Lab Experiment on Microbes and Hand Washing
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Questions and Answers

What is the primary focus of the laboratory experiment described?

  • Studying the genetic makeup of bacterial species.
  • Analyzing microbial characteristics in water sources.
  • Investigating the variety of microorganisms on human bodies and hand hygiene. (correct)
  • Exploring the effectiveness of different cleaning surfaces.

What does the Snyder Test primarily evaluate?

  • The presence of specific bacteria in the mouth. (correct)
  • The overall health of the human microbiome.
  • The effectiveness of hand sanitizers.
  • The genetic diversity of microbial species.

Which of the following best describes the human microbiome?

  • An exclusive group of bacteria within the body.
  • A limited number of species that reside solely in the gut.
  • A collection of human body cells only.
  • A diverse array of microorganisms, including bacteria and fungi, living in and on humans. (correct)

How does the composition of the microbial population differ among individuals?

<p>Composition varies significantly between individuals and body parts. (C)</p> Signup and view all the answers

Which of the following statements about the human gut microbiome is true?

<p>It is characterized by a high degree of microbiome diversity and abundance. (A)</p> Signup and view all the answers

What is the estimated range of bacterial organisms present in the human body?

<p>75 trillion to 200 trillion. (D)</p> Signup and view all the answers

What percentage of bacterial species are typically shared between the right and left hands of a person?

<p>17% (D)</p> Signup and view all the answers

Which of the following materials is mentioned as necessary for the lab experiment?

<p>Snyder Test agar. (D)</p> Signup and view all the answers

What is one of the main uses of bacteria in the medical industry?

<p>Synthesis of antibiotics (B)</p> Signup and view all the answers

Which method is considered the most important for preventing infections in healthcare settings?

<p>Consistent hand washing (A)</p> Signup and view all the answers

What happens if pathogenic bacteria are not controlled in hospitals?

<p>They may cause nosocomial infections. (C)</p> Signup and view all the answers

What is bioremediation?

<p>Using microbes to remove pollutants from environments (D)</p> Signup and view all the answers

What type of infection is commonly associated with bacteria in hospitals?

<p>Nosocomial infections (B)</p> Signup and view all the answers

What does a yellow result in a Snyder test indicate?

<p>High levels of bacteria (D)</p> Signup and view all the answers

How should you label the TSA plate before conducting the hand washing experiment?

<p>Before and After (D)</p> Signup and view all the answers

What is one reason some bacteria survive hand washing?

<p>Some bacteria form protective biofilms. (B)</p> Signup and view all the answers

Which hand cleansing agent is expected to be the most effective at killing bacteria?

<p>10% povidone iodine (C)</p> Signup and view all the answers

What is the purpose of labeling the control test tube in the Snyder test?

<p>To compare with saliva sample (A)</p> Signup and view all the answers

How long should the plates be incubated after sampling?

<p>24-48 hours (D)</p> Signup and view all the answers

Why should students wash their hands before touching agar plates?

<p>To remove surface contamination (D)</p> Signup and view all the answers

What is the role of bacteria in nutrient cycling?

<p>To degrade dead matter and recycle nutrients (B)</p> Signup and view all the answers

What does the abbreviation CDC stand for?

<p>Centers for Disease Control (B)</p> Signup and view all the answers

What is the primary function of the human microbiome?

<p>To break down food and prevent harmful bacteria (A)</p> Signup and view all the answers

What does the term 'common bacterial cores' refer to?

<p>The core bacterial species found in all humans (B)</p> Signup and view all the answers

How does antibiotic use impact the human microbiome?

<p>Antibiotics can alter the balance of bacteria, allowing pathogenic bacteria to grow. (C)</p> Signup and view all the answers

What is fecal transplantation used to treat?

<p>C. difficile infection (D)</p> Signup and view all the answers

What is the suspected connection between obesity and the gut microbiome?

<p>Obese individuals have a higher abundance of bacteria that are more efficient at extracting nutrients from food. (B)</p> Signup and view all the answers

What type of surface is most prone to bacterial colonization in the oral cavity?

<p>Teeth (A)</p> Signup and view all the answers

What is the name of the proteinaceous film that bacteria attach to on teeth?

