Cross-contamination and cross-infection risk of otoscope heads.

Adequate disinfection level of the medical equipments should be maintained to prevent cross-contamination between patients. Otoscope specula are usually cleaned and disinfected appropriately after each use by disinfectant solutions. However, since otoscope heads are electrical instruments with irregular inner surface they may still harbor pathogenic microorganisms. According to manufacturers' instructions, otoscope heads can be cleaned externally with a damp cloth and they can be disinfected with aldehydes, tensides, and alcohols. Instrument heads should not be placed in liquids. Alcohols cannot be used on glass surfaces. How often an otoscope head must be cleaned to limit contamination is not well established. This study aimed to determine whether the otoscope heads harbor pathogenic microorganisms or not. A total of 53 otoscope heads were included in the study. Swab samples were obtained from the inner parts of the otoscope heads. For bacteriological examination, cotton swabs were inoculated onto 5 % sheep blood agar, chocolate agar, and eosine methylene blue agar plates. For fungal evaluation, cotton swabs were inoculated onto Sabouraud dextrose agars. Cultured microorganisms were evaluated macroscopically and microscopically. Of the 53 otoscope heads, 22 were found to be contaminated with bacteria and/or fungi. Eleven of them were colonized by one organism, 11 were colonized by more than one organism. Only one Pseudomonas species isolated as gram-negative microorganism. Gram-positive microorganisms were isolated from the remaining 19 samples. Staphylococcus species were the most common bacteria isolated. The most common fungal isolates were Aspergillus species. Two cultures were positive with Candida albicans. The results show that decontamination of the otoscope heads is usually ignored. However, they can harbor considerable amount of pathogenic microorganisms. The probability of contamination and the risk of cross-infection is high if they are used by otolaryngologists. In order to prevent cross-contamination between patients, guidelines indicating appropriate methods and frequency of cleaning and disinfection of otoscope heads needed to be described.

Evaluation of otoscope cone disinfection techniques and contamination level in small animal private practice.

The objective of this study was to evaluate the level of bacterial contamination of otoscope cones in veterinary private practice, and to determine the most effective method of disinfection. Fifty small animal practices participated in this study, which included a detailed survey regarding otoscope cleaning, storage and usage and quantitative culture of the cleaned and stored otoscope cones. Using sterile technique, two cones from each of the 50 hospitals were swabbed and submitted for quantitative culture. Contamination was present in 29% of the samples and the following organisms were isolated: Flavobacterium brevis (10%), Pseudomonas aeruginosa (6%), Pseudomonas alcaligenes (4%), Staphylococcus intermedius (4%), Corynebacterium spp. (2%), Bacillus spp. (1%), Enterococcus faecalis (1%) Malassezia spp. (1%). There was no statistically significant difference between storage type (dry versus stored in solution) and for the instrumentation used to clean the cones (brush, cotton-tipped applicator, both versus none). There was a statistically significant difference between the different cleaning solutions (P < 0.001) and between the storage solutions (P = 0.003). A single most effective cleaning solution was unable to be determined due to the large number of solutions utilized. Cetylcide G (Cetylite Industries, Inc., Pennsauken, NJ, USA) was the most effective of the three most commonly used storage solutions (Cetylcide G, Benz-all, and 2% Chlorhexidine gluconate) when used as directed (P < 0.001). The level of contamination had a positive association with the frequency of cone use and a negative association with the frequency of storage solution replacement.

Evaluation of otoscope cone cleaning and disinfection procedures commonly used in veterinary medical practices: a pilot study.

The objective of this study was to evaluate the relative efficacy of otoscope cone cleaning and disinfection methods commonly used in veterinary practices. Using sterile technique, 60 new gas-sterilized 4-mm otoscope cones were inoculated with a broth culture of 1.5 billion Pseudomonas aeruginosa bacteria per mL then allowed to dry for 10 min. Six study groups of 10 cones each were created. Group 1 served as positive control and received no cleaning or disinfection. Group 2 cones were wiped with sterile cotton-tipped applicators and gauze then rinsed with water. Group 3 cones were wiped with 70% isopropyl alcohol. Group 4 cones were scrubbed in a speculum cleaner with Cetylcide II solution (Cetylite Industries, Inc., Pennsauken, NJ). Groups 5 and 6 cones were soaked for 20 min in Cetylcide II and chlorhexidine gluconate 2% solutions, respectively. Using sterile technique and after 10-15 min drying time, the cones were swabbed in a consistent pattern, and samples were submitted for quantitative culture. Culture results showed no growth from cones soaked in Cetylcide II or chlorhexidine solutions. Two of the 10 cones wiped with alcohol, 3/10 cones wiped then rinsed with water, and 3/10 cones scrubbed with the speculum cleaner showed growth of P. aeruginosa. All (10/10) cones in the control group showed heavy growth of P. aeruginosa. These results show that P. aeruginosa can survive on otoscope cones cleaned and disinfected by several commonly used methods. Further study is needed to determine practical and optimal cleaning and disinfection methods for otoscope cones.

Stethoscopes and otoscopes--a potential vector of infection?

OBJECTIVES: We aimed to determine whether stethoscopes and otoscopes used in community paediatric clinics harboured pathogenic micro-organisms, and, if so, which measures could prevent this. METHODS: Fifty-five stethoscopes belonging to paediatric physicians working in 12 community clinics were sampled for bacterial cultures by two methods: (i) direct impression of the diaphragm and bell section of each stethoscope for 5 seconds onto blood agar plates and a mannitol-salt-agar plate; (ii) swabbing the entire surface of the diaphragm of the stethoscope with a sterile cotton-tipped applicator. Forty-two otoscopes from the same physicians were sampled by rubbing the handles of the otoscopes with cotton-tipped swabs. The plates were incubated at 37 degrees C for 48 hours and examined for colony growth at 24 and 48 hours of incubation. Culture results were recorded as mean numbers of colony-forming units (CFUs). Eight additional stethoscope diaphragms were chosen at random at the participating clinics and cultured as described above. They were then wiped with alcohol swabs (isopropyl alcohol 70%), allowed to air dry for approximately 10 minutes and cultured a second time. RESULTS: All the stethoscopes and 90% of the otoscope handles were colonized by microorganisms. Staphylococci were isolated from 85.4% of the stethoscopes and 83.3% of the otoscopes, with 54.5% and 45.2% respectively being S. Aureus. Methicillin-resistant S. aureus were found in four each of the stethoscopes (7.3%) and otoscopes (9.5%). Cleaning with alcohol reduced the colony count by an average of 96.3%. CONCLUSIONS: Fomites can harbour potentially pathogenic bacteria, and with the increasing trend for children with more complex medical problems to be managed in an ambulatory setting, often by physicians who also work in hospitals, there is a real risk of spreading potentially serious infections to such patients. Simple cleansing with alcohol effectively eliminates the bacterial contamination of the fomites, and should be encouraged.