Objective To review the basic clinical characteristics and the pathogens and their antimicrobial susceptibilities to neonatal sepsis in very low birth weight infants (VLBWI) and extremely low birth weight infants ( ELBWI) for selection of appropriate antibiotics. Methods A retrospective chart review of 56 cases with neonatal sepsis(early onset neonatal sepsis 3 cases, late onset 53 cases) in VLBWI and ELBWI admitted to the neonatal intensive care unit of Yuying Children's Hospital of Wenzhou Medical College from January 1, 1999 to December 31, 2008 was conducted. The basic clinical characteristics and the results of blood culture and antimicrobial susceptibilities were analyzed. Results Among the 56 cases, the clinical presentations were non-specific. A total of 43 strains of bacteria were isolated, and the most important pathogens responsible for neonatal sepsis in VLBWI and ELBWI were opportunistic pathogenic bacteria. In early onset neonatal sepsis, there was only one culture-proven sepsis that was Chryseobacterium meningosepticum. In the late onset neonatal sepsis cases, the main pathogens of Gram-negative organisms were Klebsiella pneumoniae (33. 3%, 14/42), and the most common Gram-positive organisms were coagulase-negative Staphylococci (26. 2%, 11/42), followed by Enterococcus species (11. 9%,5/42). Furthermore, there were 2 fungal sepsis(4. 8%, 2/42), which were infected by Candida albicans. All of the coagulase-negative Staphylococci were methicillin-resistant coagulase-negative Staphylococci, and they were resistant to common antibiotics and sensitive to vancotnycin and rifampicin. And all of the Klebsiella pneumoniae produced extended-spectrum (Hactamases, which were sensitive only to a few antibiotics such as carbopenems, aminoglycosides and quinolones. Among those 56 cases, 43 patients were cured, 13 died, including six patients who refused any treatments, the mortality rate of neonatal sepsis in VLBWI and ELBWI was 23. 2%. Conclusions The clinical presentations of neonatal sepsis in VLBWI and ELBWI were non-specific, and the most important pathogens were opportunistic pathogenic bacteria, which were multi-drug resistant. Routine blood culture should be taken from infants who are suspected of neonatal sepsis and empirical use of appropriate antibiotics should be initiated as soon as the blood specimen for culture has been drawn. To reduce the occurrence of multi-drug resistant bacteria, we should restrict the use of antibiotics especially the third generation of cephalosporins in neonates as much as possible.

Objective:To assess the effect of Bolus materials(a material has the same effect with tissue)on dose distribution of electron beam radiotherapy on chest wall after surgery for breast cancer.Methods:Radiotherapy model of chest wall after modified radical mastectomy for breast cancer was constructed in this study.Based on the 6 MeV electron beam phase space file(PSF),which came from the International Atomic Energy Agency(IAEA)official website,and the Geant4 Monte Carlo software package,the research calculated the dose distributions of the electron beam radiotherapy of 5 kinds of different materials included water,polystyrene,polylactic acid,glycerol and silica-gel in Bolus materials,and compared the differences of the dose distributions between chest wall and lung tissue.Results:The Bolus materials have a relatively minor effect on the depth of maximum dose(dmax)of electron beams on the chest wall.The dmax maximum difference that was caused by Bolus with 10mm thickness only was 2mm.The Bolus materials with 10mm thickness have a notable effect on dose distribution,particularly in the posterior edge of the chest wall and shallow lung tissue.The order of Bolus materials corresponding to the dose in the posterior edge of the chest wall,from large to small,was polystyrene,water,polylactic acid,silica-gel and glycerol.For Bolus materials with 5 mm thickness and 10 mm thickness,the dose differences were approximate 8%and 15%,respectively.In shallow lung tissue,the corresponding Bolus materials with doses from large to small were water,polystyrene,polylactic acid,silica-gel and glycerol.For Bolus materials with 5 mm thickness and 10 mm thickness,the maximum dose differences were approximate 50%and 70%,respectively.Conclusion:The effect of Bolus materials has larger effect on the dose distribution of electron beam radiotherapy on the chest wall.The reasonable selection of Bolus materials is contributed to ensure the dose of target region,and minimize dose deposition of lung tissue.

