白芍粗提物及芍药苷对变异链球菌作用的体外实验

目的 研究白芍粗提物及其主要成分芍药苷对变异链球菌的作用。 方法 采用醇提法制取白芍粗提物,通过高效液相色谱法测定白芍粗提物的主要活性成分,分别观察白芍粗提物及其主要成分芍药苷在不同药物浓度下对变异链球菌的粘附、产酸、合成水不溶性胞外多糖以及葡聚糖转移酶(GTF)比活力等方面的影响。 结果 白芍粗提物及芍药苷对变异链球菌的体外生长最小抑菌浓度(MIC)分别为3.130和1.770 mg/mL,当两者的浓度分别为≥1.565和≥0.885 mg/mL时,有明显的抑制变异链球菌粘附、合成水不溶性胞外多糖和GTF比活力的作用(P<0.05); 当白芍粗提物浓度为3.130 mg/mL时,有明显的抑制变异链球菌产酸的作用(P<0.05),而不同浓度的芍药苷对变异链球菌产酸均无影响(P>0.05)。不同浓度白芍粗提物组和芍药苷组的水不溶性胞外多糖含量和GTF比活力之间均呈正向直线相关。 结论 白芍粗提物可抑制变异链球菌的粘附、产酸、合成水不溶性胞外多糖和GTF活性,其主要活性成分芍药苷可抑制变异链球菌的粘附、合成水不溶性胞外多糖和GTF活性,但不影响变异链球菌的产酸活动。     

Treatment strategies for central nervous system infections: an update

Introduction: Central nervous system infection continues to be an important cause of mortality and morbidity worldwide. Our incomplete knowledge on the pathogenesis of how meningitis-causing pathogens cause CNS infection and emergence of antimicrobial resistance has contributed to the mortality and morbidity. An early empiric antibiotic treatment is critical for the management of patients with bacterial meningitis, but early recognition of bacterial meningitis continues to be a challenge.

Areas covered: This review gives an overview on current therapeutic strategies for CNS infection with a focus on recent literature since 2010 on bacterial meningitis. Bacterial meningitis is a medical emergency, requiring early recognition and treatment. The selection of appropriate empiric antimicrobial regimen, after incorporating the epidemiology of bacterial meningitis, impact of vaccination, emergence of antimicrobial-resistant bacteria, role of adjunctive therapy and the current knowledge on the pathogenesis of meningitis and associated neuronal injury are covered.

Expert opinion: Prompt treatment of bacterial meningitis with an appropriate antibiotic is essential. Optimal antimicrobial treatment of bacterial meningitis requires bactericidal agents able to penetrate the blood–brain barrier, with efficacy in cerebrospinal fluid. Emergence of CNS-infecting pathogens with resistance to conventional antibiotics has been increasingly recognized, but development of new antibiotics has been limited. More complete understanding of the microbial and host factors that are involved in the pathogenesis of bacterial meningitis and associated neurologic sequelae is likely to help in developing new strategies for the prevention and therapy of bacterial meningitis.     

Increasing postpartum rate of vaccination with tetanus,diphtheria, and acellular pertussis vaccine by incorporating pertussis cocooning information into prenatal education for group B streptococcus prevention

BackgroundTo evaluate whether incorporating pertussis cocooning information into prenatal education for group B streptococcus (GBS) prevention increased postpartum rate of vaccination with tetanus, diphtheria, and acellular pertussis (Tdap) vaccine.MethodsWe performed a retrospective pre-intervention/post-intervention study of postpartum women at a teaching hospital in Taiwan. We compared the frequency of Tdap vaccination during the pre-intervention (May 1, 2009 to December 31, 2010) and post-intervention (March 1, 2011–March 31, 2012) time periods. The clinical intervention was incorporation of pertussis cocooning information into prenatal education for GBS prevention to pregnant women presented during a prenatal visit at 35–37 weeks of gestation. Postpartum Tdap vaccination rate during the pre-intervention and post-intervention periods was compared. We also specifically examined group differences in the percentage of women who received postpartum Tdap vaccination to explore factors that influenced their decision regarding Tdap vaccine.ResultsTdap vaccination was more likely during the post-intervention period compared with the pre-intervention period (2268 of 3186 [71.2%] compared with 2556 of 5030 [55.6%]; p < .001). Comparisons between each subgroup of pre-intervention and post-intervention women showed that incorporating pertussis information into prenatal education for GBS prevention was beneficial except for women of maternal age 30–34 years and women living in rural areas.ConclusionsPrenatal GBS screening activities represent an opportunity for healthcare providers to offer pertussis cocooning information to eligible pregnant women to improve rates of postpartum Tdap vaccination.     

Lewis大鼠急慢性期风湿性心脏炎模型的比较研究

【摘要】 目的 比较3种急慢性期风湿性心脏炎模型,找出理想的动物模型。方法 抗原Ⅰ、Ⅱ分别为灭活溶血性链球菌(GAS)与完全弗氏佐剂（CFA）、不完全弗氏佐剂（IFA）混合的乳化剂。 Lewis雌鼠随机分成四组：实验A、B、C组首次后足垫注射0.2mL抗原Ⅰ,随后分别注射抗原Ⅰ、Ⅱ、未灭活GAS免疫刺激建立模型,对照组D组分别对应ABC组各6只,GAS替换为生理盐水免疫刺激。于第7、12、24周末处死每组各6只,行血液生化及心脏HE染色检查。结果C组死亡率25%;A组心脏炎发生率最高,12周A、C组急性期损伤心肌、瓣膜弥漫性炎症细胞浸润,心肌间质风湿细胞聚集,较B组明显;24周慢性期损伤A组瓣膜纤维化程度及比率较B、C组高;D组心肌、瓣膜均无病理改变。结论 A组CFA与GAS1：1混合乳化剂免疫大鼠5次,之后GAS连续刺激,能为急慢性期风湿性心脏病的实验研究提供较好的可复制的动物模型。     

Group A streptococcal meningitis in a pediatric patient

A case of group A streptococcal meningitis is reported in a 14-year-old girl with a history of recurrent otitis media. She presented to the emergency room with an altered level of consciousness; the organism was isolated from her spinal fluid and blood. Her course was complicated by a left-sided sinus vein thrombosis with extension to the external jugular vein, which has previously been reported in the literature only once. Streptococcus pyogenes is a common cause of invasive infections, but is a highly uncommon cause of meningitis.     

