Molecular evidence of widespread benzimidazole drug resistance in Ancylostoma caninum from domestic dogs throughout the USA and discovery of a novel ß-tubulin benzimidazole resistance mutation.

Ancylostoma caninum is an important zoonotic gastrointestinal nematode of dogs worldwide and a close relative of human hookworms. We recently reported that racing greyhound dogs in the USA are infected with A. caninum that are commonly resistant to multiple anthelmintics. Benzimidazole resistance in A. caninum in greyhounds was associated with a high frequency of the canonical F167Y(TTC>TAC) isotype-1 ß-tubulin mutation. In this work, we show that benzimidazole resistance is remarkably widespread in A. caninum from domestic dogs across the USA. First, we identified and showed the functional significance of a novel benzimidazole isotype-1 ß-tubulin resistance mutation, Q134H(CAA>CAT). Several benzimidazole resistant A. caninum isolates from greyhounds with a low frequency of the F167Y(TTC>TAC) mutation had a high frequency of a Q134H(CAA>CAT) mutation not previously reported from any eukaryotic pathogen in the field. Structural modeling predicted that the Q134 residue is directly involved in benzimidazole drug binding and that the 134H substitution would significantly reduce binding affinity. Introduction of the Q134H substitution into the C. elegans ß-tubulin gene ben-1, by CRISPR-Cas9 editing, conferred similar levels of resistance as a ben-1 null allele. Deep amplicon sequencing on A. caninum eggs from 685 hookworm positive pet dog fecal samples revealed that both mutations were widespread across the USA, with prevalences of 49.7% (overall mean frequency 54.0%) and 31.1% (overall mean frequency 16.4%) for F167Y(TTC>TAC) and Q134H(CAA>CAT), respectively. Canonical codon 198 and 200 benzimidazole resistance mutations were absent. The F167Y(TTC>TAC) mutation had a significantly higher prevalence and frequency in Western USA than in other regions, which we hypothesize is due to differences in refugia. This work has important implications for companion animal parasite control and the potential emergence of drug resistance in human hookworms.

Variation in DNA Methylation in Avian Nestlings Is Largely Determined by Genetic Effects.

As environmental fluctuations are becoming more common, organisms need to rapidly adapt to anthropogenic, climatic, and ecological changes. Epigenetic modifications and DNA methylation in particular provide organisms with a mechanism to shape their phenotypic responses during development. Studies suggest that environmentally induced DNA methylation might allow for adaptive phenotypic plasticity that could last throughout an organism's lifetime. Despite a number of studies demonstrating environmentally induced DNA methylation changes, we know relatively little about what proportion of the epigenome is affected by environmental factors, rather than being a consequence of genetic variation. In the current study, we use a partial cross-foster design in a natural great tit (Parus major) population to disentangle the effects of common origin from common rearing environment on DNA methylation. We found that variance in DNA methylation in 8,315 CpG sites was explained by a common origin and only in 101 by a common rearing environment. Subsequently, we mapped quantitative trait loci for the brood of origin CpG sites and detected 754 cis and 4,202 trans methylation quantitative trait loci, involving 24% of the CpG sites. Our results indicate that the scope for environmentally induced methylation marks independent of the genotype is limited and that the majority of variation in DNA methylation early in life is determined by genetic factors instead. These findings suggest that there may be little opportunity for selection to act on variation in DNA methylation. This implies that most DNA methylation variation likely does not evolve independently of genomic changes.

Teledermatology Platforms Usage and Barriers: A Cross-Sectional Analysis of United States-Based Dermatologists Pre- and Post-COVID-19.

BACKGROUND: During the global COVID-19 pandemic, dermatologists increasingly adopted teledermatology to facilitate patient care. OBJECTIVE: To identify differences in teledermatology platform usage and functionality among dermatologists as a means of understanding the potential effect on virtual healthcare access. METHODS: Results from a 2021 cross-sectional pre-validated survey distributed to actively practicing United States dermatologists were analyzed based on timepoint when teledermatology was adopted relative to COVID-19, previous/currently used platforms, self-reported platform functionality, and barriers to teledermatology implementation. Analysis was performed using chi-square and odds ratios (OR) with 95% confidence intervals (95% CI) for categorical data and single-factor analysis of variance (ANOVA) with post-hoc Tukey-Kramer for continuous data. P<.05 was considered significant. RESULTS: Early adopters (EAs) trialed significantly more (2.3 vs 1.9, P=0.02) platforms than (post) COVID adopters (CAs) before choosing their current platform. More EAs reported using platforms capable of uploading images (P=.002), required a mobile application (P=.006), and allowed staff to join patient encounters (P<.001). While poor image quality was the most cited barrier to implementation, CAs and non-adaptors (NAs) were materially more likely to cite it as their largest barrier to teledermatology. LIMITATIONS: The retrospective nature of the study and potential response bias. CONCLUSION: Dermatologists' use of teledermatology materially correlates with their teledermatology-adoption timepoint, and future usage may be materially impacted by the end of the COVID-19 public health emergency. Future studies should aim at how implementation and barriers to teledermatology usage may impact access to care. J Drugs Dermatol. 2024;23(2): doi:10.36849/JDD.7819e.

