Bacterial Infections of Dogs and Cats

There are many infections of the dog and cat of bacterial origin. The most well known ones will be leptospirosis and bordatella bronchiseptica. Bordatella as a respiratory pathogen will not be covered in this blog post. However, there are many other bacterial pathogens that we do not naturally associate with disease in dogs and cats.

Salmonella

Primarily a disease we associate with chickens. 

In dogs, infection is more common than disease. 25% dogs are carriers below 6 months old, and 1-5% cats. They will shed the virus for around 4-6 weeks. The most common species isolate is salmonella typhimurium. 

• Typically of salmonella the route of transmission is faecal oral/direct contact. 
• Clinical signs, if any, generally appear subclinically. Therese vary from non specific signs such as vomiting and diarrhoea to bacteraemia, abortions and stillbirths. 

Diagnosis generally requires faecal isolation. For GI disease the use of antibacterials is NOT reccomended, although bacteraemia in the blood needs to be treated with antibacterials. Sensitivity tests should be done on antibiotics such as sulphonamides or trimethoprims. 

Campylobacter

Another disease we generally associate with chickens. Zoonosis. C.Upsaliensis most common pathogen. Opportunistic/secondary pathogens include C.Jejuni in conjunction with Canine Coronavirus which can result in severe GI disease 

Diagnosis requires fresh material, and special transport in growth media. Treatment involves supportive therapy.

Leptospirosis

Three species- canicola, icterohaemorrhagiae and grippotyphosa.

Wild and domestic subclincial reservoirs.

Pathogenesis:

1. Entry via mucous membranes/abrasions.
2. Leptospiraemia.
3. Kidney, liver, CNS, spleen, eyes and genital tract localisation.
4. Persists in the renal tubules.

Clinical Signs:

• Peracute sudden death.
• Pyrexia/anorexia.
• Vomiting.
• Icterus.
• Acute renal failure (anuria/oliguria). 

Diagnosis:

• Serology- titre about 1/800.
• Spirochetes in urine- flourescent ab.
• leptospira PCR detection.

Treatment:

• Supportive fluid.
• Penicillin- bacteraemia. 
• Doxycycline- eliminates carrier status.
• Zoonotic.

Prevention:

• Prevent contact with reservoir hosts.
• Eliminate infection from carrier animals.
• VACCINE- does not protect against all serovars. 

Other Disease Affecting Dogs

E.Coli- Enteropathogenic E.Coli Toxins.

Borrelia Burgdorferi- reverse zoonosis. Lameness with lymphadenopathy. 

MRSA- zoonotic. Commensal in the nasal and skin passages. Prevent spread and decolonise EMRSA 15+16. Treat via culture and sensitivities.

Ehrliciosis- monocytic. Travelled dogs- R.Sanguineus. Coinfection with babesia and leishmania. Doxycycline treatment. 

Bacterial Infections of Cats

Mycobacterium

• Zoonotic.
• Cutaneous nodules, draining sinuses and panniculitis.
• Culture diagnosis.
• Treatment with rifampicin/enrofloxacin.

Feline Infectious Anaemia

• MYCOPLASMA HAEMOFELIS
• Transmitted by fleas or vertically.
• Usually asymptomatic but can cause anaemia through stress/immunosuppression.

Clinical Signs:

• Anaemia.
• Splenomegaly.
• Pyrexia.
• Severe haemolysis= jaundice.
• Cyclical- 3-8 week replication.

Diagnosis:

• Haematology- regenerative anaemia, polychromasia and nucleated RBC.
• Giemsa smear- red dots adherent to RBC. (Smear can appear negative with antibiotics). 

Treat:

Oxytetracycline/doxycycline. 

• 3 weeks- does not eliminate infection.
• Prednisolone as some cats can develop autoimmune haemolytic anaemia.
• Check for underlying inmunosuppression e.g. FeLV (trigger).