Microbial contamination of radiographic films in maxillofacial surgery clinics

Radiographic investigation in maxillofacial surgery is a vital procedure in minor as well as major surgical procedures in dentistry and in this Department, for example, both analog and digital radiography is used. Patient files are usually transferred from one clinic to another according to the patient appointments and most dentists and surgeons routinely handle these files before treating patients. Since radiographic films are not subjected to disinfection a variety of bacteria may be transferred from the oral cavity to these films and then to other patients via process of cross infection. Although most dental clinics are currently moving to digital technology even the use of this approach may lead to cross contamination, since the sensors and phosphor plates used in digital radiographs are also not generally autoclavable. The aim of the work described in this study was therefore to screen radiographic films used at the Maxillofacial Surgery clinics in the College of Dentistry, King Saud University for contamination with potentially pathogenic bacteria and fungi. A total of 447 radiographs films including periapical, occlusal and orthopantomograms (OPG) from patients treated at the clinics of Oral and Maxillofacial Surgery, College of Dentistry, King Saud University were collected in sterile plastic bags and screened for bacterial contamination. All films were swabbed using sterile swab sticks and bacteria were then identified using standard laboratory procedures. After identification of the contaminant bacteria, data were analyzed using SPSS software. The qualitative assessment of the tested samples showed that all tested radiographic films samples were contaminated with bacteria. Staphylococci (Staphylococcus aureus 33.8% and coagulase negative Staphylococcus epidermidis 18.1%) were the most frequently isolated bacteria, although species of Streptococcus (3.6%) and Bacillus (3.6%) were also isolated; only 23.5% of the tested films were contaminated with fungi, mainly Aspergillus niger. This study demonstrates that radiographic films can be a source of cross infection in dental clinics and since these films are not subjected to any disinfection there is a need for the application of strict hygiene measures during their handing in order to avoid cross infection of microorganisms from these films.