B. suis is commonly distributed by domesticated pigs and wild boars (members of sus scrofa). However, it has also been observed to be carried by caribou, reindeer, and domesticated animals such as cats and rabbits. Other members of the brucella species, such as B. canis, are most commonly carried by their respective animal counterparts (in this example, dogs).

Initially, only three species of Brucella were known to cause infertility and reproductive losses in livestock. However, since the early 1960s, at least 7 new species have been identified and researched. As of today, there are currently ten known species of Brucella: B. abortus, B. suis, B. ovis, B. melitensis, B. canis, B. neotomae, B. pinnipedealis, B. ceti, B. microti, and B. inopinata; three of which have the potential to cause pathogenesis in humans.

BSL level: 3

Agar type: Brucella agar; Liver infusion agar

Growth condition: Aerobic

Growth procedure: Methods of culturing Brucella species remain generally the same with minor differences in the type of blood infused into the growth medium. For B. suis, agar plates infused with 5-10% sterile defibrinated blood need to be incubated at 35C for 24-72 hours in an anaerobic atmosphere supplemented with CO2.

Domain: Bacteria

Phylum: Proteobacteria

Class: Alphaproteobacteria

Order: Rhizobiales

Family: Brucellaceae

Genus: Brucella

Species: B. suis

Brucella species are generally gram-negative, faculative coccobacilli. B. suis is no exception.

Possible 16s primers: Nes2, Nes1, Det, Mar, EFQ1

16s primer used: Mar

Melting temperature (forward): 54.8C

Melting temperature (reverse): 55.3C

GC content (forward): 50%

GC content (reverse): 48%

Some members of the brucella species causes brucellosis, which is a bacterial disease that primarily causes reproductive losses in animals. It is considered one of the most common zoophilic infections worldwide, capable of inducing chronic morbidity as well as demanding a complex treatment schedule to eradicate the infection. In humans, brucellosis (also called Mediterranean fever) is contracted by consuming unpasteurized milk, undercooked meat, or coming in contact with an infected animal’s secretions. Contracting brucellosis is preventable by properly handling animal-based products before consumption.

Brucellosis in humans is primarily caused by B. melitensis, B. suis, and B. abortus.

• Chills

• Fever

• Sweating

• Joint, muscle and back pain

• Headaches

• Rashes

In uncomplicated brucellosis cases, a doxycycline-aminoglycoside combination is used as treatment. Alternative regimens include doxycycline-rifampin and doxycycline-cotrimoxazole.

A study conducted in 1999 concluded that human monocytic cells experienced delayed apoptosis when infected with B. suis bacterium through a TNF-a-independent mechanism that does not involve LPS. Cells infected with B. suis became resistant to gamma interferon, which suggested that certain cytotoxic processes were impaired during Brucella infection. This implies that B. suis not only prevents the elimination of infected cells, but additionally prolongs its host cell’s lifespan to its advantage.