INVESTIGATION OF UTI IN PREGNANCY
ABSTRACT
Urinary tract infection (UTI) occurs frequently in pregnancy with a large number of infections being asymptomatic. This study was therefore conceived to determine the incidence of asymptomatic bacteriuria in pregnant women in Sabon- Gari LGA – Zaria, Nigeria using questionnaire as well as isolate and characterize any bacteria present in urine of apparently healthy pregnant women and to determine the antibiogram of such isolates. Urine samples from two hundred and fifty (250) apparently healthy pregnant women, who were attending ante-natal clinics in Sabon-Gari Local Government Area Zaria, Nigeria, were interviewed and urine samples were collected for isolation of any possible bacteria present. Isolation was done by culturing on standard laboratory media and identification of isolates were subsequently done using standard biochemical tests and confirmed using API (bioMerieux, USA) rapid kits. The antibiogram of the isolates were determined using selected antibiotics and using disc agar diffusion technique. Plasmid isolation using gel electrophoresis was carried out on selected isolates that were multiple antibiotics resistant. Molecular characterization using multiplex Polymerase Chain Reaction (PCR) was carried out to detect nature of resistance in the resistant isolates. Primers such as SHV, OXA, TEM, aaclla, gyrA and gyrB, that codes for resistant genes for aminoglycosides, penicillins, cephalosporins and fluoroquinolones were used. Tests were also carried out to detect the production of β-lactamase and extended spectrum β-lactamase enzymes in the resistant isolates. A total of 146 (58.4%) had levels of bacteria indicative of asymptomatic bacteriuria. Higher incidences were found among 21-30 years age group 92 (36.8%), those in their second trimester 77 (30.8%) and among third parity (number of pregnancy) patients. Standard biochemical tests revealed the presence of 197 isolates comprising of Staphylococcus spp 50 (20.0%), Klebsiella spp 49 (19.6%), Proteus spp 46 (18.4%), Escherichia spp 33 (13.2%), Pseudomonas spp 18 (7.2%) and Streptococcus spp 1 (0.4%). Using API Staph kits a total of 20 Staphylococcus species made up of Staph. aureus, Staph. lentus, Staph. xylosus, Staph. cohnii, Staph. auriculous, Staph. epidermidis, Staph. heamolyticus and Micrococcus spp 4(10.3%) were identified. The API 20E kit revealed the presence of 22 Enterobacteriaceae made up of Escherichia coli, Enterobacter cloacae, Citrobacter freundii, Citrobacter braakii, Providencia rettgreri, Klebsiella pneumonia while API 20NE kit revealed the presence of Pseudomonas aeruginosa, Aeromonas aerohydrophila/caviae, Pseudomonas leutola, Burkholderia pseudomallei. The susceptibility profile of the isolates to selected antibiotics shows that all the isolates were resistant to the β-lactam antibiotics (Ampicillin (AMP) and Methicillin (MET) but relatively sensitive to Ofloxacin (87.5%), Gentamicin (71.4%), Nitrofurantoin (69.4%), and Ciprofloxacin (87.0%). A large number of the isolates were multiple antibiotics resistant. Some of the isolates were β-lactamase and Extended Spectrum β-lactamases (ESBLs) producers. Molecular characterization of the plasmid DNA showed the presence of resistant gene determinants that code for resistance to ESBLs.
CHAPTER ONE
INTRODUCTION
1.1 URINARY TRACT INFECTIONS
Urinary Tract Infections (UTIs) are associated with multiplication of organisms in the urinary tract. UTI defined as the microbial invasion of any of the tissues of the urinary tract extending from the renal cortex to the urethral meatus (DelzellandLefevre, 2000). The urinary tract includes the organs that collect and store urine and release it from the body which include: kidneys, ureters, bladder, urethra and accessory structures. Urine formed in the kidney is a sterile fluid that serves as a good culture medium for proliferation of bacteria (Omonigho et al., 2001). UTI is evident by the presence of 105 microorganisms or of a single strain of bacterium per ml in two consecutive midstream samples of urine (Davidson et al.,1989). UTI could be described based on the part of the tract affected, for upper tract it is called Pyelonephritis and the lower part, cystitis (Stamm, 1998).
Urinary tract infections are the second most common type of infection in the body and account for around 8.1 million visits to health care providers each year (Onyemelukwe et al., 2003). Over 50% of all women will experience at least one UTI during their lifetime, with 20-30% experiencing recurrent UTI (Brook et al., 2001). Women are more likely to develop UTIs than men, due to anatomical differences; the urethra is shorter in women than in men, and it is closer to the anus, making it more likely that bacteria are transferred to the bladder. With each UTI, the risk that a woman or man will have another UTI increases. Pregnant women are not more likely to develop a UTI than other women, but if one does occur in a pregnant woman then it is more likely to travel up to the kidneys due to anatomical changes affecting the urinary tract in pregnancy (Dimetry et al., 2007). As a UTI in pregnancy can prove dangerous for both maternal and infant health, most pregnant women are tested for bacteriuria, even if asymptomatic, and treated with prophylactic antibiotics. Most UTIs are not serious, but some can lead to serious problems, particularly with upper urinary tract infections. Recurrent or long-lasting kidney infections (chronic) can cause permanent damage, and some sudden kidney infections (acute) can be life-threatening, particularly if septicemia (bacteria entering the bloodstream) occurs.They can also increase the risk of women delivering low birth weight or premature infants (Dimetry et al., 2007).
