AUTHOR=Laviad Sivan , Halpern Malka 

TITLE=Chironomids’ Relationship with Aeromonas Species

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.00736

DOI=10.3389/fmicb.2016.00736

ISSN=1664-302X

ABSTRACT=<p>Chironomids (<italic>Diptera: Chironomidae</italic>), also known as non-biting midges, are one of the most abundant groups of insects in aquatic habitats. They undergo a complete metamorphosis of four life stages of which three are aquatic (egg, larva, and pupa), and the adult emerges into the air. Chironomids serve as a natural reservoir of <italic>Aeromonas</italic> and <italic>Vibrio cholerae</italic> species. Here, we review existing knowledge about the mutual relations between <italic>Aeromonas</italic> species and chironomids. Using 454-pyrosequencing of the 16S rRNA gene, we found that the prevalence of <italic>Aeromonas</italic> species in the insects’ egg masses and larvae was 1.6 and 3.3% of the insects’ endogenous microbiota, respectively. <italic>Aeromonas</italic> abundance per egg mass remained stable during a 6-month period of bacterial monitoring. Different <italic>Aeromonas</italic> species were isolated and some demonstrated the ability to degrade the insect’s egg masses and to prevent eggs hatching. Chitinase was identified as the enzyme responsible for the egg mass degradation. Different <italic>Aeromonas</italic> species isolated from chironomids demonstrated the potential to protect their host from toxic metals. <italic>Aeromonas</italic> is a causative agent of fish infections. Fish are frequently recorded as feeding on chironomids. Thus, fish might be infected with <italic>Aeromonas</italic> species via chironomid consumption. <italic>Aeromonas</italic> strains are also responsible for causing gastroenteritis and wound infections in humans. Different virulence genes were identified in <italic>Aeromonas</italic> species isolated from chironomids. Chironomids may infest drinking water reservoirs, hence be the source of pathogenic <italic>Aeromonas</italic> strains in drinking water. Chironomids and <italic>Aeromonas</italic> species have a complicated mutual relationship.</p>