Microbiology

Microbiology

* The study of organisms too small to be seen without magnification
* Microorganisms include:

o viruses
o protozoa
o helminths (worms)

Branches of Study Within Microbiology


* Public health microbiology and epidemiology
* Food, dairy and aquatic microbiology
* Genetic engineering and recombinant DNA technology

Microbes are Involved in
* Nutrient production and energy flow
* Biotechnology
o production of foods, drugs and vaccines
* Bioremediation

Infectious Diseases
* Nearly 2,000 different microbes cause diseases.
* 10 Billion new infections/year worldwide
* 13 Million deaths from infections/year worldwide

Characteristics of Microbes

* Procaryotes and eukaryotes
o procaryote – microscopic, unicellular organisms, lack nuclei and membrane-bound organelles
o eucaryote – unicellular (microscopic) and multicellular, nucleus and membrane-bound organelles
* Viruses
o acellular, parasitic particles composed of a nucleic acid and protein

Basic cell and virus structures
Microbial Dimensions

* Procaryotes are measured in micrometers.
* Viruses in nanometers
* Helminths are measured in millimeters.

Historical Foundations of Microbiology
* 300 years of contributions by many
* Prominent discoveries include:
o microscopy
o scientific method
o development of medical microbiology
o microbiology techniques

Antonie van Leeuwenhoek

* Dutch linen merchant
* First to observe living microbes
* Single-lens magnified up to 300X

Spontaneous Generation
Early belief that some forms of life could arise from vital forces present in nonliving or decomposing matter (flies from manure, etc)
Scientific Method
* A general approach to explain a natural phenomenon
* Form a hypothesis - a tentative explanation that can be supported or refuted by observation and experimentation
* A lengthy process of experimentation, analysis and testing either supports or refutes the hypothesis.
* Results must be published and repeated by other investigators.
* If hypothesis is supported by a growing body of evidence and survives rigorous scrutiny, it moves to the next level of confidence - it becomes a theory.
* If evidence of a theory is so compelling that the next level of confidence is reached - it becomes a Law or principle.

Discovery of Spores and Sterilization

* John Tyndall and Ferdinand Cohn each demonstrated the presence of heat resistant forms of some microbes.
o Cohn determined these forms to be
* requires the elimination of all life forms including endospores and

Development of Aseptic Techniques

* Dr. Oliver Wendell – observed that mothers of home births had fewer infections than those who gave birth in hospital
* Dr. Ignaz – correlated infections with physicians coming directly from autopsy room to maternity ward
* Joseph – introduced aseptic techniques reducing microbes in medical settings to prevent infections
o involved disinfection of hands using chemicals prior to surgery
o use of heat for sterilization


Pathogens and Germ Theory of Disease

* Many diseases are caused by the growth of microbes in the body and not by sins, bad character, or poverty, etc.
* Two major contributors:

Louis Pasteur
* Showed microbes caused fermentation and spoilage
* Disproved spontaneous generation of microorganisms
* Developed pasteurization
* Demonstrated what is now known as Germ Theory of Disease
* Developed a rabies vaccine

Robert Koch

* Established Koch’s postulates - a sequence of experimental steps that verified the germ theory
* Identified cause of anthrax, TB, and cholera
* Developed pure culture methods

Taxonomy: Organizing, Classifying and Naming Living Things
* Formal system originated by Carl von Linné (1701-1778)

* Concerned with:
o classification – orderly arrangement of organisms into groups
o nomenclature – assigning names
o identification – discovering and recording traits of organisms for placement into taxonomic schemes

Levels of Classification
* Domain - Archaea, Bacteria & Eukarya
* Kingdom - 5
* Phylum or Division
* Class
* Order
* Family
* Genus
* species

Naming Micoorganisms

* Binomial (scientific) nomenclature
* Gives each microbe 2 names:
o Genus - noun, always capitalized
o species - adjective, lowercase
* Both italicized or underlined
o Staphylococcus aureus (S. aureus)
o Bacillus subtilis (B. subtilis)
o Escherichia coli (E. coli)

Evolution - living things change gradually over millions of years

* Changes favoring survival are retained and less beneficial changes are lost.
* All new species originate from preexisting species.
* Closely related organism have similar features because they evolved from common ancestral forms.
* Evolution usually progresses toward greater complexity.

