Surveillance of Coronavirus Disease 2019 (COVID-19) Testing in Clinical Laboratories in Korea

In response to the ongoing coronavirus disease 2019 (COVID-19) pandemic, an online laboratory surveillance system was established to monitor severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) real-time reverse transcription-PCR (rRT-PCR) testing capacities and results. SARS-CoV-2 rRT-PCR testing data were collected from 97 clinical laboratories, including 84 medical institutions and 13 independent clinical laboratories in Korea. We assessed the testing capacities to utilize SARS-CoV-2 rRT-PCR based on surveillance data obtained from February 7th to June 4th, 2020 and evaluated positive result characteristics according to the reagents used and sample types. A total of 1,890,319 SARS-CoV-2 rRT-PCR testing were performed, 2.3% of which were positive. Strong correlations were observed between the envelope (E ) gene and RNA-dependent RNA polymerase (RdRp )ucleocapsid (N ) genes threshold cycle (Ct) values for each reagent. No statistically significant differences in gene Ct values were observed between the paired upper and lower respiratory tract samples, except in the N gene for nasopharyngeal swab and sputum samples. Our study showed that clinical laboratories in Korea have rapidly expanded their testing capacities in response to the COVID-19 outbreak, with a peak daily capacity of 34,193 tests. Rapid expansion in testing capacity is a critical component of the national response to the ongoing pandemic.

Guidelines for Laboratory Diagnosis of Coronavirus Disease 2019 (COVID-19) in Korea

The outbreak of coronavirus disease 2019 (COVID-19), which began in December 2019, is still ongoing in Korea, with >9,000 confirmed cases as of March 25, 2020. COVID-19 is a severe acute respiratory syndrome Coronavirus 2 (SARS-CoV-2) infection, and real-time reverse transcription-PCR is currently the most reliable diagnostic method for COVID-19 around the world. Korean Society for Laboratory Medicine and the Korea Centers for Disease Prevention and Control propose guidelines for diagnosing COVID-19 in clinical laboratories in Korea. These guidelines are based on other related domestic and international guidelines, as well as expert opinions and include the selection of test subjects, selection of specimens, diagnostic methods, interpretation of test results, and biosafety.

Multiple Human Papillomavirus Infection Is Associated with High-Risk Infection in Male Genital Warts in Ulsan, Korea

Further understanding of male human papillomavirus (HPV) infection is necessary to prevent infection in men, as well as transmission to women. In our current study, we investigated patterns of HPV infection and genotype distributions in male genital warts using the Anyplex II HPV28 Detection kit. We reviewed the medical records of 80 male patients who presented to 5 neighborhood clinics in Ulsan, Korea, for the treatment of genital warts between April 2014 and January 2015. All patients underwent HPV genotyping. The prevalence and characteristics of HPV infection were analyzed, and the patterns of HPV infection according to age were assessed. Among the study patients, 13 (16.3%) were negative for HPV infection, 46 (57.3%) were infected with low-risk HPV, and 21 (26.3%) were infected with high-risk HPV. Patients with multiple HPV infection were more likely to have high-risk HPV infection (P = 0.001). The prevalence of HPV infection was much higher in samples obtained by tissue excision due to a definite lesion (P = 0.001). There were no differences in high-risk HPV infection (P = 0.459), multiple HPV infection (P = 0.185), and recurrence at diagnosis (P = 0.178) according to age. HPV-6 and HPV-11 were the most common type overall (39.7% and 13.8%, respectively). HPV-16 and HPV-18 were the most common high-risk infections (both 3.4%). HPV infection is not only commonly encountered in male genital warts, but is also accompanied by high-risk HPV and multiple infections.

