幽门螺杆菌中国菌株致病相关基因cagA、iceA、vacA及HP0519分布分析

目的分析中国不同人群及不同胃部疾病病例来源的幽门螺杆菌致病相关基因cagA、iceA、vacA及HP0519的分布.方法采用特异引物聚合酶链式反应（PCR）方法分析150株幽门螺杆菌上述基因的多态性分布特点,并对其分布作初步统计分析.结果93%（139/150）中国菌株cagA基因3′端重复序列的PCR产物具有东方菌株特征.75%（113/150）菌株iceA基因为iceA1,19%（29/150）为iceA2,不同地区间iceA基因的分布差异无统计学意义.云南菌株iceA1、iceA2的分布与菌株分离个体的种族特点及临床疾病类型无显著关系.96%中国菌株（144/150）vacA基因s区的等位基因为s1;m区等位基因m2、m1b和m1b-m2的比例分别为57%（85/150）、27%（41/150）和11%（16/150）,仅2株福建菌株为m1a.不同地区间vacA s1、m2、m1b分布的差异无统计学意义.云南菌株m1b-m2的分布高于福建和北京菌株.云南菌株vacA s区等位基因的多样性与分离个体的种族及临床疾病类型无显著关系.vacA m区等位基因的多样性与分离个体的临床疾病类型无显著关系,但不同民族间m2的分布有显著差异,白族人群m2的分布显著少于汉族和纳西族.93%（140/150）的中国菌株HP0519基因具有24 bp和15 bp DNA插入和缺失的多态性特点.不同地区间HP0519基因的多态性无显著不同.云南菌株HP0519的多态性与菌株分离个体的临床疾病类型无显著关系,但来源不同民族菌株的HP0519基因存在差异.结论幽门螺杆菌中国菌株cagA 3′端JF/TR特异引物的扩增结果具有东亚菌株特点.中国菌株vacA基因多为s1,其分布与菌株分离个体的临床疾病类型无关.中国菌株vacA基因m区的分布具有多样性.中国菌株HP0519基因具有24 bp和15 bp插入和缺失的多态性特点.     

结核分枝杆菌利福平耐药基因rpoB突变特征初步分析

目的 阐明结核分枝杆菌利福平耐药株rpoB基因突变特点。方法 对110株结核分枝杆菌临床分离株包括rpoB基因利福平耐药决定区（RRDR）81个碱基在内的286bp片段进行聚合酶链反应．单链构象多态性（PCR．SSCP）分析，并对经检测显示有突变的结核分枝杆菌rpoB基因此扩增区域进行序列测定。其中利福平耐药株73株，非利福平耐药株11株，敏感株26株。结果 PCR—SSCP检测显示利福平耐药株中有47株有突变存在，经直接测序分析其中76．6％的菌株存在rpoB基因的单位点突变，主要集中在531位（61．1％）和526位（25．0％）；联合突变发生率为23．4％。此外，经PCR—SSCP检测，11株非利福平耐药株中2株有突变存在，26株敏感株中1株有突变存在。经直接测序分析突变涉及位点为511位、526位和535位。结论 rpoB基因耐药决定区发生突变是结核分枝杆菌利福平耐药的主要原因，其中531位丝氨酸和526位组氨酸是最常见的突变位点。     

吉林省汉城型汉坦病毒基因分型研究

目的 查明吉林省褐家鼠中汉城型汉坦病毒的基因亚型及其分布情况。方法 在吉林省的主要疫区采集啮齿类宿主动物，用免疫荧光法检测鼠肺标本，对汉坦病毒抗原阳性标本以RT-PCR法扩增部分M和S基因片段上的核苷酸序列并测序，将扩增片段的核苷酸序列与已知病毒序列进行系统发生分析并分型。结果 褐家鼠携带的汉坦病毒均为汉城病毒。序列分析发现在吉林省主要疫区褐家鼠流行的汉城病毒均为S3亚型，与辽宁、黑龙江省褐家鼠中的病毒株同源性较高，进化关系较近。结论 吉林省褐家鼠主要携带S3亚型的汉城型汉坦病毒。     

