A rare pathogen causing pulmonary infection and liver dysfunction in a 46-day-old infant: Rhizobium radiobacter.

Rhizobium radiobacter is an aerobic, motile, oxidase-positive, non-spore-forming Gram-negative tumorigenic plant pathogen which rarely infects humans. A 46-day-old girl was admitted to hospital with a 10-day history of fever and cough. She had pneumonia and liver dysfunction owing to infection by R. radiobacter. After 3 days of treatment with ceftriaxone, (compound glycyrrhizin and ambroxol), her body temperature returned to normal and the pneumonia improved, but liver enzyme levels continued to rise. After treatment with meropenem (glycyrrhizin and reduced glutathione), her condition stabilised and she recovered with no liver damage, and was discharged after 15 days. R. radiobacter has low virulence and antibiotics are highly sensitive, but, rarely, severe organ dysfunction can occur and result in multi-system damage in vulnerable children.

Plastic bronchitis associated with influenza A virus in children with asthma.

Plastic bronchitis (PB) is a rare and potentially fatal disease characterized by acute progressive dyspnea caused by bronchial casts in the bronchial tree. We analyzed two children with asthma and PB who presented with high fever, cough and dyspnea. Both cases showed acute onset and rapid disease progression. Laboratory examination revealed that both children were infected with influenza A virus. Emergency fiberoptic bronchoscopy was performed within 20 hours of admission. Immediately after removing the bronchial casts, their dyspnea symptoms improved significantly, and they recovered after comprehensive treatment with antiviral drugs, antibiotics and glucocorticoids. When children with asthma have acute progressive and difficult-to-relieve dyspnea after infection with influenza A virus, clinicians should be aware of the possibility of PB and perform bronchoscopy as soon as possible to facilitate early diagnosis and treatment and improve patient prognosis.

The effect of recombinant human interferon α1b treatment of infants hospitalized with lower respiratory tract infection on subsequent wheezing

Abstract Objective: To investigate the impact of recombinant human interferon α1b (rhIFNα1b) treatment in infants hospitalized with lower respiratory tract infections on subsequent wheezing. Methods: The clinical data of infants (n = 540) with viral pneumonia, wheezy bronchitis, or bronchiolitis hospitalized in 19 Chinese hospitals from June 2009 to June 2015 were retrospectively analyzed. The parameters relevant to wheezing episodes within the last year were collected by telephone and questionnaires. The rhIFNα1b treatment group (n = 253) and control group (n = 287) were compared in terms of wheezing episodes within the last year. Moreover, the wheezing group (95 cases) and non-wheezing group (445 cases) were compared. Results: Out of 540 cases, 95 (17.6%) experienced wheezing episodes, 13.8% (35/253) cases treated with rhIFNα1b, and 20.9% (60/287) cases without rhIFNα1b experienced wheezing episodes within the last year. The rhIFNα1b treatment significantly improved wheezing episodes within the last year, compared with the control peers (p = 0.031). Single-factor regression showed statistically significant differences between the wheezing and non-wheezing groups in terms of age, rhIFNα1b use, childhood and family history of allergy, housing situation, and feeding history (p < 0.05). Binary logistic regression showed a childhood history of allergy (OR = 2.14, p = 0.004), no rhIFNα1b use (OR = 1.70, p = 0.028), and living in a crowded house (OR = 1.92, p = 0.012) might be risk factors of subsequent wheezing. Accordingly, breastfeeding (OR = 0.44, p = 0.008) and hospitalization age of 1-year-old (OR = 0.58, p = 0.024) were protective factors. Conclusions: Early use of rhIFNα1b in infants hospitalized with lower respiratory tract infections and breastfeeding could prevent subsequent wheezing. Living in a crowded house could promote subsequent wheezing.

Molecular Characteristics of Human Adenovirus Type 3 Circulating in Parts of China During 2014-2018.

