ORIGINAL RESEARCH
published: 19 May 2022
doi: 10.3389/fmicb.2022.894319
Diarrhea-Causing Bacteria and Their
Antibiotic Resistance Patterns
Among Diarrhea Patients From
Ghana
Theophilus Afum 1, Diana Asema Asandem 1, Prince Asare 1, Adwoa Asante-Poku 1,
Gloria Ivy Mensah 1, Abdul Basit Musah 1, David Opare 2, Kiyosi Taniguchi 3,4,
Nuhu Muniru Guinko 2, Thelma Aphour 2, Doris Arhin 2, Koichi Ishikawa 5, Tetsuro Matano 3,5,
Taketoshi Mizutani 3, Franklin Asiedu-Bekoe 2, Hiroshi Kiyono 3,4,6,
Abraham Kwabena Anang 1, Kwadwo Ansah Koram 1 and Dorothy Yeboah-Manu 1*
Edited by:
Steven Lee Foley,
National Center for Toxicological
Research (FDA), United States
Reviewed by:
Morteza Saki,
Ahvaz Jundishapur University of
Medical Sciences, Iran
Madubuike U. Anyanwu,
University of Nigeria,
Nsukka, Nigeria
*Correspondence:
Dorothy Yeboah-Manu
dyeboah-manu@noguchi.ug.edu.gh
Specialty section:
This article was submitted to
Antimicrobials, Resistance and
Chemotherapy,
a section of the journal
Frontiers in Microbiology
Received: 11 March 2022
Accepted: 26 April 2022
Published: 19 May 2022
Citation:
Afum T, Asandem DA, Asare P,
Asante-Poku A, Mensah GI,
Musah AB, Opare D, Taniguchi K,
Guinko NM, Aphour T, Arhin D,
Ishikawa K, Matano T, Mizutani T,
Asiedu-Bekoe F, Kiyono H,
Anang AK, Koram KA and
Yeboah-Manu D (2022) DiarrheaCausing Bacteria and Their Antibiotic
Resistance Patterns Among Diarrhea
Patients From Ghana.
Front. Microbiol. 13:894319.
doi: 10.3389/fmicb.2022.894319
1
College of Health Sciences, Noguchi Memorial Institute for Medical Research, University of Ghana, Accra, Ghana, 2 Ghana
Health Service, Accra, Ghana, 3 The Institute of Medical Science, The University of Tokyo, Tokyo, Japan, 4 Graduate School of
Medicine, Institute for Global Prominent Research, Chiba University, Chiba, Japan, 5 Joint Research Center for Human
Retrovirus Infection, Kumamoto University, Kumamoto, Japan, 6 Department of Medicine, CU-UCSD Center for Mucosal
Immunology, Allergy and Vaccines (cMAV), University of California San Diego, San Diego, CA, United States
Diarrheal disease remains a major global health problem particularly in children under
5 years and the emergence of antibiotic-resistant strains of causative pathogens could
slow control efforts, particularly in settings where treatment options are limited. This
surveillance study conducted in Ghana aimed to determine the prevalence and antimicrobial
susceptibility profile of diarrhea-causing bacteria. This was a cross-sectional study carried
out in five health facilities in the Ga West Municipality of Ghana between 2017 and 2021.
Diarrheic stool samples from patients were collected and cultured on standard differential/
selective media and isolates identified by standard biochemical tests, MALDI-TOF assay,
and serological analysis. The antibiogram was determined using Kirby-Bauer disk diffusion
and Microscan autoScan4 MIC panels which were used for extended-spectrum betalactamase (ESBL) detection. Bacteria were isolated from 97.5% (772/792) of stool
samples, and 167 of the isolates were diarrheagenic and met our inclusion criteria for
antimicrobial resistance (AMR) analysis. These included Escherichia coli (49.1%, 82/167),
Salmonella species (23.9%, 40/167), Vibrio species (16.8%, 28/167), and Shigella species
(10.2%, 17/167). Among 24 Vibrio species, we observed resistances to cefotaxime (21/24,
87.5%), ceftriaxone (20/24, 83.3%), and ciprofloxacin (6/24, 25%), including four multidrug resistant isolates. All 13 Vibrio parahaemolyticus isolates were resistant to cefazolin.
All 17 Shigella isolates were resistant to tetracycline with resistance to shigellosis drugs
such as norfloxacin and ciprofloxacin. Salmonella isolates were highly susceptible to
norfloxacin (40/40, 100%) and tetracycline (12/34, 35%). Two ESBL-producing E. coli
were also identified with marked susceptibility to gentamicin (66/72, 91.7%) and amikacin
(57/72, 79.2%) prescribed in the treatment of E. coli infections. This study showed the
different bacteria implicated in diarrhea cases in Ghana and the need for differential
diagnoses for better treatment outcomes. Escherichia coli, Shigella, Salmonella, and Vibrio
Frontiers in Microbiology | www.frontiersin.org
1
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
have all been implicated in diarrhea cases in Ghana. The highest prevalence was E. coli
and Salmonella with Shigella the least prevalent. Resistance to commonly used drugs
found in these isolates may render bacteria infection treatment in the near future nearly
impossible. Routine antimicrobial susceptibility testing, effective monitoring, and nationwide
surveillance of AMR pathogens should be implemented to curb the increase of antimicrobial
resistance in Ghana.
Keywords: diarrhea, bacteria, resistance, antimicrobial, susceptibility
INTRODUCTION
Infections with these bacteria are often easily treated with
Oral Rehydration Solutions (ORS) and zinc as recommended
by WHO; however, some patients require antimicrobial therapy
in cases of bloody, severe, or persistent diarrhea (World Health
Organization, 2005). With increasing reports of high antibiotic
resistance among enterobacteria in Ghana, the treatment of
diarrhea caused by bacteria will be a challenge (Kunadu et al.,
2018; Obeng-Nkrumah et al., 2019). Reports of over 40% of
non-bacterial diarrhea in children being treated with antibiotics,
easy accessibility to antibiotics through unapproved means in
Ghana, and wrongful prescription of drugs are of grave concern
(Arhinful, 2009; Ahiabu et al., 2016). There are some studies
implicating bacteria in diarrhea cases in Ghana (Akuffo et al.,
2017; Mizutani et al., 2021), with a prevalence of rate of 3%
and high resistance to commonly abused drugs such as tetracycline
(Newman et al., 2011; Akuffo et al., 2017). This study aimed
to isolate bacterial organisms associated with diarrhea in patients
reporting to five health facilities in Ga West, Accra-Ghana,
and determine the antimicrobial susceptibility profile of
the isolates.
