Bacteriology: Burkholderia, Bordetella, Fusobacterium, Mycobacteria
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Questions and Answers

What is the common outcome of the nodules in the nasal form of Glanders?

  • They remain intact and benign
  • They degenerate into deep ulcers (correct)
  • They remain dormant indefinitely
  • They disappear spontaneously

    • What is the primary method of diagnosis for Glanders?

  • Imaging techniques
  • Lymph node biopsies
  • Blood tests
  • Interpalpebral inoculation of mallein (correct)

    • What is a common outcome of untreated Glanders in the lungs?

  • Spontaneous resolution
  • Consolidation of lung tissue (correct)
  • Pulmonary edema
  • Pleural effusion

    • In which organs can nodules be seen in the Cutaneous form of Glanders?

    <p>Lymph nodes and skin</p> Signup and view all the answers

    What is the primary reason antimicrobials are not used to treat Glanders?

    <p>Countries are committed to eradication</p> Signup and view all the answers

    What is the significance of 'star-shaped' cicatrices in Glanders?

    <p>They are a result of tissue scarring</p> Signup and view all the answers

    What is the result of the Mallein test in hypersensitive horses?

    <p>Purulent conjunctivitis within 24 hrs and swelling of the eyelids</p> Signup and view all the answers

    What is the fate of equine imports that test positive for Glanders?

    <p>They are euthanized</p> Signup and view all the answers

    What is the histological feature of Glanders?

    <p>Vasculitis, thrombosis, and infiltration of degenerating inflammatory cells</p> Signup and view all the answers

    What is a consequence of the Pulmonary form of Glanders?

    <p>Pneumonia</p> Signup and view all the answers

    Which species of Burkholderia is associated with Glanders?

    <p>Burkholderia mallei</p> Signup and view all the answers

    What characteristic is shared by both Burkholderia mallei and Burkholderia pseudomallei?

    <p>They both produce pyogranulomatous disease</p> Signup and view all the answers

    Which of the following is the most common source of infection for Glanders in animals?

    <p>Ingestion of contaminated food and water</p> Signup and view all the answers

    Which region is NOT mentioned as endemic for Glanders?

    <p>Europe</p> Signup and view all the answers

    What is the incubation period range for acute Glanders?

    <p>3 days to 2 weeks</p> Signup and view all the answers

    Which animals are particularly susceptible to Glanders?

    <p>Felids</p> Signup and view all the answers

    Which of the following is not a clinical sign of acute Glanders?

    <p>Pyrexia</p> Signup and view all the answers

    What is the primary way Burkholderia mallei enters the body?

    <p>Through mucous membranes or skin breaks</p> Signup and view all the answers

    What categorizes Burkholderia mallei as a bioterrorism agent?

    <p>It is highly contagious and zoonotic</p> Signup and view all the answers

    Which factor is NOT listed as influencing the manifestation of Melioidosis?

    <p>Host's diet</p> Signup and view all the answers

    What characteristic differentiates Burkholderia pseudomallei from Gleners in terms of host range?

    <p>Large host range including humans</p> Signup and view all the answers

    In which condition is Melioidosis NOT typically presented?

    <p>Autoimmune</p> Signup and view all the answers

    What is a unique aspect of Burkholderia pseudomallei's natural habitat?

    <p>Can be endosymbiont within amoebae</p> Signup and view all the answers

    What route of transmission is unique to goats for Burkholderia pseudomallei?

    <p>Transplacental</p> Signup and view all the answers

    Which typical feature of Burkholderia pseudomallei is true regarding its interaction with environment?

    <p>It is a saprophyte</p> Signup and view all the answers

    Which of the following is NOT a transmission method for Burkholderia pseudomallei?

    <p>Vector-borne transmission by mosquitoes</p> Signup and view all the answers

    Which descriptor is NOT characteristic of the type of disease caused by Burkholderia pseudomallei?

    <p>Asymptomatic</p> Signup and view all the answers

    Which species is affected by conditions mimicking glanders?

    <p>Horses</p> Signup and view all the answers

    What type of lesions are primarily observed in melioidosis pathology?

    <p>Pyogranulomatous lesions</p> Signup and view all the answers

    Which of the following animals can show clinical signs similar to goats in the case of melioidosis?

    <p>Swine</p> Signup and view all the answers

    What is characteristic about the bacteria's survival mechanism within the cell?

    <p>They resist lysosomal contents and escape phagosomes and phagolysosomes.</p> Signup and view all the answers

    Which species has febrile and localized suppurative foci as symptoms?

    <p>Dogs</p> Signup and view all the answers

    Which feature is common to all members of the genus Bordetella?

    <p>Capable of intracellular survival</p> Signup and view all the answers

    Where is melioidosis endemic in humans?

