IINNTTRROODDUUCCTTIIOONNInfection control in health careinstitutions is the single most importantreason for the prevention of morbidityand mortality associated withnosocomial infections. Hundreds ofthousands of American patients sufferthe consequences of nosocomialinfections each year. Such consequencesrange from the inconvenience of havingto take additional medications fortreating an infection to death. Asidefrom this human cost is the significanteconomic encumbrance that theseinfections place on society, including notonly an apparent increase in health careresource usage but also the indirectcosts associated with the loss ofproductivity of patients and caregivers.1
A facility in which a large number ofpeople having a vulnerable health statusand spending a significant amount oftime in during the course of the day canbe defined as an institutional setting.The time that people spend together inthese settings may be continuous fordays, weeks, or even months. Child carecenters, schools, hospitals, long-termcare facilities (including nursing homesand assisted living centers), militaryinstallations, and prisons are allexamples of institutions. Although theyvary greatly in both the populationinfluences and the length of stay of theparticipants, they all have a commonelement that being because ofconfinement, an opportunity of thetransmission of infectious agents.Therefore, a variety of infection controlpractices are important.2 One third of allnosocomial infections may bepreventable, and they are frequentlycaused by organisms within theinstitutional environment.
Microorganisms associated withinfections manifested in institutionalsettings include bacteria, viruses, fungi,parasites, and nematodes. Transmissionroutes may be direct or indirect contactwith contaminated fomites or air. Onemeans of reducing nosocomial infectionsis to identify previously unrecognizedfomites and then provide some measureof infection control for thosecontaminated objects.
Drug bins used to transport and delivermedications to patients by nurses maybe an unrecognized fomite and maycontribute to the spread of nosocomialinfections in an institution. Pharmacyneeds to be aware of the possiblecontamination of drug bins withmicroorganisms capable of causingnosocomial infection in patients who arecompromised.
With this as a basis, a study wasinitiated in a 300-bed general med/surghospital to investigate the degree ofmicrobial contamination in dirty drugbins and compare this to the use of binliners as an adjunct to minimize thepotential for nosocomial infectionspread.
MMEETTHHOODDOOLLOOGGYYFifty-five (55) drug bins used totransport and administer drugs topatients in a 300-bed general med/surghospital were sampled for bacterialgrowth.
The drug bins were randomly sampledon medication carts on three activehospital units. Thirty (30) randomsamples were taken from a generalmed/surg unit. Fifteen (15) randomsamples were taken from a MICU unit.Ten (10) random samples were takenfrom a surgical unit.
Twenty-five (25) bin liners were sampledfrom a batch of prototype linersprovided by Health Care Logistics to thehospital. A similar procedure was usedin the sampling of both the drug binsand bin liners.
A hospital lab microbiologist using S/PBrand Culture Swab Collection andTransport System, distributed byAllegiance Healthcare Corporation,Catalog Number C8552-11 moistenedwith non-bacteriostatic saline wetswabbed both the drug bins and binliners and streaked both blood agar andEMB (eosin methylene blue) plates.
Plates were incubated at 35˚ C andexamined for growth at 24, 48, and72 hour intervals.
The cultures were identified by standardmeans and reported and categorized.The blood agar plates werephotographed for a visualdocumentation of therelative amount of bacterial growth.
RREESSUULLTTSSOverall, 84% of all the drug bins thatwere tested were contaminated withbacterial and mold growth asdetermined by the test swabbingprocedures. In contrast only 32% of thebin liners cultured were contaminatedwith bacteria and mold growth.
Of the 84% of the drug bins that werecontaminated 28 bins (50%) showedpositive for 1 organism, 14 bins (25%) for2 organisms and 5 bins (9%) for 3organisms. Nine bins (16%) showed nogrowth. [see Table 1 below for organismcount in sampled drug bins]
Of the 32% of the bin liners that werecontaminated 6 liners (24%) showedpositive for 1 organism, 1 liner (4%) for 2organisms and 1 liner (4%) for 3organisms. Seventeen bin liners (68%)showed no growth. [see Table 2 belowfor organism count in sample bin liners]
Comparably fewer bin liners werecontaminated than drug bins.