Diarrhea disease, although preventable and highly treatable is
the second leading cause of death among children under the
age of five globally, killing about 525,000 children annually
(World Health Organization, 2017). Diarrhea as defined by
WHO is the excessive and frequent evacuation of watery stools
usually indicating gastrointestinal disease or disorder of 3–7 days
duration (World Health Organization, 2017). The etiology of
diarrheal diseases mainly by a wide variety of viral, bacterial,
and parasitic pathogens is variable depending on a range of
conditions including but not limited to geographic and climate
conditions, host factors, and socioeconomic situations (Hodges
and Gill, 2010). Viral pathogens such as norovirus and rotavirus
infection are known to be a leading cause of diarrhea among
children under 2 years with the latter causing the highest fatality
among children (Tate et al., 2016). Parasites such as Entamoeba
histolytica, Giardia lamblia, and Cryptosporidium parvum have
also been recorded to cause morbid diarrhea episodes (Nkrumah
and Nguah, 2011; Gilchrist et al., 2016; Yang et al., 2021).
Among the bacterial causes, Escherichia coli is the most
common pathogen for childhood diarrhea in developing countries
and an emerging antimicrobial-resistant entero-pathogen in
developed countries (Zhou et al., 2018). Bacteria pathogens
causing diarrhea-associated diseases have however been somewhat
limited to Vibrio cholerae with some strains such as Ogawa
capable of causing epidemics when not well managed (Danso
et al., 2020). In Sub-Saharan Africa, diarrhea is known to
cause high fatality among children in rural and low-income
communities as compared to the Americas and Europe. This
is mainly because of unsanitary conditions such as defecation
into rivers and streams which double as drinking water for
livestock and humans, lack of potable drinking water, and
improper handling of household food can lead to increased
diarrhea cases (Larbi et al., 2021; Takyi et al., 2021).
In Ghana, cholera outbreaks and epidemics were recorded
in 1970, 2012, 2014, and 2015. The 2014–2015 epidemic affected
all 10 regions of the country accounting for a total of 28,922
cases including 243 deaths (Government of Ghana, 2015; Noora
et al., 2017) with observed clustering of isolates in some areas
of southern Ghana (Danso et al., 2020). However, it has been
established that diarrhea can be caused by different types of
bacteria other than V. cholerae including Campylobacter spp.,
Salmonella spp., Shigella spp., and pathogenic Escherichia coli
O15:H7 (although unresolved), and can be equally fatal when
left untreated (William et al., 2020; Wang et al., 2021).
Frontiers in Microbiology | www.frontiersin.org
MATERIALS AND METHODS
Ethical Considerations
This cross-sectional surveillance study conducted from August
2017 to May 2021 was approved by the Institutional Review
Board (IRB) of Noguchi Memorial Institute for Medical Research
(NMIMR; approval number: 096/16-1; dated May 3, 2017).
It was exempted from additional approval by the Ghana Health
Service Ethics Committee which considered the procedures
as compliant with routine service for patients care and
surveillance.
Study Area
The study was conducted in the Ga West Municipality which
lies between 5°35′North, 5°29′North, and longitude 0°10′West
and 0°24′West. It occupies a total surface area of 299.578
square kilometers with about 412 communities. Five health
facilities including a private facility within the municipality
were chosen as surveillance sites (Figure 1). The main occupation
or industry of inhabitants is trading and sales work of which
females dominate. Public toilets and pit latrines are the main
toilet facilities in the Municipality (Ghana Statistical
Service, 2013).
2
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
FIGURE 1 | A map showing the geographical locations of the participating health facilities.
Participants’ Data and Sample Collection
Individuals passing watery or loose stools three or more times
within 24 h with/without mucus and or blood, vomiting, fever,
and abdominal pain were eligible for this study.
Samples were taken between August 2017 and May 2021.
Before stool sample collection into a container, patients’ clinical
and demographic data including age, gender, height, weight,
food, and water taken 3 days before the onset of diarrhea,
temperature, number of stools per day, antibiotics taken, places
visited among others were recorded using a structured
questionnaire.
All collected stool samples were screened for V. cholerae
using a rapid diagnostic test kit (Abbott Bioline, United States)
at the various health facilities before transportation to the
NMIMR laboratory for analysis. With the aid of a swab stick,
a portion of the stool was inoculated into Cary Blair transport
medium on-site and transported to NMIMR in a cold chain
for culture and antimicrobial susceptibility testing.
(Park Scientific, United Kingdom) for isolation of Vibrio spp.,
Alkaline Peptone Water, APW (Himedia, India), an enrichment
medium for isolation of Vibrio spp. and Selenite Faecal Broth,
SFB (Himedia, India) an enrichment medium for isolation of
Salmonella and Shigella spp. and then incubated aerobically at
37°C for 18–24 h for isolation of enteric bacteria (Bolinches
et al., 1988; Akuffo et al., 2017). A loopful of SFB and APW
broth cultures were sub-cultured onto Salmonella Shigella Agar
(SS) and TCBS respectively and incubated as previously. Suspected
colonies of Salmonella spp., Shigella spp., E. coli, and Vibrio
spp. were purified and identified by colonial characteristics,
Gram staining reaction (Park Scientific, United Kingdom),
standard biochemical methods-Analytical Profile Index
(Biomerieux, United States), and Microscan Autoscan4 (Beckman
Coulter, United States), and Matrix-Assisted Laser Desorption/
Ionization-Time of Flight, MALDI-TOF (Bruker, United States).
Shigella, E. coli, Salmonella, and Vibrio cholerae isolates were
antigenically characterized using serological kits from Denka
Seiken, Japan (Nath et al., 2013; Pun, 2014).
Bacteria Isolation and Characterization
Antimicrobial Susceptibility Testing
Each sample was inoculated on four media: MacConkey agar
(ThermoScientific, United States) for isolation of non-lactose
fermenters and E. coli, Thiosulphate Citrate Bile Salt agar, TCBS
Only isolates that were regarded as diarrheagenic strains were
included in our analysis for antimicrobial susceptibility testing.
