Applied Medical Microbiology - Week 1-6 Revision for TEST1

A comprehensive set of flashcards covering key concepts in Applied Medical Microbiology from weeks 1 to 6, preparing students for their upcoming Test 1.

What is Applied Medical Microbiology?

The study of microorganisms and their interaction with humans, focusing on their role in health and disease to develop diagnostic, treatment and control strategies.

What does applied medical microbiology focus on in health and disease?

It focuses on developing diagnostic, treatment, and control strategies.

How does applied medical microbiology solve medical problems?

By identifying pathogens, understanding infectious disease transmission, and developing antimicrobial agents.

What are microbes?

Microorganisms that cannot be seen with the naked eye.

What is the importance of classification in microbiology?

It helps in organizing and identifying different types of microorganisms. To ensure smooth communication between different scientists whiile referring to the same microorganism

What are the three domains in the classification of life?

Bacteria, Archaea, and Eukarya.

What is the binomial system of nomenclature?

A two-word system used to name organisms, consisting of the genus (capitalized) and species (not capitalized).

What are the components of a microscope?

Eye piece lens, objective lenses, stage, diaphragm, and illuminator.

What does the term microbiome refer to?

A community of microorganisms living in a specific environment, such as the human body.

What are normal/resident flora?

Microorganisms that continuously inhabit the human body and are usually harmless.

What are opportunistic pathogens?

Normal flora that can cause disease if the host's defenses are compromised.

What does the term pathogenicity mean?

The ability of a microorganism to cause disease.

What is the difference between pathogenic and comensal microorganisms?

Pathogens can cause disease, while commensals typically do not.

What are Gram-positive bacteria?

Bacteria that retain the crystal violet stain during the Gram staining procedure.

How do Gram-positive and Gram-negative bacteria differ?

Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin layer and an outer membrane.

What is the primary function of the bacterial cell wall?

To maintain shape and protect against osmotic lysis.

What is peptidoglycan?

A structural component of the bacterial cell wall made up of sugar and amino acids.

What are endospores?

Resilient structures produced by certain bacteria to survive adverse environmental conditions.

How is DNA replicated in bacterial cells?

DNA replication occurs before cell division, initiated at the origin of replication.

What are the functions of the bacterial cell membrane?

It regulates the movement of substances into and out of the cell.

What is the significance of ribosomes in bacteria?

Ribosomes are the site of protein synthesis during gene expression.

What role do plasmids play in bacteria?

Plasmids carry additional genetic information, such as antibiotic resistance. It is also involved in bacterial conjugation

What are virulence factors?

Molecules expressed by pathogens that enable them to adhere, invade, and evade host defenses.

Describe endotoxins.

Endotoxins are part of the outer cell wall of Gram-negative bacteria and can cause severe immune responses.

What are exotoxins?

Toxins secreted by bacteria that can damage host cells.

What is the purpose of vaccination in the context of infection transmission?

Vaccination helps to break the chain of infection by immunizing susceptible hosts.

What does the term 'infectious dose' mean?

The number of pathogens required to establish an infection in the host.

What are biofilms?

Communities of microorganisms that stick to surfaces and each other, forming a protective matrix.

What is the significance of the Human Microbiome Project?

To understand the composition of the human microbiome and its relationship to health and diseases.

How does temperature affect microbial growth?

Different temperatures can influence metabolism and division rates; there are minimum, optimum, and maximum growth temperatures.

What is the role of oxygen in bacterial growth?

Oxygen is required for aerobic bacteria, while anaerobic bacteria do not require it.

Define the term 'osmotically stable environment' in microbiology.

An environment with balanced osmotic pressure to prevent cell lysis.

What type of culture medium is used for bacterial growth?

Nutritional media, such as agar plates or broth, provide the necessary nutrients for bacteria.

What is the streak plate method?

A technique used to isolate pure bacterial colonies on an agar surface.

What is the pour plate method?

A technique where diluted samples are mixed with molten agar and poured into a petri dish to count colonies.

What is serial dilution?

The process of diluting a sample multiple times to reduce the concentration of bacteria.

Describe the importance of aseptic technique in microbiology.

