Hand hygiene has been considered to be the most important tool

Iraqi J Pharm Sci , Vol.18 (1) , 2009 Microorganisms from hospital soaps

Isolation of Some Microorganisms from Bar Soaps and Liquid Soaps
in Hospital Environments

Sarmad M.H. Zeiny
*,1

* Department of microbiology, college of medicine, University of Baghdad, Baghdad , Iraq

Abstract

This study was designed to determine the colonization of the in-use hand washing soaps in

hospital settings. It is a comparative cross-sectional research in a surgical specialties and Baghdad

teaching hospital in Baghdad, Iraq. Swabs from surfaces of bar soaps and from liquid soaps via their

applicator tips; at the sinks of toilets of hospital staff and working rooms of the wards were taken in

January 2008. Conventional microbiologic methods were used for culture of the swabs and

identification of the isolates. Colonization was detected 60% and 15.9% in bars and liquid forms

respectively. And this lead to the conclusion that bar soaps could be colonized with microorganisms

excessively. Liquid hand washing soaps are more appropriate in hospital environments. Proper using

conditions of the hand washing items should be defined in health care settings.

Keywords: Bar soap, liquid soap, pseudomonas aeruginosa, nosocomial infections.

الخالصة

حيت إنٗ انًزيض. حهٕد انيذ بانبكخزيا يؼخبز يٍ أْى انطزق الَخقال انؼذٖٔ بيٍ انًزضٗ أٔ يٍ انؼايهيٍ في يجال انزػايت انص

ْذفج ْذِ انذراست نخحذيذ بؼض اإلحياء انًجٓزيت انًسخؼًزة َظافت انيذ حؼخبز أْى أداة في انسيطزة ػهٗ حاالث انؼذٖٔ انًسخشفٕيّ.

صًًج ْذِ انذراست ػهٗ شكم يقارَت يقطؼيت ٔحى جًغ يسحاث يٍ أسطح انصابٌٕ ػهٗ إَٔاع انصابٌٕ انًسخخذو في انًسخشفياث.

أظٓزث هب ٔيٍ فخحاث جٓاس اإلػطاء نهصابٌٕ انسائم في يسخشفٗ بغذاد انخؼهيًي ٔ انجزاحاث انخخصصيت في بغذاد, انؼزاق.انص

% نهصابٌٕ انسائم. ْذِ انُخائج حؤكذ أٌ اسخؼًال انصابٌٕ 1..9% بيًُا كاَج 06انُخائج أٌ َسبت حهٕد انصابٌٕ انصهب كاَج

بٌٕ انصهب.انسائم بانًسخشفياث اَسب يٍ انصا

Introduction

Hand carriage of bacteria is an important

route of transmission of infection between

patients or from the health care worker to the

patient.
1-6

Hand hygiene has been considered

to be the most important tool in nosocomial

infections control. Failure to perform

appropriate hand hygiene is supposed to be the

leading cause of nosocomial infections and the

spread of multiresistant microorganisms, and

has been recognized as a significant

contributor to outbreaks. The microbial flora

of the skin of hands consists of resident and

transient microorganisms. The resident

microorganisms survive and multiply on the

skin. The transient microorganisms represent

recent contaminants of the hands acquired

from colonized or infected patients/clients or

contaminated environment or equipment.

Transient microorganisms are not consistently

isolated from most persons. In contrast to the

resident microorganisms, the transient

microorganisms found on the hands of health

care personnel are more frequently implicated

as the source of nosocomial infections. The

most common transient microorganisms

include gram negative coliforms and

Staphylococcus aureus. Hand washing with

plain soap is effective in removing most

transient microrganisms.
7-9

The mechanical

action of washing and rinsing removes most of

the transient microorganism present.
10-

12
.Health care workers wash their hands in two

ways: (a) the social hand wash, which is the

cleaning of hands with plain, non-medicated

bar or liquid soap and water for removal of

dirt, soil, and various organic substances; (b)

the hygienic or antiseptic hand wash, which is

the cleaning of hands with antimicrobial or

medicated soap and water. Most antimicrobial

soaps contain a single active agent and are

usually available as liquid preparations.

