Rinovirus y metapneumovirus en pacientes con infección respiratoria aguda grave / Rhinovirus and metapneumovirus in patients with severe acute respiratory infection

Introducción. Los virus son los principales agentes etiológicos en las infecciones respiratorias agudas graves; un alto porcentaje queda sin diagnóstico viral. Objetivo. Describir la frecuencia de rinovirus y metapneumovirus en pacientes pediátricos de una unidad centinela de Mar del Plata con infección respiratoria aguda grave y resultado negativo para virus clásicos por inmunofluorescencia y biología molecular. Población y métodos. Se realizó un estudio descriptivo de corte transversal. Se evaluó la presencia de rinovirus y metapneumovirus por biología molecular en 163 casos negativos para panel respiratorio por técnicas de vigilancia referencial, durante todo el año 2015. Resultados. Se detectó rinovirus en el 51,5 % de los casos, metapneumovirus en el 9,8 % y coinfección rinovirus-metapneumovirus en el 6,1 %. Fueron negativos para ambos virus el 32,5 %. Conclusiones. La selección de muestras sin diagnóstico virológico permitió identificar rinovirus y metapneumovirus como agentes causales de infecciones respiratorias agudas graves pediátricas y su impacto en la morbimortalidad infantil y en nuestro sistema sanitario.

Introduction. Viruses are the main etiologic agents involved in severe acute respiratory tract infections; a viral diagnosis is not established in a high percentage of cases. Objective. To describe the frequency of rhinovirus and metapneumovirus in pediatric patients with severe acute respiratory infection and negative results for typical viruses by immunofluorescence and molecular biology at a sentinel unit of Mar del Plata. Population and methods. This was a descriptive, cross-sectional study. The presence of rhinovirus and metapneumovirus was assessed by molecular biology in 163 cases negative for respiratory panel by referral surveillance techniques throughout 2015. Results. Rhinovirus was detected in 51.5% of cases, metapneumovirus in 9.8%, and coinfection with rhinovirus and metapneumovirus in 6.1%. Results were negative for both viruses in 32.5%. Conclusions. The selection of samples without a viral diagnosis allowed us to identify rhinovirus and metapneumovirus as causative agents of severe acute respiratory infections in children and assess their impact on child morbidity and mortality and on our health care system

Analysis of the clinical features and the risk factors of severe human metapneu movirus-associated community acquired pneumonia in children / 中华儿科杂志

