title: Intestinal tissues induce an SNP mutation in Pseudomonas aeruginosa that enhances its virulence: possible role in anastomotic leak.
abstract: The most feared complication following intestinal resection is anastomotic leakage. In high risk areas (esophagus/rectum) where neoadjuvant chemoradiation is used, the incidence of anastomotic leaks remains unacceptably high (≈ 10%) even when performed by specialist surgeons in high volume centers. The aims of this study were to test the hypothesis that anastomotic leakage develops when pathogens colonizing anastomotic sites become in vivo transformed to express a tissue destroying phenotype. We developed a novel model of anastomotic leak in which rats were exposed to pre-operative radiation as in cancer surgery, underwent distal colon resection and then were intestinally inoculated with Pseudomonas aeruginosa, a common colonizer of the radiated intestine. Results demonstrated that intestinal tissues exposed to preoperative radiation developed a significant incidence of anastomotic leak (>60%; p<0.01) when colonized by P. aeruginosa compared to radiated tissues alone (0%). Phenotype analysis comparing the original inoculating strain (MPAO1- termed P1) and the strain retrieved from leaking anastomotic tissues (termed P2) demonstrated that P2 was altered in pyocyanin production and displayed enhanced collagenase activity, high swarming motility, and a destructive phenotype against cultured intestinal epithelial cells (i.e. apoptosis, barrier function, cytolysis). Comparative genotype analysis between P1 and P2 revealed a single nucleotide polymorphism (SNP) mutation in the mexT gene that led to a stop codon resulting in a non-functional truncated protein. Replacement of the mutated mexT gene in P2 with mexT from the original parental strain P1 led to reversion of P2 to the P1 phenotype. No spontaneous transformation was detected during 20 passages in TSB media. Use of a novel virulence suppressing compound PEG/Pi prevented P. aeruginosa transformation to the tissue destructive phenotype and prevented anastomotic leak in rats. This work demonstrates that in vivo transformation of microbial pathogens to a tissue destroying phenotype may have important implications in the pathogenesis of anastomotic leak.
authors.affiliation: Department of Surgery, University of Chicago, Illinois, USA.
authors.forename: Andrea D
authors.initials: AD
authors.lastname: Olivas
authors.forename: Benjamin D
authors.initials: BD
authors.lastname: Shogan
authors.forename: Vesta
authors.initials: V
authors.lastname: Valuckaite
authors.forename: Alexander
authors.initials: A
authors.lastname: Zaborin
authors.forename: Natalya
authors.initials: N
authors.lastname: Belogortseva
authors.forename: Mark
authors.initials: M
authors.lastname: Musch
authors.forename: Folker
authors.initials: F
authors.lastname: Meyer
authors.forename: William L
authors.initials: WL
authors.lastname: Trimble
authors.forename: Gary
authors.initials: G
authors.lastname: An
authors.forename: Jack
authors.initials: J
authors.lastname: Gilbert
authors.forename: Olga
authors.initials: O
authors.lastname: Zaborina
authors.forename: John C
authors.initials: JC
authors.lastname: Alverdy
mesh_terms: D000714:Anastomosis, Surgical / Q000009:adverse effects; D057868:Anastomotic Leak / Q000382:microbiology* / Q000473:pathology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001483:Base Sequence; D017173:Caenorhabditis elegans; D003106:Colon / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D007422:Intestines / Q000187:drug effects / Q000382:microbiology* / Q000473:pathology / Q000648:ultrastructure; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D010710:Phosphates / Q000494:pharmacology; D011092:Polyethylene Glycols / Q000494:pharmacology; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D020011:Protective Agents / Q000494:pharmacology; D011550:Pseudomonas aeruginosa / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*; D011827:Radiation; D051381:Rats; D017208:Rats, Wistar; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism; D014945:Wound Healing / Q000187:drug effects; D062826:Zonula Occludens-1 Protein / Q000378:metabolism
chemical_list: D010710:Phosphates; D020011:Protective Agents; D062826:Zonula Occludens-1 Protein; D011092:Polyethylene Glycols