Do the oral Staphylococcus aureus strains from denture wearers have a greater pathogenicity potential?

Enhancing Presurgical Infant Orthopedic Appliances: Characterization, Mechanics, and Biofilm Inhibition of a Novel Chlorhexidine-Halloysite Nanotube-Modified PMMA

Objectives

This in vitro study aimed to develop a novel nanocomposite acrylic resin with inherent antimicrobial properties. This study evaluated its effectiveness against microbial biofilm formation, while also assessing its physical and mechanical properties.

Methods

Polymethylmethacrylate (PMMA) was modified with four different concentrations of chlorhexidine halloysite nanotubes (CHX-HNTs): 1%, 1.5%, 3%, and 4.5 wt.% by weight, along with a control group (0 wt.% CHX-HNTs). The biofilm inhibition ability of the modified CHX-HNTs acrylic against Candida albicans, Staphylococcus aureus, Streptococcus pneumoniae, and Streptococcus agalactiae was assessed using microtiter biofilm test. In addition, ten samples from each group were then tested for flexural strength, surface roughness, and hardness. Statistical analysis was performed using one-way ANOVA and Tukey's test for comparison (P < 0.05).

Results

CHX-HNTs effectively reduced the adhesion of Candida albicans and bacteria to the PMMA in a dose-dependent manner. The higher the concentration of CHX-HNTs, the greater the reduction in microbial adhesion, with the highest concentration (4.5 wt.%) showing the most significant effect with inhibition rates ≥98%. The addition of CHX-HNTs at any tested concentration (1%, 1.5%, 3%, and 4.5 wt.%) did not cause any statistically significant difference in the flexural strength, surface roughness, or hardness of the PMMA compared to the control group.

Conclusions

The novel integration of CHX-HNT fillers shows promising results as an effective biofilm inhibitor on acrylic appliances. This new approach has the potential to successfully control infectious diseases without negatively affecting the mechanical properties of the acrylic resin. Clinical Relevance. The integration of CHX-HNTs into presurgical infant orthopedic appliances should be thoroughly assessed as a promising preventive measure to mitigate microbial infections. This evaluation holds significant potential for controlling infectious diseases among infants with cleft lip and palate, thereby offering a valuable contribution to their overall well-being.

Effectiveness of Oral Cephalexin-Clavulanic Acid, Cefuroxime, and Amoxicillin-Clavulanic Acid in the Management of Dental Infections: A Real-World, Retrospective, Electronic Medical Record-Based Study in India

BACKGROUND

Despite multiple antibiotics being available to manage dental infections (DI), there is lack of data comparing commonly prescribed antibiotics in India.

OBJECTIVES

The aim of this study was to evaluate the real-world effectiveness and tolerability of cephalexin-clavulanic acid fixed-dose combination (cephalexin CV FDC) in contrast with amoxicillin-clavulanic acid (co-amoxiclav FDC) and cefuroxime among patients with dental infections (odontogenic) in India.

METHODS

This retrospective, multi-centric, observational, real-world electronic medical record (EMR)-based study was conducted between January 2022 and December 2022. The EMRs of 355 adults with DI receiving oral cephalexin CV, co-amoxiclav, or cefuroxime were categorized into two distinct groups: Group I (Test Group) with patients prescribed cephalexin extended release 375/750 mg along with clavulanic acid 125 mg; and Group II (Comparator Group) with patients prescribed co-amoxiclav 625 mg (500 mg amoxicillin + 125 mg clavulanic acid) or cefuroxime (250 mg/500 mg).

RESULTS

Toothache was the most common complaint, reported by 95.5% of patients, followed by swelling (46.8%), tooth sensitivity (35.5%), pus discharge (33.0%), redness and halitosis (30.4% each). Dental caries was observed in 81.1% of patients. Clinical improvement, defined as improvement/partial resolution of infection-related clinical signs and symptoms (composite measure of pain, swelling, fever, requirement of additional antimicrobial therapy) as per dentists' judgment, was recorded in 98.3% of patients with cephalexin CV, 96.8% of patients with co-amoxiclav, and 98.9% of patients treated with cefuroxime within 10 days. Time (days) to clinical improvement was numerically lesser among patients receiving cephalexin CV (4.6 ± 2.0) compared with cefuroxime (4.9 ± 2.1) and co-amoxiclav (5.0 ± 2.6). All treatments were well tolerated.

