AUTHOR=Phuengmaung Pornpimol , Somparn Poorichaya , Panpetch Wimonrat , Singkham-In Uthaibhorn , Wannigama Dhammika Leshan , Chatsuwan Tanittha , Leelahavanichkul Asada 

TITLE=Coexistence of Pseudomonas aeruginosa With Candida albicans Enhances Biofilm Thickness Through Alginate-Related Extracellular Matrix but Is Attenuated by N-acetyl-l-cysteine

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=10

YEAR=2020

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2020.594336

DOI=10.3389/fcimb.2020.594336

ISSN=2235-2988

ABSTRACT=<p>Bacteria and <italic>Candida</italic><italic>albicans</italic> are prominent gut microbiota, and the translocation of these organisms into blood circulation might induce mixed-organism biofilms, which warrants the exploration of mixed- versus single-organism biofilms <italic>in vitro</italic> and <italic>in vivo</italic>. In single-organism biofilms, <italic>Acinetobacter baumannii</italic> and <italic>Pseudomonas aeruginosa</italic> (PA) produced the least and the most prominent biofilms, respectively. <italic>C. albicans</italic> with <italic>P. aeruginosa</italic> (PA+CA) induced the highest biofilms among mixed-organism groups as determined by crystal violet straining. The sessile form of PA+CA induced higher macrophage responses than sessile PA, which supports enhanced immune activation toward mixed-organism biofilms. In addition, <italic>Candida</italic> incubated in pre-formed <italic>Pseudomonas</italic> biofilms (PA&gt;CA) produced even higher biofilms than PA+CA (simultaneous incubation of both organisms) as determined by fluorescent staining on biofilm matrix (AF647 color). Despite the initially lower bacteria during preparation, bacterial burdens by culture in mixed-organism biofilms (PA+CA and PA&gt;CA) were not different from biofilms of PA alone, supporting <italic>Candida</italic>-enhanced <italic>Pseudomonas</italic> growth. Moreover, proteomic analysis in PA&gt;CA biofilms demonstrated high AlgU and mucA with low mucB when compared with PA alone or PA+CA, implying an alginate-related mucoid phenotype in PA&gt;CA biofilms. Furthermore, mice with PA&gt;CA biofilms demonstrated higher bacteremia with more severe sepsis compared with mice with PA+CA biofilms. This is possibly due to the different structures. Interestingly, <sc>l</sc>-cysteine, a biofilm matrix inhibitor, attenuated mixed-organism biofilms both <italic>in vitro</italic> and in mice. In conclusion, <italic>Candida</italic> enhanced <italic>Pseudomonas</italic> alginate–related biofilm production, and <italic>Candida</italic> presentation in pre-formed <italic>Pseudomonas</italic> biofilms might alter biofilm structures that affect clinical manifestations but was attenuated by <sc>l</sc>-cysteine.</p>