Septicemia and peritonitis in a colony of common marmosets (Callithrix jacchus) secondary to Klebsiella pneumoniae infection

Six common marmosets from a colony of 50 died over a period of 3 weeks, with the predominant finding of gram-negative bacterial septicemia. Four of these animals died peracutely; the other two were found when they were moribund, and they subsequently died despite clinical intervention. Gram-negative bacterial rods were present in the blood vessels of stained tissues from five of the six marmosets. Three marmosets also had severe fibrinopurulent peritonitis. In addition, one of the marmosets with peritonitis also had purulent mesenteric lymphadenitis with large colonies of gram-negative bacterial rods within dialated colonic crypts. Klebsiella pneumoniae was isolated from multiple organs in three of the marmosets. Clinical evaluation of the entire colony identified four marmosets with anorexia, nasopharyngeal discharge and diarrhea. These marmosets were treated with enrofloxacin immediately, and they responded well. K. pneumonia could not be cultured from nasal or fecal samples obtained from the colony animals. Because of the peracute nature of the disease, animals often die before exhibiting clinical symptoms, and antibiotics are seldom helpful. In this outbreak we saw both of the major forms of Klebsiella infection in common marmosets: the peracute form with bacteremia and minimal inflammatory reaction around blood vessels, and the chronic form with bacteremia, fibrinopurulent peritonitis, and mesenteric lymphadenitis.