Urinary tract infection in adults and children is addressed separately [1,2]. A urinary tract infection (UTI) in a neonate or young infant (under one month of age) can be a serious, life-threatening disorder that is often associated with bacteremia as well as congenital renal or genitourinary abnormalities. It affects up to 3% of preterm and 0.7% of term infants at some point in the first 3 months of life. It is estimated that up to 15% of febrile term infants who are older than 1 week have a UTI. UTIs are less common in the first few days of life and become more frequent by the third to fourth week of life [3-6]. Most UTIs in neonates are upper tract infections (pyelonephritis) and are thought to result primarily from ascending infection as opposed to bacteremia (which was classically believed to be the cause). Risk factors for a UTI include preterm delivery, congenital urinary tract abnormalities, vesicoureteral reflux (VUR), male sex, and uncircumcised penises [7,8]. Term neonates with UTI can present with fever, vomiting, poor feeding, poor weight gain, diarrhea, lethargy, hyperbilirubinemia (usually conjugated), irritability, tachycardia, tachypnea, cyanosis, or an unwell appearance. Preterm neonates may also display temperature instability, apneic or bradycardic episodes, hypoxia, feeding intolerance, or abdominal distention [9,10]. Escherichia coli is the most common causative agent, accounting for up to 80% of infections in term infants. In hospitalized preterm infants, a broader range of pathogens should be considered including Klebsiella spp, Staphylococcus spp, and in some cases, Candida spp (more common in extremely preterm infants). Other implicated bacterial pathogens include Enterococcus spp, Proteus spp, Enterobacter spp, and Pseudomonas aeruginosa [11,12]. Prompt identification and treatment of UTIs is important as they can cause renal scarring with subsequent hypertension or chronic kidney disease.In premature newborns hospitalized, Klebsiella and coagulase-negative Staphylococcus species are frequently detected as the causative agent. Candida types are an important urinary tract for premature babies weighing less than 1000 grams. is the causative agent of infection [13].Urinary tract infections in male infants and especially in uncircumcised male infants. The risk of infection is considerably higher than for female babies. urinary tract in the first trimester approximately 75% of cases of infection are male infants.1,6 Neonatal urinary tract infection in terms of its association with congenital renal and urinary system anomalies. is important [14]. Pelviectasis and mild hydronephrosis are the most common anomalies. 5-10% of patients have high-grade hydronephrosis, vesicoureteral reflux, and significant there are structural anomalies [1]. The aim was determine the prevalence of UTI and the causative agent in neonates with their antibiotics sensitivity patterns.

This study was designed as a cross-sectional study to investigate urinary tract infections (UTIs) among neonates over a 4-year period. The study was conducted in the neonatal unit of Children's Hospitals in Kirkuk city and private clinics. It included 91 neonates with suspected UTIs who were hospitalized with a clinical diagnosis of infection.

The study population consisted of neonates admitted to the neonatal unit with suspected UTIs. Inclusion criteria included neonates with a single pathogen growth in their urine culture. Exclusion criteria were prior hospitalization, major surgery, urinary catheterization, premature birth, and cases with multipathogen growth in the urine culture. Patient data were retrospectively obtained from medical records.

Ethical Approval

Ethical approval for the study was obtained from the local ethics committee. Written informed consent was waived due to the retrospective nature of the study.

Definition of UTI

A urinary tract infection was defined based on urine samples obtained by bladder catheterization with colony counts between 10,000–50,000 CFU/mL in the presence of pyuria or a colony count ≥50,000 CFU/mL in the absence of pyuria.

Data Collection

The following data were collected for each patient from the medical records:

• Demographic Information: Gender, gestational age (weeks of gestation), mode of delivery, and birth weight.

• Clinical Information: Postnatal age at the time of diagnosis, presenting complaints (e.g., fever, feeding difficulty, lethargy), physical examination findings (presence of fever, phimosis in male neonates).

• Laboratory Findings: Urine density, pH values, presence of pyuria, nitrite positivity, and types of microorganisms isolated from urine cultures. Antibiogram results were also recorded to evaluate antimicrobial susceptibility patterns.

• Blood Culture: Results of blood cultures, when available, were documented.