Susceptibility to antimicrobial agents was done by Kirby Bauer
Frontiers in Microbiology | www.frontiersin.org
3
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
disk diffusion technique per Clinical and Laboratory Standard
Institute (CLSI) guidelines (CLSI, 2020). Isolates were tested
against ceftriaxone (30 μg), norfloxacin (5 μg), cefotaxime (30 μg),
amikacin (30 μg), gentamycin (30 μg), clotrimazole (50 μg),
nalidixic acid (30 μg), tetracycline (30 μg), ceftazidime (30 μg),
ciprofloxacin (5 μg), nitrofurantoin (300 μg), and cefazolin (30 μg;
BD BBL, United Kingdom). Escherichia coli ATTC 25922
reference strain was used as a control. MicroScan autoScan4
MIC panels-Gram-Negative combo type 66 and Gram-Positive
PB 44 (Beckman Coulter, United States) were also used to
determine the susceptibility profiles of some isolates. Zones
of Inhibition were measured on Mueller Hinton Agar plates
in Kirby Bauer method and MIC used in MicroScan autoscan4.
Resistance, intermediate susceptibility, and susceptibility were
defined according to the CLSI breakpoints (CLSI, 2020).
participants was 39.8°C and the lowest 30.1°C with a mean
temperature of 36.3°C. Symptoms such as fever (347, 36.8%)
vomiting (374, 47.2%), weakness (529, 66.8%), and muscle cramps
(297, 37.5%) were recorded among the patients (Table 1).
Distribution of Diarrheic Bacteria
Characterized
Bacterial isolates were obtained from 772/792 stool samples
collected; 21.6% (167/772) were diarrheagenic bacteria including
E. coli (from bloody stool as well as stool from children under
five), and three other bacteria genera namely: Vibrio, Salmonella,
and Shigella. There were 5.2% (40/772) Salmonella spp., 2.2%
(17/772) Shigella spp., 3.6% (28/772) Vibrio sp., and 10.6%
(82/772) E. coli, from bloody or infant stool (infant <5 years;
Table 2). There was however no significant difference (p > 0.05)
between the different bacteria etiology of diarrhea isolated from
all five health facilities (Table 3).
Other species of bacteria including but not limited to Klebsiella
(N = 50), Raoultella (N = 16), and Enterobacter (N = 6) were
isolated but not further analyzed for this work.
The Vibrio spp. (N = 28) were further characterized into six
species namely: Vibrio parahaemolyticus (13/28, 46.4%),
V. cholerae (9/28, 32.1%), Vibrio fluvialis (2/28, 7.1%), Vibrio
sp. group (2/28, 7.1%), Vibrio albensis (1/28, 3.6%), and Vibrio
alginolyticus (1/28, 3.6%). Sixteen out of the 17 (94.1%) Shigella
species were identified as Shigella flexneri (11, 64.7%) Shigella
dysenteriae (2, 11.8%), Shigella sonnei (2,11.8%), and Shigella
boydii (1, 5.9%).
Upon serological analysis, E. coli strains were grouped, with
the most prominent being serogroups O8 (4, 4.9%) and O153
(3, 3.7%), known to be enterotoxigenic (Escribano et al., 1987;
Table 2). Among Salmonella isolates, serogroups O13 (15.0%)
and O4 (17.5%) were the most dominant. More than one
diarrhoeagenic bacteria were isolated from some of the patients;
Salmonella and E. coli (4/792, 0.5%), Shigella, and E. coli (3/792,
0.4%) were isolated from mainly bloody stools.
ESBL Characterization/Multidrug
Resistance
All extended spectrum-beta-lactamase (ESBLs) in this study
were identified using a Gram-negative Combo type 66 panel
on a MicroScan autoScan-4. This panel detects MIC of drugs
and also virulent markers such as ESBL, and carbapenems.
Multidrug resistance was defined as isolates being resistant to
more than three antibiotic drug classes (Magiorakos et al., 2012).
Data Management and Analysis
Participants’ clinical, demographic, and laboratory data were
entered into Epi Info version 2.0 Software (Centers for Disease
Control and Prevention, CDC, Atlanta, GA, United States) and
analyzed using Stata v14.2 (Stata Corporation, College Station,
TX, United States). Descriptive statistics were carried out for
both categorical and numerical variables. Cross-tabulations were
further employed to explore the relationship between the
different outcomes and selected variables using Chi-square and
student t-test where applicable. Where appropriate, the Fisher’s
exact or the chi-square tests were used to assess statistical
significance. A p-value of less than 0.05 at a 95% confidence
level was considered significant. The ArcMap tool employed
in ArcGIS (Economic and Social Research Institute, version
10.1; ESRI, 2010) was used for constructing maps.
Antimicrobial Susceptibility Profiles of
Isolates
Antimicrobial susceptibility testing (AST) was done for 24 out
of the 28 isolated Vibrio spp. (Figure 3) of which all were
susceptible to gentamicin, an aminoglycoside but moderately
susceptible to amikacin (14/24, 58.3%). The Vibrio isolates showed
resistance to cefazolin (18/24, 75%) among which all 13
V. parahaemolyticus isolates were resistant to cefazolin. Our Vibrio
isolates showed 25% (6/24) resistance to ciprofloxacin, used to
treat non-cholera Vibrio infections. Isolates tested against cefotaxime
(21/24, 87.5%) and ceftriaxone (20/24, 83.3%) also used in Vibrio
infection treatment were highly susceptible. A total of four multidrug resistant Vibrio strains were identified with resistances to
fluoroquinolones, cephalosporins, and aminoglycosides.
Out of the 40 Salmonella isolates, AST was done for 34
isolates (Figure 3). We detected high resistance of Salmonella
isolates to tetracycline (12/34, 35.3%) but relatively low resistance
to ciprofloxacin (3/34, 8.8%) and ceftriaxone (2/34, 5.9%). The
RESULTS
Demographic and Clinical Characterization
of Cases
Seven hundred and ninety-two diarrheic stool samples were
collected from the health facilities; 297 (37.5%) males and 495
(62.5%) females. The ages of participants ranged between
5 months and 88 years with the majority (589/792, 74.3%) being
adults (>17 years) and a mean age of 29.3 years (Figure 2).
