Oral microflora and selection of resistance after a single dose of amoxicillin

Antibiotic prophylaxis dysregulates dental implant placement surgery-induced osteoimmune wound healing and attenuates the alveolar bone-implant interface in mice

AIM

Antimicrobial-induced shifts in commensal oral microbiota can dysregulate helper T-cell oral immunity to affect osteoclast-osteoblast actions in alveolar bone. Antibiotic prophylaxis is commonly performed with dental implant placement surgery to prevent post-surgical complications. However, antibiotic prophylaxis effects on osteoimmune processes supporting dental implant osseointegration are unknown. The aim of the study was to discern the impact of antibiotic prophylaxis on dental implant placement surgery-induced osteoimmune wound healing and osseointegration.

MATERIALS AND METHODS

We performed SHAM or dental implant placement surgery in mice. Groups were administered prophylactic antibiotics (amoxicillin or clindamycin) or vehicle. Gingival bacteriome was assessed via 16S sequencing. Helper T-cell oral immunity was evaluated by flow cytometry. Osteoclasts and osteoblasts were assessed via histomorphometry. Implant osseointegration was evaluated by micro-computed tomography.

RESULTS

Dental implant placement surgery up-regulated TH 1, TH 2 and TREG cells in cervical lymph nodes (CLNs), which infers helper T-cell oral immunity contributes to dental implant placement osseous wound healing. Prophylactic antibiotics with dental implant placement surgery caused a bacterial dysbiosis, suppressed TH 1, TH 2 and TREG cells in CLNs, reduced osteoclasts and osteoblasts lining peri-implant alveolar bone, and attenuated the alveolar bone-implant interface.

CONCLUSIONS

Antibiotic prophylaxis dysregulates dental implant placement surgery-induced osteoimmune wound healing and attenuates the alveolar bone-implant interface in mice.

Utilizing a Questionnaire to Implement a Risk-based Antibiotic Prophylaxis Protocol for Transrectal Prostate Biopsy

OBJECTIVE

To develop and evaluate a risk-based antibiotic prophylaxis protocol for patients undergoing transrectal prostate biopsy.

METHODS

We created a risk-based protocol for antibiotic prophylaxis before transrectal prostate biopsy. Patients were screened for infection risk-factors with a self-administered questionnaire. The protocol was implemented from January 1, 2020 to March 31, 2020. We compared patient risk-factors, antibiotic regimens, and 30-day infection rates for patients undergoing transrectal prostate biopsies during the intervention and for a 3-month period before the intervention.

RESULTS

There were 116 prostate biopsies in the preintervention group and 104 in the intervention group. Although there was no significant difference in the number of high-risk patients between the 2 groups (48% vs 55%; P = .33), the percentage of patients treated with augmented prophylaxis decreased from 74% to 45% (P = 0.03). The duration of antibiotic administration and the median number of doses prescribed also decreased significantly. Despite significant decreases in antibiotic use, there were no differences in infection rates (5% vs 5%; P = .90) or sepsis rates (1% vs 2%; P = .60).

CONCLUSION

We developed a risk-based protocol for prophylactic antibiotics before prostate biopsy. The protocol was associated with less antibiotic use but did not lead to an increase in infectious complications.

Risk Factors for Delayed-Onset Infection after Mandibular Wisdom Tooth Extractions

Wisdom tooth extraction is one of the most commonly performed procedures by oral maxillofacial surgeons. Delayed-onset infection (DOI) is a rare complication of wisdom tooth extraction, and it occurs ~1–4 weeks after the extraction. In the present study, risk factors for DOI were investigated by retrospectively analyzing the cases of 1400 mandibular wisdom tooth extractions performed at Kagawa University Hospital from April 2015 to June 2022. Inclusion criteria were patients aged >15 years with a wisdom tooth extraction per our procedure. The exclusion criteria were patients with insufficient medical records, a >30-mm lesion around the wisdom tooth shown via X-ray, colonectomy, radiotherapy treatment of the mandible, the lack of panoramic images, and lesions other than a follicular cyst. The DOI incidence was 1.1% (16 cases), and univariate analyses revealed that the development of DOI was significantly associated with the Winter classification (p = 0.003), position (p = 0.003), hypertension (p = 0.011), and hemostatic agent use (p = 0.004). A multivariate logistic regression analysis demonstrated that position (OR = B for A, 7.75; p = 0.0163), hypertension (OR = 7.60, p = 0.013), and hemostatic agent use (OR = 6.87, p = 0.0022) were significantly associated with DOI development. Hypertension, hemostatic use, and position were found to be key factors for DOI; long-term observation may thus be necessary for patients with these risk factors.

