Effect Of Positive Nasopharyngeal S.p Culture On Children With RSV Pneumonia And Itsmechanism

PART I ANALYSIS OF CLINICAL FEATURES IN CHILDREN WITH RSV PNEUMONIA COMPLICATED WITH NASOPHARY-NGEAL S.P CULTURE POSITIVEObjective:RSV is the most common viral pathogen causing lower respiratory tract infection in infants and young children.Streptococcus pneumoniae(S.p)is one of the most frequently detected nasopharyngeal pathogens in infants.A retrospective analysis of the demographic characteristics of RSV pneumonia combined with nasopharyngeal S.p culture positive would provide a scientific theoretical basis for further exploring the mechanism of interaction between the two pathogens and prevention of mixed infectious diseases of the two pathogens in children.Methods:Children with pneumonia whose age ?36 months old were included which were further divided into<12 month old and 13-36 month old groups.According to the results of previous nasopharyngeal aspirate virology and bacterial culture,the results were divided into RSV,S.p and RSV+S.p detection groups.The clinical datas of children were collected,including general data,current medical history,personal history,family history,clinical symptoms,auxiliary examination,diagnosis,treatments and so on.Results:1.The demographic characteristics and clinical manifestations of children with RSV,S.p and RSV+S.p were obvious different:the airway inflammatory indexes of the nasopharynx S.p positive group(S.p group and RSV+S.p group)and the systemic inflammatory response were significantly higher than that of the negative group,and the more smaller age,the more significant the difference.2.Compared with RSVB+S.p group,the positive rate of severe pneumonia was significantly higher in the RSVA+S.p group.Conclusion:The clinical manifestations of children with RSV or RSV combined with S.p were found to be different,especially in children younger than 1 year old.PART II DIFFERENCES AND MECHANISMS IN THE PENICI-LLIN RESISTANCE OF NASOPHARYNX S.P IN CHILDREN WITH RSVA/RSVB PNEUMONIAObjective:It is known that RSV and S.p co-infection is through the binding of G protein of RSV to the penicillin-binding protein 1A of S.p,then significantly enhancing the invasiveness of S.p.G protein is an important protein of RSVA and RSVB subtypes;PBP1A is a target of ?-lactam antibiotics such as penicillin,whose amino acid site mutation is an important factor affecting the resistance.By further exploring the differences in the resistance of RSVA/RSVB co-detection with S.p and the possible mechanism,it would provide an important theoretical basis for prevention and treatment of mixed pathogenic diseases of the two pathogens in clinical.Methods:Children who were<36 months old with NPA detection of RSVA+S.p,RSVB+S.p and S.p pneumonia were included.The resistance of S.p to penicillin and the amino acid mutations of PBP1 A,PBP2B and PBP2X in each group were analyzed.Results:1.Comparision between RSVA+S.p and RSVB+S.p groups,the resistance of S.p to penicillin was significantly different.2.Comparision among amino acid site mutations in STMK?SSN?KT/SG of PBP1 A,PBP2B and PBP2X in S.p,RSVA+S.p and RSVB+S.p groups were not obvious in penicillin-sensitive,intermediate and drug-resistant groups.PBP1A catalytically active center has multiple amino acid sites in the opening crack amino acid site:AT392I,P407VY,T420LQ,D473KK,T495YY,H503KV,S517NV,D533MM had different mutation trends in RSVA+S.p and RSVB+S.p groups.Conclusion:Compared between the RSVA+S.p and RSVB+S.p groups,the resistance to penicillin was significantly enhanced.There were significant different trends in the distribution of multiple mutations at the fracture opening of the PBP1A catalytic activity center in RSVA+S.p and RSVB+S.p groups.PART III DIFFERENCES IN NASOPHARYNGEAL S.P SEROTYPE DISTRIBUTION AND BACTERCIAL GENUS CHARACTERISTICS IN CHILDREN WITH RSV+S.P PNEUMONIAObjective:RSV is the most common viral pathogens in children less than 1 year old,which is closely related to the pathogenesis of asthma.Studies have shown that bacterial composition of NPA in bronchiolitis children with RSV and HRV infection were quite different.Analyze the S.p serotypes distribution and the characteristics of NPA bacteria in children RSV+S.p pneumonia is important for further explore the pathogenesis of children with RSV+S.p and provide important theoretical basises.Methods:Children who were RSV/HRV pneumonia combined with nasopharynx S.p detection and age ?12 month were included.The serotypes were detected both by mPCR and sequencing.18 NPAs of RSV+S.p and 12 NPAs of HRV+S.p were randomly selected for 16SrDNA detection to understand the genus of NPA bacteria.Results:1.RSV was often detected together with 19F S.p,and there was a significant difference compared with HRV group.2.The composition of NPA bacteria genus in children with RSV+S.p and HRV+S.p pneumonia is mainly Streptococcus by 16SrDNA,Haemophilus and Moraxella genus were also account for large proportion.Three species in two groups were no significant difference;the other genus of bacteria were relatively low.Conclusion:The NPA bacteria in RSV+S.p/HRV+S.p groups were significantly different from RSV/HRV group,and the bacteria may play a more important role in the former groups.The relationship between RSV/HRV and S.p serotypes is different.There may be new relationships between virus and bacteria or pathogen subtypes.