• Biomedical Science Letters
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• v.7 no.2
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• pp.85-89
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• 2001

Many Staphylococcus aureus strains produce enterotoxins causing food poisoning. Staphylococcal enterotoxins are classified by serological criteria into five major groups - subtype A to E. It is difficult, time-consuming, and expensive to detect staphylococcal enterotoxins in the clinical laboratory. In this study, we fried to detect the enterotoxin genes of Staphylococcus aureus strains isolated from clinical specimens and Kimbap - rice rolled in a sheet of laver - using multiplex PCR technique. A total of 77 strains of Staphylococcus aureus from clinical specimens and 78 strains from Kimbap were isolated. Among clinical isolates of S. aureus, 60 strains (78.0%) were identified as producing enterotoxins. A total offs strains (91.6%) in the 60 staphylococcal enterotoxin producing strains were enterotoxin subtype C. In case of kimbap: 43 (55.1%) strains were detected to produce enterotoxins and 39 (90.6%) enterotoxin producing strains were subtype A.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.553-558
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• 1998

Using the previous established multiplex PCR (mPCR), the presence of six kinds of staphylococcal superantigen (SAg) genes was investigated for nineteen Staphylococcus aureus isolates from the commercialized meat sources. As a result, only one isolate from pork among 19 S aureus isolates (5.3%) was confirmed as a potential SAg producer and harbored sec gene. The results in this study suggest that meat may not be major contagion of staphylococcal food poisoning (SFP) in Korea and that staphylococcal enterotoxin type C may be associated with the disease. Also, the mPCR method in this study can be a useful genotypic method which can overcome the typical disadvantages of conventional antibody-based methods due to antigenic homology, and furthur survey on food-borne S aureus isolates can provide the important epidemiological data for SFP in Korea.

• Biomedical Science Letters
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• v.20 no.1
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• pp.25-31
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• 2014

Atopic dermatitis (AD) is an inflammatory, relapsing, chronic skin disease and lesions in AD are frequently colonized with Staphylococcus aureus (S. aureus). Activation of T cells and IgE production by staphylococcal enterotoxins B (SEB) plays a crucial role in the pathogenesis of AD. Enterococcus faecalis (E. faecalis) is a nonpathogenic bacterium and produces the probiotic products that have been shown to have inhibitory effects on inflammatory responses. In present study, we carried out to assess the anti-inflammatory role of lyzed E. faecalis against the damaging effects of SEB on AD related immune responses. Furthermore, we attempted to determine whether the co-cultured lyzed E. faecalis can influence the colonization of S. aureus. As a result, we identified the effect of E. faecalis lysate as a potent therapeutic agent for atopic dermatitis (AD). E. faecalis lysate reduces the productions of total IgE and cytokines of AD-related immune cells in response to SEB stimulation. The proliferation of S. aureus was also inhibited by E. faecalis lysate. In conclusions, E. faecalis lysate may improve the skin-defense system disturbed by atopic condition, and may prevent subsequent secondary infection of S. aureus and development of AD.

• Animal Bioscience
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• v.34 no.4
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• pp.734-742
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• 2021

Objective: The present study aimed to investigate the occurrence and species of coagulase-positive staphylococci (CoPS) and coagulase-negative staphylococci (CoNS) in retail pork meat samples collected during nationwide monitoring. The staphylococcal isolates were characterized for antimicrobial and zinc chloride resistance and enterotoxigenic potential. Methods: A total of 260 pre-packaged pork meat samples were collected from 35 retail markets in 8 provinces in Korea for isolation of staphylococci. Antimicrobial and zinc chloride resistance phenotypes, and genes associated with the resistance phenotypes were determined on the isolates. Furthermore, the presence and distribution of 19 staphylococcal enterotoxin (SE) genes and enterotoxin-like genes among the pork-associated staphylococci were determined by multiplex polymerase chain reaction-based assays using the specific primer sets. Results: A total of 29 staphylococcal strains (29/260, 11.1%) were isolated from samples of retail pork meat, 24 (83%) of which were CoNS. The four CoNS species identified were S. saprophyticus (n = 16, 55%), S. sciuri (n = 3, 10%), S. warneri (n = 3, 10%), and S. epidermidis (n = 2, 7%). Among the 29 isolates, four methicillin-resistant CoNS (MR-CoNS; three S. sciuri and one S. epidermidis) and one methicillin-resistant CoPS (MR-CoPS; one S. aureus) were identified. In addition, a relatively high level of tetracycline (TET) resistance (52%) was confirmed in CoNS, along with a predominant distribution of tet(K). The most prevalent SEs were sep (45%), and sen (28%), which were carried by 81% of S. saprophyticus. Conclusion: These findings suggest that CoNS, especially S. saprophyticus strains, in raw pork meat could be a potential risk factor for staphylococcal food poisoning (SFP), and therefore, requires further investigation to elucidate the role of SEls in SFP and virulence of the pathogen. Our results also suggest that CoNS from raw pork meat may act as a source for transmission of antimicrobial resistance genes such as staphylococcal cassette chromosome mec and tet(K).

