OBJECTIVES: Outbreaks of scarlet fever in Mexico in 1999, Hong Kong and mainland China in 2011, and England in 2014-2016 have received global attention, and the number of notified cases in Korean children, including in Jeju Province, has also increased since 2010. To identify relevant hypotheses regarding this emerging outbreak, an age-period-cohort (APC) analysis of scarlet fever incidence was conducted among children in Jeju Province, Korea. METHODS: This study analyzed data from the nationwide insurance claims database administered by the Korean National Health Insurance Service. The inclusion criteria were children aged ≤14 years residing in Jeju Province, Korea who received any form of healthcare for scarlet fever from 2002 to 2016. The age and year variables were categorized into 5 groups, respectively. After calculating the crude incidence rate (CIR) for age and calendar year groups, the intrinsic estimator (IE) method was applied to conduct the APC analysis. RESULTS: In total, 2345 cases were identified from 2002 to 2016. Scarlet fever was most common in the 0-2 age group, and boys presented more cases than girls. Since the CIR decreased with age between 2002 and 2016, the age and period effect decreased in all observed years. The IE coefficients suggesting a cohort effect shifted from negative to positive in 2009. CONCLUSIONS: The results suggest that the recent outbreak of scarlet fever among children in Jeju Province might be explained through the cohort effect. As children born after 2009 showed a higher risk of scarlet fever, further descriptive epidemiological studies are needed.
Child ; China ; Cohort Effect ; Delivery of Health Care ; Disease Outbreaks ; England ; Epidemiologic Studies ; Exotoxins ; Female ; Hong Kong ; Humans ; Incidence ; Insurance ; Korea ; Methods ; Mexico ; National Health Programs ; Scarlet Fever ; Streptococcus pyogenes

Objective: To analyze the characteristics of super-antigen (SAg) of group A Streptococcus pyogenes (GAS), isolated from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. Methods: Throat swab specimens from patients with scarlet fever or pharyngeal infections were collected and tested for GAS. Eleven currently known SAg genes including SpeA, speC, speG, speH, speI, speJ, speK, speL, speM, smeZ and ssa were tested by real-time PCR while M protein genes (emm genes) were amplified and sequenced by PCR. Results: A total of 377 GAS were isolated from 6 801 throat swab specimens, with the positive rate as 5.5%. There were obvious changes noticed among speC, speG, speH and speK in three years. A total of 45 SAg genes profiles were observed, according to the SAgs inclusion. There were significant differences appeared in the frequencies among two of the highest SAg genes profiles between emm1 and emm12 strains (χ(2)=38.196, P<0.001; χ(2)=72.310, P<0.001). There also appeared significant differences in the frequencies of speA, speH, speI and speJ between emm1 and emm12 strains (χ(2)=146.154, P<0.001; χ(2)=52.31, P<0.001; χ(2)=58.43, P<0.001; χ(2)=144.70, P<0.001). Conclusions: Obvious changes were noticed among SAg genes including speC, speG, speH and speK from patients with scarlet fever or pharyngeal infections in Beijing between 2015-2017. SAg genes including speA, speH, speI and speJ appeared to be associated with the emm 1 and emm 12 strains. More kinds of SAg genes profiles were isolated form GAS but with no significant differences seen in the main SAg genes profiles, during the epidemic period.
Antigens, Bacterial/genetics* ; Bacterial Outer Membrane Proteins ; Bacterial Proteins ; Beijing/epidemiology* ; China/epidemiology* ; Exotoxins ; Female ; Humans ; Membrane Proteins ; Pharyngitis/microbiology* ; Pharynx/microbiology* ; Pregnancy ; Pregnancy Complications, Infectious/microbiology* ; Real-Time Polymerase Chain Reaction ; Scarlet Fever/microbiology* ; Streptococcal Infections ; Streptococcus pyogenes/isolation & purification* ; Superantigens/genetics*

Systemic corticosteroids currently represent the most effective treatment for chronic rhinosinusitis with nasal polyps (CRSwNP), but their long-term use is constrained due to their detrimental side effects. Until recently, development of novel drugs for CRSwNP has been difficult partly due to the absence of a standard animal model of CRSwNP. Exotoxins of Staphylococcus aureus such as staphylococcal enterotoxin B (SEB), are well-known superantigens which can induce a strong immune response; there have been many studies on the association of staphylococcal enterotoxins and development of CRSwNP over the past two decades. Based on previous studies, we invented a mouse model of CRSwNP using SEB. Herein, we explain the protocol development for the mouse model, as well as identify histological and immunological similarities between this mouse model and humans. Furthermore, we describe a study that analyzed the risk factors for CRSwNP such as smoking, and also elaborate on a series of studies that searched for new potential drugs for CRSwNP, including resveratrol, anti-periostin antibody, topical hypoxia-inducible factors, and topical cyclosporine. Based on preceding studies, we have concluded that this mouse model might be a useful tool to investigate the pathophysiology and development of novel drugs for CRSwNP.
Adrenal Cortex Hormones ; Animals ; Cyclosporine ; Enterotoxins ; Exotoxins ; Humans ; Mice* ; Models, Animal ; Nasal Polyps* ; Risk Factors ; Smoke ; Smoking ; Staphylococcus aureus ; Superantigens

