Nasal carriage, risk factors and antimicrobial susceptibility pattern of methicillin resistant Staphylococcus aureus among healthcare workers in Adigrat and Wukro hospitals, Tigray, Northern Ethiopia
Legese et al. BMC Res Notes
Nasal carriage, risk factors and antimicrobial susceptibility pattern of methicillin resistant Staphylococcus aureus among healthcare workers in Adigrat and Wukro hospitals, Tigray, Northern Ethiopia
Haftom Legese 0 1
Atsebaha Gebrekidan Kahsay 0
Amlisha Kahsay 0
Tadele Araya 0
Gebre Adhanom 0 1
Saravanan Muthupandian 0
Araya Gebreyesus 0
0 Department of Microbiology and Immunology, Institute of Biomedical Sciences, College of Health Science, Mekelle University , Mekelle , Ethiopia
1 Department of Medical Laboratory, College of Medicine and Health Science, Adigrat University , Adigrat , Ethiopia
Objective: The aim of this study was to determine nasal carriage, risk factors and antimicrobial susceptibility pattern of methicillin resistant Staphylococcus aureus among health care-workers of Adigrat and Wukro hospitals Northern Ethiopia. Results: The overall prevalence of S. aureus and methicillin resistance S. aureus (MRSA) in the present study were 12% (29/242) and 5.8% (14/242) respectively. The rate of MRSA among S. aureus was 48.3%(14/29). In this study, MRSA carriage was particularly higher among nurse professionals (7.8%) and surgical ward (17.1%). None of the MRSA isolates were sensitive to penicillin and ampicillin. However, low resistance was found for chloramphenicol and clindamycin. Being diabetic and use of hands rub was statistically significant with MRSA colonization.
Antimicrobial susceptibility test; Health care workers; methicillin resistance Staphylococcus aureus; nasal carriage; Staphylococcus aureus
Staphylococcus aureus is known to be the cause of
hospital and community acquired infections [
resistant S. aureus (MRSA) causes a significant problem
of the world and major health care associated pathogen
]. About 10–35% world population harbors MRSA
in their anterior nares . The emergence of MRSA is
an important hospital acquired pathogen continues to
remain a significant factor for failure of patient
management worldwide [
Increasing rates of antibiotic resistance owing to an
incautious use of antimicrobials lead to decrease
treatment options for MRSA infection [
]. The increasing of
MRSA strains becomes a public health problem [
has a negative effect on the treatment cost, long
hospitalization, and increased morbidity and mortality
especially among the critically ill patients [
]. The problem of
MRSA is observed all over the world, although, the
burden of infection is high in developing countries [
High MRSA carriages of health care professionals have
been reported as the key mechanism of transmission
among patients during treatments, patients contact and
aerosolization following sneezing [
]. Health care
workers who have direct contact between the community and
hospital may serve as the agents of the
cross-transmission of the community acquired and hospital acquired
Knowledge of MRSA prevalence and recent
antimicrobial susceptibility pattern is very important for
appropriate selection of the antimicrobial agents [
]. However, in
most hospitals of African countries, there is neither
surveillance system nor control policy for MRSA, this plays
significant role for increasing the problem [
Therefore, this current study was aimed to determine
nasal carriage, antimicrobial susceptibility patterns and
associated factors of MRSA colonization among
healthcare workers in Adigrat and Wukro hospitals, Tigray,
northern Ethiopia. This evidence based information in
the study area will contribute a role for the prevention
and control of MRSA by responsible bodies.
Study area and study design
This study was carried out in Wukro and Adigrat
general hospitals. Those hospitals are found in eastern zone
of Tigray region and are located about 824 and 900 km
respectively north of Addis Ababa (Capital city of
Ethiopia). Wukro and Adigrat general hospitals have a total
staffs 313 among those 41.3% are males and 58.7% are
female, and are serve for the total population of 755,343.
A cross sectional study was carried out among 242 health
care workers from September to December 2016.
