Severe necrotizing tracheobronchitis caused by influenza B and methicillin-resistant Staphylococcus aureus co-infection in an immunocompetent patient.

PURPOSE AND METHOD: Necrotizing tracheobronchitis is a rare clinical entity presented as a necrotic inflammation involving the mainstem trachea and distal bronchi. We reported a case of severe necrotizing tracheobronchitis caused by influenza B and methicillin-resistant Staphylococcus aureus (MRSA) co-infection in an immunocompetent patient. CASE PRESENTATION: We described a 36-year-old man with initial symptoms of cough, rigors, muscle soreness and fever. His status rapidly deteriorated two days later and he was intubated. Bronchoscopy demonstrated severe necrotizing tracheobronchitis, and CT imaging demonstrated multiple patchy and cavitation formation in both lungs. Next-generation sequencing (NGS) and bronchoalveolar lavage fluid (BALF) culture supported the co-infection of influenza B and MRSA. We also found T lymphocyte and NK lymphocyte functions were extremely suppressed during illness exacerbation. The patient was treated with antivirals and antibiotics including vancomycin. Subsequent bronchoscopy and CT scans revealed significant improvement of the airway and pulmonary lesions, and the lymphocyte functions were restored. Finally, this patient was discharged successfully. CONCLUSION: Necrotizing tracheobronchitis should be suspected in patients with rapid deterioration after influenza B infection. The timely diagnosis of co-infection and accurate antibiotics are important to effective treatment.

miR-122 promotes virus-induced lung disease by targeting SOCS1.

Virus-induced respiratory tract infections are a major health burden in childhood, and available treatments are supportive rather than disease modifying. Rhinoviruses (RVs), the cause of approximately 80% of common colds, are detected in nearly half of all infants with bronchiolitis and the majority of children with an asthma exacerbation. Bronchiolitis in early life is a strong risk factor for the development of asthma. Here, we found that RV infection induced the expression of miRNA 122 (miR-122) in mouse lungs and in human airway epithelial cells. In vivo inhibition specifically in the lung reduced neutrophilic inflammation and CXCL2 expression, boosted innate IFN responses, and ameliorated airway hyperreactivity in the absence and in the presence of allergic lung inflammation. Inhibition of miR-122 in the lung increased the levels of suppressor of cytokine signaling 1 (SOCS1), which is an in vitro-validated target of miR-122. Importantly, gene silencing of SOCS1 in vivo completely reversed the protective effects of miR-122 inhibition on RV-induced lung disease. Higher miR-122 expression in nasopharyngeal aspirates was associated with a longer time on oxygen therapy and a higher rate of treatment failure in 87 infants hospitalized with moderately severe bronchiolitis. These results suggest that miR-122 promotes RV-induced lung disease via suppression of its target SOCS1 in vivo. Higher miR-122 expression was associated with worse clinical outcomes, highlighting the potential use of anti-miR-122 oligonucleotides, successfully trialed for treatment of hepatitis C, as potential therapeutics for RV-induced bronchiolitis and asthma exacerbations.

Plastic bronchitis due to adenoviral infection: a case report.

BACKGROUND: Plastic bronchitis (PB) frequently occurs as a serious postoperative complication of the Fontan procedure. The definitive causes of PB are unknown. CASE PRESENTATION: Herein, we report a pediatric case of PB secondary to adenoviral infection. A 4-year-old girl was admitted to the general pediatric ward for cough since 2 weeks and fever since 11 days. Consolidated lesions were noted in the right upper and both lower lung lobes. Extracorporeal membrane oxygenation was performed because the patient's respiratory failure remained unalleviated despite the use of a ventilator. Bronchial dendritic casts were extracted using flexible bronchoscopy, and the patient's breathing improved. Pathological examination of the dendritic cast confirmed the diagnosis of type I PB. The exfoliated cells of sputum and cells from bronchoalveolar lavage fluid were positive for adenoviral antigen. Human adenovirus 7 was detected by next-generation sequencing of the bronchoalveolar lavage fluid. The patient recovered and was discharged 39 days after admission without recurrence of cough or wheezing. CONCLUSIONS: PB due to human adenovirus 7 infection should be considered in children with persistent respiratory failure. Flexible bronchoscopy should be performed early to confirm diagnosis and to remove any airway obstruction.