Surgical site infections in orthognathic surgery: prolonged versus single-dose antibiotic prophylaxis

The oral cavity is densely populated with microorganisms. As a result, intraoral surgical sites are prone to contamination by pathogens, potentially triggering surgical site infections (SSIs). Prophylactic antibiotics have proven beneficial in reducing the rate of SSIs. However, no consensus has been reached regarding the most effective regimen. The purpose of this study was to investigate two different antibiotic regimens - single-dose and prolonged antibiotic prophylaxis - regarding the rate and severity of postoperative SSIs in patients undergoing orthognathic surgery. Data were analysed retrospectively. Patients who underwent bilateral sagittal split ramus osteotomy or bimaxillary surgery in the study department in 2017 were screened for eligibility. Ninety-nine patients were included in the study and were divided into two groups. The prolonged-antibiotic prophylaxis group (PAP; n = 49) received a 5-day antibiotic prophylaxis regimen, while the single-dose antibiotic prophylaxis group (SDAP; n = 50) received single-dose antibiotic prophylaxis. The groups were assessed for the rate and severity of SSIs following orthognathic surgery. Five patients (10.2%) in the PAP group and seven (14%) in the SDAP group developed infections; no statistically significant difference in the occurrence of SSIs was found (P = 0.380). Single-dose antibiotic prophylaxis is as effective as a 5-day antibiotic prophylaxis regimen in preventing SSIs in orthognathic surgery and is a suitable antibiotic prophylaxis option when considering the risk of antibiotic resistance.

Is Previous Postoperative Infection an Independent Risk Factor for Postoperative Infection after Second Unrelated Abdominal Operation?

BACKGROUND

Infections after abdominal surgery remain a significant problem. Although preoperative antibiotic prophylaxis is a primary strategy used to reduce postoperative infections, it is typically prescribed based on standardized protocols, without attention to previous infection or antibiotic history. Patients with a previous infection after surgery may be at higher risk for infectious complications after subsequent operations owing to antibiotic resistance. We hypothesized that a previous postoperative infection is a significant risk factor for the development of infection after a second unrelated surgery.

STUDY DESIGN

We performed a retrospective study of patients who had undergone 2 unrelated abdominal operations at a tertiary care center from 2012 to 2018. Clinical variables and microbiological culture results were abstracted. Univariate and multivariable regression models were constructed.

RESULTS

Of 758 patients, 15.0% (n = 114) developed an infection after the first operation. After the second operation, 22.8% (n = 26) of those with a previous infection developed another infection, whereas the incidence of an infection after the second operation was only 9.5% (n = 61) in patients who did not develop an infection after the first operation. Multivariable analysis demonstrated that previous infection (odds ratio 2.49, 95% CI 1.46 to 4.25) was associated with future infection risk. Microbiological analysis found that infections after the second surgery were significantly more likely to be antibiotic resistant than infections after the first surgery (82.3% vs 64.1%; p = 0.036). Strikingly, 49% of infections after the second surgery were resistant to the antibiotic prophylaxis given at the time of incision.

CONCLUSIONS

Previous postoperative infection is an independent risk factor for a subsequent postoperative infection and is associated with resistance to standard prophylaxis. Individualization of antibiotic prophylaxis in patients with a previous postoperative infection is warranted.

Effect of antibiotic prophylaxis in dental implant surgery: A multicenter placebo-controlled double-blinded randomized clinical trial

BACKGROUND

The growing resistance of bacteria to antimicrobial medicines is a global issue and a direct threat to human health. Despite this, antibiotic prophylaxis is often still routinely used in dental implant surgery to prevent bacterial infection and early implant failure, despite unclear benefits. There is a lack of sufficient evidence to formulate clear clinical guidelines and therefore there is a need for well-designed, large-scale randomized controlled trials to determine the effect of antibiotic prophylaxis.

PURPOSE

To compare the effect of a presurgical antibiotic regimen with an identical placebo regimen in healthy or relatively healthy patients receiving dental implants.

