Bacterial etiology of diarrhoeal diseases in children ...

original article Bacterial etiology of diarrhoeal diseases in children
under 5 years old in Ombadda Hospital-Sudan

Bacterial etiology of diarrhoeal diseases in children under
5 years old in Ombadda Hospital - Sudan

Mustafa Mohammed Osman, Abdullahi Nur Hassan, Mohamed A. Holie

Correspondence
Abdullahi N Hassan, Alzaiem Alazhari University / Faculty of Medicine
E-mail: [email protected]

Abstract

This study was conducted in Ombadda hospital in order to isolate and identify the bacterial aetiology
of diarrhoea in children under 5years of age and determine their antibiograms. Stool specimens were
collected from children seeking treatment at Ombadda and Omdurman paediatric hospitals from April
to September 2008. The stool specimens were cultured on conventional media, and the isolates were
identified by biochemical tests, and confirmed by serology. Enteropathogenic E.coli (EPEC) was the
predominant isolate (42.11%), followed by Salmonella paratyphi B (31.58%), Salmonella typhi (10.53%)
V. cholerae (10.53%) and Shigella flexneri (5.26%). The enteric bacterial pathogens were susceptible to
cefuroxime and ceftriaxone. V.cholerae was susceptible to amoxicillin.
This study showed high proportion of bacterial diarrhoea among children less than five years old. The
most common causative agent is EPEC which is not part of routine investigation of stool culture in all of
the laboratories in Sudan.
Key words: diarrhoeal diseases, diarrhoeal diseases in children, diarrhoeal in Sudan, EPEC infection,
infectious diarrhoea, diarrhaegenic E coli in Khartoum

Introduction disease are Salmonella species, Shigella species,
Infectious diarrhoea is a common illness that diarrhaegenic E coli, Vibrio cholera, Campylobacter
affects millions of children worldwide especially jejuni, Aeromonas species and Yersinia enterocolitica.
in developing countries(1-2). It is estimated that The prevalence of the etiologic agents varies with
children less than five years of age have 3.3 geographical area(1,9-12).
diarrhoeal episodes per year, and more than one- For most patients, the illness is a self-limited
third of the deaths in this age group are associated one. But, disease can cause severe fluids and
with diarrhoea. Therefore, every year there are electrolytes loss, which require prompt treatment.
approximately 1.5 billion diarrheic episodes and 4 The management of acute diarrhoea is based on
million deaths in children less than five years of age replacement of fluids. However, antibiotic might
(most from 6 months to 12 years) .(2-4) be required for the management of the same cases
Maternal socio-demographic factors have been and may reduce the duration of disease, but use is
associated with the risk of diarrhoea in children. restricted due to emergence of resistance or due to
There is increased risk of diarrhoea in children lack of availability in some countries(11-12).
with young mothers, those whose mothers have Unfortunately, many hospitals in developing
low education and those not being taken care of by countries are lacking clinical microbiology
their mothers5. Generally, low socioeconomic status laboratories, and there are not enough studies
of a household has been identified as a risk factor dealing with this issue, because of that the cause
for diarrhoea in children(6). Demographic factors of and prevalence of diarrhoea in children is unknown.
a child which can play a role in the risk of diarrhoea In Sudan, there are relatively few studies on this
include age, immunization status, gender and birth aspect but, the real magnitude is not well known.
weight(6-8). The aim of this study is to determine the common
A variety of bacterial, viral and parasitic pathogens bacterial etiology and antibiotic susceptibility of
have been associated with diarrhoeal disease. The diarrhoeal diseases among children under 5 years
most common bacteria responsible for diarrhoeal old.

SUDANESE JOURNAL OF PUBLIC HEALTH - July 2012, VOL. 7 No. 3 93 ‫ العدد الثالث‬- ‫ المجلد السابع‬- ‫المجلة السودانية للصحة العامة‬

original article Bacterial etiology of diarrhoeal diseases in children
under 5 years old in Ombadda Hospital-Sudan

Methods and materials bile salt sucrose (T.C.B.S.) medium. Colonies were
Study design: further processed by using suitable biochemical
Descriptive case study was carried out to determine tests. Suspected Salmonella species, Shigella species
common bacterial aetiology of diarrhoeal diseases and Vibrio cholera were further confirmed by using
in the children under 5 years old and their antibiotic serological test. All E. coli isolates were also tested
susceptibility. by polyvalent 2, 3, 4 and O157:H7 antisera(1, 12).
Antibacterial susceptibility tests were performed
Study population and area: on Mueller-Hinton agar using Kirby-Bauer
Children less than 5 years old complaining of technique. The zone of inhibition was measured by
diarrhoea and attending Ombadda hospital and a ruler, recorded and compared with Clinical and
Omdurman paediatric hospital were included. Laboratory Standards Institute (CLSI) chart(13).

