Bacterial infections of dogs and cats

What are the common themes of bacterial infections

• Often secondary

• Isolation of bacteria does not equate clinical relevance

• Difficult to interpret positive result

• Carriers

• Antibacterial resistance must be considered

• Often not species specific

What are the bacterial infections of dogs

• Salmonella

• Campylobacter

• E. coli

• Leptospirosis

• Staph

• Ehrlichia

• Tetanus

• Botulism

• Brucella

What is the gram stain classification of bacteria

Gram negative bacteria

What family is Salmonella in

Enterobacteriaceae

Who does Salmonella infect

• Wide range of mammals

• Birds

• Reptiles

• Gastroenteritis in humans

How common is Salmonella infection vs disease in cats and dogs

• Infection is much more common

• 1-5% of normal cats

• Up to 25% of dogs over 6 months may shed Salmonella

What syndrome can Salmonella cause in puppies and kittens and where does it come from

Garbage guts syndrome often from contaminated food or wild birds and rodents

What types of Salmonella are involved in salmonellosis

• A wide range of local serovars and serotypes

• Mostly Salmonella enterica subspecies enterica

How is Salmonella transmitted

• Ingestion of contaminated food, water or fomites

• Direct contact with an infected animal or human

What are the clinical signs of Salmonella

• Pyrexia

• Anorexia

• Vomiting

• Diarrhoea

• Abdominal pain

• Bacteraemia

• Abortion

• Still birth

How do you diagnose Salmonella infection

1. Isolate Salmonella from faeces

2. Infected dogs shed for 4 to 6 weeks

How is Salmonella treated

• Do not use antibacterials for local GI disease

• Bacteraemia requires antibacterial therapy

• Trimethoprim, sulphonamide. amoxycillin

• Do sensitivity tests

What species of Campylobacteriosis are in humans

• C. jejuni

• C. coli

What Campylobacteriosis effect dogs

C. upsaliensis

What are the clinical signs of Campylobacteriosis

Common with no clinical signs

How is Campylobacteriosis diagnosed

Fresh material, special transport and growth media

How is Campylobacteriosis treated

Supportive care

Is Campylobacteriosis zoonotic

Potentially zoonotic so request speciation where evidence of transmission

What is E. coli

• Found in normal gut flora

• Enteropathogenic E.coli produces toxins

• Commonly use production of Haemolysins as measure of potential significance

What is Leptospirosis

A mobile spirochaete

Who does Leptospirosis effect

• Humans

• Mammals

• Birds

• Amphibians

• Reptiles

What are the most common serovars of Leptospirosis in dogs

• Leptospira icterohaemorrhagiae

• Leptospira canicola

• Leptospira grippotyphosa

How is Leptospirosis transmitted

Via urine

What is the pathogenesis of Leptospirosis

1. Direct or indirect contact with urine of infected animals

2. Penetration through mucous membranes

3. Multiplication in blood

4. Spread to kidney, liver, spleen, CNS, eyes and genital tract

5. Organisms cleared from most tissues but persist with renal excretion for weeks or months

What are the clinical signs of acute Leptospirosis

• Pyrexia

• Vomiting

• Shock

• Haemorrhage

• Jaundice

• Renal failure

What are the clinical signs of sub-acute Leptospirosis

• Anorexia

• Pyrexia

• PUPD

• Petechia

• Jaundice

How is leptospirosis diagnosed

• History and clinical signs

• Serology

• PCR retection of leptospira

How is Leptospirosis treated

• Supportive treatment such as fluid replacement

• Penicillin clears bacteraemia

• Tetracycline or doxycycline to eliminate organisms from carrier dogs

How is Leptospirosis prevented

• Vaccination does not protect against all serovars

• Eliminate organism from carrier animals

• Prevent contact with reservoir hosts

Who is at risk of getting human leptospirosis

• Vets

• Abattoir workers

• Sewer workers

• Farmers

• Water enthusiasts

How many humans get Leptospirosis

• 102 confirmed cases in 2024

• 75% were male

• 20.6% of cases reported exposure to water source

What does Borrelia burgdorferi cause

Lyme disease

How is Borrelia burgdorferi transmitted

• Tick transmitted

• Zoonotic but unlikely direct from infected pet

What are the symptoms of Borrelia burgdorferi

• Lameness

• Lymphadenopathy

What is the gram stain classification of Staphylococcus

Gram positive bacteria

What is the normal habitat of Staphylococcus species

They are commensals of the skin of humans and animals

What is Staphylococcus pseudintermedius and its clinical importance

A mucosal commensal and opportunistic pathogen, the most common cause of canine pyoderma