Clinical records indicated that 124 (15.7%) patients had taken
antibiotics, 85 (10.7%) antimalarials, 40 (5.0%) anthelminthic,
37 (4.7%) both antibiotics and antimalarials, 17 (2.1%) all three
drugs, and 497 (62.8%) had not taken any drug before visiting
the health facilities. The highest temperature recorded among
Frontiers in Microbiology | www.frontiersin.org
4
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
FIGURE 2 | Age distribution of participants.
Salmonella isolates showed total susceptibility when tested
against gentamycin and norfloxacin with no multi-drug resistant
Salmonella strains however found.
All 17 Shigella isolates were tested against our selected
antimicrobials (Figure 3) and were found to be resistant to
tetracycline. Three multidrug-resistant Shigella isolates were
identified. One (5.9%) isolate was resistant to three drugs
(norfloxacin, ciprofloxacin, and tetracycline), and two (11.8%)
were resistant to both norfloxacin and ciprofloxacin.
Antimicrobial susceptibility testing was done on 72/82 E. coli
isolates and when tested against all our selected antimicrobials,
at least one antimicrobial resistance for each isolate was observed
(Figure 3). Escherichia coli isolates showed the highest resistance
to tetracycline (57/72, 79.1%) and cefazolin (43/72, 58.3%).
The isolates were highly susceptible to aminoglycosides, amikacin
(57/72, 79.2%), and gentamicin (66/72, 91.7%), and nitrofurantoin
(60/72, 83.3%) which is prescribed for treating E. coli infections.
We detected high resistance to one fluoroquinolone, ciprofloxacin
(22/72, 30.6%) with two extended-spectrum beta-lactamasesproducing E. coli identified.
TABLE 1 | Symptoms presented by participants.
Vomiting
Present
Absent
Not specified
Muscular cramps
Present
Absent
Not specified
Weakness
Present
Absent
Not specified
Fever
High grade
Low grade
Absent
Not specified
374 (47.2)
388 (49.0)
30 (3.8)
Frequency
297 (37.5)
408 (51.5)
87 (11.0)
Frequency
529 (66.8)
231 (29.2)
32 (4.0)
Frequency
110 (13.9)
237 (23.9)
350 (44.2)
95 (12.0)
important findings. The diversity and frequency of bacteria
isolated from this study concur with similar reports from China,
Kenya, and India (Mbuthia et al., 2018; William et al., 2020;
Wang et al., 2021). The prevalence of Shigella, Salmonella,
Vibrio, and diarrheagenic E. coli is consistent with previous
studies in Ghana and other African countries (Akuffo et al.,
2017; Kalule et al., 2019). However, reports from Lompo et al.
DISCUSSION
Our routine surveillance study of diarrhea from Ga West
Municipality in Ghana from 2017 to 2021 has revealed several
Frontiers in Microbiology | www.frontiersin.org
Frequency N (%)
5
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
TABLE 3 | Frequency of bacteria isolated according to health facilities.
TABLE 2 | Bacteria isolates and serotypes.
Variable
Vibrio species
Vibrio parahaemolyticus
Vibrio cholerae
Vibrio fluvialis
Vibrio sp. group
Vibrio albensis
Vibrio alginolyticus
Escherichia coli serogroups
O127a
O8
O159
O153
O25
O142
O11
O169
O18
O44
O164
O6
O26
O86a
O20
Non-reactive
Shigella serogroups
Shigella flexneri type I
Shigella flexneri type II
Shigella flexneri type III
Shigella dysenteriae type II
Shigella dysenteriae type IV
Shigella boydii type 12
Shigella sonnei Phase I
Non-reactive
Salmonella serogroups
O3, 10
O35
O4
O7
O8
O9
O13
Non-reactive
Frequency of organism
Number (%)
Health facility
N = 28
13 (46.4)
9 (32.1)
2 (7.1)
2 (7.1)
1 (3.6)
1 (3.6)
N = 82
1 (1.2)
4 (4.9)
1 (1.2)
3 (3.6)
1 (1.2)
1 (1.2)
2 (2.4)
1 (1.2)
2 (2.4)
1 (1.2)
1 (1.2)
2 (2.4)
1 (1.2)
2 (2.4)
1 (1.2)
58 (70.7)
N = 17
2 (11.8)
7 (5.9)
2 (11.8)
1 (5.9)
1 (5.9)
1 (5.9)
2 (11.8)
1 (5.9)
N = 40
3 (7.5)
1 (2.5)
7 (17.5)
1 (2.5)
1 (2.5)
5 (12.5)
6 (15.0)
16 (40.0)
Ga West
Municipal
Hospital (N = 78)
Mayera Health
Center (N = 31)
Oduman Health
Center (N = 34)
Kotoku Health
Center (N = 17)
St. John’s
Hospital (N = 7)
Total (N = 167)
Salmonella
spp. (%)
Shigella
spp. (%)
Vibrio
spp. (%)
35 (44.9)
23 (29.5)
6 (7.7)
14 (17.9)
19 (61.3)
7 (22.6)
3 (9.7)
2 (6.4)
18 (52.9)
4 (11.8)
3 (8.8)
9 (26.5)
8 (47.1)
4 (23.5)
3 (17.6)
2 (11.8)
3 (42.8)
2 (28.6)
1 (14.3)
1 (14.3)
82
40
17
28
p-Value
0.473
ciprofloxacin, norfloxacin, and nalidixic acid used in treating
Vibrio and Shigella is of critical concern.
We observed an emerging resistance of Vibrio isolates
to ciprofloxacin, a potent cholera medication with 23.1%
resistance and 30.8% intermediate resistance consistent with
reports in Nigeria, Cameroon, and China (Quilici et al.,
2010; de Melo et al., 2011). Our study also identified eight
cases of V. cholerae which is a public health emergency
when not properly managed. In our study, we isolated 13
V. parahaemolyticus from diarrhea stools. Two patients infected
with V. parahaemolyticus presented bloody stool samples
with 76.9% (10/13) of V. parahaemolyticus infected patients
on admission. Bloody stool samples can be a result of
V. parahaemolyticus damaging the epithelial layer of the
small intestines through the creation of cavities (Wang et al.,
2022). Classical V. parahaemolyticus infection symptoms such
as high fever (53.8%), vomiting (53.8%), muscular cramps
(46.2%), and general weakness (76.9%) were observed in
all infected patients consistent with reports by Jung (2018).