• Korean Journal of Veterinary Research
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• v.39 no.4
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• pp.806-810
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• 1999

A multiplex-polymerase chain reaction (PCR) assay was used to detect staphylococcal enterotoxin production by 12 strains of Staphylococcus aureus isolated from clinical specimens. To evaluate the efficacy and/or sensitivity of this method, the results were compared to those obtained with the reversed passive latex agglutination kit (SET-RPLA, Denka Seiken, Japan). Of 10 strains positive by PCR were positive by RPLA but two strains, representing high sensitivity of the former method. Enterotoxin B was the most prevalent by the two methods. The kappa index between the two methods was 0.826, indicating a higher agreement and fully reliable for use. These results would suggest that sensitive, inexpensive, and relatively rapid multiplex-PCR technique may be an effective means for the detection of staphylococcal enterotoxin genes as an alternative to traditional methods such as kits or immunological methods, which depend upon the amount of enterotoxin produced.

• Biomedical Science Letters
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• v.20 no.2
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• pp.96-102
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• 2014

Staphylococcal enterotoxin B (SEB) is bacterial toxin that induces the activation of immune cells. Because the inhibition of pro-inflammatory effect of SEB can resolve the inflammation, I determined the influence of functional or structural change of SEB on immune cells. The post translational modification of protein occurs through carbamylation. Carbamylation can change the structure of proteins and can modify the biological activity of protein. In the present study, I investigated the effect of carbamylated SEB (CSEB) on the inflammatory response mediated by LPS in HL-60 cells. To determine the anti-inflammatory effect of CSEB, I produced carbamylated SEB using potassium cyanate (KCN) and then examined whether CSEB involved in cytokine releases and apoptosis of LPS-stimulated HL-60 cells. Although CSEB had not any effect on the LPS-stimulated HL-60 cells, the protein levels of IL-8, TNF-${\alpha}$ and IL-$1{\beta}$ were significantly decreased by CSEB without cytotoxicity. CSEB also blocked Akt and NF-${\kappa}B$ activation. These results indicate that the suppressive effect of CSEB in LPS-stimulated cytokine releases is occurred by inhibition of Akt and NF-${\kappa}B$ activity. Through further studies, CSEB may be used as anti-inflammatory molecule that makes the immune system more efficient.

• Korean Journal of Clinical Laboratory Science
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• v.40 no.1
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• pp.48-54
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• 2008

Nine types of staphylococcal enterotoxin (SE) genes (sea~see, seg~sej), 3 types of virulence genes (eta, etb, tst), mecA and 16S rRNA as internal positive control were detected from 187 clinical MRSA (methicillin resistance Staphylococcus aureus) strains isolated from a variety hospitalized patients in Daegu and Gyeongsangbuk-do areas using the multiplex PCR. The frequency of the S. aureus strains harboring recently reported SE genes (seg~sej) were found to be very high (65.9%) and greater than that of the strains harboring classical SE (sea~see) genes (47.8%) as previously established. Taking into account that the newly described pairs form SE genes (i.e., sec+seg+sei, seg+sei) were many, in the other hand, single form SE genes (i.e., seg, seh, sei and sej) were rarely detected. The S. aureus with pairs form enterotoxigenic genes become more potentially toxigenic strains. Furthermore, this work indicated a systematic association between the seg and sei genes and their high incidence among the S, aureus strains, which suggests that these two SE's could be an important phylogenetic link among the staphylococcal enterotoxins.

