BACKGROUND: The recovery of bacteria from blood can be affected by many factors. Standardization of blood culture methods is important for reliability. Herein, we aimed to investigate blood culture protocols in Korea. METHODS: We performed a multicenter survey with a questionnaire about blood culture practices, which was sent by email to directors and clinical physicians in charge of clinical microbiology laboratories in May 2014. Total data from 18 participating hospitals were analyzed to be used as current baseline data, which is necessary to optimize blood culture protocols. RESULTS: Many laboratories included recommended blood volume, which is a major factor for bacteria recovery rate. This varied across participating laboratories. For adults, blood sampling of 10 mL was recommended by 10 laboratories and 20 mL was recommended by 5 laboratories. For children who weighed 14-36 kg and less than 14 kg, blood sampling of 10 mL (n=8) and 5 mL (n=7) was recommended, respectively. For neonates, less than 1 mL was recommended by 12 laboratories. CONCLUSION: Substantial variations in blood culture protocols were seen across participating clinical microbiology laboratories. Efforts to standardize this protocol should be undertaken.
Adult ; Bacteria ; Blood Volume ; Child ; Electronic Mail ; Humans ; Infant, Newborn ; Korea* ; Sepsis

The dissemination of multidrug-resistant (MDR) pathogen is of major public health concern as it leads to increased mortality rate, length of hospital stays, and medical expenses.Current Concepts: Korean Government enacted an Infectious Disease Control and Prevention Act in 2009, and 6 MDR bacteria including methicillin-resistant Staphylococcus aureus, vancomycin-resistant S. aureus (VRSA), vancomycin-resistant enterococci, multidrug-resistant Pseudomonas aeruginosa, multidrug-resistant Acinetobacter baumannii, and carbapenem-resistant Enterobacterales (CRE) have been legally declared as infectious diseases. According to the amendment of the Infectious Disease Control and Prevention Act in 2020, CRE and VRSA were classified as class 2 infectious diseases, and all cases of CRE and VRSA should be reported to the Korea Disease Control and Prevention Agency (KDCA). Methicillin-resistant S. aureus, vancomycin-resistant enterococci, multidrug-resistant P. aeruginosa, and multidrug-resistant A. baumannii were classified as class 4 infectious diseases, and cases that occur need to be monitored at KDCA-designated sentinel hospitals to prevent further dissemination.Discussion and Conclusion: In this review, the current antimicrobial resistance status of six types of MDR bacteria, legally declared as infectious diseases, was investigated.. The Korean government is operating national antimicrobial resistance surveillance systems such as the Korean Antimicrobial Resistance Monitoring System and Korean Global Antimicrobial Surveillance System, as a foundation for preventing the spread of antimicrobial resistance. Certain steps need to be taken, such as establishing a surveillance system for antimicrobial usages, strengthening antimicrobial stewardship and infection control systems, and developing new antimicrobials in order for us to achieve the national goal.

Background: There has been a marked increase in the mortality rate associated with Clostridioides difficile infection (CDI) globally since 2003, with the emergence of binary toxinproducing ribotype 027 strains. However, the molecular epidemiology of C. difficile shows regional differences and ribotype 027 is not common in Korea. In this study, the risk factors for severe CDI were evaluated, while considering the region-specific molecular epidemiology. Methods: A retrospective case-control study was performed. Cases (n = 149) included patients with severe CDI or severe complicated CDI. Controls (n = 155) consisted of patients with nonsevere CDI. Results: Advanced age (odds ratio [OR] = 1.017, P = 0.0358), a history of chemotherapy (OR = 2.695, P = 0.0464), and ribotype 002 (OR = 3.406, P = 0.0231) were statistically significant factors associated with severe CDI in a multivariate analysis. Conclusion Ribotype 002 was found to be a significant risk factor for severe CDI in this study.Therefore, the surveillance of C. difficile ribotypes is recommended to monitor the spread of high-risk clones.

Background: The incidence of community-associated (CA) Clostridioides difficile infection (CDI) has increased in Korea. In this study, we evaluated CA-CDI risk factors in terms of clinical features and ribotype considering its region-specific molecular epidemiology. Methods: A retrospective case-control study was performed on two groups of CDI patients:127 subjects with CA-CDI and 265 subjects with healthcare-associated (HA)-CDI. Risk factors for CA-CDI were evaluated in terms of clinical and microbiological features such as toxin type and ribotype. Results: A comparison of the two groups of CDI patients revealed that inflammatory bowel disease, diarrhea, abdominal pain, and fever were more closely associated with CA-CDI. The toxin types and ribotypes of C. difficile were similar between the two groups. After adjusting for variables, no risk factors were identified for CA-CDI compared with HA-CDI. Conclusion Specific risk factors for CA-CDI were not identified in this study.