Vibrio parahaemolyticus is highly prevalent in marine coastal
areas and associated with seafood and endemic in SouthEastern Asia countries including Taiwan, Japan, and China
causing many foodborne illnesses (Junhe et al., 2018; Zhao
et al., 2020). These V. parahaemolyticus were isolated from
stools in an area highly deprived of potable water hence
depending on the river Densu for water. Residents living
along the coast defecate, feed animals, wash and drink from
this river, which is of huge public health concern. Vibrio
parahaemolyticus is known to cause acute gastroenteritis
characterized by diarrhea. Although self-limiting, strains of
V. parahaemolyticus are virulent enough to cause outbreaks
and can be fatal (Jung, 2018). With recent reports of
antimicrobial-resistant strains (Tan et al., 2020; Jingjit et al.,
2021), there is an urgent need to tackle it.
We found Shigella isolates to be totally (100%) resistant
to tetracycline. This might be a result of the extensive use
of tetracycline in Ghana over the years with several reports
on antimicrobial resistance to these drugs (Newman et al.,
2011; Yevutsey et al., 2017). There might also be some
(2021) did not isolate Salmonella from diarrheic stool samples.
In our study, we isolated diarrheagenic bacteria from 21%
(167/779) of stool samples received which is markedly high
compared to previous studies in Ghana and elsewhere (4%;
Akuffo et al., 2017; William et al., 2020). This high prevalence
may be due to our sampling site, Ga West an area without
potable drinking water and thus unsanitary living conditions.
As previously reported, diarrheagenic bacteria have been isolated
from street food samples in Ghana, which may result in more
bacteria diarrhea cases in areas with unsanitary living conditions
(Mensah et al., 2002). In a country where most diarrheal cases
are thought to only be caused by V. cholerae, this revelation
is very important. The frequency of Shigella, Salmonella, Vibrio,
and enterotoxigenic E. coli emphasizes the need to scale up
laboratory-based surveillance and appropriate determination of
disease etiology for effective treatment of diarrheal diseases.
The observable emerging resistance to potent drugs such as
Frontiers in Microbiology | www.frontiersin.org
E. coli (%)
6
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
A
B
C
D
FIGURE 3 | Resistance patterns of the various bacterial strains to 12 antibiotics. (A) Escherichia coli showing high resistance to tetracycline, cephalothin, and
cefazolin. (B) Shigella isolates were totally resistant to tetracycline with no resistance to ceftazidime. (C) Vibrio isolates showed high resistance to cefazolin and
complete susceptibility to gentamycin. (D) All Salmonella isolates were susceptible to norfloxacin, cefotaxime, and gentamycin with 35% of isolates resistant to
tetracycline. CTR, ceftriaxone; NOR, norfloxacin; AMK, amikacin; CTX, cefotaxime; GEN, gentamycin; CTL, cephalothin; NAL, nalidixic acid; TET, tetracycline; CAZ,
ceftazidime; CPR, ciprofloxacin; NIT, nitrofurantoin; and CZL, cefazolin.
in Shigella dysentery infections in adults (Basnet et al., 2021).
Observations of high susceptibility of Shigella sp. to ceftriaxone
and high resistance to nalidixic acid, tetracycline, and amikacin
is consistent with Pourakbari et al. (2010) and Basnet et al.
(2021). Parenteral ceftriaxone is highly effective and
recommended in the treatment of hospitalized children with
contribution from the irresponsible use in the animal farming
industry as a result of easy access to the drug from pharmacies
(Wilcox, 2009; Andoh et al., 2016). The Shigella spp. were
additionally resistant to amikacin (4/17, 23.5%), ciprofloxacin
(4/17, 23.5%), nalidixic acid (3/17, 17.6%), and norfloxacin
(1/17, 5.9%) with the latter two formerly potent drugs used
Frontiers in Microbiology | www.frontiersin.org
7
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
severe shigellosis (Ashkenazi et al., 2003) so the emergence
of high resistance to this drug is of great concern.
Serological analysis of isolated E. coli yielded a high prevalence
of serotypes O8 (4.9%) and O153 (3.7%). The serotype O153,
an enterotoxigenic Escherichia coli (ETEC) has been reported
to harbor a large number of virulent genes capable of causing
mild to severe infections (Díaz-Jiménez et al., 2020). There
are reports of this E. coli strain being isolated from patients
during an outbreak which may be indicative of its ability to
cause an epidemic (Kennedy et al., 2018). Extended-spectrum
beta-lactamase (ESBL)-producing E. coli were also detected in
our study buttressing the high level of resistance occurring in
our communities. The transmission and spread of these virulent
E. coli strains in local communities can be of great danger to
public health.
The identification of multi-drug resistant Vibrio species
in this study continues to show the rising incidence of
antimicrobial resistance in the communities. A major problem
in Ghanaian communities is the indiscriminate use of
antibiotics in animal husbandry and farming sectors as
growth supplements for the prevention of infection and
subsequently, increasing yield. This practice pre-exposes
drugs to these pathogens hence hastening the rate at which
antimicrobial resistance develops (Wilcox, 2009; Andoh et al.,
2016). Multi-drug resistant Vibrio isolates may increase
disease severity, morbidity, and mortality and increase
constraints on our public health system.
Good hygiene practices will curb the spread of these
pathogens since most of these infections are spread through
person-to-person contact. The sentinel site chosen in this
surveillance study is a community where inhabitants have
limited access to pipe-borne water. Residents in some of the
communities depend on streams, boreholes, and even rainwater
as sources of water for drinking and household chores.
Improper disposal of human waste is also another problem
in the community. Open defecation into water bodies and
bushes coupled with potable water scarcity could account for
the high diarrhea cases (Larbi et al., 2021). Practices such
as handwashing, proper cooking of food, as well as proper
disposal of human and household waste, are known to curb
the spread of bacterial pathogens causing diarrhea. Communities
must be engaged regularly in the implementation of water,
sanitation, and hygiene (WASH) practices. We identified a
couple of limitations in the study. Molecular methods such
as PCR would have been more sensitive and given a better
understanding of the diarrheagenic E. coli and ESBLs isolated
as compared to serological analysis only.
