变形链球菌在日托儿童口腔中水平传播的初探

目的 通过对日托儿童口腔中变形链球菌（S.mutans）水平传播的研究，为儿童龋的早期预防提供新思路。方法 选择32名3～4岁日托儿童，根据是否患龋分为有龋组和无龋组。用无菌牙签采集牙面菌斑，MSB琼脂培养，微量生化反应鉴定分离S.mutans菌落，纯培养后提取基因组DNA，用AP-PCR检测其基因多态性，对来自不同个体的具有相似AP-PCR扩增图谱的菌株再进行DNA指纹分析。结果 32名受检儿童中，变形链球菌的检出率为78.1%；有龋组和无龋组的变形链球菌检出率分别为100%和69.6%。在检出变形链球菌的25名儿童中，携带有2种及以上基因型的儿童占88%；有龋组为88.9%，无龋组为87.5%，OR值为1.143，二者之间的差异无统计学意义。DNA指纹分析表明，有2种基因型变形链球菌分别在2名儿童口腔中重复检出。结论 变形链球菌在日托儿童中可能存在水平传播，但其基因型检出数目与龋的发生关系不明显。     

新生期肺炎链球菌肺炎对气道平滑肌表型的影响

目的研究新生期肺炎链球菌肺炎(Streptococcus pneumoniae pneumonia,S.pp)对气道平滑肌表型的影响。方法Balb/c小鼠出生后第7天鼻腔滴注2×107CFU肺炎链球菌5μl建立新生期S.pp模型,对照组滴注等量PBS。感染5周后收集肺组织标本,免疫组织化学检测气道平滑肌肌层厚度;RT-PCR检测气道平滑肌Acta2-mRNA、My11-mRNA、Tagln-mRNA表达量;Western blot检测α-SMA、SMMHC、SM22α蛋白表达量。结果 S.pp组气道平滑肌面积(α-SMA+area/Pbm)较对照组显著增加(46.06±10.74 vs 22.50±9.131,P<0.01),平滑肌收缩蛋白SMMHC面积(SMMHC+area/Pbm)较对照组明显增加(58.33±29.40 vs19.75±13.10,P<0.05),2组间平滑肌收缩蛋白SM22α面积(SM22α+area/Pbm)无统计学差异(37.20±10.67 vs 41.33±5.871,P>0.05);Western blot分析发现S.pp组小鼠肺组织α-SMA、SMMHC蛋白较对照组显著升高(分别为1.352±0.552 9 vs 0.633 0±0.157 5,P<0.05;1.291±0.487 2 vs 0.776 8±0.279 3,P<0.01),肺组织SM22α蛋白表达水平差异无统计学意义(1.435±0.436 5 vs 1.398±0.437 3,P>0.05);RT-PCR检测发现S.pp组Acta2-mRNA、My11-mRNA表达水平较对照组显著增加(分别为2.704±1.044 vs0.906 5±0.214 8,P<0.01;1.780±0.454 6 vs 1.183±0.369 9,P<0.05),而2组间Tagln-mRNA表达水平无统计学差异(1.438±0.321 3vs 1.207±0.334 5,P>0.05)。结论新生期肺炎链球菌肺炎可诱导气道平滑肌表型改变,促进气道高反应性形成。     

A Novel PspA Protein Vaccine Intranasal Delivered by Bacterium-Like Particles Provides Broad Protection Against Pneumococcal Pneumonia in Mice

Background: Streptococcus pneumoniae is a major pathogen accounting for a large number of pneumococcal disease in worldwide. Due to the mucosal immune pathway induces both systemic and mucosal immune responses, the potential strategy to prevent pneumococcal disease may be to develop a mucosal vaccine.

Method: In this study, we developed an intranasal pneumococcal protein vaccine based on a bacterium-like particle (BLP) delivery system. PspA is expressed and exposed on the surface of all pneumococcal strains, which confers the potential to induce immune responses to protect against pneumococcal infection. We fused one of the pneumococcal surface proteins (PspA, family2 clade4) with the protein anchor (PA) protein in order to display PspA on the surface of BLPs.

