A MICROBIOLOGICAL SURVEY INTO THE PRESENCE OF CLINICALLY SIGNIFICANT BACTERIA IN THE MOUTHPIECES AND INTERNAL SURFACES OF WOODWIND AND BRASS MUSICAL INSTRUMENTS.
University of Newcastle upon Tyne UK
Author: Christopher Woolnough-King
1994-1995

 

 

 

Introduction

 

Music teachers and players of brass and woodwind instruments are well aware that mouthpieces, internal surfaces and tubing accumulate a great deal of detritus.  Although musicians are aware of the matter build-up within their instruments, most seem oblivious that this material might provide an excellent breeding sight for potentially harmful microorganisms.  Indeed, most musicians are quite content to put mouthpieces containing this organic matter into their mouth and suck in air through the tubing.  Furthermore, a fast method of clearing saliva from woodwind reeds and preventing the degradation of sound quality due to the accumulation of saliva is to suck hard in a short burst.  Air passing over the inanimate surfaces is likely to be a vehicle for the dissemination of propagules that are contained in droplets.  The players interviewed during the present investigation were not unduly worried that their instruments might harbour organisms that could, for example, cause sore throats or lung disease.  An article published in the British Medical Journal has shown that the rapid spread of tuberculosis within the ranks of a military band, through the sharing of instruments was not implicated in this instance.  (Protheroe, 1957).  The rapid dissemination of Mycobacterium tuberculosis from person to person was partly attributed to colonised dust particles spread in a pattern suggesting particle emanation from the instruments.

Music teachers and pupils can be forgiven for their lack of knowledge of the potential health hazards since very little research has been carried out over the past forty years on the microbial contamination of musical instruments.  Most research concerning inanimate surfaces has centred on clinically significant pathogenic viruses, notably the human immunodeficiency virus, HIV, (Lewis et al, 1992).  Study of bacterial colonisation or persistence of microorganisms on general surfaces (Ayliffe, 1991), surgical and dental invasive instruments (Lewis, 1992), and devices such as endoscopes and latex gloves (Vesley et al, 1992; Rutala et al, 1993) have been conducted to demonstrate the extent of microbial persistence so as to apply effective disinfection and sterilization techniques (Mbithi et al, 1993; Rutala et al, 1993).  The underlying strategy is to prevent transmission via these surfaces in environments such as hospitals or dental practices.

Musical instrument mouthpieces can be regarded as invasive implements and as such might be implicated in the transmission and spread of disease.  This might occur either by a), direct contamination of the mouthpiece and tubing; b), airflow from the respiratory tract whilst the instrument is played; c), nasal contamination of fingers and hands, which may then, in turn, contaminate the mouthpiece, or d), the sharing of instruments.

A study that focused on the bacterium Staphylococcus aureus demonstrated an association between nasal colonisation and hand carriage of the organism with subsequent inoculation via the hands (Wenzel, 1994).  Indeed it has been shown that 50% to 75% of the population have asymptomatic colonisation by Staphylococcus aureus of the anterior nares (Sleigh & Timbury, 1994).  It is probable that this route has implications for instrumentalists who might easily contaminate their mouthpieces via hands and/or fingers.

When brass or woodwind instruments are played repeatedly, large amounts of organic matter can quickly build up within the mouthpieces and tubing.  These sites, in particular the tubing where the environment is not as susceptible to drying, are excellent localities for the growth of microorganisms because mouth commensals can easily spread to these sites when the instruments are blown.  In addition, epithelial debris and food particles suspended in saliva provide nutrients.  These environments also offer protection against desiccation.

Investigations by Bottone et al (1994) on natural exfoliative devices such as plant and animal sponges, and on inanimate devices such as pumice stone and synthetic sponges, in the absence of food substrates, showed that they supported microbial growth.  Skin trapped within the interstitial spaces of sponge or pumice stone was sufficient to maintain microorganism viability.  A comparison between these environments and musical instrument mouthpiece surfaces can be envisaged.  This is because epithelial cells and food particles would maintain bacterial growth until either water or nutrients became limiting.  This said, many instrumentalists cleanse their mouthpieces infrequently and inadequately and the inner tubing rarely.