Use and perceptions of Cannabidiol among individuals in treatment for opioid use disorder.

BACKGROUND: Cannabidiol (CBD) is a widely available cannabis product with many claims as to potential health benefits including alleviating symptoms related to opioid use disorder (OUD). However, little is known as to how individuals with OUD perceive CBD, to what extent they may already be using CBD, and for what purposes. METHODS: A survey was conducted among individuals receiving treatment for OUD at the Addiction Institute of Mount Sinai in New York City from July 2021 to August 2023. The survey consisted of demographic questions, questions about opioid use, CBD use, and perceptions regarding CBD. Statistical analysis using ordinal logistic regression was employed to compare perceptions between CBD users and non-users while adjusting for age and race. RESULTS: Among 587 respondents, 550 completed the survey. Among all survey completers, 129 (23%) reported a history of using CBD for a variety of reasons including: anxiety (81, 62.8%), pain (65, 50.4%), sleep (63, 48.8%), depression (62, 48.1%), recreational purposes (32, 24.8%), or for other reasons (8, 6.2%). Of note, 22 (17.1%) respondents reported using CBD to control their addiction and 54 (41.9%) reported using CBD to ease opioid withdrawal symptoms. CBD users demonstrated more positive perceptions regarding its legality (ß = 0.673, OR = 1.960, 95% CI [1.211, 3.176], p = .006), social acceptance (ß = 0.718, OR = 2.051, 95% CI [1.257, 3.341], p = .004), and therapeutic potential compared to non-users. CBD users also had a more positive view of its potential future role in managing addiction (ß = 0.613, OR = 1.846, 95% CI [1.181, 2.887], p = .007). CONCLUSIONS: This study highlights a significant association between CBD usage and progressive views regarding CBD among individuals with OUD, suggesting a growing interest in CBD as a potential adjunctive therapy for individuals in substance use treatment. Some patients are already using CBD for anxiety, pain, sleep, depression, or as a harm reduction intervention to control their addiction or for opioid withdrawal symptoms. These findings underscore the importance of integrating patient perspectives into future research and treatment strategies involving CBD in the context of OUD.

Terminology of e-Oral Health: Consensus Report of the IADR's e-Oral Health Network Terminology Task Force.

OBJECTIVE: Authors reported multiple definitions of e-oral health and related terms, and used several definitions interchangeably, like mhealth, teledentistry, teleoral medicine and telehealth. The International Association of Dental Research e-Oral Health Network (e-OHN) aimed to establish a consensus on terminology related to digital technologies used in oral healthcare. METHOD: The Crowdsourcing Delphi method used in this study comprised of four main stages. In the first stage, the task force created a list of terms and definitions around digital health technologies based on the literature and established a panel of experts. Inclusion criteria for the panellists were: to be actively involved in either research and/or working in e-oral health fields; and willing to participate in the consensus process. In the second stage, an email-based consultation was organized with the panel of experts to confirm an initial set of terms. In the third stage, consisted of: a) an online meeting where the list of terms was presented and refined; and b) a presentation at the 2022-IADR annual meeting. The fourth stage consisted of two rounds of feedback to solicit experts' opinion about the terminology and group discussion to reach consensus. A Delphi-questionnaire was sent online to all experts to independently assess a) the appropriateness of the terms, and b) the accompanying definitions, and vote on whether they agreed with them. In a second round, each expert received an individualised questionnaire, which presented the expert's own responses from the first round and the panellists' overall response (% agreement/disagreement) to each term. It was decided that 70% or higher agreement among experts on the terms and definitions would represent consensus. RESULTS: The study led to the identification of an initial set of 43 terms. The list of initial terms was refined to a core set of 37 terms. Initially, 34 experts took part in the consensus process about terms and definitions. From them, 27 experts completed the first rounds of consultations, and 15 the final round of consultations. All terms and definitions were confirmed via online voting (i.e., achieving above the agreed 70% threshold), which indicate their agreed recommendation for use in e-oral health research, dental public health, and clinical practice. CONCLUSION: This is the first study in oral health organised to achieve consensus in e-oral health terminology. This terminology is presented as a resource for interested parties. These terms were also conceptualised to suit with the new healthcare ecosystem and the place of e-oral health within it. The universal use of this terminology to label interventions in future research will increase the homogeneity of future studies including systematic reviews.

