Provides some inputs about microbial control. This will help to appreciate the importance of sanitation to protect us from any potential diseases. In this situation, wherein we are facing the crisis caused by COVID-19 or SARS-Ncov-2, this will really help to mitigate and contain the virus.
At the end of this session learner will be able to:
Define Common terms.
Explain the importance of microorganisms control.
Discuss the Methods of sterilization.
Categorize the broad spectrum and narrow spectrum antibiotics.
At the end of this session learner will be able to:
Define Common terms.
Explain the importance of microorganisms control.
Discuss the Methods of sterilization.
Categorize the broad spectrum and narrow spectrum antibiotics.
Control of microorganism ppt
physical method Control of microbes
chemical method Control of microbes
types of Control of microbes
pasteurization Control of microbes
sterilization
disinfection
sanitization
Killing or removing all forms of microbial life (including endospores) in a material or an object.
Mainly due to: oxidation of cell component, denature proteins, nucleic acids, RNA and loss of membrane permeability.
Procedures performed in a way to prevent contamination with infectious microorganisms
Used to prevent contamination of surgical instruments, medical personnel, and the patient during surgery
Sanitization: Lowering of microbial counts to prevent transmission in public setting (e.g., restaurants & public rest rooms)
Degerming: Mechanical removal of microbes from limited area. e.g., Alcohol swab on skin, washing of hands with soap
Sepsis: Bacterial contamination
Antisepsis: Reduction or Inhibition of microbes found on LIVING TISSUE
Control of microorganism ppt
physical method Control of microbes
chemical method Control of microbes
types of Control of microbes
pasteurization Control of microbes
sterilization
disinfection
sanitization
Killing or removing all forms of microbial life (including endospores) in a material or an object.
Mainly due to: oxidation of cell component, denature proteins, nucleic acids, RNA and loss of membrane permeability.
Procedures performed in a way to prevent contamination with infectious microorganisms
Used to prevent contamination of surgical instruments, medical personnel, and the patient during surgery
Sanitization: Lowering of microbial counts to prevent transmission in public setting (e.g., restaurants & public rest rooms)
Degerming: Mechanical removal of microbes from limited area. e.g., Alcohol swab on skin, washing of hands with soap
Sepsis: Bacterial contamination
Antisepsis: Reduction or Inhibition of microbes found on LIVING TISSUE
Sterilization (or sterilisation) referring to any process that eliminates (removes) or kills (deactivates) all forms of life and other biological agents (such as prions, as well as viruses which some do not consider to be alive but are biological pathogens nonetheless), including transmissible agents (such as fungi, bacteria, viruses, prions, spore forms, unicellular eukaryotic organisms such as Plasmodium, etc.) present in a specified region, such as a surface, a volume of fluid, medication, or in a compound such as biological culture media
This powerpoint describes about sterilization which is a basic technique applied by life science members who are performing microbiological, molecular biology, genetic engineering, recombinant DNA technology, molecular genetics techniques and also this process in performed in health care sectors to prevail aseptic conditions,
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Ve...kevinkariuki227
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
TEST BANK for Operations Management, 14th Edition by William J. Stevenson, Verified Chapters 1 - 19, Complete Newest Version.pdf
These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
3. The Selection of Microbial Control Methods
• Factors Affecting the Efficacy of
Antimicrobial Methods
▫ Site to be treated
Harsh chemicals and extreme heat cannot be used on
humans, animals, and fragile objects
Method of microbial control based on site of medical
procedure
3
5. The Selection of Microbial Control Methods
• Factors Affecting the Efficacy of
Antimicrobial Methods
▫ Relative susceptibility of microorganisms
Germicides classified as high, intermediate, or low
effectiveness
High-level kill all pathogens, including endospores
Intermediate-level kill fungal spores, protozoan cysts,
viruses, and pathogenic bacteria
Low-level kill vegetative bacteria, fungi, protozoa, and
some viruses
5
7. The Selection of Microbial Control Methods
• Methods for Evaluating Disinfectants and
Antiseptics
▫ Phenol coefficient
Evaluates efficacy of disinfectants and antiseptics by
comparing an agent’s ability to control microbes to
phenol
Greater than 1.0 indicates agent is more effective
than phenol
Has been replaced by newer methods
7
8. The Selection of Microbial Control Methods
• Methods for Evaluating Disinfectants and Antiseptics
– Use-dilution test
• Metal cylinders dipped into broth cultures of bacteria
• Contaminated cylinder immersed into dilution of
disinfectant
• Cylinders removed and placed into tube of medium to see
how much bacteria survived
• Most effective agents entirely prevent growth at highest
dilution
• Current standard test in the U.S.
