Campylobacter
ORGANISM
Genus Campylobacter
Species jejuni
GENERAL CONCEPTS
- The genus Campylobacter is a relatively recently discovered
important human pathogen. The reason for this is that the organisms are
microaerophilic, requiring low concentrations of oxygen only. Indeed,
Campylobacter infections occur more often than Salmonella
and Shigella E Coli
Coliforms diarrheas combined.
DISTINCTIVE PROPERTIES
- Campylobacters are Gram-negative, curved rods (the name derives
from the Greek "campylo", meaning curved). These organisms are microaerophilic
and motile.
- Campylobacters possess a typical Gram-negative cell wall containing
LPS endotoxin.
- There are approximately 50 heat-labile "K" (capsular) and "H" (flagellar)
antigens and 60 different heat-stable "O" (somatic) antigens associated with
different species of Campylobacter.
- These organisms are able to use amino acids and citric acid cycle
intermediates for growth. C. jejuni grows best at 42°.
PATHOGENESIS
- A relatively small inoculum is required to cause illness; as few as 800
bacteria can produce disease in healthy persons.
- Illness generally occurs following a 2-4 day incubation period when the
bacteria multiply in the intestine, reaching numbers similar to
Salmonella and Shigella infections
(106-109 per gram of feces). Symptoms resemble an acute
enteritis with fever, diarrhea, nausea and abdominal pain. The illness is
generally self-limiting but may last a week.
- C. jejuni appears to produce an enterotoxin similar to both the
cholera and Escherichia coli toxins.
HOST DEFENSES
- Host defense mechanisms that help to combat Campylobacter
infections are not well characterized but gastric acidity and secretory IgA
may be important.
EPIDEMIOLOGY
- The genus Campylobacter is widely distributed among cattle, sheep,
dogs, cats and other animals, existing as normal flora commensals.
- Human infection results from the ingestion of contaminated water, milk or
undercooked foods. Outbreaks resulting from ingestion of raw clams have been
reported.
DIAGNOSIS
Clinical : Clinical diagnosis is difficult since the symptomology is
non-specific.
Laboratory: Special methods are required for
isolation. Growth occurs in 5% O2, 10% CO2, 85%
N2 at 42°. A Gram stain of fecal material may reveal curved
("seagull" or "comma") shaped organisms.
CONTROL
Sanitary : As with other fecal-oral diseases, sanitary means of
control are most important. Proper disposal of feces, cooking foods, etc. can
prevent disease.
Immunological : None available.
Chemotherapeutic : Erythromycin or tetracycline can be used for
severe or prolonged illness.