Epidemiological Characteristics of Field Tick-Borne Pathogens in Gwang-ju Metropolitan Area, South Korea, from 2014 to 2018

ObjectivesThe importance of tick-borne diseases is increasing because of climate change, with a lack of long-term studies on tick-borne pathogens in South Korea. To understand the epidemiological characteristics of tick-borne diseases, the monthly distribution of field ticks throughout the year was studied in South Korea between May 2014 and April 2018 in a cross sectional study.MethodsThe presence of various tick-borne pathogens (Rickettsia species, Borrelia species, Anaplasma phagocytophilum) was confirmed by using polymerase chain reaction, to provide information for a prevention strategy against tick-borne pathogenic infections, through increased understanding of the relationship between seasonal variation and risk of infection with Rickettsia species. This was performed using logistic regression analysis (SPSS 20, IBM, USA) of the data obtained from the study.ResultsDuring the study period there were 11,717 ticks collected and 4 species identified. Haemapysalis longicornis was the most common species (n = 10,904, 93.1%), followed by Haemapysalis flava (n = 656, 5.6%), Ixodes nipponensis (n = 151, 1.3%), and Amblyomma testudinarium (n = 6, 0.05%) The results of this cross-sectional study showed that Haemapysalis flava carried a higher risk of transmission of Rickettsia species than other tick species (p < 0.05).ConclusionIn conclusion, due attention should be paid to preventing tick-borne infections in humans whilst engaged in outdoor activities in Spring and Autumn, particularly in places where there is a high prevalence of ticks.

Epidemiological Characteristics of Rodents and Chiggers with Orientia Tsutsugamushi in the Republic of Korea

A survey of rodents and chiggers associated with Orientia tsutsugamushi was conducted in a rural region of the Republic of Korea (Korea) between 2014 and 2018. Overall Apodemus agrarius 15.2% had the highest seropisitive for O. tsutsugamushi, followed by Myodes regulus 11.4%. Monthly risk factors using logistic regression analysis were not associated with O. tsutsugamushi infections in rodents. The overall prevalence rate of O. tsutsugamushi among chiggers was 0.3%. The chigger (Leptotrombidium scutellare) and monthly (October) risk factors were associated with O. tsutsugamushi human infections (P<0.05). Orientia tsutsugamushi infections are endemic in rodents in Korea and people, for example, soldiers who are active outdoors, must employ preventive measures, especially during October (P<0.05). When there are many reports of O. tsutsugamushi infections in Korea. The Boryong strain 85.7% (2/14) was the most common strain detected in chiggers, followed by the Shimokoshi 7.1% (1/14) and Karp 7.1% strains.

Short-term Clinical Outcomes of Micropulse TransscleralCyclophotocoagulation in Refractory Glaucoma Patients

Purpose@#We evaluated the efficacy and safety of micropulse transscleral cyclophotocoagulation (MP-TSCPC) in refractoryglaucoma patients. @*Methods@#A retrospective chart review was performed for 23 eyes of 23 patients with refractory glaucoma who were followed for6 months after MP-TSCPC. @*Results@#The mean preoperative intraocular pressure (IOP) was 39.3 ± 15.8 mmHg and the mean number of antiglaucoma medicationswas 2.6 ± 0.6. Both significantly decreased at 6 months to 23.8 ± 15.4 mmHg (p = 0.002) and 1.8 ± 1.1 (p = 0.018).Surgical success was defined as a postoperative IOP decrease from 6-21 mmHg or more than 20% reduction from baseline. Thesuccess rate was 65.2% at 6 months. Complications of MP-TSCPC included subconjunctival hemorrhage in 6 eyes (26.1%), ocularpain in 16 eyes (69.6%), anterior chamber inflammation in 17 eyes (73.9%), and hypotony in 2 eyes (8.7%). @*Conclusions@#MP-TSCPC in patients with refractory glaucoma showed a reduction in IOP and the number of antiglaucoma medicationsin the short-term. However, additional studies are needed to determine the optimal laser settings for maximum efficacyand safety.