Relationship between the Severity of Diversion Colitis and the Composition of Colonic Bacteria: A Prospective Study

BACKGROUND/AIMS: Diversion colitis is the inflammation of the excluded segment of the colon in patients undergoing ostomy. It has been suggested that a change in colonic flora may lead to colitis; however, direct evidence for this disease progression is lacking. The aim of this study was to evaluate the relationship between the severity of diversion colitis and the composition of colonic bacteria. METHODS: We used culture methods and polymerase chain reaction to analyze the colonic microflora of patients who underwent rectal cancer resection with or without diversion ileostomy. In the diversion group, we also evaluated the severity of colonoscopic and pathologic colitis before reversal. RESULTS: This study enrolled 48 patients: 26 in the diversion group and 22 in the control group. Significant differences were observed between the two groups in the levels of Staphylococcus (p=0.038), Enterococcus (p<0.001), Klebsiella (p<0.001), Pseudomonas (p=0.015), Lactobacillus (p=0.038), presence of anaerobes (p=0.019), and Bifidobacterium (p<0.001). A significant correlation between the severity of colitis and bacterial composition was only observed for Bifidobacterium (p=0.005, correlation coefficient=-0.531). CONCLUSIONS: The colonic microflora differed significantly between the diversion and control groups. Bifidobacterium was negatively correlated with the severity of diversion colitis.

Nasal Colonization and Molecular Characterization of Methicillin-Resistant Staphylococcus aureus among Hemodialysis Patients in 7 Korean Hospitals / 병원감염관리

BACKGROUND: Staphylococcus aureus is a major bacteremia-causing pathogen in hemodialysis patients, frequently colonizing patient skin and mucosa. Active infection control is necessary to prevent methicillin-resistant S. aureus (MRSA) infection in hospitals; however, the spread of community-associated MRSA has recently become a concern for MRSA infection control. We evaluated the nasal colonization of MRSA among hemodialysis patients and the molecular characterization of the MRSA isolates. METHODS: Nasal swabs were obtained from 482 hemodialysis patients in 7 nationwide hospitals in November 2009, and cultured for MRSA colonization. Swabs were inoculated and cultured in 6.5% NaCl tryptic soy broth, then subcultured on MRSASelect medium (Bio-Rad, Hercules, CA) for 20-24 h. Multiplex PCR was performed to analyze staphylococcal cassette chromosome mec (SCCmec) types of MRSA isolates. RESULTS: Of 482 hemodialysis patients, 57 (11.8%) carried MRSA, ranging from 6.7% to 19.0%. Among the 57 MRSA isolates, we identified 3 (5.3%) SCCmec II, 1 (1.8%) SCCmec IIA, 30 (52.6%) SCCmec IIB, 1 (1.8%) SCCmec III, 6 (10.5%) SCCmec IV, and 16 (28.1%) SCCmec IVA subtypes. CONCLUSION: The MRSA carriage rate (11.8%) of hemodialysis patients in this study was high. The SCCmec IIB subtype, a healthcare-associated strain, was the predominant strain, although SCCmec IV isolates, typically found in community-associated MRSA infections, were also frequently observed. To prevent healthcare-associated MRSA infections in hemodialysis patients, standardized infection control measures should be performed, and efforts to reduce MRSA carriage rates should be considered.

Epidemiologic Features of Parainfluenza Virus Type 1, 2 and 3 Infection in Seoul and a Neighboring Area, 2008-2011 / 대한임상미생물학회지

BACKGROUND: Parainfluenza virus (PIV) is a significant cause of acute respiratory infections. Epidemiological information on PIV infection could be very helpful for patient management. The aim of this study was to investigate the epidemiology of PIV infection in Seoul and a neighboring area with regard to PIV type. METHODS: The diagnosis of PIV infection was made by virus isolation. The R-mix Too cell system (Diagnostic Hybrids, Inc., Athens, OH, USA) and D3 Ultra DFA Respiratory Virus Screening & ID kits (Diagnostic Hybrids, Inc.) were used for virus culture and identification. The medical records of patients with positive virus cultures were reviewed retrospectively. RESULTS: Seven hundred and ten PIV viruses (5.6%) were isolated from 12,723 specimens. The number of subjects with PIV type III, I and II was 357, 304 and 49, respectively. PIV infection showed a peak incidence in the first year of life regardless of subtypes. The most common diagnosis among all PIV subtypes was pneumonia. Lower respiratory tract infections constituted the majority (76.3%) of PIV infections. The most common diagnosis of PIV type I and II was croup and that of PIV type III was pneumonia. A difference in seasonal variation between subtypes was observed. PIV I (62.2%) was mainly isolated from July to September while PIV type III (86.8%) was isolated from April to July. CONCLUSION: Lower respiratory infection was most commonly found in hospitalized patients with PIV infection. Clinical features of PIV infection were similar those seen in Western PIV reports, with the exception of the seasonal outbreak pattern.