Human adenoviruses (HAdVs) are important pathogens causing respiratory infections; 3.5-11% of childhood community-acquired pneumonia is associated with HAdV infection. Human adenovirus type 3 (HAdV-3), leading to severe morbidity and mortality, is one of the most prevalent genotype among adenoviruses responsible for acute respiratory infections (ARIs) in children in China. To identify the genetic variation of HAdV-3 in children with ARIs in China, a molecular epidemiological study was conducted. A total of 54 HAdV-3 isolated strains were obtained from children with ARIs in Beijing, Wenzhou, Shanghai, Shijiazhuang, Hangzhou, Guangzhou, and Changchun from 2014 to 2018. Thirty-two strains of which were selected for whole-genome sequencing, while the hexon, penton base, and fiber genes were sequenced for remaining strains. Bioinformatics analysis was performed on the obtained sequences. The phylogenetic analyses based on whole-genome sequences, major capsid protein genes (hexon, penton base, and fiber), and early genes (E1, E2, E3, and E4) showed that the HAdV-3 strains obtained in this study always clustered together with the reference strains from Chinese mainland, while the HAdV-3 prototype strain formed a cluster independently. Compared with the prototype strain, all strains possessed nine amino acid (AA) substitutions at neutralization antigenic epitopes of hexon. The homology models of the hexon protein of the HAdV-3 prototype and strain BJ20160214 showed that there was no evident structural change at the AA mutation sites. Two AA substitutions were found at the Arg-Gly-Asp (RGD) loop and hypervariable region 1 (HVR1) region of the penton base. A distinct AA insertion (20P) in the highly conserved PPPSY motif of the penton base that had never been reported before was observed. Recombination analysis indicated that partial regions of protein IIIa precursor, penton base, and protein VII precursor genes among all HAdV-3 strains in this study were from HAdV-7. This study showed that the genomes of the HAdV-3 strains in China were highly homologous. Some AA mutations were found at antigenic sites; however, the significance needs further study. Our data demonstrated the molecular characteristics of HAdV-3 circulating in China and was highly beneficial for further epidemiological exploration and the development of vaccines and drugs against HAdV-3.

Genetic Analysis of Human Adenovirus Type 7 Strains Circulating in Different Parts of China.

To investigate the molecular epidemiology and genetic variation of human adenovirus type 7 (HAdV-7) in children with acute respiratory infections (ARI) in China. HAdV-7-positive respiratory samples collected from children with ARI in Beijing, Shijiazhuang, Wenzhou and Guangzhou from 2014-2018 were selected for gene amplification and sequence analysis. Fifty-seven HAdV-7 clinical strains with hexon, penton base and fiber gene sequences were obtained. Meanwhile 17 strains were selected randomly from different cities for whole genome sequencing. Phylogenetic and variation analyses were performed based on the obtained sequences, HAdV-7 prototype strain Gomen (AY594255), vaccine strains (AY495969 and AY594256) and representative sequences of strains. The phylogenetic trees constructed based on whole genome sequences, major capsid protein genes (hexon, penton base and fiber) and the early genes (E1, E2, E3 and E4) were not completely consistent. The HAdV-7 strains obtained in this study always clustered with most of the circulating strains worldwide from the 1980s to the present. Compared with the HAdV-7 prototype strain Gomen (AY594255), some amino acid mutations in loop1 and loop2 of hexon and the RGD loop region of the penton base gene were observed. Recombination analysis showed that partial regions of 55 kDa protein and 100 kDa hexon-assembly associated protein genes among all HAdV-7 strains in this study were from HAdV-16 and HAdV-3, respectively. Our study demonstrated the molecular evolution characteristics of HAdV-7 strains circulating in China and provided basic reference data for the prevention, control and vaccine development of HAdV-7.

CYSLTR1 promotes adenoid hypertrophy by activating ERK1/2.

Cysteinyl leukotriene receptor 1 (CYSLTR1) serves a pivotal role in allergic reactions, which is one of the main causes of adenoid hypertrophy. The present study aimed to investigate the function of CYSLT1 within adenoid hypertrophy. A total of 40 patients with adenoid hypertrophy were recruited between January 2014 and January 2016 at the Children's Hospital of Hebei Province, China. The patients were divided into either the mild-moderate group or the severe group according to their disease severity. The expression of CYSLT1 in the adenoid tissue and whole blood of all patients and healthy controls was detected by reverse transcription-quantitative polymerase chain reaction. Associations between the expression level of CYSLT1 and the clinical characteristics of patients were analyzed. Primary human adenoid epithelial cells (HAECs) with CYSLT1 knockdown and overexpression were constructed. The levels of extracellular signal-regulated kinase (ERK)2 and phosphorylated-ERK1/2 in adenoid tissue and HAECs were detected by western blot analysis. The expression of CYSLT1 in adenoid tissue and whole blood of all patients with adenoid hypertrophy was significantly higher compared with the healthy controls (P<0.05). In addition, the expression level of CYSLT1 was significantly higher in the severe group compared with the mild-moderate group (P<0.05). The highest level of p-ERK1/2 in adenoid tissue was observed in the severe group, followed by the mild-moderate group and then the control group (P<0.05). CYSLT1 expression was positively associated with the severity of disease. CYSLT1 knockdown significantly decreased the level of p-ERK1/2 in HAECs (P<0.05), while CYSLT1 overexpression significantly increased the level of p-ERK1/2. It was concluded that CYSLT1 may contribute to the progression of adenoid hypertrophy by activating ERK1/2.