Molecular Epidemiology of Viral Conjunctivitis in the Southern Region of South Korea, 2012–2016

Epidemic keratoconjunctivitis (EKC) and acute hemorrhagic conjunctivitis (AHC) are common diseases caused by human adenoviruses (HAdV) and enteroviruses, respectively, in South Korea. However, there are limited studies on the molecular epidemiology of viral conjunctivitis in South Korea. The main objective of this study was to characterize the genotypes of adenoviruses and enteroviruses causing viral conjunctivitis in the southwest region of South Korea. We collected conjunctival swabs from 492 patients with suspected cases of viral conjunctivitis from 6 ophthalmic hospitals in Gwangju Metropolitan City, in South Korea, between 2012 and 2016. Of the 492 samples tested, HAdVs and enteroviruses were detected in 249 samples (50.6%) and 19 samples (3.9%), respectively. The genotype analysis detected HAdV-8 in 183 samples (73.5%), HAdV-37 in 14 samples (5.6%), and HAdV-3, and HAdV-4 in 9 samples (3.6%) each. We detected coxsackievirus A24 (CVA24) and coxsackievirus B1 (CVB1) in 8 samples (42.0%) and 4 samples (21.0%), respectively. We also reported for the first time HAdV-56-infected cases of EKC in South Korea. Furthermore, we found three cases of coinfection with HAdV and enterovirus genotypes in our samples. HAdV-8 and CVA24, the main causes of EKC and AHC, respectively, worldwide, were also found to be the predominant genotypes in our study.

The Genetic Diversity of Norovirus from Children with Diarrhea in Gwangju Metropolitan City, Korea: 2008-2012

In order to study the characteristics of norovirus in Gwangju metropolitan city, We examined norovirus in 13,931 fecal specimens collected through five years (2008-2012) from children admitted with a chief complain of acute diarrhea. Among a total of norovirus (NoV) was most frequently detected (3,025 cases, 21.7%). Concerning the frequency of virus detected by month, NoV tended to break out frequently from October to March in the following year. NoV was detected most highly in 0~3 year infants. Through examinations on NoV genotypes, among 3,025 cases that turned out to be positive, the genotypes of 2,652 cases were determined with various results including 13 types of GI and 17 types of GII. The results of analysis on GI genotypes were as follows: GI-4 (21.9%), GI-2 (15.2%), and GI-6 (10.5%). GII genotypes were as follows: GII-4 (63.9%), GII-3 (18.9%), GII-8 (4.2%), GII-2 (3.9%), GII-6 (3.3%), and GII-1 (1.9%). Eight types of variants for GII-4 genotype (427 cases) were identified. The majority of the GII-4 variants was GII-4_Farmington (181 cases, 42.4%), which peaked in 2012, while GII-4_2008b (173 cases, 40.5%) showed a high prevalence in 2011. Concerning the circulation of variants, as many as eight types of GII-4 variants were identified in 2012, showing more varieties than in other years. Therefore, this study can be used as fundamental data for the development of vaccine candidate for the prevention of viral diarrheal diseases with high-incidence.

Seroepidemiological Survey of Zoonotic Diseases in Small Mammals with PCR Detection of Orientia tsutsugamushi in Chiggers, Gwangju, Korea

Serosurveillance for zoonotic diseases in small mammals and detection of chiggers, the vector of Orientia tsutsugamushi, were conducted from September 2014 to August 2015 in Gwangju Metropolitan Area. Apodemus agrarius was the most commonly collected small mammals (158; 91.8%), followed by Myodes regulus (8; 4.6%), and Crocidura lasiura (6; 3.5%). The highest seroprevalence of small mammals for O. tsutsugamushi (41; 26.3%) was followed by hantaviruses (24; 15.4%), Rickettsia spp. (22; 14.1%), and Leptospira (2; 1.3%). A total of 3,194 chiggers were collected from small mammals, and 1,236 of 3,194 chiggers were identified with 7 species of 3 genera: Leptotrombidium scutellare was the most commonly collected species (585; 47.3%), followed by L. orientale (422; 34.1%), Euchoengastia koreaensis (99; 8.0%), L. palpale (58; 4.7%), L. pallidum (36; 2.9%), Neotrombicula gardellai (28; 2.3%), and L. zetum (8; 0.6%). L. scutellare was the predominant species. Three of 1,236 chigger mites were positive for O. tsutsugamushi by PCR. As a result of phylogenetic analysis, the O. tsutsugamushi strain of chigger mites had sequence homology of 90.1-98.2% with Boryong. This study provides baseline data on the distribution of zoonotic diseases and potential vectors for the development of prevention strategies of vector borne diseases in Gwangju metropolitan area.

