|Year : 2012 | Volume
| Issue : 1 | Page : 25-29
Epidemiology of urinary tract infection in neonatal intensive care unit: A single center study in Egypt
Doaa Mohammed Youssef1, Hanaa Abd Elfateh1, Randa Sedeek2, Sherif Seleem2
1 Department of Pediatric, Zagazig University Hospital, Cairo, Egypt
2 Department of Microbiology & Immunology, Zagazig University Hospital, Cairo, Egypt
|Date of Web Publication||3-Dec-2012|
Doaa Mohammed Youssef
Department of Pediatric, Zagazig University, 310 Zahraa Naser City, Cairo 11231
Source of Support: None, Conflict of Interest: None
Introduction: The aim of this study is to describe the epidemiology of urinary tract infection (UTI) in newborn infants admitted to neonatal intensive care unit (NICU) of Zagazig University.
Patients and Methods: This study included 206 neonates admitted to the NICU in the period from 1/1/2010 to 1/6/2010. All neonates were subjected to detailed history taking, including prenatal history, natal history, and postnatal history, with stress on symptoms suggestive of UTI. We examined all neonates generally and locally, every case was subjected to urine analysis; suprapubic aspiration was done for all cases. "The diagnosis of UTI was established by the presence of at least 5 leukocytes per high power field." Urine culture, CBC (complete blood count), blood culture, and ultrasound scanning were also done for certain cases.
Results: We found 75 newborns with clinical findings suggesting UTI. We classified our neonates according to the presence of at least 5 leukocytes in urine per high power field into two groups: Group I (−ve cases) without UTI included 44 neonates (31 males and 13 females) and Group II (+ve cases) with UTI included 31 neonates (24 males and 7 females). There was no significant difference between Group I and Group II with regard to gender, age, weight, and consanguinity. The incidence of UTI in NICU was 15.05% (33/206), prevalence among suspected cases of UTI in NICU was 41.3% (33/75), and of the 39 neonates with sepsis 33 had UTI (79.5%). Of the positive cases, 77.4% were full-term neonates and 22.6% were preterm neonates. Of the 31 cases with positive urinary culture there were 18 cases (58.1%) showing Escherichia coli, and 13 cases (41.9%) were positive for Klebsiella.
Conclusion: This study has highlighted the need for routine urine analysis and culture, especially in high-risk newborns and to monitor the prevalence of UTI early in life. Also routine ultrasonographic screening should be done in all newborns with UTI to save the newborns and prevent the risk of complications, which may end in renal scarring and renal failure.
Keywords: Epidemiology, neonate, urinary tract infection
|How to cite this article:|
Youssef DM, Elfateh HA, Sedeek R, Seleem S. Epidemiology of urinary tract infection in neonatal intensive care unit: A single center study in Egypt. J Acad Med Sci 2012;2:25-9
|How to cite this URL:|
Youssef DM, Elfateh HA, Sedeek R, Seleem S. Epidemiology of urinary tract infection in neonatal intensive care unit: A single center study in Egypt. J Acad Med Sci [serial online] 2012 [cited 2020 Jun 7];2:25-9. Available from: http://www.e-jams.org/text.asp?2012/2/1/25/104012
| Introduction|| |
UTI is defined as significant bacteriuria irrespective of the site of infection in the urinary tract.  The exact rate of urinary tract infections (UTIs) in newborns is not known, but studies have found that from about 1 in 1000 to 1 in 100 in full-term infants, and up to 1 in 10 premature infants, will have a UTI during the first month of life. 
Most newborns and young infants present with symptoms of UTI and not asymptomatic bacteriuria. The higher incidence of UTI among male infants persists for the first 3-4 months of life, but thereafter the incidence and prevalence of UTI are considerably higher in females compared with males. 
Morbidity associated with pyelonephritis is characterized by systemic symptoms, such as fever, abdominal pain, vomiting, and dehydration. Bacteremia and clinical sepsis may occur. Children with pyelonephritis also may have cystitis. Long-term complications of pyelonephritis are hypertension and impaired end-stage renal disease. The voiding symptoms of cystitis are usually transient, clearing within 24-48 h of effective treatment. Long-term complications of UTI are caused by renal damage secondary to pyelonephritis. 
