Campylobacters and bacteriophages in the surface waters of Canterbury (New Zealand).

AIM

To determine the relationship between the presence of thermotolerant campylobacters and their bacteriophages (phages) in surface waters for the potential to use phages as an indicator of Campylobacter spp.

METHODS AND RESULTS

Thermotolerant campylobacters were enumerated in 53 water samples using a three tube most probable number (MPN) series in m-Exeter broth. The presence of phages in the same samples was tested using two approaches: qualitative enrichment with five different Campylobacter hosts and a quantitative membrane concentration method. Phages infecting an Escherichia coli O157:H7 isolate were also enumerated by the membrane concentration method. Campylobacter spp. were isolated from 45/53 (85%) of the samples at 0.4-110 MPN 100 ml(-1). No Campylobacter phages were isolated, but coliphages were present in 43/46 (93%) of samples.

CONCLUSIONS

The membrane concentration method recovered >80% of Campylobacter phages from spiked samples. The absence of Campylobacter phages in environmental samples, from both enrichment and concentration methods, suggests that, if present, they are at very low titres.

SIGNIFICANCE AND IMPACT OF THE STUDY

Testing for Campylobacter phages as an indicator of Campylobacter spp. presence is not effective. The quantitative data for Campylobacter spp. will be useful for risk assessment purposes.