKL was undetectable in stimulated and unstimulated saliva by sandwich Elisa during OTM. Conclusions: This novel approach shows the changes in the levels of OPG in OTM and indicates how and when to sample saliva during orthodontic treatment to analyse bone remodelling

Dental care professionals' awareness of oral dryness and its clinical management : a questionnaire-based study

Background: Despite the high prevalence of oral dryness and awareness of its complications, there is limited research on the clinical management of patients with oral dryness in general dental care. Purpose: To (1) describe and compare awareness among dental care professionals regarding saliva functions, potential causes and complications of oral dryness, and patient management (2) Investigate if the length of professional experience influences these aspects. Methods: A digital self-administrated survey was sent to 2668 dental care professionals working in the general dental care, Public Dental Service, in Sweden. Twelve dental care professionals reviewed the questionnaire prior to its distribution. The questionnaire comprised 32 questions about patient management, awareness of saliva functions, causes and complications of oral dryness, and self-assessment queries. Results: The response rate was 18.6% (241 dentists and 257 dental hygienists). Older adults (65+) were asked more often about dry mouth (93.0%) compared to those aged 18-23 years (50.0%) and those under 18 years (24.9%). Dental hygienists encountered individuals with oral dryness more frequently (61.1%) than dentists (48.5%) (p < 0.01), and more often asked individuals in the age groups 18-23 years (p = 0.003), 24-40 years (p = 0.045), and 41-65 years (p = 0.031) about dry mouth. A higher proportion of dental hygienists (88.3%) than dentists (51.0%) had measured salivary secretion rate, (p < 0.001) and more often suggested preventive dental care 3-4 times a year, (42.5% vs. 30.5%) (p < 0.007). Dentists had a higher awareness of saliva functions, while dental hygienists had a higher awareness about causes and complications of oral dryness. Higher proportions of dentists and dental hygienists with over 10 years of professional experience had measured salivary secretion rate (69.1% vs. 95.7%) compared to their counterparts with less than 10 years of professional experience (35.9% vs. 79.5%) (p < 0.001 for both). Conclusion: Compared to dentists, dental hygienists were more attentive to patients with oral dryness as they encountered these individuals more often, asked more age-groups, suggested frequent preventive measures, and had higher awareness of the causes and complications of oral dryness. Length of professional experience could improve both the management of patients with oral dryness and awareness of its causes, particularly for dental hygienists

Patients with oral lichen planus display lower levels of salivary acidic glycoproteins than individuals without oral mucosal disease

OBJECTIVES: Salivary proteins, acidic glycoproteins, and free calcium might take part in oral mucosal defence against inflammation in oral lichen planus (OLP). The study aimed to investigate whether the levels of sulfated and sialylated glycoproteins, total protein, and free calcium in saliva from patients with OLP differ from those of individuals without oral mucosal diseases. MATERIAL AND METHODS: Patients diagnosed with OLP (n = 25) and two control groups without any oral mucosal disease; age- and gender-matched controls (n = 25, 65.6 ± 2.9 years), and younger controls (n = 25, 41.8 ± 2.5 years) were included. Subjective dry mouth (xerostomia) was assessed by asking a single-item question. Chew-stimulated whole saliva was collected to measure sulfated and sialylated glycoproteins by the Alcian Blue method. The total protein was determined spectrophotometrically, and the free calcium measured using an electrode. RESULTS: The output of salivary sulfated and sialylated glycoproteins in the OLP group (21.8 ± 2.4 µg/min) was lower than in the age- and gender-matched controls (43.0 ± 2.9 µg/min, p = 0.0002), whereas the total protein and calcium output did not differ between the three groups (p > 0.05). The prevalence of xerostomia was significantly higher in the OLP group compared to both control groups (p = 0.038). CONCLUSIONS: Patients with OLP showed a high prevalence of xerostomia and lower levels of salivary acidic type glycoproteins compared to the individuals without oral mucosa disease. CLINICAL RELEVANCE: It is relevant to investigate the role of acidic glycoproteins in the pathogenesis of OLP

Oral health, dental treatment, and medication related osteonecrosis of the jaw in multiple myeloma - a longitudinal cohort study

Objective: The objective of the present study was to investigate oral health status, oral health related quality of life, and identify risk factors associated with invasive dental treatment and medication related osteonecrosis of the jaw in patients with multiple myeloma. Material and methods: Patients newly diagnosed with multiple myeloma (n = 144) referred between January 2015 and September 2022 were retrospectively included. The patients underwent a thorough clinical and radiological oral examination and odontogenic infections were treated before the start of bisphosphonate treatment. The patients were followed annually, including clinical and radiological examinations. The oral health related quality of life was investigated by the OHIP-14 questionnaire. Results: Dental treatment (RR = 7.75), receiving combination antineoplastic therapy≥3 (RR =4.13), periodontitis (RR = 4.21), and reduced number of teeth (RR = 2.87) were associated with an increased risk of medication related osteonecrosis of the jaw. The response rate of the OHIP-14 questionnaire was 70.2%. Oral pain or discomfort in the mouth related to the medical treatment was reported by 30.5%. Conclusion: Dental screening and treatment planning in patients with Multiple Myeloma may result in fewer oral infections and fewer interruptions of the medical treatment of myeloma