Chapter 14- Exam 3 Flashcards
a disease-causing microorganism
pathogen
Colonization of the body by pathogens
infection
An abnormal state in which the body is not functioning normally
disease
The development of disease
pathogenesis
A description of the disease (or the study of disease)
pathology
The cause of a disease (or the study of the cause of a disease)
etiology
you can have _______ without disease and disease without __________
infection; infection
permanently colonize the host starting at birth, and later through food and contact with others.
normal microbiota
how many more bacteria are found in the body compared to human cells?
There is at least ten times as many bacteria as human cells in the body (approximately 10^14 versus 10^13).
a person’s microbiota weighs _____ g
200
how many species of bacteria live in the human gut and on the skin?
500-1000
How do microbes vary?
Microbes vary with respect to nutrient requirements, optimal growth conditions (pH, O2, temperature, salt, light)
how many microorganisms are pathogenic?
few
are microorganisms on and in the skin dangerous?
Most microorganisms on and in the body are harmless if not beneficial
Colonies of Propionibacterium acnes, found on skin and the conjunctiva.
an oral biofilm
why is it difficult to or impossible to culture normal microbiota organisms?
allow identification bacterial species without cultivation
New DNA sequencing technologies
The collection of microbial genomes of an individual
microbiome
Why is it beneficial to know the microbiome of a person?
Determining the microbiome of people has the promise of correlating differences in microbiome composition with specific syndromes or diseases, like autoimmune diseases, diabetes, and obesity.
Why might different types of bacteria colonize different parts of the body?
nutrient availability (secretions, excretions, dead cells) physical and chemical factors (temperature, pH) defenses of the host mechanical factors (chewing, flushing, mucus, cilia)
dominate the newborn gut
Firmicutes
This group includes Lactobacillus
firmicutes
adapted to feeding on human milk
lactobacillus (firmicutes)
adapted to feed on plant matter
bacteriorides
may be present for days, weeks, or months, then disappear
transient microbiota
come from the environment, don’t get permanently established, and typically don’t cause disease
transient microbiota
Not a problem as long as they don’t displace the normal microbiota
transient microbiota
why does normal microbiota differ among us?
normal microbiota (normal human flora) differ from person to person because: conditions provided by the host at a particular body site vary from one person to another based on numerous factors like age, environment, stress, diet, etc.
what are some locations in the human body of normal microbiota?
skin eyes (conjunctiva) nose, throat, upper respiratory tract mouth large intestine urinary tract reproductive system
bacteria found on the skin
Propionibacterium Staphylococcus Corynebacterium Micrococcus Acinetobacter Brevibacterium
fungi found on the skin
Pityrosporum
Candida
Malassezia
why do skin microbes not become resident?
Most of the microbes in direct contact with skin do not become residents because secretions from sweat and oil glands have antimicrobial properties.
___________ is a resistant barrier, and the _____ pH of the skin inhibits many microbes.
keratin; low
has a relatively low moisture content
skin
bacteria found in conjunctiva
S. aureaus S. epidermidis diphtheroids Propionibacterium Corynebacterium streptococci Micrococcus
a continuation of the skin or mucous membrane, contains basically the same microbiota found on the skin
the conjunctiva/ eye
eliminate some microbes or inhibit others from colonizing in the eye
Tears and blinking
bacteria in the nose
S. aureus
S. epidermidis
aerobic diphtheroids
bacteria in the throat
S. pneumoniae
Haemophilus
Neisseria
Although some normal microbiota are potential pathogens, their ability to cause disease is reduced by _________ __________
microbial antagonism
nasal secretions ____ or _______ many microbes, and mucus and ciliary action ________ many microbes
kill; inhibit; remove
bacteria of the mouth
Staph, Strep Lactobacillus Actinomyces Bacteroides Veilonella Neisseria Haemophilus Fusobacterium Treponema
fungi of the mouth
Candida
What conditions make the mouth an ideal enviroment?