Isolation of a Klebsiella pneumoniae Isolate of Sequence Type 258 Producing KPC-2 Carbapenemase in Korea / 대한진단검사의학회지

Carbapenem-resistant Klebsiella pneumoniae isolates producing K. pneumoniae carbapenemases (KPC) were first reported in the USA in 2001, and since then, this infection has been reported in Europe, Israel, South America, and China. In Korea, the first KPC-2-producing K. pneumoniae sequence type (ST) 11 strain was detected in 2010. We report the case of a patient with a urinary tract infection caused by KPC-2-producing K. pneumoniae. This is the second report of a KPC-2-producing K. pneumoniae infection in Korea, but the multilocus sequence type was ST258. The KPC-2-producing isolate was resistant to all tested beta-lactams (including imipenem and meropenem), amikacin, tobramycin, ciprofloxacin, levofloxacin, and trimethoprim-sulfamethoxazole, but was susceptible to gentamicin, colistin, polymyxin B, and tigecycline. The KPC-2-producing isolate was negative to phenotypic extended-spectrum beta-lactamase (ESBL) and AmpC detection tests and positive to modified Hodge test and carbapenemase inhibition test with aminophenylboronic acid.

Clinical Characteristics and Comparison of the Various Methods Used for the Diagnosis of the New Influenza A Pandemic in Korea

BACKGROUND: Laboratory diagnosis of new influenza A (H1N1) is crucial for managing patients and establishing control and prevention measures. We compared the diagnostic accuracies of the real time RT-PCR (rRT-PCR) test recommended for the confirmation of the new flu and the viral culture method used conventionally for viral disease with that of the rapid antigen test (RAT). METHODS: We performed RAT, R-mix culture, and real-time PCR by using 861 respiratory samples collected from December 2009 to January 2010 and evaluated the abilities of these methods to detect new influenza A. The relationship among the positive rates of RAT, grades of culture, and the cycle threshold (Ct) values of rRT-PCR was also evaluated. RESULTS: Of the 861 patients, 308 (35.8%) were diagnosed with new influenza A. The sensitivities, specificities, positive predictive values, and negative predictive values of the tests were respectively as follows: 59.7%, 99.5%, 98.4%, and 81.6% for RAT; 93.2%, 100%, 100%, and 96.3% for R-mix culture; and 95.8%, 100%, 100%, and 97.7% for rRT-PCR. Samples with weak positive grade in culture and those with Ct values of 30-37 in rRT-PCR showed positivities as low as 25.3% and 2.3% in RAT, respectively. The hospitalization rate and death rate of the confirmed patients were 3.2% and 0.3%, respectively, and gastrointestinal symptoms were observed in 7.2% of the patients. CONCLUSIONS: R-mix culture and rRT-PCR tests showed excellent reliability in the diagnosis of new influenza A and could be very useful, especially for samples with low viral load.

Rapid Identification of Thrombocytopenia-Associated Multiple Organ Failure Using Red Blood Cell Parameters and a Volume/Hemoglobin Concentration Cytogram

Thrombocytopenia-associated multiple organ failure (TAMOF) has a high mortality rate when not treated, and early detection of TAMOF is very important diagnostically and therapeutically. We describe herein our experience of early detection of TAMOF, using an automated hematology analyzer. From 498,390 inpatients, we selected 12 patients suspected of having peripheral schistocytosis, based on the results of red blood cell (RBC) parameters and a volume/hemoglobin concentration (V/HC) cytogram. We promptly evaluated whether the individual patients had clinical manifestations and laboratory findings were consistent with TAMOF. Plasma exchanges were then performed for each patient. All 12 patients had TAMOF. The mean values of RBC parameters were significantly higher in all of the patients than with the reference range, however, 3 patients had % RBC fragments within the reference range. The mean value of ADAMTS-13 activity was slightly lower in patients compared with the reference range. Of the 12 patients, remission was obtained in 9 patients (75%) within 4 to 5 weeks using plasma exchanges. Three patients died. An increased percentage of microcytic hyperchromic cells with anisocytosis and anisochromia indicated the presence of schistocytes, making it an excellent screening marker for TAMOF. Identification of TAMOF with RBC parameters and a V/HC cytogram is a facile and rapid method along with an automated hematology analyzer already in use for routine complete blood cell counting test.