MATERIALS AND METHODS

The 474 patients participating in the study were recruited from seven clinics in southern Sweden. We randomized the patients into a test and a placebo group; the study was conducted double-blinded. Preoperatively, the test group received 2 g of amoxicillin and the control group, identical placebo tablets. The primary outcome was implant failure; secondary outcomes were postoperative infections and adverse events. Patients were evaluated at two follow-ups: at 7-14 days and at 3-6 months.

RESULTS

Postoperative evaluations of the antibiotic (n = 238) and the placebo (n = 235) groups noted implant failures (antibiotic group: six patients, 2.5% and placebo group: seven patients, 3.0%) and postoperative infections (antibiotic group: two patients, 0.8% and placebo group: five patients, 2.1%). No patient reported any adverse events. Between-group differences in implant failures and postoperative infections were nonsignificant.

CONCLUSION

Antibiotic prophylaxis in conjunction with implant placement is likely of small benefit and should thus be avoided in most cases, especially given the unabated growth in antibiotic-resistant bacteria.

CLINICAL TRIAL REGISTRATION NUMBER

NCT03412305.

Adapted from: Prevention of Viridans Group Streptococcal Infective Endocarditis: A Scientific Statement From the American Heart Association

BACKGROUND

In 2007, the American Heart Association published updated evidence-based guidelines on the recommended use of antibiotic prophylaxis to prevent viridans group streptococcal (VGS) infective endocarditis (IE) in cardiac patients undergoing invasive procedures. The 2007 guidelines significantly scaled back the underlying conditions for which antibiotic prophylaxis was recommended, leaving only 4 categories thought to confer the highest risk of adverse outcome. The purpose of this update is to examine interval evidence of the acceptance and impact of the 2007 recommendations on VGS IE and, if needed, to make revisions based on this evidence.

METHODS AND RESULTS

A writing group was formed consisting of experts in prevention and treatment of infective endocarditis including members of the American Dental Association, the Infectious Diseases Society of America, and the American Academy of Pediatrics, in addition to the American Heart Association. MEDLINE database searches were done for English language articles on compliance with the recommendations in the 2007 guidelines and the frequency of and morbidity or mortality from VGS IE after publication of the 2007 guidelines. Overall, there was good general awareness of the 2007 guidelines but variable compliance with recommendations. There was no convincing evidence that VGS IE frequency, morbidity, or mortality has increased since 2007.

CONCLUSIONS

On the basis of a review of the available evidence, there are no recommended changes to the 2007 VGS IE prevention guidelines. We continue to recommend VGS IE prophylaxis only for categories of patients at highest risk for adverse outcome while emphasizing the critical role of good oral health and regular access to dental care for all. Randomized controlled studies to determine whether antibiotic prophylaxis is effective against VGS IE are needed to further refine recommendations.

Antimicrobial Selection for Transurethral Procedures Across the United States: A State-by-State Antibiogram Evaluation

OBJECTIVE

To evaluate optimal regimens for perioperative antimicrobial prophylaxis in transurethral procedures by examining antimicrobial susceptibility patterns in the United States.

MATERIALS AND METHODS

Through several methods, we attempted to attain an antibiogram for each state. We focused on microbes known to cause infections after transurethral surgeries and antibiotics referred to in current or prior recommendations and compared susceptibility rates across states using Kruskal Walis tests and the Dwass, Steel, Critchlow-Fligner tests. We also examined susceptibility to (non-ceftazidime) third generation cephalosporins.

RESULTS

Data is included from 40 states. For each microbe studied, there was significant variability in sensitivity to antibiotics studied. Current first line recommendations for antimicrobial prophylaxis include first generation cephalosporins with 82%, 80%, and 87% mean coverage for E coli, Proteus, and Klebsiella respectively and trimethoprim-sulfamethoxazole with 74%, 80%, and 93% coverage, respectively. Susceptibility to aminoglycosides is 91%, 92%, and 96%, respectively and to third generation cephalosporin, it is 92%, 99%, and 94%.

CONCLUSION

Current first line recommended antimicrobials for prophylaxis in transurethral procedures provide overall poor predicted coverage based on our database of antibiograms. Alternatives exist that have higher predicted susceptibility, though clinical significance of this and risk of resultant antimicrobial resistance is unknown. Urologists should consider local patterns when selecting antimicrobial prophylaxis for their patients.

