Investigation of occurrence patterns of respiratory syncytial virus A and B in infected-patients from Cheonan, Korea.

BACKGROUND: Respiratory infections caused by viruses affect the lower respiratory tract; these infections are severe in patients with underlying diseases and can even lead to death. Respiratory syncytial virus (RSV), one of the causative agents of respiratory viral infections, is the most common cause of pneumonia and bronchiolitis in children and adults. METHODS: Respiratory specimens (nasopharyngeal aspirate, nasal swab, throat swab, etc.), which were sent to the Department of laboratory medicine from January 2012 to December 2018 for detection of respiratory viruses via real time reverse transcription PCR (Real time RT-PCR) were used in this study. RSV detected by real-time RT-PCR were analyzed on the basis of co-infection, sex and age of the patients, and year and month of sample collection. RESULTS: During the study period, we observed that the RSV detection rate was 12.8% (n = 1150/9010); the detection rate of RSV-A (7.1%) was higher than that of RSV-B (5.8%). The detection rate of RSV was the highest at 36.5% in December, and RSV-A and RSV-B were in vogue every year. Co-infection rate of RSVs was the highest in the patients over 80 years of age; RSVs showed the highest Co-infection with Rhinoviruses. CONCLUSIONS: During the study period, prevalence was different among the two subtypes of RSV, and the average age of RSV-B-positive patients was higher than that of RSV-A. Co-infection rate tended to increase every year. RSVs cause mild as well as severe infections. There are reports of serious clinical progress as RSVs cause overlapping infections with other viruses and increase the risk of secondary bacterial infections. Thus, further research on RSV should be done.

Epidemics of enterovirus infection in Chungnam Korea, 2008 and 2009.

Previously, we explored the epidemic pattern and molecular characterization of enteroviruses isolated in Chungnam, Korea from 2005 to 2006. The present study extended these observations to 2008 and 2009. In this study, enteroviruses showed similar seasonal prevalent pattern from summer to fall and age distribution to previous investigation. The most prevalent month was July: 42.9% in 2008 and 31.9% in 2009. The highest rate of enterovirus-positive samples occurred in children < 1-year-old-age. Enterovirus-positive samples were subjected to sequence determination of the VP1 region, which resolved the isolated enteroviruses into 10 types in 2008 (coxsackievirus A4, A16, B1, B3, echovirus 6, 7, 9, 11, 16, and 30) and 8 types in 2009 (coxsackievirus A2, A4, A5, A16, B1, B5, echovirus 11, and enterovirus 71). The most prevalent enterovirus serotype in 2008 and 2009 was echovirus 30 and coxsackievirus B1, respectively, whereas echovirus 18 and echovirus 5 were the most prevalent types in 2005 and 2006, respectively. Comparison of coxsackievirus B1 and B5 of prevalent enterovirus type in Korea in 2009 with reference strains of each same serotype were conducted to genetic analysis by a phylogenetic tree. The sequences of coxsackievirus B1 strains segregated into four distinct clusters (A, B, C, and D) with some temporal and regional sub-clustering. Most of Korean coxsackievirus B1 strains in 2008 and 2009 were in cluster D, while only "Kor08-CVB1-001CN" was cluster C. The coxsackievirus B5 strains segregated in five distinct genetic groups (clusters A-E) were supported by high bootstrap values. The Korean strains isolated in 2001 belonged to cluster D, whereas Korean strains isolated in 2005 and 2009 belonged to cluster E. Comparison of the VP1 amino acid sequences of the Korean coxsackievirus B5 isolates with reference strains revealed amino acid sequence substitutions at nine amino acid sequences (532, 562, 570, 571, 576-578, 582, 583, and 585).

Improving the Quality of Response Surface Analysis of an Experiment for Coffee-supplemented Milk Beverage: II. Heterogeneous Third-order Models and Multi-response Optimization.