CD4+/CD8+ T lymphocytes imbalance in children with severe 2009 pandemic influenza A (H1N1) pneumonia / 소아과

PURPOSE: This study was conducted to investigate the immune responses of children with moderate and severe novel influenza A virus (H1N1) pneumonia, and to compare their clinical and immunological findings with those of control subjects. METHODS: Thirty-two admitted patients with H1N1 pneumonia were enrolled in the study. The clinical profiles, humoral and cell-mediated immune responses of the 16 H1N1 pneumonia patients who were admitted to the pediatric intensive care unit (severe pneumonia group), 16 H1N1 pneumonia patients admitted to the pediatric general ward (moderate pneumonia group) and 13 control subjects (control group) were measured. RESULTS: Total lymphocyte counts were significantly lower in patients with H1N1 pneumonia than in the control group (P=0.02). The number of CD4+ T lymphocytes was significantly lower in the severe pneumonia group (411.5+/-253.5/microL) than in the moderate pneumonia (644.9+/-291.1/microL, P=0.04) and control (902.5+/-461.2/microL, P=0.01) groups. However, the number of CD8+ T lymphocytes was significantly higher in the severe pneumonia group (684.2+/-420.8/microL) than in the moderate pneumonia (319.7+/-176.6/microL, P=0.02) and control (407.2+/-309.3/microL, P=0.03) groups. The CD4+/CD8+ T lymphocytes ratio was significantly lower in the severe pneumonia group (0.86+/-0.24) than in the moderate pneumonia (1.57+/-0.41, P=0.01) and control (1.61+/-0.49, P=0.01) groups. The serum levels of IgG, IgM and IgE were significantly higher in the severe pneumonia group than in the 2 other groups. CONCLUSION: The results of this study suggest that increased humoral immune responses and the differences in the CD4+ and CD8+ T lymphocyte profiles, and imbalance of their ratios may be related to the severity of H1N1 pneumonia in children.

Development of an Inspector Training Program for Korean Blood Establishments / 대한수혈학회지

BACKGROUND: Standardized management and surveillance at a national level is essential to maintain blood product safety. Officials of the Korean Division of Human Blood Safety Surveillance, Korea Centers for Disease Control and Prevention, and Korean laboratory transfusion medicine specialists, currently participate as inspectors in the Korean National Blood Inspection Program for Blood Establishments. However, lack of definitive guidelines and absence of standardized inspector training programs compromise the goal of objective and consistent safety management results. In this study, we propose establishment of written inspection guidelines and a clearly documented accreditation training program. METHODS: Inspector training programs in the US and EU were reviewed online and the results of the Korean National Blood Inspection in our country performed during last 4 years were analyzed. RESULTS: We suggested inspection guidelines for every question of inspection checklists. Also, for the questions similar to those of Laboratory Accreditation Program of the Korean Society for Laboratory Medicine (KSLM), guidelines were proposed as 'Results of Laboratory Accreditation Program of the KSLM could be concerned if inspected laboratory obtained 2 year accreditation lately'. We suggest an 18hr-basic training program composed of lectures, e-learning and a visit to a blood center, as well as 12hr-continuing courses, should be established. CONCLUSION: To establish the Blood Inspection Program in a more systematic manner, thorough management and training of inspectors are essential. We expect the guidelines and training program for inspectors, suggested in our study, will be the cornerstone for creating a more professional quality management system and further ensure the safety of the national blood management system.

Immune Hemolytic Anemia after ABO-mismatched Liver Transplantation: A Case Report / 대한수혈학회지

Limitations due to lack of appropriate available donors for liver transplantation necessitates the use of ABO-mismatched donors. Transplantation of ABO-mismatched solid organs is sometimes associated with the development of immune hemolytic anemia, which is caused by production of antibodies by the donor B lymphocytes in a primary or secondary immune response against the recipient's red blood cell antigens. This condition is referred to as Passenger Lymphocyte Syndrome (PLS). PLS is more frequent in heart and lung transplants than in liver and kidney transplants with incidence of PLS in liver transplantation at 30~40%. When present, PLS typically manifests 1~3 weeks after transplantation, and subsides within 3 months after symptoms are first detected. In most patients, PLS is self-limiting and exhibits mild symptoms, but in some cases PLS can be life-threatening. We report a case of immune hemolytic anemia after an ABO-mismatched liver transplantation involving a blood group O donor and a blood group A recipient, and successful treatment of the resulting PLS symptoms by transfusion of gamma-irradiated group O Red Blood Cells (RBCs) accompanied by administration of 60 mg/day of methylprednisolone for 1 week.