What is MRSP and why is it important

• Meticillin-resistant S. pseudintermedius

• Now worldwide and usually multidrug resistant

What is the carriage rate of MRSP

• 0-4.5% in dogs

• 1-2-4% in cats

What is the zoonotic risk of MRSP

Rare zoonosis mainly affecting immunocomprimised people

How is Staphylococcus pseudintermedius diagnosed

• Cytology looking for degenerative neutrophils with intracellular coccoid bacteria in pairs or groups

• Culture and susceptibility testing

What increases the carriage or infection risk of Staphylococcus pseudintermedius

• Administration of antimicrobials

• Surgery

• Hospitilisation

• Frequent veterinary premisis contact

How is Staphylococcus pseudintermedius controlled

Hand hygiene

How is staphylococcus pseudintermedius treated

• 2-4% chlorohexidine by shampoo, sprays, wet wipes and mousse

• Systemic antibiotics based on culture

• Seek specialist advice

Who carriers S. aureus

Carried in nares of up to 30% of healthy people

What causes infection of S. aureus in humans

• Food poisoning

• Pneumonia

• Skin infections

• Post operative wound infections

What causes infection of S. aureus in cattle

Mastitis

What causes infection of S. aureus in dogs and cats

Skin infections

What causes infection of S. aureus in horses

Pneumonia

What is MRSA

• Methicillin Resistant Staph Aureus

• Commensal skin and nasal passages

• Zoonotic potentials

What is EMRSA 15 and 16

• Epidemic strain

• Dominant types in UK human hospitals

• Also most common in cats and dogs

• Reverse zoonosis

How is MRSA treated

• Culture and sensitivity

• Prevent spread

• Decolonisation

What are the BSAVA guidelines on preventing bacterial infection

• Hand hygiene

• Simple uniforms

• Gloves/aprons

• Cover wounds

• Isolation

• Rational use of antibiotics

• Aseptic technique

• Ward cleaning

• Segregation of all waste

• Sterilisation

• Education

What type of pathogen causes ehrlichhiosis

Intracellular bacteria Ehrlichia canis

What form of ehrlichiosis affects dogs

Monocyte ehrlichiosis

In which dogs is ehrlichiosis seen

Traveled dogs only

How is Ehrlichia canis transmitted

Tick borne via Rhypicephalus sanguineus

Which co-infections are commobly seen with ehrlichiosis

Babesia and Leishmaniasis

What is the treatment for ehrlichiosis

Doxycycline

Who does Brucella canis infect

• Exotic in the UK

• Imported dogs from Eastern Europe

• Transmitted between dogs during mating

• People can be infected when handling reproductive tissues

How does Brucella canis affect humans

• Flu like signs, back and joint pain

• Worse in immunocompromised

• Pregnancy risk not proven but some evidence it may lead to adverse outcomes

What are the bacteria infections of cats

• Mycobacteria

• Mycoplasma

• Bartonella

• Abscess

• Actinomycosis

• Nocardiosis

• Tyzzers disease

• Q fever

• Eugonic fermenterr

• Yersinia

What is Mycobacteria

• various species of mycobacteria including tuberculosis

• Zoonotic

• Cutaneous nodules, draining sinuses, panniculitis

How is Mycobacteria diagnosed

By culture

How is Mycobacteria treated

• Rifampicin

• Clarithromycin

• Enrofloxacin

What causes feline infectious anaemia

Mycoplasma haemofelis adheres to erythrocytes causing damage to membranes and removal of RBC in spleen and liver

How is feline infectious anaemia transmitted

By fleas and direct contact

What are the clinical signs of feline infectious anaemia

Often asymptomatic but if cat is stressed or immunocompromised it causes anaemia

How is feline infectious anaemia diagnosed

• Haematology - regenerative anemia, polychromasia, nucleated RBC

• Stain smears with Giemsa or acridine orange - reveals small round dots adherent to RBC

• PCR - more sensitive

How is feline infectious anaemia treated

• Oxytetracycline or doxycycline for 3 weeks, controls but does not eliminate infection

• Prednisilone may help as some cats develop immune mediated haemolytic anaemia

• Blood transfusion

• Check for FeLV and other immunosuppressants

What is Batronella henselae, cat scratch disease

• Caused by a bacterium endemic in cats

• Transmitted by fleas

• Transmitted by humans by scratch, mainly children, initially skin lesion then lymphadenopathy

• Flea control