Saliva, supragingival biofilm and root canals can harbor gene associated with resistance to lactamic agents

Bypass gastroplasty impacts oral health, salivary inflammatory biomarkers, and microbiota: a controlled study

OBJECTIVES

Knowledge about the impact of gastroplasty on oral health and salivary biomarkers is limited. The aim was to prospectively evaluate oral health status, salivary inflammatory markers, and microbiota in patients undergoing gastroplasty compared with a control group undergoing a dietary program.

MATERIALS AND METHODS

Forty participants with obesity class II/III were included (20 individuals in each sex-matched group; 23-44 years). Dental status, salivary flow, buffering capacity, inflammatory cytokines, and uric acid were assessed. Salivary microbiological analysis (16S-rRNA sequencing) assessed the abundance of genus, species, and alpha diversity. Cluster analysis and mixed-model ANOVA were applied.

RESULTS

Oral health status, waist-to-hip ratio, and salivary alpha diversity were associated at baseline. A subtle improvement in food consumption markers was observed, although caries activity increased in both groups, and the gastroplasty group showed worse periodontal status after three months. IFNγ and IL10 levels decreased in the gastroplasty group at 3 months, while a decrease was observed in the control group at 6 months; IL6 decreased in both groups (p < 0.001). Salivary flow and buffering capacity did not change. Significant changes in Prevotella nigrescens and Porphyromonas endodontalis abundance were observed in both groups, while alpha diversity (Sobs, Chao1, Ace, Shannon, and Simpson) increased in the gastroplasty group.

CONCLUSIONS

Both interventions changed in different degrees the salivary inflammatory biomarkers and microbiota, but did not improve the periodontal status after 6 months.

CLINICAL RELEVANCE

Although the observed discrete improvement in dietary habits, caries activity increased with no clinical improvement in the periodontal status, emphasizing the need of oral health monitoring during obesity treatment.

The impact of dental care intervention on ventilator-associate events: A Quasi-experimental study

BACKGROUND

This study aimed to evaluate a multidisciplinary intensive oral health protocol, proposed and applied by a dentist, in an adult Intensive Care Unit (ICU), in regards to the prevention of Ventilator-associated Pneumonia (VAP), compared with retrospective data.

METHODS

4,103 patients admitted to the adult ICU from January 2013 to December 2017 and selected patients who were under mechanical ventilation with an orotracheal tube for at least 48 hours. These patients were compared before (Baseline Group) and after (Intervention Group) the hygiene protocol established and carried out by a multidisciplinary team led by a dentist. The Baseline Group, from January 2013 to May 2015, 213 patients, and the Intervention Group, from June 2015 to December 2017, 137 patients.

RESULTS

Forty-five patients (21.12%) in the Baseline Group and 5 patients (3.65%) in the Intervention Group developed VAP (P < .05). Twenty-two patients (10.33%) died due to VAP in the Baseline Group, and 1 patient (0.73%) died due to VAP (P < .05) in the Intervention Group. The mortality rate of  VAP was 48.89% for Baseline Group and 20.00% for Intervention Group (P > .05).

CONCLUSIONS

The study showed better outcomes when patients' oral health is led, evaluated and treated by a dentist in the ICU. The dental care intervention contributed to the reduction of VAP episodes and deaths due to VAP.

Microbial ecology and predicted metabolic pathways in various oral environments from patients with acute endodontic infections

AIM

To assess in a cross-sectional clinical study the effect of antibiotics on the diversity, structure and metabolic pathways of bacterial communities in various oral environments in patients with acute primary infections.

METHODOLOGY

Samples of saliva (SA), supragingival biofilm (SB) and from the pulp cavity (PC) were collected from teeth with acute primary infections and then grouped according to previous use of antibiotics (NoAtb = no antibiotics [n = 6]; Atb = antibiotics [n = 6]). DNA sequencing was conducted using MiSeq (Illumina, San Diego, CA, USA). The V1-V3 hyper-variable region of the 16S rRNA gene was amplified. A custom Mothur pipeline was used for 16S rRNA processing. Subsequent analyses of the sequence dataset were performed in R (using vegan, phyloseq and ggplot2 packages) or QIIME.

RESULTS

Twelve patients aged from 22 to 56 years were recruited. Participants in the Atb group had taken the beta-lactamics amoxicillin (5/6) or cephalexin (1/6) for 2-3 days. A total of 332 bacterial taxa (OTUs) were identified, belonging to 120 genera, 60 families and nine phyla. Firmicutes (41%) and Bacteroidetes (38%) were the most abundant phyla in all samples. Taxa clustered significantly by oral site (PCoA analysis; P < 0.05, ANOSIM). Use of antibiotics had little effect on this clustering. However, SA, SB and PC had different degrees of richness, diversity and evenness. The greatest diversity was observed in SB samples and the least diversity was observed in PC samples. Metabolic prediction identified 163 pathways and previous use of antibiotics had a major effect on the estimated functional clustering in SA and PC samples.