This research was motivated by our encounter with the situation where an optimization was done based on statistically non-significant models having poor fits. Such a situation took place in a research to optimize manufacturing conditions for improving storage stability of coffee-supplemented milk beverage by using response surface methodology, where two responses are Y1=particle size and Y2=zeta-potential, two factors are F1=speed of primary homogenization (rpm) and F2=concentration of emulsifier (%), and the optimization objective is to simultaneously minimize Y1 and maximize Y2. For response surface analysis, practically, the second-order polynomial model is almost solely used. But, there exists the cases in which the second-order model fails to provide a good fit, to which remedies are seldom known to researchers. Thus, as an alternative to a failed second-order model, we present the heterogeneous third-order model, which can be used when the experimental plan is a two-factor central composite design having -1, 0, and 1 as the coded levels of factors. And, for multi-response optimization, we suggest a modified desirability function technique. Using these two methods, we have obtained statistical models with improved fits and multi-response optimization results with the predictions better than those in the previous research. Our predicted optimum combination of conditions is (F1, F2)=(5,000, 0.295), which is different from the previous combination. This research is expected to help improve the quality of response surface analysis in experimental sciences including food science of animal resources.

Optimizing Medium Components for the Maximum Growth of Lactobacillus plantarum JNU 2116 Using Response Surface Methodology.

This study was undertaken to find the optimum soy-peptone, glucose, yeast extract, and magnesium sulfate amounts for the maximum growth of Lactobacillus plantarum JNU 2116 and to assess the effects of these medium factors through the use of response surface methodology. A central composite design was used as the experimental design for the allocation of treatment combinations. In the analysis of the experiment, due to a significant lack of fit of the second-order polynomial regression model that was used at first, cubic terms were added to the model, and then two-way interaction terms were deleted from the model since they were found to be all statistically insignificant. A relative comparison among the four factors showed that the growth of L. plantarum JNU 2116 was affected strongly by yeast extract, moderately by glucose and peptone, and slightly by magnesium sulfate. The estimated optimum amounts of the medium factors for the growth of L. plantarum JNU 2116 are as follows: soy-peptone 0.213%, glucose 1.232%, yeast extract 1.97%, and magnesium sulfate 0.08%. These results may contribute to the production of L. plantarum L67 as a starter culture that may have potential application in yogurt and fermented meat products.

Response Surface Methodology Using a Fullest Balanced Model: A Re-Analysis of a Dataset in the Korean Journal for Food Science of Animal Resources.

Response surface methodology (RSM) is a useful set of statistical techniques for modeling and optimizing responses in research studies of food science. In the analysis of response surface data, a second-order polynomial regression model is usually used. However, sometimes we encounter situations where the fit of the second-order model is poor. If the model fitted to the data has a poor fit including a lack of fit, the modeling and optimization results might not be accurate. In such a case, using a fullest balanced model, which has no lack of fit, can fix such problem, enhancing the accuracy of the response surface modeling and optimization. This article presents how to develop and use such a model for the better modeling and optimizing of the response through an illustrative re-analysis of a dataset in Park et al. (2014) published in the Korean Journal for Food Science of Animal Resources.

Association of C-reactive protein with the metabolic risk factors among young and middle-aged Koreans.

We investigated the relationship between the clustering of risk factors for metabolic syndrome and the plasma C-reactive protein (CRP) concentration as measured by high-sensitive CRP assay. Body mass index, waist circumference, triglycerides (TGs), high-density lipoprotein cholesterol, fasting glucose, systolic and diastolic blood pressures, insulin, and CRP were measured in 1046 Korean adults (560 males; age, 18-64 years) in 2003 to 2004. There were statistically significant positive correlations for log CRP with body mass index, waist circumference, log TG, log insulin, and log homeostasis model assessment in both sexes after adjusting for age and smoking status. High-density lipoprotein cholesterol showed a significant negative correlation with log CRP in both sexes. For both sexes, the mean level of log CRP increased with increasing number of risk factors of metabolic syndrome (P for trend <.01 for males and <.001 for females). Stepwise multivariate linear regression analysis showed that waist circumference contributed the largest portion of the variance in CRP levels in both sexes. Log homeostasis model assessment and log TG were independently associated with log CRP levels only in females. These results indicate that CRP, a marker of inflammation that underlies atherosclerosis, is associated with the clustering of each metabolic syndrome risk factor and, furthermore, that abdominal obesity is the strongest predictor of CRP level in the Korean adult population.

Prevalence and clinical implications of Staphylococcus aureus with a vancomycin MIC of 4 microg/ml in Korea.

