围产期孕妇泌尿生殖道无乳链球菌耐药性分析及临床意义

目的 了解围产期孕妇泌尿生殖道无乳链球菌感染及耐药分布为临床合理用药提供依据,并提出预防措施,以引起临床重视.方法 对门诊、住院围产期孕妇送检的泌尿生殖道标本进行培养鉴定,并对分离的无乳链球菌进行药敏试验,并用WHONET 5.5软件分析.结果 260株无乳链球菌药敏结果显示,对万古霉素、利奈唑胺、青霉素和头孢曲松的耐药率最低,对红霉素、克林霉素、左氧氟沙星的耐药率较高,分别为61.5％、57％和49.3％.结论 临床医生应重视对围产期孕妇无乳链球菌的检测,实验室应准确报告无乳链球菌药敏结果,对临床合理用药治疗无乳链球菌感染具有重要指导意义并可预防其危害性.     

围产期无乳链球菌携带状况及耐药性分析

目的探讨新疆乌鲁木齐市围产期无乳链球菌携带状况及耐药性,为临床合理使用抗菌药物提供依据。方法回顾性分析2014年1月-2016年11月围产期6 003例泌尿生殖道分泌物标本,采用法国梅里埃Vitek 2Compact全自动细菌鉴定和药敏系统检测,从中检出151株无乳链球菌,分析药敏、查阅其病历基本信息、新生儿出生状况等。结果 6 003例围产期泌尿生殖道标本中检出151株无乳链球菌,检出率为2.52%,其中≤35岁、35岁孕产妇中无乳链球菌感染率分别为2.55%、2.26%,两者相比差异无统计学意义(P0.05);民族中,汉族、维吾尔族、回族、哈萨克族中无乳链球菌感染率分别为2.70%、2.63%、2.18%、1.73%,相比差异无统计学意义(P0.05);37周感染无乳链球菌101例,且诊断胎膜早破有76例;孕1次感染无乳链球菌有90例,孕3次感染无乳链球菌有33例,且有20例曾有流产史;新生儿宫内感染中有1例感染无乳链球菌属于早发型。药敏结果中,无乳链球菌对氨苄西林、青霉素G敏感率分别为97.97%、98.63%;对红霉素、四环素、克林霉素和左氧氟沙星耐药率较高,分别为77.46%、72.85%、58.94%和54.30%。结论临床应重视在围产期对无乳链球菌的检测和耐药情况,合理使用抗生素,可有效地预防和治疗该菌的感染。     

无乳链球菌的研究进展

无乳链球菌亦称B群链球菌（Group B streptococcus,GBS）,一直是新生儿和女性生殖道受感染的重要病菌,尤其是新生儿时期的感染是危及生命的重要原因,其病发症包括败血症、肺炎和脑膜炎等。在成年妇女的阴道和直肠内有15％～40％可以检出无乳链球菌,因此,这类女性所分娩的新生儿感染该菌的机率会比较高。     

围产期生殖道菌群检测和B群链球菌筛查

目的 调查孕妇生殖道菌群情况,减少不良妊娠结果;筛查B群链球菌（GBS）定植状态,预防新生儿GBS病.方法 产前取阴道分泌物进行细菌培养,并对结果进行回顾性分析.结果 1464例孕妇阴道分泌物标本,872例乳酸杆菌和（或）少量其他菌种生长,占59.6%（872/1464）;592例乳酸杆菌未生长,检出“＋”以上生长菌株820株,其中194例有2种菌生长,34例有3种菌生长,占40.4%（592/1464）.共检出B群链球菌68株,检出率为4.6%（68/1464）.结论 围产期生殖道菌群种类复杂,耐药率高,妇幼保健工作人员应加强检测,采取切实可行的适宜技术,提供进一步的干预措施和保健服务.     

