compare these microorganisms between a professionally cleaned car, and one that has not been cleaned in two months.
Dirty Car vs. Clean CarPerson #1 Person #2
August 2, 2012
The premise of this group project was to test the amount and type of bacteria found on the outside and inside of a car, and to compare these microorganisms between a professionally cleaned car, and one that has not been cleaned in two months. The surfaces that were tested stayed consistent between the vehicles, and the one who owned and operated each was the same as well. It was decided that the most commonly touched areas, and what was deemed as the most unclean parts were chosen as the areas that would be examined; these areas within the car were the steering wheel and air vents, while the ones chosen outside were the gas cap lid and drivers side door handle. This groups hypothesis was that a professionally cleaned car would culture far less bacteria in all areas than a non-cleaned car.
The process utilized inoculating two nutrient agar plates, each sectioned into four quadrants: Quadrant one for the steering, quadrant two for the door handle, quadrant three was the air vent, and quadrant four was the gas handle. The two plates were used as a separate growth plate for each car. For this experiment, the group used distilled water as a method of moisturizing sterile swabs prior to swiping a surface for bacteria. The swabs were done one at a time, with each being used to inoculate the agar plates immediately after acquiring the bacterial samples from the surface so as to reduce the collection of bacteria in the air.
Results The bacteria cultures from the dirty car and the clean car were surprisingly different. The dirty car had a total of eleven colonies from the steering wheel, air vent, door handle and gas handle combined. The steering wheel of the dirty car had only one large, beige, circular, convex colony 6 millimeters in size. The air vent of the dirty car had no growths after incubation. The door handle had six colonies ranging from cream to white in color, a variety of appearances and elevations and sizes ranging from 1 millimeter to 3 millimeters. The gas handle of the dirty car had four colonies ranging from cream to brown in color, a variety of colony appearances and elevations and the sizes ranged from 1 millimeter to 5 millimeters. The majority of identifiable bacteria from the dirty car appeared to be gram positive cocci.
The clean car had a total of fifty two colonies from the steering wheel, air vent, door handle and gas handle combined. The steering wheel had fourteen colonies ranging from cream to yellow to light brown in color, all circular in appearance, convex to umbonate in elevation and 1 to 6 millimeters in size. Unlike the dirty car, the clean cars air vent had seven colonies from cream to yellow in color, various in appearances, margins and elevations and 1 to 2.6 millimeters in size. The door handle of the clean car had seven colonies ranging from cream to orange in color, a variety of appearances, margins, and elevations and sizes ranging from 1 millimeter to 5 millimeters. The gas handle of the clean car had twenty-three colonies ranging from cream to yellow in color, a variety of colony appearances, margins and elevations and the sizes ranged from 1 millimeter to 5 millimeters. After gram staining procedures and careful evaluation under the microscope it was determined that the clean car had both gram positive cocci and gram positive bacillus bacteria. There was also a development of mold on the clean car agar plate. The mold or fungi was most noticeable under the microscope.
In conclusion, the clean car had forty one more bacterial colonies grown when incubated compared to the dirty car. The largest colony from each of the cars measured six millimeters in size and both of these large colonies originated from the steering wheels. The most abundant growth of colonies from a single location came from the gas handle of the clean car. The clean cars gas handle had a total of twenty three colonies while the gas handle of the dirty car only had four. Accounting for the size and quantities of all colonies we can conclude that the clean car was actually more dirty than the dirty car.
After examining the results, it was evident that a professionally cleaned car did not drastically improve the amount of bacteria cultured. In fact, the air vent of the dirty car showed no bacterial growth of any kind, which could be attributed to the fact that it has been stored outdoors while the clean car is parked inside a garage; the exposure of heat from the sun could have limited the growth of any microbial organisms. Also, it is unknown what types of cleaning products were used, thus making the anti-microbial control undetermined as well. Another factor to consider as uncontrollable is the usage of distilled water instead of sterile water. It is important to note that both vehicles saw large amounts of bacteria, and in the case of the dirty cash, fungal growth, in the samples taken from the gas caps. This can be attributed to the fact that his area of the car does not regularly get cleaned even when taken to a car wash.
