Dissertation
Dissertation > Medicine, health > Preventive Medicine,Health > Nutrition, hygiene,food hygiene > Food hygiene and food inspection > Food hygiene and inspection

Study on Types and Active Surveillance of Foodborne Salmonella.spp in Shandong Province

Author ShaoKun
Tutor BiZhenQiang;WangXianJun
School Shandong University
Course Epidemiology and Health Statistics
Keywords foodborne Salmonella.Spp serotype resistance PFGE fingerprinet
CLC R155.5
Type Master's thesis
Year 2011
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Objective:According to active surveillance on foodborne Salmonella.Spp from 2003 to 2010 in Shandong Province, to understand the contamination level an Characteristics of Salmonella.Spp and determine the serotype distribution of isolated strains.To understand antibiotic sensitivities of Salmonella.Spp and compare of resistance phenotype differences and set up antibiotic sensitivities spectrum database. Applying of PFGE technology,to compare of different sources of Salmonella. Spp homology and to establish PFGE fingerprint database of Salmonella.Spp and to analysis the molecular type of foodborne Salmonella.Spp in Shandong Province.Method:According to the criterion of national food sanitation examination method(GB4789-2003)and national food borne pathogens examination method in China, eight kinds of foods were examined in eight surveillance points of Shandong Province form 2003 to 2010. According to the CLSI standard recommended by the Clinical Laboratory Standards Institute about antibiotics senstivity test of Salmonella.Spp the Broth microdilution method was used to determine the susceptibility of 16 kinds of antibiotics.Quality control is regularly performde by running specific control E.coli ATCC25922.The Salmonella.Spp genome which was cleavaged by restriction enzyme Xba I were carried out by pulsed -field gel electrophoresis.The PFGE fingerprint was analysed by the software BioNumerics 6.1. Result:A total of 3335 samples of eight kinds of foods including raw milk,raw pork,mutton,poultry meat,cooked meat vegetables,aquatic products were examined from 2003 to 2010,and 96 strains of Salmonella.Spp were isolated and the total positive rate in all samples was 2.88%,and that of poultry meat and raw pork was the highest,which reached 7.44% and 7.37%.Raw milk was not detected Salmonella.Spp. The highest positive rate of Salmonella.Spp for each year was in 2010 (4.48%), and the lowest was in 2006(1.47%),followed by other years was 2009(4.38%),2008(3.79%),2007(2.46%),2004(2.07%),2003(1.69%),2005(1.61%). The highest positive rate of Salmonella.Spp in all surveillance points was Linyi point(6.67%),and the lowest was Liaocheng(0.74%).The 94 Salmonella Spp strains which had been identified serotypes from 96 strains were belonged 4 group,6 subgroup,15 serotypes. S.Enteritidis and S.Derby were the most conmmon serotypes which were detected 51 strains(53.13%) and 18 strains(18.75%).The 120 Salmonella strains had been identified serotypes from 126 strain It was the firse time that S.Chwarzengrund,S.Wien,S.Blegdam,S.Muenster and S.Ughelli were detectde in Shan Dong Province.126 Salmonella strains were resistant to 14 antibiotic in different degree.,and the most sensitive to Cefepime (5.37%) following by Amikacin(9.52%) and Ciprofloxacin(10.32%).The high rate of antibiotic resistance was Nilidixic acid(61.90%).the followingby Tetracycline (33.33%), Ampicillin (31.75%),Sulfadiazine(26.19%). The main antibiotic resistance was single antibiotic resistance(Nilidixic acid) and sensitive resistance,the respective occupancy was 35.71%and 26.19%.The percentage of over ten-resistance was 10.52%.The multi-drug resistance of S.Enteritidis showed a rise trend during three time.The cluster analysis of PFGE fingerprint showed that Salmonella Spp were classified as 31 gene types and 72 PFGE fingerprint types.57 strain of S.Enteritidis were classified as 12 gene types and 40 PFGE fingerprint types,and the similarity coefficient was between 41.24% and 100%. XB17. type of S.Enteritidis accounted for 39 (69.42%),XB20 and XB22 type 4 strain(7.02%), XB23 type 3 strain(5.26%),XB21 type 2 strains (3.51%),other types were 1 strain. 7 strains of S.Enteritidis which detected from the incidents of food poisoning all belong to XB17 type.and 6 strain had the same PFGE fingerprints with the strain which detected from food,and similarity coefficient of the other one was also above 90%.Conclusion:Active surveillance results showed that the contamination of Salmonella.Spp was relatively serious,and had a rise trend.The advantage serotypes in Shandong Province were S.Enteritidis and S.Deby.The main antibiotic strains were single antibiotic resistance and sensitive resistance, but the antibiotic such as Nilidixic acid,Tetracyline Penicillin which used antibiotic agents in animal as a food source for human had. strong resistance.Multi-durg resistance particularly over ten-resistance began to increase every year in Shandong Province.According to establishing the PFGE fingerprint database of Salmonella.Spp there will provide a theoretical basis for association of foodborne infectious disease,investigation of outbreak and rapid identification of epidemic sources.v

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