THE TYPE AND AMOUNT OF BACTERIA FOUND IN AN
AMBULANCE AND THE
DISINFECTANTS USED TO TRY TO KILL THEM


Andrew 3. Woodard
School of Science and Natural Resources
Lake Superior State University
Sault Ste. Marie, MI 49783







Abstract. Keeping a clean and relatively bacteria free environment in the back of an
ambulance can help reduce the chance of patients acquiring an infection. Therefore, in this
experiment one ofthe ambulances, from Public Safety Ambulance (PSA) in Sault Ste.
Marie, was tested to determine how well it was being cleaned. Wavicide, which is the
disinfectant used by PSA, was also tested against three other common disinfectants.
These disinfectants included 1O% bleach, 70% ethanol, and Amphyl. Three trials were
performed. Samples were collected from six different sites in the back ofthe ambulance
with the use of swabs, which were used to inoculate nutrient agar plates. After the
inoculated agar plates had been incubated, the bacteria were counted and Gram stains
were performed. Broth cultures were inoculated for each ofthe bacteria colonies tested.
Disinfectant tests were then done in which representative broth cultures were tested
against all four disinfectants simultaneously. The analyzed data revealed that agar plates
from the sites that were in pnmary contact with a technician had more bacteria colonies
than the sites that were in pnmary contact with a patient. The back ofthe ambulance
contained more Gram negative bacteria than Gram positive bacteria. Amphyl and 70%
ethanol seemed to be more effective than Wavicide and l0% bleach after 2.5 minutes;
however, not enough samples were tested to determine if these results were statistically
accurate. At 5 and 10 minutes, the four disinfectants were equally effective.



Selected References

	Case, C.L., & Johnson, T.R. (1995). Laboratory Experiments in Microbiology
(Fourth Edition). Redwood City, California: The Benjamin/Cummings Publishing
Company, Inc.

	West, K. (1994, March-April). Vehicle Maintenance, An Infection Control
perspective. Rescue-EMS Magazine, 28-31.