Droplet digital PCR as a tool to detect resistant isolates of Dirofilaria immitis

Prevention of canine heartworm disease, caused by Dirofilaria immitis, relies on macrocyclic lactones for which drug resistance is now a concern. Although genetic polymorphisms have been associated with resistance in D. immitis populations, the mechanism is still not well understood. The lack of reliable in vitro assays to detect resistance is a limitation for confirming resistance. Ten single nucleotide polymorphisms (SNPs) were previously clinically validated in D. immitis resistant isolates, using the MiSeq platform. This technique although useful for research studies is expensive and does not facilitate rapid detection of these markers in small numbers of clinical samples. We developed a droplet digital PCR protocol for detecting SNPs correlating with ML resistance. Specific primers and hydrolysis probes encompassing the wildtype and mutant alleles were designed to amplify the SNP targets from genomic DNA of different D. immitis isolates. Allele frequencies were determined and the suitability of the ddPCR assay was assessed and compared with MiSeq data. The ddPCR assay accurately detected and quantified alternate nucleotides in two isolates of reference, the ML-susceptible Missouri (MO) and ML-resistant JYD-34, at the previously identified SNP positions. The presence of the SNPs was also determined in additional isolates with known or putative susceptible or resistant phenotypes. We observed SNP1 and SNP2 are more predictive markers and appear suitable for rapid detection and monitoring of drug resistance. Our results suggested that ddPCR could be employed to distinguish infection due to actual genetic resistance from infection with susceptible parasites and also for rapid detection of isolates not only with ML susceptible and resistant genotypes but also mixed genotypes that correspond to heterogeneous isolates containing a mixed population of ML susceptible and resistant parasites. DdPCR may be a useful tool for conducting surveys, or assessments of individual isolates, for genetic evidence of resistance or developing resistance.

Translation and perceptions of the French version of the Cancer Survivor Profile-Breast Cancer (CSPro-BC): a tool to identify and manage unmet needs

PURPOSE

Worldwide healthcare systems continue to struggle to reduce the unmet needs of a growing population of breast cancer survivors (BCSs). The Cancer Survivor Profile-Breast Cancer (CSPro-BC) survey was developed to address BCS's specific needs. This study aims to produce a culturally adapted French version of the CSPro-BC.

METHODS

The CSPro-BC_(French) was developed through five steps including back translation, use of a multidisciplinary committee, and pretest with BCS (n = 22). Healthcare providers (HCP) (n = 7) from cancer and primary care settings were also interviewed to obtain perceptions of facilitators and barriers to utilization in daily practice.

RESULTS

BCS were 40-69 years old (50%), ≥ 5 years post-diagnosis (45%), received chemotherapy alone or in combination (73%). Questionnaire instructions were perceived as clear, the number of questions (n = 73) acceptable, the questions non-intrusive and not complicated. Clarity of questions (min = 1; max = 7) ranged from 4 to 7 with a mean score of 5.9 out of 7. HCP perceived the CSPro-BC_(French) as useful for improving communication with BCS. However, HCP stressed implementation concerns regarding competencies, BCS acceptability, and limited resources in the healthcare system to meet the identified concerns.

CONCLUSIONS

CSPro-BC_(French) is a credible tool for assessment in Francophone nations. Our study provides an important perspective in the translation method, including both survivors and HCP perspectives. Further research is required to evaluate its psychometric qualities, sensitivity to change and its clinical signification.

IMPLICATIONS FOR CANCER SURVIVORS

Access to assessment tools specific to French-speaking cancer survivors having a potential to improve support from HCP and self-management capacity for BCS.