%0 Journal Article %A Sheehan, Gerard %A Tully, Laura %A Kavanagh, Kevin A. %T Candida albicans increases the pathogenicity of Staphylococcus aureus during polymicrobial infection of Galleria mellonella larvae %D 2020 %J Microbiology, %V 166 %N 4 %P 375-385 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.000892 %K co-infection %K infection %K Staphylococcus %K Candida %K mini-model %K immunity %K Galleria %I Microbiology Society, %X This study detailed the responses of Galleria mellonella larvae to disseminated infection caused by co-infection with Candida albicans and Staphylococcus aureus . Doses of C. albicans (1×105 larva−1) and S. aureus (1×104 larva−1) were non-lethal in mono-infection but when combined significantly (P<0.05) reduced larval survival at 24, 48 and 72 h relative to larvae receiving S. aureus (2×104 larva−1) alone. Co-infected larvae displayed a significantly higher density of S. aureus larva−1 compared to larvae infected solely with S. aureus . Co-infection resulted in dissemination throughout the host and the appearance of large nodules. Co-infection of larvae with C. albicans and S. aureus (2×104 larva−1) resulted in an increase in the density of circulating haemocytes compared to that in larvae infected with only S. aureus . Proteomic analysis of co-infected larval haemolymph revealed increased abundance of proteins associated with immune responses to bacterial and fungal infection such as cecropin-A (+45.4-fold), recognition proteins [e.g. peptidoglycan-recognition protein LB (+14-fold)] and proteins associated with nodule formation [e.g. Hdd11 (+33.3-fold)]. A range of proteins were also decreased in abundance following co-infection, including apolipophorin (−62.4-fold), alpha-esterase 45 (−7.7-fold) and serine proteinase (−6.2-fold). Co-infection of larvae resulted in enhanced proliferation of S. aureus compared to mono-infection and an immune response showing many similarities to the innate immune response of mammals to infection. The utility of G. mellonella larvae for studying polymicrobial infection is highlighted. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000892