Isolation and identification
Swabs were inoculated on Manitol Salt agar (MSA)
(Oxid, UK) and incubated at 37 °C for 24 h and sub
cultured into blood agar. All positive culture was identified
by their characteristics appearance and biochemical test
using standard procedure. Colonies that were
Manitol fermented (golden yellow colonies), β-hemolytic on
blood agar were considered as S. aureus and was
confirmed by Coagulase test as positive [
Antimicrobial susceptibility testing
Antimicrobial susceptibility testing was performed using
modified Kirby–Bauer disc diffusion method on Muller–
Hinton agar (MHA; Oxoid, UK) according Clinical and
Laboratory Standards Institute (CLSI, 2016) guidelines
]. From overnight grown colonies on nutrient agar 3–5
well-isolated colonies were emulsified in 3–4 ml of sterile
physiological saline to get bacterial inoculums
equivalent to 0.5 McFarland turbidity standards. After that the
antibiotic discs were placed manually on the medium
and incubated at 37 °C for about 18 h and the zones of
inhibition was measured using caliper. The
interpretation of the results was made based on the CLSI criteria
as sensitive, intermediate and resistant [
discs (30 μg), penicillin (10 μg), ampicillin (10 µg),
erythromycin (15 µg), cotrimoxazol (25 µg), chloramphenicol
(30 µg), gentamycin (10 µg), kanamycin (30 µg),
amikacin (30 µg), ciprofloxacin (5 µg), tetracycline (30 µg), and
clindamycin (2 µg) (Oxoid, UK). All isolates resistant to
cefoxitin was considered as MRSA [
Data processing and analysis
The findings were statically analyzed using descriptive
statistics, Chi square test (χ2) and p < 0.05 was considered
as statistically significant. The variables from the
demographic and associated risk analysis were performed
using SPSS (version 22) package.
A total of 242 health professionals were included in the
study. The age of study participants ranged from 20 to
59 years with mean age of 31.78 ± 8.9 years. One hundred
forty-two (58.7%) were females and 100 (41.3%) were
males. The mean number of their work experience was
Prevalence of Staphylococcus aureus and MRSA
The prevalence of S. aureus and MRSA in this study was
12% (29/242) and 5.8% (14/242) respectively. The
prevalence of MRSA among nurse, doctor and midwife
professionals were 10 (7.8%), 1 (7.7%), and 2 (6.7%) respectively.
The highest rate of S. aureus and MRSA observed in
surgical ward were 7 (20.0%) and 6 (17.1%) respectively
(Additional file 1: Table S1).
Risk factors associated for MRSA colonization
Chi square test (χ2) showed that use of hand rub
(p < 0.001), and being a diabetic (p < 0.001), were
statistically significant with MRSA colonization (Table 1).
Antimicrobial susceptibility patterns of Staphylococcus aureus
The antimicrobial Susceptibility patterns were performed
for the 29 S. aureus isolates against 12 antimicrobials. Of
the 29 isolates, 93.1% showed resistance to penicillin
followed by kanamycin 19 (65.5%), erythromycin 18 (62.1%),
tetracycline 16 (55.2%) cotrimoxazole 15 (51.7%),
ampicillin 14 (48.3%), and amikacin 13 (44.8%). Low resistance
were found for chloramphenicol 5 (17.2%) and
clindamycin 5 (17.2%). None of the isolates were intermediate
resistance (Fig. 1).
Antimicrobial susceptibility pattern of methicillin resistance
S. aureus (Additional file 2: Figure S1, Additional file 3: Table S2)
Multidrug resistance of Staphylococcus aureus
isolates According to Magiorakos et al. [
resistance in this study was considered as resistance to
three or more of the antimicrobial class tested.
Twentytwo (75.9%) of all the isolates were multi-drug resistant,
*Statistically significant with MRSA colonization
NB: use of hand rub is use of a waterless alcohol [
five isolates were resistant for three and two isolates were
resistant for ten antimicrobials (Table 2).
The overall nasal carriage of S. aureus in the present
study was 12%. This is supported by study carried out in
India (14%) [
]. However, lower than that of reported
from Ethiopia, (28.8%) [
], Democratic Republic Congo
], Gaza Strip (31.1%) [
] Pakistan (48%) [
China (25.3%) [
] and Iran (25.7%) [
The total prevalence of MRSA in this study was 5.78%.
