ISOLATION AND IDENTIFICATION OF SALMONELLA IN A LOHMANN BROWN CHICKEN LOT, RAISED IN A TRADITIONAL SYSTEM

Roxana Lazăr, P.C. Boişteanu, M. Lazăr, Cristina Rîmbu

Abstract
   Infections produced by pathogenic strains of Salmonella are called salmonellosis and have an important economic and health impact. The major risk is represented by the transovarian transmission and the consumption of infected eggs which may cause severe food poisonings in humans.
   These microorganisms can be found in the intestins, but manifest tropism for the gallbladder where they may be found in large numbers and where they usually remain defining the carrier condition. In birds, most Salmonella strains don’t cause clinical signs. Even so, virulent serotypes that produce the disease exist and have specific evolution paterns. Salmonella enteritidis and Salmonella typhimurium are the most often isolated serotypes that are involved in public heath issues.
   In 2018, a salmonellosis outbreak was identified, produced by Salmonella sp. group D, in a laying hens lot, raised in a traditional system. Clinical manifestations were seen only in some individuals and consisted in low egg production, severe weight loss, sleepiness, lack of appetite, polydipsia and death. The forensic exam showed egg yolk peritonitis, increased volume of the spleen and liver, brittle liver, fibrinous exudate in the thoraco-abdominal cavity, light cattharal enteritis. Microbiological exam was done by making bacterial cultures from different organs extracted from the bird cadavers (heart, gallbladder, bone marrow, gastro-intestinal mass and the eggs in different stages of development). Identification of the etiological agent was done based on phenotypic aspects (cultural and morphological), biochemical (MIU, TSI, API-20E) and serology (Siglepath-Salmonella, Serum Anti-Salmonella D).
   After establishing a laboratory diagnostic, the laying hens lot was eliminated and after the depopulation, severe cleaning and disinfection actions were taken.

Key words: hen, microbiology, diagnostic