• New standard procedure being developed
8
9. The Selection of Microbial Control Methods
• Methods for Evaluating Disinfectants and
Antiseptics
▫ Kelsey-Sykes capacity test
Alternative assessment approved by the
European Union
Bacterial suspensions added to the chemical
being tested
Samples removed at predetermined times and
incubated
Lack of bacterial reproduction reveals minimum
time required for the disinfectant to be effective
9
10. The Selection of Microbial Control Methods
• Methods for Evaluating Disinfectants and
Antiseptics
▫ In-use test
Swabs taken from objects before and after
application of disinfectant or antiseptic
Swabs inoculated into growth medium and
incubated
Medium monitored for growth
Accurate determination of proper strength and
application procedure for each specific situation
10
11. Physical Methods of Microbial Control
• Heat-Related Methods
▫ Effects of high temperatures
Denature proteins
Interfere with integrity of cytoplasmic membrane
and cell wall
Disrupt structure and function of nucleic acids
▫ Thermal death point
Lowest temperature that kills all cells in broth in 10
min
▫ Thermal death time
Time to sterilize volume of liquid at set temperature
11
12. Physical Methods of Microbial Control
• Heat-Related Methods
▫ Moist heat
Used to disinfect (kill organisms and remove spores),
sanitize (kill organisms but not necessarily their spores),
and sterilize (kill all organisms and spores)
Denatures proteins and destroys cytoplasmic membranes
More effective than dry heat
Methods of microbial control using moist heat
Boiling
Autoclaving
Pasteurization
Ultrahigh-temperature sterilization
12
13. Physical Methods of Microbial Control
• Heat-Related Methods
▫ Moist heat
Boiling
Kills vegetative cells of bacteria and fungi, protozoan
trophozoites, and most viruses
Boiling time is critical
▫ Different elevations require different boiling times
Endospores, protozoan cysts, and some viruses can
survive boiling
13
14. Physical Methods of Microbial Control
• Heat-Related Methods
▫ Moist heat
Autoclaving
Pressure applied to boiling water prevents steam from
escaping
Boiling temperature increases as pressure increases
Autoclave conditions – 121ºC, 15 psi, 15 min
14
17. Physical Methods of Microbial Control
• Heat-Related Methods
▫ Moist heat
Pasteurization
Used for milk, ice cream, yogurt, and fruit juices
Not sterilization
▫ Heat-tolerant microbes survive
Pasteurization of milk
▫ Batch method
▫ Flash pasteurization (High temp, short time)
▫ Ultrahigh-temperature pasteurization (very high temp,
very short time)
17
18. Pasteurization of milk
Batch method
• The batch method uses a vat pasteurizer which consists
of a jacketed vat surrounded by either circulating water,
steam or heating coils of water or steam.
In the vat the milk is heated and
held throughout the holding period
while being agitated. The milk may
be cooled in the vat or removed hot
after the holding time is completed
for every particle.
18
19. Pasteurization of milk
Flash method
• High Temperature Short Time (HTST)
• Milk is heated to 72°C (161.6°F) for at least 15 seconds.
• Used for perishable beverages like fruit and vegetable
juices, beer, and some dairy products. Compared to
other pasteurization processes, it maintains color and
flavor better.
• It is done prior to filling into containers in order to kill
spoilage microorganisms, to make the products safer and
extend their shelf life. Flash pasteurization must be used
in conjunction with sterile fill technology.
19
20. Pasteurization of milk
Ultrahigh-temperature method
• Heating for 1-2 seconds at a temperature exceeding
135°C (275°F), which is the temperature required to kill
spores in milk.
• The most common UHT product is milk, but the process
is also used for fruit juices, cream, soy milk, yogurt,
wine, soups, and stews.
• Can cause browning and change the taste and smell of
dairy products.
• UHT canned milk has a typical shelf life of six to nine
months, until opened.
