Diagnosis of Trichomonas vaginalis infection: The sensitivities and specificities of microscopy, culture and PCR assay.

OBJECTIVES: The aim of this study was to compare wet mount-, Giemsa stain-, acridine orange fluorescent stain-, cultivation- and polymerase chain reaction (PCR)-based approaches to establish which method or combination of methods was most effective in the laboratory diagnosis of trichomoniasis. STUDY DESIGN: Out of 200 investigated patients with various gynecological complaints, Trichomonas vaginalis infection was detected in 27 (13.5%) by any of methods investigated. Among women with trichomonads, a typical clinical finding was presented in only nine. For analysis of sensitivity and specificity of the methods used, the receiver operating characteristic (ROC) curve concept with culture as a gold standard was applied. RESULTS: Infection was diagnosed by wet mount in 14 (7.0%) women, by Giemsa stain in 11 (5.5%) and by acridine orange stain in 16 (8.0%) women. In 21 (10.5%) women, it was diagnosed by culture in Diamond's medium, and in 22 (11.0%) by PCR. For the initial diagnosis of trichomoniasis, wet preparation is the test that is widely available in most STD clinics, but its sensitivity is poor (66.67%). Giemsa stain shows a low sensitivity of 52.38%. Acridine orange shows reasonable sensitivity and specificity of 71.43% and 99.44%, respectively. The sensitivity and specificity of PCR (80.95% and 97.21%) did not exceed that of culture. CONCLUSION: With regard to the fact that trichomoniasis can have an atypical or even asymptomatic course, in order to accurately diagnose this disease, microbiological investigation is necessary. Comparison of different methods showed that at least two techniques, such as culture and acridine orange staining, have the potential for better diagnosis of T. vaginalis infection. PCR detection of infection has been demonstrated to be highly specific and sensitive, but its availability and cost effectiveness are in question. PCR could provide an alternative for laboratory diagnosis of trichomoniasis by culture.

[Antifungal drug resistance: mechanisms of resistance, freqeuncy, prevention and control of resistance].

Fungi are important causes of human infections, especially systemic mycoses. Pathogenic fungi have many complex mechanisms of resistance to antifungal drugs. In this article, information about the cellular, genetic and clinical factors contributing to antifungal-drug resistance, and their diagnostic and epidemiologic characteristics are reviewed. Understanding the mechanisms of resistance should assist in developing better detection and preventive strategies. The emergence of acquired antifungal resistance, especially in immunocompromised hosts, has necessitated routine antifungal susceptibility testing. Initial antifungal screening of clinical isolates by the disk-diffusion method would be followed by confirmation of resistant strains by the broth dilution method. Also, strategies to avoid and suppress the antifungal resistance are discussed. There are several strategies to overcome antifungal resistance, including increased antifungal-dose intensity, immunomodulation, combined antifungal therapy and new antifungals.

Correlation between clinical symptoms and diagnosis of trichomoniasis in women.

The aim of this study was to investigate correlation between clinical symptoms and diagnosis of trichomoniasis in women. 200 women were included in the study. Swabs were taken from all patients from the posterior vaginal fornix. Each sample was examined using the following five methods: wet mount, Giemsa stain, acridine orange fluorescence stain, cultivation in Diamond medium and PCR method. Trichomoniasis was diagnosed in 27 women using any of the applied methods and 33.3% presented with typical frothy yellow-green discharge, characteristic for tichomoniasis and yellowish discharge characteristic for the third group of vaginal discharge. White discharge, characteristic for Candida infection, was found in 18.5% of patients with diagnosed trichomoniasis. Finally, 14.8% of positive patients had a normal discharge. Based on the results of our study we came to the conclusion that microbiological investigations are necessary for accurate diagnosis of trichomoniasis, as well as for revealing asymptomatic infections, in order to prevent spreading of this relatively common disease.

[The role of parasites and fungi in secondary infertility]. / Uloga parazita i gljiva u nastanku sekundarnog steriliteta.

INTRODUCTION: Parasite-host relationships can cause diminished or absent ability to conceive, ectopic pregnancy or pregnancy with undesired course. LITERATURE REVIEW: There are reports that some protozoa, helminths and fungi may impair women's reproductive capacity, causing deformities of genital tract, so that conception is impossible, or, if it does occur, normal implantation and development of placenta are impossible. Schistosoma haematobium may cause vulvar papule, swelling, tumors, irregular vaginal hemorrhage, tubular infertility and ectopic pregnancies. Patients with cirrhosis caused by schistosomas have gonadal dysfunction and schistosomiasis itself can lead to tubular infertility. Some authors found microfilaria of Mansonella perstans in follicular aspirates in patients with tubular adhesions. Chronic Entamoeba histolytica infection can cause pelvic pain and dyspareunia in some patients. Although Trichomonas vaginalis is a common cause of tubal inflammation, this protozoa affects semen quality and leads to secondary infertility. Soluble parasite extract of T. vaginalis can lead to impaired motility of 50% spermatozoa in vitro and affects semen quality by increased viscosity and amount of debris, or damage spermatozoid membrane. In enterobiosis, presence of adult worms and eggs in fallopian tube, can be followed by chronic salpingitis and tubal occlusion. Also in ascariosis, presence of adult forms and eggs can lead to acute colpitis. chronic endometritis, salpingitis or ovarian abscess. The consequence of fungal infections, such as colpitis and endometritis, caused by Candida albicans, may be infertility. Also, according to some reports, C. albicans leads to decreased spermatozoan motility. CONCLUSION: Hence parasites and fungi can cause infertility, we recommend examination of both partners in treatment of infertility.

