Klebsiella pneumoniae in the intestines of Musca domestica larvae can assist the host in antagonizing the poisoning of the heavy metal copper

BACKGROUND: Musca domestica larvae are common saprophytes in nature, promoting the material—energy cycle in the environment. However, heavy metal pollution in the environment negatively affects their function in material circulation. Our previous research found that some intestinal bacteria play an important role in the development of housefly, but the responses of microbial community to heavy metal stresses in Musca domestica is less studied. RESULTS: In this study, CuSO(4), CuSO(4)—Klebsiella pneumoniae mixture and CuSO(4)—K. pneumoniae phage mixture were added to the larval diet to analyze whether K. pneumoniae can protect housefly larvae against Cu(2+) injury. Our results showed that larval development was inhibited when were fed with CuSO(4), the bacterial abundance of Providencia in the intestine of larvae increased. However, the inhibition effects of CuSO(4) was relieved when K. pneumoniae mixed and added in larval diets, the abundance of Providencia decreased. Electron microscope results revealed that K. pneumoniae showed an obvious adsorption effect on copper ion in vitro. CONCLUSIONS: Based on the results we assume that K. pneumoniae could adsorb Cu(2+), reduce Cu(2+) impact on gut community structure. Our study explains the role of K. pneumoniae antagonizing Cu(2+), which could be applied as a probiotic to saprophytic bioantagonistic metal contamination.