The surface material of mouthpieces and instrument tubing is also a factor that can affect colonisation by microbes.  Microorganisms, for example staphylococci, are able to attach to hydrophobic surfaces of plastic and ebonite, both of which are used in the manufacture of saxophone and clarinet mouthpieces.  The specificity of attachment conforms to the DVLO theory and is accomplished via bacterial fimbria which bring the organism into close proximity to the hydrophobic plastic structure at the molecular level.  Some of the woodwind instruments examined during the course of this study possessed synthetic mouthpieces; the brass instruments and one saxophone possessed metal mouthpieces and the oboe mouthpiece was constructed from two identical symmetrical wooden reeds bound together to form the vibrating structure.  Colonisation of synthetic mouthpieces might be expected to be more widespread than those manufactured from steel.

Microbial growth on a range of metallic surfaces has been studied, and the effect of copper derivatives such as those used in the manufacture of fungicides used for wood preservation has been exploited.  Silver compounds in the form of silver nitrate are also antimicrobial and utilised for topical application in burns cases (Russel, 1960) and to prevent conjunctivitis caused by Neisseria gonorrhoeae infection via vertical transmission to the newborn.  In Canada, laboratory experiments (Gregory et al., 1967) established that the bacteria Serratia marcescens and Streptococcus pyogenes, which were present transiently in seeded wine, died at a faster rate when contained within a silver vessel such as a communion cup.  Instrument metal mouthpieces are usually manufactured from chrome, gold plated brass or stainless steel.

During an investigation such this, an account should be taken of instrument use and cleansing frequency, and ideally, the method and the type of disinfection regime.  Sterilisation (destruction of all organisms including spores) or disinfection (destruction of most organisms) of internal surfaces, carried out by the instrumentalist from time to time, would undoubtedly decrease the microbial load.  However, the disinfecting chemicals are not likely to persist, so the instrument would soon be recontaminated upon reuse.  It is likely that the effects of desiccation would have a greater influence on microbial persistence than infrequent cleansing regimes.  This factor could be expected to greatly influence the number and type of organisms sampled at sites liable to drying.

Agents commonly used to clean instrument tubing and mouthpiece surfaces include: a), TCP (halogenated phenols in aqueous glycerol solution) which is effective against Gram-positive and Gram-negative bacteria but not against spores at ambient temperatures, and b), chlorine releasing agents (Morris, 1971) such as hypochlorites (household bleach) which are effective against a wide microbial spectrum and are also sporicidal.  However, these agents are not especially effective against mycobacteria.  It is notable that the use of chlorine-based agents would attack metal instrument tubing and mouthpieces hence are not entirely suitable for this purpose.  Surface acting agents, for example, surfactant detergents can be used to clean musical instruments (Brown, 1975).  Non-anionic surfactants act by affecting the permeability of Gram-negative cell outer membranes that results in cell lysis.  In low concentrations, anionic surfactants are not antimicrobial but at high concentrations they can also induce cell lysis of Gram-negative bacteria (Salton, 1968).  These surfactants work by initially causing potassium ion (K+) leakage across cytoplasmic membranes and then by loss of the proton motive force.  The efficacy of the methods and the type of chemicals used during cleansing regimes could affect the microbial load at the sample sites.

Concern about potentially pathogenic microorganisms on inanimate surfaces liable to be in close proximity to the human mouth and nose resulted in a microbiological survey of public telephone handsets (Hughes & Hughes).  On conclusion of this study, the investigators announced that these surfaces represented “without a doubt a potential source of infection" and that "disinfection has to be carried out frequently with a formulation capable of giving sustained protection”.

During the course of a feasibility study (Woolnough-King, 1994, unpublished), it was shown that members of several bacterial genera and yeasts could be isolated from instrument mouthpieces and internal inanimate surfaces.  This observation could, of course, be expected from recently played instruments owing to the transfer of oral commensals via the passage of air from the respiratory tract, nasal cavity, naso-pharanyx and buccal cavity.  Organisms, together with epithelial cells are therefore deposited inside the musical instrument.  Microbes were also isolated and cultured from swabs taken from rarely used instruments and from dry organic matter that lined a clarinet mouthpiece and a euphonium mouthpiece, both of which had not been used for several months.  This feasibility study was carried out on instruments from the Music Department at St. Anthony's School For Girls in Sunderland, Tyne & Wear, England.  The instruments mentioned were available for use by the pupils.  During the present study at the St Anthony’s Music Department, it was hypothesised that the sharing of instruments might lead to person-to-person colonisation and possible onset of disease.  The departmental music teacher expressed concern that diseases such as glandular fever might be spread amongst pupils in this way.  This proposition leads, naturally, to suspicion that cold sores, the visible result of Herpes simplex virus Type 1infection, might be similarly passed from person to person.  This route of transmission (via shared instruments) is entirely plausible because direct transmission of saliva is the principal mode of spread of Herpes Simplex Virus Type 1 (HSV-1) (Bennison, 1985).  Epidemiological studies have shown that between a quarter, and a half of the population studied, suffered from recurrent cold sores (Herpes Labialis) (Rawles & Campione-Piccardo).