The Infectious Bronchitis Coronavirus Envelope Protein Alters Golgi pH To Protect the Spike Protein and Promote the Release of Infectious Virus.

Coronaviruses (CoVs) assemble by budding into the lumen of the early Golgi complex prior to exocytosis. The small CoV envelope (E) protein plays roles in assembly, virion release, and pathogenesis. CoV E has a single hydrophobic domain (HD), is targeted to Golgi membranes, and has cation channel activity in vitro The E protein from avian infectious bronchitis virus (IBV) has dramatic effects on the secretory system, which require residues in the HD. Mutation of the HD of IBV E in a recombinant virus background results in impaired growth kinetics, impaired release of infectious virions, accumulation of IBV spike (S) protein on the plasma membrane compared to wild-type (WT) IBV-infected cells, and aberrant cleavage of IBV S on virions. We previously reported the formation of two distinct oligomeric pools of IBV E in transfected and infected cells. Disruption of the secretory pathway by IBV E correlates with a form that is likely monomeric, suggesting that the effects on the secretory pathway are independent of E ion channel activity. Here, we present evidence suggesting that the monomeric form of IBV E correlates with an increased Golgi luminal pH. Infection with IBV or expression of IBV E induces neutralization of Golgi pH, promoting a model in which IBV E alters the secretory pathway through interaction with host cell factors, protecting IBV S from premature cleavage and leading to the efficient release of infectious virus from the cells. This is the first demonstration of a coronavirus-induced alteration in the microenvironment of the secretory pathway.IMPORTANCE Coronaviruses are important human pathogens with significant zoonotic potential. Progress has been made toward identifying potential vaccine candidates for highly pathogenic human CoVs, including the use of attenuated viruses that lack the CoV E protein or express E mutants. However, no approved vaccines or antiviral therapeutics exist. Understanding the role of the CoV E protein in virus assembly and release is thus an important prerequisite for potential vaccines as well as in identifying novel antiviral therapeutics.

Fatal, Fulminant Herpetic Tracheobronchitis following Cardiac Surgery.

Nosocomial infection is a feared complication after any surgical procedure. Respiratory tract microbial colonization and development of ventilator-associated tracheobronchitis and/or pneumonia are unfortunate sequelae in mechanically ventilated patients, commonly caused by bacteria; viral etiology is seldom anticipated. We present a fatal case of fulminant herpetic tracheobronchitis in a 33-month-old patient following cardiac surgery. We intend to highlight the fact that herpetic viral etiology should be considered in post-operative respiratory infections.

Human T-Lymphotropic Virus type 1c subtype proviral loads, chronic lung disease and survival in a prospective cohort of Indigenous Australians.

BACKGROUND: The Human T-Lymphotropic Virus type 1c subtype (HTLV-1c) is highly endemic to central Australia where the most frequent complication of HTLV-1 infection in Indigenous Australians is bronchiectasis. We carried out a prospective study to quantify the prognosis of HTLV-1c infection and chronic lung disease and the risk of death according to the HTLV-1c proviral load (pVL). METHODOLOGY/PRINCIPAL FINDINGS: 840 Indigenous adults (discharge diagnosis of bronchiectasis, 154) were recruited to a hospital-based prospective cohort. Baseline HTLV-1c pVL were determined and the results of chest computed tomography and clinical details reviewed. The odds of an association between HTLV-1 infection and bronchiectasis or bronchitis/bronchiolitis were calculated, and the impact of HTLV-1c pVL on the risk of death was measured. Radiologically defined bronchiectasis and bronchitis/bronchiolitis were significantly more common among HTLV-1-infected subjects (adjusted odds ratio = 2.9; 95% CI, 2.0, 4.3). Median HTLV-1c pVL for subjects with airways inflammation was 16-fold higher than that of asymptomatic subjects. There were 151 deaths during 2,140 person-years of follow-up (maximum follow-up 8.13 years). Mortality rates were higher among subjects with HTLV-1c pVL ≥1000 copies per 105 peripheral blood leukocytes (log-rank χ2 (2df) = 6.63, p = 0.036) compared to those with lower HTLV-1c pVL or uninfected subjects. Excess mortality was largely due to bronchiectasis-related deaths (adjusted HR 4.31; 95% CI, 1.78, 10.42 versus uninfected). CONCLUSION/SIGNIFICANCE: Higher HTLV-1c pVL was strongly associated with radiologically defined airways inflammation and with death due to complications of bronchiectasis. An increased risk of death due to an HTLV-1 associated inflammatory disease has not been demonstrated previously. Our findings indicate that mortality associated with HTLV-1c infection may be higher than has been previously appreciated. Further prospective studies are needed to determine whether these results can be generalized to other HTLV-1 endemic areas.