Molecular Epidemiology of Mumps Virus Circulated in Gwangju

The recent mumps epidemic in South Korea has generated a large amount of public concern. This study has attempted to analyze molecular epidemiological changes of mumps virus circulating in Gwangju metropolitan area, South Korea. 953 throat swab samples were collected from patients with parotitis from May 2013 to July 2014. The majority (71.5%) of these cases have occurred in middle or high school students aged from 15 to 19 years. All samples were tested using a reverse transcription polymerase chain reaction (RT-PCR) that targets the short hydrophobic (SH) gene of the virus. Mumps virus SH gene was detected in 39.2% (374/953) of samples. And 82 RT-PCR products were randomly selected for nucleotide sequencing analysis. All of these sequences were determined as genotype I by phylogenetic analysis and showed the highest nucleic acid similarity (99%) with Dg1062/Korea/98 (GenBank accession no. AY309060). These results suggested that appearance of new genotype or genetic variation at the nucleotide level could be ruled out to evaluate main cause of recent mumps outbreak in Gwangju metropolitan area.

The Molecular Epidemiology of Circulating Group A Rotavirus in Gwangju Metropolitan City, Korea: 2008~2012

Group A rotaviruses are a major cause of acute gastroenteritis in young children worldwide. For the proper management of rotavirus infections, knowledge of the distribution of G and P genotypes including detection of emerging genotype is crucial. Therefore, the aim of this study is to describe epidemiological changes in rotavirus gastroenteritis in Gwangju metropolitan city, South Korea. Stool samples were collected from 14,314 patients with diarrhea, who visited hospitals in Gwangju from 2008 to 2012. Samples were screened for rotavirus with Enzyme-Linked Immunosorbent Assay (ELISA) method and rotavirus P (VP4), G (VP7) genotypes were determined by reverse-transcription polymerase chain reaction. And we performed nucleotide sequencing analysis. Among a total of 14,314 samples investigated 1,982 samples (13.8%) were ELISA positive. Genotyping of Rotavirus was performed using 526 rotavirus samples. The most prevalent circulating G genotype was G1 (40.5%), followed by G2 (27.6%), G3 (19.4%), G9 (9.7%), G4 (2.5%) and G12 (0.4%). The predominant type of P genotypes was P[8] (69.6%), followed by P[4] (27.8%) and P[6] (2.3%). In this study, 13 G-P combinations were detected. From 2008 to 2010, G1P[8] was the most prevalent, followed by G3P[8]. Whereas, 2011 and 2012, G2P[4] was the most common, followed by G1P[8]. Rotavirus gastroenteritis is a common disease associated with significant morbidity, mortality and economic burden. Ongoing rotavirus surveillance to understand the distribution of G and P genotypes will be critical for the development of effective prevention measurements.

Characterization of Community-Associated Methicillin-Resistant Staphylococcus aureus in Gwangju, Korea

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.

