Acute Dentoalveolar Abscess (Microbiological and Clinical Studies)

Acute dentoalveolar abscess is a common infection of man which originates at the root apex of a tooth with a necrotic pulp and spreads locally into the surrounding facial tissues. Recent studies have shown that these abscesses are usually polymicrobial with anaerobic gram-positive cocci or anaerobic gram-negative bacilli being the predominant species. Although the literature contains qualitative information about the types of microorganisms involved, little quantitative data is available on the overall microbial load and the relative proportions of individual bacterial strains. The present study was performed to characterise and quantify the microbial species present in each of 50 acute dentoalveolar abscesses using aspiration sampling and culture techniques capable of isolating strictly anaerobic bacteria. Not only did the results confirm that acute dentoalveolar abscesses usually contain a mixture of bacterial species (mean number of species per abscess, 3.3) but also revealed that organisms were present in high concentrations (mean bacterial load, 7.9 x 10e6 cfu/ml). Forty per cent of the abscesses studied had a purely anaerobic flora whereas 6 per cent yielded facultative bacteria only. Although a mixture of facultative and strictly anaerobic bacterial species was cultured from 27 abscesses, strict anaerobes predominated in all but 5 of these cases. A wide range of bacteria was isolated but Strep. milleri, Peptococcus species, Peptostreptococcus species, B. oralis, B. gingivalis and B. melaninogenicus were the most frequent. Not only were strict anaerobes isolated more often than facultative bacteria but they were also recovered in higher concentrations. The results of this study confirmed the polymicrobial nature of acute dentoalveolar abscess and provided scientific data to support the current general impresssion that strict anaerobes predominate in these lesions

Impact of bidirectional relationships between streptococcus anginosus group and host tissue matrix components on cellular activity: Role in establishment of infection

This paper investigates pathogenic mechanisms of the Streptococcus anginosus group (SAG) of bacteria which influence the biological activity of periodontal ligament (PDL) cells, endothelial cells and also how matrix proteins produced by these host cells influence bacterial virulence factors. Isolates of SAG species, designated S. anginosus, S. constellatus and S. intermedius, were derived from healthy commensal and clinical pathogenic infection sites. SAG culture supernatants contained multiple protein components which differed between isolates. All SAG supernatants increased cellular proliferation and decreased decorin synthesis and collagen assembly by PDL cells and reduced endothelial cell migration. SAG isolates responded differently to extracellular matrix (ECM) components synthesised by PDL cells, but there was an overall notable increase in hydrolytic enzyme activity and in the production of the cytotoxin intermedilysin by S. intermedius. Collectively, the results indicate that both commensal and pathogenic SAG isolates were capable of impairing the ability of PDL cells and endothelial cells to make functional vascularised tissue. Reduced decorin synthesis is likely to have a major impact on cell signalling, angiogenesis and matrix assembly. Furthermore, ECM components produced by PDL cells were differentially capable of moderately increasing SAG enzymic activity, leading to subtle ECM modifications. The impact this bidirectional effect has on the tissue remodelling process is discussed

Impact of bidirectional relationships between streptococcus anginosus group and host tissue matrix components on cellular activity: Role in establishment of infection

This paper investigates pathogenic mechanisms of the Streptococcus anginosus group (SAG) of bacteria which influence the biological activity of periodontal ligament (PDL) cells, endothelial cells and also how matrix proteins produced by these host cells influence bacterial virulence factors. Isolates of SAG species, designated S. anginosus, S. constellatus and S. intermedius, were derived from healthy commensal and clinical pathogenic infection sites. SAG culture supernatants contained multiple protein components which differed between isolates. All SAG supernatants increased cellular proliferation and decreased decorin synthesis and collagen assembly by PDL cells and reduced endothelial cell migration. SAG isolates responded differently to extracellular matrix (ECM) components synthesised by PDL cells, but there was an overall notable increase in hydrolytic enzyme activity and in the production of the cytotoxin intermedilysin by S. intermedius. Collectively, the results indicate that both commensal and pathogenic SAG isolates were capable of impairing the ability of PDL cells and endothelial cells to make functional vascularised tissue. Reduced decorin synthesis is likely to have a major impact on cell signalling, angiogenesis and matrix assembly. Furthermore, ECM components produced by PDL cells were differentially capable of moderately increasing SAG enzymic activity, leading to subtle ECM modifications. The impact this bidirectional effect has on the tissue remodelling process is discussed

Real-time monitoring of adherence of Streptococcus anginosus group bacteria to extracellular matrix decorin and biglycan proteoglycans in biofilm formation

