A族链球菌的随机扩增片段长度多态性DNA分型

目的为了深入了解Ａ族链球菌（ＧＡＳ）感染的菌型分布情况。方法采用随机扩增ＤＮＡ多态性（ＲＡＰＤ）方法，对北京儿童医院１９９３～１９９４年间分离的８７株临床来源ＧＡＳ菌株及１６株标准菌株进行ＲＡＰＤ分析。结果所有菌株均能得到扩增条带，分型率较浊度分型（ＯＦ）分型法高；共发现３１种不同带型，且同一Ｍ型菌株可有不同ＲＡＰＤ型；化脓性扁桃腺炎与猩红热的ＧＡＳ菌株ＲＡＰＤ型分布有明显差异（Ｐ＜０．０１）；半数（１６／３２）猩红热来源ＧＡＳ株为Ｒ１２型。结论ＲＡＰＤ方法在ＧＡＳ流行病学及对ＧＡＳ分型研究中有一定的应用价值，并提示此一时期北京儿童医院猩红热病人中有Ｒ１２型菌株流行。     

河南省汝阳县婴幼儿流行性喘憋性肺炎暴发流行的病原学研究

目的：了解１９９９年１１月－２０００年１月我国河南省汝阳县婴儿流行性喘憋性肺炎（简称流喘肺炎）暴发流行的病原,方法：分别采用１２例流喘肺炎患儿的咽拭子和算咽分泌物标本进行病毒分离,间接免疫荧光检测常见的呼吸道病毒抗原以进行快速诊断,用ＲＴ－ＰＣＲ对分离到的呼吸道合孢病毒（ＲＳＶ）株进行分型,１６例用免疫荧光法检测双份血清中ＲＳＶ抗体滴度,用核苷酸序列测定对分离到的病朱进行基因分析,结果：１２例患儿咽拭子标本中（险１例污染外）４例分离到ＲＳＶ,阳性率为３６％,３例为Ａ亚型,１例为Ｂ亚型,１２例算咽分泌物脱落细胞经免疫荧光法检测９例为ＲＳＶ阳性,阳率性为７５％,未检测到其它呼吸道病毒,１６例患儿双份血清中,有１０例（６３％）恢复期血清ＲＳＶ特异性ＩgG抗体比急性期有４倍以上升高,分离株Ｆ蛋白基因的部分序列测定显示与ＲＳＶ的Ａ型型标准株有高的同源性。结论：此次婴幼儿流喘肺炎流行的病原主要为Ａ型型ＲＳＶ。     

应用逆转录聚合酶链反应鉴别呼吸道合胞病毒亚型

目的为了使鉴别呼吸道合胞病毒（ｒｅｓｐｉｒａｔｏｒｙｓｙｎｃｙｔｉａｌｖｉｒｕｓ，ＲＳＶ）Ａ、Ｂ亚型的方法更为简单、特异、有效。方法根据ＲＳＶＧ蛋白编码基因的核苷酸序列设计一套引物，其中Ｐ１为亚型间通用的引物，Ｐ２和Ｐ３分别为Ａ、Ｂ亚型特异性引物。将这些引物用于同一逆转录聚合酶链（ＲＴＰＣＲ）反应，Ａ、Ｂ亚型株的扩增产物分别为２７７ｂｐ和８６３ｂｐ，根据ＰＣＲ产物的大小即可鉴别所测毒株的亚型。用这一方法对ＲＳＶ原型株和９株我国分离株进行亚型鉴定。结果分离株８株为Ａ亚型，１株为Ｂ亚型，分型结果与单克隆抗体检测和基因序列分析完全相符。结论ＲＴＰＣＲ方法鉴别呼吸道合胞病毒亚型具有快速、简便、敏感、特异等特点，适用于ＲＳＶ临床标本的亚型分型及流行病学研究     

婴幼儿肺炎病毒病原与流行病学观察：附52例报告

本文应用ＥＬＩＳＡ法对５２例肺炎患儿进行ＲＳＶ，ＰＦＶ（１，２，３型）和ＡＤＶ（３，７型）特异型抗体检测，阳性２４例（阳性率４６．２％），以ＰＦＶ居首（占２７％），其中ＰＦＶ３和ＰＦＶ１分别占１３．５％和９．６％；ＲＳＶ次之占（占１１．５％）。三种病毒感染主要发生在３岁以内小儿，以１岁以下婴儿发病率最高（占６６．７％）。１２月－１月为流行高峰（占７０．８％）。     