Visual Function Test for Early Detection of Ethambutol-Induced Ocular Toxicity

PURPOSE: The purpose of the present study was to investigate various visual function tests for early detection of ethambutol-induced ocular toxicity. METHODS: A prospective study of 20 eyes of 10 patients being treated with ethambutol was conducted. Visual acuity, visual field, color vision, fundus examination, contrast sensitivity, optical coherence tomography (OCT), and pattern-visual evoked potential (VEP) were assessed. Examinations were performed prior to therapy and every month for 5 months after treatment. VEP was performed every other month. The mean values of each parameter at each month were compared with the baseline examination and a p-value of <0.05 was considered significant. In addition, a greater than 2 standard deviation (SD) change in each parameter from the mean values at baseline was considered as an ocular toxicity induced change in each individual eye. RESULTS: On OCT, a significant increase of the average retinal nerve fiber layer thickness was detected after 4 months of therapy. VEP showed an increased mean latency of the P100 wave after 2 and 4 months of therapy. However, a greater than 2 SD change from the mean values of the baseline was not observed on OCT, while 30% (6/20) of the eyes showed more than a 2 SD increase in VEP latency. Visual acuity, color vision, fundus, contrast sensitivity, and visual field were not affected in any patients. CONCLUSIONS: The authors of the present study consider VEP as a sensitive test to detect early toxicity of ethambutol. VEP can be helpful in identifying subclinical ocular toxicity, especially in the high-risk patients.

Surveillance of Legionella Contamination on Water Supply Systems of Public Utilizing Facilities in Gwangju, Korea

Legionella is a pathogenic bacteria associated to aquatic habit of natural and artificial environments. Clinical cases of legionellosis have been reported in Korea but there is a lack of information about the incidence of this bacterium on environmental sources. Thus, we investigated the contamination of Legionella on water supply systems in Gwangju, Korea, including cooling towers, public baths, hospitals and fountains. Legionella spp. were detected from 81 samples (16.9%) out of 480 samples collected and the major species of Legionella isolates was identified to L. pneumophila serogroup (sg) 1 (n=33). The result of PFGE pattern analysis for L. pneumophila sg 1 isolates was discriminated into 11 pulsotypes. In dendrogram of PFGE, the clusters of isolates from cooling tower were quite different from those derived from hot water system of public bath. Surveillance for 4 sentinel public baths showed that their water supply systems had been contaminated with Legionella spp. and L. pneumophila sg 5 or sg 6 was the major isolate. The similarity of its PFGE patterns was 92.3%, 96.6%, respectively. Thus, PFGE may be a useful tool in molecular epidemiology studies, and the monitor and control for water supply systems of public utilizing facilities will be able to provide a resolution for the reduction of Legionella infection.

Surveillance of Legionella Contamination on Water Supply Systems of Public Utilizing Facilities in Gwangju, Korea

Legionella is a pathogenic bacteria associated to aquatic habit of natural and artificial environments. Clinical cases of legionellosis have been reported in Korea but there is a lack of information about the incidence of this bacterium on environmental sources. Thus, we investigated the contamination of Legionella on water supply systems in Gwangju, Korea, including cooling towers, public baths, hospitals and fountains. Legionella spp. were detected from 81 samples (16.9%) out of 480 samples collected and the major species of Legionella isolates was identified to L. pneumophila serogroup (sg) 1 (n=33). The result of PFGE pattern analysis for L. pneumophila sg 1 isolates was discriminated into 11 pulsotypes. In dendrogram of PFGE, the clusters of isolates from cooling tower were quite different from those derived from hot water system of public bath. Surveillance for 4 sentinel public baths showed that their water supply systems had been contaminated with Legionella spp. and L. pneumophila sg 5 or sg 6 was the major isolate. The similarity of its PFGE patterns was 92.3%, 96.6%, respectively. Thus, PFGE may be a useful tool in molecular epidemiology studies, and the monitor and control for water supply systems of public utilizing facilities will be able to provide a resolution for the reduction of Legionella infection.

