Question

49.

A.  Differentiate between the terms "aseptic technique" and "sterile". Offer examples of situations in which each is appropriate.

B.  Discuss several different physical and chemical methods of controlling microbial growth in various environments.

C. Thoroughly explain plausible consequences of failing to control microbial growth in various environments.

Answer 1

Aseptic and sterile go hand in hand. Aseptic means something has bee made contamination free and will not produce or transfer a harmful living micro organism like bacteria or virus. Techniques done asepticaly are called aseptic technique.

Where as steril is free of all germs without discrimanting helpful or harmful microorganisms

A technique to reach aseptic is more specific and thus complex. It requires the knowledge of which bacteria is harmful and which is not. it requires the removal harmful while keeping alive the beneficial ones. Where as sterile is brutal, more radical has no need to preserve any living organisms.

Sterilized conditions are used in medical tools and they are difficult to achieve on a ;larger scale where as aseptic condition use set of hygenic rools whose goal is to limit infection in a zone that is impossible to sterilze entirely like a waiting room.

2. Microorganisms are controlled by means of physical agents and chemical agents. Physical agents include such methods of control as high or low temperature, desiccation, osmotic pressure, radiation, and filtration. Control by chemical agents refers to the use of disinfectants, antiseptics, antibiotics, and chemotherapeutic antimicrobial chemicals.

Temperature

Microorganisms have a minimum, an optimum, and a maximum temperature for growth. Temperatures below the minimum usually have a static action on microorganisms. They inhibit microbial growth by slowing down metabolism but do not necessarily kill the organism. Temperatures above the maximum usually have a cidal action, since they denature microbial enzymes and other proteins.

Different forms of heat used are dry heat ( hot air , incineration and pasteurization), moist heat, boiling water, steam under pressure (autoclaving), low temperatures.

Dessication

Desiccation, or drying, generally has a static effect on microorganisms. Lack of water inhibits the action of microbial enzymes.

Osmotic pressure

osmosis cause either water to move either inside the cell when cell encounter an hypotonic enivironment leading to swelling up and lysis or water to move out of cell when the cell encounters a hypertonic solution leading to cell shrinkage and death.

Radiation

various radiations like ultra violet rays, ionizing radiations like x rays and gamma rays can disrupt the DNA molecules and proteins.

Filtration

The filters contain pores small enough to prevent the passage of microbes but large enough to allow the organism-free fluid to pass through. used to sterilize substance damaged by heat, radiation and chemical agents.

Chemical Methods

In addition to physical methods of microbial control, chemicals are also used to control microbial growth. A wide variety of chemicals can be used as disinfectants or antiseptics.

Phenols

several phenolic compounds are used to control micor organism.

Heavy Metals

Heavy metals kill microbes by binding to proteins, thus inhibiting enzymatic activity.

Halogens

iodine, chlorine, and fluorine. Iodine works by oxidizing cellular components, including sulfur-containing amino acids, nucleotides, and fatty acids, and destabilizing the macromolecules that contain these molecules.

Alcohols

They work by rapidly denaturing proteins, which inhibits cell metabolism, and by disrupting membranes, which leads to cell lysis.

Surfectants

Surface-active agents, or surfactants, are a group of chemical compounds that lower the surface tension of water. Surfactants are the major ingredients in soaps and detergents.

Bisbiguanides

Cholerhexidine is and example. It has broad-spectrum activity against yeasts, gram-positive bacteria, and gram-negative bacteria.  Chlorhexidine disrupts cell membranes and is bacteriostatic at lower concentrations or bactericidal at higher concentrations, in which it actually causes the cells.

Alkylating agents

Formaldehyde (CH2OH) is commonly used in solution at a concentration of 37% (known as formalin) or as a gaseous disinfectant and biocide. It is a strong, broad-spectrum disinfectant and biocide that has the ability to kill bacteria, viruses, fungi, and endospores, leading to sterilization.

Glutaraldehyde is structurally similar to formaldehyde but has two reactive aldehyde groups, allowing it to act more quickly than formaldehyde. It is commonly used as a 2% solution for sterilization and is marketed under the brand name Cidex.

Ethylene oxide is a type of alkylating agent that is used for gaseous sterilization. It is highly penetrating and can sterilize items within plastic bags such as catheters, disposable items in laboratories and clinical settings (like packaged Petri dishes), and other pieces of equipment.

Peroxygens

Peroxygens are strong oxidizing agents that can be used as disinfectants or antiseptics. The most widely used peroxygen is hydrogen peroxide (H2O2). Hydrogen peroxide works by producing free radicals that damage cellular macromolecules. Hydrogen peroxide has broad-spectrum activity, working against gram-positive and gram-negative bacteria (with slightly greater efficacy against gram-positive bacteria), fungi, viruses, and endospores.

3. Controlling microbial growth is important in the medical field, pharmaceutical and biotechnology industries, academic research, and food industry.

People have invented different techniques to control microbial spread. Controlling microbial growth is important in the medical field, pharmaceutical and biotechnology industries, academic research, and food industry.

Endospores are considered the most resistant structure of microbes. They are resistant to most agents that would normally kill the vegetative cells they formed from.

Mycobacterial infections are difficult to treat. Protozoa cysts are quite hard to eliminate too. Gram negative species have high levels of natural antibiotic resistance. Staphylococcus aureus is one of the major resistant human pathogens.

Fungal cells as well as spores are more susceptible to treatments. Vegetative bacterial and yeasts cells are some of the easiest to eliminate with different treatment methods. Viruses, especially enveloped ones, are relatively easy to treat successfully with chemicals due to the presence of lipids.

In medical field controlling microbes essential to prevent spreading of diseases. In operation theator surgeries are made which open up intact skin so if microbes are not controlled there lead to postoperative infection which is fatal.

In waiting rooms in hospital microbes are to be controlled as to prevent spreading of microbes from an infectious person to others.

All the equpment used in medical feild that comes in contact with skin shoul be free of microbes if not will lead to spread of infection.

Food stuffs stored should be free form microbes if not it will lead to food poisoning which is fatal.

Pharmaceutical needs a micorbe contol as they prodce medicines which should be microbe free if not will due spread of infection.