Nationwide Survey for Current Status of Laboratory Diagnosis of Clostridioides difficile Infection in Korea

Background@#The interest in Clostridioides difficile infection (CDI) has increased, and the choice of assays became wider since the first national survey in Korea on CDI diagnosis in 2015. We conducted a survey of the domestic CDI assays with more varied questions to understand the current situation in Korea. @*Methods@#In April 2018, about 50 questions on the current status of CDI assays and details on implementation and perceptions were written, and a survey questionnaire was administered to laboratory medicine specialists in 200 institutions. @*Results@#One-hundred and fifty institutions responded to the questionnaire, of which 90 (60.0%) including one commercial laboratory, performed CDI assays. The toxin AB enzyme immunoassay (toxin AB EIA), nucleic acid amplification test (NAAT), and C. difficile culture, glutamate dehydrogenase assay, alone or in combination with other assays, were used in 75 (84.3%), 52 (58.4%), 35 (36.0%), and 23 (25.8%), respectively, and 65 (73.0%) institutions performed a combination of two or more assays. The sensitivity of toxin AB EIA was more negatively perceived, and that on specificity was more positively perceived. The perception of sensitivity and specificity of NAAT was mostly positive. Perception on the algorithm test projected it as useful but in need of countermeasures. Sixty-three (73.3%) institutions responded that they performed surveillance on CDI. @*Conclusion@#This study provides useful evidence on the current status of CDI laboratory diagnosis in Korea as well as on items that require improvement and is thought to aid in standardizing and improving the CDI laboratory diagnosis in Korea.

Comparison of the Seroprevalence of Measles Antibodies among Healthcare Workers in Two Korean Hospitals in 2019

We performed a point seroprevalence survey of measles among healthcare workers (HCWs) at two Korean teaching hospitals in 2019. A total of 2,830 HCWs underwent an antibody test.The overall seropositivity of measles was 93.1%. The seroprevalence of measles was lowest in HCWs aged 20 - 24 years (81.2%), followed by those aged 25 - 29 years (90.1%). The rates of anti-measles IgG positivity were significantly different between the two hospitals (97.0% vs.89.4%, P <0.001). These results suggest that the seropositivity of measles in HCWs may differ depending on the hospital's vaccination policy.

Outbreak of Swine-Origin Influenza A (H1N1); Experience of a Regional Center in Seoul during a Month, August-September 2009 / 대한임상미생물학회지

BACKGROUND: The aim of this study is to clarify the epidemiology of swine-origin influenza A (H1N1) virus 2009 (S-OIV) during the first month of outbreak at one of influenza clinic in Seoul, Korea. METHODS: We documented the epidemiologic and clinical features of S-OIV-confirmed cases who visited a university hospital in Northeastern Seoul between August 21 and September 20, 2009. Nasopharyngeal swab of patients with acute febrile respiratory illnesses were evaluated with rapid influenza antigen tests and multiplex RT-PCR for S-OIV and seasonal influenza A. RESULTS: A total of 5,322 patients with acute febrile respiratory illnesses were identified at our influenza clinic for the study period. S-OIV was confirmed in 309 patients by RT-PCR. The patients ranged from 2 months to 61 years of age and 189 patients (61.2%) were teenagers. Eighty-one patients had known contact with S-OIV-confirmed patients in schools (N=61), households (N=15), and healthcare facilities (N=3). Frequent symptoms were fever (94.5%), cough (73.1%), sore throat (52.1%), and rhinorrhea (50.5%). Gastrointestinal symptoms were also present in 10 patients (4.9%). Ten patients (4.9%) required hospitalizations. Seventy patients (22.7%) could not take oseltamivir at the first visits, however, all of them recovered without complication. Rapid antigen tests showed the sensitivity of 44.4% (130/294). Patients with positive antigen tests, compared with negative antigen tests, showed higher frequencies of rhinorrhea (60.8% vs 43.3%, P=0.004) and stuffy nose (33.8% vs 20.1%, P=0.012). CONCLUSION: S-OIV infections spread predominately in school-aged children during the early accelerating phase of the outbreak. Rapid influenza antigen tests were correlated with nasal discharge and obstruction.

