Nigerian Journal of
Paediatrics 2011;38 (3):136 -
141
ORIGINAL
Onalo R
Rate
of isolation of streptococcus species
Adeleke SI
Nwalorzie C
from
children with bacterial infections:
Njoku R
an
indication for introduction of
streptococcal vaccines
Received:18th May
2011
Abstract
Background:
Version 3.5.1.
Statistical
Accepted: 19th July
2011
Streptococcus species
are among
significance was set at
p < 0.05.
the commonest bacterial
causes
Results: A
total of
2,247 samples
Onalo R ( )
Adeleke SI,
of childhood morbidity
in
were received during
the study
Nwalorzie C
developing
countries.
period. Of the 1,242
bacteria
Department of
Paediatrics,
Streptococcal diseases
in children
isolated, 502 (40.4%)
were
University of Abuja
Teaching
have not been as
well
Staphylococcus
aureus ,
232
Hospital,
Gwagwalada,Abuja
characterized in
Nigeria as it has
(18.7%) were Escherichia coli and
E-ma il:
richardonalo@yahoo.com
been in industrialized
countries.
146 (11.8%) were
Streptococcus
The rudimentary nature
of public
Tel:
+2348037017678:
species: 78 were
isolated from
health surveillance
makes the true
blood, 9 from sputum,
11 from
epidemiology of the
disease
Njoku R
throat swabs and 28
from other sites
difficult to ascertain.
The
while urine and eye
swabs had 10
Department of
Medical
predominance of Streptococcus
each. One hundred and
six (72.6%)
Microbiology,
University of
pneumoniae in the causation of
of the streptococci
were from
Abuja Teaching
Hospital,
invasive diseases has
led to the
children aged 5 years
and below.
advocacy of inclusion
of
Gwagwalada, Abuja
Nigeria
Most of the
Streptococci (88.1%)
pneumococcal vaccine in
the
were untyped. Among the
17
National Programme
on
Streptococcal isolates
typed, 10
Immunization. However,
local
were
Streptococcus
pneumoniae
data critical to inform
on vaccine
a n d
t h r e e
w e r e
g r o u p
B
deployment are scarce,
thus the
Streptococcus.
need for the present
study.
C o
n c l u s i o n :
Streptococcal
Objective:
To study the rate
of
infections remain an
important
isolation of
Streptococcus species
cause of severe disease
in children
from children aged zero
to 15
in Nigeria. The use of
effective, safe
years, with suspected
bacterial
and affordable vaccine
could
infections.
significantly reduce
morbidity from
M a
t e r i a l s
a n
d
M e
t h o d s :
Laboratory records of
results of
these infections, thus
suggesting the
bacteriological studies
of samples
need for more studies
to conclude
from children with
suspected
o n
s t r e p t o c o c c a
l
v a c c i n e
bacterial infections in
University
deployment.
of Abuja Teaching
Hospital from
January 2008 through
December,
K e
y
w o
r d s :
Streptococcal
2010 were retrieved and
analyzed
infections, Nigeria,
Streptococcal
for bacterial growth.
Data analysis
vaccines
Introduction
in developing countries
like Nigeria. The
predominance of Streptococcus
pneumoniae in the
The genus Streptococcus
comprises of more than 30
causation of invasive
diseases has lead to the
species.
Streptococcus
pneumoniae ,
group A
advocacy of inclusion
of pneumococcal vaccine in
the National Programme
on Immunization.
2
Streptococcus and group
B Streptococcus are the
most common causes of
human streptococcal
However, there is
paucity of data in Nigeria on the
infections.
1
These organisms are
among the
burden of streptococcal
infections in children thus
commonest bacterial
causes of childhood morbidity
making the debate for
vaccine deployment
inconclusive
137
It is hopeful that data
generated from this study may
Statistical analysis
offer ample evidence
for the need for streptococcal
vaccine inclusion in
national immunization
Statistical analysis
was done using Epi Info software
programmes.
version 3.5.1(CDC,
Atlanta, GA, USA, 2008).
Frequency tables were
generated while Chi square
and Fischer's exact
tests were used to test associations
between categorical
variables. Statistically
Objective
significant difference
level was set at p < 0.05.
To study the rate of
isolation of Streptococcus
species from children
aged zero to 15 years, with
suspected bacterial
infections.
