Bacteriological studies on bacterial pathogens isolated from broiler chickens with swollen head syndrome

Document Type : Original Article


Department of Bacteriology, Mycology and Immunology , Faculty of Veterinary Medicine, Beni-Suef University, Beni Suef 62511, Egypt.


This work was planned to investigate the bacteria isolated from broiler chickens head suffered from naked eye pathological lesions. Out of 200 examined head lesions, the result revealed that the major pathogens associated with swollen head syndrome (SHS) were Escherichia coli, Streptococcus dysgalactiae and Pseudomonas aeruginosa. Antimicrobial sensitivity pattern against 11 different antimicrobials proved that isolates were resistant to most of the tested antimicrobial agents. PCR was applied on 4 MDR E. coli, 4 S. dysgalactiae and 2 P. aeruginosa for detection of some resistance and virulence genes. The results of E. coli isolates revealed that blaTEM gene was the most prevalent in all isolates (100%) followed by tetA (A), aada1, aada2 and aacC genes. Meanwhile tetA (B) gene was found in 3 (75%), while aadB gene was not detected in any isolates. All S. dysgalactiae proved to harbour 16srRNAgene also all S. dysgalactiae were 100% positive for tuf gene followed by speF gene which found in 2 isolate (50%). The results of PCR of P. aeruginosa isolates revealed that toxA gene was the most prevalent gene found in all isolates (100%) followed by lasI. Then, phzM gene was found in one isolate (50%).


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