Blood culture and respiratory syncytial virus identification in acute lower respiratory tract infection

Even though the incidence of pneumonia in developed and developing countries is similar, the mortality is five times higher in developing countries. This study aimed to determine the prevalence of bacteremia in children with acute lower respiratory tract infection (LRTI) and relative contribution of respiratory syncytial virus (RSV). One hundred and one children under five years of age who attended a primary care level clinic with diagnosis of acute LRTI, were enrolled. Diagnosis and management of pneumonia were done according to the WHO guidelines. Two blood cultures were drawn at the time of admission. A nasopharyngeal sample was taken for detection of RSV by indirect immunofluorescence. Blood cultures were positive for pathogenic bacteria (Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus) in three patients. The detection for RSV was positive in 24 patients (23.7%). The clinical and radiographic presentations were not significantly different between patients with and without RSV (p > 0.05). RSV is a common cause of LRTI in children younger than five years old. Blood cultures are not commonly positive in outpatients with acute LRTI. The practice of obtaining blood cultures in primary and secondary care clinics is not useful to guide the treatment of patients with community-acquired pneumonia.     

��������С�������º������ϰ���������Ⱦ���ٴ��о�

目的 了解昆明地区呼吸道合胞病毒(RSV)在小儿急性下呼吸道感染中的发生率和临床特征.方法 对昆明市儿童医院2006年4月至2007年4月临床诊断为急性下呼吸道感染的住院患儿1112例行痰间接免役荧光法检测呼吸道合胞病毒抗原.结果 1112例标本中,阳性276例,阳性率24.82%,其中男190例(17.09%),女86例(7.73%),男女发病比例为2.21∶1.全年均可检出RSV,发生率最高的是10～12月份(30.15%),最低的是4～6月份(10.93%).RSV感染多见于3岁以下,尤以6个月以下患儿感染率最高(36.22%).结论 呼吸道合胞病毒是引起昆明地区小儿急性下呼吸道感染的主要病原,特别是婴幼儿感染率最高.     

婴儿急性下呼吸道感染与呼吸道合胞病毒、巨细胞病毒、肺炎支原体的关系

目的　探讨呼吸道合胞病毒 (RSV)、巨细胞病毒 (CMV)、肺炎支原体 (MP)的病原学特点及其与婴儿急性下呼吸道感染 (ALRI)的关系。方法　采用固相酶联免疫吸附法对ALRI婴儿联合进行血清RSV IgM抗体、CMV IgM抗体、MP IgM抗体进行定性检测。 结果　检测ALRI患儿 189例 ,单一病毒抗体阳性 10 6例(5 6 .0 9% ) ,RSV IgM抗体 5 7例 (30 .16 % )、CM IgM抗体 33例 (17.14 % )、MP IgM抗体 16例 (8.4 7% ) ,两种病原体混合感染 19例。RSV感染发生喘息 4 0例 (5 1.2 8% ) ,明显高于无喘息 (15 .32 % ) (P <0 .0 1)。CMV感染 2 8例喘息发生率显著高于无喘息 (P <0 .0 1)。两组MP感染率 (4.6 0 %和 11.76 % )差异无统计学意义。CMV感染中 5 7.5 8%肝功异常 ,胸片 5 4 .5 5 %呈间质性改变。结论　婴儿ALRI中RSV是其主要病原 ,易致喘息 ,CMV感染是小婴儿ALRI发生喘息的重要原因 ,常伴肝脏损害 ,MP感染率较低     

Airflow limitation during respiratory syncytial virus lower respiratory tract infection predicts recurrent wheezing

