Antimicrobial resistance of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia in periodontitis patients

OBJECTIVES

Administration of systemic antimicrobials as an adjunct to mechanical treatment of periodontitis and sites with adverse clinical results leads to improved outcomes. This study aimed to assess the antimicrobial susceptibility of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia isolated from periodontitis patients to amoxicillin, metronidazole, azithromycin and moxifloxacin.

METHODS

A total of 76 patients diagnosed with generalised periodontitis were included in the study. Subgingival samples were processed by culture. Etest was used to determine susceptibility to amoxicillin, metronidazole, azithromycin and moxifloxacin.

RESULTS

A total of 141 isolates from 76 patients were evaluated, including 61 P. gingivalis, 43 T. forsythia and 37 A. actinomycetemcomitans. Etest results showed complete susceptibility of A. actinomycetemcomitans, P. gingivalis and T. forsythia to moxifloxacin. However, the isolates presented reduced susceptibility to the other antimicrobial agents investigated. Of the A. actinomycetemcomitans isolates, 70.3%, 40.5% and 89.2% were resistant to amoxicillin, azithromycin and metronidazole, respectively. The P. gingivalis samples showed relatively similar rates of resistance to amoxicillin (24.6%), azithromycin (21.3%) and metronidazole (24.6%). Similarly, 25.6%, 21.0% and 25.6% of the T. forsythia isolates were resistant to amoxicillin, azithromycin, and metronidazole, respectively.

CONCLUSION

These findings show that moxifloxacin may be a promising antimicrobial agent against P. gingivalis, T. forsythia and A. actinomycetemcomitans for the treatment of periodontitis. However, amoxicillin, azithromycin and metronidazole were less effective, especially against A. actinomycetemcomitans in vitro.

Antibiotic resistance of subgingival species in chronic periodontitis patients

BACKGROUND AND OBJECTIVE

The increasing rate of resistance of microorganisms to penicillin and other antibiotics has generated concern among health authorities in Latin America. The present investigation determined the in vitro susceptibility of Porphyromonas gingivalis, Fusobacterium nucleatum, black-pigmented Prevotella spp. and Aggregatibacter actinomycetemcomitans to metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin and moxifloxacin in patients with chronic periodontitis.

MATERIAL AND METHODS

Subgingival plaque samples from patients with periodontitis were collected and cultured on selective and nonselective culture media. The antimicrobial susceptibility of periodontopathogenic isolates was studied in chronic periodontitis patients in Colombia. Metronidazole, amoxicillin, amoxicillin/clavulanic acid, clindamycin and moxifloxacin were tested on all bacterial isolates and the percentage of resistant strains was calculated.

RESULTS

Of the 150 bacteria identified, 51 were P. gingivalis, 45 were black-pigmented Prevotella spp., 36 were F. nucleatum and 18 were A. actinomycetemcomitans. All the isolates were sensitive to amoxicillin/clavulanic acid and to moxifloxacin, but exhibited variable susceptibility patterns to the other antimicrobial agents tested.

CONCLUSION

The results of the present study suggest that periodontal microorganisms in patients with chronic periodontitis can be resistant to the antimicrobial agents commonly used in anti-infective periodontal therapy. We suggest that the indiscriminate use of antimicrobials could result in the appearance of more highly antibiotic-resistant strains of bacteria associated with periodontal diseases in our population compared with the populations of other countries.

Association between periodontal disease and plasma levels of cholesterol and triglycerides

Objective: Untreated periodontal disease seems to cause low grade systemic inflammation and blood lipid alteration leading to increased cardiovascular disease risk. To start testing this hypothesis in Colombian patients, a multicentre study was conducted including the three main state capitals: Bogotá, Medellín and Cali. Methods: In this study 192 (28.4%) advanced and 256 (37.8%) moderate periodontitis patients were investigated for socio-demographic variables, city of precedence, periodontal parameters, smoking, red complex periodontopathic bacteria, serum antibodies against Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans and blood lipids including total cholesterol, HDL, LDL and triglycerides (TG). Those parameters were compared to 229 (33.8%) controls having periodontal health or gingivitis. Results: Advanced periodontitis had worst periodontal indexes, than moderate periodontitis and controls. Interestingly, higher HDL and TG levels were present in periodontitis. BMI <30 and smoking were associated with increased HDL, HDL-35, LDL and TG, while glycemia >100 mg/dL associated with HDL, HDL-35 and TG. Tannerella forsythia showed a significant association with HDL-35 in bivariate analysis and serum IgG1 against P. gingivalis associated with HDL-35 and serum IgG1 against T. forsythia associated with TG and serum IgG2 against A. actinomycetemcomitans correlated with levels of HDL y HDL-35. In logistic regression the periodontitis patients from Cali presented reduced HDL levels as compared to Bogotá and Medellín patients. Presence of IgG1 antibodies against P. gingivalis and A. actinomycetemcomitans correlated with reduced HDL levels. Conclusion: This study confirmed that untreated periodontitis generates alteration in serum lipid levels and systemic bacterial exposure against important periodontopathic bacteria seems to be the biological link.

