Biofilm vs. planktonic bacterial mode of growth: which do human macrophages prefer?
Although the natural mode of bacterial growth in nature is as biofilm, almost all antimicrobial and immunological tests are routinely developed using planktonic inoculums. Bacterial biofilms protect the microbial community from external damage and promote the persistence of chronic infections. In this study, interactions between human macrophages and bacterial inoculums of planktonic and biofilm modes of growth have been explored using Escherichia coli (E. coli) K12. Human macrophages phagocytize planktonic E. coli more efficiently than bacteria grown in a biofilm. Moreover, they prefer to phagocytize planktonic bacteria. In this context, CD64 expression is involved. Our data indicate that bacteria with "a biofilm background" avoid phagocytosis by naïve macrophages, which could create a favorable environment for chronic infection. Our findings were corroborated in a clinical O25b-ST131 ESBL-producer E. coli isolate, which caused urinary tract infections.
Tumor Immunology Laboratory, IdiPAZ, La Paz Hospital, Spain.
Enrique
E
Hernández-Jiménez
Rosa
R
Del Campo
Victor
V
Toledano
Maria Teresa
MT
Vallejo-Cremades
Aurora
A
Muñoz
Carlota
C
Largo
Francisco
F
Arnalich
Francisco
F
García-Rio
Carolina
C
Cubillos-Zapata
Eduardo
E
López-Collazo
D001419:Bacteria / Q000254:growth & development*; D018441:Biofilms; D002478:Cells, Cultured; D004926:Escherichia coli / Q000201:enzymology / Q000254:growth & development; D006801:Humans; D008264:Macrophages / Q000276:immunology* / Q000382:microbiology*; D010587:Phagocytosis; D010933:Plankton; D017452:Receptors, IgG / Q000276:immunology; D014552:Urinary Tract Infections / Q000276:immunology / Q000382:microbiology; D001618:beta-Lactamases / Q000378:metabolism
C489017:FCGR1A protein, human; D017452:Receptors, IgG; D001618:beta-Lactamases
Biofilm; Human macrophages; Phagocytosis; Planktonic