Exotoxins produced by Actinobacillus (A.) pleuropneumoniae (Apx) play major roles in the pathogenesis of pleuropneumonia in swine. This study investigated the role of ApxI in hemolysis and cellular damage using a novel apxIA mutant, ApxIA336, which was developed from the parental strain A. pleuropneumoniae serotype 10 that produces only ApxI in vitro. The genotype of ApxIA336 was confirmed by PCR, Southern blotting, and gene sequencing. Exotoxin preparation derived from ApxIA336 was analyzed for its bioactivity towards porcine erythrocytes and alveolar macrophages. Analysis results indicated that ApxIA336 contained a kanamycin-resistant cassette inserted immediately after 1005 bp of the apxIA gene. Phenotype analysis of ApxIA336 revealed no difference in the growth rate as compared to the parental strain. Meanwhile, ApxI production was abolished in the bacterial culture supernatant, i.e. exotoxin preparation. The inability of ApxIA336 to produce ApxI corresponded to the loss of hemolytic and cytotoxic bioactivity in exotoxin preparation, as demonstrated by hemolysis, lactate dehydrogenase release, mitochondrial activity, and apoptosis assays. Additionally, the virulence of ApxIA336 appeared to be attenuated by 15-fold in BALB/c mice. Collectively, ApxI, but not other components in the exotoxin preparation of A. pleuropneumoniae serotype 10, was responsible for the hemolytic and cytotoxic effects on porcine erythrocytes and alveolar macrophages.
Actinobacillus pleuropneumoniae/genetics/*pathogenicity/*physiology ; Animals ; *Apoptosis ; Bacterial Proteins/genetics/metabolism ; Blotting, Southern ; Exotoxins/*genetics ; Hemolysin Proteins/genetics/metabolism ; *Hemolysis ; Macrophages, Alveolar/metabolism/*microbiology ; Polymerase Chain Reaction ; Sequence Analysis, DNA ; Swine ; Virulence

Methcillin-resistant Staphylococcus aureus (MRSA) has emerged as an important cause of community-acquired infections, which has been recently designated as community-associated (CA) MRSA. Panton-Valentine leukocidin (PVL)-negative multilocus sequence type 72 (ST72)-staphylococcal cassette chromosome mec (SCCmec) type IV has been reported as the predominat CA-MRSA strain in Korea and is commonly associated with skin and soft tissue infections in addition to healthcare-associated pneumonia. However, community-acquired pneumonia (CAP) for this strain has not yet been reported. We hereby report two cases of CAP caused by PVL-negative ST72-SCCmec type IV strain in patients who had no risk factors for MRSA acquisition. While CA-MRSA infections are not yet prevalent in Korea, our cases suggest that CA-MRSA should be considered in cases of severe CAP, especially for cases associated with necrotizing pneumonia.
Bacterial Toxins ; Community-Acquired Infections ; Exotoxins ; Humans ; Korea ; Leukocidins ; Methicillin-Resistant Staphylococcus aureus ; Pneumonia ; Risk Factors ; Skin ; Soft Tissue Infections ; Sprains and Strains ; Staphylococcus ; Staphylococcus aureus

Although pandemic community-associated (CA-) methicillin-resistant Staphylococcus aureus (MRSA) ST30 clone has successfully spread into many Asian countries, there has been no case in Korea. We report the first imported case of infection caused by this clone in a Korean traveler returning from the Philippines. A previously healthy 30-yr-old Korean woman developed a buttock carbuncle while traveling in the Philippines. After coming back to Korea, oral cephalosporin was given by a primary physician without any improvement. Abscess was drained and MRSA strain isolated from her carbuncle was molecularly characterized and it was confirmed as ST30-MRSA-IV. She was successfully treated with vancomycin and surgery. Frequent international travel and migration have increased the risk of international spread of CA-MRSA clones. The efforts to understand the changing epidemiology of CA-MRSA should be continued, and we should raise suspicion of CA-MRSA infection in travelers with skin infections returning from CA-MRSA-endemic countries.
Adult ; Bacterial Toxins/metabolism ; Carbuncle/microbiology ; Cephalosporins/therapeutic use ; Community-Acquired Infections/drug therapy/microbiology ; Exotoxins/metabolism ; Female ; Humans ; Leukocidins/metabolism ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus/*isolation & purification ; Philippines ; Republic of Korea ; Staphylococcal Skin Infections/*drug therapy/surgery ; Travel ; Vancomycin/therapeutic use