Comparison of serum amyloid A protein and C-reactive protein levels as inflammatory markers in periodontitis

PURPOSE

The purpose of this study was to compare serum amyloid A (SAA) protein levels with high-sensitive C-reactive protein (hs-CRP) levels as markers of systemic inflammation in patients with chronic periodontitis. The association of serum titers of antibodies to periodontal microbiota and SAA/hs-CRP levels in periodontitis patients was also studied.

METHODS

A total of 110 individuals were included in this study. Patients were assessed for levels of hs-CRP and SAA. Nonfasting blood samples were collected from participants at the time of clinical examination. The diagnosis of adipose tissue disorders was made according to previously defined criteria. To determine SAA levels, a sandwich enzyme-linked immunosorbent assay was utilized. Paper points were transferred to a sterile tube to obtain a pool of samples for polymerase chain reaction processing and the identification of Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, and Tannerella forsythia. The serum level of IgG1 and IgG2 antibodies to P. gingivalis, A. actinomycetemcomitans, and T. forsythia was also determined.

RESULTS

SAA and hs-CRP levels were higher in periodontitis patients than in controls (P<0.05). In bivariate analysis, high levels of hs-CRP (>3 mg/L) and SAA (>10 mg/L) were significantly associated with chronic periodontitis (P=0.004). The Spearman correlation analysis between acute-phase proteins showed that SAA positively correlated with hs-CRP (r=0.218, P=0.02). In the adjusted model, chronic periodontitis was associated with high levels of SAA (odds ratio [OR], 5.5; 95% confidence interval [CI], 1.6-18.2; P=0.005) and elevated hs-CRP levels (OR, 6.1, 95% CI, 1.6-23.6; P=0.008). Increased levels of serum IgG2 antibodies to P. gingivalis were associated with high levels of SAA (OR, 3.6; 95% CI, 1.4-8.5; P=0.005) and high concentrations of hs-CRP (OR, 4.3; 95% CI, 1.9-9.8; P<0.001).

CONCLUSIONS

SAA and hs-CRP concentrations in patients with chronic periodontitis are comparably elevated. High serum titers of antibodies to P. gingivalis and the presence of periodontal disease are independently related to high SAA and hs-CRP levels.

Association of metabolic syndrome and chronic periodontitis in Colombians

BACKGROUND

Metabolic syndrome (MetS) is a common chronic condition that increases the cardiovascular disease risk and is also linked to periodontitis. The study aim was to determine if a relationship exists between MetS and chronic periodontitis in adult Colombians.

METHODS

Participants were 220 healthy-gingivitis subjects and 431 periodontitis patients coming from the three largest Colombian cities. Periodontal status and MetS were determined in subjects. Univariate analysis and odds ratio were calculated within the 95 % confidence intervals and chi² test compared the groups. Variables were compared among the clinical periodontal groups and MetS by Wilcoxon and multivariate analysis, and logistic regression was performed for MetS and periodontitis.

RESULTS

MetS had higher prevalence in periodontitis group (6.3 %) versus controls (3.2 %). In multivariate analysis, periodontitis was associated with MetS (adjusted OR = 2.72, 95 % CI 1.09-6.79), glucose intolerance with another component of MetS (adjusted OR = 1.78, 1.16 to 2.72), glucose resistance (adjusted OR = 11.46, 95 % CI 1.41-92.88), smoking (OR = 1.72, 95 % CI 1.09-2.71), and city of origin (2.69, 95 % CI 1.79-4.04).

