Campylobacter jejuni/coli: Methodology of isolation and possible interfering factors in primary culture

Abstract

The prevalence of Campylobacter jejuni and Campylobacter coli was investigated in 64 samples of fresh retail chicken purchased from commercial slaughterhouses located in Brazil. Compylobacter spp. were isolated from 40 (62.5%) of 64 analyzed samples. The strains biotyped according to Lior were classified as C. jenjni biotypes I and II, and C. coli biotypes I and II. The efficiency of different procedures for recovering Campylobacter spp. from chicken carcasses was tested. The enrichment procedure was significantly less effective than direct plating (P<0.05), detecting 19 of 40 (47.5%) as opposed to 38 of 40 (95%) positive samples. Using direct plating the efficiency of Blaser's selective supplement was significantly more effective (P<0.05) than Skirrow's selective supplement. To verify which factors could be affecting Campylobacter spp. growth in enrichment broth, the pH was measured after incubation for 48 h at 42°C and lactobacilli, coliforms, and enterococci were enumerated. Most of the Campylobacter-negative samples presented high levels of indicator microorganisms, which may have hindered the recovery of Campylobacter spp. during the enrichment procedure.