Coagulase negative staph was thecommonest contaminant found with 62%of drug bins contaminated with thisorganism alone or in combination withother bacteria or mold. Pseudomonaswas identified in one drug bin incombination with coagulase-negativestaph and penicillium. Other bacteriafound include diphtheroids and bacillusin combination with staph coagulase-negative or by itself. Mold growthconsisted of alternaria, cladosporium,penicillium and one that was notidentified. Again, mold growth was incombination with other organismsor by itself. [see Table 3 below for abreakdown of organisms in thecontaminated bins]
Identification of the representativecolonies showed that most of theorganisms cultured were associated withnormal human skin microflora andenvironmental contamination. Althoughmost microorganisms identified weregenerally harmless environmentalcontaminants, some such as thecoagulase-negative staph andpseudomonas are capable of causingserious infections. Patients who arecompromised by AIDS or bytransplantation or cancer therapy, andpatients with an increased susceptibilityto infection as a result of diabetes orsevere burns are particularly at risk.
In contrast, bacillus was the commonestcontaminant found in 9% ofcontaminated bin liners either alone orin combination with other bacteria ormold. Other bacteria found includediphtheroids, staph coagulase-negative.Mold growth consisted of cladosporiumand one that was not identified. Again,mold growth was in combination withother organisms or by itself. [see Table 4below for a breakdown of organisms inthe contaminated bin liners]
Table 4: Breakdown of organisms incontaminated bin liners
Organism # of bins %
DDIISSCCUUSSSSIIOONNThe results of this study identify animportant problem - that being - a highlevel of contamination on drug binscirculating in the institution. Thepresence of nonpathogenic members ofthe skin and environmental bacteria, inrelatively high numbers, indicates thispoor degree of cleanliness. Dirty drugbins may be a source of transmission ofdrug-resistant pathogens and shouldundoubtedly receive more emphasis ininfection control programs. Onewonders whether such high levels ofcontamination are acceptable in theinstitutional pharmacy setting.
Although there is no direct proof thatmicroorganisms from dirty bins cancause nosocomial infections in patientsor pose a threat to health care workers,a strong and obvious relationship can bedrawn from the results of this studywhich suggests that contaminated dirtybins could contribute to the nosocomialinfection rate.
The CDC recently stated that contacttransmission - direct from body surfaceto body surface or indirect transmissionvia contaminated inanimate objects isone of the main sources ofmicroorganism transmission.3 Onenvironmental surfaces, like drug bins,both the presence of pathogenicmicroorganisms and their abilityto survive on the surface of the bin, cancontribute to the risk of infection.
Studies have established the persistenceof pathogenic microorganisms and theirsurvival in institutional, commercial, anddomestic settings. The potential forinfectious disease transmission from theenvironment is further demonstrated byclinical and laboratory studies showingthe transmission of microorganismsfrom person-to-person and via inanimatesurfaces, water, hands, food andhousehold surfaces.
Studies have shown that the inanimateenvironment may serve as a reservoir-disseminator of MRSA and nosocomialVRE transmission. Positive cultures havebeen isolated from infectious patients'rooms and on gloves, gowns, anduniforms of nurses contacting thepatients and also in 42% of personnelnot in direct contact with patients butthrough contamination of their gloves bytouching contaminated surfaces. 4
Furthermore, studies have shown thatboth bacteria and fungi can live forextended periods of time on plastics 5-8
and microorganisms can efficiently betransferred from plastics to humanhands.9 In turn, a number of studies,often associated with the value ofhandwashing, have indicated thatmicroorganisms can be transferred fromperson to person or from health careworkers to patients.10-12
Contamination in dirty drug bins withpotentially pathogenic bacteria,especially MRSA, has the potential fortransmission to a larger number ofhealth care workers. Theoretically,contaminated drug bins might pose anunsuspected source of transmission ofnosocomial pathogens to health careworkers and other patients throughoutthe institution.13 These bacteria aretransmitted to the hands of the healthcare worker (usually the nurse) andcould subsequently be transmitted toother patients in the course of task ofadministering medications.Because of the increased risk that dirtybins could present to patients, the use ofthese containers throughout a hospitalwithout some sort of cleaning protocolshould be reviewed.
