Risk of Contamination of Nasal Sprays in Otolaryngology Practice

Risk of Contamination of Nasal Sprays in Otolaryngology Practice Abstract Nasal sprays are frequently used in otolaryngological examination, and there is increasing concern about the cross contamination risk of these multi-use sprays. The aim of our study is to determine the safety of these devices by microbiological examination after multiple usage. Nasal sprays were used in nasal physical examination of 282 patients admitted to a tertiary otolaryngology clinic. Two different precaution methods, protective punched caps or rinsing with alcohol are compared with control group. Although there was no statistically significant difference in positive culture rates among the groups, MRSA was isolated in 4 of 198 cultures. Key words: Nasal spray, contamination Introduction Topical vasoconstrictive and anesthetic agents are routinely used in otolaryngology practice. They exert a decongestant and/or local anesthetic action on the mucous membranes of the nasal and pharyngeal cavities. To improve the ease of the examination, and to make the patient more comfortable, these agents are administered before anterior rhinoscopy, flexible fiber optic or rigid endoscopy, or videolaryngoscopy. Devices that deliver topical vasoconstrictive and anesthetic agents typically apply one of two methods to deliver the medication: Venturi or positive pressure principle. The risk of contamination of the medication delivery systems as well as the risk of atomizer-associated cross-infection has been investigated, and controversial results have been reported. Obviously, use of a single-

use atomizer is a definitive (but costly) solution to this problem. In this study, we tried to assess the risk of cross-contamination of multiple-use positive-pressure type nasal sprays, and discussed the literature. Materials and Methods The study consisted of microbiological examination of multiple-dose decongestant nasal spray bottles, used before anterior rhinoscopic or fiberoptic endoscopic examinations of 282 patients admitted to Baskent University ENT clinic during March 2005. Spray bottles contained 0.05% oxymetazoline hydrochloride as vasoconstrictive agent and 0.01% benzalkonium chloride as a preservative (Iliadin plastic spray bottle 10 ml, Merck Ltd, Istanbul, Turkey). Spray bottles were used in two different ways. Caps-off bottles (Figure 1) were rinsed with 70% alcohol solution after each use; caps-on bottles (Figure 2) were replaced with a new clean, punched cap for each patient. These caps were punched to acquire a sufficient hole. Each participating physician used two spray bottles (one cap-on bottle and one cap-off bottle) on several patients at his examination room, during the course of single-day outpatient examinations. For each patient requiring nasal decongestion, medicine was delivered by a cap-on bottle spray through one of the two nostrils. A cap-off bottle spray was used for the other nostril. The nozzle of the spray was inserted loosely into the nostril and squeezed 2 times. The patient was asked to sniff in to ensure even distribution of the spray. In order to assess the risk of contamination from the environment, a third and last spray (control group) was left on the examination table and never used throughout the day. At the end of the day, spray bottles were taken to the microbiology laboratory. Three groups were classified as caps-off bottles (Group 1), caps-on bottles (Group 2), and unused

caps-off controls (Group 3). Each group contained 22 spray bottles, denoting 22 physicianexamination days. Each spray bottle in Groups 1 and 2 was used on a mean of 12±2 patients. The three parts of each spray bottle (the tip, the inner part of the pump, and the fluid remained in the container) (Figure 3) were cultured onto sheep blood, chocolate, and eosinmethylene blue (EMB) agars. The tip of the pump was streaked, and 0.01 ml of the fluid in the pump was inoculated on the agar surfaces. The inside of the pump was rinsed with 1 ml sterile distilled water, and then 0.01 ml of this fluid was inoculated onto agar surfaces to search for intraluminal colonization. Culture plates were incubated for 48 hours. Colonies seen on the agar surfaces were studied further, and the bacterial strains were identified by conventional laboratory methods. The chi-square test and Fisher s exact test were used for statistical analyses. A value for P of less than 0.05 was considered a statistically significant result. Statistical analyses were performed with Epi Info v. 6.0 (Center for Disease Control and Prevention & WHO, Atlanta, Ga, USA) Results Sprays in groups 1 and 2 were used in 282 patients. There were 151 females and 131 males, with mean age of 46.2 years (range, 12-81 years). Each spray was used on an average of 12.8 patients. A total of 198 cultures were performed from 66 sprays during the study. Colonies seen on the agar surfaces were further studied and methicillin-resistant coagulase (-) staphylococcus strains were isolated from all of the 4 positive cultures. All of the positive results were from samples that had been taken from the bottle tips. No bacterial growth was evident in cultures taken from the inner side of the pump. Results of the cultures are presented in Table 1.