[Human babesiosis--recent discoveries]. / Humana babezioza--nova saznanja.

INTRODUCTION: Babesiosis is caused by intraerythrocytic parasites of the genus Babesia, which is a common animal infection worldwide. This protozoa requires both a competent vertebrate and a nonvertebrate host (Ixodes sp. etc.) to maintain the transmission cycle. HUMAN BABESIOSIS: Human babesiosis is predominantly caused by Babesia microti (rodent-borne piroplasm, an emerging zoonosis in humans in North America) and by Babesia divergens (bovine pathogen, in Europe). Occasionally, infection in America is caused also by a newly recognized species, so-called WA1 piroplasm. The spectrum of human babesiosis in the USA is broad, and ranges from an apparently silent infection to a fulminant. In Europe, babesiosis is considerably rarer, but more lethal (42% mortality rate in Europe and 5% in the USA, for clinically apparent infections) and mostly in splenectomized patients. Various determinants are involved in the severity of infection, such as age, immunocompetence and coinfection with other pathogens (Borrelia burgdorferi). B. microti antigens can trigger specific activation of T-cells and the infection can be effectively controlled by a Th1-dominant CD4+ T-cell response. The diagnosis of babesiosis should include examination of blood smears stained by Giemsa, as well as serologic evaluation with indirect immunofluorescent antibody tests and possibly PCR. The treatment of babesiosis depends on severity of cases; if it is mild it resolves spontaneously, whereas very severe cases with B. divergens require prompt treatment that includes erythrocyte exchange transfuision along with intravenous clindamycin and oral quinine to arrest hemolysis and prevent renalfailure. This paper offers an overview of recent developments in the investigation of Babesia sp. and babesiosis.

[Characteristics of the immune response in protozoan infections]. / Karakteristike imunskog odgovora u toku infekcije protozoama.

INTRODUCTION: When protozoa enter the blood stream or tissues they can often survive and replicate because they adapt to the resisting natural host defenses. The interaction of immune system with infectious organisms is a dynamic interplay of host mechanisms aimed at eliminating infections and microbial strategies designed to permit survival in the face of powerful effector mechanisms. Protozoa cause chronic and persistent infections, because natural immunity against them is weak and because protozoa have evolved multiple mechanisms for evading and resisting specific immunity. NATURAL AND SPECIFIC IMMUNE RESPONSE TO PROTOZOA: Different protozoa vary greatly in their structural and biochemical properties and stimulate distinct patterns of immune responses and have evolved unique mechanisms for evading specific immunity. Protozoa activate quite distinct specific immune responses, which are different from the responses to fungi, bacteria and viruses. Protozoa may be phagocytozed by macrophages, but many are resistant to phagocytic killing and may even replicate within macrophages. T. brucei gambiense is the best example of protozoa which can induce humoral immune response because of its extra-cellular location. In Leishmania sp. infections, cellular defense mechanisms depend upon CD4+ T-lymphocytes and activate macrophages as effector cells that are regulated by cytokines of Th1 subset. Plasmodium sp. is a protozoa which show the diversity of defence mechanisms which can be cellular or humoral, depending on Ag and protozoa's location. IMMUNE EVASION MECHANISMS OF PROTOZOA: Different protozoa have developed remarkably effective ways of resisting specific immunity: a) anatomic sequestration is commonly observed with protozoa Plasmodium and T. gondii; b) some protozoa can become resistant to immune effector mechanisms: Trypanosoma, Leishmania and T. gondii; c) some protozoa have developed effective mechanisms for varying their surface antigens: Plasmodium and Trypanosoma; d) some protozoa shed their antigen coats, either spontaneously or after binding with specific antibodies: E. histolytica; e) some protozoa alter host immune response by nonspecific and generalized immunosuppression (abnormalities in cytokine production, deficient T cell activation): Trypanosoma, Leishmania, Toxoplasma, Entamoeba. CONCLUSION: Protozoa activate numerous, different immune mechanisms in human body. Evolution, progression and outcome of diseases depend upon these mechanisms. Resent progresses in research have defined and selected Ag as candidates for new vaccines. Better definitions regarding the role of cytokines in protozoan infections will facilitate rational development of cytokines and cytokine antagonists and their use as immunotherapeutic agents.

[First case of Malassezia globosa isolation in Serbia]. / Prvi slucaj isolacije Malassezia globosa kod nas.

Today is known that genus Malassezia includes seven species: M. furfur, M. sympodialis, M. obtusa, M. globosa, M. restricta, M. sloofflae and M. pachydermatis, but role of each of the species in the pathogenesis of disease has not been elucidated yet, so further laboratory isolation and identification are necessary. We report the first case of isolation of Malassezia globosa in Serbia (Belgrade), in a patient suffering from Pityriasis versicolor. Identification of M. globosa was based on macroscopic, microscopic and biochemical characteristics. Isolation was done on Leeming and Notman medium and on mDixona agar, at 350C, during 7 days in aerobic conditions. Also the yeast's biochemical phenotype was determined as catalase (+), lipase (+), esculin degradation (-), Tween (20, 40, 60 and 80) assimilation (-). M. globosa is a lipophilic yeast of the genus Malassezia and the common member of the skin flora. In concordance with some predisponing factors M. globosa is implicated in the pathogenesis of several skin diseases (pityriasis versicolor, malassezia foliculitis, seborheic dermatitis and some forms of atopic dermatitis). In immunocompromised patients and neonates this yeast can even cause fatal systemic infections. Because the role of Malassezia spp. In pathogenesis of skin disease is not still determined, we suggest laboratory diagnosis and identification of these species as a routine diagnostic procedure.