Abundant moisture, warmth, and the constant presence of food make the mouth an ideal environment that supports very large and diverse microbial populations on the tongue, cheeks, teeth and gums.
movements that dislodge microbes?
Biting, chewing, tongue movements and salivary flow
bodily secretion that contains antimicrobial substances
saliva
bacteria of the urethra
Staphlococcus Enterococcus Lactobacillus aerobic diphtheroids Pseudomonas Klebsiella
microorganisms of the vagina
lactobacilli Streptococcus Candida (fungus) Trichomonas (protozoan)
what prevents microbes from attaching to the urethra
Mucus and shedding of the lining prevent microbes from attaching.
_______ mechanically removes microbes from the urethra and vagina
flow
______ and ______ expel microbes from cervix.
cilia and mucus
components of urine that are antimicrobial
pH and urea
The ________ of the vagina inhibits or kills microbes.
acidity
The large intestine contains the largest numbers of resident microbiota in the body because of ________ and _________.
moisture and nutrients
How are microbes prevented from attaching to the lining of the GI tract?
Mucus and regular shedding of the lining prevent many microbes from attaching to the lining of the gastrointestinal tract.
What do mucosa produce?
antimicrobial substances
competition between microbes
Microbial antagonism or competitive exclusion
Candida albicans does what to cause UTIs?
Candida albicans grows in the female urogenital system when the normal microbiotoa is altered resulting in a rise in the normal pH of 4
How do normal microbiota protect the host against pathogenic bacteria?
competing for nutrients
producing substances harmful to invaders (E. coli produces bacteriocins)
changing conditions such as pH and O2
How are Germ-free animal microbiomes different than normal animal microbiomes? How is their diet and nutrition related to this?
Germ-free animals raised in the laboratory live, but have underdeveloped immune systems and are more susceptible to pathogenic infection and serious disease. • Germ-free animals also require more calories and vitamins than do normal animals. • When germ-free animals are repopulated with microbiota from obese animals, they become obese. • When people switch from a low-calorie diet to a highcalorie diet, their microbiome changes.
are live microbes applied to or ingested into the body, intended to exert a beneficial effect.
probiotics
are chemicals that selectively promote the growth of beneficial bacteria
prebiotics
Why are antibiotics not good to use too much? Provide two examples
Antibiotic therapy can eliminate normal microbiota, creating opportunities for pathogenic bacteria to gain a foothold. This is one good reason not to use antibiotics too much. For example Clostridium difficile (C. difficile) can cause problematic gastrointestinal infections (diarrhea, fatal colitis) following antibiotic therapy. Certain lactic acid bacteria (some from yogurt) can help prevent colonization by Salmonella after antibiotic therapy
causes diarrhea linked to 14,000 deaths per year in the US
C. difficile
Define fecal transplant and who it could be beneficial for
Fecal microbiota transplantation (FMT) also known as a stool transplant or fecal transplant is the process of transplantation of fecal bacteria from a healthy donor into a recipient patient. It can be an effective treatment for patients suffering from Clostridium difficile infection.
Explain this graph
The diversity of gut Bacteroides in a patient who took a weeklong course of clindamycin. For nine months, the subject’s gut contained only one type of clindamycin-resistant Bacteroides thetaiotaomicron.
one organism benefits, and the other is unaffected.
commensalism
both organisms benefit. Bacteria such as E. coli synthesize vitamin K and some B vitamins that are absorbed into the bloodstream and distributed for use by body cells.
mutualism
one organism benefits at the expense of the other, such as pathogens.
parasitism
Can normal microbiota be opportunistic pathogens?
Yes
Under certain circumstances the relationship between host and microbe can change and a __________ organism, such as E. coli, can become harmful if it gains access to other body sites, such as the urinary tract.
mutualistic
can gain an advantage if the immune system is compromised, as happens in transplant recipients, cancer patients, and AIDS patients.
Opportunistic pathogens
What pathogen used to be rare before the AIDS epidemic?
Pneumocystis pneumonia
