MICROBIO1 EXAM 2 Actinomyces, Dermatophilus, Nocardia, and Corynebacterium; Trueperella, Rhodococcus, Listeria & Erysipelothrix

- highly diverse group of G+ bacteria

- cell morphology is coccoid to filamentous

- rods or filament morophology, often branching

- facultative or obligate anaerobes

- enriched media needed for culture

- opportunistic pathogens

actinomyces

polymicrobal infection

actinomycosis is what type of infection

- oral mucosa

- tooth surfaces (dental plaque)

- mucous membranes of nasopharynx

- urogenital tract

- intestinal tract

most Actinomyces species are commensals of mammals and primarily habitat

pyogranulomatous reactions

What type of reactions are typical in actinomycosis

endogenous

Actinomyces are opportunistic pathogens, so most infections are _______, or come from the host's own microbiota

increased

Pathogenicity of actinomyces in mixed infections is increased or decreased?

sulfur granules

fibrinous tracts of pyogranulomatous lesions from Actinomyces secrete purulent exudate that contains

bacterial filaments surrounded by club-shaped, mineralized calcium phosphate crystals

sulfur granules are made up of what

Actinomyces bovis

- causes lumpy jaw in ruminants, particularly cattle

- indurated, suppurative lesions in soft tissue and bone (mainly mandible)

- abscess may forms and discharge through fistulas

- can cause pulmonary infection but less common

- tooth dislodgement

- inability to chew

- mandibular fractures

osteomylelitis from Actinomyces bovis can cause

- bite wound, course hay or sticks puncturing mouth while eating, erupting teeth

how can cattle get Actinmyces bovis

Actinomyces suis

- causes mastitis and ventral subcutaneous lesions in sows

- occasional infection in lungs, splene, kidneys, and other organs

traumatic inoculation during suckling and weaning

how can sows get Actinomyces suis

Actinomyces viscosus

- Actinomyces species that primarily causes subcutaneous masses in dogs and cats

- can also cause thoracic infections or abdominal and retroperitoneal infections

pyothorax and bite wound abscesses

most common disorders in cats that Actinomyces species is isolated

- clinical presentation

- lumpy jaw

- exudates/aspirates may contain sulfur granules

sulfure granules from Actinoymces

- club shaped colonies with bacterial-sized filaments

- surgery

- prolonged administration of abx

treatment of Actinomyces

- sodium iodide IV with antibiotics

- debridement of bone lesions

- lavage with iodine solution

treatment of Actinomyces bovis (lumpy jaw)

- ensure good oral care

- limit amount of rough forage fed

- protect pets from grass awns

prevention of Actinomycosis

- branching filaments

- produces flagellated (motile) spores

- obligate parasite

- zoonotic

- facultative anaerobe

- capnophilic, grows well on blood agar

Dermatophilus congolensis

direct contact, fomites, and biting arthropods

how is Dermatophilus congolensis transmitted

cattle, sheep, horses

common hosts of Dermatophilus congolensis

asymptomatic chronically infected hosts

main reservoir or Dermatophilus congolensis

- dermatophilosis

- trauma/persistent wetting facilitate invasion of epidermis and hair follicles

- virulence factors (enzymes)

pathogenesis of Dermatophilus congolensis

exudative dermatitis with formation of scabs/crusts

dermatophilosis

- paintbrush lesions of matted hair

clinical manifestations of Dermatophilosis congolensins

- clinical findings plus demonstration of organisms in stained preps from scabs

- isolation/ID via culture or PCR

diagnosis of Dermtophilosis

- grooming and isolation in dry quarters for mild cases

- parenteral antibiotics for severe cases

- topical treatment following grooming for horses

treatment for Dermatophilosis

- isolate/cull clinically affected animals

- minimize skin trauma and exposure to rain and ectoparasites

control/prevention of dermatophilosis

Nocardia

- branching filaments that fragment into rods and cocci

- partially acid fast

- obligate aerobes, grow well on blood agar

- saprophytes

- cause opportunistic infections

soil

reservoir of infection of Nocardiosis

widspread in soil and water

saprophytes

- trauma to skin

- inoculation of teat canal

- inhalation

- ingestion

routes of infection of Nocardia

true

T/F: Nocardia is typically not contagious

- suppurating lesions with variable granulomatous features

- sanguinopurulent exudates that can sometimes contain soft granules

- lymph nodes often involved

- hematogenous dissemination may occur

Nocardiosis

- facultative intracellular organisms

- survive and grow inside of phagocytes

- virulence factors prevent phagocytosis

pathogenesis of nocardia

- mastitis

- pneumonia

- abortion

- abscesses

disease patterns of Nocardia

- gram positive

- partially acid fast bacilli

nocardiosis presumative diagnosis

- culture

- antimicrobial susceptibility testing

nocardiosis definitive diagnosis

cats

which species is reported/identified cases of Nocardiosis more commonly seen in

immunosuppressive disorders

Nocardiosis in dogs and cats is associated with

Corynebacterium

- pleomorphic bacilli, non spore forming

- facultative anaerobes and aerobes, need enriched media

- commensals

- tissue trauma precedes infection/disease and lesions tend to suppurate

- Corynbacterium pseudotuberculosis

- the species of Corynbacterium most often seen in animal infections (small ruminants)

- facultative intracellular pathogen

skin trauma

how does Corynbacterium pseudotuberculosis colonization happen

- phospholipase D

- call wall lipids

virulence factors of Corynbacterium

acts as vasodilator, enhances spread via lymphatic vessels. also causes dermonecrosis, phagocyte toxicity, and other damage

how does phospholipase D act as a virulence factor for Corynbacterium?

