Transcript Document

MYCOLOGY
（真菌学）
The fungi are eukaryotic organisms真核细胞型
growing as a mass of branching, interlacing 交错的
filaments known as mycelium菌丝体. Among the
many thousands of fungi known, only about 300
can cause diseases in humans and animals.
plant
Bacteria
※Comparison of fungi and bacteria
feature
fungi
bacteria
diameter
4um
1um
nucleus
Eukaryotic真核的
Prokaryotic原核的
cytoplasm
Mitochondria and Golgi
apparatus , endoplasmic
reticulum present
Mitochondria and
endoplasmic reticulum
absent
Cell membrane
Sterols present有胆固醇
Sterols absent有胆固醇
Cell wall
Chitin几丁质
Peptidoglycan, phospholipid
spores
Sexual and asexual spores for
reproduction
spores for survival, not for
reproduction
metabolism
Require organic carbon; no
obligate anaerobes专性厌氧
May do not require organic
carbon; many obligate
anaerobes
Structure of fungi
※A. Morphology and Structure
Unicellular fungi ( yeast 酵母菌)
Multicellular fungi (filamentous fungus 丝状菌mold霉菌)
Hypha 菌丝: mycelium菌丝体
( vegetative营养, aerial气中 or reproductive生殖)
Spores 孢子: 繁殖结构 sexual spore and asexual spore
a) Conidium （分生孢子） :
macroconidium, microconidium.
b) Thallospore （叶状孢子） :
blastospore芽生, chlamydospore厚膜, arthrospore关节
c) Sporangiospore (孢子囊孢子）：
Unicellular fungi
Multicellular fungi
Hypha
spore
链霉菌菌丝
小分生孢子
大分生孢子
two main groups:
※yeasts and molds
Yeasts : reproduce by asexual budding 出芽
Molds :
a. Hypha
b. Spore
asexual cell division or
sexual reproduction
Dimorphic fungi 双相性:
Several medical important fungi are dimorphic fungi.
They are capable of converting from a yeast or yeastlike form to a filamentous form and vice versa 反之亦
然， usually exist in the yeast of yeast-like form in a
mammalian body and as the filamentous form in the
environment or general media.
B. ※Culture
※ Sabouraud culture medium
沙保培养基
optimal pH 4-6
optimal temperature 22-28 ℃ some
deep pathogenic fungi need 37 ℃
Aerobic需氧
※ types of colonies – yeast
filamentous
Unicellular fungi
(smooth, soft, compact 紧凑)
Unicellular fungi
Multicellular fungi
( floc絮状, villiform绒毛状, dusty飞扬 )
Multicellular fungi
Resistance
Resistant to dry, sunlight, UV
light and many chemicals
Sensitive to wet heat
D. PATHOGENESIS致病性
Pathogenic fungal infection
（浅部感染和深部感染）
Opportunistic pathogenic
fungal infection
Fungal allergic diseases
Mycotoxicosis真菌性中毒
Mycotoxin and tumor
真菌毒素与肿瘤
1. Pathogenic fungal
infection
For example, dermatophytes皮肤癣菌
( colonizers of the skin, hair, and nails )
elaborate the enzyme keratinase角蛋白酶,
which hydrolyzes the structural protein
keratin.
2. Opportunistic
fungal infection
Some circumstance情况 that lead to infection
the use of broadspectrum antibacterial drugs
Weakness of the host by the use of therapeutic
measures (e.g. x-ray irradiation, steroids, and other
immunosuppressive抑制 drugs)
alteration of the host's immune system (e.g.
uncontrolled diabetes mellitus糖尿病, suppression
such as that cause by AIDS).
3. Fungal Allergies
Throughout life, the respiratory tract is exposed to
airborne空气传播的conidia分生孢子and spores of
many saprophytic腐生的fungi.
These particles often possess potent 有效的 surface
antigens capable of stimulating and eliciting引起
strong allergic reactions.
In some cases both infection and allergy may occur
simultaneously同时地. Depending on the site of
deposition沉积作用 of the allergen, a patient may
exhibit rhinitis鼻炎, bronchial asthma, alveolitis齿槽炎,
or generalized无显著特点的 pneumonitis. Atopic 遗传
性过敏症的persons are more susceptible .
4. Mycotoxicosis
Many fungi produce poisonous substances
called mycotoxins that can cause acute or
chronic toxicosis and damage.
