Epsilonproteobacteria in Humans, New Zealand

Angela J. Cornelius, Stephen Chambers, John Aitken, Stephanie M. Brandt, Beverley Horn, and Stephen L.W. On

Author affiliations: Institute of Environmental Science and Research, Christchurch, New Zealand (A.J. Cornelius, S.M. Brandt, B. Horn, S.L.W. On); Christchurch School of Medicine, Christchurch (S.T. Chambers); Southern Community Laboratories, Christchurch (J. Aitken)

Abstract

Using PCR–denaturing gradient gel electrophoresis, we examined 49 fecal samples from healthy volunteers and 128 diarrhea specimens to assess the distribution of Epsilonproteobacteria that might be routinely overlooked. Our results suggest that certain taxa that are not routinely examined for could account for a proportion of diarrhea of previously unknown etiology.

Acute gastrointestinal illness is a major health concern in industrialized countries. In New Zealand, an estimated 4.6 million cases of acute gastrointestinal illness occur every year (1). For many known causes of acute gastrointestinal illness, conventional methods of diagnosis are available; yet, ≈80% of diarrhea cases go undiagnosed (1,2). This lack of data concerning causes of diarrhea hinders the development of intervention strategies.

The class Epsilonproteobacteria is a distinct, diverse bacterial group containing ≈100 taxa (3), including Campylobacter jejuni, recognized as the most frequent bacterial cause of human gastroenteritis worldwide (4,5). Many other epsilonproteobacterial species have been associated with diarrhea, but accurate estimates of the prevalence and role of individual species and proof of a primary pathogenic role have been elusive. Methods commonly used for isolating C. jejuni are not well suited for many other species, and the complex taxonomy of the group makes identification difficult (4). Nevertheless, the body of evidence supporting a causative role for several taxa has grown (5–7). During September 2007–June 2009, we examined fecal samples from healthy volunteers and from patients with diarrhea in New Zealand by using a PCR–denaturing gradient gel electrophoresis (DGGE) method shown to detect and identify Epsilonproteobacteria (8).