ABSTRACT
We investigated the contamination,antimicrobial resistance and the virulence genes carriage of Salmonella spp. in duck slaughter chain.Suspected strains were isolated from slaughterhouse samples according to GB 4789.4-2010 and identi-fied by duplex PCR,and then the positive strains were used for serotype analysis.Subsequently,positive strains were tested against 10 different antimicrobial agents using Kirby-Bauer disk diffusion method,the results were determined on the basis of CLSI standard.Finally,9 virulence genes were detected among positive strains by PCR.The results showed that 9 9 Salmonella isolates were recovered from 343 samples and total isolation rate was 28.86%.The prevalence of Salmonella before slaughte-ring,at depilation stage,at evisceration stage,in duck meat and after slaughtering was 45.71%,22.68%,24.72%, 38.33% and 25.81%,respectively.Seven serotypes were de-tected and most of them were S.Indiana,S.Newlands,S. Anatum.The Salmonella isolates were most frequently re-sistant to nalidixic acid(91.92%),the resistance rates of tet-racycline (43.43%),ampicillin (42.42%),trimethoprim-sulfamethoxazole (34.34%),ciprofloxacin (29.29%),ceftri-axone (27.27%),gentamycin (24.24%),and kanamycin (22.22%)were at a medium level.The resistance rates of amoxicillin-clavulanic acid (9.09%)and minocycline (6.06%)were relatively low.The multi-drug resistance rate of Salmonella isolates,which was 47.47%,showed a high especially in S.Indi-ana,S.Typhi and S.Typhimurium.It was notable that the harboring rates of virulence gene spvR(94.95%),avrA (93.94%),ssaQ(90.91%),mgtC(87.88%),sopB(83.84%),bcfC(80.81%),siiD(77.78%)among Salmonella isolates were at high level,in contrast to the lower carriage rates of spvB(29.29%),spvC (11.11%).In summary,the results indica-ted that the duck slaughter chain was easily contaminated by Salmonella spp.with different serotypes,different antibiotic re-sistant patterns and high virulence genes harboring rate.Relevant slaughterhouse and departments should strengthen supervi-sion in sanitation and manage the use of antimicrobial agents,to guarantee food safety and public health．
ABSTRACT
The text has isolated 267 strains LAB from the traditional fermentative food in Sichuan. Using agar plate proliferation experiment and double-layer agar plate proliferation experiment (eliminating the effects of organic acid and H_2O_2, decreased after treatment with trypsin and papain) to screen a LAB of Bacteriocins P158 which has antibacterial action to Escherichia coli, Staphylococcus aureus, Micrococcus luteus, Pseudomonas aeruginosa, Bacillus subtilis. P158 was isolated from fermented glutinous rice. Through detection of its appearance, physiological and biochemical characteristics and 16S rDNA gene sequence homology analysis, it was identified as Lactobacillus plantarum.