A comparison of different culture methods for the recovery of Campylobacter species from pets.

Abstract

Five culture methods for the recovery of Campylobacter species (spp.) were evaluated on 361 rectal swabs collected from cats and dogs in Ireland. Speciation using PCR methods was performed on all isolates to assess the sensitivity of each culture method for isolation of Campylobacter spp., and to establish the prevalence of Campylobacter jejuni, C. coli, C. upsaliensis, C. lari and C. helveticus. Overall 163 of 361 (45.2%) samples were confirmed Campylobacter spp. positive. Direct plating onto modified charcoal cefoperazone deoxycholate agar (mCCDA) with cefoperazone, amphotericin and teicoplanin (CAT) selective supplement yielded a significantly higher prevalence of Campylobacter spp. (33.0%) than each of the other four methods (P < or = 0.05). This method was also the most sensitive method for isolation of C. upsaliensis compared with any of the other four methods used in the current study (P < or = 0.05). A direct plating method onto mCCDA agar with CCDA selective supplement and a filtration method onto blood agar after pre-enrichment in CAT supplemented broth yielded lower Campylobacter spp. prevalences of 19.7% and 17.5% respectively. A filtration method onto CAT agar and pre-enrichment in Preston broth before plating onto mCCDA agar were less sensitive for the isolation of Campylobacter spp. Speciation results of Campylobacter isolates revealed the majority of Campylobacter isolates were C. upsaliensis (50.0%) and C. jejuni (41.9%). A small number of isolates were C. coli (2.6%), C. lari (1.5%) and C. helveticus (1.1%). The overall detection of Campylobacter spp. in the 361 pets sampled was significantly increased by using a combination of isolation methods (P < or = 0.05), producing a more accurate determination of the prevalence of Campylobacter spp. in pets in Ireland and of the actual Campylobacter species. As the majority of Campylobacter spp. were recovered by direct plating onto mCCDA agar with CAT supplement, this method is the method of choice if only a single method is selected for isolation of the most common Campylobacter spp. detected in pets and humans.