In the present study, we investigated the effect of Tetaus toxin (TeT) on cell proliferation and neuroblast differentiation using specific markers: 5-bromo-2-deoxyuridine (BrdU) as an exogenous marker for cell proliferation, Ki-67 as an endogenous marker for cell proliferation and doublecortin (DCX) as a marker for neuroblasts in the mouse hippocampal dentate gyrus (DG) after TeT treatment. Mice were intraperitoneally administered 2.5 and 10 ng/kg TeT and sacrificed 15 days after the treatment. In both the TeT-treated groups, no neuronal death occurred in any layers of the DG using neuronal nuclei (NeuN, a neuron nuclei maker) and Fluoro-Jade B (F-J B, a high-affinity fluorescent marker for the localization of neuronal degeneration). In addition, no significant change in glial activation in both the 2.5 and 10 ng/kg TeT-treated-groups was found by GFAP (a marker for astrocytes) and Iba-1 (a marker for microglia) immunohistochemistry. However, in the 2.5 ng/kg TeT-treated-group, the mean number of BrdU, Ki-67 and DCX immunoreactive cells, respectively, were apparently decreased compared to the control group, and the mean number of each in the 10 ng/kg TeT-treated-group was much more decreased. In addition, processes of DCX-immunoreactive cells, which projected into the molecular layer, were short compared to those in the control group. In brief, our present results show that low dosage (10 ng/kg) TeT treatment apparently decreased cell proliferation and neuroblast differentiation in the mouse hippocampal DG without distinct gliosis as well as any loss of adult neurons.
Adult ; Animals ; Bromodeoxyuridine ; Cell Proliferation ; Dentate Gyrus ; Exotoxins ; Fluoresceins ; Gliosis ; Humans ; Immunohistochemistry ; Mice ; Neurogenesis ; Neurons ; Tetanus ; Tetanus Toxin

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important nosocomial pathogens worldwide. This study was performed to investigate the characterization of MRSA isolated from healthy persons in Gwangju area. A total of 404 nasal swab samples was collected during October 2011 and May 2012 in Gwangu, Korea. A survey on MRSA was conducted with meat distributors (n=230), pre-school children (n=108), officers (n=66), respectively. To confirm the MRSA, polymerase chain reaction (PCR) for the S. aureus specific gene and mecA gene was performed. A total of 34 (8.4%) MRSA isolates was isolated from 404 nasal swab samples: 6.1% (14/230) from meat distributors, 16.7% (18/108) from pre-school children, and 3.0% (2/66) from officers samples, respectively. The most prevalent antimicrobial resistance observed in the MRSA isolates was to ampicillin 100% (34/34), followed by penicillin 97.1% (33/34), oxacillin 94.1% (32/34) and erythromycin 52.9% (18/34). All MRSA isolates were then characterized by panton-valentine leukocidin (pvl) gene detected by PCR, staphylococcal cassette chromosome mec (SCCmec) typing, and pulsed-field gel electrophoresis (PFGE) with Sma I digestion. 34 MRSA isolates from nasal carriage were pvl gene negative, SCCmec type IV; 73.5% (25/34), type II; 17.6% (6/34), type III; 2.9% (1/34), and untypable; 5.9% (2/34), respectively. 34 MRSA isolates showed 16 PFGE patterns. These results indicated that isolation rates of community-associated methicillin-resistant S. aureus (CA-MRSA) from healthy persons were low (8.4%), but continuous surveillance and monitoring should be performed to prevent the spread of MRSA in the community.
Adenosine ; Ampicillin ; Bacterial Toxins ; Child ; Digestion ; Electrophoresis, Gel, Pulsed-Field ; Erythromycin ; Exotoxins ; Humans ; Korea ; Leukocidins ; Meat ; Methicillin Resistance ; Methicillin-Resistant Staphylococcus aureus ; Oxacillin ; Penicillins ; Polymerase Chain Reaction

Superantigens are potent immunostimulatory exotoxins well known to be produced by Staphylococcus aureus (S. aureus). These exotoxins have capacity to act as superantigens by binding with the variable beta(Vbeta) region of lymphocytes in chronic rhinosinusitis with nasal polyposis, bypassing normal antigen processing and directly stimulating a massive inflammatory response. Accumulated evidence is now convincing that S. aureus superantigens may play an important role in development of chronic rhinosinusitis with nasal polyposis which are thought to skew the cytokine response towards a Th2 phenotype inducing eosinophilia and the production of polycolonal IgE. This review summarizes the current evidence of characteristics and its role superantigens in pathophysiology of nasal polyposis.
Antigen Presentation ; Eosinophilia ; Exotoxins ; Immunoglobulin E ; Lymphocytes ; Nasal Polyps ; Phenotype ; Staphylococcus aureus ; Superantigens

Superantigens are potent immunostimulatory exotoxins well known to be produced by Staphylococcus aureus (S. aureus). These exotoxins have capacity to act as superantigens by binding with the variable beta(Vbeta) region of lymphocytes in chronic rhinosinusitis with nasal polyposis, bypassing normal antigen processing and directly stimulating a massive inflammatory response. Accumulated evidence is now convincing that S. aureus superantigens may play an important role in development of chronic rhinosinusitis with nasal polyposis which are thought to skew the cytokine response towards a Th2 phenotype inducing eosinophilia and the production of polycolonal IgE. This review summarizes the current evidence of characteristics and its role superantigens in pathophysiology of nasal polyposis.
Antigen Presentation ; Eosinophilia ; Exotoxins ; Immunoglobulin E ; Lymphocytes ; Nasal Polyps ; Phenotype ; Staphylococcus aureus ; Superantigens