Staphylococcus aureus and Staphylococcal enterotoxin detection in raw milk and cheese origin coagulase positive isolates (original) (raw)
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Detection of enterotoxigenic Staphylococcus aureus isolates in raw milk cheese
Letters in Applied Microbiology, 2007
Aim: To develop an easy, rapid and efficient DNA extraction procedure for Staphylococcus aureus detection with a low number of steps and removing completely the PCR inhibitors, applicable to raw milk cheese samples, and to compare phenotypical and genotypical method to detect Staph. aureus isolates and staphylococcal enterotoxins (SEs) production. Methods and Results: A total of 33 bovine and caprine raw milk cheese samples were analysed by means of both classic microbiological and molecular techniques. All samples were positive for Staph. aureus contamination. The DNA extraction protocol optimized was found to achieve a detection limit of 100 CFU g )1 for Staph. aureus. None of the samples tested with immunological assays contained SEs but in 14 of 33 samples a mixture of se positive (sea, sec, sed, seg, sel, sej) isolates were identified. Conclusions: Staphylococcus aureus is a food-borne pathogen mainly detected in finished dairy products. The rapid and efficient detection of Staph. aureus isolates from dairy products is essential for consumer safety. The direct detection of pathogens from food is possible with careful attention to sample preparation and nucleic acid amplification optimization. Significance and Impact of the Study: This study shows that raw milk cheese samples can be tested for Staph. aureus contamination with a rapid, simple and reproducible procedure.
Journal of Ancient Diseases & Preventive Remedies, 2017
Aim: Staphylococcus aureus was categorized as a contagious pathogen incriminated in subclinical mastitis as well as in dairy products. From public health view, this organism causing food poisoning outbreaks via contamination of food products with its toxins. These studies highlight the prevalence of staphylococcus aureus among subclinical mastitic cases as well as cheese samples and the dominant enterotoxigenic genes. Methodology: Examination of 100 samples (50 from subclinical mastitis, and 50 kareish cheese) from Sadat city, Menoufia province. Results and interpretation: Bacteriological culturing on selective and specific medium revealed that 26.7% and 30% in subclinical mastitis and kareish cheese respectively were due to S. aureus. Furthermore, multiplex PCR proved to be efficient technique for detection of different enterotoxins genes. The sea, seb and see genes were the most prevalent genes among the tested S. aureus isolates. Although, no detection of sec and sed genes were observed. Conclusion: It can be concluded that molecular characterization of S. aureus and its enterotoxins genes will be beneficial in designing control and preventive measures of S. aureus infection in human and animals.
Anais da Academia Brasileira de Ciências
In this work, we investigated the phenotypic profile of Staphylococcus spp. isolates recovered from raw milk and artisanal cheese, and their enterotoxigenic potential through the detection of classical enterotoxin genes (sea, seb, sec, sed and see). A total of 104 isolates (58 coagulase-positive Staphylococcus-CoPS; and 46 coagulasenegative Staphylococcus-CoNS) were used, of which 33 were retrieved from raw milk and 71 from artisanal cheese produced in the Serrana region of Santa Catarina. Identification of CoPS was conducted via biochemical tests. Detection of the genes sea, seb, sec, sed, and see was carried out by multiplex PCR technique. Among the 58 CoPS analyzed, 64% were identified as S. aureus, 22% as S. scheiferi coagulans, 12% as S. hyicus and as 2% S. intermedius. In the present study was noted that 40% of CoPS isolates retrieved from milk harbored seb gene, while only one from artisanal cheese was positive for gene sea. In this study all CoNS samples investigated were negative for enterotoxins genes. The enterotoxigenic potential of CoPS, is an issue of great importance for public health. For that reason, it is necessary that cheese factories strictly follow the safety processes involved in manufacturing.
Macedonian Veterinary Review
The primary objective of our study was to detect the occurrence of enterotoxigenic Staphylococcus aureus in diverse types of cheese (cow's milk cheese and mixed milk cheese) samples from R.N. Macedonia. Cheese samples were analyzed for enumeration and isolation of the S. aureus strains according to ISO 6888-1. We detected the toxigenic potential of the strains by the use of the Enzyme Link Fluorescent Assay VIDAS system, and we confirmed the presence of the SEs (sea, seb, sec, sed, see) genes by multiplex PCR. The results showed that out of 270 samples of cheese, coagulase-positive staphylococci (CPS) were detected in 27 (10%), and coagulase-negative staphylococci in five samples (1.8%). Biochemically, all 27 CPS samples were confirmed to be Staphylococcus aureus. With VIDAS SET2 test we confirmed that 11 isolates are producers of one of the toxins limited by the test. With the conventional PCR we confirmed genes in only 7 isolates. Most common detected gene was seb n=3 (42.8%),...
Antibiotics
The main objectives of the present study were to determine the occurrence of coagulase positive staphylococci (CPS) and to assess the presence and antimicrobial susceptibility profile of Staphylococcus aureus isolates in different raw milk origin (cow and sheep) traditional cheeses marketed in Banat region, Romania. Additionally, the presence of mecA gene in S. aureus isolates and the staphylococcal enterotoxins (SEs) in cheese samples were evaluated. A total of 81.6% (138/169) of the screened samples were positive for CPS. Furthermore, 35.5% (49/138) of the investigated CPS positive cheese samples were contaminated with S. aureus, with an isolation frequency of 46.6% (14/30) in caș, 33.3% (32/96) in telemea, 25% (2/8) in burduf, and 25% (1/4) in urdă assortments, respectively. From the total number of S. aureus isolates, 6.1% (3/49) harbored the mecA gene. Detectable levels of SEs were identified in 4.3% (4/94) of cheese samples with a CPS contamination level higher than 105 log CF...
