Skin infection by Mycobacterium marinum – diagnostic and therapeutic challenge

The number of skin infections caused by atypical mycobacteria has increased in recent decades. They usually appear after contact with wounds and interruptions in the integrity of the skin. The present report describes a case of cutaneous infection by Mycobacterium marinum, in a young, immunocompetent patient, with a prolonged evolution, diagnosed through a skin lesion culture (from a spindle biopsy of the skin). The patient was treated with multidrug therapy, including clarithromycin, doxycycline, and rifampicin, due to the lesion extent, with satisfactory results. A brief review of the literature is also provided.     

The T2Bacteria Assay Is a Sensitive and Rapid Detector of Bacteremia That Can Be Initiated in the Emergency Department and Has Potential to Favorably Influence Subsequent Therapy

BackgroundBacteremia causes a major worldwide burden, in terms of financial and productivity costs, as well the morbidity and mortality it can ultimately cause. Proper treatment of bacteremia is a challenge because of the species-dependent response to antibiotics. The T2Bacteria Panel is a U.S. Food and Drug Administration–cleared and culture-independent assay for detection of bacteremia, including common ESKAPE pathogens—Escherichia coli, Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa—and provides species identification in as little as 3.6 h directly from blood.ObjectiveOur aim was to evaluate the T2Bacteria assay performance and potential to affect patient care in the emergency department (ED).MethodsED patients from a Louisiana and Florida center were enrolled as part of the T2Bacteria Panel clinical study, which was prospective and noninterventional. Blood samples for blood culture (BC) and T2Bacteria were matched in time and anatomic location.ResultsData from 137 ED patients were evaluated. Relative to BC, T2Bacteria showed 100% positive percent agreement and 98.4% negative percent agreement. In addition, for species on the T2Bacteria Panel, the T2Bacteria assay detected 25% more positives associated with infection, and on average identified the infectious species 56.6 h faster. The T2Bacteria assay covered 70.5% of all species detected by BC. Finally, relative to actual care, the T2Bacteria assay could have potentially focused therapy in 8 patients, reduced time to a species-directed therapy in 4 patients, and reduced time to effective therapy in 4 patients.ConclusionsIn this ED population, the T2Bacteria assay was a rapid and sensitive detector of bacteremia from common ESKAPE pathogens and showed the theoretical potential to influence subsequent patient therapy, ranging from antibiotic de-escalation to faster time to effective therapy.     

Organoids in modelling infectious diseases

Approaches based on animal and two-dimensional (2D) cell culture models cannot ensure reliable results in modeling novel pathogens or in drug testing in the short term; therefore, there is rising interest in platforms such as organoids. To develop a toolbox that can be used successfully to overcome current issues in modeling various infections, it is essential to provide a framework of recent achievements in applying organoids. Organoids have been used to study viruses, bacteria, and protists that cause, for example, respiratory, gastrointestinal, and liver diseases. Their future as models of infection will be associated with improvements in system complexity, including abilities to model tissue structure, a dynamic microenvironment, and coinfection.Teaser.Organoids are a flexible tool for modelling viral, bacterial and protist infections. They can provide fast and reliable information on the biology of pathogens and in drug screening, and thus have become essential in combatting emerging infectious diseases.     

Chlamydia trachomatis: Cell biology,immunology and vaccination

Chlamydia trachomatis is the causative agent of a highly prevalent sexually transmitted bacterial disease and is associated with a number of severe disease complications. Current therapy options are successful at treating disease, but patients are left without protective immunity and do not benefit the majority asymptomatic patients who do not seek treatment. As such, there is a clear need for a broad acting, protective vaccine that can prevent transmission and protect against symptomatic disease presentation. There are three key elements that underlie successful vaccine development: 1) Chlamydia biology and immune-evasion adaptations, 2) the correlates of protection that prevent disease in natural and experimental infection, 3) reflection upon the evidence provided by previous vaccine attempts. In this review, we give an overview of the unique intra-cellular biology of C. trachomatis and give insight into the dynamic combination of adaptations that allow Chlamydia to subvert host immunity and survive within the cell. We explore the current understanding of chlamydial immunity in animal models and in humans and characterise the key immune correlates of protection against infection. We discuss in detail the specific immune interactions involved in protection, with relevance placed on the CD4+ T lymphocyte and B lymphocyte responses that are key to pathogen clearance. Finally, we provide a timeline of C. trachomatis vaccine research to date and evaluate the successes and failures in development so far. With insight from these three key elements of research, we suggest potential solutions for chlamydial vaccine development and promising avenues for further exploration.     