    <p>SE Asia and Northern Australia</p> Signup and view all the answers

    Which mechanism allows microorganisms to move within the host cell during melioidosis?

    <p>Actin-based motility</p> Signup and view all the answers

    What is the characteristic shape of Bordetella bacteria?

    <p>Coccobacilli</p> Signup and view all the answers

    What is the primary function of the Tracheal cytotoxin?

    <p>Damages ciliated epithelial cells and inhibits DNA synthesis</p> Signup and view all the answers

    Which toxin is responsible for increasing intracellular concentration of cAMP levels?

    <p>Adenylyl cyclase toxin</p> Signup and view all the answers

    Which Bordetella species is responsible for causing whooping cough in humans?

    <p>B.pertussis</p> Signup and view all the answers

    What is the primary method of transmission for Bordetella spp.?

    <p>Airborne transmission via aerosols</p> Signup and view all the answers

    Which virulence factor is responsible for biofilm formation in Bordetella spp.?

    <p>Adhesins</p> Signup and view all the answers

    What is the primary function of the Osteo Toxin?

    <p>Inhibits differentiation of osteoblasts in bone tissues</p> Signup and view all the answers

    Which toxin is responsible for hemolytic and pore-forming activity?

    <p>Adenylyl cyclase toxin</p> Signup and view all the answers

    What is the significance of Multiple Iron Acquisition Systems in Bordetella spp.?

    <p>Allows for iron uptake from the host</p> Signup and view all the answers

    Which virulence factor is responsible for the inhibition of differentiation of osteoblasts in bone tissues?

    <p>Osteo Toxin</p> Signup and view all the answers

    What is the primary mechanism of action of the Pertussis toxin?

    <p>Increases intracellular cAMP levels</p> Signup and view all the answers

    Which effect is directly caused by the bacterial attachment of Bordetella to ciliated epithelial cells?

    <p>Production of ciliostasis</p> Signup and view all the answers

    What is a common consequence of Bordetella interference with phagocytosis in the host?

    <p>Hindered clearance mechanisms in the upper respiratory tract</p> Signup and view all the answers

    What typically characterizes the catarrhal phase of Bordetella infection?

    <p>Sneezing and coughing</p> Signup and view all the answers

    Which event in the pathogenesis of Bordetella contributes to secondary pneumonia?

    <p>Accumulation of mucus and fluid</p> Signup and view all the answers

    What outcome is linked to the production of ciliostasis by Bordetella?

    <p>Initiation of inflammation</p> Signup and view all the answers

    How does Bordetella contribute to progressive atrophic rhinitis in pigs?

    <p>Susceptibilization of turbinates to P.multocida toxin</p> Signup and view all the answers

    What is the primary factor in Bordetella's ability to avoid immune clearance in the host?

    <p>Production of Adenyl cyclase toxin</p> Signup and view all the answers

    Which clinical sign is uncommon but may occur during the catarrhal phase of Bordetella infection?

    <p>Fever</p> Signup and view all the answers

    What is the consequence of Bordetella-induced loss of iron regulation in tracheal epithelial cells?

    <p>Accumulation of fluid</p> Signup and view all the answers

    Which pathology phase includes rhinitis and sinusitis?

    <p>Suppurative phase</p> Signup and view all the answers

    What ages of piglets are most commonly affected by primary pneumonia caused by Bordetella bronchiseptica?

    <p>3-4 days old</p> Signup and view all the answers

    Which pathogen is responsible for the progressive form of atrophic rhinitis in swine?

    <p>Combined infection with Pasteurella multocida and Bordetella bronchiseptica</p> Signup and view all the answers

    Which of the following is NOT commonly associated with Bordetella bronchiseptica infections in young dogs?

    <p>Canine distemper virus (CDV)</p> Signup and view all the answers

    Which clinical sign is NOT typically associated with Bordetella bronchiseptica infection in cats?

    <p>Otitis externa</p> Signup and view all the answers

    What is a key characteristic of Bordetella bronchiseptica pneumonia in dogs?

    <p>Typically a secondary infection</p> Signup and view all the answers

    Which of the following is a common outcome of a Bordetella bronchiseptica infection in guinea pigs?

    <p>Severe respiratory disease</p> Signup and view all the answers

    What is the usual outcome for dogs recovering from canine infectious tracheobronchitis without treatment?

    <p>Recovery within a few weeks</p> Signup and view all the answers

    What is a key difference in the respiratory diseases caused by Bordetella bronchiseptica in cats compared to dogs?

    <p>Dogs often have secondary infections</p> Signup and view all the answers

    What type of infection is Bordetella bronchiseptica in swine subcategorized as when it progresses without Pasteurella multocida involvement?

