Asymptomatic Bacteriuria among Pregnant Women attending the Outpatient Clinics of Chitwan Medical College teaching hospital in Chitwan

Abstract

Urinary Tract Infection (UTI) refers to both microbial colonization of the urine and tissue invasion of any structure of the urinary tract. Pregnancy enhances the progression from asymptomatic to symptomatic bacteriuria which could lead to pyelonephritis and adverse obstetric outcomes such as prematurity, low-birth weight, and higher fetal mortality rates. This study was undertaken to determine the prevalence of asymptomatic bacteriuria in pregnancy; its causative agents and their antimicrobial susceptibility pattern, and also to determine the relationship between asymptomatic bacteriuria and pyuria. The total number of participants who finished the study was 392. The mean age of the participants was 29.76 ± 6.71(range, 21-37 years). Of the 392 urine specimens processed, 102 (26.0%) showed significant bacteriuria. The commonest organism causing bacteriuria was Escherichia coli. The sensitivity pattern of the isolated organisms revealed that all were sensitive to ciprofloxacin and gentamicin at very high percentage. 200 (51.5%) women had more than 5 pus cells in urine specimens from which 50 (12.75%) had positive cultures. Women with higher number of pus cells in urine specimen had significantly higher asymptomatic bacteriuria (p < 0.0001).In conclusion, screening of bacteriuria in pregnancy and proper treatment must be considered as an essential part of antenatal care in Nepalese community. To prevent asymptomatic bacteriuria complications, all pregnant women should be screened at the first antenatal visit. A negative test for pyuria is not a reliable indicator of the absence of asymptomatic bacteriuria in pregnant women.

Full text

Bijay Aryal et al. IRJP 2012, 3 (11)
Page 78
INTERNATIONAL RESEARCH JOURNAL OF PHARMACY
www.irjponline.com ISSN 2230 – 8407
Research Article
ASYMPTOMATIC BACTERIURIA AMONG PREGNANT WOMEN ATTENDING THE OUTPATIENT CLINIC
OF CHITWAN MEDICAL COLLEGE TEACHING HOSPITAL, CHITWAN, NEPAL
Mamata Sharma Neupane1, Kalpana Sharma Dhakal1, Harish Chandra Neupane2, Shital Adhikari3 and Bijay Aryal4 *
1Department of Nursing, 2Department of Surgery, 3Department of Medicine and 4Department of Clinical Pharmacology,
Chitwan Medical College Teaching Hospital, Bharatpur-10, Chitwan, Nepal
Article Received on: 19/09/12 Revised on: 01/10/12 Approved for publication: 16/11/12
*Email: phrbijayaryal@gmail.com
ABSTRACT
Urinary Tract Infection (UTI) refers to both microbial colonization of the urine and tissue invasion of any structure of the urinary tract. Pregnancy enhances
the progression from asymptomatic to symptomatic bacteriuria which could lead to pyelonephritis and adverse obstetric outcomes such as prematurity, low-
birth weight, and higher fetal mortality rates. This study was undertaken to determine the prevalence of asymptomatic bacteriuria in pregnancy; its causative
agents and their antimicrobial susceptibility pattern, and also to determine the relationship between asymptomatic bacteriuria and pyuria. The total number of
participants who finished the study was 392. The mean age of the participants was 29.76 ± 6.71(range, 21-37 years). Of the 392 urine specimens processed,
102 (26.0%) showed significant bacteriuria. The commonest organism causing bacteriuria was Escherichia coli. The sensitivity pattern of the isolated
organisms revealed that all were sensitive to ciprofloxacin and gentamicin at very high percentage. 200 (51.5%) women had more than 5 pus cells in urine
specimens from which 50 (12.75%) had positive cultures. Women with higher number of pus cells in urine specimen had significantly higher asymptomatic
bacteriuria (p < 0.0001).In conclusion, screening of bacteriuria in pregnancy and proper treatment must be considered as an essential part of antenatal care in
Nepalese community. To prevent asymptomatic bacteriuria complications, all pregnant women should be screened at the first antenatal visit. A negative test
for pyuria is not a reliable indicator of the absence of asymptomatic bacteriuria in pregnant women.
