Filamentous Bacteria Flashcards
Filamentous bacteria clinical importance
Filamentous/ diphtheroid rod form
Wrinkled/ fuzzy colonies
Manifestation of Pyogranulomatous inflammation
Actinomyces characteristics
Oral flora, GIT and UGT
Strict/ facultative anaerobes
Non-spore forming, gram +, non-acid fast
Actinomyces
Require rich media for growth/ capnophilic
Killed by disinfectants, penicillin, fluroquinolones
Endogenous infections caused by commensal/ bites
Actinomyces pathogenesis
Triggers suppurative responses in immediate vicinity
Peripheral granulation, mononuclear infiltration, fibrosis
Exudate with yellow sulphur granuales/ rosettes
Ruminants infected with Actinomyces
A. bovis and A. israelii
Following trauma → lumpy jaw/ chronic osteomyelitis
Pulmonary infection in cattle
Actinomyces CS in ruminants
Porous bone with pus replacing normal bone
Teeth dislodgment, inability to chew, mandible fracture
Actinomyces infection in horses
A. bovis and A. denticolens
Isolated from abscesses, corneal swabs and skin pustules
Fistulous withers (saddle sores) and Brucella spp.
Actinomyces infection in dogs and cats
A bovis, A. hordeovulneris and A. viscous
Pyogranulomatous infections under the skin and body cavities
Actinomycotic discospondylitis/ foxtail grass
Actinomyces infection in swine
A. suis
Mastitis
Recovered from lung lesion and aborted fetuses
Diagnosing actinomyces
Aspiration
Granule/ tissue for Gr/AF stain for microscopic smears or culture
Exudate for yellow sulphur granules
qPCR-rRNA uring DNA primers
Lumpy jaw
Actinomycosis
Formation of hard tumor-like masses in the tongue
Caused by A. lingnieresii
Actinomyces treatment and control
Surgery, drainage and iodine therapy
Penicillin
Nocardia characteristics
Gram+, partially acid-fast, saprophytic, nonmotile
Polymorphic rods or cocci
Ubiquitous (soil and water)
Aerobic
Where are nocardia found?
Mammals, fish, mollusks, and birds
Nocardia transmission
Inhalation, direct contact (trauma) and infection
Bovine mastitis in contaminated equipment
Nocardia species
N. asteroides complex (farcinica, nova, transvalensis)- most common
N. brasiliensis
N. otiditiscavarium
Important nocardia diseases
Pulmonary nocardiosis and mycetoma
Nocardiosis in ruminants
Bovine mastitis
Fistulous tracts discharge, lymphadenopathy
Norcardiosis in horses
Mycetoma, pulmonary infection and abortion
Nocardiosis in dogs and cats
Pneumonia and suppurative pleuritis with empyema
Co-infection with distemper
Cutaneous and SQ abscess (cats)
High mortality rate
Canine nocardiosis
Fluctant masses from otitidiscavarium
Develop mycetomas (tumor like mass of fungal mycelia)
Lyphadenitis
Nocardia infection diagnosis
Partial acid-fast/ gram stain
Nocardia treatment
Antimicrobial therapy and control
Trimethoprim-sulfonamid therapy
Fluoroquinolones
Dermatophilus causes …..
Dermatophilosis
Streptothrichosis in cattle
Lumpy wool, strawberry foot rot in sheep
Rain rot or grease heal in horse
Dermatophilosis
Caused by D. congolensis
Dense scabs on skin, exudative lesions
Dermatophilus characteristics
Gram+, motile flagellate coccoid “zoospore”
Facultative anaerobic capnophilic
White grey to yellow colonies
High hemolytic
Obligate parasite CAN’T multiply saprophytically
Dermatophilus transmission
Direct physical contact. stinging arthropods (ticks, flies)
Moist conditions
Dermatophilus risk factors
Ticks of amblyomma genus
Tropical regions (cattle most susceptible)
Intemperate regions (sheep, horses)
Dermatophilus pathogenesis
Invades the epidermis
Neutrophils under infected epidermis → scab
↑ PMNs
Dermatophilus diagnosis
Gram/ Giemsa stain of scab
Florescent Ab in skin debris
Culture
Treatment of Dermatophilus
Acute cases self limiting
Severe: penicillin, streptomycin, tetracycline, chloramphenicol
Long acting enrofloxacin*
Streptobacillus
Rat-bite fever or haverhill fever
Facultative anaerobe
Gram-, nonmotile, non-spore, pleomorphic
Streptobacillus species
One spp is pathogenic/ zoonotic
S. moniliformis (USA) and minus (Asia)
Reservoir: rodents pharynx/ rat
Streptobacillus transmission
Bite or ingestion of contaminated food or water by rat excrement
Streptobacillus patheogenesis
Joint and LN swelling to bronchopneumonia
Abscess in liver and septicemia
L-form relapses with treatmen
Streptobacillus diagnosis
Culture
Puffball appearance (gray mucoid colonies)
Direct fluorescent Ab test
PCR and ELISA
Streptobacillus treatment
Penicillin or tetracycline in pen-allergic
Resistant to cephalosporins and aminoglycosides
