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American Journal of Infection Control xxx (2014) 1-3

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American Journal of Infection Control

journal homepage: www.aj ic journal .org

American Journal of Infection Control

Brief report

Bacterial contamination of medical devices in a Greek emergencydepartment: Impact of physicians’ cleaning habits

Eleftheria Fafliora MDa, Vasileios G. Bampalis MD a, Nikolaos Lazarou MDb,George Mantzouranis MD c, Evangelos D. Anastassiou MD, PhD d, Iris Spiliopoulou MD,PhD d, Myrto Christofidou MD, PhD d,*aDepartment of General Practice, University Hospital of Patras, Patras, GreecebDepartment of Internal Medicine, University Hospital of Patras, Patras, GreececDepartment of General Practice, General Hospital of Mesologgi, Mesologgi, GreecedDepartment of Microbiology, School of Medicine, University of Patras, Patras, Greece

Key Words:StethoscopesMicroorganisms loadUniversity hospital

* Address correspondence to Myrto ChristofidouMicrobiology, School of Medicine, University of Patra

E-mail address: christof@med.upatras.gr (M. ChrisFunding for this work was provided by the Depart

of Medicine, University of Patras.Conflicts of interest: None to report.

0196-6553/$36.00 - Copyright � 2014 by the Associahttp://dx.doi.org/10.1016/j.ajic.2014.03.017

We investigated the bacterial contamination of physicians’ stethoscopes, electrocardiography machines,cardiac monitors, and pulse oximeters, as well as physicians’ self-reported cleaning habits in theemergency department of a university hospital. Among 100 devices evaluated (stethoscopes included),99% developed a positive bacterial culture. Coagulase-negative staphylococci predominated (80.3%). Only13% of physicians reported cleaning their stethoscope after each patient examination; multinomialregression analysis found less contamination on those stethoscopes (P < .001). Studies on the imple-mentation of hygiene measures are needed.

Copyright � 2014 by the Association for Professionals in Infection Control and Epidemiology, Inc.Published by Elsevier Inc. All rights reserved.

Hospital-associated infections (HAIs), defined as infectionsacquired during hospitalization and not present or incubating atadmission, represent one of the leading causes of death, withconsiderable associated economic costs.1 Factors related to themicrobial agent, the patient’s clinical status, the environment,and the widespread use of antimicrobials contribute to theemergence and expansion of HAIs.1 Concerning the environment,the contamination of objects and devices by microbial flora mayplay an important role.1 Stethoscopes, white coats, and othersurfaces have been shown to yield significant bacterial contami-nation.2-6

The primary objective of the present study was to determinewhether physicians’ stethoscopes and other medical devices in anemergency department (ED) harbored bacteria. A secondaryobjective was to survey the physicians’ self-reported cleaninghabits and evaluated whether these practices are associated withthe stethoscope contamination.

, MD, PhD, Department ofs, 26500 Patras, Greece.tofidou).ment of Microbiology, School

tion for Professionals in Infection C

METHODS

Setting

This observational study was conducted in the ED of the Uni-versity General Hospital of Patras, a 700-bed tertiary care facility inPatras, Greece. The research protocol was approved by the hospi-tal’s Committee of Research, Ethics and Deontology and the Sci-entific Board.

Data collection

During a 5-month period, specimens were collected fromphysicians’ stethoscopes and from reusable medical devices(cardiac monitors, pulse oximeters, and electrocardiography ma-chines) in the ED. The ED operates 24 hours, 4 days a week. Theparticipating physicians completed an anonymous questionnaireeliciting demographic data and information on self-reportedcleaning habits.

All eligible physicians were invited to participate in the study.Physicians who did not carry their own stethoscope or had alreadyparticipated were excluded. Stethoscope diaphragms and surfacesof the reusable devices that come into contact with patients’ bodieswere swabbed with sterile cotton swabs moisturized with sterile

ontrol and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.

Table 1Demographic characteristics of the participating physicians (n ¼ 88)

Characteristic Number (%)

SexMale 50 (56.8)Female 38 (43.2)

Age group25-35 y 54 (61.4)>35 y 34 (38.6)

SpecializedYes 18 (20.5)No 70 (79.5)

SpecialtyInternal medicine 36 (40.9)General practice 27 (30.7)Cardiology 12 (13.6)Other 13 (14.8)

Working in the EDPermanently 11 (12.5)In shifts 19 (21.6)In shifts, changing with shifts at wards 58 (65.9)

Table 2Physicians’ self-reported stethoscope cleaning habits and level of hygiene training

Questionnaire Cleaning habits Number (%)

How often do you cleanyour stethoscope?

