环介导恒温扩增法快速检测海产品中的副溶血弧菌

副溶血弧菌广泛分布于海水或海产品中,人类摄入或接触污染的水源和食物易引起感染。近年来,有关致病性弧菌引起腹泻的报道逐渐增多,但GB标准的细菌学诊断方法检测周期长达1周左右,而且操作较为复杂,难以满足控制疾病暴发和传播的需要,就这一现状,建立了一套不仅快速、准确,而且操作简便、不依赖昂贵仪器的检测方法,应用于海产品中副溶血弧菌快速检测。采用环介导恒温扩增方法(LAMP),针对副溶血弧菌的gyrB基因设计特异引物,进行恒温扩增。使用该方法最低检出限达到101CFU/mL,灵敏度可以达到0.1pg副溶血弧菌基因组DNA,为海产品中副溶血弧菌的检测提供了一个新的辅助方法。     

VITEK 2 Compact 联合MALDI-TOF MS、16S rDNA基因测序对1株类志贺邻单胞菌的对比鉴定报告

类志贺邻单胞菌属于肠杆菌科的邻单胞菌属,是革兰阴性杆菌,为人类条件致病菌,该菌首先发现于胃肠道,但无明确证据证实其具有肠致病性,仅个别例证报道其可引起败血症和肠胃炎。霍乱弧菌属于弧菌属,革兰阴性杆菌,血清型O1群和O139群是甲类传染病霍乱的病原菌,通过侵袭力和霍乱肠毒素致病,可引起严重的呕吐和腹泻;而血清型非O1/O139群血流感染在国内偶见报道。本文报告1例在湘潭市中心医院就诊的慢性肝病患者无明显诱因出现腹痛、腹泻伴呕吐,且畏寒、寒战,血培养检出1株革兰阴性杆菌,初期经VITEK 2 Compact 全自动细菌鉴定及药敏分析系统鉴定为霍乱弧菌;但后经基质辅助激光解析电离飞行时间质谱技术(matrix-assisted laser desorption/ionization time-of-flight mass spectrometry,MALDI-TOF MS)和16S rDNA基因测序,均确认为类志贺邻单胞菌。根据药敏试验结果,予哌拉西林/他唑巴坦抗感染,输血、护肝等对症治疗后好转出院,随访无复发。本报告结果提示,当Vitek-2 Compact将待检样本鉴定为霍乱弧菌等临床少见菌时,仍须结合细菌菌落形态、辅助生化试验以及患者的临床情况进行综合判断,必要时可采用质谱、基因测序等其他检测手段进行复核。     

Vibrio vulnificus. Hazard on the half shell.

Vibrio vulnificus is an extremely invasive gram-negative bacillus that causes bacteremia and shock. It should be suspected in any patient who is immunocompromised or has liver disease or hemochromatosis. Reduced gastric acidity may also increase the risk of infection if a patient presents with a history of ingesting raw shellfish (especially oysters) or trauma in brackish waters and skin lesions. Patients most commonly present with one of three clinical syndromes: primary septicemia, wound infection, or gastroenteritis. Treatment includes aggressive wound debridement, antibiotic therapy, and supportive care. Rapidly diagnosing and promptly initiating therapy are critical because V vulnificus infection is rapidly progressive and mortality approaches 100% if septic shock occurs.     

Hepatitis B virus-induced lipid alterations contribute to natural killer T cell-dependent protective immunity

In most adult humans, hepatitis B is a self-limiting disease leading to life-long protective immunity, which is the consequence of a robust adaptive immune response occurring weeks after hepatitis B virus (HBV) infection. Notably, HBV-specific T cells can be detected shortly after infection, but the mechanisms underlying this early immune priming and its consequences for subsequent control of viral replication are poorly understood. Using primary human and mouse hepatocytes and mouse models of transgenic and adenoviral HBV expression, we show that HBV-expressing hepatocytes produce endoplasmic reticulum (ER)-associated endogenous antigenic lipids including lysophospholipids that are generated by HBV-induced secretory phospholipases and that lead to activation of natural killer T (NKT) cells. The absence of NKT cells or CD1d or a defect in ER-associated transfer of lipids onto CD1d results in diminished HBV-specific T and B cell responses and delayed viral control in mice. NKT cells may therefore contribute to control of HBV infection through sensing of HBV-induced modified self-lipids.     