This was similar with results from [
], France (5.3%)
], Asia (6.1%) [
] and Iran (5.3%) [
]. However, it
was lower compared with the study revealed in Ethiopia,
Mekelle (14.1%) [
] and Dessie (12.7%) [
], Egypt (20%)
], Nigeria (39.9%) [
], Gaza Strip (25.5%) [
Pakistan (13.95%) [
]. On the other hand, our result was
higher than study reported from and China (1.0%) [
This variations of prevalence among different study areas
might be due to difference in rate of patient admission,
study period [
], microbiological methods (from sample
size to culture media) antimicrobial policy, in addition
to that, variety levels of commitment to infection
prevention measure among hospitals, and awareness of the
health care worker about MRSA may contribute to the
In current study, MRSA carriage was relatively higher
among nurses (7.8%) followed by doctors (7.7%). This is
consistent with study conducted in Ethiopia, Dessie [
Gaza Strip [
] and India [
]. MRSA carriage was
particularly high among surgical ward (17.1%) this result
is comparable with corresponding study in Gaza Strip
] and Dessie (35%) [
]. This result might be
explained by the frequent direct physical contact of
doctors and nurses with patients and increase workload in
In this study, use of hands was statistically significant
with MRSA colonization. Health care workers rarely used
hand rub were high proportion to have MRSA
colonization on their anterior nare than those who were used
hand rub usually and always. This finding is in line to
previous studies in America [
], France [
]. The temporary hand carriage of bacteria on the
hands of health professionals could account for the major
mechanism for the auto-transmission from contaminated
hand to nose.
The present study, found that being diabetic patients
was statistically associated with MRSA colonization.
Health care workers with diabetic were high proportion
to have MRSA colonization on their anterior nare. This
an ) 60
PEN penicillin, AMP ampicillin, GM gentamycin, AK amikacin, CHL
chloramphenicol, CIP ciprofloxacin, TTC tetracycline, TS cotrimoxazol, DA
clindamycin, ERY erythromycin, K kanamycin, CXT cefoxitin
MDR multidrug resistant; MDR definition for S. aureus percent is computed from
total number of S. aureus
was in line with studies from Tanzania [
] Iran [
]. This may be due to diabetic patients reduced
immunity which fails to combat the pathogens [
In the current study, there was no statistically
significant of MRSA with educational status, hand washing
habit, prior hospitalization, history of antibiotic
treatment, and presence of chronic obstructive pulmonary
disease in this study. This was in agreement with a result
obtained in Ethiopia [
] and other studies conducted in
other parts of the world [
8, 20, 27
Concerning antimicrobial susceptibility patterns of
MRSA isolates, clindamycin and chloramphenicol were
effective against MRSA isolates. However, increasing
resistance was observed in our finding which is
consistent with study reported from Pakistan ampicillin,
penicillin, erythromycin, amikacin and ciprofloxacin (100%),
(100%), (66%), (44%), and (33%) respectively [
Cotrimoxazole also showed a similar result compared with
corresponding reports of Dessie (66.7%) [
slight differences in the reported figures, the
susceptibility patterns of antimicrobial were in line with the study
from Nigeria for gentamycin 50 (63.3%), erythromycin
55 (69.6%) and Ciprofloxacin 32 (40.5%) [
], in India
] for ciprofloxacin (34.6%) and erythromycin (54.8%),
chloramphenicol (16.1%) from Serbia [
], and penicillin
(93%) reported from India [
Higher susceptibility was also showed in the present
study as compared to a result from health care
workers at Iran for gentamycin (69%), clindamycin (69%),
and ciprofloxacin (66%) [
]. Kanamycin also showed
lower resistance compared with similar study in Serbia
]. On the other hand, our finding was higher
compared to studies conducted in India [
ciprofloxacin (20%), and Gaza Strip erythromycin, tetracycline,
gentamycin, clindamycin, and ciprofloxacin (19.6%),
(9.8%), (3.9%), (3.92%), and (3.92%) respectively [
This resistance pattern of our finding might be due to
excessive use of this antibiotics for many other
infections and replacing of sensitive strains by resistance
strains at the hospital settings.
