An evaluation of microbiologic contamination on phosphor plates in a dental school.
OBJECTIVE
The objective of this study was to determine if phosphor plates used in predoctoral clinics are microbiologically contaminated and to identify the source of contamination.


METHODS
Forty-five of 300 phosphor plates (15%) were randomly selected for examination. The plates were pressed into individual blood agar plates, were incubated using standard techniques at 37 degrees C, and were monitored for 72 hours. The number, size, distribution, and variety of resulting colonies were noted. A representative of each type of colony was selected to be Gram stained using the standard technique.


RESULTS
Of the plates, 42.2% were uncontaminated, 57.8% yielded bacterial colonies, and 15.6% of those colonies demonstrated hemolytic growth. The hemolytic growth included combined alpha and beta hemolysis and beta only hemolysis. Six colonies were gram-positive rods and 7 were gram-positive cocci.


CONCLUSIONS
Meticulous infection-control techniques are inevitable and continuous reinforcement and training for staff and students are mandatory. Periodic gas sterilization of phosphor plates may be necessary.
Kalathingal
Sajitha Menon
SM
Oral Health and Diagnostic Sciences, School of Dentistry, Medical College of Georgia, 1120 15th Street, Augusta, GA 30912-1241, USA. skalathingal@mail.mcg.edu
Moore
Stephanie
S
Kwon
Soon
S
Schuster
George S
GS
Shrout
Michael K
MK
Plummer
Kevin
K
D015169:Colony Count, Microbial; D003740:Dental Clinics; D004866:Equipment Contamination; D006095:Gram-Positive Cocci / Q000302:isolation & purification; D016987:Gram-Positive Rods / Q000302:isolation & purification; D006801:Humans; D019552:Infection Control, Dental / Q000379:methods; D019252:Radiography, Dental, Digital / Q000295:instrumentation*; D013242:Sterilization / Q000379:methods; D013291:Streptococcus / Q000302:isolation & purification; D014963:X-Ray Intensifying Screens / Q000382:microbiology*