Background Salmonella is one of major causes of foodborne outbreaks globally.
This study was conducted to estimate the prevalence, typing and antibiotic
susceptibilities of Salmonella enterica serovars isolated from 41 broiler
chicken farms located in Kafr El-Sheikh Province in Northern Egypt during
2014–2015. The clinical signs and mortalities were observed. Results In total
615 clinical samples were collected from broiler flocks from different organs
(liver, intestinal content and gall bladder). Salmonella infection was
identified in 17 (41%) broiler chicken flocks and 67 Salmonella isolates were
collected. Recovered isolates were serotyped as 58 (86.6%) S. enterica serovar
Typhimurium, 6 (9%) S. enterica serovar Enteritidis and 3 (4.5%) were non-
typable. The significant high mortality rate was observed only in 1-week-old
chicks. sopE gene was detected in 92.5% of the isolates which indicating their
ability to infect humans. All S. enterica serovar Enteritidis isolates were
susceptible to all tested antimicrobials. The phenotypically resistant S.
enterica serovar Typhimurium isolates against ampicillin, tetracycline,
sulphamethoxazole and chloramphenicol were harbouring BlaTEM, (tetA and tetC),
(sul1 and sul3) and (cat1 and floR), respectively. The sensitivity rate of S.
enterica serovar Typhimurium to gentamycin, trimethoprim/sulphamethoxazole and
streptomycin were 100, 94.8, 89.7%, respectively. The silent streptomycin
antimicrobial cassettes were detected in all Salmonella serovars. A class one
integron (dfrA12, orfF and aadA2) was identified in three of S. enterica
serovar Typhimurium strains. Conclusions To the best of our knowledge, this
study considered first report discussing the prevalence, genotyping,
antibiotic susceptibility and public health significance of S. enterica
serovars in broilers farms of different ages in Delta Egypt. Further studies
are mandatory to verify the location of some resistance genes that are within
or associated with the class one integron