The Distribution of Seropositivities for Human Immunodeficiency Virus and, Syphilis and the Gonorrhea Positive Rates in Gwangju (2002-2006)

BACKGROUND: The epidemic of human immunodeficiency virus (HIV) or sexually transmitted infections (STIs) is an important public health issue in the worldwide. Therefore, we investigated the trends of the seroprevalence of HIV and, syphilis and the gonorrhea positive rates in Gwangju from 2002 to 2006. MATERIALS AND METHODS: The results of laboratory tests for HIV, syphilis and gonorrhea were collected from five public health centers and 19 hospitals in Gwangju. The number of tested patients from 2002 to 2006 was 348,202 cases for HIV, 80,115 cases for syphilis and, 103,548 cases for gonorrhea. RESULTS: HIV/AIDS infections have rapidly increased at public health centers and hospitals. Especially, most of newly HIV-infected people were patients on ambulatory care/hospitalization, and they were also found via preoperation tests and according to the clinical symptoms. The gonorrhea positive rates have gradually decreased by year while the syphilis infection rates have slightly increased from 2002 to 2006. CONCLUSIONS: We have to determine the reasons why HIV and syphilis infections, but not gonorrhea, have increases simultaneously by the year. These results should be helpful to create a more effective STD prevention policy and the treatment guidelines for the people in Gwangju in the near future.

The Distribution of Seropositivities for Human Immunodeficiency Virus and, Syphilis and the Gonorrhea Positive Rates in Gwangju (2002-2006)

BACKGROUND: The epidemic of human immunodeficiency virus (HIV) or sexually transmitted infections (STIs) is an important public health issue in the worldwide. Therefore, we investigated the trends of the seroprevalence of HIV and, syphilis and the gonorrhea positive rates in Gwangju from 2002 to 2006. MATERIALS AND METHODS: The results of laboratory tests for HIV, syphilis and gonorrhea were collected from five public health centers and 19 hospitals in Gwangju. The number of tested patients from 2002 to 2006 was 348,202 cases for HIV, 80,115 cases for syphilis and, 103,548 cases for gonorrhea. RESULTS: HIV/AIDS infections have rapidly increased at public health centers and hospitals. Especially, most of newly HIV-infected people were patients on ambulatory care/hospitalization, and they were also found via preoperation tests and according to the clinical symptoms. The gonorrhea positive rates have gradually decreased by year while the syphilis infection rates have slightly increased from 2002 to 2006. CONCLUSIONS: We have to determine the reasons why HIV and syphilis infections, but not gonorrhea, have increases simultaneously by the year. These results should be helpful to create a more effective STD prevention policy and the treatment guidelines for the people in Gwangju in the near future.

Molecular Genetic Characterization of Shiga Toxin-producing E. coli Isolated from Diarrhea Patients and Cattle in Gwangju Area, Korea

Shiga toxin-producing Escherichia coli (STEC) can cause a broad spectrum of human illness ranging from symptom-free to hemolytic uremic syndrom (HUS). Associations between known or putative virulence factors of STEC and diseases in human were investigated. PCR analyses showed that 33 (78.6%) isolates carried an ehxA enterohemolysin gene and 6 (14.3%) isolates possessed an saa autoaggutinating adhesin gene, and 31 (73.8%) isolates carried an eae intimin gene (7 isolates with type beta, 16 with type gamma, and 3 with type epsilon). Twenty-nine (69%) isolates from patients carried eae+, ehxA+, saa- (genotype A) and 68 (86%) isolates from asymptomatic outbreaks and 4 (36%) isolates from bovine possessed eae-, ehxA+, saa+ (genotype C). Neither the bundle-forming pilus gene nor the enteropathogenic E. coli adherence factor plasmid was found. In HEp-2 cell adherence assay, isolates carrying eae gene exhibited a localized adherence phenotype, the other isolates carrying saa showed LC (loose clusters of bacteria) and IS (isolated bacteria). In conclusion, most STEC isolated from cattle feces in Gwangju, Korea showed characteristics different from those isolated from patients. But these results may be useful information for pathogenesis judgement of STEC.

