In vitro activity of xanthorrhizol against Streptococcus mutans biofilms

AIMS: We determined the effect of xanthorrhizol (XTZ) purified from the rhizome of Curcuma xanthorrhiza Roxb. on the Streptococcus mutans biofilms in vitro. METHODS AND RESULTS: The biofilms of S. mutans at different phases of growth were exposed to XTZ at different concentrations (5, 10 and 50 micromol l(-1)) and for different time exposures (1, 10, 30 and 60 min). The results demonstrated that the activity of XTZ in removing S. mutans biofilm was dependent on the concentration, exposure time and the phase growth of biofilm. A concentration of 5 micromol l(-1) of XTZ completely inhibited biofilm formation by S. mutans at adherent phases of growth, whereas 50 micromol l(-1) of XTZ removed 76% of biofilm at plateau accumulated phase when exposed to S. mutans biofilm for 60 min. CONCLUSIONS: Xanthorrhizol isolated from an edible plant (C. xanthorrhiza Roxb.) shows promise as an antibacterial agent for inhibiting and removing S. mutans biofilms in vitro. SIGNIFICANCE AND IMPACT OF THE STUDY: XTZ could be used as a potential antibacterial agent against biofilm formation by S. mutans.     

猪链球菌2型全基因组DNA芯片的研制及基因表达谱技术平台的建立

目的：研制猪链球菌2型（SS2）全基因组DNA芯片,建立SS2基因表达谱技术平台。方法：利用SS2全基因组序列,挑选出2194条基因,经PCR扩增出2156条基因并将产物纯化,点样制备芯片;将芯片用于表达谱研究,采用实时定量PCR验证表达谱结果,对芯片进行可靠性分析。结果：芯片杂交数据与实时定量PCR验证显示了较高的相关性,二者相关系数r=0.87。结论：研制了一批SS2全基因组DNA芯片,并建立了基于DNA芯片的表达谱技术平台。     

Gene expression profile in immunologically injured liver cell of mice

To study the gene expression profiles between immunologically injured liver cell and normal liver cell of mice and to screen on a large scale the differentially expressed genes associated with the formation of liver injury, the experimental mice were randomly divided into the normal group for controlling and the immunologically liver-injured group induced by BCG and LPS. The liver mRNA of the two groups were extracted respectively and reversely-transcribed to cDNA with the incorporation of different fluorescence (Cy3, Cy5) labeled dUTP as the hybridization probes. The mixed probes were hybridized to the cDNA microarray chips. The fluorescent signal results were acquired by scanner ScanArray 4000 and analyzed with software GenePix Pro 3.0. Among the 14112 target genes, 293 genes were found to be significantly differentially expressed, in which 188 genes were up-regulated and 105 genes were down-regulated. Based on the analysis of biological functions of those differentially expressed genes, it was indicated that the occurrence and development of mouse liver damage induced by BCG and LPS were highly correlated with the processes of immune reactions, cell synthesis, metabolism, apoptosis and transportation in liver cell, which might be quite important for elucidating the regulatory network of gene expression associated with the liver damage, also important for finally discovering the pathogenic mechanisms of immunological liver damage.     

In vitro compared activity of telithromycin and azithromycin against northwest Italian isolates of Streptococcus pyogenes and Streptococcus pneumoniae with different erythromycin susceptibility

Aims: This study compared the in vitro activity of telithromycin with that of azithromycin against 438 Streptococcus pyogenes and 198 Streptococcus pneumoniae, isolated over the period 2005–2007 from specimens of different human origin obtained in three Piemonte Region’s hospitals. Methods and Results: The determination of antimicrobial activity was evaluated by the microdilution broth method and the erythromycin‐resistant (Ery‐R) phenotypes by the triple‐disc test. Exactly 78·8% of S. pyogenes and 69·2% of S. pneumoniae were erythromycin‐susceptible (Ery‐S). Concerning S. pyogenes, telithromycin was active against M and inducible MLS_B, subtype‐C, phenotypes but not against constitutive MLS_B strains. Telithromycin acted well against all S. pneumoniae, irrespective of their mechanism of macrolide‐resistance. On the contrary, the Ery‐R isolates, both S. pyogenes and S. pneumoniae, were resistant to azithromycin. Conclusions: Our results indicate that macrolide resistance in streptococci still persist in northwest Italy (21·2% of S. pyogenes and 30·8% of S. pneumoniae) and that telithromycin is confirmed as being extremely active even against recent clinical Ery‐R streptococcal isolates. Significance and Impact of the Study: The present study emphasizes that an active surveillance of the phenotype distribution and antibacterial resistance in streptococci is essential in guiding the effective use of empirical treatment option for streptococcal infections, also at regional level.     

