 |
U.S. Food & Drug Administration Center for Food Safety & Applied Nutrition Foodborne Pathogenic Microorganisms and Natural Toxins Handbook |
 |
|
Campylobacter jejuni
| 1. Name
of the Organism: Campylobacter jejuni (formerly known as Campylobacter fetus subsp. jejuni) |
Campylobacter jejuni is a Gram-negative
slender, curved, and motile rod. It is a microaerophilic
organism, which means it has a requirement for reduced
levels of oxygen. It is relatively fragile, and sensitive
to environmental stresses (e.g., 21% oxygen, drying,
heating, disinfectants, acidic conditions). Because of
its microaerophilic characteristics the organism requires
3 to 5% oxygen and 2 to 10% carbon dioxide for optimal
growth conditions. This bacterium is now recognized as an
important enteric pathogen. Before 1972, when methods
were developed for its isolation from feces, it was
believed to be primarily an animal pathogen causing
abortion and enteritis in sheep and cattle. Surveys have
shown that C. jejuni is the leading cause of
bacterial diarrheal illness in the United States. It
causes more disease than Shigella
spp. and Salmonella
spp. combined. Although C. jejuni is not carried by healthy individuals in the United States or Europe, it is often isolated from healthy cattle, chickens, birds and even flies. It is sometimes present in non-chlorinated water sources such as streams and ponds. Because the pathogenic mechanisms of C. jejuni are still being studied, it is difficult to differentiate pathogenic from nonpathogenic strains. However, it appears that many of the chicken isolates are pathogens. |
| 2. Name of Disease: | Campylobacteriosis is the name of the illness caused by C. jejuni. It is also often known as campylobacter enteritis or gastroenteritis. |
| 3. Major Symptoms: | C. jejuni infection causes
diarrhea, which may be watery or sticky and can contain
blood (usually occult) and fecal leukocytes
(white cells). Other symptoms often present are fever,
abdominal pain, nausea, headache and muscle pain. The
illness usually occurs 2-5 days after ingestion of the
contaminated food or water. Illness generally lasts 7-10
days, but relapses are not uncommon (about 25% of cases).
Most infections are self-limiting and are not treated
with antibiotics. However, treatment with erythromycin
does reduce the length of time that infected individuals
shed the bacteria in their feces. The infective dose of C. jejuni is considered to be small. Human feeding studies suggest that about 400-500 bacteria may cause illness in some individuals, while in others, greater numbers are required. A conducted volunteer human feeding study suggests that host susceptibility also dictates infectious dose to some degree. The pathogenic mechanisms of C. jejuni are still not completely understood, but it does produce a heat-labile toxin that may cause diarrhea. C. jejuni may also be an invasive organism. |
| 4. Isolation Procedures: | C. jejuni is usually present in high numbers in the diarrheal stools of individuals, but isolation requires special antibiotic-containing media and a special microaerophilic atmosphere (5% oxygen). However, most clinical laboratories are equipped to isolate Campylobacter spp. if requested. |
| 5. Associated Foods: | C. jejuni frequently contaminates raw chicken. Surveys show that 20 to 100% of retail chickens are contaminated. This is not overly surprising since many healthy chickens carry these bacteria in their intestinal tracts. Raw milk is also a source of infections. The bacteria are often carried by healthy cattle and by flies on farms. Non-chlorinated water may also be a source of infections. However, properly cooking chicken, pasteurizing milk, and chlorinating drinking water will kill the bacteria. |
| 6. Frequency of the Disease: | C. jejuni is the leading cause of bacterial diarrhea in the U.S. There are probably numbers of cases in excess of the estimated cases of salmonellosis (2- to 4,000,000/year). |
| 7. Complications: | Complications are relatively rare, but
infections have been associated with reactive arthritis, hemolytic
uremic syndrome, and following septicemia, infections
of nearly any organ. The estimated case/fatality ratio
for all C. jejuni infections is 0.1, meaning one
death per 1,000 cases. Fatalities are rare in healthy
individuals and usually occur in cancer patients or in
the otherwise debilitated. Only 20 reported cases of
septic abortion induced by C. jejuni have been
recorded in the literature. Meningitis, recurrent colitis, acute cholecystitis and Guillain-Barre syndrome are very rare complications. |
| 8. Target Populations: | Although anyone can have a C. jejuni infection, children under 5 years and young adults (15-29) are more frequently afflicted than other age groups. Reactive arthritis, a rare complication of these infections, is strongly associated with people who have the human lymphocyte antigen B27 (HLA-B27). |
| 9. Recovery from Foods: | Isolation of C. jejuni from food is difficult because the bacteria are usually present in very low numbers (unlike the case of diarrheal stools in which 10/6 bacteria/gram is not unusual). The methods require an enrichment broth containing antibiotics, special antibiotic-containing plates and a microaerophilic atmosphere generally a microaerophilic atmosphere with 5% oxygen and an elevated concentration of carbon dioxide (10%). Isolation can take several days to a week. |
| 10. Selected Outbreaks: | Usually outbreaks are small (less than
50 people), but in Bennington, VT a large outbreak
involving about 2,000 people occurred while the town was
temporarily using an non-chlorinated water source as a
water supply. Several small outbreaks have been reported
among children who were taken on a class trip to a dairy
and given raw milk to drink. An outbreak was also
associated with consumption of raw clams. However, a
survey showed that about 50% of infections are associated
with either eating inadequately cooked or recontaminated
chicken meat or handling chickens. It is the leading
bacterial cause of sporadic (non-clustered cases)
diarrheal disease in the U.S. In April, 1986, an elementary school child was cultured for bacterial pathogens (due to bloody diarrhea), and C. jejuni was isolated. Food consumption/gastrointestinal illness questionnaires were administered to other students and faculty at the school. In all, 32 of 172 students reported symptoms of diarrhea (100%), cramps (80%), nausea (51%), fever (29%), vomiting (26%), and bloody stools (14%). The food questionnaire clearly implicated milk as the common source, and a dose/response was evident (those drinking more milk were more likely to be ill). Investigation of the dairy supplying the milk showed that they vat pasteurized the milk at 135°F for 25 minutes rather than the required 145°F for 30 minutes. The dairy processed surplus raw milk for the school, and this milk had a high somatic cell count. Cows from the herd supplying the dairy had C. jejuni in their feces. This outbreak points out the variation in symptoms which may occur with campylobacteriosis and the absolute need to adhere to pasteurization time/temperature standards. Although other Campylobacter spp. have been implicated in human gastroenteritis (e.g. C. laridis, C. hyointestinalis), it is believed that 99% of the cases are caused by C. jejuni. |
| Information regarding an outbreak of
Campylobacter in New Zealand is found in this MMWR
40(7):1991 Feb 22. |
|
| For more information on recent outbreaks see the Morbidity and Mortality Weekly Reports from CDC. | |
| 11. Education: | The Food Safety Inspection Service of the U.S. Department of Agriculture has produced a background document on Campylobacter. |
| 12. Other Resources: | A Loci index for genome Campylobacter jejuni is available from GenBank. |
mow@cfsan.fda.gov
January 1992 with periodic updates
Hypertext last updated by mow/xxz/ear 2000-MAR-08