Patho Exam 2: Chapter 10 Infectious Disease   

What is a fomite? What would be some examples?

Environmental objects, also called fomites, can also act as reservoirs of microorganisms. An unsanitary bathroom surface is an example of a fomite. Ex: Door knobs phones

What is a nosocomial infection?

A patient infection caused by microorganisms inherent to the health-care facility environment; hospital-acquired infection. Nosocomial infections may be difficult to treat because they are often caused by drug resistant bacteria. Hospital personnel often inadvertently spread microbes from one patient to another because of lack of proper hand washing and poor sterile technique.

What is a carrier? Give an example

A person, animal, or plant that serves as a host for a pathogen and can transmit it to others, but is immune to it. Mosquitoes are carriers of malaria. An organism that carries a gene for a trait but does not show the trait itself.

Why is E.coli 0157:H7 strain worse than other strains of E. coli? How is it transmitted? Who are at highest risk for illness?

A specific strain called E. coli 0157:H7 causes severe gastroenteritis and can cause hemolytic-uremic syndrome. This specific bacteria is one of the enterohemorrhagic Escherichia coli ftEHEC).

What is an opportunistic infection?

An infection caused by a microorganism that flourishes because of a host's deficient immune system 1. Thrush and systemic Candida 2. Cryptococcus 3. Histoplasmosis 4. Pneumocystis jiroveci 5. Toxoplasmosis

What are signs and symptoms of C. diff? What is a common cause?

C. difficile is a spore-forming, toxin-secreting anaerobic bacteria. The organisms emit toxins that disrupt the intestinal mucosa, erode the intestinal epithelial cells, and form pseudomembranes that contain necrotic tissue, white blood cells (WBCs), and mucus. The most common predisposing factor is long-term antibiotic use because of consequent alteration of the normal flora in the gut. Contagion between patients is possible; this is a source of nosocomial infection.

What is virulence? What are the factors that can increase the virulence of an organism?

Different pathogens have varying disease-producing potential, which is called virulence. There are various virulence factors that enhance the pathogen's ability to infect the host; examples of virulence factors include pathogenic toxins that destroy host cells and adhesion factors that enhance attachment of the pathogen to the host cells. The severity of infection depends on the virulence of the pathogen and the strength of the host defenses at the time of infection.

How and where do viruses reproduce? What can be used to kill viruses?

Hide and multiply in host cell Difficult to kill with antibiotics because they hide in cells Small size -> ability to escape destruction from phagocytes Use host cell mechanisms for their own survival and replication specific viruses generally infect and reproduce in certain types of cells Example: influenza binds to receptors on respiratory epithelial cells Most can produce strong lymphocyte immune response Some have a latent phase -> lie dormant then activate later (esp. if person becomes immunosuppressed) ex. shingles caused by the chickpox (varicella) virus, (herpes zoster)

what are the 5 immunoglobulins

IgG, IgA, IgM, IgE, IgD

What are the stages of infection? Explain what happens in each stage.

Incubation period: pathogen begins active replication (without symptoms) • Prodromal stage: Initial appearance of symptoms Acute stage: host experiences maximum impact, immune response by the host • Convalescent period: containment of infection, progressive elimination of pathogen Resolution: total elimination of the pathogen without residual signs or symptoms

What is a mycoplasma pneumonia? Who does it most often affect? What are the signs and symptoms?

It is an infection of the lungs from the bacteria Mycoplasma pneumonia (M. pneumoniae). It causes an atypical pneumonia that commonly affects people younger than 40 years. This type of pneumonia is often referred to as "walking pneumonia" because the affected individual does not appear very ill.

antibiotic-resistant bacteria

MRSA: Methicillin-resistant Staphylococcus aureus VRSA: Vancomycin-resistant Staphylococcus aureus. VRE: Vancomycin-resistant Enterococci DRSA:

What is the difference between normal flora and a pathogen?

Normal Microorganisms normally living in/on your body. Some are useful. Many have no effect. Pathogen Pathogens cause disease. All are capable of causing disease if your health and immunity are weakened.

What are vector-borne illnesses?

a living being that can carry the pathogenic organism from the reservoir to the host. not infected with the organism but can transmit the pathogen to the host. Ex: mosquitoes, ticks, flies, fleas and lice.

IgG:

circulates in body fluids, binding antigens, 80% of antibodies in the blood, most protective against infections remains elevated after the acute phase.

IgM:

circulates in body fluids; the first most rapid response to an antigen/infection has five units to pull antigens together into clumps rises and fall during the acute phase.

IgA:

found in secretions & mucous membranes; prevents antigens from entering the body

IgE:

found on mast cells in tissues; starts inflammation; involved in allergy, important in the defense against parasites, elevated in allergic disorders • increased amounts of IgE bind to mast cells causing degranulation release of inflammatory cytokines • eosinophil chemotaxic factor • allergic reactions/ widespread inflammation • s/s (mucus production, bronchoconstriction)

IgD:

found on the surface of B cells; acts as an antigen receptor, not fully understood