Antibiotika im Rahmen der Endokarditisprophylaxe – Risiko und Nutzen

Für die Effektivität und Effizienz einer antibiotischen Prophylaxe vor zahnmedizinischen Eingriffen zum Schutz vor einer infektiösen Endokarditis liegt nur eine geringe Evidenz vor, die keine Rechtfertigung zur generalisierten Therapie von Patienten mit einem erhöhten Endokarditisrisiko darstellt. Aktuelle Leitlinien empfehlen daher, Antibiotika im Rahmen der Endokarditisprophylaxe auf Patienten zu beschränken, die zum einen ein hohes Risiko für die Entstehung einer infektiösen Endokarditis aufweisen und die sich zum anderen zahnärztlichen Eingriffen mit höchstem Endokarditisrisiko unterziehen. Einen hohen Stellwert besitzen allerdings auch Mund- und Hauthygienemaßnahmen, die nicht nur auf Risikopatienten, sondern auch auf die Allgemeinbevölkerung angewendet werden sollten, da die Inzidenz der infektiösen Endokarditis bei Patienten ohne anamnestisch bekannte Herzerkrankung zunehmend ansteigt.

Firmicutes Dysbiosis After Chlorhexidine Prophylaxis in Healthy Patients Submitted to Impacted Lower Third Molar Extraction

Prophylaxis with antiseptic and antibiotic therapy is common in impacted lower third molar surgeries, despite the lack of consensus among professionals and researchers in the indication for healthy patients. The aim of the present preliminary study was to verify the impact of prophylaxis therapy with antiseptic and antibiotic in healthy patients submitted to impacted lower third molar extraction, according to oral microorganism quantification. Eleven patients submitted to impacted lower third molar extraction, under prophylactic therapy with 0.12% chlorhexidine and amoxicillin in four experimental phases, were evaluated. Our results showed no significant reduction in total bacteria load, as well as in Bacteroidetes and C. albicans loads in the oral cavity, after prophylactic therapy with antiseptic and antibiotic. On the other hand, there was a significant difference between the Firmicutes levels across the follow-up, and this effect seems to be large (ηp²=0.94). Post-hoc test demonstrated that the levels of Firmicutes in T1 were higher than T0, T2, and T3, suggesting a microbiota dysbiosis, when 0.12% chlorhexidine use, which may be responsible for selection of antibiotic-resistant microorganisms. Our results alert for an overuse of antiseptic and antibiotics by dentists and for a better evaluation of the available protocols.

Prevention of Viridans Group Streptococcal Infective Endocarditis: A Scientific Statement From the American Heart Association

BACKGROUND

In 2007, the American Heart Association published updated evidence-based guidelines on the recommended use of antibiotic prophylaxis to prevent viridans group streptococcal (VGS) infective endocarditis (IE) in cardiac patients undergoing invasive procedures. The 2007 guidelines significantly scaled back the underlying conditions for which antibiotic prophylaxis was recommended, leaving only 4 categories thought to confer the highest risk of adverse outcome. The purpose of this update is to examine interval evidence of the acceptance and impact of the 2007 recommendations on VGS IE and, if needed, to make revisions based on this evidence.

METHODS AND RESULTS

A writing group was formed consisting of experts in prevention and treatment of infective endocarditis including members of the American Dental Association, the Infectious Diseases Society of America, and the American Academy of Pediatrics, in addition to the American Heart Association. MEDLINE database searches were done for English language articles on compliance with the recommendations in the 2007 guidelines and the frequency of and morbidity or mortality from VGS IE after publication of the 2007 guidelines. Overall, there was good general awareness of the 2007 guidelines but variable compliance with recommendations. There was no convincing evidence that VGS IE frequency, morbidity, or mortality has increased since 2007.

CONCLUSIONS

On the basis of a review of the available evidence, there are no recommended changes to the 2007 VGS IE prevention guidelines. We continue to recommend VGS IE prophylaxis only for categories of patients at highest risk for adverse outcome while emphasizing the critical role of good oral health and regular access to dental care for all. Randomized controlled studies to determine whether antibiotic prophylaxis is effective against VGS IE are needed to further refine recommendations.

