Further Pathogen Testing {Lab 12 - May 28, 2015}

     After the previous investigations of pathogens the class went further into testing what pathogens are resistant or susceptible to certain things.

Materials: 

• swabs
• antibiotics
• testing paper
• tweezer
• Bunsen burner
• piquet

Procedure: 

Cinnamon and Clove Mouthwash

     After preparing plates with MRSA, MRSA isolate, Staph aureus, and Staph aureus motile, we then, using the aseptic technique with the tweezer, placed a sample of penicillin (1), metecillin (2), vacomycin (3), linezolid (4), and augmentin (5) on each of the samples and placed the samples in the incubator. 

     We also prepared plates of the staph oral bacteria and tested different concentrations of salt solutions on one of the plates and on the other tried different mouth cleaning products of lemon, clove, a cinnamon and clove mouthwash, toothpaste, and chlorohexadine. 

     The last plate was our unknown which had already proven to be resistant to penicillin. So this time we treated the bacteria with penicillin on one side and an augmentin on the other.

Results/application: 

     The next day the Staph aureus proved to be resistant to the penicillin and methicillin and susceptible to the rest.

 The Staph aureus motile was sensitive to all of the antibiotics.

MRSA showed itself to be resistant to penicillin and methicillin, susceptible to vacomycin and linezolid and intermediate to augmentin.

     The MRSA isolate was penicillin, vacomycin and augmentin resistant and methicillin and linezolid susceptible. 

    

     Out of these linezolid had the greatest effect every time showing it to be the most effective antibiotic. Linezolid has recently been developed and bacteria like MRSA do not have any defenses against it.

     When checking the oral bacteria, the salt treatment seemed to have no effect on the bacteria. We suspect this is because we could not get the salt to fully dissolve in the water. However the other plate did have some results. The lemon was ineffective. The clove and cinnamon mouthwash had a moderate effect. However, it was the toothpaste and the chlorohexadine that had the greatest effect. 

     So toothpaste is a good investment in oral hygiene and if I want my mouthwash to do more then make my breath smell good I should look for some with chlorohexadine.

  

     The last plate with our unknown had results as well. Once again the penicillin had no effect. However the augment did. The augment contains clavulanic acid which destroys β-lactamase in the pathogen which prevent it from destroying the lactase ring in penicillin allowing the penicillin to do its job of breaking down the cell wall. This tells us that our bacteria has β-lactamase that works against the penicillin and it has a cell wall. 

The most curious part of our results that we did not understand was there was two rings around the augment the inside one containing no growth and the outer one containing some growth.