Microbiology Midterm/Final Q2 Flashcards
Movement of water when a bacterial cell is isotonic
Isotonic: Equilibrium (solute outside cell= same concentration as inside)
Cell in isotonic solution remains unchanged
Water enters and leaves the cell at the same rate (no net change)
exercising the same osmotic pressure that are within the cell
Movement of water when a bacterial cell is hypertonic
Bacterial Cell in a hypertonic solution= moisture leaves the cell and shrivel up
The solute concentration outside of the bacterial cell is higher than the solute concentration inside of the bacterial cell
Hyper (above or more)
Most bacterial cells placed in a hypertonic solution shrink and collapse or undergo plasmolysis
Movement of water when a bacterial cell is hypotonic
Will implode (solute outside cell= lower than inside cell)
Cell in hypotonic solution= enters the cell and fills
The solute concentration outside of the bacterial cell is lower than the solute concentration inside of the bacterial cell
Hypo (less or under)
Most bacteria live in hypotonic solutions, and swelling is contained by the cell wall
Cells with weak walls may undergo osmotic lysis
Cell may expand and burst; plamoptysis; osmotic lysis
Metabolism
the sum of all the chemical reactions within a living organism
Catabolism
✅destructive phase of metabolism
- furnish the energy needed to drive anabolic reactions
- the reactions are exergonic(produce more energy than they use)
- Catabolic reactions are coupled to ATP synthesis
Anabolism
✅ constructive phase of metabolism
- Anabolic reactions are coupled to ATP breakdown
- reactions are endergonic (require an input of energy)
Enzymes
biological catalysts
enzymes are specific in the kind of substrate that they will catalyze
Format for naming enzymes
Substrate name as the prefix
Suffix usually “ase”
duration of an enzyme
the loss of an enzymes characteristic three dimensional shape
Lock and Key Mechanism
enzyme and the substrate have a specific complementary geometric shapes that fit exactly into one another
Denaturation
- the process of necrosis that includes cellular swelling
✅ changes of the nature of cellular proteins - molecular structure is changed due to: heat, radiation, pH changes, or other mechanisms that destroy or diminish their original properties
Sterilization
removal or destruction of all forms of microbial life; including endospores
Disinfection
destruction of vegetative pathogens; destruction of pathogenic organisms
Disinfectant
The chemical or physical agent would be called a disinfectant
Generally used on inanimate objects or surfaces
Contamination
act of introducing disease or infectious microorganisms into or on normally sterile objects
Germicide
Agents that kill a variety of different types of microorganisms, but not necessarily their spores.
bactericide
Agents that kill bacteria but not necessarily their spores.
Fungicide
agent that destroys a fungus; molds and yeasts
Viricide
Agents that destroys viruses.
Insecticide
Agents that kill insects.
Larvacide
Agents that kill larvae, which are wormlike forms of newly hatched insects.
Fumigation
use of poisonous fumes or gases to destroy living organisms; especially rodents, insects (vermin); may be used to disinfect an entire room
Infestation
invasion by animal parasites/ macroscopic organisms (ie., helminths like tapeworms, roundworms, and flukes)
Bacteriostasis
inhibiting the growth of bacteria
Sepsis
microbial contamination
Antisepsis
- The process of microbial growth being inhibited
- The absence of microbial contamination
- A condition free from germs, infections, or any form of microbial contamination
Methods of microbial control
Scrubbing
Heat
Dry Heat
Cold
Desiccation
Osmotic Pressure
Radiation or Light
Scrubbing
Method of microbial control
Washing hands
Washing inanimate objects or surfaces
Moist Heat
Method of microbial control
- Boiling water
- More effective then dry heat
- Destroys most microorganisms, but may not kill some spores and viruses
Free flowing steam
Method of microbial control
Type of Moist Heat
- 100 degrees Celsius for 30 minutes to kill most vegetative pathogens
- Destroys most microorganisms, but may not kill some spores and viruses
Autoclave
Method of microbial control
Type of Moist Heat
- apparatus for sterilization utilizing steam under pressure
- reliable sterilization technique
Dry Heat
Method of Microbial Control
✅ Direct flaming for sterilization
- Mechanism: oxidation of cellular compounds and enzymes
- reliable sterilization technique
Cold
Method of microbial control
✅ Refrigeration or freezer
✅ Bacteriostatic: enzyme activity diminishes, and only slows microbial growth
Desiccation
Method of microbial control
✅ Absence of water
- Water is required for most chemical metabolic reactions in bacteria
- Microorganisms cannot grow where water is very limited or absent
Osmotic pressure
Method of microbial control
✅ The pressure required to prevent the net flow of water across a semi-permeable membrane.
