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What is the significance of normal bacterial flora?
Normal flora protects from infection, aids in metabolism, synthesizes vitamins, can be disrupted by antibiotics, and may confuse laboratory results.
What is an opportunistic pathogen?
Microorganisms that can cause disease in individuals with compromised immune systems.
What are the two major types of host defenses against bacterial infections?
Mechanical barriers and immune responses.
Describe the role of phagocytosis in host defense.
Phagocytes like macrophages and neutrophils engulf and destroy bacteria.
What are exotoxins?
Proteins produced by bacteria that can cause damage to host tissues and are released into the environment.
What is the difference between passive and active immunization?
Passive immunization uses preformed antibodies for immediate protection, while active immunization stimulates the immune system to generate antibodies.
What is the difference between Gram-positive and Gram-negative bacteria?
Gram-positive bacteria have a thick peptidoglycan layer, while Gram-negative bacteria have a thin layer and an outer membrane.
What is antibiotic resistance?
The ability of bacteria to resist the effects of antibiotics that once inhibited them.
What are the mechanisms of antibiotic resistance?
Intrinsic resistance and acquired resistance, including target alteration and inactivating enzymes.
What role do antigen-presenting cells (APCs) play in the immune response?
APCs help to initiate the immune response by presenting antigens to T-cells.
What is the significance of the primary immune response?
It is the initial response to a new antigen, involving a lag period before antibody production.
What are the two major systems of specific immunity?
Humoral immunity and cell-mediated immunity.
What type of bacteria is Staphylococcus aureus?
A Gram-positive cocci that can be pathogenic and cause infections in humans.
What are the common diseases caused by Streptococcus pyogenes?
Acute tonsillitis, skin infections, and puerperal fever.
What characterizes Neisseria meningitidis?
Gram-negative cocci that can cause severe infections like meningitis and septicemia.
What are the main types of culture media used in microbiology?
Nutrient media, selective media, differential media, and enrichment media.
How are viral infections generally diagnosed?
Through serological assays, antigen detection, or cell culture methods.
What is the purpose of immunofluorescence microscopy?
To detect specific antibodies bound to antigens in a sample using fluorescent dyes.
What is a bacteriophage?
A virus that infects and replicates within bacteria.
What is the primary function of antibodies?
To neutralize pathogens or mark them for destruction by other immune cells.
What is the role of T-helper cells in the immune response?
T-helper cells activate B cells and cytotoxic T cells, facilitating the immune response.
What is genetic transformation in bacteria?
The uptake and incorporation of free DNA from the environment into a bacterial cell.
What is the mechanism of action of antibiotics targeting cell wall synthesis?
They inhibit the formation of peptidoglycan, essential for bacterial cell wall structure.
Name a common laboratory technique to identify bacteria.
Gram staining, which distinguishes bacteria based on cell wall characteristics.
What is the relationship between antibiotics and the microbiome?
Antibiotics can disrupt the normal microbiome, leading to secondary infections.
What are beta-lactams?
A class of antibiotics that include penicillin, targeting cell wall synthesis in bacteria.
What are the pathogenic mechanisms used by bacteria?
Adherence, invasiveness, and toxin production.
What is the significance of the M-protein in Streptococcus pyogenes?
It is a virulence factor that inhibits phagocytosis and contributes to the bacteria's pathogenicity.
What is the role of lysozyme in the immune response?
An enzyme found in secretions like tears that breaks down bacterial cell walls.
What are the consequences of compromised host defenses?
Increased likelihood of infections from normally non-pathogenic organisms.
How does the incidence of antibiotic resistance vary by region?
It often correlates with antibiotic usage practices in agriculture and human health.
Why is it important to understand mechanisms of antibiotic resistance?
To develop effective treatment strategies and new antibiotic agents.
What is the role of macrophages in the immune system?
They perform phagocytosis to engulf and destroy pathogens.
What does a serological reaction demonstrate?
The presence of antibodies against specific pathogens in serum.
What is the impact of environmental factors on microbial growth?
Temperature, pH, oxygen levels, and other conditions influence microbial metabolism.
What methods are used to preserve bacterial cultures over the long term?
Freezing in liquid nitrogen, special freezers, or lyophilization.
What characteristics define the term 'pathogenicity'?
The ability of a microorganism to cause disease.
List the two types of cell-mediated immunity.
Cytotoxic T cell responses and helper T cell responses.
What is a conjugate vaccine?
A vaccine that combines a poorly immunogenic polysaccharide with a protein to improve immune response.
What is the effect of bacterial fimbriae?
They facilitate adherence of bacteria to host tissues.
How can hospital-acquired infections be prevented?
By maintaining strict asepsis and hand hygiene practices.
What are the key characteristics of viruses?
Composed of nucleic acids plus a protein coat and require a host cell for replication.
Describe one challenge in diagnosing viral infections.
Inapparent infections can occur with no obvious symptoms.
What does antibiotic misuse in agriculture contribute to?
Increased prevalence of antibiotic-resistant bacterial strains.
What is the outcome of the interaction between host defenses and bacterial pathogenicity?
Determines the result of an infection, whether it leads to disease.
How do vaccines stimulate the immune system?
By introducing antigens to provoke primary and secondary immune responses.
What is septicemia?
The presence of bacteria in the blood leading to systemic symptoms.
What are general characteristics of viruses covered in microbiology?
Structure, replication cycle, and classification of respiratory and enteric viruses.
What defines the term 'nosocomial infections'?
Infections acquired in a hospital setting.
What is the significance of effective cleaning, disinfection, and sterilization protocols in health sciences?
To minimize the risk of hospital-acquired infections.