Problems related to the diagnosis of Chagas' disease

Trypanosoma cruzi may be transmitted to a susceptible human through different routes: a superficial lesion in the skin, such as a scraping of the small wound produced by the hematophagous triatomid bug vector, which becomes infected with its contaminated feces; the placenta, from the infected mother to the product of conception; a transfusion from an infected donor, or even by ingestion of diverse foods infected or contaminated with the parasite. Whichever may be the transmission of the protozoon, it is advisable to have in mind that it is able to produce an asymptomatic or a symptomatic infection, being possible in both cases, using appropriated methods, to detect the T. cruzi and/or the antibodies generated. From the clinical stand-point, Chagas' Disease may present itself as acute or as a chronic disease. Habitually, the acute disease is characterized by general involvement, fever, hepato-splenomegaly, polidenopathy, and occasionally myocarditis and/or encephalitis, whereas, the chronic form of the disease is characterized by presenting itself in an isolated way or combined, chronic myocardiopathy, megaesophagous or megacolon. At any rate, the problems center in the possibility of a reasonable diagnostic assurance which permits the adoption of adequate therapeutic measures. Some facts, which may help to confront these problems are: a) The epidemiological antecedents (origin in an endemic area, personal knowledge of the vector or of being bitten by it, whether the mother or other relatives are affected by the disease, etc.).(ABSTRACT TRUNCATED AT 250 WORDS)     

Chagas disease: Present status of pathogenic mechanisms and chemotherapy

There are approximately 7.8 million people in Latin America, including Chile, who suffer from Chagas disease and another 28 million who are at risk of contracting it. Chagas is caused by the flagellate protozoan Trypanosoma cruzi. It is a chronic disease, where 20%-30% of infected individuals develop severe cardiopathy, with heart failure and potentially fatal arrhythmias. Currently, Chagas disease treatment is more effective in the acute phase, but does not always produce complete parasite eradication during indeterminate and chronic phases. At present, only nifurtimox or benznidazole have been proven to be superior to new drugs being tested. Therefore, it is necessary to find alternative approaches to treatment of chronic Chagas. The current treatment may be rendered more effective by increasing the activity of anti-Chagasic drugs or by modifying the host's immune response. We have previously shown that glutathione synthesis inhibition increases nifurtimox and benznidazole activity. In addition, there is increasing evidence that cyclooxygenase inhibitors present an important effect on T. cruzi infection. Therefore, we found that aspirin reduced the intracellular infection in RAW 264.7 cells and, decreased myocarditis extension and mortality rates in mice. However, the long-term benefit of prostaglandin inhibition for Chagasic patients is still unknown.     

DNA环介导恒温扩增技术快速检测霍乱弧菌

霍乱弧菌是一种重要的食源性致病菌,主要引起急性肠道传染病,其快速检测具有重要意义。根据霍乱弧菌的mdh管家基因序列,设计2对特异性检测引物,利用DNA环介导恒温扩增技术(Loop-mediated isothermal amplification,LAMP),经反应体系优化,成功建立了霍乱弧菌的LAMP快速检测方法。该方法最佳反应温度为65℃,60min完成检测,对培养菌的检测限为25CFU/mL,污染食品中霍乱弧菌的检测限为32CFU/g。对33株同种或近源细菌进行LAMP检测,仅霍乱弧菌得到阳性扩增。LAMP方法实践应用结果表明,对1057份虾、蟹、牡蛎、肉类、人腹泻物等样本进行检测,共检出85份阳性,与国际标准(ISO TS21872-1-2007)检测结果的符合率为100%。结果表明,本研究建立的霍乱弧菌LAMP检测方法特异性强、灵敏度高、操作简便,有利于霍乱弧菌疫情的监测。     

Chagas' disease and AIDS

Chagas' disease caused by Trypanosoma cruzi is an opportunistic infection in the setting of HIV/AIDS. Some individuals with HIV and chronic T. cruzi infection may experience a reactivation, which is most commonly manifested by meningoencephalitis. A reactivation myocarditis is the second most common manifestation. These presentations may be difficult to distinguish from toxoplasmosis in individuals with HIV/AIDS. The overlap of HIV and Trypanosoma cruzi infection occurs not only in endemic areas but also in non-endemic areas of North America and Europe where the diagnosis may be even more difficult. The pathological features, diagnosis and the role of cytokines in the pathogenesis of the disease are discussed.     

Burkholderia cepacia Complex as Human Pathogens

Although sporadic human infection due to Burkholderia cepacia has been reported for many years, it has been only during the past few decades that species within the B. cepacia complex have emerged as significant opportunistic human pathogens. Individuals with cystic fibrosis, the most common inherited genetic disease in Caucasian populations, or chronic granulomatous disease, a primary immunodeficiency, are particularly at risk of life-threatening infection. Despite advances in our understanding of the taxonomy, microbiology, and epidemiology of B. cepacia complex, much remains unknown regarding specific human virulence factors. The broad-spectrum antimicrobial resistance demonstrated by most strains limits current therapy of infection. Recent research efforts are aimed at a better appreciation of the pathogenesis of human infection and the development of novel therapeutic and prophylactic strategies.     