环介导等温扩增快速检测B群链球菌的临床应用

目的建立采用环介导等温扩增（LAMP）技术从临床标本中快速检测B群链球菌的方法。方法根据美国国家生物信息中心上提交的B群链球菌的cfb基因序列（登陆号X72754）设计特异LAMP引物,以热裂解法提取标本中细菌的DNA,然后以LAMP技术扩增cfb基因来鉴定其是否为B群链球菌。在采用LAMP技术检测B群链球菌的同时,以选择性培养法和PCR技术平行检测相同标本,并将3种方法的检测结果比较。结果在176例阴道拭子和176例直肠拭子中,选择性培养法检测到的B群链球菌例数为49和61、LAMP法检测到的B群链球菌例数为49和59,PCR法检测到的B群链球菌例数为48和58。以选择性培养法为金标准,LAMP法检测B群链球菌的灵敏度和特异度分别为96．7％和100％,PCR法检测B群链球菌的灵敏度和特异度分别为95．1％和100％。LAMP法检测B群链球菌的时间为2h左右,模拟菌株的检测结果显示该方法的最低检测限为10^2CFU／mL。结论该方法灵敏度高,特异性强,操作方便简单,适合从临床标本中快速检测B群链球菌。     

90株链球菌血清学及生化特征分群鉴定的研究

本文报告90株链球菌血清学和生化特征分群鉴定结果。研究结果表明,90株链球菌用血清学分群,属A群的63株,B群3株,C群12株,D群10株,G群2株。采用生化鉴定,对链球菌属的确认有参考价值。对分群鉴定无鉴别意义。我国过去沿用的非血清学推测性分群法,只适用于B、D群和绝大部分A群菌的鉴定,对C群和G群菌无鉴别意义。因此,在链球菌分群鉴定时,要采用血清学方法,对非血清学推测性分群需进一步完善,以提高其鉴定的准确性。     

孕妇产道B群链球菌的调查报告

由B群链球菌引起的脑膜炎、肺炎及败血症严重威胁新生儿的生命。其传染源为产妇产道。本文采集143例临产孕妇消毒前的产道拭子及32例新生儿口咽部拭子,经增菌后培养在羊血平板,用生化方法及SPA血清分群法对疑似链球菌体鉴定。孕妇标本B群链球菌的检出率为11.2%,其他链球菌有D群、G群及草绿色链球菌。新生儿标本几乎都无细菌生长。纲菌鉴定方法以SPA法优于生化法。笔者认为由于B群链球菌在临床上的重要性,该菌的分离培养及鉴定应在实验室受到重视。     

妊娠晚期阴道B族链球菌的感染对肠道菌群和妊娠结局的影响

目的探究妊娠晚期阴道B族链球菌(group B Streptococcus,GBS)的感染对肠道菌群和妊娠结局的影响。方法选取2018年3月至2019年11月大连市中心医院孕检并分娩的妊娠妇女744人为对象,调查并统计B族链球菌的感染率;筛选有和没有B族链球菌感染妊娠妇女各47人,调查不良妊娠结局的发生率;选取信息匹配的妊娠晚期阴道B族链球菌感染和未感染的妊娠妇女,采集粪便样本,提取菌群DNA,用16S rDNA方法分析菌群变化。结果744名妊娠妇女中B族链球菌检出49例,感染率为6.59%;B族链球菌感染组总的不良妊娠发生比例为76.6%,正常组发生比例为27.7%(χ^2=5.491,P<0.05)。B族链球菌感染组妊娠妇女胎膜早破(χ^2=16.177,P<0.01)、难产(χ^2=21.134,P<0.01)和羊水异常(χ^2=22.989,P<0.05)的发生率与未感染组比较显著增高。B族链球菌感染组妊娠妇女肠道菌群发生显著变化。结论妊娠晚期阴道B族链球菌的感染可能引起肠道菌群紊乱,增加不良妊娠结局。     