Members of the Streptococcus anginosus group (SAGs) are significant pathogens. However, their pathogenic mechanisms are incompletely understood. This study investigates the adherence of SAGs to the matrix proteoglycans decorin and biglycan of soft gingival and alveolar bone. Recombinant chondroitin 4-sulphate(C4S)-conjugated decorin and biglycan were synthesised using mammalian expression systems. C4S-conjugated decorin/biglycan and dermatan sulphate (DS) decorin/biglycan were isolated from ovine alveolar bone and gingival connective tissue, respectively. Using surface plasmon resonance, adherence of the SAGs S. anginosus, Streptococcus constellatus and Streptococcus intermedius to immobilised proteoglycan was assessed as a function of real-time biofilm formation. All isolates adhered to gingival proteoglycan, 59% percent of isolates adhered to alveolar proteoglycans, 70% to recombinant decorin and 76% to recombinant biglycan. Higher adherence was generally noted for S. constellatus and S. intermedius isolates. No differences in adherence were noted between commensal and pathogenic strains to decorin or biglycan. DS demonstrated greater adherence compared to C4S. Removal of the glycosaminoglycan chains with chondroitinase ABC resulted in no or minimal adherence for all isolates. These results suggest that SAGs bind to the extracellular matrix proteoglycans decorin and biglycan, with interaction mediated by the conjugated glycosaminoglycan chain

Comparison of foam swabs and toothbrushes as oral hygiene interventions in mechanically ventilated patients: a randomised split mouth study

Abstract Introduction During critical illness, dental plaque may serve as a reservoir of respiratory pathogens. This study compared the effectiveness of toothbrushing with a small-headed toothbrush or a foam-headed swab in mechanically ventilated patients. Methods This was a randomised, assessor-blinded, split-mouth trial, performed at a single critical care unit. Adult, orally intubated patients with >20 teeth, where >24 hours of mechanical ventilation was expected were included. Teeth were cleaned 12-hourly using a foam swab or toothbrush (each randomly assigned to one side of the mouth). Cleaning efficacy was based on plaque scores, gingival index and microbial plaque counts. Results High initial plaque (mean=2.1 (SD 0.45)) and gingival (mean=2.0 (SD 0.54)) scores were recorded for 21 patients. A significant reduction compared with initial plaque index occurred using both toothbrushes (mean change=−1.26, 95% CI −1.57 to −0.95; p<0.001) and foam swabs (mean change=−1.28, 95% CI −1.54 to −1.01; p<0.001). There was significant reduction in gingival index over time using toothbrushes (mean change=−0.92; 95% CI −1.19 to −0.64; p<0.001) and foam swabs (mean change=−0.85; 95% CI −1.10 to −0.61; p<0.001). Differences between cleaning methods were not statistically significant (p=0.12 for change in gingival index; p=0.24 for change in plaque index). There was no significant change in bacterial dental plaque counts between toothbrushing (mean change 3.7×104 colony-forming units (CFUs); minimum to maximum (−2.5×1010 CFUs, 8.7×107 CFUs)) and foam swabs (mean change 9×104 CFUs; minimum to maximum (−3.1×1010 CFUs, 3.0×107 CFUs)). Conclusions Patients admitted to adult intensive care had poor oral health, which improved after brushing with a toothbrush or foam swab. Both interventions were equally effective at removing plaque and reducing gingival inflammation. Trial registration number NCT01154257; Pre-results

Molecular Analysis of Microbial Communities in Endotracheal Tube Biofilms

Ventilator-associated pneumonia is the most prevalent acquired infection of patients on intensive care units and is associated with considerable morbidity and mortality. Evidence suggests that an improved understanding of the composition of the biofilm communities that form on endotracheal tubes may result in the development of improved preventative strategies for ventilator-associated pneumonia. (n = 5). DGGE profiling of the endotracheal biofilms revealed complex banding patterns containing between 3 and 22 (mean 6) bands per tube, thus demonstrating the marked complexity of the constituent biofilms. Significant inter-patient diversity was evident. The number of DGGE bands detected was not related to total viable microbial counts or the duration of intubation.Molecular profiling using DGGE demonstrated considerable biofilm compositional complexity and inter-patient diversity and provides a rapid method for the further study of biofilm composition in longitudinal and interventional studies. The presence of oral microorganisms in endotracheal tube biofilms suggests that these may be important in biofilm development and may provide a therapeutic target for the prevention of ventilator-associated pneumonia

Why we must reduce dental prescription of antibiotics: European Union Antibiotic Awareness Day

The prescription of antibiotics in dentistry is relatively small but nonetheless significant. With the emergence of bacterial species resistant to antibiotics there is a need to become vigilant about their prescription and with this, an urgent requirement for both professional and public understanding of the appropriate use of this life-saving component of treatment

The mouth as a window on the body

Historically, examination of the dorsum of the tongue has been considered a routine element of a medical assessment to provide a general indication of possible iron deficiency or pernicious anaemia. It is becoming increasing apparent, however, that the spectrum of changes within the mouth that reflect the presence of underlying illness is far greater than just an erythematous appearance of the tongue. In addition, in recent years attention has been given to the relationship between the dental health, the oral microflora and systemic disease. The mouth contains an extensive and diverse microbial community, involving more than 500 bacterial species. It is not surprising therefore, that microbial factors and inflammatory products within the periodontal tissues have an influence on systems at other body sites. The range of physical changes that may be observed in the mouth is relatively small, consisting of ulceration, blistering, white patches, erythema, swelling, pigmentation and lack of saliva. Whilst pain in the orofacial tissues is usually inflammatory and of localized dental origin, occasions do occur when pain may reflect the presence of a systemic condition