CONCLUSION

Cephalexin CV was as effective as co-amoxiclav and cefuroxime, with faster clinical improvement and better resolution of certain symptoms.

Assessment of usefulness and reliability of YouTube™ videos on denture care

INTRODUCTION

The world's population is in a demographic transition with a rising ageing population. Tooth loss is frequent among older people resulting in the replacement of natural teeth using complete or partial dentures. YouTube™ is the second most popular website in the world and is being increasingly used to access health care information. The aim of this study is to evaluate the usefulness and reliability of the information in YouTube™ videos regarding denture care.

METHODS

The YouTube™ website was used to systematically search for videos using the keyword 'denture care'. Videos meeting the eligibility criteria were assessed separately by two independent researchers. The usefulness of the videos was assessed using the Global Quality Assessment Scale and a customized usefulness scoring scheme. Based on these scores, the usefulness of the videos was categorized as low, medium and high. A modified DISCERN tool (mDISCERN) was used for assessing reliability with scores ranging from 0 to 5. Other video characteristics like source/ownership of the videos, duration, views, likes, dislikes, number of days posted, like ratio, view ratio, interaction index and Video Power Index were also obtained. Statistical analysis was carried out using the Kruskal-Wallis test, Spearman correlation test and multiple linear regression analysis.

RESULTS

A total of 120 videos were included. Based on the usefulness score, the usefulness of 65.8% of videos were classified as low, 32.5% were medium and 1.6% had high usefulness. The mDISCERN score for 74.2% of videos was 2 or below 2 indicating that the majority of videos had low reliability. Video characteristics did not differ significantly according to the usefulness of videos. Videos uploaded by dentists or dental hygienists had significantly higher usefulness scores (p < 0.001) in comparison to videos uploaded by other sources. However, reliability scores did not differ based on the sources of the videos. Video reliability was found to have a significant (B = 2.08, p < 0.001) positive association with video usefulness.

CONCLUSION

YouTube™ cannot be recommended as the only source of information for denture care as most videos received low usefulness and reliability ratings in our study. Dentists and dental health professionals could take an active part in enhancing denture care-related content on YouTube™ and enable patients to have adequate and reliable knowledge of denture hygiene practices.

An organotypic oral mucosal infection model to study host-pathogen interactions

Early in vitro oral mucosal infection models (OMMs) failed to consider the suitability of the model environment to represent the host immune response. Denture stomatitis (DS) is mediated by Candida albicans, but the role of Staphylococcus aureus remains uncertain. A collagen hydrogel-based OMM containing HaCaT and HGF cell types was developed, characterised and employed to study of tissue invasion and pro-inflammatory cytokine production in response to pathogens. Models formed a robust epithelium. Despite their inflammatory baseline, 24-h infection with C. albicans, and/or S. aureus led to tissue invasion, and significantly upregulated IL-6 and IL-8 production by OMMs when compared to the unstimulated control. No significant difference in IL-6 or IL-8 production by OMMs was observed between single and dual infections. These attributes indicate that this newly developed OMM is suitable for the study of DS and could be implemented for the wider study of oral infection.

Staphylococcus aureus Isolated from the Oral Cavity: Phage Susceptibility in Relation to Antibiotic Resistance

Nowadays, research on bacteriophage therapy and its potential use in combination with antibiotics has been gaining momentum. One hundred and ten oral Staphylococcus aureus isolates were phage-typed and their antibiotic resistance was determined by standard and molecular methods. The prevalence of MSSA and MRSA strains was 89.1% and 10.9%, respectively. Nearly all (91.8%) analyzed isolates, whether MSSA or MRSA, were susceptible to the phages used from the international set. The highest lytic activity showed phages 79 and 52 A from lytic group I. The predominant phage groups were mixed, the I+III group and a mixed group containing phages from at least three various lytic groups. S. aureus strains sensitive to phage group I were usually resistant to penicillin and susceptible to ciprofloxacin, whereas the strains typeable with group V or group V with the 95 phage were susceptible to most antibiotics. Epidemic CA-MRSA strains (SCCmecIV) of phage type 80/81 carried Panton–Valentine leucocidin genes. Considering the high sensitivity of oral S. aureus to the analyzed phages and the promising results of phage therapies reported by other authors, phage cocktails or phage-antibiotic combinations may potentially find applications in both the prevention and eradication of staphylococcal infections.