A wide variety of patients, from neonatesto elderly, are present in the institution.Certain groups such asimmunocompromised or those at theextremes of life may be more prone tonosocomial infection. Awareness inpharmacy of the potential for a dirtydrug bin to be the source ofcontamination is critical to soundpractice.
While the sample size was small and theresults of this study need to beconfirmed with a larger sample size,clearly the dirty bins harboredsignificant numbers of bacteria,probably because the difficulty incleaning them, lack of cleaning orneglect of cleaning.
Therefore some options should beconsidered to reduce the possibility oftransfer of microorganisms from theplastic infectious dirty bins to patients.Two such options are:
11.. TThhee IInniittiiaattiioonn ooff aa BBiinn CClleeaanniinngg PPrroottooccooll
The cleaning of dirty bins is generallyignored in day to day practice. Througha series of discussions with hospitalpharmacists and a small surveyconducted at a midwestern statehospital pharmacy meeting, it wasdetermined that no formal bin cleaningprotocols exist in pharmacy. Instead, bincleaning was initiated on either anindividual circumstance where a bin wasdirty beyond use or when a regulatorybody was going to present itself at theinstitution.
In most cases there is a lack ofawareness of a problem with respect todirty drug bins and spread ofnosocomial infections. Changingpharmacist and nurse behaviors isprobably the greatest challenge inaddressing this problem.
Health benefits from environmentalsurface disinfection have beendemonstrated in several studies.Cleaning studies have indicated that thedisinfectant-cleaner routinely used toclean surfaces in patient roomsdecreases the microbial load.One canassume that use of a disinfectant-cleaneron drug bins will also decrease themicrobial load. Ideally dirty drug binsshould be cleaned on a regular basis,perhaps upon patient discharge,irrespective of their appearance.Dirty drug bins should be washed withdisinfectants in automatic washingmachines - however, this in manyinstitutions turns out to be impracticaland unwieldy.
Effective cleaning management requiresa correctly constructed, implemented,and monitored cleaning program. Arecent study concluded that visualassessment is a poor indicator ofcleaning efficacy and that an ACE audit(Audit for Cleaning Efficacy) gives abetter assessment of cleaning programs.
It recommends that hospital cleaningregimes be designed to ensure thatsurfaces are cleaned adequately and thatefficacy is assessed with use of internalauditing and rapid hygiene testing. Itrecommends that after cleaning hastaken place, measurements (visual, plusadenosine triphosphate [ATP] ormicrobial) should be obtained to ensurethat the cleaning has been carried outcorrectly or to an appropriate standard.Data from monitoring should be retainedand used in trend analysis andcompared with benchmark values thathave been obtained during thevalidation of the cleaning program. 14
Bin cleaning is often dependent on staffmotivation and the time they are givento do this task. The result is irregularand inadequate cleaning of bins, whichis often a source of dissatisfaction toboth pharmacy and nursing personnelthat encounter dirty bins. Adding thisprocedure during the regular cart fillingtasks of pharmacy can potentially addcost to the process.
In a formal bin cleaning protocol, thetask of cleaning should be undertaken bya designated and fully informedpharmacy staff person whom shouldtake all necessary precautions. Thoseresponsible for the cleaning should beprovided with some protective clothing,such as gowns, gloves and goggles. Itshould be noted that repeated washingof bins will decrease their lifespan andpotentially make them more susceptibleto microbial growth. Bins will be in needof regular and on-going replacement.