BACKGROUND: Respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) is frequently followed by recurrent wheezing. Thus far no clinical risk factors have been identified to predict which infants will have wheezing episodes subsequent to RSV LRTI. OBJECTIVE: To determine clinical predictors for airway morbidity after RSV LRTI. METHODS: In a 1-year follow-up study we investigated the predictive value of auscultatory findings characteristic of airflow limitation (wheezing) during RSV LRTI for subsequent airway morbidity. Clinical characteristics, including the presence or absence of signs of airflow limitation, of hospitalized infants with RSV LRTI were prospectively recorded during 2 winter epidemics. During a 1-year follow-up period parents of 130 infants recorded daily airway symptoms. OUTCOME MEASURE: Recurrent wheezing defined as > or = 2 episodes of wheezing. RESULTS: Signs of airflow limitation during RSV LRTI were absent in 47 (36%) infants and present in 83 (64%) infants. Recurrent wheezing was recorded in 10 (21%) infants without signs of airflow limitation and in 51 (61%) with signs of airflow limitation during initial RSV LRTI (relative risk, 0.29, P < 0.001). In a multiple logistic regression model, airflow limitation during initial RSV LRTI proved independent from other clinical parameters, including age, parental history of asthma and smoke exposure. CONCLUSIONS: A sign of airflow limitation during RSV LRTI is the first useful clinical predictor for subsequent recurrent wheezing.     

急性呼吸道感染儿童两亚型呼吸道合胞病毒检测分析

目的 了解2006-2007年度重庆地区住院急性呼吸道感染(ARTIs)儿童两亚型呼吸道合胞病毒(RSV)的感染特点及流行规律.方法 收集2006年4月至2007年3月全年在重庆医科大学附属儿童医院呼吸科住院的部分ARTIs患儿的鼻咽深部吸取物390份,针对RSV G基因保守区序列设计分型引物,采用RT-PCR方法检测标本中RSV的基因组RNA.结果 390例标本中RSV阳性例数为133例(133/390,阳性率为34.10%).阳性标本中A亚型阳性129例,B亚型阳性4例.RSV阳性患儿中,84.9%为2岁以下小儿.2006年11月～2007年1月为RSV高发季节,RSV检测阳性率为55.6%～62.3%,2006年12月RSV检测阳性率最高.B亚型出现于本地区RSV感染低发季节(4、5、6月).RSV感染的临床表现主要为发热(56.4%)、咳嗽(98.5%)、喘息(63.9%)、气促(76.7%)、紫绀(84.9%).临床诊断依次为毛细支气管炎(33.1%),支气管肺炎(27.8%),间质性肺炎(18.1%),重症肺炎伴呼吸衰竭(10.5%),喘息性支气管炎(5.3%),支气管哮喘(4.5%).结论 本研究初步阐明了重庆地区两亚型RSV感染的流行病学特点,证实RSV是重庆地区冬春季婴幼儿ARI的重要病原,2006-2007年度以A亚型RSV流行为主.今后的研究将纳入门诊及社区惠儿并进行多年度连续监测以进一步阐明重庆地区两亚型RSV流行规律及病毒进化特点.     

Equal virulence of rhinovirus and respiratory syncytial virus in infants hospitalized for lower respiratory tract infection

Respiratory syncytial virus (RSV) and rhinovirus (RV) are predominant viruses associated with lower respiratory tract infection in infants. We compared the symptoms of lower respiratory tract infection caused by RSV and RV in hospitalized infants. RV showed the same symptoms as RSV, so on clinical grounds, no difference can be made between these pathogens. No relation between polymerase chain reaction cycle threshold value and length of hospital stay was found.     

Phenotype of acute respiratory syncytial virus induced lower respiratory tract illness in infancy and subsequent morbidity

The objective of this study was to investigate the association hypothesis that outcome following respiratory syncytial virus (RSV) induced bronchiolitis (RSVB) and RSV induced wheeze (RSVW) are different. At 3 years respiratory symptoms were more common in those with RSV infection than the control group but there was no increase in allergic sensitisation (11% vs 10%). Those with RSVW were more likely to have evidence of allergic sensitisation when compared with RSVB subjects (22% vs 7%), and have increased symptoms and increased use of inhaled steroids. Conclusion: The data argue that RSV infection during infancy does not induce allergic asthma and that host factors rather than the virus determine long-term outcomes.     

Long-term consequences of respiratory syncytial virus (RSV) bronchiolitis

Despite differences in study design, follow-up studies consistently show that approximately half of the infants with respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) go on to have recurrent wheezing episodes during childhood. Respiratory symptoms are associated with abnormal lung function, including bronchial hyper-responsiveness. Wheezing symptoms following RSV LRTI gradually decrease, and it appears that during school age airway morbidity is no longer related to RSV LRTI during infancy. Mechanisms underlying the association between RSV LRTI and long-term airway morbidity are poorly understood. On the one hand, abnormal airway function that is congenitally present or acquired before RSV LRTI occurs could be the cause of both RSV LRTI and subsequent recurrent wheezing. On the other hand, it is possible that RSV LRTI causes changes in the lower airways or the immune system that result in long-term airway morbidity. Animal models suggest that RSV infection can promote the development of allergic sensitization, but most studies in humans do not indicate a role for atopy in the development of recurrent wheezing following RSV LRTI.     