A rhesus macaque model of Streptococcus pneumoniae carriage

Background Nasopharyngeal colonization by Streptococcus pneumoniae precedes pneumococcal disease. Elucidation of procedures to prevent or eradicate nasopharyngeal carriage in a model akin to the human would help to diminish the incidence of both pneumonia and invasive pneumococcal disease. Methods We conducted a survey of the nasopharynx of infant rhesus macaques from our breeding colony, in search of natural carriers of S. pneumoniae. We also attempted experimental induction of colonization, by nasopharyngeal instillation of a human S. pneumoniae strain (19F). Results None of 158 colony animals surveyed carried S. pneumoniae in the nasopharynx. Colonization was induced in eight of eight infant rhesus by nasopharyngeal instillation and lasted 2 weeks in 100% of the animals and 7 weeks in more than 60%. Conclusion Rhesus macaques are probably not natural carriers of S. pneumoniae. The high rate and duration of colonization obtained in our experiments indicates that the rhesus macaque will serve as a human‐like carriage model.     

Significant variation in transformation frequency in Streptococcus pneumoniae

The naturally transformable bacterium Streptococcus pneumoniae is able to take up extracellular DNA and incorporate it into its genome. Maintaining natural transformation within a species requires that the benefits of transformation outweigh its costs. Although much is known about the distribution of natural transformation among bacterial species, little is known about the degree to which transformation frequencies vary within species. Here we find that there is significant variation in transformation frequency between strains of Streptococcus pneumoniae isolated from asymptomatic carriage, and that this variation is not concordant with isolate genetic relatedness. Polymorphism in the signalling system regulating competence is also not causally related to differences in transformation frequency, although this polymorphism does influence the degree of genetic admixture experienced by bacterial strains. These data suggest that bacteria can evolve new transformation frequencies over short evolutionary timescales. This facility may permit cells to balance the potential costs and benefits of transformation by regulating transformation frequency in response to environmental conditions.     

肺炎链球菌转化模型的建立与优化

建立肺炎链球菌转化模型,优化转化体系,提高转化率,以便于进一步研究其致病的分子机制。制备肺炎链球菌感受态,首先在不同菌密度下转化外源DNA,计数抗生素筛选平板上的转化菌落,比较其转化率,确定转化的最适菌密度;然后在此菌密度下比较CSP诱导不同时相的转化率,同时用RT-PCR检测感受态调控基因comE的表达。对所用血清3型菌株而言转化的最适菌密度在OD550=0.09~0.10之间;CSP-2诱导10 min后转化率最高,可达(15.6±3)%;comE的表达也在CSP-2诱导10 min后达到最高。在实验室条件下,肺炎链球菌转化受多种因素的影响,必需控制好各种因素,选择最优条件才能获得稳定、高效的转化。     

Versatility of choline metabolism and choline-binding proteins in Streptococcus pneumoniae and commensal streptococci

The pneumococcal choline-containing teichoic acids are targeted by choline-binding proteins (CBPs), major surface components implicated in the interaction with host cells and bacterial cell physiology. CBPs also occur in closely related commensal species, Streptococcus oralis and Streptococcus mitis , and many strains of these species contain choline in their cell wall. Physiologically relevant CBPs including cell wall lytic enzymes are highly conserved between Streptococcus pneumoniae and S. mitis . In contrast, the virulence-associated CBPs, CbpA, PspA and PcpA, are S. pneumoniae specific and are thus relevant for the characteristic properties of this species.     

Discovery of novel Streptococcus pneumoniae antigens by screening a whole-genome lambda-display library

Streptococcus pneumoniae is a causative agent of otitis media, pneumonia, meningitis and sepsis in humans. For the development of effective vaccines able to prevent pneumococcal infection, characterization of bacterial antigens involved in host immune response is crucial. In order to identify pneumococcal proteins recognized by host antibody response, we created an S. pneumoniae D39 genome library, displayed on lambda bacteriophage. The screening of such a library, with sera either from infected individuals or mice immunized with the S. pneumoniae D39 strain, allowed identification of phage clones carrying S. pneumoniae B-cell epitopes. Epitope-containing fragments within the families of the histidine-triad proteins (PhtE, PhtD), the choline-binding proteins (PspA, CbpD) and zinc metalloproteinase B (ZmpB) were identified. Moreover, library screening also allowed the isolation of phage clones carrying three distinct antigenic regions of a hypothetical pneumococcal protein, encoded by the ORF spr0075 in the R6 strain genome sequence. In this work, Spr0075 is first identified as an expressed S. pneumoniae gene product, having an antigenic function during infection.     