In addition to vancomycin-intermediate Staphylococcus aureus (VISA), S. aureus with a vancomycin MIC of 4 microg/ml has been reported to be the cause of therapeutic failure. This study was designed to determine the prevalence of methicillin-resistant S. aureus (MRSA) with a vancomycin MIC of 4 microg/ml and to clarify the clinical characteristics of infections caused by these isolates. During the 8-week period from April to May, 2001, 27 hospitals participated in a nationwide surveillance program for VISA and vancomycin-resistant S. aureus (VRSA) in Korea. After screening on brain-heart infusion agar containing 4 microg/ml of vancomycin as previously described, 100 isolates with confluent growth were tested. The medical records of the patients involved were reviewed. Even though VISA or VRSA was not detected among 3,756 MRSA isolates, 18 (0.5%) had a vancomycin MIC of 4 microg/ml. The infections in 12 of these patients, excluding 5 that were colonized, were 8 chronic osteomyelitis, 1 surgical site infection, 1 pneumonia, 1 intra-abdominal infection, and 1 catheter-related infection. Although 11 cases were exposed to glycopeptides for a long time (median 56 days), the site of infection became culture-negative in only 1 case. Two patients died of their S. aureus infections. MRSA with a vancomycin MIC of 4 microg/ml was rare. Chronic osteomyelitis was the most common type of infection, and prolonged exposure to glycopeptides was associated with reduced susceptibility to vancomycin.

CTX-M and SHV-12 beta-lactamases are the most common extended-spectrum enzymes in clinical isolates of Escherichia coli and Klebsiella pneumoniae collected from 3 university hospitals within Korea.

Among the 443 clinical isolates of Escherichia coli and Klebsiella spp. collected between June and November 2003 from 3 university hospitals in Korea, 62 isolates were confirmed as extended-spectrum beta-lactamase (ESBL)- or plasmid-mediated AmpC beta-lactamase-producers by double disk synergy test, PCR and sequencing for beta-lactamase genes. The most frequently identified ESBL gene among E. coli and K. pneumoniae isolates was bla(SHV-12) and bla(CTX-M) (bla(CTX-M-9), bla(CTX-M-14), bla(CTX-M-3), and bla(CTX-M-15)). Four kinds of plasmid-mediated AmpC beta-lactamases, ACT-1, CMY-1, CMY-2, and DHA-1, were detected. ESBL production was associated with high levels of resistance to tetracycline, sulfisoxazole, streptomycin, kanamycin, gentamicin and tobramycin when compared to non-ESBL producing isolates. Conclusively, this study suggests that the CTX-M beta-lactamases are prevalent and various kinds of plasmid-mediated AmpC enzymes are distributed in clinical isolates of E. coli and Klebsiella spp. in Korea.

Identification and distribution of nontuberculous mycobacteria from 2005 to 2011 in cheonan, Korea.

BACKGROUND: Nontuberculous mycobacteria (NTM) are considered opportunistic pathogens, and several species of NTM are associated with human diseases that typically involve the pulmonary, skin/soft tissue, or lymphatic systems; such infection may also cause disseminated diseases. Recent studies have reported increasing rates of NTM-induced disease worldwide. METHODS: Respiratory samples are being analyzed for acid-fast bacilli (AFB) culture and NTM identification at Dankook University Hospital in Cheonan, Korea, from September 2005 to September 2011. Identification is performed by using polymerase chain reaction-restriction fragment length polymorphism analysis targeting a novel region of the rpoB gene. RESULTS: A total of 25,133 specimens were received for AFB culture, of which 1,014 (4.0%) were NTM-positive. A total of 267 samples from 186 patients were tested for NTM identifications, and 232 samples from 157 patients were positive for NTM species. Among the patients who tested positive for NTM, 65.6% were men and the average age was 63.3 years. Mycobacterium avium complex, the most commonly detected NTM pathogen, was found in 65.9% of the 232 samples. The annual average percentage of NTM isolates from AFB culture-positive specimens was 31.3%: the highest rate was seen in 2011 (44.3%), followed by 2009 (37.4%) and 2010 (37.2%). An upward trend in NTM incidence was found during the study period. CONCLUSION: The prevalence of pulmonary NTM isolates continues to increase in Cheonan, suggesting that pulmonary NTM disease is becoming increasingly common.

Epidemiology of respiratory viral infection using multiplex rt-PCR in Cheonan, Korea (2006-2010).