Objective: To investigate the clinical characteristics and the risk factors of severe human metapneumovirus (hMPV)-associated community acquired pneumonia (CAP) in children. Methods: A retrospective case summary was conducted. From December 2020 to March 2022, 721 children who were diagnosed with CAP and tested positive for hMPV nucleic acid by PCR-capillary electrophoresis fragment analysis of nasopharyngeal secretions at the Yuying Children's Hospital, the Second Affiliated Hospital of Wenzhou Medical University were selected as the research objects. The clinical characteristics, epidemiological characteristics and mixed pathogens of the two groups were analyzed. According to CAP diagnostic criteria, the children were divided into the severe group and the mild group. Chi-square test or Mann-Whitney rank and contrast analysis was used for comparison between groups, while multivariate Logistic regression was applied to analyze the risk factors of the severe hMPV-associated CAP. Results: A total of 721 children who were diagnosed with hMPV-associated CAP were included in this study, with 397 males and 324 females. There were 154 cases in the severe group. The age of onset was 1.0 (0.9, 3.0) years, <3 years old 104 cases (67.5%), and the length of hospital stay was 7 (6, 9) days. In the severe group, 67 children (43.5%) were complicated with underlying diseases. In the severe group, 154 cases (100.0%) had cough, 148 cases (96.1%) had shortness of breath and pulmonary moist rales, and 132 cases (85.7%) had fever, 23 cases (14.9%) were complicated with respiratory failure. C-reactive protein (CRP) was elevated in 86 children (55.8%), including CRP≥50 mg/L in 33 children (21.4%). Co-infection was detected in 77 cases (50.0%) and 102 strains of pathogen were detected, 25 strains of rhinovirus, 17 strains of Mycoplasma pneumoniae, 15 strains of Streptococcus pneumoniae, 12 strains of Haemophilus influenzae and 10 strains of respiratory syncytial virus were detected. Six cases (3.9%) received heated and humidified high flow nasal cannula oxygen therapy, 15 cases (9.7%) were admitted to intensive care unit, and 2 cases (1.3%) received mechanical ventilation. In the severe group, 108 children were cured, 42 children were improved, 4 chlidren were discharged automatically without recovery and no death occurred. There were 567 cases in the mild group. The age of onset was 2.7 (1.0, 4.0) years, and the length of hospital stay was 4 (4, 6) days.Compared with the mild group, the proportion of children who age of disease onset <6 months, CRP≥50 mg/L, the proportions of preterm birth, congenital heart disease, malnutrition, congenital airway malformation, neuromuscular disease, mixed respiratory syncytial viruses infection were higher (20 cases (13.0%) vs. 31 cases (5.5%), 32 cases (20.8%) vs. 64 cases (11.3%), 23 cases (14.9%) vs. 44 cases (7.8%), 11 cases (7.1%) vs. 18 cases (3.2%), 9 cases (5.8%) vs. 6 cases (1.1%), 11 cases (7.1%) vs. 12 cases (2.1%), 8 cases (5.2%) vs. 4 cases (0.7%), 10 cases (6.5%) vs. 13 cases (2.3%), χ2=0.42, 9.45, 7.40, 4.94, 11.40, 8.35, 3.52, 6.92, all P<0.05). Multivariate Logistic regression analysis showed that age<6 months (OR=2.51, 95%CI 1.29-4.89), CRP≥50 mg/L (OR=2.20, 95%CI 1.36-3.57), prematurity (OR=2.19, 95%CI 1.26-3.81), malnutrition (OR=6.05, 95%CI 1.89-19.39) were the independent risk factors for severe hMPV-associated CAP. Conclusions: Severe hMPV-associated CAP is most likely to occur in infants under 3 years old and has a higher proportion of underlying diseases and co-infection. The main clinical manifestations are cough, shortness of breath and pulmonary moist rales, fever. The overall prognosis is good. Age<6 months, CRP≥50 mg/L, preterm birth, malnutrition are the independent risk factors for severe hMPV-associated CAP.

Several Common Respiratory Viral Pathogens in Hematopoietic Stem Cell Transplantion Patients with Primary Immunodeficiency Disease / 中国实验血液学杂志

OBJECTIVE@#To investigate the prevalence of respiratory viral infections in patients with primary immunodeficiency disease (PID) during hematopoietic stem cell transplantation.@*METHODS@#108 specimens of nasopharyngeal aspirate were collected from 22 PID patients before and after hematopoietic stem cell transplantation from July 2016 to July 2018 in the Department of Hematology. The TR-PCR was used to detect for respiratory viruses including respiratory syncytial virus(RSV)，human metapneumoviros(hMPV)，coronavirus(CoV) and parainfluenza 1-3 (PIV1-3). And the clinical characteristics and co-infection were analyzed.@*RESULTS@#Among the total 108 specimens, viral pathogens were identified in 41 (37.96%) specimens. Among which the pathogens of highest detection rate was RSV (25.9%). Different types of PID showed different virus infection rates, among which the highest infection rate was severe combined immunodeficiency disease (SCID) patients, with the virus detection rate was 57.9%. The incidence of co-infection with two or more than two viruses was 19.5%.@*CONCLUSION@#Patients with PID who undergo hematopoietic stem cell transplantation are more susceptible to respiratory viruses. RSV is an important respiratory tract virus pathogen after hematopoietic stem cell transplantation.

Detection of avian metapneumovirus subtype A from wild birds in the State of São Paulo, Brazil / Detecção de metapneumovirus aviário subtipo A em aves silvestres no estado de São Paulo, Brasil

The present study investigated the circulation of avian metapneumovirus (aMPV) in wild birds in Brazil. To do so, 131 samples from 366 oropharyngeal or cloacal swabs collected from 18 species of birds were tested individually or in pools by RT-PCR. Samples detected by RT-PCR were selected for DNA sequencing. Thirteen (9.9%) samples were detected by the RT-PCR targeting the N gene and four out of 13 samples were sequenced. Sequencing results showed a high identity with the aMPV subtype A. Our results confirm the circulation of the aMPV subtype A in wild birds in Brazil even five years after its last detection.(AU)

