BACKGROUND: Workers in the microbiology laboratories are continuously exposed to the risk of laboratory-associated infections. Tuberculosis (TB) is a frequent laboratory-acquired infection owing to production of cough-generated aerosols with ease and high infectivity of Mycobacterium tuberculosis. This study aims to investigate the current situation of biosafety in Korean TB laboratories. METHODS: We conducted a nationwide survey of laboratories in hospitals conducting TB tests using questionnaires about their facility and management standards. RESULTS: We analyzed data from 52 hospitals nationwide that have a capacity of 100–2,000 beds, of which only two laboratories conduct high risk drug-susceptibility testing on cultured isolates among other test items, whereas six laboratories perform only direct sputum-smear microscopy. The remaining laboratories performed moderate-risk activities/tests, like sample processing for culture. In the majority of these laboratories, there are laboratory medicine specialists who are fully in charge of health checkup programs for laboratorians. The facility and management standards vary widely according to the size of the hospital and risk of TB tests. CONCLUSIONS: Our survey results about the current situation of TB laboratories could be useful as baseline data for preparing biosafety guidelines for all TB laboratories in Korea.
Aerosols ; Korea* ; Microscopy ; Mycobacterium tuberculosis ; Specialization ; Tuberculosis*

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, with its accuracy and speed, is widely used for bacterial identification. The ASTA MicroIDSys system (ASTA, Korea) was recently developed for species identification. We compared its performance with that of Bruker Biotyper (Bruker Daltonics, Germany). Microbes were recovered from sputum, urine, and pus samples from patients admitted to a tertiary care hospital in Korea from January to April 2016. Matrix solution (α-cyano-4-hydroxycinnamic acid) was used, and the peptide profiles acquired from the Microflex LT (Bruker Daltonics) and Tinkerbell LT (ASTA) were analyzed by using their respective software. From 5,322 isolates, Bruker Biotyper identified 163 species; fifty species from 4,919 isolates were identified more than 10 times, including Klebsiella pneumoniae (n=571), Acinetobacter baumannii (n=436), Pseudomonas aeruginosa (n=358), Escherichia coli (n=372), Staphylococcus aureus (n=511), S. epidermidis (n=444), Enterococcus faecium (n=262), E. faecalis (n=220), and Candida albicans (n=248). Identical results, confidence scores (≥ 2.0 for Bruker Biotyper), and acceptable scores (≥140 for ASTA MicroIDSys) were obtained for 86.1% of isolates. Of 4,267 isolates, 99.2% showed acceptable scores in both systems. Results from the ASTA MicroIDSys showed good agreement with those from the Bruker Biotyper. The ASTA MicroIDSys could reliably identify clinically important microorganisms.
Acinetobacter baumannii ; Candida albicans ; Enterococcus faecium ; Escherichia coli ; Humans ; Klebsiella pneumoniae ; Korea ; Mass Spectrometry* ; Pseudomonas aeruginosa ; Sputum ; Staphylococcus aureus ; Suppuration ; Tertiary Healthcare

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

BACKGROUND: Cladosporium spp. are dematiaceous fungi that are commonly isolated from indoor and outdoor environments, including hospital air. This fungus is rarely pathogenic to humans, but has been reported to cause infections of the skin and toenails, as well as sinusitis and pulmonary infections. The monitoring of culture results was conducted to identify the outbreak of an unknown black fungal infection between January and March 2006 in a University hospital, and infection control activity was performed to identify the cause of the outbreak. METHODS: An epidemiological investigation of 22 patients with infections caused by an unknown black fungus was conducted. Microscopic examination and molecular analysis on the internal transcript spacer (ITS) region was performed to identify the black fungus. To detect the source of contamination, a culture of environmental specimens was performed, and then, disinfection of the laboratory was implemented. RESULTS: The patients with black fungi belonged to various departments and wards. No symptoms of fungal infection were recognized on the basis of the survey. The black fungus was identified as Cladosporium spp. on the basis of morphological features and ITS region sequencing. Culturing of environmental specimens was performed in the laboratory. Black fungi were isolated from a specimen from a rack and had the same morphological features with Cladosporium spp. from clinical specimens. After the rack was autoclaved, Cladosporium spp. from clinical specimens was no longer isolated. CONCLUSION: Epidemiological investigation, microscopic examination, and molecular analysis revealed that the sudden increase in the isolation rate of Cladosporium spp. from clinical specimens was the result of a pseudo-outbreak caused by the contamination of a rack. To our knowledge, this is the first report of a pseudo-outbreak of Cladosporium spp. Continuous monitoring of culture results is important to avoid unnecessary labor for nosocomial infection control.
Cladosporium ; Cross Infection ; Disinfection ; Fungi ; Humans ; Infection Control ; Nails ; Sinusitis ; Skin