CONCLUSION

The study confirmed the positive association between MetS and periodontitis, being glucose sensitivity the strongly associated component.

CLINICAL RELEVANCE

MetS must be taken into account by the dentist when evaluating risk factors for periodontitis, being useful for dentists to evaluate glycemia, lipidic profile, central obesity, and high blood pressure in patients. Interdisciplinary treatment must be recommended when a patient with MetS and periodontitis is being treated.

Antibiotic resistance in periodontitis patients: A systematic scoping review of randomized clinical trials

OBJECTIVES

The objective of the study was to evaluate the prevalence and proportions of antibiotic-resistant species in periodontitis patients.

METHODS

A systematic scoping review of randomized clinical trials (RCTs) was conducted using the PRISMA extension for scoping reviews involving different databases. MeSH terms and keywords were provided to examine only RCTs with antibiotic-resistant results that included at least 3 months of follow-up of systematically healthy patients diagnosed with periodontitis and treated with systemic or local antibiotics adjunctive to subgingival debridement. RCTs that managed participants surgically, duplicate publications, and investigations implemented on animals were discarded.

RESULTS

Six RCTs were chosen. These studies included 465 patients. Most investigations observed that while Aggregatibacter actinomycetemcomitans, Tannerella forsythia, and Porphyromonas gingivalis had low resistance to amoxicillin, microorganisms in many sites showed resistance to tetracycline, metronidazole, and azithromycin pretreatment. A. actinomycetemcomitans showed high resistance to tetracycline pre- and post-therapy. The proportion of antibiotic-resistant samples augmented rapidly after the prescription of antibiotics in all test groups. The percentage of antibiotic-resistant microorganisms decreased over time; at the end of the follow-up period, resistance levels were close to baseline levels.

CONCLUSIONS

Adjunctive local and systemic antibiotic treatment temporarily increased the antibiotic resistance of subgingival microorganisms; nonetheless, many bacteria remained susceptible to antibiotics during their administration.

Prevalence and predictors for clinical attachment loss in adolescents in Latin America: cross-sectional study

AIM

To describe the prevalence, severity and extension of clinical attachment loss (CAL) and to study the predictors in 15- to 19-year-old adolescents from high schools in the Latin America.

MATERIALS AND METHODS

A cross-sectional, epidemiological study was performed. The sample included 1070 high school adolescents 15-19 years of age from Santiago de Chile (Chile), Buenos Aires, Córdoba, Mendoza (Argentina), Montevideo (Uruguay), Quito (Ecuador) and Medellín (Colombia). Calibrated examiners performed full mouth, six sites per tooth clinical examination.

RESULTS

There was a response rate of 100%. The prevalence of CAL ≥3 mm in ≥1 site was 32.6%, probing pocket depth ≥4 mm was 59.3% and bleeding on probing (BoP) ≥25% was 28.6%. The logistic regression analysis adjusted for cities revealed that smoking (OR = 1.6), attending public school (OR = 2.3) and having a BoP ≥25% (OR = 4.2) were positively associated with CAL ≥3 mm in ≥ 1 site.

CONCLUSION

Clinical attachment loss was prevalent in Latin America adolescents and it is associated with smoking, attendance public school and BoP.

Tannerella forsythia is associated with increased levels of atherogenic low density lipoprotein and total cholesterol in chronic periodontitis

Background

Accumulating evidence suggests that acute and chronic infections with periodontopathogens are associated with an increased risk of cardiovascular disease. The objective of this study was to assess whether Tanerella forsythia and Porphyromonas gingivalis are associated with increased levels of atherogenic low-density lipoprotein (LDL), high-density lipoprotein, total cholesterol (TC), triglycerides and body mass index (BMI) in chronic periodontitis patients.

Material and Methods

Medical history and clinical and radiographic examination were conducted in 80 chronic periodontitis patients and 28 healthy individuals. Fasting blood samples were drawn for the measurement of the parameters of dyslipidemia. Anthropometric measurements such as height in meters and weight in kilograms were recorded. Both periodontitis and control subjects were asked to answer a questionnaire with regard to their socio-demographic and smoking status. The presence of T. forsythia, and P. gingivalis was detected using primers designed to target the respective 16S rRNA gene sequences.

