Campylobacter

Dr. Abdulaziz Bamarouf

Learning Objectives

• Describe the general characteristics of the genus Campylobacter

• List the causative agent, virulence factors, epidemiology, modes of transmission, site of infection, methods of treatment and prevention of Campylobacter infections

• Discuss laboratory diagnosis of Campylobacter infections

Main species

• Campylobacter (meaning “twisted” bacteria) species include:

• C. jejuni

• C. coli

• C. lari

General Characteristics

• Gram-negative, curved, spiral-shaped, S-shaped rods

• Non-sporing

• Motile (polar flagella)

• Oxidase positive

• Microaerophilic (grow best at 5% O2, 10% CO2, 85% N2) at 42 C

Virulence Factors

• Flagella

• Adhesions

• Endotoxin & Enterotoxin

• Ability to penetrate cells (invasive)

Epidemiology

• Present in animal species (chicken, cattle, goats, sheep, cats, dogs …)

• In developed countries, they cause more cases of diarrhoea than foodborne Salmonella

• Zoonotic infection (a disease transmitted to humans from animals or animal products)

• Although C. jejuni enteritis occurs throughout the year, the highest isolation rates occur in summer, as with other enteric pathogens.

• Campylobacter infections are generally mild, but can be fatal among very young children, young adults and immunosuppressed individuals.

Comparison of the epidemiology of C. jejuni and H. pylori by seasonal distribution by month (panel A)

and by age (panel B)

Transmission• Infection is acquired by ingestion: Consumption of contaminated food, water,

unpasteurized milk and undercooked meat

• Most often, carcasses or meat are contaminated by Campylobacter from faeces during slaughtering. In animals, Campylobacter seldom causes disease

-Direct contact with infected animals and their products

• Cause: enteritis

• Site: small and large intestines

• Action: mucosal invasion & toxin production

• Symptoms: diarrhea frequently with blood in the faeces

• Could lead to Bacteremia (presence of bacteria in the blood)

Laboratory Diagnosis• Specimen: Stool (contain mucus, pus and

blood), rectal swab, blood

• Culture: on selective media containing: -Charcoal: to remove oxygen radicals -Antibiotics: to inhibit other bacteria and enriched with blood -Selective media: 1) Skirrow's-blood agar 2) Campy-blood agar

-Incubation: microaerophilic )grow best at 5% O2, 10% CO2, 85% N2) at 42 C for 48 hours.

-Look for mucoid, flat colonies like spreading oil droplets

• Biochemical identification: -Gram-negative, curved rods -Oxidase positive -Catalase positive

• Antimicrobial sensitivity testing

Treatment

-Usually self-limiting

-Patient require only fluids and electrolytes replacement and rehydration

-Antibiotics in case of septicemia: erythromycin

Prevention

-Proper preparation of food

-Consumption of pasteurized milk

-Prevention of contaminated water supply

-Campylobacter species can be killed by heat and thoroughly cooking food