Influence of Bioinspired Lithium-Doped Titanium Implants on Gingival Fibroblast Bioactivity and Biofilm Adhesion

Soft tissue integration (STI) at the transmucosal level around dental implants is crucial for the long-term success of dental implants. Surface modification of titanium dental implants could be an effective way to enhance peri-implant STI. The present study aimed to investigate the effect of bioinspired lithium (Li)-doped Ti surface on the behaviour of human gingival fibroblasts (HGFs) and oral biofilm in vitro. HGFs were cultured on various Ti surfaces—Li-doped Ti (Li_Ti), NaOH_Ti and micro-rough Ti (Control_Ti)—and were evaluated for viability, adhesion, extracellular matrix protein expression and cytokine secretion. Furthermore, single species bacteria (Staphylococcus aureus) and multi-species oral biofilms from saliva were cultured on each surface and assessed for viability and metabolic activity. The results show that both Li_Ti and NaOH_Ti significantly increased the proliferation of HGFs compared to the control. Fibroblast growth factor-2 (FGF-2) mRNA levels were significantly increased on Li_Ti and NaOH_Ti at day 7. Moreover, Li_Ti upregulated COL-I and fibronectin gene expression compared to the NaOH_Ti. A significant decrease in bacterial metabolic activity was detected for both the Li_Ti and NaOH_Ti surfaces. Together, these results suggest that bioinspired Li-doped Ti promotes HGF bioactivity while suppressing bacterial adhesion and growth. This is of clinical importance regarding STI improvement during the maintenance phase of the dental implant treatment.

Distribution and antibiotic-resistance of different Staphylococcus species identified by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) isolated from the oral cavity

Background: The use of antibiotics in dentistry is associated with the emergence and spread of antibiotic-resistant microorganisms, including commensal staphylococci.

Methods: A total of 367 oral samples were collected, from which staphylococci were isolated and identified by using matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF). The antibiotic susceptibility of the isolates was determined and molecular characteristics for methicillin-resistant staphylococci was performed.

Results: A total of 103 coagulase-negative staphylococci (CoNS), among them S. warneri, S. haemolyticus, S. saprophyticus, S. pasteuri, S. epidermidis, S. hominis, S. xylosus, S. equorum, S. kloosii, S. succinus, S. cohnii, and S. simulans, were confirmed by MALDI-TOF. Resistance to most tested antibiotics was statistically higher in CoNS than in S. aureus isolates (P-value < 0.05). CoNS isolates showed high resistance to penicillin (S. saprophyticus 88.9%), erythromycin (S. haemolyticus 84.6%), fusidic acid (S. saprophyticus 77.8%), co-trimoxazole (S. epidermidis 71.4%), gentamicin (S. warneri 63.8%), and tetracycline (S. saprophyticus 55.6%). Multidrug resistance was largely observed, especially among S. haemolyticus and S. saprophyticus species. Methicillin-resistance in S. haemolyticus (38.5%), S. saprophyticus (22.2%) and S. aureus (13.5%) was associated with the presence of the mecA gene and SCCmec type IV or V.

Conclusion: Coagulase-negative staphylococci, especially S. haemolyticus and S. saprophyticus, seem to be a reservoir of methicillin resistance and multidrug resistance in the oral cavity.

COVID-19 in dental care: What do we know?

SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) is primarily transmitted by airborne droplets and its spread is favored by close human contact, thus the COVID-19 pandemic is the new challenge in dental practice. The oral cavity was considered as a SARS-CoV-2 reservoir, the viruses were detected in the saliva and periodontal pockets of infected persons. Therefore, aside from the most common symptoms, COVID-19 can manifest as lesions in the oral cavity. Due to the high risk of cross-contamination in the dental office, new precautionary measures were implemented in professional dental care to ensure safety for both, dental staff and patients. Given the dynamically changing situation, dental practitioners should follow local guidelines and implement them according to current needs and available resources. The key to success is to reduce the risk of cross-infection with SARS-CoV-2 at no cost to the good oral health of the population.

Establishment of the reference intervals of whole blood neutrophil phagocytosis by flow cytometry

Objective

To investigate the reference intervals (RIs) of the whole blood neutrophil phagocytosis by flow cytometry (FCM) and to study the application value of neutrophil phagocytosis in infectious diseases.

