Search results for: enterotoxins

Authors: Stéfani T. A. Dantas, Laura T. S. Takume, Bruna F. Rossi, Érika R. Bonsaglia, Ivana G. Castilho, José C. F. Pantoja, Ary Fernandes Júnior, Juliano L. Gonçalves, Marcos V. Santos, Rinaldo A. Mota, Vera L. M. Rall

Abstract:

Staphylococcus aureus is one of the main pathogens causing contagious bovine mastitis, being more frequently isolated from subclinical form, although the clinical form also occurs. Clinical mastitis cause visual signs, such as swelling, fever, hardening of the mammary gland, or any change in the characteristics of the milk. Considering the subclinical type, there are no visible signs in the animal nor changes in the milk. S. aureus has many important virulence factors for the establishment of its pathogenicity in animals, such as enterotoxins, which are also responsible for foodborne poisoning. Our objective is to perform a comparative analysis between 103 isolates of S. aureus, obtained from the milk of cows with clinical mastitis and 103 more, from subclinical type, in relation to the presence of these enterotoxins and verify if their presence plays an important role in the signs of illness. We will investigate all enterotoxins described till now, such as sea-see, seg-sez, sel26, sel 27, se01, and se02 (This study was approved by the Sao Paulo State University Animal Use Ethics Committee, No. 0136/2017). For the PCR assay, we used Illustra Bacteria Mini Spin Kit for bacterial DNA. At this moment, we have already tested sea-see, seg-ser, sew, and sex, and the results have already been submitted to Fisher Exact Probability Test or Chi-square Test. Considering the isolates obtained from clinical mastitis, the most frequent enterotoxins were selw (99%), selx (78%) and selh (50.5%), and sec, see, sej, sell, selp,and ser were absent. Among the subclinics, selw (82.5%) selm (15.5%) and selx (14.6%) were the most frequent, and sea-see, seg, sei-sel, sem-ser were absent. We have already observed statistically significant differences for seb, seg, seh, sei, selo, selu, selw and selx. Other interesting results were the low number of genes in each isolate from subclinical mastitis [0 genes: 14 (13.6%); 1 gene: 55 (53.4%); 2 genes: 33 (32%) or 3: 1 (0.97%)] compared to clinical isolates [1 gene: 5 (4.9%); 2 genes: 29 (28.1%); 3 genes: 38 (36.9%); 4 genes: 14 (13.6%); 5 genes: 5 (4.9%); 6 genes: 4 (3.9%); 7 genes: 5 (4.9%); 8 genes: 2 (1.9%) and 9 genes: 1 (1%)]. Based on these results, we can conclude that enterotoxins indeed play an important role in clinical signs in cattle with mastitis.

Keywords: mastitis, S. aureus, PCR, staphylococcal enterotoxin

Procedia PDF Downloads 67

Authors: Marija Ratkova Manovska, Mirko Prodanov, Dean Jankuloski, Katerina Blagoevska

Abstract:

Staphylococci, which are widely found in the environment, animals, humans, and food products, include Staphylococcus aureus (S. aureus), the most significant pathogenic species in this genus. The virulence and toxicity of S. aureus are primarily attributed to the presence of specific genes responsible for producing toxins, biofilms, invasive components, and antibiotic resistance. Staphylococcal food poisoning, caused by the production of staphylococcal enterotoxins (SEs) by these strains in food, is a common occurrence. Globally, S. aureus food intoxications are typically ranked as the third or fourth most prevalent foodborne intoxications. For this study, a total of 333 milk samples and 1160 dairy product samples were analyzed between 2016 and 2020. The strains were isolated and confirmed using the ISO 6888-1:1999 "Horizontal method for enumeration of coagulase-positive staphylococci." Molecular analysis of the isolates, conducted using conventional PCR, involved detecting the 23s gene of S. aureus, the nuc gene, the mecA gene, and 11 genes responsible for producing enterotoxins (sea, seb, sec, sed, see, seg, seh, sei, ser, sej, and sep). The 23s gene was found in 93 (75.6%) out of 123 isolates of Staphylococcus spp. obtained from milk. Among the 76 isolates from dairy products, either S. aureus or the 23s gene was detected in 49 (64.5%) of them. The mecA gene was identified in three isolates from raw milk and five isolates from cheese samples. The nuc gene was present in 98.9% of S. aureus strains from milk and 97.9% from dairy products. Other Staphylococcus strains carried the nuc gene in 26.7% of milk strains and 14.8% of dairy product strains. Genes associated with SEs production were detected in 85 (69.1%) strains from milk and 38 (50%) strains from dairy products. In this study, 10 out of the 11 SEs genes were found, with no isolates carrying the see gene. The most prevalent genes detected were seg and sei, with some isolates containing up to five different SEs genes. These findings indicate the presence of enterotoxigenic staphylococci strains in the tested samples, emphasizing the importance of implementing proper sanitation and hygienic practices, utilizing safe raw materials, and ensuring adequate handling of finished products. Continued monitoring for the presence of SEs is necessary to ensure food safety and prevent intoxication.

