BACKGROUND: This study analysed patterns of requests for repeated blood cultures and the microorganisms isolated in follow-up cultures. METHODS: The frequencies and intervals of repeated blood cultures performed during January and February of 2010 at seven university-affiliated hospitals in Korea were evaluated. Results of microbiological cultures at follow-up were analysed with respect to pathogen replication, immune clearance, appearance of new pathogens, and skin contaminants. RESULTS: Among 3,072 patients who received repeated blood cultures, the average number of requests was 3.2. Of the 5,241 follow-up blood culture events recorded, durations of 1, 2, and 3 days between cultures were identified for 23.1%, 21.4%, and 15.0% of events, respectively. Relative to each initial culture, persistent pathogen growth in subsequent culture(s) accounted for 2.3% of events, whereas immune clearance was confirmed in 8.5% of events. Previously undetected pathogens were isolated in 5.2% of the follow-up cultures, the majority of which grew after an interval of six days. Skin contaminants were detected in 7.6% of the repeated cultures, and 76.1% of the follow-ups displayed no growth of microorganisms. CONCLUSION: The most common numbers of repeat culture requests were two and three, and these were typically performed within three days of the initial culture. Among the follow-up cultures, new pathogens were identified in 5.2%, and the majority of this group likely presented for follow-up during a new disease episode.
Follow-Up Studies ; Humans ; Korea ; Sepsis ; Skin

BACKGROUND: We analyzed the prevalence of anti-tuberculosis drug resistance in Mycobacterium tuberculosis isolates from respiratory specimens of patients with newly diagnosed and previously treated tuberculosis. METHODS: From February 2010 to July 2010, a total of 542 M. tuberculosis clinical isolates were collected from pulmonary tuberculosis patients in six university hospitals distributed throughout Korea. We analyzed the results of anti-tuberculosis drug resistance tests according to treatment history and geographic location. RESULTS: Among the 542 isolates, 473 (87.3%) were from newly diagnosed cases and 69 (12.7%) were from previously treated cases. The rates of multi-drug resistance (MDR), fluoroquinolone (ofloxacin, levofloxacin, and moxifloxacin) resistance, and extensive drug resistance (XDR) were 3.8%, 1.1-1.5%, and 0%, respectively, in new cases, and 21.7%, 13.0-17.4%, and 4.3%, respectively, in previously treated cases. In the previously treated cases, the proportions of XDR-TB in MDR-TB were 20% (3/15). The resistance rates were variable according to geographic location. CONCLUSION: As the anti-tuberculosis drug resistance rates are much higher in newly diagnosed cases than in previously treated patients, efforts should be made to ensure that tuberculosis treatment is successful. In addition, before the selection of an anti-tuberculosis drug treatment for previously treated patients, the susceptibility test results, including to fluoroquinolone, should be verified.
Dietary Sucrose ; Drug Resistance ; Drug Resistance, Multiple ; Extensively Drug-Resistant Tuberculosis ; Hospitals, University ; Humans ; Korea ; Mycobacterium ; Mycobacterium tuberculosis ; Ofloxacin ; Prevalence ; Tuberculosis ; Tuberculosis, Pulmonary

Brevibacterium spp. are Gram-positive, irregularly rod-shaped, strictly aerobic bacteria that resemble corynebacteria. Since they are a part of normal skin flora, they have been regarded as apathogenic, and human infections related to them are very rare. A 46-year-old man previously diagnosed with diffuse large B-cell lymphoma presented with fever without a definitive infectious source. Blood cultures from both peripheral blood and a central venous catheter showed that only aerobic bottles grew contaminants, while anaerobic bottles did not. Although the automated microbial identification system indicated Propionibacterium acnes, the isolated species was identified as B. casei by 16S rRNA sequence analysis. Our case emphasizes the utilization of 16S rRNA sequence analysis when the result from an automated system does not correspond with other laboratory findings. This is the first case of catheter-related blood stream infection due to B. casei identified by 16S rRNA sequence analysis.
Bacteria, Aerobic ; Brevibacterium* ; Central Venous Catheters ; Fever ; Humans ; Lymphoma* ; Lymphoma, B-Cell ; Middle Aged ; Propionibacterium acnes* ; Rivers ; Sequence Analysis ; Skin

