Detergents’ Effect on MRSA Survivorship

Matthew WisneskiGrade 9

Central Catholic High School

Stands for Methicillin resistant Staphylococcus aureus

Five major clones of MRSA are known, but two are most common-Hospital associated MRSA (HA-MRSA)-Community associated MRSA (CA-MRSA)

First identified in 1961

Common problem in today’s hospitals

Resistant to different antibiotics, including methicillin

MRSA

Blood poisoning Pneumonia Cellulitis Osteomyelitis (infection of the bones) Meningitis Increased risk of cardiac arrest Death

Complications of MRSA

Direct contact with another person who has the infection.

Sharing personal items that have previously touched infected skin

Touching items contaminated with MRSA

Dutch scientists concluded from a study that MRSA can be spread by patients constantly transferring between different hospitals.

How Is MRSA Spread?

Most strains have a mortality rate of 11%.

New strain, USA6000, has a stunning mortality rate of 50%.

Hospital-acquired MRSA infections killed 48,000 people and cost $8 billion to treat (2006)

In most hospitals, every patient is tested for presence of MRSA via a nasal culture.-If positive, patient is placed into isolation

MRSA Mortality Rates and Costs

A sign of MRSA is a bump on the skin that may be: painful; swollen; red; warm when touched; and full of pus.

Treating MRSA infections usually involves a healthcare professional draining the infection and prescribing an antibiotic.- Draining an infection individually is not recommended. It can make the infection worse or may spread the infection to other people.

Problem: The clothes of MRSA patients and hospital personnel must be cleaned and hopefully become free of MRSA.

Question: How effective are different detergents at eliminating MRSA?

MRSA Signs and Appearance

Clorox◦ Hazardous ingredients include sodium hypochlorite

and sodium hydroxide.◦ Corrosive and can cause irritation to eyes and skin.

Tide ◦ Ingredients include sodium carbonate, alkyl sulfate,

and benzene sulfonic acid.◦ Can be an eye and a skin irritant.

Cheer◦ Ingredients are ethyl alcohol, sodium borate, and

ethanolamine.◦ Harmful if swallowed and is an eye irritant.

Ingredients of Detergents

Melaleuca◦ No harmful effects of this detergent are known.◦ Only ingredient is thymol (component of thyme

oil).◦ Natural detergent

All◦ Ingredients include sodium carbonate, sodium

aluminosilicate, and alcohol ethoxylate. ◦ An eye irritant and may be harmful if swallowed.◦ No skin irritation with brief contact.

Ingredients of Detergents (continued)

To test the lethality effects of detergent concentrations on MRSA.

Purpose

Null Hypothesis: The concentrations of detergents will not have a significant effect on MRSA survival.

Alternate Hypothesis: The concentrations of detergents will significantly reduce MRSA survivorship, and Clorox will reduce survivorship the most.

Hypotheses

Tide, Cheer, All, Clorox, Melaleuca (Detergents) Test tubes 26 agar plates Sterile saline solution Liquid MRSA suspension Sterile heater Centrifuge Incubator Filter paper Ruler Scissors and tongs Lab coat and gloves Biohazard safety bin Sterile swabs

Materials

1. Tongs and scissors were sterilized in a portable sterilizing unit.

2. Agar plates were labeled for each detergent and trial. All concentrations per detergent were labeled in a quadrant of one plate.

3. 1 cm square sterile filter papers were created.4. Squares were placed into a sterile container.5. Detergent solutions were prepared in saline (25%, 50%,

75%, and 100%).6. Solutions were centrifuged for homogenization.7. Using sterilized tongs, a detergent disc was placed into a

solution.

Procedure

8. Discs were soaked in the solutions for 30 minutes.

9. Sterile swabs were used to create confluent lawns of MRSA on each plate.

10. Each disc was placed into the corresponding quadrant of the agar plate.

11. All biohazard waste was disposed of in a biohazard safety bin.

12. Plates were incubated for 48 hours.13. Results were measured in terms of impact zones

of the detergent discs (millimeters).

