Campylobacter Characteristics and Pathogenesis

Campylobacter

• Characteristics: S-shaped, spiral-curved, gram-negative, motile with polar flagella, microaerophilic.
• Campylobacter fetus:
  • Two subspecies: fetus and venerealis.
  • Both subspecies possess a surface protein capsule, which is key for virulence.
  • venerealis: Found in the genital tract of cattle and causes bovine genital campylobacteriosis, venereally transmitted.
  • fetus: Found in the intestines of cattle and sheep, ingested by animals.
• Campylobacter jejuni: Common commensal in intestines of various animals.
  • Causes diarrhea and enterocolitis in various animals, more severe in younger animals.
  • Virulence factors: adhesin, endotoxin, cytotoxin, enterotoxin.
  • Pathogenesis: Invasivness due to flagella and adhesin, survival in phagosomes, enterotoxin induces fluid loss in intestines, leading to diarrhea, cytotoxin causes tissue destruction.
• Public Health Significance of Campylobacter:
  • C. fetus subsp. fetus: Infrequently causes human infections (bacteremia, arthritis, endocarditis, etc.)
  • Opportunistic pathogens: Several other species of Campylobacter can occasionally infect humans, causing wound infections, diarrhea, proctitis, etc.
  • C. jejuni: Most frequent pathogen in human gastroenteritis, transmitted by contaminated food, water, and animal feces.

Helicobacter

• Characteristics: Gram-negative, spiral and curved, motile with multiple flagella, microaerophilic.
• Helicobacter pylori: Most common species in humans, carried in stomach of many animals.
  • Mechanism It lives beneath the stomach's mucus layer.
  • Pathology: It breaks down urea, raising the pH, contributing to its survival and causing gastritis, ulcers, and potentially gastric cancer.
• Other Helicobacter species: Can cause gastritis in dogs and cats.
• Helicobacter pylori transmission: Main routes are fecal-oral and oral-oral.
  • Pathogenicity in animals: Causes gastritis, ulcers, and potentially gastric adenocarcinoma in humans.
  • Clinical signs in dogs and cats: Vomiting, regurgitation, abdominal pain, fever, diarrhea, anorexia, weight loss, and poor condition.
• Diagnosis of helicobacter:
  • Isolation is complex.
  • Identification relies on demonstration of helical organisms and gastritis.
  • Urease is supportive, and scrapings of the gastric mucosa are examined microscopically for motile, helical-shaped organisms.

Campylobacter

• Characteristics: S-shaped, spirally curved, gram-negative, pleomorphic rods. Motile by a single polar flagellum at one or both ends. Microaerophilic (3%-5% CO2), aerobic or anaerobic, and oxidase-positive.
• Species: Eighteen species are recognized, but only two are pathogenic to animals: Campylobacter fetus (with two subspecies) and Campylobacter jejuni.
• Nonpathogenic Species: Generally nonpathogenic Campylobacter spp are found on the mucous membrane of the genital and intestinal tracts.
• C. fetus subsp. fetus: Occurs in the intestines of cattle and sheep, and the genital tract of infected sheep and cattle. The mode of infection is ingestion, directly or via fomites.
• C. fetus subsp. fetus: Infection After ingestion there is hematogenous spread with infection of the uterine mucosa. Can cause abortion in cattle (sporadic) and sheep (multiple).
• C. fetus subsp. venerealis: Causes bovine genital campylobacteriosis. The organism can be found in the preputial cavity of the asymptomatic bull and the genital tracts of cows and heifers.
• C. fetus subsp. venerealis: Infection The mode of infection is venereal, organisms are present in the semen of infected bulls.

Campylobacter – Public Health Significance

• C. fetus subsp. fetus causes infrequent human infections.
• Infections include: bacteremia, septic arthritis, endocarditis, septic abortions, peritonitis, salpingitis, meningitis, and thrombophlebitis.
• People with underlying diseases, such as HIV infection, are particularly susceptible.

Campylobacter – Other Species

• C. coli: Pigs and poultry; human infections.
• C. concisus: Human infections.
• C. helveticus: Dogs and cats.
• C. hyloileri: Pigs.
• C. jejuni subsp. doylei: Human infections.
• C. lari: Gulls and other avian species, dogs, and cats.
• C. upsaliensis: Dogs; human infections.
• C. sputorum bivar bubulus: Cattle and sheep; human infections.
• C. sputorum bivar fecalis: Cattle and sheep; intestinal and genital tracts.
• C. sputorum bivar sputorum: Cattle and sheep; genital tract.
• The human infections above are opportunistic and include wound infections, diarrhea, proctitis, endocarditis, gastroenteritis, meningitis, sepsis, abscesses, and periodontal disease.

Campylobacter jejuni

• Occurs frequently as a commensal in the intestinal tract of many species of domestic and wild animals.
• C. jejuni causes infections characterized by diarrhea and enterocolitis in dogs, cats, sheep, goats, calves, laboratory animals, mink, ferrets, and other animals.
• C. jejuni can also cause abortion in bitches, ewes, and cows. It causes mastitis in cows.
• C. jejuni is the cause of avian infectious hepatitis of chickens and turkeys.

Campylobacter coli

• Occurs as a commensal in the intestinal tract of poultry and swine.
• It produces a heat-labile enterotoxin.
• It is rarely pathogenic and is easily confused with C. jejuni.

Campylobacter upsaliensis

• Has been recovered from feces of both healthy and diarrheic dogs and cats.
• Has been recovered from feces of healthy children.
• C. upsaliensis causes infrequent foodborne diarrheic infections.

Helicobacter

• Resembles campylobacter and were previously classified in the genus Campylobacter.
• Gram-negative, spiral and curved, motile (several sheathed flagella) and microaerophilic.
• At least 19 species of Helicobacter have been named.
• All occur in the stomach or intestine of animals and humans worldwide.
• Helicobacter spp. are carried in the stomach or intestine of many animals without causing apparent disease.
• The carrier rate of Helicobacter pylori for humans is 50%.

Helicobacter – Pathogenicity

• H. pylori causes chronic gastritis, duodenitis, and duodenal ulcer disease in humans.
• Gastric ulcer disease and gastric adenocarcinoma are epidemiologically associated with H. pylori.
• H. pylori has the potential to cause similar disease in cats.
• Other Helicobacter species implicated in gastric disease in humans include: H. canis, H. felis, H. rappini, H. bills, and H. heilmannii ( H. bizzozeronii).
• These other species can cause gastritis and serious diseases in dogs and cats.
• The clinical signs attributed to Helicobacter infections in dogs and cats are: vomiting, regurgitation, abdominal pain, fever, diarrhea, anorexia, weight loss, and poor condition.

Helicobacter – Laboratory Diagnosis

• Scrapings of the gastric mucosa are examined under phase microscopy for motile, helical-shaped organisms.
• Electron microscopy may be used to evaluate preparations.
• The isolation and identification of Helicobacter species are complex and are not attempted in most veterinary diagnostic laboratories.
• Skirrow's medium and chocolate agar with the addition of antibiotics are used for isolation.
• Incubation for up to a week may be required for appreciable growth.

This quiz explores the characteristics, virulence factors, and public health significance of Campylobacter species, particularly focusing on C. fetus and C. jejuni. Test your knowledge on their pathogenic mechanisms and the role they play in animal and human health.