Enteric Gram-neg (part 2) Flashcards
Genus Salmonella
Doesn’t ferment lactose, produces H2S
Motile by peritrichous flagella
O, H and Vi antigens
Which two species of salmonella aren’t motile?
S. Gallinarum and S. Pullorum
Vi antigen
Isn’t anti-phagocytic
Important virulence factor for S. Typhi
How many serotypes of salmonella are there?
Over 2200, named after the city they were isolated (S. Hartford, S. Newport, etc.)
How many serovars are there?
Nearly 2500 based on Kauffman-White scheme
H and O antigens determine the serovars
S. enterica
Divided into 7 subspecies causing disease in humans and other warm-blood animals
What are the subspecies of S. enterica?
S. Typhimurium (humans), Typhi (poultry), Enteritidis, Abortusovis, Choleraesuis, Dublin (cattle, young animals), Gallinarum and Pullorum
Where are S. enterica found?
Gi of warm and cold-blood animals
Are animals within S. enterica host adapted?
Some: Abortus-equi, abortus-ovis, choleraesuis in swine
Some aren’t: Newport, Anatum, Typhimurium
S. enterica transmission
Fecal-oral route
Infection depends on type of species, host immune status and infectious dose
Clinical manifestation of Salmonellosis
Diarrhea
BUT depending on the strain and dose it may manifest septicemia
Host factors of S. enterica
Age, immune status, concurrent disease, composition of normal flora (provide resistance to colonization)
Pathogenesis of S.enterica
- Adhesion to intestinal epith.
- Invasion via M CELLS OF PEYER’S PATCHES (ileum)
- Intestine and epith. cells engulfment OR directly taken up by DENDRITIC cells from submucosa
- Salmonella localized within the salmonella containing vacuums in cytoplasm
- SCVs transytose salmonella cells to submucosa
- Salmonella internalized within phagocytes (in SCV)
- Infected phagocytes disseminate through lymph and bloodstream –> SEPTICEMIA
What are young animals prone to with salmonellosis?
Enteritis and septicemia form
What are adut animals prone to with salmonellosis?
Acute enteritis
Chronic enteritis (in growing pigs and occasionally in cattle)
Pregnant animals may abort (septicemia)
Salmonellosis in dogs and cats
Infrequent and characterized by acute diarrhea
Disease patterns of salmonellosis
Intestinal lesions of fibrinosuppurative nercotizing and hemorrhagic inflammation of distal small intestine (common in cattle and swine)
Multifocal liver necrosis
Disease patterns in the septicemic form of salmonellosis
Fibrinoid change in BVs, vasculitis, thromboembolism, hemorrhage and infaracts
Salmonellosis in ruminants
Affects neonatal, young and adult cattle
Septicemic or limited to enteritis
Calves may have pneumonia (S. Dublin)
S. Dublin, Newport and Typhimurium are commonly isolated from cattle
Salmonellosis in swine
Acute, fulminating septicemia or chronic debilitating disease
With septicemic S. Choleraesuis: enlarged spleen (hypermia), dark blue ears (thrombosis) and venous congestion
S. typhimurium and S. choleraesuis predominant
Salmonellosis in horses
Diarrhea with occasional septicemia
Colic, GI surgery and antimicrobial agent
S. Typhimurium and S. Anatum are common isolates
Salmonellosis in poultry
Paratyphoid
Pullorum disease
Fowl typhoid
Paratyphoid
Caused by motile serovars in first 2 weeks of life presented by septicemia
True paratyphoid caused by S. paratyphi in humans
Pullorum disease
Causes by S. pullorum
Eradicated from the US
Infects ova of chicken and turkey so embyro infected when egg is hatched
Chickens 2-3 weeks of age die to septicemia
Fowl typhoid
Caused by S. Gallinarum
Acute and chronic disease of domesticated adult chicken
Rare in the US
Competitive flora
Competitive flora helps reduces the #s of Salmonella by competeing for nutrients, masking receptors and producing toxic compounds –> COMPETITIVE EXCLUSION
Diagnosis of salmonella
Fecal sample in intestinal and blood systemic salmonellosis for culture (MacConkey and XLD)
PCR
Treatment for salmonellosis
Enteric: Nursing
Septicemic: nursing care and antibiotics
Endotoxemia: administering serum with Abs to the core LPS (endotoxin)
Control and prevention of salmonellosis
Monitor breeder flocks
Public health and hygiene to prevent human salmonellosis
Competitive exclusion
Genus Yersinia
Gram-neg, cocco-bacilli
Most species flagellated @ ambient temp
7 species: Y. pestis, ruckeri, enterocolitica, pseudotuberculosis, intermedia, kristensenii, frederikensii
Y. Pestis
Non-motile and resembles safety pin of Wright’s Giemsa or Wayson stains
Causes plague (rodent based zoonotic)
Which animals are infected with Yersinia naturally?
