Epidemiology and Investigation of Foot‐and‐Mouth Disease (FMD) in the Republic of Korea

This chapter describes about the experience of dealing with FMD outbreaks in the Republic of Korea. We explain what is FMD, the concept of epidemiological investigation on outbreak sites of FMD, including the episode of detecting the index case for seven epidemics occurred since 2000, and information obtained from investigation in Korea. In any case, farmers’ attitude (recognize clinical signs and report suspected cases) played the essential role in determining size and duration of epidemics. A rapid and correct diagnosis including clinical examination and laboratory test for confirmation is also important

Antiretroviral Genotypic Resistance Mutations in HIV-1 Infected Korean Patients with Virologic Failure

Resistance assays are useful in guiding decisions for patients experiencing virologic failure (VF) during highly-active antiretroviral therapy (HAART). We investigated antiretroviral resistance mutations in 41 Korean human immunodeficiency virus type 1 (HIV-1) infected patients with VF and observed immunologic/virologic response 6 months after HAART regimen change. Mean HAART duration prior to resistance assay was 45.3±27.5 months and commonly prescribed HAART regimens were zidovudine/lamivudine/nelfinavir (22.0%) and zidovudine/lamivudine/efavirenz (19.5%). Forty patients (97.6%) revealed intermediate to high-level resistance to equal or more than 2 antiretroviral drugs among prescribed HAART regimen. M184V/I mutation was observed in 36 patients (87.7%) followed by T215Y/F (41.5%) and M46I/L (34%). Six months after resistance assay and HAART regimen change, median CD4+ T cell count increased from 168 cells/µL (interquartile range [IQR], 62-253) to 276 cells/µL (IQR, 153-381) and log viral load decreased from 4.65 copies/mL (IQR, 4.18-5.00) to 1.91 copies/mL (IQR, 1.10-3.60) (P<0.001 for both values). The number of patients who accomplished viral load <400 copies/mL was 26 (63.4%) at 6 months follow-up. In conclusion, many Korean HIV-1 infected patients with VF are harboring strains with multiple resistance mutations and immunologic/virologic parameters are improved significantly after genotypic resistance assay and HAART regimen change

Genome-Based Construction of the Metabolic Pathways of Orientia tsutsugamushi and Comparative Analysis within the Rickettsiales Order

Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium that belongs to the order of Rickettsiales. Recently, we have reported that O. tsutsugamushi has a unique genomic structure, consisting of highly repetitive sequences, and suggested that it may provide valuable insight into the evolution of intracellular bacteria. Here, we have used genomic information to construct the major metabolic pathways of O. tsutsugamushi and performed a comparative analysis of the metabolic genes and pathways of O. tsutsugamushi with other members of the Rickettsiales order. While O. tsutsugamushi has the largest genome among the members of this order, mainly due to the presence of repeated sequences, its metabolic pathways have been highly streamlined. Overall, the metabolic pathways of O. tsutsugamushi were similar to Rickettsia but there were notable differences in several pathways including carbohydrate metabolism, the TCA cycle, and the synthesis of cell wall components as well as in the transport systems. Our results will provide a useful guide to the postgenomic analysis of O. tsutsugamushi and lead to a better understanding of the virulence and physiology of this intracellular pathogen

THE GEOMETRY OF STEAM GENERATOR TUBE AND ITS RELEVANCE TO THE OCCURRENCE OF STRESS CORROSION CRACKING IN OPERATING NUCLEAR POWER PLANTS

INTRODUCTION Occurrences of a stress corrosion cracking in the steam generator tubes of operating nuclear power plants are closely related to the residual stress existing in the local region of a geometric change, that is, expansion transition, u-bend, ding, dent, bulge, etc. Therefore, information on the location, type and quantitative size of a geometric anomaly existing in a tube is a prerequisite to the activity of a non destructive inspection for an alert detection of an earlier crack and the prediction of a further crack evolution In order to verify the performance of the D-probe including the accuracy of the profile measurement and a applicability of the probe to the plant inspection, the quantitatively measured profile data are compared with those from the laser profilometry (measurement resolution of 0.013mm) for the steam generator tube samples of geometric anomalies with various types and sizes, and the relationship between the tube geometry and the evolution of ID and OD side stress corrosion cracking at various tube locations of a steam generator is discussed with the results from the inservice inspections of operating nuclear power plants using a D-probe

Factors Associated with HIV-1 Proviral DNA Loads in Patients with Undetectable Plasma RNA Load

To evaluate factors associated with human immunodeficiency virus type 1 (HIV-1) proviral DNA load, we conducted a cross-sectional study of 36 chronically HIV-1-infected individuals with undetectable plasma viral RNA. We used real-time polymerase chain reaction to determine the number of HIV-1 proviral DNA copies per 106 peripheral blood mononuclear cells. The mean level of plasma viral RNA when the CD4+ T cell count was above 500 cells/µL without highly active antiretroviral therapy (HAART) was significantly associated with proviral DNA load at the time of undetectable plasma HIV RNA with HAART. Strategies to reduce the level of plasma viral RNA when patients' CD4+ T cell counts are above 500 cells/µL without HAART could help reduce HIV-1 proviral DNA load

The Characteristics of Metallo-β-Lactamase-Producing Gram-Negative Bacilli Isolated from Sputum and Urine: A Single Center Experience in Korea

