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Reed Brooks Diagnostic Microbiology > Final Exam > Flashcards

Final Exam Flashcards

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Biology 101 flashcards
1
Q

Taxonomy of Viruses

What do these suffixes refer to?

  • virales
  • viridae
  • virinae
  • virus
A
  • virales: Orders
  • viridae: Family
  • virinae: subfamily
  • virus: genera
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2
Q

Initial classification of viruses is made by ______ and how many of each are of clinical importance?

A

nucleic acid composition

RNA-14 families
DNA-6 families

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3
Q

Types of viral diseases

A
  • Respiratory
  • Enteric
  • Exanthematous (skin eruptions)
  • hepatitis
  • persistent (latent)
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4
Q

Viruses are what type of pathogen?

A

obligate intracellular pathogen

cannot replicate outside of a host cell

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5
Q

What is tropism?

A

Viruses are host specific, meaning they have a limited number of hosts they can infect and survive in.

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6
Q

When are you considered contagious with a viral infection?

A

Varies

norovirus-from the time you display symptoms up yo 3 days after recovery

common cold-2-3 days after symptoms occur and lasts for a week

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7
Q

What is:

Antigenic Shift?

Antigenic Drift?

A

Antigenic Shift-infrequent major changes in the genetic structure of a virus (possibly incorporating host DNA into its viral genetic structure) creating a completely new virus

Antigenic Drift-minor changes in the genetic structure that occur during replication and this can occur all the time. The resulting virus is similar to the original with similar antigenic properties ( the immune system may still recognize it). Immunity can be lost over time due to the accumulation of the changes.

need for seasonal influenza vaccine

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8
Q

What is a virion?

It is measured in….

A

virus particle

nanometers

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9
Q

Viruses use ____ to replicate because they cannot _______.

A
  • host cell machinery

- self replicate

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10
Q

Structural components of a virion

A

Genetic material (DNA or RNA) capsid (made of capsomeres)
Possible:
envelope
glycoprotein spikes

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11
Q

What are capsomeres?

A

repeating structural subunits that make up the capsid

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12
Q

What is a capsid?

A

Protein coat that encloses the virus’s genetic material.

genome + capsid=nucleocapsid

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13
Q

What is a virion envelope and what is it prone to?

A

A lipid membrane that surrounds the capsid of certain viruses.

Prone to drying, thus transmission is via direct contact (prevent exposure to environment)

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14
Q

What are vision glycoprotein spikes?

A

attached projections on the surface of a virion that aid in stabilization and may have some enzymatic activities.

These projections can change, which also impairs a need for seasonal influenza vaccines.

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15
Q

Modes of viral transmission:

Which one is considered the most common route?

A
  • direct contact
  • injection with contaminated fluids or blood
  • organ transplantation
  • fecal-oral
  • respiratory (inhalation is the most common route)
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16
Q

Viral disease progression

A 
1-acquisition
2-attachment
3-penetration
4-uncoating
5-replication
6-macromolecular synthesis
7-assembly
8-release
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17
Q

Viral disease progression

Acquisition

A

Entry into the body

viruses can enter the body via inhalation, but cause infection elsewhere in the body

Spreads via the blood or lymphatics

Symptoms of disease-due to tissue damage and host immune response

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18
Q

Viral disease progression

Attachment

A

Recognition/binding to host cell receptors

Tropism-infect only certain tissues due to recognition of limited numbers of host cells

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19
Q

Viral disease progression

Penetration

A

Process of entering host cell

Mechanism(s)

  • fusion of viral envelope with host cell membrane
  • penetrating host cell membrane with tail
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20
Q

Viral disease progression

Uncoating

A

releasing viral genetic material into the host cell

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21
Q

Viral disease progression

Macromolecular synthesis

A

production of nucleic acids/protein polymers

mRNA encodes early and late proteins

Early proteins: nonstructural, usually enzymes

Late proteins: structural

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22
Q

Viral disease progression

Assembly

A

arrangement of structures

Virion becomes intact and is ready for release

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23
Q

Viral disease progression

Release

A

Via host cell lysis OR budding with cytoplasmic membranes

Influenza virus-hemadsorption

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24
Q

Common cells used for detection of viruses

These are examined periodically to look for:

A

human diploid fibroblasts, human epidermoid, primary monkey kidney

examined to observe cytopathic effects

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25
Q

Histologic detection of viruses

A

via H&E or special stains and identifying intracellular/intranuclear inclusions (cytopathological effects)

Examples: multinucleate cells, inclusion bodies

“owl eye inclusions” in lung pneumocyte-CMV

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26
Q

Viral detection methods

A 
Viral cell cultures
histology
serology
Ag detection via rapid tests
Electron microscopy
MALDI-TOF
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27
Q

Type of swab to use when collecting viral specimens and why?

A

Universal transport swabs by BD (transport media contains proteins to stabilize the viruses and antimicrobials to prevent growth of bacteria)

Calcium alginate swabs are NOT acceptable due to interface with PCR and fluorescent antibody testing

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28
Q

Viral cell cultures are inoculated with _____ to ______ uL of specimen

A

Viral cell cultures are inoculated with 200 to 400 uL of specimen

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29
Q

Processing viral specimens

A

Varies depending on the source, but can include:
setting up a cell culture
Direct detection

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30
Q

A viral specimen should be processed ______ upon receipt in lab.

A

Immediately

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31
Q

Viral specimen sources

A 
bronchial washes
rectal swabs/stool
vesicular lesions of skin
mucous membranes
CSF
blood
bone marrow
tisse
cervical swabs
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32
Q

The amount of viral infections/diseases has increased with the advent of:

A

improved medical technologies (organ transplantation, cancer care….both lead to immunosuppression

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33
Q

How does hemadsorption work to detect influenza in cell line cultures?

A

The virus manufactures glycoprotein hemagglutinins that get inserted into the host cell membrane, then later get incorporated into the virus during budding

In cell culture, adding RBCs will cause the RBC to adsorb to surface membrane of virally infected cells only and can be visualize microscopically.

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34
Q

Viral Pathogenesis:

Possible outcomes of viral infections

A 
Transient illness
chronic infection
laten infections
cancer
Death of host
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35
Q

Bunyaviruses

Genetic material:
Envelope?
Vector:
Important viruses within this family:

A 
Genetic material: 3 single strands of RNA
                 (**tripartite genome**)
Envelope? yes
Vector: mosquito
Important viruses within this family:
Arbovirus and Hentaviruses
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36
Q

Hentaviruses are _____, but are not ________.

Transmission?

A

Bunyaviruses, but are not Arboviruses

Transmission via inhalation of rodent excrement

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37
Q

Bunyaviruses infection/disease

Arboviruses

A

California encephalitis, (self-limiting)

LaCrosse viruses (asymptomatic to neuroinvasive)

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38
Q

Real-time PCR measures….

A

the amplified products in real-time rather than at the end of a series of cycles

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39
Q

Most common viral agent causes gastroenteritis in the U.S.

A

norovirus

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40
Q

Norovirus more commonly infects _____ whereas sapovirus more commonly infects ______.

A

Norovirus more commonly infects all ages whereas sapovirus more commonly infects infants and children

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41
Q

Calicivirus general: Norovirus

Linked to outbreaks of gastroenteritis:
Transmission:
Diagnostic testing:

A

Linked to outbreaks of gastroenteritis: on cruise ships, in nursing homes, schools

Transmission: contaminated water, person-to-person, airborne droplets of vomitus

Diagnostic testing: real-time PCR

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42
Q

Caliciviruses

Genetic material:
Major Genera:
Infections:

A

Genetic material: RNA
Major Genera: norovirus and savories
Infections: gastroenteritis

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43
Q

The term “arbo” virus refers to……

What families of viruses are part of this group?