Lactobacillus reuteri AN417 cell-free culture supernatant as a novel antibacterial agent targeting oral pathogenic bacteria

Lactobacillus reuteri AN417 is a newly characterized probiotic strain. The activity of AN417 against oral pathogenic bacteria is unknown. We investigated the antibacterial activity of cell-free L. reuteri AN417 culture supernatant (LRS) against three oral pathogens: Porphyromonas gingivalis, Fusobacterium nucleatum, and Streptococcus mutans. P. gingivalis and F. nucleatum have been implicated in periodontal disease, whereas S. mutans causes dental caries. Exposing these oral pathogenic bacteria to LRS significantly reduced their growth rates, intracellular ATP levels, cell viability, and time-to-kill. The minimal inhibitory volume of LRS was 10% (v/v) against P. gingivalis, 20% (v/v) for F. nucleatum, and 30% (v/v) for S. mutans. LRS significantly reduced the integrity of biofilms and significantly suppressed the expression of various genes involved in P. gingivalis biofilm formation. The L. reuteri AN417 genome lacked genes encoding reuterin, reuteran, and reutericyclin, which are major antibacterial compounds produced in L. reuteri strains. LRS treated with lipase and α-amylase displayed decreased antibacterial activity against oral pathogens. These data suggest that the antibacterial substances in LRS are carbohydrates and/or fatty acid metabolites. Our results demonstrate that LRS has antimicrobial activity against dental pathogenic bacteria, highlighting its potential utility for the prevention and treatment of P. gingivalis periodontal disease.

Healthcare Challenges and Future Solutions in Dental Practice: Assessing Oral Antibiotic Resistances by Contemporary Point-Of-Care Approaches

Antibiotic resistance poses a global threat, which is being acknowledged at several levels, including research, clinical implementation, regulation, as well as by the World Health Organization. In the field of oral health, however, the issue of antibiotic resistances, as well as of accurate diagnosis, is underrepresented. Oral diseases in general were ranked third in terms of expenditures among the EU-28 member states in 2015. Yet, the diagnosis and patient management of oral infections, in particular, still depend primarily on empiric means. On the contrary, on the global scale, the field of medical infections has more readily adopted the integration of molecular-based systems in the diagnostic, patient management, and antibiotic stewardship workflows. In this perspective review, we emphasize the clinical significance of supporting in the future antibiotic resistance screening in dental practice with novel integrated and point-of-care operating tools that can greatly support the rapid, accurate, and efficient administration of oral antibiotics.

Educating Patients on Unnecessary Antibiotics: Personalizing Potential Harm Aids Patient Understanding

INTRODUCTION

Antibiotic resistance is a public health emergency fueled by inappropriate antibiotic use. Public education campaigns often focus on global antibiotic resistance or societal harm of antibiotic misuse. There has been little research into what messages have the greatest impact on patient preferences for nonindicated antibiotics in ambulatory clinics.

METHODS

We administered a survey at a primary care clinic in Baltimore, MD. A total of 250 participants rated 18 statements about potential harm from antibiotics on how each statement changed their likelihood to request antibiotics for an upper respiratory tract infection. Statements focused on potential harm either to the individual, to contacts of the individual, to society, and related or not to antibiotic resistance. Initial and final likelihood of requesting antibiotics was measured, and the impact of the statements in each category were compared using general linear models and Wilcoxon rank sum or Kruskal-Wallis tests.

RESULTS

All statements decreased patient likelihood to request antibiotics. Statements about harm to the individual or contacts of the individual decreased participant likelihood to request antibiotics significantly more than statements about societal harm of antibiotic misuse. Statements not discussing antibiotic resistance decreased participant likelihood of requesting antibiotics significantly more than statements discussing antibiotic resistance. Overall likelihood to request antibiotics decreased after the survey by 2.2 points on an 11-point Likert scale (P < .001).

CONCLUSION

When dissuading patients from requesting nonindicated antibiotics, providers and public health campaigns should focus on potential harm of nonindicated antibiotics to the individual rather than societal harm or antibiotic resistance.

Prescribing antibiotics by dentists in Colombia: Toward a conscientious prescription

OBJECTIVES

Inappropriate prescription of antibiotics contributes to antibiotic resistance. Therefore, the objective of this study was to determine the awareness, attitudes, and intention to practice of dentists prescribing antibiotics in Colombia in order to design a virtual learning environment on this subject.

METHODS

In a descriptive study across seven cities, 700 dentists from different Colombian cities were requested to complete a validated questionnaire containing five sections: general information, awareness on antibiotic effectiveness and antibiotic resistance, attitudes regarding prescription decision, intention to practice concerning clinical cases, and complementary information. The level of awareness, attitudes, and intention to practice was determined and Chi-square test was used to determine the existence of significant differences among cities.

