Urinary tract infections (UTIs) represent the commonest genitourinary disease in children, and are the second commonest infection, which affects them¹. Urinary tract infections in children are particularly important because their occurrence may be associated with some congenital abnormality of the urinary tract or an error in management. If not corrected, these may lead to recurrent infections causing damage to the urinary tract^1,2.
Urinary tract infections occur in as many as 5 percent of girls and 1 to 2 percent of boys.³ The incidence of UTI in infants ranges from approximately 0.1 to 1.0 percent in all newborn infants to as high as 10 percent in low-birth-weight infants.⁴ Infection of the urinary tract before age one occurs more frequently in boys than in girls.⁴ After age one, both bacteriuria and UTI are more common in girls.
In preschool-age children, the prevalence of asymptomatic infections diagnosed by suprapubic aspiration in girls is 0.8 percent, compared with 0.2 percent in boys.⁵ In the school-age group, the incidence of bacteriuria among girls is 30 times that among boys (1.2 versus 0.04 percent).⁶
Approximately half of girls and two thirds of boys experience high fever with these infections. In fact, UTIs have recently been described as one of the most common serious bacterial illnesses among febrile infants and young children with a reported prevalence ranging from 4.1% to 7.5%. These figures suggest that the true frequency of UTIs in children have been underestimated in the past⁷. It is more common in the uncircumcised male infant.
Infection may occur at many places along the genitourinary tract: urethra, bladder, ureter, renal pelvis, or renal parenchyma.1,8 It is assumed that the short urethra in girls predisposes them to ascending infection, because, for example Escherichia coli serotypes from bowel flora are the same as those that infect the urinary tract. However, factors other than the proximity of gut flora to the short urethra are likely because the female to male ratio in urinary tract infection varies directly with age 1,9.
Most infections are due to colonic bacteria and are due to invasion up the urethra. Of these, E.coli is by far the most commonly isolated organism, being responsible for approximately 80% of UTIs⁷. E.coli has recognized virulence factors which aid in the persistence of bacteria in the urinary tract and induce inflammation. Such factors include the presence of pili or fimbriae, K antigen in bacterial capsule, haemolysin and colicin production and the ability to acquire iron etc⁷.
Microbiologically, urinary tract infection exists when pathogenic microorganisms are detected in the urinary tract ^6,10. The infection is considered significant and requires treatment when more than 105 microorganisms per milliliter of urine are present in a properly collected specimen.^6,10 Gram-negative bacteria such as E. coli, Proteus spp., Klebsiella spp., Enterobacter spp., Serratia spp. and Pseudomonas spp. are usually detected in recurrent infections, especially in association with stones, obstruction, urologic manipulation and nosocomial catheter-associated infections. ^2,6,11
The aim of this study was to obtain data about different types of organisms and their respective frequencies causing urinary tract infection in children.

The sample of this study was conducted in the Department of Pediatrics, Princess Haya hospital (Aqaba- south of Jordan).
After institutional ethical committee clearance and written informed consent, urinary specimens were collected from one hundred patients, ages 0-15 years of age, suffering from urinary tract infections, who were either inpatients or outpatients.
The majority of patients were self-referrals, while others were referred by general practitioners. They presented with a variety of complaints and if a urinary tract infection was suspected, a urine culture and colony count was performed, combined with a full report of urine to establish the diagnosis.

Of the one hundred children, 41% were males and 59% were females.

A detailed history was taken and complete clinical examination was carried out for each case of urinary tract infection. Every patient had urine microscopy, ultrasound of kidneys and urinary bladder, urinary colony count and urine culture investigations.