Sampling and Sample size: Ethical consideration
None probability sampling was under taken. Informed consent of the parents were taken.
Convenient samples of one hundred patients Positive cases were reported to the doctor. No fees
were asked to participate in the study. Study were charged.
was conducted during the period from April to
September 2008. Results
One hundred stool specimens were collected
Method of data collection: from children less than 5 years old complaining of
Data was collected from the study participants by diarrhoea. One hundred and thirty eight bacteria
direct interview using structured questionnaire were isolated (Table 1), some of which were
including personnel data, history of antibiotic use, pathogenic bacteria (Table 2).
type of diarrhoea and was filled when receiving The pathogenic bacteria were isolated from all
specimen. age groups in both sexes (Table 3). E. coli strains
were the predominant pathogenic isolates. All E.
Data analysis: coli strains were tested by antisera: polyvalent-2
The data was entered and analyzed using statistical (serogroup O26, O55, O111, O119 and O126),
package for software (SPSS) version 17.0, polyvalent-3 (serogroup O86, O114, O125, O127
frequencies and percentages were computed for and O128), polyvalent-4 (serogroup: O44, O112,
all variables. The data was further processed and O124 and O142) and O157:H7. Five (13.89%)
formulated into figures and tables using Microsoft isolates agglutinated with polyvalent-2, three
excel version 2007 computer program. (8.33%) with polyvalent-3 and 28 (77.78%)
of E. coli were agglutinated with neither
Laboratory methods: polyvalent 4, nor O157:H7. Other serogrouping
Stool or rectal swabs from 100 patients (50 of them antisera were, unfortunately, not available.
from Umbadda and other 50 from Omdurman Vibrio cholerae was isolated from two patients.
paediatric hospital) were studied. Direct microscopic The isolates were serogroup O1, serovar Inaba.
examination by wet preparation and smears stained Twenty two percent of study group were on
with basic carbol fuchsin were performed. In case antimicrobial treatment before collection
of delaying sample processing for more than one of stool samples for culture. Their stool
hour and less than 24 hours; Cary- Blair’s transport culture showed no pathogenic bacteria.
medium was used for preserving samples at 4°C and Antimicrobial susceptibility testing was
also inoculated in selenite F broth at 37°C for up to performed on all pathogenic isolates. E.coli
12 hours. ATCC 25922 was used as a control strain.
Samples were cultured on MacConkey, Sorbitol All isolates (except V. cholerae) were susceptible to
MacConkey, Xylose Lysine Deoycholate (XLD) cefuroxime and ceftriaxone. All E.coli strains were
agar plates and Selenite F broth (sub- cultured on resistant to amoxicillin (Table 4). Antimicrobial
XLD agar after 8-12 hours). Also Campylobacter susceptibility testing of V. cholerae against
selective medium (Skirrow’s) were used. Samples doxycycline, amoxicillin and co-trimaxazole was
from cholera suspected patients were inoculated in done. The two isolates of V. cholerae were susceptible
alkaline peptone water, incubated at 37°C for 5 to 8 to doxycycline and amoxicillin but one isolate was
hours, and then subcultured on thiosulphate citrate susceptible to co-trimoxazole.

SUDANESE JOURNAL OF PUBLIC HEALTH - July 2012, VOL. 7 No. 3 94 ‫ العدد الثالث‬- ‫ المجلد السابع‬- ‫المجلة السودانية للصحة العامة‬

original article Bacterial etiology of diarrhoeal diseases in children
under 5 years old in Ombadda Hospital-Sudan

Table1: Types and numbers of the isolates Number Isolates
36 E. coli
Percentage 68 Other coliforms*
26.09 % 15 Proteus vulgaris
49.28 % 8 Enterococcus faecalis
10.87 % 6 Salmonella paratyphi B
5.80 % 2 Salmonella typhi
4.35 % 2 Vibrio cholera
1.45% 1 Shigella flexneri
1.45 % 138 Total
0.72 %
100 %