新型肺炎链球菌疫苗研究进展

肺炎链球菌(Streptococcus pneumoniae)是引发人类肺炎、中耳炎、脑膜炎的主要病原体。为了预防肺炎链球菌感染,人类已研制出了多种相关的疫苗。目前,常用23价肺炎球菌多糖疫苗(23-valent pneumococcal polysaccharide vaccine,PPV23)预防成人和2岁以上儿童肺炎链球菌的感染,用7价、10价、13价肺炎球菌结合疫苗来预防婴幼儿肺炎链球菌的感染。虽然荚膜多糖类疫苗能预防其所包含的肺炎链球菌血清型的感染,但非疫苗血清型的菌株还是可以在鼻咽部定植,并引起感染,而且结合疫苗研制工艺复杂、价格昂贵,在发展中国家使用还不普及。鉴于上述原因许多疫苗公司开始研发具有保护力强、价格低廉的新型疫苗。近年来,肺炎链球菌全细胞疫苗和肺炎链球菌纯化蛋白疫苗由于其血清非依赖性和较低的生产成本已成为人们关注的焦点。现对肺炎链球菌新型疫苗的研制及临床应用作一概述。     

11群肺炎链球菌荚膜多糖合成相关基因的分子生物学研究

目的利用分子生物学方法,研究7株11群肺炎链球菌荚膜多糖合成相关基因(cps loci)。方法根据11群肺炎链球菌荚膜多糖合成相关基因设计合成5对特异性引物,以7株肺炎链球菌基因组DNA作为模板进行PCR扩增,并对扩增产物进行序列测定及基因序列比对,确定其血清型。多位点序列分型(multilocus sequence typing,MLST)技术分析7株11群肺炎链球菌序列型(ST)。采用相邻合并分析(neighbour-joining analysis),根据MLST的7个管家基因和cps基因分别绘制系统发育树。结果根据wcw C、gct和wcj E等3个基因产物确定5株原11A型肺炎链球菌为11A型,无11E型;根据wcwR和gct等2个基因产物确定2株原11B型肺炎链球菌为11B型。获得7株不包括4个合成调控基因(wzg、wzh、wzd和wze)的11群肺炎链球菌cps loci,长度为11～12 kb,11A型具有12个开放式阅读框(ORF),11B型具有11个ORF。5株11A型肺炎链球菌部分cps基因序列差异较大; 2株11B型肺炎链球菌部分cps基因序列相似性高于99%。根据MLST分析发现3种新的ST型。根据MLST的7个管家基因绘制的系统发育树和cps基因绘制的系统发育树差异很大。结论从分子水平上确定了11A和11B血清型。获得了5株11A型和2株11B型肺炎链球菌ST型和部分荚膜多糖合成相关基因(cps loci),完善了11群肺炎链球菌的菌种档案。     

Novel protein vaccine candidates against Group B streptococcal infection identified using alkaline phosphatase fusions

Using an alkaline phosphatase-based genetic screening method, we identified a number of proteins that are potentially located on the outer surface of Group B streptococcus (Streptococcus agalactiae). In an enzyme-linked immunosorbent assay, antisera raised against two of the proteins, the streptococcal yutD homologue and a subunit of an ABC transporter, recognised clinically important serotypes of Group B streptococcus. In a neonatal rat model, purified IgG from the sera conferred significant levels of protection against a lethal challenge infection. The proteins identified show potential as protein subunit candidates for vaccines against Group B streptococcal disease in neonates.     

Comparative evaluation of Strepto B ID chromogenic medium and Granada media for the detection of Group B streptococcus from vaginal samples of pregnant women

Two types of selective media, the chromogenic medium Strepto B ID® and two non-chromogenic media Strepto B agar® and the Granada® medium, were tested and compared to blood agar plates (BAP) for screening of Group B streptococcus vaginal colonization in pregnant women. All tested media were comparable in terms of sensitivity however, their use in routine laboratories may markedly facilitate the rapid detection of GBS in vaginal samples.     

Macrophages recognize streptococci through bacterial single-stranded RNA

Group B streptococcus (GBS) is a leading cause of both neonatal sepsis and meningitis, two diseases that are characterized by inflammation. However, the manner in which GBS organisms are recognized by monocytes and macrophages is poorly understood. In this study, we report that the recognition of GBS and other Gram-positive bacteria by macrophages and monocytes relies on bacterial single-stranded RNA (ssRNA). ssRNA interacts with a signalling complex, which comprises the Toll-like receptor adaptors MyD88 and UNC-93B, but not the established MyD88-dependent ssRNA sensors. The role of ssRNA in the recognition of Gram-positive bacteria--leading to the induction of inflammatory cytokines--has potential implications for sepsis pathogenesis, diagnosis and treatment.     

