Midgut Microbial Community of Culex quinquefasciatus Mosquito Populations from India

Abstract

The mosquito Culex quinquefasciatus is a ubiquitous species that serves as a major vector for west nile virus and lymphatic filariasis. Ingestion of bloodmeal by females triggers a series of physiological processes in the midgut and also exposes them to infection by these pathogens. The bacteria normally harbored in the midgut are known to influence physiology and can also alter the response to various pathogens. The midgut bacteria in female Cx. quinquefasciatus mosquitoes collected over a large geographical area from India was studied. Examination of 16S ribosomal DNA amplicons from culturable microflora revealed the presence of 83 bacterial species belonging to 31 bacterial genera. All of these species belong to three phyla i.e. Proteobacteria, Firmicutes and Actinobacteria. Phylum Proteobacteria was the most dominant phylum (37 species), followed by Firmicutes (33 species) and Actinobacteria (13 species). Phylum Proteobacteria, was dominated by members of γ-proteobacteria class. The genus Staphylococcus was the largest genus represented by 11 species whereas Enterobacter was the most prevalent genus and recovered from all the field stations except Leh. Highest bacterial prevalence was observed from Bhuj (22 species) followed by Nagrota (18 species), Masimpur (18 species) and Hathigarh (16 species). Whereas, least species were observed from Leh (8 species). It has been observed that individual mosquito harbor extremely diverse gut bacteria and have very small overlap bacterial taxa in their gut. This variation in midgut microbiota may be one of the factors responsible for variation in disease transmission rates or vector competence within mosquito population. The present data strongly encourage further investigations to verify the potential role of the detected bacteria in mosquito for the transmission of lymphatic filariasis and west nile virus. To the best of our knowledge this is the first study on midgut microbiota of wild Cx. quinquefasciatus from over a large geographical area.

Cultivable Bacterial Diversity in the Gut of the Chagas Disease Vector Triatoma dimidiata: Identification of Possible Bacterial Candidates for a Paratransgenesis Approach

“…Although in Rhodnius prolixus it was found to halt insect's development when applied to nymphs, in our study it was found in one of the field-collected insects and may be part of the natural occurring bacteria in T. dimidiata (Gumpert, 1962; Table 1). Staphylococcus homins, Staphylococcus lentus, and Staphylococcus nepalensis have all been reported previously in mites and distinct insect orders, with no apparent phenotypic traits associated for S. hominis (Rani et al, 2009;Chandel et al, 2013;Pandey et al, 2013;Maleki-Ravasan et al, 2015). Staphylococcus lentus and Staphylococcus nepalensis have been reported to be opportunistic pathogens in the haematophagous mite Dermanyssus gallinae (Valiente Moro et al, 2009).…”

“…Our analysis found that out of the 13 species identified in our study, Bacillus megaterium and S. saprophyticus appear to be the most common bacterial species described in other arthropods. A variety of studies globally have described both species in insects and mites (Aksoy and Ozman-Sullivan, 2008;Hillesland et al, 2008;Rani et al, 2009;Valiente Moro et al, 2009Joyce et al, 2011;Zouache et al, 2011;Mukhopadhyay et al, 2012;Palavesam et al, 2012;Chandel et al, 2013;He et al, 2013;Tagliavia et al, 2014;Zhang et al, 2014;Maleki-Ravasan et al, 2015). Of these two species, S. saprophyticus was the bacterial species that was most reported, but had no potential phenotypic traits associated with its arthropod hosts.…”

“…Therefore, it is unsurprising that previous studies have proposed B. megaterium for its use in paratransgenic studies of sand flies (which are vectors of Leishmaniasis) (Hillesland et al, 2008;Mukhopadhyay et al, 2012). Bacillus thuringiensis although well known for its insecticide use in GMO's, has few reports of being part of arthropod microbiotas (Chandel et al, 2013;Tagliavia et al, 2014), which makes sense given its insecticidal nature. In fact, an experiment by Nyirady (1973) showed that Rhodnius prolixus, also a vector of Chagas' disease, is killed when exposed to the subspecies thuringiensis.…”

Midgut bacterial diversity analysis of laboratory reared and wild Anopheles gambiae and Culex quinquefasciatus mosquitoes in Kenya

“…Field collected A. gambiae had the highest value of Inverse Simpson index and while the lowest was lab reared C. quinquefasciatus samples. The value of Inverse Simpson increases with diversity (Chandel et al, 2013). The Shannon index is another widely used index for comparing diversity between various habitats (Chandel et al, 2013).…”

The human immune system’s response to carcinogenic and other infectious agents transmitted by mosquito vectors

“…A comprehensive list of the main pathogens and parasites associated with mosquito vectors is available (see Murugan et al 2016). There are many less well known pathogens carried by mosquitoes, for example 83 bacterial species belonging to 31 bacterial genera in the midgut of Culex quinquefasciatus mosquitoes (Chandel et al 2013). All the species belong to three phyla, Proteobacteria, Firmicutes and Actinobacteria.…”