Point-of-care molecular diagnostics for the detection of group A Streptococcus in non-invasive skin and soft tissue infections: a validation study.

BACKGROUND: Skin and soft tissue infections (SSTIs) are commonly caused by group A Streptococcus (GAS). Rapid molecular assays for detecting GAS in wounds would help with clinical management. This study assessed a point-of-care system for the detection of GAS in non-severe SSTIs in a Native American community in the Southwest. METHODS: Patients presenting with a new non-severe SSTI were eligible if a swab was collected. The swab was tested by traditional culture methods and using the cobas® Liat® point-of-care (POC) system and results were compared. RESULTS: 399 samples were included. The final result from the POC assay was positive for 52.0% of samples. Compared to culture, the POC assay had a sensitivity of 100% and specificity of 99.5%. CONCLUSIONS: The cobas® Liat® system accurately and efficiently identified GAS in non-severe SSTIs. Having a POC test available to rapidly identify or rule out GAS could help to minimize overuse of antibiotics.

Potential implications of six American Indian patients with myopathy, statin exposure and anti-HMGCR antibodies.

OBJECTIVES: Statin-associated autoimmune myopathy is a rare condition associated with the formation of autoantibodies to 3-hydroxy-3-methylglutaryl-coenzyme A reductase. Underlying environmental and genetic risk factors remain poorly understood. American Indians have high rates of cardiovascular disease and associated co-morbidities that require lipid-lowering therapies. We observed this autoimmune myopathy in a series of American Indian statin users in rural Arizona. METHODS: We reviewed the charts of six American Indian patients with statin-associated autoimmune myopathy. We provide an illustrative case in addition to summaries of clinical presentations and treatment courses. RESULTS: This is the first report of statin-associated autoimmune myopathy in American Indians. These cases were all identified at the same geographically isolated hospital that exclusively serves an American Indian population with only 1800 statin users. There is relatively low migration. Each case was consistent with the previously described classical presentations for the disease. All six of our cases had diabetes and developed myopathy on high-dose atorvastatin, often with a recent change in statin type or dose. CONCLUSION: Providers serving American Indians need to be aware of the possibility of statin-associated autoimmune myopathy and familiar with its presentation. Larger, inclusive, population-based investigations are needed to elucidate risk factors for this condition, in particular the potential interactions between predisposing HLA alleles, diabetes and specific statin exposures. This is necessary to identify effective and safe lipid-lowering medications.

mRNA Reprogramming of T8993G Leigh's Syndrome Fibroblast Cells to Create Induced Pluripotent Stem Cell Models for Mitochondrial Disorders.

Early molecular and developmental events impacting many incurable mitochondrial disorders are not fully understood and require generation of relevant patient- and disease-specific stem cell models. In this study, we focus on the ability of a nonviral and integration-free reprogramming method for deriving clinical-grade induced pluripotent stem cells (iPSCs) specific to Leigh's syndrome (LS), a fatal neurodegenerative mitochondrial disorder of infants. The cause of fatality could be due to the presence of high abundance of mutant mitochondrial DNA (mtDNA) or decline in respiration levels, thus affecting early molecular and developmental events in energy-intensive tissues. LS patient fibroblasts (designated LS1 in this study), carrying a high percentage of mutant T8993G mtDNA, were reprogrammed using a combined mRNA-miRNA nonviral approach to generate human iPSCs (hiPSCs). The LS1-hiPSCs were evaluated for their self-renewal, embryoid body (EB) formation, and differentiation potential, using immunocytochemistry and gene expression profiling methods. Sanger sequencing and next-generation sequencing approaches were used to detect the mutation and quantify the percentage of mutant mtDNA in the LS1-hiPSCs and differentiated derivatives. Reprogrammed LS-hiPSCs expressed pluripotent stem cell markers including transcription factors OCT4, NANOG, and SOX2 and cell surface markers SSEA4, TRA-1-60, and TRA-1-81 at the RNA and protein level. LS1-hiPSCs also demonstrated the capacity for self-renewal and multilineage differentiation into all three embryonic germ layers. EB analysis demonstrated impaired differentiation potential in cells carrying high percentage of mutant mtDNA. Next-generation sequencing analysis confirmed the presence of high abundance of T8993G mutant mtDNA in the patient fibroblasts and their reprogrammed and differentiated derivatives. These results represent for the first time the derivation and characterization of a stable nonviral hiPSC line reprogrammed from a LS patient fibroblast carrying a high abundance of mutant mtDNA. These outcomes are important steps toward understanding disease origins and developing personalized therapies for patients suffering from mitochondrial diseases.