AVALIAÇÃO IN VITRO DO ANTAGONISTMO DE Lactobacillus spp. ISOLADOS DE AVES DE POSTURA COMERCIAL, FRENTE A QUATRO SOROVARES DE Salmonella spp.

Abstract

Salmonella spp. is a major cause of food poisoning in humans worldwide, and the consumption of poultry products contaminated the main way of infection. Once introduced into poultry production systems, these microorganisms spread quickly, favoring the contamination of meat and eggs, in addition to disturb the performance indexes. Salmonella spp represents a serious problem for public and animal health; as a result, many efforts have been adressed to its control in poultry farming. The use of competitive exclusion products (CE) would be the most effective tools available to control these bacteria. CE products assist in the prevention of entry of a pathogen into a pre-colonized intestinal tract. In this case, a mixture of bacterial strains, especially belonging to the genera Lactobacillus, Lactococcus, Bifidobacterium, isolated from adult birds is orally administered to chicks on the first day of life, accelerating the maturation process of the gut microbiota. This study aimed to isolate a strain of Lactobacillus spp. of cecal feces of adult laying hens and to assess its potential to make a commercial CE product. For this, we evaluated the antimicrobial resistance profile and its ability to inhibit, through the "spot on the lawn" method, the multiplication of four serovars of Salmonella (Salmonella Enteritidis, S. Typhimurium, S. Senftenberg and S. Heidelberg). The isolated Lactobacillus spp. caused more than 2.6 cm of inhibition zone in the multiplication of all serovars. Inhibition was significantly higher for S. enteritidis (3.8 cm). The isolate was resistant to five antibiotics of three different classes (cephalothin, ciprofloxacin, norfloxacin, enrofloxacin and erythromycin). Therefore, although the strain of Lactobacillus spp. isolated in this study have shown ability to inhibit the multiplication of Salmonella serovars and it showed multiresistance. Therefore, it would not be recommended to be part of a commercial CE product.