• Journal of Food Hygiene and Safety
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• v.16 no.3
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• pp.159-167
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• 2001

Staphylocorccus aureus is gram positive, facultatively anaerobic, non-sporulative coccus, and positive for coagulase and DNase. The food-poisoning outbreak of Staphylococcus aureus increases in the world, and third occurrence happened in our country. Of 105 isolates (25.4%) obtained 413 focal samples of food-poisoning suspicious patients. In those cases, the enterotoxins were detected from a total of 45 isolates (42.9%), 9 isolates(20.0%) were A type, 33 isolates (73.3%) were H types, 2 isolates (4.4%) were G type and 1 isolate was a I type enterotoxin. Among the isolates possessing staphylococcal enterotoxins, 29 isolates had H type only(64.4%), 5 isolates had A type only and 4 isolates had both A and H type. Two isolates had G type only and 1 isolate had I type only. In the antibiotic susceptibility, 48 isolates (46%) had at least one antibiotic resistance among 105 isolates, 34 isolates (70.8%) were resistant to penicillin. 1 isolate (2.1%) to ampicillin, 3 isolates (6.3%) to erythromycin and kanamycin. Seven were resistant to more than two antibiotics and especially 1 isolate was resistant to penicillin-ampicillin-nitrofurantoin.

• Journal of Food Hygiene and Safety
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• v.34 no.6
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• pp.576-582
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• 2019

Staphylococcus pseudintermedius is an opportunistic pathogen in dogs and is recognized as a zoonotic pathogen causing public health concern. Although canine-associated S. pseudintermedius has mainly been recognized for its antimicrobial resistance and ability to cause skin infections in dogs, information on antimicrobial resistance profiles and enterotoxigenicity of S. pseudintermedius in livestock is very limited. In this study, we investigated the prevalence of 18 different staphylococcal enterotoxin (SE) genes and toxic shock syndrome toxin gene (tst-1) in S. pseudintermedius strains isolated from dogs, pigs, and beef cattle. Moreover, antimicrobial resistance profiles of the strains were determined along with the presence of mecA and SCCmec types. Except for one bovine isolate, all S. pseudintermedius isolates from dogs and pigs were resistant to multiple drugs (≥ 4 different drugs). Four out of six canine isolates were methicillin resistant and carried SCCmec type V. In addition, 11 different SE genes (seb, sec, see, seg, sei, sej, sel, seo, sep, seq, and seu) and tst-1 were identified in S. pseudintermedius isolates from dogs, pigs, and beef cattle. Most S. pseudintermedius isolates (83%) harbored multiple SE genes, and sel (42%) and sep (42%) were most frequently detected in the isolates. Our results suggested that S. pseudintermedius isolates from livestock and companion animals may serve as a reservoir for SE genes and antimicrobial resistance.

• Journal of Veterinary Science
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• v.24 no.6
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• pp.85.1-85.13
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• 2023

Background: A recent increase in the occurrence of canine skin and soft tissue infections, including otitis externa and pyoderma, caused by antimicrobial-resistant Staphylococcus pseudintermedius and S. schleiferi has become a significant public and veterinary health issues. Objective: We investigated the virulence potentials associated with the occurrence of canine otitis externa in S. pseudintermedius and S. schleiferi. Methods: In this study, the prevalence of genes encoding leukocidins, exfoliative toxins, and staphylococcal enterotoxins (SEs) was investigated using previously characterized S. pseudintermedius (n = 26) and S. schleiferi (n = 19) isolates derived from canine otitis externa. Susceptibility to cathelicidins (K9CATH and PMAP-36) and hydrogen peroxide (H₂O₂) was also examined in both staphylococcal species. Results: A high prevalence of genes encoding leukocidins (lukS/F-I, lukS1/F1-S, and lukS2/F2-S), exfoliative toxins (siet, expB, and sset), and SEs was identified in both S. pseudintermedius and S. schleiferi isolates. Notably, S. pseudintermedius isolates possessed higher number of SE genes, especially newer SE genes, than S. schleiferi isolates harboring egc clusters. Although no significant differences in susceptibility to K9CATH and H₂O₂ were observed between the two isolate groups, S. pseudintermedius isolates exhibited enhanced resistance to PMAP-36 compared to S. schleiferi isolates. Conclusions: These findings suggest that high a prevalence of various toxin genes together with enhanced resistance to cathelicidins may contribute to the pathogenicity of S. pseudintermedius and S. schleiferi in canine cutaneous infections.