Virulence 1:3, 130-133; May/June 2010; © 2010 Landes Bioscience
Virulence 1:3, 130-133; May/June 2010; © 2010 Landes Bioscience
Asymptomatic bacteriuria among HIV positive
130 Virulence Volume 1 Issue 3
*Correspondence to: Olutosin A. Awolude; Email: firstname.lastname@example.org
Submitted: 11/17/09; Revised: 02/02/10; Accepted: 02/03/10
Previously published online: www.landesbioscience.com/journals/virulence/article/11384
Asymptomatic bacteriuria (ASB) is defined as the quantitative
growth of bacteria, greater than or equal to 105 colony forming
units per milliliter urine of the same organism, on aseptically col-
lected midstream urine specimens, in the absence of symptoms of
urinary tract infection.1-3
The prognostic significance of ASB resides in the observation
that persons with ASB in certain medical conditions, such as dia-
betes mellitus and pregnancy, are at increased risk of pyelone-
phritis and renal impairment.4-6 If asymptomatic bacteriuria is
not treated in pregnancy up to 40% of the patients will develop
urinary tract infection (UTI) and approximately, 25–30%
of women will develop acute pyelonephritis.7 It has been esti-
mated that treatment of asymptomatic bacteriuria would lead
to approximately a 75% reduction in the incidence of pyelone-
phritis.7 Asymptomatic bacteriuria has been associated with pre-
term delivery, fetal loss and preeclampsia.8 Today, screening for
asymptomatic bacteriuria have become standard of care in some
obstetric units to prevent these complications.
The prevalence of ASB in normal pregnant population has
been quoted to range from 2–10%9-11 and in Nigeria a preva-
lence of 4–14.1% have been documented.12 Prevalence has been
found to be, generally, increased with age, sexual activity and
parity. However, higher prevalence have been found in spe-
cific clinical conditions like anatomic and functional urinary
The prognostic significance of asymptomatic bacteriuria resides in the observation that the prevalence is, relatively, high
in persons with certain medical conditions, such as diabetes mellitus and pregnancy. This prevalence might, even, be
higher in patients with human immunodeficiency virus infection. Hence, this study set out to determine the prevalence
of asymptomatic bacteriuria among symptom free and newly enrolled HIV infected pregnant women attending PMTCT
unit of Antiretroviral Clinic of University College Hospital, Ibadan, Nigeria between 1st May and 30th September 2007.
Information was obtained on the socio-demographic characteristics of the subjects, CD4 count and viral load. Micro-
bial culture was carried out on aseptically collected urines from the patients. Statistical analysis was done with SPSS 12
package. There were 161 analyzable samples from the participants. The mean age and gestational age at presentation
of participants was 30.49 ± 4.3 years and 27.3 ± 3.2 weeks, respectively with modal parity of 2. Twenty-five (15.5%) of the
urine samples significantly grew bacteria. The CD4 cells were significantly lower and the viral loads significantly higher
(250.52 vs. 355.57 cells/mm3; 88,731 vs. 55,384 copies/ml; p = <0.0000) for the urine culture positive patients. Eshcherichia
coli were isolated in 48%, Proteus in 16.0%, Klebsiella in 8.0% and Staphylococcus aureus in 28.0% of the urine positive cul-
tures. The study showed that the prevalence of asymptomatic bacteriuria among PLWHAs is high. The microbial isolate
from the urine samples were not different from those of HIV-negative patients.
Olutosin A. Awolude,1,* Olubukola A. Adesina,1 Adesina Oladokun,1 W.B. Mutiu2 and Isaac F. Adewole1
1Department of Obstetrics and Gynaecology; and 2Department of Medical Microbiology; University College Hospital; Ibadan, Nigeria
Key words: asymptomatic bacteriuria, HIV positive, pregnant women, prevalence
tract abnormalities, lower socio-economic status, anaemia and
immunosuppressive state like in sickle cell trait, diabetes mel-
litus13-15 and, possibly, human immunodeficiency virus (HIV)
Human immunodeficiency virus (HIV), a chronic infection
associated with progressive immune dysfunction, appears to
increase risk for developing significant bacteriuria in patients.16
In HIV infection co-morbidity with other organisms is common
and this may impact on the pregnancy outcome in these patients.
Such organisms may include those of asymptomatic bacteriuria.
