Anti-bacterial efficacy of alcoholic hand rubs in the Kenyan market, 2015
Ochwoto et al. Antimicrobial Resistance and Infection Control
Anti-bacterial efficacy of alcoholic hand rubs in the Kenyan market, 2015
Missiani Ochwoto 0
Lucy Muita 0
Keith Talaam 0
Cecilia Wanjala 0
Frank Ogeto 0
Faith Wachira 0
Saida Osman 0
James Kimotho 0
Linus Ndegwa 1
0 Production Department, Kenya Medical Research Institute , P. O. Box 54840-00200, Nairobi , Kenya
1 Centers for Disease Control and Prevention , Nairobi , Kenya
Background: Hand hygiene is known to be effective in preventing hospital and community-acquired infections. The increasing number of hand sanitizer brands in Kenyan hospitals and consumer outlets is of concern. Thus the main aim of this study was to evaluate the anti-bacterial efficacy and organoleptic properties of these hand sanitizers in Kenya. Methods: This was an experimental, laboratory-based study of 14 different brands of hand sanitizers (coded HS1-14) available in various retail outlets and hospitals in Kenya. Efficacy was evaluated using standard non-pathogenic Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC 25923) and Pseudomonas aeruginosa (ATCC 27853) as per the European Standard (EN). The logarithmic reduction factors (RF) were assessed at baseline and after treatment, and log reduction then calculated. Ten and 25 healthy volunteers participated in the efficacy and organoleptic studies respectively. Results: Four (28.6%) hand sanitizers (HS12, HS9, HS13 and HS14) showed a 5.9 reduction factor on all the three bacteria strains. Seven (50%) hand sanitizers had efficacies of <3 against all the three bacteria strains used. Efficacy on E. Coli was higher compared to the other pathogens. Three hand sanitizers were efficacious on one of the pathogens and not the other. In terms of organoleptic properties, gel-based formulations were rated far higher than the liquid based formulations brands. Conclusion: Fifty percent (50%) of the selected hand sanitizers in the Kenyan market have efficacy that falls below the World Health Organization (WHO) and DIN EN 1500:2013. Of the 14 hand sanitizers found in the Kenyan market, only four showed efficacies that were comparable to the WHO-formulation. There is a need to evaluate how many of these products with <3 efficacy that have been incorporated into the health system for hand hygiene and the country's policy on regulations on their usage.
Hand rubs; Hand sanitizer; Efficacy; Organoleptic; Reduction factor
Globally, the prevalence of hospital associated infections
(HAIs) ranges from 4 to 10% in developed countries, and
has been reported as being more than 20% in developing
countries . Studies by Ndegwa et al.  established an
overall incidence of respiratory HAIs in three major
hospitals in Kenya to be 9.2 per 10,000 patient days, with the
highest incidence being in the Intensive Care Units (ICUs).
Hand hygiene is known to be effective in preventing
hospital and community-associated infections, and a number
of studies have demonstrated the benefits of hand sanitizers
in both community and hospital settings [5, 10, 15, 16].
Alcohol-Based Hand Rubs (ABHRs) are the most widely
used hand sanitizers . They may contain additional
active ingredients such as quaternary ammonium compounds
(QAC), povidone-iodine, triclosan or chlorhexidine that
mainly serve to contribute to the efficacy of formulations
[1, 8, 14]. Alcohols act by denaturing proteins, and are most
effective at concentrations of 60–80%. Concentrations
higher than 80% alcohol are less potent because proteins
are not easily denatured in the absence of water .
Alcohols manifest a good in vitro germicidal activity against
Gram-positive and Gram-negative vegetative bacteria as
well as various strains of fungi. However, they have minimal
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activity against bacterial spores, protozoan oocytes and
some non-enveloped (non-lipophilic) viruses . The
reference standard against which ABHRs are compared is
60% isopropanol . In most cases, the efficacy of ethanol
and isopropanol are comparable, though ethanol has been
found to have better efficacy profile against viruses .
Some studies have demonstrated that ethanol gel
formulations, unless they have been specially formulated and
tested, are less efficacious than ethanol solution
formulations [2, 7]. There are a number of hand sanitizers sold to
the Kenyan market with labels on their package that claim
that the handrub can kill 99.9% of germs. The objective of
this study was to evaluate the anti-bacterial efficacy and
organoleptic properties of the hand sanitizers available in
the Kenyan market, to help set the standards required for
hand sanitizers in the country.
Fourteen (14) available brands of hand sanitizers (Fig. 1) were
picked from various retail outlets and hospitals in Kenya. The
total number of hand sanitizers, in the market was not
available at the time of the study, therefore, the investigators
regularly picked up to four different batches of the each hand
sanitizer that was in the market from September 2014 to July
2015. Thirty-five healthy volunteers participated in the study:
10 for efficacy and 25 for organoleptic studies.