Distribution of Group A Rotavirus Genotypes Circulating in Gwangju, Korea

To determine the distribution of rotavirus strain genotypes in Gwangju, Korea, we performed reverse-transcription polymerase chain reaction and nucleotide sequencing analysis using the 115 rotavirus EIA positive stool specimens collected from December 2006 through April 2007. The most predominant genotype was confirmed as G1P[8] (53.9%), followed by G3P[8] (29.6%), G4P[6] (8.7%), G2P[4] (4.3%) and G9P[8] (1.7%). A special attention is drawn to the unusual findings of the genotypes G11P[25] and G12P[9] during this study period. In order to investigate the phylogenetic relationships among the same or different genotypes, the nucleotide sequences of rotavirus circulating in Korea and the foreign countries were analyzed using MegAlign and Clustal X programme. The G11P[25] strain identified in this study showed the highest nucleic acid similarity with G11 /CUK1 /2006 /Korea (99.2%) and P[25] /Dhaka /2001 /BGD (98.7%). Meanwhile, the G12P[9] strain detected in this study shared 99.4~99.5% nucleotide homology with the reference strain G12P[9] /CP1030 /2004 /Japan. This incidence of new rotavirus genotypes in our area illustrates the large diversity of rotavirus strains found worldwide. Therefore, the epidemiological surveillance of rotavirus may need to be continued in a wide geographic area.

Identification of Shiga Toxin-producing E. coli Isolated from Diarrhea Patients and Cattle in Gwangju Area, Korea

Shiga toxin-producing Escherichia coli (STEC) strains are commensal bacteria in cattle and cause food borne disease in human. We analyzed the isolation rate of STEC in stool specimens of patients with diarrhea and in fecal samples of cattle in Gwangju, Korea. STEC strains were detected from 33 (0.19%) out of 17,148 patients with diarrhea while there has been a progressive increase in the incidence rate from 0.07% in 2004 to 0.33% in 2008. We investigated serotypes, shiga toxin genes, and antimicrobial resistance patterns of the 44 STEC isolates from human and cattle sources. The 33 STEC isolates from human belonged to 14 O serotypes including O157, O26 and O111. The 11 isolates from cattle belonged to 11 O serotypes. PCR detection for stx genes showed that 12 (27.3%) isolates carried stx1 genes, 20 (45.5%) possessed stx2 genes, and 12 (27.3%) carried both stx1 and stx2. Of the 33 STEC isolates from human, 25 strains (76%) were resistant to one or more antibiotics. High level of resistance to tetracycline (73%) was most common, followed by ticarcillin and ampicillin (64%). But none of the 33 isolates from human were resistant to amikacin, cefazolin, cefepime, cefotetan, cefotaxime, ciprofloxacin, or imipenem. The 5 strains (45%) of the 11 isolates from cattle were resistant to at least one or three antibiotics but most of the isolates were sensitive to the 16 antibiotics employed in this survey. In conclusion, toxin types and serotypes of STEC isolated from human and cattle were diverse, and non-O157 STEC was also observed to be a greater proportion of STEC isolates. According to a specific comparison solely based on the toxin types and serotypes, most of the STEC strains isolated from cattle feces in Gwangju, Korea showed characteristics different from those isolated from patients. Therefore, laboratory surveillance is required to detect and carefully monitor the potentially hypervirulent STEC not only in human and cattle but also in other animals.

Characterization of Respiratory Viral Infection in Children in Gwangju

BACKGROUND: This investigation was to perform the epidemiological surveillance and genetic analysis on respiratory viral agents from children with acute respiratory infections in Gwangju. MATERIALS AND METHODS: For this study, 3,695 specimens obtained from patients with acute respiratory infections were collected by collaboration with pediatric hospitals in Gwangju between 2005 and 2007. Specimens were screened for 8 respiratory viruses including influenza viruses (IFV), human rhinoviruses (HRV), human coronaviruses (HCoV), adenoviruses (ADV), parainfluenza viruses (PIV), human enteroviruses (HEV), respiratory synthitial viruses (RSV) and human bocaviruses (HBoV). Respiratory viruses were detected using multiplex (RT) PCR with viral specific primers. RESULTS: Out of 3,695 specimens, the ratio of virus detection was 24.9% (919). Overall, HRV (35.5%) and IFV (34.9%) were the most common viruses found, followed by HBoV (14.8%), HCoV (10.6%), RSV (3.7%), ADV (3.4%), PIV (3.2%) and HEV (3.0%). In addition, multiple infections were detected in 80 patients (8.7%). When the prevalence was analyzed according to season, HBoV, IFV and HCoV showed two epidemic points in late spring and early winter. ADV, HRV, RSV PIV and HEV, however, were all found to have only one epidemic point, with RSV being most common during winter and the others being most prominent during spring. CONCLUSIONS: Through this epidemiological surveillance, the respiratory viruses prevalent in children in Gwangju area were investigated. We strongly recommend the development of nationwide policy for the management of prevalent respiratory virus that includes long term collection of data and samples, vaccine development and prevention education of the misuse of antibiotics.