Lagomorphs, felids, canids, mustelids and ungulates
How is the Yersinia disease manifested?
Local lymphadentits (bubonic plague)
Pneumonia (pneumonic plague)
Septicemia (speticemic plague)
Sylvatic plague transmitted by arthropod bite
Cat & the plague
Fleas bite via lymphatic, regional LN
Nodular necrosis, suppuration, hemorrhage, edema, fibrin, acute necrotizing inflammation
Bubonic form most common
Pneumonic plague via inhalation of aerosol
Feline plague is rapidly progressing febrile illness
Bubonic plague in europe
1352 25 million dead
Killed 40% of european pop in 14th century
10 million in asia in first half of 20th century
Plague based weapon
Category A biological agent
Weapon delievered by aerosol –> severe acquired pneumonia
Pestis: septic shock and death without early treatment
Plague in the USA
Endemic in western USA causes servile human cases annually (reemerging zoonotic)
Humans get it from fleabite, aerosol or infected cats
Y. pseudotubersulosis
Rodent pathogen that causes abdominal pain in humans without diarrhea
Starlings, grackles and other birds are reservoirs, dogs and cats infected via predation
Pseudotuberculosis
In guinea pigs, cats and turkeys
In small animals, begins as a caseous abscess in mesenteric LN spreading to liver, spleen, etc.
Y. enterocolitica
Psychorphilic organism that has mediated infection via blood transfusion
Humans: high or low virulence
Several thousand cases of food-borne illness in US
Zoonotic
Y. enterocolitica in swine
Principal reservoir for virulent strains of Y. enterocolitica (from tonsils and tongues of healthy animals)
Y. ruckeri
Red-mouth of salmon and trout
Responsible for fatal piscine septicemia
Diagnosis of Yersinia
History
Gram stain -flourescent Ab test of F1 Ag
PCR and DNA sequencing
CIN selective media and cold enrichment for Y. enterocolitica
Prevention and control of Yersinia
Rapid antibiotic therapy (plague)
Streptomycin for human, gentamycin and tetracycline
Hospitalize pneumonic animals
Flea and rodent control
F1 and V subunit vx
Cleaning and cooking pork
Genus Klebsiella characteristics
Gram-neg bacilli, short, non-motile, capsulate
Opportunistic
3 species: K. pneomoniae, oxytoca, granulomatis
K. pneumoniae subspecies
Pneumoniae, ozaenae and rhinoscleromatis
(animal pathogens)
Genus Klebsiella disease
Common in nature, surface water, sewage, soil and plant material
Commensals of mammalian intestinal tract
What is KNN associated with?
Bovine mastitis, equine mastitis, navel ill/ joint ill, neonatal sepitcemia in foals calves and kids
Acquire extended spectrum of B-actaase resistance
Common characteristic of KNN and K. oxytoca
Opportunistic of equine repro tract and important of birds
Pathogenesis of Genus Klebsiella
Virulence factors: capsule, endotoxin and adhesions
Diagnosis Genus Klebsiella
Muccoid colonies are indicative of capsule production
Genus Klebsiella prevention and control
Don’t bed animals on sawdust or wood shavings
Improved hand washing and sterilization to prevent nosocomial infection