Results

The occurrence of T. forsythia and P. gingivalis was higher in the group of subjects with periodontitis. Superior levels of triglycerides were observed in chronic periodontitis patients compared to healthy individuals. High levels of TC in periodontitis persons were significantly associated with increased bleeding on probing. Greater mean levels of TC and LDL were shown in the presence of T. forsythia (P<0.05). Likewise, higher proportions of patients with BMI ≥25 kg/m2 related with T. forsythia (P<0.05). T. forsythia was a significant discriminating factor in the multivariate linear regression model emerging as significant explanatory of increased levels of TC (β=17,879, 95% CI = 4,357-31,401; p=0.01) and LDL (β=17,162, 95% CI= 4,009-30,316; p=0.01).

Conclusions

Higher levels of serum total cholesterol and LDL were observed in the occurrence of T. forsythia and the presence of this periodontopathogen may increase the atherogenic potency of low-density lipoprotein that may augment the risk for atherosclerosis in periodontal disease patients.

Key words:Periodontitis, dyslipidemia, Tannerella forsythia, cardiovascular disease.

Relationship between Gram negative enteric rods, Aggregatibacter actinomycetemcomitans, and clinical parameters in periodontal disease

BACKGROUND

The association between Gram negative enteric rods and Aggregatibacter actinomycetemcomitans in periodontal diseases has received little attention in the literature. The objective of this study was to explore the relationship between these organisms and clinical parameters of periodontal disease.

MATERIALS AND METHODS

Clinical parameters and occurrence of Gram-negative enteric rods and A. actinomycetemcomitans were examined in 76 patients with chronic periodontitis. Chi-square and Mann-Whitney tests were used to determine differences in clinical variables versus the presence or absence of both microorganisms. Correlation among both organisms and clinical data were determined using Spearman rank correlation coefficient.

RESULTS

Gram-negative enteric rods and A. actinomycetemcomitans were detected in 20 (26.3%) and 18 (23.7%) individuals, respectively. A total of 14 (18.4%) patients harbored both microorganisms studied. There were significantly positive correlations between enteric rods and presence of A. actinomycetemcomitans (r=0.652, P<0.0001). Both microorganisms were significant and positively correlated with probing depth (PD), clinical attachment level, and bleeding on probing (P<0.0001). The mean PD (mm) of the sampled sites was significantly deeper in patients with presence of A. actinomycetemcomitans and Gram-negative enteric rods.

CONCLUSION

The results of the present study suggest a strong positive correlation between Gram-negative enteric rods and A. actinomycetemcomitans in the population studied. This finding must be taken into account when considering the best therapeutic approach, including the utilization of antimicrobials. The adverse clinical outcomes observed in presence of these microorganisms could have implications in the pathogenesis of periodontal disease and a possible impact on outcomes after treatment.

Clinical Factors Influencing the Efficacy of Systemic Moxifloxacin in the Therapy of Patients With Generalized Aggressive Periodontitis: A Multilevel Analysis From a Clinical Trial

Background:

It has been reported that clinical results of mechanical periodontal treatment could differ between subjects and among different sites of the tooth in the patient. The objective of this multilevel analysis is to investigate clinical factors at subject and sites of the tooth that influence variations in clinical attachment (CAL) increase and probing depth (PD) diminution of adjunctive moxifloxacin (MOX) at six months post-treatment in generalized aggressive periodontitis.

Methods:

This clinical trial included 40 patients randomly distributed to two therapy protocols: scaling and root planing alone or combined with MOX. Multilevel linear models for continuous variables were formulated to evaluate the clinical impact of the hierarchical configuration of periodontal data.

Results:

Six months following therapy, the divergences between both protocols were statistically significant in PD diminution and CAL increase, favouring the MOX therapy (p<0.001). Besides, the multilevel analysis revealed that adjunctive MOX at the subject level, non-molar and the interaction non-molar x MOX at the tooth level, interproximal sites and the interaction interproximal sites x MOX at the site level, were statistically significant factors in determining CAL increase and PD diminution.

Conclusions:

The main cause of variability in CAL gain and PD reduction following adjunctive MOX was attributable to the tooth level. Adjunctive MOX and their interactions with non-molar and interproximal sites showed higher clinical benefits at the tooth and site levels which could be essential for PD reduction and CAL gain in generalized aggressive periodontitis subjects.