Mycotoxicosis may result from ingestion of
fungal-contaminated foods.
5. Mycotoxin and tumor
Aflatoxins黄曲霉毒素 produced by
Aspegillus flavus黄曲霉 have become
known as potent carcinogens致癌物质 .
E.Immunity
Nonspecific
immunity
Specific immunity
Nonspecific barriers to fungal infection must be
crossed, however, before specific immune responses
to fungi are elicited.
These primary barriers to fungal infection include
intact skin, naturally occurring long-chain
unsaturated fatty acids※, and competition with
normal bacterial flora.
In addition the mucous membranes are covered with
fluids containing antifungal substances. Furthermore,
many epithelial cells of the mucous membranes
contain cilia that actively remove microorganisms.
Both humoral and cell mediated immunity (CMI) are
important in control of fungal infections, but CMI※
appears to be more important since patients with defects缺
陷 in CMI usually suffer more severe fungal infections
than do persons with depressed降低的 humoral immunity.
The cell-mediated immune response is protective; its
suppression can lead to reactivation and dissemination再
发和扩散 of asymptomatic fungal infections and to disease
caused by opportunistic fungi. Circulating IgG and IgM
are produced in response to fungal infection, but their role
in protection from disease is uncertain.
F . Microbiological
diagnosis
Specimens
Direct smear
Isolation and cultivation
Serological tests
G. PREVENTION AND
TREATMENT
Prevention includes avoidance of environments and
conditions conducive to fungal growth.
The drugs used to treat bacterial diseases have no
effect on fungal diseases. The effective drugs exploit
作用于 the presence of ergosterol麦角固醇 in
fungal cell membranes. These drugs, i.e.,
amphotericin B and the various azoles.
总
结
真菌属于哪类微生物？与细菌有什么区别？
真菌的形态结构特点？
真菌的培养特点？
真菌致病作用有哪几方面？
真菌感染后以何种免疫性为主？
MAIN PATHOGENIC FUNGI
Superficial 表面真菌病
cutaneous皮肤真菌病
subcutaneous mycoses
皮下组织真菌病
systemic infections
系统真菌病
A．Superficial Mycoses
表面真菌病
Malassezia furfur （秕糠马拉癣菌）
◆Pityriasis versicolor花斑癣是由粃糠马拉癣菌感
染皮肤角质层引起的慢性感染
◆ Discrete, serpentine, hyper- or hypopigmented
maculae occur on the skin皮肤上出现分散、蜿
蜒、色素加深或减低的斑点
B．Cutaneous Mycoses-----Dermatophytes
皮肤真菌病
superficial keratinized tissue角化组织
infection,The most important are
dermatophytes （皮肤癣菌）, classified into
3 genera:
Trichophyton （毛癣菌）
Epidermophyton （表皮癣菌）
Microsprum （小孢子癣菌）
Invade only skin, hair, and nails.
1. Distinctive Properties:
unable to grow at 37℃ or in the presence
of serum .
have developed keratinases角蛋白酶 ,
elastases弹性蛋白酶 , and other enzymes
that enable them to be quite host-specific
宿主特异性 .
Dermatophytes are identified by their
colonial appearance菌落外形 and
microscopic morphology after growth for 2
weeks at 25℃ on Sabouraud's agar
2. Pathogenesis:
infected persons by direct contact.
Microsporum 小孢子癣菌属 is also spread from
animals.
A single species →
more than one type of infection
A single infection →
more than one species
clinical manifestation
They can causes tinea pedis足癣
(Athlete's Foot), feet; tinea unguium
甲癣 , nails; tinea corporis体癣 ,
body; tinea cruris股癣, groin; tinea
manus手癣, hands; tinea capitis头癣,
scalp hair; and tinea barbae须癣,
beard hair.
3.Diagnosis:
Scrapings被刮削下的碎屑of skin or nail
→10% KOH on a glass slide show
hyphae菌丝 under microscopy.
Cultures on Sabouraud's agar at room
temperature develop typical hyphae
and conidia分生孢子
C．Subcutaneous Mycoses
皮下组织真菌病
Chromomycosis广色霉菌病
(caused by several species of
black molds; Fonsecaea edrosoi,
Cladosporium carrionii,
Phialophora verrua have been
isolated most frequently).