We did not have data on the total number of individuals
presenting diarrhea to the health facilities as samples taken
were from only patients who agreed to be in this study.
better treatment outcomes. Resistance observed in all isolates
is of public health concern since drugs used in the treatment
of Shigellosis, Salmonellosis, and other diarrhea diseases
showed marked resistance. This can lead to pressure on our
public health system should drugs not work against intended
pathogens. A diarrheagenic prevalence rate of 21% further
stresses the need for differential diagnosis in diarrhea cases
for better treatment outcomes. The presence of multi-drug
resistant Vibrio isolates and an increase in Vibrio
parahaemolyticus which is highly associated with food poisoning
as well as the high resistant rates of Shigella isolates and
ESBLs detected is forewarning and raises the need for the
implementation of preventive strategies to minimize
transmission. Routine antimicrobial susceptibility testing,
effective monitoring, and nationwide surveillance of AMR
pathogens should be implemented to curb the increase of
antimicrobial resistance in Ghana.
CONCLUSION
FUNDING
This study has shown the diverse bacteria etiology (Salmonella,
Shigella, Vibrio, and some E. coli) implicated in diarrhea
disease and the need for proper differential diagnosis for
This study was supported by AMED-JICA [the Science and
Technology Research Partnership for Sustainable Development
(SATREPS); 19jm0110012].
Frontiers in Microbiology | www.frontiersin.org
DATA AVAILABILITY STATEMENT
The original contributions presented in the study are included
in the article/supplementary material, further inquiries can
be directed to the corresponding author.
ETHICS STATEMENT
The studies involving human participants were reviewed and
approved by the Institutional Review Board (IRB) of Noguchi
Memorial Institute for Medical Research (NMIMR; approval
number: 096/16-1; dated on May 3, 2017). It was exempted
from additional approval by the Ghana Health Service Ethics
Committee which considered the procedures as compliant with
routine service for patients care and surveillance. Written
informed consent to participate in this study was provided by
the participants’ legal guardian/next of kin.
AUTHOR CONTRIBUTIONS
DY-M, KK, HK, KT, FA-B, AA-P, and GM: conceptualization,
fund acquisition, and writing—review and editing. TA, DA,
and AM: investigation. TA, DY-M, and PA: writing—original
draft and formal analysis. DY-M, AA-P, GM, TA, DA, and
AM: methodology. DY-M: resources, project administration,
and supervision. DO, NG, TA, DA, KI, TMa, and TMi:
writing—review and editing. AA: project administration. All
authors contributed to the article and approved the submitted
version.
8
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
ACKNOWLEDGMENTS
in particular, Emmanuel Danso the project driver for his selflessness
in his duties. We are sincerely grateful to all staff at the National
Public Health reference laboratory and all participants of this
study for their time and cooperation during this study.
The authors express our greatest gratitude to all laboratory staff
at the various health facilities where samples were collected and
Jingjit, N., Preeprem, S., Surachat, K., and Mittraparp-Arthorn, P. (2021).
Characterization and analysis of clustered regularly interspaced short
palindromic repeats (CRISPRs) in pandemic and non-pandemic Vibrio
parahaemolyticus isolates from seafood sources. Microorganisms 9:1220. doi:
10.3390/microorganisms9061220
Jung, S. W. (2018). A foodborne outbreak of gastroenteritis caused by Vibrio
parahaemolyticus associated with cross-contamination from squid in Korea.
Epidemiol. Health 40:e2018056. doi: 10.4178/epih.e2018056
Junhe, L., Baisheng, L., Taohua, L., Zhaowen, P., Miaolin, H., and Jingwen, Z.
(2018). Etiological characteristics of Vibrio parahaemolyticus strains isolated
from a food poisoning event in Jiangmen, Guangdong. Dis. Surveill. 33,
387–390. doi: 10.3784/j.issn.1003-9961.2018.05.009
Kalule, J. B., Smith, A. M., Vulindhlu, M., Tau, N. P., Nicol, M. P., Keddy, K. H.,
et al. (2019). Prevalence and antibiotic susceptibility patterns of enteric bacterial
pathogens in human and non-human sources in an urban informal settlement
in cape town, South Africa. BMC Microbiol. 19, 1–11. doi: 10.1186/s12866-019-1620-6
Kennedy, C., Walsh, C., Karczmarczyk, M., O’Brien, S., Akasheh, N., Quirke, M.,
et al. (2018). Multi-drug resistant Escherichia coli in diarrhoeagenic foals:
pulsotyping, phylotyping, serotyping, antibiotic resistance and virulence
profiling. Vet. Microbiol. 223, 144–152. doi: 10.1016/j.vetmic.2018.08.009
Kunadu, A. P. H., Holmes, M., Miller, E. L., and Grant, A. J. (2018). Microbiological
quality and antimicrobial resistance characterization of Salmonella spp. in
fresh milk value chains in Ghana. Int. J. Food Microbiol. 277, 41–49. doi:
10.1016/j.ijfoodmicro.2018.04.025
Larbi, R. T., Atiglo, D. Y., Peterson, M. B., Biney, A. A., Dodoo, N. D., and
Dodoo, F. N. A. (2021). Household food sources and diarrhoea incidence
in poor urban communities, Accra Ghana. PLoS One 16:e0245466. doi:
10.1371/journal.pone.0245466
Lompo, P., Tahita, M. C., Sorgho, H., Kaboré, W., Kazienga, A., Nana, A. C.
B., et al. (2021). Pathogens associated with acute diarrhea, and comorbidity
with malaria among children under five years old in rural Burkina Faso.
Pan. Afr. Med. J. 38:259. doi: 10.11604/pamj.2021.38.259.15864
Magiorakos, A. P., Srinivasan, A., Carey, R. B., Carmeli, Y., Falagas, M., Giske, C.,
et al. (2012). Multidrug-resistant, extensively drug-resistant and pandrugresistant bacteria: an international expert proposal for interim standard
definitions for acquired resistance. Clin. Microbiol. Infect. 18, 268–281. doi:
10.1111/j.1469-0691.2011.03570.x
Mbuthia, O. W., Mathenge, S. G., Oyaro, M. O., and Ng’ayo, M. O. (2018).
Etiology and pathogenicity of bacterial isolates: a cross sectional study among
diarrheal children below five years in central regions of Kenya. Pan. Afr.
Med. J. 31:88. doi: 10.11604/pamj.2018.31.88.15644
Mensah, P., Yeboah-Manu, D., Owusu-Darko, K., and Ablordey, A. (2002).
Street foods in Accra, Ghana: how safe are they? Bull. World Health Organ.
80, 546–554.