Shell disease: abnormal conchiolin deposit in the abalone Haliotis tuberculata

Shell disease in the abalone Haliotis tuberculata L. is characterized by a conchiolin deposit on the inner surface of the shell. The gross clinical signs appear similar to the Brown Ring Disease (BRD) of clams. BRD has been extensively described in clams and is known to be responsible for severe mortalities and the collapse of the clam aquaculture industry in western France. In the clam, it was found to be caused by the infection of the mantle by Vibrio tapetis. Brown protein deposits have been observed in various abalone species around the world; some of these have been associated with a fungal infection in New Zealand, but the ones described here are similar to bacterial infections observed in clams. Larger animals appeared to be more affected by the disease, and a positive correlation of the number of successive infections found in the shells with the level of infestation of the shell by borers suggests that boring polychaetes and sponges may be vectors of the disease, or that the parasite infestation may increase the susceptibility of the animal to this infection. There is no evidence, however, that this infection causes mortality in abalone.     

The cellular paradigm of chlamydial pathogenesis

Diseases caused by Chlamydia are based on intense and chronic inflammation elicited and maintained by reinfection or persistent infection. The traditional view in the field is that disease is mediated by antigen-dependent delayed-type hypersensitivity or autoimmunity. This immunological paradigm has served as the basis for years of chlamydial research but the mechanism or the antigen that causes pathology has yet to be unequivocally revealed. Recent research on responses elicited in Chlamydia-infected cells defines a new direction for our understanding of this microorganism-host interaction and provides the basis for a reassessment of disease mechanisms. Chlamydia-infected non-immune mammalian cells produce proinflammatory chemokines, cytokines, growth factors and other cellular modulators. This cellular response to infection supports an alternative hypothesis for chlamydial pathogenesis: the inflammatory processes of chlamydial pathogenesis are elicited by infected host cells and are necessary and sufficient to account for chronic and intense inflammation and the promotion of cellular proliferation, tissue remodeling and scarring, the ultimate cause of disease sequelae.     

Helicobacter pylori attaches to NeuAc alpha 2,3Gal beta 1,4 glycoconjugates produced in the stomach of transgenic mice lacking parietal cells

Helicobacter pylori infection of the human stomach is associated with altered acid secretion, loss of acid-producing parietal cells, and, in some hosts, adenocarcinoma. We have used a transgenic mouse model to study the effects of parietal cell ablation on H. pylori pathogenesis. Ablation results in amplification of the presumptive gastric epithelial stem cell and its immediate committed daughters. The amplified cells produce sialylated oncofetal carbohydrate antigens that function as receptors for H. pylori adhesins. Attachment results in enhanced cellular and humoral immune responses. NeuAc alpha 2,3Gal beta 1,4 glycoconjugates may not only facilitate persistent H. pylori infection in a changing gastric ecosystem, but by promoting interactions with lineage progenitors and/or initiated cells contribute to tumorigenesis in patients with chronic atrophic gastritis.     

Plasmid-deficient Chlamydia muridarum fail to induce immune pathology and protect against oviduct disease

Chlamydia trachomatis is the most prevalent sexually transmitted bacterial infection in the world. In women, genital infection can cause endometritis and pelvic inflammatory disease with the severe sequelae of ectopic pregnancy or infertility. Chlamydia sp. do not damage tissues directly, but induce an injurious host inflammatory response at the infected site. In the murine model of genital disease with Chlamydia muridarum, TLR2 plays a role in both early production of inflammatory mediators and development of chronic oviduct pathology. We report the results of studies with plasmid-cured C. muridarum mutants that retain the ability to infect the murine genital tract, but fail to cause disease in the oviduct. These mutants do not stimulate TLR2-dependent cytokine production in mice, nor in innate immune cells or epithelial cells in vitro. They induce an effective Th1 immune response, with no evidence for Th1-immune-mediated collateral tissue damage. Furthermore, mice previously infected with the plasmid-deficient strains are protected against oviduct disease upon challenge with virulent C. muridarum. If plasmid-cured derivatives of human C. trachomatis biovars exhibit similar phenotypic characteristics, they have the potential to serve as vaccines to prevent human disease.     

Phagocyte NADPH oxidase,chronic granulomatous disease and mycobacterial infections

Infection of humans with Mycobacterium tuberculosis remains frequent and may still lead to death. After primary infection, the immune system is often able to control M. tuberculosis infection over a prolonged latency period, but a decrease in immune function (from HIV to immunosenescence) leads to active disease. Available vaccines against tuberculosis are restricted to BCG, a live vaccine with an attenuated strain of M. bovis. Immunodeficiency may not only be associated with an increased risk of tuberculosis, but also with local or disseminated BCG infection. Genetic deficiency in the reactive oxygen species (ROS)‐producing phagocyte NADPH oxidase NOX2 is called chronic granulomatous disease (CGD). CGD is among the most common primary immune deficiencies. Here we review our knowledge on the importance of NOX2‐derived ROS in mycobacterial infection. A literature review suggests that human CGD patient frequently have an increased susceptibility to BCG and to M. tuberculosis. In vitro studies and experiments with CGD mice are incomplete and yielded – at least in part – contradictory results. Thus, although observations in human CGD patients leave little doubt about the role of NOX2 in the control of mycobacteria, further studies will be necessary to unequivocally define and understand the role of ROS.     