Result: The current results showed that intranasal immunization with BLPs/PspA-PA efficiently induced both PspA-specific IgG in the serum and PspA-specific IgA in mucosal washes. And intranasal immunization of BLPs/PspA-PA could provide complete protection in a mouse challenge model with pneumococci of different two clades of both homologous and heterologous PspA families.

Discussion and conclusion: Thus, targeted delivery of multiple bacterial antigens via BLPs may prevent pneumococcal disease by inducing both systemic and mucosal immune responses.     

肺炎链球菌细胞壁表面粘附相关蛋白的初步鉴定

通过Ｗｅｓｔｅｒｎｂｌｏｔ将肺炎链球菌细胞壁表面蛋白质转移到ＰＶＤＦ膜上，然后与生物素标记的巨噬细胞在膜上进行粘附实验，初步鉴定出六条细胞壁表面粘附相关蛋白，它们的分子量分别是２０，３０，３７，５９，６６，８５ｋＤ其生物学特性，功能有待进一步研究确定，这为进一步研究肺炎链球菌致病机理，发展新一代多价疫苗和开发抗菌药物奠定了一定的基础。     

不同地区A组乙型溶血性链球菌T分型与耐药关系

目的　探讨我国 4个省市自然人群中学龄儿童A组乙型溶血性链球菌 (groupAofStreptococcus,GAS)T分型与耐药关系。方法　T凝集法将GAS进行T分型 ,再用Vitek微生物鉴定系统进行药敏试验。测试江陵 5 7株、丰满 95株、重庆 71株、广州 397株GAS。结果　不同T型的GAS对红霉素、氯林可霉素、四环素的耐药性有显著差异 (P <0 .0 5 ) ,对红霉素耐药率高的菌型依序为T4、T1、T11、T6、T12 ;对氯林可霉素耐药率高的菌型为T1、T12、T6 ;对四环素耐药率高的菌型为T11、T3/B、T12、T4、T1。除广州农村外 ,各地的优势菌型为T1型 ,但不同地区T1型GAS的耐药率有差异 (P <0 .0 1)。结论　 4个省市自然人群儿童中携带的GAS对红霉素、氯林可霉素、四环素耐药率与T型有关 ,不同T型的GAS耐药率不同 ;同一T型GAS的耐药性有地区差异     

Antibiotic Susceptibility of Periodontal Streptococcus constellatus and Streptococcus intermedius Clinical Isolates

Background: Streptococcus constellatus and Streptococcus intermedius in subgingival dental plaque biofilms may contribute to forms of periodontitis that resist treatment with conventional mechanical root debridement/surgical procedures and may additionally participate in some extraoral infections. Because systemic antibiotics are often used in these clinical situations, and little is known of the antibiotic susceptibility of subgingival isolates of these two bacterial species, this study determined the in vitro susceptibility to six antibiotics of fresh S. constellatus and S. intermedius clinical isolates from human periodontitis lesions. Methods: A total of 33 S. constellatus and 17 S. intermedius subgingival strains, each recovered from separate patients with severe chronic periodontitis (n = 50) before treatment, were subjected to antibiotic gradient strip susceptibility testing with amoxicillin, azithromycin, clindamycin, ciprofloxacin, and doxycycline on blood‐supplemented Mueller‐Hinton agar and to the inhibitory effects of metronidazole at 16 mg/L in an enriched Brucella blood agar dilution assay. Clinical and Laboratory Standards Institute and European Committee on Antimicrobial Susceptibility Testing interpretative standards were used to assess the results. Results: Clindamycin was the most active antibiotic against S. constellatus (minimum inhibitory concentration at 90% [MIC₉₀] 0.25 mg/L), and amoxicillin was most active against S. intermedius (MIC₉₀ 0.125 mg/L). A total of 30% of the S. constellatus and S. intermedius clinical isolates were resistant in vitro to doxycycline, 98% were only intermediate in susceptibility to ciprofloxacin, and 90% were resistant to metronidazole at 16 mg/L. Conclusion: Subgingival S. constellatus and S. intermedius exhibited variable antibiotic susceptibility profiles, potentially complicating empirical selection of periodontitis antibiotic therapy in patients who are species positive.     