The diagnosis of ASB is based on isolation of microorganisms
with a colony count >105 organisms per millilitre of urine in a
clean-catch specimen.16 The patient should be instructed to clean
the vulva area from front to back to avoid contamination of the
In all studies of asymptomatic bacteriuria, Escherichia coli is
the most common organism associated with bacteriuria, repre-
senting at least 80% of isolates, with other gram-negative rods
and certain gram-positive organisms including Staphylococcus
saprophyticus and enterococci occasionally being isolated.17
To date there is no data to describe the prevalence of ASB
among HIV infected pregnant women in our environment. This
study was undertaken to estimate the prevalence and possible risk
factors for ASB in pregnant women undergoing care in an HIV
prevention, treatment, care and support program in a tertiary
center in Nigeria.
www.landesbioscience.com Virulence 131
(28%), Proteus mirabilis (16%) and Klebsiella species (8%). All of
these organisms were grown in pure cultures (Fig. 1).
The prevalence of asymptomatic bacteriuria was 15.5% among
the studied HIV possible pregnant women accessing the PMTCT
interventions at the ART program at the University College
Hospital, Ibadan. This rate of asymptomatic bacteriuria is higher
than the range generally quoted for non-pregnant and pregnant
women.9,10 This can be associated with the fact that women
included in this study were recruited from a tertiary hospital
which serves as a referral centre for most ill patients and, as such,
may represent a population with more severe disease.
The use of a clean-void midstream method of collection and
quantitative urine cultures to differentiate infection from con-
tamination is well established.1-3 This method has been shown
to provide at least 80 percent likelihood that a voided midstream
urine specimen will provide the necessary sample to detect high
colony count if present.4,5
The infecting organisms identified in this study are in keeping
with commonly isolated bacteria in other studies of asymptom-
In this study 48% of 25 cultures showing significant bacte-
riuria grew E. coli. These numbers, though considerably lower
than those reported in similar studies,2,3 still follow the pattern of
E. coli being responsible for majority of the microbes implicated
in ASB. The 28% isolated staphylococcus aureus might indi-
cate the risk of opportunistic infections to which HIV positive
patients are particularly prone to. The possibility of nosocomial
infection as shown in a similar study in non-pregnant women24
can explain this finding.
Opportunistic infections (OIs) are important co-morbidities
in PLWHAs18 and they influence the morbidity and mortality
due to HIV infections. This study showed that in seven of the
patients without bacteriuria and four patients with bacteriuria,
there was growth of candida in the urine. This highlights the
need for early screening and also the need to increase awareness
in healthcare providers, in order to improve decision making
regarding prophylaxis for prevention and appropriate therapeutic
There are few studies with which to compare our data on risk
factors. In other studies prevalence of asymptomatic bacteriu-
ria was found to be higher with clinical conditions like diabetes
mellitus and sickle cell disease due to their immunosuppressive
nature. It is not, therefore, surprising the high prevalence found
in this study.6,14,19,20
The present study demonstrated a significant and indepen-
dent association between the presence of ASB and both CD4
counts and viral load. These results imply that the more morbid
the patients the higher the risk of asymptomatic bacteriuria and,
possibly, the more vulnerability to bacterial and other opportu-
Maternal age or type of marriage has no effect on the preva-
lence of asymptomatic bacteriuria and parity had no influence
either unlike other studies.21,22 There was no correlation between
A total of 165 urine samples were collected. However four sam-
ples were excluded from analysis—two patients were on antibiotic
treatment, one sample was wrongly labeled and one sample was
processed but found to be contaminated—leaving 161 analyz-
able samples. A total of 25 cases of asymptomatic bacteriuria were
seen out of 161 HIV positive obstetric patients screened during
the study period. This gives prevalence of asymptomatic bacte-
riuria of 15.5% among these patients. There was no case of more
than one bacteria isolated. However, four of the urine specimen
had, in addition to bactereria, Candida albicans isolated.
Table 1 shows the sociodemographic characteristics of the
patients. The mean age and gestational age at presentation of
participants was 30.49 ± 4.3 years and 27.3 ± 3.2 weeks (30.52
years and 30.46 years; 27.4 weeks and 29.1 weeks, respectively,
for patients with and without significant bacteriuria respectively)
and the modal parity was 2 for patients with or without signifi-
cant bacteriuria with a range of 0–3. Forty-one percent of the
participants were traders, 85.7% were of Yoruba tribe and 60.9%
were Christian. One hundred and fifteen, representing 71.4% of
the participants, had at least secondary education.
Table 2 shows the laboratory results of the participants.