A diagnosis of a UTI was made when the colony count was over 105 organisms/ml and microscopic finding of more than 5 white blood cells per high power field on urine microscopy. A patient with UTI may not have leucocytes in the urine; leucocytes may be found in urine in the absence of UTI eg. Acute glomerulonephritis. The amount of leucocytes found in urine would be determined by the speed and time of centrifugation and the depth from which the deposit is taken. In an uncentrifuged sample of urine the detection of >10 leucocytes per mm³ is thought to be significant¹².
In Neonates the urine was collected through supra pubic approach. In uncooperative and moribund patients the urine was also collected through the supra pubic puncture or urinary catheterization. In infants and older children the urine was collected in urine collecting bag or sterilized container, after washing the genital region with soap and water. Mid stream, clean catch, early morning specimens were collected in a sterilised container. Instructions were given to transfer the urine from the bag to the culture bottle soon after collection. All urine cultures at the time of initial diagnosis were collected after stopping antibiotics for at least 72 hours. Urine sample was delivered to the laboratory within 1 hour of collection. Urine specimens that were not examined within six hours of collection were stored at +4 °C, because at 0-4 °C the bacterial count will remain unchanged for 24-48 hours ¹³. About 5ml of urine was centrifuged, the super-natants tipped off and the deposit resuspended in the urine that drained back (about 0.1ml). A wet film of the suspension was examined microscopically with the ´40 and the ´100 objectives. More than two or three white cells per field with the ´100 objective were regarded as abnormal. The presence of any red cells was regarded as abnormal ¹³.

For bacteriological examination, the urine samples were cultured in 5% sheep blood agar and MacConkey's media. Inoculation was done with the help of a 0.001ml caliber loop. All the sample plates were incubated for 48 hrs at 37oC in 5-10% carbon dioxide for anaerobic growth. Bacterial identification was done by examination of the overnight culture with a hand lens and also by a standard biochemical and sensitivity test to antibiotics using a disk diffusion method (Kirby-Bauer) ¹³. All cultures were performed in one laboratory and by a consultant microbiologist. If the growth revealed more than one type of organism the culture was repeated. Colony counts of <104 organisms/ml were disregarded; counts between 104 to 105 organisms/ml were repeated.

There were 41(41%) boys and 59(59%) girls giving a total of 100 patients. The data shows that the majority of bacterial urinary infections were in the 1-5 year-old age group (49%) and the lowest in the 0-1 year-old age group (5%); the number of patients was less in the neonatal period and the cases increased with increasing age and declined after thirteen years of age till fifteen years. There were more boys in the under 1 year age group and more girls in the older age group. Pathogens isolated in different age groups are given in Table I.
The pathogens isolated at initial diagnosis are given in Table II. E.coli accounted for the vast majority of infections (72%), while Klebsiella pneumonia was isolated in 14%, Proteus species (9%), Staphylococcus (4%) and Pseudomonas in (1%).

Urinary tract infection in children is a significant source of morbidity. It is generally agreed that children with UTI require further investigation and continuing urinary surveillance to minimize future complications. ¹⁴

Although the drug treatment of urinary tract infection is simple, the disease is still largely misdiagnosed and mismanaged. Studies have shown that the early phase of tissue invasion by micro-organisms is the critical determinant in the pathogenesis of kidney lesions following urinary tract infection and therefore early diagnosis with prompt and effective antimicrobial therapy for acute renal infection will prevent or significantly inhibit the development of renal damage. ¹⁵

The only reliable method for precise diagnosis of UTI is the demonstration of bacteria by appropriate culture methods. Bacterial counts greater than 105 organisms / ml in urine samples and pure growth of a single type of organism is found in the majority of cases. Escherichia coli is the commonest organism infecting the urinary tract. Others include Klebsiella sp., Enterobacter sp., Serratia sp., Pseudomonas aeruginosa and other Pseudomonas sp., Enterococci, Staph.saprophytics, S.aureus, S.epidermidis, Acinetobacter sp., B haemolytic streptococci group B&D, Candida albicans, Salmonella sp., and Mycobacteria.

In our study the organisms infecting the urinary tract were E.coli (72%), Klebsiella pneumonia (14%), Proteus species (9%), Staphylococcus (4%), Pseudomonas (1%). These results are similar to many recent published articles.^{16, 17}

Several studies in children above one year of age till fifteen years reported female predominance, with a variable ratio ranging from 6:1 to 1.33:1, depending upon the different sample size, and difference in age groups being studied.^16-20
In the present study Most of the infections were observed in the female patients with an overall male to female ratio of 1:1.4. Males outnumbered females during the first year of life with a ratio of 1.5:1; this is in full agreement with other studies.^21-24

The diagnosis of UTI in young children is important as it is a marker for urinary tract abnormalities.

A child with a suspected UTI should have a urine culture and colony count performed in order to identify organisms for confirmation of diagnosis and recommend prompt treatment to reduce UTI related morbidity and mortality in children.

Table 1. Pathogens isolated in different age groups

Table II: Pathogens isolated at initial diagnosis

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