Simultaneous Detection of Six Diarrhea-Causing Bacterial Pathogens with an In-House PCR-Luminex Assay

Diarrhea can be caused by a range of pathogens, including several bacteria. Conventional diagnostic methods, such as culture, biochemical tests, and enzyme-linked immunosorbent assay (ELISA), are laborious. We developed a 7-plex PCR-Luminex assay to simultaneously screen for several of the major diarrhea-causing bacteria directly in fecal specimens, including pathogenic Aeromonas, Campylobacter jejuni, Campylobacter coli, Salmonella, Shigella, enteroinvasive Escherichia coli (EIEC), Vibrio, and Yersinia. We included an extrinsic control to verify extraction and amplification. The assay was first validated with reference strains or isolates and exhibited a limit of detection of 103 to 105 CFU/g of stool for each pathogen as well as quantitative detection up to 109 CFU/g. A total of 205 clinical fecal specimens from individuals with diarrhea, previously cultured for enteric pathogens and tested for Campylobacter by ELISA, were evaluated. Using these predicate methods as standards, sensitivities and specificities of the PCR-Luminex assay were 89% and 94% for Aeromonas, 89% and 93% for Campylobacter, 96% and 95% for Salmonella, 94% and 94% for Shigella, 92% and 97% for Vibrio, and 100% and 100% for Yersinia, respectively. All discrepant results were further examined by singleplex real-time PCR assays targeting different gene regions, which revealed 89% (55/62 results) concordance with the PCR-Luminex assay. The fluorescent signals obtained with this approach exhibited a statistically significant correlation with the cycle threshold (CT) values from the cognate real-time PCR assays (P < 0.05). This multiplex PCR-Luminex assay enables sensitive, specific, and quantitative detection of the major bacterial causes of gastroenteritis

From health crisis to rights advocacy? HIV/AIDS and gay activism in China and Singapore

The relationship between HIV/AIDS and gay activism has been primarily informed by the American experience and understudied in nondemocratic contexts. Drawing upon qualitative research on China and Singapore, we refine understanding of HIV/AIDS’ influence on the development of gay activism under authoritarian conditions, by examining the processes through which activist organizations interact with laws and regulations, political norms, HIV/AIDS funding, and government responses to both HIV/AIDS and collective organizing. We show how HIV/AIDS’ influence plays out in multiple patterns, depending on the strategic responses that gay activists select from a constrained range of options to shape their organizations’ destinies. Therefore, we provide insights for development agencies and international donors into whether and how international assistance intended to encourage activism and wider social change are mediated by political and legal controls on local activism