A

arthropod borne viruses
(transmission via arthropod vectors)

Bunyaviridae, Togaviridae, Flaviviridae

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44
Q

Arenaviruses

1-Enveloped?
2-Genetic material:
3-Glycoprotein spikes:
4-Transmission:
5-Infections:
A 
1-yes
2-RNA
3-T-shaped
4-inhalation of aerosols from rodent/bat excretement
5-Lassa Fever

**Can cause fever, headache, possibly meningitis and hemorrhagic fever
80% are asymptomatic

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45
Q

Targets for antiviral drugs

A
  • Attachment (neutralizing Abs: HIV)
  • Penetration and Uncoating (Amantadine, rimantadine: Influenza A)
  • Transcription
  • Protein synthesis
  • DNA replication
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46
Q

Adenoviruses

1-Envelope?
2-Genetic material:
3-Infections:
4-Transmission:

A

1-No
2-Genetic material: dsDNA
3-resp. infections in children, gastroenteritis, keratoconjuntivitis
4-via aerosolized droplets or could be airborne

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47
Q

Coronaviruses

1-Transmission:
2-Genetic material:
3-Envelope?

A

1-via respiratory secretions and aerosals
2-RNA
3-yes
4-commmon cold and SARS

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48
Q

Genera of coronaviruses that causes the common cold

A

coronavirus

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49
Q

Hentavirus Pulmonary Syndrome

Symptoms start as _____ and then progress to _______.

1-common name:
2-Primary Host:
Transmission:

A
  • fever, headaches
  • hemorrhagic fever, kidney disease, and acute respiratory failure.

1-Sin Nobre Virus (SNV)
2-Deer mouse
3-via inhalation of excrements

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50
Q

Filovirus

1-Genetic material:
2-Envelope?
3-Structure:
4-Most pathogenic of:
5-Important viruses:
A 
1-RNA
2-yes
3-long, threadlike
4-hemorrhagic fever viruses
5-Ebola and Marburg viruses
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51
Q

Filoviruses: Marburg Virus

1-first individuals infected were exposed to:
Reservoir:
2-Initial symptoms include ____ and then progress to ______.

3-Death rate of initial outbreak in 1967:

A

1-African green monkeys
reservoir=fruit bats
2-Initial symptoms include fever,chills, headache, myalgia and then progress to rash on the trunk of the body, nausea, vomiting, chest pain, jaundice, massive internal hemorrhaging, and multi-organ dysfunction.
3-25%

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52
Q

Filoviruses: Ebola

Treatments

A

Supportive treatments:

IV to balance electrolytes

Oxygen therapy

Treat other infections if/when they occur

Experimental vaccines are under development

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53
Q

Filoviruses: Ebola
1-Reservoir:
2-Transmission:

A

1-Reservoir-unknown
2-Transmission-via direct contact through broken skin or mucous membranes with body fluids of infected individuals

NOT spread through the air or food

54
Q

Filoviruses: Ebola

1-symptoms:
2-Diagnosis

A

1-fever, headache, muscle pain, weakness, fatigue, diarrhea, vomiting, abdominal pain, bleeding from the eyes and/ or bruising
survivors can develop antibodies that last for 10 years
2-Blood tests to detect viral antigens

55
Q

Flaviviruses

1-Vector/Transmission:
2-Important viruses/infections:

A

1-Mosquitos

2-Zika, West Nile, Yellow Fever

56
Q 
Flaviviruses: Zika Virus
1-Vector:
2-Reservoir:
3-Transmission:
4-Symptoms:
A

1-Aedes mosquito
2-unknown
3-mosquito bite, sexual contact, crossing the placenta
4-rash,fever, muscle/joint pain, conjunctivitis, usually mild

57
Q

Paramyxoviruses

1-Enveloped?
2-Genetic Material:
3-Infections:

A

1-yes
2-RNA
3-Measles, Mumps, Rubella, RSV

58
Q

Paramyxoviruses: Respiratory Syncytial Virus (RSV)

Causes ______ in young children and is the most significant acute lower respiratory tract infection in _____.