20
21. Physical Methods of Microbial Control
• Heat-Related Methods
▫ Moist heat
Ultrahigh-temperature sterilization
140ºC for 1 sec, then rapid cooling
Treated liquids can be stored at room temperature
21
22. Physical Methods of Microbial Control
• Heat-Related Methods
▫ Dry heat
Used for materials that cannot be sterilized with
moist heat
Denatures proteins and oxidizes metabolic and
structural chemicals
Requires higher temperatures for longer time than
moist heat
Incineration is ultimate means of sterilization
22
23. Physical Methods of Microbial Control
• Refrigeration and Freezing
▫ Decrease microbial metabolism, growth, and
reproduction
Chemical reactions occur slower at low temperatures
Liquid water not available
▫ Psychrophilic microbes can multiply in
refrigerated foods
▫ Refrigeration halts growth of most pathogens
▫ Slow freezing more effective than quick freezing
▫ Organisms vary in susceptibility to freezing
23
24. Physical Methods of Microbial Control
• Dessication and Lyophilization
▫ Dessication is drying (98% of the water is
removed) inhibits growth due to removal of water
▫ Lyophilization (freeze-drying)
Substance is rapidly frozen and sealed in a vacuum
Substance may also be turned into a powder
▫ Used for long-term preservation of microbial
cultures
Prevents formation of damaging ice crystals
24
25. The use of dessication as a means of preserving
apricots
Figure 9.8
25
27. The role of HEPA filters in biological safety cabinets
Figure 9.10
High-Efficiency Particulate
Arresting (HEPA) air filters are
used in medical facilities,
automobiles, aircraft, and
homes. The filter must remove
99.97% of all particles greater
than 0.3 micrometer from the
air that passes through.
27
28. Physical Methods of Microbial Control
• Osmotic Pressure
▫ High concentrations of salt or sugar in foods to
inhibit growth
▫ Cells in hypertonic solution of salt or sugar lose
water
▫ Fungi have greater ability than bacteria to survive
hypertonic environments
28
29. Physical Methods of Microbial Control
• Radiation
▫ Ionizing radiation
Wavelengths shorter than 1 nm
Electron beams, gamma rays
Ejects electrons from atoms to create ions
Ions disrupt hydrogen bonding, cause oxidation, and
create hydroxide ions
Hydroxide ions denature other molecules (DNA)
Electron beams – effective at killing but do not
penetrate well
Gamma rays – penetrate well but require hours to kill
microbes
29
32. Physical Methods of Microbial Control
• Radiation
▫ Nonionizing radiation
Wavelengths greater than 1 nm
Excites electrons, causing them to make new covalent
bonds
Affects 3-D structure of proteins and nucleic acids
UV light causes pyrimidine dimers in DNA
UV light does not penetrate well
Suitable for disinfecting air, transparent fluids, and
surfaces of objects
32
33. Physical Methods of Microbial Control
• Biosafety Levels
▫ Four levels of safety in labs dealing with
pathogens
Biosafety Level 1 (BSL-1)
Handling pathogens that do not cause disease in
healthy humans
Biosafety Level 2 (BSL-2)
Handling of moderately hazardous agents
Biosafety Level 3 (BSL-3)
Handling of microbes in safety cabinets
Biosafety Level 4 (BSL-4)
Handling of microbes that cause severe or fatal disease
33
35. Chemical Methods of Microbial Control
• Affect microbes’ cell walls, cytoplasmic
membranes, proteins, or DNA
• Effect varies with differing environmental
conditions
• Often more effective against enveloped viruses
and vegetative cells of bacteria, fungi, and
protozoa
35
36. Chemical Methods of Microbial Control
• Phenol and Phenolics
▫ Intermediate- to low-level disinfectants
▫ Denature proteins and disrupt cell membranes
▫ Effective in presence of organic matter
▫ Remain active for prolonged time
▫ Commonly used in health care settings, labs, and
homes
▫ Have disagreeable odor and possible side effects
36
37. Chemical Methods of Microbial Control
• Alcohols
▫ Intermediate-level disinfectants
▫ Denature proteins and disrupt cytoplasmic
membranes
▫ More effective than soap in removing bacteria
from hands
▫ Swabbing of skin with 70% ethanol prior to
injection
37
38. Chemical Methods of Microbial Control
• Halogens
▫ Intermediate-level antimicrobial chemicals
▫ Believed to damage enzymes via oxidation or by
denaturation
▫ Widely used in numerous applications
Iodine tablets, iodophores, chlorine treatment,
bleach, chloramines, and bromine disinfection
38
41. Chemical Methods of Microbial Control
• Oxidizing Agents
▫ Peroxides, ozone, and peracetic acid
▫ Kill by oxidation of microbial enzymes
▫ High-level disinfectants and antiseptics
▫ Hydrogen peroxide (H2O2) can disinfect and
sterilize surfaces
Not useful for treating open wounds due to catalase
activity: the tissues convert it into H20 and 0ygen
bubbles.