Keywords; asymptomatic bacteriuria, pyuria, antenatal care, urinary tract infection, E.coli
INTRODUCTION
Urinary Tract Infection (UTI) refers to both microbial
colonization of the urine and tissue invasion of any structure
of the urinary tract.1 Bacteria are most commonly responsible
although yeast and viruses may also be involved.
Asymptomatic bacteriuria, in which urine culture reveals a
significant growth of pathogens, that is greater than 105
bacteria/ml, 2 but without the patient showing symptoms of
UTI, can be found in both pregnant and non pregnant women.
Pregnancy enhances the progression from asymptomatic to
symptomatic bacteriuria which could lead to pyelonephritis
and adverse obstetric outcomes such as prematurity, low-
birth weight, 3 and higher fetal mortality rates.4, 5 Although
UTI may not always lead to complications in the mother, it is
still a cause of significant morbidity.6
UTI account for approximately 10 percent of OPD visits by
women, and 15 percent of women will have a UTI at some
time during their life. In pregnant women, the incidence of
UTI can be as high as 8 percent. 1 Pregnant women are at
increased risk for UTI. Beginning in week 6 and peaking
during weeks 22 to 24, approximately 90 percent of pregnant
women develop ureteral dilatation, which will remain until
delivery (hydronephrosis of pregnancy). Increased bladder
volume and decreased bladder tone, along with decreased
ureteral tone, contribute to increased urinary stasis and
ureterovesical reflux. Additionally pregnant women develop
glycosuria, which encourages bacterial growth in the urine.1
These multiple factors contribute to the development of UTI
during pregnancy. The organisms that cause UTI during
pregnancy are the same as those found in non-pregnant
patients. Escherichia coli accounts for 80 to 90% of
infections.2-4 Other gram-negative rods such as
Proteusmirabilis and Klebsiella pneumoniae are also
common. In the 1960s, Kass et al. noted the subsequent
increased risk of developing pyelonephritis in patients with
asymptomatic bacteriuria. 5, 6
Asymptomatic bacteriuria is common, with a prevalence of
10 percent during pregnancy.1,8 Thus, routine screening for
bacteriuria is advocated. Untreated asymptomatic bacteriuria
leads to the development of symptomatic cystitis in
approximately 30 percent of patients and can lead to the
development of pyelonephritis in up to 50 percent.5
Asymptomatic bacteriuria is associated with an increased risk
of intrauterine growth retardation and low-birth-weight
infants. 6, 7
There are a number of conditions associated with an
increased prevalence of asymptomatic bacteriuria in
pregnancy. Low socioeconomic status, sickle cell traits,
diabetes mellitus and grand multiparity have been reported;
each is associated with two-fold increase in the rate of
bacteriuria. 5
A major study comparing normal and high-risk pregnant
women reported 6.0% prevalence in healthy women; 12.2%
rate in diabetic women and 18.7% in women with a previous
history of urinary tract infection.5 Maternal anemia has been
reported to be associated with both asymptomatic bacteriuria
and pyelonephritis, but an association with covert bacteriuria
has not yet been confirmed. Also there is evidence that when
there is no symptom, untreated bacteriuria in pregnancy may
lead to less favorable pregnancy outcomes and complications
like preterm delivery, low birth weight, pre-eclamptic
toxemia and anemia of pregnancy.7, 12 Some studies have
shown that 18 weeks of gestation is the optimal time for
performing screening culture for detecting bacteriuria. 13
The present study was undertaken to determine the
prevalence of asymptomatic bacteriuria in pregnancy; its
causative agents and their antimicrobial susceptibility pattern,
and also to determine the relationship between asymptomatic
bacteriuria and pyuria.