Clinical Manifestations and the Natural History of HIV Infection in Adults

The clinical expression of infection with the human immunodeficiency virus (HIV) appears increasingly complex. It includes manifestations due to opportunistic diseases, as well as illness directly caused by HIV itself. Neurologic disease may include involvement of the brain, spinal cord and peripheral nerves and is probably directly caused by HIV, as is lymphocytic interstitial pneumonia. The etiology of the chronic diarrhea and a papular pruritic skin eruption associated with HIV infection is unclear. Between 2% and 8% of HIV-infected persons progress to the acquired immunodeficiency syndrome (AIDS) per year, with no apparent decrease in the rate of disease progression over time. A chronically activated state secondary to chronic microbial antigenic exposure may increase both the susceptibility to HIV infection and development of disease. Increased HIV gene expression, followed by persistent antigenemia, appear to be triggering factors in clinical deterioration. The role, if any, of environmental and/or genetic cofactors remains unclear.     

Paracoccidioidomycosis

Paracoccidioidomycosis is the most frequent endemic mycosis in South America. The infection is more prevalent in rural workers, and recent epidemiologic data suggest that changes in agricultural practices (such as a decrease in coffee plantations and an increase in sugar cane plantations) may result in a reduction in the incidence of infection. After being inhaled, Paracoccidioides brasiliensis usually causes a benign and transient pulmonary infection that may progress to an acute form or, more frequently, reactivate later as a chronic disease. The diagnosis is usually made by direct examination and culture of clinical specimens; serologic tests may be of help, especially antigen detection. The drug of choice for the chronic form is oral itraconazole, whereas patients with more severe forms may be treated with intravenous amphotericin B or sulfamethoxazoletrimethoprim. The newer azole voriconazole is also effective, and it may be a good alternative because it can be given by oral or intravenous route.     

TOXOPLASMOSIS—The Protean Manifestations of the Condition and Their Significance in Pregnancy and in Newborn Infants

Toxoplasmosis is a relatively common and generally mild parasitic infection which can, however, produce fatal and crippling complications under certain conditions — particularly when a human fetus or a newborn infant is infected. In this instance, the infection is the result of a spread of the acquired disease which may occur in the mother in the last six months of pregnancy. Although the infection of adults can be dangerous and fatalities have been reported, the danger to the nervous system, eyes and other structures of the newborn infant can be devastating—blindness, brain damage and mental deficiency, particularly as the result of an obstruction to the flow of circulating cerebrospinal fluid within the brain.This report covers a number of differing features of the disease which have been described separately by other authors in specialty journals and in the foreign literature. If present, these signs should suggest toxoplasmosis, particularly in pregnancy, in the newborn infant and in still-born infants.Early diagnosis is of paramount interest in view of the poor response which may be obtained in the treatment of subacute and chronic phases of the illness. Difficulties in diagnosis stem from the manifestations of toxoplasmosis which closely resemble the symptoms of other infectious diseases.The clinical laboratory diagnosis is made by the isolation of the organism or by the demonstration of immune protein in the patient''s serum.     

Human cytomegalovirus-specific CD4+-T-cell cytokine response induces fractalkine in endothelial cells

Cytomegalovirus (CMV) infection has been linked to inflammation-related disease processes in the human host, including vascular diseases and chronic transplant rejection. The mechanisms through which CMV affects the pathogenesis of these diseases are for the most part unknown. To study the contributing role of the host immune response to CMV in these chronic inflammatory processes, we examined endothelial cell interactions with peripheral blood mononuclear cells (PBMC). Endothelial cultures were monitored for levels of fractalkine induction as a marker for initiating the host inflammatory response. Our results demonstrate that in the presence of CMV antigen PBMC from normal healthy CMV-seropositive donors produce soluble factors that induce fractalkine in endothelial cells. This was not observed in parallel assays with PBMC from seronegative donors. Examination of subset populations within the PBMC further revealed that CMV antigen-stimulated CD4(+) T cells were the source of the factors, gamma interferon and tumor necrosis factor alpha, driving fractalkine induction. Direct contact between CD4(+) cells and the endothelial monolayers is required for this fractalkine induction, where the endothelial cells appear to provide antigen presentation functions. These findings indicate that CMV may represent one member of a class of persistent pathogens where the antigen-specific T-cell response can result in the induction of fractalkine, leading to chronic inflammation and endothelial cell injury.