TABLE 4.

Effect of age of protozoa during coculture on Campylobacter disinfection resistancea

Protozoan age (days)LocationAvg Campylobacter count (CFU/ml) ± SD
C. coli NCTC 11366C. jejuni NCTC 11351C. jejuni (poultry isolate)
T. pyriformis
    3Internal(3.52 × 103) ± 285(4.28 × 103) ± 730(5.77 × 103) ± 999
    3External0 ± 0132 ± 18313 ± 22
    6Internal(11.21 × 102) ± 134(3.25 × 103) ± 164(4.56 × 103) ± 644
    6External5 ± 316 ± 1033 ± 10
    9Internal0 ± 00 ± 00 ± 0
    9External0 ± 00 ± 00 ± 0
A. castellanii
    3Internal269 ± 33326 ± 32375 ± 16
    3External1 ± 13 ± 15 ± 1
    6Internal113 ± 12154 ± 24172 ± 20
    6External0 ± 00 ± 00 ± 0
    9Internal0 ± 00 ± 00 ± 0
    9External0 ± 00 ± 00 ± 0
  • a T. pyriformis (CCAP 1630/14A) and A. castellanii (CCAP 1501/10) were each grown for 3, 6, and 9 days before being cocultured for 3 h at 25°C (1:1 ratio) with Campylobacter spp. in PAS solution. A 1:1,000 dilution of Virudine (1-min contact time) was then used to kill planktonic C. jejuni, followed by neutralization using STS, gravity filtration (0.8-μm pore size), rinsing and resuspension in PAS, sonication (10 s at 40 W), and counts of viable Campylobacter. Results are presented as the average (performed in quadruplicate) numbers of viable Campylobacter recovered ml of PAS.