Among gram-negative bacteria, rate of antibiotic resistance has been increasing. As a result, carbapenem is now considered as a last resort of therapeutic regimens for gram-negative bacterial infections. The choice of antibiotics has been impeded by the spread of organisms producing metallo-beta-lactamases (MBL), which can confer resistance to nearly all beta-lactams. MBLs have extremely diverse structures and are carried by various organisms including human pathogens. This review will focus on the classification and current status of MBL reported in Korea.
Anti-Bacterial Agents ; beta-Lactams ; Drug Resistance, Microbial ; Gram-Negative Bacteria ; Gram-Negative Bacterial Infections ; Health Resorts ; Humans ; Korea

Chryseobacterium hominis is non-fermenting Gram-negative rod that was first identified as a novel species in 2007. Here, we report the first clinical case of C. hominis bacteremia, which was confirmed by MALDI-TOF MS and 16S rRNA gene sequencing. A 16-year-old boy diagnosed with acute lymphoblastic leukemia was hospitalized for three months. Two sets of blood culture test through a peripherally inserted central catheter (PICC), which was inserted a month ago, was performed when his white blood cell count declined and he had a high fever. Colonies of medium sizes that looked round, mucoid, sticky, and grayish on blood and chocolate agar plates were observed. Identification of bacteria using the VITEK MALDI-TOF MS system (BioMérieux, France) was not successful and the VITEK 2 system (BioMérieux, USA) indicated Sphingomonas paucimobilis, with a questionable level of confidence (92%). However, Microflex LT Biotyper (Bruker Daltonics, Germany) showed C. homins (log score: 1.81) and sequence of 16S rRNA showed a 100% identity with C. hominis. Piperacillin-tazobactam was administered since the isolate was susceptible to piperacillin-tazobactam but C. hominis showed growth in the next four follow-up culture of blood drawn through PICC. The fever subsided only after PICC was changed. The clinical prognosis and antimicrobial susceptibility test of C. hominis should be further studied.
Adolescent ; Agar ; Bacteremia ; Bacteria ; Cacao ; Catheters ; Chryseobacterium ; Fever ; Follow-Up Studies ; Genes, rRNA ; Humans ; Leukocyte Count ; Male ; Precursor Cell Lymphoblastic Leukemia-Lymphoma ; Prognosis ; Sphingomonas

BACKGROUND: The diagnostic significance of the serological detection of antibodies to Helicobacter pylori (H. pylori) has been reported by many investigators. But the comparison data between the various serological kits were not established in Korea. METHODS: Forty nine patients with upper gastrointestinal symptoms were studied from June 1997 to September 1997 in Yonsei University College of Medicine, Severance hospital. Endoscopic gastric biopsy specimens were obtained for microscopic examination of the bacteria and rapid urease test (CLO test). The sera of these patients were obtained for the serological test at the same time. The six commercial kits (Cobas Core II, G.A.P. test IgG, PYLORAGEN, QuickVue, BIOCARD Helicobacter pylori IgG, EZ-H.P.) for the detection H. pylori antibodies were evaluated for diagnosis and screening of H. pylori infection. RESULTS: Sensitivities for the six kits were from 71% to 96%, specificities were from 24% to 71%, positive predictive values were from 68% to 81%, negative predictive values were from 60% to 80%, respectively. There were statistically significant differences in four groups, between G.A.P. test and Cobas Core, G.A.P. test and PYLORAGEN, QuickVue and Cobas Core, QuickVue and PYLORAGEN. CONCLUSIONS: Sensitivities and specificities obtained in different studies revealed as great differences in the results with the same kits as between the results obtained with different kits in the same study. So, the serologic method alone for the diagnosis of H. pylori infection is not recommended. But in the screening of H. pylori infection, it can be used, because sensitivities and negative predictive values are relatively high.
Antibodies ; Bacteria ; Biopsy ; Diagnosis ; Helicobacter pylori* ; Helicobacter* ; Humans ; Immunoglobulin G* ; Korea ; Mass Screening ; Research Personnel ; Serologic Tests ; Urease

