670 Modern Food Microbiology
Peak isolations from individually caged hens occurred in October and late April–early May.
39 In the
latter study, 8.1% of the hens were chronic excreters of the organism, whereas 33% were negative even
though they were likely exposed. The most probable source of C. jejuni to a duck processing farm
was found to be rat and mice droppings, with 86.7% of the former being positive for this species.
67
The consensus seems to be that this organism is not transmitted through the hatchery, but instead to
broiler chicks by vermin as noted. The cecum is the principal site of colonization, and the organisms
generally are not pathogenic to adult birds.
The numbers of C. jejuni on some poultry products range from log 2.00 to 4.26/g. Once this organism
is established in a chicken house, most of the flock becomes infected over time. One study revealed
that the organism appeared in all chicken inhabitants within a week once it was found among any
of the inhabitants.
117 In addition to poultry, the other primary source of this organism is raw milk.
Because the organism exists in cow feces, it is not surprising that it may be found in raw milk, and the
degree of contamination would be expected to vary depending on milking procedures. In a survey of
108 samples from bulk tanks of raw milk in Wisconsin, only 1 was positive for C. jejuni, whereas the
feces of 64% of the cows in a grade A herd were positive.
40 In the Netherlands, 22% of 904 cow fecal
and 4.5% of 904 raw milk samples contained C. jejuni.
11
The significance of cross-contamination as a source of this organism to humans is illustrated by the
following outbreak: There were 14 cases of Campylobacter enteritis in Oklahoma traced to lettuce and
lasagna.
26 The foods were prepared in a small area where raw chicken was cut, and in all probability,
the vehicle foods became contaminated. See Chapters 4 and 9 for numbers of campylobacters in
various foods.
Virulence Properties
At least some strains of C. jejuni produce a heat-labile enterotoxin (CJT) that shares some common
properties with the enterotoxins of V. cholerae (CT) and E. coli (LT). CJT increases cAMP levels,
induces changes in CHO cells, and induces fluid accumulation in rat ileal loops.
108 Maximal production
of CJT in a special medium was achieved at 42
◦ C in 24 hours, and the amount produced was enhanced
by polymyxin.
72 The quantities produced by strains varied widely from none to about 50 ng/ml CJT
protein. The amount of toxin was doubled as measured by Y-1 adrenal cell assay when cells were
first exposed to lincomycin and then polymyxin.
83 CJT is neutralized by CT and E. coli LT antisera,
indicating immunological homology with these two enterotoxins.
72 The C. jejuni LT appears to share
the same cell receptors as CT and E. coli LT, and it contains a B subunit immunologically related to
the B subunits of CT and LT of E. coli.
73 Also, a cytotoxin is produced that is active against Vero and
HeLa cells. The enterotoxin and the cytotoxin induce fluid accumulation in rat jejunal loops but not in
mice, pigs, or calves. Partially purified enterotoxin contained three fractions with molecular weights
of 68, 54, and 43 kDa.
61 Of 202 strains of C. jejuni and C. coli recovered from humans with enteritis
and from healthy laying hens, 34% and 22% of the C. jejuni and C. coli strains, respectively, produced
enterotoxin as determined by CHO assay.
78
From a comparison of poultry and human isolates of Campylobacter jejuni, invasiveness or Vero cell
toxicity was higher for human than for poultry isolates.
89 Invasiveness was associated with biotypes
1 and 2 while cell toxicity (with CHO and INT-407 cells) was associated with biotypes 3 and 4.
C. jejuni enteritis appears to be caused in part by the invasive abilities of the organism. Evidence for
this comes from the nature of the clinical symptoms, the rapid development of high agglutinin titers
after infection, recovery of the organism from peripheral blood during the acute phase of the disease,
Peak isolations from individually caged hens occurred in October and late April–early May.
39 In the
latter study, 8.1% of the hens were chronic excreters of the organism, whereas 33% were negative even
though they were likely exposed. The most probable source of C. jejuni to a duck processing farm
was found to be rat and mice droppings, with 86.7% of the former being positive for this species.
67
The consensus seems to be that this organism is not transmitted through the hatchery, but instead to
broiler chicks by vermin as noted. The cecum is the principal site of colonization, and the organisms
generally are not pathogenic to adult birds.
The numbers of C. jejuni on some poultry products range from log 2.00 to 4.26/g. Once this organism
is established in a chicken house, most of the flock becomes infected over time. One study revealed
that the organism appeared in all chicken inhabitants within a week once it was found among any
of the inhabitants.
117 In addition to poultry, the other primary source of this organism is raw milk.
Because the organism exists in cow feces, it is not surprising that it may be found in raw milk, and the
degree of contamination would be expected to vary depending on milking procedures. In a survey of
108 samples from bulk tanks of raw milk in Wisconsin, only 1 was positive for C. jejuni, whereas the
feces of 64% of the cows in a grade A herd were positive.
40 In the Netherlands, 22% of 904 cow fecal
and 4.5% of 904 raw milk samples contained C. jejuni.
11
The significance of cross-contamination as a source of this organism to humans is illustrated by the
following outbreak: There were 14 cases of Campylobacter enteritis in Oklahoma traced to lettuce and
lasagna.
26 The foods were prepared in a small area where raw chicken was cut, and in all probability,
the vehicle foods became contaminated. See Chapters 4 and 9 for numbers of campylobacters in
various foods.
Virulence Properties
At least some strains of C. jejuni produce a heat-labile enterotoxin (CJT) that shares some common
properties with the enterotoxins of V. cholerae (CT) and E. coli (LT). CJT increases cAMP levels,
induces changes in CHO cells, and induces fluid accumulation in rat ileal loops.
108 Maximal production
of CJT in a special medium was achieved at 42
◦ C in 24 hours, and the amount produced was enhanced
by polymyxin.
72 The quantities produced by strains varied widely from none to about 50 ng/ml CJT
protein. The amount of toxin was doubled as measured by Y-1 adrenal cell assay when cells were
first exposed to lincomycin and then polymyxin.
83 CJT is neutralized by CT and E. coli LT antisera,
indicating immunological homology with these two enterotoxins.
72 The C. jejuni LT appears to share
the same cell receptors as CT and E. coli LT, and it contains a B subunit immunologically related to
the B subunits of CT and LT of E. coli.
73 Also, a cytotoxin is produced that is active against Vero and
HeLa cells. The enterotoxin and the cytotoxin induce fluid accumulation in rat jejunal loops but not in
mice, pigs, or calves. Partially purified enterotoxin contained three fractions with molecular weights
of 68, 54, and 43 kDa.
61 Of 202 strains of C. jejuni and C. coli recovered from humans with enteritis
and from healthy laying hens, 34% and 22% of the C. jejuni and C. coli strains, respectively, produced
enterotoxin as determined by CHO assay.
78
From a comparison of poultry and human isolates of Campylobacter jejuni, invasiveness or Vero cell
toxicity was higher for human than for poultry isolates.
89 Invasiveness was associated with biotypes
1 and 2 while cell toxicity (with CHO and INT-407 cells) was associated with biotypes 3 and 4.
C. jejuni enteritis appears to be caused in part by the invasive abilities of the organism. Evidence for
this comes from the nature of the clinical symptoms, the rapid development of high agglutinin titers
after infection, recovery of the organism from peripheral blood during the acute phase of the disease,