IS6110-Restriction Fragment Length Polymorphism and Spoligotyping Analysis of Mycobacterium tuberculosis Clinical Isolates for Investigating Epidemiologic Distribution in Korea

The Beijing family of Mycobacterium tuberculosis has been emerging in the world. However, there are few nationwide data of genotypic distribution in Korea. This study aimed to identify the genotypic diversity of clinical isolates of M. tuberculosis and to demonstrate the population of Beijing family in Korea. We collected 96 clinical M. tuberculosis isolates from 11 university hospitals nationwide in Korea from 2008 to 2009. We observed 24 clusters in IS6110-RFLP analysis and 19 patterns in spoligotyping. Seventy-five isolates were confirmed to be Beijing family. Two isolates of the K strain and 12 isolates of the K family strain were also found. We found that drug resistance phenotypes were more strongly associated with Beijing family than non-Beijing family (P=0.003). This study gives an overview of the distribution of genotypes of M. tuberculosis in Korea. These findings indicate that we have to pay more attention to control of M. tuberculosis strains associated with the Beijing family.

Increase of Ceftazidime- and Fluoroquinolone-Resistant Klebsiella pneumoniae and Imipenem-Resistant Acinetobacter spp. in Korea: Analysis of KONSAR Study Data from 2005 and 2007

PURPOSE: Antimicrobial resistance monitoring could be a useful source of information for treating and controlling nosocomial infections. We analyzed antimicrobial resistance data generated by Korean Hospitals and by a commercial laboratory in 2005 and 2007. MATERIALS AND METHODS: Susceptibility data for 2005 and 2007 were collected from 37 and 41 hospitals, respectively, and from one commercial laboratory. Intermediate susceptibility was not included in the calculation of resistance rates. RESULTS: Methicillin-resistant Staphylococcus aureus (MRSA) (64%), third-generation cephalosporin-resistant Klebsiella pneumoniae (29%), fluoroquinolone-resistant Escherichia coli (27%), Pseudomonas aeruginosa (33%), and Acinetobacter spp. (48%), and amikacin-resistant P. aeruginosa (19%) and Acinetobacter spp. (37%) were prevalent in hospitals in 2007. A gradual increase of vancomycin-resistant Enterococcus faecium and imipenem-resistant Acinetobacter spp. was observed. Higher incidences of third-generation cephalosporin-resistant E. coli and K. pneumoniae and imipenem-resistant P. aeruginosa were found in the commercial laboratory than in the hospitals. CONCLUSION: Methicillin-resistant S. aureus, third-generation cephalosporin-resistant K. pneumoniae, and fluoroquinolone-resistant E. coli, P. aeruginosa and Acinetobacter spp. remain prevalent in Korea, while the incidence of vancomycin-resistant E. faecium and imipenem-resistant Acinetobacter spp. has increased gradually. The higher prevalences of third-generation cephalosporin-resistant E. coli and K. pneumoniae, and imipenem-resistant P. aeruginosa in the commercial laboratory are a new concern.

Carbapenem Resistance Mechanisms and Molecular Epidemiology of Acinetobacter spp. from Four Hospitals in Seoul and Gyeonggi Province in 2006 / 대한임상미생물학회지