Aseptic techniques prevent contamination of samples and cultures, ensuring reliable results.

What are common methods of bacterial sample collection?

Blood, urine, sputum, stool, and pus are typical biological samples collected for diagnostic purposes.

Define what is ‘incubation phase’ in microbial growth

The period during which bacteria grow in a controlled environment after inoculation.

Define probiotics.

Beneficial microbes that can confer health benefits when ingested.

What is the significance of diagnosing bacterial infections?

Accurate diagnosis of bacterial infections are essential for timely interventions to offer effective and correct antimicrobials for treatment to control the bacterial infection.

What techniques are used to preserve bacterial cultures?

Short-term refrigeration and long-term freezing or lyophilization are common methods.

What causes antibiotic resistance in bacteria?

Improper use of antibiotics and genetic mutations can lead to resistance development.

Define zoonotic diseases.

Diseases that can be transmitted from animals to humans.

What are the common symptoms of an infection caused by bacteria?

Symptoms can include fever, pain, inflammation, and pus formation.

What is Gram staining used for?

To differentiate bacterial species based on the characteristics of their cell walls.

How does the immune system respond to pathogens?

The immune system recognizes and eliminates pathogens through innate and adaptive responses.

What is the difference between active and passive immunity?

Active immunity is developed through exposure to pathogens; passive immunity is acquired through antibodies from another source.

How do bacteria reproduce?

Bacteria reproduce primarily through binary fission, where one cell divides into two.

What factors can influence the microbiome/microbiota?

Age, environment, and immune activity can alter the proportions of good versus bad bacteria.

What is the difference between commensals and pathogens?

Commensals coexist with the host without causing harm, while pathogens cause disease.

Explain the concept of 'chain of infection'.

The concept encompasses the sequence of events that lead to infection and disease transmission.

What is the role/purpose of epidemiology in public health?

Epidemiology helps identify risk factors, track disease outbreaks, and assess healthcare interventions.

→ access impact of healthcare services

→ identify risk factors (identify things or environmental factors that affect occurrence of disease)

→ help access the effectiveness of new preventative and therapeutic treatments for disease

→ predicts future healthcare needs and guide development of healthcare policies.

Why is accurate microbial identification important in clinical settings?

Correct identification enables targeted treatment and understanding of infection sources.

What are the key components of a bacterial culture medium?

They include carbon, nitrogen, water, minerals, and vitamins to support microbial growth.

What is the role of the complement system in immunity?

The complement system assists in clearing pathogens from the body through lysis and opsonization.

How do bacteria utilize nutrients from their environment?

Bacteria metabolize nutrients for energy, growth, and maintenance of cellular functions.

What causes microbial pathogenicity?

Pathogenicity is caused by the organism's ability to adhere, invade, and evade host defenses.

What is the impact of environmental conditions on the growth of microorganisms?

Environmental factors such as temperature, pH, and osmotic pressure affect microbial growth rate and survival.

How do superantigens affect the immune response?

Superantigens activate a large number of T-cells, leading to a strong immune response and potential tissue damage.

What is the function of the cytoplasmic membrane in bacteria?

• the cytoplasmic membrane helps to facilitate the movement of substances in and out of the cell through diffusion and osmosis which is dependent on osmotic pressure inside the cell and its external environment

Describe the process of transcription in bacterial cells.

Transcription is the synthesis of mRNA from a DNA template by RNA polymerase.

What are the consequences of endotoxin release during bacterial lysis?

Endotoxins can trigger severe inflammatory responses, leading to symptoms such as fever and shock.

How are antibiotics selected based on bacterial classification?

Antibiotics are chosen based on whether the bacteria are Gram-positive or Gram-negative.

Explain the significance of nutrient agar in microbiology.

Nutrient agar serves as a basic medium to cultivate a wide variety of non-fibrous bacteria.

What are differential media used for?

Differential media allow the distinction of different bacteria based on their biochemical characteristics.

What characteristics define bacterial cells versus eukaryotic cells?

Bacterial cells are prokaryotic; they lack a nucleus, are usually unicellular, and are generally smaller than eukaryotic cells.

What is the function of enzymes secreted by bacteria?