RESULTS

The majority of dentists showed a medium level regarding the number of correct answers on awareness (62.4 percent) and attitudes (88.7 percent) and a high level on intention to practice (91.7 percent). Common errors within the awareness section included the meaning of the term "antibiotic resistance" (35 percent) and most dentists were not convinced that such resistance could be derived from prescription of antibiotics (51.2 percent). In the attitudes section, only 45 percent declared that they prescribe antibiotics based mainly on symptoms, and the intention to practice section showed a significant percentage of unnecessary prescription (51 percent for pacemaker users) or absence of prescription (53.9 percent for ventricular septal defect) in antibiotic prophylaxis for infectious endocarditis (IE).

CONCLUSION

The dentists interviewed should be trained and made aware of antibiotic resistance, microbiological and clinical foundations, and current antibiotic prophylaxis guidelines.

Antibiotic prophylaxis in oral and maxillofacial surgery: a systematic review

Surgical site infections are a complication of oral and maxillofacial procedures, with the potential for significant morbidity and mortality. Use of preoperative, perioperative, and postoperative antibiotic prophylaxis to reduce the incidence of surgical site infections must be balanced with considerations of a patients' risk of antibiotic-related adverse events. This review aimed to provide evidence-based recommendations for antibiotic prophylaxis. Searches were conducted using MEDLINE, the Cochrane Library, EMBASE, and PUBMED for maxillofacial procedures including: treatment of dental abscesses, extractions, implants, trauma, temporomandibular joints, orthognathics, malignant and benign tumour removal, and bone grafting, limited to articles published since 2000. A total of 98 out of 280 retrieved papers were included in the final analysis. Systematic reviews were assessed using AMSTAR criteria. Randomised controlled trials were assessed for bias using Cochrane Collaborative tools. The overall quality of evidence was assessed using GRADE. Prophylactic antibiotic use is recommended in surgical extractions of third molars, comminuted mandibular fractures, temporomandibular joint replacements, clean-contaminated tumour removal, and complex implants. Prophylactic antibiotic use is not routinely recommended in fractures of the upper or midface facial thirds. Further research is required to provide recommendations in orthognathic, cleft lip, palate, temporomandibular joint surgery, and maxillofacial surgical procedures in medically-compromised patients.

Resistencia a antibióticos β-lactámicos y eritromicina en bacterias de la cavidad oral

Introducción. La microbiota humana como fuente de bacterias y genes de resistencia constituyen un problema de salud pública. En este estudio se investigó la prevalencia de bacilos entéricos Gram negativos resistentes a β-lactámicos y de los Streptococcus del grupo viridans (EGV) con resistencia a eritromicina en la cavidad oral. Métodos. Se realizó un estudio descriptivo de corte transversal con 193 aislamientos de la cavidad oral sana de 178 adultos que asistieron a una Clínica Odontológica de la ciudad de Cali durante el 2018. La evaluación de la sensibilidad antimicrobiana se realizó en 59 bacilos entéricos y 134 EGV y se identificó por PCR los genes que confieren resistencia a β-lactámicos y eritromicina. El análisis estadístico se realizó mediante el empleo del paquete SPSS vs 23. Resultados. El 84,7% de los bacilos entéricos fueron multirresistentes y presentaron genes bla, siendo blaTEM-1 (49,2%) y blaVIM-2 (30,5%,) los más prevalentes. Los EGV fueron resistentes a eritromicina (38,8%) y clindamicina (28,4%). El 18,7% presentaron el fenotipo cMLSβ, 4,5% el iMLSβ y el 14,9% fueron M.  El gen ermB se detectó en los cMLSβ, (13,4%) y el gen mef  en los M (9,7%). Conclusión. En este estudio se demostró la presencia de EGV y bacilos entéricos resistentes a los antibióticos y portadores de genes de resistencia a eritromicina y genes bla en la cavidad oral sana. La presencia de estas bacterias representa un riesgo para la salud de los individuos portadores y contribuyen a la creciente epidemia de resistencia bacteriana.