BACKGROUND: Increasing numbers of Acinetobacter spp. resistant to multiple drugs, including carbapenem, has been a serious problem. The aims of this study were to determine carbapenem resistance patterns and mechanisms, as well as to study the molecular epidemiology of Acinetobacter spp. METHODS: Clinical isolates of Acinetobacter spp. were collected from May to November in 2006. Antimicrobial susceptibility testing was performed using CLSI disk diffusion and agar dilution methods. Metallo-beta-lactamase- and OXA carbapenemase-producing isolates were detected by PCR. Carbapenem resistance and hydrolytic activities were compared according to OXA type and presence of ISAba1. Pulsed-field gel electrophoresis (PFGE) was performed to determine the epidemiologic features. RESULTS: The imipenem non-susceptible rates were variable from 10% to 67%. Among 151 isolates carrying bla(OXA-51-like), 75 isolates carried both bla(OXA-51-like) and ISAba1, and 25 isolates had both bla(OXA-51-like), bla(OXA-23-like), and ISAba1. Carbapenem MICs of both bla(OXA-51-like) and ISAba1-carrying isolates were higher than those with bla(OXA-51-like) only. Carbapenem MICs of bla(OXA-23-like)-carrying isolates were higher than those with both bla(OXA-51-like) and ISAba1. Both bla(OXA-51-like) and ISAba1-carrying isolates and blaOXA-51-like, blaOXA-23-like, and ISAba1-carrying isolates demonstrated higher hydrolysis activities in oxacillin and carbapenems. Most of the tested isolates were susceptible to tigecycline, and all of them were susceptible to colistin. Pulsed-field gel electrophoresis suggested that there had been several outbreaks of bla(OXA-23-like) and bla(OXA-51-like)-positive strains. CONCLUSION: Carbapenem non-susceptible Acinetobacter isolates and OXA carbapenemase-producing isolates were prevalent. Dissemination of bla(OXA)-harboring isolates may make it difficult to treat infections due to carbapenem-resistant Acinetobacter spp. Further surveillance studies are required to prevent the spread of carbapenem resistance.

Identification of Bacterial and Fungal Isolates by Sequence Analysis of 16S rRNA and Internal Transcribed Spacer / 대한임상미생물학회지

BACKGROUND: Accurate and rapid identification of pathogens is one of the most important tasks of the clinical microbiology laboratory, and, in cases of rare pathogens, the identification is difficult and time-consuming upon the use of conventional methods alone. Herein, we will report our molecular work involving the identification of bacteria and fungi. METHODS: Sixty bacterial isolates had been collected from November 2004 to May 2007, and 15 fungal isolates had been collected from September 2005 to May 2007. Species identifications were performed using sequence analyses of the 16S rRNA region of bacteria and the internal transcribed spacer (ITS) region of fungi. The data were compared with those of GenBank (http://www.ncbi.nlm.nih.gov/) or EMBL (http://www.ebi.ac.uk/embl/). RESULTS: Sixty bacterial isolates included: 23 isolates with genus information (group 1), 17 isolates (group 2) that were too fastidious for genus or species identification, 16 isolates (group 3) with results from identification kits having low confidence, and 4 isolates (group 4) with odd antibiograms according to the species. In 58 of 60 isolates, identification of the genus or species could be obtained using molecular genetic methods. Thirty-eight isolates (63%) and 20 (33%) of 58 isolates could be identified at the species and genus levels, repectively. Among the total of 15 fungal isolates, 11 (73%) and 4 (27%) isolates were identified at the species and genus levels, respectively. CONCLUSION: 16S rRNA and ITS sequencing analyses are very useful for identifying the species or genus of a pathogenic microorganism in the clinical microbiology laboratory.

Investigation of Toxin Gene Diversity, Molecular Epidemiology, and Antimicrobial Resistance of Clostridium difficile Isolated from 12 Hospitals in South Korea / 대한진단검사의학회지

BACKGROUND: Clostridium difficile is a major cause of antibiotic-associated diarrhea. The objective of this study was to characterize clinical isolates of C. difficile obtained from various regions in Korea with regard to their toxin status, molecular type, and antimicrobial susceptibility. METHODS: We analyzed a total of 408 C. difficile isolates obtained between 2006 and 2008 from 408 patients with diarrhea in 12 South Korean teaching hospitals. C. difficile toxin genes tcdA, tcdB, cdtA, and cdtB were detected by PCR. Molecular genotyping was performed by PCR ribotyping. Antimicrobial susceptibilities of the 120 C. difficile isolates were assessed by agar dilution methods. RESULTS: Among 337 toxigenic isolates, 105 were toxin A-negative and toxin B-positive (A-B+) and 29 were binary toxin-producing strains. PCR ribotyping showed 50 different ribotype patterns. The 5 most frequently occurring ribotypes comprised 62.0% of all identified ribotypes. No isolate was susceptible to cefoxitin, and all except 1 were susceptible to piperacillin and piperacillin-tazobactam. The resistance rates of isolates to imipenem, cefotetan, moxifloxacin, ampicillin, and clindamycin were 25%, 34%, 42%, 51%, and 60%, respectively. The isolates showed no resistance to metronidazole or vancomycin. CONCLUSIONS: This is the first nationwide study on the toxin status, including PCR ribotyping and antimicrobial resistance, of C. difficile isolates in Korea. The prevalence of A-B+ strains was 25.7%, much higher than that reported from other countries. Binary toxin-producing strains accounted for 7.1% of all strains, which was not rare in Korea. The most prevalent ribotype was ribotype 017, and all A-B+ strains showed this pattern. We did not isolate strains with decreased susceptibility to metronidazole or vancomycin.

