Prevalence of Helicobacter pylori infection and clarithromycin resistance rate from 2015 to 2018 using the laboratory information system of the Seegene Medical Foundation in Korea: a repeated cross-sectional study / 대한임상미생물학회지

Background@#Numerous studies have examined the prevalence of Helicobacter pylori infection and clarithromycin (CLA) resistance rate of H. pylori. However, in South Korea, there is a lack of research analyzing specimens from local clinics and hospitals using molecular methods. This study aimed to assess the prevalence of H. pylori infection and CLA resistance across sex and age groups, as well as to explore regional variations in CLA resistance and its characteristics. @*Methods@#Data from a laboratory information system from 2015 to 2018 were retrospectively analyzed to determine the prevalence of H. pylori infection and CLA resistance rate. The 23S ribosomal RNA genes of H. pylori were analyzed using a dual priming oligonucleotide-based multiplex polymerase chain reaction method. @*Results@#The overall prevalence of H. pylori infection was 50.5%(12,000/23,773), with a significantly higher prevalence among males (53.5%) than females (47.0%). The CLA resistance rate was 28.3%, with a significantly higher rate among females (34.9%) than males (23.8%). Age group analysis revealed that the highest prevalence of H. pylori infection was among individuals in their 40s, whereas the highest CLA resistance rate was observed among those in their 60s. The CLA resistance rate exhibited an upward trend and varied among patients based on their place of residence, and A2143G mutation was the most prevalent across all regions. @*Conclusion@#The prevalence of H. pylori infection and CLA resistance rate in Korea remain high and vary according to sex, age, and region. To effectively eradicate H. pylori, it is crucial to periodically monitor regional CLA resistance patterns and conduct CLA susceptibility testing before prescription.

Clinical usefulness of procalcitonin/albumin and blood urea nitrogen/albumin ratios for the early detection of bacteremia / 대한임상미생물학회지

Background@#Early prediction of bacteremia is important because sepsis may develop if bacteremia is not treated in time. We aimed to determine whether blood tests are clinically useful in predicting gram-negative versus gram-positive bacteremia. @*Methods@#We retrospectively analyzed the medical records of 16,569 patients who underwent blood culture testing among those who visited St. Mary’s Hospital of Uijeongbu, Catholic University from January 1, 2018 to December 31, 2018. After excluding 15,580 patients with insufficient data for analysis, the total study population was 989. @*Results@#In the multivariable logistic regression analysis for gram-negative bacteremia, after adjusting for major variables, procalcitonin (odds ratio [OR] 1.02, P < 0.001), high-sensitivity C-reactive protein (OR 1.03, P = 0.010), and albumin (OR 0.55, P = 0.010) were significant. In the same model, lactic acid (OR 1.08, P = 0.010), blood urea nitrogen (BUN) (OR 1.02, P = 0.010), and albumin (OR 0.50, P = 0.005) were significant for gram-positive bacteremia.We constructed blood indicators by combining blood tests that were significant in multivariable logistic regression analysis. Comparing the area under the curve (AUC) of the receiver operating characteristic curve, the AUC of the procalcitonin/albumin ratio in gramnegative bacteremia was significantly higher than that of procalcitonin (0.846 vs. 0.837, P = 0.005), and the AUC of the BUN/albumin ratio in gram-positive bacteremia was significantly higher than that of BUN (0.709 vs. 0.679, P = 0.007). @*Conclusion@#The procalcitonin/albumin ratio is expected to be helpful in the early prediction of gram-negative bacteremia, whereas the BUN/albumin ratio in the early prediction of grampositive bacteremia.