<p>Pellicle (A)</p> Signup and view all the answers

What is the primary cause of dental caries?

<p>Acid produced by bacteria during fermentation of sugars (C)</p> Signup and view all the answers

Which of the following bacterial species is known to be a primary contributor to dental caries?

<p>Streptococcus mutans (D)</p> Signup and view all the answers

What is the Snyder Test designed to detect?

<p>The ability of bacteria to ferment glucose (B)</p> Signup and view all the answers

What makes the Snyder Test medium favorable for the growth of oral bacteria?

<p>It has a low pH of 4.8. (A)</p> Signup and view all the answers

What is the difference between a positive and negative Snyder Test result?

<p>A positive test indicates the presence of bacteria that ferment glucose, a negative test does not. (D)</p> Signup and view all the answers

Why are individuals with dietary intake of sugars and poor dental hygiene at higher risk for dental caries?

<p>Sugary foods provide a readily available source of energy for harmful bacteria, leading to increased acid production. (A)</p> Signup and view all the answers

How do oral bacteria survive in the low pH conditions of dental plaque?

<p>They have evolved mechanisms to tolerate acidic environments. (C)</p> Signup and view all the answers

What is the significance of the observation that most bacteria are harmless and may even be helpful?

<p>This supports the idea that bacteria are essential for human health. (B)</p> Signup and view all the answers

Which of the following statements is NOT TRUE about the human microbiome?

<p>The human microbiome is identical in all humans. (D)</p> Signup and view all the answers

Flashcards

Human Microbiome

The complete collection of microorganisms (microbiota) residing within and on a human body.

Human Microbiome Metagenome

The genetic makeup of the human microbiome, encompassing all the microbial genomes.

Microbiota

A diverse group of microorganisms, including bacteria, archaea, fungi, protozoans, and viruses, that contribute to the human microbiome.

Bacterial Microbiota

The bacterial population within the human microbiome, which is estimated to be much larger than the number of human cells.

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Supraorganism

Refers to the concept of the human body being a complex system composed of both human and microbial components, acting as a single cohesive unit.

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Microbial Diversity

The variation in the composition of the human microbiome, both between different individuals and between similar body sites of the same individual.

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Diversity of Microbiome Species

The presence of around 900 to 1000 different species of microorganisms contributing to the human microbiome.

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Human Microbiome Research

The study of the microbial communities residing within and on the human body.

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Bacterial Species

Groups of similar bacteria found in a specific environment, like the gut or mouth.

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Common Bacterial Core

The core set of bacterial species commonly found in a population.

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Gut Microbe

A type of microorganism that lives in the gut and helps break down food.

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Pathogenic Microorganism

A type of microbe that can cause disease.

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C. difficile Infection

A condition that can be caused by certain bacteria, often after antibiotic use.

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Fecal Transplantation

The transfer of healthy feces into the gut to restore beneficial bacteria.

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Methanogenic Archaea

A type of microorganism that produces methane, a gas.

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Carbohydrate Harvesting

The process of breaking down food into usable nutrients.

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Stratified Squamous Epithelium

The outermost layer of cells, found in the mouth, skin, and other areas.

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Pellicle

A film of proteins that forms on teeth, providing a surface for bacteria to attach.

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Sugar Fermentation

The process of breaking down sugars into acids, often by bacteria in the mouth.

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Acid

A chemical substance that dissolves enamel, leading to cavities.

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Snyder Test

A test to detect the presence of bacteria that cause tooth decay.

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Pathogenic bacteria

Bacteria that cause disease. They can lead to various illnesses, from mild infections to severe and deadly ones.

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Nosocomial infection

A type of infection acquired in a hospital or healthcare setting. These infections often occur during procedures or due to exposure to bacteria in the environment.

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Bioremediation

The process of using microbes (like bacteria) to clean up pollutants from the environment.

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TSA (Tryptic Soy Agar)

A type of nutrient-rich agar used to grow bacteria in a petri dish.

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Hand Washing Experiment

A method of assessing the effectiveness of different handwashing agents by comparing bacterial growth before and after washing.