After every shift/patientexamination

31 (35.2)

After suspected contamination 26 (29.6)In certain cases/randomly/

when time allows it31 (35.2)

Means used for stethoscopecleaning?

Cleaning soap 5 (5.7)Alcohol 8 (9.1)Alcohol solution 75 (85.2)

Have you been educatedabout the need to cleanyour instruments?

Yes 10 (11.4)No 78 (88.6)

If yes, who provided thiseducation?

Your department 1 (10)Infection Control Committee 9 (90)

Have you been educatedabout the means ofcleaning yourinstruments?

Yes 4 (4.5)No 84 (95.5)

If yes, who provided thiseducation?

Your department 0 (0)Infection Control Committee 4 (100)

Table 3Bacterial contamination of stethoscopes and devices

Bacteria Contamination, n (%)* Isolates, n (%)

StethoscopesCFU>1000 28 (31.8)<1000 60 (68.2)

Bacterial speciesCoNS 85 (96.6) 151 (80.8)MRCoNS 18 19S aureus 6 (6.8) 6 (3.2)MRSA 2 2Other Gram-positive bacteriay 27 (30.7) 27 (14.4)A baumannii complex 3 (3.4) 3 (1.6)

Total 88 (100) 187 (100)DevicesCFU>1000 9 (75)<1000 2 (16.7)0 1 (8.3)

Bacterial speciesCoNS 9 (81.8) 16 (76.1)MRCoNS 1 1Other Gram-positive bacteriay 5 (45.5) 5 (23.9)

Total 12 (100) 21 (100)

*The majority of stethoscopes and devices were contaminated by multiple bacteria.yS viridans, Bacillus spp, Micrococcus spp, Corynebacterium spp.

E. Fafliora et al. / American Journal of Infection Control xxx (2014) 1-32

normal saline. The swabs were inoculated onto blood and Mac-Conkey agar plates and incubated at 37�C for a total of 48 hoursbefore being assessed as negative. Colony-forming units (CFUs)were measured, and phenotypically different colonies were sub-cultured and characterized by Gram stain. Gram-positive cocciwere classified as Staphylococcus aureus, coagulase-negativestaphylococci (CoNS), or Streptococcus viridans based on biochem-ical reactions. Gram-negative bacteria and Corynebacterium spp,Bacillus spp, and Micrococcus spp were identified using the Vitek 2system (bioMérieux, Marcy l’Etoile, France). Antimicrobial suscep-tibility was analyzed by the disk diffusion method.7 For cefoxitin-resistant staphylococci (ie, methicillin-resistant staphylococci[MRS]), methicillin resistance was verified by polymerase chainreaction for the mecA gene.8 Minimal inhibitory concentrations(MICs) of oxacillin, vancomycin, daptomycin, and linezolid in MRSwere determined by the E-test (bioMérieux).7

Statistical analysis

Descriptive statistics were estimated, and the Pearson c2 testwas used to control the statistical significance of proportions be-tween different groups. Moreover, the relationships betweenstethoscope cleaning habits and the demographic variables

(Table 1), as well as the relationships between the independentvariables plus stethoscope cleaning and handwashing habits andthe stethoscope bacterial loads, was assessed by multinomial lo-gistic regression. In the final step of the logistic regression, onlypossibly significant independent variables (P < .15, c2 test) wereincluded. Analyses were performed using SPSS version 17.0 (SPSS,Chicago, IL).

RESULTS

Twelve medical devices (6 cardiac monitors, 2 pulse oximeters,and 4 electrocardiography machines) and 88 physician stetho-scopes were sampled (n ¼ 100). The physicians’ demographiccharacteristics are summarized in Table 1. The vast majority prac-ticed handwashing (n¼ 84; 95.5%); however, only 57 (64.8%) did soafter each patient examination, and 20 (22.7%) did so only whenthey believed that their hands were dirty. The physicians’ self-reported cleaning habits and level of education on cleaning ofmedical tools are presented in Table 2. Compared with femalephysicians, male physicians were less likely to clean their stetho-scopes after each patient examination/after every shift than incertain cases/randomly/when time allows it (P ¼ .016; odds ratio[OR], 0.19; 95% confidence interval [CI], 0.05-0.62). All stethoscopes(100%) and 11 devices (91.7%) had at least 1 positive bacterial cul-ture (Table 3). Seventy-three of 88 stethoscopes (83%) and 6 of 11devices (55%) revealed multiple bacteria. Contamination wasgreater on stethoscopes of general practitioners compared withthose of other specialists (P ¼ .007; OR, 0.07; 95% CI, 0.01-0.51).Stethoscopes cleaned after each patient examination/every shifthad significantly lower bacterial loads (CFU <1000) compared withthose cleaned in certain cases/randomly/when time allows it (P ¼.001; OR, 0.09; 95% CI, 0.02-0.35). The percentage of high bacterialloads (CFU >1000) was 11% in groups of stethoscopes cleaned aftereach patient examination, 45% in those cleaned after every shift,69% in those cleaned after suspected contamination, and 100% inthose cleaned in certain cases/randomly/when time allows it (P <