    <p>Non-progressive atrophic rhinitis</p> Signup and view all the answers

    How long can cats carry Bordetella bronchiseptica asymptomatically following recovery?

    <p>Up to 19 weeks</p> Signup and view all the answers

    Which natural habitat is NOT commonly associated with Fusobacterium necrophorum?

    <p>Skin</p> Signup and view all the answers

    Which disease is primarily associated with Fusobacterium necrophorum in cattle and has significant economic impact?

    <p>Hepatic necrobacillosis</p> Signup and view all the answers

    What condition must be met for Fusobacterium necrophorum to colonize the rumen wall?

    <p>Epithelial damage</p> Signup and view all the answers

    Which type of abscesses is Fusobacterium necrophorum known to cause in wild ruminants and marsupials?

    <p>Jaw abscesses</p> Signup and view all the answers

    Which disease is specifically referred to as 'necrobacillosis'?

    <p>Liver abscesses in pigs</p> Signup and view all the answers

    What is the initial cause of liver abscesses secondary to rumen damage in cattle?

    <p>Fermentation of grain</p> Signup and view all the answers

    Which factor does NOT directly predispose the rumen wall to colonization by Fusobacterium necrophorum?

    <p>High protein diet</p> Signup and view all the answers

    What sequence correctly describes the pathogenesis starting from the colonization of Fusobacterium necrophorum?

    <p>Epithelial damage -&gt; Local infection -&gt; Small rumen wall abscesses -&gt; Bacterial emboli -&gt; Liver abscesses</p> Signup and view all the answers

    Which type of Fusobacterium necrophorum infection is least associated with economic impacts in cattle?

    <p>Jaw abscesses</p> Signup and view all the answers

    Which anatomical region is primarily involved when Fusobacterium necrophorum causes footrot?

    <p>Hoof</p> Signup and view all the answers

    What is a likely consequence for guinea pigs that survive a bronchiseptica infection?

    <p>They become chronic, asymptomatic carriers.</p> Signup and view all the answers

    Which clinical sign is NOT associated with respiratory infections caused by Bordetella hinzii in birds?

    <p>Laboured breathing</p> Signup and view all the answers

    What characteristic does Fusobacterium necrophorum share with other members of the genus Fusobacterium?

    <p>Production of butyric acid</p> Signup and view all the answers

    What allows anaerobic bacteria to survive initial oxygen exposure in infected tissues?

    <p>Presence of protective enzymes like SOD and catalase</p> Signup and view all the answers

    Which species is primarily affected by 'Turkey coryza'?

    <p>Young turkeys</p> Signup and view all the answers

    What type of infections can Fusobacterium canifelinum often be isolated from?

    <p>Bite wounds in humans</p> Signup and view all the answers

    Which of the following species is considered a major animal pathogen within the genus Fusobacterium?

    <p>Fusobacterium necrophorum</p> Signup and view all the answers

    Which product of anaerobic bacteria is known for creating a putrid odor and having cytotoxic effects?

    <p>Butyric acids</p> Signup and view all the answers

    Which disease in birds is caused by Bordetella avium?

    <p>Turkey coryza</p> Signup and view all the answers

    What condition might develop if bronchiseptica infection in guinea pigs is not treated quickly?

    <p>Fatal pneumonia</p> Signup and view all the answers

    What is the main feature that distinguishes Mycobacterium leprae from other species within the Mycobacterium genus?

    <p>Its obligate intracellular parasitism</p> Signup and view all the answers

    Which structural characteristic in Mycobacterium species provides resistance against chemicals and antibiotics?

    <p>Mycolic acid layer</p> Signup and view all the answers

    What is the differentiating factor for Mycobacterium caprae within the Mycobacterium TB Complex?

    <p>Its adaptation to goats</p> Signup and view all the answers

    How is Mycobacterium tuberculosis primarily transmitted?

    <p>Aerosols</p> Signup and view all the answers

    Which mycobacterium species is NOT part of the Mycobacterium TB Complex?

    <p>Mycobacterium avium</p> Signup and view all the answers

    Which Mycobacterium species primarily causes TB-like infections in birds?

    <p>Mycobacterium avium ssp. avium</p> Signup and view all the answers

    What characteristic defines the members of the CMNR group?

    <p>Production of mycolic acid</p> Signup and view all the answers

    What is the primary method of zoonotic transmission for Mycobacterium bovis?

    <p>Ingestion of unpasteurized milk</p> Signup and view all the answers

    Why is Mycobacterium canettii unique among other Mycobacterium species?

    <p>Its host range is unknown</p> Signup and view all the answers

    What is a significant characteristic of Mycobacterium microti?