Sample Collection and Microbiological Analysis

Urine samples were collected by bladder catheterization to ensure sterility and minimize contamination. The samples were processed in the microbiology laboratory. The colony-forming units (CFU) per mL were determined, and cultures were evaluated for the presence of pyuria or significant bacterial growth. Urine samples with colony counts of 10,000–50,000 CFU/mL in the presence of pyuria or ≥50,000 CFU/mL in the absence of pyuria were classified as positive for UTI. Collected samples were cultured on various culture media including Blood agar, MacConky agar, Mannitol salt agar, Sharpe deman Rosa agar and Eosin methylene blue agar. Incubated for 24-48 hours.colonies grown on these media were identified through a series of procedures including Gram staining and various Biochemical tests. The Vitek2 automated system was employed to enhance the accuracy of bacterial identification and susceptibility testing.

Statistical Analysis

The recorded data were analyzed using statistical software. Categorical variables were summarized as frequencies and percentages, while continuous variables were presented as means and standard deviations. Comparisons between groups were performed using appropriate statistical tests, such as the chi-square test for categorical data and t-tests or Mann-Whitney U tests for continuous data. Correlations and relationships between variables were also assessed.

Table 1 provides a clear overview of the urine culture results among neonates diagnosed with urinary tract infection (UTI). The data indicate that out of 90 neonates, a majority (55, 61.11%) had a positive bacterial culture, confirming the presence of bacterial infection. In contrast, 35 neonates (38.89%) had a negative bacterial culture, suggesting either non-bacterial causes of UTI symptoms or potential limitations in detection

Table 1: Results of urine culture among Neonates with UTI.

Table 2 highlights the distribution of bacterial types isolated from neonates with urinary tract infections (UTIs). Among the 55 neonates with positive urine cultures, Gram-negative bacteria were the most prevalent, accounting for 35 cases (63.64%), while Gram-positive bacteria were identified in 20 cases (36.36%).

Table 2: Types of isolated bacteria   

Table 3 presents the detailed distribution of bacterial species isolated from neonates with urinary tract infections (UTIs). Among the 55 neonates with positive urine cultures, Escherichia coli emerged as the most common pathogen, accounting for 15 cases (27.27%), followed by Klebsiella pneumoniae with 10 cases (18.18%). Other notable species included Staphylococcus aureus (7 cases, 12.73%) and Proteus mirabilis and Streptococcus faecalis (each 5 cases, 9.09%). Less frequently isolated bacteria included Serratia marcescens (3 cases, 5.45%), Proteus vulgaris (3 cases, 5.45%), Staphylococcus epidermidis, Staphylococcus saprophyticus, and Pseudomonas aeruginosa (each 2 cases, 3.64%), with Enterobacter cloacae being the least common (1 case, 1.82%). The data highlight the predominance of Gram-negative bacteria, particularly Escherichia coli, as a key pathogen in neonatal UTIs, with a diverse array of other bacterial species also contributing to the infection profile.

Table 3: Distribution of isolated bacteria 

Table 4 illustrates the distribution of clinical features observed in neonates with positive urinary tract infections (UTIs). Among the 55 cases, dysuria was the most prevalent symptom, reported in 40 neonates (72.73%), highlighting its significance as a key indicator of UTI in this population. Fever, although less common, was present in 15 cases (27.27%), underscoring its role as a possible but not definitive symptom of neonatal UTI.

Table 4: Distribution of Clinical Features in UTI neonates

The highest proportion of cases occurred in neonates aged 8–28 days, accounting for 25 cases (45.45%), followed by those older than 28 days with 20 cases (36.36%), while the youngest age group, 0–7 days, had the lowest frequency at 10 cases (18.18%). In terms of gender, females were more commonly affected, comprising 36 cases (65.45%), compared to males, who accounted for 19 cases (34.55%). These findings highlight a significant prevalence of UTIs in neonates aged 8–28 days and a higher susceptibility among females, underscoring the need for focused clinical attention in these groups.

Table 5: Distribution of positive UTI cases among neonates by age group and gender.

