Microbiology
The study of microorganisms.
The scientific study of nature, life and action of microorganisms.
Contamination
The state of being soiled by contact with infectious organisms or other material.
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Microbiology
The study of microorganisms.
The scientific study of nature, life and action of microorganisms.
Contamination
The state of being soiled by contact with infectious organisms or other material.
Sterile Processing technicians must have a basic understanding of microbiology for 2 reasons:
They have a responsibility to protect patients from microorganisms in the healthcare environment.
The nature of their job duties places them and their co-workers in harm’s way for exposure to harmful microorganisms.
Microorganism facts
Cells are the basic units of all living organisms (plants, animals, protozoa and bacteria)
Cells are the smallest unit that can live, grow and reproduce
Cells differ in size and shape, but they all have:
A nucleus
Cytoplasm
A cell membrane
Bacterial cells differ from both plant and animal cells because they have no membrane to separate the nucleus from the cytoplasm
Protozoa
Microscopic, single-celled organisms with a membrane-bound nucleus that are found in most habitats worldwide.
What percentage is beneficial to our lives?
95%
Bad Microorganisms
Harmful microorganisms can cause infections when introduced into a body site where they are not normally found
Pathogens are a specific concern for CS professionals, as disease-causing organisms can reside on instruments and devices used in patient care, leading to healthcare-associated infections (HAI’s)
An estimated 1.7 million patients per year acquire an HAI and 98,000 of them (1 in 17) will die from it
Pathogen
Capable of causing disease (disease-causing microorganism)
Classification of Microorganisms
The 1st word in a microorganism’s name (always capitalized) is the genus(family) of the microorganism
The 2nd word is the specific name (species) of the organism
Microorganisms are identified and classified according to certain characteristics
Bacteria
Non-Bacteria
Viruses
Protozoa
Fungi
Prions
Characteristics of Bacteria
Bacteria are incredibly small and can only be seen with a microscope that can magnify at least 900 times.
Bacteria are measured by Microns and most of 1-2 microns in size
The most common ways to identify and classify bacteria are by:
Shape
Color change
Need for oxygen
Micron
1/25,000 of an inch or 1/1,000 of a millimeter
Need for oxygen: Aerobic
Requiring the presence of air or free oxygen
These bacteria require oxygen
May grow in liquids if the liquid has oxygen dissolved in it
Example’s
Clostridium
Staphylococcus
Need for oxygen: Anaerobic
Can live in the absence of atmospheric oxygen
These bacteria do NOT require oxygen
Cannot grow in an environment where oxygen is present
Example’s
C. Tetanus
C. Botulinum
Shapes of bacteria
Spherical
These bacteria are shaped like a circle or a sphere (coccus)
Examples: Staphylococcus aureus and Streptococci
Rod
These bacteria are shaped like rods or bricks (bacillus)
Examples: Pseudonomas aeruginosa and Enterobacteria
Spiral
These bacteria are shaped like spirals (spirilla)
Example: Helicobacter pylori
Endospores
Some bacteria can change into a different form called enodospores (spores) by developing a thick coat around the cell’s nucleus when conditions required for growth are not adequate
Spores can become infectious and produce toxins once inside the body
Bacillus anthracis causes anthrax(an infection)
The Clostridium species causes tetanus(lockjaw) and botulism (primary affects the nervous system; leading to muscle paralysis)
Spores are very resistant to disinfection and other conditions such as heat, making them very difficult to kill
Endospores(Spores)
Microorganisms capable of forming a thick wall around themselves enabling them to survive in adverse conditions; a resistant form of bacterium.
Color Change in Bacteria
Gram Positive +
These bacteria have no outer membrane and will retain the purple stain after treatment with iodine
Stains Purple
Examples:
Staphlyococcus aureus
Bacillus anthracis
Clostridium difficle (C.diff)
Gram Negative -
These bacteria have an outer membrane and will Not retain the purple stain after treatment with iodine
Stains Pink
Examples:
Pseudonomas aeruginosa
Escherichia coli (E.coli)
Klebsiella
Acid Fast (Ziehl-Neilson stain)
Acid fast bacteria are difficult to stain and may require heat or other agents to become stained
Once stained, the bacteria will resist color change
Examples:
M. Tuberculosis
M. Leprae
Conditions for bacteria growth
The suitable environments for bacteria can be broken down into:
Nutritional needs
Temperature
Moisture/humidity
pH
Light
Pathogenic bacteria are moat likely to thrive where their specific nutritional needs can be met
pH
Measure of alkalinity or acidity on a scale of 0 to 14
pH of 7 is neutral (neither acid nor alkaline)
pH above 7 is alkaline
Temperature requirements for bacteria
Bacteria pathogenic to humans prefer the moderate temperature range and are called Mesophiles.
Optimal temperature for growth
Cold temp: 59F to 68F
Moderate temp: 68F to 113F
Warm temp: 122F to 158F
Conditions of bacteria growth
Dark conditions are favorable to the growth of bacteria
Sunlight is lethal to organisms while they are actively growing
The most lethal light is ultraviolet (UV) light
Bacteria are transmitted primarily by:
Droplets
Contaminated water or food
Direct contact
Through wounds
Through the air
By disease-carrying animals
Vegetative stage
States of active growth of microorganisms (as opposed to resting or spore stages)
How bacteria grow
When optimal conditions are present, most bacteria and other microorganisms reproduce approximately every 20 minutes
Microorganisms reproduce in a process called binary fission through which the “mother” cells divides into 2 “daughter” cells
Binary Fission
The typical method of bacterial reproduction in which a cell divides into 2 equal parts
Multiple-Drug resistant organisms
Microorganisms can adapt and change as a means of survival
Multiple-Drug resistant organisms (MDRO) have become resistant to antibiotics used to treat bacteria infections and are increasingly found in healthcare facilities
Resistant pathogens can produce many types of infection in any body site
Common drug resistant bacteria: Methicillin-resistant Staphylococcus aureus (MRSA)
Lives on the skin and is known for causing severe infections
Spread by:
Direct contact with someone with the infection
Touching a contaminated surface
Common drug resistant bacteria: Vancomycin-resistant Enterococci (VRE)
Lives in the bowels
Transmitted when:
Hands become contaminated from feces, urine or blood that is infected
Touching a contaminated surface
Common drug resistant bacteria: Vancomycin-resistant Strephtococcus pneumonia
Lives asymptotically in the nose and pharynx of healthy carriers
Causes pneumonia
Spread by:
Direct contact with infected droplets from coughing or sneezing
Contact with other infected fluids
Common drug resistant bacteria: Klebisiella
Found on the hands and in the intestinal tract
Causes pneumonia, nasal infections, urinary tract, wound and bloodstream infections
Transferred from infected patients or surfaces through hand contact
Common drug resistant bacteria: Acinetobacter
Found normally in soil
Causes various illnesses ranging from pneumonia to serious blood or wound infections
Transmitted by person-to-person contact or by contact with contaminated surface
Common drug resistant bacteria: Carbapenum-resistant Enterobacteriaceae
A normal part of the human gut bacteria, including E. Coli
Infections associated with the use of devices such as endoscopes, ventilators, urinary or IV catheters
CRE infections are very difficult to treat and can contribute to death in up to 50% of patients who become infected
Common drug resistant bacteria: Pseudonomas aeruginosa
Frequently found in water and soil
Causes urinary tract, respiratory system, gastrointestinal, soft tissue and joint infections
These infections occur particularly in immunocompromised patients (severe burns, cancer, AIDS)
Transmitted through hand to hand contact or contact with contaminated surfaces