Mizutani, T., Aboagye, S. Y., Ishizaka, A., Afum, T., Mensah, G. I., Asante-Poku, A.,
et al. (2021). Gut microbiota signature of pathogen-dependent dysbiosis in
viral gastroenteritis. Sci. Rep. 11, 1–11. doi: 10.1038/s41598-021-93345-y
Nath, R., Saikia, L., Choudhury, G., and Sharma, D. (2013). Drug resistant
Shigella flexneri in & around Dibrugarh, north-East India. Indian J. Med.
Res. 137, 183–186.
Newman, M. J., Frimpong, E., Donkor, E. S., Opintan, J. A., and Asamoah-Adu, A.
(2011). Resistance to antimicrobial drugs in Ghana. Infect. Drug Resist. 4,
215–220. doi: 10.2147/IDR.S21769
Nkrumah, B., and Nguah, S. B. (2011). Giardia lamblia: a major parasitic cause
of childhood diarrhoea in patients attending a district hospital in Ghana.
Parasit. Vectors 4, 1–7. doi: 10.1186/1756-3305-4-163
Noora, C. L., Issah, K., Kenu, E., Bachan, E. G., Nuoh, R. D., Nyarko, K. M.,
et al. (2017). Large cholera outbreak in Brong Ahafo region, Ghana. BMC
Res. Notes 10:389. doi: 10.1186/s13104-017-2728-0
Obeng-Nkrumah, N., Labi, A. K., Blankson, H., Awuah-Mensah, G.,
Oduro-Mensah, D., Anum, J., et al. (2019). Household cockroaches carry
CTX-M-15-, OXA-48-and NDM-1-producing enterobacteria, and share beta-
REFERENCES
Ahiabu, M. A., Tersbøl, B. P., Biritwum, R., Bygbjerg, I. C., and Magnussen, P.
(2016). A retrospective audit of antibiotic prescriptions in primary healthcare facilities in eastern region, Ghana. Health Policy Plan. 31, 250–258.
doi: 10.1093/heapol/czv048
Akuffo, R., Armah, G., Clemens, M., Kronmann, K., Jones, A., Agbenohevi, P.,
et al. (2017). Prevalence of enteric infections among hospitalized patients
in two referral hospitals in Ghana. BMC Res. Notes 10, 1–7. doi: 10.1186/
s13104-017-2621-x
Andoh, L., Dalsgaard, A., Obiri-Danso, K., Newman, M., Barco, L., and Olsen, J.
(2016). Prevalence and antimicrobial resistance of Salmonella serovars isolated
from poultry in Ghana. Epidemiol. Infect. 144, 3288–3299. doi: 10.1017/
S0950268816001126
Arhinful, D.K. (2009). WHO pharmaceutical situation assessment: level II-health
facilities survey in Ghana. Ghana: Ministry of Health.
Ashkenazi, S., Levy, I., Kazaronovski, V., and Samra, Z. (2003). Growing
antimicrobial resistance of Shigella isolates. J. Antimicrob. Chemother. 51,
427–429. doi: 10.1093/jac/dkg080
Basnet, B., Niroula, D., Acharya, J., and Basnyat, S. (2021). Antibiotic
susceptibility pattern of Shigella spp. isolated from patients suspected of
acute gastroenteritis. J. Instr. Sci. Technol. 26, 1–7. doi: 10.3126/jist.v26i2.41261
Bolinches, J., Romalde, J. L., and Toranzo, A. E. (1988). Evaluation of selective
media for isolation and enumeration of vibrios from estuarine waters.
J. Microbiol. Methods 8, 151–160. doi: 10.1016/0167-7012(88)90016-4
CLSI (2020). Performance Standards for Antimicrobial Susceptibility Testing.
30th ed. CLSI supplement M100. Wayne, PA: Clinical and Laboratory
Standards Institute. [Internet]. Available at: https://clsi.org/media/3481/
m100ed30_sample.pdf (Accessed April 21, 2022).
Danso, E. K., Asare, P., Otchere, I. D., Akyeh, L. M., Asante-Poku, A.,
Aboagye, S. Y., et al. (2020). A molecular and epidemiological study of
Vibrio cholerae isolates from cholera outbreaks in southern Ghana. PLoS
One 15:e0236016. doi: 10.1371/journal.pone.0236016
de Melo, L. M. R., Almeida, D., Hofer, E., dos Reis, C. M. F., Theophilo, G. N.
D., Santos, A. F., et al. (2011). Antibiotic resistance of Vibrio parahaemolyticus
isolated from pond-reared Litopenaeus vannamei marketed in Natal, Brazil.
Braz. J. Microbiol. 42, 1463–1469. doi: 10.1590/S1517-83822011000400032
Díaz-Jiménez, D., García-Meniño, I., Herrera, A., García, V., López-Beceiro, A. M.,
Alonso, M. P., et al. (2020). Genomic characterization of Escherichia coli
isolates belonging to a new hybrid aEPEC/ExPEC pathotype O153: H10A-ST10 eae-beta1 occurred in meat, poultry, wildlife and human diarrheagenic
samples. Antibiotics 9:192. doi: 10.3390/antibiotics9040192
Escribano, A., Ørskov, I., Ørskov, F., and Borras, R. (1987). Enterotoxigenic
Escherichia coli O153: H45 from an outbreak of diarrhoea in Spain. Med.
Microbiol. Immunol. 176, 241–244. doi: 10.1007/BF00190530
ESRI (2010). Introducing ArcGIS 10.1. Available at: https://www.esri.com/news/
arcnews/spring12articles/introducing-arcgis-101.html (Accessed January 11, 2022).
Ghana Statistical Service (2013). 2010 Population and Housing Census. Regional
Analytical Report. Greater Accra Region. [Internet]. Available at: https://
www2.statsghana.gov.gh/docfiles/2010phc/2010_PHC_Regional_Analytical_
Reports_Greater_Accra_Region.pdf (Accessed June 6, 2021).
Gilchrist, C. A., Petri, S. E., Schneider, B. N., Reichman, D. J., Jiang, N.,
Begum, S., et al. (2016). Role of the gut microbiota of children in diarrhea
due to the protozoan parasite Entamoeba histolytica. J. Infect. Dis. 213,
1579–1585. doi: 10.1093/infdis/jiv772
Government of Ghana (2015). Ghana weekly epidemiological bulletin [Internet].