MATERIALS AND METHODS
Sample collection and setting
The study was conducted in outpatient clinic of gynecology
department of Chitwan Medical College Teaching Hospital
and has been approved by Institutional Review Committee of
Chitwan Medical College (CMC-IRC) on August, 2012. A

Bijay Aryal et al. IRJP 2012, 3 (11)
Page 79
total 392 urine specimens were collected from asymptomatic
bacteriuric women during April, 2012 to September, 2012.
All subjects were examined at the first antenatal visit and
maximum gestational age was 18 weeks. None of the patients
had any signs or symptoms of classical UTI on examination.
Asymptomatic bacteriuria was defined as the presence of
≥105/ml colonies of the same bacterial species in two
consecutive midstream urine without any symptom of urinary
tract infection. On each visit, two consecutive midstream
clean catch urine samples, one on the day of the visit and
another on the next day of the visit, were collected in a sterile
wide mouth screw capped container with aseptic precautions.
The patients were individually instructed about the technique
for collecting clean voided midstream urine specimens. All
patients were asked to wipe their labia with soapy water and
rinse well, then after urinating a little in the toilet fill the
container (clean catch method). All the specimens were sent
to the microbiology laboratory and processed on the same
day. Standard microbiological techniques were used in the
culture of all urine specimens and in the identification of the
isolates. One μl of uncentrifuged urine specimens were
aseptically inoculated, using standard loops, onto sheep blood
agar (SBA) plates containing 6% blood and cysteine lactose
electrolyte deficient (CLED) gar plates. The plates were
incubated aerobically for 24 to 48 hours at 37°C. The plates
were read at the end of the incubation period. Colony counts
equal to or more than 105/ml was considered as significant
growth.
Antibiotic sensitivity test
Antibiotic susceptibility testing was carried out using the
Kirby-Bauer disc diffusion technique on Muller-Hinton agar
and commercial antibiotic discs (Oxoid, United Kingdom)
were used for antimicrobial testing. 14 The antibiotic discs
used were: Ampicillin (10 μg), Naldixic Acid (30 μg),
Nitrofurantoin (300mg), Cephalexin (30 μg), Gentamicin (10
μg), Trimethoprim-Sulphamethoxazole (1.25/ 23.75 μg) and
ciprofloxacin (5 μg). The antibiotic disc impregnated culture
plates were incubated at 37°C overnight. The diameter of the
zone of inhibition was measured and recorded as resistant or
susceptible. For the test of proteinuria, the end of the reagent
strip was dipped in the fresh urine for approximately 1
second and shaken off by tapping the strip on the side of the
container. After 30 to 60 seconds the test strip was compared
with the color scale (color range from yellow for “negative”
and through yellow-green and green blue for “positive”). For
microscopy about 10 ml of well-mixed urine sample was
centrifuged at 2000xg for 5 minutes. A drop of the deposit
was examined microscopically at 40x for the presence of pus
cells, red blood cells, epithelial cells, casts and crystals.
Data Analysis
The Sigma plot version 12 for windows was used for data
analysis. The results are expressed as mean value ± standard
deviation. Chi-square test was used for comparison between
groups. A two-tailed p-value less than 0.05 was considered
statistically significant.
RESULTS
The total number of participants who finished the study was
392. The mean age of the participants was 29.76 ± 6.71(range,
21-37 years). Of the 392 urine specimens processed, 102
(26.0%) showed significant bacteriuria. Thus the prevalence
of different types of causative organism of significant
bacteriuria was 26.0%. The frequency of the microorganisms
isolated is shown in Table 1. The commonest organism
causing bacteriuria was Escherichia coli. The sensitivity
pattern of the isolated organisms revealed that all were
sensitive to ciprofloxacin and gentamicin at very high
percentage (Table 2). The organisms showed resistance to
currently preferred urinary antibiotics and
chemotherapeutic agents like co-trimoxazole, norfloxacin,
and cephalexin (Table 2). 200 (51.5%) women had more than
5 pus cells in urine specimens from which 50 (12.75%) had
positive cultures. Women with higher number of pus cells in
urine specimen had significantly higher asymptomatic
bacteriuria (p= o.ooo, p < 0.0001).
