Establishment of a pathogenicity index in Salmonella Enteritidis and Salmonella Typhimurium strains inoculated in one-day-old broiler chicks

Diane Alves De Lima ,R.B Morgam,Thales Quedi Furian ,R.m Pillati ,Kelly Cristina Tagliari De Brito ,Karen Apellanis Borges ,G.l Silva ,Benito Guimarães De Brito ,H L S Moraes ,Flávia Bornancini Borges Fortes ,Carlos Tadeu Pippi Salle

doi:10.1590/1678-4162-8259

Diane Alves De Lima , R.B Morgam + Show 9 more

Open Access

https://doi.org/10.1590/1678-4162-8259

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Abstract

Salmonella Enteritidis and Salmonella Typhimurium are responsible for causing huge economic loses in aviculture, as they lead young broiler chicks to develop clinical disease and thus increase mortality. Salmonella's pathogenicity is considered complex and multifactorial, demanding more studies that could elucidate the interaction between host and pathogen. The present study aims to evaluate the virulence of 130S. Enteritidis isolates and 70S. Typhimurium inoculated in one-day-old chicks through the establishment of a pathogenicity index. For each strain, 10 commercial chicks from the Cobb lineage were used. Then, 200µL of a solution containing 2x108 CFU of S. Enteritidis or S. Typhimurium were inoculated in the birds by intraperitoneal via. Mortality and presence of lesions such as aerosaculitis (A), perihepatitis (Ph), pericarditis (Pc), peritonitis (Pt), onfalitis (O) and cellulitis (C) were registered daily for seven days. From the second to the seventh day there was a proportional decrease in the punctuation of the time of death (TD) for each day that the bird had survived. The pathogenicity index was calculated using the following formula: PI = (TD x 5) + A + Ph + Pc + Pt + O + C. The obtainment of the PI of each bacterial sample was achieved by calculating the rate of the ten inoculated birds. Based on the obtained results, it was possible to attribute the pathogenicity value for each strain, which enabled us to classify them in groups of low (27/200), intermediate (95/200) and high (78/200) pathogenicity. The utilization of standards like time of death and presence of septicemic lesions made it possible to determine the pathogenicity rate for each strain. Besides that, the proposed model has presented dramatic differences between the high, intermediate and low pathogenicity groups, which makes this mechanism useful for further classification of strains isolated in poultry farms.

Highlights

Bacteria from the Salmonella genus, especially Salmonella (S.) Enteritidis and S
The occurrence of the clinical disease associated with mortality has been observed in birds that are submitted to stress conditions and young broiler chicks that have an immature immune system (Akthar et al, 2013)
Typhimurium cause infections that can lead to the development of acute septicemia, characterized by the presence of lesions such as peritonitis, perihepatitis, onfalitis, pericarditis, tiflitis, aerossaculitis and pneumonia (Desmidt et al, 1997; Dhillon, et al, 2001; Roy et al, 2001)

Summary

Introduction

Bacteria from the Salmonella genus, especially Salmonella (S.) Enteritidis and S. The occurrence of the clinical disease associated with mortality has been observed in birds that are submitted to stress conditions and young broiler chicks that have an immature immune system (Akthar et al, 2013). Studies based on experimental inoculation of these bacteria in the first week of life demonstrate that both S. Typhimurium cause infections that can lead to the development of acute septicemia, characterized by the presence of lesions such as peritonitis, perihepatitis, onfalitis, pericarditis, tiflitis, aerossaculitis and pneumonia (Desmidt et al, 1997; Dhillon, et al, 2001; Roy et al, 2001). High mortality taxes are mentioned after experimental inoculation of those serovars in one-day-old chicks (Smith and Tucker, 1980)

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