While the packed cell volume was not significantly different
between those with and without significant bacteriuria (28.16%
and 27.96% respectively), the mean value was generally low at
28.06%. The CD4 counts were significantly lower among the
patients with significant bacteriuria compared with those without
significant bacteriuria (250.52 cells/mm3 vs. 355.57 cells/mm3;
p < 0.0001 at 95% CI). Similarly, the viral loads of the patients
with asymptomatic bacteriuria was significantly higher compared
with those without asymptomatic bacteriuria (88,731 copies/ml
vs. 55,384 copies/ml; p < 0.0001 at 95% CI).
There were 32 patients with abnormal midstream urine
results. Twenty five samples grew identifiable bacteria of which
four were with mixed candida growth (2 each for Klebsiella species
and E. coli). This gave a prevalence of asymptomatic bacteriu-
ria of 15.5% among this group. There were seven culture results
of pure candida growth. Twelve of the 25 positive samples for
bacteria (48%) grew E. coli in significant quantity. This was the
commonest organism cultured in this study. Other urinary tract
pathogens identified in this study included: Staphylococcus aureus
Table 1. Socio-demographic characteristics of asymptomatic
bacteriuria positive and negative patients
Mean age (years)30.5230.460.9823
Type of marriages (n/%)
Monogamy17 (68)100 (73.5)0.9523
Polygamy8 (32)36 (26.5)0.8469
Mean gestational age at
Modal parity (n) 2.02.00.2474
Mean packed cell volume (%)28.1627.960.8526
132 Virulence Volume 1 Issue 3
the same day for microbiological culture. Samples were imme-
diately processed. Routine microscopy of centrifuged urine
sediments was done and culture was on Cysteine-Lactose-
Electrolyte-Deficient (CLED) and blood Agar plate. There was
incubation of innoculated agar plates at 37°C for 24 hours and
then identification of suspected pathogens was by biochemical
and sugar utilization tests. Antibiotic sensitivity testing was by
disc diffusion technique. Isolates were considered significant if
there were ≥105 colony forming units/mL (CFU/mL) with 2 or
less isolates; doubtful significance if 104–105 CFU/mL; insignifi-
cant if <104 CFU/mL. Mixed growths, in any count, of more
than two organisms were considered to be contaminated.
Blood samples were also taken for the patients CD4 counts,
viral load, packed cell volume along with other tests for Pre-
assessment for eligibility for antiretroviral treatment or PMTCT
services which include haematologic studies, blood chemistry
studies, liver function tests, serum lipid studies and blood sugar
levels. A proforma was designed to obtain information on the
socio-demographic characteristics of the participants.
the packed cell volume of the patients and ASB. The generally
low packed cell volume of the patients may reflect the known
haemopoetic suppressive effects of HIV infection.23,24
In conclusion, this study has shown a high prevalence of ASB
among HIV positive pregnant women. However, the result is
similar to those seen in patients with other immune suppres-
sive clinical conditions like diabetes mellitus and sickle cell dis-
ease.19,20 The risk factors for ASB in this patients were low CD4
counts and high viral load.
The participants comprised a group of HIV positive pregnant
women managed in the PMTCT arm of the antiretroviral ther-
apy (ART) clinic of University College Hospital (UCH), Ibadan.
This Antiretroviral treatment programme provides services for
HIV positive men, women and children. The PMTCT pro-
gramme provides health education, pre- and post-test counseling,
provision of antiretroviral drugs for pregnant women and infants,
ongoing counseling before and after birth, infant feeding services,
determination of status for infants at birth, 6 weeks, follow-up of
the mother-infant pairs and provision of care and support for the
entire families affected by HIV. The study was conducted among
consenting patients in research protocol on Safety, Adherence
and Effectiveness of Antiretroviral Therapy in Pregnant HIV-
Infected Nigerians between 1st May and 30th September 2007.
This protocol, which was approved by the Institutional Review
Committee of University College Hospital and University of
Ibadan, Nigeria, included screening for genitourinary infections
as part of the pre-assessment evaluations prior to enrolment into
treatment or care arm of the program.
Aseptically collected midstream urine samples (MSUs) were
obtained from the symptom free attendees of clinic and sent on
Table 2. Laboratory results
Laboratory parameter Patients with positive bacteriuria
Patients with negative
Urine Bacteria Culture
Klebsiella Spp.2 (8%)
Candida mixed with E. coli
Candida mixed with Klebsiella2
Packed cell volume
88,731 copies/ml 55,384 copies/ml<0.0001
Figure 1. Microbial isolate from the urine specimen.
www.landesbioscience.com Virulence 133 Download full-text
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