Effect of 0.4% stannous fluoride gel on Streptococci mutans in relation to elastomeric rings and steel ligatures in orthodontic patients.

BACKGROUND: Patients with fixed orthodontic appliances often experience an absolute increase in the number of Streptococci mutans colony-forming units (cfu). The aim of this investigation was to study the development of biofilm and S. mutans cfu in connection with stainless steel ligatures and elastomeric rings in orthodontic patients treated with and without 0.4% stannous fluoride gel (SFG). MATERIAL: Forty-seven patients were divided into 2 groups: those treated with 0.4% SFG for 4 minutes (experimental) and those without 0.4% SFG (control). In each patient, elastomeric rings were used for ligation on 1 side of the dental arch midline, and stainless steel ligatures were used on the opposite side. Saliva samples were collected before and after appliance placement. At 15 and 30 days after appliance placement, biofilm samples from the stainless steel ligatures and the elastomeric rings were collected and subjected to microbiologic procedures and scanning electron microscopy (SEM) analysis. RESULTS: The numbers of S. mutans cfu in the saliva and biofilm were not statistically different between the teeth fitted with elastomeric rings and stainless steel ligatures, or between the experimental and control groups. SEM analysis showed biofilm formation on both ligature ties. CONCLUSIONS: Topical application of 0.4% SFG in orthodontic patients with elastomeric rings or stainless steel ligatures does not cause a significant decrease in S. mutans cfu in the saliva and biofilm.     

Tracheal Aspirate as an Alternative Biologic Sample for Pharmacogenomics Testing in Mechanically Ventilated Pediatric Patients

Patients in the pediatric intensive care unit are exposed to multiple medications and are at high risk for adverse drug reactions. Pharmacogenomic (PGx) testing could help decrease their risk of adverse reactions. Although whole blood is preferred for PGx testing, blood volume in this population is often limited. However, for patients on mechanical ventilation, tracheal secretions are abundant, frequently suctioned, and discarded. Thus, the aim of this pilot study was to determine if tracheal aspirates could be used as a source of human genomic DNA for PGx testing. We successfully extracted DNA from tracheal secretions of all 23 patients in the study. The samples were successfully genotyped for 10 clinically actionable single nucleotide variants across 3 cytochrome P450 genes (CYP2D6, CYP2C19, and CYP3A5). Using DNA from whole blood samples in 11 of the patients, we confirmed the accuracy of the genotyping with 100% concordance. Therefore, our results support the use of tracheal aspirates from mechanically ventilated children as an adequate biospecimen for clinical genetic testing.

Children admitted to the pediatric intensive care unit (PICU) receive an average of 10 different medications per day and receive an average cumulative 20 medications during their stay. ¹ Many of these have clinical guidelines for using pharmacogenomic (PGx) testing to guide the drug choice and/or dose, including voriconazole, selective serotonin reuptake inhibitors, tricyclic antidepressants, and codeine. ² , ³ , ⁴ , ⁵ The US Food and Drug Administration (FDA) has placed genetic testing recommendations and black box warnings on over 100 drug labels, including guidelines on gene‐drug pairs. The Clinical Pharmacogenetics Implementation Consortium (CPIC) has published guidelines for 35 medications with plans for writing over 100 more. ⁶ These initiatives are indicative of the importance of PGx to prescribing practices. The use of PGx has not been routinely utilized in the PICU, but as more evidence and guidelines for PGx‐guided dosing emerges, this could play an important role in the safe delivery of medications to patients in the PICU.The preferred biospecimen for PGx testing is whole blood but saliva and buccal swabs have also been validated and used as an alternative source of DNA. ⁷ , ⁸ , ⁹ , ¹⁰ , ¹¹ However, in small patients, blood volumes can be limited and mechanical ventilation or sedation can impair the collection of saliva or buccal swabs. In pediatrics, most current blood sampling guidelines are not evidence based; so, it is generally recommended to use alternatives to blood to ensure patient safety and maximize clinical benefit. ¹² , ¹³ In addition, blood samples cannot be used for genotyping from children that have had stem cell transplants or recent blood transfusions. Therefore, there is a need to identify an alternative source of DNA that can be used for validating biomarkers in clinical trials and conducting clinical PGx testing.Many patients admitted to the PICU are mechanically ventilated. When they are vented, the patient’s respiratory secretions are frequently suctioned and discarded. As this biological sample is plentiful, easily accessible, and collection is noninvasive, we hypothesized that tracheal aspirates from mechanically ventilated patients could be used as a source of DNA for clinical genotyping. Although one might assume that this would work, there could be too little DNA or it could be to degraded to use for genotyping; so, the feasibility needs to be supported by laboratory data. Thus, the aim of this study was to determine if tracheal aspirates from mechanically ventilated pediatric patients can be used as a source of DNA for PGx testing.