O presente estudo investigou a circulação de metapneumovírus aviário em aves silvestres no Brasil. Para tanto, 131 amostras de 366 suabes orofaringeanos ou cloacais coletados de 18 espécies de aves foram testadas individualmente ou na forma de pools por RT-PCR. As amostras detectadas por RT-PCR foram selecionadas para sequenciamento. Treze (9,9%) das amostras foram detectadas por RT-PCR tendo o gene N como alvo; destas, quatro foram sequenciadas com sucesso. Resultados do sequenciamento mostraram alta identidade com o aMPV de subtipo A. Nossos resultados confirmam a circulação de aMPV subtipo A em aves silvestres no Brasil mesmo cinco anos após sua última detecção.(AU)

Influence of Fine Particulate Dust Particulate Matter 10 on Respiratory Virus Infection in the Republic of Korea

BACKGROUND: This study investigated the effect of fine dust concentrations in the air on the incidence of viral respiratory infections in the Republic of Korea.METHODS: A time series analysis using R statistics was performed to determine the relationship between weekly concentrations of fine dust in the air and the incidences of acute respiratory tract infections caused by the respiratory syncytial virus (RSV), adenovirus (HAdV), rhinovirus (HRV), human metapneumovirus (HMPV), human coronavirus (HCoV), human bocavirus (HBoV), human parainfluenza virus (HPIV), and influenza virus (IFV), from the beginning of 2016 to the end of 2017. Correlations between various meteorological factors and the amount of fine dust were analyzed using the Spearman's rank correlation coefficient. To analyze the relationship between viral infections and fine dust, a quasi-poisson analysis was performed.RESULTS: The incidence of the HAdV was proportional to fine dust and air temperature. The IFV was proportional to fine dust and relative humidity and was inversely proportional to temperature. The HMPV was proportional to fine dust, wind speed, and inversely proportional to relative humidity. The HCoV was proportional to micro dust, relative humidity, and inversely proportional to temperature. Both the HBoV and HPIV were directly proportional to fine dust, temperature, wind speed, and inversely proportional to relative humidity. The RSV was inversely proportional to fine dust, temperature, wind speed. A lag effect was observed for the influenza virus, in that its incidence increased 2–3 weeks later on the cumulative lag model.CONCLUSION: As the weekly average concentration of fine dust increases, the incidence of HAdV, HMPV, HCoV, HBoV, HPIV, and influenza increase.

Bacterial and Viral Identification Rate in Acute Exacerbation of Chronic Obstructive Pulmonary Disease in Korea

PURPOSE: The most common cause of acute exacerbation of chronic obstructive pulmonary disease (AECOPD) is respiratory infection. Most studies of bacterial or viral cause in AECOPD have been conducted in Western countries. We investigated bacterial and viral identification rates in AECOPD in Korea. MATERIALS AND METHODS: We reviewed and analyzed medical records of 736 cases of AECOPD at the Korea University Guro Hospital. We analyzed bacterial and viral identification rates and classified infections according to epidemiological factors, such as Global Initiative for Chronic Obstructive Lung Disease stage, mortality, and seasonal variation. RESULTS: The numbers of AECOPD events involving only bacterial identification, only viral identification, bacterial-viral co-identification, and no identification were 200 (27.2%), 159 (21.6%), 107 (14.5%), and 270 (36.7%), respectively. The most common infectious bacteria identified were Pseudomonas aeruginosa (13.0%), Streptococcus pneumoniae (11.4%), and Haemophilus influenzae (5.3%); the most common viruses identified were influenza virus (12.4%), rhinovirus (9.4%), parainfluenza virus (5.2%), and metapneumovirus (4.9%). The bacterial identification rate tended to be higher at more advanced stages of chronic obstructive pulmonary disease (p=0.020 overall, p=0.011 for P. aeruginosa, p=0.048 for S. pneumoniae). Staphylococcus aureus and Klebsiella pneumoniae were identified more in mortality group (p=0.003 for S. aureus, p=0.009 for K. pneumoniae). All viruses were seasonal (i.e., greater prevalence in a particular season; p < 0.050). Influenza virus and rhinovirus were mainly identified in the winter, parainfluenza virus in the summer, and metapneumovirus in the spring. CONCLUSION: This information on the epidemiology of respiratory infections in AECOPD will improve the management of AECOPD using antibiotics and other treatments in Korea.

