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 Table of Contents  
ORIGINAL ARTICLE
Year : 2020  |  Volume : 4  |  Issue : 2  |  Page : 100-105

Detection of the frequency of microbial defilement “in-use” soap products at various dental departments: A microbiological research


1 Department of Public Health, UWA School of Population and Global Health, University of Western Australia, Perth, Australia
2 Department of Oral Medicine and Radiology, Rama Dental College, Kanpur, Uttar Pradesh, India

Date of Submission18-Sep-2020
Date of Acceptance04-Nov-2020
Date of Web Publication28-Jan-2021

Correspondence Address:
Dr. Rohan Sachdev
117/K-68, Sarvodaya Nagar, Kanpur, Uttar Pradesh
Australia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/sidj.sidj_40_20

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  Abstract 

Context: Hand washing by a dental health professional before having contact with a patient's oral cavity is considered a fundamental dental clinic infection control measure.
Aims: The aim of this study was to evaluate bar soap and liquid soap from dental departments for microbial contamination while it was in use.
Settings and Design: This exploratory, cross-sectional study was carried out to identify microorganisms' presence in handwashing with liquid and bar soap at clinical and nonclinical departments in a dental college.
Subjects and Methods: In the 2-month study period, all the dental students, dental faculty, and the other auxiliaries present were the participants, and a total of 35 handwashing place samples from 15 different dental departments were collected. The test tube samples of bar soap and liquid soap were all transferred to the microbiology laboratory for microbiological analysis of the samples.
Statistical Analysis Used: Data were analyzed using a one-sample paired t-test and independent Student's t-test.
Results: Nine different microbial species were identified. In both soaps, the abundance of Staphylococcus aureus was higher as compared to that of other microorganisms. Further, in both soaps, the mean number of microorganisms increased statistically significantly (P < 0.05 or P < 0.01 or P < 0.001) at post-use as compared to at pre-use except Aspergillus niger in liquid soap. However, the post-use mean abundance of microorganisms was found similar (P > 0.05) between the two groups (soaps).
Conclusions: The microbial load of the in-use bar soap and liquid soap constituted a mixed flora of Gram-positive bacteria, Gram-negative bacteria, aerobes, anaerobes, and fungi. The results indicate that the bar soap under “in-use” condition harbors more of microorganisms as compared to that of liquid soap, and handwashing with such a soap may lead to the spread of infection.

Keywords: Bar soap, dentist, handwashing, liquid soap, microbial load, soap contamination


How to cite this article:
Sachdev R, Garg K, Saxena S, Shwetam S, Mehrotra V, Srivastava A. Detection of the frequency of microbial defilement “in-use” soap products at various dental departments: A microbiological research. Saint Int Dent J 2020;4:100-5

How to cite this URL:
Sachdev R, Garg K, Saxena S, Shwetam S, Mehrotra V, Srivastava A. Detection of the frequency of microbial defilement “in-use” soap products at various dental departments: A microbiological research. Saint Int Dent J [serial online] 2020 [cited 2021 Jun 14];4:100-5. Available from: https://www.sidj.org/text.asp?2020/4/2/100/308178


  Introduction Top


Dentists' hands have been recognized as the major reservoirs of pathogens that may cause clinical infections while treating the oral cavity.[1] Hand hygiene in dental practice is one of the most important parts of the infection control process to reduce the risk of transmitting microorganisms from dentist to patient.[2],[3]

In 1988 and 1995, guidelines for handwashing were published by the Association of Professionals in Infection Control and indications were recommended for handwashing, which were similar to those presented in the Centers for Disease Control and Prevention guidelines.[4],[5] There are microorganisms everywhere, such as in dirt, water, waste, stagnant water, and also in human bodies, and these assaults on human bodies are of particular significance in terms of oral health.[6],[7] The transient microorganisms found on the dentist's hands are more frequently implicated as the source of infections and may be of various types that include  Escherichia More Details coli,  Salmonella More Details spp., and hepatitis A virus. The most common transient microorganisms include Gram-negative coliforms and Staphylococcus aureus.[7],[8]

