ABSTRACT
Urinary tract infection (UTI) constitutes a major health problem in pregnant women. It is more common in this group due to the anatomical and physiological changes that occur during pregnancy. This study was undertaken to characterize antibiotic resistant Escherichia coli isolated from pregnant women in Umuahia. A total of 250 mid stream urine samples from pregnant women in different trimesters were analyzed and cultured on cystein lactose electrolyte deficient (CLED) agar and MacConkey agar. Isolation and identification of Escherichia coli was done by Gram staining and biochemical analysis. Antibiotic susceptibility test was done by Kirby-Bauer disc diffusion method. The prevalence rate of UTI in the study population was observed to be 32%. The prevalence of Escherichia coli among positive isolates was (59) 73.7%. Majority (117) of those with Escherichia coli present in their urine presented at the second trimester (52.5%) while 23 (39.9%) presented at the third. Only 17 (6.8%) of the studied subjects were in their first trimester and 5 (8.4%) of those had Escherichia coli present in their urine. Among all those that had Escherichia coli, 64.4% of them were aged 25-34 years. However, there was no significant relationship (P>0.05) between age or trimester and presence of Escherichia coli, which signify that bacteriuria is independent on age and trimester in the study population. The relationship between those that had previous case of UTI and presently had Escherichia coli was found to be statistically significant at (P<0.05). Escherichia coli isolated from the pregnant women showed 100% resistance to amoxicillin and tetracycline. Imipenem and gentamicin should be the antibiotic of choice for treating UTI in the study area because they showed sensitivity of over 70%. Thirty, 30 (50.8%) of the Escherichia coli isolates showed potential to produce biofilm. Extended spectrum beta-lactamase (ESBL) production among Escherichia coli isolates was found to be 12 (20.3%) while 2 (3.4%) isolates produced chromosomal ambler C (iAmpC). Out of 10 highly resistant Escherichia coli isolates, 4 had plasmid. Screening of pregnant women for possible UTI at early stage of pregnancy should be considered an essential care in the study environment to avoid complications in pregnancy.
TABLE OF CONTENTS
Title Page i
Declaration ii
Dedication
iii
Certification iv
Acknowledgement v
Table of Content vi
List of Tables viii
List of
Plate ix
Abstract x
CHAPTER 1: INTRODUCTION 1
1.1 Background of Study 1
1.2 Problem Statement 3
1.3 Significance of Study 4
1.4 Justification 4
1.5 Scope of Study 4
1.6 Aim and Objectives 5
1.6.1 Aim 5
1.6.2
Specific objectives 5
CHAPTER
2: LITERATURE REVIEW 6
2.1 Escherichia coli 6
2.2 Urinary
Tract Infections 7
2.2.1 Causes and risk factors associated with urinary tract infections 8
2.2.2 Diagnosis of urinary tract infections 9
2.2.3
Specimen collection and
processing 9
2.2.4 Epidemiology of urinary
tract infections 10
2.2.5
Pathogenesis of uropathogenic Escherichia coli 10
2.2.6 Symptoms of urinary tract infections 12
2.3 Urinary
Tract Infection and Pregnancy 12
2.4 Vaginal
Ecology and UTI 13
2.5 Bacteriuria 14
2.6 Antibiotic
Resistance 15
2.6.1 Causes of antibiotic resistance 16
2.6.2 Prevention of antibiotic resistance 17
2.6.3 Mechanisms of antibiotic resistance 18
CHAPTER 3: MATERIALS AND
METHODS 20
3.1 Collection
of Specimen 20
3.2 Microscopy 20
3.3 Preparation
of Culture Media 20
3.4 Isolation,
Characterization and Identification of Isolates 21
3.4.1 Gram staining 21
3.4.2 Biochemical
tests 22
3.4.2.1 Indole test 22
3.4.2.2 Oxidase test 22
3.4.2.3 Kligler iron agar reaction 22
3.4.2.4 Methyl red-Voges Proskauer
test 23
3.5 Antibiotic
Susceptibility Testing 23
3.6 ESBL
Producers Screening and Confirmation 24
3.7 Biofilm
Production 24
3.8 Detection
of AMPC 24
3.9 Plasmid
Analysis 25
3.10
Statistical Analysis 26
CHAPTER 4: RESULTS AND
DISCUSSION 27
4.1 Results 27
4.2 Discussion 40