下呼吸道感染患儿外周血单个核细胞呼吸道合胞病毒感染的研究

为探讨呼吸道合胞病毒（ＲＳＶ）对外周血单个核细胞（ＰＢＭＣ）的感染情况及感染后细胞免疫的变化，采用免疫组化法对１８例ＲＳＶ性急性下呼吸道感染患儿ＰＢＭＣ内ＲＳＶ及其Ａ、Ｂ亚型抗原进行了检测；采用ＡＰＡＡＰ法、ＭＴＴ比色法和ＥＬＩＳＡ法对Ｔ细胞亚群及Ｔ细胞表面白细胞介素２受体表达、ＰＢＭＣ培养上清液白细胞介素２（ＩＬ－２）活性和可溶性ＩＬ－２受体水平进行了测定。结果显示：１８例ＲＳＶ感染患儿中７例ＰＢＭＣ内可检测到ＲＳＶ抗原；１１例ＲＳＶＡ亚型感染者５例ＰＢＭＣ内均为ＲＳＶＡ亚型阳性，７例ＲＳＶＢ型感染者２例Ｂ亚型阳性；７例恢复期和１０例对照组患儿均为阴性；发病３天以内ＰＢＭＣ中ＲＳＶ抗原阳性者多于３天以后（Ｐ＜０．０５）。ＲＳＶ感染组ＰＢＭＣ内ＲＳＶ抗原阳性者，ＣＤ４细胞比率和ＩＬ－２水平均低于阴性者（ｔ＝２．３８，２．４０，Ｐ值均＜０．０５）。提示：ＲＳＶ性急性下呼吸道感染患儿ＰＢＭＣ可被ＲＳＶ感染，可能由此加重免疫活性细胞损害，导致细胞免疫功能紊乱。     

小儿下呼吸道感染的细菌病原学分析

目的：下呼吸道感染是造成儿童住院的最常见疾病之一。在发展中国家,病原菌以细菌感染相对多见,而病原菌的分布特点则常因年代不同而发生变迁。该研究的目的是了解本地区小儿下呼吸道感染常见病原菌及其对常用抗生素的耐药性,为临床药物治疗提供有价值的参考。方法：对2001年8月至2002年7月住院的所有下呼吸道感染患儿,常规进行深部痰培养,并用纸片扩散法、Etest法和Vitek系统进行药敏试验。结果：下呼吸道感染儿共4238例,其中1181例分离到1种或1种以上致病菌,阳性率为27.9%,最常见的病原菌为肺炎链球菌、流感嗜血杆菌、肺炎克雷伯菌、大肠埃希菌和金黄色葡萄球菌,分离率分别为5.2%,5.1%,5.1%,4.0%和2.1%。女性患儿肺炎链球菌的分离率显著高于男性(χ2=4.63,P<0.05),而肺炎克雷伯菌和金黄色葡萄球菌在男性中的分离率均高于女性(χ2=5.71,4.57,P<0.05)。年龄分布显示,1~3岁是肺炎链球菌和流感嗜血杆菌的好发年龄段,而肺炎克雷伯菌、大肠埃希菌、金黄色葡萄球菌和阴沟肠杆菌以及非常见菌感染则在1岁以内的婴儿中多见。季节分布上,12月份至3月份是大多数细菌感染分布较集中的时段。药敏结果显示青霉素不敏感肺炎链球菌、耐氨苄西林流感嗜血杆菌、耐苯唑西林金黄色葡萄球菌和产ESBL肺炎克雷伯菌、大肠埃希菌的比率分别为55.0%,16.5%,41.2%,42.6%和4.5%。结论：肺炎链球菌、流感嗜血杆菌、肺炎克雷伯菌、大肠埃希菌和金黄色葡萄球菌是小儿下呼吸道感染常见致病菌,但在不同年龄的感染率存在明显差异,治疗上应根据药敏结果选择敏感抗生素。     

