无症状菌尿与孕晚期阴道B族链球菌定植的关联性分析

目的 分析无症状菌尿(ASB)与孕晚期阴道B族链球菌定植的相关性。方法 以2018年1月至2021年6月建卡随访的4287名孕妇为研究对象,其中伴ASB孕妇为观察组,按1∶4进行匹配不伴ASB孕妇作为对照组,分析ASB与孕晚期阴道B族链球菌定植的相关性。结果 4287名孕妇中,伴ASB孕妇158名,ASB发生率为3.69%,孕晚期B族链球菌定植28例,定植率17.72%;不伴ASB孕妇632名,孕晚期B族链球菌定植44例,定植率6.96%。伴ASB组孕妇孕晚期B族链球菌定植率大于不伴ASB组,差异有统计学意义(χ²=17.666,P<0.001)。Logistic分析结果显示,ASB与孕晚期阴道B族链球菌定植呈正相关(OR=2.577,95%CI=1.509~4.402,P=0.001)。结论 ASB与孕晚期阴道B族链球菌定植呈正相关,早期ASB的筛查与防控对降低孕晚期阴道B族链球菌定植率有重要意义。     

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.     

Streptococcus gallolyticus subsp. pasteurianus meningitis in an infant

Streptococcus gallolyticus subsp. pasteurianus was formerly classified as S. bovis biotype II/2, which is recognized as a rare cause of neonatal sepsis and meningitis. Since the taxonomy classification change, there have not been many reports of meningitis due to S. gallolyticus subsp. pasteurianus. Moreover, the pathogenesis of late onset S. gallolyticus subsp. pasteurianus meningitis in infants is unclear. Here we report a case of meningitis in a 5‐week‐old infant with preceding diarrhea. S. bovis biotype II/2 was isolated from the blood, cerebrospinal fluid and stool, and then was identified as S. gallolyticus subsp. pasteurianus on 16S rRNA gene sequencing. Isolates from all three sample types had identical profiles on pulsed‐field gel electrophoresis. The intestinal tract was thought to be the source of the infection.     

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.     

泌尿生殖道分离无乳链球菌药物敏感性分析

目的了解泌尿生殖道无乳链球菌感染及耐药状况,为临床用药提供依据。方法对临床送检的泌尿生殖道标本常规培养鉴定,并对分离出的无乳链球菌进行纸片扩散法药敏试验,对红霉素耐药、克林霉素敏感的菌株做D试验检测。结果144株无乳链球菌(尿77株,前列腺液36株,阴道分泌物31株)药敏结果显示,对万古霉素、利奈唑胺、青霉素和头孢曲松的耐药率最低,全部144株无乳链球菌中未发现耐药株;左氧氟沙星的耐药率较低,为16.2%;红霉素和克林霉素耐药率较高,分别为56.2%和53.5%。D试验阳性率为26.7%。结论从泌尿生殖道分离的无乳链球菌对青霉素、氨苄西林和头孢菌素类抗菌药物的敏感性较高,但对大环内酯类和克林霉素已有一定的耐药。     

Pathogens resistant to antibacterial agents

Resistance to antimicrobial drugs is increasing at an alarming rate among both gram-positive and gram-negative bacteria. Traditionally, bacteria resistant to multiple antimicrobial agents have been restricted to the nosocomial environment. A disturbing trend has been the recent emergence and spread of resistant pathogens in nursing homes, in the community, and in the hospital. This article reviews the epidemiology, molecular mechanisms of resistance, and treatment options for pathogens resistant to antimicrobial drugs.     

肺炎支原体肺炎患儿口咽部常见细菌及临床意义北大核心CSCD

目的:了解肺炎支原体肺炎(MPP)患儿口咽部常见细菌及临床意义。方法:回顾性分析。选取中国医科大学附属盛京医院小儿呼吸内科2016年12月至2017年6月住院治疗的134例MPP患儿为研究对象,选取同期同医院42例健康儿童为健康对照组。采用荧光定量聚合酶链反应Taqman探针法检测入组儿童口咽部常见细菌[肺炎链球菌(SP)、卡他莫拉杆菌(CTA)、流感嗜血杆菌(HI)]。首先比较MPP患儿及健康儿童口咽部细菌检出情况,再将134例MPP患儿根据年龄(<1岁、1~<3岁、3~<6岁及6~14岁)、有无细菌检出[肺炎支原体(MP)、MP+细菌]及检出菌种不同(MP+SP、MP+CTA及MP+HI)进行分组比较。采用秩和检验及 χ^(2)检验对相关临床资料进行分析。 结果:134例MPP患儿检出细菌79例(58.96%),42例健康儿童检出细菌17例(40.48%),差异有统计学意义( χ^(2)=4.404, P<0.05)。与MP组相比,MP+细菌组外周血中白细胞(WBC)水平[8.5(6.7,12.0)×10^(9)/L比7.8(5.8,9.3)×10^(9)/L, Z=-2.232]、C反应蛋白(CRP)水平[19.2(7.2,35.0) mg/L比8.4(3.4,24.6) mg/L, Z=-2.810]、乳酸脱氢酶(LDH)水平[286(244,365) U/L比250(210,302) U/L, Z=-2.474]及大叶性肺炎比例[40.51%(32/79例)比18.18%(10/55例), χ^(2)=7.510]、胸腔积液比例[13.92%(11/79例)比3.64%(2/55例), χ^(2)=3.917]、难治性肺炎支原体肺炎(RMPP)比例[34.18%(27/79例)比18.18%(10/55例), χ^(2)=4.151]均较高;总热程[10(7,12) d比8(6,10) d, Z=-2.706]及抗生素使用时间[16(13,19) d比12(9,16) d, Z=-3.747]均较长,差异均有统计学意义(均 P<0.05)。MP+SP组外周血中WBC高于MP+HI组[12.20(7.80,17.30)×10^(9)/L比6.75(5.37,9.44)×10^(9)/L],差异有统计学意义( Z=11.574, P<0.05);MP+SP组[56.67%(17/30例)]大叶性肺炎发生率高于MP+CTA组[0(0/3例)]和MP+HI组[18.75%(3/16例)],差异有统计学意义( χ^(2)=9.770, P<0.05)。 结论:MPP患儿口咽部更易发生细菌定植或感染,当WBC、CRP及LDH均明显升高,影像表现为大片实变影或有胸腔积液时,提示可能混合细菌感染,热程更长,难治性MPP比例增高,且常见的混合细菌为SP。     

肺炎链球菌不同菌株自溶酶基因的克隆、序列分析及重组表达

目的克隆肺炎链球菌自溶酶(LytA)的基因序列，并进行重组表达。方法分别提取不同临床分离株的基因组DNA，根据已知肺炎链球菌野生R6株LytA基因序列设计引物，进行PCR扩增，将获得的目的基因片段克隆人原核表达质粒，然后测序；利用生物信息学方法，对不同临床分离株LytA基因序列进行比较分析，同时进行LytA基因的重组表达。结果从不同临床分离株的基因组中均扩增出完整的LytA基因片段，成功构建了重组质粒pGEX-4T-1-LytA。比较不同临床分离株LytA基因的DNA序列及推测的氨基酸序列，发现各株LytA基因序列及氨基酸序列间存在差异。通过异丙基巯基半乳糖(IPTG)诱导，LytA基因在大肠埃希菌JM109中得到高效表达，十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE)结果显示pGEX-4T-1-LytA融合蛋白相对分子质量约62000，与理论预测一致。结论序列分析发现各分离株的LytA基因序列及氨基酸序列间存在差异，但同源性极高，推测LytA基因序列保守，可用于疫苗研发。