Age-specific Prevalence of Porcine Reproductive and Respiratory Syndrome Virus, Porcine Circovirus Type 2, and Mycoplasma hyopneumoniae in Korea Pig Farms

Porcine respiratory disease complex (PRDC) continues to be a significant economic problem to the swine industry. Porcine circovirus type 2 (PCV2), porcine reproductive and respiratory syndrome virus (PRRSV), and Mycoplasma hyopneumoniae (MH) are considered to be the most important pathogens that cause PRDC. In this study, we investigated the prevalence of antibodies against PRRSV and MH in the serum of sows and piglets from 89 domestic commercial pig farms by ELISA, and the presence of viral nucleic acids of PRRSV, including North American and European PRRS, and PCV2 was also investigated in the serum of sows and piglets from 89 domestic commercial pig farms by real-time PCR. In case of PRRSV, 78.7% (70/89) of sows were positive for PRRSV antibody, and 96.6% (86/89) of piglets were positive for PRRSV antibody. For MH, 76.4% (68/89) of sows showed positive for MH antibody. In the PRRSV viral nucleic acid detection experiment, 36.0% (32/89) of sows were positive for PRRSV nucleic acids, and virus nucleic acid was detected in 83.1% (74/89) of piglets. In case of virus type, both North American and European types were detected. In case of PCV2, 15.7% (14/89) of sows were positive for PCV2 nucleic acids. Conclusively, PCV2, PRRSV, and MH were widely distributed in pig farms in Korea. These prevalence data related with PRDC provides clinical information for vaccination strategy and development for the control of PRDC.

Antimicrobial Activities of Omija Extracts Against Bacillus cereus and Escherchia coli

Omija berry (Schisandra fructus) is a traditional Korean fruit, which contains lots of medicinal ingredients. In order to analyze whether Omija contains antibacterial components, we extracted Omija using five different methods including water precipitation, ethanol precipitation, hot water extract, methanol-ultrasonication, and water-ultrasonication, and examined their antimicrobial activities against Escherichia coli (E. coli), and Bacillus cereus (B. cereus). Most of Omija extracts did not inhibit bacteria growth in the paper disc diffusion assay except hot water extract for 60 minutes. Hot water extract for 60 minutes made clear inhibition zone around the disc at all the concentrations (x1, x1/10, x1/100) in both E. coli and B. cereus. However, hot water extracts for 90 minutes and 120 minutes showed antimicrobial activities only at x1 stock solution, which indicates that 60 minutes extraction at hot water is the best method to obtain Omija extract with the best antimicrobial activities in disc diffusion assay. In turbidimetric assay, water extract in soak, hot water extract, and methanol extract in ultrasonicator inhibited growth of both E. coli and B. cereus. Ethanol extract in soak and water extract in ultrasonicator had no effect on bacterial growth in both E. coli and B. cereus. In this study, we found that Omija extracts showed antimicrobial activities against E. coli and B. cereus. Therefore, water soluble materials of Omija can be used as a drink supplement and developed as an antibacterial cleanser.

Distributions of Listeria spp., Bacillus spp., Enterococcus spp., Staphylococcus spp., and Coliforms Isolated from Agricultural Herb Products from the Market

The study was conducted to investigate the distribution of pathogenic bacteria related to agricultural herb products that are sold on the market in South Korea. A survey was conducted on the microbial contamination levels and antibiotic susceptibility of Bacillus cereus (B. cereus) among 194 agricultural herb products on sale in Seoul. Distributions of those isolates were 252 coliforms, 148 Bacillus spp., 75 Enterococcus spp., 10 Staphylococcus spp., and 6 Listeria spp., respectively. The number of B. cereus isolates was 34, Escherichia coli isolates was three, Enterococcus faecium isolate was one, and Enterococcus faecalis isolate was one. Antibiotic susceptibility of B. cereus isolates was tested against 36 kinds of antibiotic susceptibility discs by disc diffusion method. B. cereus isolates were resistant to 20 kinds of antibiotics and semi-resistant to 11 kinds of antibiotics. On the basis of these results, any agricultural herb product can be assumed to be resistant or semi-resistant to the antibiotics used in human. In conclusion, we suggest sanitary control and special management regarding B. cereus contamination in agricultural herb products.

Distributions of Bacillus cereus, Pseudomonas, Enterococcus, and coliforms Isolated from Agricultural Products

A survey was conducted on the bacterial contamination levels from 128 agricultural products, and identified 31 coliforms, 34 Bacillus spp., 35 Pseudomonas spp., and 3 Enterococcus spp.. Antibiotic susceptibility testing of eight Escherichia coli (E. coli) isolates, thirteen Bacillus cereus (B. cereus) isolates and seven Pseudomonas aeruginosa (P. aeruginosa) reveled that none of the E. coli isolates shows multidrug resistance pattern. However, one B. cereus isolate was resistant to Amoxicillin/clavulanic acid + Ampicillin/sulbactam + Cephaloxin, and twelve B. cereus isolates were resistant to Amoxicillin/clavulanic acid + Ampicillin/sulbactam + Cephaloxin + Tetracycline. The data from the current study points out that many agricultural products contain multidrug resistant bacteria, and it can be suggested for the need of proper guidelines and special management on the use of antibiotics in agricultural products.