* Including Klebsiella spp,Citrobacter spp and Enterobacter spp

Table 2: Frequency of pathogens isolated from stool samples

Percentage Number Isolates

42.11 % 8 E.coli

31.58 % 6 Salmonella paratyphi B

10.53 % 2 Salmonella typhi

10.53 % 2 Vibrio cholera

5.26 % 1 Shigella flexneri

100 % 19 Total

Table 3: Distribution of isolated pathogenic bacteria according to age and sex

Total 2—5 Years 1—2 years Less than 1 year Isolates

Female Male Female Male Female Male Escherichia coli*
Escherichia coli **
4 (21.2%) - 11 - - 2
S paratyphi B
4 (21.2%) - - 1111 Salmonella typhi

6 (31.6%) 1 - 13 - 1 Vibrio cholera
Shigella flexneri
2 (10.5%) 1 1 - - - -
Total
2 (10.5%) -2- - - -

1 (5.0%) -1- - - -

19 (100%) 2 (10.5%) 5 (26.3%) 3 (15.8%) 4 (21.2%) 1 (5.0%) 4 (21.2%)

* Including Polyvalent 2: serogroup O26, O55, O111, O119 and O126
** Including Polyvalent 3: serogroup O86, O114, O125, O127 and O128.

Table 4: Antibacterial susceptibility of the isolates

Number of isolates Ax Co Ci Cu Number Isolates
susceptible to Ac
8 (100%) 8 (100%) 8 (47.1%) Escherichia coli
6 (75%) 0 2 (25%) 6 (100%) 6 (100%) 6 (35.2%) S paratyphi B
2 (100%) 2 (100%) 2 (11.8%) Salmonella typhi
6(100%) 6 (100%) 6 (100%) 1(100%) 1 (100%) 1 (5.9%) Shigella flexneri

2 (100%) 2 (100%) 2 (100%)

1 (100%) 1 (100%) 1 (100%)

Keys: Cu: cefuroxime, Ci: ceftriaxone, Co: cotrimoxazole, Ax: amoxicillin, Ac: amoxicillin / clavulanic acid.

SUDANESE JOURNAL OF PUBLIC HEALTH - July 2012, VOL. 7 No. 3 95 ‫ العدد الثالث‬- ‫ المجلد السابع‬- ‫المجلة السودانية للصحة العامة‬

original article Bacterial etiology of diarrhoeal diseases in children
under 5 years old in Ombadda Hospital-Sudan

Discussion compared to the moderately low cost of amoxicillin,
The study showed that 19% of the cases had which may lead to misuse of the low cost drugs.
diarrhoeal disease caused by bacterial isolates and The V.cholerae isolates were susceptible to
this is less than a study from Tanzania which showed doxycycline and amoxicillin (the drugs of choice
that 33% of isolates were of bacterial origin(14). This for adults and children, respectively). However, one
could be partly due to fact that 22% of the children isolate of V.cholerae was resistant to co-trimoxazole.
had a history of antibiotic use prior to admission. The present study showed high proportion of
Diarrhaegenic E.coli especially Enteropathogenic bacterial diarrhoea among children less than five
E.coli (EPEC) was the predominant isolate (42.11%), years old. The most common causative agent is
followed by Salmonella paratyphi B (31.58%), EPEC which is not part of routine investigation of
Salmonella typhi (10.53%) V.cholerae (10.53%) and stool culture in all of the laboratories in Sudan.
Shigella flexneri (5.26%). This result coincides with Further study including parasitic, fungal, bacterial
the results of studies carried out in the last decades and viral surveillance with more advanced facilities
in Bangladesh, Tanzania and Brazil(15-17). However, and more numbers of antimicrobial agents should
other studies have showed other enteric pathogens be included.
as a common cause of diarrhoeal diseases in children
and this seems to vary geographically(18-19). In this Acknowledgement
study the identification of diarrheic E.coli was based We are grateful to Nour Eldin Ahmed in Laboratory
on biochemical reactions and antisera against O and administration. Our thanks extend to our colleagues
H antigens, but some polyvalent and monovalent who helped us in the collection of specimens.
antisera against O and H antigens of diarrheic E.coli
were not available, this may affect the results of the References
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under 5 years old in Ombadda Hospital-Sudan

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SUDANESE JOURNAL OF PUBLIC HEALTH - July 2012, VOL. 7 No. 3 97 ‫ العدد الثالث‬- ‫ المجلد السابع‬- ‫المجلة السودانية للصحة العامة‬