CONCLUSION

The ecological niche had a strong influence on the bacterial content of samples from various oral sites. Previous exposure to antibiotics may exert an effect on the phylogenetic composition of SA. Metabolic pathways appear to be modulated by antimicrobial agents in SA and PC samples. The dynamics of host/microbial interactions in the apical region and the functional ecology of the infected pulp cavity should be revisited.

Drug Resistance and Gene Transfer Mechanisms in Respiratory/Oral Bacteria

Growing evidence suggests the existence of new antibiotic resistance mechanisms. Recent studies have revealed that quorum-quenching enzymes, such as MacQ, are involved in both antibiotic resistance and cell-cell communication. Furthermore, some small bacterial regulatory RNAs, classified into RNA attenuators and small RNAs, modulate the expression of resistance genes. For example, small RNA sprX, can shape bacterial resistance to glycopeptide antibiotics via specific downregulation of protein SpoVG. Moreover, some bacterial lipocalins capture antibiotics in the extracellular space, contributing to severe multidrug resistance. But this defense mechanism may be influenced by Agr-regulated toxins and liposoluble vitamins. Outer membrane porin proteins and efflux pumps can influence intracellular concentrations of antibiotics. Alterations in target enzymes or antibiotics prevent binding to targets, which act to confer high levels of resistance in respiratory/oral bacteria. As described recently, horizontal gene transfer, including conjugation, transduction and transformation, is common in respiratory/oral microflora. Many conjugative transposons and plasmids discovered to date encode antibiotic resistance proteins and can be transferred from donor bacteria to transient recipient bacteria. New classes of mobile genetic elements are also being identified. For example, nucleic acids that circulate in the bloodstream (circulating nucleic acids) can integrate into the host cell genome by up-regulation of DNA damage and repair pathways. With multidrug resistant bacteria on the rise, new drugs have been developed to combate bacterial antibiotic resistance, such as innate defense regulators, reactive oxygen species and microbial volatile compounds. This review summaries various aspects and mechanisms of antibiotic resistance in the respiratory/oral microbiota. A better understanding of these mechanisms will facilitate minimization of the emergence of antibiotic resistance.

Is it necessary to have a dentist within an intensive care unit team? Report of a randomised clinical trial

OBJECTIVE

To evaluate the effectiveness of dental treatment in improving oral health in critical patients.

METHODS

This randomised clinical trial was conducted in a general intensive care unit (ICU) at a tertiary care public facility from 1 January 2011 to 8 August 2013. Data from 254 adult patients staying in the ICU for 48 hours or more were analysed. The experimental group (n = 127) had access to dental treatment provided by a dentist four to five times a week, in addition to routine oral hygiene, whereas the control group (n = 127) had access only to routine oral hygiene, including topical application of chlorhexidine, provided by the ICU nursing staff. The baseline oral health status of the enrolled patients was poor and included edentulism, caries, gingivitis, periodontitis and residual roots. Dental treatment consisted of toothbrushing, tongue scraping, removal of calculus, scaling and root planing, caries restoration and tooth extraction.

RESULTS

The Oral Hygiene Index Simplified (OHI-S) and Gingival Index (GI) scores decreased in the experimental group but did not change significantly in the control group during the ICU stay. Dental treatment prevented most of the episodes of respiratory tract infections, as previously reported. No severe adverse events from the dental treatment were observed.

CONCLUSION

From an interprofessional perspective, our results support the idea of including dentists in the ICU team to improve oral health in critical patients and effectively prevent respiratory tract infections, in addition to the improvement achievable by applying chlorhexidine alone.

Contamination Controls for Analysis of Root Canal Samples by Molecular Methods: An Overlooked and Unsolved Problem

INTRODUCTION

It has been almost 20 years since molecular methods were first described for the analysis of root canal microbial flora. Contamination control samples are essential to establish DNA decontamination before taking root canal samples, and this review assessed those studies.

METHODS

Using PubMed, a search was conducted for studies using molecular microbial analysis for the investigation of endodontic samples. Studies were grouped according to the cleaning protocol, acquisition methods, and processing of control samples taken to check for contamination.

RESULTS

Of 136 studies applying molecular analysis to root canal samples, 21 studies performed surface cleaning and checking nucleotide decontamination with contamination control samples processed by polymerase chain reaction. Only 1 study described disinfection, sampling from the access cavity, and processing by polymerase chain reaction and reported the result; that study reported that all samples contained contaminating bacterial DNA.

CONCLUSIONS

Cleaning, disinfection, and checking for contamination are basic scientific prerequisites for this type of investigation; yet, this review identifies it as an overlooked issue. On the basis of this review, we call for improved scientific practice in this field.