Isolation, identification and molecular characterization of Salmonella enterica subsp. enterica serovar Gallinarum from poultry farms of Central Kashmir, North India

Abstract

The present study was carried out to isolate and identify Salmonella enterica subsp. enterica serovar Gallinarum from local as well as commercial poultry farms of central Kashmir. Samples (Liver, lungs, spleen, heart, intestines and Bursa) from 182 birds suspected of Fowl Typhoid were collected and processed during the period of study. Grossly, liver was pale and showed bronze discolouration, lungs showed congestion and consolidation, congestion and thickening of pericardium, spleenomegaly, congestion and haemorrhages of duodenum and mild atrophy in bursa was noticed. Histopathologically, liver showed congestion with areas of necrosis and infiltration of mononuclear cells, heart showed myocardial necrosis and thickening of pericardium, lungs were congested and consolidated. Depletion of lymphocytes was observed both in spleen and Bursa, duodenum showed congestion and infiltration of mononuclear cells. Forty-two samples (42/182) were found positive for Salmonella by various cultural, biochemical techniques and twenty-one (21/42) were characterized as Salmonella enterica subsp. enterica serovar Gallinarum. Salmonella enterica subsp. enterica serovar Gallinarum was isolated from liver and identified by using bacterial culture on selective media (Xylose Ly-sine Deoxycholate (XLD), Brilliant green agar (BGA). On BGA the colonies were small, opaque and white. Whileas, on XLD agar colonies appeared as transparent and pink. The microscopic examination of colonies on Gram’s staining revealed, pink colored, short rod shaped bacteria, arranged in single or paired. Biochemical tests such as IMViC (Indole test, Methyl Red test, Voges-Proskauer and Citrate utilization) revealed that the isolates belongs to the genus Salmonella. All isolates of Salmonella species were positive to 16s rRNA gene based PCR (574 bp). All isolates of other serotypes presented negative results, suggesting these isolates to be Salmonella enterica subsp. enterica serovar Gallinarum.