Genetic variations in the fusion protein of respiratory syncytial virus isolated from children hospitalized with community-acquired pneumonia in China.

To identify the variations in fusion (F) protein gene of RSV in China, a molecular epidemiological study was conducted. A total of 553 RSV positive specimens were collected from 2338 pediatric patients hospitalized with community-acquired pneumonia during a multi-center study conducted during 2014-2016. A total of 252 samples (183 RSV A, 69 RSV B) were selected for F gene sequencing, and analyzed together with 142 F gene sequences downloaded from GenBank. The result showed that all the Chinese RSV A and RSV B strains could be divided respectively into three branches. Compared with RSV A/B prototype sequences respectively, there were significant amino acid (AA) mutations at multiple antigenic sites. For RSV A, changes were found at AA residues 122, 124, 125, 276 and 384, and for RSV B at AA residues 45, 116, 125, 172, 173 and 202. Variations in human histocompatibility leukocyte antigen-restricted CTL epitopes were also observed. In total, 56 amino acid differences for the complete F protein were found between the RSV A and B groups in China, while several mutations were only found in the RSV B strains during 2015-2016. The RSV F gene is relatively conserved in China, however, limited mutations are still occurring with time.

[Detection of respiratory viruses in children with acute lower respiratory tract infection: an analysis of 5,150 children].

OBJECTIVE: To investigate the distribution of respiratory viruses on throat swabs in hospitalized children with acute lower respiratory tract infection (ALRTI). METHODS: A total of 5,150 children with ALRTI who were admitted to Hebei Children's Hospital between March 2014 and February 2015 were enrolled to investigate the distribution of respiratory viruses in children with ALRTI. Direct immunofluorescence assay was performed for throat swabs from these children to detect influenza virus A (FA), influenza virus B (FB), adenovirus (ADV), respiratory syncytial virus (RSV), and parainfluenza virus types 1, 2, and 3 (PIV-1, PIV-2, and PIV-3). RESULTS: Of all the 5,150 throat swabs from hospitalized children, 2,155 (41.84%) had positive virus detection results. RSV had the highest detection rate (1,338 cases/25.98%), followed by PIV-3 (439 cases/8.52%) and FA (166 cases/3.22%), and 29 patients had mixed infection with 2 viruses. With the increasing age, the detection rates of viruses tended to decrease (χ2=279.623; P<0.01). The positive rate of RSV increased gradually from September, and reached the peak value (60.09%) in November; the lowest positive rate occurred in June (1.51%). The positive rate of PIV-3 was the highest in May (21.38%) and the lowest in November (1.77%). CONCLUSIONS: The distribution of viruses in children with ALRTI varies with age and season, with RSV prevalence in autumn and winter and PIV-3 prevalence in spring and summer. RSV is the most common viral pathogen that causes ALRTI in hospitalized children.

[Prognostic judgment of children with Mycoplasma pneumoniae pneumonia associated with airway mucous plug formation].

OBJECTIVE: To investigate the clinical characteristics and treatment defects in slow-to-recover children with Mycoplasma pneumoniae pneumonia (MPP) associated with airway mucous plug formation, and to provide a basis for prognostic judgment and therapeutic guidance. METHODS: A retrospective analysis was performed on the clinical data of 67 children with MPP who were admitted between May 2012 and May 2014 and showed airway mucous plug formation in fiberoptic bronchoscope examinations. Based on the results of re-examinations using imaging methods, all patients were classified into a slow-to-recover group (n=30) and a control group (n=37). Comparisons of clinical outcomes, laboratory indices, imaging findings, and treatment methods were performed between the two groups. The receiver operating characteristic (ROC) curves were drawn to analyze the indices with significant differences. RESULTS: The percentage of neutrophils, levels of C-reactive protein (CRP), lactic dehydrogenase (LDH), fibrinogen (FIB), and IgM in peripheral blood, and incidence of pleural effusion were significantly higher in the slow-to-recover group than in the control group (P<0.05). The fever duration and treatment time of azithromycin and fiberoptic bronchoscope for the first time were significantly longer in the slow-to-recover group than in the control group (P<0.05). The results of ROC curve analysis showed that the optimal cut-off points of fever duration, percentage of neutrophils, levels of CRP and FIB, and treatment time of fiberoptic bronchoscope for the first time were 11.5 days, 70.7%, 57 mg/L, 4.7 g/L, and 13.5 days, respectively, with sensitivity and specificity higher than 0.643 and 0.727. CONCLUSIONS: The fever duration, percentage of neutrophils, level of CRP, level of FIB, and treatment time of fiberoptic bronchoscope for the first time can predict a recovery time longer than two months in children with MPP associated with mucous plug formation.

[Role of flexible bronchoscopy in the diagnosis and treatment of refractory pneumonia in children].