Accuracy of cotinine serum test to detect the smoking habit and its association with periodontal disease in a multicenter study

Background

The validity of the surveys on self-reported smoking status is often questioned because smokers underestimate cigarette use and deny the habit. It has been suggested that self-report should be accompanied by cotinine test. This report evaluates the usefulness of serum cotinine test to assess the association between smoking and periodontal status in a study with a large sample population to be used in studies with other serum markers in epidemiologic and periodontal medicine researches.

Material and Methods

578 patients who were part of a multicenter study on blood biomarkers were evaluated about smoking and its relation to periodontal disease. Severity of periodontal disease was determinate using clinical attachment loss (CAL). Smoking was assessed by a questionnaire and a blood sample drawn for serum cotinine determination.

Results

The optimal cut-off point for serum cotinine was 10 ng/ml. Serum cotinine showed greater association with severity of CAL than self-report for mild-moderate CAL [OR 2.03 (CI95% 1.16-3.53) vs. OR 1.08 (CI95% 0.62-1.87) ] advanced periodontitis [OR 2.36 (CI95% 1.30- 4.31) vs. OR 2.06 (CI95% 0.97-4.38) ] and extension of CAL > 3 mm [ OR 1.78 (CI95% 1.16-1.71) vs. 1.37 (CI95% 0.89-2.11)]. When the two tests were evaluated together were not shown to be better than serum cotinine test.

Conclusions

Self-reported smoking and serum cotinine test ≥ 10ng/ml are accurate, complementary and more reliable methods to assess the patient’s smoking status and could be used in studies evaluating serum samples in large population and multicenter studies. Clinical Relevance: The serum cotinine level is more reliable to make associations with the patient’s periodontal status than self-report questionnaire and could be used in multicenter and periodontal medicine studies.

Key words:Biological markers, serum, cotinine, periodontitis, smoking.

Association between odontoma size, age and gender: Multivariate analysis of retrospective data

Background

The variety of characteristics related to odontoma research, including an unexplored one such as size, merits a multivariate approach that allows the adequate drawing of inferences with pertinent conclusions. The objective of this study is to establish the possible association between some characteristics related to the odontoma, tumor size among them.

Material and Methods

The sociodemographic characteristics of 60 patients were evaluated. Diagnosis, size, location, type of treatment performed, and prognosis were determined. These data were analyzed descriptively and through multivariate models.

Results

Thirty-four compound and 26 complex odontomas in 32 men and 28 women were observed. The age average of patients was 15.6±11 years. Most of the odontomas presented a size inferior to 10 mm. A statistically significant association was observed between the routine radiographic finding and the absence of dental eruption (p=0.0001). The model of linear regression adjusted between odontoma size and age (β=0.321, p=0.01), as well as the model of logistic regression adjusted between gender (men) and tumor size (OR=12; 1.7 - 93 IC 95%, (p=0.01) were statistically significant.

Conclusions

Statistically significant associations between odontoma size and age, and between the male gender and odontomas smaller than 10 mm were found adjusting by other confounding variables. These results could grant clinicians a greater knowledge of the context of odontoma characteristics, which in turn could favor a better diagnostic and therapeutic decision-making.

Key words:Odontoma, compound odontoma, diagnosis, multivariate analysis.

Efficacy of three-dimensional models for medical education: A systematic scoping review of randomized clinical trials

To estimate the efficacy of three-dimensional (3D) models for medical education.

METHODS

A systematic scoping review was performed containing diverse databases such as SCOPUS, PubMed/MEDLINE, SCIELO, and LILACS. MeSH terms and keywords were stipulated to explore randomized clinical trials (RCTs) in all languages. Solely RCTs that accomplished the eligibility criteria were admitted.

RESULTS

Fifteen RCTs including 1659 medical students were chosen. Five RCTs studied heart models, 3 RCTs explored facial, spinal and bone fractures and the rest of the trials investigated eye, arterial, pelvic, hepatic, chest, skull, and cleft lip and palate models. Regarding the efficacy of 3D models, in terms of learning skills and knowledge gained by medical students, most RCTs reported higher scores. Considering the test-taking times, the results were variable. Two RCTs showed less time for the 3D group, another RCT indicated variable results in the response times of the test depending on the anatomical zone evaluated, while another described that the students in the 3D group were slightly quicker to answer all questions when compared with the traditional group, but without statistical significance. The other 11 experiments did not present results about test-taking times. Most students in all RCTs indicated satisfaction, enjoyment, and interest in utilizing the 3D systems, and recognized that their abilities were enhanced.