Metallo-β-lactamase (MBL) production usually results in high-level resistance to most β-lactams, and a rapid spread of MBL producing major gram-negative pathogens is a matter of particular concern worldwide. However, clinical data are scarce and most studies compared MBL producer (MP) with MBL non-producer (MNP) strains which included carbapenem susceptible isolates. Therefore, we collected clinical data of patients in whom imipenem-nonsusceptible Pseudomonas aeruginosa (PA) and Acinetobacter baumannii (AB) were isolated from sputum or urine, and investigated MBL production and the risk factors related with MBL acquisition. The antimicrobial susceptibility patterns were also compared between MPs and imipenem-nonsusceptible MNPs (INMNP). Among the 176 imipenem-nonsusceptible isolates, 12 MPs (6.8%) were identified. There was no identifiable risk factor that contributed to the acquisition of MPs when compared to INMNPs, and case-fatalities were not different between the two groups. The percentage of susceptible isolates was higher among MPs for piperacilin/tazobactam and fluoroquinolones while that of ceftazidime was higher in INMNPs (p < 0.05). As regards to aztreonam, which has been known to be a uniquely stable β-lactam against MBLs, susceptibility was preserved in only two isolates (16.7%) among MPs, and was not higher than that of INMNPs (23.2%). In conclusion, the contribution of MBLs to imipenem non-susceptibility in PA/ABs isolated from sputum and urine was relatively limited, and there was no significant risk factor associated with acquisition of MPs compared with INMNPs. However, limited susceptibility to aztreonam implies that MPs may hold additional resistance mechanisms, such as extended spectrum β-lactamases, AmpC β-lactamases, or other non-enzymatic mechanisms

Orientia tsutsugamushi and Comparative Analysis within the Rickettsiales Order

Orientia tsutsugamushi, the causative agent of scrub typhus, is an obligate intracellular bacterium that belongs to the order of Rickettsiales. Recently, we have reported that O. tsutsugamushi has a unique genomic structure, consisting of highly repetitive sequences, and suggested that it may provide valuable insight into the evolution of intracellular bacteria. Here, we have used genomic information to construct the major metabolic pathways of O. tsutsugamushi and performed a comparative analysis of the metabolic genes and pathways of O. tsutsugamushi with other members of the Rickettsiales order. While O. tsutsugamushi has the largest genome among the members of this order, mainly due to the presence of repeated sequences, its metabolic pathways have been highly streamlined. Overall, the metabolic pathways of O. tsutsugamushi were similar to Rickettsia but there were notable differences in several pathways including carbohydrate metabolism, the TCA cycle, and the synthesis of cell wall components as well as in the transport systems. Our results will provide a useful guide to the postgenomic analysis of O. tsutsugamushi and lead to a better understanding of the virulence and physiology of this intracellular pathogen

Clinical Review of Endogenous Endophthalmitis in Korea: A 14-Year Review of Culture Positive Cases of Two Large Hospitals

PURPOSE: To identify the clinical features and outcomes of endogenous endophthalmitis in Korea. MATERIALS AND METHODS: We reviewed 18 patients with endogenous endophthalmitis at 2 Korean hospitals, treated over a 14 year period between January 1993 and December 2006. RESULTS: The comorbidities observed in these cases were diabetes mellitus and liver cirrhosis. The most common pathogens, which were found in 7 patients each (38.9%), were Klebsiella pneumonia and Pseudomonas aeruginosa. All patients were treated with systemic antibiotics and fortified topical antibiotics. A surgical approach including vitrectomy was performed in 9 cases (50.0%). The prognosis was generally poor, and visual acuity improved slightly in 6 patients (33.3%). CONCLUSION: In this study, diabetes mellitus and Klebsiella pneumonia showed a close relationship with endogenous endophthalmitis, respectively. Endogenous endophthalmitis is a serious risk to sight and careful attention to establishing the diagnosis and management may decrease the ocular morbidity.ope

Peritonsillar Abscess in a 40-Day-Old Infant

A peritonsillar abscess is one of the most commonly occurring deep space infections of the head and neck in adults and children. A peritonsillar abscess that appears in newborns, however, is extremely rare. The treatment of a peritonsillar abscess requires both the selection of appropriate antibiotics and the best procedure to remove the abscessed material. We report a case of a peritonsillar abscess in a 40-day-old infant who was treated with antibiotic therapy alone

Epidemiologic survey of head and neck cancers in Korea.

Head and neck cancers have never been systematically studied for clinical purposes yet in Korea. This epidemiological survey on head and neck cancer patients was undertaken from January to December 2001 in 79 otorhinolaryngology resident-training hospitals nationwide. The number of head and neck cancer patients was 1,063 cases in the year. The largest proportion of cases arose in the larynx, as many as 488 cases, which accounted for 45.9%. It was followed by, in order of frequency, oral cavity (16.5%), oropharynx (10.0%), and hypopharynx (9.5%). The male:female ratio was 5:1, and the mean age was 60.3 yr. Surgery was the predominant treatment modality in head and neck cancers: 204 (21.5%) cases were treated with only surgery, 198 (20.8%) cases were treated with surgery and radiotherapy, 207 cases (21.8%) were treated with combined therapy of surgery, radiotherapy, and chemotherapy. Larynx and hypopharynx cancers had a stronger relationship with smoking and alcohol drinking than other primary site cancers. Of them, 21 cases were found to be metastasized at the time of diagnosis into the lung, gastrointestinal tract, bone, or brain. Coexisting second primary malignancies were found in 23 cases. At the time of diagnosis, a total of 354 cases had cervical lymph node metastasis accounting for 42.0%