Bacterias are present in the environment and really closely related to human wellness and disease. Environment bacteriums are those that can turn at ambient temperatures or 25 & A ; deg ; C.
Bacteria are prevailing in dirt, H2O, normal vegetations and many other environments ; bacteriums in the environment can present a unsafe hazard to the human wellness, particularly n infirmaries, industries and agribusiness. The initial phase of infection is contact or exposure to micro-organisms via inspiration, consumption or cuticular contact, therefore it is really of import to cognize the being of microorganisms in a known environment such as infirmary or industry for the bar of infection to perchance the immuno-compromised or ill patients in infirmaries and to forestall taint of nutrient or medical specialties in the industries.During this survey environmental sampling of a biohazard category 2 research lab was carried out from the air and surface. The hypothesis was that there should be minimum bacterial being on the surface of the benches since they are disinfected after each lab. Most counts should be expected from the air samples because pupils and staff leave and enter the lab ; some will cough or sneeze and bacteriums from normal vegetations can besides act upon bacterial counts.The microbic air taint can be measured utilizing active air sampling stations, which collect air of a known volume on to a alimentary agar home base or by inactive air trying via settle home bases, where alimentary agar home bases are left in any portion of the environment for a certain sum of clip and so incubated.
The active air sampling stations are expensive, hard to sterilize and the sampling station sometimes gives different consequences. Whereas the settee home bases are inexpensive, unfertile dependable and many samples can be taken in different topographic points, at the same clip.The microbic air taint measurings provide qualitative information about the types of bacteriums present in air, hence appropriate steps to cut down airborne disease can be taken such as have oning protective masks. The measurings of surface taint is besides really of import because infection can besides because by cuticular contact to surfaces.The measuring of surface taint can be carried out utilizing contact home bases, swab samples from different surfaces and templet samples from different surfaces.
The contact plates help to supply quantitative and more sensitive consequences in comparing to the swab samples.Once the bacterial samples have been taken from the air or surface of the environment, it is of import to insulate and place the bacteriums so that the cause of the taint or disease may be identified. The isolation of bacterium has to be done utilizing sterile techniques. The most common method of bacterial isolation is to streak the unknown sample on to a alimentary agar home base and incubate overnight for farther designation.The designation of bacteriums can be done utilizing assorted techniques ; some of these techniques are discussed below.
The Gram discoloration technique was first developed in 1884 by the Danish scientist Hans Christian Gram and is an first-class method for distinguishing among bacteriums based on differences in their cell was construction ; this information can so be used to aim bacterial pathogens with appropriate antibiotics or even germicides. The Gram positive such as staphylococci aureus have more peptidoglycan in their cell wall and hence the crystal violet discoloration is retained by these bacteriums.
The Gram negative bacteriums such as E. coli have thinner cell walls ; incorporating an outer bed of lipopolysaccharides which is disrupted by intoxicant wash. This break allows the crystal violet dye to get away and hence these cells appear pink under the microscope, whereas the gm positive bacteriums appear violet under the microscope.
Differential and selective media
The term media refers to agar home bases used for the growing of bacteriums in a research lab environment. Some types of agar are capable of turning anything, whereas some are differential or selective media. Selective media excludes some types of bacterial growing, whereas differential media allows for a color alteration to take topographic point which reveals bacteriums that may hold specific metabolic capablenesss.
MacConkey ( Mac ) agar is used for the selective isolation and designation of bacteriums from fecal matters, piss, effluent and nutrients. It can besides be used as a selective media for the isolation of enteral Gram negative bacteriums such as E.coli. The Mac agar besides contains a differential pH index which changes coloring material of the agar in the presence of bacteriums that can ferment the sugar milk sugar.
Mannitol Salt ( MS ) agar is high in Na chloride content and therefore is selective for halophiles ( salt-loving ) bacterium. MS besides has a pH index that changes colour when there are bacteriums present that can ferment the sugar Osmitrol. The bacteria staphylococci aureus grows truly good on this agar and produces a coloring material alteration to yellow as a Osmitrol fermenter.The Bair Parker ( BP ) agar is a reasonably selective and differential agar for the isolation and numbering of staphylococci aureus in nutrient and environmental samples. Staphylococcus aureus grows good on BP agar with dark Grey to shiny black medium sized settlements, surrounded by aura due to the dislocation of egg yolk with lecithinase produced by S.aureus.