常见革兰阳性链球菌的生化表型及药敏分析

目的了解革兰阳性链球菌生化表型及药敏情况。方法采用VITEK细菌自动分析仪及手工生化、药敏相结合的方法鉴定链球菌。结果革兰阳性链球菌生化表型菌名29种,生化反应共性12种,具有诊断特性的生化反应表型三种,杆菌肽不能作为A群链球菌的确诊试验,A群链球菌、肺炎链球菌对青霉素、万古霉素的耐药率0%,肺炎链球菌对阿奇霉素、克林霉素的耐药率超过了60%。三代头孢和三代头孢加酶抑制剂的药物,耐药率低,可以作为治疗链球菌感染的首选药物之一。结论革兰阳性链球菌生化表型的建立,可以解决细菌鉴定中出现"不能鉴定"的问题,给细菌鉴定提供一定的帮助;了解细菌耐药情况,为临床医生合理用药提供理论依据。     

社区肺炎链球菌感染药敏分析及分子生物学分型

目的调查该院肺炎链球菌药敏谱及耐药基因型,为肺炎链球菌感染的预防与治疗提供参考。方法收集该院2014年1月至2016年12月分离的肺炎链球菌共184株,用Vitek 2鉴定菌株,检测耐药模式,PCR方法检测耐药基因erm(B)、mef(A)。结果肺炎链球菌对青霉素G的耐药率为60.6%,对红霉素、克林霉素的耐药率分别为93.3%、100.0%。耐药表型为MLSB型的检出率为93.5%(cMLSB:89.7%,iMLSB:3.8%),未检出M耐药表型。耐药基因erm(B)的检出率为91.3%,mef(A)的检出率为1.6%。结论该院肺炎链球菌对红霉素与克林霉素的耐药率较高;耐药表型以erm(B)编码的cMLSB耐药表型为主,主要以靶位点的修饰为主,也与泵外排机制有关。     

龋病患儿唾液中sIgA、MMPs、变形链球菌、远缘链球菌变化与病情程度的相关性

目的 探讨龋病患儿唾液中分泌型免疫球蛋白A(sIgA)、基质金属蛋白酶(MMPs)的变化与唾液中变形链球菌、远缘链球菌检出水平的相关性。方法 回顾性选取2019年7月至2021年7月自贡市第一人民医院口腔门诊确诊的重度龋病患儿60例(重度组)、轻度龋病患儿60例(轻度组)、无龋病患儿60例(对照组)。采用酶联免疫吸附试验检测3组患儿唾液中sIgA、MMPs水平,采用实时单量PCR技术检测3组儿童唾液中变形链球菌、远缘链球菌水平,并分析sIgA、MMPs与变形链球菌、远缘链球菌的相关性。结果 重度组患儿唾液中sIgA、MMP-2、MMP-9水平均分别高于对照组,轻度组sIgA、MMP-9水平分别高于对照组,重度组患儿唾液中sIgA、MMP-2水平均分别高于轻度组,差异均有统计学意义(P<0.05)。重度组患儿唾液中变形链球菌、远缘链球菌水平均分别高于轻度组、对照组,轻度组唾液中变形链球菌、远缘链球菌水平分别高于对照组,差异均有统计学意义(P<0.05)。经线性相关法分析,龋病患儿唾液中变形链球菌、远缘链球菌、sIgA、MMP-2、MMP-9水平与龋失补指数均呈正相关关系(r=...     

miR-23b-3p靶向PALM3对肺炎链球菌诱导的肺泡上皮细胞凋亡及炎症因子表达的影响

目的研究miR-23b-3p对肺炎链球菌诱导的肺泡上皮细胞凋亡和炎症的作用及机制。方法将肺泡上皮细胞A549细胞分为对照组、感染组、转染组、感染组+转染组;对照组A549细胞常规培养,感染组用1×108 CFU/mL肺炎链球菌培养A549细胞,转染组转染不同载体,感染组+转染组在A549细胞被肺炎链球菌处理前48h进行转染。qRT-PCR检测细胞中miR-23b-3p和paralemmin-3(PALM3)mRNA的水平,流式细胞术检测细胞凋亡率,Western blot检测细胞中PALM3、B淋巴细胞瘤-2基因(Bcl-2)和Bcl-2相关X蛋白(Bax),酶联免疫法(ELISA)检测肺炎链球菌诱导后细胞培养上清中白介素-6(interleukin 6,IL-6)和白介素-10(interleukin 10,IL-10)的含量;双荧光素酶报告系统验证miR-23b-3p与PALM3的关系。结果与对照组相比,感染组A549细胞中miR-23b-3p、IL-10、Bcl-2含量明显降低(P0.05),PALM3、IL-6、Bax水平及细胞凋亡率明显升高(P0.05);过表达miR-23b-3p和干扰PALM3表达均可抑制肺炎链球菌诱导的A549细胞凋亡和炎症;miR-23b-3p靶向负调控PALM3的表达;过表达PALM3逆转了过表达miR-23b-3p对肺炎链球菌诱导的A549细胞凋亡和炎症的作用。结论 miR-23b-3p靶向PALM3抑制肺炎链球菌诱导的A549炎症和细胞凋亡。     

