Salmonella

Test codes:
B0040 - Ultrasensitive qualitative detection of Salmonella bacteria by real time polymerase chain reaction
P0015 - Equine GI/diarrhea panel (includes Salmonella and other pathogens)

Salmonella are gram negative bacteria that occur worldwide, inhabiting the intestinal tracts of many species including humans, nonhuman primates, birds, horses, pigs, dogs, cats, rats, mice, hamsters, guinea pigs and other species. The house mouse is of special concern, as it is often a carrier and plays a significant role in spreading human and animal salmonellosis.

There are more than 1600 recognized serotypes of Salmonella. Among these, S. typhimurium and S. enteritidis have been associated most commonly with lab animal colony infections. Some shipments of rhesus and cynomolgus monkeys have been found to include 20% or more salmonella carriers.

According to a recent report (http://www.defra.gov.uk/corporate/vla/science/ documents/science-end-survrep-qtlyw405.pdf), garden bird salmonellosis is the most frequently diagnosed infectious disease among the wild birds submitted to the United Kingdom’s Diseases of Wildlife scheme. The condition is primarily caused by infection with Salmonella typhimurium, although other serotypes have been reported. Environmental contamination by these infected birds can lead to the exposure of other species, notably cats, horses and humans. Animal feed containing contaminated animal byproducts continues to be a source of Salmonella infection, especially in diets containing raw, unpelleted meal.

Humans and animals infected by salmonella bacteria can be asymptomatic, with clinical signs precipitated by stress. Clinical infections may progress to enteritis, septicemia and variable mortality. A high percentage of survivors become carriers. In humans, acute gastroenteritis can result in sudden onset of abdominal pain, diarrhea, nausea, and fever. Septicemia may sometimes develop in humans, especially in immunocompromised patients.

Fecal and blood culture with selective media have been used to identify salmonella. However, salmonella identification by culture has relatively low sensitivity and is quite slow. Molecular detection of these bacteria, on the other hand, is a highly sensitive and specific technique, and is also more tolerant of suboptimal specimen shipping and handling conditions.

Utilities:

• Confirm the disease causing agent
• Shorten the time required to confirm a clinical diagnosis of Salmonella infection
• Ensure that herds are free of Salmonella
• Early prevention of spread of these bacteria
• Minimize human exposure to these bacteria
• Safety monitoring of biological products that derive from horses

Specimen requirements: Preferred specimens: rectal swab, 1 ml feces or bacterial culture. Less preferred specimen: 1 ml whole blood in EDTA (purple top) or ACD (yellow top) tube. Ship fresh specimens overnight at room temperature.

For specimen types other than those listed here, please call to confirm specimen acceptability and shipping instructions.

For all specimen types, if there will be a delay in shipping, or during very warm weather, refrigerate specimens until shipped and ship with a cold pack unless more stringent shipping requirements are specified. Frozen specimens should be shipped so as to remain frozen in transit. See shipping instructions for more information.

Turnaround time: 2 business days

Methodology: Qualitative real time PCR

Normal range: Nondetected