Results
A total of 2,247
samples were received during the
study period, of which
918 were blood samples, 400
Materials and Methods
were urine, 292 were
stool, 226 were cerebrospinal
fluid, 19 were sputum,
344 were swabs from various
The study was
retrospective, on bacteriological
body sites, 43 were
aspirates while 5 specimens were
samples from children
aged 15 years and below that
not properly labeled to
reveal their site of origin. Of
were evaluated for
suspected bacterial infections at
the 1,247 (55.5%)
specimens that yielded growths,
the Paediatric
Department of University of Abuja
1,234 yielded 1,242
bacteria while 13 yielded 13
Teaching Hospital,
Gwagwalada, Abuja. The
candida species.
Bacterial growth in 1226 samples
hospital is a tertiary
institution at the centre of
was monomicrobial while
8 samples yielded
Nigeria and serves as a
major paediatric referral
polymicrobial growths.
The rate of bacterial yield
centre for communities
in the Federal Capital
from the various
samples is thus: blood - 62.6%, urine
Territory and those of
the neighbouring states in
- 45.5%, stool - 43.5%,
cerebrospinal fliud - 8.4%,
North central
Nigeria.
swabs from various
sites - 72.1%. Of the 1,242
bacteria isolated, 502
(40.4%) were Staphylococcus
Samples for
bacteriological studies were processed
aureus ,
232 (18.7%)
were Escherichia coli and 146
as recommended by
Cheesbough et al. For blood
3
(11.8%) were
Streptococcus species. Table 1.
culture, 2 ml of venous
blood was collected
aseptically after
thorough skin preparation with 70%
Table 2 shows the rate
of isolation of Streptococcus
alcohol. The blood
samples were introduced into
species from the
various samples analyzed. About
thioglycollate broth
through a sterile needle in the
76.0% of isolates from
throat swabs were
ratio of one part of
blood to five parts of the broth and
Streptococcus species
while 36.8% of organisms
incubated at 37 C for
seven days. The cultures were
o
recovered from the
cerebrospinal fluid, 36.0% of
examined daily for
evidence of bacterial growth such
bacteria cultured from
the sputum, 20.8% of the eye
as turbidity, clot and
gas formation. In samples that
swabs isolates, 13.6%
of isolates from blood and
showed such evidence,
sub-cultures onto chocolate
8.3% of those recovered
the ear swabs were equally
and blood agar plates
were performed and incubated
Streptococcus species.
Similarly, a higher proportion
at same temperature for
24 to 72 hours. Organisms
of the Streptococcus
species (72.6%) were recovered
isolated were
identified by conventional methods.
3
from samples taken from
children aged 5 years
Smears of swabs of eye,
ear, umbilical and vaginal
(Figure1).
discharges as well as
those of wound and skin swabs,
cerebrospinal fluid and
urine samples, were
Analysis of the
contribution of Streptococcus species
inoculated on
MacConkey, chocolate and blood agar
to infections in
children is compared with those of
plates and incubated
for 24 to 48 hours and the
other bacterial
pathogens on Table 3, which show that
bacteria grown were
identified using standard
Streptococcus organisms
is more associated with
methods.
3
respiratory tract
infections, subarachnoid space
st
Bacteriological results
between 1 January 2008 and
infections and blood
stream infections . Majority of
31 December, 2010 were
collated and analyzed to
st
the Streptococcus
species isolated (88.1%) were not
identify the pattern
and distribution of bacterial
further characterized,
however, Streptococcus
growth.
pneumoniae accounts
for 7.5%
(10), group
B beta
haemolytic
Streptococcus was 2.2% (3) while
anaerobic Streptococcus
was 4(3.0%). Four cases of
Streptococcus pneumoniae were isolated
from the
sputum, three from
throat swab and one each from the
cerebrospinal fliud,
pleural tap and the stool.