142例儿童感染肺炎链球菌的耐药性分析

目的分析儿科病房的肺炎链球菌的主要分布情况以及耐药现状。方法收集宁波市妇女儿童医院儿科病房2010年1月1日至2012年12月31日临床分离的142株肺炎链球菌,采用法国生物梅里埃公司的VITEK-60型全自动微生物分析仪进行菌株鉴定。采用纸片扩散法（K—B法）做药敏试验,用参考菌株做质量控制。药敏试验结果按NCCL2002版判断标准,对照参考菌株判断敏感,中介和耐药。结果分离的142株肺炎链球菌的送检科室以呼吸科最多62株,其次是小儿监护病房21株,新生儿科送检标本中未培养出肺炎链球菌。分离的142株肺炎链球菌的标本以痰液标本最多103株。分离的142株肺炎链球菌对克林霉素,红霉素的耐药率分别为98．5％和95．07％且呈现逐年上升;对氨苄西林、氨苄西林舒巴坦钠、头孢呋辛、头孢曲松和万古霉素的敏感率分别为84．51％、89．44％、93．66％、97．89％和100％。结论本地区住院儿童的肺炎链球菌来源仍以呼吸道为主,对广谱半合成青霉素仍较敏感,对β-内酰胺酶抑制剂的广谱半合成青霉素敏感率更高,对头孢类敏感率更高,未发现对万古霉素耐药菌株。在门急诊可选用广谱半合成青霉素作为治疗肺炎链球菌的首选用药,在病房可选用敏感性更高的头孢呋新或头孢曲松治疗肺炎链球菌．但为了延缓耐药性的产生,应动态监测肺炎链球菌的耐药情况,合理选择抗生素,提高疗效。     

A solute binding protein of Streptococcus pneumoniae iron transport

Streptococcus pneumoniae causes considerable morbidity and mortality throughout the world. Iron acquisition is an important virulence factor for bacterial pathogens. Two loci, piu and pia, were identified as responsible for the hemoglobin utilization of S. pneumoniae. The binding activity and surface accessibility of the solute binding protein of PiuA were studied. PiuA is a lipoprotein, binds hemin and hemoglobin, resides on the cytoplasmic membrane, and is not exposed on the surface of S. pneumoniae. The localization of PiuA has implications in its role in hemoglobin utilization and possible use as a pneumococcal vaccine.     

Isolation,identification of Streptococcus pneumoniae from infected rhesus monkeys and control efficacy

Background Streptococcus pneumoniae can cause a wide variety of illnesses. Primate animals can be infected by the pneumococcus. A disease occurred among rhesus monkeys in winter 2006. Methods Routine clinical observation, necropsies, bacteriological examinations were conducted, and PCR, pathogenicity to BALB/c mice and antibiotic susceptibility test were examined additionally. Results We conclude that the agent is S. pneumoniae. Based on the antibiotic susceptibility test, a dose of 20 mg/kg body weight daily of Erythromycin was given intramuscular injection for 5 days, resulting in the disappearance of clinical signs, and no newly case reappear be observed till today. Conclusions Therefore, it is suggested that the outbreak of respiratory disease in the rhesus monkeys was because of transmission of S. pneumoniae among rhesus monkeys. The antibiotic therapy finding underscores the utility of Erythromycin to cure the infected rhesus monkeys without causing side effects and without contributing to the further development of antibiotic resistance.     

Experimental infection of rhesus macaques with Streptococcus pneumoniae: a possible model for vaccine assessment

BACKGROUND: We explored the possibility of using normal adult rhesus macaques for the preclinical assessment of safety, immunogenicity, and efficacy of newly developed vaccines against Streptococcus pneumoniae infection of the lung. METHODS: Our primary objective was to determine whether an intra-bronchial inoculum of at least 10(6)S. pneumoniae colony-forming units, or one as high as 10(8)-10(9) organisms, could detectably survive in rhesus macaques for a period longer than 1-2 weeks. If so, we hypothesized, it would be possible to observe signs of pneumonia commonly observed in humans, and discriminate between vaccinated/protected animals and controls. Infection was detectable in bronchoalveolar lavage fluids 3-5 weeks post-inoculation. RESULTS: The clinical course of disease mimicked aspects of that of human pneumococcal pneumonia. Signs of inflammation typical of the disease in humans, such as elevated concentrations of neutrophils and of pro-inflammatory cytokines in bronchoalveolar lavage fluids were also observed. CONCLUSIONS: These findings underscore the utility of this model to assess the safety, immunogenicity, and efficacy of newly developed S. pneumoniae vaccines.     