The number of viable bacterial microbes present after
application of the hand rub was used to calculate the efficacy
of the hand rub. A hand rub with the ability to reduce the
microbes by 50% (equivalent to Log reduction below 3)
was considered efficacious. Efficacy testing was carried out
step by step as described in the European Standard (EN)
1500:2013; briefly, the standard non-pathogenic
Escherichia coli (ATCC 25922), Staphylococcus aureus (ATCC
25923), and Pseudomonas aeruginosa (ATCC 27853) were
incubated overnight in a sterile broth suspension.
Ten staff members of KEMRI volunteered to participate
in the study and verbal informed consent was sought. The
hand rub/sanitizer (HS) samples were fully concealed to
the participants; the containers of HS were wrapped with
identical opaque papers leaving only the cap of the HS
open with codes labelled HS1-14.
All the participants were expected to test all the different
batches of HS for all the three pathogens. The initial
procedure required the participants to thoroughly wash their
hands with soap and water and drying them with paper
towels. This was followed by contaminating of 4 fingers in
a 10 ml 0.5 Mac Farland suspensions of bacteria (A)
prepared as per the method described by the National
Committee for Clinical Laboratory Standards . A
second set of sterile broth (B) was used to determine the
post-value Colony Forming Units (CFU) after sanitizing
with respective hand sanitizer. All the hand washing and
sanitation were done as described in WHO Hand Hygiene:
Why, How & When - brochure of 2009 . Ten microliter
(10 μl) of each of suspension was inoculated on Tryptic Soy
Agar (TSA) and incubated at 37 °C overnight for pre-value
and post-value colony-forming unit (CFU) count
respectively. Logarithmic reduction factors (RF) were assessed
based on the baseline and after treatment with the HS and
the results of each HS were compared with the reference
standard (60% IPA). The logarithmic reduction factor was
then expressed as a percent reduction. Log reduction was
calculated as log10 (A) - log10 (B) and the percent reduction
was calculated as (A-B)/A% where; where A = number of
Fig. 1 A photograph of hand sanitizers in the Kenyan market that were used in the study
viable microorganism at baseline and B = number of viable
microorganism after treatment [4, 18].
A questionnaire was designed to test organoleptic
properties of the hand sanitizers in the Kenyan market. The
organoleptic properties tested using the questionnaires were:
general appearance and feeling of the hand after use and
ease-of-use. The 25 selected participants were requested to
score the hand sanitizers: 5 as “excellent”, 4 as “good”, 3 as
“fair”, 2 as “poor” and 1 as “very poor” and a mean product
rating was calculated. During the testing process, the
identity of the hand sanitizers was concealed to the participants,
by wrapping the containers with opaque papers, leaving
only the cap of HS open. This made it difficult for the
participants to recognize or speculate the product.
All hand sanitizer products sampled listed ethanol or
isopropyl alcohol as its active ingredient either in single form
or in combination with other compounds. We did not do
any chemical analysis of the hand sanitizers. Those hand
sanitizers that were in single form had different ethanol
concentration (70–75%) and they include HS2, HS3, HS4,
HS5, HS6, HS7, and HS13 (Table 1). Among ethanol-based
hand sanitizers that were in combination with other
compounds, there were four different compounds used
triclosan (HS1), aloe barbadensis (HS8), chlorhexidine (HS9) and
hydrogen peroxide (HS12). Only one hand sanitizer with
Table 1 Log reduction values of various hand Sanitizers in the Kenyan market
isopropyl as the active ingredient was in single form (HS14)
and the rest were in combination form with triclosan
(HS10) and hydrogen peroxide (HS11) (Table 1).
Active ingredients and effectiveness of the hand sanitizers
Each of the two main active ingredients (ethanol and
isopropyl alcohol) had at least one product which demonstrated
99.9% bacterial reduction. Among the ethanol group, only
one product with 70% ethanol (HS13) demonstrated a
reduction factor of 5.9. The remaining alcohol products (HS2,
HS3, HS4, HS5, HS6 and HS7) did not mention the alcohol
concentration in the product ingredient list and these
products were poorly effective with an overall bacterial
reduction factor of less than 3 (Table 1). HS7 was more
effective against Pseudomonas aeruginosa than the other
poorly effective sanitizers whereas HS4 was more effective
against Escherichia coli than the rest (5.1 and 4.8 bacterial
reduction factors respectively) (Table 1).