Procedure (continued)

Variables 0% 25% 50% 75% 100%

Detergent 0 mL 2.5 mL 5 mL 7.5 mL 10 mL

Saline 10 mL 7.5 mL 5 mL 2.5 mL 0 mL

TOTAL 10 mL 10 mL 10 mL 10 mL 10 mL

Table of Concentrations

Detergents’ Effect on MRSA Survivorship

0% 25% 50% 75% 100%0

10

20

30

40

50

60

SalineAllCheerMelaleucaTideClorox

Concentrations

Avera

ge I

mp

act

Zon

e (

mm

)

P-value: 3.61E-22

25% and 50% Concentration Effects on MRSA Survivorship

0% 25% 50%0

10

20

30

40

50

60

Saline

All

Cheer

Melaleuca

Tide

Clorox

Concentrations

Avera

ge I

mp

act

Zon

e (

mm

)

P-value: 9.95E-05

P-value: 1.55E-06

75% and 100% Concentration Effects on MRSA Survivorship

0% 75% 100%0

10

20

30

40

50

60

Saline

All

Cheer

Melaleuca

Tide

Clorox

Concentrations

Avera

ge I

mp

act

Zon

e (

mm

)

P-value: 1.35E-07

P-value: 7.11E-08

Variable Concentration T-value Interpretation

25% All 5.76 Significant

25% Cheer 4.75 Significant

25% Melaleuca 4.39 Significant

25% Tide 2.42 Not Significant

25% Concentration Dunnett’s TestT-critical: 3.48

50% Concentration Dunnett’s TestVariable Concentration T-Value Interpretation

50% All 7.41 Significant

50% Cheer 7.01 Significant

50% Melaleuca 5.77 Significant

50% Tide 3.47 Not Significant

T-critical: 3.48

Variable Concentration T-value Intrepretation

75% All 9.21 Significant

75% Cheer 8.54 Significant

75% Melaleuca 7.54 Significant

75% Tide 5.81 Significant

75% Concentration Dunnett’s Test

T-critical: 3.48

Variable Concentration T-value Intrepretation

100% All 8.71 Significant

100% Cheer 8.55 Significant

100% Melaleuca 6.94 Significant

100% Tide 6.43 Significant

100% Concentration Dunnett’s Test

T-critical: 3.48

With the low p-value, it can be determined that the concentrations did have a significant effect on MRSA survivorship.

Null hypothesis is rejected.

Through the Dunnett’s Test, it can be concluded that Clorox had an overall significant variation from the other variables used, thus supporting the hypothesis of Clorox reducing MRSA survivorship the most.

Conclusions

Limitations◦ Detergent discs not always the same size.◦ Discs may have inconsistent amounts of

detergent.

Extensions◦ Test lower concentrations of detergent so that it

gives an accurate representation of actual percentage of detergents used in laundry.

◦ Test effects of detergents on MRSA that may be on hospital gowns, lab coats, etc.

Limitations and Extensions

Huff, E. “Deadly MRSA superbug has 50 percent mortality rate in hospital patients.” NaturalNews.com. 30 November 2009. Web. 26 December 2011.

 Hitt, Emma. "MRSA Found in 4% of Healthcare Workers; Most Are Healthcare-Related Strains." http://www.medscape.com. 6 Apr. 2010. Web. 24 Oct. 2011.

Lin, Michael Y., and Mary K. Hayden. "Methicillin-resistant Staphylococcus aureus and Vancomycin-resistant enterococcus: Recognition and Prevention in Intensive Care Units." Critical Care Medicine 38.8 (2010): S335-344. Print.

Jain, Rajiv, and Stephen M. Kralovic, et al. "Veterans Affairs Initiative to Prevent Methicillin-Resistant Staphylococcus aureus Infections." The New England Journal of Medicine (2011): 1419-430. Print.

Bibliography

Johnston, B. Lynn, and Elizabeth Bryce. "Hospital Infection Control Strategies for Vancomycin-resistant Enterococcus, Methicillin-resistant Staphylococcus aureus and Clostridium difficile." Canadian Medical Association Journal (2009): 627-31. Print.

Material Safety Data Sheets (MSDS) for all detergents.

“MRSA Complications.” MED Info. 2010. Web. 26 December 2011. www.mrsaskininfections.org.

"MRSA 'spread by patients moving between Hospitals'" BBC.com. 12 Jan. 2010. Web. 22 Jan. 2012.

"National MRSA Education Initiative: Preventing MRSA Skin Infections."  CDC.gov. 9 Aug 2010 Web. 22 Jan. 2012.

Bibliography (continued)

Resulting Impact Zones (mm)