Serotype Distribution and Antimicrobial Resistance of Streptococcus pneumoniae Causing Invasive Pneumococcal Disease in Korea Between 2017 and 2019 After Introduction of the 13-Valent Pneumococcal Conjugate Vaccine

Background@#Streptococcus pneumoniae is a serious pathogen causing various infections in humans. We evaluated the serotype distribution and antimicrobial resistance of S. pneumoniae causing invasive pneumococcal disease (IPD) after introduction of pneumococcal conjugate vaccine (PCV)13 in Korea and investigated the epidemiological characteristics of multidrug-resistant (MDR) isolates. @*Methods@#S. pneumoniae isolates causing IPD were collected from 16 hospitals in Korea between 2017 and 2019. Serotyping was performed using modified sequential multiplex PCR and the Quellung reaction. Antimicrobial susceptibility tests were performed using the broth microdilution method. Multilocus sequence typing was performed on MDR isolates for epidemiological investigations. @*Results@#Among the 411 S. pneumoniae isolates analyzed, the most prevalent serotype was 3 (12.2%), followed by 10A (9.5%), 34 (7.3%), 19A (6.8%), 23A (6.3%), 22F (6.1%), 35B (5.8%), 11A (5.1%), and others (40.9%). The coverage rates of PCV7, PCV10, PCV13, and pneumococcal polysaccharide vaccine (PPSV)23 were 7.8%, 7.8%, 28.7%, and 59.4%, respectively. Resistance rates to penicillin, ceftriaxone, erythromycin, and levofloxacin were 13.1%, 9.2%, 80.3%, and 4.1%, respectively. MDR isolates accounted for 23.4% of all isolates. Serotypes 23A, 11A, 19A, and 15B accounted for the highest proportions of total isolates at 18.8%, 16.7%, 14.6%, and 8.3%, respectively. Sequence type (ST)166 (43.8%) and ST320 (12.5%) were common among MDR isolates. @*Conclusions@#Non-PCV13 serotypes are increasing among invasive S. pneumoniae strains causing IPD. Differences in antimicrobial resistance were found according to the specific serotype. Continuous monitoring of serotypes and antimicrobial resistance is necessary for the appropriate management of S. pneumoniae infections.

Inhibitory Effects of Copper, Brass, and Stainless Steel Surfaces on Multidrug-Resistant Microorganisms / 대한임상미생물학회지

Background@#The aim of this study was to analyze the inhibitory effects of copper, brass (78% copper, 22% tin), and stainless steel surfaces on multidrug-resistant Acinetobacter baumannii (MRAB), extended-spectrum beta-lactamase (ESBL) Escherichia coli , and carbapenem-resistant Klebsiella pneumoniae (CRKP). @*Methods@#MRAB, ESBL E. coli, and CRKP were isolated at Uijeongbu St. Mary's Hospital in 2020. A. baumannii ATCC BAA-747, E. coli ATCC 25922, and K. pneumoniae ATCC 700603 were used as reference strains. The initial bacterial cell count of each inoculum was adjusted to 8 log CFU/mL using phosphate buffered saline, Copper, brass, and stainless steel plates were inoculated with 9 mL of MRAB, ESBL E. coli, and CRKP inoculum solutions. The bacterial cell count was measured from the beginning to the 20th day in an incubator maintained at 35°C. @*Results@#MRAB, ESBL E. coli, and CRKP isolates were not detected on the copper and brass plates after 4, 5.5, and 6.5 hours, respectively. MRAB, ESBL E. coli, and CRKP isolates were not detected on the stainless steel plate after 15, 20, and 20 days, respectively. The bactericidal effects of copper and brass were much stronger than those of stainless steel. @*Conclusion@#The use of copper and copper alloys should be considered to prevent crossinfection in hospitals.

Epidemiologic Linkage of COVID-19Outbreaks at Two University-affiliated Hospitals in the Seoul Metropolitan Area in March 2020