Appropriate hand washing results in a reduced

incidence of both nosocomial and community

infections.
13

Much studies have been written

and debated regarding the use of bar versus

liquid skin cleansers in relation to infection

control.
7,14-22

In this study, the aim was to

detect and compare bacterial contamination of

soap bars and liquid soaps.

1 Corresponding author E-mail : smzeiny2002@yahoo.com

Received : 9/11/2008

Accepted : 22 / 2/2009

Iraqi J Pharm Sci , Vol.18 (1) , 2009 Microorganisms from hospital soaps

Materials and Methods

Setting

Surgical specialties and Baghdad

teaching hospital in Baghdad, at the middle of

Iraq.

Materials

In January 2008, 50 swabs from surfaces

of bar soaps at the sinks of toilets and working

rooms of the wards were collected; 44 swabs

were collected from tips of the applicators of

liquid soaps containers approximately at the

same hospital points. Swabs were collected

from wet surfaces of bars and tip of the

containers of liquid soaps. Soap bars were

plain soaps (Duru, Turkey). Liquid soaps

(Johnson, Turkey) included formaldehyde (in

trace amount as antiseptic agent according to

label information). Despite of the liquid soaps

in this settings were called antibacterial by the

manufacturer; formaldehyde that was included

in the liquid soaps considered as preservative

rather than antibacterial effect.

Microbiology

Collected swabs were dipped into tubes

containing 1 ml sterile normal saline (0.9%).

Samples were brought to the microbiology

laboratory without delay. Tubes were shaked

and Ten microliter of substance was inoculated

on blood agar and eosin-methylen-blue (EMB)

agar incubated at 37
0
C for 22-24h.

Sabouraud`s agar media are enforced with

chloramphenicol (16 µg/mL) to inhibit the

growth of contaminating bacteria; incubated at

30C˚, for 30 days were used to rule out fungi .

Unfortunately anaerobic laboratory conditions

could not be accomplished during this study

due to the shortage in laboratory facilities.

Yielded microorganisms were identified by

conventional microbiological methods and by

using API 20E, API 20NE & API Strep

(Biomerieux, USA).

Statistics

T-tests were used for calculating
significance of difference of colonization rates

between bar soaps and liquid soaps and also

comparing the frequency of yielding

microorganisms.

Results

Among 50 swabs of bar soaps, 30 (60%)

swabs were found colonized. A total of 44

microorganisms were isolated. Numbers of

isolate are shown in figure 1. Pseudomonas

aeruginosa (41%) was the most frequent

isolated bacteria followed by Escherichia coli

(13.6%) and Acinetobacter baumanii

(11.4%).From liquid soaps, 6 microorganisms

were detected at only 7 tips (15.9%) of the

total 44 containers. This includes 4 (66.6%) P.

aeruginosa, one (16.6%) Proteus penneri and

one (16.6%) Flavimonas oryzihabitans.

Comparison of the rates of bacterial

colonization between bar soaps and liquid

soaps are shown in figure 2 and 3.Bar soaps

were found more colonized than the liquid

soaps significantly (p<0.05). P. aeruginosa

was the most frequent isolate in both two

group whereas isolation rate was significantly

higher (p<0.05) in bar soaps but not in the

liquid soaps (p>0.05) as statistically.

Iraqi J Pharm Sci , Vol.18 (1) , 2009 Microorganisms from hospital soaps

Figure 1. Distribution of bacterial agents colonizing on the soaps

Figure 2. Bacterial colonization rates of

bar soaps

Figure 3. Bacterial colonization rates of

liquid soaps

4
18

1
1

0 2 4 6 8 10 12 14 16 18

NUMBERS

P.aeruginosa

E.coli

A.baumanii

E.aerogenes

E.cloaca

S.aureus

P.penneri

C.idolegenens

F.brevis

Candida

Diphtheroid

F.oryzihabitans
A

G
E

N
T

DISTRUTION OF BACTERIAL AGENTS COLONIZING ON THE SOAPS

BAR SOAP

LIGUID SOAP

Bacterila grow th,

60%

No grow th, 40%

Bacterila growth

No growth

Bacterila grow th,

16%

No grow th, 84%

Bacterila growth

No growth

Iraqi J Pharm Sci , Vol.18 (1) , 2009 Microorganisms from hospital soaps

Discussion

The most common hand-cleaning agents
are bar soap and liquid soap in disposable

plastic containers. When in use, bar soaps are

frequently misused because they are typically

stored in contact with moisture and remain

moist for long periods of time. It is usually

kept in a container, on or next to a wash basin.