肺炎支原体肺炎患儿细胞免疫的研究

采用ＡＰＡＡＰ法和ＥＬＩＳＡ法对３５例肺炎支原体肺炎（ＭＰＰ）患儿急性期和恢复期外周血Ｔ淋巴细胞亚群（ＣＤ３、ＣＤ４、ＣＤ８）及血清可溶性白细胞介素－２受体（ｓＩＬ－２Ｒ）进行测定。ＭＰＰ患儿急性期和恢复期ＣＤ４、ＣＤ４／ＣＤ８比值均明显低于对照组（Ｐ均＜０．０１）；ＣＤ８明显高于对照组（Ｐ均＜０．０５）；ＣＤ３与对照组无显著性差异。在ＭＰＰ的急性期和恢复期，ｓＩＬ－２Ｒ水平明显高于对照组（Ｐ均＜０．０１）。急性期ＣＤ８、ＣＤ４与ｓＩＬ－２Ｒ水平呈高度正、负相关。提示Ｔ淋巴细胞功能的紊乱及ｓＩＬ－２Ｒ水平的改变与ＭＰＰ的发生密切相关。     

肺炎和腹泻患儿亚临床维生素A缺乏的研究

为探讨肺炎和腹泻患儿体内维生素Ａ（ＶＡ）状况及其与疾病的关系，对１２８例肺炎、１１６例腹泻患儿和１００名健康儿童测定血清ＶＡ，其均值分别为１．１±０．５μｍｏｌ／Ｌ，０．８±０．４μｍｏｌ／Ｌ和１．９±０．６μｍｏｌ／Ｌ（Ｆ＝１４６．６７０，Ｐ＜０．０１）。对其中６０例肺炎、８５例腹泻患儿进行ＶＡ的相对剂量反应（ＲＤＲ）测定，其ＲＤＲ均值分别为２２％±１９％，２３％±１０％，亚临床ＶＡ缺乏（ＰＶＡＤ）检出率分别为４３．３％，６１．２％。发病１，２～４，５～７天即入院的肺炎、腹泻患儿在入院次日所测的ＲＤＲ均值和ＰＶＡＤ检出率均相近（肺炎患儿的Ｈｃ＝２．５６０，χ２＝０．２６２，Ｐ均＞０．０５；腹泻患儿的Ｈｃ＝０．２２９，χ２＝０．５１０，Ｐ均＞０．０５）。在诊断肺炎、腹泻患儿ＰＶＡＤ时，均以ＲＤＲ法检出率为高。提示：肺炎、腹泻患儿血清ＶＡ水平低于健康儿童，约半数的患儿体内处于ＰＶＡＤ状态。在发病７天内体内ＶＡ水平不受病程影响。评价体内ＶＡ状况以ＲＤＲ法更为敏感可靠。     

合胞病毒感染儿童淋巴细胞多种表面标记及细胞因子的初步研究

呼吸道合胞病毒（ＲＳＶ）感染发病机理的研究一直受到重视，研究者发现ＲＳＶ感染患儿存在着一系列免疫功能紊乱。本文用ＡＰＡＡＰ技术对ＲＳＶ感染患儿淋巴细胞ＣＤ３、ＣＤ４、ＣＤ８、ＣＤ２３、ＣＤ２５、ＣＤ５７、ＩＦＮｒ、ＨＬＡ－ＡＢＣ、ＨＬＡ－ＤＰ和ＨＬＡ－ＤＲ等表面标记进行检测，并用ＥＬＩＳＡ技术检测血浆中白细胞介素２（ＩＬ－２）、可溶性白细胞介素２受体（ｓＩＬ－２Ｒ）和呼吸道合胞病毒特异性ＩｇＥ（Ｒ     

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。     

婴幼儿肺炎的鼻咽分泌物免疫球蛋白测定

本文应用间接免疫荧光技术快速诊断法检测３岁以下婴幼儿肺炎的呼吸道脱落细胞（ＮＰＳ）中的合胞病毒（ＲＳＶ）及腺病毒（ＡＤＶ）。并对其中ＲＳＶ感染２１例、ＡＤＶ感染９例、两者均阴性３８例共６８例肺炎患儿的ＮＰＳ作免疫球蛋白（ＩｇＧ，ＩｇＡ）含量的测定。结果表明，３组肺炎患儿ＮＰＳ中的ＩｇＧ，ＩｇＡ含量均明显低于正常对照组（Ｐ分别为＜０．０１，＜０．０５），而各组肺炎之间无显著差异（Ｐ均＞０．０５）。     