    <p>It causes TB-like diseases in voles and occasionally humans</p> Signup and view all the answers

    What is the primary mediator for driving macrophages to mature and contain Mycobacterium infection?

    <p>Interferon Gamma</p> Signup and view all the answers

    What is the role of T-helper 1 cells in immunity to mycobacterium infection?

    <p>Stimulating macrophages and triggering bactericidal action</p> Signup and view all the answers

    Which factor is crucial for the differentiation of T-helper cells?

    <p>Presence of Interleukin-12</p> Signup and view all the answers

    How do mycobacteria avoid macrophage activation and bactericidal response?

    <p>By inhibiting phagosome acidification and preventing lysosome fusion</p> Signup and view all the answers

    Which cells form Granulomas or Tubercles during mycobacterial infection?

    <p>Epithelioid macrophages</p> Signup and view all the answers

    What outcome can caseous necrosis in tuberculose lesions lead to?

    <p>Calcification or liquefaction</p> Signup and view all the answers

    Which form of Mycobacterium is associated with Crohn's disease in humans?

    <p>Ssp. paratuberculosis</p> Signup and view all the answers

    What is a common method of transmission for mycobacterial infections in humans?

    <p>Ingestion of unpasteurized milk</p> Signup and view all the answers

    What type of immune response is key to disease onset after mycobacterial infection?

    <p>T-helper 1 mediated immunity</p> Signup and view all the answers

    Which mycobacterial species is not primarily associated with human infection?

    <p>Ssp. silvaticum</p> Signup and view all the answers

    What is the primary site of infection in birds infected with M.avium avium?

    <p>Alimentary canal</p> Signup and view all the answers

    Which species of animals are susceptible to M.bovis, M.avium paratuberculosis, and M.avium hominissuis?

    <p>Sheep and goats</p> Signup and view all the answers

    What is the common sign of advanced disease in tuberculous infections?

    <p>Weight loss</p> Signup and view all the answers

    What is the primary route of infection for M.avium paratuberculosis in ruminants?

    <p>Fecal-oral</p> Signup and view all the answers

    Which species of animals are more susceptible to mammalian than to avian mycobacteria?

    <p>Canaries</p> Signup and view all the answers

    What is the primary site of infection in dogs infected with M.bovis?

    <p>Intestines</p> Signup and view all the answers

    What is the characteristic of lesions in dogs infected with M.bovis?

    <p>Foreign body reaction</p> Signup and view all the answers

    Which species of mycobacteria is commonly found in the environment and causes opportunistic TB-like infections?

    <p>Nontuberculous mycobacteria</p> Signup and view all the answers

    What is the incubation period for Johne’s disease?

    <p>12 months or longer</p> Signup and view all the answers

    What is the primary method of transmission for Johne’s disease?

    <p>Fecal-oral</p> Signup and view all the answers

    What percentage of infected animals progress to the terminal stage of M.avium paratuberculosis?

    <p>3-5%</p> Signup and view all the answers

    What is a characteristic gross appearance of intestinal mucosa in M.avium paratuberculosis?

    <p>Corrugated</p> Signup and view all the answers

    Which of the following is NOT a cost-effective treatment for M.avium paratuberculosis?

    <p>Antimicrobial treatment</p> Signup and view all the answers

    What is the primary role of interferon gamma in the context of TB?

    <p>To contribute to the host's protection against mycobacterial infection</p> Signup and view all the answers

    What is a common feature of feline leprosy syndrome?

    <p>Slow progression</p> Signup and view all the answers

    How is M. bovis typically transmitted?

    <p>Through shedding into milk and direct aerosol transmission</p> Signup and view all the answers

    What is a common location of lesions in feline leprosy syndrome?

    <p>All of the above</p> Signup and view all the answers

    What is the result of the binding of mycobacterial cell wall to pattern recognition receptors on macrophages?

    <p>Non-opsonic cell entry and inhibited phagocytosis</p> Signup and view all the answers

    What is a characteristic of the nodules in feline leprosy syndrome?

    <p>Painless and movable</p> Signup and view all the answers

    What is the characteristic of the inflammation seen in opportunistic dermal infections in small animals and paraTB in ruminants?

    <p>Diffuse and granulomatous without typical encapsulation</p> Signup and view all the answers

    What is a consequence of not treating feline leprosy syndrome with antimicrobials?

    <p>Local spread of lesions</p> Signup and view all the answers

    What is the fate of the bacteria in mature tubercles?

    <p>They are kept in a non-replicating latent stage</p> Signup and view all the answers

    What is a feature of M.smegmatis and M.ulcerans infections in cats and dogs?

    <p>Chronic, non-healing, and progressive skin lesions</p> Signup and view all the answers

    What is the consequence of reactivation and dissemination of latent TB?