* Bacteria - true bacteria, peptidoglycan
* Archaea - odd bacteria that live in extreme environments, high salt, heat, etc.
* Eukarya- have a nucleus and organelles

Woese-Fox System
Microbiology.ppt

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Aseptic techniques for bacteria culture

Aseptic techniques for bacteria culture

Aseptic techniques and media used for bacteria culture

Using sterile techniques

* Bacteria are everywhere
* Media used for bacteria growth - welcoming for many bacteria
* We only want specific ones to grow
* Sterile remain sterile as long as doesn’t touch anything that isn’t sterile
* Also avoid prolonged exposure to air

Sterile techniques: what can you do in the lab?
* Wash your hands
* Keep your bench clean
* Wear gloves
* Flame loop, neck of tube
* Keep cap facing down
* Work quickly albeit efficiently
* Limit talking when opening cultures

Autoclaving

* Apparatus used to sterilize liquid and instrument
* Heating up to 121oC at 15 psi for 15 minutes
* Kill most microbe
* Autoclave tape - chemical reaction - black stripes if autoclaving ok

Culture media
Bacteria colonies
Composition of media

* NA = Nutrient Agar
o peptone, beef extract, salt, agar 1.5%
* TSA = Tryptic soy agar
o Peptone from casein, peptone from soymeal, sodium chloride, agar 1.5%
* Many other medias available. These 2 will be used very often in this lab
* Note: Peptone: enzymatic digest protein

Few notes on agar

* Not degraded by most bacteria
* Is liquified at 100oC and remain liquid until about 40oC
* If added to growth medium - medium becomes solid
* Semi solid media: 0.5% agar
* Broth: no agar
* Solid media: 1.5-3% agar

How to prepare a Petri plate

* Take liquid agar (in the water bath)
* Pour aseptically into the base of the Petri plate (top is larger than the base)
* Wait until solidify (15 minutes) - invert
* ***Plates are kept inverted so condensation does not drip onto the agar

Pouring a plate
Objective : Cultivate bacteria sample from the environment
How to inoculate a plate
Colonial morphology
Description
How to open a tube
How to inoculate a deep
Bacteria motility
Oxygen requirement
Deep observation
How to inoculate a slant
Slant observation
How to inoculate a broth
Broth observation
Uses
Synthesis

* Cultivate a bacterial sample from the environment. Incubate 27o C
* Inoculate the pure culture provided
o Into a broth
o Into a slant
o Into a deep
o Into a Petri plate
o *** Using aseptic techniques ***Put all the above in the 37oC incubator
* Describe colonial morphology from a Petri plate and a slant
* Identify growth pattern in broth and deep


Aseptic techniques for bacteria culture.ppt

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Care of the Client with Diabetes

Care of the Client with Diabetes
Presentation lecture by:Christie M. Candelaria, MA, RN, CCRN.

DIABETES MELLITUS

* Caused by a relative deficit of insulin secretion from the beta cells in the islets of Langerhans or by a lack of response by cells to insulin (insulin resistance)
* Deficient insulin results in abnormal carbohydrate, protein, and fat metabolism due to impaired transport of glucose and amino acids into the cells

Types of Diabetes

* Type I
* Type 2
* Gestational
* Other types include:
o Genetic defect beta cell or insulin
o Disease of exocrine pancreas
o Drug or chemical induced
o Infections
o Others