BACKGROUND: Fecal occult blood tests have been widely used to screen for colorectal cancer. SENTiFIT 270 (Sentinel diagnostics, Italy) is a fecal occult blood test with an immunochemical method that utilizes FOB Gold reagents. We evaluated the performance of SENTiFIT 270 using the FOB Gold reagent. In addition, FOB Gold was evaluated with the HITACHI 7180 (Hitachi Ltd., Japan). METHODS: The precision and linearity of the SENTiFIT 270 was evaluated in accordance with applicable Clinical and Laboratory Standard Institute guidelines. The comparison study between SENTiFIT 270-FOB Gold and the OC-Sensor (Eiken chemical Co., Japan) was performed using stool specimens. RESULTS: In the precision evaluation, the total precision of SENTiFIT 270-FOB Gold was 4.94% and 2.54% at high and low concentrations, respectively. The HITACHI 7180-FOB Gold had excellent precision of 4.60% and 2.09% at high and low concentrations, respectively. Linearity was also excellent for the SENTiFIT 270-FOB Gold and HITACHI 7180-FOB Gold at 0.9987 and 0.9986, respectively. The SENTITIF 270-FOB Gold showed excellent agreement with a kappa value of 0.830 and a concordance rate of 93.6%. The HITACHI 7180-FOB Gold showed high agreement with a kappa value of 0.832 and a concordance rate of 93.9%. CONCLUSION: The SENTiFIT 270-FOB Gold showed excellent performance in accuracy, linearity, and comparative inspection ability.
Colonic Neoplasms ; Colorectal Neoplasms ; Indicators and Reagents ; Methods ; Occult Blood

No abstract available.
Bacteremia ; Immunocompromised Host ; Korea

Methods: A total of 889 non-duplicated clinical isolates were included in this study. The results of ASTA MicroIDSys were compared with those of Bruker Biotyper; 16S rRNA sequencing was performed for the species for which results obtained using the two systems did not match. The sequences of rpoB, hisA, and/or recA for the clinical isolates of Acinetobacter species, Klebsiella species, and Burkholderia cepacia complex were analyzed and used as reference identifications. Results: The concordance rates for bacterial identification using ASTA MicroIDSys and Bruker Biotyper were 100% at the genus level and 98.3% at the species level for isolates belonging to the order Enterobacterales. Similarly, the concordance rates at the genus and species levels were 98.8% and 91.0% for glucose non-fermenting bacilli, 100% and 100% for gram-positive cocci, and 98.9% and 98.9% for other isolates, respectively. ASTA MicroIDSys was expected to correctly identify 97.9% of the 108,251 isolates identified in our clinical microbiology laboratory over the past 5 years. Conclusion ASTA MicroIDSys showed excellent performance in bacterial identification for most of the clinically relevant species. Further extension of the database could improve the identification accuracy of ASTA MicroIDSys.

Background: The prevalence of carbapenemase-producing Enterobacteriaceae (CPE), especially the KPC-2-producing Klebisella pneumoniae, is rapidly increasing and becoming a menace to global public health. This study aims to present the molecular epidemiology of the KPC-2-producing K. pneumoniae isolates emerged in a tertiary hospital in South Korea and describe its clinical significance. Methods: This study included carbapenem-resistant K. pneumoniae isolates collected from a tertiary hospital from April to December in 2018. Antimicrobial susceptibility of K. pneumoniae isolates was tested using disk diffusion method. PCR and DNA sequence analyses were performed to identify the resistance genotype. In addition, the molecular epidemiology was investigated using pulsed-field gel electrophoresis (PFGE) and multilocus sequencing typing (MLST). Results: Total 100 KPC-2-producing K. pneumoniae isolates were collected, which were mainly classified into two pulsotypes according to the XbaI restriction digestion pattern by PFGE analysis (pulsotype A, n = 31; pulsotype B, n = 63). The isolates exhibiting pulsotype A belonged to ST395 and the remaining isolates exhibiting pulsotype B were attributed to ST307 by MLST analysis. Conclusion This study investigated clinical information and molecular bacterial profiles for KPC-2-producing K. pneumoniae isolates. These findings indicate that the proper infection control activities are needed to prevent the spread of multidrug-resistant organisms such as CPE, which could cause high mortality in clinical field.

BACKGROUND: The increasing morbidity and mortality rates associated with Acinetobacter baumannii are due to the emergence of drug resistance and the limited treatment options. We compared characteristics of colistin-resistant Acinetobacter baumannii (CR-AB) clinical isolates recovered from patients with and without prior colistin treatment. We assessed whether prior colistin treatment affects the resistance mechanism of CR-AB isolates, mortality rates, and clinical characteristics. Additionally, a proper method for identifying CR-AB was determined. METHODS: We collected 36 non-duplicate CR-AB clinical isolates resistant to colistin. Antimicrobial susceptibility testing, Sanger sequencing analysis, molecular typing, lipid A structure analysis, and in vitro synergy testing were performed. Eleven colistin-susceptible AB isolates were used as controls. RESULTS: Despite no differences in clinical characteristics between patients with and without prior colistin treatment, resistance-causing genetic mutations were more frequent in isolates from colistin-treated patients. Distinct mutations were overlooked via the Sanger sequencing method, perhaps because of a masking effect by the colistin-susceptible AB subpopulation of CR-AB isolates lacking genetic mutations. However, modified lipid A analysis revealed colistin resistance peaks, despite the population heterogeneity, and peak levels were significantly different between the groups. CONCLUSIONS: Although prior colistin use did not induce clinical or susceptibility differences, we demonstrated that identification of CR-AB by sequencing is insufficient. We propose that population heterogeneity has a masking effect, especially in colistin non-treated patients; therefore, accurate testing methods reflecting physiological alterations of the bacteria, such as phosphoethanolamine-modified lipid A identification by matrix-assisted laser desorption ionization-time of flight, should be employed.
Acinetobacter baumannii* ; Acinetobacter* ; Bacteria ; Colistin* ; Drug Resistance ; Humans ; In Vitro Techniques ; Lipid A ; Masks ; Methods ; Molecular Typing ; Mortality ; Population Characteristics