More often than not, it resides in surface water.

The resulting jelly mass is unsightly, difficult

to use effectively. This supplies an

environment which provides the perfect

opportunity for bacteria and organisms to

grow. Most bars of soap in communal areas

are used by a number of different people. This

means that one bar of soap can be in direct

contact with skin bacteria from more than one

person, and may harbour live pathogenic

bacteria.
22

Cross infection can and does occur

under these circumstances.
23

When using a bar

of soap, the CDC (Centre for Disease Control)

recommends placement on a drainable rack

between uses.
6
Soap racks that promote

drainage of all water from the bar should be

installed. In addition, there should be easy

access to replacements when soap is lost,

dropped, melted, or consumed. Small soap

bars were also recommended that can be

changed and used in preference to larger bars

that are more likely to melt or become

colonized with bacteria.
24

Liquid soap on the

other hand is much better to use. Liquid soap is

dispensed straight from a plastic container. It

has not been exposed to skin bacteria or other

contaminants. As a result, cross contamination

is not likely to occur, providing a more

cleaning and more hygienic

alternative.
23

McBride et al reported that bar

soaps were found to have higher bacterial

cultures after use than liquid soaps.
23

another study, Kabara and Brady obtained

samples from bar and liquid soaps from 26

public bathrooms which were investigated.

Liquid soaps were found to be negative for

bacteria, while 100% of the 84 samples

obtained from bar soaps yielded positive

cultures.
15

In an epidemiological study, the

researchers isolated several strains of

Pseudomonas from 45 of 353 environmental

samples used by multiple providers (13%) and

found that the 5 most common strains were

frequently found on patients. They also

affirmed that the hands are a major vehicle for

the transfer of Pseudomonas bacteria and

implicated bar soap in its spread.
14

Other

groups of researchers have found that bacteria

survive on soap bars in continuous use in

public lavatories, even when cultured 48 hours

following their last use.
15,22 The role of the

soap dish in infection control has also been

studied. Despite of CDC recommendations

most health care settings like our hospital are

using soap dishes instead of drainable racks.

Jarvis et al showed that supplies used for hand

washing can be contaminated with gram-

negative organisms if they are not completely

dried. Swabs were collected from soap dishes

on 6 wards and from a bacteriology laboratory

on 4 consecutive days. The sludge of the dish

was found to be colonized with predominantly

gram-negative bacteria. This colonization

persisted, even when medicated iodophor bar

soap was used.
25

In our study, dishes were

found wet, and surfaces of soaps were

generally covered by squashy mass and bars

were found heavily contaminated (%88). This

study revealed quite lower contamination rate

in liquid soaps compared with bar soaps,

although they didn’t include suggested

antibacterial agents for hand antisepsis such as

triclorasan or chlorhexidine. However, liquid

soaps would be expected to be sterile. So, there

should be problems with the handling.

Honestly, in this study any strict procedures

had not been followed in the wards for the how

often liquid dispensers should be cleaned,

disinfected or exchanged. After the results

were obtained, procedures were described for

handling and usage of liquid soaps and

dispensers immediately. In conclusion, correct

use of hand washing materials is more

important choosing kind of soaps. Hypothesis

of transferring microorganisms to healthcare

workers’ hands via contaminated soap bars

have not confirmed, antibacterial or not, liquid

soaps seem more suitable alternative for

hygienic hand washing. Proper handling of

liquid soap should be implemented wherever

they are used in the hospital. Compliance of

the hand washing is more important than the

kind of the soap.

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