protect against lysosomal enzymes of phagocytes, also induce tissue necrosis and abscess formation

how do cell wall lipids act as virulence factors for Corynbacterium

survives, grows in phagocytes

- transported from site of infection to superficial lymph nodes and then to internal lymph nodes and other reticuloendothelial tissues

pathogenesis of Corynbacterium pseudotuberculosis

- caseous lymphadenitis in sheep/goats (onion ring appearance when sectioned)

- chronic infection, may persist for host's life

disease patterns of Corynebacterium pseudotuberculosis

- abscesses in pectoral region (Pigeon fever), ventral abdomen, preputial or mammary regions

- ulcerative lymphangitis

In equids, where does the external form typically shop up in?

pigeon fever from C. pseudotuberculosis

ulcerative lymphangitis from C. pseudotuberculosis

- radiography and ultrasonography to detect abscesses

- serological test to detect antibodies

diagnosis of internal C. psuedotuberculosis

- lance, drain, and lavage external abscesses with antiseptic solution

- may need long term antibiotics

treatment of C. pseudotuberculosis

recurrence is common even with effective antibiotics treatment

what is one thing to keep in mind with treatment of C. pseudotuberculosis

Actinobacteria

Which phylum are Trueperella pyogenes and Rhodococcus equi in

FIrmicutes

Which phylum are Listeria spp. and Erysipelothrix rhusiopathiae in?

- pleomorphic

- gram positive bacilli

- non spore forming

- facultative anaerobes and aerobes, cultured on enriched media

- capnophiles

morphology of Trueperella spp

mucous membranes of mammals

which part of the body are Trueperella spp commensals in?

T. pyogenes

Trueperella species that is of primary importance in veterinary medicine

- coccobacillary to short rods

- club shaped in young cultures

- facultative anaerobe, capnophilic

- grows well on blood agar

T. pyogenes

- upper respiratory

- urogenital

- GI tracts

T. pyogenes is normal inhabitant of which tracts in mammals

endogenous

T. pyogenes are opportunistic pathogens, most infections are

- causes suppurative lesions in many organs/tissues

- abscesses that are often encapsulated, empyema, pyogranulomas

what types of lesions does T. pyogenes cause

hematogenous

how is T. pyogenes spread

- pyolysin O

- Neuraminidase

virulence factors of T. pyogenes

cytotoxic to macrophages, neutrophils, and RBCs

how does T. pyogenes use Pyolysin O as a virulence factor

bind to host cells and extracellular matrix

how does T. pyogenes use Neuraminidase and other adhesins as virulence factors

synergistic pathogen

T. pyogenes acts as a ________ in bovine liver abscesses caused by Fusobacterium necrophorum

septic arthritis

what does T. pyogenes cause in swine

severe mastitis

what does T. pyogenes cause in cattle

- flies

- teat contact with contaminated environment

- contaminated milking equipment

how is T pyogenes transmitted in cattle

- control flies

- disinfect and chemically dry living quarters and calving areas

- treat heifers and dry cows with prophylactic long-acting penicillin

- isolate/cull affected animals

control/prevention of mastitis

- pleomorphic

- gram positive to gram variable

- non spore forming

- aerobes

- saprophytes

Rhodococcus spp

Rhodococcus equi

- cocci, coccobacilli, rods

- readily cultured on blood agar

- opportunisitc pathogen of young foals

soil and intestinal tracts and feces of healthy animals

reservoir of Rhodococcus equi

inhalation or ingestion of virulent strains found in contaminated soil

main routes of infection of Rhodococcus equi

- granulomas, pyogranulomas, and abscesses

- hematogenous dissemination can occur

- survive and grow inside of macrophages (facultative intracellular pathogens)

pathogenesis of Rhodococcus equi

- Vap proteins

- capsule

- mycolic acid

- cholesterol oxidase

what are some virulence factors does Rhodococcus equi have that allows them to survive and grow inside macrophages

pyogranulomatous bronchopneumonia

what does Rhodococcus equi cause in foals, mostl cases happening between 1 and 4 months of age

protective type I immune response

Rhodococcus equi can occur in foals that are lacking

immunodeficient

Rhodococcus equi can infect adult horses that are

submandibular and cervical lymphadenitis

Rhodococcus equi is a common cause of what in swine

gram positive pleomorphic cells within macrophages in smears from tracheal wash, pus from lesions, etc

presumptive diagnosis of Rhodococcus equi

- long term combination therapy

- supportive care

treatment of Rhodococcus equi

- gram positive

- non spore forming coccobacilli

- facultative anaerobes, grow well on blood agar

- saprophytes

Listeria spp

Listeria monocytogenes

spp of Listeria that infects imammals, primarily causes septicemia, abortion, and CNS infections

blood agar with reduced O2 and increased CO2

how is Listeria monocytogenes typically grown

soil, silage, sewer effluent, freshwater habitats, and Gi tracts/feces of many animals

where is Listeria monocytogenes found

ingestion of contaminated food

how is Listeria monocytogenes spread

CNS

where does Listeria monocytogenes have predilection for in the body

vertical transmission

how can Listeria monocytogenes be spread

penetrates intestinal epithelium via transcellular/paracellular routes, spread via lymph nodes and blood to tissue, alternative route to CNS via breaks in oral/nasal mucosae, infects cranial nerves and brain

pathogenesis of Listeria monocytogenes

listeriolysin O

what is an important virulence factor of Listeria monocytogenes

allows bacteria cell to escape phagosome and spread

what does listeriolysin O allow L. monocytogenous to do?

- encephalitis

- abortion (3rd trimester)

- septicemia in neonates

what does listeriosis cause in ruminants

- rare but more likely in young birds

- septicemic form most common with lesions in heart, liver and other abdominal viscera

Listeriosis in poultry

- gram positive rods in smears from infected tissue

diagnosis of listeriosis