Dentists always operate in the oral cavity, so it is essential to wash hands with clean medicinal or antimicrobial soap and clean water to avoid infection from occurring.[9],[10] It has been observed that bar and liquid soaps are routinely used for handwashing by dentists in their clinics.[11],[12] Past studies stated the presence of various microorganisms more on bar soap as compared to the “in-use” liquid soaps.[13],[14] The purpose of this study was to investigate whether bar soap or liquid soap is highly susceptible to contamination and transmission of infection or not with microorganisms in the cleaning of hands by the dentists.


  Subjects and Methods Top


A cross-sectional exploratory study was carried out on dentists working in various departments on this dental institute to identify the frequency of microorganisms in bar and liquid soap- washed hand samples. During the 2 month period from January to February 2020, after Institutional ethical committee clearances, 35 specimens of the bar and liquid soap washed hand samples were collected from nine clinical, two preclinical, and four basic science dental departments, including dental emergency and dental oncology were sent for microbiological evaluation. All dental students, dental faculty, and other assistants present were participants of this study. None of them were aware of the purpose of the study. We did this to eliminate any bias that could affect the results.

Sample selection

To begin with, in the 1st month of study, fresh bar soap (one of the medicated soaps) commonly used by the dental college, collected from the central storeroom of the college, was placed at the dental department's handwashing sites. The soap sample was taken at pre-use (pre or 0 week) and post-use consecutively for 4 weeks (1 week, 2 weeks, 3 weeks, and 4 weeks). The bar soap was weighed before and after 7 days to maintain uniformity and to measure the soap use, respectively. The bar soap samples were obtained by using sterile cotton swabs moistened with phosphate-buffered solution (PBS). Under sterile conditions, the moistened cotton swab was slid in a single stroke over the top portion of the bar soap, which was placed in the soap dish at the washing site in the department. The hand washed sample was immediately collected into a sterile test tube containing 2 mL of PBS (phosphate buffered saline and it was ensured with utmost caution that at any time the fingers of the tester would not come in contact with the hand washed sample collected in the tube.

In the second month of the study, We removed the bar soap previously used in handwashing, replaced it with a button to supply liquid soap filled in a rectangular-shaped plastic dispenser, and placed it at all dental departments' handwashing sites. Each time 12 ml samples of hands washed using liquid soap were collected twice a week for 4 weeks during and at the end of use and these collected samples in an aseptic condition were sent to the microbiological lab for examination.

Microbiological study

The test tubes were vigorously shaken for 30 s, and for culturing of microorganisms, direct streaking of the collected hand wash swab was the method of choice for bar soap samples. For liquid soap samples, concentrate possible microorganisms, centrifugation, and filtration in membranes made of material resistant to the products were used, with 0.22 pores, according to protocols established by the microbiology laboratory.[14] One cotton swab streak as well as liquid soap hand washed sample analysis was made by using two agar plates; chocolate agar for Gram-positive aerobes and facultative, MacConkey agar for Gram-negative aerobes and facultative, and blood agar for anaerobes. These plates were incubated for 48 h at 37°C aerobically and anaerobically. Sabouraud's dextrose agar was used for fungi. It was incubated for 5 days at 37°C. After incubation, the isolated microorganisms were identified through biochemical tests in a semi-automated culture and identification system. The plates were counted for microbial colonies and expressed as colony-forming units (CFU)/per bar and CFU/mL of liquid soap.

Statistical analysis

Statistical Package for the Social Sciences (SPSS Inc., Released 2008, SPSS Statistics for Windows, version 19.0. Chicago, IL, USA) was used for statistical analysis. The frequency of microorganisms (number) was summarized as mean ± standard deviation (SD). The microorganism's frequency in pre- and post-hand washed sample were compared by one sample paired t-test considering SD of pre as post SD. Independent Student's t-test compared the post microorganism's frequency of hand-washed samples of two groups (soaps and liquid soap). A two-tailed (α) P < 0.05 was considered statistically significant.