Up-regulation of serum periostin and squamous cell carcinoma antigen levels in infants with acute bronchitis due to respiratory syncytial virus.

BACKGROUND: Periostin and squamous cell carcinoma antigen (SCCA) are involved in the pathogenesis of asthma. Acute bronchitis due to respiratory syncytial virus (RSV) infection during infancy exhibits an asthma-like pathogenesis, suggesting that it may be associated with the subsequent development of asthma. However, the mechanism by which RSV infection leads to development of asthma has not yet been fully elucidated. METHODS: Infants younger than 36 months were enrolled and classified into three groups. Group I included patients hospitalized with RSV-induced bronchitis. These patients were further stratified into two sub-groups according to whether the criteria for the modified Asthma Predictive Index (mAPI) had been met: Group I consisted of mAPI (+) and mAPI (-) patients; Group II included patients with food allergy as a positive control group; and Group III included children with no allergy as a negative control group. Serum periostin and SCCA levels were measured in the groups. This study was registered as a clinical trial (UMIN000012339). RESULTS: We enrolled 14 subjects in Group I mAPI (+), 22 in Group I mAPI (-), 18 in Group II, and 18 in Group III. In Group I, the serum periostin and SCCA levels were significantly higher during the acute phase compared with the recovery phase. However, no significant differences were found between Group I mAPI (+) and mAPI (-). CONCLUSIONS: The serum periostin and SCCA levels increased during acute RSV bronchitis. Both periostin and SCCA may play a role in the pathogenesis of acute bronchitis due to RSV.

Genetic diversity of human metapneumovirus in hospitalized children with acute respiratory infections in Croatia.

Human metapneumovirus (HMPV) is recognized as a global and frequent cause of acute respiratory tract infections among people of all ages. The objectives of this study were molecular epidemiology and evolutionary analysis of HMPV strains which produced moderate and severe acute respiratory tract infections in children in Croatia during four consecutive seasons (2011-2014). A total of 117 HMPV-positive samples collected from hospitalized pediatric patients presenting with acute respiratory tract infections and tested by direct immunofluorescence assay were first analyzed by amplifying a part of the F gene. Sixteen samples were further analyzed based on complete F, G, and SH gene sequences. HMPV genome was identified in 92 of 117 samples (78%) and the circulation of multiple lineages of HMPV was confirmed. In 2011, 2012, and 2014, subgroups A2 and B2 co-circulated, while B1 gained prevalence in 2013 and 2014. The study established the presence of a novel subcluster A2c in Croatia. This subcluster has only recently been detected in East and Southeast Asia. This study provides new insights into epidemiology and genetic diversity of HMPV in this part of Europe.

Molecular characterization of quail bronchitis virus isolated from bobwhite quail in Minnesota.

From 2008 to 2012, 4 separate cases of quail bronchitis virus infection were seen in bobwhite quail (Colinus virginianus) raised in Minnesota. The quail chicks ranged in age from 5 d to 8 wk and suffered from respiratory distress and elevated mortality. On necropsy, gross lesions consisted of mucus in trachea, congested lungs, caseous air sacculitis, accumulation of chalky white urates on internal organs, necrotic foci in liver, and enlarged spleen. Histologic examination revealed fibrinoheterophilic rhinitis, heterophilic bronchitis, heterophilic tracheitis, and interstitial pneumonia in addition to deciliation, desquamation, and necrosis of bronchial respiratory epithelium. Karyomegaly with basophilic intranuclear inclusions was also seen in affected epithelium. Severe epicarditis, pericarditis, myocarditis, multifocal necrotizing hepatitis, and splenitis were additional pathological findings. Quail bronchitis virus (QBV) was isolated from all four samples when inoculated in specific-pathogen-free (SPF) embryonated chicken eggs. The virus was confirmed by electron microscopy and polymerase chain reaction using fowl adenovirus (FAdV) hexon gene-specific primers. Nucleotide sequences of the four isolates showed 99.0% identity with CELO strain of fowl adenovirus A. Nine nucleotide substitutions were observed; 3 of these were nonsynonymous (A281G, C314T and G565C), leading to changes in deduced amino acid sequences (S94G, T105M and A189P, respectively). Based on partial sequence of the hexon gene, QBV isolates of this study clustered closely with fowl adenovirus A and were different from FAdV groups B through E and from adenoviruses of goose, duck, turkey, and pigeon. Further studies are indicated to determine the impact of nonsynonymous substitutions on host specific pathogenicity of these viruses.

