Prevalence and antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus among janitors of Mekelle University, North Ethiopia
Kahsay et al. BMC Res Notes
Prevalence and antimicrobial susceptibility patterns of methicillin-resistant Staphylococcus aureus among janitors of Mekelle University, North Ethiopia
Atsebaha Gebrekidan Kahsay 0
Dawit Gebreegziabher Hagos 0
Getahun Kahsay Abay 0
Tadele Araya Mezgebo 0
0 Department of Medical Microbiology and Immunology, Institute of Biomedical Sciences, College of Health Sciences, Mekelle University , Mekelle , Ethiopia
Objective: The objective of this study was to determine the prevalence of methicillin-resistant Staphylococcus aureus and antimicrobial susceptibility patterns among janitors working at Mekelle University, Tigray, Northern Ethiopia. Result: The overall prevalence of S. aureus and MRSA in the present study were 17.97% (69/384) and 6.25% (24/384) respectively. Although not statistically significant, the prevalence of MRSA among janitors working in the medical area (9.7%, 10/103) was two times higher than the non-medical area (4.9%, 14/281). Janitors who had more service year and who were unable to read and write were found with high isolates of MRSA. Nasal carriage of MRSA among janitors who work in the hospital and who were hospitalized in the last 3 months and those who had exposure to wastes and body fluids were 13 (37.1%) and 10 (38.5%) respectively. Majority of the isolates of S. aureus were sensitive to ciprofloxacin (67; 97%), doxycycline (56; 81%), erythromycin (54; 78%), chloramphenicol (50; 72.5%) and cefoxitin (45; 65.2%). Sixty-seven of the 69 (97%) were resistant to penicillin. Of the 69 isolates of S. aureus, 22 (31.9%) showed multidrug resistant. Fourteen were resistant to three antimicrobials, 2 were resistant to four antimicrobials, and 7 were resistant to five antimicrobials.
Mekelle University; Methicillin resistant Staphylococcus aureus; Janitors; Antimicrobial susceptibility tests
Staphylococcus aureus, a Gram-positive spherical-shaped
bacterium, predominantly colonizes the skin and nasal
mucosa of healthy individuals globally [
28% of healthy adult individuals have their anterior nares
persistently colonized with this bacterium (https://www.
Person to person transmission of S. aureus occurs mostly
through contact with fluids from infected skin
]. Infections due to S. aureus range from simple
skin infections to fatal bacteremia and pneumonia [
aureus contributes to one-third of surgical site infections
and close to a quarter of ventilator-associated pneumonia
]. Between 2001 and 2009, the S. aureus skin and soft
tissue infections associated hospitalization has increased
from 39 to 51% in hospitals of USA [
With the emergence of methicillin-resistant S. aureus
(MRSA) first recognized from hospitalized patients in
], the treatment of Staphylococcal infections has
become more challenging [
]. Until 1990, could only be
described as a hospital-acquired infection [
Subsequently, MRSA has become a major global public health
problem in both hospitals [
] and community [
settings globally. Among hospitals and non-medical
janitors in Taiwan, 3.6 and 1.3% have MRSA in their nares
]. In Pakistan, 13.6% of sanitary and 2.1%
administrative workers were found to have MRSA in
their nares respectively [
]. The nasal carriage of MRSA
among 600 randomly selected health workers in Iran was
Thirty-four (28.8%) and 15 (12.7%) healthcare
workers in Dessie-Ethiopia had their anterior nares colonized
with S. aureus and MRSA respectively [
(59%) and 44 (28.9%) in patients in Jimma-Ethiopia had
their anterior nares colonized with S. aureus and MRSA
At Mekelle Hospital-Ethiopia, the nasal and hand
carriage of MRSA among healthcare workers was 20.3% [
In Ethiopia, as to our knowledge, despite its
importance, there is no published data that indicates the
prevalence of MRSA and antimicrobial susceptibility patterns
among janitors of any institution.
Therefore, this research project assessed the prevalence
of MRSA and its antimicrobial susceptibility patterns
among janitors working in Mekelle University; with a
view to providing information to aid the design of
appropriate prevention strategies.
Materials and methods
Study area and study design
Mekelle University is one of the largest Universities in
Ethiopia. It has more than 30 thousand first-degree,
second-degree and third-degree annual students in the
five campuses [
]. It conducts teaching, research, and
community activities. There are 576 janitors working at
Mekelle University (155 from one campus in Ayder
comprehensive specialized hospital and 421 from other four
campuses of the University. A cross-sectional study was
conducted from January to May 2016.
Sample size and sampling technique
A total of 384 janitors (103 from medical and 281 from
non-medical) were recruited to participate in the study.
The sample size was calculated using single proportion
formula (P = 0.5, Zα/2 = 0.196, CI = 95). Simple random
sampling technique was used to select 384 study
participants. Study participants who had nasal bleeding at the
time of data collection were excluded because rolling of
swab may aggravate bleeding.
Data collection and processing
Trained data collectors were recruited to collect the
socio-demographic, clinical and other factors from
consenting participants using a standardized questionnaire.
