TheCampylobacter-like genusArcobacteris frequently associated with
abortion and enteritis in cattle and pigs. Two species,Arcobacter butzleri
andA. cryaerophilus, have also been implicated in human infections
causing diarrhoea, bacteraemia and other extra-enteric infections.
7.4.2 The Organism and its Characteristics
Campylobacters are non-sporeforming, oxidase-positive, Gram-negative
rods. Cells are pleomorphic and may be 0.5–8mm in length and
0.2–0.5mm in width. Log-phase cells have a characteristic slender, curved
or spiral shape and one or more polar or amphitrichous flagella which
confer a rapid, darting motility and may be an important feature in
pathogenesis (Figure 7.2). As cultures age, spiral or curved bacilli are
replaced by round forms.
Campylobacters cannot ferment or oxidize sugars and are oxygen-
sensitive microaerophiles, growing best in an atmosphere containing
5–10% carbon dioxide and 3–5% oxygen.
AllCampylobacterspecies grow at 37 1 C;C. jejuniandC. colihave
optima at 42–45 1 C but cannot survive cooking or pasteurization tem-
peratures (D 55 2.5–6.6 min). They do not grow below 30 1 C and survive
poorly at room temperature. Although their viability declines during
chill or frozen storage, they may nevertheless persist under these condi-
tions for prolonged periods; survival has been recorded in milk and water
at 4 1 C after several weeks storage and in frozen poultry after several
Figure 7.2 Campylobacter jejuni
(Photo S. Boucher)
Chapter 7 193