There was no statistically significant difference in positive culture rates among the three groups (P > 0.05, x 2 = 3.73). In addition, there was no statistically significant difference between Groups 1 and 2 when the control group was excluded (P > 0.05, x 2 = 0.28). Discussion There are several reports in the literature regarding the risk of contamination of devices that are used for delivering local anesthetic and vasoconstrictive agents in otolaryngology clinics. Atomizers that work via the Venturi principle have been studied; however, the risk of contamination of single-use sprays that work via a positive displacement mechanism has yet to be established (1-10). The Venturi effect is that the velocity of a gas increases as the corridor it passes through narrows. Since the total energy does not change in a closed system, as the velocity (and therefore kinetic energy) of the gas increases, its potential energy falls. The potential energy of a gas is the pressure it exerts; thus, the fall in potential energy will result in a fall in gas pressure. In a venturi atomizer, the Venturi effect causes a negative air pressure and creates a vacuum that results in the suction and flow of the fluid out of the medication reservoir into the medication delivery tube. In 1993, Coakley and colleagues reported that nasal sprays that work on the Venturi principle have the disadvantage of sucking-back, which makes them unhygienic for use in more than one patient (1). They used a dye that sucked back into the lumen of the internal nozzle and even contaminated the fluid that remained in reservoir, and they concluded that atomizers that work on the Venturi principle must be replaced with disposable ones. Wolfe and coworkers used high external concentrations of Staphylococcus aureus in a solution to investigate the internal contamination of Venturi-principle atomizers and positivedisplacement atomizers (2). They reported that external bacterial contamination of the

atomizer nozzle tip results in internal bacterial contamination of Venturi devices even with a single use, but this was not the case in positive displacement devices. Spraggs and colleagues studied Venturi atomizers in 12 healthy volunteers (3). They cultured different parts of the devices and compared the colonies with those from a previously collected nasal swab. Culture results showed transmission of bacteria from the nasal vestibule onto the tip, into the nozzle, and into the reservoir of the atomizer. They stated that the preservatives had poor antibacterial properties. Southwick and coworkers investigated a possible association of cluster of tuberculosis cases with atomizer reuse and concluded that contaminated atomizers may cause tuberculosis transmission (4). In contrast, Visosky and colleagues were unable to demonstrate significant bacterial colonization of multiple-use atomizers in their outpatient otolaryngology clinic (5). The authors studied serial dilutions of multidose-drug solutions in the atomizers to minimize the inhibitory effect of antiseptic agents in drug formulations and reported that only 0.6% of the drug solutions yielded bacterial growth (coagulase-negative Staphylococci). They concluded that when aerosolizing equipment does not directly come in contact with the patient, and the agents that were used contained a bacteriostatic preservative, the use of multiple-use atomizers does not pose a risk of bacterial transmission between patients. Similarly, Scianna and colleagues advocate using an appropriate application technique, stating that continued use of the Venturi-system atomizer is an acceptable practice (6). In our study, 4 (2.02%) of the 198 cultures taken yielded bacterial growth. In all of the positive cultures, methicillin-resistant coagulase (-) staphylococci were recovered from the tips of the sprayers. The lumen of the pump, or the solution that remained in the pump was not contaminated.

