Green bottle flies occur frequently around human
environments in Japan. Many species of green bottle flies
have been studied with regard to their importance in forensic
examinations or clinical therapies, but the bacterial communities
associated with this group of flies have not been comprehensively
investigated. In this research, 454 pyrosequencing
was used to reveal the bacterial communities in green
bottle flies collected in different seasons. Meanwhile, the
bacteria were screened with selective media and tested for
antibiotic susceptibility. Samples collected in three different
seasons harbored distinctive bacterial communities. The predominant
genera associated with green bottles flies were
Staphylococcus in spring, Ignatzschineria in summer, and
Vagococcus, Dysgonomonas, and an unclassified
Acetobacteraceae in autumn. An upward trend in bacterial
community diversity was observed from spring to autumn.
Changes in climatic conditions could be the cause of these
seasonal variations in fly-associated bacterial communities.
The species of isolated antibiotic-resistant bacteria also differed
across seasons, but it was difficult to correlate seasonal
changes in antibiotic-resistant bacteria with changes in whole
communities. A number of multiple-antibiotic-resistant bacteria
were isolated, and some of these strains were closely
affiliated with pathogens such as Enterococcus faecalis and
Enterococcus faecium, which could cause serious threats to
public health. Overall, this research provided us with information
about the composition and seasonality of bacterial
communities in green bottle flies, and highlighted the risks
of fly-mediated dissemination of antibiotic-resistant
pathogens.