    <p>The bacteria are released from the tubercles and can cause disease in the animal or be transmitted to others</p> Signup and view all the answers

    What is a method used for identifying exposed and shedding animals in M.avium paratuberculosis?

    <p>Serology and fecal molecular tests</p> Signup and view all the answers

    What is the primary mechanism by which mycobacteria inhibit the maturation of phagolysosome?

    <p>By inhibiting the fusion of phagosomes and lysosomes</p> Signup and view all the answers

    What is the best approach for overall herd health in M.avium paratuberculosis?

    <p>Prevention and elimination of infected animals</p> Signup and view all the answers

    What is the role of granulomas in the context of TB?

    <p>To central to mycobacterial control in the body</p> Signup and view all the answers

    What is the primary difference between M. bovis and M. avium pathogenesis?

    <p>The mode of transmission</p> Signup and view all the answers

    What is the outcome of the infection in animals with weak or waning immune responses?

    <p>The centres of tubercles become necrotic and release infectious bacilli</p> Signup and view all the answers

    Study Notes

    Burkholderia Genus

    • Gram-negative, aerobic, rod-shaped bacteria
    • Found in acidic soil, associated with soil fungi, with over 100 species
    • Two species important in veterinary medicine: Burkholderia mallei and Burkholderia pseudomallei, both producing pyogranulomatous disease and designated as category B bioterrorism agents

    Glanders Disease (Burkholderia mallei)

    • Contagious, acute or chronic, and usually fatal disease
    • Characterized by nodule development in upper respiratory tract, lungs, and skin
    • Infectious to humans, with 95% fatality rate if left untreated due to septicemia
    • Commonly transmitted through contaminated food and water, less commonly through contaminated fomites and aerosols
    • Affects horses (Equidae), dogs, cats, camels, goats, and sheep, with felids being particularly susceptible
    • Endemic in parts of Asia, Africa, and South America

    Acute Glanders Disease

    • Incubation period of 3 days to 2 weeks
    • Fatal in ~2 weeks, predominantly in donkeys and felids
    • Clinical signs include septicemia, high fever, weight loss, thick mucopurulent nasal discharge, respiratory signs, and death

    Chronic Glanders Disease

    • More common in horses, with donkeys and mules being affected more severely
    • Animals may live for years, disseminating the organism
    • Three manifesting forms:
      • Nasal Form: nodules in nasal mucosa, degenerating into deep ulcers
      • Pulmonary Form: small tubercle-like nodules in lungs, with consolidation of lung tissue and pneumonia
      • Cutaneous Form ("Farcy"): nodules along lymph vessels, degenerating and ulcerating

    Diagnosis and Control of Glanders

    • Mallein test: interpalpebral inoculation of mallein, with hypersensitive horses developing purulent conjunctivitis and eyelid swelling within 24 hours
    • Treatment with antimicrobials is deemed inappropriate, as it does not reliably produce a cure and infection can remain persistent
    • Equine imports from endemic regions are mallein tested, and if positive, euthanized

    Burkholderia pseudomallei (Whitmore's Disease)

    • Gram-negative, aerobic, rod-shaped bacteria that is facultative intracellular
    • Causes pyogranulomatous disease called Melioidosis, affecting a wide host range including humans
    • Superficially resembles Glanders, but has a large host range and is a saprophyte

    Transmission and Habitat

    • Found in soil and water in subtropical and some extratropical regions
    • Can be transmitted through direct contact with contaminated soil or surface water, inhalation, ingestion, wound infections, and arthropod bites
    • Can also be transmitted transplacental in goats

    Melioidosis (Whitmore's Disease)

    • Can be systemic or localized, acute, chronic, subclinical, latent, or fulminant
    • Manifestation depends on the extent and distribution of the lesions, strain differences, and the host's innate and adaptive immune status
    • Treatment is costly, prolonged, and usually unsuccessful, with no commercially available vaccines

    Species Diseases

    • Horses: mimics Glanders
    • Cattle: acute and chronic diseases localizing in lungs, joints, and uterus
    • Sheep: arthritis and lymphadenitis
    • Goats: loss of condition, respiratory and CNS disturbances, arthritis, and mastitis
    • Swine: similar to goats, with abortions and diarrhea
    • Dogs: febrile, localized suppurative foci

    Epidemiology of Melioidosis

    • Clinical disease is usually sporadic
    • Endemic in humans in SE Asia and Northern Australia
    • Host range is virtually unlimited, with non-mammalian cases documented in birds, tropical fish, and reptiles
    • Humans, especially veterinarians, can acquire infection from a wide range of animals

