Definition

• Escherichia coli-Gram-negative member of the Enterobacteriaceae; normal inhabitant of the intestine of most mammals; along with other infectious agents, may increase the severity of parvovirus infections.
• Acute infection of puppies and kittens in the first week of life; characterized by septicemia and multiple organ involvement.
• Isolation from stool of young animals-inconclusive evidence of pathogenic potential because it is normal flora; need to assess virulence potential using molecular methods.
• Isolation from blood cultures or internal organs-constitutes better evidence of causality.
• Infection of older dogs and cats-documented; individual strains poorly characterized in regard to virulence attributes.

Pathophysiology

• Virulence factors-not well defined; likely E. coli as a cause of septicemia in neonatal dogs and cats reflects a balance between immunologic immaturity and intestinal barrier function of the host and resident enteric E. coli rather than a single virulent strain.
• ETEC, AEEC, UPEC, and CNF+ E. coli strains-recovered from dogs.
• Similar E. colis isolated from cats (strains poorly characterized).
• Intestinal strains colonize and multiply in the small intestine; ETEC then elaborates uncharacterized adhesins and enterotoxins (STa); the attaching and effacing factor of AEEC (EAE+).
• Many strains of E. coli from dogs and cats are hemolytic.
• A new type of E. coli has been found in boxer dogs with IBD (granulomatous colitis) characterized by ability to adhere, to invade, and to replicate in macrophages, resulting in a tremendous inflammatory response within the intestinal wall.

Systems Affected

• Neonates-small intestine (enteritis); multiple body systems (septicemia).
• Puppies/kittens and adults-small intestine (enteritis); urogenital (cystitis, endometritis, pyelonephritis, prostatitis); mammary gland (mastitis); large intestine (colitis).

Genetics

Boxer dogs may be predisposed to large bowel colitis.

Incidence/Prevalence

• Few statistics available.
• More common in neonatal puppies and kittens <1 week old that have not received any or adequate amounts of colostrum.
• Problem in overpopulated kennels and catteries.
• Sporadic accounts in older dogs and cats (mainly diarrhea and urogenital problems).
• Purulent skin disease and otitis and meningoencephalomyelitis.

Geographic Distribution

Worldwide

Signalment

Signs

Causes

• E. coli-member of the endogenous microbial flora of the adult's gastrointestinal tract, prepuce, and vagina.
• Many strains isolated from case material are poorly characterized in regard to virulence factors; strains need to be evaluated by molecular methods to assess virulence potential.
• Often found in older dogs and cats concurrently with other infectious agents.

Risk Factors

Differential Diagnosis

• Infectious enteritis-viral: feline panleukopenia, FeLV, FIV, enteric coronavirus, canine parvovirus, rotavirus, canine distemper; bacterial: Salmonella, E. coli, Campylobacter jejuni, Yersinia enterocolitica, bacterial overgrowth syndrome, Clostridium difficile, Clostridium perfringens; parasitic: hookworms, ascarids, whipworms, Strongyloides, Giardia, coccidia, cryptosporidia, rickettsiae (salmon poisoning).
• Dietary-induced enteritis-overeating; abrupt changes; starvation; thirst; food intolerance or allergy; indiscretions (e.g., foreign material or garbage).
• Drug- or toxin-induced enteritis-antimicrobial agents; antineoplastic agents; anthelmintics; heavy metals; organophosphates.
• Extra-intestinal disorders or metabolic diseases-acute pancreatitis; hypoadrenocorticism; liver or kidney disease; pyometra; peritonitis.
• Functional or mechanical ileus-gastric-dilatation volvulus; intussusception; electrolyte disorder; gastrointestinal foreign body.
• Neurologic disorders-vestibular disease; psychogenic such as fear, excitement, pain.
• Fading neonates.

CBC/Biochemistry/Urinalysis

• Few abnormalities noted, owing to rapidity of death in puppies.
• Adults with enteritis may show chemistry abnormality, depending on the state of dehydration.

Diagnostic Procedures

• Antimicrobials-produce false-negative results if used before obtaining bacterial cultures.
• Routine bacterial culture and identification of E. coli from blood (antemortem) or necropsy tissue (bone marrow, heart blood, liver/spleen, brain, mesenteric lymph node) required.
• Appropriate testing of strains-identify adhesins and toxins (by DNA colony hybridization, PCR) in ETEC and VTEC strains.