Glandular fever is caused by the Epstein-Barr virus (EBV), which is also disseminated via saliva.  In Great Britain glandular fever is known as the 'kissing disease' owing to it's high infectivity via intimate kissing between young adults (Bennison, 1985).  The indirect transmission of EBV via inanimate objects such as children`s toys has also been implicated (Bennison, 1985).

Although viral passage was not investigated during this project, bacterial transmission via this route is entirely conceivable.  Neisseria and Corynebacterium strains, in addition to those already mentioned, are potential pathogens that might be transmitted via instrument mouthpieces due to their presence as naso-pharyngeal commensals.  Consequently, if for example, an instrument had been colonised by group A β haemolytic streptococci, exposure of the organism, carried in the airstream during inhalation whilst playing, might colonise the player and result in tonsillitis or at least, sore throat.  Indeed, the music students at Newcastle University, Newcastle-upon-Tyne, England who took part in this survey, suffered from frequent sore throats.  During the course of the four-week sampling period, several of the subjects had either had a sore throat or some other associated clinical symptom.

One of the more unusual organisms that might possibly be contracted by playing a contaminated instrument used by a colonised individual is Treponema, the causative agent of syphilis.  The organism can be transmitted orally (Grim, 1953).  The Grim investigation showed that children presenting with primary mucosal lesions of the mouth had all previously imbibed water from a long pipe called an 'ibrik'.  The comparison to musical instrument mouthpieces is obvious.  Solace may be taken in the fact that syphilis is readily curable in the UK.

 

During the course of this survey, four major experiments were conducted followed by an additional fifth supplementary experiment.  The purpose of the first four experiments was to

 

a), assess whether target organisms were present in the upper respiratory tract of the subjects,

b), investigate whether these had been transferred and had persisted in their instrument mouthpieces,

c) study whether specific species from the target genera, Staphylococcus and Streptococcus, show preference to these environmental privilege sites and

d), investigate variance in species colonisation over the four week sampling period.

 

Isolates obtained during the sampling regime were identified using the tables from Cowan & Steel's Manual for the Identification of Medical Bacteria (Barrow & Feltham, 1993) and the computer program, Bacterial Identifier (Bryant, 1991).  The second and third stage identification tables contained within the Manual for the Identification of Medical Bacteria have recently been updated to reflect recent taxonomic advances made possible using sophisticated techniques such as DNA/DNA pairing.  These methods have enabled more accurate classification of Staphylococcus species.  The presumptive identifications were checked by examining representative strains using Curie point pyrolysis mass spectrometry (PyMS; Magee, 1993).  The development of the PyMS series of automated instruments has not only superseded their predecessor, pyrolysis gas chromatography (PyGC), but has culminated in the development of the inherently more reliable RaPyD 400X machine (Horizon Instruments, Heathfield, Sussex, England).  This state of the art instrument proved to be an invaluable tool for accurate identification and classification of isolated microorganisms.

Pyrolysis mass spectroscopy techniques are based upon the thermal degradation of the sample in a vacuum: thermal intramolecular vibrations fragment the substrate into low molecular weight volatile organic compounds, the pyrolysate.  The pyrolysate gas is then drawn into an expansion chamber and directed towards an ion source whilst simultaneously heated to a temperature between 1000˚C to 1400˚C.  This process prevents condensation.  The gas is then bombarded by electrons, which result in the production of charged molecular fragments.  These fragments are then separated by a quadrupole mass filter which separates ions on the basis of their mass:charge ratio.  These ions now pass to an electron multiplier for counting.  The resultant mass spectrum and ion counts are then archived in digital form in a computer file for future analysis using specially developed software.  Comprehensive reviews on the technique are available (Gutteridge, et al., 1995; Magee, 1993; Magee, 1994).

 

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