▫ Ozone treatment of drinking water
▫ Peracetic acid is an effective sporocide used to
sterilize equipment
41
42. Chemical Methods of Microbial Control
• Surfactants
▫ “Surface active” chemicals
Reduce surface tension of solvents
▫ Soaps and detergents
Soaps have hydrophilic and hydrophobic ends
Good degerming agents but not antimicrobial
Detergents are positively charged organic surfactants
▫ Quats (Quaternary ammonium cations)
Low-level disinfectants; disrupts cell membranes
Ideal for many medical and industrial applications
Good against fungi, amoeba, and enveloped viruses,
but not endospores, Mycobacterium tuberculosis and
non-enveloped viruses.
42
43. Chemical Methods of Microbial Control
• Heavy Metals
▫ Heavy-metal ions denature proteins
▫ Low-level bacteriostatic and fungistatic agents
▫ 1% silver nitrate to prevent blindness caused by N.
gonorrhoeae
▫ Thimerosal used to preserve vaccines
▫ Copper inhibits algal growth
43
44. Chemical Methods of Microbial Control
• Aldehydes
▫ Compounds containing terminal –CHO groups
▫ Cross-link functional groups to denature proteins
and inactivate nucleic acids
▫ Glutaraldehyde disinfects and sterilizes
▫ Formalin used in embalming and disinfection of
rooms and instruments
44
45. Chemical Methods of Microbial Control
• Gaseous Agents
▫ Microbicidal and sporicidal gases used in closed
chambers to sterilize items
▫ Denature proteins and DNA by cross-linking
functional groups
▫ Used in hospitals and dental offices
▫ Disadvantages
Can be hazardous to people
Often highly explosive
Extremely poisonous
Potentially carcinogenic
45
46. Chemical Methods of Microbial Control
• Enzymes
▫ Antimicrobial enzymes act against microorganisms
▫ Human tears contain lysozyme
Digests peptidoglycan cell wall of bacteria
▫ Enzymes to control microbes in the environment
Lysozyme used to reduce the number of bacteria in
cheese
Prionzyme can remove prions on medical
instruments
46
47. Chemical Methods of Microbial Control
• Antimicrobials
▫ Antibiotics, semi-synthetic, and synthetic
chemicals
▫ Typically used for treatment of disease
▫ Some used for antimicrobial control outside the
body
47
48. Chemical Methods of Microbial Control
• Development of Resistant Microbes
▫ Little evidence that products containing antiseptic
and disinfecting chemicals is beneficial to human
or animal health
▫ Use of such products promotes development of
resistant microbes
48
49. Antimicrobial Agents
• Chemicals that affect physiology in any manner
• Chemotherapeutic agents
▫ Drugs that act against diseases
• Antimicrobial agents
▫ Drugs that treat infections
49
50. The History of Antimicrobial Agents
• Semi-synthetics
▫ Chemically altered antibiotics that are more
effective than naturally occurring ones
• Synthetics
▫ Antimicrobials that are completely synthesized in
a lab
50
51. Mechanisms of Antimicrobial Action
• Key is selective toxicity
• Antibacterial drugs constitute largest number
and diversity of antimicrobial agents
• Fewer drugs to treat eukaryotic infections
(protozoa, fungi, helminthes)
• Even fewer antiviral drugs
51
52. Mechanisms of Antimicrobial
Action
• Inhibition of bacterial wall synthesis
• Disruption of existing cytoplasmic membranes
• Inhibition of Protein Synthesis
• Inhibition of Nucleic Acid Synthesis
• Inhibition of Metabolic Pathways
• Prevention of Virus Attachment
52
53. Basic Principles of Microbial Control
• Action of Antimicrobial Agents
▫ Alteration of cell walls and membranes
Cell wall maintains integrity of cell
Cells burst due to osmotic effects when damaged
Cytoplasmic membrane controls passage of
chemicals into and out of cell
Cellular contents leak out when damaged
Non-enveloped viruses have greater tolerance of
harsh conditions
53
54. Mechanisms of Antimicrobial Action
• Inhibition of Cell Wall Synthesis
▫ Inhibition of bacterial wall synthesis
Most common agents prevent cross-linkage of NAM-
NAG subunits
Beta-lactams are most prominent in this group
Functional groups are beta-lactam rings
Beta-lactams bind to enzymes that cross-link NAM-
