Chapter 20 Medical Microbiology
when collecting a microbiologic specimen, why is it important to indicate on the laboratory request if the patient is receiving antibiotic therapy?
Antibiotics may suppress the growth of bacteria, a factor that could produce false-negative results.
what is the age range that strep throat is most likely to affect?
in children ages 5-15 years old
the interval of time between invasion by a pathogenic microorganism and the appearance of the first symptoms of the disease
incubation period
Describe the function of oil immersion
provides the highest magnification and is used to view very small structures or detail of larger structure
a small sample or part taken from the body to show the nature of the whole
specimen
true or false a throat specimen is the preferred specimen for a rapid influenza diagnostic test
true
true or false a throat specimen should be collected from the tonsillar area and posterior pharynx
true
true or false chickenpox is caused by a virus
true
true or false droplet infection is the transfer of pathogens from a fine spray emitted from a person already infected with the disease
true
true or false microbiology is the scientific study of microorganisms and their activities
true
true or false strep throat is primarily transmitted through droplet infection and by sharing personal items with an infected person
true
bacteria that have a rod shape
bacilli
List three infectious diseases caused by staphylococcus aureus
boils, carbuncles, pimples, impetigo, and abscesses
describe the procedure for collecting a wound specimen
by inserting the swab into the area of the wound that contains the most drainage and gently rotating the swab from side to side to allow it to absorb completely any microorganisms present.
a disease caused by a pathogen that produces harmful effects on its host
infectious disease
Explain the purpose of diaphragm
intensity of light for proper viewing of specimen especially at a higher magnification, more intense the light when magnification increases
when might a rapid influenza test be performed to diagnose influenza
close to the onset of symptoms as possible, preferably within the first 2 days after symptoms appear.
bacteria that have a round shape
cocci
capable of being transmitted directly or indirectly from one person to another
contagious
the propagation of a mass of microorganisms in a laboratory culture medium
culture
how do antiviral medications work to treat influenza
lessen the severity of influenza and shorten the duration of the disease by 1 to 2 days.
Explain the purpose of eyepiece (ocular lens)
located at the top of the body tube and marked 10x meaning that it magnifies 10 times
What is strep throat?
medically known as streptococcal pharyngitis, a bacterial infection of the back of the throat and tonsils, seasonal in nature during winter through early spring
the scientific study of microorganisms and their activities
microbiology
what is droplet infection?
mode of transmission of contagious disease, refers to an infection indirectly transmitted by contaminated droplets of moisture expelled from upper respiratory tract or infected individual
Explain the purpose of a stage
permits the high form below to pass through the object being viewed and up into the lenses above
bacteria that have a spiral or curved shape
spirilla
what is the purpose of using oil with the oil-immersion objective?
the oil provides a path for the light to travel on between the slide and the lens and prevents scattering of light rays, it improves resolution of the objective lens
what occurs during the incubation period?
the pathogen is growing and multiplying
describe influenza type B
this type can cause influenza outbreaks but is usually associated with a less severe infection than type A.
describe two examples of microorganisms making up the normal flora that are beneficial to the body
1. Inhabit the intestinal tract that feed on other potential harmful microscopic organisms. 2. In the intestinal tract that synthesize vitamin K, an essential vitamin needed by the body for proper blood clotting. 3. If the opportunity arises (lower body resistance), certain microorganisms of the flora can become pathogenic and cause disease
what infection control measures can be taken to prevent the transmission of influenza?
1. Practice good hand hygiene 2. Avoid close contact with infected individuals 3. Try not to touch your eyes, nose, or mouth to prevent the influenza virus from gaining entrance into your body 4. Always cover your nose and mouth when you cough or sneeze. To avoid contaminating the hands, cough or sneeze into a tissue or the crook of the elbow. 5. If infected with influenza, stay home from work, school, or public places for at least 24 hours after the fever has subsided.
how long is an individual infected with influenza contagious?
