High Prevalence Of Coagulase-negative Staphylococci Among Poultry Houses’ Bioaerosols And Its Effects On Chicken Health

Staphylococci are a type of gram-positive bacterial,which is widely exist in poultry houses and hospital.It can cause diseases in the poultry breeding,such as poultry acute septicemia,arthritis,periostitis,which are seriously demage the economic Coagulase-negative staphylococci(CoNS)are a group of opportunistic pathogens,which are widely spread in the environment,its prevalence and characteristics in the bioaerosols of poultry houses.In relatively closed farms,bioaerosols are an important way to spear pathogens,but the prevalence and characteristics of Staphylococci in aerosols in poultry houses have not yet been determained.In this study,we collected samples among bioaerosols of nine poultry houses in central China and through continuous monitoring,proved that during the first 60 days,Staphylococci were significantly increased in bioaerosols of poultry houses,and reached the maximum on average of 2.0×10~6cfu/m~3,which account for 75.4%of total bacteria.The one hundred and two strains isolated from bioaerosols and poultry farmers’nasal swabs showed that all these bacterial were CoNS.in which covering seven species and 41.2%isolates were S.sciuri,which was the predominant species.Expect S.sciuri,there were S.equorum,S.saprophyticus,S.haemolyticus,S.xylosus,S.arlettae and S.gallinarum.Eleven antibiotics were selected for drug sensitivity testing.It showed that CoNS strains which isolated from bioaerosols were multiple drug resistance.Among them,the resistance rates of the strains to chloramphenicol,tetracycline and penicillin were higher,which were 93.14%,91.18%,69.61%.Among these CoNS,49%of the strains are resistant to oxacillin,which are called methicillin-resistant coagulase-negative staphylococcus(Methicillin-Resistant CoNS,MRCoNS).Detected by PCR,there were 36.3%of the strains carries mecA resistance genes.Further laboratory experiment through MRCoNS and methicillin-sensitive S.aureus(MSSA)by mix liquid cultured.This was the first time that we confirmed resistance gene mecA can be transmitted from MRCoNS strains to MSSA in laboratory,proving that MRCoNS were important provider of mecA for MSSA to form a‘Super Bacteria’methicillin-resistant S.aureus called MRSA.In order to explore the effects of CoNS in bioaerosols of poultry houses,10~6cfu/m~3 CoNS was selected to infect SPF chickens with aerosol nebulization.Post-mortem examination and Quantitative Real-time PCR showed that although CoNS as a opportunistic pathogen,it didn’t occur typical organ disease when chickens exposed to CoNS bioaerosols,but it can induce the lung and spleen inflammatory facors IL-1β,IL-6,IL-8 expression levels increased significantly,proving that exposure to a certain concentration of CoNS bioaerosols can induce inflammatory reactions in poultry.The results indicate that CoNS is the main bacterium in bioaerosols of poultry farming,and can induce significant up-regulation of inflammatory factors in poultry,and that can potentially affect animal performance.In addition,CoNS showed multiple drug resistance and had a high carrier rate of resistance gene mecA.It can transferred to MSSA and form MRSA.This study clarified the prevalence and drug resistance characteristics of Staphylococci in bioaerosols in poultry houses,and initially revealed its impact on the health of chickens in farms.It will provide scientific data and theoretical basis for the prevention and has important guiding signigicance for poultry breeding drugs,also provides scientific data and theoretical basis for the prevention and contro of Staphylococci in poultry farms.