肺表面活性剂治疗新生儿呼吸衰竭的疗效分析

为评价肺表面活性剂（ＰＳ）治疗ＲＤＳ和重症肺炎的疗效，本文对１２例接受ＰＳ治疗的新生儿ＲＤＳ和重症肺炎病例进行分析。结果显示：治疗组患儿在病程不同时期的ａ／ＡＰＯ２均明显高于对照组（Ｐ均＜０．０５），肺部并发症的发生率低于对照组，机械通气时间、需氧时间及住院时间均明显短于对照组（Ｐ均＜０．０５）。治疗组患儿的存活率为７５％，对照组为３７％，两组比较，差异显著（Ｐ＜０．０５）。提示：ＰＳ治疗能有效地改善新生儿ＲＤＳ和肺炎患儿的肺氧合功能，减少肺部并发症的发生，缩短病程     

Horizontal transmission of group B streptococcus in a neonatal intensive care unit

The incidence of early-onset group B streptococcal (GBS) sepsis in the neonatal population has decreased substantially since the introduction of maternal intrapartum antibiotic prophylaxis and routine prenatal screening. However, these strategies have not reduced the incidence of late-onset GBS infections. Additional research pertaining to the transmission of late-onset GBS infections is required to develop effective preventive methods. The present report describes probable horizontal transmission of late-onset GBS infection among three infants in a neonatal intensive care unit. GBS strain confirmation was based on the microbiological picture, antibiogram and pulsed-field gel electrophoresis. These cases highlight the morbidity associated with late-onset GBS disease and the importance of considering horizontal transmission as an etiological factor in GBS infection in the newborn period. Further studies assessing horizontal transmission in late-onset GBS disease may improve prevention and early intervention.     

Late-onset neonatal group B streptococcal disease associated with breast milk transmission: molecular typing using RAPD-PCR

Group B Streptococcus (GBS) is considered to be the major cause of neonatal sepsis and meningitis of bacterial origin. Late-onset GBS infection is infrequent and occurs between 1 week and 3 months of age. The transmission of GBS through the ingestion of breast milk is reported in the literature, but only a few of these cases have been confirmed by molecular techniques. In this article we report five cases of late-onset GBS disease: transmission through maternal milk was confirmed in four cases, using the random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) typing assay. In addition, the RAPD-PCR assay showed that each of the isolated clones belonged to a different RAPD genotype, thus revealing that the late-onset GBS infections were not epidemiologically related.     

Group B streptococcal carriage and disease: a 6-year prospective study

A prospective study of group B streptococcal (GBS) carriage and disease was conducted over 6 years. Carriage rates at delivery for mothers and infants were 20% and 12%, respectively. Forty-five cases of GBS disease occurred in infants, 24 "early-onset" disease and 21 "late-onset" disease. The combined attack rate for early and late disease was 3.3 per 1000 live births over the 6 years. The rate of early-onset disease was highest in infants found to be heavily colonized at birth: 50 per 1000 live births. Twenty-three of 24 had evidence of intrauterine-acquired infection. All GBS serotypes were represented. Preterm delivery, prolonged labor, premature rupture of membranes, and maternal infection enhanced the risk of early disease. Septicemia was the predominant form of late-onset disease (15 of 21 cases); GBS type III accounted for 19 of 21 cases. Ten of 21 infants with late infections were colonized at birth with the GBS type that subsequently caused disease. Thus a maternal source of infection was identified in 34 of the 45 infants. These data reveal consistent year-to-year carriage and disease rates in the study population.     

