Compare the techniques used to prepare a lawn culture and streak culture Compare

Question

Compare the techniques used to prepare a lawn culture and streak culture Compare the purpose for each type of culture What is the significance of the clear zones around some of the antiseptic/disinfectant disks used in the Controlling the Growth of the Bacteria exercise? Based on what you learned in the Controlling the Growth of Bacteria what would you suggest as an effective way to clean a portable home humidifier which is typically a good environment for the growth of biofilms? Since the 1980 s infectious disease related deaths in the US are increasing significant Speculate on possible factors that may be contributing to this increase? in 1929. Alexander Fleming discovered the first antibiotic when he noticed that colonies of certain bacteria growing on culture plates appeared to die when the plates became contaminated with the fungus penicillium Fleming concluded that a substance secreted from the fungus was causing the bacteria to breakdown, and he called this substance penicillin. in its natural environment. what would be the adapts advantage of a fungus producing and secreting a bacterial inhibitor?

Explanation / Answer

Hey I can help you with the first 3 question answers that is question 2, 3 and 4.

2) The streak culture and Lawn culture:-

Streak culture is a routinely used culture technique used to isolate bacteria, in this method one loop full of culture is used a primary inoculum and is distributed thinly over the plate streaking it with the loop in a series of parallel lines in different segments of the plate. the loop is flamed and cooled in between different sets of streaks. after incubation, confluent growth will be seen at the rigin of the streak but becomes progressively thinner and well seperated colonies will be obtained towards the end of the streaks.

Lawn culture also called as carpet culture is a technique mainly used for antibiotic testing and bacteriophage typing. In this method a uniform layer of baterial growth is obtained by flooding the surface of the plate by liquid culture or suspension of bacterium, pipetting off the excess inoculum and incubating the plate. A cotten swab soaked in bacterial culture or suspension may also be used to inoculate the plate.

3) The clear zones that are seen around a antiseptic/ disinfectant disks show that the bacterial growing in that culture medium is sensitive to these disks and it is inhibiting their growth around the disks, that is these antiseptic/ disinfectant disks are able to inhibit the growht of the bacteria in that particular culture. The zone around an disk that has no growth is referred to as the zone of inhibition since this approximates the minimum antiseptic/ disinfectant concentration sufficient to prevent growth of the test isolate. This zone is then measured in mm and compared to a standard interpretation chart used to categorize the isolate as susceptible, intermediately susceptible or resistant.

4)Portable home humidifiers contain a water tank at the base which is the most comfortable site for bacteria and moulds to grow, to keep this area clean one shoud regularly change the water in the tank and also clean it using readily available chemiclas such as vinegar, bleaching powder or peroxides which are good antibacterial and anti fungal agents.

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