Group B streptococcus tricuspid endocarditis presenting with arthralgia in a postpartum woman: a case report

ABSTRACT: INTRODUCTION: Infective endocarditis presenting with arthralgia is rare. Group B streptococcus tricuspidendocarditis as a postpartum complication is even rarer. The present case is an example ofboth. CASE PRESENTATION: We report the case of a 30-year-old Caucasian woman who presented with painful swelling ofher wrists and ankles. CONCLUSION: Even when the clinical presentation of systemic inflammation is more suggestive of aprimary rheumatological disorder, it is important to remember that bacterial infection canalso present in this manner. Group B streptococcus tricuspid valve endocarditis is a rare, butrecognized, postpartum complication.     

Neurological Complications after Neonatal Bacteremia: The Clinical Characteristics,Risk Factors,and Outcomes

Background

Neonates with bacteremia are at risk of neurologic complications. Relevant information warrants further elucidation.

Study Design

This was a retrospective cohort study of neonates with bacteremia-related neurologic complications (BNCs) in a tertiary-level neonatal intensive care unit (NICU). A systemic chart review was performed conducted to identify clinical characteristics and outcomes. A cohort of related conditions was constructed as the control group. Logistic regression analysis was used to identify independent risk factors for BNC.

Results

Of 1037 bacteremia episodes, 36 (3.5%) had BNCs. Twenty-four cases of BNCs were related to meningitis, five were presumed meningitis, and seven occurred after septic shock. The most common causative pathogens were Group B streptococcus (41.7%) and E. coli (16.7%). The major BNCs consisted of seizures (28), hydrocephalus (20), encephalomalacia (11), cerebral infarction (7), subdural empyema (6), ventriculitis (8), and abscess (4). Eight (22.8%) neonates died and six (16.7%) were discharged in critical condition when the family withdrew life-sustaining treatment. Among the 22 survivors, eight had neurologic sequelae upon discharge. After multivariate logistic regression analysis, neonates with meningitis caused by Group B streptococcus (adjusted odds ratio [OR]: 8.90, 95% confidence interval [CI]: 2.20–36.08; p = 0.002) and combined meningitis and septic shock (OR, 5.94; 95% CI: 1.53–23.15; p = 0.010) were independently associated with BNCs.

Conclusions

Neonates with bacteremia-related neurologic complications are associated with adverse outcomes or sequelae. Better strategies aimed at early detection and reducing the emergence of neurologic complications and aggressive treatment of Group B streptococcus sepsis are needed in neonates with meningitis and septic shock.     

Meningitis and bacteremia by nonhemolytic Group B Streptococcus strain: A whole genome analysis

Group B streptococcus (GBS) is a leading cause of neonatal infections. Most isolates are β-hemolytic, and their activity is considered to be pivotal for GBS pathogenicity. We report a case of a neonate with meningitis caused by nonhemolytic GBS. The patient developed meningitis 3 days after birth. Genotyping was performed and the characteristics of the strain (GCMC97051) identified by whole genome sequence using next generation sequencing. GCMC97051 possesses genetic alterations such as disruption of cylA by IS1381A insertion and a frameshift mutation in cylE, resulting in a lack of hemolysis. Thus, nonhemolytic GBS can retain the potential to cause invasive infections.     