Pathophysiology: INITIAL STAGE
* Insulin deficit leads to:
o Decreased transportation and use of glucose in many cells of the body
o Blood glucose levels rise (hyperglycemia)
o Excess glucose spills into the urine (glucosuria)
o Glucose in the urine exerts osmotic pressure in the filtrate, resulting in large volume of urine to be excreted (polyuria) with loss of fluids and electrolytes from the body tissues
o Fluid loss through the urine and high blood glucose levels draw water from the cells, resulting in dehydration
o Dehydration causes thirst (polydipsia)
o Lack of nutrients entering the cells stimulates appetite (polyphagia)

PROGRESSIVE EFFECTS

* Lack of glucose in cells results in catabolism of fats and proteins, leading to excessive amounts of fatty acids and their metabolites known as ketones or ketoacids in the blood.
* Some ketoacids are excreted in the urine (ketonuria)

Acute Complications of Diabetes
* Diabetic ketoacidosis
* Hyperglycemic-hyperosmolar-nonketotic syndrome
* Hypoglycemia from too much insulin or too little glucose

Chronic Complications of Diabetes
* Macrovascular complications
o Cardiovascular disease
o Cerebrovascular disease
o Peripheral vascular disease
* Microvascular complications
o Retinopathy (vision) problems
o Diabetic neuropathy
o Diabetic nephropathy
o Male erectile dysfunction
Assessment
* History
* Blood tests
o Fasting blood glucose test: two tests > 126 mg/dL
o Oral glucose tolerance test: blood glucose > 200 mg/dL at 120 minutes
o Glycosylated hemoglobin assays
o Glucosylated serum proteins and albumin

Urine Tests
* Urine testing for ketones
* Urine testing for renal function
* Urine testing for glucose

Drug Therapy
Goal: tight glycemic control
* Drug administration
* Drug selection
* Insulin therapy:
o Insulin analogue
o Short-acting insulin
o Concentrated insulin
o Intermediate
Oral Blood Glucose Lowering Agents

Sulfonylureas

* Appropriate only for clients with pancreatic beta cell function
* Most common serious complication: hypoglycemia
* Side Effects: hematologic reactions
o Allergic skin reactions
o Gastrointestinal effects

Meglitinides
* Repaglinide (Prandin)
* Action and side effects similar to sulfonylureas: hypoglycemia
o GI disturbances
o UR infections
o Arthralgia
o Back pain
o headache

Biguanides

* Metformin (glucophage)
* The only biguanide available in the USA
* Can cause lactic acidosis in clients with renal insufficiency

Alpha-glucosidase inhibitors

* Acarbose (Precose)
* Reduce postprandial hyperglycemia by slowing digestion and absorption of carbohydrate within the intestine
* Side effects: abdominal discomfort related to undigested carbohydrate in the intestinal tract

Thiazolidinedione antidiabetic agents
* Troglitazone
* Enhance insulin action, promoting glucose utilization in peripheral tissues
* Liver function studies should be done at the start of therapy and at regular intervals during therapy

Combination agents
* Combinations from two different classes of medications
* E.g: Glucovance

What’s New

* DDP-4 inhibitors – help lower blood glucose levels by increasing and prolonging the action of GLP-1
o Also called “incretin enhancers”
o How does it work:

When we eat, GLP-1 (glucagonlike peptide-1) is released by the small intestine in response to ingested carbohydrates which

1. helps regulate the synthesis and release of insulin from the pancreatic beta cells
2. initiates neuropeptide reactions that reduce hepatic glucose (glucagon) production after meals
3. induce satiety by crossing the blood-brain barrier to reduce appetite
4. slows down gastric emptying
5. may also play a role in beta-cell regrowth and repair known as its “pancreatic-sparing effect”
* Sitagliptin (Januvia) – first in the market
o Can be used alone or in combination with other oral medications like metformin or thiazolidinediones
o Available in 25 mg, 50 mg, 100 mg tabs.
o Typically administered as a 100-mg dose once daily with or without food; can be titrated down depending on patient’s renal status
o Weight-neutral drug; neither promoting weight loss or weight gain
o Approved only for adults
o Adverse reactions: URTI, nasopharyngitis, diarrhea, headache
* Vildagliptin (Galvus) – in the final stages of FDA approval

