Microbiological contamination in digital radiography: evaluation at the radiology clinic of an educational institution / Contaminação microbiológica em radiografias digitais: avaliação da clínica de radiologia de uma instituição de ensino

The aim of this study was to evaluate the contamination rate of intraand extraoral digital Xray equipment in a dental radiology clinic at a public educational institution. Samples were collected on three different days, at two times in the day: in the morning, before attending patients, and at the end of the day, after appointment hours and before cleaning and disinfection procedures. Samples were collected from the periapical Xray machine (tube head, positioning device, control panel and activator button), the panoramic Xray machine (temporal support, bite block, control panel and activator button), the intraoral digital system (sensor), and the digital system computers (keyboard and mouse). The samples were seeded in different culture media, incubated, and colonyforming units (CFU/mL) counted. Biochemical tests were performed for suspected colonies of Staphylococcus, Streptococcus and Gramnegative bacilli (GNB). Fungi were visually differentiated into filamentous fungi and yeasts. The results indicated the growth of fungi and Staphylococcus from all sampling locations. GNB growth was observed from all sites sampled from the intraoral Xray equipment. On the panoramic unit, GNB growth was observed in samples from activator button, keyboard and mouse. In general, a higher number of CFU/mL was present before use. It can be concluded that more stringent protocols are needed to control infection and prevent Xray exams from acting as vehicle for cross contamination.

O objetivo neste estudo foi avaliar o índice de contaminação dos equipamentos de radiografias digitais intra e extrabucais da clínica de radiologia odontológica de uma instituição pública de ensino. As amostras foram coletadas em três dias distintos, em dois momentos: pela manhã, antes dos atendimentos clínicos, e ao final do dia, após os atendimentos e antes dos procedimen tos de limpeza e desinfecção. As amostras foram coletadas do aparelho de raios X periapical (cabeçote, braço articular, painel de controle e botão disparador); do aparelho de raios X panorâmico (apoio temporal, bloco de mordida, painel de controle e botão disparador); do sistema digital intrabucal (sensor); dos computadores dos sistemas digitais (teclado emouse). As amostras foram semeadas em diferentes meios de cultura e, após incubação, foram contadas as unidades formadoras de colônia (UFC/mL). Testes bioquímicos foram realizados para colônias suspeitas de Staphylococcus, Streptococcus e bastonetes Gram negativos(BGN). Os fungos foram diferenciados visualmente em fungos filamentosos e leveduras. Os resultados indicaram crescimento de fungos e Staphylococcus em todos os locais amostrados. Em relação aos BGN, houve crescimento em todos os locais coletados do equipamento radiográfico intrabucal. No aparelho panorâmico, houve crescimento de BGN apenas no botão disparador, teclado e mouse. De maneira geral, houve maior número de UFC/mL antes do uso. Pode se concluir que é necessário implantar protocolos mais rigorosos de controle de infecção na prática radiológica, evitando que a obtenção de exames radiográficos seja um veículo para contaminação cruzada na FO/UFJF.

Enzymatic hydrolysis of gelatin layers of X-Ray films and release of silver particles using keratinolytic serine proteases from Purpureocillium lilacinum LPS # 876.

Enzymatic decomposition of gelatin layers on used X-ray films and repeated utilization of the enzyme for potential application in silver recovery were investigated using keratinolytic serine proteases from Purpureocillium lilacinum LPS # 876. At pH 9.0, the enzymatic reaction was enhanced by the increase of enzyme concentration or by the increase of the temperature up to 60℃. Under the conditions of 6.9 U/ml, 60℃, and pH 9.0, hydrolysis of the gelatin layers and the resulting release of silver particles were achieved within 6 min. The protective effect of polyols against thermal denaturation was investigated. The presence of glycerol and propylene glycol increased enzyme stability. When the reusability of the enzyme for gelatin hydrolysis was tested, it could be seen that it could be effectively reused for more cycles when glycerol was added, compared with the enzyme without protective agents. The results of these repeated treatments suggested that a continuous process of recycling silver from used X-ray is feasible. Keeping in mind that recycling is (at the present time) needed and imperative, it can be remarked that, in this research, three wastes were successfully used: hair waste in order to produce serine proteases; glycerol in order to enhance enzyme thermal stability; and used Xray films in order to recover silver and PET films.

[Microscopic fungi in the air of film documents depositories].

Microscopic fungi of the studied 5 film documents depositories in Kyiv are presented by 14 species of 8 genera of the division Ascomycota (Chaetomium sp.) and the group Anamorphic fungi (13 species 7 genera). Among the isolated species there are generally accepted active destructors of various products and materials, in particular of a cine-film (A. niger, A. versicolor, representatives of genus Penicillium) and species which are potentially dangerous for the human health (A. fumigatus, A. niger, A. versicolor, Geotrichum candidum, P. expansum, Stachybotrys chartarum). The species A. fumigatus, Chaetomium sp., Cladosporium oxysporum have been identified in the air of film depositories for the first time. An individual approach to identifying species-indicators of microbiological quality of the air in film documents depositories is proposed and discussed.

Infection control in digital intraoral radiography: evaluation of microbiological contamination of photostimulable phosphor plates in barrier envelopes.

