Control of microbial growth
physical agents
chemical agents
mechanical means
Types of physical agents in control of microbial growth
heat (dry and moist)
radiation
Types of dry heat
dry oven
incineration
Types of moist heat
Non-pressurized
Pressurized
Examples of non-pressurized moist heat
hot water
boiling water
pasteurization
What are the 2 methods of pasteurization?
Batch method (LTHT)
Flash method (HTLT)
Flash method pasteurization
- 75 degrees Celsius for 15 seconds
Batch method pasteurization
65 degrees Celsius for 30 mins
Pasteurization MUST
maintain taste
maintain nutritional value
Example of pressurized moist heat
Autoclave
Units of autoclave
- Psi 15
- Temp of 121 degrees Celsius
- Time 10-40 mins
Types of radiation
ionizing
non-ionizing
Examples of ionizing radiation
X-ray
Cathode ray
Gamma-ray
Example of Non-ionizing radiation
UV Ray (thymine dimers)
What part of the body is microbe free?
All bodily fluids, tissues, and organs
Example of mechanical means to control microbial growth
filtration
HEPA filter stands for
High Efficiency Particulate Air
Nosocomial infections
Healthcare-associated infections, infection(s) acquired during the process of receiving health care that was not present during the time of admission.
What do you understand by drug susceptibility testing?
Testing is essential in those groups of bacteria commonly showing resistance
How are antibiotics produced?
Antibiotics are produced industrially by a process of fermentation
When do we use filtration to control microbes?
Filtration is used to sterilize heat-sensitive materials, such as culture media, enzymes, vaccines, and antibiotic solutions.
Which portal of entry is most used?
Typically a cutaneous or membranous route
What is oligodynamic action?
Small amount of heavy metal dust is used to destroy a wide range of microbes
Drugs are…
ideal, NOT perfect
what are Beta-lactam composed of?
Beta (B) lactam ring
Thiazolidine ring
Variable “R”
What is chemotherapy?
The use of chemical substances or drugs to treat or prevent disease
What is pasteurization?
Heat treatments of perishable fluids such as milk, fruit juices, or wine to destroy heat-sensitive vegetative cells, followed by rapid chilling to inhibit growth of survivors or germination of spores. It prevents infections and spoilage.
What are macrolides?
Any of a class of antibiotics containing a lactone ring, of which the first and best known is erythromycin.
What are aminoglycosides?
Inhibits protein synthesis
What are polymyxins?
A mixture of antibiotic polypeptides from Bacillus polymyxa that are particularly effective against gram-negative bacteria
What is superinfection?
An infection occurring during antimicrobic therapy that is caused by an overgrowth of drug-resistant microorganisms
What is therapeutic index?
The ratio of the toxic dose to the effective therapeutic dose that is used to assess the safety and reliability of the drug
Broad spectrum drugs
a class of antibiotics that act against an extensive range of disease-causing bacteria by targeting both gram-positive and gram-negative bacterial groups
Narrow spectrum drugs
target a few types of bacteria
Properties of drugs
Effectiveness
Safety
Selectivity
Microbicide
Kills microbes
Microbistatic
Inhibits microbe growth
Food irradiation
A food safety process that uses radiation to kill germs that can cause food poisoning (foodborne illness).
Chlorhexidine
A broad-spectrum antimicrobial biguanide used as a topical antiseptic and in dental practice for the treatment of inflammatory dental conditions caused by microorganisms
Stages of clinical infection
The incubation period
The prodromal stage
The period of invasion
The convalescent period
The incubation period
The period of time from the initial contact with an infectious agent to the appearance of the first symptoms
The prodromal stage
The earliest notable symptoms of infection appear as a vague feeling of discomfort, lasts about 1-2 days
Period of invasion
The period during a clinical infection when the infectious agent multiplies at high levels, exhibits its greatest toxicity, and becomes well established in the target tissue
The convalescent period
Patient begins responding to the infection, the symptoms decline and the patient’s strength and health gradually return
Microbiota
The native types of bacteria, fungi, and viruses that normally reside on the body
What is infection?
The entry, establishment, and multiplication of pathogenic organisms within a host
Thermal death time (TDT)
The least time required to kill all cells of a culture at a specified temperature
Sterilization
Any process that COMPLETELY removes or destroys all viable microorganisms
Initial colonization of the newborn
Rupturing of the amniotic sac exposes the baby to microbes carried by the mother.
Paba
is synthesized and utilized as a substrate for the synthesis of folic acid in many bacterial species, yeasts and plants
Salvarsan
a drug that was introduced at the beginning of the 1910s as the first effective treatment for syphilis, relapsing fever, and African trypanosomiasis
Halogens
A group of related chemicals with antimicrobial applications. most often used are chlorine and iodine
Tincture of iodine
Used as an antiseptic that can be applied on cuts, wounds, scratches, etc. It is also used to disinfect water from viruses and bacteria. Wounds can also be cleaned and disinfected by using the tincture of Iodine.
What are the 8 properties of drugs?
inhibit/destroy a wide range of microbes (Broad-spectrum)
prevent the development of antibiotic resistance
prevent the development of superinfection
soluble
not easily excreted
high concentration
available
affordable