Development of a novel real-time polymerase chain reaction assay for the sensitive detection of Schistosoma japonicum in human stool.

BACKGROUND: Elimination and control of Schistosoma japonicum, the most virulent of the schistosomiasis-causing blood flukes, requires the development of sensitive and specific diagnostic tools capable of providing an accurate measurement of the infection prevalence in endemic areas. Typically, detection of S. japonicum has occurred using the Kato-Katz technique, but this methodology, which requires skilled microscopists, has been shown to radically underestimate levels of infection. With the ever-improving capabilities of next-generation sequencing and bioinformatic analysis tools, identification of satellite sequences and other highly repetitive genomic elements for use as real-time PCR diagnostic targets is becoming increasingly common. Assays developed using these targets have the ability to improve the sensitivity and specificity of results for epidemiological studies that can in turn be used to inform mass drug administration and programmatic decision making. METHODOLOGY/PRINCIPAL FINDINGS: Utilizing Tandem Repeat Analyzer (TAREAN) and RepeatExplorer2, a cluster-based analysis of the S. japonicum genome was performed and a tandemly arranged genomic repeat, which we named SjTR1 (Schistosoma japonicum Tandem Repeat 1), was selected as the target for a real-time PCR diagnostic assay. Based on these analyses, a primer/probe set was designed and the assay was optimized. The resulting real-time PCR test was shown to reliably detect as little as 200 ag of S. japonicum genomic DNA and as little as 1 egg per gram of human stool. Based on these results, the index assay reported in this manuscript is more sensitive than previously published real-time PCR assays for the detection of S. japonicum. CONCLUSIONS/SIGNIFICANCE: The extremely sensitive and specific diagnostic assay described in this manuscript will facilitate the accurate detection of S. japonicum, particularly in regions with low levels of endemicity. This assay will be useful in providing data to inform programmatic decision makers, aiding disease control and elimination efforts.

Factors associated with progression to infection in methicillin-resistant Staphylococcus aureus-colonized, critically ill neonates.

OBJECTIVE: To identify factors associated with development of symptomatic infection in infants colonized with methicillin-resistant Staphylococcus aureus (MRSA) in the Neonatal Intensive Care Unit (NICU). STUDY DESIGN: This case-control study was performed at St. Louis Children's Hospital NICU from 2009 to 2019. The MRSA-colonized infants who developed symptomatic MRSA infection (cases) were matched 1:3 with MRSA-colonized infants who did not develop infection (controls). Demographics and characteristics of NICU course were compared between groups. Longitudinal information from subsequent hospitalizations was also obtained. RESULTS: Forty-two infected cases were compared with 126 colonized-only controls. Cases became colonized earlier in their NICU stay, were less likely to have received mupirocin for decolonization, and had a longer course of mechanical ventilation than controls. Longitudinally, cases had a more protracted NICU course and were more likely to require hospital readmission. CONCLUSION: Progression from MRSA colonization to symptomatic infection is associated with increased morbidity and may be mitigated through decolonization.