Tea film formation in artificial tap water.

On the surface of tea infusions, the formation of a transparent, shiny film which cracks upon disturbance can often be observed. This study aims to determine how water composition, tea varieties, and tea additives impact the formation and properties of tea film, often also called tea scum. The strength of the surface film, composed of polyphenols complexed with various ions from tap water, was investigated by interfacial rheology. Microscopy and ellipsometry were used to investigate structure and thickness of the adsorption layer, respectively. We find that green tea forms more visible layers than black tea in soft and moderate artificial tap water, but in these same waters, black tea demonstrated greater surface strength. In hard artificial tap water, green tea demonstrated greater surface strength than black. No visible layer nor surface strengthening was observed on rooibos tea. Brews in hard artificial tap water formed brittle films for green tea, fracturing at strains one order of magnitude lower than in soft or moderate. Despite large variations in film strength, black tea at all water hardness levels tested formed a film with 20 nm thickness. In black tea an increased resilience to deformation was found when adding ß-casein, a protein found in milk.

Assessment of visual field progression in glaucoma.

PURPOSE OF REVIEW: Perimetry plays an important role in the diagnosis and management of glaucoma. This article discusses the assessment of visual field progression in patients with glaucoma. RECENT FINDINGS: Selecting the best visual field test strategy and establishing a baseline of visual fields will assist clinicians in the detection of glaucomatous progression. Repeat testing serves to confirm or refute changes on visual field testing. More frequent testing after initial diagnosis is recommended to establish a baseline and to identify patients with rapid progression who may need more aggressive management. Statistically significant changes on event analysis can prompt examination of a patient's trend analysis to determine whether clinically significant deterioration may be occurring. Future applications of machine learning can complement existing methods of visual field interpretation. SUMMARY: Many treated patients with glaucoma will experience visual field progression. Optimal utilization of visual field testing strategy and analytical software can help clinicians identify patients with glaucomatous progression likely to cause functional visual disability.

Life satisfaction and peace of mind among dentists: a cross-sectional study.

OBJECTIVES: This study sought to identify the factors associated with the life satisfaction and peace of mind (PoM) of dentists not in full-time clinical training. MATERIALS AND METHODS: Cross-sectional questionnaires were distributed to dentists in Taiwan to collect their life satisfaction, PoM, sociodemographic data, and dental career-related characteristics. Life satisfaction was measured using a 5-item Satisfaction with Life Scale. PoM was measured using a 7-item Peace of Mind Scale. Descriptive statistics and multiple linear regression models were estimated to explore potential associations between the two scales and the examined factors. RESULTS: A total of 1196 dentists (45.6% female; mean age = 44.12) completed the questionnaires. The response rate of completed questionnaires from email invitations was 32.9%. On multivariable analysis, life satisfaction and PoM were associated with age (b = 0.008 in both), better perceived health (b = 0.262 and 0.308, respectively), family interaction (b = 0.264 and 0.207, respectively), and friend relationships (b = 0.076 and 0.091, respectively). Being married (b = 0.191), being specialized (b = 0.127), working in private practice, and spending 10 to 39 h per week with patients (b = 0.101 to 0.162) were associated with a higher level of life satisfaction but not PoM. CONCLUSIONS: Specialists working in private practice without working overtime were associated with better life satisfaction. However, the dentists' health and relationships with family were more related to their subjective well-being than their professional achievements. CLINICAL RELEVANCE: Our findings can help policymakers increase awareness of the well-being of general dentists and those in academia or hospitals to promote their mental health.

A database for ITS2 sequences from nematodes.

