Pathogenicity of bacterial isolates associated with high mortality in duckling in Behira province

D uring 2020–2022, a survey of 25 farms of ducklings of various breeds (Pekini and Muscovy), that ranged from one day up to a month of age suffering from various symptoms and mortality rates varied from 10 to 35 % revealed isolation of Klebsiella pneumonae 36 % whereas the prevalence of E coli, Staph aureus and Salmonella Typhimurium were 32%, 28% and 16% respectively. Following PCR confirmation of Klebsiella pneumonae, the presence of the its virulence genes were sur-veyed and results showed that uge (44%) and rmpA (22%), as well as an antimicrobial susceptibility profile , which revealed 100% resistant to Ampicillin, Amoxicillin and Penicillin G followed by77 % toward tetracycline, 22% toward streptomycin . Contrarily, they were extremely sensitive to ciprofloxacin and enrofloxacin, as well as 77% to cefotaxime and 66% to gentamycin. The surveillance of class 1 integron ( intl1) and genes of antimicrobial resistance demonstrated that (66%) of isolates harbor Int1,whereas only 33% of the isolates involved blaSHV, they all had the tetA and blaTEM genes. Salmonella and E. coli isolates were serotyped, and it was discovered that the E. coli isolates belonged to six different O-serogroups, including O55:H7, O148:K25, O86: K61, O114:H21, O26:H11 and O127:H6