Toxic shock syndrome is an acute and febrile illness that rapidly progress to shock and multi-organ failure, and it is caused by toxin-producing strains of Staphylococcus aureus or Streptococcus species. Streptococcal toxic shock syndrome (STSS) is usually caused by group A streptococci, but non-group A STSS is rare. In this study, we describe a case of STSS caused by Streptococcus agalactiae(group B streptococci) in a patient with alcoholic liver cirrhosis. At arrival in our hospital, the patient had a decreased mental status with hemorrhagic bullae on four extremities, and he progressed to a fatal outcome within 4 days in spite of antibiotic treatment.
Extremities ; Fatal Outcome ; Humans ; Liver Cirrhosis ; Liver Cirrhosis, Alcoholic ; Shock ; Shock, Septic ; Staphylococcus aureus ; Streptococcus ; Streptococcus agalactiae

Multiplex PCR of nasopharyngeal aspirates detected viruses and atypical bacteria in 75.3% (219/291) of infants with acute respiratory infections from July 2010 to June 2013. Frequent viruses were human rhinovirus (29.9%), parainfluenza virus (21.7%), respiratory syncytial virus (17.9%), and human metapneumovirus (10.3%). Mycoplasma pneumoniae and Bordetella pertussis were detected in 3.4% and 0.3%, respectively.
Bacteria ; Bordetella pertussis ; Humans ; Infant* ; Metapneumovirus ; Multiplex Polymerase Chain Reaction* ; Mycoplasma pneumoniae ; Paramyxoviridae Infections ; Pneumonia, Mycoplasma ; Respiratory Syncytial Viruses ; Respiratory Tract Infections* ; Rhinovirus

BACKGROUND: Fluoroquinolones (FQs) are important drugs for treating multidrug-resistant tuberculosis (MDR-TB). However, due to widespread use of FQs, the resistance rates to FQs have been increasing among Mycobacterium tuberculosis. Rapid and reliable FQ drug susceptibility testing (DST) is crucial for successful treatment of MDR-TB. In this study, the feasibility of molecular detection of FQ resistance was evaluated. METHODS: A total of 95 MDR-TB isolates were collected from Jan through Oct 2009 at the Korean Institute of Tuberculosis. DST for ofloxacin (OFL), levofloxacin, and moxifloxacin was performed using the Lowenstein-Jensen media absolute concentration method. Minimum inhibitory concentrations (MIC) of these were determined using the broth microdilution method. DNA was extracted from cultured isolates using bead beating method. The quinolone resistance-determining region (QRDR) of gyrA and gyrB were amplified and those sequences were analyzed. RESULTS: Of 95 isolates, 79 were resistant to at least one of FQs. Of these, 71 (89.9%) harbored mutation in the QRDR of gyrA or gyrB. None of FQ susceptible strains possessed any mutation in gyrA or gyrB. Mutations in codon 94 of gyrA were most common; only two isolates had mutation in only the gyrB gene. OFL MICs for isolates with gyrA mutation ranged from 1 to 32 microg/mL, but FQ susceptible isolates showed MICs ranging from < or =0.06 to 0.5 microg/mL. CONCLUSION: Mutation analysis of QRDR of gyrA and gyrB showed 89.9% sensitivity and 100% specificity for detecting FQ resistance in MDR-TB. Therefore, molecular DST can be useful for rapid detection of FQ resistance in MDR-TB.
Codon ; DNA ; Fluoroquinolones ; Levofloxacin ; Microbial Sensitivity Tests ; Mycobacterium tuberculosis* ; Ofloxacin ; Tuberculosis ; Tuberculosis, Multidrug-Resistant