24 to 48 hours before the onset of symptoms and up to 5 to 7 days after symptoms appear.
what is the incubation period for influenza
Usually two days but it can range from one to four days.
what complications may occur from contracting influenza
Viral pneumonia Secondary bacterial infections such as pneumonia, bronchitis, sinusitis, otitis media. Some of these complications can lead to hospitalization and even death.
harmless, nonpathogenic microorganisms that normally reside in many parts of the body but do not cause disease
normal flora
what is the purpose of a transport medium
prevents drying of the specimen and preserves it in its original state until it reaches its destination
what is the prodromal period of an infectious disease?
short period in which first symptoms indicate approaching disease ex: headache, feeling of illness
List three infectious diseases caused by different types of streptococci
streptococcal sore throat (strep throat), scarlet fever, rheumatic fever, pneumonia, puerperal sepsis, erysipelas, carbuncles, impetigo
what occurs when pathogens invade the body, and what is the response of the body to the invasion?
the tissues so that it can grow and multiply, the body tried to stop invasion with second line of defense mechanisms: inflammation, phagocytosis, and production of antibodies
what may occur if extraneous microorganisms enter a microbiologic specimen?
they grow and multiply, obscure preventing identification of pathogens that are present
describe influenza Type A
this type is most prevalent and us responsible for most annual influenza outbreaks. It causes moderate to severe illness, and at time it can lead to serious complications and death.
describe influenza type C
this type only causes a mild upper respiratory illness and occurs much less frequently than type A and type B.
List 5 common areas of the body from which a microbiologic specimen may be obtained
throat, nose, wounds, cervix, vagina, urethra, rectum
What are microorganisms?
tiny living plants and animals that cannot be seen by the naked eye and must be viewed under a microscope.
list two ways to prevent contamination of a specimen with extraneous microorganisms
to prevent contamination all tools must be sterile, specimen should not contain microorganisms from areas surrounding the collection site
true or false a mixed culture contains two or more types of microorganisms
true
true or false the high power objective has a magnification of 40X
true
true or false the invasion of the body by a pathogenic microorganism is known as infection
true
Describe the function of high power
used for a more thorough study like observing cells in greater detail
Describe the function of low power
used for the initial focusing and light adjustment of the microscope, initial observation, scanning requirement needed for microscope work
Explain the purpose of coarse adjustment
used to obtain an approximate focus quickly
Explain the purpose of fine adjustment
used to obtain the precise focusing necessary to produce a sharp clear image
what is the acute period of an infectious disease?
when the disease is at its peak and symptoms are fully developed ex: fever
what is the best means for preventing an influenza infection?
annual influenza vaccination
a mixture of nutrients in which microorganisms are grown in the laboratory
culture medium
what are the symptoms of influenza
Fever and chills - Muscle aches and joint pain - Sore throat - Runny nose - Nasal congestion - Dry cough - Headache - Joint pain - Anorexia - Fatigue - Gastrointestinal symptoms such as nausea, vomiting, and diarrhea.
what is meant by the following: "microorganisms are ubiquitous"?
Found almost everywhere (air, food, water, soil, in Association with plants, animals, human life)
what factors can increase an individuals risk of developing serious complications from influenza?
Health-related factors Age-related factors Individual with severe influenza symptoms such as pregnant women.
What can occur if E. coli enters the urinary tract?
If it enters the urinary tract as a result of lowered resistance, poor hygiene practices => urinary tract infection.
what defense mechanisms are used by the body to stop the invasion of a pathogen once it has entered the body?
Inflammation, phagocytosis, by white blood cells and production of antibodies
what home care measures can be taken to treat the symptoms of influenza?
- Get plenty of rest - Increase fluid intake to stay hydrated - Avoid the use of alcohol and tobacco - Take over-the-counter medications to relieve the symptoms of the disease.
what is the recommendation for prescribing antiviral medication against influenza?
- oseltamivir (Tamiflu) - zanamivir (Relenza) - peramivir (Rapivab)
what are the symptoms of strep throat
-severe and sudden sore throat - Fever of 101F or higher - Red and swollen tonsils - White patches or streaks on the throat and tonsils - Severe pain and difficulty upon swallowing - Tender and swollen lymph nodes on the sides of the neck - Tiny red spots at the back of the roof of the mouth - Headache
List 5 guidelines that should be followed for proper care of a microscope.
1. Always carry with two hands 2. Do not touch the lens 3. Keep covered to protect from dust 4. Periodically clean the microscope 5. After each use, wipe metal stage clean 6. Keep all lenses spotlessly clean with special cleaner 7. Keep the light source free of dust, lint, & dirt by periodic polishing with lens paper 8. Should be repaired by qualified service person
how is influenza typically diagnosed?
A CLIA-waived rapid influenza diagnostic test (RIDT)
what is a poststreptococcal complication?
A morbid secondary condition that occurs as a result of a less serious primary infection.