CONCLUSIONS

Higher efficacy in terms of learning skills and knowledge gained was observed when the 3D systems were used by medical students. Undergraduates also expressed great satisfaction with the use of these technologies. Regarding the test-taking times, the results favored the 3D group.

Social Context and Dental Pain in Adults of Colombian Ethnic Minority Groups: A Multilevel Cross-Sectional Study

AIMS

To estimate the effect of social context on dental pain in adults of Colombian ethnic minority groups (CEGs).

METHODS

Information from 34,843 participants was used. A multilevel model was constructed that had ethnic groups (ie, CEGs and non-CEGs) at level 1 and Colombian states at level 2. Contextual variables included gross domestic product (GDP), Human Development Index (HDI), and Unmet Basic Needs Index (UBNI).

RESULTS

Dental pain was observed in 12.3% of 6,440 CEGs. In an unadjusted logistic regression model, dental pain was associated with being a CEG (odds ratio [95% confidence interval], 1.34 [1.22-1.46]; P = .0001). This association remained significant after adjusting for possible confounding variables. An unconditional multilevel analysis showed that the variance in dental pain was statistically significant at the ethnic group level (β = 0.047 ± 0.015; P = .0009) and at the state level (β = 0.038 ± 0.019; P = .02) and that the variation between ethnic groups was higher than the variation between states (55% vs 45%, respectively). In a multivariate model, the variance in dental pain was also statistically significant at the ethnic group level (β = 0.029 ± 0.012; P = .007) and the state level (β = 0.042 ± .019; P = .01), but the variation between states was higher (40% vs 60%). The results of multilevel multivariate analyses showed that dental pain was associated with increasing age (β = 0.009 ± 0.001; P = .0001), lower education level (β = 0.302 ± 0.103; P = .0001), female sex (β = 0.031 ± 0.069; P = .003), GDP (β = 5.136 ± 2.009; P = .002) and HDI (β = 6.862 ± 5.550; P = .004); however, UBNI was not associated with dental pain.

CONCLUSION

The variance in dental pain was higher between states than between ethnic groups in the multivariate multilevel model. Dental pain in CEGs was associated with contextual and individual factors. Considering contextual factors, GDP and HDI may play a major role in dental pain prevalence.

Potential Clinical Application of Organs-on-a-Chip in Periodontal Diseases: A Systematic Review of In Vitro Studies

The periodontium is a unique organ from the standpoint of building an organ-on-a-chip (OoC) since it is a system that is continually threatened by microorganisms, their noxious compounds, and antigenic components. At the same time, periodontal health depends on a balanced connection between the host and the bacteria in the oral cavity, which is a complex micro-ecological environment. The objective of this systematic review of in vitro studies is to revise the potential clinical application of OoC in periodontal diseases. PRISMA was used to guide this analysis. The review framework made use of several databases, including SCOPUS, PubMed/MEDLINE, SCIELO, and LILACS as well as the gray literature. This systematic review comprised seven studies. The clinical efficacy of OoC in periodontal diseases was observed in models of the gingival crevice for the research of periodontitis, periodontal medication analysis, the interaction of multiple microbial species, pH measurements in in situ-grown biofilm, testing antimicrobial reagents, evaluation of mucosal interactions with microorganisms, and a device for quantitative exploration of microorganisms. OoC has the potential to advance our understanding of periodontal diseases by providing a more accurate representation of the oral microenvironment and enabling the development of new treatments.

Applications of Lab on a Chip in Antimicrobial Susceptibility of Staphylococcus aureus: A Systematic Review