风湿热的病因探讨

风湿热的病因迄今尚未完全明了,科学家们从临床、流行病学、细菌学和免疫学等各方面进行了综合性研究,将其病因大致分两方面: 1.A组溶血性链球菌与风湿热的发病关系:A组溶血性链球菌感染与风湿热的发病有密切的关系,它表现在以下几个方面:第一,风湿热的流行季节及分布地区常常与溶血性链球菌疾病(如急性扁桃体炎、猩红热等)的流行及分布相一致。在我国北方气候寒冷的地区,溶血性链球菌感染的发病率高,风湿热的发病也较高;第二,在风湿热的患者中,有相当一部分人在发病之前2～3周有过链球菌感染的病史;     

A族链球菌制剂与平阳霉素分别联合激素治疗体表脉管畸形的效果对比观察

目的对比观察A族链球菌制剂与平阳霉素分别联合激素治疗体表脉管畸形的有效性与安全性。方法将我院2016年1月～2017年12月收治的100例体表脉管畸形患者为研究对象,以随机数字法分为A族链球菌制剂组(50例)和平阳霉素组(50例),A族链球菌制剂组予以A族链球菌制剂+强的松龙治疗,平阳霉素组予以平阳霉素+强的松龙治疗,两组均治疗4个月。比较两组的临床疗效及不良反应,随访6个月,比较两组的并发症及复发情况。结果 A族链球菌制剂组淋巴管畸形的治疗总有效率显著高于平阳霉素组(P0.05),两组的静脉畸形治疗总有效率比较,差异无显著性(P0.05);两组在局部肿胀、胃肠反应方面比较差异无显著性(P0.05),A族链球菌制剂组的发热反应发生率显著高于平阳霉素组(P0.05);两组复发率比较,差异无显著性(P0.05)。结论 A族链球菌制剂与平阳霉素治疗体表脉管畸形均效果肯定,且A族链球菌制剂治疗淋巴管畸形疗效更佳。     

抗DNA酶B在小儿A型溶血性链球菌感染中的诊断意义

目的探讨抗脱氧核糖核酸酶B(抗DNA酶B)在小儿A型溶血性链球菌感染所致疾病中的诊断价值.方法用抗DNA酶B微量法,测定126例A型溶血性链球菌感染所致疾病的小儿血清抗DNA酶B抗体,同时检测抗链球菌溶血素O(ASO),对两种检测方法的阳性率进行比较.结果肾炎皮损组、咽炎痊愈及肾炎恢复组抗DNA酶B阳性率100%.0及63.3%,显示高于ASO阳性率20.0%及23.3%,两者联合检测阳性率均在70.0%以上;不典型风湿热组,肾炎上感组及咽炎组抗DNA酶B阳性率分别为100.0%、87.5%和62.0%,虽和ASO(80.0%、50.0%和72.0%)无显著性差异(P＞0.05),但两者联合检测阳性率可达100%及84.0%,提示抗DNA酶B对急性肾小球肾炎诊断有重要的临床价值.结论 ASO联合抗DNA酶B检测可提高A型溶血性链球菌感染的检出率.     

自噬体在肺炎链球菌感染过程中的保护作用机制探讨

目的:检测微管相关蛋白轻链-3(LC3)在肺泡Ⅱ型上皮细胞A549上的表达情况,及3-甲基腺嘌呤(3MA)刺激后对其表达的影响,为研究自噬体在抵抗肺炎链球菌感染过程中的保护作用奠定基础.方法:体外培养肺泡Ⅱ型上皮细胞A549,在肺炎链球菌感染A549细胞12h时用倒置显微镜拍照并提取RNA,采用RT-PCR的方法检测LC3 mRNA的表达情况.同时检测对照组、3MA组、Spn组和3MA+ Spn组上清液乳酸脱氢酶(LDH)的OD值.结果:RT-PCR检测LC3 mRNA有明显表达,3MA可以抑制LC3的表达.LDH检测显示Spn组和3MA+ Spn组上清液LDH的OD值数据两两比较差异有统计学意义(P＜0.05).结论:LC3在肺泡Ⅱ型上皮细胞中显著表达,3MA可以抑制细胞的自噬作用.加3MA后,肺炎链球菌感染肺泡Ⅱ型上皮细胞坏死增加,提示自噬体在抵抗肺炎链球菌的感染过程中起一定的保护作用.     