BACKGROUND: Sequence type 131 (ST131) O25b serogroup Escherichia coli, producing CTX-M type extended-spectrum β-lactamase (ESBL), is a major clone involved in worldwide pandemic spread in both community- and healthcare-associated infections. Recently, matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) has become a routine tool for the identification of bacteria in many laboratories. This study aimed to assess the performance of MALDI-TOF MS for the screening of ESBL-producing E. coli ST131 in a rapid, inexpensive, and simple way. METHODS: A total 26 clinical E. coli, isolated from blood between 2013 and 2014, were used. The characteristics are ST131-O25b ESBL producers (n=6), ST131-O16 ESBL producers (n=4), non-ST131 ESBL producers (n=11), and non-ST131 non-ESBL producers (n=5). Specific biomarker peaks to distinguish the ST131 clonal group from others were investigated by MicroIDSys (ASTA, South Korea) and ASTA Tinkerbell 2.0 software. RESULTS: A peak at 9,713 m/z peak is useful to screen for ST131 E. coli, regardless of serogroup O25 or O16, showing a sensitivity of 100%, specificity of 56.2%, positive predictive value of 58.8%, and negative predictive value of 100% when using a relative intensity cutoff of 15%. CONCLUSION: We can screen for ST131 E. coli using MicroIDSys (ASTA), MALDI-TOF MS in a rapid, inexpensive, and simple way. However, other confirmatory tests are needed to confirm ST131 E. coli due to the low specificity of this method.
Bacteria ; Clone Cells ; Escherichia coli* ; Escherichia* ; Mass Screening ; Mass Spectrometry* ; Methods ; Pandemics ; Sensitivity and Specificity ; Serogroup

BACKGROUND: Patients infected with vancomycin-resistant enterococci (VRE) are kept in isolation to prevent the spread of VRE in medical facilities. However, decision-making regarding isolation can be challenging at the time of re-admission of previously VRE-colonized or infected patients who have not been examined for VRE infections for a long time. This study focused on providing guidelines for isolating VRE patients based on the analysis of risk factors for prolonged carriage and reacquisition of VRE. METHODS: A retrospective review was performed on medical records of patients who were diagnosed with VRE infections at a university hospital in 2009. Durations of colonization and negative conversion of VRE were estimated by Kaplan-Meier methods. Prolonged duration of VRE infections and risk factors for reacquisition were analyzed using Cox's proportional hazard model. RESULTS: Among 220 VRE-colonized patients, 132 were cleared, and 30 reacquired after negative conversion of VRE. The median duration of colonization was 33.1 weeks, and the median clearance period was 19.4 weeks. Patients who were admitted via the emergency department and treated with glycopeptides tended to have prolonged duration of VRE colonization. Prolonged hospitalization and metronidazole therapy increased the risk of reacquisition more rapidly. CONCLUSION: Treatment with glycopeptides, metronidazole antibiotic therapy, history of admission via the emergency department, and prolonged hospitalization can affect to prolonged carriage and reacquisition of VRE. Consider carefully the release of isolation of VRE patients with these risk factors.
Colon ; Emergency Service, Hospital ; Enterococcus ; Glycopeptides ; Hospitalization ; Humans ; Medical Records ; Metronidazole ; Patient Isolation ; Proportional Hazards Models ; Retrospective Studies ; Risk Factors* ; Vancomycin Resistance

PURPOSE: Virulent gene expression in Staphylococcus aureus is controlled by regulators such as the accessory gene regulator (agr). Strains can be divided into four major agr groups (agr I-IV) on the basis of agrD and agrC polymorphisms. The purpose of this study was to define the proportion of agr I, II, and III polymorphisms and to compare the clinical characteristics between group I and non-group I polymorphisms of methicillin-resistant Staphylococcus aureus (MRSA) strains in a Korean tertiary care teaching hospital. MATERIALS AND METHODS: A total of 158 clinical isolates were evaluated by RFLPs (restriction fragment length polymorphisms). RESULTS: The mean age of the patients was 50.2 +/- 21.9 years old. There were 74 (49.3%), 66 (44.0%), 10 (6.7%), 7 (4.4%), and 1 (0.6%) strains in agr group I, II, III, I + II, and I + III polymorphisms, respectively. Only ear infections were a statistically significant clinical parameter according to univariate (p=0.001) and multivariate analysis (OR, 4.721 (1.273-17.508), p=0.020). CONCLUSION: This study suggests that agr group I is the most prevalent in Korea, and ear infections are correlated with the group I polymorphism, which is a different clinical trend from western countries. It can also be inferred that community-acquired MRSA correlates with agr group I.