UTI are almost always ascending in origin and caused by bacteria in the periurethral flora and the distal urethra. These bacteria inhabit the distal gastrointestinal tract and colonize the perineal area. Escherichia coli usually cause a child's first infection (were responsible for more than 90% of cases of acute pyelonephritis in infants and children), but other gram-negative bacilli and enterococci may also cause infection. More rarely, the urinary tract may be colonized during systemic bacteremia (sepsis), this usually happens in infancy. 
Negative microscopic findings for bacteria do not rule out a UTI, nor do negative results of dipstick testing for nitrite and leukocyte esterase. 
The aim of this study was to describe the epidemiology of UTI in newborn infants admitted in neonatal intensive care unit (NICU) of Zagazig University and to assess the clinical characteristics and radioimaging studies.
| Patients and Methods|| |
This study included 206 (113 males and 93 females) neonates admitted to the NICU of Zagazig University Hospital in the period from 1/1/2010 to 1/6/2010. We found 75 (55 males and 20 females) with clinical findings suggesting UTI.
All neonates were subjected to full history taking, including prenatal history, natal history: gestational age (preterm < 37 weeks; full term > 37 weeks), mode of delivery, place of delivery, complications of delivery, birth weight, first cry, conditions at birth (birth trauma and congenital malformations), and postnatal history with stress on symptoms suggestive of UTI, including onset, course, and duration of the following:
(1) Failure to thrive, (2) fever whether acute or recurrent and high or low grade, (3) hypothermia, (4) vomiting whether related to feed or not, (5) urine retention, (6) jaundice, its onset, and duration, whether prolonged or not and accompanied by bad general condition and failure of suckling or other symptoms suggestive of septicemia, (7) abdominal mass and distention, (8) anuria, (9) irritability or lethargy, and (10) abnormalities in urine stream or flow of urine.
The age of the study cases (55 males and 20 females) ranged from 1 to 28 days; the mean age being 17.8. They included 60 full-term and 15 preterm babies. Their weight ranged from 1.300 to 4.000 kg.
We examined all neonates generally and locally. Every case was subjected to following investigations.
Suspected UTI is defined by the presence of at least 5 leukocytes in urine per high power field, whereas proved UTI is defined by positive culture.
Suprapubic aspiration was used for urine analysis and culture.
The neonates were classified accordingly into 2 groups:
We classified our neonates according to the presence of at least 5 leukocytes in urine per high power field into 2 groups;
The samples of urine were subjected to
- Group I (− ve cases) without UTI included 44 neonate (31 males and 13 females)
- Group II (+ ve cases) with UTI included 31 neonate (24 males and 7 females). 
(A) Macroscopic examination: color, aspect, (B) chemical examination by Multistexlo Baya® (Siemens Medical Solutions Diagnostics, Tarrytown, NY, USA)
Diagnostics and C- Microscopic examination of the sediment using 10× and 40× objectives.
On conventional media (cyteine lactose electrolyte deficient (CLED) and blood agar).
Plates were inspected for growth after 24 and 48 h. Positive cultures were stained by Gram stain and antimicrobial sensitivity was assessed using conventional plate method.
Using Sysmex Kx 21 from a Medical Diagnostics, Kobe city Japan.
Using both aerobic and anaerobic bottles samples were incubated in Bactalert® System Biomeviex. Marcy I΄etoile (a name of a city), France, results were considered as if no result obtained more than one week.
Because real-time ultrasound has been shown to be effective in visualizing the pediatric urinary tract, we used this study to determine whether it would be easy to screen newborns to diagnose renal abnormalities that might be helped by early treatment.
- Apparatus: High resolution real-time scanner, Sonolay 250 convex probe with a 3.75 and 5 MHz convex linear transducer. A 5 MHz transducer was used as it gives better resolution in newborns
- Method: No special preparation of the patient before the examination was done. The patients were examined in the supine position. Longitudinal scans of the kidney were obtained
- Interpretation of scanning: In scanning of the kidney, the following points were obtained: (A) Renal length and width and comparison of the sizes of both kidneys for detection of any discrepancy as in cases of unilateral atrophy or hypoplasia of one side, (B) renal parenchymal echogenicity, which is normally the same as that of the liver in case of new born infants, (C) any abdominal masses and their relationship to the kidney, and (D) assessment of the urinary bladder.