Evaluation of Various Formulae for Glomerular Filtration Rate Estimation and Proposal of New Formulae for the Korean Population / 대한진단검사의학회지

BACKGROUND: Some researchers have questioned the necessity of adjusting glomerular filtration rate (GFR) by body surface area (BSA). We compared the relationship between estimated GFR (eGFR) and radionuclide GFR (rGFR) with or without BSA adjustment by comparing the results obtained using various formulae with those obtained using 2 new proposed formulae. METHODS: A retrospective study was performed using 204 Korean individuals whose GFR had been estimated by the (99m)Tc-diethylenetriaminepentaacetic acid method between March 2004 and July 2008. We used the modification of diet in renal disease (MDRD) II formula, Mayo clinic quadratic (MCQ) formula, Cockcroft-Gault (CG) formula, and lean body mass-adjusted CG formula. Two new formulae, skeletal muscle mass index (SMI)-adjusted CG formula and SMIx3.4/SCr, were proposed by us. We analyzed each parameter with Pearson's correlation coefficient and also obtained the bias values. RESULTS: BSA did not satisfy the fundamental prerequisites of an adjustment factor for rGFR. MDRD II and MCQ GFR estimates demonstrated higher Pearson's correlation coefficient with BSA-unadjusted rGFR than they did with BSA-adjusted rGFR. The other GFR formulae estimates showed better correlation with rGFR and more favorable bias (P<0.001) when both GFR estimates and rGFR values were BSA-unadjusted. SMI-adjusted CG and SMIx3.4/SCr GFR estimates demonstrated correlation with rGFR and bias values similar to those of the MDRD II and CG GFR estimates. CONCLUSIONS: We suggest that absolute, non-corrected GFR and GFR estimate be preferred in daily practice. The absolute, non-corrected GFR and GFR estimate are considered helpful for patients with eGFR< or =60 mL/min/1.73 m2. We also recommend the clinical use of the new formulae, SMI-adjusted CG and SMIx3.4/SCr (BSA-unadjusted).

Infection Control Guideline for Hemodialysis Room / 병원감염관리

A hemodialysis room is the healthcare facility utmost demanding an infection control because dialysis patients have chronic serious underlying conditions and high risks of bloodborne infection due to a indwelling intravascular catheter, a frequent exposure to bloods or body fluids, and a blood transfusion as well as a hemodialysis room can be a mixing vessel to encounter both hospital-acquired pathogens and community-acquird pathogens. Therefore the Korean Society for Nosocomial Infection Control (KOSNIC) purposed to develop a guideline for the infection control in a hemodialysis room with support of Korean Center for Disease Control (KCDC). This guideline was composed of 11 chapters including vascular access control, dialysis water, microbiological and chemical monitoring of dialysis water and dialysates, components and passage of dialysates, maintenance of dialysis machines, disinfection, waste management, infection surveillance, aseptic techniques and standard precaution, environmental control, prevention of bloodborne infections and 5 appendices composing basic infection control techniques. This is the first official guideline approved by KOSNIC and KCDC of the infection control in a hemodialysis room in Korea. Here the guideline was published except appendices and entire guideline including those can be downloaded on hompages of KOSNIC (http://www.kosnic.org/) and KCDC (http//www.cdc.go.kr/).

Three Cases of Moraxella osloensis Meningitis: A Difficult Experience in Species Identification and Determination of Clinical Significance

We had three cases of Moraxella osloensis meningitis. The species identification was impossible by conventional and commercial phenotypic tests. However, we could identify the species using the 16S rRNA gene sequencing. Determination of clinical significance was difficult in one patient. All three patients recovered by appropriate antimicrobial therapy.