.001). The stethoscopes that yielded methicillin-resistant S aureus(MRSA), Acinetobacter baumannii complex, and the majority ofmethicillin-resistant CoNS (MRCoNs; n ¼ 10; 55.6%) belonged tointernists.

E. Fafliora et al. / American Journal of Infection Control xxx (2014) 1-3 3

Among staphylococci (167 CoNS and 6 S aureus), 22 showedrelatively high resistance rates to kanamycin (77%), erythromycin(72%), and fusidic acid (64.1%). All MRS were susceptible to dapto-mycin (MIC, 0.032-0.25 mg/L), vancomycin (MIC, 0.5-2 mg/L), andlinezolid (MIC, 0.038-0.75 mg/L) except for 1 linezolid-resistantMRCoNS (MIC, >256 mg/L). Three of 12 S viridans and all A bau-mannii isolates were susceptible to the tested drugs.

DISCUSSION

This is the first study to evaluate physicians’ cleaning habits andbacterial loads of stethoscopes and other reusable medical devicesin a Greek ED. It is alarming that a considerable number of physi-cians reported not practicing handwashing after each patient ex-amination. Uneke et al6 reported significantly lower contaminationin stethoscopes belonging to health care workers who practicedhand hygiene. In contrast, in our study, the differences in hand-washing patterns were not correlated with the level of bacterialloads on physicians’ stethoscopes.

Furthermore, only 31 physicians (35.2%) cleaned their stetho-scope after each patient examination or every shift, in agreementwith results of previous studies.3,4 As expected, stethoscopescleaned frequently yielded statistically significantly lower bacterialloads (CFU <1000). Stethoscopes of general practitioners were lesscontaminated (30.7% with CFU <1000) than those of other spe-cialties, indicating that differences in roles or workloads maycontribute to the level of contamination and suggesting a possiblenew area for research. We emphasize that the frequency of hand-washing, sex, age, specialization status, and shifts worked were notassociated with bacterial loads.

Reported stethoscope contamination rates range widely, from30% to 97%.2-4,6 In the present study, all physician stethoscopes hada positive bacterial culture. CoNS, the predominant isolated mi-croorganisms reported in the literature,3-5 were isolated from 85 of88 stethoscopes.

Twenty MRCoNS isolates were detected on stethoscopes. To thebest of our knowledge, this is the first study to investigate theprevalence of MRCoNS on stethoscopes. The confirmed presence ofthe mecA gene, along with the antimicrobial resistance profiles ofmethicillin-resistant strains, have serious implications, given thatmultiresistant MRCoNS seem to be better adapted to hospital set-tings and can persist and spread within and among hospitals.9

Furthermore, the majority of the reusable medical devices in this

particular ED had a high bacterial load (CFU >1000), whereas 1electrocardiography machine yielded 1 MRCoNS isolate.

This study has several limitations. It was conducted in a singledepartment of a tertiary hospital and did not examine other routesof bacterial transmission. Moreover, all of the data regarding phy-sicians’ cleaning habits were self-reported.

To the best of our knowledge, this is the first study to evaluatebacterial contamination of a variety of devices used in the ED at thesame time. The majority of the examined equipment acted asbacterial reservoirs. The frequency of stethoscope cleaning was themain factor associated with bacterial load; thus, routine disinfec-tion of stethoscopes is recommended. Our results provide the firstdata in a Greek health care setting and thus can serve as a steppingstone for future studies to clarify the role of medical devices indisseminating infectious agents and to examine the effectiveness ofimplementing various hygiene strategies in decreasing the inci-dence of HAIs.

References

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9. Botelho AM, Nunes Z, Asensi MD, Gomes MZ, Fracalanzza SE, Figueiredo AM.Characterization of coagulase-negative staphylococci isolated from hospital in-door air and a comparative analysis between airborne and inpatient isolates ofStaphylococcus epidermidis. J Med Microbiol 2012;61:1136-45.