The surveillance of prevalent Leishmania and sand fly species in endemic areas is important for prediction of the risk and expansion of leishmaniasis. In this study, we developed a polymerase chain reaction (PCR)-based method for detection of Leishmania minicircle DNA within individual sand flies. Using this method, we detected minicircle DNA in 6 (3.3%) of 183 sand flies, while 5 (3.5%) of 143 were positive for Leishmania promastigotes in the same areas by microscopic examination. The species were identified as Leishmania (Leishmania) mexicana by nucleotide sequencing of the cytochrome b gene. Additionally, all the Leishmania-positive sand flies were identified as Lutzomyia ayacuchensis by the restriction enzyme digestion of the PCR-amplified 18S ribosomal RNA gene fragments. Since this combined method is relatively easy and can process a large number of samples, it will be a powerful tool for the rapid identification of prevalent sand fly and Leishmania species as well as monitoring the infection rate in sand fly populations in endemic areas.

Background: Antimicrobial resistance is a serious public-health problem throughout the world. Escherichia coli, the most common Gram-negative microorganism, has developed different resistance mechanisms, making treating infections difficult. Colistin is considered a last-resort drug in the treatment of infections caused by E. coli. Plasmid-mediated mobile-colistin-resistant (mcr) genes in E. coli, now disseminated globally, are considered a major public-health threat. Humans, chickens, and pigs are the main reservoirs for E. coli and the sources of antibiotic resistance. Hence, an up-to-date and precise estimate of the global prevalence of mcr resistance genes in these reservoirs is necessary to understand more precisely the worldwide spread and to more effectively implement control and prevention strategies. Methodology: Publications were identified in the PubMed database on the basis of the PRISMA guidelines. English full-text articles were selected from December 2014 to March 2021. Descriptive statistics and a meta-analysis were performed in Excel and R software, respectively. Colistin resistance was defined as the molecular-genetic detection of the mcr genes. The crude and estimated prevalence were calculated for each host and continent. The studies were divided into two groups; community-based when they involved isolates from healthy humans, chickens, or pigs, and clinical studies when they involved only hospital, outpatient, or laboratory isolates. Results: A total of 1278 studies were identified and 218 were included in this systematic review and meta-analysis, divided into community studies (159 studies) and clinical studies (59 studies). The general prevalence of mcr-mediated colistin-resistant E. coli (mcrMCRE) was 6.51% (n = 11,583/177,720), reported in 54 countries and on five continents; Asia with 119 studies followed by Europe with 61 studies registered the most articles. Asia reported the major diversity of mcr-variants (eight of nine, except mcr-2). Worldwide, chickens and pigs proved to be the principal reservoir of mcr with an estimated prevalence of 15.8% and 14.9%, respectively. Healthy humans and clinical isolates showed a lower prevalence with 7.4% and 4.2% respectively. Conclusions: In this systematic review and meta-analysis, the worldwide prevalence of mcr in E. coli isolated from healthy humans, chickens, and pigs was investigated. A wide prevalence and distribution of mcr genes was demonstrated on all continents in E. coli isolates from the selected reservoirs. Understanding the epidemiology and occurrence in the reservoirs of mcr in E. coli on different continents of the world facilitates tracing how mcr genes are transmitted and determining the infection risks for humans. This knowledge can be used to reduce the incidence of zoonotic transmission by implementing the appropriate control programs.

Immunity to Onchocerca volvulus (Ov) infection is suggested by the presence of putatively immune (PI) subjects in a region of Ecuador in which Ov is endemic. PI subjects were identified by traditional diagnostic methods combined with a polymerase chain reaction-based assay for Ov DNA in skin snips. Responses of peripheral blood mononuclear cells (PBMC) from the PI group (n = 16) were compared with those of persons with active infection (microfiladermic [MF] subjects; n = 51). PBMC of PI subjects proliferated significantly more to Ov antigen (OvAg; P < .009) than did PBMC ofMF persons but less to streptolysin-O (P < .001). Cytokine analysis of PBMC culture supernatants revealed that PI subjects (n = 11) produced significantly more interferon-ã to OvAg than did those in the MF group (n = 18; P = .018), less interleukin (IL)-5 to nonparasite antigen (P = .003) and mitogen (P = .012), and less IL-I0 spontaneously (P = .016). Thus, immunity to Ov may in part be mediated by an antigen-specific Th I-type response.

Purpose: Extended-spectrum beta-lactamase-producing (ESBL) Enterobacteriaceae, which includes Escherichia coli, has emerged as a global health threat. ESBL enzymes including CTX-M, TEM, and SHV are the most detected. Here, a systematic review was developed to assess the status of ESBLs in E. coli considering studies performed in the human, animal, food, and environmental realms in South America. Methods: Following PRISMA guidelines, a systematic review was performed using the PubMed database as a primary source to identify studies containing data on ESBL-producing E. coli in South America. To obtain a comprehensive sample, studies in English, Spanish, and Portuguese were included from 1990 to April 2021. Inclusion such as the reporting of sample origin and diagnostic method and exclusion criteria such as review/letter articles were established to complete data extraction steps. Results: Amongst 506 articles retrieved, 130 met the inclusion criteria. Brazil reported 65 (50%) of publications, followed by Argentina, and Ecuador with 11.5% each. According to the category of studies, human studies represented the 56%, animals the 20%, environmental the 11%, and food studies the 6%. Interestingly, studies assessing more than one category (ie, interdisciplinary) represented the 7%. Prevalence of ESBL producing E. coli in animal, food, and environmental studies was widely superior compared to human sources. In clinical studies, Brazil presented the greatest diversity in terms of ESBLs, featuring CTX-M, TEM, SHV, TOHO, OXA, and AmpC. CTX-M enzymes were the most frequent variants with 89.4% detections. Conclusion: The present One Health review of 130 studies conducted over the past 21 years found ESBLs producing E. coli distributed across human, animal, food, and environmental samples across South America. There is a need to increment studies in underrepresented countries and to strengthen multi-sectoral antimicrobial resistance research and surveillance. This information can be used as basis for subsequent implementation of monitoring programs, targeting potential critical points of transmission sources.