Methods

Pathogens (Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923) cultured for 18–24 h were labeled by fluorescence probe carboxyfluorescein diacetate succinimidyl ester (CFDA‐SE), and then incubated with whole blood at 37℃. The phagocytosis of pathogens by neutrophils was detected by flow cytometry, and a reference interval was established.

Results

In the healthy adults, the reference interval for the neutrophil phagocytosis to Escherichia coli was 46.91%–83.09% and to Staphylococcus aureus was 33.92%–69.48%. This method showed good reproducibility. Neutrophil phagocytosis was negatively correlated with the neutrophil count, neutrophil percentage, and neutrophil‐to‐lymphocyte ratio (NLR, p < 0.05).

Conclusion

We have successfully established the RIs of neutrophil phagocytosis in whole blood in healthy adults by flow cytometry (FCM), which might be of important clinical value in the diagnosis, treatment, and prognosis of infectious diseases.

Presence of egc-positive major clones ST 45, 30 and 22 among methicillin-resistant and methicillin-susceptible oral Staphylococcus aureus strains

The oral cavity may comprise a significant reservoir for Staphylococcus aureus but the data on molecular epidemiology and clonal distribution of oral strains are really scarce. This study aimed to evaluate the clonal relatedness in S. aureus isolated from oral cavity and their relationship with carriage of virulence genes, and antimicrobial resistance profiles. A total of 139 oral S. aureus isolates were obtained from 2327 analysed oral samples of dental patients. Antimicrobial susceptibility testing was performed. Isolates were characterized using protein A gene (spa) typing, spa-CC clonal complexes, toxin genes and SCCmec typing for MRSA. High resistance rates for penicillin, tetracycline and gentamicin were detected, respectively 58.3%, 42.4%, and 35.2%. Twelve (8.6%) S. aureus isolates were identified as MRSA. All of MRSA isolates were mecA-positive and mecC-negative. SCCmec IV was the most common type (66.7%), which was typical for community-acquired MRSA (CA-MRSA). Overall, the enterotoxin gene cluster (egc) was the most frequent detected virulence factor (44.9%), both in MSSA and MRSA isolates. Presence of genes encoding for the enterotoxins (sea, seb, sec, seh, sek), exfoliative toxin A (eta), and toxic shock syndrome toxin-1 (tst) was also observed. Strains carrying lukS-PV/lukF-PV genes belonged to SCCmecV- spa type t437. The most prevalent spa types were t091, t015, t084, t002, t571, and t026 among all 57 identified. Spa types, including 3 new ones, grouped in 6 different spa-CC clonal complexes, with four major dominated; CC45, CC30, CC5, and CC15. This study demonstrated that both methicillin-susceptible and methicillin-resistant major European clones of S. aureus could be isolated from the oral cavity of dental patients, with the emergence of PVL-positive CA-MRSA strains. The oral cavity should be considered as a possible source of toxigenic egc-positive S. aureus strains, in terms of potential risk of cross-infection and dissemination to other body sites.

Possible Uses of Plants of the Genus Asphodelus in Oral Medicine

Among the many plants used in traditional medicine we have the plants of the genus Asphodelus, which are present in the Mediterranean area in North Africa and South East Asia, and have been used by indigenous peoples until recently for various pathologies, including: Psoriasis, alopecia areata, acne, burns, nephrolithiasis, toothache, and local inflammation. The scientific literature over the last five years has investigated the various effects of the metabolites extracted from plants of the genus Asphodelus, paying attention to the diuretic, antihypertensive, antimicrobial, anti-inflammatory, and antioxidant effects, and it also has begun to investigate the antitumor properties on tumor cell lines. Studies have been identified through bibliographic research on electronic databases. A total of 574 records were identified on the PubMed, Scopus, Web of Science, and EBSCO databases. After having proceeded to the screening of the articles with the application of the eligibility criteria (all the articles pertaining to the issue Asphodelus), we arrived at a number of 163 articles, and then after the elimination of overlaps, to 82 articles. There are 11 articles which investigate the possible uses of plants of the genus Asphodelus in oral medicine. In oral medicine, the possible uses investigated by the scientific literature are for the treatment of neoplastic (melanoma and oral cancer), viral (herpetic viruses), and microbial diseases (candida, bacteriosis, leishmaniasis), and in the affection of the skin.