主要致病性真菌课件.ppt

1、主要致病性真菌浅部真菌感染（致病性真菌感染和条件致病性真菌感染）深部真菌感染（致病性真菌感染和条件致病性真菌感染）Pityriasis versicolor showing hyperpigmented lesions in a Caucasian and hyphopigmented lesions in an Australian AborigineCulture of Malassezia furfur on Dixons agar(contains glycerol mono-oleate)Piedraia hortae forms a hard superficial pigment

2、ed nodule around the hair shaft(在毛干上形成硬的黑色结节，如沙粒状)一种皮肤癣菌可在不同部位引起病变相同部位的病变也可由不同的皮肤癣菌引起Tinea pedis caused by T.rubrum.Sub-clinical infection(left)showing mild maceration under the little toe and more severe infection(right)showing extensive maceration of all toe web spaces Tinea is transmitted via the

3、 feet by desquamated skin scales in substrates like carpet and matting.nusually caused by Trichophyton spcaused by M.canis,following contact with infectious kittensTinea favosa发内孢子发内孢子Tinea alba发外孢子发外孢子脓癣脓癣念珠菌性间擦念珠菌性间擦疹疹好发部位：腋窝、乳房下、好发部位：腋窝、乳房下、腹股沟、会阴，多见于婴儿腹股沟、会阴，多见于婴儿及肥胖者。及肥胖者。Interdigital candidias

4、is Candidia onychomycosis and paronychia Oral thrush此菌可经微小损伤侵入皮肤，然后沿淋巴管分布，引此菌可经微小损伤侵入皮肤，然后沿淋巴管分布，引起亚急性或慢性肉芽肿，使淋巴管形成链状硬结，称起亚急性或慢性肉芽肿，使淋巴管形成链状硬结，称为孢子丝菌下疳。为孢子丝菌下疳。Chronic verrucous chromoblastomycosis of the hand due to Cladophialophora carrionii nAre uncommon,In infected tissues,C.immitis appears as a

5、 mixture of endospores and spherules.ConidiaSpherules1.Ethnicity:Filipinos,African Americans,Native Americans at higher risk2.Age:Extremes more susceptible3.Sex:Males more susceptible4.Pregnancy:3rd trimester5.ImmunosuppressionF.Diagnosis1.Exam:Suppurative or granulomatous inflammation2.Histopatholo

6、gy:spherules or endospores seen in sputum,exudates or tissue3.Culture:danger,highly infectious!4.Serology:Complement fixation assay(in cerebrospinal fluid),particle agglutination assay G.Treatment1.Amphotericin B followed by an azoleE.Risk FactorsCaused by the dimorphic fungus Histoplasma capsulatum

7、Tuberculated macroconidia,grown at 25CIntracellular yeast at 37CHistoplasmosis is characterized by intracellular growth of the pathogen in macrophages and a granulomatous reaction in tissue.These granulomatous foci may reactivate and cause dissemination of fungi to other tissues.B.SpreadC.Immune Res

8、ponse1.Cell-mediated responses are of primary importance2.Activated macrophage can kill yeast cellsD.Evasion of Defenses1.Survival in macrophages elevates pH of phagosomes2.Yeast cells absorb iron(siderophore)and calcium from host3.Alteration of cell surface 1.Direct histology and culture of blood o

9、r bone marrow2.Serological testing for antibody and histoplama antigen in blood and urine.E.DiagnosisD.Damage1.Lung-bronchial obstruction and inflammatory sequelae2.Disseminated histoplasmosis-fulminant disease that may result in toxic shock3.CNS-fatal if untreated.F.TreatmentAmphotericin still main

10、stay of therapy vs.disseminated and severe pulmonary histoplasmosis.Ketoconasole or itraconasole is effective as therapy for self-limited disease(used in AIDS).Ocular HistoplasmosisA small fraction of individuals form scar tissue in the retina many years after the original histoplasmosis infection.L

11、ive organisms cannot be recovered from these specimens.The scarring can obscure the macula and lead to loss of central vision.The first signs are small“histo spots”.Advanced disease is treated with laser photocoagulation to limit the proliferation of blood vessels.Blastomyces dermatitidis Dimorphic

12、organism originates in the soil and infection ensues by inhalation of spores.Converts to yeast in animal hosts or at 37o in vitro.Immune response1.Alveolar macrophage provide a first line of defense.2.T-cell stimulated PMNs kill Blastomyces cells by oxidative mechanisms.3.Conidia are more sensitive

13、to killing by PMNs because yeast are too big.4.TH-1 response is of primary importanceTreatmentnOpportunistic mycoses are fungal infections that do not normally cause disease in healthy people,but do cause disease in people with weakened immune defenses(immunocompromised people).Weakened immune funct

14、ion may occur due to inherited immunodeficiency diseases,drugs that suppress the immune system(cancer chemotherapy,corticosteroids,drugs to prevent organ transplant rejection),radiation therapy,infections(e.g.,HIV),cancer,diabetes,advanced age and malnutrition.nThe most common infections are:形态：圆形或卵

15、圆形单细胞真菌，革兰阳性繁殖：出芽繁殖，形成假菌丝，在组织易形成芽生孢子培养：普通琼脂、血琼脂与沙保培养基 需氧。室温或 37甚至42生长良好 菌落灰白色或奶油色，表面光滑，带有浓厚的酵母气味。有大量向下生长的营养假菌丝，呈类酵母型。在玉米粉培养基上可长出厚膜孢子假菌丝和厚膜孢子圆形，有肥厚荚膜（一般厚度是直径的两倍）染色：一般染色法不易着色，墨汁负染，胞内有较大的反光颗粒。出芽繁殖，不形成假菌丝（酵母型菌落）培养特性：沙保或血琼脂培养基，2537生化特性：分解尿素荚膜多糖抗原：AD 和AD 5个血清型，我国约70%属A型曲霉Aspergillus 烟曲霉 支气管哮喘或肺部感染 毛霉Mucor

16、 腐生菌 脑、肺、胃肠道卡氏肺孢菌Pneumocystis carinii 免疫缺陷病人 肺炎Aspergillus flavusAspergillus nigerAspergillus fumigatus卡氏肺孢菌Pneumocystis carinii 生物学性状单细胞型，兼具原虫及酵母菌的特点，其发育过程如下：孢子小滋养体大滋养体（二分裂、出芽或接合生殖）囊前期孢子囊囊内减数分裂形成孢子成熟孢子囊内含8个孢子致病性艾滋病患者最常见的并发症和主要的致死原因微生物学检查采集痰液，染色镜检，若发现滋养体或孢子囊可确诊防治本菌对多种抗真菌药物不敏感，用药首选复方新诺明X-ray of Pneumocystis jirovecii pneumoniaThere is increased opacification(whiteness)in the lower lungs on both sides,characteristic of Pneumocystis pneumonia