Molecular evolution of the hypervariable region of the attachment glycoprotein gene in human respiratory syncytial virus subgroup B genotypes BA9 and BA10.

We studied the molecular evolution of the C-terminal 3rd hypervariable region in the attachment glycoprotein gene of human respiratory syncytial virus subgroup B (HRSV-B) genotypes BA9 and BA10. We performed time-scaled phylogenetic analyses using Bayesian Markov chain Monte Carlo methods. We also performed a genetic distance analysis (p-distance analysis), positive and negative selection analyses, and a Bayesian skyline plot (BSP) analysis. We found that genotype BA9 diverged from the common ancestor of genotypes BA7, BA8, and BA10, while genotype BA10 diverged from the ancestor of genotypes BA7 and BA8. Strains of both genotypes were distributed worldwide. BA9 and BA10 diverged between 1999 and 2001. Both BA9 and BA10 evolved rapidly (about 4.8×10(-3)substitutions/site/year) and formed three distinct lineages in a 10-year period. BA10 strains belonging to lineage 3 had large genetic distances (p-distance>0.07). Thus, it may be possible to classify these strains as a new genotype, BA11. No positive selection site was detected in either genotype. Phylodynamic analyses showed that the effective population size of BA10 decreased gradually since 2010 and BA9 slightly decreased since 2009. The results suggested that the recently prevalent HRSV-B genotypes BA9 and BA10 evolved uniquely, leading to epidemics of HRSV-B worldwide over a 15-year period.

Molecular Epidemiology and Phylogenetic Analysis of Human Adenovirus Caused an Outbreak in Taiwan during 2011.

An outbreak of adenovirus has been surveyed in Taiwan in 2011. To better understand the evolution and epidemiology of adenovirus in Taiwan, full-length sequence of hexon and fiber coapsid protein was analyzed using series of phylogenetic and dynamic evolution tools. Six different serotypes were identified in this outbreak and the species B was predominant (HAdV-3, 71.50%; HAdV-7, 15.46%). The most frequent diagnosis was acute tonsillitis (54.59%) and bronchitis (47.83%). Phylogenetic analysis revealed that hexon protein gene sequences were highly conserved for HAdV-3 and HAdV-7 circulation in Taiwan. However, comparison of restriction fragment length polymorphism (RFLP) analysis and phylogenetic trees of fiber gene in HAdV-7 clearly indicated that the predominant genotype in Taiwan has shifted from 7b to 7d. Several positive selection sites were observed in hexon protein. The estimated nucleotide substitution rates of hexon protein of HAdV-3 and HAdV-7 were 0.234×10-3 substitutions/site/year (95% HPD: 0.387~0.095×10-3) and 1.107×10-3 (95% HPD: 0. 541~1.604) respectively; those of the fiber protein of HAdV-3 and HAdV-7 were 1.085×10-3 (95% HPD: 1.767~0.486) and 0.132×10-3 (95% HPD: 0.283~0.014) respectively. Phylodynamic analysis by Bayesian skyline plot (BSP) suggested that using individual gene to evaluate the effective population size might possibly cause miscalculation. In summary, the virus evolution is ongoing, and continuous surveillance of this virus evolution will contribute to the control of the epidemic.

Plastic bronchitis associated with influenza virus infection in children: a report on 14 cases.

BACKGROUND: Plastic bronchitis (PB) is a rare disease characterized by formation of bronchial casts. It is usually associated with congenital heart disease, sickle cell disease, lymphoma, and lung diseases such as asthma and pneumonia. OBJECTIVES: To report 14 cases of PB with influenza A or influenza B infection. METHODS: We analyzed the clinical manifestations, bronchoscopic and histologic findings, clinical courses, and outcomes. RESULTS: These cases indicate that PB is a life-threatening complication of severe influenza. Plastic bronchitis should be considered in the diagnosis of children with acute respiratory distress such as lung atelectasis accompanied by influenza. CONCLUSIONS: Diagnosis should be made by bronchial endoscopy and histopathology, and bronchial casts removed as early as possible.