Available at: http://www.ghanahealthservice.org/downloads/Weekly_Epid_
Bulletin_Week_1_2015.pdf (Accessed May 16, 2021).
Hodges, K., and Gill, R. (2010). Infectious diarrhea: cellular and molecular
mechanisms. Gut Microbes 1, 4–21. doi: 10.4161/gmic.1.1.11036
Frontiers in Microbiology | www.frontiersin.org
9
May 2022 | Volume 13 | Article 894319
Afum et al.
Antimicrobial Resistance in Entero-Pathogens
lactam resistance determinants with humans. BMC Microbiol. 19, 1–11. doi:
10.1186/s12866-019-1629-x
Pourakbari, B., Mamishi, S., Mashoori, N., Mahboobi, N., Ashtiani, M. H.,
Afsharpaiman, S., et al. (2010). Frequency and antimicrobial susceptibility
of Shigella species isolated in children medical center hospital, Tehran, Iran,
2001-2006. Braz. J. Infect. Dis. 14, 153–157. doi: 10.1016/S1413-8670(10)70029-5
Pun, S. B. (2014). The first appearance of classical-like phenotype Vibrio cholerae
in Nepal. North Am. J. Med. Sci. 6, 183–184. doi: 10.4103/1947-2714.131248
Quilici, M. L., Massenet, D., Gake, B., Bwalki, B., and Olson, D. M. (2010).
Vibrio cholerae O1 variant with reduced susceptibility to ciprofloxacin,
Western Africa. Emerg. Infect. Dis. 16, 1804–1805. doi: 10.3201/eid1611.100568
Takyi, S. A., Amponsah, O., Yeboah, A. S., and Mantey, E. (2021). Locational
analysis of slums and the effects of slum dweller’s activities on the social,
economic and ecological facets of the city: insights from Kumasi in Ghana.
GeoJournal 86, 2467–2481. doi: 10.1007/s10708-020-10196-2
Tan, C. W., Rukayadi, Y., Hasan, H., Thung, T. Y., Lee, E., Rollon, W. D.,
et al. (2020). Prevalence and antibiotic resistance patterns of Vibrio
parahaemolyticus isolated from different types of seafood in Selangor, Malaysia.
Saudi J. Biol. Sci. 27, 1602–1608. doi: 10.1016/j.sjbs.2020.01.002
Tate, J. E., Burton, A. H., Boschi-Pinto, C., and Parashar, U. D.World Health
Organization–Coordinated Global Rotavirus Surveillance Network (2016). Global,
regional, and national estimates of rotavirus mortality in children< 5 years
of age, 2000–2013. Clin. Infect. Dis. 62, S96–S105. doi: 10.1093/cid/civ1013
Wang, J., Zhan, Y., Sun, H., Fu, X., Kong, Q., Zhu, C., et al. (2022). Regulation
of virulence factors expression during the intestinal colonization of Vibrio
parahaemolyticus. Foodborne Pathog. Dis. 19, 169–178. doi: 10.1089/fpd.2021.0057
Wang, L. P., Zhou, S. X., Wang, X., Lu, Q. B., Shi, L. S., Ren, X., et al. (2021).
Etiological, epidemiological, and clinical features of acute diarrhea in China.
Nat. Commun. 12, 1–12. doi: 10.1038/s41467-021-22551-z
Wilcox, M. H. (2009). The tide of antimicrobial resistance and selection. Int.
J. Antimicrob. Agents 34, S6–S10. doi: 10.1016/S0924-8579(09)70550-3
William, A., Satija, S., and Kaur, R. (2020). Bacterial etiology of diarrhoea in
a tertiary care hospital. Int. J. Recent Sci. Res. 11, 39022–39024. doi: 10.24327/
ijrsr.2020.1106.5426
World Health Organization (2005). The treatment of diarrhoea: a manual for
physicians and other senior health workers. World Health Organization.
Report No: 9241593180.
Frontiers in Microbiology | www.frontiersin.org
World Health Organization (2017). WHO Diarrhoeal Disease Key Facts [Internet].
Available at: https://www.who.int/news-room/fact-sheets/detail/diarrhoealdisease (Accessed January 30, 2021).
Yang, X., Guo, Y., Xiao, L., and Feng, Y. (2021). Molecular epidemiology of
human cryptosporidiosis in low-and middle-income countries. Clin. Microbiol.
Rev. 34, e00087–e00119. doi: 10.1128/CMR.00087-19
Yevutsey, S. K., Buabeng, K. O., Aikins, M., Anto, B. P., Biritwum, R. B.,
Frimodt-Møller, N., et al. (2017). Situational analysis of antibiotic use and
resistance in Ghana: policy and regulation. BMC Public Health 17, 1–7.
doi: 10.1186/s12889-017-4910-7
Zhao, S., Zhao, Q., Ye, H., Yang, G., Li, J., and Huo, X. (2020). Investigation
on a food poisoning caused by Vibrio parahaemolyticus and its etiology. J.
Public Health Prev. Med. 113–117.
Zhou, Y., Zhu, X., Hou, H., Lu, Y., Yu, J., Mao, L., et al. (2018). Characteristics
of diarrheagenic Escherichia coli among children under 5 years of age with
acute diarrhea: a hospital based study. BMC Infect. Dis. 18, 1–10. doi:
10.1186/s12879-017-2936-1
Conflict of Interest: The authors declare that the research was conducted in
the absence of any commercial or financial relationships that could be construed
as a potential conflict of interest.
Publisher’s Note: All claims expressed in this article are solely those of the
authors and do not necessarily represent those of their affiliated organizations,
or those of the publisher, the editors and the reviewers. Any product that may
be evaluated in this article, or claim that may be made by its manufacturer, is
not guaranteed or endorsed by the publisher.
Copyright © 2022 Afum, Asandem, Asare, Asante-Poku, Mensah, Musah, Opare,
Taniguchi, Guinko, Aphour, Arhin, Ishikawa, Matano, Mizutani, Asiedu-Bekoe,
Kiyono, Anang, Koram and Yeboah-Manu. This is an open-access article distributed
under the terms of the Creative Commons Attribution License (CC BY). The
use, distribution or reproduction in other forums is permitted, provided the
original author(s) and the copyright owner(s) are credited and that the original
publication in this journal is cited, in accordance with accepted academic
practice. No use, distribution or reproduction is permitted which does not comply
with these terms.
10
May 2022 | Volume 13 | Article 894319