Overall, though bin cleaning is an optionthat would be an effective interventionto minimize spread of nosocomialinfections potentially caused by dirtydrug bins - bin cleaning is costly, time-consuming and potentially harmful topersonnel performing the cleaning andto the integrity of the bins over time.
22.. TThhee UUssee ooff BBiinn LLiinneerrssBin liners on the other hand are a usefuland practical alternative. The use of binliners as an intervention to minimize thespread of nosocomial infections is asecond option. They improve patientcare by providing a more consistent,convenient and cost-effective method ofmaintaining clean patient medicationdrawers and medical storage bins.
A bin liner is a lightweight polystyreneplastic tray with dimensions slightly lessthan that of a drug bin that fits into thedrug bin covering and shielding itsinside surface. This shielding of theinside surface of the drug bin protectsthe drug bin itself from dirt and residuethat can harbor potentially dangerousmicroorganisms.
A bin liner replacement program caneasily be implemented as a procedureduring the regular cart filling tasks ofpharmacy. Bin liners can be replaced ona regular basis upon discharge of apatient with the new liner being assignedto a newly admitted patient. Whenever abin liner becomes soiled it can bedisposed of and replaced with anotherclean liner. This could be accomplishedboth in the pharmacy and up on thenursing unit. No cleaning is required.When compared to a bin cleaningprotocol the bin liner replacementprogram is clearly easier to implementand maintain.
Though exhibiting a lowercontamination rate bin liners onlyminimize microbial growth but do noteliminate it. Bin liners are subjected tothe same conditions that the bin is. Thedifference is that - once dirty - the binliner can be easily and quickly replacedwith a new and clean bin liner whereas adirty bin needs to be put through acleaning process.
SSttuuddyy LLiimmiittaattiioonnssThe bin liners cultured in this studyshowed a contamination rate of 32% incomparison to the 84% contaminationrate of the dirty bins. It should be notedhere that the bin liners used in thisstudy were prototypes and not unitsfrom a fully manufactured batch. Assuch, handling precautions were notinitiated to package these prototypes inplastic bags of 25 as the production ofsales batches will be packaged. Also,these prototypes were subjected toexcessive handling from themanufacturer to distributor and on tothe study site (hospital) where the studywas conducted. In this process they mayhave been contaminated.
Although the dirty bins cultured in thisstudy were not contaminated withlifethreatening nosocomial pathogens,84% of the dirty bins were contaminated.No overt attempt in this study was madeto culture bins of patients withprescribed contact precautions forMRSA or VRE. Though none of theseserious pathogens showed up in thisstudy the potential exists forcontamination of these organisms indirty bins.
CCLLOOSSIINNGGThis study makes no attempt to assessthe risk of acquiring an infection from adirty drug bin. No follow up wasincluded to assess if any patientinfection resulted from thiscontamination. The study, however,sought to discover if there is a potentialsource from which an infection coulddevelop and suggest ways inwhich this source can be minimized.This study suggests that regular cleaningof bins or use of bin liners betweenpatients should be considered.
Additional studies are needed todetermine the identification andtransmissibility of nosocomial pathogensthrough use of dirty drug bins. In furtherstudies, more defined criteria should beset for the numbers of colony formingunits that constitute a clean bin versus adirty bin. Studies should also be initiatedto determine the effectiveness of a bincleaning protocol.
Ample infection control data in theliterature demonstrate the cost-benefitof departments that have aggressivelypursued interventions to decreasenosocomial infections.15 In comparisonwith other widely accepted preventivemedical interventions, infection controlis recognized as very cost-effective.Reducing nosocomial infections is aproven method to decreaseunreimbursed resource utilization andimprove patient care and safety.16
The prevention of pain and suffering ofpatients and improvements in qualitypatient care are obvious additionalbenefits to the institution and itsreputation, which are difficult toquantify. Charges such aslaboratory/microbiologic costs,antibiotic costs, pharmacy costs, IVcosts related to the delivery ofantibiotics, and increased length of staycaused by nosocomial infections can bequantified. On the basis of the potentialfor these additional costs, the use of binliners as a cost-effective strategy for thereduction of nosocomial infections andimprovement of patient care in theinstitution makes sense.
