Cross-contamination and cross-infection risk of otoscope heads

Abstract

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 on contamination by Malassezia pachydermatis

“…[21][22][23] OCs are instruments with irregular inner surface that may harbor pathogenic microorganisms. 5 According to manufacturer's instructions, OCs can be cleaned externally with a damp cloth and they can be disinfected with aldehydes, surfactants, and alchohols. 5,24,25 In human medicine, a previous work evaluated 53 OCs by sampling for microbiological evaluation and 22 were found to be contaminated with bacteria and/or fungi.…”

“…Since OCs are reusable equipment, they can be mechanical carriers of cross-contamination and cross infection between patients. 1 OCs are in contact with the integument of the ear canal and thus may be easily become contaminated with a variety of microorganisms. 2 The human medical literature supports the concern for potential iatrogenic inoculation of bacteria into a susceptible ear canal, if cleaning and disinfection are unappropriated.…”

“…2 The human medical literature supports the concern for potential iatrogenic inoculation of bacteria into a susceptible ear canal, if cleaning and disinfection are unappropriated. [3][4][5] In veterinary medicine, a wide variety of bacteria and fungi may be isolated from the canine ear canal and include for instance: Staphylococcus pseudintermedius, Streptococcus spp. Pseudomonas spp., Proteus spp.…”

“…14 There is a concern that OCs could serve as a carrier for the spread of infection. [2][3][4][5] The chemical composition of the host epidermis, including the ear canal, seems to play a pivotal role in influencing the pathogenic or commensal phenotype of Malassezia yeasts by selecting different genetic populations with specific physiological requirements, different cell wall compositions, and different antifungal susceptibility profiles. [15][16][17] There is still little indication about the survival time of M. pachydermatis , 1 but the persistence of other yeasts, such as Candida glabrata, was described to be around 5 months or may be shorter like in the case of Candida parapsilosis, 14 days.…”

Flashlight contamination and effectiveness of two disinfectants in a stomatology hospital

“…Microorganisms on a fomite, which may remain viable for days or months, could be transmitted among patients and hospital personnel [3]. Several studies have demonstrated the bacterial contamination of non-critical medical devices (NCMDs), such as otoscopes, white coats, pens, goggles, and other surfaces [3], [4], [5], [6], [7], [8]. In China, the flashlight is a basic NCMD for healthcare workers.…”