Background and Objectives: Staphylococcus aureus is a prevalent bacterium capable of inducing various infections, including skin and soft tissue infections, bloodstream infections, pneumonia, and surgical site infections. The emergence of antimicrobial resistance in S. aureus, particularly methicillin-resistant S. aureus, has raised substantial concerns within global healthcare settings. Prior to antibiotic prescription, the ideal approach is antimicrobial susceptibility testing (AST); however, this is frequently perceived as excessively complex and time-intensive. Lab-on-a-chip (LOC) technology holds promise in addressing these challenges and advancing fundamental microbiological research while also aiding in the development of therapeutic strategies. This systematic review aims to evaluate the potential utility of LOC for AST of S. aureus. Materials and Methods: This study adhered to the PRISMA guidelines. Various databases, including SCOPUS, PubMed/MEDLINE, SCIELO, and LILACS, in addition to gray literature sources, were employed in the review process. Results: Sixteen studies were included in this systematic review. All these studies detailed the effectiveness, rapidity, and predictability of LOC systems for assessing S. aureus susceptibility to various antibiotics. When comparing the LOC approach to traditional manual methods, it was evident that LOC requires a minimal quantity of reagents. Furthermore, most studies reported that the entire LOC procedure took 10 min to 7 h, with results being equally accurate as those obtained through traditional AST protocols. Conclusions: The potential application of LOC for AST of S. aureus is emphasized by its ability to provide rapid access to minimum inhibitory concentration data, which can substantially aid in selecting the most suitable antibiotics and dosages for treating challenging infections caused by this microorganism. Moreover, the rapid AST facilitated by LOC holds promise for enhancing the appropriateness and efficacy of therapy in clinical settings.

Moxifloxacin versus amoxicillin plus metronidazole as adjunctive therapy for generalized aggressive periodontitis: a pilot randomized controlled clinical trial

OBJECTIVE

Adjunctive antimicrobials improve probing depth and clinical attachment loss compared with subgingival debridement (SD) alone in patients with aggressive periodontitis. The microbiologic and clinical effectiveness of moxifloxacin (MOX) and amoxicillin plus metronidazole (AMOX+ME) as adjunctive therapies for generalized aggressive periodontitis were compared.

METHOD AND MATERIALS

This pilot randomized controlled clinical trial included 36 patients who were assigned to one of three therapy groups: SD plus systemic MOX (400 mg QD for 7 days), SD plus systemic AMOX+ME (500 mg TID each for 7 days), or SD plus placebo. Probing depth, clinical attachment loss, bleeding on probing, and plaque were recorded at baseline and 3 and 6 months after treatment. Subgingival plaque samples were analyzed.

RESULTS

All treatments resulted in significant probing depth and clinical attachment loss reduction compared with the baseline values (P < .0001 for all), with the effects still present at 6 months posttreatment, but the patients taking antibiotic protocols presented the most significant gains (P < .0001). There was a significant reduction in the occurrence of gingival pockets ≥ 6 mm at 6 months in all treatment groups (P < .0001), favoring the MOX and AMOX+ME groups. Adjunctive MOX diminished subgingival Aggregatibacter actinomycetemcomitans to unnoticeable stages, after the follow-up period. Adverse events were noted only in some patients of the AMOX+ME group.

CONCLUSIONS

This pilot clinical trial proposes that using MOX and AMOX+ME as adjuncts to SD improves the clinical and microbiologic parameters in comparison to mechanical therapy alone; however, the MOX protocol did not cause adverse events and decreased subgingival A actinomycetemcomitans to imperceptible levels.

Comparison of frictional forces during the closure of extraction spaces in passive self-ligating brackets and conventionally ligated brackets using the finite element method

Background

This study compared the frictional force resulting from the bracket/archwire interface and the stress at the root/periodontal ligament/bone interface, between passive self-ligating brackets and conventionally ligated brackets, during the space closure stage.

Material and Methods

A cone beam tomography was taken to a female patient that required extraction of upper first premolars and passive self-ligating system; three months after its activation, a cone beam tomography was taken again. The designs of the maxillary bone and the entire system were possible through tomography images and stereomicroscopic photographs. Validation of the Finite Element Method (FEM) was achieved comparing the amount of movement seen through tomography images and the FEM. Space closure was simulated for each system through the FEM and a comparison was made between the frictional force at the bracket/archwire interface, and the root/periodontal ligament/bone interface.

Results

The most significant representation of frictional force at bracket/archwire interface and bone stress was found at the conventionally ligated system, while the passive self-ligating system accounted for the highest distribution of stress over the root.

Conclusions

The FEM is an accurate tool used to quantify frictional force and stress concentration during the orthodontic closure. The passive self-ligating system was seen less frictional during the closure state compared to conventional brackets.

Key words:Friction, orthodontic bracket, finite element analysis.