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Year 2 Small Animal ID > Dog/ Cat Bacterial Infections > Flashcards

Flashcards in Dog/ Cat Bacterial Infections Deck (43)
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Common themes of bacterial infections

• Often secondary, If diagnose often need to find out what the primary is
• Isolation does not necessarily equate to clinical relevance.
• Sometimes difficult to interpret a positive result.
• Carriers – clinically normal animals, shedding bacteria
• Antibacterial resistance must be considered.
– is treatment of bacteria always necessary?
• Often not species specific raising questions of zoonosis (and reverse zoonosis).


BActerial infections of dogs

• Salmonella
• Campylobacter
• E.coli
• Leptospirosis
• Borrelia
• Staph
• Ehrlichia
• Tetanus – talk about last 3 another day as primarily in relation to other species
• Botulism
• Brucella


Facts about salmonella

1. BActeria
2. Gram negative
3. Family enterobacteriaceae
4. Infect wide range of animals, birds and reptiles
5. Gasteroenteritis in humans
6. Food borne most common transmission
• Carried by healthy animals – reservoir (carry without showing symptoms of infection
• Dogs, cats & reptiles – turtles, lizards, snakes, frogs etc – leave salmonella traces in through house if left to free-reign, faeces.
o 10-100% reptiles can shed it
• High incidence in young children  due to them testing things with mouths etc
• Outbreak linked to feeder mice


what is illness from salmonella called?



Talk about salmonellosis
infection vs disease?
Lots of serovars?

• Infection much more common than disease
– 1-5% normal cats shedding
– up to 25% dogs < 6 months old
• Possible cause of ‘garbage guts syndrome’ in puppies and kittens (e.g. from food or wild birds/rodents).
• Wide range of serovars involved (whatever is local) mostly belonging to Salmonella enterica subspecies enterica...


How is salmonella transmitted?

• indirect: Ingestion of contaminated (raw) food, water or fomites (contaminated by infected faeces)
• Direct contact with an infected animal or human (less common)


What are clinical signs of salmonellosis?

1. Pyrexia
2. Anorexia
3. Vomiting and diarrhoae
4. Abdominal pain
5. Bacteraemia
6. Abortion. stillbirth
7. Severe disease in some individuals


How do you diagnose salmonellosis?

• Isolation of Salmonella from faeces
• Infected dogs shed for 4 to 6 weeks – some become carriers


How do you treat salmonellosis?

1. Local GI disease (a bit unwell, little diarrhoea) DO NOT USE ANTIBACTERIALS
a) risk of inc AMR
b) evidence that antibacterial use can prolonge shedding
c) let the animal clear the infection. Monitor this by repeat samples
2. BActeraemia requires antibacterial therapy - minority of cases
a) Suggested antibiotics - trimethoprim and sulphonamide, amoxycillin), do sensitivity tests to make sure get correct antibac first time


Name of disease caused by campylobacter bacteria



What type in humans, and dogs?

• In humans mainly C. jejuni (poultry associated most typically) but also C. coli and others
• In dogs mainly C.upsaliensis
• Common with no clinical signs


what is it usually a result of?
What to be aware of?

• Probably secondary or opportunistic pathogens
• Diagnosis: fresh fecal material, special transport and growth media
• Treatment: supportive, like salmonella.
• Potentially zoonotic (relatively rare but if immunocompromsied be more aware)


E coli

• Normal gut flora, certain types can cause damage = toxin producing
• Enteropathogenic E.coli – toxin production
• Commonly use production of Haemolysins as measure of potential significance.
• Isolating E coli from fecal sample is normal but if cultures on blood agar, around colony lysis of blood cells = E coli producing harmolysin and so clinically more significant


Leptospirosis about

• Mobile spirochaete
• Affects humans & a wide range of animals (not species specific) , including mammals, birds, amphibians, and reptiles


Most common serovars of lepto in dogs:

– Leptospira icterohaemorrhagiae
– Leptospira canicola
– Leptospira grippotyphosa


How is lepto transmitted? What about humans?

