Yersinia enterocolitica: pathogenesis, virulence and antimicrobial resistance.

Yersinia enterocolitica is a heterogeneous group of strains, which are classified into 6 biogroups, and into more than 57 O serogroups. However, the human pathogenic strains most frequently isolated worldwide belong to serogroups O:3, O:5,27, O:8 and O:9. The major route of Y. enterocolitica infection is through contaminated foods or water. The primary pathogenic event is colonization of the intestinal tract where most of the pathologic effects and clinical manifestations occur. Temperature and calcium concentration regulate expression of virulence factors that guide the invading yersiniae and allow them to survive and disseminate. Gastrointestinal infections are usually self-limiting and do not merit antimicrobial therapy. Nonetheless, fluoroquinolones or third generation cephalosporins, the best therapeutic options, are warranted to treat enterocolitis in compromised hosts and in patients with septicemia or invasive infection, in which the mortality can be as high as 50%. A review of the pathogenesis, virulence and antimicrobial resistance is carried out.