Abstract
Serratia marcescens is a bacterium with the ability to colonize several niches, including some eukaryotic hosts. S. marcescens have been recently found in the gut of hematophagous insects that act as parasite vectors, such as Anopheles, Rhodnius, and Triatoma. While some S. marcescens strains have been reported as symbiotic or pathogenic to other insects, the role of S. marcescens populations from the gut microbiota of Rhodnius prolixus, a vector of Chagas’ disease, remains unknown. Bacterial colonies from R. prolixus gut were isolated on BHI agar. After BOX-PCR fingerprinting, the genomic sequences of two isolates RPA1 and RPH1 were compared to others S. marcescens from the NCBI database in other to estimate their evolutionary divergence. The in vitro trypanolytic activity of these two bacterial isolates against Trypanosoma cruzi (DM28c clone and Y strain) was assessed by microscopy. In addition, the gene expression of type VI secretion system (T6SS) was detected in vivo by RT-PCR. Comparative genomics of RPA1 and RPH1 revealed, besides plasmid presence and genomic islands, genes related to motility, attachment, and quorum sensing in both genomes while genes for urea hydrolysis and type II secretion system (T2SS) were found only in the RPA1 genome. The in vitro trypanolytic activity of both S. marcescens strains was stronger in their stationary phases of growth than in their exponential ones, with 65–70 and 85–90% of epimastigotes (Dm28c clone and Y strain, respectively) being lysed after incubation with RPA1 or RPH1 in stationary phase. Although T6SS transcripts were detected in guts up to 40 days after feeding (DAF), R. prolixus morbidity or mortality did not appear to be affected. In this report, we made available two trypanolytic S. marcescens strains from R. prolixus gut to the scientific community together with their genomic sequences. Here, we describe their genomic features with the purpose of bringing new insights into the S. marcescens adaptations for colonization of the specific niche of triatomine guts. This study provides the basis for a better understanding of the role of S. marcescens in the microbiota of R. prolixus gut as a potential antagonist of T. cruzi in this complex system.
Highlights
Trypanosoma cruzi is a protozoan parasite that causes Chagas disease, a neglected disease that affects six to seven million people worldwide and is transmitted by triatomines, which are insect vectors from the family of Reduviidae (Coura, 2015; World Health Organization [WHO], 2018)
The rabbit blood was obtained according to the ethical principles in animal experimentation approved by the Comissão de Ética no Uso de Animais from Oswaldo Cruz Foundation (CEUA/FIOCRUZ) under the protocol number LW019/17 following the recommendations of Ministério da Ciência, Tecnologia e Inovação/Conselho Nacional de Controle de Experimenyação Animal (MCTI/CONCEA) available at http://pages.cnpem.br/ceua/wpcontent/uploads/sites/56/2015/06/DBCA.pdf, which is approved by the Federation of European Laboratory Animal Science Associations (FELASA), the American Association for Animal Science (AAAS), the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC), and the International Council for Animal Science (ICLAS)
We reported on the genomes of two S. marcescens strains isolated from the gut microbiota of R. prolixus and made available publicly through DDBJ/ENA/GenBank
Summary
Trypanosoma cruzi is a protozoan parasite that causes Chagas disease ( known as American Trypanosomiasis), a neglected disease that affects six to seven million people worldwide and is transmitted by triatomines, which are insect vectors from the family of Reduviidae (Coura, 2015; World Health Organization [WHO], 2018). Chagas disease has been reported mainly in Latin America where it is endemic in 21 countries, but over the past decades, it has been detected in the United States, Canada, Europe, and some Western Pacific countries (Coura and Viñas, 2010; World Health Organization [WHO], 2018) due to infected people emigration and blood transfusion (Hernández-Romano et al, 2015). The re-infestation by triatomines of different species, such as Triatoma brasiliensis and Triatoma pseudomaculata, infected with T. cruzi, has been notified in endemic areas to replace Triatoma infestans, the original triatomine vector (Coura and Viñas, 2010; Pessoa et al, 2015; Barbosa-Silva et al, 2016)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