The data were tabulated and statistically analyzed using a computer and presentation of data was made using the Epi-INFO (2005) and SPSS version 10 software package.
Prevalence=number of +ve cases / number of population examined×100.
| Results|| |
This study included 206 (113 males and 93 females) neonates admitted to the NICU. We found 75 of them (55 males and 20 females) with clinical findings suggesting UTI.
There is no significant difference between Group I and Group II with regard to gender, age, weight, and consanguinity.
- Incidence of UTI in NICU was 15.05% (31/206)
- Prevalence among suspected cases of UTI in NICU was 41.3% (31/75)
- Of the 39 neonates with sepsis 31 have UTI (79.5%)
- Out of 60 full-term suspected to have UTI, 24 (40%) proved to have UTI, whereas of the 15 preterm, 7 (46.7%) proved to have UTI [Table 1]
|Table 1: The etiology of admission in studied neonates with clinical symptoms suggesting UTI|
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- Multiple congenital anomalies with respiratory distress was present in 3 cases (4%)
- There were no infants of diabetic mother
- Premature rupture of membranes was significantly high among Group II (+ve cases), whereas there was no significant difference between Group I and Group II with regard to mode of delivery and gestational age
- There is no significant difference between full-term and preterm neonates of both groups with regard to mode of delivery and premature rupture of membranes [Figure 1] and [Figure 2].
|Figure 1: Difference between Group I (−ve cases) and Group II (+ve cases) with regard to mode of delivery (NVD (normal vaginal delivery) and CS (caesarian section) and gestational age (preterm and fullterm)|
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|Figure 2: Causative organisms of urinary tract infection among studied neonates|
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- A 57.4% of Group II (+ve cases) presented with fever who are significantly higher than that of Group I, whereas the percentage of vomiting, diarrhea, abdominal distension, Irritability, Lethargy and Cyanosis are not significantly higher among Group II [Table 2].
| Discussion|| |
UTI is an important clinical problem in the neonatal period. Therefore, early diagnosis and proper treatment of UTI as early as possible is important.  UTI may have long-term consequences as they may produce kidney damage, which may lead later in life to hypertension, recurrent infections, and renal failure. 
In our study we found incidence of proven UTI in NICU was 15.05% (33/206) and prevalence among clinically suspected cases of UTI in NICU was 41.3% (33/75), this matches what Jurczak, and his colleagues,  found in 2007, that the UTI represents 14.9% in NU and NICU. But lower percentage than our result was recorded by Garcia and his group,  in 2002, where they found the incidence of UTI of 160 participants enrolled was 7.5%.
The difference of our prevalence of UTI from other studies may be explained by the selection of our neonates from NICU, where they are more susceptible to infection have high-risk factors as associated infectious diseases, use of broad-spectrum antibiotics, mechanical ventilation, parenteral nutrition, intravascular catheter, and prolonged stay in the intensive care unit; and the difference probably reflects variations in population characteristics and in predisposing factors.
In our study, there was a higher prevalence of UTI in males compared with females (64.3 % males and 35.7% females), and this is in agreement with similar studies, which found that males are more affected than females with UTI in the neonatal period. 
In our study, premature rupture of membranes is present in 5 cases out of 31 with UTI, that is, 35.7% of our findings coincided with that of Falcão's,  in 2000, who showed that there was premature rupture of membranes in 26.3% of cases with UTI, but in contrast to our result a study done by Garcia,  in 2002, found that the premature rupture of membranes was 0 in cases with UTI. This difference can be explained by their selection of only afebrile jaundiced neonates.
In the current study, we found the prevalence of UTI in clinically suspected full-term neonates in NICU is 40% (24/60), whereas it was 46.7% (7/15) in preterm neonates in NICU. This means that when we suspected UTI in preterm the positive cases were higher than that when we suspected UTI in full term, but a higher prevalence of UTI was present in full term compared with preterm neonates in absolute number of cases as the full term represented 77.4% (24/31) of cases with UTI and the preterm represent 22.6% (7/31) of them. Also a higher prevalence of UTI was present in full term compared with preterm neonates in a study done by Movahedian and his colleagues  in this study the full term represent 81.6% of cases with UTI, and the preterm represent 18.4% of them. But in contrast to our results, a study done by Tamim and his group  showed that the rate of UTI in preterm newborns was higher than full-term newborns.