Pathologic Findings

• Acute enteritis
• Mucosal inflammation of small intestine
• Petechiae and hemorrhagic lesions on serosal surface of gastrointestinal mucosae and all body cavities
• Fibrin on abdominal wall
• Necrosis of liver/spleen

Appropriate Health Care

Acutely ill puppies/kittens-inpatients; good nursing care.

Nursing Care

• Balanced parenteral polyionic isotonic solution (lactated Ringer's)-restore fluid balance.
• Oral hypertonic glucose solution-for secretory diarrhea, as required.

Activity

Acutely ill immature puppies/kittens (bacteremic/septicemic)-restricted activity, cage rest, monitoring, and warmth.

Diet

Puppies-likely to still be nursing when affected; good nursing care needed with bottle-feeding and/or IV nutrients.

Client Education

Neonates-life-threatening with poor prognosis.

Drug(s) Of Choice

• Antimicrobial therapy-septicemia.
• Guided by culture and susceptibility (MIC) testing of E. coli; empiric therapy until results available.
• Amikacin: dog and cat, 20 mg/kg IV q24h.
• Cefazolin: dog and cat, 5–15 mg/kg IV q6–8h.
• Cefoxitin: dog and cat, 30 mg/kg once, then 15 mg/kg IV q4h.
• Enrofloxacin: dog, 10 mg/kg IV q24h; cat, 5 mg/kg IV q24h; avoid use in pregnant, neonatal, or growing animals (medium-sized dogs <8 months of age; large or giant breeds <12–18 months of age) because of cartilage lesions.
• Ticarcillin-clavulanate: dogs and cats, 50 mg/kg PO q6h.

Contraindications

• Fluoroquinolones-enrofloxacin: avoid use in pregnant, neonatal, or growing animals (medium-sized dogs <8 months of age; large or giant breeds <12–18 months of age) because of cartilage lesions.
• Chloramphenicol and trimethoprim-sulfa are likely ineffective for E. coli septicemia.

Precautions

Ensure adequate hydration and perfusion when using aminoglycosides.

Patient Monitoring

• Blood culture-puppies/kittens with fever and/or diarrhea.
• Monitor temperature-with signs of lethargy and/or depression.
• Monitor behavior-eating, drinking, and/or nursing; adequate weight gain.

Prevention/Avoidance

• Bitch/queen-good health; vaccinated; good nutritional status.
• Clean and disinfect parturition environment (1:32 dilution of bleach); clean bedding after birth frequently.
• Ensure adequate colostrum intake of all littermates.
• Separate mother with nursing litter from other cats or dogs.
• Keep the density low in kennel or cattery rooms.
• Wash hands and change clothes and shoes after handling other cats/dogs and before dealing with neonates.

Expected Course and Prognosis

• Neonates-life-threatening; prognosis often poor; neonate may rapidly succumb; quick treatment with supportive care essential for survival.
• Adults-self-limiting with supportive care, depending on the degree of dehydration and existence of other diseases.

Age-Related Factors

Neonates-greatest risk of infection and subsequent septicemia.

Zoonotic Potential

• Little documented information of the virulence potential of E. coli strains from dogs or cats for humans, although recently, similarities have been found between canine fecal and UTI E. coli and human E. coli associated with UTI, sepsis, and meningitis; growing concern for the presence of multidrug resistance determinants in E. coli strains from companion animals.
• Always wash hands after handling animals (especially patients with diarrhea) because of the risk of acquiring other infectious agents (e.g., salmonellae, Giardia).
• Caution: keep children and immunosuppressed persons away from pets with diarrhea.

Synonyms

• E. coli septicemia
• Neonatal enteritis

Abbreviations

• AEEC = attaching and effacing E. coli
• CNF = cytotoxic necrotizing factor
• EAE = experimental autoimmune encephalomyelitis
• EPEC = enteropathogenic E. coli
• ETEC = enterotoxigenic E. coli
• ExPEC = extraintestinal pathogenic E. coli
• FeLV = feline leukemia virus
• FIV = feline immunodeficiency virus
• IBD = inflammatory bowel disease
• MIC = minimal inhibitory concentration
• PCR = polymerase chain reaction
• UPEC = uropathogenic E. coli
• UTI = urinary tract infection
• VTEC = verotoxigenic E. coli

Client Education Handout Available Online