Keywords: dairy products, milk, Staphylococci, enterotoxins, SE genes

Procedia PDF Downloads 40

Authors: V. Verma, Syed Riyaz-ul-Hassan

Abstract:

Staphylococcus aureus is one of the most commonly found pathogenic bacteria and is hard to eliminate from the human environment. It is responsible for many nosocomial infections, besides being the main causative agent of food intoxication by virtue of its variety of enterotoxins. Routine detection of S. aureus in food is usually carried out by traditional methods based on morphological and biochemical characterization. These methods are time-consuming and tedious. In addition, misclassifications with automated susceptibility testing systems or commercially available latex agglutination kits have been reported by several workers. Consequently, there is a need for methods to specifically discriminate S. aureus from other staphylococci as quickly as possible. Data on protocols developed using molecular means like PCR technology will be presented for rapid and specific detection of this pathogen in food, clinical and environmental samples, especially milk.

Keywords: food Pathogens, PCR technology, rapid and specific detection, staphylococcus aureus

Procedia PDF Downloads 491

Authors: Çiğdem Sezer, Aksem Aksoy, Leyla Vatansever

Abstract:

This study has been done for the purpose of evaluation of public health and identifying of enterotoxigenic Staphyloccocus aureus in kitchen of catering. In the kitchen of catering, samples have been taken by swabs from surface of equipments which are in the salad section, meat section and bakery section. Samples have been investigated with classical cultural methods in terms of Staphyloccocus aureus. Therefore, as a 10x10 cm area was identified (salad, cutting and chopping surfaces, knives, meat grinder, meat chopping surface) samples have been taken with sterile swabs with helping FTS from this area. In total, 50 samples were obtained. In aseptic conditions, Baird-Parker agar (with egg yolk tellurite) surface was seeded with swabs. After 24-48 hours of incubation at 37°C, the black colonies with 1-1.5 mm diameter and which are surrounded by a zone indicating lecithinase activity were identified as S. aureus after applying Gram staining, catalase, coagulase, glucose and mannitol fermentation and termonuclease tests. Genotypic characterization (Staphylococcus genus and S.aureus species spesific) of isolates was performed by PCR. The ELISA test was applied to the isolates for the identification of staphylococcal enterotoxins (SET) A, B, C, D, E in bacterial cultures. Measurements were taken at 450 nm in an ELISA reader using an Ridascreen-Total set ELISA test kit (r-biopharm R4105-Enterotoxin A, B, C, D, E). The results were calculated according to the manufacturer’s instructions. A total of 50 samples of 97 S. aureus was isolated. This number has been identified as 60 with PCR analysis. According to ELISA test, only 1 of 60 isolates were found to be enterotoxigenic. Enterotoxigenic strains were identified from the surface of salad chopping and cutting. In the kitchen of catering, S. aureus identification indicates a significant source of contamination. Especially, in raw consumed salad preparation phase of contamination is very important. This food can be a potential source of food-borne poisoning their terms, and they pose a significant risk to consumers have been identified.

Keywords: Staphylococcus aureus, enterotoxin, catering, kitchen, health

Procedia PDF Downloads 364