A

bronchiolitis

children under 5

59
Q

Orthomyxoviruses

1-Genetic material:
2-Genera:
3-Transmission:
4-Symptoms:
5-Type of vaccine:
A 
1-RNA
2-Influenza A,B, and C
3-via inhalation of aerosolized particles
4-fever, malaise, headache, body aches
5-killed vaccine (inactivated)
60
Q

Picornaviruses

1-enveloped?
2-Genetic Material:
3-Important:

A

1-no
2-RNA
3-rhinovirus,enteroviruses (polioviruses, Coxsackie virus, hepatitis A)

61
Q

Viral agents that cause the common cold:

A

Coronavirus and rhinovirus

62
Q

Papillomaviruses

1-Genetic material
2-Enveloped?
3-Infects:
4-Infections:
5-Transmission:
A

1-dsDNA
2-no
3-skin and mucous membranes (genital,oral, conjunctival)
4-warts on the skin, Condyloma acuminate (genital warts), Cervical Intraepithelial Neoplasia (CIN) and cancer
5) sexually or via fomites

63
Q

Papillomaviruses:
Types of causes:

1-Warts of the skin:
2-Genital Warts:
3-CIN and Cancer:

A

1-HPV-1 through HPV-4 (skin warts)
2-HPV-6 through 11 (genital warts)
3-HPV-16 and 18 (Cancer)

64
Q

Causative agents of infectious mononucleosis

A

Epstein-Barr virus
and
Cytomagalovirus

65
Q 
Herpesviridae
Types....
1 & 2:
3: 
4:
5:
6 & 7:
8:
A 
1 & 2: Herpes simplex virus (HSV)
3: Varicella-zoster virus
4: Epstein-Barr virus
5: Cytomegalovirus
6 & 7: both can cause roseola
8: Kaposi-sarcoma-related virus
66
Q

What is roseola?

A

Caused by Herpesviruses 6 & 7

red eyes, runny nose, sore throat, and generalized rose colored skin rash that resolves within 48 hours

Life long latent infection of T-cells

67
Q

HSV 1 & 2

1-cause:
2-Transmission:

A

1-oral or genital lesions
2-Transmission:
HSV-1 via kissing or other saliva contaminated items.
HSV-2 via sexual contact

*cause benign disease, but can be fatal if it makes its way to the brain (encephalitis) in neonates or immunocompromised

68
Q

Cytomegalovirus

1-Harbored in the cervix of some:
2-Can cause:
3-Transmission:
4-Symptoms:
5-Histological findings:
A 
1-pregnant women
2-infectious mono
3-sexual contact
4-asymptomatic
5- "owl eye inclusions"-basophilic nuclear inclusion with a clear halo, cell greatly enlarged
69
Q

Most common dural cause for congenital defects.

….Causes microcephaly, intracerebral calcification, hepatosplenomegaly, and rash in neonates

A

Cytomegalovirus

70
Q

Varicella-Zoster Virus

1-Causes:
2-Disease progression:

A

1-Chicken Pox that can lead to Shingles

2-After initial chicken pox, the virus remains dormant in sensory neurons and can reemerge as shingles

71
Q

Shingles?

A

-vesicular lesions similar to chicken pox

Postherpetic neuralgia-chronic pain syndrome that can persist for months to years following shingles due to nerve destruction

72
Q

Hepatitis Viruses

A

All target the liver:

A-RNA (Picornaviridae)
B-DNA (Hepadnaviridae)
C-RNA (Flaviviridae)
D-requires confection with HBV
E-RNA (Hepeviridae)
73
Q

Epstein-Barr Virus

1-Causes:
2-Transmission:
3-Targets:
4-Associated with:
5-In AIDS patients, causes:
A

1-cause: infectious mono
2-Transmission: via saliva
3-Targets: B-lymphocytes
4-Associated with: lymphoma and nasopharyngeal carcinoma
5-In AIDS patients, causes: hairy oral leukoplakia