The questionnaire could be self-administered (for literate
participants) or interview-administer (for participants
unable to read and write their mother language).
Sample collection, transport, and processing
Using aseptic procedures, trained study assistants took
nasal swab samples from both anterior nares of the
study participants which were transported to Mekelle
University College of Health Sciences department of
medical microbiology laboratory within 30 min of
collection. Upon arrival, specimens were inoculated on
to Mannitol salt agar (HI Media Laboratories, Pvt.
Mumbai, India) and incubated at 37 °C for 24 h. After
incubation, the presence of S. aureus was confirmed by
golden yellowish colonies, Gram stain and a
biochemical test using slide coagulase test [
Antimicrobial susceptibility tests
Isolates identified as S. aureus were subjected to
antimicrobial susceptibility tests using the Kirby Bauer
disk diffusion method as described by CLSI [
antimicrobials were used; these were penicillin (10
units), erythromycin (15 μg), chloramphenicol (30 μg),
doxycycline (30 μg), ciprofloxacin (5 μg) and cefoxitin
(30 μg). Three to five colonies of S. aureus were picked
from the nutrient agar to make a suspension that was
standardized to 0.5 McFarland standards. Using
sterile applicator cotton swab, standardized suspensions
were swabbed on to the Muller Hinton agar. The
antimicrobial discs were placed then on the Muller
Hinton agar within 20 min using aseptic technique. The
Muller Hinton agar plates were incubated at 35 °C for
18 h. After this, the diameter of the “zone of inhibition”
around the antibiotic discs was measured using calipers
and reported as sensitive, intermediate and resistance
Methicillin resistance S. aureus was confirmed by 30 μg
cefoxitin disc. A “zone of inhibition” of ≤ 21 mm was
considered as methicillin-sensitive and a “zone of inhibition”
of > 22 as methicillin-resistant.
Each lot and shipment of the medium was checked
for expiration dates prior to use as part of quality
control. The performance of the media and antibiotic
discs were evaluated using positive controls (S. aureus,
ATCC-25923) and negative controls (Escherichia
Frequency and percentage were used to summarize
categorical data. Chi square statistics were used to describe
associations between various participants’
characteristics and Staphylococcus nasal carriage. The level of
significance was set at α = 0.05 using the two-tailed method.
SPSS for Windows Version 20 software was used for the
statistical analysis of the collected data.
Ethical approval was obtained from the Ethical Review
Committee of Mekelle University, College of Health
Sciences with a proposal number of ERC 0682/2015.
Informed consent was collected from each study
participants after they understood the aim of the study. As the
janitors were outsourced to a private company,
permission was collected from the private limited company.
Three hundred and eighty-four participants were
recruited. Their mean age was 21 (±4.97) years and all
(100%) were female. The majority (85.2%; 327) were
aged 18–24 years. The majority were single (81.8%), had
attained a high school education; grade 9–12 (53.1%) and
lived with children aged < 15 years (52.6%).
Majority (63%) had served as a janitor for less than
1 year, in a non-medical area (73.1%), did not suffer from
allergic rhinitis (95.3%), had not had a skin infection
(97.1%), nor a wound infection (94.8%), nor been
hospitalized (64.3%) in the 3 months preceding the interview.
The majority (73.2%) reported no history of exposure to
waste and body fluids (Table 1).
Isolation of S. aureus from participant’s samples
Samples were collected from the anterior nares of all
participants; S. aureus was cultured from 69 (17.97%)
of the samples. Of the 69 isolates, 25.2% (26/103) were
recovered from janitors that worked in medical areas and
15.3% (43/81) from those that worked in non-medical
areas of the University (Table 1).
Prevalence of MRSA among janitors working at Mekelle
Among participants with positive isolates (n = 69), 24
(34.8%) had methicillin resistant S. aureus. Ten of the 26
isolates (38.5%) were among janitors working in medical
areas where as 14/43 (32.6%) was working in
non-medical areas. The overall prevalence of MRSA was 6.25%
(24/384) (Table 1).
Antimicrobial susceptibility patterns of S. aureus isolates
All the 69 S. aureus isolates were subjected to
antimicrobial susceptibility tests against seven antimicrobials.
Majority of the isolates of S. aureus were sensitive to
ciprofloxacin (67; 97%), doxycycline (56; 81%),
erythromycin (54; 78%), chloramphenicol (50; 72.5%) and cefoxitin
(45; 65.2%). Sixty-seven of the 69 (97%) were resistant
to penicillin. About one-third 24 (34.8%) of the isolates
were resistant to cefoxitin. Of the 45 methicillin
susceptible S. aureus, 2 (4.4%), 5 (11.1%), 6 (13.3%), 6 (13.3%) and
43 (95.6%) were resistant to ciprofloxacin, doxycycline,
erythromycin, chloramphenicol, and penicillin
respectively (Table 2).
Multidrug resistance (MDR) isolates of S. aureus
Of the 69 isolates of S. aureus, 22 (31.9%) isolates showed
MDR. Fourteen were resistant to three antimicrobials, 2
were resistant to four antimicrobials, and 7 were resistant
to five antimicrobials (Table 3).
