Comparison of media and filtration procedures for qualitative recovery of thermotolerant Campylobacter spp. from naturally contaminated surface water

Abstract

Different media and filtration procedures were compared for efficiency in recovering thermotolerant campylobacters from three naturally contaminated water sources representing different turbidities and levels of contamination. Three selective enrichment broths were evaluated. Regardless of the kind of broth employed, enrichment did not significantly enhance recovery over that produced by direct plating onto both Skirrow's agar and colistin-amphotericin-keflin (CAK) agar. However, enrichment was clearly advantageous when Skirrow's agar was used as the sole plating medium. Of the four filtration procedures compared, the highest recovery was obtained with 0.45 μm Millipore membrane filters. Subsequent filtration through a 0.22 μm membrane did not increase the yield. Of the three plating media evaluated, the best overall recovery was obtained with Preston agar, followed by CAK agar, whereas Skirrow's medium was inferior. For all three agar media, incubation for 48 h greatly increased the yield as compared with 24 h incubation. We could not demonstrate any statistically significant differences between the plating media as regards their relative efficiency in isolating different Campylobacter species.