CHAPTER ONE
1.0   INTRODUCTION
1.1   URINARY TRACT INFECTIONS
Urinary Tract Infections (UTIs) are associated with the 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 the 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 the 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).