Recombinant Mycobacterium bovis bacillus Calmette–Guérin expressing Ag85B-IL-7 fusion protein enhances IL-17A-producing innate γδ T cells

Interleukin 7 (IL-7) has an important function in the development and maintenance of IL-17A+ γδ T cells. We here constructed a recombinant Mycobacterium bovis bacillus Calmette–Guérin expressing antigen 85B (Ag85B)-IL-7 fusion protein (rBCG-Ag85B-IL-7). The Ag85B-IL-7 fusion protein and IL-7 were detected in the bacterial lysate of rBCG-Ag85B-IL-7. rBCG-Ag85B-IL-7 was the same in number as control rBCG expressing Ag85B (rBCG-Ag85B) in the lung at the early stage after intravenous inoculation, whereas the numbers of IL-17A+ γδ T cells and Ag-specific Th1 cells were significantly higher in the lungs of mice inoculated with rBCG-Ag85B-IL-7 than those inoculated with rBCG-Ag85B. The Ag-specific Th1 cell response was impaired in mice lacking IL-17A+ γδ T cells after inoculation with rBCG-Ag85B-IL-7. Thus, rBCG-Ag85B-IL-7 increases the pool size of IL-17A+ γδ T cells, which subsequently augment the Th1 response to mycobacterial infection.     

冲洗液对超声根管预备抗菌效果的影响

目的研究生理盐水、EDTA、次氯酸钠、口泰与超声波联合应用杀灭感染根管内厌氧菌的效果。方法将100例慢性根尖周炎患者共100颗患牙随机分为常规组、生理盐水组、EDTA组、次氯酸钠组、口泰组5组,每组各20颗患牙,常规组用常规法手持器械根管预备并分别用3%双氧水和生理盐水常规针筒式冲洗根管,后四组均用超声法进行根管预备并分别以生理盐水、EDTA、次氯酸钠、口泰作为超声冲洗液,根管预备前后分别取样进行厌氧培养。结果次氯酸钠组和口泰组其厌氧菌减少程度均显著大于生理盐水组(P<0.01),明显大于EDTA组(P<0.05);生理盐水组和EDTA组之间其厌氧菌的减少程度无显著性差异(P>0.05);次氯酸钠组和口泰组之间其厌氧菌减少程度无显著性差异(P>0.05)。结论口泰与超声波联合应用可有效杀灭感染根管内厌氧菌,其抗菌效果与次氯酸钠相近似。     

不同消毒剂对藻酸钾印模表面细菌消毒效果比较

目的 使用不同消毒剂浸泡消毒污染口腔印模，观察其消毒效果。方法 实验组81个试件按所染菌种分为金黄色葡萄球菌组，血液链球菌组，白色念珠菌组，每组27个试件。各菌组再按消毒剂不同分三组。每组9个试件。用250ml无菌蒸馏水冲洗后分别浸没于2％强化中性戊二醛，0．1％碘伏，0．5％次氯酸中，于5min。10min，15min各取出3个试件。阳性对照组，每组6个试件。分别染菌后3个试件冲洗，3个试件不冲。阴性对照组，每组2个试件。取印模后不染菌。各组浸于中和液中，洗下余菌。培养并计数。结果 ①冲洗可以使印模表面的附着菌数平均减少95．15％。②2％戊二醛消毒5min对三种菌的消毒效果可达100％。0．1％碘伏浸泡消毒5min对三种菌的消毒效果可达99．99％。0．5％次氯酸消毒10min可达到消毒效果。结论 ①冲洗可以部分去除印模表面附着菌。但迭不到消毒的效果，仍应对印模进行消毒处理。②2％戊二醛消毒5min，0．1％碘伏，0．5％次氯酸消毒10min对沾染白色念珠菌。金黄色葡萄球菌，血链球菌的印模可达到消毒效果。