74
Q

Transmission of Hep C virus

A

Parenteral: IV drug abuse, needlesticks

Sexual contact (not as effective as blood for transmission)

75
Q

HCV

1-Pathigenesis:
2-Symptoms:
3-Diagnosis:
4-Treatment:

A

1-hallmarks of chronic inflammation: inflammatory cells, tissue death, healing through scar formation

2-asymptomatic at first….fever, fatigue, nausea, muscle/joint pain, jaundice (but can remain anicteric)

3-blood tests for antibodies or molecular methods to check genotype of HCV

4-Oral antiviral drugs (daclatasvir and sofosbuvir)….can become “clinically cured”

76
Q

Cirrhosis

1-Etiology:
2-Pathogenesis:
3-Morphology:
4-Treatment:

A

1-alcohol, cryptogenic, hepatitis viruses B,C,D, and hereditary metabolic diseases
2-stellate cells secrete type I and type III collagen as a result of various cytokines secreted from leukocytes due to inflammatory response. The microvasculature is altered and hepatic cells proliferate in clusters 9 nodules.
3-nodules on the liver separated by fibrous septae
4-try and treat the source, hypertension medications, liver transplant

77
Q

Rhabdoviruses

1-infect:
2-Example
3-Diagnosis

A

1-plants, animals, fish, and mammals
2-Rabies
3-nuchal skin biopsy and immunofluorescent test

78
Q

Retroviridae contain ____ that goes against the central dogma to _______.

A

reverse transcriptase

convert RNA to DNA

79
Q

How many individuals are unaware they are infected with HIV?

A

1 in 7

80
Q

1-Retroviridae:
2-Routes of transmission:
3-not transmitted via:

A

1-HIV
2-blood transfusions, needle sticks, intercourse, intrauterine, breast milk
3-kissing, coughing, food, utensils, public bathrooms, swimming pools

81
Q

Retroviridae:

-Disease course

A

-First few weeks, may exhibit flu-like symptoms, but then remain asymptomatic for years while still being contagious. If no antiviral treatment is used it may progress to AIDS

82
Q

Retroviridae:

-Disease process

A

Target T-helper cells.
(GP-120 binds CD4 to enter the cell)

As the virus replicates, infects, and lyses cells, T-helper cells decrease in numbers, which affects both antibody and cell-mediated immune responses
HIV-1 is the most common cause
HIV-2 is less pathogenic

After release from the cells, antibodies and cytotoxic t-cells can help eliminate some of the viruses that are not intracellular yet

83
Q

T-helper cells release cytokines that…..

A
  • Activate macrophage to kill ingested antigens
  • Activate the proliferation and differentiation of B and T lymphocytes
  • Chemotaxis-recruits neutrophils and macrophage to the site of infection
84
Q

Mechanisms by which HIV can escape elimination via the immune response:

A
  • Rapid genetic mutations
  • CD4 T-helper cells are rendered dysfunctional due to the viral infection
  • Memory cells are also impaired by the viral infection
85
Q

HIV is screened via _____ and confirmed by _______.

A

HIV is screened via enzyme immunoassays (EIAs) and confirmed by western blot

It is quicker to detect antigens than it is to detect antibodies

86
Q

Most significant diseases in AIDS patients

A

Kaposi sarcoma-vascular tumor

Pneumocystis jerovecii pneumonia lymphomas

87
Q

Most common parasitic infections in Central Wisconsin

A

-Giardia lamblia and Cryptosporidium

88
Q

Risk factors for parasitic infections

A

poor hygiene
poor sanitation (water/sewage)
use of human feces as fertilizer
world travel/trade agreements

89
Q

General types of parasites:

1-Endoparasites:
2-Ectoparasites:
3-Obligate parasites:
4-Facultative:

A

1-live inside host
2-live outside a host
3-must spend all or part of their lifecycle in a host
4-typically free living, but if they get into a host they can become parasitic

90
Q

Types of Hosts

1-definitive:
2-intermediate:

A

1-one in which the parasite reaches productive maturity-sexual reproduction

2-one in which the parasite passes through its larval stage-asexual reproduction

91
Q

Parasite methods of infection?