双黄连雾化吸入治疗呼吸道合胞病毒所致急性下呼吸道感染

为评价双黄连雾化吸入对呼吸道合胞病毒（RSV）所致急性下呼吸道感染的疗效，采用双盲随机对照方法对45例3岁以下有RSV感染的肺炎或毛细支气管炎病例进行了治疗研究。双黄连组17例，病毒哩组和对照组各14例。结果表明，治疗后双黄连组及病毒唑组在症状体征缓解天数方面均短于对照组（F=5.12，P＜0．01）；血氧分压的改善双黄连组显著高于其他两组（F=4.31，P＜0．05）；肺部X线检查结果双黄连组也短于其他两组（H=11.01，P＜0．01）。双黄连组病毒检出率较低，细胞免疫指标恢复正常者亦较其他两组多。双黄连组未见任何严重副作用。研究结果提示，双黄连雾化吸入治疗RSV引起的下呼吸道感染是安全有效的方法。     

Etiology of acute lower respiratory tract infection

Objective : To identify pathogens responsible for acute severe lower respiratory tract infection (ALRTI) in under five children by non-invasive methods.Method : 95 children hospitalized with acute severe lower respiratory tract infection were investigated for identification of viruses, bacteria, chlamydia or mycoplasma by nasopharyngeal aspirates, blood culture and serology.Result : Etiological agents could be identified in 94% of the patients. Viruses from NP aspirate could be isolated in 36 (38%), bacterial isolates from blood cultures in 15(16%); mycoplasma was identified in 23(24%) and chlamydia in 10(11%) by serological tests; mixed infections were present in 8 (8%) patients.Conclusion : Noninvasive methods can be useful in identifying etiological agents in severe ALRTI     

Risk factors for severe respiratory syncytial virus-associated lower respiratory tract infection in children

BACKGROUND: Respiratory syncytial virus (RSV) is the most important cause of viral lower respiratory tract infection that can be a life-threatening disease in infants and children. This study was conducted to look for independent risk factors for severe respiratory syncytial virus-associated lower respiratory tract infection (RSV-LRI) that required oxygen supplementation or mechanical ventilation. METHODS: Medical records of patients younger than 4 years hospitalized with RSV-LRI at Shizuoka Red Cross Hospital from July 1, 1995 to June 30, 1999 were reviewed. The patients were compared using univariate and multivariate logistic regression analysis. RESULTS: A total of 157 patients were hospitalized with RSV-LRI at Shizuoka Red Cross Hospital from the study time period. Of these, 20 patients (12.7%) were diagnosed with severe RSV-LRI. Subjects younger than 3 months of age had an odds ratio (OR) of 59.9 (95% confidence interval (CI) 14.7_244.0) for the dependent variable of severe RSV-LRI (P<0.0001). Subjects with a history of congenital heart disease also had an OR of 99.2 (95% C1 8.5-1160.1) (P<0.0005). CONCLUSIONS: Infants younger than 3 months without any underlying diseases may be at high risk for severe RSV-LRI. Respiratory syncytial virus prophylaxis is needed not only for high-risk patients, but for healthy early infants.     

2004～2005年冬春季急性下呼吸道感染患儿RSV亚型的检测及分析

目的分析2004～2005年冬春季呼吸道合胞病毒(RSV)流行季节的亚型分布情况。方法采用直接免疫荧光法检测2004年10月～2005年4月间因急性下呼吸道感染住院儿童1040例鼻咽部分泌物中的常见病毒病原,随机选择RSV阳性标本174例,采用间接免疫荧光检测RSVA、B亚型,分析检测结果。结果1040例中,RSV阳性497例(47.8%),其中174例标本中,检测出RSVA亚型23例(13.2%),B亚型105型(60.4%),A、B亚型混合感染36例(20.7%),无法确定亚型的10例(5.7%)。检测期间各月份间、不同的年龄组间和临床诊断间的RSV亚型分布差异均无显著性意义(P>0.05),都以B亚型为主。结论2004～2005年冬春季RSV仍是儿童急性下呼吸道感染的主要病原,以B亚型为主;并有两种亚型同时感染的情况。