Phlegmonous gastritis associated with HIV-1 seroconversion

Summary A 40-year-old man presented with peritonitis. Diagnosis of phlegmonous gastritis was made by laparotomy. Conservative treatment combined with antibiotics was successful. Multiple endoscopies with biopsies illustrate the natural history of this disease. The patient developed HIV-1 seroconversion during hospital stay. Prompt diagnosis and treatment may improve the prognosis of this often lethal disease.     

Diagnostic accuracy of rapid nucleic acid tests for group A streptococcal pharyngitis: systematic review and meta-analysis

BackgroundAcute pharyngitis is one of the most common conditions in outpatient settings and an important source of inappropriate antibiotic prescribing. Rapid antigen detection tests (RADTs) offer diagnosis of group A streptococcus at the point of care but have limited sensitivity. Rapid nucleic acid tests (RNATs) are now available; a systematic review of their accuracy is lacking.ObjectivesTo evaluate the accuracy of RNATs in patients with pharyngitis; to explore test-level and study-level factors that could explain variability in accuracy; and to compare the accuracy of RNATs with that of RADTs.Data sourcesMEDLINE, Embase, Web of Science (1990–2020).Study eligibility criteriaCross-sectional studies and randomized trials.ParticipantsPatients with pharyngitis.Index test/s and reference standardsRNAT commercial kits compared with throat culture.MethodsWe assessed risk of bias and applicability using QUADAS-2. We performed meta-analysis of sensitivity and specificity using the bivariate random-effects model. Variability was explored by subgroup analyses and meta-regression.ResultsWe included 38 studies (46 test evaluations; 17 411 test results). RNATs were most often performed in a laboratory. The overall methodological quality of primary studies was uncertain because of incomplete reporting. RNATs had a summary sensitivity of 97.5% (95% CI 96.2%–98.3%) and a summary specificity of 95.1% (95% CI 93.6%–96.3%). There was low variability in estimates across studies. Variability in sensitivity and specificity was partially explained by test type (p < 0.05 for both). Sensitivity analyses limited to studies with low risk of bias showed robust accuracy estimates. RNATs were more sensitive than RADTs (13 studies; 96.8% versus 82.3%, p 0.004); there was no difference in specificity (p 0.92).ConclusionsThe high diagnostic accuracy of RNATs may allow their use as stand-alone tests to diagnose group A streptococcus pharyngitis. Based on direct comparisons, RNATs have greater sensitivity than RADTs and equal specificity. Further studies should evaluate RNATs in point-of-care settings.     

变异链球菌乳酸脱氢酶与霍乱毒素B亚单位嵌合表达质粒的构建和表达

目的:构建含变异链球菌乳酸脱氢酶(LDH)和霍乱毒素B亚单位(CTB)嵌合原核表达质粒,并诱导表达融合蛋白。方法:应用PCR技术扩增LDH编码基因ldh和CT编码基因ctxB,定向克隆至原核表达质粒pET32a(+)上,通过限制性内酶切、PCR和序列测定分析鉴定后转化大肠杆菌BL21(DE3),并经IPTG诱导表达融合蛋白。结果:PCR扩增得到了ldh和ctxB;构建的质粒pET-LDH/CTB经KpnⅠ、XhoⅠ双酶切和目的基因PCR检测,均得到1.4 kb大小的片段,与预计目的基因片段大小相同;质粒pET-LDH/CTB中插入的ldh序列与GeneBank中ldh比较同源性为98%,ctxB的同源性达99%,插入的相位正确;经IPTG诱导表达了约70×103的蛋白。结论:成功构建了变异链球菌LDH和CTB嵌合表达质粒pET-LDH/CTB,并正确表达融合蛋白。     

高果糖玉米糖浆致龋性的动物实验研究

目的:通过观察大鼠进食含高果糖玉米糖浆(high fructose corn syrups,HFCS)饲料后牙齿的患龋情况,评价HFCS的致龋性.方法:选择适龄SPF级远交群大鼠(Spraque-Dawley,SD)30只,抑制口腔固有菌群后接种变异链球菌UA159,并随机分为3组,分别用不含糖饲料、含蔗糖饲料和含HFCS饲料喂养3个月.3个月后截取上下颌骨,体视显微镜观察磨牙颊舌面龋损;制作磨牙纵磨片,荧光染色后用荧光显微镜观察(牙合)面和邻面龋损情况,并根据Keyes评分法评价龋损程度.结果:3组大鼠的患龋率均为100％.HFCS组与蔗糖组的龋损程度无统计学差异(P＞0.05);蔗糖组各牙面的龋齿记分均显著高于不含糖饲料组(P＜0.05);HFCS组中,窝沟龋全层、平滑面龋釉质和牙本质外层1/4的龋齿记分均明显高于不含糖饲料组(P＜0.05),而平滑面龋损深度超过牙本质厚度1/4的龋齿记分与不含糖饲料组比较无统计学差异(P＞0.05).结论:含HFCS的饮食能导致SD大鼠发生龋病,其龋损程度与蔗糖相近.