Research by Reuters (2012) and Geekosystem (2011) shows that regardless of a clean car or a dirty car, the gas handle was the number one spot for bacterial colonies. In a study by Kimberly-Clark (2012), measurements were taken of repeated swabs of commonly touched objects and surfaces to determine the levels of adenosine triphosphate, which indicates the presence of contamination by an animal, vegetable, bacteria, yeast and mold cells (Geekosystem 2011). Gas pump handles were among the dirtiest surfaces Americans touch. This new testing is compelling because it underscores the importance of hand and surface hygiene (Livescience 2011).
Most cold and flu viruses are spread because people touch surfaces in their immediate area and then touch their faces, other objects and other people (Wikepedia 2012). Washing and drying your hands frequently throughout the day, can help prevent your risk of getting sick or spreading illness (Wikipedia 2012).
In Hong Kong, environmental staphylococcal contamination was investigated by culturing 400 automated teller machines (ATMs). Isolates were characterized for antibiotic and antiseptic susceptibility, carriage of antiseptic resistance genes (QAC genes), and spa types. MRSA, which was similar to local clinical isolates, was present on two (05%) of the 62 (155%) ATMs that yielded Staphylococcus aureus (Zhang et. al 2012).
Furthermore, handrails in 85 public urban buses were screened for the occurrence of MRSA in Portugal between May 2009 and February 2010 where 22 (26%) of the buses showed contamination (Simes et. al 2011). With bacterial contamination stemming from common surfaces one must be cognizant of what they are touching. Public transportation and personal cars are home to bacteria and even some fungal growth. Mold or fungal growth was also found in the clean cars, gas handle colonies.
Whether a car is professionally detailed or not has nothing to do with the amount of microbes present on the surfaces. Research around various parts of the world provides insight to harmful germs found in cars both seen and unseen to the naked eye. From a privately owned vehicle to public transportation, germs are spread at a rapid rate with passengers unsuspecting of these organisms since they are not visible.
In October 2011, Kimberly Clark released results of a study conducted in six United States cities regarding breeding grounds for the worst bacteria and viruses. The study found that gas pump handles were the filthiest surface that Americans encounter on the way to work (Reuters 2011). This study by Kimberly Clark is conclusive with the results of the Dirty Car vs. Clean Car study in that the gas handles yielded higher colonies of bacteria and mold than the other surfaces tested.
Research at the Queen Mary University in London, England (2011) revealed the steering wheel of a vehicle harbors nine times more germs than a public toilet seat; 80 types of bacteria lurk on each square inch of a toilet and 700 types inhabit the interior of the car (Dailymail 2011). Among the types of bacteria found were Bacillus cereus which can cause food poisoning and Arthrobacter, which is found in soil and on human skin. Dr. Ron Cutler, Director of Biomedical Science at Queen Mary stated, While most of the bacteria are unlikely to cause health problems, some cars were found to play host to a number of potentially harmful bacterial species (Dailymail 2011).
NYTimes (2011) reported that Darleen Franklin, a supervisor at San Francisco Universitys biology lab, took specimens of a BART (Bay Area Regional Transit) train. Ms. Franklins findings were fecal and skin born bacteria resistant to antibiotics. Further testing indicated the presence of MRSA in the trains cushioned seats (NYTtimes 2011). High concentrations of bacteria and mold were found on the public transit system. These findings are also conclusive to the Dirty Car vs. Clean Car study in that both bacteria and mold were present on frequently touched surfaces.
Dailymail.co.uk. 2011. How clean is your car? Retrieved from http://www.dailymail.co.uk/news/article-1379830/How-clean-car-Steering-wheels-times-germs-public-toilet-seat.html on August 1, 2012.
Geekosystem.com. 2012. Gas pumps are Gross. Retrieved from http://www.geekosystem.com/gas-pumps-are-gross/ on July 30, 2012.
Nytimes.com. 2011. On BART trains, the seats are taken by bacteria. Retrieved from http://www.nytimes.com/2011/03/06/us/06bcseats.html?pagewanted=all on August 1, 2012.