Insulin Regimens

* Single daily injection protocol
* Two-dose protocol
* Three-dose protocol
* Four-dose protocol
* Combination therapy
* Intensified therapy regimens

Drug Therapy

o Fixed-combination
o Long-acting
o Buffered insulins

Complications of Insulin Therapy

* Hypoglycemia
* Lipoatrophy
* Dawn phenomenon
* Somogyi's phenomenon

Alternative Methods of Insulin Administration

* Continuous subcutaneous infusion of insulin
* Implanted insulin pumps
* Injection devices
* New technology includes:
o Inhaled insulin
o Transdermal patch (being tested)

Client Education

* Storage and dose preparation
* Syringes
* Blood glucose monitoring
* Interpretation of results
* Frequency of testing
* Blood glucose therapy goals

Diet Therapy
* Goals of diet therapy
* Principles of nutrition in diabetes
o Protein, fats and carbohydrates, fiber, sweeteners, fat replacers
o Alcohol
o Food labeling
o Exchange system, carbohydrate counting
o Special considerations for type 1 and type 2 diabetes

Exercise Therapy

* Benefits of exercise
* Risks related to exercise
* Screening before starting exercise program
* Guidelines for exercise
* Exercise promotion

Whole-Pancreas Transplantation
* Operative procedure
* Rejection management
* Long-term effects
* Complications
* Islet cell transplantation hindered by limited supply of beta cells and problems caused by antirejection drugs

Nursing Diagnoses
Risk for Injury Related to Sensory Alterations
* Interventions and foot care practices:
o Cleanse and inspect the feet daily.
o Wear properly fitting shoes.
o Avoid walking barefoot.
o Trim toenails properly.
o Report nonhealing breaks in the skin.

Wound Care

* Wound environment
* Debridement
* Elimination of pressure on infected area
* Growth factors applied to wounds

Chronic Pain

* Interventions include:
o Maintenance of normal blood glucose levels
o Anticonvulsants
o Antidepressants
o Capsaicin cream

Risk for Injury Related to Disturbed Sensory Perception: Visual
* Interventions include:
o Blood glucose control
o Environmental management
+ Incandescent lamp
+ Coding objects
+ Syringes with magnifiers
+ Use of adaptive devices

Ineffective Tissue Perfusion: Renal
* Interventions include:
o Control of blood glucose levels
o Yearly evaluation of kidney function
o Control of blood pressure levels
o Prompt treatment of UTIs
o Avoidance of nephrotoxic drugs
o Diet therapy
o Fluid and electrolyte management

Potential for Hypoglycemia

* Blood glucose level < 70 mg/dL
* Diet therapy: carbohydrate replacement
* Drug therapy: glucagon, 50% dextrose, diazoxide, octreotide
* Prevention strategies for:
o Insulin excess
o Deficient food intake
o Exercise
o Alcohol

Potential for Diabetic Ketoacidosis
* Interventions include:
o Monitoring for manifestations
o Assessment of airway, level of consciousness, hydration status, blood glucose level
o Management of fluid and electrolytes
o Drug therapy goal: to lower serum glucose by 75 to 150 mg/dL/hr
o Management of acidosis
o Client education and prevention

Potential for Hyperglycemic-Hyperosmolar Nonketotic Syndrome and Coma

* Interventions include:
o Monitoring
o Fluid therapy: to rehydrate the client and restore normal blood glucose levels within 36 to 72 hr
o Continuing therapy with IV regular insulin at 10 units/hr often needed to reduce blood glucose levels


Health Teaching

* Assessing learning needs
* Assessing physical, cognitive, and emotional limitations
* Explaining survival skills
* Counseling
* Psychosocial preparation
* Home care management
* Health care resources

Care of the Client with Diabetes.ppt

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