- Osmotic pressure is high in many embalming fluids, which is one of the reasons that it retards microbial decomposition and decreases the spread of infectious disease from the deceased to the public.
Radiation or light
Method of microbial control
✅ UV light damages the DNA
- Visible light; ROY G BIV (violet is most destructive)
Key factors influencing the action of disinfectants
- Nature of the disinfectant
- Concentration of the disinfectant
- Nature of the material to be disinfected
- Number and kind of microorganisms
- Time of exposure (contact time)
- Temperature during exposure
- pH of the disinfectant
Desirable qualities of an ideal disinfectant
Ability to attack most types of microorganisms
Rapid action
Low toxicity to body tissues
Effective in the presence of organic matter
Stability
Harmless to fabric and metal
readily available and inexpensive
High penetrating power
Disinfectants that may be used in a mortuary setting
Halogens
Hypochlorites (chlorine)
Iodophores (iodine)
Alcohols
Aldehydes
Phenolic compounds
Quaternary ammonium compounds
✅ SURFACE TENSION REDUCERS; Benzylalkonium Chloride
- Also Named: QUATS
- they work their way between microbes and a surface and “lift” the microbes so that they can be removed with the wash water, water spreads more easily over a surface; lipolytic
Halogens
✅ oxidizing agents (alter cellular enzymes, and inhibit protein function)
- Group VII of the Periodic Table
- Halogens are extremely reactive elements because of their electron configuration
Hypochlorites (chlorine)
- Sodium hypochlorite (NaOCl)
- Chlorine is used in the form of sodium hypochlorite in a 5 percent concentration in household bleach
Iodophores (iodine)
✅ Iodine in a detergent or tincture of iodine
- detergent loosens microbes from the skin surface and the iodine kills them
Alcohols
✅ DENATURE proteins; lipolytic
- 70% aqueous solution more effective than a concentrated solution
-may be used as an antiseptic on the skin or as a disinfectant by immersing instruments in it - Mechanism: denature enzymes; and aqueous solutions are more effective than concentrated solutions because the water aids in the denaturation process; also dissolves lipids
Ethyl Alcohol
Type of alcohol
(ethanol; grain alcohol)
usually in a 70 percent solution
Isopropyl alcohol
Type of alcohol
(isopropanol; rubbing alcohol)
Aldehydes
- REDUCING AGENTS; inactivate proteins by forming covalent cross links between proteins
- Very effective antimicrobials
- Mechanism: inactivates proteins by forming covalent cross-links with organic functional groups on proteins; aldehydes react with amino groups (in proteins) and nucleotides, linking them together and changing the structure of the chemical compound
Formalin
Type of Aldehyde
(formaldehyde solution)
37% aqueous solution of formaldehyde gas by weight; 40% by volume
Glutaraldehyde (cold or liquid sterilizer)
Type of Aldehyde
Sporicidal in 3-10 hours
- commonly used as a cold sterilizing agent for surgical instruments
Phenolic compounds
✅ denaturing enzymes; lipolytic
- Phenol (carbolic acid)
- Phenol derivatives are used in mouthwashes, soaps, lotions, toothpastes, many household cleaners
Phenol coefficient
✅ Comparing the effectiveness of a water-soluble disinfectant to the effectiveness of phenol
- Equal to 1 – disinfectant has the same effectiveness as phenol
- Less than 1 – disinfectant is less effective than phenol
- Greater than 1 – disinfectant is more effective than phenol
cresol
Type of Phenolic compound
Lysol
Good surface disinfectants
hexachlorophene
Type of Phenolic compound
Good antiseptic
Normal Flora
microorganisms that establish residence but do not produce disease under normal conditions.
Microbial antagonism:
✅ inhibition of one microorganisms growth (pathogens) by the presence of another (normal flora).
- Normal flora benefit the host by preventing the overgrowth of harmful microorganisms
- mutual opposition or contrary action
- Competing for nutrients and space; Producing toxins; Producing pH changes
Commensalism
Type of Symbiotic Relationship
✅ one organism benefits and the other is unaffected
- commensalism exists when one organism gains some benefit, such as protection or nourishment, and the host is not harmed.
Mutualism
- different species live in close association and mutual each other
- type of symbiotic relationship
Parasitism
the host is harmed, while the parasite receives some benefit.
Synergism
the harmonious action of two organisms, producing an effect that neither could produce alone
Symbiotic/Symbiosis
organisms live in close nutritional
relationships; required by one or both members
when two or more different species or organisms live together in close association
– Mutualism
– Commensalism
– Parasitism
Non-symbiotic
– organisms that are free-living
and relationships are not required for survival
- Synergism
– Antagonism
Pathology
study of the nature and cause of disease, which involves changes in structure and function.