NAG subunits
Bacteria have weakened cell walls and eventually lyse
54
55. Mechanisms of Antimicrobial Action
• Inhibition of Cell Wall Synthesis
▫ Inhibition of synthesis of bacterial walls
Semi-synthetic derivatives of beta-lactams
More stable in acidic environments
More readily absorbed
Less susceptible to deactivation
More active against more types of bacteria
Simplest beta-lactams – effective only against
aerobic Gram-negatives
55
56. Mechanisms of Antimicrobial Action
• Inhibition of Cell Wall Synthesis
▫ Inhibition of synthesis of bacterial walls
Vancomycin and cycloserine
Interfere with particular bridges that link NAM
subunits in many Gram-positives
Bacitracin
Blocks secretion of NAG and NAM from cytoplasm
Effective against Gram positives
Isoniazid and ethambutol
Disrupt mycolic acid formation in mycobacterial
species
56
57. Mechanisms of Antimicrobial Action
• Inhibition of Cell Wall Synthesis
▫ Inhibition of synthesis of bacterial walls
Prevent bacteria from increasing amount of
peptidoglycan
Have no effect on existing peptidoglycan layer
Effective only for growing cells
57
58. Mechanisms of Antimicrobial Action
• Disruption of Cytoplasmic Membranes
▫ Some drugs form channels through cytoplasmic
membrane and damage its integrity
▫ Amphotericin B attaches to ergosterol in fungal
membranes
Humans somewhat susceptible because cholesterol
similar to ergosterol
Bacteria lack sterols; not susceptible
58
59. Mechanisms of Antimicrobial Action
• Disruption of Cytoplasmic Membranes
▫ Azoles and allyamines inhibit ergosterol synthesis
▫ Polymyxin disrupts cytoplasmic membranes of
Gram-negatives
Oral form is toxic to human kidneys, so only used
topically
▫ Some parasitic drugs act against cytoplasmic
membranes
59
60. Which topical ointment is best?
• Neomycin is an aminoglycoside antibiotic (disrupts protein synthesis). It
has excellent activity against Gram-negative bacteria, and has
partial activity against Gram-positive bacteria.
• Polymixin disrupts bacterial cell membranes by interacting with its
phospholipids. They are selectively toxic for Gram-negative bacteria.
• Bacitracin disrupts cell wall synthesis. Its action is on Gram-positive
organisms. It can cause contact dermatitis and cross-reacts with allergic
sensitivity to sulfa-drugs.
• Which topical ointment is best: Neomycin or Triple Antibiotic (contains all
three)
60
61. Basic Principles of Microbial Control
• Action of Antimicrobial Agents
▫ Damage to proteins and nucleic acids
Protein function depends on 3-D shape
Extreme heat or certain chemicals denature proteins
Chemicals, radiation, and heat can alter or destroy
nucleic acids
Can produce fatal mutants
Can halt protein synthesis through action on RNA
61
62. Mechanisms of Antimicrobial Action
• Inhibition of Protein Synthesis
▫ Prokaryotic ribosomes are 70S (30S and 50S)
▫ Eukaryotic ribosomes are 80S (40S and 60S)
▫ Drugs can selectively target translation
▫ Mitochondria of animals and humans contain 70S
ribosomes
Can be harmful
62
63. Mechanisms of Antimicrobial Action
• Inhibition of Protein Synthesis
▫ Aminoglycosides: excellent against Gram negatives,
partially effective against Gram positives
amikacin (Amikin®)
gentamicin (Garamycin®)
kanamycin (Kantrex®)
neomycin (Mycifradin®)
streptomycin
tobramycin (TOBI Solution®, TobraDex®)
63
65. Mechanisms of Antimicrobial Action
• Inhibition of Nucleic Acid Synthesis
▫ Several drugs block DNA replication or mRNA
transcription
▫ Drugs often affect both eukaryotic and prokaryotic
cells
▫ Not normally used to treat infections
▫ Used in research and perhaps to slow cancer cell
replication
65
67. Acyclovir
• Acyclovir is used to decrease pain and speed the healing of herpes sores or
blisters in people who have varicella (chickenpox), herpes zoster (shingles;
a rash that can occur in people who have had chickenpox in the past), and
first-time or repeat outbreaks of genital herpes (a herpes virus infection
that causes sores to form around the genitals and rectum from time to
time).
