RESUMO
This study was aimed to understand the current status of the antimicrobial resistance and molecular distribution of Campylobacter in various poultry in Jiaodong area,to provide a basis for effective prevention and control of the Campy-lobacter risk to poultry products and human health.Campylobacter was isolated and identified from 565 cloacal samples collect-ed in the Jiaodong area from August to October 2021 through conventional bacterial isolation and culture,mass spectrometry,microbroth dilution and multilocus sequence typing(MLST).The drug resistance and molecular typing of 131 representative strains(67 Campylobacter jejuni and 64 Campylobacter coli)were studied separately.Antimicrobial resistance analysis indica-ted that 131 isolates were highly resistant to ciprofloxacin,nalixic acid and tetracycline,with resistance rates of 96.21％,96.21％and 95.45％,respectively.Except for 2 strains,62 strains of C.coli were completely resistant to these three drugs(100％).A total of 65 strains of 131 strains were multidrug re-sistant,and the overall multidrug resistance rate was 49.62％,among which 11 strains(16.42％)of C.jejuni were resistance to 3-5 antibiotics,and 54 strains(84.38％)of C.coli were re-sistance to 3-6 antibiotics.Among the isolates from different poultry sources,waterfowl isolates were the most resistant,fol-lowed by broiler isolates.The MLST typing results revealed 72 alleles and 35 sequence types obtained from 67 strains of C.je-juni,and the distribution was relatively dispersed,without a dominant ST type and homologous complex.A total of 27 alleles and 19 sequence types were obtained from 64 strains of C.coli.Moreover,59.38％(38/64)strains were homologous complex CC-828,in which the ST-1586 sequence type was most frequent,followed by ST-825.ST-1586,ST-9944 and ST-3735 were the main sources of C.coli in broilers,and ST-825 and ST-1586 were the main sources of C.coli in waterfowl.Differences in C.jejuni and C.coli carriage were observed among poultry in the Jiaodong area.Carriage of the two bacteria was more common in laying hens than in broilers and waterfowl.C.jejuni from poultry in the Jiaodong area was highly resistant to ciprofloxacin,nalixic acid and tetracycline,but had good sensitivity to other drugs.C.coli was highly resistant to a variety of antibiotics,and multiple drug resistance was common.St-type dispersal of C.jejuni showed high genetic diversity.C.coli was cloned and transmitted mainly by ST-1586 in broiler chickens and waterfowl.Poultry carry C.jejuni,which can cause serious diseases in humans.Therefore,dynamic monitoring of Campylobacter from poultry should be strengthened.
RESUMO
We established a multiplex direct PCR for rapid detection of E.coli,Salmonella,Staphylococcus aureus,Listeria and Yersinia enterocolitica bacteria.Multiplex direct PCR primers were designed according to gene sequences of phoA (E.coli),inv A (Salmonella),nuc (S.aureus),hl y (Listeria),and ail (Y.enterocolitica).After the multiplex direct PCR were established,the specificity and sensitivity of primers were detected.Then,multiplex direct PCR was applied to examine 60 swine product samples,the detection specificity,accuracy and positive predictive value were calculated compared with the gold standard culture method.Results showed that multiplex direct PCR primers could be used for specific detection of E.coli,Salmonella,S.aureus,Listeria and Y.enterocolitica,with the minimal detectable limit of 10,1,100,1 and 1 CFU,respectively.For the examination of 60 swine product samples using multiplex direct PCR,15 were positive for E.coli,6 positive for Salmonella,21 positive for S.aureus,20 positive for Listeria,and 35 positive for Y.enterocolitica,with all positive detection rates higher than that of culture.The total detection sensitivity was 100％,accuracy was 94％,and positive predictive value was 81.44％.Multiplex direct PCR could be used for specific and sensitive detection of common food-borne pathogens,and the testing time was shorten to be 3 hours because of saving time for template extraction.Multiplex direct PCR might serve the detection of food-borne pathogens in food safety risk monitoring much better.