Bossart and Wolfe reviewed alternative topical medication applicators that can safely deliver topical medications without risk of cross-infection (7). The authors stated that positive-displacement atomizers with disposable tips offer the ability to deliver an exact dose of many medications in an atomized spray. Several methods for delivering local anesthetic solutions are preferred in different clinics. Some clinicians use disposable tip protectors that fit onto the tips of aerosol equipment. The single-use caps that fit onto the tip of the sprays in Group 2 were designed to prevent direct contact with nasal membranes. In this study, we did not necessarily use a nasal speculum to spread the patients nares; therefore, the tip of the sprays without a cap came into contact with the patients nasal mucosa. The use of a disposable, punched cap seemed to be a practical way to prevent contamination with nasal flora, but one of the 4 positive results was obtained from the spray with a cap. Although there was no statistically significant difference, there were more positive results in sprays without a cap. It is a matter of discussion whether numbers to treat or statistical principles should be used in evaluation of results like this. With the fact that even one transmitted MRSA can cause a huge problem in certain patient groups, we can say that neither of the devices are acceptable. Since, the inner parts of the pump and solutions were not contaminated, replacing the tip with a new sterilized one, after each patient, may be a practical and inexpensive alternative (Sterilization of one tip with ethylene oxide costs around 0.005 (Euros) at our hospital). But the safety of this alternative needs to be proven with further studies. Furthermore, it is impossible to isolate some important pathogens with conventional microbiological culture methods (sheep blood, chocolate, and eosin-methylene blue (EMB) agars), such as M. tuberculosis, viruses or prions. These pathogens also may easily contaminate the devices and play a role in cross-infection.

Although no statistically significant difference was present among our groups, and it is worth conducting further studies with larger groups, bacterial growth was seen in 4 of the cultures. Therefore, the ideal way of eliminating cross-infection, at least for now, is using a new, seperate, and disposable bottle for each patient. In conclusion, every precaution should be taken to minimize the risk of crossinfection from nasal sprays.

References 1. Coakley JF, Arthurs GJ, Wilsher TK. The need for and development of a single use disposable nasal spray. J Laryngol Otol. 1993 Jan;107(1):20-3. 2. Wolfe TR, Hillman TA, Bossart PJ. The comparative risks of bacterial contamination between a venturi atomizer and a positive displacement atomizer. Am J Rhinol. 2002 Jul- Aug;16(4):181-6; discussion 186. 3. Spraggs PD, Hanekom WH, Mochloulis G, Joseph T, Kelsey MC. The assessment of the risk of cross-infection with a multi-use nasal atomizer. J Hosp Infect. 1994 Dec;28(4):315-21. 4. Southwick KL, Hoffmann K, Ferree K, Matthews J, Salfinger M. Cluster of tuberculosis cases in North Carolina: possible association with atomizer reuse. Am J Infect Control. 2001 Feb;29(1):1-6. 5. Visosky AM, Murr AH, Ng V, Dentoni T, Weir L, Haller BL. Multiple-use atomizers in outpatient otolaryngology clinics are not necessarily an infectious risk. Otolaryngol Head Neck Surg. 2003 Apr;128(4):447-51. 6. Scianna JM, Chow JM, Hotaling A. Analysis of possible cross-contamination with the venturi system atomizer. Am J Rhinol. 2005 Sep-Oct;19(5):503-7. 7. Bossart PJ, Wolfe T. Am J Infect Control. 2003 Nov;31(7):441-4. 8. Wolfe TR. The risk of patient cross-contamination from Venturi-Principle atomizers. ORL Head Neck Nurs. 2005 Spring;23(2):25-7. 9. Rizzi M, Batra PS, Hall G, Citardi MJ, Lanza DC. An assessment for the presence of bacterial contamination of Venturi principle atomizers in a clinical setting. Am J Rhinol. 2005 Jan-Feb;19(1):21-3.

10. Dubin MG, White DR, Melroy CT, Gergan MT, Rutala WA, Senior BA. Multi-use Venturi nasal atomizer contamination in a clinical rhinologic practice. Am J Rhinol. 2004 May-Jun;18(3):151-6/

Figure Legends Figure 1. (A) Picture of a spray bottle in Group 1, with its cap off. (B) Picture of a spray bottle in Group 2, with its punched cap on. Figure 2. Different parts of the spray bottle that were cultured (A: Tip of the pump; B: Inside of the pump; C: Inside of the container).

Figure 1

Figure 2

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