Evaluation of Streptococcus mutans adhesion to fluoride varnishes and subsequent change in biofilm accumulation and acidogenicity

Objectives

The aim of this study was to evaluate Streptococcus mutans adhesion to fluoride varnishes and subsequent change in biofilm accumulation and acidogenicity.

Methods

After producing fluoride varnish-coated hydroxyapatite discs using Fluor Protector (FP), Bifluorid 12 (BIF), Cavity Shield (CASH), or Flor-Opal Varnish White (FO), S. mutans biofilms were formed on the discs. To assess S. mutans adhesion to the discs, 4-h-old biofilms were analysed. To investigate the change in biofilm accumulation during subsequent biofilm formation, the biomass, colony forming units (CFU), and water-insoluble extracellular polysaccharides (EP) of 46-, 70-, and 94-h-old biofilms were analysed. To investigate the change in acidogenicity, pH values of the culture medium were determined during the experimental period. The amount of fluoride in the culture medium was also determined during the experimental period.

Results

BIF, CASH, and FO affected S. mutans adhesion (67–98% reduction) and subsequent biofilm accumulation in 46-, 70-, and 94-h-old biofilms. However, the reducing effect of the fluoride varnishes on the biomass, CFU count, water-insoluble EP amount, and acid production rate of the biofilms decreased as the biofilm age increased. These results may be related to the fluoride-release pattern of the fluoride varnishes. Of the fluoride varnishes tested, FO showed the highest reducing effect against the bacterial adhesion and subsequent biofilm accumulation.

Conclusions

Our findings suggest that if the results of these experiments are extrapolable to the in vivo situation, then reduced clinical benefit of using fluoride varnishes may occur with time.

Clinical significance

Fluoride varnish application can affect cariogenic biofilm formation but the anti-biofilm activity may be reduced with time.     

含碘的乳过氧化物酶-过氧化氢-硫氰化物系统对变异链球菌致龋性的影响

目的 研究含不同浓度碘（I-）的乳过氧化物酶-过氧化氢-硫氰化物系统（LPO-H2O2-SCN-）对变异链球菌生长、黏附、产水不溶性细胞外多糖以及葡萄糖基转移酶（GTF）活性的影响。方法 选用 S.mutans ATCC 25175为实验菌株。采用菌落形成单位（CFU）计数法进行生长实验;用分光光度计法测定细菌的黏附抑制率;用蒽酮法测定水不溶性细胞外多糖的质量浓度;用蒽酮法测定还原糖量,计算 GTF活性。结果 随着 I-浓度的增高,含I-的 LPO-H2O2-SCN-抗菌系统对 S.mutans致龋力的抑制作用增强。当I-≥100 μmol•L-1时,对 S.mutans的生长抑制明显高于对照组（ P<0.05）;且当I-≥1 000 μmol•L-1时,对S.mutans的生长抑制显著高于以硫氰酸盐（SCN-）为单底物的实验组（P<0.05）;当I-≥100 μmol•L-1时,对S.mutans的黏附抑制率达到50%以上,水不溶性细胞外多糖生成量明显减少（ P<0.05）, GTF活性也明显降低（P<0.05）。结论 通过增加 I-的浓度,可以抵消生理浓度的 SCN-的抑制作用,使含I-的LPO-H2O2-SCN-系统能显著抑制变异链球菌的生长、黏附、水不溶性细胞外多糖生成和GTF活性。     

Molecular pathogenicity of Streptococcus anginosus

Streptococcus anginosus and the closely related species Streptococcus constellatus and Streptococcus intermedius, are primarily commensals of the mucosa. The true pathogenic potential of this group has been under‐recognized for a long time because of difficulties in correct species identification as well as the commensal nature of these species. In recent years, streptococci of the S. anginosus group have been increasingly found as relevant microbial pathogens in abscesses and blood cultures and they play a pathogenic role in cystic fibrosis. Several international studies have shown a surprisingly high frequency of infections caused by the S. anginosus group. Recent studies and a genome‐wide comparative analysis suggested the presence of multiple putative virulence factors that are well‐known from other streptococcal species. However, very little is known about the molecular basis of pathogenicity in these bacteria. This review summarizes our current knowledge of pathogenicity factors and their regulation in S. anginosus.