Late-onset and Recurrent Neonatal Group B Streptococcal Disease Associated with Breast-milk Transmission

The purpose of the study was to determine the epidemiological relationships in three unrelated cases of neonatal late-onset Group B streptococcal (GBS) disease and maternal breast-milk infection with GBS. All deliveries were by cesarean section; case 1 was at term, and cases 2 and 3 were at 32- and 33-wk gestation, respectively. Case 1 relates to a mother with clinical mastitis and recurrent GBS infection in a 20-day-old male infant. Following antibiotic therapy and cessation of breast-feeding, the infant recovered without sequelae. Case 2 refers to a mother with clinical mastitis and the occurrence of late-onset GBS disease in 5-wk-old male twins. Despite intervention, one infant died and the second became ill. Following antibiotic therapy and cessation of breast-feeding, the surviving infant recovered without sequelae. Case 3 refers to a mother with sub-clinical mastitis and late-onset GBS infection occurring in a 6-day-old female twin. Following intervention, the infant recovered but suffered a bilateral thalamic infarction resulting in developmental delay and a severe seizure disorder. Following recovery of GBS from an inapparent mastitis and cessation of breast-feeding, the second infant remained well. Blood cultures from all affected infants and maternal breast milk were positive for GBS. Epidemiological relationships between neonatal- and maternal-derived GBS isolates were confirmed by a random amplified polymorphic DNA polymerase chain reaction assay (RAPD-PCR). This study is significant in that it has demonstrated that maternal milk (in cases of either clinical or sub-clinical mastitis) can be a potential source of infection resulting in either late-onset or recurrent neonatal GBS disease.     

新生儿B族链球菌感染预防策略的研究进展

B 族链球菌可引起新生儿早发型和晚发型疾病,主要危险因素是母亲胃肠道和生殖道的定植。目前对存在危险因素的妊娠妇女有两种筛选方案：高危因素评估方案和普遍筛查方案;美国等国家采取产时抗生素预防性治疗措施,使早发型B 族链球菌疾病的发病率大幅度降低,但对晚发型疾病的发病率影响不大。抗生素预防性治疗首选青霉素,对青霉素过敏者需依据菌株药敏结果选择药物。抗生素预防性治疗措施存在一定的弊端,需积极研发其他的预防措施来预防B 族链球菌感染。     

Neonatal escherichia coli infections: concerns regarding resistance to current therapy

Currently recommended antibiotic treatment of suspected neonatal sepsis is ampicillin and an aminoglycoside. Recently, we observed increasing ampicillin and gentamicin resistance in strains of Escherichia coli isolated from neonates at our institution. We therefore reviewed clinical and laboratory records of all neonates with systemic infection, hospitalized from 1994 through 1998, from whom E. coli was isolated from blood and/or cerebrospinal fluid. The influence of perinatal variables (e.g. rupture of foetal membranes > 24h, group B Streptococcus (GBS) colonization, urinary tract infection during pregnancy and the use of antepartum and/or intrapartum antibiotics), and neonatal variables (e.g. gestational age, age at onset of sepsis (early: < or = 72 h, late: >72 h), number of E. coli septic recurrences, and associated underlying medical and/or surgical conditions) on antimicrobial susceptibilities of invasive E. coli isolates was studied. Twenty-three neonates with invasive E. coli infection were identified; most [19 (83%)] presented as late-onset sepsis (LOS). Ampicillin-resistant E. coli were isolated in 75% and 53% of neonates in the early- and late-onset groups, respectively. Gentamicin resistance was found in 50% of early-onset sepsis (EOS) isolates compared with 16% in the late-onset group. Isolates from two neonates with EOS were resistant to both ampicillin and gentamicin. One neonate with EOS and three with LOS had recurrent E. coli sepsis; all isolates were ampicillin-resistant and one was gentamicin-resistant. All these neonates were initially treated with ampicillin and gentamicin. Both groups had associated underlying medical and/or surgical conditions (50% early-onset, 47% late-onset). Maternal GBS colonization occurred in 2 (50%) versus 3 (16%) of EOS and LOS cases, respectively. All GBS colonized women received intrapartum ampicillin prior to delivery. CONCLUSIONS: Ampicillin and gentamicin resistance is emerging in neonatal E. coli isolates from invasive infection. Current- empiric management of neonatal sepsis requires re-evaluation given changing antimicrobial susceptibilities.     