  Results Top


Bar soap

The pre (week 0) and post (weeks 1, 2, 3, and 4) bar soap use frequency (number) of different microorganisms is summarized in [Table 1] and also depicted in [Figure 1]. At pre-use (i.e., fresh unused bar soap), 35 samples were found to be free of microorganisms, that is, 0, while after use, all showed an abundance of microorganisms with the highest mean of S. aureus and least of Aspergillus niger.Statistically comparing the pre and post mean abundance of microorganisms, a one-sample paired t-test showed statistically significant (P < 0.05 or P < 0.01 or P < 0.001) abundance of all the microorganisms at post-use as compared to pre-use.
Table 1: Pre- and post-bar soap use frequency (mean±standard deviation, n=4) of the presence of microorganisms

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Figure 1: Post bar soap use frequency of the presence of microorganisms

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Liquid soap

The pre (week 0) and post (weeks 1, 2, 3, and 4) liquid soap use frequency (number) of different microorganisms is summarized in [Table 2] and also shown in [Figure 2]. At pre-use (i.e., fresh unused liquid soap), like bar soap, liquid soap also showed all the 35 samples free of microorganisms, that is, 0, while after use, all showed an abundance of microorganisms with the highest mean of S. aureus and least of diphtheroids. Statistically comparing the pre and post mean abundance of microorganisms, a one-sample paired t-test showed statistically significant (P < 0.05 or P < 0.01 or P < 0.001) abundance of all microorganisms at post-use as compared to pre-use, except A. niger.
Table 2: Pre- and post-liquid soap use frequency (mean±standard deviation, n=4) of the presence of microorganisms

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Figure 2: Post liquid soap use frequency of microorganisms

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Bar soap versus liquid soap

The frequency of microorganisms after bar soap and liquid soap use are summarized in [Table 3] and shown in [Figure 3]. The mean number of microorganisms of Candida parapsilosis, Klebsiella sp., and S. aureus was higher in bar soap as compared to that of liquid soap. However, the mean number of microorganisms of aerobic spore bearers, such as A. niger, E. Coli, Staphylococcus citreus, and Staphylococcus epidermidis, was higher in liquid soap as compared to that of bar soap. However, the mean number of microorganisms of C. parapsilosis, Klebsiella sp., and S. aureus was higher in bar soap as compared to that of liquid soap. However, the mean number of microorganisms of diphtheroids was found similar between the two groups. Comparing the mean frequency of microorganisms of the two groups, Student's t-test showed similar (P > 0.05) results between the two groups (soaps), that is, did not differ significantly.
Table 3: Post bar soap and liquid soap use frequency (mean±standard deviation, n=4) of the presence of microorganisms

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Figure 3: Post bar soap and liquid soap use frequency of microorganisms

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In the present study, the microbial load of the “in-use” bar soap and liquid soap constituted a mixed variety of Gram-positive bacteria, Gram-negative bacteria, aerobes, anaerobes, and fungi, in total microbial population obtained from hand washed sample with bar and liquid soap represented eight different varieties [Table 4] and also shows the comparison of the microbial isolates with the present study from three other published previous studies.[7],[9],[14]
Table 4: Summary of different isolates found in “in-use” bar soaps and liquid soap dispensers

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  Discussion Top


Hand washing is a prime practice used to reduce the possibility of contamination and propagate it. Most general dental practitioners also use soap and water for handwashing.[1] Acceptable products for hand hygiene in various clinical and non-clinical dental departments include plain bar soap, liquid soap, antimicrobial soap, alcohol hand rubs, and appropriate lotions.[15],[16]

In the present study, after microbiological examination shows the presence of frequency of the diverse microorganisms [Table 1] during pre and post-use of bar soap were S. aureus, Klebsiella species, E. coli, and S. citreus with few others listed in [Table 1].

