Diversity of symbiotic bacteria in the reproductive tracts and midgut of Culex pipiens

Background: Culex pipiens is considered a vector for the transmission of infectious, viral, and parasitic diseases. To control this mosquito vector, investigating symbiotic bacteria colonized inside the mosquitoes’ organs to impede the transmission of pathogens has been of recent interest to researchers. Methods: This revision was intended to provide a comprehensive overview of the diversity of endosymbiont bacteria residing in different tissues of Cx. pipiens globally by using reports in Google Scholar, PubMed, and Science Direct until May 2024. Result: The results showed that more than 50 bacterial genera have been reported in Culex tissues, in which the bacterial diversity was higher in the midgut than eggs or the whole body in Cx. pipiens. More than 65% of samples were insect-reared mosquitoes than wild types. Various methods based on culture-dependent and culture-independent approaches followed by molecular techniques such as 16SrRNA Illumina sequencing, Next Generation Sequencing (NGS), RNA shotgun metagenomic sequencing (RNA-seq), RTPCR, and MALDI-TOF MS have been used for the recognition of bacteria at genera or species levels. The most favorable gene for molecular analysis via PCR is 16SrRNA; however, the wsp gene was another candidate used for identification of the bacterial community. Conclusion: These results provide a library of defined bacteria associated with Cx. pipiens. The characterization of tissue-specific and host-specific bacterial communities sheds light on further studies pursuing the functional role of endosymbiont organisms in control strategies and vector biology.