Page 1794 - Cote clinical veterinary advisor dogs and cats 4th

Salmonellosis 899

United States and Sweden and occurs primarily • Persistence and severity of infection depend Acute General Treatment
in cats feeding on songbirds during seasonal on the patient’s immune status. • Mild cases are often self-limited and require
VetBooks.ir ASSOCIATED DISORDERS DIAGNOSIS • IV fluid support, including plasma or colloids Diseases and Disorders
only supportive therapy and good hygiene
migrations.
to prevent contagion or zoonotic infection.
Focal organ infections can be found anywhere
or septicemia (p. 907).
but especially likely are: Diagnostic Overview if necessary, is recommended for dehydration
Diagnosis is suspected in animals with acute
• Abscesses, pneumonia, pyothorax or chronic GI illness, especially if young, • Antibiotic therapy is controversial.
• Meningitis immunocompromised, or eating raw meat diets. ○ May induce a carrier state and prolong
• Osteomyelitis Diagnosis is based on isolation of Salmonella fecal shedding of organisms
• In utero infection resulting in abortion, from feces, blood, or infected tissues. Because ○ May induce drug-resistant strains while
stillbirth, weak puppies or kittens prevalence of organism is similar in stool from suppressing endogenous (beneficial) flora
• Acute hepatic necrosis and associated hepatic healthy and diarrheic animals, diagnosis must be ○ Antibiotics are indicated if the patient is
failure made in conjunction with appropriate clinical febrile, evidence of sepsis or SIRS exists,
signs. the patient is immunocompromised and
Clinical Presentation shows GI signs, or blood cultures are
DISEASE FORMS/SUBTYPES Differential Diagnosis positive.
• Up to 30% of dogs and 18% of cats are • Diarrhea due to other causes (p. 1213) ○ Combination of enrofloxacin 5-10 mg/kg
subclinical carriers. • Septicemia due to other causes (p. 907) PO or slow IV q 24h in dogs or 5 mg/
• Primarily acute enterocolitis kg PO or slow IV q 24h in cats and
• Chronic diarrhea rare Initial Database amoxicillin or ampicillin 10-20 mg/kg
• Septicemia/endotoxemia • CBC, biochemistry profile, and coagulation PO or IV q 8h is advocated as empirical
• Localized infections (see Associated Disorders) changes are generally nonspecific or represent therapy but ideally should be based on
• Cats may develop chronic, febrile illness signs of endotoxemia/sepsis. susceptibility testing.
(songbird fever) ○ Neutropenia with left shift and toxic ○ Others reported to be effective include
neutrophils in acute phase or systemic trimethoprim-sulfadiazine 15 mg/kg PO
HISTORY, CHIEF COMPLAINT disease q 12h or chloramphenicol.
Animals can appear healthy or have signs of ○ Neutrophilia if chronic illness ○ Antibiotic therapy should initially be
illness related to localized infection or sepsis. ○ Nonregenerative, possibly hypochromic administered for 10 days, but some cases
The most common historical findings of illness anemia may be noted. may require longer-term administration.
due to salmonellosis are GI-related: watery to ○ Thrombocytopenia in severe cases, with
mucoid diarrhea with or without blood, straining septicemia leading to DIC Recommended Monitoring
or increased urgency to defecate, vomiting, ○ Prolonged coagulation times in severe cases Monitor carefully for signs of sepsis (p. 907)
anorexia, lethargy/depression, and weight loss with DIC or SIRS.
○ Hypoproteinemia due to GI loss
PHYSICAL EXAM FINDINGS ○ Sometimes hyponatremia and hyperkale- PROGNOSIS & OUTCOME
Exam can be normal, or findings can reflect mia (similar to hypoadrenocorticism)
GI, localized, or systemic infection: ○ Hypoglycemia, azotemia, or hyperbiliru- • Prognosis for mild cases is good; infections
• Fever binemia suggests endotoxemia/sepsis. usually resolve spontaneously or with sup-
• Abdominal pain • Fecal flotation, culture, and ELISA testing as portive care only.
• Dehydration, possibly severe needed to rule out other causes of diarrhea. • Prognosis for septicemic patients is guarded;
• Pale mucous membranes, tachycardia, tachy- potential disease complications include
pnea, weakness, weak pulses if septicemic Advanced or Confirmatory Testing electrolyte imbalances, septic shock, SIRS,
• Conjunctivitis in cats • Fecal bacterial culture and DIC.
○ Best results using enrichment broth or
Etiology and Pathophysiology selective culture media PEARLS & CONSIDERATIONS
• Salmonella spp: gram-negative, facultative ○ Positive fecal culture establishes infection
anaerobic, motile, non–spore-forming rods but does not necessarily confirm that signs Comments
from the family Enterobacteriaceae are due to salmonellosis because subclinical Patients fed raw food diets are at increased risk
• Ubiquitous, most commonly transmitted carriers are common. for salmonellosis.
through contact with contaminated food, ○ False-negative results are possible because • Salmonella isolated from 66%-80% of
water, or fomites the organism grows fastidiously. samples of raw food (e.g., bones, raw food
• Bacterium survives for up to 6 weeks in • Fecal polymerase chain reaction (PCR) may [BARF] diet)
environment. improve sensitivity of detection. • Salmonella isolated from 30%-93% of stool
• Clinical signs occur secondary to mucosal • Blood culture or culture from other infected samples from dogs fed BARF diets; there is
invasion and epithelial injury. sites; positive culture from blood, bile, or an increased risk for human exposure and
○ Salmonella spp also produce an entero- other normally sterile samples strongly infection.
toxin, resulting in secretory diarrhea. indicative of salmonellosis.
• Organism persists in phagocytic cells of Prevention
intestinal mucosa and mesenteric lymph TREATMENT • Avoid feeding raw or undercooked meat
nodes, liver, and spleen: diets.
○ Results in persistent shedding for 3-6 Treatment Overview • Isolate infected animals, and practice good
weeks after infection For uncomplicated gastroenteritis, treatment hygiene.
• Bacteremia and endotoxemia may occur consists of supportive care without antibiotics.
secondary to mucosal invasion, resulting in For systemic disease or immunocompromised Technician Tips
systemic infection, disseminated intravascular patients, aggressive therapy with antibiotic use • Contact precautions should be taken to avoid
coagulation (DIC), and/or systemic inflam- is warranted. No therapy is recommended for spread between infected patients and other
matory response syndrome (SIRS). subclinical carriers. hospitalized patients or personnel.

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