γ-Glutamyl transpeptidase has a role in the persistent colonization of the avian gut by Campylobacter jejuni

The contribution of gamma-glutamyl transpeptidase (GGT) to Campylobacter jejuni virulence and colonization of the avian gut has been investigated. The presence of the ggt gene in C jejuni strains directly correlated with the expression of GGT activity as measured by cleavage and transfer of the gamma-glutamyl moiety. Inactivation of the monocistronic ggt gene in C jejuni strain 81116 resulted in isogenic mutants with undetectable GGT activity; nevertheless, these mutants grew normally in vitro. However, the mutants had increased motility, a 5.4-fold higher invasion efficiency into INT407 cells in vitro and increased resistance to hydrogen peroxide stress. Moreover, the apoptosis-inducing activity of the ggt mutant was significantly lower than that of the parental strain. In vivo studies showed that., although GGT activity was not required for initial colonization of 1-day-old chicks, the enzyme was required for persistant colonization of the avian gut. (C) 2007 Elsevier Ltd. All rights reserved.