We found 64.5% (20/31) of Group II (+ve cases) presented with fever, which is significantly higher than that of Group I (−ve cases). This is in agreement with a study done by Kanellopoulos et al0. that showed that fever was the most frequent symptom, and neonates had lower grade fever of short duration than infants.
In our study, 19.3% of neonates with UTI had jaundice (6/31), which is not significantly different than that in Group I (−ve cases) 15.9 (7/44). This finding disagrees with a study done by Movahedian et al. as they found the most common clinical findings of neonates with UTI was jaundice, which occurred in 68.4% of newborns, also another study done by Sedigheh et al. showed that (5.8%) of cases with neonatal jaundice were diagnosed to have UTI and the study revealed the UTI should be considered as a screening test in all cases of neonatal late onset jaundice.
In our study, urine cultures were performed for all cases with clinical suspicion of UTI in 31 of 75 cases (41.3%), this represents 15% of all cases admitted to NICU (31/206) [Table 3]. Lower percentages of +ve urine culture were recorded by Garcia et al. in California 2002 where the incidence of UTI of 160 participants enrolled, positive urine cultures were found in 12 infants (7.5%). This may be due to that Garcia  study done on asymptomatic, afebrile, jaundiced infants younger than 8 weeks but in our study the neonates were selected from NICU, where they are more susceptible to infection and have high risk factors.
|Table 3: Laboratory investigations and abdominal sonar of studied neonates|
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In our result 58.1% of +ve urine culture were due to E. coli and 42% were due to Klebsiella, this agrees with a study done by Zorc et al.  the most common pathogen that caused UTI was E. coli, which grew in 80% culture. Frequencies of other pathogens were as follows :Klebsiella pneumoniae (9%), also in a study done by Garcia et al.  E. coli was isolated from the urine in 33.3 % infants with a positive urine culture, Enterococcus from 16.6% patients, Enterobacter cloacae from 16.6% patients, and K. pneumoniae, group Streptococcus, Streptococcus viridans, and Staphylococcus aureus from 8.3 % of patient each. This difference may be due to small number of cases in our study and different locality and susceptibility to different organisms.
In our study blood culture was positive in 39 cases 52% and39/75 of cases with suspected UTI. The organisms encountered in this study were Klebsiella, group B streptococci and S. aureus. In agreement with our results, Tamim et al. found that 38% of infants with positive urine cultures had positive blood cultures. A lower percentage of + ve blood culture were recorded by Movahedian et al. in 2007 as positive blood cultures occurred in only 18.4% of neonates with UTI.
In our study 79.5% of cases with neonates admitted because of sepsis have proven UTI (31/39). Our study coincides with that of Falcão et al. in 2000, which showed that the presence of infection was one of the most prevalent associated risk factors (63.2%), therefore, UTI should be considered in all infants who have signs of sepsis. A lower percentage of UTI associated with septicemia was recorded by Movahedian et al. where UTI associated with septicemia was observed in 10.5%.
In our study urinary tract abnormalities in newborns with UTIs were seen in (9.6%) in 3 cases of 31 (one case of hydronephrosis, one vesicoureteric reflux and a case of grade I nephrocalcinosis). A higher percentage of urinary tract abnormalities were recorded by Sedigheh et al. as imaging studies for the infected infants with UTI was done and they discovered congenital urinary tract abnormalities in 4 out of 23 (17.39%) patients, which included vesicoureteric reflux, hydronephrosis, and pelvic ectasis, and only one patient had abnormal voiding cystourethrogram.
A limitations to our study was small number of cases.
| Conclusion|| |
This study has highlighted the need for routine urine analysis and culture, especially in high-risk newborns and to monitor the prevalence of UTI early in life. Also ultrasonographic screening should be done in all newborns with UTI; to save the newborns and prevent the risk of complications, which may end in renal scarring and renal failure. Cystourethrogram or DMSA was not done in all cases but in suspected cases only (by ultrasound abnormality or resistance to treatment) as UTI is a common association with neonatal sepsis (79.5%) in our study. VCUG is recommended after 1 week after UTI is treated.
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[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3]
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