138
Table 1 : Distribution of isolates based on
the site of isolation
Bacteria
Sources of bacterial
isolates
Blo
Urin
Stoo
CS
Ey
Ear
Sput
Wou
Thro
Other
Total (%)
od
e
l
F
e
um
nd
at
s
Staphylococcus
311
64
3
6
24
27
16
17
4
30
502(40.4)
aureus
Streptococcus
78
10
1
7
10
9
9
4
11
7
146(11.8)
species
Escherichia coli
55
55
89
1
3
10
-
9
1
9
232(18.7)
Klebsiella
species
46
40
7
3
7
10
4
5
2
16
140(11.2)
Pseudomonas
6
2
2
-
2
51
-
13
-
13
96(7.7)
species
79
11
25
2
1
4
-
1
-
3
126(10.1)
Other bacteria
TOTAL
575
182
127
19
47
11
29
49
18
78
1
Others refer to
aspirates from joint space, pleural cavity, gastric contents, peritoneal fluid
(ascites), pus and
discharges from
umbilicus, vaginal as well as swabs of skin lesions and those of non-specified
sites
Table 2: Rate
of isolation
of Streptococcus
species from
laboratory samples
with positive
bacterial growth.
SAMPLE
Number
of
Number of strep
Proportion (%) of
positive cases
species isolated
strep among
N
(%)
N
(%)
positive cases
Blood (n = 918)
575(62.6)
78 (8.5)
13.6
Stool (n = 296)
127(43.5)
1(0.3)
0.8
Urine (n = 400)
182(45.5)
10 (2.5)
5.5
Cerebrospinal fluid (n
= 226)
19(8.4)
7 (3.1)
36.8
Eye swabs (n =
66)
48(72.7)
10 (15.2)
20.8
Ear swabs (n =
129)
111(86.1)
9 (7.0)
8.3
Wound swabs (n =
57)
49(85.9)
4 (7.0)
9.5
Throat swabs (n =
19)
18(94.7)
11 (57.9)
75.9
Sputum (n = 39)
29(74.4)
9 (23.1)
36.0
Aspirates+ (n =
43)
25(58.1)
4 (9.3)
16.0
Skin swabs (n =
21)
11(52.4)
-
-
Vaginal swabs (n =
21)
11(52.4)
2 (9.5)
18.2
Umbilical swabs (n =
8)
8(100.0)
-
-
Miscellaneous** (n =
5)
3(60.0)
1 (20.0)
33.3
** Miscellaneous = Site
of specimen collection was not stated in 5 of the analyzed samples.
+ refer to aspirates
from joint space, pleural cavity, gastric contents, peritoneal fluid (ascites)
and abscesses.
80%
70%
60%
50%
0-5
years
6-10
years
40%
11-15 years
30%
Unstated age
20%
Figure 1 : Proportion of
Streptococcus
10%
species isolated from
various age-groups
0%
139
Table 3 : Comparison of the contribution of
Streptococcus species to those of other commonly isolated
bacteria in the
causation of infection** in children.
Bacteria
Site of
isolation
Blood
CSF
Ear
Resp tract
Others
(n=575)
(n=19)
(n=109)
(n=47)
(n=484)
Strep
78
7
9
20
32
(n=146)
Staph
311
6
27
20
138
(n=502)
2
χ
3.68
FET
0.03
16.79
1.52
P
0.0791
0.0125
0.8732
<0.0001
0.2149
Strep
78
7
9
20
32
(n=146)
E. coli
55
1
11
1
164
(n=232)
χ
2
33.41
FET
0.13
27.59
83.44
P
<0.0001
0.0063
0.7145
<0.0001
<0.0001
Strep
78
7
9
20
32
(n=146)
Klebsiella
46
3
12
6
73
(n=140)
χ
2
11.49
FET
0.31
6.57
26.81
P
0.0007
0.0501
0.5799
0.0104
<0.0001
CSF = Cerebrospinal
fluid; Resp tract = Respiratory tract; Staph =
Staphylococcus aureus ; Strep =
Streptococcus species;
E. coli = Escherichia coli
** Isolation of
bacteria from specimens taken from stated body sites is considered as infection
of that site
+Others refer to
isolates from stool, urine, eye, ear, wound and aspirates from joint space,
pleural cavity,
gastric contents,
peritoneal fluid (ascites), pus and discharges from umbilicus, vaginal as well
as swabs of
skin lesions and those
of non-specified sites
Discussion
of Onipede
et al from Ile-Ife, South
western Nigeria
9
and Nwadioha et
al from Kano, North western
Nigeria. Differences in
methodology may account
10
Streptococcal organisms
are common bacterial
for this; whereas the
report from Ile-Ife considered
9
agents causing
childhood morbidity and mortality.
