Bacteria associated with early mortalities in broiler farms with regard to antibiotics and disinfectants resistance genes

Abstract

In this study, we shed the light on the main three bacterial pathogens involved in the early mortalities in broiler farms in Egypt. Five hundred organ samples (liver, yolk sac, cecum, spleen, and heart) were collected aseptically from freshly dead affected chicks. The samples were cultured on different media for isolation of causative agents by conventional and serological methods. The microbiological examination revealed isolation of Salmonella, E. coli, and P. aeruginosa in percentages of 23%, 25%, and 8% respectively. The serotyping of Salmonella isolates revealed the existence of nine serovars with different percentages. S. Enteritidis possessed the highest percentage with six isolates out of twenty-three with a percentage of 26%. S. Kentucky, and S. Typhimurium came in the second category with a percentage of 4%, and 3% respectively. S. Tamale, S. Inganda, and S. Takoradi have the same isolation percentage of 8.69%. S. Molade, S. Labadi, and S. Papuana have the same isolation percentage of 4.34%. The serotyping of E. coli isolates proved the existence of 12 serotypes. O78 possessed the highest percentage of isolation followed by O2, O158, and O91 with the same percentage of 12% for each serotype. O128, and O1 isolated with the same percentage of 8%. O145, O144, O125, O119, O26, and O146 have the lowest percentage of isolation with a percentage of 4% for each one. Single and mixed infections were observed as 41, and 7%, respectively. An antibiotic sensitivity test was carried out according to the standard method to detect the sensitivity range of the different isolates against different eight antibiotics belonging to 6 families of antibiotics. 86.9% of Salmonella serovars, 48% of E. coli serotypes, and 87.5% of P. aeruginosa isolates were resistant to colistin sulphate, norfloxacin, and florfenicol respectively.