Etiology
the study of the causes of disease.
Pathogenesis
the origin and development of a disease.
Pathogenicity
the relative capacity of a microbe to cause damage in a host
the ability to produce pathological changes and disease.
Disease
a pathological condition of the body that presents a group of clinical signs and symptoms that sets the condition apart as an abnormal entity differing from other normal or pathological body states.
Infection
the state or condition in which the body or part of it is INVADED BY A PATHOGENIC AGENT that, under favorable conditions, multiplies and produces injurious effects.
True pathogen
microorganism that routinely causes disease upon entering the host; real or genuine disease-causing microorganisms.
Opportunistic pathogen
A bacteria that do not cause disease in their normal environment, but may become pathogenic if the conditions or state of health of the host changes.
Drug fast microorganism
- resistance of a microorganism to the action of a drug or drugs.
✅ Drug-resistant strains (drug-fast strains) - Example: Staphylococcus aureus (MRSA); methicillin resistant Staphylococcus aureus
Symptom
subjective changes caused by disease that are felt by the patient but are not directly measurable.
Examples: pain, headache, malaise
Sign
objective changes caused by disease observed by a physician
Examples: fever, lesions, swelling
Syndrome
a group of signs and symptoms associated with a particular disease.
Communicable/contagious
a disease that may be transmitted directly or indirectly from one person to another.
Noncommunicable
a disease that is not transmitted from one person to another.
Epidemiology
the science that studies when and where diseases occur and how they are transmitted.
(think of the study of epidemics (outbreaks of disease))
Notifiable or reportable disease
a disease that physicians must report to the U.S. Public Health Service.
Incidence
Frequency over a period of time
the FREQUENCY or occurrence of a disease over a PERIOD OF TIME and in relation to the population in which it occurs; the number of people in a population who develop a disease during a particular time period.
Prevalence:
the FRACTION of a population having a specific disease at a given time; prevalence takes into account new and old cases.
Sporadic disease
a disease that occurs occasionally in a random or isolated manner.
endemic disease
disease that occurs continuously in a particular region.
Epidemic Disease
appearance of an infectious disease or condition that attacks many people at the same time in the same geographical area; higher than a normal appearance of an infectious disease within a given population
Pandemic Disease
a disease affecting the majority of the population of a large region or one that is epidemic at the same time in many different parts of the world; worldwide epidemic.
Acute Disease
disease having a rapid onset, generally severe signs and symptoms, and a short course; rapid onset and short duration.
Latent disease:
Asymptomatic
disease is existent without manifesting itself; no outward signs and symptoms.
Chronic disease:
a disease of long duration; slow onset and long duration.
Local infection:
infection caused by germs lodging and multiplying at one point in a tissue and remaining there.
systemic infection
a general infection; an infection affects the entire body.
Focal Infection
infection where organisms are originally confined to one area but enter the blood or lymph vessel and spread to other parts of the body
Nosocomial infection
A nosocomial infection is a hospital-acquired infection
an infection that develops during the course of the hospital stay and was not present at the time the patient was admitted.
Bacteremia
the presence of bacteria in the blood.
Septicemia
condition characterized by the multiplication of bacteria in the blood.
Viremia
the presence of viruses in the blood.
Primary infection
the “first” infection that a host has after a period of health; an acute infection that causes the initial illness.
Secondary infection
infection caused by a different organism than the one causing the primary infection; once the primary infection weakens the host, a secondary infection caused by a different organism can develop.
Mixed infections
infection caused by two or more organisms.
Subclinical infection
pertaining to a period before appearance of typical signs and symptoms of a disease.
Exogenous infection
arises from microorganisms transmitted from the outside of the body.
Endogenous infection
produced or arising from within the body
for example the normal flora inside the gastrointestinal tract.
Carriers
organisms that harbor pathogens and transmit them to others.
Passive carriers
do not exhibit signs and symptoms of the disease
Active carriers:
exhibit signs and symptoms of the disease
Convalescent carriers
recovering from a clinically recognizable form of a disease; have not returned to their original state of health.
Chronic carriers
transmit pathogens for longer than a year.
Zoonosis
diseases that occur primarily in wild and domestic animals and can be transmitted to humans
What is the purpose for Modes of transmission?
For a disease to spread, the disease-causing pathogen must be able to move from its infected reservoir to its next potential host
Direct contact transmission
Mode of transmission
1) Physical contact; person to person
2) droplet transmission coughing, sneezing;
3)Congenital transmission; placental or in the birth canal
Indirect contact
Mode of transmission
- Ingestion: contaminated food/water
- Airborne transmission
- Inanimate objects
- insect vectors
Fomites
inanimate objects that can spread infection.