• Acyclovir is also sometimes used to prevent outbreaks of herpes sores in
people who are infected with the virus.
• Acyclovir disrupts nucleic acid function. It works by stopping the spread of
the herpes virus in the body. Acyclovir will not cure herpes or protect others
from catching it.
67
68. Mechanisms of Antimicrobial Action
• Inhibition of Nucleic Acid Synthesis
▫ Quinolones and fluoroquinolones
Act against prokaryotic DNA gyrase (enzyme that is
needed for DNA to unwind during replication)
▫ Inhibitors of RNA polymerase (enzyme used
during transcription)
▫ Reverse transcriptase inhibitors
Act against an enzyme HIV uses in its replication
cycle
Does not harm people because humans lack reverse
transcriptase
68
69. Mechanisms of Antimicrobial Action
• Inhibition of Nucleic Acid Synthesis
▫ Nucleotide analogs
Interfere with function of nucleic acids
Distort shapes of nucleic acid molecules and prevent
further replication, transcription, or translation
Most often used against viruses
Effective against rapidly dividing cancer cells
69
71. Mechanisms of Antimicrobial Action
• Inhibition of Metabolic Pathways
▫ Antimetabolic agents can be effective when
pathogen and host metabolic processes differ
▫ Quinolones interfere with the metabolism of
malaria parasites
▫ Heavy metals inactivate enzymes
▫ Some agents disrupt glucose uptake by many
protozoa and parasitic worms
▫ Some drugs block activation of viruses
71
72. Mechanisms of Antimicrobial Action
• Inhibition of Metabolic Pathways
▫ Antiviral agents can target unique aspects of viral
metabolism
Amantadine, rimantadine, and weak organic bases
prevent viral uncoating
▫ Protease inhibitors interfere with an enzyme that
HIV needs in its replication cycle
72
73. Mechanisms of Antimicrobial Action
• Prevention of Virus Attachment
▫ Attachment antagonists block viral attachment or
receptor proteins
▫ New area of antimicrobial drug development
73
74. Clinical Considerations in Prescribing
Antimicrobial Drugs
• Ideal Antimicrobial Agent
▫ Readily available
▫ Inexpensive
▫ Fast-acting
▫ Chemically stable during storage
▫ Easily administered
▫ Nontoxic and nonallergenic
▫ Selectively toxic against wide range of pathogens
▫ Capable of controlling microbial growth while being harmless
to humans, animals, and objects
74
75. Clinical Considerations in Prescribing
Antimicrobial Drugs
• Spectrum of Action
▫ Number of different pathogens a drug acts against
Narrow-spectrum effective against few organisms
(Gram positive bacteria only)
Broad-spectrum effective against many organisms
(Gram positive and Gram negative bacteria)
May allow for secondary or superinfections to develop
Killing of normal flora reduces microbial antagonism
75
81. Clinical Considerations in Prescribing
Antimicrobial Drugs
• Routes of Administration
▫ Topical application of drug for external infections
▫ Oral route requires no needles and is self-
administered
▫ Intramuscular (IM) administration delivers drug
via needle into muscle
▫ Intravenous (IV) administration delivers drug
directly to bloodstream
▫ Must know how antimicrobial agent will be
distributed to infected tissues
81
82. Effect of route of
administration on
chemotherapeutic
agent
Figure 10.13
82
83. Clinical Considerations in Prescribing
Antimicrobial Drugs
• Safety and Side Effects
▫ Toxicity
Cause of many adverse reactions poorly understood
Drugs may be toxic to kidneys, liver, or nerves
Consideration needed when prescribing drugs to
pregnant women
▫ Allergies
Allergic reactions are rare but may be life
threatening
Anaphylactic shock
83
85. Clinical Considerations in Prescribing
Antimicrobial Drugs
• Safety and Side Effects
▫ Disruption of normal microbiota
May result in secondary infections
Overgrowth of normal flora causing superinfections
