ABSTRACT
Objective To investigate the mechanism of epidermal growth factor receptor-forkhead transcription factor A2 (EGFR-FOXA2) pathway-involved high secretion of mucus in human bronchial epitheli-um (HBE) cells after respiratory syncytial virus (RSV) infection and to evaluate the effects of intervention using agonist ( rosiglitazone ) and antagonist ( GW9662 ) of peroxidase proliferation activated receptor γ( PPARγ) and EGFR inhibitor ( AG1478 ) . Methods HBE cells were randomly divided into six groups: A group ( AG1478+RSV) , B group ( rosiglitazone+RSV) , C group ( GW9662+RSV) , D group ( RSV) , E group (0. 1％ dimethyl sulfoxide DMSO) and F group (HBE cell control group). Two hours before RSV infection, A, B and C groups were respectively treated with 10 μmol/L of AG1478, rosiglitazone and GW9662. Expression of EGFR, PPARγ and FOXA2 at mRNA level in each group was detected by real-time fluorescence quantitative RT-PCR 12 h, 24 h and 48 h after HBE cells were infected with or without RSV. Expression of phosphorylated-EGFR ( p-EGFR) and EGFR at protein level was detected by Western blot. ELISA was performed to measure the expression of mucin-5AC (MUC5AC). Results Compared with F group, EGFR expression at mRNA lev-el, p-EGFR/EGFR protein ratio and MUC5AC expression at protein level were increased in a time-dependent manner in A, B, C and D groups at 12 h, 24 h and 48 h. Compared with group F, the expression of PPARγat mRNA level in A, B, and D groups increased at each time point. Moreover, PPARγ expression gradually in-creased over time in A and B groups, reaching the peaks at 48 h, but was in decline in D group. Expression of FOXA2 at mRNA level in RSV-infected HBE cells was declined at each time point compared with that in group F, especially in D group. Compared with group D, A and B groups showed significantly decreased EGFR ex-pression at mRNA level, p-EGFR/EGFR protein ratio and MUC5AC expression at protein level, but markedly increased FOXA2 expression at mRNA level. Conclusions RSV infection increased the expression of MUC5AC at protein level in HBE cells. PPARγand EGFR-FOXA2 signaling pathways were involved in the hypersecretion of airway mucus during RSV infection.
ABSTRACT
Objective@#To study the epidemiology and antimicrobial resistance of Gram-negative bacterial bloodstream infections in children, and to guide the choice of antimicrobials and the control of nosocomial infection.@*Method@#Clinical data, bacteriology and antimicrobial susceptibility test results were collected retrospectively in hospitalized children who were diagnosed with gram-negative bacterial bloodstream infections in Yuying Children′s Hospital of Wenzhou Medical University from January, 2010 to December, 2015.@*Result@#A total of 399 cases (253 male and 146 female) were identified. The age ranged from 16 hours to 16 years (median age 10.1 months). The majority of cases were collected from division of neonatology (n=261, 65.4%), followed by 31 cases (7.8%) from pediatric intensive care unit and 29 cases (7.3%) from Gastroenterology Department; 275 cases (68.9%) had underlying diseases, mainly including preterm birth(n=172), neonatal respiratory distress syndrome(n=67) and newborn asphyxia(n=53). Eighty cases had received invasive procedures and 20 had surgical operation; 149 cases (37.3%) were community-acquired and 250 cases (62.7%) were hospital acquired. Fifty cases had complications, among those, 40 cases had septic shock, 32 cases had multiple organ dysfunction syndrome and 7 cases had disseminated intravascular coagulation; 288 cases were cured, 48 improved, 17 gave up treatment and discharged, and 46 died; totally 408 strains were isolated from 399 children, including Enterobacteriaceae (346, 84.8%), non-fermentative Gram-negative bacteria (49, 12.0%) and other gram-negative bacteria (13, 3.2%). The resistance rates of Escherichia coli (n=175) and Klebsiella pneumoniae (n=106) to carbapenems, β-lactams enzyme and its inhibitors, amikacin and cefoxitin were all lower than 10%. Totally 245 multi-drug resistant strains (60.1%) were isolated, including 225 strains of Enterobacteriaceae and 18 strains of non-fermentative Gram-negative bacteria (P<0.01) . Nine strains of Carbapenem-resistant Enterobacteriaceae were isolated, which were all sensitive to amikacin and the sensitive rates to fluoroquinolone reached 88.9%. Five strains which were detected sensitive to tigecycline were all sensitive. The proportion of Klebsiella sp in Gram-negative bacteria between 2013-2015 and 2010-2012 were 32.9% and 21.2%, respectively. The resistance rates of Escherichia coli and Klebsiella pneumoniae to β-lactams and its enzyme inhibitors and carbapenems had no significant change.@*Conclusion@#Gram-negative bacterial bloodstream infections occur more frequently in newborns. Most children had combined underlying diseases. Escherichia coli and Klebsiella pneumoniae are the most common pathogens. β-Lactams and its enzyme inhibitors and carbapenems are the empirical choice of antimicrobial therapy for severe Enterobacteriaceae bloodstream bacterial infections.