Among the combined alcohol formulation, two products
demonstrated 5.9 overall reduction factor, one combined
with chlorhexidine (HS9) and the other combined with
hydrogen peroxide (H2O2) (HS12) (Table 1). On the other
hand, one product with alcohol and tricosan (HS1) was
effective against Escherichia coli (5.9 reduction factor), but
was not effective against the other two micro-organisms
Staphylococcus aureus and Pseudomonas aeruginosa; 3.1
and 3.8 respectively. One product with a combination of
ethyl alcohol and aloe (HS8) was the least effective among
all the products sampled with an overall reduction factor of
Alcohol aand Triclosan
Ethyl Alcohol and aloe barbadensis
Alcohol and Chlorhexidine
Isopropyl alcohol and Triclosan
Isopropyl alcohol and Hydrogen Peroxide
Ethyl Alcohol and Hydrogen Peroxide
70% Denatured alcohol
75% Isopropyl alcohol
aType of alcohol not specified
bLocally produced HS
less than 3. One product (HS14) out of three that
contained isopropyl as the only active ingredient had
5.9 reduction factor as compared to those with
isopropyl and tricosan (HS10) and isopropyl and hydrogen
peroxide (HS11) (Table 1).
Only those hand sanitizers that showed high reduction
factor when using the three bacteria strains were considered
to be the best and most effective. Based on WHO
Requirements for ABHRs (WHO Guidelines on Hand Hygiene in
Health Care  and (EN) 1500:), seven out of 14 hand
sanitizers (50%) had very low efficacy of less than 3
reduction factor, against all the three bacteria strains; Escherichia
coli, and Pseudomonas aeruginosa as compared to
Four hand sanitizers (HS12, HS9, HS13 and HS14)
showed 5.8 reduction factor on all three micro-organisms.
These results were comparable to those of the World
Health Organization (WHO) standard formula. Of these,
two were solution formulations and the two were gel
formulations, having active ingredients of either alcohol
with chlorhexidine or hydrogen peroxide (Fig. 2). A quarter
of the hand sanitizers were effective against only one
bacteria strain, for example, HS1 and HS4 were so effective
on E. coli; 5.8 and 4.8 respectively. Whereas HS7 was
effective on P. aeruginosa (4.8) (Fig. 2). Other sanitizers were not
effective in any bacteria, and HS8 was the least effective
with E. coli; 1.0, S. aureus; 0.9 and P. aeruginosa 1.5 (Fig. 2).
Ethanol-based gel formulations demonstrated higher
efficacy profiles than isopropyl alcohol based-gel formulation.
Organoleptic properties of the hand sanitizers
There were three organoleptic parameters tested in this
study; ease-of-use, general appearance and feeling on the
hand after use.
HS11 and HS12 were rated “very good” with a mean
of value of 4.1 ± 0.2 and 4.2 ± 0.2 respectively. Most hand
sanitizers (9/15) were rated as “good” with a mean range
of 3.0–3.9; these were hand sanitizers HS1, HS2, HS4,
HS5, HS7, HS9, HS10 and HS13, in the descending
order (Fig. 3). Four products were rated as “poor”, with a
mean range of 2.0–3.0 and they were hand sanitizer
HS3, HS8, HS6 and HS14 (Fig. 3).
Generally, in easy to use, hand sanitizer HS12 and
HS11 was rated the highest whereas hand sanitizer HS6
and HS14 was rated the least (Fig. 3).
None of the hand sanitizer had a mean of greater than 4.
Almost all hand sanitizers (13/15) were rated between 3.0
and 3.9. HS12 had the highest mean of 3.9 ± 0.2 followed
by hand sanitizer HS2 with a mean of 3.8 ± 0.2. In the lower
bracket, HS14 and HS9 had the least average rates of 2.19
± 0.1 and 2.92 ± 0.2 respectively (Fig. 3). There was only
one hand sanitizer (HS12) that scored “very good” (4.04 ±
0.2) based on how it felt on the hand after using it.
Comparing all the hand sanitizers and the parameters, it
was observed that HS1, HS2, HS10, HS11 and HS12 had
average rates that were more than 3.5 of all the three
parameters (Fig. 3). Some hand sanitizers had contrasting
mean of parameter, with one being poor and the other
good. For instance, HS6 in easy to use scored poorly
whereas in general appearance it was good. Similarly, HS14
scored very poorly on easy to use, poor on general
appearance and good on feeling on the hand after use (Fig. 3).
In general, when the three parameters were averaged
and compared, HS12 was rated very good with a score
of 4.1 and it was followed by HS11 with a score value of
3.9. The lowest were HS 14, 3, 6 and 8 (Fig. 3).
Use of hand sanitizers has gained popularity in Kenya in
the recent past. This has led to the development,
production and importation of several hand sanitizers by various
companies with the aim of commercialization as well as
supporting the health care system in preventing
transmission of pathogens.
Fig. 2 Log reduction of all hand sanitizers against the three bacteria strains
Fig. 3 Mean organoleptic comparison of different hand sanitizers in the market
Four out of 14 (28%) hand sanitizers (HS12, HS9, HS13
and HS14) that were subject of this study showed efficacy
profiles that were above the 60% IPA Reference Standard.