Incidence of infective endocarditis caused by viridans group streptococci in Sweden - effect of cessation of antibiotic prophylaxis in dentistry for risk individuals

Introduction

In October 2012, the Swedish Medical Products Agency published new recommendations for the cessation of prophylactic antibiotics in dentistry for the prevention of infective endocarditis (IE). Previously, 2 g of amoxicillin per os would be administered 1 h before invasive dental procedures to patients with valve prosthesis, complicated heart valve disease, and to those with previous endocarditis.

Objectives

The aim of this study was to evaluate whether the total incidence of IE caused by oral viridans group streptococci (VGS) or IE caused by staphylococci, increased in Sweden after the introduction of the new recommendations.

Methods

The incidence of IE in Sweden before and after October 2012 was calculated and compared using an interrupted time series analysis. Separate analyses were conducted for the total incidence of IE, and IE caused by VGS or Staphylococcus aureus. Cases of IE were identified using the Swedish national registry of IE, which has existed since 1995 and contains data from all Swedish hospital clinics specialising in infectious disease. All cases with hospital admission date from the 1^st of Jan 2008, to the 31^st of Dec 2017 were included. The incidence calculations were corrected for annual changes in population size using data from the Swedish government agency Statistics Sweden.

Results

The results show no statistically significant increase in the slope of the trend line of the total incidence of IE, IE caused by VGS or S. aureus in the Swedish general population after October 2012, compared to before.

Conclusion

The results suggest that the recommended cessation of prophylactic antibiotics for the prevention of IE in dentistry has not led to an increased incidence of IE caused by oral streptococci among the Swedish population.

Are Prophylactic Postoperative Antibiotics Necessary after Masculinizing Mastectomy with Free Nipple Graft? A Single-institution Retrospective Review

Antibiotic overuse, particularly in the postoperative period, has contributed substantially to increased rates of antibiotic resistance. Despite insufficient evidence to support prolonged prophylactic antibiotics following the majority of plastic surgery operations, and societal recommendations against the practice, many surgeons continue to perpetuate this cycle. Regarding "newer" operations, wherein minimal data pertaining to antibiotic use have been published, decision-making is often based on historical tradition. As such, continued communication of relevant data is essential to inform best practice guidelines. The aim of this case series was to report postoperative outcomes following chest masculinization with free nipple grafts performed according to a strict antibiotic protocol, which restricted prophylaxis to a single preoperative dose, in the absence of specific risk factors indicating a need for postoperative antibiotics. In this case series featuring 62 consecutive patients undergoing chest reconstruction with 124 free nipple grafts, there were no nipple losses or nipple graft infection events.

Prophylactic antibiotics for staged bone augmentation in implant dentistry

Background: The objective of the study was to assess the effect of prophylactic antibiotics on the outcome of bone augmentation and subsequent dental implant placement by combining the recommended quality assessment methods for systematic reviews and primary studies.Materials and methods: This is a complex systematic review in which systematic reviews as well as primary studies are scrutinised. A search of Medline (OVID), The Cochrane Library (Wiley) and EMBASE, PubMed and Health technology assessment (HTA) organisations as-well as a complementary hand-search was carried out. Selected primary studies were assessed using GRADE. Each study was reviewed by three authors independently.Results: Abstract screening yielded six potential systematic reviews allocated for full-text inspection. A total of ten primary studies were read in full-text. No relevant systematic reviews regarding the topic of this article were found. The quality assessment resulted in two primary studies with a moderate risk of bias. Of the two studies with a moderate risk of bias, one compared a single dose of clindamycin 600 mg preoperatively with the same preoperative dose followed by four doses of 300 mg every 6 h. The second study compared a single dose prophylaxis of two different types of antibiotic compounds.Conclusion: In conclusion, the scientific evidence regarding the use of antibiotic prophylaxis for reducing the risk of infection in conjunction with bone augmentation procedures during dental implant placement is very limited. The infection rate as compared to nonusage of prophylactic antibiotics, selection of the most suitable compound, and the optimal duration of prophylactic treatment is still unknown.