CHAPTER 5: CONCLUSION
AND RECOMMENDATION 44
5.1 Conclusion 44
5.2 Recommendation 44
References 46
Appendix 55
LIST OF TABLES
4.1:
Frequency of occurrence of bacterial
isolates 28
4.2:
Distribution and frequency of Escherichia coli isolates per trimester
of
pregnancy 29
4.3:
Age Distribution and frequency of Escherichia coli isolated from study 31
4:
Antibiotic susceptibility pattern
of Escherichia coli isolates 32
4.5:
Biofilm, extended spectrum
Beta-lactamase (ESBL) and chromosomal
ambler C (iAmpC) production among
isolates 33
4.6:
Presence of plasmid among Escherichia coli isolates 34
4.7: Distribution
of cured plasmids 37
4.8: Frequency of previous
case of UTI and its relationship with presence of
Escherichia coli in urine 38
4.9: Cumulative responses of 250 women to
different signs and symptoms of
UTI and it’s relationship with Escherichia coli 39
LIST OF PLATE
4.1: Plasmid
analysis of E. coli isolates showing
presence of plasmid 36
CHAPTER 1
INTRODUCTION
1.1 BACKGROUND OF STUDY
Pregnancy
causes numerous changes in a woman’s body. These changes along with an already
short urethra which
allow bacteria quick access to the bladder
and difficulty with hygiene due to a distended pregnant belly increase the
frequency of urinary tract infection (UTI) in pregnant women. Indeed, UTI is
among the most common bacterial infections that complicate pregnancy (Johnson
and Kim, 2015).
UTI
refer to the presence of microbial pathogens within the urinary tract and it is
usually classified by the infection site: bladder (cystitis), kidney
(pyelonephritis) or urethra (bacteriuria) (Gonzalez and Schaeffer, 1999). UTI
has been defined as the commonest bacterial infection (Demilie et al., 2012; Parveen et al., 2011). It is regarded as the
most common hospital acquired infection (Koffour et al., 2012; Kolawale et al.,
2009). Human urine can support bacterial growth due to its favourable chemical composition
(Asscher and Sussman, 1969). According to Awaness et al., (2000), UTI affects all age group but are relatively common
in females as compared to males due to the following reasons; pregnancy, urethra
in women is shorter, women tend not to empty their bladder as completely as
men, bacteria enter the bladder during intercourse. Also in women, the lower
third of the urethra is continually contaminated with pathogens from the vagina
and the rectum and there is absence of prostatic secretion which is believed to
contain bactericidal substance.
Bacteriuria during pregnancy may be
classified as asymptomatic bacteriuria, infections of the lower urinary tract
(cystitis), or infections of the upper urinary tract (pyelonephritis). Lower
tract bacteriuria is associated with an increased risk of developing
pyelonephritis in pregnancy, which is itself associated with adverse maternal
and fetal outcomes (Glaser and Schaeffer, 2015). UTI is an independent risk factor for renal carcinoma
and bladder cancer. It is also a risk factor for premature delivery, foetal
loss and kidney infections (Linhares et
al., 2013). In
pregnancy, complications such as hypertensive disease of pregnancy, anemia,
chronic renal failure, premature delivery and foetal mortality may occur as a
result of UTI (Delzell and Lefevre, 2000; Foxman, 2002). Some symptoms of UTIs
include; pain or burning sensation during urination, the need to urinate more
often than usual, blood or pus in urine, cramps or pain in the lower abdomen,
strong smelling urine, pain during sexual intercourse, nausea, vomiting and
malaise (Lane and Takhar, 2011). Gilstrap and Ramin (2001) recommend that all pregnant women
be screened for the presence of bacteriuria at their first prenatal visit. This
is because failure to treat bacteriuria during pregnancy may result in as many
as 25% of women experiencing acute pyelonephritis, which has been implicated in
preterm labor, transient renal failure, acute respiratory distress syndrome (ARDS),
sepsis and shock, and hematologic abnormalities.
