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Plastic bronchitis (PB) constitutes a life-threatening pulmonary disorder, predominantly attributed to Mycoplasma pneumoniae (MP) infection. The pathogenic mechanisms involved remain largely unexplored, leading to the absence of reliable approaches for early diagnosis and clear treatment. Thus, the present investigation aimed to develop an MP-induced mouse model of PB, thereby enhancing our understanding of this complex condition. In the first stage, healthy BALB/c mice were utilized to investigate the optimal methods for establishing PB. This involved the application of nebulization (15–20 min) and intratracheal administration (6–50 μL) with 2-chloroethyl ethyl sulfide (CEES) concentrations ranging from 4.5% to 7.5%. Subsequently, the MP model was induced by administering an MP solution (2 mL/kg/day, 108 CFU/50 μL) via the intranasal route for a duration of five consecutive days. Ultimately, suitable techniques were employed to induce plastic bronchitis in the MP model. Pathological changes in lung tissue were analyzed, and immunohistochemistry was employed to ascertain the expression levels of vascular endothelial growth factor receptor 3 (VEGFR-3) and the PI3K/AKT/mTOR signaling pathway. The administration of 4.5% CEES via a 6 µL trachea was the optimal approach to establishing a PB model. This method primarily induced neutrophilic inflammation and fibrinous exudate. The MP-infected group manifested symptoms indicative of respiratory infection, including erect hair, oral and nasal secretions, and a decrease in body weight. Furthermore, the pathological score of the MP+CEES group surpassed that of the groups treated with MP or CEES independently. Notably, the MP+CEES group demonstrated significant activation of the VEGFR-3 and PI3K/AKT/mTOR signaling pathways, implying a substantial involvement of lymphatic vessel impairment in this pathology. This study successfully established a mouse model of PB induced by MP using a two-step method. Lymphatic vessel impairment is a pivotal element in the pathogenetic mechanisms underlying this disease entity. This accomplishment will aid in further research into treatment methods for patients with PB caused by MP. [ABSTRACT FROM AUTHOR]

Objective: To investigate the molecular epidemiological characteristics of norovirus (NoV) among children with acute gastroenteritis in Tianjin in 2017., Methods: A total of 758 stool specimens were collected from the children with acute gastroenteritis possibly caused by viral infection in Tianjin Children's Hospital between January and December, 2017. Quantitative real-time RT-PCR was used for primary screening of NoV, and conventional RT-PCR was used for gene amplification, sequencing and genotype identification of the VP1 region of capsid protein in positive specimens., Results: Among the 758 specimens, 241 (31.8%) were found to have GII NoV. Sequencing of the VP1 region of capsid protein in positive specimens showed that among the 241 specimens with GII NoV, 69 (28.6%) had GII.4 subtype, 51 (21.2%) had GII.3 subtype, 24 (10.0%) had GII.2 subtype, and 18 (7.5%) had other subtypes. There was a significant difference in NoV detection rate between different age groups (P=0.018), and the 1- <4 years group had the highest NoV detection rate (37.3%). There was also a significant difference in NoV detection rate across seasons (P<0.001), and there was a highest NoV detection rate in winter (48.1%). Twenty-seven children (3.6%) had co-infections with NoV and rotavirus., Conclusions: NoV is one of the major pathogens of the children with acute gastroenteritis from Tianjin in 2017. GII genotype, especially GII.4 subtype, is the prevalent strain. NoV infection is commonly seen in children less than 4 years and reaches the peak in winter. Some children are found to have co-infections with rotavirus.

Objective: This study aimed to summarize the clinical characteristics and antimicrobial resistance of carbapenem-resistant Acinetobacter baumannii (CRAB) infections in children, identify its risk factors and to raise the level of diagnosis and treatment of this disease., Method: The data of clinical and antimicrobial susceptibility of 32 cases of CRAB and 64 cases of carbapenem-susceptible Acinetobacter baumannii (CSAB) infections as control seen between January 1, 2004 and December 31, 2010 in Yuying Children's Hospital Affiliated to Wenzhou Medical College were analyzed retrospectively., Result: Thirty-two cases of CRAB infections were identified, 21 were male and 11 female. The ages ranged from 1 day to 16 years (median age 43 days) ,among whom 14 (44%) were aged < or = 28 days; 28 cases (88%) were diagnosed as hospital-acquired pneumonia (HAP) and 4 cases (12%) had wound infection. The common primary diseases of the cases were neonatal respiratory distress syndrome (n = 12, 38%), followed by congenital heart disease (n = 5,16%) and open fractures (n = 5,16%). Before the isolation of CRAB, 10 cases (31%) had received major surgery;29 patients (91%) had stayed in ICUs, 26 cases (81%) had received tracheal intubation and mechanical ventilation,the ventilation time was 2 -249 days (median: 12 days). Carbapenem was used in 17 cases (53%) previously, 13 (41%) had received beta-lactam/beta-lactamase inhibitor combinations, 8 (25%) had used 3rd-generation cephalosporins within 2 weeks before the isolation of CRAB. Sixteen cases (50%) were cured, 12 cases (38%) were improved, parents of 1 case(3%) automatically gave up hospitalization without being cured and 3 cases (9%) died. Forty-nine CRAB strains were isolated from the 32 cases, accounting for 10. 4% of AB isolation strains in the same period, in which 40 strains (82%) were isolated from sputum specimens and 9 strains (18%) from open wounds secretions. All 49 strains showed multidrug-resistance (MDR), of which 13 strains (27%) were pandrug-resistant (PDR) to the common antimicrobials. The rates of resistance to ampicillin-sulbactam and cephalosporins were 90% and more than 85%, respectively; while the rates of resistance to cefoperazone-sulbactam were 19%, the lowest among the tested agents. In multivariate analysis, receiving surgery (OR = 8.450), tracheal intubation and mechanical ventilation for more than 10 days (OR = 6.366) and previous use of carbapenems (OR = 7.084) were independent risk factors for CRAB infections., Conclusion: Nosocomial infections in children due to CRAB infections mainly cause HAP and open wound infection. Previous surgery, prolonged tracheal intubation and mechanical ventilation for more than 10 days and previous carbapenems therapy within 2 weeks before the isolation of CRAB were independent risk factors for CRAB infections. CRAB showed MDR or even PDR to the common antimicrobials, which made great difficulties in antibiotic choices.