Background@#Coronavirus disease 2019 (COVID-19) outbreaks emerged at two universityaffiliated hospitals in Seoul (hospital A) and Uijeongbu City (hospital S) in the metropolitan Seoul area in March 2020. The aim of this study was to investigate epidemiological links between the outbreaks using whole genome sequencing (WGS) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). @*Methods@#Fifteen patients were enrolled in the study, including four non-outbreak (A1–A4) and three outbreak cases (A5–A7) in hospital A and eight cases (S1–S8) in hospital S. Patients' hospital stays, COVID-19 symptoms, and transfer history were reviewed. RNA samples were submitted for WGS and genome-wide single nucleotide variants and phylogenetic relationships were analyzed. @*Results@#The index patient (A5) in hospital A was transferred from hospital S on 26 March.Patients A6 and A7 were the family caregiver and sister, respectively, of the patient who shared a room with A5 for 4 days. Prior to transfer, A5 was at the next bed to S8 in the emergency room on 25 March. Patient S6, a professional caregiver, took care of the patient in the room next to S8's room for 5 days until 22 March and then S5 for another 3 days.WGS revealed that SARS-CoV-2 in A2, A3, and A4 belong to clades V/B.2, S/A, and G/B.1, respectively, whereas that of A5–A7 and S1-S5 are of the V/B.2.1 clade and closely clustered. In particular, SARS-CoV-2 in patients A5 and S5 showed perfect identity. @*Conclusion@#WGS is a useful tool to understand epidemiology of SARS-CoV-2. It is the first study to elucidate the role of patient transfer and caregivers as links of nosocomial outbreaks of COVID-19 in multiple hospitals.

Psychosocial Stress, Memory, and Successful Aging of the Community-Residing Elderly / 農村醫學 地域保健

Objectives@#The purpose of this study is to identify the relationship among psychosocial stress, memory, and successful aging of the community-residing elderly. @*Methods@#152 people over 65 years old living in D area were interviewed, from August 1st, 2020 to October 30th, 2020. The outcomes were measured by Psychosocial Well-being Index (PWI), Mini-Memory Test (MiMeT) and successful aging. Data were analyzed using Pearson correlation coefficients and stepwise multiple regression. @*Results@#There was a positive correlation between successful aging and memory. There was a negative correlation between psychosocial stress and successful aging, and between psychosocial stress and memory. Psychosocial stress was identified as a predictor of successful aging, which explained 26.4% of total variance of successful aging. @*Conclusions@#When we prepare intervention programs which improve successful aging for community-residing older adults, we need to consider psychosocial stress. In addition, stress management programs for successful aging should be developed to improve current successful aging.

Evaluating Diagnostic Tests for Helicobacter pylori Infection Without a Reference Standard: Use of Latent Class Analysis

Evaluation of diagnostic tests requires reference standards, which are often unavailable. Latent class analysis (LCA) can be used to evaluate diagnostic tests without reference standards, using a combination of observed and estimated results. Conditionally independent diagnostic tests for Helicobacter pylori infection are required. We used LCA to construct a reference standard and evaluate the capability of non-invasive tests (stool antigen test and serum antibody test) to diagnose H. pylori infection compared with the conventional method, where histology is the reference standard. A total of 96 healthy subjects with endoscopy histology results were enrolled from January to July 2016. Sensitivity and specificity were determined for the LCA approach (i.e., using a combination of three tests as the reference standard) and the conventional method. When LCA was used, sensitivity and specificity were 83.8% and 99.4% for histology, 80.0% and 81.9% for the stool antigen test, and 63.6% and 89.3% for the serum antibody test, respectively. When the conventional method was used, sensitivity and specificity were 75.8% and 71.1% for the stool antigen test and 77.7% and 60.7% for the serum antibody test, respectively. LCA can be applied to evaluate diagnostic tests that lack a reference standard.

A Case Report of Saccharomyces cerevisiae Fungemia in a Premature Infant Following Probiotic Treatment / 대한임상미생물학회지

Probiotics are used to restore and maintain the healthy intestinal microflora. Although Saccharomyces cerevisiae (SC) is considered as a non-pathogenic yeast, administration of SC as a probiotic is associated with a rare cause of fungemia in immunocompromised patients with central venous catheter insertion. We encountered a case of SC fungemia in a premature infant who presented with respiratory distress syndrome and had undergone central venous catheterization.