OBJECTIVE: To evaluate the effectiveness of the flexible bronchoscopy in the diagnosis and treatment of refractory pneumonia among children. METHODS: Sixty children with refractory pneumonia were randomly divided into two groups: lavage and control (n=30 each). The control group received conventional medical treatment. The lavage group was given flexible bronchoscopy besides conventional medical treatment. The therapeutic effects were compared between the two groups. The results of bacterial culture and detection of antibodies against Mycoplasma pneumoniae in bronchoalveolar lavage fluid (BALF) were observed. RESULTS: The coincidence of bacterial culture results between BALF and sputum samples was 63.3%, and there were no significant differences in the positive bacterial culture results between them. The coincidence of PCR test for antibodies against Mycoplasma pneumoniae between BALF and serum samples was 73.3%. The results of Fisher's exact test showed the positive rate of Mycoplasma pneumoniae antibodies of BALF was higher than that of serum (P<0.05). The effective rate in the lavage group was significantly higher than that in the control group (97% vs 73%; P<0.01). CONCLUSIONS: The flexible bronchoscopy is useful for the diagnosis and treatment of refractory pneumonia in children.

[Protection of mdr1 transfected cord blood mononuclear cell graft against anticancer agents in vivo].

OBJECTIVE: To explore the myelo-protection effect of mdr1 transfected cord blood cells (CBMNCs) graft against high-dose homoharringtonine leukemia-bearing severe combined immunodeficient (SCID) mice model. METHODS: Multidrug resistant (mdr1)gene was transferred into CBMNCs by a retrovirus vector, containing full-length cDNA of human mdr1 gene. CBMNCs and high-titer retrovirus supernatant were cocultured with cytokine combinations for 5 - 6 days. The SCID mouse models bearing human HL-60 cell leukemia were divided into three groups. Group A received tail vein injection of 2 x 10(6) mdr1 gene transduced CBMNCs at day 1 and 3, groups B and C 2 x 10(6) un-transduced CBMNCs and same volume of normal saline, respectively. The 3 groups of the mouse model were treated with weekly escalated doses of homoharringtonine. The peripheral white blood cell (WBC) counts, the human leukemia cells percentage in peripheral blood, the histological findings of main organs were assayed. The CD33 positive HL-60 cells in bone marrow were determined by flow cytometry. The function and expression of mdr1 gene were examined by PCR, immunochemistry (IC) and DNR extrusion test in vivo. RESULTS: (1) mdr1 gene was transferred into CBMNCs successfully and the transfection frequency was 30%. (2) Leukemia SCID mice were xenotransplanted with mdr1-transfected BMMNCs by a programmed procedure and could be used as a valuable model for in vivo evaluating myelo-protection effects. (3) The transfected mice could tolerate homoharringtonine 5 approximately 6 folds higher than conventional dose and kept peripheral WBC count at a mean of 3 x 10(9)/L, with the peripheral human myeloid leukemia cells percentage decreasing to less than 5%. Histological examination showed that there was no leukemia infiltration in the main organs, the CD33 positive HL-60 cells in bone marrow were less than 5%. (4) The repopulation frequency of the transfected CBMNs in marrow were 9.13%. DNR extrusion test confirmed that the P-gp product maintained its biological function in the marrow. CONCLUSION: mdr1 transferred-human CBMNC can xenotransplanted and repopulated in leukemia-bearing SCID mouse and are protected from chemotherapy-induced myelosuppression.

[Expression of Mdr1 gene in a murine bone marrow transplantation model].

OBJECTIVE: To investigate the expression of mdr1 gene in hematopoietic cells of a murine bone marrow transplantation model and to explore the feasibility of transferring mdr1 gene into hematopoietic cells to pro-vent myelosuppression from chemotherapy. METHODS: mdr1 gene was transferred into hematopoietic cells of murine bone marrow by retrovirus vector. The expression and function of mdr1 gene in vivo was tested in a murine bone marrow transplantation model. RESULTS: (1) mdr1 gene was successfully transferred into murine MNC, the transduction rate was 35%. (2) mdr1 gene transferred murine bone marrow transplantation model was established successfully by scheduled-bone marrow transplantation method. (3) In 1 approximately 5 months period, stable and effective expression of mdr1 gene could be detected in hematopoietic cells of the recipient mouse, the percentage of mdr1 gene expression cells in recipient's hematopoietic cells decreased monthly to 8.0%, 8.0%, 7.5%, 4.0% and 3.0%. (4) mdr1 expression hematopoietic cells had efficient resistance to chemotherapy. CONCLUSION: It is an effective approach to transfer mdr1 gene into hematopoietic cells for preventing myelosuppression in chemotherapy.