BACKGROUND: Marker gene surveys have a wide variety of applications in species identification, population genetics, and molecular epidemiology. As these methods expand to new types of organisms and additional markers beyond 16S and 18S rRNA genes, comprehensive databases are a critical requirement for proper analysis of these data. RESULTS: Here we present an ITS2 rDNA database for marker gene surveys of both free-living and parasitic nematode populations and the software used to build the database. This is currently the most complete and up-to-date ITS2 database for nematodes and is able to reproduce previous analysis that used a smaller database. CONCLUSIONS: This database is an important resource for researchers working on nematodes and also provides a tool to create ITS2 databases for any given taxonomy.

Life satisfaction of Taiwanese dental graduates received residencies in the U.S.: a cross-sectional study.

BACKGROUND: Each year, more than 200 international dental graduates start U.S. specialty trainings to become specialists. It is unknown if their life satisfaction is associated with any dental career-related factor before residencies (e.g. dental school class rank, research experience, or private practice experience) and after residencies (e.g. staying in the U.S., teaching status, workplace, or board certification). This cross-sectional study aimed to identify these potential factors by surveying Taiwanese dental graduates who pursued U.S. residencies. METHODS: Life satisfaction was measured with a structured questionnaire, Satisfaction With Life Scale (SWLS), which includes five statements on a 5-point Likert scale. Online surveys were sent out to 290 Taiwanese dental graduates who were known to pursue U.S. residencies. T-test, one way analysis of variance, and multivariable adjusted generalized linear model (GLM) were used to assess the differences of mean SWLS scores from different variables. RESULTS: Surveys were completed by 158 dentists. Mean SWLS score of 125 specialists was higher (p = 0.0007) than the score of 33 residents. For the 125 specialists, multivariable adjusted GLM demonstrated better life satisfaction was positively associated with multiple independent factors, such as having research experience, being ranked in the top 26 ~ 50% of the class in dental school, starting U.S. residency within 4 years after dental school, starting residency before year 1996, and specializing in endodontics (vs. periodontics). Life satisfaction was not associated with any factors after residency (e.g. staying in the U.S. afterwards, teaching status, or workplace), but better mean life satisfaction score was significantly associated with being American specialty board certified (p < 0.001) for the specialists in the 26 ~ 75% of their class in dental school. For the 33 residents, better mean life satisfaction score was associated with better dental school class rank in both bivariate (p = 0.020) and multivariable adjusted GLM (p = 0.004) analyses. CONCLUSIONS: The life satisfaction of Taiwanese dental graduates pursuing U.S. residencies might be associated with some professional factors, such as research experience, dental school class rank, residency timing, specialty type, and specialty board certification. We hope our results may provide some objective information on making career decisions for international dental graduates/students who are preparing for U.S. residency.

An evaluation of health workforce models addressing oral health in residential aged care facilities: A systematic review of the literature.

BACKGROUND: In Australia and globally, there is an increasing problem of unmet oral health needs of older people above 65 residing in aged care facilities. Various workforce models have been trialled to implement oral health care programmes in aged care facilities, but the evidence behind these programmes and their underlying workforce models is not known. OBJECTIVE: To systematically review the literature on the effectiveness, and economic feasibility of the current workforce models addressing oral care in aged care facilities. METHODS: CINAHL, Cochrane CENTRAL, MEDLINE, EMBASE, EMB Reviews, NHS Economic Evaluation Database and grey literature were searched. Studies were included if they described an oral health workforce model with a clinical intervention and defined oral health outcome measures. Analysis was conducted using the NHMRC guidelines for scientific and economic evaluations. RESULTS: Twenty-eight studies were included. Four distinct workforce models of care were identified. 60% of the studies demonstrated short-term effectiveness in clinical measures. Workforce models were similar in their effectiveness, with varying levels of quality within each model. Although three studies considered individual components of economic feasibility, only one provided a comprehensive economic analysis of both the costs and health outcomes. CONCLUSIONS IMPLICATIONS OF FINDINGS: All workforce models of care had some positive impact on oral health for residents of aged care. Oral health should be included as a health focus in age care facilities. Future studies should include longer-term health outcomes with rigorous economic analysis to ensure sustainably delivered workforce models of care for oral health management within aged care.

Dynamics of sleep spindles and coupling to slow oscillations following motor learning in adult mice.