Distributions of Bacillus cereus, Pseudomonas, Enterococcus, and coliforms Isolated from Agricultural Products

A survey was conducted on the bacterial contamination levels from 128 agricultural products, and identified 31 coliforms, 34 Bacillus spp., 35 Pseudomonas spp., and 3 Enterococcus spp.. Antibiotic susceptibility testing of eight Escherichia coli (E. coli) isolates, thirteen Bacillus cereus (B. cereus) isolates and seven Pseudomonas aeruginosa (P. aeruginosa) reveled that none of the E. coli isolates shows multidrug resistance pattern. However, one B. cereus isolate was resistant to Amoxicillin/clavulanic acid + Ampicillin/sulbactam + Cephaloxin, and twelve B. cereus isolates were resistant to Amoxicillin/clavulanic acid + Ampicillin/sulbactam + Cephaloxin + Tetracycline. The data from the current study points out that many agricultural products contain multidrug resistant bacteria, and it can be suggested for the need of proper guidelines and special management on the use of antibiotics in agricultural products.

Molecular Characteristics of Noroviruses Genogroup I and Genogroup II Detected in Patients With Acute Gastroenteritis

Noroviruses are the leading cause of epidemic gastroenteritis, including foodborne outbreak, in Korea. The prevalence of human noroviruses was studied in diarrheal stool samples of patients with acute gastroenteritis by conventional duplex reverse transcription (RT)-PCR. Diarrheal stool samples were collected from 1,685 patients from the local hospitals in Seoul. The prevalence of the noroviruses was 22.8% (222/972 patients) in 2012 and 11.2% (80/713 patients) in 2013, with a total of 17.9% (302/1,685 patients). Genotyping was performed on 302 norovirus-positive stool samples to reveal 5.6% prevalence of genogroup I (GI) (17/302) and 94.4% prevalence of genogroup II (GII) (285/302). The patients with norovirus-associated acute gastroenteritis mostly showed prevalence of GII norovirus, especially GII.4 (64.6%; 195/302).

Epidemiological Investigation of a Measles Outbreak in Seoul, 2013~2014

Korea declared in 2006 that measles had been eliminated; however, a measles outbreak occurred in the southeastern area of Korea in 2011. Active surveillance of measles patients was conducted in Seoul 3 cases were detected in 2013 and 103 cases in 2014. Of 106 confirmed measles patients, 32 cases were within one university in Seongbukgu, and 23 were within three schools in Yongsangu. Students 14~29 years old comprised 78.3% (83/106) of the cases, and 75.5% (80/106) of the measles viruses were of genotype B3. One foreign traveler played an important role in the measles outbreak in Seoul. This measles outbreak in Seoul may provide useful data for future epidemiological studies of measles.

Human Norovirus Genogroups Detected from Acute Gastroenteritis Patients in Seoul from May 2013 to April 2015

Norovirus is an important cause of acute nonbacterial gastroenteritis in communities worldwide. It was evaluated the prevalence of norovirus infections in patients with acute gastroenteritis occurring in Seoul from May 2013 to April 2015, with regular surveillance. 7.3% (252/3,485) of the fecal specimens were determined to be positive for noroviruses by reverse transcription-polymerase chain reaction (RT-PCR). Norovirus genogroup distribution was 19.1% (48/252) genogroup GI, 71.4% (180/252) genogroup GII, and 9.5% (24/252) genogroup G1+GII respectively. It was most norovirus detection rates from November 2013 to March 2015. And it was rotavirus 0.2% (7/3,485), astrovirus 0.03% (1/3,485), sapovirus 0.03% (1/3,485) and, it was non-detective on adenovirus. Norovirus genotypes identified were nine kinds of genogroup GI (GI-1, GI-2, GI-3, GI-4, GI-6, GI-7, GI-8, GI-12, GI-14) and eight kinds of genogroup GII (GII-2, GII-3, GII-4, GII-5, GII-6, GII-7, GII-14, GII-16, GII-17). The genetic characteristics of norovirus and the epidemiological patterns of a viral pathogen from acute gastroenteritis patients may give potentially effective data for epidemiological studies in Seoul, Korea.