Infections in the NICU: Neonatal sepsis

Neonatal infections remain an important cause of neonatal morbidity and mortality worldwide. Neonatal sepsis is a systemic infection that can be classified as early-onset or late-onset pending the timing of presentation. The pathophysiology and causative pathogens of neonatal sepsis vary, with early-onset sepsis being associated with a vertically transmitted infection from mother to neonate versus late onset sepsis being commonly associated with nosocomial infections. The signs and symptoms of neonatal sepsis mimic those associated with prematurity, making timely diagnosis difficult for treating clinicians. The management of neonatal sepsis is centered around obtaining adequate culture data and initiation of broad-spectrum parenteral antibiotics. Controversies surrounding the management of neonatal sepsis include the administration of empiric antibiotics, given recent clinical studies associating early antibiotic use with clinical sequelae such as late-onset sepsis, necrotizing enterocolitis, and death in the preterm, low-birthweight infant population.     

Perinatal infection with Group B streptococci

Group B streptococcus (GBS) is a major cause of severe bacterial infection in newborns. Early neonatal GBS infection can be prevented by identifying high-risk pregnancies and administering intrapartum antibiotics. In the USA, a screening strategy has been introduced resulting in a reduction in early-onset GBS infection, but no decrease in late-onset neonatal GBS disease has been noted. In many European countries, a risk-based strategy is recommended. Vaccination may, in the future, be an alternative in preventing GBS infection in newborns.     

Late-onset neonatal infections: incidences and pathogens in the era of antenatal antibiotics

Widespread use of intrapartum antimicrobial prophylaxis has significantly reduced the incidence of early-onset neonatal infection (EONI); however, little is known about the effects of increased maternal exposure to antibiotics on late-onset neonatal infection (LONI). This study aims to evaluate LONI epidemiology in our region after the application of French recommendations and to determine whether LONI-causing organisms and their antibiotic susceptibility are influenced by peripartum antibiotic exposure. We performed a prospective epidemiologic study of 139 confirmed and possible cases of bacterial LONI in patients treated with antibiotics for at least 5 days of the 22,458 infants born in our region in the year 2007. The overall incidence of LONI caused by all pathogens, Group B streptococcus (GBS) and Escherichia coli (E. coli) were 6.19, 0.36 and 2.72, respectively, per 1,000 live births. Our findings revealed three major types of LONI: E. coli-induced urinary tract infection (UTI) among term infants, coagulase negative Staphylococcus septicemia affecting preterm infants, and GBS infections with severe clinical presentation. Univariable analysis revealed that maternal antibiotic exposure was significantly associated with the risk of amoxicillin-resistant E. coli infection (p = 0.01). Postnatal antibiotic exposure was associated with an increased risk of E. coli LONI (p = 0.048). This link persisted upon multivariable analysis; however, no additional risk factors were identified for LONI caused by antibiotic-resistant E. coli. CONCLUSION: Our findings confirm that despite the benefits of antenatal antibiotics, this treatment can increase the risk of antibiotic-resistant cases of LONI. National and international surveillance of LONI epidemiology is essential to assess benefits and potential negative consequences of perinatal antibiotic exposure.     

B族链球菌的红霉素耐药基因研究

目的 比较不同地区B族链球菌（GBS）对红霉素耐药性的差异及耐药基因谱特点。方法 用琼脂稀释法，测定红霉素、克林霉素对不同地区（北京，广州，俄罗斯圣彼得堡）的113株GBS的最低抑菌浓度（MIC），同时用PCR和核酸杂交的方法，检测红霉素耐药基因mreA、mefA、ermA、ermB、ermC在该批菌株中的出现规律及其与红霉素耐药性的关系。结果 （1）北京、广州两地GBS菌株总耐药率为46％，与克林霉素耐药性的一致率为93．8％；所有ermA基因均来自北京菌株，而广州菌株不含该基因。（2）含ermA和（或）ermB基因的GBS占所有菌株的30．09％，其耐药率高达97．06％，在已检测的GBS菌株中未发现ermC基因。（3）分别有53株和18株含mreA和mefA的GBS以及1株含ermA的菌株仍对红霉素敏感。2株GBS不含上述任何一种基因，但仍对红霉素耐药。结论 （1）北京、广州两地GBS对红霉素普遍具有较高的耐药率，且与大环内酯－林可霉素－链阳性霉素B类抗生素之间存在较严重的交叉耐药，临床使用抗生素时应尽量避免重复选择此类抗生素；（2）ermA和ermB是决定我国北京、广州GBS对红霉素耐药的重要基因；（3）GBS的耐药性还有其他分子生物学机制参与。