风湿性关节炎是怎么得的?

风湿性关节炎在我国多发生于冬春阴雨季节。潮湿和寒冷是重要的诱发因素。现已公认A组溶血性链球菌感染与风湿性关节炎的发病有关。曾有学者认为,该病的发生必须具备以下四个条件:①A组溶血性链球菌感染;②人体对链球菌产生抗体反应;③A组溶血     

抗DNA酶B和抗链球菌溶血素"O"同时测定的临床价值

抗DNA酶B(Anti-DNase B)是A组溶血性链球菌产生的一种细胞外产物,刺激人体可产生抗DNA酶B(ADNs);链球菌溶血素"O"是A组溶血性链球菌的重要代谢产物,可刺激人体产生抗链球菌溶血素"O"(ASO).     

Progress in M-protein-based subunit vaccines to prevent rheumatic fever and rheumatic heart disease

Infection with the human bacterial pathogen group A Streptococcus (GAS) is estimated to cause over 500,000 deaths per year, the majority of which are related to rheumatic fever (RF) and rheumatic heart disease (RHD). While GAS is an important cause of morbidity and mortality globally, the burden of GAS-associated diseases is greater in less developed countries and in indigenous populations of developed countries. The antiphagocytic bacterial surface M protein is a major candidate antigen in the development of a vaccine to prevent GAS infection and RF/RHD. A major obstacle, however, in the development of an M-protein-based vaccine is the widespread diversity of circulating GAS strains and M protein types. Added to this is the possibility of inducing autoimmunity following vaccination as a result of molecular mimicry between the M protein and host tissue proteins. Research has been aimed at the development of a safe GAS vaccine that is able to induce broad-coverage protective immunity. The development of subunit vaccine approaches targeting the M protein using various vaccine delivery technologies is the focus of this review.     

T serotyping of group a streptococcus isolated from patients with pharyngitis or streptococcal toxic shock syndrome in Japan between 2005 and 2017

Streptococcus pyogenes (group A streptococcus; GAS) is an important gram-positive human pathogen capable of causing diseases ranging from mild superficial skin and pharyngeal infections to more severe invasive diseases, including streptococcal toxic shock syndrome (STSS). GAS produces a T protein, and T serotyping has considerable discriminatory power for epidemiological characterization of GAS. To clarify the relationship between STSS and pharyngitis in Japan, we examined the T serotypes of GAS strains isolated from clinical specimens of streptococcal infections (STSS, 951 isolates; pharyngitis, 16268 isolates) from 2005 to 2017. The most prevalent T serotype from pharyngitis isolates was T12, followed by T1, T4, and TB3264. The most prevalent T serotype from STSS isolates was T1, followed by TB3264. Trend of increase and decrease in the frequency of T1 or TB3264 isolation from pharyngitis was correlated with that of STSS patients. The increase of T1 or TB3264 strain-infection in pharyngitis patients may increase the probability of causing STSS, indicating that careful monitoring of GAS serotypes is essential for the prediction of rapid increase of STSS in time to develop effective management strategies.     

Streptococcal toxic shock syndrome following group A streptococcal vulvovaginitis in a breastfeeding woman

Streptococcal toxic shock syndrome (STSS) is a systemic, life-threatening illness usually caused by invasive respiratory tract or skin and soft tissue infections of Streptococcus pyogenes (group A streptococcus, GAS). We report the case of an adult woman with lactational amenorrhea and GAS vulvovaginitis progressing to STSS. She was admitted to our hospital because of fever, lethargy, and a 2-week history of vaginal discharge; she also had hypotension and multiple organ failure. Blood and urine cultures yielded gram-positive cocci and GAS. After 14 days of antimicrobial therapy, she fully recovered without any complications. The vulvovaginitis was most likely the portal of entry for GAS, which is rarely recognized as a causative pathogen of vulvovaginitis. Lactational amenorrhea is thought to be a risk factor for GAS vulvovaginitis. It is important for clinicians to recognize the possibility of GAS vulvovaginitis in breastfeeding women with vaginal symptoms and consider the necessity of prompt antibiotic treatment.     

