| Campylobacter is an important zoonotic pathogen that endangers human and animal health.It often causes human diarrhea enteritis,food poisoning,digestive tract infection and other diseases,of which the most common are Campylobacter jejuni and Campylobacter coli.Poultry,especially chicken,is the most important source of infection and storage of campylobacter.Pathogenic bacteria can spread through contaminated chicken products,milk,food,water and other cross-contamination and pose serious harm to human health.In order to understand the epidemic characteristics and laws of campylobacter in chicken production chain,this study investigated the contamination of campylobacter in poultry farms,slaughterhouses and markets in Guangdong,and carried out the detection and analysis of drug resistance,drug resistance genes and virulence genes.In this study,201 strains of Campylobacter were isolated from poultry farms,slaughterhouses and markets in Guangdong,with a positive rate of 14.21%.Among them,130 strains were Campylobacter jejuni,with a positive rate of 9.19%.The remaining 71 strains are campylobacter coli,with a positive rate of 5.02%,indicating that campylobacter in chicken production chain in Guangdong has a high contamination rate.In this study,the drug resistance of the above Campylobacter isolates to quinolones(ciprofloxacin CIP,nalidixic acid NA),macrolides(erythromycin E),aminoglycosides(gentamicin CN),tetracyclines(tetracycline TE),clindamycin(clindamycin DA),chloramphenicol(chloramphenicol C),Beta lactams(ampicillin AMP),sulfonamides(SMZ of sulfamethoxazole)and other 8 kinds of 9 commonly used antibacterial drugs was tested.The results showed that the resistance rate of Campylobacter isolates to quinolones and sulfonamides was very high in this region.The resistance rate of Campylobacter coli to nalidixic acid reached 100%,while it was more sensitive to Beta lactams and chloram phenicols.In addition,the isolated strain has a high multi-drug resistance rate,in whichthe proportion of Campylobacter resistant to 3 to 5 antibiotics is 38.89%,the proportion of Campylobacter resistant to 5 to 7 antibiotics is 47.22%,and the proportion of Campylobacter resistant to 7 or more antibiotics is 11.11%.In this study,15 virulence genes of the above Campylobacter isolates were tested.The results showed that the carrying rate of virulence gene htr A in Campylobacter jejuni and Campylobacter coli was above 90%.The virulence gene carrying rate of Campylobacter jejuni is significantly higher than that of Campylobacter coli,and the virulence gene carrying rate related to invasion,adhesion,colonization and encoding of cytotoxin in Campylobacter jejuni is very high.In this study,11 drug-resistant genes of 4 types of antibiotics were detected in the drug-resistant strains of the above-mentioned Campylobacter isolates.C257 T mutation occurred in the base of QRDR region of gyr A gene of all quinolone drug-resistant strains,with a mutation rate of 100%.The 23 S rRNA gene of all strains resistant to macrolipid drugs has A2075 G point mutation.In addition,the carrying rate of methylase resistance gene erm B is 52.38%.The carrying rate of tetracycline resistance gene tet(O)was 97.37%.The carrying rate of aminoglycoside resistance gene aac(6’)-Ie/aph(2")-Ia was 32.56%,and that of aminoglycoside resistance gene aph(2′′)-If was 48.84%.The experimental results of comprehensive analysis show that the Campylobacter contamination in the chicken production chain of Guangdong Province is serious,with each link contaminated;The resistance of Campylobacter isolates to common antibiotics and multidrug resistance are common;Campylobacter jejuni has a high carrying rate of virulence genes related to invasion,adhesion and secretion of cytotoxin,which has potential pathogenicity to humans;The results of drug resistance gene analysis shows that there was a close relationship between drug resistance genes and the production of resistance to Campylobacter. |
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