A
  • penetration/boring
  • ingestion of cysts,eggs, or larvae
  • bite of a vector
92
Q

Protozoa classes…

1-Lobosea:
2-Zoomastigophorea:
3-Kinetofragminophorea:
4-Sporozoea:

A

1-move via pseudopodia
2-move via flagella
3-move via cilia
4-adult stage is nonmotile

93
Q

Amoeba organisms

A
  • Entamoeba spp
  • Iodamoeba butcshlii
  • Endolimax nana
94
Q

Free living amoeba organisms

A
  • Naegleria fowleri

- Acanthamoeba spp

95
Q

Ciliate organisms

A

Balantidium coli

96
Q

Flagellate organisms

A
  • Giardia lamblia
  • Chilomastix mesnili
  • Dientamoeba fragilis
  • Trichomonas spp
97
Q

Malaria organisms

A

plasmodium spp

98
Q

sporozoa organisms

A
  • Toxoplasma gondii
  • Cryptosporidium parvum
  • Babesia microtti
  • Isospora belli
  • Cyclospora cayetanensis
  • Sarcocystis hominis
99
Q

Hemoflagellate organisms

A
  • Leishmania spp

- Trypanosoma spp.

100
Q

Trophozoite characteristics

A
  • Motile and Feeding
  • found in definitive host Reproducing
  • Unicellular with dark, irregular thickened ring of chamoatin around nuclear periphery and a large eccentric nucleus containing large karyosome
101
Q

Cyst characteristics

A
  • Non-motile and Non-feeding
  • Infective
  • Dorment, protective stage found in environment
  • Can boomlet-nuclear with other inclusions in the body
102
Q

Most common intestinal parasite in the US

A

Giardia lamblia

103
Q

Giardia lamblia

1-trophozoite
2-Cysta

A

1-Trophozoite-“old man face”, ventral sucking disc attaches to GI mucosa, bilateral symmetrical paired structures, 2 anterior nuclei, falling leaf motility with 8 flagella

2-Ovoid Cyst-4 nuclei, cyst wall set off from cytoplasm, clustered nuclei and axoneme

104
Q

Giardia intestinalis

1-Symptoms:
2-Epidemiology:

A

1-mild diarrhea to overt malabsorption syndrome…can have copius light colored, fatty stools in severe cases

2-world-wide; associated with contaminated water

*increases reported in homosexual males

105
Q

Nematodes/Roundworms

General characteristics

A

Humans are definitive host
Thread-like, cylindrical
Buccal cavity on anterior end
Males typically smaller than the males

106
Q

Intestinal Nematodes (8)

A 
1-Enterobius vermicularis (pin worm)
2-Trichuris trichiura (whip worm)
3-Ascaris lumbricoides (large roundworm)
4-Trichinella spiralis (trichina worm)
5-Necator americanus (New World hookworm)
6-Ancylostoma duodenale (Old World hookworm)
7-Strongyloides stercoralis (threadworm)
8-Dracunculus medinensis (Guinea worm)
107
Q

Cestodes/Tapeworms

General Features

A

Tape-like appearance
No respiratory, vascular, or digestive systems
Typically 1 intermediate host in life cycle
ALL are hermaphroditic
Tegument-outer layer that absorbs nutrient

Adults reside inhuman intestinal tract
Have scolex instead of mouth
Stroblia-tapeworm body
proglottid-individual segments that contain both male and female reproductive organs

108
Q

Common Human Cestodes/Tapeworms (4)

A

1-Taenia solium (pork)
2-Taenia saginata (beef)
3-Diphyllobothrium latum (fish)
4-Hymenolepis nana (dwarf)

109
Q

Taenia spp. Characteristics

A

Reside in human intestines and can range from 2-10 meters in length

Humans are the only definitive host

Ingested in undercooked meat containing cystercerci

Diagnostic stage: eggs and proglottids in feces

110
Q

Trematodes/Flukes

General Characteristics

A
  • Non-segmented, flat,and leaf-shaped
  • All adults have 2 acetabula-muscular suckers
  • Nutrients absorbed through tegument
111
Q

2 types of Fluke/Trematodes

A

Hermaphroditic-reside in intestines, liver, and lungs

Unisexual-separate males and female organisms

112
Q

Pathogenic Trematodes…..

