过氧化氢对白色念珠菌DNA破坏的研究

本文用热变性温度法研究一定浓度 H_2O_2对 C.albicans DNA 破坏作用。结果表明,经6%和10%H_2O_2处理后,C.albicans DNA G c Mol%(分别为28.1±0.82和14.4±1.51)显著低于对照 DNA G C Mol%(85.9±0.62),并推断 H_2O_2可能作用于 C.albicans DNA 碱基以及其间的氢键上;DNA 电泳图谱发现,经3%和6%H_2O_2处理的 C.albicans DNA 电泳带明显不同于对照,提示 H_2O_2更易造成 C.albicans DNA 核苷酸链的降解或断裂.H_2O_2对 C.albicans DNA 的破坏,增强了其杀菌作用。     

Oral manifestation of chronic mucocutaneous candidiasis: seven case reports

BACKGROUND: Chronic mucocutaneous candidiasis (CMC) is a rare disorder characterized by persistent or recurrent candidal infections of the skin, nails and mucous membranes or by a variable combination of endocrine failure as well as immunodeficiency. Oral clinicopathological features of CMC have seldom been described in detail. METHODS: Seven patients with CMC were reported in the study. The clinical and histological findings, etiological Candida species, immunological evaluation, and therapeutic pattern of oral lesions, were analyzed. RESULTS: Long-standing whitish hyperplastic and nodule-like lesions with exaggerated deep fissure were the typical and characteristic oral manifestations presented by all patients. The tongue was the most common site affected. Histologically, no obvious distinction was found between CMC and other forms of candidal infection. Abnormal proportions of T-lymphocyte subsets and positive titers of autoantibody were observed in three subjects (42.9%) and one patient (14.3%) respectively. Meanwhile, four subjects (57.1%) showed decreased albumin and increased globulin, three cases (42.9%) had high levels of ESR. But no iron deficiency was found. Candida albicans was the microorganism isolated from these patients. CONCLUSIONS: Multiple and widespread candidal infectious lesions can be observed on the oral cavity of CMC patients. Hyperplastic and nodule-like lesion with irremovable whitish patches and deep fissure are the most common oral manifestations of these patients. Dentists, otolaryngologists and pediatricians should be familiar with the clinical appearances of CMC to make an accurate diagnosis. Potential systemic disorders should be concerned to avoid the reoccurrence of oral candidiasis.     

Ultrastructure of experimental candidial lesions in the rabbit esophagus

Although the esophagus is the most frequent site ofCandida infections in the gastrointestinal tract, and many clinical studies about it have been reported, little attention has been directed toward experimental candidiasis of the esophagus, especially with regard to its ultrastructure. Using transmission electron microscopy, this study was performed to clarify the ultrastructure of experimental lesions, obtained from five New Zealand white male rabbits which were given a suspension ofCandida albicans cells (10⁷/ml) for 13 days. The results showed that the lesions consisted of exfoliating, squamous epithelial cells with mycelial elements ofCandida albicans cells penetrating through them, and that a widened intercellular space between individual cells in the area of candidial invasion seems to be a characteristic finding of candidial infection. A part of this study was presented at the 25th Annual Meeting of the Clinical Electron Microscopy Society of Japan, Matsumoto, September 28–30, 1993.     

Role of thermal trauma in experimental oral mucosal Candida infections in rats

A model of candidosis in experimental rats was used to study the role of trauma in the aetiology of oral mucosal infections caused by Candida albicans. Standardised thermal trauma was delivered to the dorsum of the tongue of Sprague-Dawley rats and experimental candidosis was induced. Histologically. the site of trauma was invaded by hyphae earlier and more extensively than in control animals, leading to the conclusion that trauma facilitated the establishment of the C. alhicana infections.     

正常儿童口腔中白色念珠菌的分布及基因分组

目的 研究以白色念珠菌为代表的念珠菌，以及白色念珠菌基因分组在不同年龄段儿童口腔中的分布情况。方法 4组不同年龄儿童和1组成人作为研究对象，粘膜拭子法取样，CHROMagar Candida鉴定培养基分离鉴定，PCR方法一组引物确认白色念珠菌，一组引物基因分组。结果 不同年龄组儿童口腔中念珠菌的检出率有所不同，除健康青年外，白色念珠菌在检出的念珠菌中均占多数。白色念珠菌3种基因分组的分布也存在差异，以A组为主。结论 不同年龄阶段健康儿童口腔中，A组白色念珠菌组占主导地位。     