• Generally urine transmitted
• Relatively rare in humans


Pathogenesis of lepto

• Direct or indirect contact with urine of infected animals
– Including contaminated water or soil
• Penetration through mucous membranes
• Multiplication in blood
• Spread to whole range of tissues – kidney (into urine then passed to next animal), liver (common CS jaundice), spleen, CNS, eyes and genital tract
• Organisms cleared from most tissues but persist in kidneys with renal excretion for weeks/months (carriers).


Clinical signs of lepto in dogs

• Severity depends on serovar, age and immunity of host
• Acute (severe)
– pyrexia, vomiting, shock, haemorrhage, jaundice, renal failure
• Sub-acute
– pyrexia, PUPD, petechia (pin point round spot as result of bleeding, severe = haemorrhage), jaundice


Diagnosis of lepto in dogs

• History and clinical signs
• Serology (titre > 1in 800; or a fourfold rise in titres)
• Detection of spirochaetes in urine sample; fluorescent antibody
• PCR detection of leptospira


Treatment of lepto in dogs

• Supportive treatment e.g fluid replacement – animals often very ill when arrive
• Penicillin – clears bacteraemia
• Tetracycline or doxycycline to eliminate organisms from carrier dogs
• Zoonotic implications – make owner aware, need to keep infected animal in an environment for fairly long period of time while it is SHEDDING spirochetes
• Why most dogs are vaccinated


Prevention of lepto

• Vaccination – does not necessarily protect against all serovars
– Considerable debate about what are the right serovars to include in vaccines.
• L2 vaccines historically
• L4 vaccines some now have
• Eliminate organism from carrier animals
• Prevent contact with reservoir hosts (rodents in this context)


Borrelia burgdorferi:

– Lyme disease
– Likely very rare in UK pets
– Massive public awareness in humans
– Tick transmitted
– Zoonosis (but unlikely owner to get from infected pet)
– Clinical signs in animals: ?lameness, lymphadenopathy
– Anti-parasite companies use it as part of the drive tick prevention



• Gram-positive bacteria
• Commensals of skin of man and animals


Staphylococcus pseudintermedius

• Mucosal commensal and opportunistic pathogen
• Most common organism associated with canine pyoderma.
• ( multidrug-resistant bacterial pathogens) MRSP isolates now considered worldwide. ☹
• MRSP usually show MDR
• MRSP carriage in healthy dogs (0-4.5%) and cats (1.2-4%).
• Rare zoonosis in the immunocompromised people
Opportunistic: infection only occurs due to a primary underlying cause that disrupts the balance between host-defences and microbiota.
Typically skin and ear infections (surface, superficial and deep pyoderma), traumatic and post-surgical wound infections, possibly complicated by implants, suture material and biofilm


Diagnosis of Staphylococcus

• Staph pyoderma: cytology.
– degenerative neutrophils with intracellular coccoid bacteria in pairs or groups.
• MRSP: culture and susceptibility testing.
• The carriage or infection risk increases with administration of antimicrobials, surgery, hospitalisation or frequent veterinary premises contact.


Control of staph

HAND HYGEINE is the single most effective


Treatment Staphylococcus

• Often secondary infection
• Investigation and treatment of the underlying disease is paramount for a successful outcome.
• Superficial pyoderma cases, topical therapy alone is recommended.
– 2-4% chlorhexidine (shampoo, sprays, wet wipes and mousse)
• Severe/ widespread superficial pyoderma or deep pyoderma.
– Systemic antibiotics based on culture
– seek specialist advice


Opportunistic infections with Staphylococcus .aureus

• S. aureus carried in nares of up to 30% of healthy people
• In humans – food poisoning, pneumonia, skin infections and post-operative wound infections
• In cattle – mastitis
• In dogs and cats – can be associated with skin infections
• Horses – pneumonia



• Meticillin Resistant Staph Aureus – one of the first organisms that got us talking about AMR
• Commensal skin and nasal passages
• Zoonotic potential


MRSA in dogs and cats

• EMRSA (Epidemic strain) 15 and 16
– Dominant types in UK human hospitals
– Also most common in cats and dogs
– Reverse zoonosis
– Believed that cats and dogs are being infected by people who are often in hospitals.