List three infectious diseases caused by different types of bacilli
Botulism, tetanus, and gas gangrene, gastroenteritis produced by Salmonella food poisoning, typhoid fever, pertussis (whooping cough), bacillary dysentery, diphtheria, tuberculosis, leprosy, and plague.
How do the symptoms of influenza differ from the symptoms of a cold?
Colds usually develop slowly, whereas the flu has a more sudden onset and the symptoms are much worse.
Explain the purpose of substage condenser
Collects and concentrates the light rays and directs them up bringing to a focus on the object so that it is well illuminated
how should a collection and transport system be stored
Complete a laboratory request form -Sanitize hands and apply gloves -Check expiration date on envelope -Peel back the envelope; remove the cap from the collection tube. Remove the cap/swab unit from the peel-apart envelope. -Using the aseptic technique, collect the specimen. -Insert the swab into the collection tube. -Push the cap/swab in as far as it will go to immerse the swab completely in the transport medium. -Remove gloves, sanitize your hands. -Label the tube with patient's name, the date, the source of the specimen, and your initials. Place the tube in a biohazard specimen transport bag. Place the laboratory request in the outside pocket of the bag. -Chart procedure. -Transport the specimen to the laboratory within 24 hours.
how might the spread of a droplet infection be prevented?
Contagious individuals should cover their mouths and noses while coughing or sneezing
how can these complications be prevented?
Early diagnosis and treatment of strep throat with antibiotics.
what is the advantage of using a RADT to diagnose strep throat in the medical office?
Easy to perform and provide results in a short period of time
what are three benefits that are derived from the influenza vaccine?
Prevent the flu Reduce the severity of symptoms Decrease the risk of complications
list two post streptococcal complications that may occur in a patient with strep throat.
Rheumatic fever or acute glomerulonephritis.
why must a new influenza vaccine be produces each year
Small changes continuously take place in the genetic material of these subtype viruses resulting in new strains developing that replace the older strains.
list two to precautions a medical assistant should take to prevent infecting herself or himself with a microbiologic specimen
The medical assistant must wear gloves when its reasonably anticipated that hand contact might occur with the blood or other potentially infectious materials. -Eating, drinking, smoking, and applying makeup are strictly forbidden when one is working with microorganisms because pathogens can be transmitted to the medical assistant through hand-to-mouth contact.
what are the extraneous microorganisms?
These are undesirable microorganisms that can enter the specimen in various ways,
how is strep throat transmitted from one person to another
Through droplet infection and by sharing personal items with an infected person such as eating utensils.
List two ways in which influenza can be transmitted from one person to another
Through droplet infection from the respiratory tract of an infected individual when they cough, sneeze, or talk.
when is antiviral medication against influenza most effective?
against both influenza virus types A and B and must be started within the first 48 hours of developing symptoms to be most effective.
who should receive an influenza vaccine?
all individual ages 6 months and older
why should a specimen for microbial culture be processed as soon as possible after it is collected?
delay in processing the specimen may cause the death of pathogens or overgrowth of the specimen by microorganisms that are part of the normal flora usually collected along with the pathogen from the specimen site.
true or false a disease that can be spread from one person to another is known as an infectious disease.
false
true or false antiviral medications can be used to prevent influenza
false
true or false escherichia coli normally reside in the urinary tract
false
true or false examination of urine sediment requires the use of the oil immersion objective
false
true or false microorganisms that reside in the body but do not cause disease are known as transient flora
false
true or false staphylococcal infections usually result in pus formation
false
true or false streptococci are round bacteria that grow in pairs
false
true or false the coarse adjustment on a microscope is used to obtain precise focusing of an object
false
true or false the interval of time between the invasion by a pathogen and the first symptoms of disease is known as the prodromal period
false
true or false the purpose of sensitivity testing is to identify the type of microorganism present
false
true or false the purpose of transport media is to provide nutrients for the multiplication of the specimen
false
In what part of the body do E. coli bacteria normally reside?
found among the normal flora of the large intestine.
in microbiology, the act of placing a culture in a chamber that provides optimal growth requirements for the multiplication of the organisms, such as the proper temperature, humidity, and darkness
incubate
List four infectious diseases caused by viruses?
influenza, chickenpox, rubeola, mumps, poliomyelitis, smallpox, rabies, herpes simplex, zoster, yellow fever, hepatitis, the upper respiratory tract including the common cold.
what life processes are performed with a unicellular microbe?
ingestions of food substances, and their use for energy, growth, reproduction and excretion
to introduce microorganisms into a culture medium for growth and multiplication
inoculate