肺炎链球菌致病机理的最新研究进展

肺炎链球菌致病过程包括粘附 ,炎症反应 ,细菌产物的细胞毒作用。阻止肺炎链球菌粘附到宿主细胞受体和定植在粘膜表面 ,是预防其感染的最有效的途径。综述了肺炎链球菌粘附过程的最新研究进展和肺炎链球菌毒力因子及其可能的致病机理 ,对研制新一代疫苗 ,预防和治疗肺炎链球菌感染有重要意义。     

114株肺炎链球菌的临床分布及药敏分析

目的波市妇女儿童医院肺炎链球菌的临床分布和耐药情况,为临床合理用药提供依据。方法对该院2009年6月1日至2011年3月31日期间分离的114株肺炎链球菌进行分析,菌株鉴定采用法国生物梅里埃公司的VITEK60分析仪,药敏试验采用K-B法,用参考菌株做质量控制。结果该院分离的肺炎链球菌主要来自儿童（84.21%）,标本来源主要是痰液（61.4%）,其次是血液（9.65%）,其他（28.95%）。肺炎链球菌的耐药率：林可霉素92.19%,红霉素90.12%,青霉素G85.53%,左旋氧氟沙星20.24%,氨苄西林16.67%,头孢唑啉8.7%,头孢曲松5.8%,头孢噻肟4.11%,万古霉素0%,氨苄西林/舒巴坦0%,哌拉西林/他唑巴坦0%。结论宁波市妇女儿童医院肺炎链球菌对某些药物的耐药率很高,有必要对其进行耐药率监测,指导临床合理选择抗菌药物。     

侵袭性和非侵袭性肺炎链球菌耐药率的比较分析

目的研究侵袭性和非侵袭性肺炎链球菌的耐药谱的差异,指导合理应用抗生素及感染管理。方法回顾性统计分析2009至2011年来天台县人民医院就诊患者分离肺炎链球菌的标本来源及耐药性,比较侵袭性和非侵袭性肺炎链球菌耐药率之间的差异。结果共分离出肺炎链球菌642株,痰液中分离出584株,非痰液中分离出58株,其中血液中分离出32株,脑脊液中分离出20株,其他分离出6株,所有肺炎链球菌对万古霉素和利奈唑胺均敏感,对青霉素、红霉素、克林霉素、四环素及复方新诺明耐药严重,对左氧氟沙星、氯霉素比较敏感;侵袭性分离株对青霉素、红霉素、克林霉素、左氧氟沙星、四环素及氯霉素的耐药率显著高于非侵袭性肺炎链球菌。结论该院分离的肺炎链球菌主要来自痰液标本,耐青霉素肺炎链球菌的检出率高,大环内酯类耐药严重,存在一定比例的侵袭性感染,非侵袭菌株与侵袭性菌株耐药谱之间存在一定差异,临床治疗应该区别对待,系统的监测细菌耐药性,合理选择抗菌药物。     

Activity of Nidus Vespae extract and chemical fractions against Streptococcus mutans biofilms

AIMS: To evaluate the effect of Nidus Vespae extract and chemical fractions on the viability and architecture of Streptococcus mutans biofilms. METHODS AND RESULTS: The raw material was first extracted using 95% ethanol/water. Subsequent fractions were prepared from this extract using cyclohexane/ethyl acetate, petroleum ether/ethyl acetate and chloroform/methanol. The biomass dry weight and total protein of samples treated with Nidus Vespae extract and chemical fractions were significantly less than those treated with the vehicle control (P < 0.05). Biofilms treated with Nidus Vespae also resulted in lower percentage of polysaccharide composition. The pH decrease in the biofilm matrix was retarded by Nidus Vespae compared with the vehicle control. Architecture of biofilms treated with Nidus Vespae was different than in the vehicle control and 0.05% chlorhexidine. CONCLUSIONS: Chloroform/methanol fraction was the most effective treatment. SIGNIFICANCE AND IMPACT OF THE STUDY: The significant antibiofilm activity demonstrated by Nidus Vespae shows it to be a promising source of novel anticariogenic agents.