Testing MRSA and other Pathogens {Labs 10 and 11 - May 26 and 27, 2015}

Caution:

      For these tests we were working with pathogens meaning they can be harmful. So precautions are needed and anytime we are handling them gloves must be worn and wash hands immediately afterward.  The purpose of these tests are to see what kind of cleaning products might prevent these pathogens from growing.

Materials:

·       Gloves

 The products that we
would be putting to the test.

·       Swabs

·       dish washing foam

·       Scott cleaner (choloroxlenol)

·       Clorox bleach

·       Lysol (phenol)

·       lens cleaner (Biguaninde)

·       tincture

·       acid alcohol

·       70% isopropyl alcohol

·       H₂O₂

·       Mouthwash

·       Tweezers

·       Bunsen burner

Procedure:

      The first thing was to retrieve the pathogens from storage. Note pathogens’ plates are sealed for safety when is storage. Our group was working with MRSA and the others had VRSA, a staph bacteria that grows in the oral cavity, and a MRSA isolate. Once I had my sample I inoculate the agar plates using a swab to spread the MRSA over both plates entirely.

     Then small circular test paper must be placed in designated areas on the plates, 5 per plate. To do this tweezers are used. Before placing every testing paper the tweezers are sterilized by dipping it in 70% ethanol and then heating it with the Bunsen burner. Once the tweezer is sterilized a testing paper is picked up from its petri dish and placed in one of the designated areas. This is repeated for all 10 sections. Next a pipet is used to place 5µm of a cleaning product is placed on a testing paper. And the plates are incubated at 37⁰C for 24 hours.

Results and applications:

     The MRSA proved to be susceptible to the dish washing foam(1), the Scott’s cleaner(2), the Clorox bleach(3), the Lysol(4), and the tincture(6). 

MRSA Plates

The oral bacteria, S. aureus was susceptible to the dish washing foam (1), the Scotts cleaner (2), the bleach (3), the Lysol (4), the tincture (6), and the H₂O₂ (9). 

Staph Aureus

The VRSA was susceptible to the dish washing foam (1), the Scott cleaner (2), the bleach (3), the Lysol (4), the tincture (6), and the H₂O₂ (9). 

MRSA Isolate (middle and left)

Finally the MRSA isolate was susceptible to the dish washing foam, the bleach, the Lysol, the tincture, and the H₂O₂.

     After looking at the results it was odd to see that the MRSA was resistant to the H₂O₂ and we wonder if the 5µm were added correctly.

     The dish washing foam proved to be the most effective of all the disinfectants every time as it had the largest radius of a clean zone around it (about 30mm on the MRSA). It is good to know that the dishes at home are safe from these harmful pathogens. And a good scrub down with bleach can be effective as well. The mouthwash, which was specifically used for the oral bacteria, had no effect so that one won’t clean your mouth but it still eliminates the bad breath.

     Now we know what household cleaners can eliminate certain pathogens. So if we know what pathogen is affecting a certain family member, we know which cleaner to use so as to eliminate the pathogen.