In our study, a self-designed protocol was used to investigate the microbial contamination of bar soap and liquid soap under in-use conditions in various dental clinical and non-clinical departments. This analysis shows that all (100%) bar soaps and liquid soap dispensers in usage conditions yielded positive culture. This result is in accordance with that of other similar studies performed in 1984 and 1993.[11],[13] As shown in [Table 2], after the pre and post-use of liquid show the frequency of diverse microorganisms listed are S. aureus, E. Coli, Klebsiella species and S. citreus. In a study done by Kabara and Brady in 1984, on bar and liquid soaps collected from 26 public lavatories were investigated for microbial colonies and found 100% positive culture report after analyzing 84 samples obtained from bar and liquid soap and the microbial population obtained from the bar and liquid soap represented over 16 different genera.[11] Similar results were observed in the current study where all the samples showed positive results for the presence of microorganisms.

In a study conducted by McBride in 1984, 92%–96% of the samples from the “in-use” bar soaps (with and without antibacterial) yielded positive culture.[12] Similar results were found in a study done by Hegde et al. in 2006, which is in accordance with the current study.[9] In a study conducted in a household setting, Brook and Brook studied the microbial content of 14 bar soap. The significant bacteria isolated were Staphylococcus and Enterobacteriaceae. It was also observed that the number of bacteria isolated from heavily used soaps that were wet was higher than that from infrequently used soaps that were dry.[13]

The significance of handwashing is more vital when it is allied to dentists because of possible contagious influence of bacteria that can be pathogenic, and studies have revealed that liquid soaps contain active antimicrobial ingredients which take away more bacteria as compared to plain soap.[17] Sajed et al. in 2014 analyzed samples obtained from day-to-day in-use dispensers and stated that liquid soaps are more effective in eradicating S. aureus and E. coli species.[18] These results illustrate that liquid soaps significantly decrease the bacterial population than bar soaps. Similar results have been deduced by Caetano et al. in 2011 and by Toshima in 2001, which is in accordance to the liquid soap sample results of the present study.[14],[19]

In the present study, the significant bacteria isolated were Staphylococcus and Enterobacteriaceae. It was also observed that the number of bacteria isolated from heavily used bar soaps that were wet was higher than that isolated from infrequently used bar soaps that were dry.

In this study, the presence of diverse microorganisms found in in-use bar soap and liquid soap samples suggests that bar soap and dispenser handles may be an important infection reservoir. S. aureus, E. Coli, and Klebsiella which are isolates from the samples are shown to be the prime organisms that cause nosocomial infections.[7] The use of such a contaminated product may thus serve as a continuous source of infection and re-infection for the users.[9],[13] The present study results may have implications for health professionals and medical educators aiming to design effective programs to promote hand hygiene practices. Future research needs to research the impact of different hand hygiene procedures to remove bacteria present in dentists' hands.


  Conclusions Top


Dentists' hands are open to many substances that aid in transmitting and spreading pathogens that can cause diseases such as food-borne and nosocomial infections. Hand washing is the single most effective intervention to reduce the incidence of related diseases in the health-care sector. Unfortunately, compliance with standard hand hygiene protocols has generally been poor in the health-care environment. While antibacterial liquid soaps have experimentally proven to destroy the bacteria at a certain concentration. Dentists should use soaps in their clinical and nonclinical workplaces according to the health and hygiene criteria. In this way, many patients with immunocompromised status or poor tolerance will be covered against the transmission of pathogenic or opportunistic pathogens. Dental care staff should be encouraged to use liquid soap instead of bar soap in hand washing to protect from contamination and they should also increase awareness of the use of liquid soap to protect patients from the occurrence of bacterial contamination.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Myers R, Larson E, Cheng B, Schwartz A, Da Silva K, Kunzel C. Hand hygiene among general practice dentists: A survey of knowledge, attitudes and practices. J Am Dent Assoc 2008;139:948-57.  Back to cited text no. 1
    
2.
Naik S, Khanagar S, Kumar A, Vadavadagi S, Neelakantappa HM, Ramachandra S. Knowledge, attitude, and practice of hand hygiene among dentists practicing in Bangalore city-A cross-sectional survey. J Int Soc Prev Community Dent 2014;4:159-63.  Back to cited text no. 2
    
