Campylobacter & Lawsonia: Characteristics & Transmission

• These notes cover Campylobacter, Pseudomonas, Bordetella, and Brucella, detailing their characteristics, infections, and control measures.

Campylobacter

• Major cause of gastrointestinal infections in humans, dogs, and cats, leading to diarrhea.
• Short, curved rods found in the reproductive and alimentary tracts of animals and humans.

Campylobacter Species

• Campylobacter fetus subsp. venerealis (Cattle)
• C. jejuni
• C. coli
• C. consicus
• C. helveticus
• C. hyointestinalis
• C. mucosalis
• C. lari

Morphology

• Gram-negative, slender, curved short rods.
• Two or more cells form S or gull-winged shapes.
• Possess cell wall, capsule, and flagella.

Growth Characteristics

• Microaerophilic, needing 3-15% oxygen.
• Energy from oxidizing amino acids, not from carbohydrate fermentation or oxidation.
• Lawsonia intracellularis hasn't been grown in artificial media.

Infection Reservoir

• Primarily milk
• Poultry carcasses
• Intestinal tracts of animals
• Feces of infected pigs
• Preputial crypts of bulls harbor C. fetus sp. venerealis.

Transmission

• Through the fecal-oral route.
• Artificial insemination.
• Coitus.
• Direct or Indirect contact

Diseases

• Dogs and Cats: C. jejuni causes diarrhea and gastroenteritis by invading the small intestines and destroying the mucosal epithelium, leading to bloody feces.
• Cattle: C. fetus subsp. venerealis results in infertility and abortions; cattle are healthy carriers.
• Sheep and Birds: C. fetus subsp. fetus causes abortion.
• Swine: C. hyointestinalis and C. mucosalis cause proliferative enteritis.
• L. intracellularis causes necrotic enteritis, regional ileitis, and proliferative hemorrhagic enteropathy.

Virulence Factors

• Toxin similar to cholera toxin
• Heat-labile toxin (LT) that elevates intracellular cAMP.
• Cytotonic and cytotoxic toxin
• Cyto-lethal distending toxin
• Hemolysin
• Hepatotoxin
• Mannose-resistant adhesin
• Ability to survive in mononuclear phagocytes.

Lab Diagnosis

• Feces
• Intestinal scrapings
• Preputial samples
• Smegma
• Stomach contents
• Blood and Thiol agar are preferred culture media.
• Microscopic examination of wet mounts (tumbling motility).
• Staining of bacterial smears using Romanovsky stain (curved rods) and Warthin-Starry (modified acid-fast stain).
• Bacterial cultivation and isolation using Campy-CVA medium.
• PCR for amplifying Campylobacter DNA.

Treatment

• Tetracyclines
• Erythromycin
• Tylosin
• Quinolones

Control

• Practice hygienic measures and disinfection protocols.

Pseudomonas

• Rarely involved in primary diseases.
• Difficult to eliminate from compromised sites.
• Produces grapelike or ammoniacal odors.
• Replaces normal flora after antibiotic use due to resistance.

Species

• P. mallei
• P. pseudomallei
• P. aeruginosa
• P. maltophilia

Morphology

• Gram-negative aerobes.
• Capsules may be produced.
• Motile via polar flagella.
• Some forms are piliated.
• Form many protein exotoxins (A, S), elastase, bacteriocins (Pyocins), pigments (pyocyanins), siderophores, pyochelins and pyoverdin.

Growth Characteristics

• Growth enhanced by blood agar.
• Grows on common media with glycerol and blood.
• Wide temperature range (4-41°C).
• Ferments glucose.

Infection Reservoirs

• Soil
• Infected water
• Infected hosts
• General environment
• Endogenous exposure
• Contaminated feed
• Fomites
• Entry through ingestion or wound infections.

Diseases

• Glanders in Horses: P. mallei (Burkholderia mallei) causes systemic pyogranulomatous infection with thick nodules and ulcers in the upper respiratory tract.
• Melioidosis in Humans: P. pseudomallei or Burkholderia pseudomallei causes suppurative foci or granulomas.
• Green Wool Infection (Sheep) and ear infections (Dogs and cats) are caused by Pseudomonas aeruginosa.

Clinical Signs of Glanders

• Nasal discharges
• Lymphadenitis of the head and neck
• Swellings along the upper respiratory tract (Pulmonary form)
• Pain in muscle
• Dermal abscesses (Cutaneous/Farcy)
• Nodular induration of cranial lymph nodes

Glanders forms

• Pulmonary
• Nasal
• Skin (farcy)

Virulence Factors

• Exotoxin A: Inhibits protein synthesis.
• Extracellular slime: Antiphagocytic, aids tissue penetration.
• Elastase: Destroys lung parenchyma in pneumonia cases.
• Bacteriocins and pigments.
• Pyocyanin and siderophores.

Lab Diagnosis

• Nodules from nasal passages.
• Lymph nodes
• Blood

Agent Identification

• Bacterial cultivation (glycerol-enriched or selective media).
• Mallein test (subcutaneous, ophthalmic, intrapalpebral).
• Bacteriocin typing (pyocin kills other strains of the same species).
• Phage typing (lysis patterns on test strains).

Treatment

• Gentamycin
• Carbenicillin
• Tobramycin
• Ciprofloxacin
• Ticarcillin
• Clavulanic acid
• Enrofloxacin
• Neomycin

Prevention and control

• Early diagnosis and elimination of reacting animals.
• Culling/ elimination of infected animals.