Characterization of Respiratory Viral Infection in Children in Gwangju

BACKGROUND: This investigation was to perform the epidemiological surveillance and genetic analysis on respiratory viral agents from children with acute respiratory infections in Gwangju. MATERIALS AND METHODS: For this study, 3,695 specimens obtained from patients with acute respiratory infections were collected by collaboration with pediatric hospitals in Gwangju between 2005 and 2007. Specimens were screened for 8 respiratory viruses including influenza viruses (IFV), human rhinoviruses (HRV), human coronaviruses (HCoV), adenoviruses (ADV), parainfluenza viruses (PIV), human enteroviruses (HEV), respiratory synthitial viruses (RSV) and human bocaviruses (HBoV). Respiratory viruses were detected using multiplex (RT) PCR with viral specific primers. RESULTS: Out of 3,695 specimens, the ratio of virus detection was 24.9% (919). Overall, HRV (35.5%) and IFV (34.9%) were the most common viruses found, followed by HBoV (14.8%), HCoV (10.6%), RSV (3.7%), ADV (3.4%), PIV (3.2%) and HEV (3.0%). In addition, multiple infections were detected in 80 patients (8.7%). When the prevalence was analyzed according to season, HBoV, IFV and HCoV showed two epidemic points in late spring and early winter. ADV, HRV, RSV PIV and HEV, however, were all found to have only one epidemic point, with RSV being most common during winter and the others being most prominent during spring. CONCLUSIONS: Through this epidemiological surveillance, the respiratory viruses prevalent in children in Gwangju area were investigated. We strongly recommend the development of nationwide policy for the management of prevalent respiratory virus that includes long term collection of data and samples, vaccine development and prevention education of the misuse of antibiotics.

Genotypic and Phenotypic Characterization of Enteropathogenic Escherichia coli Isolated from Diarrheal Patients in Gwangju

Enteropathogenic Escherichia coli (EPEC) have been implicated in human diarrhea in several countries. Central to EPEC-mediated disease is its ability to cause intestinal lesions, known as attaching and effacing (A/E) lesion. We investigated 92 EPEC strains isolated from patients with diarrhea in Gwangju for their genotypic and phenotypic characteristics. Sixteen (17.4%) of all strains were found to be typical EPEC because they were bfpA gene positive by PCR. The most of typical EPEC isolates (87.5%) showed a localized adhesion (LA) pattern in Hep-2 cell adherence assay, whereas, only 11 atypical EPEC isolates (14.5%) were adhered to Hep-2 cells in a localized manner. Thirteen of the EPEC strains studied belonged to classical O-serogroups of EPEC and 7 isolates were classified as nonclassical EPEC serogroup and the other isolates could not be serotyped with our antisera. The subtypes of eae, tir, espA and espB genes which are major virulence genes concerned of A/E lesion on chromosome were analyzed by multiplex PCR for finding the original resource. The results showed that the composition of these genes subtypes was homogenous and heterogenous in 12 and 26 isolates, respectively. The others were non-determined type in terms of the gene subtype because of genetic diversity of intimin-coding eae genes. Our findings indicated that EPEC isolates from patients with diarrhea were diverse genetically and phenotypically, which require further study in regard to their virulence and epidemiological significance.