Viral etiology of acute respiratory infections in children in Southern Iran

Abstract INTRODUCTION: Prevalence of influenza A virus (Flu-A), respiratory syncytial virus (RSV), and human metapneumovirus (hMPV) was assessed in children with acute respiratory infections (ARIs). METHODS: Nasopharyngeal aspirates and throat swabs were subjected to real-time polymerase chain reaction (PCR) to detect RSV and Flu-A and to conventional PCR to detect hMPV. RESULTS: Of the 156 children assessed, 93 (59.6%) carried at least one virus, with 35.9% positive for RSV, 14.1% for hMPV, and 9.6% for Flu-A. The prevalence of co-infections was 2.6%. CONCLUSIONS: The high detection rate may reflect increased sensitivity of real-time PCR compared to traditional PCR and viral culture.

Human metapneumovirus in Southern Brazil

INTRODUCTION Infections caused by respiratory viruses are important problems worldwide, especially in children. Human metapneumovirus (hMPV) is a respiratory pathogen and causes severe infections with nonspecific symptoms. This study reports the hMPV occurrence and dissemination in southern Brazil and compares the frequency of occurrence of this virus and the human respiratory syncytial virus (hRSV) in the epidemiological weeks in a three-year period (2009-2011). METHODS: In total, 545 nasopharyngeal (NP) specimens from individuals with Severe Acute Respiratory Syndrome (SARS) who were negative for other seven respiratory viruses were analyzed for the presence of hMPV. Human metapneumovirus was detected by direct immunofluorescence and real-time reverse transcription polymerase chain reaction. RESULTS: hMPV was detected in 109 patients from the main geographic regions of the southernmost state of Brazil, presenting similar overall prevalence in males (46.8%) and females (53.2%). Among children who were less than six years old, hMPV was detected in 99 samples of all age groups, with a higher frequency in infants who were less than one year old (45.7%) compared to all other age groups until six years. hMPV and hRSV infection occurred in almost the same epidemiological weeks (EWs) of each year, with peaks of incidence between EW 31/37 and EW 26/38 for the years 2009 and 2011, respectively. hMPV was further detected in several cases of SARS and it was the only virus detected in three deaths. CONCLUSIONS These findings indicate that hMPV is in circulation in southern Brazil and highlight the importance of diagnosing hMPV for influenza-like illness in the population. (AU)

Serosurvey of Avian metapneumovirus, Orithobacterium rhinotracheale, and Chlamydia psittaci and Their Potential Association with Avian Airsacculitis / 生物医学与环境科学（英文）

Seasonal outbreaks of airsacculitis in China's poultry cause great economic losses annually. This study tried to unveil the potential role of Avian metapneumovirus (AMPV), Ornithobacterium rhinotracheale (ORT) and Chlamydia psittaci (CPS) in avian airsacculitis. A serological investigation of 673 breeder chickens and a case-controlled study of 430 birds were undertaken. Results showed that infection with AMPV, ORT, and CPS was highly associated with the disease. The correlation between AMPV and CPS were positively robust in both layers and broilers. Finally, we determined the co-infection with AMPV, ORT, and CPS was prevalent in the sampled poultry farms suffering from respiratory diseases and the outbreak of airsacculitis was closely related to simultaneous exposure to all three agents.

Clinical and laboratory profiles of hospitalized children with acute respiratory virus infection / 소아과

PURPOSE: Despite the availability of molecular methods, identification of the causative virus in children with acute respiratory infections (ARIs) has proven difficult as the same viruses are often detected in asymptomatic children. METHODS: Multiplex reverse transcription polymerase chain reaction assays were performed to detect 15 common respiratory viruses in children under 15 years of age who were hospitalized with ARI between January 2013 and December 2015. Viral epidemiology and clinical profiles of single virus infections were evaluated. RESULTS: Of 3,505 patients, viruses were identified in 2,424 (69.1%), with the assay revealing a single virus in 1,747 cases (49.8%). While major pathogens in single virus-positive cases differed according to age, human rhinovirus (hRV) was common in patients of all ages. Respiratory syncytial virus (RSV), influenza virus (IF), and human metapneumovirus (hMPV) were found to be seasonal pathogens, appearing from fall through winter and spring, whereas hRV and adenovirus (AdV) were detected in every season. Patients with ARIs caused by RSV and hRV were frequently afebrile and more commonly had wheezing compared with patients with other viral ARIs. Neutrophil-dominant inflammation was observed in ARIs caused by IF, AdV, and hRV, whereas lymphocyte-dominant inflammation was observed with RSV A, parainfluenza virus, and hMPV. Monocytosis was common with RSV and AdV, whereas eosinophilia was observed with hRV. CONCLUSION: In combination with viral identification, recognition of virus-specific clinical and laboratory patterns will expand our understanding of the epidemiology of viral ARIs and help us to establish more efficient therapeutic and preventive strategies.