Ordinarily,
UTIs are caused by a variety of Gram-negative and Gram-positive bacteria. The
Gram-positive bacteria are Staphylococcus
spp, Streptococcus spp and Enterococcus spp. The Gram-negative
bacteria are Escherichia spp, Klebsiella spp, Enterobacter spp, Citrobacter
spp, Proteus spp, Serratia spp, Salmonella spp and Pseudomonas
spp (Ouno et al., 2013). Among
these, 80-90% of UTI is caused by Escherichia
coli (E. coli).
The
World Health Organization (WHO) defines antimicrobial resistance as a
microorganism’s resistance to an antimicrobial drug that was once able to treat
an infection caused by that microorganism (WHO, 2014a). As a result, standard
treatments become ineffective, infections persist and may spread. Resistance is a property of the microbe, not
a person or other organism infected by a microbe. Certain features such as production
of extended-spectrum beta-lactamases (ESBLs), presence of plasmid, generation
of biofilm, can confer resistance to an organism. ESBLs are beta-lactamases
equipped for giving bacterial protection from the penicillin, cephalosporins
(first, second and third ages) and aztreonam, by hydrolysis of these
anti-infection agents. These anti-toxins are hindered by lactamase inhibitors,
for example, clavulanic acid. As of late, there has been worry that a few
strains of E. coli can create ESBL.
These enzymes are significant because when they are produced by bacteria, they
can make the bacteria resistant to certain commonly used antibiotic medicines. This
implies that organisms that produce them can keep on duplicating, causing
increasingly serious contamination and ending up progressively hard to treat.
All
bacteriuria in pregnancy need to be dealt with and antimicrobial decision in
pregnancy need to reflect wellbeing for both the mother and the foetus (Glaser
and Schaeffer, 2015). Pregnant women with urinary tract contaminations ought to
be followed up firmly after treatment on the grounds that up to one third will
encounter a repeat.
1.2 PROBLEM STATEMENT
UTI
in pregnancy contributes significantly to maternal and perinatal morbidity and
mortality. This, coupled with a steady rise in drug resistant pathogens
attributed to the excessive or inappropriate use of antimicrobial therapy and
the indiscriminate use of broad-spectrum antibiotics, indicates the need for a
more proactive approach in the use of antibiotics especially for pregnant
women. Hence, an attempt to characterize E.
coli a major cause of UTI.
1.3 SIGNIFICANCE OF STUDY
This study sets out to analyse and characterize
antibiotic resistant pathogens from pregnant women in Umuahia, with interest in
E. coli known to be the most common
cause of UTI. It’s findings will provide insight into the drug susceptibility
pattern of E. coli associated with
UTI in the study area. As the safety of mother and child during pregnancy
continues to be an issue of great concern to all across the globe, it is
expected that the findings of this research will guide physicians and
healthcare providers who attend to these women in drug prescription in the case
of UTI even before culture and sensitivity is carried out.
1.4 JUSTIFICATION
Bacterial infection during pregnancy remains a
relevant complication to healthcare even in developed countries. Due to
widespread multi-resistance to antibiotics coupled with the physiologic changes
associated with pregnancy, these women cannot use any type of drug even after
culture and sensitivity. As a result of this, treatment options are becoming
very narrow. Hence to ensure appropriate therapy, current knowledge of E. coli which is one of the most common
organisms involved in UTI in pregnancy and the antibiotic susceptibility
pattern is very important.
1.5 SCOPE OF STUDY
This
study will characterize antibiotic resistant E. coli isolates from pregnant women in Umuahia. Urine specimen of
these women will be analysed for significant bacterial growth.
1.6 AIM
AND OBJECTIVES
1.6.1 Aim
The
aim of this research is to characterize antibiotic resistant E. coli isolated from urine samples of
pregnant women in Umuahia and also to establish baseline data from antibiotic
susceptibility tests that could guide prescriptions in our health facilities.
1.6.2
Specific
objectives
1. To
determine prevalence of Escherichia coli
isolates causing UTI in pregnant women in Umuahia.
2. To
determine the resistance pattern of Escherichia
coli from UTI in pregnant women to various antimicrobials.
3. To
determine the potential to produce biofilm in the isolates.
4. To
determine the presence of ESBL production in the isolates.
5. To
carry out plasmid analysis on highly resistant isolates.
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