A streptococcal penicillin-binding protein is critical for resisting innate airway defenses in the neonatal lung

Group B streptococcus (GBS) is a major cause of neonatal pneumonia. The early interactions between innate airway defenses and this pathogen are likely to be a critical factor in determining the outcome for the host. The surface-localized penicillin-binding protein (PBP)1a, encoded by ponA, is known to be an important virulence trait in a sepsis model of GBS infection that promotes resistance to neutrophil killing and more specifically to neutrophil antimicrobial peptides (AMPs). In this study, we used an aerosolization model to explore the role of PBP1a in evasion of innate immune defenses in the neonatal lung. The ponA mutant strain was cleared more rapidly from the lungs of neonatal rat pups compared with the wild-type strain, which could be linked to a survival defect in the presence of alveolar macrophages (AM). Rat AM were found to secrete beta-defensin and cathelicidin AMP homologues, and the GBS ponA mutant was more susceptible than the wild-type strain to killing by these peptides in vitro. Collectively, our observations suggest that PBP1a-mediated resistance to AM AMPs promotes the survival of GBS in the neonatal lung. Additionally, AM are traditionally thought to clear bacteria through phagocytic uptake; our data indicate that secretion of AMPs may also participate in limiting bacterial replication in the airway.     

Rapid detection of the "highly virulent" group B Streptococcus ST-17 clone

Group B streptococcus (GBS) is a leading cause of neonatal morbidity and mortality. Multilocus sequence typing (MLST) revealed that the sequence type ST-17 defines a "highly virulent" serotype III clone strongly associated with neonatal invasive infections. Our aim was to identify a target sequence enabling rapid, simple, and specific detection of this clone by a real-time PCR assay. Conventional methods for DNA manipulation and gene analyses were used to characterize the gbs2018 gene variant specific for ST-17 clone and to design ST-17- and GBS-specific primers. Conventional and real-time PCR assays were developed to detect GBS and ST-17 clones in bacterial cultures and directly on clinical samples. One hundred and fifty-six French GBS strains from various geographical areas in France isolated between 1990 and 2005 were screened by PCR with ST-17-specific primers. Forty strains were positive, and all were validated by MLST as ST-17. A representative sampling of 49 ST-17-PCR-negative strains was confirmed by MLST as non-ST-17. Real-time PCR was further used to directly test 85 vaginal samples. Among these, 13 were GBS-positive, and one was identified as ST-17. The association between strain invasiveness and ST-17 lineage in neonates with late onset disease was highly significant: 78% (P<0.0001) of strains isolated were ST-17. In conclusion, an ST-17-specific gbs2018 allele was identified and used to develop a sensitive and specific rapid-screening molecular assay for identifying ST-17 "highly virulent" GBS. Using this technique, accurate identification of women and neonates colonized by ST-17 can be readily achieved within less than 2 h.     

New DNA-based PCR approaches for rapid real-time detection and prevention of group B streptococcal infections in newborns and pregnant women

Group B streptococci (GBS) are an important cause of neonatal sepsis and meningitis, and maternal infection. Although the pathogenesis of GBS infection is not well understood, several virulence factors have been identified. Two prevention strategies have been proposed: chemoprophylaxis and immunoprophylaxis. Implementation of selective intrapartum chemoprophylaxis on the basis of either screening or risk assessment has led to a substantial decrease in the morbidity and mortality of GBS disease in both mothers and infants. Penicillin remains the antibiotic of choice with no reported resistant GBS so far, whereas resistance of 10-20% of GBS to erythromycin and clindamycin has been reported in North America. Chemoprophylaxis based on screening requires optimal detection methods for GBS, which involve selective broth culture of combined vaginal and anal samples. Other conventional methods are useful for rapid identification of heavily colonised women, but are unreliable for the detection of light GBS colonisation because of poor sensitivity. GBS-specific polymerase chain reaction (PCR) assays using real-time PCR coupled with fluorescence-labelling technology offer powerful tools for sensitive and specific, yet rapid (less than 1 h), detection of GBS directly from clinical specimens at the time of delivery. The application of these assays to the current prevention strategies will simplify the prevention practice and rationalise the use of antibiotics. Immunoprophylaxis relies on the development of new vaccines against GBS, and active research is being conducted in this area.     

Congenital asplenia and group B streptococcus sepsis in the adult: case report and review of the literature

Asplenia is associated with an increased incidence of fatal and life-threatening sepsis caused by encapsulated pathogens. Isolated congenital asplenia is a very rare condition, with only 33 cases reported in the literature. The authors report another case of this condition complicated by overwhelming Group B streptococcus sepsis secondary to paronychia that was managed successfully.