Medical Microbiology MMI 133 Lecture 1

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Questions and Answers

Which of the following categories is not one of the major areas of Microbiology?

Mycology

Immunology

Entomology (correct)

Bacteriology

What is the primary stain used in Gram staining?

Crystal Violet (correct)

Acetone

Iodine

Safranin

Which subspecies is an example of E. coli?

EHEC (O157:H7)

EPEC

ETEC

All of the above (correct)

What method is used to differentiate Mycobacterium from other bacteria?

Acid fast stain Signup and view all the answers

Which structural component is primarily responsible for the Gram staining characteristics of bacteria?

Peptidoglycan Signup and view all the answers

What is the purpose of adding iodine during the Gram staining process?

To serve as a mordant Signup and view all the answers

How are bacteria classified into families?

Using ribosomal RNA sequences Signup and view all the answers

What bacterial morphology describes a cluster of spherical bacteria?

Staphylococcus Signup and view all the answers

What is the final step in the Gram staining procedure?

Add Safranin Signup and view all the answers

What is the approximate number of bacteria present in the gut of a healthy adult?

10 trillion Signup and view all the answers

What beneficial role do certain bacteria play in relation to glycans in milk?

They break down glycans Signup and view all the answers

Which group of organisms includes Escherichia coli?

Bacteria Signup and view all the answers

What is a potential outcome of an imbalance in bacterial flora?

Higher risk of infections Signup and view all the answers

What kind of bacteria can lead to tissue damage in a host?

Bacteria with virulence factors Signup and view all the answers

What is the role of a healthy immune system in the context of bacterial balance?

It balances the bacterial ecosystem Signup and view all the answers

Which of the following statements about bacteria is false?

All bacteria are harmful to humans. Signup and view all the answers

Which type of bacteria is Escherichia coli categorized under?

Gram-negative bacteria Signup and view all the answers

What role does iodine play in the Gram staining process?

It acts as a mordant that complexes with crystal violet. Signup and view all the answers

Which statement correctly describes the structure of peptidoglycan in Gram-positive bacteria?

Peptidoglycan in Gram+ bacteria is thicker, ranging from 10-20 times that of Gram-. Signup and view all the answers

What happens during the acetone-alcohol wash in the Gram staining procedure?

It disrupts the peptidoglycan and the associated outer membrane in Gram-negative bacteria. Signup and view all the answers

What is the final step in the Gram staining process for visualizing Gram-negative bacteria?

Counterstaining with safranin. Signup and view all the answers

Which of the following statements is true regarding bacteria?

Bacteria can be classified based on their genetic relatedness. Signup and view all the answers

How does crystal violet behave in the Gram staining process?

It penetrates and sticks to the peptidoglycan layer of all bacteria. Signup and view all the answers

Which of the following is characteristic of Gram-negative bacteria?

Their peptidoglycan is attached to an outer membrane with lipoproteins. Signup and view all the answers

What is the purpose of the Gram stain in microbiology?

To provide a method for classifying bacteria into two major groups. Signup and view all the answers

Study Notes

Course Introduction

MMI 133: Medical Microbiology for Health Professionals, taught by Dr. Judy Gnarpe.
Dr. Gnarpe holds an undergrad in Medical Laboratory Science and a PhD in Clinical Microbiology.
Extensive experience as a clinical microbiologist, teaching health professionals since 2003.

Course Objectives

Understand differences between microorganisms and how they cause diseases.
Learn the mechanisms of antimicrobial actions against microbes.
Gain knowledge about clinical conditions linked to infections.
Explore epidemiology, infection spread, and prevention strategies.

Course Materials

Required textbook: Medical Microbiology for Health Professionals (4th edition).
eClass serves as a central hub for lecture notes, course information, and resources.
Exams are open book; assignments must be submitted via eClass.

Evaluation Breakdown

Midterm 1 (25%): Scheduled for October 1.
Midterm 2 (25%): Scheduled for October 31.
Assignment (10%): Due December 5 at midnight.
Final Exam (40%): Scheduled for December 16.
Bonus 1% for completing the ethics quiz by September 20.

Categories of Microbiology

Bacteriology: Study of bacteria.
Virology: Study of viruses.
Mycology: Study of fungi and yeast.
Parasitology: Study of protozoa and metazoa.
Immunology: Study of immunity and resistance to infections.

Bacterial Ecosystem

Healthy adults host approximately 10 trillion bacteria in the gut, comparable to their own body cells.
Beneficial bacteria break down complex carbohydrates for energy and produce essential vitamins (e.g., K, B12).
Antibiotic treatments can disrupt the balance of bacterial flora, making individuals susceptible to infections.

Bacterial Classification

Domain: Bacteria.
Kingdom: Monera, Phylum: Proteobacteria, Class: Gamma Proteobacteria, Order: Enterobacterales, Genus: Escherichia, Species: coli (E. coli).
Classification is based on genetic relatedness; Genus and species names are crucial (e.g., Staphylococcus aureus, Salmonella typhi).

Bacterial Morphology

Common shapes: Cocci (spherical), Bacilli (rod-shaped), and spiral bacteria (e.g., Vibrio).
Naming and identifying bacteria involve their morphology and genetic characteristics.

Gram Staining

Most significant differential staining technique used for bacterial identification.
Distinguishes bacteria based on cell wall structure: Gram-positive (thick peptidoglycan) versus Gram-negative (thin peptidoglycan, outer membrane).
Steps include applying crystal violet, iodine as a mordant, decolorization with acetone/alcohol, and counterstaining with safranin.

Summary Points

Bacteria are prokaryotic organisms; eukaryotes include plants and animals.
Bacterial shapes are key to their identification; naming system emphasizes genetic relatedness.
The Gram stain remains a vital diagnostic tool to categorize bacteria into Gram-positive or Gram-negative.

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Description

Explore the foundational concepts of Medical Microbiology in this introductory lecture for health professionals. Led by Dr. Judy Gnarpe, learn about the significance of microorganisms in health and disease, and get acquainted with essential terminologies and principles. Perfect for students beginning their journey in medical microbiology.