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Benzalkonium chloride

A type of common disinfectant used in hospitals and other settings. It is a type of quaternary ammonium compound.

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Povidone iodine

A type of antiseptic commonly used in medical settings. It contains iodine.

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Chlorhexidine gluconate

A type of antiseptic with strong antibacterial properties. It is often used during surgeries and other procedures.

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Bacterial growth

The presence of a significant number of bacteria on a surface or in a sample.

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Effectiveness of handwashing

A measure of the effectiveness of a handwashing agent in reducing bacterial growth.

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Bacteria surviving hand washing

The phenomenon where some bacteria manage to survive despite the application of hand-cleansing agents. This is often due to factors like the agent's concentration, exposure time, or bacterial resistance.

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Bioremediation

Use of microbes (like bacteria) to remove pollutants from the environment.

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Hand cleansing effectiveness studies

Studies conducted to investigate the effectiveness of different hand cleansing agents in reducing bacteria on human skin.

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Study Notes

Lab Experiment: Exploring Microbes and Hand Washing

  • Objectives: Students will explore microbes on the body and evaluate handwashing effectiveness. Key learning points include the Snyder Test and analyzing different hand-cleanser effectiveness.

Materials

  • Snyder Test Agar: Two per group of two students, molten and in a 60°C water bath.
  • TSA Plate: One per student.
  • Hand Cleansers: Antibacterial soap, hand sanitizer, 0.13% benzalkonium, 10% povidone iodine, and 4% chlorhexidine gluconate.

Exercise 1: The Human Microbiome

  • Human Microbiome: A complex collection of microorganisms (bacteria, archaea, fungi, protozoans, viruses) living on and in humans. Bacteria are most abundant, estimated at 75-200 trillion.

  • Microbiome Diversity: The microbiota shows great variation between individuals and even between body parts of the same person. A single hand palm can contain over 150 bacterial species. The gut microbiome also exhibits significant diversity.

  • Microbiome Role: The majority of microbiome members are beneficial, aiding digestion and preventing harmful bacteria. Others can be related to or cause disease (e.g., Staphylococcus, Streptococcus, Enterococcus). Clostridium difficile infection is an example of how an imbalance in the gut microbiome can lead to illness. Factors like diet and genetics influence microbiome composition. Obesity has been linked to increased numbers of Prevotella and Firmicutes bacteria in the gut.

  • Snyder Test: The test seeks to detect microorganisms that contribute to tooth decay. Low pH ( < 4.8) in the medium indicates fermentation of sugars, which is associated with the buildup of bacteria known to cause cavities. A positive Snyder test shows a color change from green to yellow. Key bacteria in dental plaque include Streptococcus mutans and Lactobacillus.

Importance of Handwashing

  • Ubiquitous Bacteria: Bacteria are commonly found everywhere but are not all harmful. They are used in food, medicine, and environmental processes.

  • Pathogenic Bacteria: Some bacteria cause disease, resulting in illness and death. Nosocomial infections, infections acquired in facilities like hospitals, are a particular concern.

  • Handwashing Importance: Handwashing is crucial in healthcare to prevent the spread of pathogenic microbes. Improper hand hygiene leads to infections. Dr. Ignaz Semmelweiss demonstrated the importance of this practice.

  • Hand Cleanser Effectiveness: The laboratory investigation examines the efficacy of different hand cleansers in reducing bacteria on hands before and after washing.

Experimental Procedures for Snyder Test

  • Procedure A: Collect a saliva sample in a sterile tube. Add saliva to one tube and nothing to the "control" tube. Label, and incubate both tubes at 37°C. Analyze for color change.

Experimental Procedures for Hand Washing

  • Procedure B: Students swab the "before" side of a TSA plate with their fingertips to collect data.
  • Cleans hands with 5 designated cleansers.
  • Transfer fingertip swabs samples from "after" washing onto a TSA plate.
  • Plates are incubated and analyzed for bacterial growth.

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Description

In this lab experiment, students explore the presence of microbes on the body and assess the effectiveness of various hand sanitizers. Key concepts include the study of the human microbiome and an evaluation using the Snyder Test. This hands-on activity aims to enhance understanding of microbial diversity and hygiene practices.

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