Pathogenicity of Environmental Origin Salmonellas in Specific Pathogen-Free Chicks

Abstract

Two hundred sixty 1-d-old specific pathogen-free (SPF), Single Comb White Leghorn chicks were used in this study to determine pathology caused by Salmonella enteritidis (SE) isolated from a poultry environment. The chicks were subdivided into 10 equal groups of 26 chicks each. Eight groups of chicks were inoculated individually with 0.5 mL of brain heart infusion broth culture containing 1 x 10(6) cfu of SE phage type (PT) -8 (1, 2, 3), SE PT5 A (1, 2), or SE PT4 (Ch-env-CA, chicken-CA, and human) by crop gavage. One group of 26 chicks were inoculated with 1 x 10(6) cfu of Salmonella pullorum per bird by crop gavage. Another group of 26 chicks were kept as an uninoculated control group. All the chicks were observed daily for clinical signs and mortality. Salmonella was reisolated from different organs at 7, 14, 21, and 28 postinoculation (DPI). All of the chicks were weighed individually at each interval. Two chicks at random from each group were euthanised and necropsied at each DPI for gross pathology. Selected tissues were examined for histopathological changes at 7 and 14 DPI. Dead chicks were examined for gross and histopathological lesions. Mortality rates were 30.7, 15.3, and 7.6% in the groups inoculated with S. pullorum, SE PT5A, and SE PT4 (chicken-CA), respectively. No mortality or clinical sign were observed in other treatment groups or in uninoculated control groups. Cecal pouches were found to be the ideal organ for reisolation of Salmlonella at acute or chronic infection compared with other organs. Mean body weights were reduced to 1.8 to 12.6% in inoculated groups compared with the uninoculated control group. The consistent gross and hispathological lesions were of peritonitis, perihepatitis, yolk sac infection, and enteritis. Subclinical Salmlonella infection identified in this study resulted in reduced body weights of inoculated birds compared with uninoculated controls.

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

“…Between the evaluated lesions, aerossaculitis, peritonitis and onfalitis were the most common occurrences in both studied serotypes. These findings are similar to the ones described by many researches after experimental infection with S. Enteritidis (Desmidt et al, 1997;Dhillon et al, 1999;Alisantosa et al, 2000;Dhillon et al, 2001;Akthar et al, 2011;Akthar et al, 2013) and S. Typhimurium in Specific Pathogens Free (SPF) birds between one and twenty-eight days.…”

“…Similarly Dhillon et al (2001) describes that pericarditis was not common in birds that were found dead after the inoculation with different fagotypes of S. Enteritidis. Nevertheless, this finding differs from the ones observed by Roy and contributors (2001) who describe the presence of fibrinous exudate in the pericardium as one of the main macroscopic lesions observed in SPF chicks after oral inoculation of 10 7 CFU of S. Typhimurium.…”

“…However, 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. Enteritidis and 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). Similarly, high mortality taxes are mentioned after experimental inoculation of those serovars in one-day-old chicks (Smith and Tucker, 1980).…”

Initial identification and sensitivity to antimicrobial agents of Salmonella sp.isolated from poultry products in the state of Ceara, Brazil

“…Hong'ombe et al (1999) identified S. enteritidis in broiler carcasses ready for market in several different situations. Many authors identified poultry products as sources of infection of Salmonella that causes enteritis in humans (Dhillon et al, 2001). Approximately 10% of salmonellosis cases are caused by poultry meat, and in the United States, there are between 15 and 20 cases of salmonellosis for each 100,000 people (Bryan & Doyle, 1995).…”

Characterization of the invasiveness of monophasic and aphasicSalmonellaTyphimurium strains in 1-day-old and point-of-lay chickens

“…Also, the challenge dose (1 × 10 5 CFU) administered to the chicks was selected to minimize the risk of any clinical signs and thus reduce the chance of any adverse consequences for the birds. A higher dose might have led to a more extensive tissue invasion, but could have caused clinical disease (Barrow et al, 1987;Dhillon et al, 2001). Strain F (4,5, and strain G (SE) colonized more effectively in the chicks (the number of positive tissues recovered was higher and there were positive samples after direct plating, suggesting that a higher number of salmonellas was present in the tissues).…”