Multiplex RT-PCR was used to detect respiratory viruses in 5,318 clinical samples referred to the laboratory of a tertiary teaching hospital from December 2006 to November 2010. The acquired data were analyzed with respect to types, ratio, and co-infection trends of infected respiratory viruses. Trends in respiratory viral infection according to sex, age, and period of infection were also analyzed. Of the 5,318 submitted clinical samples, 3,350 (63.0%) specimens were positive for at least one respiratory virus. The infection rates were 15.8% for human rhinovirus, 14.4% for human respiratory syncytial virus A, 9.7% for human respiratory syncytial virus B, 10.1% for human adenovirus, 5.4% for influenza A virus, 1.7% for influenza B virus, 4.7% for human metapneumovirus, 2.3% for human coronavirus OC43, 1.9% for human coronavirus 229E/NL63, 3.7% for human parainfluenza virus (HPIV)-1, 1.1% for HPIV-2, and 5.3% for HPIV-3. The co-infection analysis showed 17.1% of double infections and 1.8% of triple infections. The median age of virus-positive patients was 1.3 years, and 91.5% of virus-positive patients were under 10 years old. Human respiratory syncytial virus was the most common virus in children under 5 years of age, and the influenza A virus was the most prevalent virus in children over 5 years of age. These results help in elucidating the tendency of respiratory viral infections.

Current routine practice and clinico-pathological characteristics associated with acute promyelocytic leukemia in Korea.

BACKGROUND: Acute promyelocytic leukemia (APL) can be life threatening, necessitating emergency therapy with prompt diagnosis by morphologic findings, immunophenotyping, cytogenetic analysis, or molecular studies. This study aimed to assess the current routine practices in APL and the clinico-pathologic features of APL. METHODS: We reviewed the medical records of 48 Korean patients (25 men, 23 women; median age, 51 (20-80) years) diagnosed with APL in 5 university hospitals between March 2007 and February 2012. RESULTS: The WBC count at diagnosis and platelet count varied from 0.4 to 81.0 (median 2.0)×10(9)/L and 2.7 to 124.0 (median 54.5)×10(9)/L, respectively. The median values for prothrombin time and activated partial thromboplastin time were 14.7 (11.3-44.1) s and 29 (24-62) s, respectively. All but 2 patients (96%) showed a fibrin/fibrinogen degradation product value of >20 µg/mL. The D-dimer median value was 5,000 (686-55,630) ng/mL. The t(15;17)(q22;q12 and PML-RARA fusion was found in all patients by chromosome analysis and/or multiplex reverse transcriptase-polymerase chain reaction (RT-PCR), with turnaround times of 8 (2-19) d and 7 (2-13) d, respectively. All patients received induction chemotherapy: all-trans retinoic acid (ATRA) alone (N=11, 26%), ATRA+idarubicin (N=25, 58%), ATRA+cytarabine (N=3, 7%), ATRA+idarubicin+cytarabine (N=4, 9%). CONCLUSION: Since APL is a medical emergency and an accurate diagnosis is a prerequisite for prompt treatment, laboratory support to implement faster diagnostic tools to confirm the presence of PML-RARA is required.

Evaluation of a multiplex real-time PCR assay for the detection of respiratory viruses in clinical specimens.

BACKGROUND: In this study, we evaluated the analytical performance and clinical potential of a one-step multiplex real-time PCR assay for the simultaneous detection of 14 types of respiratory viruses using the AdvanSure RV real-time PCR Kit (LG Life Sciences, Korea). METHODS: Three hundred and twenty clinical specimens were tested with the AdvanSure RV real-time PCR Kit and conventional multiplex reverse transcription (RT)-PCR assay. The assay results were analyzed and the one-step AdvanSure RV real-time PCR Kit was compared with the conventional multiplex RT-PCR assay with respect to the sensitivity and specificity of the detection of respiratory viruses. RESULTS: The limit of detection (LOD) was 1.31 plaque-forming units (PFU)/mL for human rhinoviruses (hRVs), 4.93 PFU/mL for human coronavirus HCoV-229E/NL63, 2.67 PFU/mL for human coronavirus HCoV-OC43, 18.20 PFU/mL for parainfluenza virus 1 (PIV)-1, 24.57 PFU/mL for PIV-2, 1.73 PFU/mL for PIV-3, 1.79 PFU/mL for influenza virus group (Flu) A, 59.51 PFU/mL for FluB, 5.46 PFU/mL for human respiratory syncytial virus (hRSV)-A, 17.23 PFU/mL for hRSV-B, 9.99 PFU/mL for human adenovirus (ADVs). The cross-reactivity test for this assay against 23 types of non-respiratory viruses showed negative results for all viruses tested. The agreement between the one-step AdvanSure multiplex real-time PCR assay and the conventional multiplex RT-PCR assay was 98%. CONCLUSIONS: The one-step AdvanSure RV multiplex real-time PCR assay is a simple assay with high potential for specific, rapid and sensitive laboratory diagnosis of respiratory viruses compared to conventional multiplex RT-PCR.

