Sub-inhibitory tigecycline concentrations induce extracellular matrix binding protein Embp dependent Staphylococcus epidermidis biofilm formation and immune evasion.
Biofilm-associated Staphylococcus epidermidis implant infections are notoriously reluctant to antibiotic treatment. Here we studied the effect of sub-inhibitory concentrations of penicillin, oxacillin, vancomycin, daptomycin, linezolid and tigecycline on S. epidermidis 1585 biofilm formation, expression of extracellular matrix binding protein (Embp) and potential implications for S. epidermidis - macrophage interactions. Penicillin, vancomycin, daptomycin, and linezolid had no biofilm augmenting effect at any of the concentrations tested. In contrast, at sub-inhibitory concentrations tigecycline and oxacillin exhibited significant biofilm inducing activity. In S. epidermidis 1585, SarA is a negative regulator of giant 1 MDa Embp, and down regulation of sarA induces Embp-dependent assembly of a multi-layered biofilm architecture. Dot blot immune assays, confocal laser scanning microscopy, and qPCR showed that under biofilm inducing conditions, tigecycline augmented embp expression compared to the control grown without antibiotics. Conversely, expression of regulator sarA was suppressed, suggesting that tigecycline exerts its effects on embp expression through SarA. Tigecycline failed to induce biofilm formation in embp transposon mutant 1585-M135, proving that under these conditions Embp up-regulation is necessary for biofilm accumulation. As a functional consequence, tigecycline induced biofilm formation significantly impaired the up-take of S. epidermidis by mouse macrophage-like cell line J774A.1. Our data provide novel evidence for the molecular basis of antibiotic induced biofilm formation, a phenotype associated with inherently increased antimicrobial tolerance. While this could explain failure of antimicrobial therapies, persistence of S. epidermidis infections in the presence of sub-inhibitory antimicrobials is additionally propelled by biofilm-related impairment of macrophage-mediated pathogen eradication.
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistraße 52, D-20246 Hamburg, Germany.
Julian
J
Weiser
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistraße 52, D-20246 Hamburg, Germany.
Hanae A
HA
Henke
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistraße 52, D-20246 Hamburg, Germany.
Nina
N
Hector
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistraße 52, D-20246 Hamburg, Germany.
Anna
A
Both
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistraße 52, D-20246 Hamburg, Germany.
Martin
M
Christner
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistraße 52, D-20246 Hamburg, Germany.
Henning
H
Büttner
Department of Biology, American University, Washington, DC 20016, USA.
Jeffery B
JB
Kaplan
Institut für Medizinische Mikrobiologie, Virologie und Hygiene, Universitätsklinikum Hamburg-Eppendorf, Martinistraße 52, D-20246 Hamburg, Germany. Electronic address: rohde@uke.uni-hamburg.de.
Holger
H
Rohde
D000818:Animals; D000900:Anti-Bacterial Agents / Q000378:metabolism*; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000235:genetics; D018441:Biofilms / Q000254:growth & development*; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000235:genetics; D002460:Cell Line; D020869:Gene Expression Profiling; D006801:Humans; D057131:Immune Evasion; D015151:Immunoblotting; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D018613:Microscopy, Confocal; D008911:Minocycline / Q000031:analogs & derivatives* / Q000378:metabolism; D010587:Phagocytosis; D060888:Real-Time Polymerase Chain Reaction; D013212:Staphylococcus epidermidis / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D000078304:Tigecycline; D015534:Trans-Activators / Q000096:biosynthesis / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D002352:Carrier Proteins; C469919:Embp32 protein, Staphylococcus epidermidis; C088021:SarA protein, bacterial; D015534:Trans-Activators; D000078304:Tigecycline; D008911:Minocycline
Antibiotic resistance; Biofilm formation; Extracellular matrix binding protein; Immune evasion; Persistence; Staphylococcus epidermidis