Objective To analyze the influencing factors for intraventricular hemorrhage in the very low birth weight infants (VLBWI) and extremely low birth weight infants(ELBWI).Methods The clinical data of all VLBWI and ELBWI in the Second Hospital of Wenzhou Medical College from Jan.1,1999 to Dec.31,2011 were retrospectively collected.They were divided into the intraventricular hemorrhage (IVH) group and non-IVH group,which included mild and severe IVH in IVH group,and then the differences of perinatal factors were analyzed in the different groups.The severity of IVH was graded based on Papile classification,and SPSS 16.0 statistical software was used for the data processing and analysis.Results A total of 925 cases were collected,and the incidence rate of IVH was 12.6％ (117/925 cases),in which the severe IVH accounted for 58.4％ (66/113 cases).Factors like maternal hypertension,maternal age ≥ 30 years,gestational age,birth weight,male,small for gestational age,severe asphyxia,placental abnormalities (including placental abruption,placenta praevia,placenta adhesion,small placenta,aging of placenta),pneumonia,neonatal respiratory distress syndrome,pulmonary hemorrhage,invasive mechanical ventilation,using pulmonary surfactant (PS),chronic lung disease (CLD),necrotizing enterocolitis (NEC) were significantly different between 2 study groups (all P ＜ 0.05).Logistic regression analysis identified that gestational age ＜ 28 weeks (AOR 2.583 ; 95 ％ CI:1.357-4.916,P =0.004),maternal age ≥ 30 years (A OR 1.638 ; 95 ％ CI:1.061-2.530,P =0.026),invasive mechanical ventilation (AOR 2.098 ;95 ％ CI:1.262-3.488,P =0.004),NEC (A OR 3.064 ;95 ％ CI:1.391-6.750,P =0.005),using PS(AOR 1.794;95％ CI:1.057-3.045,P =0.030),pulmonary hemorrhage(AOR 3.372;95％ CI:1.138-9.989,P =0.028),subarachnoid hemorrhage (SAH) (AOR 4.936 ;95 ％ CI:1.717-14.184,P =0.003),periventricular leukomalacia(PVL) (AOR 3.157 ;95％ CI:1.294-7.701,P =0.012),hypoxic-ischemic brain damage (HIBD)(AOR 3.777;95％ CI:1.637-8.716,P =0.002) increased the risks of IVH.Invasive mechanical ventilation increased the risk of severe IVH(AOR 4.333 ;95％ CI:1.861-10.088,P =0.001).Conclusions Anong infants with birth weight ＜ 1 500 g,many prenatal,perinatal and postnatal factors are associated with incidence of IVH.Gestational age ＜ 28 weeks,maternal age ≥ 30 years,invasive mechanical ventilation,NEC,exogenous PS,pulmonary hemorrhage,SAH,PVL and HIBD are risk factors for IVH.Cranial ultrasound plays a key role in the early recognition of IVH.

Objective:To provide evidence for clinical diagnosis, prevention and control of group A rotavirus (RVA) diarrhea, the clinical characteristics of RVA diarrhea in children in Beijing from 2011 to 2018 were analyzed.Methods:From January 2011 to December 2018, 4 819 stool samples from children under 5 years old with diarrhea were collected monthly from 3 hospitals in Beijing. General information, clinical characteristics and other information of children were collected. RVA was detected by enzyme-linked immunosorbent assay (ELISA), genotype was identified by multiple semi-nested RT-PCR. The Vesikari clinical severity score was used to define the severity of diarrhea in children. Dichotomous unconditional logistic regression was used to analyze clinical symptoms and other differences between RVA positive and negative cases. Chi-square and Fisher direct probability tests were used to compare the composition among different groups.Results:A total of 4 819 fecal samples were collected, 953 were positive for RVA, the positive detection rate was 19.78%. The positive rate of RVA was high in the younger age group, and the incidence was high in winter and spring. RVA-positive children had more risk on diarrhea ≥5 times a day, vomiting symptoms, fever, mild dehydration, and Vesikari score ≥11. The positive rate of RVA in watery stool samples (26.13%, 214/819) and infectious diarrhea cases (42.20%, 265/628) was the highest respectively. There were no significant differences in clinical symptoms, clinical diagnoses and fecal traits among children with different RVA genotypes.Conclusions:The clinical symptoms of RVA diarrhea were severe in children. RVA genotype did not affect the clinical symptoms. Stool traits (watery stools) and Vesikari score can assist physicians in diagnosing RVA diarrhea.