Intestinal Enterococcus faecium colonization improves host defense during polymicrobial peritonitis.
BACKGROUND
Vancomycin-resistant (VR) Enterococcus faecium is increasingly found to colonize and infect hospitalized patients. Enterococci are frequently isolated from polymicrobial infections originating from the intestines. The impact of VR E. faecium on these infections and vice versa is not clear.


METHODS
Mice were intestinally colonized with VR E. faecium during oral vancomycin treatment; control mice received oral vancomycin only. Fourteen days later, cecal ligation and puncture (CLP) was performed in all mice to induce polymicrobial peritonitis in the presence or absence of VR E. faecium colonization.


RESULTS
VR E. faecium colonization per se was not associated with systemic dissemination of VR E. faecium. CLP resulted in systemic VR E. faecium infection in all VR E. faecium-colonized mice, with high VR E. faecium loads in peritoneal lavage fluid, blood, liver, and lungs. Forty-eight hours after CLP, mice infected with VR E. faecium had significantly lower bacterial loads in all organs tested than mice not infected with VR E. faecium. Additionally, lower inflammatory parameters were measured in VR E. faecium-infected mice. CLP induced transient liver and kidney damage, with a faster recovery in VR E. faecium-colonized mice.


CONCLUSIONS
VR E. faecium infection, originating from a natural source (the intestinal tract), does not worsen the outcome of CLP-induced polymicrobial peritonitis and sepsis but rather facilitates bacterial clearance and attenuates host inflammatory responses.
Leendertse
Masja
M
Center for Infection and Immunity Amsterdam (CINIMA), Academic Medical Center, Amsterdam, The Netherlands. m.leendertse@amc.uva.nl
Willems
Rob J L
RJ
Oei
G Anneke
GA
Florquin
Sandrine
S
Bonten
Marc J M
MJ
van der Poll
Tom
T
D000818:Animals; D001202:Ascitic Fluid / Q000382:microbiology; D001419:Bacteria / Q000302:isolation & purification; D001424:Bacterial Infections / Q000276:immunology* / Q000473:pathology; D001769:Blood / Q000382:microbiology; D002353:Carrier State / Q000276:immunology* / Q000382:microbiology*; D015169:Colony Count, Microbial; D016207:Cytokines / Q000097:blood; D016984:Enterococcus faecium / Q000187:drug effects / Q000254:growth & development* / Q000276:immunology*; D005260:Female; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D008099:Liver / Q000382:microbiology / Q000473:pathology; D008168:Lung / Q000382:microbiology / Q000473:pathology; D051379:Mice; D010538:Peritonitis / Q000276:immunology* / Q000473:pathology; D020713:Vancomycin Resistance
D016207:Cytokines