Trichomonas vaginalis exosome-like vesicles modify the cytokine profile and reduce inflammation in parasite-infected mice.

Trichomonas vaginalis (Tv) is a flagellated parasite commonly spread through sexual transmission. This protozoan initiates a severe inflammatory process, inducing nitric oxide, interleukin-6 (IL-6), IL-8, IL-10, IL-17 and IL-22 production by host immune cells. The parasites elicit these responses by releasing surface lipophosphoglycan, small extracellular vesicles (exosomes) and other factors. Tv exosomes are similar to mammalian exosomes and have been implicated in the modulation of IL-8 secretion by epithelial cells. Here, we report that exosome-like vesicles from T. vaginalis (Tv-ELVs) induced a more than 15-fold increase in IL-10 expression in RAW264.7 macrophages but only a two fold increase in IL-6 and TNF-α expression levels measured by RT-PCR. Because Tv-ELVs modulated the macrophage response, we also explored the effect of Tv-ELVs in a murine model of infection. Pretreatment with Tv-ELVs significantly increased IL-10 production as measured in vaginal washes by days 8 and 16 post-infection. Remarkably, Tv-ELVs-pretreated mice exhibited a decrease in IL-17 production and a significant decrease in vulvar inflammation. In addition, IL-6 and IL-13 were decreased during infection. Our results suggest that Tv-ELVs have an immunomodulatory role on the cytokine profile induced by the parasite and promote a decrease in the inflammatory process in mice infected with T. vaginalis.

A PCR procedure for the detection of Giardia intestinalis cysts and Escherichia coli in lettuce.

Giardia intestinalis is a pathogen associated with foodborne outbreaks and Escherichia coli is commonly used as a marker of faecal contamination. Implementation of routine identification methods of G. intestinalis is difficult for the analysis of vegetables and the microbiological detection of E. coli requires several days. This study proposes a PCR-based assay for the detection of E. coli and G. intestinalis cysts using crude DNA isolated from artificially contaminated lettuce. The G. intestinalis and E. coli PCR assays targeted the ß-giardin and uidA genes, respectively, and were 100% specific. Forty lettuces from local markets were analysed by both PCR and light microscopy and no cysts were detected, the calculated detection limit was 20 cysts per gram of lettuce; however, by PCR, E. coli was detected in eight of ten randomly selected samples of lettuce. These data highlight the need to validate procedures for routine quality assurance. These PCR-based assays can be employed as alternative methods for the detection of G. intestinalis and E. coli and have the potential to allow for the automation and simultaneous detection of protozoa and bacterial pathogens in multiple samples. Significance and impact of the study: There are few studies for Giardia intestinalis detection in food because methods for its identification are difficult for routine implementation. Here, we developed a PCR-based method as an alternative to the direct observation of cysts in lettuce by light microscopy. Additionally, Escherichia coli was detected by PCR and the sanitary quality of lettuce was evaluated using molecular and standard microbiological methods. Using PCR, the detection probability of Giardia cysts inoculated onto samples of lettuce was improved compared to light microscopy, with the advantage of easy automation. These methods may be employed to perform timely and affordable detection of foodborne pathogens.