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World Health Organization. WHO Guidelines on Hand Hygiene in Health Care: A Summary. Geneva: World Health Organization; 2009. p. 1-5.  Back to cited text no. 3
    
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Larson E. Status of practice guidelines in the United States: CDC guidelines as an example. Prev Med 2003;36:519-24.  Back to cited text no. 4
    
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Boyce JM, Pittet D, Healthcare Infection Control Practices Advisory Committee, HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. Guideline for hand hygiene in health-care settings. Recommendations of the healthcare infection control practices advisory committee and the HICPAC/SHEA/APIC/IDSA hand hygiene task force. Society for healthcare epidemiology of America/Association for Professionals in infection control/infectious diseases society of America. MMWR Recomm Rep 2002;51:1-45.  Back to cited text no. 5
    
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Johnson SA, Goddard PA, Iliffe C, Timmins B, Rickard AH, Robson G, et al. Comparative susceptibility of resident and transient hand bacteria to para-chloro-meta-xylenol and triclosan. J Appl Microbiol 2002;93:336-44.  Back to cited text no. 6
    
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Srinivasan K, Chitra S. Consumer antibacterial soaps: Effective or just risky? Examination of the evidence. Saudi J Med Pharm Sci 2016;2:12-18.  Back to cited text no. 7
    
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Larson EL. APIC guideline for handwashing and hand antisepsis in health care settings. Am J Infect Control 1995;23:251-69.  Back to cited text no. 8
    
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Hegde PP, Andrade AT, Bhat K. Microbial contamination of “in use” bar soap in dental clinics. Indian J Dent Res 2006;17:70-3.  Back to cited text no. 9
[PUBMED]  [Full text]  
10.
Kampf G, Kramer A. Epidemiologic background of hand hygiene and evaluation of the most important agents for scrubs and rubs. Clin Microbiol Rev 2004;17:863-93.  Back to cited text no. 10
    
11.
Kabara JJ, Brady MB. Contamination of bar soaps under “in-use” conditions. J Environ Pathol Toxicol Oncol 1984;5:1-4.  Back to cited text no. 11
    
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McBride ME. Microbial flora of in-use soap products. Appl Environ Microbiol 1984;48:338-41.  Back to cited text no. 12
    
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Brook SJ, Brook I. Contamination of bar soaps in a household setting. Microbios 1993;76:55-7.  Back to cited text no. 13
    
14.
Caetano JA, Lima MA, Di Ciero Miranda M, Serufo JC, Ponte PR. Identification of bacterial contamination in liquid soap for hospital use. Rev Esc Enferm USP 2011;45:153-60.  Back to cited text no. 14
    
15.
Andrews N, Cuny E, Molinari JA. Antisepsis and hand hygiene. In: Molinari JA, Harte JA, editors. Cottone's Practical Infection Control in Dentistry. 3rd ed. Philadelphia, PA: Lippincott, Williams and Wilkins; 2010. p. 125.  Back to cited text no. 15
    
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Fluent MT. Hand hygiene in the dental setting: Reducing the risk of infection. Compend Contin Educ Dent 2013;34:624-7.  Back to cited text no. 16
    
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Rama WA. APIC guideline for selection and use of disinfectants in hand hygiene. Amer J Infect Control 2001;24:313-342.  Back to cited text no. 17
    
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SajedAN, Shagufta, Haider S, Nosheen, Yousaf W, Ahmed I, et al. Antibacterial activity of liquid hand washes against daily encounter bacteria. IOSRPHR 2014;4:19-23.  Back to cited text no. 18
    
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Shahida H. Antibacterial activity of soap against daily encountered bacteria. Afr J Biotechnol 2009;8:1431-36.  Back to cited text no. 19
    


    Figures

  [Figure 1], [Figure 2], [Figure 3]
 
 
    Tables

  [Table 1], [Table 2], [Table 3], [Table 4]



 

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