Bronchiolitis severity according to the infected viruses

PURPOSE: The aim of this study was to evaluate the severity of disease in children with acute bronchiolitis according to the type of infected virus. METHODS: From November 2007 to May 2015, 768 patients under 2 years of age who underwent real time-polymerase chain reaction of nasopharyngeal aspirates admitted to the Department of Pediatrics of Dongguk University Ilsan Hospital for acute bronchiolitis were enrolled. Severe bronchiolitis was defined as presence of one or more kinds among tachypnea, chest retraction, needs of O2 inhalation or ventilator care. RESULTS: The severity of bronchiolitis was increased with shorter fever duration (P < 0.001) and previous wheezing episodes (P = 0.005). In the case of single infection, respiratory syncytial virus (RSV) A only increased the severity of acute bronchiolitis (P = 0.012). However, the severity of illness decreased when RSV A coinfected with adenovirus (P = 0.034), human rhinovirus (P = 0.038), or human coronavirus NL63 (P = 0.042). On the other hand, when human rhinovirus was coinfected with enterovirus (P = 0.013) or parainfluenza 3 (P = 0.019), the severity was increased. When human metapneumovirus coinfected with human bocavirus, the severity was increased (P = 0.038). CONCLUSION: Acute bronchiolitis was associated with increased severity only when RSV A infected solely, but several viruses increased or decreased the severity when coinfection occurred. Therefore, it may be helpful in predicting the course of the acute bronchiolitis according to the affected virus.

Distribution and Characterization of Airborne Respiratory Pathogens in Public Facilities

Respiratory infections, which are caused by airborne pathogens, are the most common disease of all ages worldwide. This study was conducted to characterize the airborne respiratory pathogens in the public facilities in Busan, South Korea. A total of 260 public facilities were investigated in 2017, 52 seasonal indoor air from 2 hospitals and 208 indoor air samples from 208 randomly selected daycare centers. Among respiratory pathogen, 8 viral pathogens including human adenovirus (HAdV), human bocavirus (HBoV), human rhinovirus (HRV), human parainfluenza virus (HPIV), human respiratory syncytial virus (HRSV), human metapneumovirus (HMPV), human coronavirus (HCoV) and influenza virus (IFV), and 3 bacterial pathogens including Mycoplasma pneumoniae, Bordetella pertussis, and Chlamydophila pneumoniae, were investigated by multiplex real-time reverse transcription polymerase chain reaction. Pathogens were detected in 9 cases (3.4%). Among 9 positive samples, 6 (2.3%) cases were positive for HBoV and 3 (1.2%) cases were positive for IFV. All the positive cases were detected in daycare centers. Additionally, the concentration of HBoV was determined. In HBoV-positive samples, the cycle threshold (Ct) values of HBoV were 29.73~36.84, which are corresponding to the viral concentration of 4.91 × 10⁰ ~ 9.57 × 10² copies/ml. Serotype distribution of isolated HBoV was analyzed by sequencing of VP1/VP2 gene. All of the HBoV isolates were identified as HBoV type 1 with a high similarity among the isolates (>97%). No bacterial pathogen was identified in indoor air samples. Although virus concentration was not high in public facilities (daycare center), the presence of respiratory viral pathogens has been identified. Effective ventilation and air purification strategies are needed to reduce the indoor concentration of respiratory pathogens. A long-term and ongoing surveillance plan for respiratory pathogen management should be established.