COAGULASE POSITIVE ENTEROTOXIGENIC STAPHYLOCOCCUS AUREUS COUNT IN PARAGUAY SEMI-HARD CHEESE
Sift Desk Journals, 2016
Background: One of the foodborne diseases of high incidence in the Latin American region is Staphylococcal intoxication, due to food contaminated with enterotoxins produced mainly by Staphylococcus aureus. The aim of this study was to enumerate, isolate and characterize S. aureus enterotoxigenic in Paraguay cheeses obtained at markets in Paraguayan cities. Methods: Three hundred eighty-two cheese samples were analyzed according to ISO 6888-1. Biochemical test, enterotoxin production ability and genotype characterization by PCR multiplex were performed to isolate. Results: Eight point thirty-seven percent of samples contained typical colonies of coagulase-positive S. aureus. Fourteen strains had the gene encoding enterotoxin A. Conclusion: The presence of coagulase-positive S. aureus in the cheese samples revealed a latent state of staphylococcal food poisoning outbreaks in Paraguay. Type A enterotoxigenic S. aureus is the most frequent isolation in this type of products, and multiplex PCR method is an effective and fast identification technique.
Enterotoxin A Gene Barrier Staphylococcus aureus Within Traditionally Dairy Products of Tehran
International Journal of Enteric Pathogens, 2014
Background: Staphylococcus aureusis a serious agent that often colonize dairy products all over the world. Staphylococcal enterotoxins are the essential causes of food poisoningin human societies. Enterotoxin type A is an importantstaphylococcal exotoxin. Objectives: The aim of present study was to detect the enterotoxin producing Staphylococcus.aureus within different dairy products collected from Tehran, Iran. Materials and Methods: Two hundreds twenty dairy products samples were collected from local dealers across the city. The samples were first screened for S. aureus contaminations. All isolated strains of S. aureus were then investigated for enterotoxin a gene, usind spesific primer sets. Results: Staphylococcus aureus was isolated from 43% of dairy samples: 22% from milk and 18% from cheese samples. The SEA genes were detected in 10 isolates (22%) originated from raw milk and in two isolates (25%) from domestic cheese. Conclusions: Since, the staphylococcal enterotoxins are heat stable, heat had no effect on the toxicity of the enterotoxins within positive samples. Our primer stets confirmed previous studies that introduced PCR as rapid, sensitive, and specific method for dairy products screening system. Our data showed that routine screening and surveillance is vital for different food materials including dairy products.
Molecular and Cellular Probes, 2005
A multiplex PCR for the simultaneous detection of Staphylococcus aureus 23S rRNA, the coagulase and thermonuclease genes as well as the enterotoxin genes sea, sec, sed, seg, seh, sei, sej, sel was developed. The method was used to determine the presence of enterotoxigenic types for 93 S. aureus strains isolated from milk and dairy products. The data obtained by mPCR resulted comparable to those obtained by immunoassay methods. In addition, the mPCR assays also amplified some se genes, whose toxins are undetectable by immunoassay. Multiplex amplification can be obtained starting from 1 pg of DNA, showing the excellent specificity and high sensitivity of the assay. q
Semina: Ciências Agrárias, 2018
This study evaluated the microbiological quality of milk and Coalho cheese, the prevalence of enterotoxin genes, antimicrobial resistance and determined an inducible MLSB resistance phenotype by the D-test in strains of Staphylococcus aureus isolated from these products. Seventy samples of milk and Coalho cheese were analyzed. S. aureus strains were identified by biochemical tests. The presence of se genes (sea-see) was tested by polymerase chain reaction. The antimicrobial sensitivity of S. aureus strains was evaluated for 13 antimicrobial drugs using the disk diffusion technique and the double-disk diffusion test (D-test) was performed to determine inducible resistance to lincosamide phenotype. The amount of toxin sufficient to cause foodborne diseases is generally observed when Staphylococcus populations exceed 105 CFU mL-1 g-1. In this study, none of the milk samples analyzed showed these counts; however, 73.3% (22/30) of Coalho cheese samples exceeded this value. A total of 109...
Arquivos do Instituto Biológico
Food prepared with products derived from animals are involved in most cases of staphylococcal poisoning; therefore, the research of Staphylococcus spp. in Emmental cheese is more applicable. The objective of this study was to identify coagulase-negative Staphylococcus spp. (CNS) in cheese using biochemical and molecular techniques to detect the presence of nine genes responsible for the production of enterotoxins. From 180 samples analyzed, 204 CNS strains were obtained and identified as being 46 (22.6%) S. saprophyticus strains, 27 (13.2%) S. hominis spp. hominis strains, 22 (10.8%) S. sciuri strains, 21 (10.3%) S. xylosus strains, 19 (9.3%) S. epidermidis strains, 19 (9.3%) S. haemolyticus strains, 17 (8.3%) S. lentus strains, 17 (8.3%) S. warneri strains, 11 (5.4%) S. equorum strains and 5 (2.5%) S. cohnni . Using the PCRm protocol, 14 (6.9%) strains with the presence of the genes on the enterotoxin E (SEE)11 (78.6%), J (SEJ) 1 (7%), C (SEC) 1 (7%) and I (SEI) 1 (7%) were detecte...