BACKGROUND AND OBJECTIVE: The detectors (both solid-state sensors and photostimulable phosphor [PSP] plates) used for digital intraoral radiography cannot be autoclaved, and barriers are typically used to prevent the spread of infection. The aim of this study was to determine the effectiveness of a barrier envelope system for PSP plates. METHODS: Disinfected PSP plates were aseptically inserted into barrier envelopes and placed in a periapical location. One PSP plate was placed in each of 28 patients, and 12 plates in each of 2 volunteers (D.S.M., J.D.W.). After retrieval, each PSP plate was removed from its barrier envelope, immersed in trypticase soy broth and aliquots were plated on trypticase soy agar. Bacterial colonies were counted 2 days later. RESULTS: Fifty-two PSP plates in barrier envelopes were evaluated for contamination. Quality assurance of the PSP plates before clinical placement revealed defects in the integrity of 4 barrier envelopes, caused by forceps-related damage or failure to achieve a uniform seal. These defects allowed substantial contamination. Contamination also occurred as a result of failure to extract the PSP plate from the barrier envelope cleanly. Of the 44 barriers with no obvious defects that were placed by either final-year dental students or a radiologist, only 3 allowed bacterial contamination of the PSP plate. CONCLUSION: Detectors contained in barrier envelopes remain a potential source of contamination. PSP plates must be disinfected between removal from a contaminated barrier envelope and placement in a new barrier envelope. In addition, placement into the barrier envelope should ideally be carried out under aseptic conditions. Finally, the integrity of each sealed barrier envelope must be verified visually before release to the clinic.

An evaluation of microbiologic contamination on a phosphor plate system: is weekly gas sterilization enough?

OBJECTIVE: This study was performed to determine: 1) the rate and source of microbiologic contamination of photostimulable phosphor plates (PSP) in a predoctoral clinic; and 2) whether a combination of weekly gas sterilization and barrier protocols can prevent contamination of PSP plates. METHODS: Fifty plates in clinical use and 25 gas-sterilized control plates were selected for examination. The PSP plates were pressed onto blood agar medium and incubated at 37 degrees C. The number, size, distribution, and variety of resulting colonies were noted. To test whether these bacteria could have come from oral sources, 17 colonies were selected for culture on Mitis-Salivarius (M-S) agar. Those colonies that grew on the M-S agar were Gram stained. RESULTS: Twenty-eight test plates (56%) exhibited growth of bacterial colonies on blood agar. Seventeen of those bacterial colonies were selected for growth on M-S agar, and 13 (76.47%) showed growth, 69% of them gram positive. CONCLUSION: Our results indicate reinforcing standard precautions of infection control for intraoral radiography, and that gas sterilization of plates after each day's clinical use is a potential solution.

Efficacy of three surface disinfectants for dental radiographic films and gloves.

Contaminated radiographic films and gloves may transmit infectious diseases. Objective. To determine whether Pre Sept (NaDC), a sodium dichloroisocyanurate based disinfectant; Bronocide SP (AIP) an alcohol-phenol-iodine disinfectant and polyvinyl pyrrolidine iodine (PVPI) can be used to disinfect radiographic films and gloves. Study design. Radiographic films were contaminated with Candida albicans, Streptococcus mutans, Lactobacilli or saliva and placed in either 0.1, 0.25 or 0.5 NaDC for 1, 2 or 5 min; PVPI for 5 min or sprayed with AIP. Gloves contaminated with C. albicans, S. mutans or Lactobacilli were sprayed with AIP. After treatment the films and gloves were tested for viable microorganisms. Results. A 0.5% solution of NaDC killed all microorganisms after one-minute exposure. PVPI killed 99.8% and AIP spray between 95.8 and 99% of microorganisms. Conclusions. NaDC was the most successful disinfectant in the laboratory and clinical setting followed by PVPI and AIP.

Bacterial survival on radiographic cassettes.

The purpose of this investigation was to report the life span of Escherichia coli, Enterococcus faecalis and Staphylococcus aureus on 3 types of radiographic imaging receptors currently used in diagnostic imaging departments in the United States. Kodak 400 speed, Dupont 400 speed and Fuji computed radiography cassettes were inoculated with the 3 bacteria, then placed in an incubation cabinet and cultured for a period of 2 weeks. All 3 cassettes revealed confluent growth with no noticeable reduction in bacterial numbers for the entire test period. This study verifies that common potentially pathogenic bacteria can survive for prolonged periods on radiographic imaging cassettes. Therefore, effective cleaning regimens are of fundamental importance in controlling and preventing potential nosocomial transmission in the diagnostic imaging department.

Avaliaçäo microbiológica de soluçöes desinfetantes e barreiras protetoras, usadas como meio de controle de infecçäo nos procedimentos radiográficos em Odontologia / Microbiologic study of desinfectant solutions and protector barriers, used for infection control in the radiographic procedures in Dentistry

Essa pesquisa teve como objetivo avaliar, através de testes microbiológicos, a efetividade de soluçöes desinfetantes e barreiras mecânicas usadas para controle de infecçäo durante os procedimentos radiográficos em Odontologia. As soluçöes testadas foram: álcool 70 por cento (p/v); hipoclorito de sódio 1 por cento - liquido de Milton; Germpol Plus - fenóis, as quais foram friccionadas com gazes estéreis durante 30 segundos em ambos os lados dos filmes radiográficos intrabucais Kodak EP-21P e Agfa Dentus M2 Comfort. As barreiras usadas foram: filme de polietileno - LAFRApack; filme de PVC - FACILpack; e sacos plásticos transparentes, pequenos, vendidos a granel. Para os testes microbiológicos foram usados vários meios de cultura, incubaçäo em aerobiose e anaerobiose, e bactérias do tipo Streptococcus mutans, Staphylococcus aureus, Bacillus subtilis e Escherichia coli. Também foi realizado teste com microorganismo menor que as bactérias acima relacionadas, sendo utilizados bacteriófagos (fagos), que têm entre 50 e 70 mm. Com esses vírus de bactéria, testaram-se somente as barreiras...