BACKGROUND: The intestinal microflora varies according to the factors such as age, diet and environment. It is debated whether the changes of microbiota after birth are associated with atopic disease. The purpose of this study was to investigate colonization rates of some intestinal microflora during the initial 9 months after birth, and their association with the development of atopy. METHODS: Stool specimens were collected at 1, 3, 7 days and at 1, 2, 4, 6, 9 months after birth, and Escherichia coli, Lactobacillus, Bifidobacterium, Staphylococcus aureus were cultured with selective media. Diagnosis for atopy was accomplished via clinical history of atopy, serum total IgE, and skin prick test. RESULTS: By 12 months of age, among 48 infants, 36 (75.0%) were non-atopic while 12 (25.0%) had developed atopy. Although not statistically significant, the intestinal microflora of infants with atopy vs. non-atopy was characterized by being less often colonized with E. coli (12.5% vs. 52.4%; P=0.093) and S. aureus (0% vs. 38.1%; P=0.066) at three days after birth. Colonization rates of E. coli reached 50% after 3 days of birth in non-atopy group whereas this rate was not achieved until after 1 month in the atopy group. CONCLUSION: The intestinal colonization rates of bacteria in this study were not statistically different between atopy and non-atopy groups. Rapid colonization of E. coli and S. aureus was observed within 1 week after birth in the non-atopy group. The exact association between atopy and the bacterial colonization and/or diversity in the early days after birth has yet to be determined.
Bacteria ; Bifidobacterium ; Colon ; Diagnosis ; Diet ; Escherichia coli ; Humans ; Immunoglobulin E ; Infant* ; Lactobacillus ; Microbiota ; Parturition ; Skin ; Staphylococcus aureus

BACKGROUND: In this study, we compared various methods of taxonomic identification of Bacillus strains: biochemical methods, 16S rRNA gene sequencing, and matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). We also developed a pathogen- isolate resource database, thus increasing the identification rate when using MALDI-TOF MS. METHODS: Thirty Bacillus strains were obtained from the NCCP (National Culture Collection for Pathogens) and were identified using the VITEK 2 system (bio-Mérieux, France), API kit (bioMérieux, France), 16S rRNA gene sequencing, and MALDI-TOF MS. The pathogenicity of Bacillus cereus was confirmed through the identification of virulent genes using a multiplex PCR, and both protein extraction for protein profiling in MALDI-TOF MS and repetitive-sequence fingerprinting were performed. RESULTS: The identification rates at the species level were 40%, 80%, and 76.3% for the VITEK 2 system (bioMérieux), 16S rRNA gene sequencing, and MALDI-TOF MS, respectively. When the major spectrum-profiling dendrogram was compared with the phylogenetic tree, which was constructed based on the 16S rRNA gene sequences and rep-PCR fingerprinting, the classifications were confirmed to be effective. CONCLUSION: Identification of Bacillus strains using MALDI-TOF MS was more effective than that using the VITEK 2 system (bioMérieux), but was similar to that using 16S rRNA gene sequencing. Continual addition to a proteome-based database can result in increased identification rates for MALDI-TOF MS.
Bacillus cereus ; Bacillus* ; Classification ; Dermatoglyphics ; Genes, rRNA ; Mass Spectrometry* ; Multiplex Polymerase Chain Reaction ; Trees ; Virulence

BACKGROUND: The spectrum of bacteria causing diarrhea is highly affected by geographic area, sanitation, travel, food consumption, and previous antibiotic use. A nationwide databank for stool cultures is undeveloped. The aim of our study was to investigate the current prevalence of gastroenteritis bacterial pathogens in Korea. METHODS: We requested microbiological data via questionnaire emails sent to 98 hospitals. The frequency of each pathogen was acquired from 32 institutes. Numbers of stool cultures performed ranged from 193 to 14,296 (mean 2,724, SD 3,261) in 2015. RESULTS: Among 86,744 requested stool specimens, 917 (1.06%, range 0-4.59%, 95% confidence interval 0.63-1.48%) were positive. Salmonella was most prevalent (59.0%), followed by Candida (12.4%), Campylobacter (4.8%), Staphylococcus aureus (4.0%), Vibrio (4.0%), and Pseudomonas aeruginosa (1.75). Yersinia (0.3%) and Shigella (0.2%) were rarely isolated. CONCLUSION: As the positive rate of the stool cultures is very low (1.06%), more effort and concern should be provided to enhance the isolation of pathogens. Salmonella was the most prevalent pathogen and Campylobacter and Vibrio were relatively common pathogens causing bacterial gastroenteritis in Korea.
Academies and Institutes ; Bacteria* ; Campylobacter ; Candida ; Diarrhea ; Electronic Mail ; Gastroenteritis ; Korea* ; Prevalence* ; Pseudomonas aeruginosa ; Salmonella ; Sanitation ; Shigella ; Staphylococcus aureus ; Vibrio ; Yersinia

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