Selective bowel decontamination results in gram-positive translocation.
Colonization by enteric gram-negative bacteria with subsequent translocation is believed to be a major mechanism for infection in the critically ill patient. Selective bowel decontamination (SBD) has been used to control gram-negative infections by eliminating these potentially pathogenic bacteria while preserving anaerobic and other less pathogenic organisms. Infection with gram-positive organisms and anaerobes in two multivisceral transplant patients during SBD led us to investigate the effect of SBD on gut colonization and translocation.


METHODS
Twenty-four rats received enteral polymixin E, tobramycin, amphotericin B, and parenteral cefotaxime for 7 days (PTA + CEF); 23 received parenteral cefotaxime alone (CEF), 19 received the enteral antibiotics alone (PTA), 21 controls received no antibiotics. Cecal homogenates, mesenteric lymph node (MLN), liver, and spleen were cultured.


RESULTS
Only 8% of the PTA + CEF group had gram-negative bacteria in cecal culture vs 52% CEF, 84% PTA, and 100% in controls. Log Enterococcal colony counts were higher in the PTA + CEF group (8.0 + 0.9) vs controls (5.4 + 0.4) P less than 0.01. Translocation of Enterococcus to the MLN was significantly increased in the PTA + CEF group (67%) vs controls (0%) P less than 0.01. SBD effectively eliminates gram-negative organisms from the gut in the rat model. Overgrowth and translocation of Enterococcus suggests that infection with gram-positive organisms may be a limitation of SBD.
Jackson
R J
RJ
University of Pittsburgh School of Medicine, Division of Pediatric Surgery, Pennsylvania.
Smith
S D
SD
Rowe
M I
MI
D000818:Animals; D001421:Bacteria, Anaerobic / Q000302:isolation & purification; D002432:Cecum / Q000382:microbiology; D003114:Colony-Forming Units Assay; D003666:Decontamination; D006090:Gram-Negative Bacteria / Q000302:isolation & purification; D006094:Gram-Positive Bacteria / Q000302:isolation & purification / Q000502:physiology*; D007422:Intestines / Q000382:microbiology*; D008198:Lymph Nodes / Q000382:microbiology; D008297:Male; D008643:Mesentery; D011549:Pseudomonas / Q000302:isolation & purification; D051381:Rats; D011919:Rats, Inbred Strains