Fungi Types: Yeast and Molds

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Questions and Answers

Which mode of transmission involves skin trauma or mucous membrane exposure?

Ingestion

Absorption

Inhalation

Inoculation (correct)

What is the first step in the fungal culture process?

Direct examination of specimen

Evaluation of fungal growth

Specimen collection and transportation (correct)

Selection and inoculation of media

Which of the following is NOT part of the fungal culture process?

Evaluation of fungal growth

Serological testing

Virus isolation (correct)

Antifungal susceptibility testing

What characterizes the production of both sexual and asexual spores?

Fungal transmission (D) Signup and view all the answers

Which process directly follows the collection and transportation of a specimen?

Direct examination of specimen (C) Signup and view all the answers

What is the appropriate pretreatment method for respiratory specimens?

Liquefaction with mucolytic agents (B) Signup and view all the answers

Which pretreatment method is specifically used for nails?

Cutting into pieces (C) Signup and view all the answers

Which of the following is NOT a method for pretreatment of medical devices?

Centrifugation (D) Signup and view all the answers

Which specimen requires mincing or grinding as a pretreatment step?

Tissue (A) Signup and view all the answers

What pretreatment process is used for body fluids?

Filtration/centrifugation (A) Signup and view all the answers

What type of hyphae has numerous cross-walls?

Septate hyphae (D) Signup and view all the answers

Which type of fungal growth is typically smooth, creamy, pasty, or mucoid?

Yeast (D) Signup and view all the answers

What is the purpose of vegetative hyphae?

Absorbing nutrients (D) Signup and view all the answers

Which of the following describes coenocytic hyphae?

Has few cross-walls (D) Signup and view all the answers

Which pigment characteristics describe hyaline mycelium?

Colorless without stain (A) Signup and view all the answers

What is the visual characteristic of dimorphic fungi?

Exhibits two different forms (D) Signup and view all the answers

What does a racquet hyphae resemble?

A racquet (C) Signup and view all the answers

Which type of hyphae is responsible for holding the conidia?

Aerial hyphae (C) Signup and view all the answers

Which site is NOT a recognized portal of entry for fungal infections?

Muscle tissue (D) Signup and view all the answers

What is the main reason for keeping a specimen moist during transport?

To ensure fungal organisms remain viable (B) Signup and view all the answers

What should be done immediately after specimen collection?

Transport the specimen to the lab right away (C) Signup and view all the answers

Which technique is essential when collecting specimens from a site with normal flora?

Sterile technique (B) Signup and view all the answers

What is the best specimen type for identifying the etiologic agent of a fungal infection?

A specimen from a site of active infection (D) Signup and view all the answers

What is the maximum time allowed for transporting blood specimens at room temperature?

≤24 hr (C) Signup and view all the answers

Which of the following specimen types requires scraping for collection?

Nails (C) Signup and view all the answers

What is the preferred method of collecting cerebrospinal fluid (CSF) before inoculation?

Centrifugation (C) Signup and view all the answers

For respiratory specimens, what is recommended if a patient cannot produce a sputum sample?

Use a nebulizer (A) Signup and view all the answers

What is the maximum time allowed for skin specimen transport at room temperature?

≤24 hr (D) Signup and view all the answers

Which specimen collection requires the deepest scraping using KOH preparation?

Nails (D) Signup and view all the answers

How soon should a urinary specimen be collected after the bladder is emptied?

≤15 min (C) Signup and view all the answers

What should be done to skin before scraping for specimen collection?

Disinfect with 70% alcohol (C) Signup and view all the answers

What type of specimen collection is advised for prostatic fluid?

Inoculation onto media after prostatic massage (A) Signup and view all the answers

Which specimen type should never be refrigerated?

Blood (A) Signup and view all the answers

What is the proper way to collect external ear specimens?

Rotate swab firmly in outer ear canal (D) Signup and view all the answers

What is the maximum time allowed for transporting vitreous fluid?

≤24 hr (A) Signup and view all the answers

When collecting tissue biopsies, what is essential to keep them moist?

Sterile saline (D) Signup and view all the answers

Study Notes

Fungi Overview

Fungi can be categorized into two main forms: yeasts and molds.
Yeasts have a smooth, creamy, pasty appearance and reproduce by budding, resulting in blastoconidia.
Molds exhibit filamentous growth due to mycelia formation.

Hyphae Types

Septate Hyphae: Contains numerous cross-walls, dividing hyphae into compartments.
Coenocytic (Aseptate) Hyphae: Features few or no cross-walls.

Pigmentation in Hyphae

Hyaline Hyphae: Non-pigmented, clear, and transparent; colorless unless stained, appearing blue upon staining.
Dematiaceous Hyphae: Pigmented with black or brown coloration.

Mycelium

Mycelium is a mass of branching, intertwined hyphae important for nutrient absorption.
Aerial hyphae are the filamentous structures that hold conidia, while vegetative mycelium absorbs nutrients from culture media.

Vegetative Hyphae Shapes

Antler Hyphae: Resemble antlers.
Nodular Hyphae: Knot-like formations.
Racquet Hyphae: Shaped like racquets.

Modes of Transmission

Fungi can reproduce via:
- Asexual spores
- Sexual and asexual spores
Transmission can occur through:
- Inhalation
- Inoculation via skin trauma or mucous membranes
- Ingestion

Fungal Culture Process

Important steps include specimen collection, direct examination, media selection, evaluation of fungal growth, serological testing, and antifungal susceptibility testing.

Specimen Collection and Transport

Accurate specimen collection is critical for diagnosing fungal infections:
- Common sites include skin, hair, nails, respiratory tract, gastrointestinal tract, and urinary tract.
- Sterile techniques are essential to avoid contamination.
- Specimens should be kept moist and transported promptly.

Direct Examination Techniques

Direct examination can involve various collection methods, like scraping and using sterile tools for samples.
Hair samples should remain intact, while nails can be collected as scraping or cuttings for better yield.

Pre-treatment of Clinical Specimens

Pre-treatment methods vary based on specimen type, e.g.:
- Blood undergoes lysis and centrifugation.
- Body fluids are filtered and centrifuged.
- Respiratory specimens may require liquefaction with mucolytic agents.

Specimen Handling Guidelines

Ensure proper labeling and immediate processing of specimens.
Specific handling protocols differ for various specimen types, emphasizing timely transport and temperature conditions.

Collected Specimen Types

Common specimen types include:
- Blood and sterile fluids
- Bone marrow
- Catheter samples
- Cerebrospinal fluid (CSF)
- Skin, hair, nails, and respiratory specimens
- Tissue biopsies and vaginal swabs.

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Description

Explore the two major forms of fungi: yeast and molds. Learn about their characteristics, including the presence of septate and non-septate cross walls. This quiz will test your understanding of their structural differences.