Bordetella

• Coccobacillary bacteria that invade ciliated respiratory epithelia.

Species

• B. bronchiseptica.
• B. avium.
• B. pertussis.
• B. parapertussis.

Characteristics

• Gram-negative coccobacilli.
• Small, blue-gray colonies on blood agar.
• Piliated, showing bipolar staining.
• Pleomorphic with a capsulated envelope (B. bronchiseptica).
• Motile via peritrichous flagella.
• Some have surface fibrils.
• Possess heat-labile and heat-stable K antigens.

Growth

• Aerobic.
• Utilizes citrate as a carbon source.
• Obtains energy from amino acid oxidation.
• Facultative intracellular parasite (B. bronchiseptica).

Reservoirs

• Wild and domestic carnivores.
• Nasopharynx of healthy animals.
• Carrier sows.

Transmission

• Airborne
• Water

Diseases

• Swine Atrophic Rhinitis: B. bronchiseptica causes ciliary paralysis, inflammation, and nasal irritation, leading to turbinate atrophy and distortion.
• Kennel Cough: B. bronchiseptica causes hacking cough in dogs.
• Rhinotracheitis in Turkeys: B. avium causes sinusitis, air sacculitis, nasal exudates, conjunctivitis, rales, and dyspnea.
• Acute Coryza in Turkeys
• Pneumonia in Sheep: B. parapertussis.
• Whooping Cough in Humans: B. parapertussis.

Clinical Signs of Swine Atrophic Rhinitis

• Sneezing
• Coughing
• Turbinate atrophy
• Distortion of the nasal septum
• Shortening and twisting of the upper jaw

Virulence Factors

• Siderophores
• Histamine-like scrutinizing factor
• Adhesins
• Oxidase
• Urease
• Catalase
• Adenylate cyclase
• Fibrillar material
• Dermonecrotic toxin
• Proteases
• Hemolysins
• Hemagglutinins
• Tracheal cytotoxins

Lab Diagnosis

• Tracheal aspirates
• Nasal swabs
• Tissues from transverse head sections.

Agent Identification

• Bacterial cultivation on Bordet-Gengou agar, Blood agar, or Brain Heart infusion broth.
• Serodiagnosis

Treatment

• Erythromycin
• Nitrofurantoin
• Tetracycline

Prevention

• Disinfection and sanitation practices.
• Fumigation of kennels.
• Elimination of carrier animals.
• Isolation of infected dogs.

Brucella

• Obligate pathogens causing reproductive and reticuloendothelial tissue infections.
• Causes abortion in females; epididymitis and orchitis in males.
• Chronic, debilitating infections.

Species

• B. abortus
• B. canis
• B. ovis
• B. melitensis
• B. suis

Characteristics

• Gram-negative short rods or coccobacilli.
• Colonies range from smooth to rough with a bluish color.
• No capsules, flagella, or spores.
• Difficult to suspend in solution.
• Positive to Koster, Machiavello, and modified Ziel-Nielsen stains.
• Possess surface antigens (A and M) on the outer membrane.

Growth

• Aerobic at 37°C, requires 10-14 days incubation.
• Produces H2S.
• Urease positive.
• Needs enriched medium with 5% serum or blood.
• Varying oxygen requirements.
• Produces hydrogen sulfide, urease.

Reservoirs

• Cattle
• Swine
• Sheep
• Dogs
• Placenta
• Aborted fetuses
• Post-abortion uterine fluid

Transmission

• Direct and indirect contact with infected placentas, aborted fetuses, and uterine fluids.
• Ingestion of infected material.
• Direct transfer in utero.
• Venereal transmission.
• Consumption of contaminated milk.

Diseases

• Infectious Abortions: B. abortus causes abortions during any gestation stage by penetrating mucosal surfaces, attaching to organs, and multiplying inside macrophages.
• Poll Evil: Equine brucellosis.
• Infections in Weanlings and Suckling Piglets: B. suis leads to metritis, arthritis, spondylitis, lameness, paralysis, and mastitis.
• Infections in Sheep, Goats, Pigs, Cattle: B. ovis causes epididymitis and bacteremia without abortion.
• Infections in Dogs: B. canis leads to late abortion, lymphadenitis, splenitis, embryonic death, epididymitis, scrotal swelling, dermatitis, and testicular atrophy.

Features of Brucella

• Inflammation of the spleen
• Scrotal infection
• Testicular infection

Clinical Features of Brucella Infections

• Retained placenta in pigs
• Infectious abortion

Virulence Factors

• Superoxide dismutase
• A and M antigens
• Porin proteins and surface antigens on the outer membrane.
• L-form variants (persistence of infection).

Lab Diagnosis

• Aborted fetus
• Placenta
• Uterine exudates
• Abscesses of testes
• Milk and blood samples
• Sputum
• Liver
• Spleen
• Mesenteric lymph node
• Abomasal fluid

Agent Identification

• Bacterial culture and cultivation on Albini/Brucella agar.
• Gram staining of fetal contents.
• PCR and ELISA
• Brucella milk ring test.

Treatment

• Tetracycline
• Dihydrostreptomycin
• Minocycline

Prevention and Control

• Culling infected animals.
• Vaccination with B. abortus strain 19 or McEwen killed 45/20 vaccine.
• Neutering affected animals.