    Mechanism of Pathogenesis

    • Microorganisms are taken up via phagocytosis and survive inside the cell by being resistant to lysosomal contents and escaping phagosomes and phagolysosomes
    • Bacteria gain actin-based motility and undergo 'budding' from affected and unaffected cells
    • Infected cells release inflammatory cytokines and undergo apoptosis

    Pathology

    • Primary pyogranulomatous lesions characterized by single to multiple suppurative or caseous nodules in organs
    • Commonly affects lungs, spleen, liver, and associated lymph nodes
    • Small abscesses tend to coalesce into large foci

    Genus Bordetella

    • Gram-negative, small rods that tend to look like coccobacilli
    • 16 species, with 3 species causing respiratory diseases in animals
    • Found in animal respiratory tracts and has an affinity for ciliated epithelial cells
    • Capable of intracellular survival, and healthy animals are carriers for B. bronchiseptica
    • Environmental reservoir is amoebae

    Bordetella spp. Virulence Factors

    • Adhesins, biofilms, LPS, outer membrane proteins, and multiple iron acquisition systems are involved in Bordetella virulence
    • Tracheal cytotoxin damages ciliated epithelial cells, interfering with DNA synthesis
    • DNT (dermonecrotizing toxin) causes dermal necrosis following injection into the skin
    • Exotoxins alter the actin cytoskeleton of affected cells, inhibiting differentiation of osteoblasts in bone tissues, leading to turbinate atrophy
    • Adenylyl cyclase toxin has hemolytic and pore-forming activity, increasing intracellular CAMP levels and disrupting iron and fluid regulation

    Transmission of Bordetella

    • B. bronchiseptica can cause respiratory disease in nearly all animals, primarily through airborne transmission via aerosols
    • Environmental contamination and direct transmission through contaminated water and litter are also significant factors
    • B. avium is directly transmitted in turkeys via contaminated water and litter

    Pathogenesis of Bordetella

    • Bacterial attachment to ciliated epithelial cells leads to expression of adhesins with toxic or pro-inflammatory properties, production of ciliostasis, and initiation of inflammation
    • Adherence to immune cells and release of adenyl cyclase toxin and effector proteins interferes with phagocytosis, leading to proliferation and active inflammation
    • Mucus and fluid accumulation in the upper respiratory tract results in loss of control in iron and fluid regulation, leading to secondary pneumonia

    Consequences of Bordetella-induced Changes

    • Depression of respiratory clearance mechanisms facilitates complications
    • In pigs, B. bronchiseptica causes nasal irritation, making turbinates susceptible to P. multocida toxin, leading to progressive atrophic rhinitis or non-progressive, mild, reversible turbinate hypoplasia

    Pathology of Bordetella Infection

    • Clinical disease caused by Bordetella is characterized by pathogen attachment, functional impairment, and destruction of ciliated respiratory epithelium
    • The disease process begins with a catarrhal phase, followed by a suppurative phase, which may result in pneumonia or air sacculitis
    • Compromised host clearance mechanisms in the upper respiratory tract may result in pneumonia or air sacculitis, enhanced by secondary bacterial pathogens

    Bordetella Infections

    • Swine:
      • Atrophic rhinitis: progressive form is a combined infection with P. multocida and B. bronchiseptica, while non-progressive form is caused by B. bronchiseptica alone
      • Transient and self-limiting, affecting piglets 3-4 weeks old
      • Pneumonia: usually a secondary infection, but primary pneumonia can occur in neonatal piglets (3-4 days old), causing coughing, dyspnea, high morbidity, and high mortality at times

    Canine Infectious Tracheobronchitis (Kennel Cough)

    • Caused by B. bronchiseptica
    • Clinical disease most common in young dogs or mature dogs with a lowered immune system
    • Often associated with viral infections, including canine influenza virus (CIV), canine parainfluenza virus (CPV), canine adenovirus 1 or 2 (CAV-1/2), and canine herpesvirus (CHV)
    • Disease outbreaks occur rapidly in kennels and animal hospitals, with an incubation period of approximately 1 week
    • Clinical symptoms:
      • Acute coughing
      • Gagging and retching (severe cases)
      • Recovery within a few weeks without treatment, but bacteria can persist and cause a relapse infection
    • Pneumonia: usually secondary and associated with other pathogens

    Feline Upper Respiratory Disease

    • B. bronchiseptica is becoming increasingly important in terms of feline respiratory infections
    • Clinical signs:
      • Mild tracheobronchitis
      • Conjunctivitis
      • Nasal discharge
      • Sneezing
      • Coughing
    • Signs resolve after 10 days, but cats can carry the organism asymptomatically for up to 19 weeks following recovery