Drug susceptibility test on all the 29 S. aureus isolates
against 12 commonly used antibiotics were performed.
The resistance of strains against penicillin,
ciprofloxacin, and erythromycin is consistent with studies
conducted in Ethiopia, Dessie [
], and Nepal [
cotrimoxazole (81.7%) and gentamycin (60.4%) were
higher than our finding. However, lower resistance was
observed with cotrimoxazole (33%), and gentamycin
(27%) conducted in India [
], and 25% for gentamycin
in Nepal [
]. This might be due to the variation in the
geographical area, and local infection prevention and
control strategies of the hospital settings.
Studies conducted in Ethiopia and China has
reported higher resistance patterns to tetracycline
(71.4%), chloramphenicol (57.1%) [
] and clindamycin
]. Where as lower resistance than our finding
to amikacin was reported from India [
], Nepal [
and Pakistan [
]. In the present study higher
resistance were showed for tetracycline, cotrimoxazol and
gentamycin compared with study conducted in India
]. In our study area, penicillin, ampicillin and
erythromycin are the commonly prescribed antibiotics. This
might have contributed for the resistance against these
In this study high prevalence of multi drug resistance
to wards S. aureus was observed. Of the total isolates 22
(75.9%) were resistant to three and above class of
]. Fourteen of them (63.6%) were MRSA
and comparable susceptibility was observed in a study
from Ethiopia, Dessie [
]. This increased multi drug
resistance might be due to continuous genetic variation
of strains by mutation, or cross transmission of the a
resistance genetic elements from one to another
bacterium, overcrowded wards, and prescribed of antibiotics
without culture and sensitivity [
The present study, the overall prevalence of MRSA
in the study area was found to be 5.78%. The carriage
rate MRSA was worse among nurses and working in
surgical wards. Rarely used hand rub and being
diabetics were statistically significant with MRSA
colonization. Clindamycin and chloramphenicol were
sensitive antimicrobials for the treatment of MRSA and
S. aureus. The majority of the S. aureus isolates were
Limitation of the study
The infection is due to community or hospital acquired
strains could not be identified. More sensitive and
specific molecular techniques could not be used to identify
the species and strain typing of S. aureus.
Furthermore, for the future researcher phenotypic and
genotypic studies are needed to establish and clarify the
genetic mechanism behind susceptibilities to antibiotics.
Additional file 1: Table S1. Prevalence of S. aureus and MRSA among
health professionals in Adigrat and Wukro hospitals, Tigray, Northern
Ethiopia September–December 2016.
Additional file 2: Figure S1. Antibiotic Susceptibility pattern of
Methicillin Resistant Staphylococcus aureus strains to other antibiotics tested
at Adigrat and Wukro hospitals, Tigray, Northern Ethiopia September–
December 2016 (n = 14).
Additional file 3: Table S2. Antimicrobial susceptibility pattern of MRSA
and MSSA isolates from health professionals at Adigrat and Wukro
hospitals, Tigray, Northern Ethiopia September–December 2016.
AST: antimicrobial susceptibility testing; CLSI: Clinical and Laboratory
Standards Institute; MDR: multi-drug resistance; MRSA: methicillin resistant
Staphylococcus aureus; MSSA: methicillin sensitive Staphylococcus aureus.
HL designed the study, collection, analysis, and interpretation of data, and
drafted the manuscript. AG, AGK, and AK designed the study, supervised data
collection both on field and in laboratory, and prepared the manuscript. All
authors read and approved the final manuscript.
The authors gratefully acknowledge the health care workers of study area for
their participation on study. We also wish to extend our deep appreciation to
Mekelle University, College of Health Sciences for providing us the
opportunity to do this thesis writing, and allowing the laboratory space with material
The authors declare that they have no competing interests.
Availability of data and materials
All data collected and analyzed during this study were included in the
manuscript. But if the full paper is needed, it will be shared upon request by the
editor from the corresponding author.
Consent for publication
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