[Analysis on diagnosis and treatment of 15 cases with severe influenza A].

OBJECTIVE: To analyze the diagnosis and treatment characteristics of patients with severe Influenza A. METHOD: A retrospective investigation on the clinical manifestation, chest radiography, electronic fiber bronchoscopy and the histology of the cast, rescue course and outcome was conducted in 15 children with severe influenza A during January to May of 2013. RESULT: Eleven cases were male, the range of age was 2 to 6 years; 5 cases were female, the range of age was 1 month to 6 years, accouting for 4.2% of hospitalized children with influenza. Three patients had an underlying chronic disease, two had nephrotic syndrome, and one had congenital heart disease. All the 15 cases were diagnosed as severe influenza A virus infection complicated with pneumonia and respiratory failure, of whom 10 cases were infected with H1N1 virus , the other 5 cases could not be identified as H1N1 virus by using H1N1 kit, but none of the 15 cases were infected with H7N9 virus. Of 15 cases, 8 had atelectasis, 4 had pneumothorax, 3 had pneumomediastinum, 4 had pleural effusion, 1 had pneumorrhagia; 12 patients required mechanical ventilation. 1 only required noninvasive mask CPAP, 2 did not require assisted ventilation, they were just given mask oxygen. Seven cases' sputum culture showed combined infection with bacteria and fungi, sputum smear examination detected: G(+) cocci in 2 cases, and G(-) bacilli in the other 2. By using electronic fiber bronchoscopy, bronchial cast was detected in 5 patiens. Histological examination of the bronchial cast revealed a fibrinous exudation containing large quantity of eosinophils, neutrophils in 1 patients, fibrinous exudation and necrotic material containing large quantity of neutrophils in 4 patients. After the bronchial casts were removed, 4 patients were improved greatly. All patients were treated with postural drainage of left and right side position, massage of electric oscillation, strengthening the sputum suction aiming to improve pulmonary ventilation function. Three patients died: 1 case was compliicated with nephrotic syndrome, another case had congenital heart disease, and 1 case hads pneumorrhagia, renal failure and multiple organ dysfunction syndrome (MODS). CONCLUSION: The mortality of severe Influenza A is higher if it is complicated with underlying chronic diseases. In children undergoing rapid and progressive respiratory distress with lung atelectasis, consolidation or emphysema on chest X-ray, plastic bronchitis should be considered. Electronic fiber bronchoscopy should be performed early Lung physicotherapeutics still are important assistant measures for improving the pulmonary ventilation function.

Simultaneous atelectasis in human bocavirus infected monozygotic twins: was it plastic bronchitis?

BACKGROUND: Plastic bronchitis is an extremely rare disease characterized by the formation of tracheobronchial airway casts, which are composed of a fibrinous exudate with rubber-like consistency and cause respiratory distress as a result of severe airflow obstruction. Bronchial casts may be associated with congenital and acquired cardiopathies, bronchopulmonary diseases leading to mucus hypersecretion, and pulmonary lymphatic abnormalities. In recent years, however, there is growing evidence that plastic bronchitis can also be triggered by common respiratory tract infections and thereby cause atelectasis even in otherwise healthy children. CASE PRESENTATION: We report on 22-month-old monozygotic twins presenting with atelectasis triggered by a simple respiratory tract infection. The clinical, laboratory, and radiographic findings given, bronchial cast formation was suspected in both infants but could only be confirmed after bronchoscopy in the first case. Real-time polymerase chain reaction of the removed cast as well as nasal lavage fluid of both infants demonstrated strong positivity for human bocavirus. CONCLUSION: Our case report is the first to describe two simultaneously affected monozygotic twins and substantiates the hypothesis of a contributing genetic factor in the pathophysiology of this disease. In this second report related to human bocavirus, we show additional evidence that this condition can be triggered by a simple respiratory tract infection in previously healthy infants.

Clinical characteristics of adenovirus associated lower respiratory tract infection in children.