Infection Frequency and Mixed infection on Eight Viruses from Patients with Acute Respiratory Syndromes in Seoul

For our survey of the infection frequency and mixed infection of the viruses causing acute respiratory syndromes, we analyzed those viruses from acute respiratory patients in Seoul. Total 1,038 specimens of oropharyngeal swab were tested by the real-time polymerase chain reaction (PCR) kit (Kogenebiotech, Korea) from Jan. to Dec. in 2013. Virus detection rate causing acute respiratory infection was 46% (476/1,038). The most frequently isolated virus was only hRV (21.6%, 103/476), followed by only ADV (8.96%, 93/476), only IFV A (H3N2) (18.1%, 86/476), and only hCoV (7.8%, 37/476) etc. Most of acute respiratory viruses had severe fever. Infection frequency information and mixed infection status on respiratory viruses circulating in Seoul will be helpful for the management of acute respiratory infection and for epidemiological continuous studies.

Prevalence of Human Astrovirus in Patients with Acute Gastroenteritis

The prevalence of human astroviruses was tested in patients with acute gastroenteritis by using conventional duplex reverse transcription (RT)-PCR and electrophoresis. Diarrheal fecal samples were collected from 9,597 patients at local hospitals in Seoul. The prevalence of astroviruses was 1.0% (94/9,597 patients; mostly infants), and that of sapoviruses was 0.1% (14/9,597 patients). Age- and gender-wise analyses were carried out on 29 astrovirus-positive patients having complete information on file regarding their age, gender, and other particulars. The results were higher in patients of ages 0 to 14 yr, and 69.0% of the astrovirus-positive patients were females, of which 69.2% were infants (0 to 12 months), and 61.5% were 1-4 yr old. Notably, in the case of 5 to 78-yr-old acute gastroenteritis patients, 100% were females.

No Detection of Severe Fever with Thrombocytopenia Syndrome Virus from Ixodid Ticks Collected in Seoul

Larvae, nymphs, and adult stages of 3 species of ixodid ticks were collected by tick drag methods in Seoul during June-October 2013, and their infection status with severe fever with thrombocytopenia syndrome (SFTS) virus was examined using RT-PCR. During the period, 732 Haemaphysalis longicornis, 62 Haemaphysalis flava, and 2 Ixodes nipponensis specimens were collected. Among the specimens of H. longicornis, the number of female adults, male adults, nymphs, and larvae were 53, 11, 240, and 446, respectively. Ticks were grouped into 63 pools according to the collection site, species, and developmental stage, and assayed for SFTS virus. None of the pools of ticks were found to be positive for SFTS virus gene.

Antigen Distributions of Rotavirus and Adenovirus Detected by Enzyme Immuno Assay (EIA) from Acute Gastroenteritis Patients in Seoul

Antigen distributions of rotavirus and adenovirus were detected by enzyme immuno assay (EIA) in patients with acute gastroenteritis in Seoul from 2008 to 2012. Tested feces sample numbers from patients were 9,597. Antigen distributions of rotavirus and adenovirus were 13.9%, and 2.1%, respectively. The patterns of each viral pathogen may give potentially effective data for epidemiological studies.

Epidemiological Characterization of Respiratory Viruses Detected from Acute Respiratory Patients in Seoul / 대한임상미생물학회지

BACKGROUND: Viruses that cause acute respiratory infection include adenovirus (ADV), respiratory syncytial virus A and B (RSV(A), RSV(B)), influenza virus A and B (FluA, FluB), parainfluenza virus 1, 2 and 3 (PIV1, PIV2, PIV3), human metapneumovirus (hMPV), human coronavirus (hCoV), human rhinovirus (hRV), and enterovirus, among others. METHODS: Viral incidence was evaluated in acute respiratory patients in Seoul, Korea from 2010 to 2012. A total of 2,544 oropharyngeal swab specimens were tested by real-time polymerase chain reaction (PCR) methods. RNA viruses (hRV, PIV, RSV, hCoV, and hMPV) and DNA viruses (ADV and bocavirus) were detected using the one-step reverse transcriptase PCR (RT-PCR) premix kit (SolGent, Korea) from January 2010 to June 2011, and using the real-time PCR kit (Kogenebiotech, Korea) from July 2011 to December 2012. RESULTS: Thirty-two percent (813/2,544) of specimens were positive; 31.9% (294/923) in 2010, 31.4% (232/738) in 2011, and 32.5% (287/883) in 2012. The most frequently isolated virus was hRV (40.7%, 331/813), followed by ADV (23.9%, 194/813), RSV (14.1%, 115/813), PIV (12.3%, 100/813), and hCoV (8.7%, 71/813). PIV1 was the most commonly isolated PIV, followed by PIV3 and PIV2, respectively. hCo OC43 was the most commonly isolated hCoV, followed by hCoV NL63 and hCoV 229E, respectively. CONCLUSION: Information on respiratory viruses circulating in Seoul, Korea over the last three years will be helpful in the management of acute respiratory infections, and for larger-scale epidemiological studies.