Bin liners dramatically reduce thebacterial contamination of drug bins.The results of this initial study shouldhighlight their value in an institutionalsetting.Bin liners employed as a strategyto reduce nosocomial infections in theinstitution help improve compliancebecause they are convenient, quick touse,and low cost in comparison to a bincleaning program. Consequently, use ofthese products as part of an infectioncontrol program/strategy for pharmacycan have a significant impact on bothhealth outcomes and health care costs.
Although it is recognized that not allnosocomial infections are potentiallypreventable, more could be preventedwith an active intervention-basedinfection control program. Thecontinued emergence and controldifficulties with multidrugresistantpathogens, such as methicillin-resistantS aureus, vancomycin-resistantenterococci, and extended spectrumbeta-lactamase producing gram negativebacilli, are major problems in acute careand long-term care facilities alike.
Quality of care and patient safety is theobjective of every health careprofessional. Infection controlinterventions contribute to both patientsafety and quality of care. The use of binliners as an infection controlintervention is pharmacy's contribution.
DDEEFFIINNIITTIIOONNSSAAlltteerrnnaarriiaa - a genus of fungi; mostcommon species found in a variety ofhabitats and ubiquitous agents of decay;as decomposers of foodstuffs contributeto spoilage of 20-40% of agriculturaloutput; some alternaria species aregaining prominence as emerging humanpathogens, particularly inimmunocompromised patients; havebeen found associated with infections ofthe cornea, oral and sinus cavities,respiratory tract, nails and skin.
BBaacciilllluuss - aerobic rod-shaped spore-producing bacterium; often occurring inchainlike formations; a variety ofbacterium; a microscopic, rod-shapedvegetable organism; a class of bacteriawhich are rod-shaped. Belonging to thisclass are: E. coli, Salmonella, Shigella,Klebsiella, Enterobacter, Clostridia; ofthese, Bacillus Calmett-Guérin isadministered for vaccination againsttuberculosis; bacteria causing tetanus,diphtheria, pertussis, and tuberculosisare also rodshaped.
CCllaaddoossppoorriiuumm - a genus of fungi havinggreenish conidiophores with oval orround spores; some species causesuperficial fungal infections of the skin ofthe palms.
DDiipphhtthheerrooiidd - pseudodiphtheria; falsediphtheria; one of a group of localinfections, suggesting diphtheria, withoccasional symptoms of toxemia, causedby various microorganisms other thanthe diphtheria bacillus.
FFoommiittee - An inanimate object which,when contaminated with a viablepathogen (bacterium, virus, etc.) cantransfer the pathogen to a host; anyinanimate object (as a towel or money orclothing or dishes or books or toys etc.)that can transmit infectious organismsfrom one person to another
MMoolldd - a fungus that produces asuperficial growth on various kinds ofdamp or decaying organic matter
PPaatthhooggeenn - any disease-producing agentespecially a virus or bacterium or othermicroorganism; any disease-causingagent, such as a virus or bacterium;Definition: Organism which can causedisease in another organism.
PPeenniicciilllliiuumm - a saprophytic mold, agenus of the fungi of the classascomycetes, order aspergillales; theyform blue molds which grow on fruits,bread, cheese, etc. Occasionally in manthey produce infections of the externalear, skin, or respiratory passageways;common allergens.
PPsseeuuddoommoonnaass - a genus of small, motile,gram-negative bacilli with polarflagella. Most are saprophytic living insoil and decomposing organic matter;sometimes pathogenic (aeruginosa) inman causing urinary tract or earinfections.
SSttaapphhyyllooccooccccuuss - spherical gram-positiveparasitic bacteria that tend to formirregular colonies; some cause boils orsepticemia or infections;Definition: Staphylococcus is a genus ofspherical, facultatively anaerobic,Grampositive bacteria in the familyMicrococcaceae; they cause a widerange of skin and systemic infections.
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