BACKGROUND: Acute lower respiratory tract infection (ALRI) due to adenovirus infection is a low frequency event but often causes severe outcome. This study was undertaken to uncover the clinical and epidemiological features of adenovirus infection in children. METHODS: Hospitalized children with ALRI were analyzed through continuous monitoring from 2006 to 2012. Nasopharyngeal aspirates were examined by direct immunofluorescence to detect respiratory agents including respiratory syncytial virus, adenovirus, influenza virus types A/B, parainfluenza virus types 1/2/3. Chlamydia pneumonia, Mycoplasma pneumonia and Chlamydia trachomatis were determined by real-time PCR. A retrospective analysis was made of 479 patients with positive infection of adenovirus. RESULTS: The positive detection rate of adenovirus was 0.63% in patients with ALRI. The incidence rate of adenovirus-associated acute lower respiratory tract infection peaked at the second six months of life. The morbidity was much higher in winter, spring and summer than in autumn. Patients with pneumonia accounted for 73.90% of the patients. More than one-third of the patients developed severe pneumonia, whereas no death was found. Features of severe adenovirus-associated lower respiratory tract infection included persistent high fever with serious infective symptoms, and hepatic dysfunction was one of the most common complications. Mixed infection of atypical pathogens was common (18.58%) in this study. CONCLUSIONS: Adenovirus is a critical pathogen that can cause severe respiratory infections even in immunocompetent children. Coinfection of adenovirus with atypical pathogens is common. Antibiotic treatment with azithromycin or erythromycin is necessary in patients with mixed infection of atypical pathogens.

Influenza and respiratory syncytial virus are the major respiratory viruses detected from prospective testing of pediatric and adult coronial autopsies.

BACKGROUND: To ascertain the full mortality of influenza and other respiratory viruses, the testing of community autopsy specimens is essential. METHODS: Respiratory virus PCR and culture were performed on 2418 fresh unfrozen respiratory samples collected from 1611 coronial cases where the death was either unknown or infection was suspected, from July 2007 to June 2011, to detect the common respiratory viruses in children and adults, using standardized microbiological testing. RESULTS: The respiratory virus positive rate was 8·3% (134 cases) with a peak of 28% (42 of 151 cases) in children under 10 years of age. Influenza virus was the commonest respiratory virus (50 cases, 3%), followed by respiratory syncytial virus (RSV) (30 cases, 2%). All tested respiratory viruses were found in children, most commonly adenovirus, enterovirus and RSV, and influenza A and RSV predominated in those over 60 years, but coinfection was uncommon. Almost all influenza cases occurred when influenza was widely circulating in the community but few were diagnosed pre-mortem. Influenza and RSV detection was associated with bronchitis or bronchiolitis in 7 (9%) of the 80 cases and caused pneumonia in 14 (0·8%) deaths overall. CONCLUSIONS: Our prospective review of respiratory viruses using standardized testing found a single lower respiratory tract autopsy specimen for respiratory virus PCR would detect most community infections at the time of death.

Identification of a novel cetacean polyomavirus from a common dolphin (Delphinus delphis) with Tracheobronchitis.

A female short-beaked common dolphin calf was found stranded in San Diego, California in October 2010, presenting with multifocal ulcerative lesions in the trachea and bronchi. Viral particles suggestive of polyomavirus were detected by EM, and subsequently confirmed by PCR and sequencing. Full genome sequencing (Ion Torrent) revealed a circular dsDNA genome of 5,159 bp that was shown to form a distinct lineage within the genus Polyomavirus based on phylogenetic analysis of the early and late transcriptomes. Viral infection and distribution in laryngeal mucosa was characterised using in-situ hybridisation, and apoptosis observed in the virus-infected region. These results demonstrate that polyomaviruses can be associated with respiratory disease in cetaceans, and expand our knowledge of their diversity and clinical significance in marine mammals.

[Investigation of adenoviruses in children with lower respiratory tract infections]. / Alt solunum yolu enfeksiyonu olan çocuklarda adenoviruslarin arastirilmasi

