ABSTRACT
Objective@#To investigate the contamination status of Salmonella, Vibrio parahaemolyticus and Staphylococcus aureus and bacterial resistance in retail meat products in Taiyuan, Shanxi Province.@*Methods@#In the epidemic season of diarrhea in 2017, poultry and meat product specimens were randomly collected from the farmer′s markets and supermarkets of 10 districts and counties of Taiyuan. Salmonella, Vibrio parahaemolyticus and Staphylococcus aureus were isolated form these specimens. Serotypes of Salmonella strains were analyzed. ELSIA was used to detect Staphylococcus aureus enterotoxin (A-E). Vibrio parahaemolyticus isolates were tested for the virulence genes encoding direct hemolysin (tdh) and indirect hemolysin (trh). Antibiotic resistance of the three food-borne pathogens were analyzed using microdilution methods.@*Results@#A total of 38 food-borne pathogens were isolated from 123 poultry and livestock meat product specimens with a positive rate of 30.9%, of which mainly were Salmonella (26 strains, 21.1%), followed by Vibrio parahaemolyticus (8 strains, 6.5%) and Staphylococcus aureus (4 strains, 3.3%). The 26 strains of Salmonella belonged to 10 serotypes. The Salmonella strains isolated from pork specimens had diverse serotypes. Salmonella serovar Derby, Salmonella serovar Gold-coast and Salmonella serovar Liverpool were isolated from raw and cooked pork food for the first time in Taiyuan. All Salmonella strains isolated form chicken products were Salmonella enteritis. The enterotoxin types of the four Staphylococcus aureus strains were three E-type and one complex type (A/E). All Vibrio parahaemolyticus isolates were negative for tdh or trh gene. Ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracyclines (ACSSuT) resistance was prevalent in multi-drug resistant (MDR) Salmonella strains, but there was high sensitivity to fluoroquinolones and cephalosporins. MDR Staphylococcus aureus accounted for 75%. No third-generation cephalosporin- or fluoroquinolone-resistant or MDR Vibrio parahaemolyticus strains were isolated.@*Conclusions@#There were food-borne multi-pathogenic bacteria contamination in retail raw and cooked meat products in Taiyuan. Salmonella strains had diverse serotypes and high MDR rate. It was suggested that the regulatory authorities should strengthen the management of antibiotic use in aquaculture and specialized laboratory-based monitoring of meat supply chain.
ABSTRACT
Objective To investigate the contamination status of Salmonella, Vibrio parahaemo-lyticus and Staphylococcus aureus and bacterial resistance in retail meat products in Taiyuan, Shanxi Prov-ince. Methods In the epidemic season of diarrhea in 2017, poultry and meat product specimens were ran-domly collected from the farmer's markets and supermarkets of 10 districts and counties of Taiyuan. Salmo-nella, Vibrio parahaemolyticus and Staphylococcus aureus were isolated form these specimens. Serotypes of Salmonella strains were analyzed. ELSIA was used to detect Staphylococcus aureus enterotoxin (A-E). Vibrio parahaemolyticus isolates were tested for the virulence genes encoding direct hemolysin (tdh) and indirect hemolysin (trh). Antibiotic resistance of the three food-borne pathogens were analyzed using microdilution methods. Results A total of 38 food-borne pathogens were isolated from 123 poultry and livestock meat product specimens with a positive rate of 30. 9％ , of which mainly were Salmonella (26 strains, 21. 1％ ), followed by Vibrio parahaemolyticus (8 strains, 6. 5％ ) and Staphylococcus aureus (4 strains, 3. 3％ ). The 26 strains of Salmonella belonged to 10 serotypes. The Salmonella strains isolated from pork specimens had diverse serotypes. Salmonella serovar Derby, Salmonella serovar Gold-coast and Salmonella serovar Liver-pool were isolated from raw and cooked pork food for the first time in Taiyuan. All Salmonella strains isolated form chicken products were Salmonella enteritis. The enterotoxin types of the four Staphylococcus aureus strains were three E-type and one complex type (A/ E). All Vibrio parahaemolyticus isolates were negative for tdh or trh gene. Ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracyclines (ACSSuT) resistance was prevalent in multi-drug resistant (MDR) Salmonella strains, but there was high sensitivity to fluoroquinolones and cephalosporins. MDR Staphylococcus aureus accounted for 75％ . No third-generation cephalosporin- or fluoroquinolone-resistant or MDR Vibrio parahaemolyticus strains were isolated. Conclu-sions There were food-borne multi-pathogenic bacteria contamination in retail raw and cooked meat prod-ucts in Taiyuan. Salmonella strains had diverse serotypes and high MDR rate. It was suggested that the regu-latory authorities should strengthen the management of antibiotic use in aquaculture and specialized laborato-ry-based monitoring of meat supply chain.
ABSTRACT
The five kinds of food-borne pathogenic bacteria including Salmonella sp.、Shigella sp.、Pseudomonas aeruginosa、Eterohaemorrhagic O157 and Vibrio rahaemolyticus that couldn't be detected in drinking water. The five pairs of primers were designed and composed according to the toxin genes, high-conservative genes and specific genes of these pathogens. The specificity of individual primer pairs in PCR was evaluated on DNA templates of more than thirty different bacterial isolates from ten species. Through optimizing the system and condition of multioplex-PCR, the detection sensitivity was improved dramatically. Multiplex-PCR analysis was primary performed on several water samples. The method established shortened the detection time and provided a cost-effective way in maximum. The experiment showed the multiplex-PCR using the five pairs of primers produced specific amplicons of expected sizes, the detection limits for the bacterial targets were estimated at 10~(1)~10~(2)cfu for one essay. It only took five to six hours to detect a sample, got the single, steady and clear result when the method was applied primarily in the analysis of water samples. The informative supplement to those areas which were environmental inspection, water detection, food sanitation supervision , commodity inspection and detection, etc.