Prevalence of 11 pathogenic genes of Campylobacter jejuni by PCR in strains isolated from humans, poultry meat and broiler and bovine faeces

Abstract

Although many genes related to the pathogenicity of Campylobacter jejuni have been reported, the relationships between these genes and the sources of strains are not clear. In this study, the presence of 11 pathogenic genes responsible for the expression of adherence, invasion, colonization and cytotoxin production was examined in 111 C. jejuni isolated from human clinical samples, poultry meat, broiler faeces and bovine faeces. For most of the pathogenic genes, no difference in their presence in C. jejuni was found among the sources, but, for racR, wlaN and virB11, there were some variations among sources. The racR gene was present at rates of 98·2 (human clinical samples), 90·5 (poultry meat), 85·7 (broiler faeces) and 76·7 % (bovine faeces). Detection rates for the wlaN gene were 25·0, 23·8, 4·7 and 7·7 % and those for the virB11 gene were 10·7, 9·5, 9·5 and 15·4 % in human clinical samples, poultry meat, broiler faeces and bovine faeces, respectively. One hundred and seven of 111 strains (96·4 %) carried from eight to 10 of the pathogenic genes. These data did not show remarkable differences in the presence of pathogenic genes carried by C. jejuni from various sources. IntroductionCampylobacter jejuni is one of the most common causes of bacterial enteritis. Campylobacteriosis is mainly a foodborne infection, and poultry products may play an important role in transmission to humans (Park, 2002). C. jejuni contamination of poultry meat during processing has been reported (Kazwala et al., 1990;Chuma et al., 1994Chuma et al., , 1997Berrang et al., 2001;Hartnett et al., 2001). Adherence, invasion and cytotoxin production appear to be possible virulence factors. The clinical and epidemiological characteristics of the disease provide clues to the molecular mechanisms that play a role in C. jejuni infection. Recently, some genes have been recognized as responsible for the expression of pathogenicity. In this study, flaA (Nuijten et al., MethodsBacterial strains and growth conditions. One hundred and eleven strains in total were tested in this study, including 56 isolates from human clinical samples, 21 from poultry meat, 21 from broiler faeces and 13 from bovine faeces. All strains were incubated on Müller-Hinton agar (Oxoid) at 42 8C under microaerobic conditions (85 % N 2 , 5 % O 2 , 10 % CO 2 ) for 24 h.Preparation of DNA. Template DNAs for PCR were extracted by the conventional boiling method. Fresh cultures of C. jejuni were suspended in 300 ìl TE buffer and the suspensions were boiled at 95 8C for 10 min. After centrifugation at 15 000 r.p.m. for 2 min, the supernatants were stored at À20 8C and used as template DNA.PCR primer design and amplification.

Virulence genes and cytokine profile in systemic murineCampylobacter coliinfection

“…In contrast, several studies have shown wide variations for the presence of virB11, which was not found in C. jejuni and C. coli isolates from poultry faeces, 18 although it was identified in 4% to 15% of isolates tested from poultry meat, pig and cattle, 31,32,36 and in 10% to 17% of human clinical samples. 31,38 However, the prevalence of the plasmid pVir appears to be similar among poultry and human isolates. 17,31,38 The production of the pVir plasmid genes in the C. coli 26536 clinical isolate used in the present study thus indicates the possibility of severe invasive infection.…”

“…30,31,37 The cadF gene is probably conserved among Campylobacter spp isolates, 18 regardless of their origin or species, as is the case also in the C. coli 26536 isolate used here. In contrast, several studies have shown wide variations for the presence of virB11, which was not found in C. jejuni and C. coli isolates from poultry faeces, 18 although it was identified in 4% to 15% of isolates tested from poultry meat, pig and cattle, 31,32,36 and in 10% to 17% of human clinical samples. 31,38 However, the prevalence of the plasmid pVir appears to be similar among poultry and human isolates.…”

“…Analysis of the cadF gene has revealed its high prevalence (i.e., 100%) among Campylobacter spp. isolates derived from poultry carcasses, broiler faeces, bovine faeces, retail raw meat, pig and cattle, 18,[30][31][32]36 and also among isolates of human origin. 30,31,37 The cadF gene is probably conserved among Campylobacter spp isolates, 18 regardless of their origin or species, as is the case also in the C. coli 26536 isolate used here.…”

“…isolates derived from poultry carcasses, broiler faeces, bovine faeces, retail raw meat, pig and cattle, 18,[30][31][32]36 and also among isolates of human origin. 30,31,37 The cadF gene is probably conserved among Campylobacter spp isolates, 18 regardless of their origin or species, as is the case also in the C. coli 26536 isolate used here. In contrast, several studies have shown wide variations for the presence of virB11, which was not found in C. jejuni and C. coli isolates from poultry faeces, 18 although it was identified in 4% to 15% of isolates tested from poultry meat, pig and cattle, 31,32,36 and in 10% to 17% of human clinical samples.…”

“…6,7 Indeed, several potential virulence factors have been identified 11,[13][14][15]23 that show different prevalence according to the human, animal or environmental sources of the Campylobacter spp strain. 18,[30][31][32] One of these is the cadF gene, which encodes a protein belonging to the group of outer-membrane proteins that facilitates the binding of Campylobacter spp. in the host cells, 33 as was confirmed by Campylobacter spp colonisation using a chicken model.…”