肠道常见病原菌检测基因芯片的制备与评价

目的建立并评价快速准确地检测肠道致病菌的基因芯片检测方法。方法在基因芯片制备基础上，通过对靶基因的扩增、杂交和对杂交结果的分析，对常见肠道致病菌的检测和鉴定效果进行评价。结果应用包含38种特异性探针的基因芯片，对涉及沙门菌、志贺菌、霍乱弧菌、致泻性大肠埃希菌、空肠弯曲菌、小肠结肠炎耶尔森菌、副溶血弧菌和单核细胞李斯特菌等8个菌属的16株致病菌进行检测，均得到特异性杂交图谱。结论制备的基因芯片能够同时检测多种重要的肠道致病菌，为肠道致病菌感染的快速诊断提供了准确、快速、灵敏的方法。     

PCR技术在赫坎按蚊复合体近缘种鉴别中的应用

目的应用聚合酶链反应（PCR）技术分析湖北省不同地区媒介按蚊的种型.方法采用传统的形态学方法和新建立的基因鉴别技术对现场捕获的按蚊分别进行形态特征鉴别和基因鉴别及比较.结果现场捕获181只按蚊,形态学确认176只为中华按蚊,而PCR鉴定172只为中华按蚊,另4只为八代按蚊;经形态学特征鉴别的5只嗜人按蚊中,PCR鉴别有4只为嗜人按蚊,另1只为八代按蚊.结论采用PCR基因鉴别技术能准确鉴别赫坎按蚊种团内中华按蚊、嗜人按蚊、八代按蚊等近缘种按蚊,较传统的按蚊形态学鉴别方法准确,适用于复合媒介地区的疟疾媒介调查和监测.     

How cost effective is switching universal vaccination from PCV10 to PCV13? A case study from a developing country

BackgroundChildren immunization with pneumococcal conjugate vaccine (PCV) had profound public health effects across the globe. Colombian adopted PCV10 universal vaccination, but PCV incremental impact need to be revalued. The objective of this analysis was to estimate the cost-effectiveness of switch to PCV13 versus continue PCV10 in Colombian children.MethodsA complete economic analysis was carried-out assessing potential epidemiological and economic impact of switching from PCV10 to PCV13. Epidemiological information on PCV10 impact was obtained from lab-based epidemiological surveillance on pneumococcal isolates at the Colombian National Institute of Health. Economic inputs were extracted from the literature. Incremental PCV13 effectiveness was based in additional serotypes included. Comparisons among alternatives were evaluated with the Incremental Cost-Effectiveness Ratio (ICER) at a willingness to pay of one GDP per capita (USD$ 6631) per Year of Live Saved (YLS). All costs were reported in 2014USD. Deterministic and probabilistic sensitivity analyses were performed, and 95% confidence interval reported.ResultsAfter four years using PCV10 for universal vaccination on children the Colombian health surveillance system showed a relative increment on non PCV10 isolates. To change from PCV10 to PCV13 would avoid 587 (CI95% −49–1008) ambulatory Rx community-acquired pneumoniae (CAP), 1622 (CI95% 591–2343) Inpatient RxCAP, 10 (CI 95% 6–11) pneumococcal meningitis, and 79 (CI95% 76–98) deaths. ICER per YLS was USD$ 2319 (CI95% Dominated – USD$ 4225) for Keep-PCV10 and USD$ 1771 (CI95% USD$ 1285–9884) for Switch-to PCV13. In spite of its cost-effectiveness Keep-PCV10 is an extended dominated alternative and Switch-to PCV13 would be preferred. Results are robust to parameters changes in the sensitivity analyses.ConclusionA national immunization strategy based in Switch-to PCV13 was found to be good value for money and prevent additional burden of pneumococcal disease saving additional treatment costs, when compared with to Keep-PCV10 in Colombia, however additional criteria to decision making must be taken into account.     