    Guinea Pigs

    • Extremely susceptible to B. bronchiseptica infections
    • Acute development of disease associated with high mortality
    • Clinical signs:
      • Depression
      • Ruffled fur
      • Labored breathing
      • Sneezing
      • Anorexia
      • Mucopurulent or catarrhal exudate in the nares (may be present)
    • Without quick treatment, usually progresses to fatal pneumonia
    • Necropsies show consolidation of cranioventral lung tissue, fibrinous suppurative pleuritis, and exudate in the airways
    • Guinea pigs that survive infection will become chronic, asymptomatic carriers

    Poultry and Birds

    • Two species cause diseases in birds and are associated with stunted growth and tracheal collapse:
      • B. avium (‘Turkey coryza’): affects young turkeys, leading to tracheobronchitis, sinusitis, and air sacculitis
      • B. hinzii: commensal in poultry respiratory tract, causing clinical signs such as nasal exudate, conjunctivitis, sneezing, and dyspnea
    • Morbidity can be high, mortality is generally low except for cases of secondary infections
    • Recovery can begin after approximately 2 weeks, but illness can persist for 6 weeks

    Gram-Negative Anaerobes

    • Most anaerobes are part of normal microbiota in the mouth, GI tract, upper respiratory tract, and female urogenital tract in various species
    • Genera of anaerobic bacteria associated with animal diseases include:
      • Bacteriodes
      • Dichelobacter
      • Treponema
      • Porphyromonas
      • Prevotella
      • Fusobacterium

    General Pathogenesis of Anaerobic Bacteria

    • Microenvironments:
      • Process of establishing infection is dependent on the site involved
      • Bacteria need to generate a local anaerobic microenvironment or be able to tolerate oxygen exposure
      • Microenvironments may be created by bacterial damage to the host or because of synergistic interactions with facultative anaerobic bacteria that can utilize oxygen
    • Protective enzymes:
      • Many anaerobes can grow at low oxygen tension by using enzymes that protect them against oxygen, such as superoxide dismutase (SOD), catalase, and nicotinamide adenine dinucleotides (NAD) oxidase
    • Bacterial products = damage:
      • Tissue destruction may occur from host immune responses and inflammation that are triggered by bacterial products
      • Local release of a wide variety of inflammatory cytokines
      • Fermentation products create characteristic putrid odor of anaerobic infections and have inflammatory cytotoxic effects, including:
        • Lactic acid
        • Butyric acids
        • Ammonia

    Genus Fusobacterium

    • Gram-negative, obligate anaerobic, non-motile, spindle-shaped (fusiform) or long filamentous bacilli
    • 17 species, all producing large amounts of butyric acid as a fermentation product
    • Species of relevance to veterinary medicine and public health:
      • Fusobacterium necrophorum: major animal pathogen
      • Fusobacterium canifelinum, nucleatum, and russi: members of normal oral microbiota in dogs and cats, frequently isolated from bite wounds in humans
      • Fusobacterium equinum: normal part of oral microbiota in horses, isolated from oral-associated and respiratory diseases of horses
    • Fusobacterium necrophorum:
      • 2 subspecies: necrophorum and funduliforme, varying in cellular morphology, colonial characteristics, growth patterns in broth, extracellular enzymes, virulence factors, and general virulence and infrequency of occurrence in infections
      • Natural habitat: mouth, gastrointestinal tract, urogenital tract, and soil, especially well-manured soil
    • Fusobacterium necrophorum types of diseases and pathologic changes:
      • Major bovine pathogen, causing necrobacillosis and associated with numerous necrotic disease conditions
      • Hepatic necrobacillosis (liver abscesses): occurs secondarily to damage of the rumen wall epithelium, resulting in rumen acidosis and epithelial damage, which is required for F. necrophorum to colonize

    Genus Mycobacterium

    • 188 species, mostly saprophytic, obtaining food by absorbing dissolved organic material
    • Non-flagellated, rod-shaped, and aerobic, with varying lengths
    • Acid-fast, resisting decolorizing after staining, and cytochemically Gram-positive
    • Characterized by a mycolic acid layer or mycomembrane, conferring high resistance to chemicals and antibiotics

    Pathogenic Species: Host-Adapted Species

    • Mycobacterium tuberculosis (humans): host-adapted, rarely infects other animals, and has limited environmental survival capability
    • Mycobacterium bovis (cattle, humans): zoonotic, transmitted bidirectionally via aerosols and ingestion of unpasteurized milk
    • Mycobacterium pinnipedii (seals): host-adapted strain
    • Mycobacterium caprae (goats): host-adapted strain
    • Mycobacterium mungi (banded mongoose): host-adapted strain
    • Mycobacterium microti (voles, humans): host-adapted strain
    • Mycobacterium canettii (unknown): host range unknown