The four achieve the required high log reduction rate.
Seven out of 14 hand sanitizers (50%) had very low
efficacy of less than 3.0 against all the three bacteria and
hence failing to meet the Health Canadian Requirements
for ABHRs of log reduction of ≥3 using EN or ASTM
methods . All the poor performing were gel
formulations. This finding is in concordance with those of the
studies by Kramer et al.  and Dharan et al.  who
established that ethanol gel formulations, unless they have
been specially formulated and tested, are less efficacious
than ethanol solution formulations. Edmond and Macinga
 reported a study in Canada that demonstrated that
formulation of ABHRs had far greater influence on
efficacy than alcohol concentration alone. They established
that products having concentration of 70% performed
equally well and sometimes better than those with higher
concentration. It is this concern that led to the
development of solution-based alcohol formulations by WHO for
local production in the willing health institutions .
However, as demonstrated in this study the solution-based
alcohol formulations scored very poorly in terms
organoleptic properties in comparison with gel-based alcohol
formulations where the gel based brands HS11 and HS12
were rated as ‘very good’ while the WHO-formulation
(HS14) was rated as being ‘very poor’. It is notable that
the gel-based brands HS12 achieved both high efficacy
and desirable organoleptic properties.
The findings in this study that ethanol-based gel
formulation (HS12) have higher efficacy than isopropyl alcohol
based-gel formulations (HS11), this is contrary to what,
has been observed by other studies that isopropyl alcohol
solution has higher efficacy than ethanol solution .
The main limitation of this study is that we did not pick
all known hand sanitizers in Kenya, may be because they
were out of stock at the time of the study and the number
of hand sanitizers in the market was unknown. To the
best of our knowledge we tried as much as possible to
sample all hand sanitizers available. Secondly, the EN1500
protocol required that Fingertips of each hand kneaded
separately in 10 ml of broth with added neutralizers. We
did not add the neutralizers because some HS already
contained them. Not knowing the concentration of the
active ingredients for many of the products limited our
conclusion on the hand sanitizers that poorly performed.
In conclusion, this study established that 50% of the
selected ABHRs in the Kenyan market have the efficacy
values below that of International Reference Standard (60%
Isopropyl alcohol) and that some of those ABHRs with the
desired efficacy value have poor organoleptic
characteristics. There is a need to evaluate how many of these
products with <50% efficacy that have been incorporated
into the health system for hand hygiene and the country’s
policy on regulations on their usage.
We recommend that similar experiments to be conducted
to involve the other micro-organisms such as viruses and
fungi. Additionally, the efficacy studies in relationship to the
antimicrobial residual effect may be necessary too.
μl: Microliter; ABHRs: Alcohol-based hand rubs; CDC: Centers for Disease
Control and Prevention; CFU: Colony forming units; EN: European standard;
HAIs: Hospital associated infections; HS: Hand sanitizer; HS1- HS14: Codes of
hand sanitizers; ICUs: Intensive care units; IPA: Isopropyl alcohol;
KEMRI: Kenya Medical Research Institute; RF: Bacterial logarithmic reduction
factors; SSC: Scientific Steering Committee; TSA: Tryptic soy agar;
WHO: World Health Organization
We would like to thank all the staff at KEMRI Production Department
especially S. Muchiri, A. Mwangi, E. Kerubo, Doris Night and P. Kaiguri
(retired), for the support they accorded us in carrying out this study. We
would also like to thank Director KEMRI for providing the necessary moral
and financial support to execute this study as well as the permission to
publish this work. Finally, we acknowledge support from staff of the CDC
Atlanta and Kenya for their great support.
This study was jointly funded by KEMRI and by the United States Government
through the CDC- iFund project, which was awarded to Linus Ndegwa.
Availability of data and materials
The data and the materials are freely available to any scientist wishing to use them.
LM, KT, CJ, JH, MO (KEMRI) were all involved in conceptualization and project
design, MO, LM, JH (KEMRI), LN (CDC), were project leaders, SO, FW, SM, KT,
LM and MO performed the experiments. LM and KT prepared the samples,
MO, JH, LM entered the data and analyzed. MO, JH, LM, KT and LN prepared
the manuscript. MO submitted the manuscript. All authors read and
approved the final manuscript.
This study was conducted as part of the authors’ usual employment. No
author received outside support or funding to conduct this study.
Consent for publication
The consent for publication was obtained from KEMRI publication committee
(Ref. No. KEMRI/CBRD/PUB/001/01), CDC – Atlanta (CGH tracking #2016-084)
and the study participants.
Ethical approvals and consent to participants
The study protocol was approved by the KEMRI Scientific Steering Committee
(Reference Number SSC No. 2190) and the participants gave their consent
before they were engaged in the study.
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