Table 1: Microorganisms isolated in positive cultures
Isolates
Percentage
Escherichia coli
70.8
Klebsiella
16.7
Group B Streptococcus
8.3
Proteus mirabilis
4.2
Table 2: Antimicrobial susceptibility pattern of organisms causing
bacteriuria in pregnant women
Drugs
E. coli
Klebsiella
Group B
Streptococcus
Proteus
Ciprofloxacin
89.2
87.1
95
95
Gentamicin
89.6
88.1
69.7
65
Ampicillin
50.3
0
35.1
10
Nitrofurantoin
65.1
73.1
82.2
0
Cephalexin
28.0
19.2
17.7
15.4
Nalidixic acid
68
42.5
48.6
31.1
Co-trimoxazole
12.4
29.4
0
2
DISCUSSION
Urinary tract infections are remarkably common in women.
Some 20% women in the age range 20-65 years suffer from
at least one attack per year, 50% develop a urinary tract
infection within their life time. 16 Not surprisingly infections
of the urinary tract are the most common bacterial infections
encountered during pregnancy. These can be both
symptomatic and asymptomatic. Asymptomatic bacteriuria
during pregnancy is a common and important medical
condition, which will result in overt renal infections such as
pyelonephirits if not detected and treated. 17 Smaill et al, 18
showed that on an average treating seven pregnant women
with asymptomatic bacteriuria results in prevention of one
episode of pyelonephirits. Ten percent of pregnant women
attended in an antenatal clinic had symptomatic urinary tract
infections 4. In another study by Khatun et al. (1985), 6 it was
found that 30% of clinically healthy pregnant women had
asymptomatic bacteriuria. Findings of the present community
based study indicate that the asymptomatic bacteriuria in
pregnancy is a major health problem in Srinagar city.
Observed from this study that E. Coli was the commonest
pathogen responsible for bacteriuria. It is consistent with the
findings of Rahman et al. (1990), 13, 14 and Ahmed et al.
(1996). 10, 12 Like the other studies, 16, 17, 18 the findings of our
study also indicate that ciprofloxacin is highly effective. The
most effective in-vitro agents were found to be gentamicin
among the injectables and ciprofloxacin among the orally
administered ones. Other useful oral antibiotics were
nitrofurantoin and nalidixic acid. The organisms showed
resistance to currently prefer urinary antibiotics and
chemotherapeutic agents like co-trimoxazole and cephalexin.
This fact indicates that urinary pathogens became resistant
day by day to the commonly used antibiotics in Nepal. This
may be due to wide spread and indiscriminate use of the
drugs. There are many studies,16 that link so many pregnancy
complications like hypertensive disorders in pregnancy, low
birth weight, premature with symptomatic bacteriuria.

Bijay Aryal et al. IRJP 2012, 3 (11)
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Moreover, for the last two decades, asymptomatic bacteriuria
has also been identified as a risk factor of similar pregnancy
complications. 16 The results of the present study also agree
with these findings. The association between asymptomatic
bacteriuria and prematurity is established. 7, 8, 12 But the
mechanism is not well defined yet. Several investigators have
observed a high incidence of pyelonephritis in bacteriuric
pregnant mothers. 7, 8
In conclusion, screening for bacteriuria in pregnancy and
proper treatment must be considered as an essential part of
antenatal care in Nepalese community. A negative test for
pyuria is not a reliable indicator of the absence of
asymptomatic bacteriuria in pregnant women. Thus, all urine
specimens, regardless of leukocyte count, should be sent for
culture and sensitivity.
ACKNOWLEDGEMENT
The authors would like to thank Chitwan Medical College
Teaching Hospital for providing research facilities.
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