Factors associated with MRSA colonization of the anterior nares among janitors at Mekelle University
A significantly higher proportion of participants with S.
aureus colonization was found among participants who
were unable to read or write compared to those who had
attained junior secondary, high school and diploma level
education (62.5% vs. 47.1, 18.2, and 45.5% respectively);
among participants that had served as janitors for more
than 2 years compared to those who had served for less
than 1 year and for between one and 2 years (62.5% vs.
39.5% and 11.1% respectively) (Table 1).
Staphylococcus aureus was isolated from the nasal swab
of one study participants who had allergic rhinitis and
was resistant to cefoxitin/methicillin. Nasal carriages of
MRSA among janitors who work in the hospital and who
were hospitalized in the last 3 months and those who had
exposure to wastes and body fluids were 13 (37.1%) and
10 (38.5%) respectively (Table 1).
The overall prevalence of S. aureus and MRSA in this
study were 69 (17.97%) and 24 (6.25%). This is lower than
the study carried out among hospital personals in
] and school children and prisoners in
], but similar to the study revealed from
healthcare workers in Iran [
Staphylococcus aureus was found to be colonized in 26
(25.2%) janitors working in medical and 43 (16%) in
nonmedical area, whereas MRSA revealed from 10 (9.7%) in
medical and 14 (4.9%) non-medical area. This is higher
than the study carried out in Taiwan [
]. This may be
due to difference in personal hygiene.
Above 85% of the janitors working in the university
were youth (18–24 years). The other below 15% was
above 24 years and was found to be with high carriage of
MRSA 4 (40%). This is comparable with the study among
prisoners in Jimma-Ethiopia [
]. Above 70% of the
janitor were high school and diploma but high prevalence of
MRSA 5 (62.5%, P = 0.038) were revealed among janitors
who were unable to read and write in which transmission
may be high. This might be due to lack of awareness in
N total isolates of MRSA, n total number of MSSA isolates
a Methicillin resistance S. aureus
b Methicillin sensitive S. aureus
using safety measures available in the medical area
during work (exposure to wastes) and may have hand nasal
contact that can lead to increase the MRSA. About 62%
of the participants were served below 1 year as a janitor,
however, MRSA carriage was raised among the janitors
who served above 2 years 5 (62.5%, P = 0.023).
None of the participants were presented with
underlying diseases except eighteen participants with allergic
rhinitis and one of whom having allergic rhinitis had
MRSA which is not statistically significant. This is
different from a study conducted in Taiwan [
]. Janitors were
also requested to respond to the occurrence of
respiratory infection, skin infection and present of wound,
hospital stay and hospitalization in the last 3 months. The
carriage rate of MRSA among the janitors having
respiratory, skin infection and present with wound were 1
(100%), 4 (100%) and 2 (33.3%) respectively. This is unlike
to the study reported from Taiwan [
MRSA isolates were 100% resistant to penicillin and
cefoxitin which is similar to the study reported from
]. 24 (100%), 16 (66.7%), 15 (62.5%), and 11
(45.8%) isolates of MRSA were sensitive to
ciprofloxacin, erythromycin, doxycycline, and chloramphenicol
Six of the isolates of MRSA (8.6%) were resistant
to five antimicrobial drugs and the resistant patterns
Methicillin-resistant S. aureus was isolated from both
medical and non-medical area. Even though there was
no statistically significant difference, the proportion
of MRSA isolated from the medical area was two times
higher than the non-medical area. Participants who were
unable to write and read and those who have at most
service year were presented to acquire more MRSA and
have the statistically significant difference.
More than 30% of confirmed MRSA isolates were
resistant to most of the antimicrobial drugs tested in the
present study; however, no resistance was recorded from
Janitors who were unable to write and, having more
services and serving in the hospital should get awareness
on the impact of MRSA and its transmission especially
in relation to the hospital patients during cleaning of
This study limited to conduct the MRSA gen as well as
some additional antimicrobial agents.
S. aureus: Staphylococcus aureus; MRSA: methicillin resistance Staphylococcus
aureus; SPSS: Statistical Package for Social Sciences; MDR: multidrug resistance;
ERC: Ethical Review Committee; USA: United States of America; CI: confidence
interval; ATCC: American type culture collection; CLSI: Clinical Laboratory
AGk, DGH, GKA, and TAM involved in designing of the project, collection of
data, data analysis and interpretation, and write up of the manuscript. AGK
and DGH designed the study, supervised data collection both on field and in
laboratory, and prepared the manuscript for publication. All authors read and
approved the final manuscript.
We would like to thank officials and study participants of the study sites for
their cooperation during data collection by providing and/or facilitating the
collection of valuable information.
The authors declare that they have no competing interests.
Availability of data and materials
All data analyzed during this study are included in the published article.
Consent for publication
Ethics approval and consent to participate
The study was ethically approved by the Ethical Review Committee of Mekelle
University College of Health Sciences. Informed consent was collected from
each study participants after they understood the aim of the study.
Mekelle University (CRPO/CHS/015/08).
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