Foodborne Gastroenteritis Caused by Vibrio, Yersinia, and Campylobacter Species 669
The latter differs from Campylobacter coli in being able to hydrolyze hippurate. The campylobacters
are more closely related to the genus Arcobacter than any other group. C. jejuni has the distinction of
being the first foodborne pathogen whose genome was sequenced (it contains 1.64 million bases).
Prior to the 1970s, the campylobacters were known primarily to veterinary microbiologists as
organisms that caused spontaneous abortions in cattle and sheep and as the cause of other animal
pathologies. They were once classified as Vibrio spp.
C. jejuni is a slender, spirally curved rod that possesses a single polar flagellum at one or both
ends of the cell. It is oxidase and catalase positive and will not grow in the presence of 3.5% NaCl
or at 25
◦ C. It is microaerophilic, requiring small amounts of oxygen (3–6%) for growth. Using an
autobioluminescent strain of C. jejuni, its minimum, optimum, and maximum growth temperatures on
solid media in a gradient-plate format were 30, 40, and 45
◦ C.
68 At the optimum growth temperature
of 40
◦ C, this strain grew well at pH 5.5–8.0, and in the presence of up to 1.75% NaCl. Growth is
actually inhibited in 21% oxygen. Carbon dioxide (about 10%) is required for good growth. When
C. jejuni was inoculated into vacuum-packaged processed turkey meat, cell numbers decreased, but
some remained viable for 28 days at 4
◦ C.
105 Its metabolism is respiratory. In addition to C. jejuni,
C. coli, C. intestinalis, and several other Campylobacter species are known to cause diarrhea in humans,
but C. jejuni is by far the most important.
Because of their small cell size, they can be separated from most other Gram-negative bacteria by
use of a 0.65-µm filter. C. jejuni is heat sensitive, with D 55 ◦ C for a composite of equal numbers of
five strains being 1.09 minutes in peptone and 2.25 minutes in ground, autoclaved chicken.
14 With
internal heating of ground beef to 70
◦ C, 10
7 cells/g could not be detected after about 10 minutes.
120
It appears to be sensitive to freezing, with about 10
5 cells per chicken carcass being greatly reduced
or eliminated at -18
◦ C, and for artificially contaminated hamburger meat, the numbers were reduced
by 1 log cycle over a 7-day period.
47
Distribution
Unlike Y. enterocolitica and V. parahaemolyticus, C. jejuni is not an environmental organism but
rather is one that is associated with warm-blooded animals. A large percentage of all major meat
animals have been shown to contain these organisms in their feces, with poultry being prominent.
Its prevalence in fecal samples often ranges from around 30% to 100%. Reports on isolations by
various investigators have been summarized by Blaser,
15 and the specimens and percentages positive
for C. jejuni are as follows: chicken intestinal contents (39–83), swine feces (66–87), sheep feces (up
to 73), swine intestinal contents (61), sheep carcasses (24), swine carcasses (22), eviscerated chicken
(72–80), and eviscerated turkey (94).
In a 5-year longitudinal study on a small rearing farm in southern England in 1989–1994, 12,233
broilers were examined and 27% were positive for C. jejuni.
102 Of 251 shed flocks, 35.5% carried
C. jejuni, but only 9.2% had the organism in successive flocks. Overall, there was a low level of
transmission between flocks. A common source was suggested via vertical transmission rather than
hatchery or transportation sources because of the lack of high diversity of types.
102 The ecology and
prevalence of campylobacters in other fresh foods and the environment have been reviewed.
91
Fecal specimens from humans with diarrhea yield C. jejuni, and it may be the single most common
cause of acute bacterial diarrhea in humans. From 8,097 specimens submitted to eight hospital laboratories over a 15-month period in different parts of the United States, this organism was recovered
from 4.6%, salmonellae from 2.3%, and shigellae from 1%.
16 The peak isolations for C. jejuni were
in the age group 10–29 years. Peak isolations occur during the summer months, and it has been noted
that 3–14% of diarrheal patients in developed countries yield stool specimens that contain C. jejuni.