Bacterial enzymes can aid in the invasion of host tissues and degradation of host defenses.

What role do phagocytes play in the immune system?

Phagocytes engulf and destroy pathogens as part of the immune response.

What distinguishes pathogenic bacteria from non-pathogenic bacteria?

Pathogenic bacteria can cause disease, whereas non-pathogenic bacteria do not typically cause harm.

List factors that can increase virulence in pathogens.

Factors include the ability to adhere to host cells, produce toxins, invade tissues, and evade the immune response.

What is the role of antigens in microbial infections?

Antigens trigger an immune response, leading to the production of antibodies by B-cells.

How are gram-positive and gram-negative bacteria classified based on cell wall structure?

Gram-positive bacteria have a thick peptidoglycan layer; Gram-negative bacteria have a thin layer and an outer membrane.

Discuss the importance of environmental sanitation in controlling infectious diseases.

Good sanitation practices reduce pathogen transmission and support public health efforts.

What is a pathogenic process?

A pathogenic process is a sequence of events that lead to disease development following the invasion of a host.

What role do cytokines play in the immune response?

Cytokines are signaling molecules that mediate and regulate immunity, inflammation, and hematopoiesis.

What is the significance of bacterial motility in infection?

Motility allows bacteria to navigate environments, enhancing their ability to infect and colonize hosts.

How do vaccines stimulate an immune response?

Vaccines present antigens to the immune system, prompting the body to produce specific antibodies.

What is the relationship between microbial virulence factors and host defenses?

Virulence factors enable pathogens to overcome host defenses, leading to successful infection.

What can influence the efficacy of antibiotics against bacteria?

Factors include the type of bacteria, the mechanism of action of the antibiotic, and the presence of resistance mechanisms.

What constitutes the innate immune response?

The innate immune response includes physical barriers, phagocytes, and inflammation, providing immediate defense.

Explain the method of prevention for transmission of sexually transmitted infections.

Prevention methods include safe sex practices, vaccination, and regular screening.

What are the common methods used for bacterial identification in laboratories?

Common methods include gram staining, biochemical tests, and molecular techniques like PCR.

What is the significance of maintaining proper laboratory techniques?

Proper techniques prevent contamination, ensure accuracy in results, and uphold safety standards.

Discuss the impact of antimicrobial resistance on public health.

Antimicrobial resistance complicates treatment, increasing morbidity and mortality rates due to previously treatable infections.

What are the common symptoms of an infection?

Common symptoms can include fever, pain, swelling, and redness at the infection site.

What factors contribute to the spread of infectious diseases in communities?

Factors include population density, hygiene practices, healthcare access, and environmental conditions.

Describe the mechanism of action for cytotoxins.

Cytotoxins damage or kill host cells, leading to tissue injury and facilitating infection.

What is the role of phagocytosis in innate immunity?

Phagocytosis is the process by which immune cells engulf and digest pathogens.

What is the significance of adherence in bacterial colonization?

Adherence is crucial for bacteria to establish infections by binding to host cells.

What techniques are used to test for antibiotic susceptibility?

Techniques include disk diffusion, broth dilution, and E-test methods.

Explain how bacterial infections can be diagnosed.

Diagnosis can be made through sample collection, culture, microscopy, and molecular techniques.

What is the public health importance of understanding zoonotic diseases?

Understanding zoonotic diseases is vital for preventing transmission between animals and humans.

How are culture media selected based on bacterial growth requirements?

Culture media are chosen based on the nutritional and physical needs of the targeted bacteria.

Describe the significance of temperature in bacterial cultures.

Temperature influences enzyme activity and overall growth rate in bacterial species.

What are the key characteristics of opportunistic pathogens?

They are typically non-pathogenic but can cause disease in immunocompromised individuals.

What is the purpose of differential media like MacConkey agar?

To distinguish between bacteria based on their specific biochemical characteristics.

What is a pure culture?

A culture that contains only one type of microorganism, free from contamination.

What is a pathogenic dose (ID50)?

The number of pathogens needed to infect 50% of a host population.

What testing is done to ensure pharmaceutical products are free from endotoxins?

The Limulus amebocyte lysate (LAL) test is used to detect endotoxin contamination.