Development of a Label-Free LC-MS/MS-Based Glucosylceramide Synthase Assay and Its Application to Inhibitors Screening for Ceramide-Related Diseases

Ceramide metabolism is known to be an essential etiology for various diseases, such as atopic dermatitis and Gaucher disease. Glucosylceramide synthase (GCS) is a key enzyme for the synthesis of glucosylceramide (GlcCer), which is a main ceramide metabolism pathway in mammalian cells. In this article, we developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to determine GCS activity using synthetic non-natural sphingolipid C8-ceramide as a substrate. The reaction products, C8-GlcCer for GCS, could be separated on a C18 column by reverse-phase high-performance liquid chromatography (HPLC). Quantification was conducted using the multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 588.6 → 264.4 for C8-GlcCer at positive ionization mode. The calibration curve was established over the range of 0.625–160 ng/mL, and the correlation coefficient was larger than 0.999. This method was successfully applied to detect GCS in the human hepatocellular carcinoma cell line (HepG2 cells) and mouse peripheral blood mononuclear cells. We also evaluated the inhibition degree of a known GCS inhibitor 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP) on GCS enzymatic activity and proved that this method could be successfully applied to GCS inhibitor screening of preventive and therapeutic drugs for ceramide metabolism diseases, such as atopic dermatitis and Gaucher disease.

Multicenter Comparison of Four Automated Immunoassay Analyzers for Prostate Specific Antigen

No abstract available.

Development of Statistical Software for the Korean Laboratory Accreditation Program Using R Language: LaboStats

BACKGROUND: In Korea, the Korean Laboratory Accreditation Program (KLAP) has set minimum standards for verification of clinical test performance. This verification process is time-consuming and labor-intensive when performed manually. We developed a free, statistical software program for KLAP, using the R language (R Foundation for Statistical Computing, Vienna, Austria). METHODS: We used CLSI guidelines for the algorithm. We built graphic user interfaces, including data input, with Embarcadero Delphi EX4 (Embarcadero Technologies, Inc., Texas, USA). The R Base Package and MCR Package for Method Comparison Regression were used to implement statistical and graphical procedures. RESULTS: Our program LaboStats has six modules: parallel test, linearity, method comparison, precision, reference interval, and cutoff. Data can be entered into the field either manually or by copying and pasting from an MS Excel worksheet. Users can print out precise reports. CONCLUSIONS: LaboStats can be useful for evaluating clinical test performance characteristics and preparing documents requested by KLAP.

Serotype Distribution and Antimicrobial Resistance of Invasive and Noninvasive Streptococcus pneumoniae Isolates in Korea between 2014 and 2016

BACKGROUND: Several factors contribute to differences in Streptococcus pneumoniae serotype distribution. We investigated the serotype distribution and antimicrobial resistance of S. pneumoniae isolated between 2014 and 2016 in Korea. METHODS: We collected a total of 1,855 S. pneumoniae isolates from 44 hospitals between May 2014 and May 2016, and analyzed the serotypes by sequential multiplex PCR. We investigated the distribution of each serotype by patient age, source of the clinical specimen, and antimicrobial resistance pattern. RESULTS: The most common serotypes were 11A (10.1%), followed by 19A (8.8%), 3 (8.5%), 34 (8.1%), 23A (7.3%), and 35B (6.2%). The major invasive serotypes were 3 (12.6%), 19A (7.8%), 34 (7.8%), 10A (6.8%), and 11A (6.8%). Serotypes 10A, 15B, 19A, and 12F were more common in patients ≤5 years old, while serotype 3 was more common in patients ≥65 years old compared with the other age groups. The coverage rates of pneumococcal conjugate vaccine (PCV)7, PCV10, PCV13, and pneumococcal polysaccharide vaccine 23 were 11.8%, 12.12%, 33.3%, and 53.6%, respectively. Of the 1,855 isolates, 857 (46.2%) were multi-drug resistant (MDR), with serotypes 11A and 19A predominant among the MDR strains. The resistance rates against penicillin, cefotaxime, and levofloxacin were 22.8%, 12.5%, and 9.4%, respectively. CONCLUSIONS: There were significant changes in the major S. pneumoniae serotypes in the community. Non-PCV13 serotypes increased in patients ≤5 years old following the introduction of national immunization programs with the 10- and 13-polyvalent vaccines.