15
The latter differs from Campylobacter coli in being able to hydrolyze hippurate. The campylobacters
are more closely related to the genus Arcobacter than any other group. C. jejuni has the distinction of
being the first foodborne pathogen whose genome was sequenced (it contains 1.64 million bases).
Prior to the 1970s, the campylobacters were known primarily to veterinary microbiologists as
organisms that caused spontaneous abortions in cattle and sheep and as the cause of other animal
pathologies. They were once classified as Vibrio spp.
C. jejuni is a slender, spirally curved rod that possesses a single polar flagellum at one or both
ends of the cell. It is oxidase and catalase positive and will not grow in the presence of 3.5% NaCl
or at 25
◦ C. It is microaerophilic, requiring small amounts of oxygen (3–6%) for growth. Using an
autobioluminescent strain of C. jejuni, its minimum, optimum, and maximum growth temperatures on
solid media in a gradient-plate format were 30, 40, and 45
◦ C.
68 At the optimum growth temperature
of 40
◦ C, this strain grew well at pH 5.5–8.0, and in the presence of up to 1.75% NaCl. Growth is
actually inhibited in 21% oxygen. Carbon dioxide (about 10%) is required for good growth. When
C. jejuni was inoculated into vacuum-packaged processed turkey meat, cell numbers decreased, but
some remained viable for 28 days at 4
◦ C.
105 Its metabolism is respiratory. In addition to C. jejuni,
C. coli, C. intestinalis, and several other Campylobacter species are known to cause diarrhea in humans,
but C. jejuni is by far the most important.
Because of their small cell size, they can be separated from most other Gram-negative bacteria by
use of a 0.65-µm filter. C. jejuni is heat sensitive, with D 55 ◦ C for a composite of equal numbers of
five strains being 1.09 minutes in peptone and 2.25 minutes in ground, autoclaved chicken.
14 With
internal heating of ground beef to 70
◦ C, 10
7 cells/g could not be detected after about 10 minutes.
120
It appears to be sensitive to freezing, with about 10
5 cells per chicken carcass being greatly reduced
or eliminated at -18
◦ C, and for artificially contaminated hamburger meat, the numbers were reduced
by 1 log cycle over a 7-day period.
47
Distribution
Unlike Y. enterocolitica and V. parahaemolyticus, C. jejuni is not an environmental organism but
rather is one that is associated with warm-blooded animals. A large percentage of all major meat
animals have been shown to contain these organisms in their feces, with poultry being prominent.
Its prevalence in fecal samples often ranges from around 30% to 100%. Reports on isolations by
various investigators have been summarized by Blaser,
15 and the specimens and percentages positive
for C. jejuni are as follows: chicken intestinal contents (39–83), swine feces (66–87), sheep feces (up
to 73), swine intestinal contents (61), sheep carcasses (24), swine carcasses (22), eviscerated chicken
(72–80), and eviscerated turkey (94).
In a 5-year longitudinal study on a small rearing farm in southern England in 1989–1994, 12,233
broilers were examined and 27% were positive for C. jejuni.
102 Of 251 shed flocks, 35.5% carried
C. jejuni, but only 9.2% had the organism in successive flocks. Overall, there was a low level of
transmission between flocks. A common source was suggested via vertical transmission rather than
hatchery or transportation sources because of the lack of high diversity of types.
102 The ecology and
prevalence of campylobacters in other fresh foods and the environment have been reviewed.
91
Fecal specimens from humans with diarrhea yield C. jejuni, and it may be the single most common
cause of acute bacterial diarrhea in humans. From 8,097 specimens submitted to eight hospital laboratories over a 15-month period in different parts of the United States, this organism was recovered
from 4.6%, salmonellae from 2.3%, and shigellae from 1%.
16 The peak isolations for C. jejuni were
in the age group 10–29 years. Peak isolations occur during the summer months, and it has been noted
that 3–14% of diarrheal patients in developed countries yield stool specimens that contain C. jejuni.
15