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Flashcards in PHEW Deck (14)
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Isolation of Campylobacter is carried out on which kind of agar and under what conditions?

Blood-based agar (eg CCDA) under reduced oxygen tension


Which agar is frequently used to identify enterobacteriacae and why?

MacConkey agar- Bile salts inhibit non-enterics


Out of E.coli and salmonella, which ferments lactose to form pink colonies on agar gel? (colour change from yellow to pink)

E. coli


What family of bacteria does salmonella fall into?



Which antigens allow E.coli to attach to the urethra/bladder and cause urinary tract injections?

K antigens


What are the clinical signs of E.coli?

Diarrhoea, septicaemia,


How does E.coli attach?

Via pili and fimbria


Which toxins cause entero-haemorrhagic E.coli, by damaging blood vessels?

Shiga-like toxins
Also act on kidneys causing haemolytic uremic syndrome


Urinary tract infections are associated with which strains of E.coli?

Capsular strains


Where is the main site of colonisation of E.coli?

Distal rectum


How are humans infected with salmonella?

Via meat or eggs from infected animals or foodstuffs contaminated with faeces from infected animals
Person-to-person transmission in families


How long do salmonella symptoms last?

4-7 days


Human campylobacteriosis results in what side effect?

Painful diarrhoea which is often profuse but self-limiting


Why is the broiler chicken the main source of campylobacter?

Core temperature of 41-42°C suits the thermophilic bug
Low oxygen tension in gut suits microaerophiles
High levels of growth supported in caeca (up to 1010 CFU per g)
High levels of shedding in faecal and caecal droppings coupled with coprophagic behaviour lead to rapid spread through houses
Campy persists well in the caeca and birds can be infected by a succession of different strains
Feed withdrawal and transport lead to stress and increased shedding
Automated plucking, evisceration and use of scald and wash tanks lead to frequent cross-contamination on lines
Rapidly growing modern broiler breeds have relatively poor immune systems and may be susceptible to an increasingly nasty bug