Protein Array Profiling of Tic Patient Sera Reveals a Broad Range and Enhanced Immune Response against Group A Streptococcus Antigens

The human pathogen Group A Streptococcus (Streptococcus pyogenes, GAS) is widely recognized as a major cause of common pharyngitis as well as of severe invasive diseases and non-suppurative sequelae associated with the existence of GAS antigens eliciting host autoantibodies. It has been proposed that a subset of paediatric disorders characterized by tics and obsessive-compulsive symptoms would exacerbate in association with relapses of GAS-associated pharyngitis. This hypothesis is however still controversial. In the attempt to shed light on the contribution of GAS infections to the onset of neuropsychiatric or behavioral disorders affecting as many as 3% of children and adolescents, we tested the antibody response of tic patient sera to a representative panel of GAS antigens. In particular, 102 recombinant proteins were spotted on nitrocellulose-coated glass slides and probed against 61 sera collected from young patients with typical tic neuropsychiatric symptoms but with no overt GAS infection. Sera from 35 children with neither tic disorder nor overt GAS infection were also analyzed. The protein recognition patterns of these two sera groups were compared with those obtained using 239 sera from children with GAS-associated pharyngitis. This comparative analysis identified 25 antigens recognized by sera of the three patient groups and 21 antigens recognized by tic and pharyngitis sera, but poorly or not recognized by sera from children without tic. Interestingly, these antigens appeared to be, in quantitative terms, more immunogenic in tic than in pharyngitis patients. Additionally, a third group of antigens appeared to be preferentially and specifically recognized by tic sera. These findings provide the first evidence that tic patient sera exhibit immunological profiles typical of individuals who elicited a broad, specific and strong immune response against GAS. This may be relevant in the context of one of the hypothesis proposing that GAS antigen-dependent induction of autoantibodies in susceptible individuals may be involved the occurrence of tic disorders.     

DNA methylase activity as a marker for the presence of a family of phage-like elements conferring efflux-mediated macrolide resistance in streptococci

Recently, two related chimeric genetic elements (Tn1207.3 and Phi10394.4) were shown to carry the macrolide efflux gene mef in Streptococcus pyogenes (group A streptococci [GAS]). The dissemination of elements belonging to the Tn1207.3/Phi10394.4 family in recent isolates of GAS, Streptococcus dysgalactiae subsp. equisimilis, Streptococcus pneumoniae, and Streptococcus agalactiae recovered in Portugal was surveyed. In total, 149 GAS, 18 S. pneumoniae, 4 S. dysgalactiae subsp. equisimilis, and 5 S. agalactiae isolates from infections, presenting the M phenotype of macrolide resistance and containing the mef gene, were screened for the presence of Tn1207.3/Phi10394.4 by PCR targeting open reading frames (ORFs) specific for these related elements. All the GAS isolates tested and one of the S. dysgalactiae subsp. equisimilis isolates carried Tn1207.3. However, neither of these elements was found in the isolates of the other streptococcal species. It was also noted that the DNAs of the isolates carrying Tn1207.3 were resistant to cleavage by the endonuclease SmaI. Cloning and expression of ORF12 of Tn1207.3 in Escherichia coli showed that it encoded a methyltransferase that rendered DNA refractory to cleavage by SmaI (M.Spy10394I). Using this characteristic as a marker for the presence of the Tn1207.3/Phi10394.4 family, we reviewed the literature and concluded that these genetic elements are widely distributed among tetracycline-susceptible GAS isolates presenting the M phenotype from diverse geographic origins and may have played an important role in the dissemination of macrolide resistance in this species.     

Dextromethorphan efficiently increases bactericidal activity, attenuates inflammatory responses, and prevents group a streptococcal sepsis

Group A streptococcus (GAS) is an important human pathogen that causes a wide spectrum of diseases, ranging from mild throat and skin infections to severe invasive diseases such as necrotizing fasciitis and streptococcal toxic shock syndrome. Dextromethorphan (DM), a dextrorotatory morphinan and a widely used antitussive drug, has recently been reported to possess anti-inflammatory properties. In this study, we investigated the potential protective effect of DM in GAS infection using an air pouch infection mouse model. Our results showed that DM treatment increased the survival rate of GAS-infected mice. Bacterial numbers in the air pouch were lower in mice treated with DM than in those infected with GAS alone. The bacterial elimination efficacy was associated with increased cell viability and bactericidal activity of air-pouch-infiltrating cells. Moreover, DM treatment prevented bacterial dissemination in the blood and reduced serum levels of the proinflammatory cytokines interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and IL-1β and the chemokines monocyte chemotactic protein 1 (MCP-1), macrophage inflammatory protein 2 (MIP-2), and RANTES. In addition, GAS-induced mouse liver injury was reduced by DM treatment. Taken together, DM can increase bacterial killing and reduce inflammatory responses to prevent sepsis in GAS infection. The consideration of DM as an adjunct treatment in combination with antibiotics against bacterial infection warrants further study.     