Examples: towels, bedding, keyboards, telephones, doorknobs, needles, etc
Types of Insect vectors
1) Mechanical vectors- pathogen is carried on the outside of the insect vector. (Bee spreading pollen)
2) Biological vectors- generally involve an insect bite; the insect vector harbors the pathogen and the pathogen may actually carry out its life cycle in the insect vector and/or the host. (mosquito biting you)
Five portals of entry and exit by which pathogens may enter or exit the body
Skin and mucous membranes
Respiratory tract
GI/Digestive tract
Genitourinary tract
Placenta
Vehicles of exit for pathogens
Feces
Urine
Semen
Vaginal Secretions
Sputum
Saliva
Blood
Pus
Tears
Nonspecific defense mechanisms of the host
Mechanical defenses
Physiological defenses
5 Mechanical defenses of the host
skin/Mucous membranes
Normal flora
Tears and blinking
Ciliary escalator
Flushing action of urine
Physiological defenses of the host
- Inflammation
- Phagocytosis
- Body secretions
- Lysozymes- digestive enzymes
- Gastric juices- HCI (hydrochloric acid)
- interferons - stops spread of viruses
- Complement system
Chain of infection
Causative agent; pathogen
Reservoir in which the pathogen can survive; human host
Portal of exit; to leave reservoir
Mode of transmission; from reservoir to new host
Susceptible host
Known factors influencing the occurrence of disease
Virulence of organism
Portal of entry- preferred portal of entry
Number of organisms present
Resistance of the host
Virulence
The ability of a microorganism to survive (and cause damage to its host)
the relative power and degree of pathogenicity possessed by the organisms to produce disease. (pathogen)
Attenuation
the reduction of a microorganism’s virulence
Resistance
the body’s ability to defend against a pathogen
the sum total of body mechanisms that interpose barriers to the progress of invasion, multiplication of infectious agents, or damage by their toxic products (host)
Susceptibility
being susceptible; having little resistance to a disease or pathogen (host)
Characteristics of bacterial toxins
They are poisonous
Toxigenicity
the ability to produce toxins
Toxemia
Distribution of poisons throughout the body
Effects toxins might have on the host
Fever
Circulatory system disturbances
Diarrhea
Shock
Inhibit protein synthesis
Nervous system disorders
Damage cell membranes
Two primary types of bacterial toxins
extotoxins
Endotoxins
Exotoxins
Toxins produced by a microorganism and excreted into its surrounding area
Proteins Produced and secreted into surrounding medium
Soluble in bodily fluids, so they can easily diffuse into the blood and are rapidly transported throughout the body
Heat labile- sensitive to the effects of heat
Primarily produced by gram positive bacteria
Three types of exotoxins
Cytotoxins- kill host cells or affect their functions
Neurotoxins- interfere with normal nerve impulses
Enterotoxins- affect host cells lining the gastrointestinal tract
Body produces antibodies called antitoxins that provide immunity to exotoxins
Endotoxins
Lipopolysaccharides
Part of the outer membrane of the gram negative bacteria and freed only during bacterial lysis
Heat resistant
Cardinal manifestations of inflammation
Calor – heat
Tumor – swelling
Dolor – pain
Rubor - redness
Functio Laesa: Loss of function
Anti-septic
Process of inhibiting growth on living tissue
Thermal death point
Lowest temperature, all micro organisms will be killed in 10 minutes
Decimal reduction
Time it will take to kill 90% of microorganisms present
Thermal death time
Minimal time it takes to kill all micro organisms present
Innate/Nonspecific/Natural Immunity
A form of immunity due to physical characteristics that can be attributes to biological differences such as race or sex
Adaptive Immunity
The individual must either form antibodies to a pathogen personally or be given the antibodies from an alternate source
Natural Active Immunity
- Type of Adaptive Immunity
- Immunity as a result of developing a disease and recovering from it
Natural Passive Immunity
- Type of Adaptive Immunity
- Immunity as a result of placental transfer of antibodies in the uterus or from the transfer of antibodies in the mother’s milk
Artificial Active Immunity
- Type of Adaptive Immunity
- Immunity as a result of receiving a vaccination
Artificial Passive Immunity
- Type of Adaptive Immunity
- Immunity as a result of the injection of antibodies in the form of immune (convalescent) serums. Only provides short-term transient immunity (somewhat like a vaccine but with antibodies instead of a virus)
Antigen
- Antigens are foreign substances (a type of pathogen) that stimulate the formation of antibodies, which interact specifically with the antigen.
- A marker on every cell, including invading pathogens, by which the body recognizes unknown cells or disease-causing organisms
Antibodies
neutralize or destroy antigens; found in mucous secretions
