Transcriptional responses of cytokines, immunoglobulin A, and nitric oxide genes in 1-day-old chicks post infection: An experimental study.

BACKGROUND

has become one of the hazards prevalent foodborne pathogens causing different diseases in chickens. However, (ST), a nonhost-specific serovar, is a major avian agent that causes severe disturbance in young chicken wellness.

AIM

The occurrence of in chickens and their antimicrobial resistance were explored in this study. In addition, the immune response of 1-day-old broiler chicks, against multidrug resistant (MDR) ST infection, was also assessed at 4 and 24 hours post infection (pi) in the cecum and spleen, representing their mucosal and systemic immune responses, respectively.

METHODS

A total of 375 samples from 130 diseased and apparently healthy broiler and layer chickens were randomly collected for isolation, identification, and resistance profile evaluation, from farms and different clinical laboratories. The immune response of 1-day-old broiler chicks, Ross 308, against - ST infection was ascertained through the evaluation of heterophile phagocytosis and s expression of cytokines, immunoglobulin A and other immune-regulating genes in the cecum and spleen. Twenty-four, 1-day-old nonvaccinated broiler chicks were used and divided into two groups. The chicks in the infected group were orally inoculated with 0.5 ml of 2 × 10 colony forming units (CFU)/ml of MDR ST suspension while those in the control group were taken nutrient broth.

RESULTS

Seven out of 130 (5.38%) examined chickens were positive for . All isolates (100%) were resistant to amoxicillin-clavulanic acid (AMC), cefazolin (CZ), cefoxitin (FOX), ciprofloxacin (CIP), nalidixic acid (NA), tetracycline (TE), fosfomycin (FOS), and colistin (CT) with multiple antimicrobial resistances (MARs) index range of 0.72-0.83, where none of them was resistant to meropenem (MEM). The results of immune response revealed that chicks infected with ST showed significantly different phagocytosis percentages and index values compared to controls. According to the real-time quantitative polymerase chain reaction (RT-qPCR) results, the transcription of and for chicks infected by ST showed a significantly increased trend ( < 0.01) with increasing chicken age and was higher in the cecum than spleen compared to controls ( < 0.05) during 24 hours after infection.

CONCLUSION

The findings indicated a strong mucosal immune response in the chicks after the ST challenge, which reflects humoral and cellular responses. Our insight recommended the occurrence of a natural immune response stimulator at 1 day age to face the infection, and this can prevent the resistance transfer, with efficient control measures.