Genomic, Physiologic, and Symbiotic Characterization of Serratia marcescens Strains Isolated from the Mosquito Anopheles stephensi

Abstract

Strains of Serratia marcescens, originally isolated from the gut lumen of adult female Anopheles stephensi mosquitoes, established persistent infection at high rates in adult A. stephensi whether fed to larvae or in the sugar meal to adults. By contrast, the congener S. fonticola originating from Aedes triseriatus had lower infection in A. stephensi, suggesting co-adaptation of Serratia strains in different species of host mosquitoes. Coinfection at high infection rate in adult A. stephensi resulted after feeding S. marcescens and Elizabethkingia anophelis in the sugar meal, but when fed together to larvae, infection rates with E. anophelis were much higher than were S. marcescens in adult A. stephensi, suggesting a suppression effect of coinfection across life stages. A primary isolate of S. marcescens was resistant to all tested antibiotics, showed high survival in the mosquito gut, and produced alpha-hemolysins which contributed to lysis of erythrocytes ingested with the blood meal. Genomes of two primary isolates from A. stephensi, designated S. marcescens ano1 and ano2, were sequenced and compared to other Serratia symbionts associated with insects, nematodes and plants. Serratia marcescens ano1 and ano2 had predicted virulence factors possibly involved in attacking parasites and/or causing opportunistic infection in mosquito hosts. S. marcescens ano1 and ano2 possessed multiple mechanisms for antagonism against other microorganisms, including production of bacteriocins and multi-antibiotic resistance determinants. These genes contributing to potential anti-malaria activity including serralysins, hemolysins and chitinases are only found in some Serratia species. It is interesting that genome sequences in S. marcescens ano1 and ano2 are distinctly different from those in Serratia sp. Ag1 and Ag2 which were isolated from Anopheles gambiae. Compared to Serratia sp. Ag1 and Ag2, S. marcescens ano1 and ano2 have more rRNAs and many important genes involved in commensal and anti-parasite traits.

The Emerging Fish Pathogen Flavobacterium spartansii Isolated from Chinook Salmon: Comparative Genome Analysis and Molecular Manipulation

“…Hemolysin production in F. spartansii T16 T was examined by inoculating bacteria on Remel Blood Agar (Thermo Scientific, KS). Hemolytic activity was evaluated following incubation at 28°C for 48 h. The controls for α- and β-hemolysin producers were Elizabethkingia meningoseptica ATCC 13253 and Staphylococcus aureus MSU001, respectively (Chen et al, 2017 ).…”

Altered gut microbiota and immunity defines Plasmodium vivax survival in Anopheles stephensi

“…(Falvibacteriace), Pseudomonas (Pseudomonadales), and Serratia (Enterobacteriace). Previous several studies have also reported a similar pattern of gut microbe enrichment (Tchioffo, Boissiere et al 2015;Muturi, Dunlap et al 2019), but nature of gutmicrobe interactions, especially microbial proteins facilitating blood meal digestion, remains poorly known (Chen, Blom et al 2017). Available draft genome sequence of cultured bacterial species predicts several metabolic pathways, but no functional relation has been established (Kukutla, Lindberg et al 2013;Pei, Hill-Clemons et al 2015).…”

In vitro Trypanocidal Activity, Genomic Analysis of Isolates, and in vivo Transcription of Type VI Secretion System of Serratia marcescens Belonging to the Microbiota of Rhodnius prolixus Digestive Tract

“…T2SS was observed only in RPA1, which could explain its higher trypanolytic activity compared to that of RPH1. This secretion system was also detected in S. marcescens strains Ano1 and Ano2, from A. stephensi (Chen et al, 2017), although the mechanism that could interfere with the Plasmodium development in the mosquito midgut has not been described yet.…”