Sleep spindles have been implicated in motor learning in human subjects, but their occurrence, timing in relation to cortical slow oscillations, and relationship to offline gains in motor learning have not been examined in animal models. In this study, we recorded EEG over bilateral primary motor cortex in conjunction with EMG for 24 h following a period of either baseline handling or following rotarod motor learning to monitor sleep. We measured several biophysical properties of sleep spindles and their temporal coupling with cortical slow oscillations (SO, <1 Hz) and cortical delta waves (1-4 Hz). Following motor learning, we found an increase in spindles during an early period of NREM sleep (1-4 h) without changes to biophysical properties such as spindle power, peak frequency and coherence. In this same period of early NREM sleep, both SO and delta power increased after motor learning. Notably, a vast majority of spindles were associated with minimal SO power, but in the subset that were associated with significant SO power (>1 z-score above the population mean), spindle-associated SO power was greater in spindles following motor learning compared to baseline sleep. Also, we did not observe a group-level preferred phase in spindle-SO or spindle-delta coupling. While SO power alone was not predictive of motor performance in early NREM sleep, both spindle density and the difference in the magnitude of the mean resultant vector length of the phase angle for SO-associated spindles, a measure of its coupling precision, were positively correlated with offline change in motor performance. These findings support a role for sleep spindles and their coupling to slow oscillations in motor learning and establish a model in which spindle timing and the brain circuits that support offline plasticity can be mechanistically explored.

The International Caries Detection and Assessment System Is a Visual Diagnostic System That Is Highly Reproducible and Accurate for Coronal Carious Lesions Detection but Only Moderately Reproducible and Accurate for Assessing Lesion Progression.

ARTICLE TITLE AND BIBLIOGRAPHIC INFORMATION: The International Caries Detection and Assessment System-ICDAS: A Systematic Review. Ekstrand KR, Gimenez T, Ferreira FR, Mendes FM, Braga MM. Caries Res 2018; 52:406-419. SOURCE OF FUNDING: Government FAPESP, the Sao Paulo Research Foundation (FAPESP 2012/17888-1 and 2014/00271-7) and the Brazilian National Council for Scientific and Technological Development (CNPq) (400736/2014-4) TYPE OF STUDY/DESIGN: Systematic review with meta-analysis of data.

Attenuation of the progression of articular cartilage degeneration by inhibition of TGF-ß1 signaling in a mouse model of osteoarthritis.

Transforming growth factor beta 1 (TGF-ß1) is implicated in osteoarthritis. We therefore studied the role of TGF-ß1 signaling in the development of osteoarthritis in a developmental stage-dependent manner. Three different mouse models were investigated. First, the Tgf-ß receptor II (Tgfbr2) was specifically removed from the mature cartilage of joints. Tgfbr2-deficient mice were grown to 12 months of age and were then euthanized for collection of knee and temporomandibular joints. Second, Tgfbr2-deficient mice were subjected to destabilization of the medial meniscus (DMM) surgery. Knee joints were then collected from the mice at 8 and 16 weeks after the surgery. Third, wild-type mice were subjected to DMM at the age of 8 weeks. Immediately after the surgery, these mice were treated with the Tgfbr2 inhibitor losartan for 8 weeks and then euthanized for collection of knee joints. All joints were characterized for evidences of articular cartilage degeneration. Initiation or acceleration of articular cartilage degeneration was not observed by the genetic inactivation of Tgfbr2 in the joints at the age of 12 months. In fact, the removal of Tgfbr2 and treatment with losartan both delayed the progression of articular cartilage degeneration induced by DMM compared with control littermates. Therefore, we conclude that inhibition of Tgf-ß1 signaling protects adult knee joints in mice against the development of osteoarthritis.

Oral Contraceptive Use and Prevalence of Self-Reported Glaucoma or Ocular Hypertension in the United States.

PURPOSE: To investigate the association between oral contraceptive (OC) use and glaucoma prevalence in the United States. DESIGN: Cross-sectional study. PARTICIPANTS: A total of 3406 female participants, aged 40 years or older, from the 2005 to 2008 National Health and Nutrition Examination Survey, who reported a presence or absence of glaucoma or ocular hypertension completed both the vision and the reproductive health questionnaires and underwent eye examinations. METHODS: Multivariate regression analysis was used to assess the correlation between OC use and self-reported glaucoma or ocular hypertension (n = 231 cases), controlling for potential confounders, including age, ethnicity, systemic comorbidities such as hypertension and stroke, ocular diseases such as cataract and diabetic retinopathy, and reproductive health factors, including age at menopause, age at menarche, history of hormone replacement therapy, and gynecological surgical history. MAIN OUTCOME MEASURES: The outcome variable was self-reported glaucoma or ocular hypertension. RESULTS: After adjusting for confounders, those with ≥3 years of OC use had greater odds (odds ratio, 1.94; 95% confidence interval, 1.22-3.07) of self-reported glaucoma or ocular hypertension. Other factors associated with higher glaucoma or ocular hypertension prevalence included older age, African American race, and later age at menarche. CONCLUSIONS: Oral contraceptive use may be associated with increased risk of self-reported glaucoma or ocular hypertension.