A Retrospective Study Investigating Risks of Acute Respiratory Distress Syndrome and Mortality Following Human Metapneumovirus Infection in Hospitalized Adults / 대한구급학회지

BACKGROUND: Human metapneumovirus (hMPV) is a relatively recently identified respiratory virus that induces respiratory symptoms similar to those of respiratory syncytial virus infection in children. The characteristics of hMPV-infected adults are unclear because few cases have been reported. METHODS: We conducted a retrospective review of hospitalized adult patients with a positive multiplex real-time polymerase chain reaction assay result from 2012 to 2016 at a single tertiary referral hospital in South Korea. We analyzed clinical characteristics of the enrolled patients and divided patients into an acute respiratory distress syndrome (ARDS) group and a non-ARDS group. RESULTS: In total, 110 adults were reviewed in this study. Their mean age was 61.4 years, and the majority (n = 105, 95.5%) had comorbidities or were immunocompromised. Most of the patients had pneumonia on chest X-ray (n = 88, 93.6%), 22 (20.0%) had ARDS, and 12 (10.9%) expired during hospitalization. The mortality rate for patients with ARDS was higher than that of the other patients (36.4% vs. 5.7%, P = 0.001). The risk factor for hMPV-associated ARDS was heart failure (odds ratio, 5.24; P = 0.044) and laboratory values were increased blood urea nitrogen and increased C-reactive protein. The acquisition site of infection was divided into community vs. nosocomial; 43 patients (39.1%) had a nosocomial infection. The risk factors for nosocomial infection were an immunocompromised state, malignancy and immunosuppressive treatment. CONCLUSIONS: These data suggest that hMPV is one of the important respiratory pathogens important respiratory pathogen that causes pneumonia/ARDS in elderly, immunocompromised individuals and that it may be transmitted via the nosocomial route.

Comparison of nasal cytokine profiles of human metapneumovirus and respiratory syncytial virus

BACKGROUND: Human metapneumovirus (hMPV) and respiratory syncytial virus (RSV) share some epidemiological and clinical characteristics; however, few studies have examined the mechanisms by which these viruses induce airway inflammation. OBJECTIVE: This study was undertaken to compare cytokine profiles in hMPV and RSV patients to investigate possible differences in inflammatory pathways. METHODS: Nasopharyngeal aspirate specimens were collected from 1,008 pediatric patients hospitalized for acute lower respiratory tract infection with wheezing and 20 normal healthy controls. Patients were tested for 7 common respiratory viruses then divided into hMPV (n = 35) and RSV groups (n = 67). T helper (Th) 1 (interferon [IFN]-γ), Th2 (interleukin [IL]-4, eotaxin) and Th17 (IL-1β, IL-6) cytokine profiles were analyzed in the 3 groups. RESULTS: IFN-γ and IL-2 levels were significantly increased in the hMPV and RSV groups compared to the control group (p < 0.0001 and p < 0.0001, respectively). IL-4 levels were significantly higher in the RSV group compared to the hMPV and control groups (p = 0.0003 and p < 0.0001, respectively). Eotaxin levels showed a tendency to be higher in the RSV group compared to the hMPV group (p = 0.0580), and significantly higher compared to the control group (p < 0.0001). IL-1β levels were significantly higher in the hMPV compared to the RSV group (p < 0.0001), and IL-6 levels were significantly higher in the hMPV group compared to the control group (p < 0.0001). CONCLUSION: Our results suggest that hMPV and RSV have different inflammatory mechanisms. hMPV induces airway inflammation by the Th17 pathway through release of IL-1β and IL-6, whereas RSV acts through the Th2 pathway.

Study on Causes of Respiratory Disease to the Middle East Respiratory Syndrome-negative Subjects

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe cases of human respiratory disease. The current outbreak of infection with this virus in South Korea, which began on May 20, 2015, has infected 186 patients and caused 36 deaths within 2 months. In this study, to investigate the viral pathogen causing acute respiratory infections, multiplex/RT-PCR was performed on were obtained from nucleic acid of the Middle East Respiratory Syndrome-negative subjects. Viruses and atypical bacteria were detected in 39 of 337 (11.6%). Frequent viruses were human rhinovirus (n=11, 3.3%), human metapneumovirus (n=9, 2.7%), parainfluenza (n=9, 2.7%) and adenovirus (n=4, 1.2%). Mycoplasma pneumonia (M. pneumonia) was detected in 1.8 % (n=6). Out of 9 human metapneumovirus (hMPV) positive samples, 6 samples were successfully sequenced using F gene. And M. pneumoniae was sequencing of a repetitive region of the P1 gene. Phylogenetic analysis revealed that hMPV clustered into A2b lineage (n=4), B2 lineage (n=2) and M. pneumoniae clustered into two genotypes: Type 1 (n=4), Type 2a (n=2).