Adenoviruses which are one of the causative agents of acute respiratory tract infections at all age groups worldwide, can lead to epidemic, endemic or sporadic infections year-round. Adenovirus infections in lower respiratory tract can be presented as bronchitis, bronchiolitis and pneumonia. The aim of this study was to investigate the presence of adenoviruses as the etiologic agent of lower respiratory tract infections (LRTIs) in children by cell culture, polymerase chain reaction (PCR) and direct fluorescence antibody (DFA) test. The results of the laboratory tests were evaluated in the light of patients' clinical findings. The study consisted of 206 patients aged between 0-5 years old and who were admitted to the hospital with the complaints of LRTI between January 2011 and April 2012. The clinical, radiological and laboratory findings of the patients were recorded. Nasopharyngeal specimens were taken with flocked swab from all patients and adenoviruses were investigated by shell-vial cell culture, real-time PCR and DFA test, simultaneously. Of all the samples 89.3% were taken in January, February and March and 38% of the patients have one or more chronic underlying diseases as chromosomal abnormalities, congenital heart disease, heart failure, asthma, cystic fibrosis, leukemia, kidney failure and prematurity. Adenovirus was detected in 12 (5.8%) of the samples by PCR, seven (3.4%) of the samples by cell culture method. While seven samples were found positive with both PCR and cell culture, 194 samples yielded negative results in both tests. Five samples, which were found positive by PCR, were not grown in cell culture method. Twelve of the 153 samples examined with DFA test, could not be evaluated due to insufficient amount of cells, however 2.8% (4/141) of the samples were found positive for adenovirus antigens by DFA method. Those samples were also positive ones in the other two methods. Compared with cell culture, the sensitivity, specificity, positive and negative predictive values of PCR were 100%, 97.5%, 58.3% and 100%, respectively; those values were 57%,100%,100% and 97.7%, respectively for DFA testing. Compared to PCR the sensitivity of cell culture is very low (16.6%) after three days of incubation, however, it increased to 58.3% after five days' of incubation. There was no significant relationship between adenovirus positivity and the presence of chronic diseases, the radiological findings and the laboratory findings. Of all adenovirus positive samples 83.3% were obtained in January, February and March. Our data indicated that the etiological agent was adenovirus in approximately 6% of children with LRTI. The most important step for the isolation of adenovirus from respiratory tract, is high quality and sufficient amounts of sample. The flexible flocked swabs made it easy to take nasopharyngeal swab from children. Although cell culture is still the gold standard for the diagnosis of adenovirus infections, PCR which is a fast method with high sensitivity and specificity can also be used. However, specific care should be taken during the DNA extraction stage, since the amount of the nucleic acid in the sample is critical for the best results. Even though the low sensitivity of DFA restricts its use in routine diagnosis of adenovirus infections, it should always be kept in mind that the quality of the clinical samples is most reliably evaluated by this method.

[Clinical analysis of 8 children with plastic bronchitis associated with influenza A virus (H1N1) infection].

OBJECTIVE: To analyze the clinical characteristics of plastic bronchitis associated with 2009 influenza A virus (H1N1) infection. METHOD: A retrospective investigation of the clinical manifestation, bronchoscopy, and the histology of the cast, clinical course and outcome of 8 children with plastic bronchitis associated with influenza A virus (H1N1) infection during winter of 2009 and 2010 was performed. RESULT: All 8 cases were boys, the range of age was 3 to 6 years. Five cases occurred in 2009 winter, accounting for 3.3% (5/150) of hospitalized children with influenza A (H1N1) infection; 3 cases occurred in 2010 winter, accounting for 15.8% (3/19) of hospitalized children with influenza A (H1N1) infection. Two patients had an underlying chronic disease, 1 had asthma, and the other had allergic rhinitis and atopic dermatitis. All the 8 cases had fever, cough and sputum; 2 had wheezing; 5 had respiratory distress. All 8 cases were diagnosed as influenza A virus (H1N1) infection complicated with pneumonia, of whom 5 patients had atelectasis, 2 had pneumothorax, 1 had pneumomediastinum, 1 had parapneumonic effusion, 2 patients were suspected of foreign body aspiration. Seven cases were admitted to an ICU, 5 patients developed respiratory failure, and 3 patients required mechanical ventilation. Flexible bronchoscopy and bronchial lavage was performed in all cases and showed bronchial cast. Histological examination of the bronchial cast revealed a fibrinous material containing large quantity of eosinophils, neutrophils, and lymphocytes in 7 patients, fibrinous material and necrotic material without inflammatory cells in 1 patient. After the bronchial cast was removed, all patients were improved greatly, no patients died. CONCLUSION: Plastic bronchitis is a life-threatening complication associated with 2009 influenza A (H1N1) virus infection in children. In children with rapid and progressive respiratory distress with lung atelectasis or consolidation on chest radiograph, plastic bronchitis should be considered. Bronchoscopic extraction of casts should be carried out early.