UTI has been reported among 20% of the pregnant women and it is the most common cause of admission in obstetrical wards (Bacak et al., 2005). Anatomically UTI can be classified into lower urinary tract infection involving the bladder and urethra and upper urinary tract infection involving the kidney, pelvis, and ureter. The majority of the UTI occur due to ascending infection (Orenstein and Wong, 1999; Delzell and Lefevre, 2000). Three common clinical manifestations of UTIs in pregnancy are: asymptomatic bacteriuria, acute cystitis and acute pyelonephritis (Loh and Silvalingam, 2007).
UTI is defined as the presence of at least 100,000 organisms per milliliter of urine in an asymptomatic patient, or as more than 100 organisms/mL of urine with accompanying pyuria (>5 WBCs/mL) in a symptomatic patient. Particularly in asymptomatic patients, a diagnosis of UTI should be supported by a positive culture for auropathogen(Emilie et al., 2011). Untreated asymptomatic bacteriuria is a risk factor for acute cystitis (40%) and pyelonephritis (25-30%) in pregnancy. These cases account for 70% of all cases of symptomatic UTI among unscreened pregnant women (Emilie et al., 2011). Symptomatic and asymptomatic bacteriuria have been reported among 17.9% and 13.0% pregnant women, respectively (Masinde et al., 2009).
Pregnancy increases the risk of UTI. At around 6th week of pregnancy, due to the physiological changes of pregnancy the ureters begin to dilate. This is also known as “hydronephrosis of pregnancy”, which peaks at 22-26 weeks and continues to persist until delivery. Both progesterone and estrogens levels increase during pregnancy and these will lead to decreased ureteral and bladder tone. Increased plasma volume during pregnancy leads to decrease urine concentration and increased bladder volume. The combination of all these factors lead to urinary stasis and uretero-vesical reflux (Delzell and Lefevre, 2000).Additionally, theapparent reduction in immunity of pregnant women appears toencourage the growth of both commensal and non-commensalmicroorganisms (Scott et al., 1999). The physiological increase in plasmavolume during pregnancy decreases urine concentration and upto 70% pregnant women develop glucosurea, whichencourages bacterial growth in the urine (Patterson and Andrriole, 1987; Lucas and Cunningham, 1993).
Female gender itself is a risk factor because of short urethra, its proximity to vagina and anus and inability of women to empty their bladder completely. High incidence is seen in lower socioeconomic group (Wesley, 2002). Sexual activity and certain contraceptive methods are also said to increase the risk (Bandyopadhyay et al., 2005) The anatomical relationship of female’s urethra and the vagina makes it liable to trauma during sexual intercourse as well as bacteria been massaged up the urethra into the bladder during pregnancy/child birth (Arthur et al., 1975; Duerden et al., 1990). Abnormalities of urinary tract or stones, diabetes mellitus, immunosupression and past history of UTI tend to increase the risk (Patterson and Andriole, 1997).
Urinary tract infection during pregnancy contributes significantly to maternal and perinatal morbidity (Akerele et al., 2002). Abortion, small birth size, maternal anemia, hypertension, preterm labour, phlebitis, thrombosis and chronic pyelonephritis are related to urinary tract infection during pregnancy (Akerele et al., 2002; Onuh et al., 2006). coli remains the predominant organism implicated in urinary tract infection in pregnancy, though recent reports show changes in pattern of the infection (Onuh et al., 2006). Recent studies in Nigeria show an increasing involvement of Klebsiella Spp. Staphylococcus aureus, Proteus spp., and Pseudomonas spp. in urinary tract infection in pregnancy (Abdul andOnile, 2001). Studies have also shown that treatment of bacteriuria during pregnancy reduces the incidence of these complications (Patterson and Andriole, 1987) and lowers the long-term risk of sequelae following asymptomatic bacteriuria (Barr et al., 1985).
1.2 OBJECTIVES OF THE RESEARCH
This objectives of this research are to;
i. Investigate the Urinary tract infections in pregnancy
ii. Investigate Urinary tract infections in relation to age distributions of pregnant women.
iii. Determine percentage of occurrence and distribution of bacterial pathogens in Urinary tract infections among pregnant women
1.3 JUSTIFICATION
Urinary tract infections typically occur when bacteria enter the urinary tract through the urethra and begin to multiply in the bladder. Although the urinary system is designed to keep out such microscopic invaders, these defenses sometimes fail. When that happens, bacteria may take hold and grow into a full-blown infection in the urinary tract. Antibiotic sensitivity can be tested with urine culture, making it useful in the selection of antibiotic treatment.