    Pathogenic Species: Environmentally Adapted Species

    • Mycobacterium avium complex: found in surface water, includes distinct species, and causes TB-like infections in birds
    • Mycobacterium intracellulare: opportunistic pathogen
    • Mycobacterium avium: includes four subspecies, causing infections in birds, swine, humans, and ruminants
    • Mycobacterium chelonae, Mycobacterium fortuitum, Mycobacterium kansasii, Mycobacterium marinum, and Mycobacterium ulcerans: all opportunistic pathogens

    Pathogenesis of Mycobacterial Infections

    • Transmission: inhalation of aerosols, ingestion of unpasteurized milk, and inoculation through damaged skin
    • Pathogenesis: entry via mucosa or skin breach, phagocytosis by macrophages, and avoidance of macrophage activation and bactericidal response

    Progression to Clinical Disease

    • Clinical disease depends on the number of bacteria, infecting dose, virulence, and development of anti-mycobacterial cell-mediated immunity
    • Disease onset: ~3 weeks after infection, mediated by T-helper 1 cells, IL-12, and Interferon Gamma
    • Granulomas or tubercles form, containing infected macrophages, epithelioid cells, lymphocytes, and fibroblasts
    • Caseous necrosis develops, dependent on disease outcome, and tubercles may enlarge and coalesce, eventually effacing large areas of tissue

    General Pathogenesis of TB

    • Infected animals mount both humoral and cell-mediated immune responses of varying efficacy
    • Interferon gamma is key to host protection
    • Granulomas are central to mycobacterial control in the body

    M.bovis Pathogenesis

    • Transmitted via direct aerosol and shedding into milk
    • Initial uptake via alveolar macrophages and epithelial cells
    • Binding of mycobacterial cell wall and pattern recognition receptors on macrophages
    • Persists in macrophage phagosome and inhibits maturation of phagolysosome
    • Proliferates in phagosomal vacuole

    M.avium Pathogenesis

    • Transmitted via fecal-oral route
    • Initial uptake via M cells of intestinal Peyer's Patches
    • Binding of mycobacterial cell wall and pattern recognition receptors on macrophages
    • Persists in macrophage phagosome and inhibits maturation of phagolysosome
    • Proliferates in phagosomal vacuole

    Infection Outcomes

    • Spontaneous healing
    • Containment of the infection (remission)
    • Reactivation and dissemination (progression)

    Predilection Sites

    • M.bovis: lung and lymph nodes of the head and thorax
    • M.avium paratuberculosis: small intestine and mesenteric lymph nodes

    Clinical Signs

    • Weight loss is a common sign of advanced disease
    • Respiratory symptoms (M.bovis)
    • Intestinal dysfunction symptoms (M.avium paratuberculosis)

    Tuberculous Infections in Animals

    • Birds: naturally susceptible to primarily M.avium avium
    • Ruminants:
      • Cattle: M.bovis, commonly progressive with hematogenous dissemination to the liver and kidneys
      • Sheep and goats: susceptible to M.bovis, M.avium paratuberculosis, and M.avium hominissuis
      • Deer: susceptible to M.bovis
    • Dogs and cats:
      • Dogs: M.bovis, lesions resemble foreign body reaction than tubercles
      • Cats: M.avium species, intestinal and abdominal localization
    • Horses: rarely infected, usually with M.avium hominissuis
    • Swine: infection usually via the alimentary route, M.bovis causes progressive disease with classical lesions
    • Wild animals: serve as reservoir for M.bovis

    Nontuberculous Infections

    • Prevalent in the environment, cause opportunistic TB-like infections in animals and humans
    • Infections can cause false positive test results due to cross immune reactions
    • Mostly saprophytic species
    • Opportunistic, granulomatous infections
    • Johne's disease (Paratuberculosis) caused by M.avium paratuberculosis

    Johne's Disease (Paratuberculosis)

    • Chronic, irreversible wasting disease of ruminants
    • Caused by M.avium paratuberculosis
    • Clinically affected and asymptomatic shedders
    • Main route of infection is fecal-oral
    • Signs: reduced milk production, breeding problems, increased incidents of mastitis, early culling, and overall economic losses
    • Lesions: characteristic gross corrugated appearance of intestinal mucosa
    • No cost-effective antimicrobial treatments
    • Prevention and elimination of infected animals is best for overall herd health

    Feline Leprosy Syndrome

    • Chronic, nodular, and ulcerative mycobacterial infection of the skin
    • Several causative species, including M.lepraemurium
    • Common locations of lesions suggest transmission by rodent bites or arthropods
    • Disease is more common in older cats and progresses slowly
    • Lesions: nodules occur in cutis or subcutis, ulceration, and lymph node involvement

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    Bacteriology: Burkholderia, Bordetella, Fusobacterium, Mycobacteria

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