Mannose binding lectin and C3 act as recognition molecules for infectious agents in the vagina

In our study we examined the early complement components in patients with bacterial vaginosis (BV), vulvovaginal candidiasis (VVC) and in healthy controls. The levels of C1q, mannose-binding lectin (MBL) and C3 were measured by ELISA in the cervicovaginal lavage (CVL) from gynaecological patients and controls. No significant differences were observed in the levels of these proteins in the three study groups. Immunofluorescence analysis of the clue cells and Candida hyphae from BV and VVC patients for surface-bound complement components showed the presence of C3, while C1q was undetectable. MBL was revealed on clue cells but not on Candida. Binding of MBL to Candida, grown or cytocentrifuged from the CVL of VVC patients, was found to be pH dependent and occurred between pH 4.5 and pH 5.5. In conclusion, we demonstrated that MBL and C3 present in the vaginal cavity act as recognition molecules for infectious agents that colonize the cervicovaginal mucosa. Our finding that MBL, but not C1q, binds to bacteria and fungi in vagina suggests that the lectin and classical pathways of complement activation may play a different role in immune defence in the female genital tract.     

Detection of Brucella melitensis by the BacT/Alert automated system and Brucella broth culture

This study was conducted to evaluate the ability of the BacT/Alert automated blood culture system to detect Brucella spp. in comparison with traditional Brucella broth culture. Overall, 100 (50 bone marrow and 50 blood samples) paired cultures were obtained, and 59 were positive by at least one method. The Brucella broth culture method detected all 59 positive cultures (100%), and the BacT/Alert system detected 30 (50.8%) ( P  < 0.05). The mean detection times for B. melitensis were 4.5 days in the BacT/Alert system and 5 days in Brucella broth culture ( P  > 0.05). There is no significant difference between the two methods with respect to growth time of the microorganism, but Brucella broth culture is more sensitive than the BacT/Alert system.     

Candida and antibiotic-associated diarrhoea

The role of Candida in antibiotic-associated diarrhoea (AAD) has been controversial for many years. Since Candida exists physiologically in the gastrointestinal tract, the presence of small numbers of Candida organisms in stool has therefore been considered normal, and thus non-pathogenic. Increased Candida counts have been linked to the development of diarrhoea in antibiotic-treated patients. However, recent findings have not confirmed this. To date, there is no convincing evidence that Candida may cause AAD in adults.     

双重实时荧光定量PCR法鉴定克柔念珠菌和光滑念珠菌

目的 建立一种快速、灵敏、特异的鉴定克柔念珠菌和光滑念珠菌的双重实时荧光定量PCR方法.方法 以核糖体基因内转录间隔区Ⅱ(ITSⅡ)为靶目标,设计并合成分别针对克柔念珠菌、光滑念珠菌的种特异引物和探针.建立双重实时荧光定量PCR反应体系,并用该体系对呼吸道相关致病菌进行检测.鉴定结果与临床常规鉴定方法对照,评价其敏感度、特异度及重复性.结果 通过对100例样品的检测,结果显示该双重实时荧光定量PCR法检测标本的鉴定结果与常规鉴定方法的结果对照,特异度为100%,敏感度为100%;最小能检测到10个拷贝数的重组质粒;批内重复实验和批间重复实验结果均与常规鉴定方法结果相符.结论 双重荧光定量PCR法鉴定克柔念珠菌和光滑念珠菌,特异度和敏感度高,重复性好,且快速、简便,该方法将有助于念珠菌病的早期诊断和针对性治疗.     

Molecular characterisation of extended-spectrum β-lactamase-producing Escherichia coli and Klebsiella spp. isolates at a tertiary-care centre in Lebanon

The prevalence of bla _CTX-M, bla _TEM and bla _SHV genes among extended-spectrum β-lactamase (ESBL)-producing clinical isolates of Escherichia coli ( n  = 50) and Klebsiella spp. ( n  = 50) from Lebanon was 96%, 57% and 67%, and 40%, 82% and 84%, respectively. Genotyping revealed that the clonal diversity was unrelated to the presence of bla genes. Sequence analysis of 16 selected isolates identified the bla _CTX-M-15, bla _TEM-1, bla _OXA-1 and six bla _SHV genes, as well as the gene encoding the quinolone-modifying enzyme AAC(6')-Ib-cr. The genes encoding CTX-M-15 and AAC(6')-Ib-cr were carried on a 90-kb plasmid of the pC15-1a or pCTX-15 type, which transferred both ESBL production and quinolone resistance from donors to transconjugants.