2011年北京市朝阳区儿童A组溶血性链球菌的emm基因分型及耐药性分析

目的 了解2011年北京市朝阳区儿童感染A组溶血性链球菌(GAS)的emm基因分型及对红霉素和克林霉素的耐药情况及耐药基因谱的特点。 方法 从猩红热或咽峡炎及扁桃体炎儿童患者的咽拭子培养分离获得71株GAS,应用PCR扩增emm基因及红霉素耐药基因mefA、ermA、ermB和转座子基因Tn916;采用E-test法进行药敏试验并分析耐药情况。 结果 北京市朝阳区儿童感染GAS的emm12.0基因型占87.4%,其次为emm1.0型(9.8%)、emm22.0型(1.4%)、emm75.0型(1.4%);GAS对红霉素和克林霉素的耐药率为100%和95.8%,两种药物的交叉耐药率为95.8%;耐药基因ermA、ermB、mefA和转座子基因Tn916的携带率分别为5.6%、90.1%、4.2%和90.1%。 结论 北京市朝阳区2011年儿童感染GAS的主要流行株为emm12.0型,对红霉素普遍具有较高的耐药率且与克林霉素之间存在显著的交叉耐药;ermB基因是决定本地区2011年儿童感染GAS对红霉素耐药的重要基因;而Tn916转座子基因在GAS菌株间耐药基因扩散中起重要作用。     

Streptococcal M proteins and their role as virulence determinants

Group A streptococci (GAS, Streptococcus pyogenes) are exclusive human pathogens that have been extensively studied for many decades. The spectrum of diseases caused by these bacteria ranges from uncomplicated and superficial to severe and invasive infections. In order to give rise to these complications, GAS have evolved a number of surface-bound and secreted virulence factors, of which the M proteins are probably the best characterized. Evidence has emerged that M proteins are multifunctional pathogenic determinants, and over the years many interactions between M proteins and the human host have been reported. The present review article aims to present a state-of-the-art overview of the most important virulence mechanisms employed by M proteins to trigger disease.     

The severity of Streptococcus pyogenes infections in children is significantly associated with plasma levels of inflammatory cytokines

Cytokines are intimately involved with the innate and adaptive immune response to bacterial infections. This study was designed to determine the expression of inflammatory cytokines in children by the severity of Streptococcus pyogenes (group A Streptococcus [GAS]) infections. The study population consisted of 16 invasive, 20 noninvasive, and 24 pharyngeal colonization, and 21 healthy controls. All children underwent the laboratory tests and cytokine measurement. GAS isolates were analyzed for emm gene typing. Patients with invasive GAS diseases had significantly higher interferon (IFN)-γ, interleukin (IL)-1β, IL-6, IL-8, IL-10, and IL-18 than those with noninvasive diseases, colonization, and healthy controls. There was no difference in tumor necrosis factor (TNF)-α, IL-12, and IL-2 levels among the groups. Elevated white blood cell counts and levels of C-reactive protein and C3 were detected only in patients with invasive diseases. emm1 and emm12 predominated in invasive disease and colonization. Children with invasive GAS infections exhibited significant up-regulation of plasma levels of IFN-γ, IL-1β, IL-6, IL-8, IL-10, and IL-18, and suppression of TNF-α and IL-12 during the acute phase of their illness. An exuberant cytokine response was associated with the severity of illness.     

The Simplexa™ Group A Strep Direct Assay: a sample-to-answer molecular assay for the diagnosis of group A streptococcal pharyngitis

The Simplexa? Group A Strep Direct assay is intended for use on the Integrated Cycler for detection of Group A Streptococcus (GAS) directly from throat swabs that have not undergone nucleic acid extraction. A prospective study of 1352 samples in 4 geographically diverse sites showed an overall prevalence of GAS of 15.4%. The assay demonstrated 97.4% sensitivity and 95.2% specificity versus culture. The positive predictive value compared to culture was 72.7%. However, 46 out of 57 discrepant samples were Group A Strep positive when tested using a bi-directional sequencing method illustrating the increased sensitivity of the assay compared to culture for detection of GAS. Rapid and accurate diagnosis of GAS allows for timely treatment to decrease complications of this prevalent organism that continues to cause substantial morbidity and mortality worldwide.