Microorganisms, Pathogens, and Immune Responses: Key Concepts in Infectious Diseases

Microorganisms, Pathogens, and Immune Responses: Key Concepts in
Infectious Diseases


Microorganisms - correct answer Ubiquitous organisms found in various environments.
Commensal - correct answer Organisms that live in or on a host without causing harm or
contributing to well-being.
Symbiotic - correct answer Organism and host both benefit from the relationship.
Saprophytes - correct answer Bacteria that biodegrade organic material (dead plants and
animals).
Pathogens - correct answer Microorganisms that cause disease by releasing toxins or damaging
host tissue.
Infection - correct answer A disease caused by a pathogen.
Opportunistic infection - correct answer Infections caused by fungi, bacteria, viruses, or
parasites when the immune system is weakened.
Clostridium perfringens - correct answer GI flora that can release toxins or necrotic tissue.
Staphylococcus aureus - correct answer Normal skin flora that can cause infection.
Vector - correct answer Method of infection spread.
Latent period - correct answer Period when organisms lie dormant without causing infection.
Carrier - correct answer People who harbor a latent infection, whether symptomatic or not.
Parasite - correct answer An infectious agent that requires the host to perform functions.
Helminths - correct answer Parasites that derive nutrition from the host's blood.
Immunity - correct answer Protection from infectious pathogens.
Innate Immunity - correct answer Mechanisms that are ready to react to infections before they
occur.
Adaptive Immunity - correct answer Mechanisms that are stimulated by microbes.
Humoral Immunity - correct answer Mediated by B cells which produce antibodies.
Cell-Mediated Immunity - correct answer Mediated by T cells.
Antibody - correct answer Protein capable of binding to a specific antigen.
Antigen - correct answer A molecule on the pathogen that triggers an immune response.

,Epitope - correct answer The antigen site that binds with the antibody.
IgA - correct answer Antibody found in mucosal secretions like saliva and tears.
IgG - correct answer Most abundant antibody, provides initial defense in newborns.
IgE - correct answer Involved in allergic responses and parasitic infections.
IgM - correct answer First antibody produced during an immune response.
Botulism - correct answer A serious infectious disease caused by Clostridium botulinum.
Chlamydia - correct answer Caused by Chlamydia trachomatis, the most common bacterial STI.
Gonorrhea - correct answer Caused by Neisseria gonorrhoeae, infects mucous membranes.
Syphilis - correct answer Caused by Treponema pallidum, a chronic venereal disease.
Staphylococcus aureus Infection - correct answer Causes multiple skin lesions and serious
infections.
Streptococcus pneumoniae - correct answer Most common cause of pneumonia and
meningitis.
Group B Streptococci - correct answer A type of bacteria that can cause infections in newborns.
Acute pharyngitis - correct answer An inflammation of the throat caused by group A
streptococci.
Scarlet fever - correct answer A disease caused by group A streptococci characterized by a red
rash.
Impetigo - correct answer A contagious skin infection caused by streptococci.
Cellulitis - correct answer A bacterial skin infection that causes redness and swelling.
Necrotizing fasciitis - correct answer A severe infection that destroys skin, fat, and tissue.
Streptococcal toxic shock syndrome - correct answer A severe illness caused by toxins produced
by streptococci.
Pneumonia - correct answer An infection that inflames the air sacs in one or both lungs.
Meningitis - correct answer An inflammation of the protective membranes covering the brain
and spinal cord.
Sepsis of newborn - correct answer A life-threatening condition caused by the body's response
to infection in newborns.
Manifestations of bacterial infections - correct answer Heat redness, swelling, pain, fever,
leukocytosis, rapid destruction of soft tissues, toxic shock.

, Rheumatic fever - correct answer A complication of untreated strep throat that can affect the
heart.
Glomerulonephritis - correct answer An inflammation of the kidney's filtering units.
Streptococcal Pharyngitis - correct answer Caused by group A streptococci, marked by edema
and epiglottic swelling.
Gram-negative enteric bacteria - correct answer Bacteria such as Escherichia coli and
Salmonella that can cause infections.
Exotoxin - correct answer Proteins secreted by many bacteria, usually gram-positive.
Clostridium tetani - correct answer A bacterium that causes tetanus, found in soil.
Clostridium botulinum - correct answer A bacterium that causes botulism, often from
improperly canned vegetables.
Vibrio cholera - correct answer A bacterium that causes cholera, leading to electrolyte
imbalance.
Anthrax - correct answer Caused by Bacillus anthracis, often from infected livestock.
Endotoxin - correct answer Proteins within the cell wall that are released during infection.
Lyme disease - correct answer Caused by Borrelia burgdorferi, transmitted via ticks from wild
deer.
Salmonellosis - correct answer Caused by Salmonella sp., resulting from ingestion of
undercooked pork, poultry, or eggs.
Plague - correct answer Caused by Yersinia pestis, transmitted via fleas from rodents.
Tularemia - correct answer Caused by Francisella tularensis, transmitted via ticks from rabbits
or rodents.
Brucellosis - correct answer Caused by Brucella sp., leading to undulant fever and malaise.
Typhus - correct answer Caused by Rickettsia prowazekii; symptoms include chills, cough,
delirium, rash, photophobia, headache, and pain.
Rickettsia rickettsii - correct answer Causes fever, rash, and blood vessel infection.
Rocky Mountain spotted fever - correct answer A disease caused by Rickettsia rickettsii.
Rabies - correct answer Caused by the rabies virus; transmitted through the bile of a rabid
animal, leading to encephalitis.
Prion protein - correct answer Associated with neurodegeneration, particularly in Creutzfeldt-
Jakob disease.