Chemokine Lkn-1/CCL15 enhances matrix metalloproteinase-9 release from human macrophages and macrophage-derived foam cells

Atherosclerosis is characterized by a chronic inflammatory disease, and chemokines play an important role in both initiation and progression of atherosclerosis development. Leukotactin-1 (Lkn-1/CCL15), a new member of the human CC chemokine family, is a potent chemoattractant for leukocytes. Our previous study has demonstrated that Lkn-1/CCL15 plays a role in the initiation of atherosclerosis, however, little is currently known whether Lkn-1/CCL15 is associated with the progression of atherosclerosis. Matrix metalloproteinases (MMPs) in human coronary atherosclerotic lesions play a crucial role in the progression of atherosclerosis by altering the vulnerability of plaque rupture. In the present study, we examined whether Lkn-1/CCL15 modulates MMP-9 release, which is a prevalent form expressed by activated macrophages and foam cells. Human THP-1 monocytic cells and/or human peripheral blood monocytes (PBMC) were treated with phorbol myristate acetate to induce their differentiation into macrophages. Foam cells were prepared by the treatment of THP-1 macrophages with human oxidized LDL. The macrophages and foam cells were treated with Lkn-1/CCL15, and the levels of MMP-9 release were measured by Gelatin Zymography. Lkn-1/CCL15 significantly enhanced the levels of MMP-9 protein secretion from THP-1 monocytic cells-derived macrophages, human PBMC-derived macrophages, as well as macrophage-derived foam cell in a dose dependent manner. Our data suggest that the action of Lkn-1/CCL15 on macrophages and foam cells to release MMP-9 may contribute to plaque destabilization in the progression of atherosclerosis.

Coil Embolization of Spontaneous Vertebral Arteriovenous Fistula Associated with Neurofibromatosis Type 1: A Case Report / 신경중재치료의학

We present a case of 44-year-old male with spontaneous right vertebral arteriovenous fistula associated with neurofibromatosis type 1. The symptom of this patient was myeloradiculopathy of which was due to compressed cervical spinal cord by enlarged epidural vein. Complete occlusion of the fistula using coils resulted in relief of the patient symptom and complete disappearance of enlarged epidural vein on follow-up MR image one month later.

Seroprevalence of Hepatitis B Virus among Health Care Workers in Korea

We studied the seroprevalence of HBsAg, anti-HBs and anti-HBc and the vaccination histories among health care workers (HCWs) at a large suburban referral hospital in Korea. The purpose of this study was to determine the immune status of HCWs against hepatitis B virus and we also wanted to prepare a practical guideline to protect HCWs from occupational exposure. During December, 2003, 571 HCWs (56 physicians, 289 nurses, 113 technicians and 113 aid-nurses) aged between 21 and 74 yr were included in the surveillance. The positive rates of HBsAg and anti-HBs were 2.4% (14/571) and 76.9% (439/571), respectively. The positive rate of anti-HBs was lower in the physician group, and this was associated with the male gender and older age. Of the 439 anti-HBs positive cases, 320 cases (73.1%) were anti-HBc negative and this was significantly associated with a past history of HBV vaccination. The distribution of the anti-HBs levels was not associated with age (except for HCWs in their sixties), gender or occupation. Our study revealed that the seroprevalence rates of HBsAg and anti-HBs in HCWs in Korea were not different from those of the general population. Based on this surveillance, we can make reasonable decisions in case of occupational exposure to hepatitis B virus.

Usefulness of Helical CT for the Preoperative Evaluation of Small Advanced Gastric Cancer Mimicking as Early Gastric Cancer at Endoscopy

PURPOSE: We wanted to evaluate the usefulness of helical CT, along with histopathologic correlation, for the preoperative evaluation of small advanced gastric cancers (AGCs) mimicking as early gastric cancer (EGCs) at endoscopy. MATERIALS AND METHODS: From February 2001 to September 2004, we retrospectively reviewed 17 patients with pathologically proven small AGCs that were misinterpreted as EGCs at endoscopy. The preoperative helical CT findings were prospectively analyzed and the CT staging was compared with the pathologic staging that was based on the depth of tumor invasion and status of lymph node metastasis, according to the TNM classification. RESULTS: The endoscopic findings of the 17 AGCs misinterpreted as EGCs were type IIc (n=7), IIb+IIc (n=3), IIa+IIc (n=3), IIa+IIb (n=1), and III (n=3). The mean size of the AGCs on the gross specimen was 2.8 cm (range: 1.2 cm-5 cm). Helical CT clearly depicted the depth of tumor invasion by the marked transmural enhancement or the reticular strands in the exraserosal fat. Preoperative helical CT detected all 17 AGCs (100%) and it correctly diagnosed then as AGCs in 15 (88%) of 17 cases. CT staging for the T category correctly staged 12 cases (71%), it understaged four cases and it overstaged one case. Regional lymph node metastasis was positive in 11 (64%) of 17 cases on the pathologic examination. The CT staging for the N category correctly staged 10 (59%) of 17 cases, it understaged four cases, and it overstaged three cases. CONCLUSION: Preoperative helical CT correctly diagnosed small AGCs mimicking as EGCs at endoscopy. Our results show that helical CT can be useful for the decision-making during the treatment planning for those patients with gastric cancer in which the endoscopic distinction between EGC and AGC is difficult.