Intactness of Medical Nonsterile Gloves on Use of Alcohol Disinfectants

No abstract available.

Multicenter Study on the Association of Positive Helicobacter pylori Stool Antigen to Anemia in Children / 대한임상미생물학회지

BACKGROUND: Helicobacter pylori infection in children causes gastrointestinal symptoms and iron deficiency anemia. This study aimed to investigate trends in H. pylori stool antigen (HpSA) positivity in children and the relationship between HpSA test results and anemia. METHODS: We analyzed the results of 2,762 HpSA tests and the correlation of hemoglobin and ferritin with HpSA in patients aged 0–18 years from 2008 to 2014 at a tertiary care center. Additionally, we prospectively evaluated HpSA test results and correlation with hemoglobin in 352 specimens obtained from five centers. RESULTS: From 2008-2014, the mean positive rate of the HpSA test was 5.8%, with a high of 9.1% in 2012 and a low of 2.3% in 2013. The positive rate correlated with age: 2.9% in 0–6-year-olds, 5.8% in 7–12-year-olds, and 10.6% in 13–18-year-olds (P < 0.0001). There was no difference in HpSA positivity in patients with (7.0%) and without (5.7%) anemia. Ferritin was significantly lower in patients with positive HpSA results than in those with negative results (P=0.0001). In a multicenter study, the positive rate of HpSA was 16.8%. CONCLUSION: The rate of HpSA positivity was 5.8% in pediatric patients at a single center from 2008–2014, and this rate increased with age. Helicobacter pylori infection may be associated with iron deficiency, as ferritin level was significantly lower in HpSA-positive patients than HpSA-negative patients.

Inhibitory Effect of Metal Surface on the Antimicrobial Resistance Microorganism / 대한임상미생물학회지

BACKGROUND: The aim of this study was to comparatively evaluate the bactericidal effects of copper, brass (copper 78%, tin 22%), and stainless steel against methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus faecium (VREFM), and multidrug-resistant Pseudomonas aeruginosa (MRPA). METHODS: The isolates (MRSA, VREFM, MRPA) used in this study were mixed wild type 3 strains isolated from patients treated at Uijeongbu St. Mary's Hospital in 2017. These strains showed patterns of multidrug resistance. The lyophilized strains were inoculated into and incubated for 24 hr in tryptic soy broth at 35℃. The initial bacterial inoculum concentration was adjusted to 105 CFU/mL. A 100-mL bacterial suspension was incubated in containers made of brass (copper 78%, tin 22%), copper (above 99% purity), and stainless steel at 35℃. Viable counts of bacteria strains were measured for 9 days. RESULTS: In this study, the bactericidal effects of copper and brass on MRSA, VREFM, and MRPA were verified. The bactericidal effect of stainless steel was much weaker than those of copper and brass. The bactericidal effect was stronger on MRPA than on MRSA or VREFM. CONCLUSION: To prevent cross infection of multidrug resistant bacteria in hospitals, further studies of longer duration are needed for testing of copper materials on objects such as door knobs, faucets, and bed rails.

Circulating Microparticles and Coagulation Profiles in Patients with Advanced Stage Solid Tumors

No abstract available.

Performance Evaluation of Elecsys Vitamin D Total II Assay Using Roche Modular Analytics E170

We evaluated the performance of a recently developed immunoassay, Elecsys vitamin D total II assay (Roche Diagnostics GmbH, Germany). Precision, linearity, and comparison studies were performed according to the Clinical and Laboratory Standards Institute guidelines. Control materials, linearity materials, and patient samples were used for the evaluation. For the correlation study, liquid chromatography-tandem mass spectrometry was used as the comparative method. Total coefficients of variations of the analyte were between 5.1% and 9.6%. The results of linearity evaluation were also acceptable for the range tested. Correlations with comparative methods were good; however, the mean values of the Elecsys vitamin D assay were higher than those of liquid chromatography-tandem mass spectrometry. The overall analytical performance of the Elecsys vitamin D total II assay is acceptable for the immunology analyzer. Therefore, the Elecsys vitamin D total II assay is expected to be widely used.