[Evaluation of Seeplex Pneumobacter multiplex PCR kit for the detection of respiratory bacterial pathogens in pediatric patients].

BACKGROUND: Rapid identification of the causative agent among potential bacterial and viral pathogens is important for the management of acute respiratory disease. In this study, we evaluated the analytical performance and clinical usefulness of a recently-introduced multiplex PCR assay, Seeplex Pneumobacter detection kit (Seegene Inc., Korea) for the identification of respiratory bacterial pathogens. METHODS: One hundred and eighty one nasopharyngeal aspirates were collected from pediatric patients with respiratory symptoms and analysed by multiplex PCR for the detection of Streptococcus pneumoniae (S.P), Haemophilus influenzae (H.I), Mycoplasma pneumoniae (M.P), Chlamydophila pneumoniae (C.P), Bordetella pertussis (B.P) and Legionella pneumophila (L.P). A comparison of multiplex PCR with conventional culture for the isolation of S.P and H.I was performed on 112 specimens. The cross reactivity of multiplex PCR was also evaluated. RESULTS: Of 181 cases, 81 cases were positive by multiplex PCR (44.8%): 52 cases for S.P (28.7%), 47 cases for H.I (26.0%), 9 cases for M.P (5.0%), 3 cases for B.P (1.7%) and 1 case for C.P (0.6%) including multiple infection cases. The agreement rates between multiplex PCR and culture for S.P and H.I were 92.9% (kappa index=0.84, P<0.001) and 91.1% (kappa index=0.75, P<0.001), respectively. There was no cross reactivity with common bacterial and viral pathogens. CONCLUSIONS: Seeplex Pneumobacter detection kit could be a useful screening tool for the rapid detection of respiratory bacterial pathogens. Further studies with lower respiratory tract specimens would be needed for the clinical evaluation of S. pneumoniae and H. influenzae detected by multiplex PCR.

No differences of carotid intima-media thickness between young patients with ankylosing spondylitis and healthy controls.

OBJECTIVE: Accelerated atherosclerosis in inflammatory rheumatic diseases such as ankylosing spondylitis (AS) stands out among the leading causes of morbidity and mortality. We assessed the correlation between subclinical carotid atherosclerosis and its related clinical parameters in AS patients. METHODS: Twenty-eight patients (23 males, 5 females) with AS and 27 sex- and age-matched controls were consecutively recruited to this study. We estimated the carotid intima-media thickness (IMT) and parameters related to arterial elastic properties, including the distensibility coefficient (DC), stiffness index (beta), and incremental elastic modulus (E(inc)) using high-resolution ultrasonography. Serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and monocyte chemoattractant protein-1 (MCP-1) were measured using enzyme-linked immunosorbent assay (ELISA). RESULTS: Carotid IMT values and arterial elastic parameters in AS patients showed no statistical significance compared to those of controls (0.57+/-0.07 vs 0.55+/-0.05, p=0.387 for IMT, 28.45+/-9.23 vs 31.93+/-9.52, p=0.175 for DC, 2.32+/-0.18 vs 2.29+/-0.15, p=0.559 for stiffness index (beta), and 0.14+/-0.05 vs 0.12+/-0.03, p=0.116 for E(inc)). The serum level of IL-6 in AS patients was significantly different compared with controls (p=0.001), but not in serum levels of TNF-alpha and MCP-1 (p=0.162, p=0.087, respectively). Carotid IMT and all arterial elastic parameters calculated in this study were not found to be associated with serum levels of TNF-alpha, IL-6, and MCP-1. CONCLUSION: This cross-sectional study showed that carotid IMT and parameters related with arterial elastic properties in young AS patients without clinically evident cardiovascular risk factors were not different from those of sex- and age-matched healthy controls. Serum levels of TNF-alpha, IL-6, and MCP-1 did not reflect the degree of carotid subclinical atherosclerosis. However, these findings should be confirmed further in a larger population.