Prevalence and molecular identification of Campylobacter species isolates from poultry and humans in Sokoto, Nigeria

Abstract

Prevalence and molecular identification of Campylobacter species isolates from poultry and humans were conducted using culture, biochemical reaction and Polymerase Chain Reaction (PCR) techniques. A total of 798 (506 poultry and 292 human) samples were identified biochemically, out of which 312(39.1%) were positive for Campylobacter species. Campylobacter jejuni, C. coli and C. lari had 38 (23.8%) out of 160, 63(39.4%) out of 160, 59(36.9%) out of 160 prevalence rates, respectively in humans while 29(19.1%) out of 152, 79(52.0%) out of 152 and 44(28.9%) out of 152 were the rates for the species in the same order in poultry. Campylobacter isolates were kept at -20oC in 15% glycerol and 85% tryptone broth until used while some were identified 24hrs post isolation. Single and multiplex PCR were used to confirm the genus Campylobacter and three Campylobacter species, respectively. All the 130(100 stored and 30 fresh) isolates were members of the genus Campylobacter. The single PCR band view of stored isolates also revealed other bands in addition to 439 bp which is specific for the genus Campylobacter, while the fresh isolates had distinct bands at 439bp only. Multiplex PCR revealed 2(6.7%) out of 30 were positive for stored isolates out of 30, 1(50%) each for C. jejuni and C. Coli. However, 1 of the stored isolate was positive for both spp. On the other hand, 6(20.0%) of out 60 fresh isolates were positive, with 5(83.3%) and 1(16.7%) for C. jejuni and C. coli, respectively. The possibilities of improper identification using conventional method have been revealed in the study. PCR can identify Campylobacter species more accurately than biochemical method, though storage of isolates, integrity of extracted DNA and PCR conditions can affect result. However, the use of both methods should be encouraged in regular and effective surveillance of Campylobacter species in poultry and humans.

Keywords: Campylobacter species, Humans, Molecular identification , Nigeria, Prevalence, Poultry, Sokoto