The Role of Endoscopic Biliary Drainage without Sphincterotomy in Gallstone Patients with Cholangitis and Suspected Common Bile Duct Stones Not Detected by Cholangiogram or Intraductal Ultrasonography

BACKGROUND/AIMS: Treatment for cholangitis without common bile duct (CBD) stones has not been established in patients with gallstones. We investigated the usefulness of endoscopic biliary drainage (EBD) without endoscopic sphincterotomy (EST) in patients diagnosed with gallstones and cholangitis without CBD stones by endoscopic retrograde cholangiopancreatography (ERCP) and intraductal ultrasonography (IDUS). METHODS: EBD using 5F plastic stents without EST was performed prospectively in patients with gallstones and cholangitis if CBD stones were not diagnosed by ERCP and IDUS. After ERCP, all patients underwent laparoscopic cholecystectomy. The primary outcomes were clinical and technical success. The secondary outcomes were recurrence rate of biliary events and procedure-related adverse events. RESULTS: Among 187 patients with gallstones and cholangitis, 27 patients without CBD stones according to ERCP and IDUS received EBD using 5F plastic stents without EST. The stents were maintained in all patients until laparoscopic cholecystectomy, and recurrence of cholangitis was not observed. After cholecystectomy, the stents were removed spontaneously in 12 patients and endoscopically in 15 patients. Recurrence of CBD stones was not detected during the follow-up period (median, 421 days). CONCLUSIONS: EBD using 5F plastic stents without EST may be safe and effective for the management of cholangitis accompanied by gallstones in patients without CBD stones according to ERCP and IDUS.

Clinical and Genetic Features of Coxiella burnetii in a Patient with an Acute Febrile Illness in Korea

Although Q fever is an important zoonotic infection with a worldwide distribution, no human isolates of Coxiella burnetii have been identified in Korea. For the first time, we identified the nucleotide sequence of C. burnetii from a 32-year-old man with an acute febrile illness in Korea. Diagnosis of acute Q fever was confirmed by seroconversion using indirect immunofluorescence antibody assays. Phylogenetic analysis demonstrated high sequence similarity (99.6%–100%) with C. burnetii 16S rRNA sequences identified from the reservoir. These results are the first genetic analysis of C. burnetii in a human case of Q fever in Korea.

Meeting Highlights: The Second Consensus Conference for Breast Cancer Treatment in Korea / 한국유방암학회지

The Korean clinical practice guideline recently developed by the Korean Breast Cancer Society to address the national clinical situation is currently under revision ahead of a seventh recommendation. A second consensus conference was held to further develop this guideline by soliciting opinions regarding important issues related to surgery, radiotherapy, and medical oncology. Several issues were discussed, and the discussion progressed to pros and cons in the context of cases in various clinical situations. The panels discussed and voted on issues regarding surgical treatment for non-axillary regional lymph nodes, regional nodal irradiation of pN1 disease, and ovarian functional suppression (OFS) as an adjuvant treatment in premenopausal patients with hormone receptor-positive breast cancer. Regarding the surgical treatment of non-axillary regional lymph node, most panelists agreed with the recommendation of preoperative chemotherapy and postoperative radiotherapy for patients with biopsy-diagnosed metastases, whereas surgery or radiotherapy of non-axillary regional lymph nodes was suggested for clinical partial responders. Discussions on radiotherapy addressed the need for adjuvant radiotherapy and radiation field of regional lymph node in the context of various N1 breast cancer cases. The participants reached a consensus to recommend that N1 patients should receive regional nodal irradiation for a large tumor burden (e.g., three positive nodes, perinodal extension, or large primary tumor). Finally, the panels favored OFS in addition to endocrine therapy for premenopausal women with high risk factors such as a large tumor size, involvement of more than three nodes, and a high histologic grade.