Drug resistance of oral bacteria to new antibacterial dental monomer dimethylaminohexadecyl methacrylate

Only two reports exist on drug-resistance of quaternary ammonium monomers against oral bacteria; both studies tested planktonic bacteria for 10 passages, and neither study tested biofilms or resins. The objectives of this study were to investigate the drug-resistance of Streptococcus mutans, Streptococcus sanguinis and Streptococcus gordonii against dimethylaminohexadecyl methacrylate (DMAHDM), and to evaluate biofilms on resins with repeated exposures for 20 passages for the first time. DMAHDM, dimethylaminododecyl methacrylate (DMADDM) and chlorhexidine (CHX) were tested with planktonic bacteria. Biofilms were grown on a resin containing 3% DMAHDM. Minimum-inhibitory concentrations were measured. To detect drug-resistance, the survived bacteria from the previous passage were used as inoculum for the next passage for repeated exposures. S. gordonii developed drug-resistance against DMADDM and CHX, but not against DMAHDM. Biofilm colony-forming units (CFU) on DMAHDM-resin was reduced by 3–4 log; there was no difference from passages 1 to 20 (p > 0.1). No drug-resistance to DMAHDM was detected for all three bacterial species. In conclusion, this study showed that DMAHDM induced no drug-resistance, and DMAHDM-resin reduced biofilm CFU by 3–4 log, with no significant change from 1 to 20 passages. DMAHDM with potent antibacterial activities and no drug-resistance is promising for dental applications.

Antibiotic prophylaxis in orthognathic surgery: A complex systematic review

Objective

In orthognathic surgery, antibiotics are prescribed to reduce the risk of postoperative infection. However, there is lack of consensus over the appropriate drug, the dose and duration of administration. The aim of this complex systematic review was to assess the effect of antibiotics on postoperative infections in orthognathic surgery.

Methods

Both systematic reviews and primary studies were assessed. Medline (OVID), The Cochrane Library (Wiley) and EMBASE (embase.com), PubMed (non-indexed articles) and Health Technology Assessment (HTA) publications were searched. The primary studies were assessed using GRADE and the systematic reviews by AMSTAR.

Results

Screening of abstracts yielded 6 systematic reviews and 36 primary studies warranting full text scrutiny. In total,14 primary studies were assessed for risk of bias. Assessment of the included systematic reviews identified two studies with a moderate risk of bias, due to inclusion in the meta-analyses of primary studies with a high risk of bias. Quality assessment of the primary studies disclosed one with a moderate risk of bias and one with a low risk. The former compared a single dose of antibiotic with 24 hour prophylaxis using the same antibiotic; the latter compared oral and intravenous administration of antibiotics. Given the limited number of acceptable studies, no statistical analysis was undertaken, as it was unlikely to contribute any relevant information.

Conclusion

With respect to antibiotic prophylaxis in orthognathic surgery, most of the studies to date have been poorly conducted and reported. Thus scientific uncertainty remains as to the preferred antibiotic and the optimal duration of administration.

Surgical Antibiotic Prophylaxis and Risk for Postoperative Antibiotic-Resistant Infections

BACKGROUND

Antibiotic-resistant infections have high rates of morbidity and mortality, and exposure to antibiotics is the crucial risk factor for development of antibiotic resistance. If surgical antibiotic prophylaxis (SAP) increases risk for antibiotic-resistant infections, prophylaxis may cause net harm, even if it decreases overall infection rates.

STUDY DESIGN

This retrospective cohort study included adults who underwent elective surgical procedures and developed infections within 30 postoperative days. Procedures from multiple disciplines were included if SAP was considered discretionary by current guidelines. Postoperative antibiotic-resistant infections were defined as positive culture results from any site within 30 postoperative days, showing intermediate or nonsusceptibility across 1 or more antibiotic classes. Surgical antibiotic prophylaxis included use of antibiotics within any class and at any dose from 1 hour before first incision until the end of the operation.

RESULTS

Among 689 adults with postoperative infections, 338 (49%) had postoperative resistant infections. Use of SAP was not associated with postoperative antibiotic-resistant infections (odds ratio [OR] 0.99; 95% CI 0.67 to 1.46). This result remained robust when the SAP definition was extended to antibiotics given within 4 hours before first incision (OR 0.94; 95% CI 0.63 to 1.40) and when the follow-up window was narrowed to 14 days (OR 0.82; 95% CI 0.50 to 1.34). Previous antibiotic-resistant infections were associated with risk for postoperative antibiotic-resistant infections (OR 1.81; 95% CI 1.16 to 2.83).

CONCLUSIONS

Use of SAP was not associated with risk for postoperative antibiotic-resistant infections in a large cohort of patients with postoperative infections. This provides important reassurance regarding use of surgical antibiotic prophylaxis.