Characteristics of pediatric invasive pneumococcal diseases and the pneumococcal isolates in Suzhou,China before introduction of PCV13

BackgroundData on characteristics of invasive pneumococcal diseases (IPD) is limited in China. We aimed to understand the clinical features and explore the molecular characteristics of the pneumococcal isolates in China.MethodsSince 2010, we prospectively collected the pneumococcal isolates and the IPD patients’ demographic and clinical information in Suzhou University Affiliated Children’s Hospital (SCH). The antibiotic susceptibility, serotypes, genotypes of Streptococcus pneumoniae strains were identified by E-test, quellung reaction and/or multiplex PCR, and multi-locus sequence typing, respectively.ResultsDuring the period from January 2010 to December 2015, a total of 80 IPD patients were identified. They were diagnosed as meningitis (31.3%), septicemia (27.5%), pneumonia (21.3%) and others (20.0%). About half of them required vancomycin treatment, 42.5% were admitted to ICUs, 36.2% had complications and 6.2% were hospitalized for over 1 year. The most common serotypes of the pneumococcal isolates were serotypes 6B and 14, the coverage of PCV13 was 92.5%, and CC236s and CC199s were the most common clone complexes.ConclusionsPediatric IPD patients had severe clinical symptoms, demanded intensive treatment, suffered poor prognosis and substantial burden. The pneumococcal isolates’ serotype coverage of PCV13 vaccine was high, which leads to implication of PCV vaccine usage among children in China.     

Association between hypertensive disorders complicating pregnancy and risk of placenta accreta: a meta-analysis and systematic review

Objective: Previous studies have reported a positive association between hypertensive disorders complicating pregnancy and placenta accreta. However, whether hypertensive disorders complicating pregnancy associated with placenta accreta is still not clear. The objective was to systematically review the literature to determine a possible association between hypertensive disorders complicating pregnancy and placenta accreta. Methods: A systematic search of PubMed database, the Cochrane Library, Willy Online Library, and ScienceDirect database through 1st December 2015, was conducted. Two authors independently assessed data extraction and quality of the studies using the Newcastle-Ottawa Scale. Assessment of heterogeneity and analysis of data were operated by Review Manager 5.3.0. Results: Three studies involving 4174 patients who developed hypertensive disorders complicating pregnancy of a total of 38,004 pregnant women were selected. The result of our meta-analysis revealed that pregnancy induced hypertension was significantly associated with a reduction of placenta accreta (OR = 0.50, 95% CI: 0.30–0.82; heterogeneity: I² = 13%, p = 0.32). Conclusions: Our meta-analysis demonstrated that the risk of placenta accreta is reduced in women with hypertensive disorders complicating pregnancy. Further well-designed studies are warranted to testify the result and explored any potential mechanism association between hypertensive disorders complicating pregnancy and placenta accreta.     

Effect of prior vaccination on carriage rates of Streptococcus pneumoniae in older adults: A longitudinal surveillance study

IntroductionPneumococcus is a commensal of the upper respiratory tract and colonization is common in young children. Carriage studies have provided insights on vaccine effects in children and may also be useful for assessing vaccines in adults. However, culture based prevalence studies in older adults describe low colonization rates. Therefore, we assessed cumulative incidence of pneumococcal colonization in older adults using polymerase chain reaction (PCR) targeting the lytA gene and risk factors for carriage.Methods100 community-dwelling adults ≥65 years were enrolled the winter of 2015 and followed biweekly for 12 months. Medical, vaccination and illness history as well as nasopharyngeal (NP) and oropharyngeal (OP) samples were collected. Combined OP and NP were incubated in enrichment broth and screened using real-time lytA PCR. Samples from new colonization events (lytA PCR+) were cultured on gentamicin blood agar plates. Isolates identified by colony morphology as S. pneumoniae were serotyped using a multiplex combined immunoassay-PCR platform which classifies 96 serotypes. Cumulative incidence of pneumococcal carriage was calculated and risk factors for carriage assessed.ResultsThe cumulative incidence of colonization was 41% by PCR and 14% by culture. Monthly prevalence ranged from 0 to 17% by PCR and 1 to 4% by culture with peaks in the spring and fall. Demographics were similar between colonized and never colonized subjects although colonized were younger (72.4 vs. 75.0 years, P = 0.06). Vaccination with any pneumococcal vaccine before or during study period was associated with decreased risk of becoming colonized (p < 0.001) as was vaccination with either the 13-valent conjugated pneumococcal vaccine (PCV13) or 23-valent polysaccharide vaccine (PPSV23) (p < 0.001).ConclusionPneumococcal colonization in older adults as detected by lytA PCR is frequent and pneumococcal vaccination appears to be associated with decreased risk of carriage. Further study is needed to understand the biological significance of molecular detection of pneumococcus in adults.