Of greatest concern for hospitalized patients
85
86. Resistance to Antimicrobial Drugs
• The Development of Resistance in
Populations
▫ Some pathogens are naturally resistant
▫ Resistance by bacteria acquired in two ways
New mutations of chromosomal genes
Acquisition of resistance genes (R-plasmids) via
transformation, transduction, and conjugation
86
88. Resistance to Antimicrobial Drugs
• Mechanisms of Resistance
▫ At least six mechanisms of microbial resistance
Production of enzyme that destroys or deactivates
drug
Slow or prevent entry of drug into the cell
Alter target of drug so it binds less effectively
Alter their metabolic chemistry
Pump antimicrobial drug out of the cell before it can
act
Mycobacterium tuberculosis produces MfpA protein
Binds DNA gyrase preventing the binding of
fluoroquinolone drugs
88
90. Resistance to Antimicrobial Drugs
• Multiple Resistance and Cross Resistance
▫ Pathogen can acquire resistance to more than one
drug
▫ Common when R-plasmids exchanged
▫ Develop in hospitals and nursing homes
Constant use of drugs eliminates sensitive cells
▫ Superbugs
▫ Cross resistance
90
91. Resistance to Antimicrobial Drugs
• Retarding Resistance
▫ Maintain high concentration of drug in patient for
sufficient time
Kills all sensitive cells and inhibits others so immune
system can destroy
▫ Use antimicrobial agents in combination
Synergism vs. antagonism
91
93. Resistance to Antimicrobial Drugs
• Retarding Resistance
▫ Use antimicrobials only when necessary
▫ Develop new variations of existing drugs
Second-generation drugs
Third-generation drugs
▫ Search for new antibiotics, semi-synthetics, and
synthetics
Bacteriocins
Design drugs complementary to the shape of
microbial proteins to inhibit them
93
94. Vaccination
• Vaccine – use the immune system to protect
against infectious disease
• Types of vaccines
▫ attenuated (weakened) microbe; virulence factors are
removed
▫ heat-killed / chemically killed microbe
▫ toxoids
• Passive versus Adaptive vaccination
▫ passive – immune system products from another
mothers milk (presence of IgA)
gamma-globulin (anti-bee venom, anti-hepatitis A, etc)
▫ active – stimulate individuals immune system to produce
memory cells
94
97. • Why Your Cellphone Has More Bacteria
Than a Toilet Seat
• By Susan E. Matthews, MyHealthNewsDaily
Staff Writer | LiveScience.com – 3 hrs ago
• http://news.yahoo.com/why-cellphone-more-
bacteria-toilet-seat-124147769.html
97
98. • Cellphones carry 10 times more bacteria than
most toilet seats, so it shouldn't be surprising
that a man in Uganda reportedly contracted
Ebola after stealing one.
• He stole the phone from a quarantined ward of a
hospital, near the site of a recent Ebola outbreak.
• While toilets tend to get cleaned frequently,
because people associate the bathroom with
germs, cellphones and other commonly handled
objects — like remote controls— are often left
out of the cleaning routine.
• Cellphones pick up germs all the time; some
people talk on their phone on toilets.
98
99. • However, the amount of germs on a phone isn't a
problem — it’s the sharing of phones between
people. Without sharing, each phone carries just
one set of germs, and won't get its owner sick.
• The problem with phones is that we're in
constant contact with them, and they spend a lot
of time in close proximity to our faces and
mouths.
• And, because it's an electronic device, most
people are hesitant about cleaning them.
99
100. • This is also this case with remote controls,
which, are also often used by people when
they're sick.
• Remotes are more frequently shared, too, so
they're usually even worse than phones for
spreading germs.
• Other common culprits that are hotspots of
unseen disease include office phones, shopping
carts and the first-floor buttons of elevators.
100