Myopia and glaucoma: sorting out the difference.

PURPOSE OF REVIEW: The aim of the present review was to summarize the evidence implicating the association between myopia and glaucoma, the possible underlying mechanisms for this relation, and the controversies surrounding detection of glaucomatous changes in coexisting myopia. RECENT FINDINGS: Numerous studies have shown that increasing categories of myopia are associated with a higher risk for optic neuropathy and glaucoma-like visual field defects. Recently, some high-resolution imaging modalities have been developed that aid further detection of the microanatomical changes of the optic nerve head and thus may provide a new insight to explain the association between myopia and glaucoma. Although the highly myopic eye usually shows many structural and functional defects that are difficult to distinguish from those caused by glaucoma, some new methods have been introduced to better differentiate between these changes. SUMMARY: The interaction of myopia with glaucoma risk remains complex, largely because of the retinal and nerve fiber layer damage that occurs in myopia alone. Whether to treat for glaucoma relies on the suspicion level of the clinician who must consider other risk factors for vision loss. Ultimately, it is the progression of glaucoma-like findings that determines whether a myopic patient has glaucoma.

Addressing Moral Distress After Dobbs v. Jackson Women's Health Organization : A Professional Virtues-Based Approach.

ABSTRACT: The June 2022 U.S. Supreme Court decision in Dobbs v. Jackson Women's Health Organization abolished federal protections for reproductive choice. In states where subsequent legislation has restricted or banned access to abortion services, physicians and trainees are prevented from providing ethically justified evidence-based care when patients with previable pregnancies are seeking an abortion. Pregnant patients' vulnerabilities, stress, and the undue burden that they experience when prevented from acting in accordance with their reproductive decision-making can evoke negative emotional consequences, including moral distress in clinicians. Moral distress occurs when clinicians feel a moral compulsion to act a certain way but cannot do so because of external constraints, including being hindered by state laws that curtail practicing in line with professional standards on reproductive health care. Moral distress has the potential to subvert prudent clinical judgment. The authors provide recommendations for managing moral distress in these circumstances based on the professional virtues. The fundamental professional virtues of integrity, compassion, self-effacement, self-sacrifice, and humility inform the management of moral distress and how to respond thoughtfully and compassionately, without over-identification or indifference to the plight of patients denied abortions. The authors also discuss the role of academic leaders and medical educators in cultivating a virtue-based professional culture at the forefront of clinical and educational processes in a post- Dobbs world.

A set of nematode rRNA cistron databases and a primer assessment tool to enable more flexible and comprehensive metabarcoding.

The ITS-2-rRNA has been particularly useful for nematode metabarcoding but does not resolve all phylogenetic relationships, and reference sequences are not available for many nematode species. This is a particular issue when metabarcoding complex communities such as wildlife parasites or terrestrial and aquatic free-living nematode communities. We have used markerDB to produce four databases of distinct regions of the rRNA cistron: the 18S rRNA gene, the 28S rRNA gene, the ITS-1 intergenic spacer and the region spanning ITS-1_5.8S_ITS-2. These databases comprise 2645, 254, 13,461 and 10,107 unique full-length sequences representing 1391, 204, 1837 and 1322 nematode species, respectively. The comparative analysis illustrates the complementary value but also reveals a better representation of Clade III, IV and V than Clade I and Clade II nematodes in each case. Although the ITS-1 database includes the largest number of unique full-length sequences, the 18S rRNA database provides the widest taxonomic coverage. We also developed PrimerTC, a tool to assess primer sequence conservation across any reference sequence database, and have applied it to evaluate a large number of previously published rRNA cistron primers. We identified sets of primers that currently provide the broadest taxonomic coverage for each rRNA marker across the nematode phylum. These new resources will facilitate more comprehensive metabarcoding of nematode communities using either short-read or long-read sequencing platforms. Further, PrimerTC is available as a simple WebApp to guide or assess PCR primer design for any genetic marker and/or taxonomic group beyond the nematode phylum.