Almost all organ
systems could be affected by these
only patients with deep
seated infections, the present
agents and there are
indications that the incidence of
study included
superficial infections. Similarly, the
report from Kano, which
revealed isolation of only
10
infections with these
agents may be increasing. The
4
overall prevalence of
streptococcal infections in the
ten cases of Streptococcus
pneumoniae from 3840
present study is 11.8%.
However, with further
blood culture samples,
also excluded results of
categorization, 75.9%
of isolates from throat swabs,
bacteriological studies
of swabs of body discharges as
36.8% of organisms
recovered from the
well as urine,
cerebrospinal fluid and stool specimens.
cerebrospinal fluid and
36.0% of bacteria cultured
Reports are however
consistent on the role of
from the sputum were
Streptococcus species.
streptococcal organisms
in invasive diseases.
The high isolation rate
of streptococcus species from
The high isolation rate
of streptococcus species from
the cerebrospinal
fluid, sputum, throat swabs and
the cerebrospinal
fluid, sputum, throat swabs and
blood in the present
study corroborates the findings
blood specimens from
children with suspected
of other researchers
and emphasizes the role of
5-8
bacterial meningitis,
pneumonia, pharyngitis and
streptococcal organisms
in systemic infections in
septicaemia in the
present study is a pointer to the
children. Although, the
11.8% streptococcal
magnitude of invasive
streptococcal infections in the
infections prevalence
rate in this study is lower than
area of study and
suggests the need for preventive
figures from
EastAfrica, it is much higher than those
5
strategies aimed at
curtailing the immediate and late
140
untoward
effects
of
invasive
streptococcal
Although groupAand
group B streptococcal vaccines
Infections.
Although
retrospective
analysis
of
are at various stages
of development, pneumococcal
bacteriological samples
may not be the best indicator
vaccine has been
licensed for use in children and have
of the burden of
bacterial infections in a community,
been shown to be
associated with a 98% reduction in
they nevertheless, give
a clue to the magnitude of
rates of bacteraemia
and meningitis and a 67%
morbidity caused by
pathogenic organisms and the
reduction in rates of
otitis media due to vaccine
serotypes.
12
distribution of the
various agents among susceptible
Since it was marketed
in 2000,
individuals.
In
resource-limited
countries,
widespread use of this
vaccine in developed countries
retrospective analysis
may be the main source of
has caused a dramatic
decline in the incidence of
aetiological
information as bacteriological data from
invasive pneumococcal
disease among infants and
children.
12
community settings are
not readily available due to
lack of laboratory and
culture facilities in most
primary and secondary
health facilities.
8
The high cost of
conjugate pneumococcal vaccine
(approx US $50 per
dose) and the challenges of
From the result of the
present study, one may
developing effective
and safe vaccines against group
speculate that the
control of streptococcal infections
A and group B
streptococci makes it unaffordable for
all but the wealthiest
of countries,
13,14
in children may
drastically reduce the burden of
thus for low-
bacterial meningitis,
bacterial pneumonia, bacterial
income countries to
introduce such vaccines, there
pharyngitis,
septicaemia
and
possibly,
the
has to be a strong
political commitment. Going by the
postinfectious
syndromes of acute rheumatic fever
burden of streptococcal
infections in the present
and
glomerulonephritis.
study, under-five
morbidity is unlikely to reduce
significantly without
concerted efforts at the control
The
experience
over
the
years,
of
national
of
streptococcal
infections;
hence
introducing
immunization
programs,
demonstrates
that
vaccines
against
streptococcus
species,
though
immunization is one of
the effective public health
expensive, may be
lifesaving and cost-effective.
strategies. Rapid
deployment and use of traditional
Further studies are
therefore recommended on disease
vaccines against
childhood killer diseases have been
burden and the cost
implication of streptococcal
the most important
contributors to reductions in child
vaccines in developing
countries.
mortality
and
increased
life
expectancy
in
developing
countries.
11
However, introducing
new
vaccines into the
National Program on Immunization
requires enormous human
and financial resources
Conclusion
including
engagement
of
national
leaders
responsible for primary
health care services and
The
contribution
of
streptococcal
infections
to
presenting them with
evidence on the burden of the
morbidity in children
is enormous. Introduction of
disease and the
potential impact of new vaccine
effective, safe and
affordable streptococcal vaccine
introduction.
11
could
significantly
alter
the
current
pattern
of
childhood
morbidity
and
thus
warrants
further
exploration.
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