D. Systemic mycoses
系统真菌病
（1）pathogenic fungi
→ ※Cryptococcus
neoformans 新生隐球菌
Oval 椭圆的, budding
yeast surrounded by a
wide ※ polysaccharide
capsule
a．Distinctive
Properties:
its ability to grow at 37 ℃
the production of phenol oxidase苯酚氧化酶
b．Pathogenesis:
Infection follows inhalation吸入 of the cell,
which , in nature , are thought to be small , allowing the
organism to enter deep into the lung.
No human to human transmission
The commonest manifestation is a subacute or chronic
form of meningitis （隐球菌性脑膜炎 ）
C. neoformans can be isolated in large numbers from
pigeon droppings粪 in the environment
c．Diagnosis:
Tests for capsular antigen can be performed测试
on cerebrospinal fluid and serum.
The latex slide agglutination test检测隐球菌抗原的
乳胶凝集试验
cerebrospinal fluid mixed with a drop of
※India ink, the yeast cell can be seen
microscopically to be surrounded by a wide,
unstained capsule.
脊髓液与一滴印度墨汁混和后
在显微镜下可见厚的、不着色
的荚膜
(2) Opportunistic Mycoses→
※Candida（假丝酵母菌）
Others:
Aspergillus（曲霉）
Mucor（毛霉）
Pneumocystis carinii(卡氏肺孢菌）
A. Candida Albicans
（白色念珠菌）
Candida albicans（白假丝酵母菌） is a
yeast causing candidiasis （念珠菌病）or
※"thrush" （鹅口疮）in humans.
※C. albicans is part of the normal flora of
the vagina and gastrointestinal tract
As a superficial mycoses, candidiasis
typically infects the mouth or vagina.
Antibiotic treatment can also alter the
normal bacterial flora allowing C. albicans
to flourish活跃.
1．Distinctive Properties:
oval, budding yeast
cells. also form
※pseudohyphae .
On nutritionally deficient
media ， produces large,
spherical※chlamydospores
厚膜孢子 .
2．Pathogenesis:
a. Cutaneous and Mucosal Candidiasis:
1.Oral thrush鹅口疮 can occur on the tongue, lips唇, gums齿龈 ,
or palate上颚 . Yeast invasion of the vaginal阴道 mucosa leads to
vulvovaginitis外阴阴道炎 .
2.Other forms include invasion of the skin.
occurs in moist, warm parts of the body such as the
axillae腋下 , groin腹股沟 . The infected areas
become red and moist and may
develop vesicles泡 .
3. onychomycosis甲癣 .
口腔白念病
白念甲沟炎
红斑型白念病
白念食管炎
b. Systemic Candidiasis:
1. caused by indwelling catheters留置导管 ,
surgery, intravenous drug abuse 滥用, damage
to the skin or gastrointestinal tract.
2.Patients with compromised phagocytic
defenses细胞免疫缺陷 may develop occult
lesions隐匿损害 anywhere, especially the
kidney, skin, eye, heart, and meninges脑膜.
c. Chronic Mucocutaneous Candidiasis:
Most forms have onset发作 in early
childhood, are associated with cellular
immunodeficiency and
endocrinopathies内分泌病 , and result
in chronic superficial disfiguring损坏
infections of any or all areas of skin or
mucosa.
3. immunity:
Cell-mediated immune responses,
especially CD4 cells, are important in
controlling mucocutaneous粘膜与皮肤
candidiasis, and the neutrophil 嗜中性
粒细胞 is probably crucial至关紧要的for
resistance to systemic candidiasis.
4. Diagnosis:
Sputum
Scrapings from lesions
Blood smears
Vaginal discharge
5. Prevention and
Urine
Treatment:
Feces
标本: 拭子和表皮病损刮
Amphotericin B
取物、血液、脊髓液、组
Nystatin制霉菌素
织活检、尿液和渗出物等
Ketoconazole
苯并二氢呋喃酮
Fluconazole氟康唑
B. Other opportunistic
mycoses (自学 )
1. Aspergillus曲霉
2. Mucor毛霉
3. Pneumocystis carinii卡氏肺孢菌
总
结
致病性真菌可引起哪些类型的疾病？
引起系统性真菌病主要有什么菌？
新型隐球菌的染色特点？培养特点？
新型隐球菌引起的疾病？
白色念珠菌的结构特点？
白色念珠菌引起的疾病？