Study on Causes of Respiratory Disease to the Middle East Respiratory Syndrome-negative Subjects

Middle East respiratory syndrome coronavirus (MERS-CoV) causes severe cases of human respiratory disease. The current outbreak of infection with this virus in South Korea, which began on May 20, 2015, has infected 186 patients and caused 36 deaths within 2 months. In this study, to investigate the viral pathogen causing acute respiratory infections, multiplex/RT-PCR was performed on were obtained from nucleic acid of the Middle East Respiratory Syndrome-negative subjects. Viruses and atypical bacteria were detected in 39 of 337 (11.6%). Frequent viruses were human rhinovirus (n=11, 3.3%), human metapneumovirus (n=9, 2.7%), parainfluenza (n=9, 2.7%) and adenovirus (n=4, 1.2%). Mycoplasma pneumonia (M. pneumonia) was detected in 1.8 % (n=6). Out of 9 human metapneumovirus (hMPV) positive samples, 6 samples were successfully sequenced using F gene. And M. pneumoniae was sequencing of a repetitive region of the P1 gene. Phylogenetic analysis revealed that hMPV clustered into A2b lineage (n=4), B2 lineage (n=2) and M. pneumoniae clustered into two genotypes: Type 1 (n=4), Type 2a (n=2).

A Retrospective Study Investigating Risks of Acute Respiratory Distress Syndrome and Mortality Following Human Metapneumovirus Infection in Hospitalized Adults / 대한중환자의학회지

BACKGROUND: Human metapneumovirus (hMPV) is a relatively recently identified respiratory virus that induces respiratory symptoms similar to those of respiratory syncytial virus infection in children. The characteristics of hMPV-infected adults are unclear because few cases have been reported. METHODS: We conducted a retrospective review of hospitalized adult patients with a positive multiplex real-time polymerase chain reaction assay result from 2012 to 2016 at a single tertiary referral hospital in South Korea. We analyzed clinical characteristics of the enrolled patients and divided patients into an acute respiratory distress syndrome (ARDS) group and a non-ARDS group. RESULTS: In total, 110 adults were reviewed in this study. Their mean age was 61.4 years, and the majority (n = 105, 95.5%) had comorbidities or were immunocompromised. Most of the patients had pneumonia on chest X-ray (n = 88, 93.6%), 22 (20.0%) had ARDS, and 12 (10.9%) expired during hospitalization. The mortality rate for patients with ARDS was higher than that of the other patients (36.4% vs. 5.7%, P = 0.001). The risk factor for hMPV-associated ARDS was heart failure (odds ratio, 5.24; P = 0.044) and laboratory values were increased blood urea nitrogen and increased C-reactive protein. The acquisition site of infection was divided into community vs. nosocomial; 43 patients (39.1%) had a nosocomial infection. The risk factors for nosocomial infection were an immunocompromised state, malignancy and immunosuppressive treatment. CONCLUSIONS: These data suggest that hMPV is one of the important respiratory pathogens important respiratory pathogen that causes pneumonia/ARDS in elderly, immunocompromised individuals and that it may be transmitted via the nosocomial route.

Elucidation of Bacterial Pneumonia-Causing Pathogens in Patients with Respiratory Viral Infection / 결핵및호흡기질환