1-Liver Flukes:
2-Intestinal Flukes:
3-Blood Flukes:
4-Lung Flukes:

A

1-Fasciola hepatica, Chlonorchis sinensis
2-Fasciolopsis buski
3-Schitosoma spp
4-Paragonimus werstermani

113
Q

General lifestyle of Trematodes

A

Eggs are laid inhuman and then excreted in feces, sputum, or urine

All flukes that parasitize humans require a snail intermediate host

114
Q

Arthropods General Characteristics

A

Live in/on host skin (ectoparasites)

Segmented invertebrate with chitinous exoskeleton and bilaterally pairs joint appendages

Have hemocele-body cavity filled with blood-like substance

115
Q

Most common classes of arthropods

A

Arachnida (ticks, mites, spiders, scorpions)

Crustacea (crabs, lobster, shrimp, copepod)

Insecta (flies, mosquitos, lice, fleas, bugs)

116
Q

Most common arthropod vector for disease in the US

A

Ticks

117
Q

American dog tick/Wood Tick

Dermacentor variabilis

A

vector for Rocky Mountain Spotted Fever and Tularemia

118
Q

Deer/Black-legged tick

A

often become infected with bacteria when feeding on an infected host

Vector for Lymes Disease (Borrelia burgdorferi)

119
Q

Ixodes spp tick is a common vector for which common organisms?

A

1-Borrelia burdorferi
2-Babesia microti
3-Ehrlichia

120
Q

2 major forms of Fungi?

A

1-Yeast-unicelllular, eukaryotic

2-Molds-multicellular, grow hyphae (filamentous), dematiaceous or hyaline

Some are dimorphic

121
Q

Most fungal cultures are incubated at

A

30 degrees C

if a dimorph is suspected, isolate at mold phase and then culture at 37 degrees C

122
Q

Characteristics that differentiate fungi from plants

A
  • lack chlorophyll
  • cell walls contain chitin
  • not truly multicellular
  • heterotrophic (plants=autotrophic)
123
Q

Fungi morphology

Vegetative hyphae
Aerial hyphae

A

Vegetative: food adsorbing (under agar surface)

Aerial hyphae: may support reproductive structures (above agar surfaces)

124
Q

Fungi classification

A 
Opportunistic fungi
Superficial and Dermatophytes (skin,hair,and nails)
Yeast
Subcutaneous mycoses (deeper tissues)
systemic mycoses (organ systems)
125
Q

Most common fungi in the human environment

A

Aspergillus spp

126
Q

Opportunistic fungi are _____. ______ is often inhaled.

Since they are very ubiquitous, they can be common contaminants in ________.

A

Opportunistic fungi are saprobic
(live on decaying plant matter and can become airborne)

conidia is often inhaled

Since they are very ubiquitous, they can be common contaminants in sputum cultures.

127
Q

Most common yeasts that cause human disease

A
  • Candida albicans

- Cryptococcus neoformans

128
Q

Which yeast is positive for germ tube production?

A

Candida albicans

129
Q

Candidiasis

A

C. albicans is normal flora of the mouth, throat, vagina, and lower GI

130
Q

Cryptococcosis infections

1-normal flora?
2-tied to what?
3-treatment?

A

1-Cryptococcus neoformans is not considered normal flora

pulmonary-pneumonia like
Cryptococcal meningitis-pulmonary infection spreads to CNS

2-tied to pigeon droppings

3-Amphotericin B with flucytocin followed by fluconazole

Reed Brooks Diagnostic Microbiology (2 decks)

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