BACKGROUND: Bacterial pneumonia occurring after respiratory viral infection is common. However, the predominant bacterial species causing pneumonia secondary to respiratory viral infections other than influenza remain unknown. The purpose of this study was to know whether the pathogens causing post-viral bacterial pneumonia vary according to the type of respiratory virus. METHODS: Study subjects were 5,298 patients, who underwent multiplex real-time polymerase chain reaction for simultaneous detection of respiratory viruses, among who visited the emergency department or outpatient clinic with respiratory symptoms at Ulsan University Hospital between April 2013 and March 2016. The patients' medical records were retrospectively reviewed. RESULTS: A total of 251 clinically significant bacteria were identified in 233 patients with post-viral bacterial pneumonia. Mycoplasma pneumoniae was the most frequent bacterium in patients aged <16 years, regardless of the preceding virus type (p=0.630). In patients aged ≥16 years, the isolated bacteria varied according to the preceding virus type. The major results were as follows (p<0.001): pneumonia in patients with influenza virus (type A/B), rhinovirus, and human metapneumovirus infections was caused by similar bacteria, and the findings indicated that Staphylococcus aureus pneumonia was very common in these patients. In contrast, coronavirus, parainfluenza virus, and respiratory syncytial virus infections were associated with pneumonia caused by gram-negative bacteria. CONCLUSION: The pathogens causing post-viral bacterial pneumonia vary according to the type of preceding respiratory virus. This information could help in selecting empirical antibiotics in patients with post-viral pneumonia.

Comparison of Luminex NxTAG Respiratory Pathogen Panel and xTAG Respiratory Viral Panel FAST Version 2 for the Detection of Respiratory Viruses

Owing to advancements in molecular diagnostics, recent years have seen an increasing number of laboratories adopting respiratory viral panels to detect respiratory pathogens. In December 2015, the NxTAG respiratory pathogen panel (NxTAG RPP) was approved by the United States Food and Drug Administration. We compared the clinical performance of this new assay with that of the xTAG respiratory viral panel (xTAG RVP) FAST v2 using 142 clinical samples and 12 external quality assessment samples. Discordant results were resolved by using a laboratory-developed respiratory viral panel. The NxTAG RPP achieved 100% concordant negative results and 86.6% concordant positive results. It detected one coronavirus 229E and eight influenza A/H3N2 viruses that were missed by the xTAG RVP FAST v2. On the other hand, the NxTAG RPP missed one enterovirus/rhinovirus and one metapneumovirus that were detected by FAST v2. Both panels correctly identified all the pathogens in the 12 external quality assessment samples. Overall, the NxTAG RPP demonstrated good diagnostic performance. Of note, it was better able to subtype the influenza A/H3N2 viruses compared with the xTAG RVP FAST v2.

Prevalence of Respiratory Viral Infections in Korean Adult Asthmatics With Acute Exacerbations: Comparison With Those With Stable State

PURPOSE: Viral infections are involved in ~50% of exacerbations among Caucasian adult asthmatics. However, there have been few reports on the causative virus of exacerbations in Korean adult asthmatics. Thus, we compared frequencies and types of viruses between lower respiratory tract illnesses (LRTIs) with exacerbations (exacerbated LRTIs) and those without exacerbations (stable LRTIs) to evaluate contribution of respiratory viruses to exacerbations. METHODS: Viral RNA was extracted from sputum using the Viral Gene-spin™ Kit. Reverse transcription-polymerase chain reaction (RT-PCR) was performed to detect adenovirus (ADV), metapneumovirus (MPV), parainfluenza virus (PIV) 1/2/3, influenza virus (IFV) A, IFV B, respiratory syncytial virus (RSV) A/B, and rhinovirus (RV) A. RESULTS: Among the 259 patients, 210 underwent a single sputum examination, and the remaining 49 underwent 2 to 4 sputum examinations. Virus was detected in 68 of the 259 exacerbated episodes and in 11 of the 64 stable episodes. Among the exacerbated episodes, RV was the most frequently detected virus, followed by influenza A, parainfluenza, RSV A/B, and ADV. Among the 11 stable episodes, RV was most frequently detected. Detection rates of these viruses did not differ between the 2 groups (P>0.05). Thirty-five patients underwent the virus examination at 2 episodes of exacerbation, while 14 patients underwent at each time of exacerbated and stable episodes. Virus detection rate at the second examination was significantly higher in cases with 2 exacerbation episodes than in those with initial exacerbation and sequential stable episodes (P=0.003). A seasonal pattern was noted in the detection rates of RV (September to December), IFV (January to April), PIV (May to September), and RSV A/B (September to April). CONCLUSIONS: Respiratory viruses were identified in approximately 20% of LRTI irrespective of the presence of asthma exacerbation. RV and IFV A/B were most frequently detected. A group of patients experienced frequent viral infections followed by asthma exacerbations.