Among the positive UTI cases, the most common risk factors were prolonged hospitalization (15 cases, 27.27%) and prematurity (12 cases, 21.82%), followed by indwelling catheter use (8 cases, 14.55%). Interestingly, 20 neonates (36.36%) with positive UTI cases had no identifiable risk factors. In contrast, among the negative UTI cases, the majority (22 cases, 62.86%) had no associated risk factors, while prolonged hospitalization, prematurity, and indwelling catheter use accounted for 17.14% (6 cases), 14.29% (5 cases), and 5.71% (2 cases), respectively. These findings suggest that risk factors like prolonged hospitalization, prematurity, and indwelling catheter use are more prevalent in neonates with UTIs, emphasizing the need for preventive measures in these high-risk groups.

Table 6: Risk Factors Associated with UTI

The table 7 outlines the antibiotic sensitivity patterns of bacterial isolates from neonates with UTIs, revealing significant variations in susceptibility across different pathogens. E. coli, the most common isolate, showed high sensitivity to Ceftazidime (93.02%), Cefotaxime (86.04%), and Amoxiclav (81.39%), but demonstrated resistance to Ampicillin (6.97%) and Erythromycin (6.97%). S. aureus displayed strong sensitivity to Oxacillin (88.23%), Ciprofloxacin (88.23%), and Tobramycin (82.35%), with complete resistance to Ampicillin (0%). S. faecalis had limited sensitivity overall, with the highest being to Nitrofurantoin (80%) and Amoxiclav (60%), while being resistant to Ampicillin (0%). K. pneumoniae was most sensitive to Amoxiclav (81.48%) and Cefotaxime (77.77%), with resistance to multiple antibiotics including Ampicillin (0%). E. cloacae, although less common, exhibited 100% sensitivity to Ciprofloxacin, Tobramycin, and Amoxiclav, but resistance to most other antibiotics. P. mirabilis showed high sensitivity to Amoxiclav (88.88%), Cefotaxime (94.44%), and Amikacin (83.33%), while being completely resistant to Ampicillin.

Table 7: Antibiotic Sensitivity Patterns of Bacterial Isolates from neonates with UTI

The present study provides important insights into the prevalence, microbiological profile, and risk factors associated with neonatal urinary tract infections (UTIs) in a hospital-based population. The findings align with previous studies while highlighting unique regional variations and challenges in diagnosis and management. This study identified a significant prevalence of bacterial UTIs in neonates, with positive urine cultures observed in 61.11% of cases. The predominance of Escherichia coli as the causative organism (27.27%) is consistent with prior studies indicating E. coli as the leading pathogen in neonatal UTIs [1,2]. Similarly, Klebsiella pneumoniae (18.18%) and Staphylococcus aureus (12.73%) were frequently isolated, corroborating findings from other studies highlighting these pathogens as key contributors, particularly in hospitalized and preterm neonates [3,4]. The most common bacterial etiology for neonatal UTIs, similar to other age groups, is Escherichia coli. [15,16]. However, some studies found that the overall burden of disease by E. coli was lower in this age group (about 50% of all positive cultures) compared with older age groups in which E. coli is responsible for up to 80% of UTIs [17,18]. In particular, male infants with vesicoureteral reflux (VUR) were more likely to present with UTIs caused by other pathogens [19,20]. These pathogens include other gram-negative organisms: Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Proteus vulgaris, Enterobacter aerogenes, Pseudomonas aeruginosa, and Morganella morganii [21,22]. Neonatal UTI with gram-positive organisms is rare, but cases of Enterococcus faecalis, Staphylococcus aureus, Group B streptococcus, and Streptococcus pneumonia have been reported [23-25]. Coagulase-negative staphylococci may be causative agents in premature infants, with isolation of the organism in 14% of catheterized urine culture samples from infants with suspected infection and 18% concordance with positive blood cultures [26,27]. However, this finding remains controversial; one study, which included mostly premature infants, showed a less than 1% incidence of coagulase-negative staphylococci UTI  The detection of less common bacteria, including Proteus mirabilis, Serratia marcescens, and Enterobacter cloacae, underscores the diversity of pathogens and the need for targeted diagnostic and therapeutic approaches [5, 6].Dysuria was the most common clinical symptom (72.73%), followed by fever (27.27%), similar to reports  [7,5]. These findings emphasize the need for clinicians to consider UTIs in neonates presenting with non-specific symptoms, particularly in the absence of fever. The study also observed a higher prevalence of UTIs in female neonates (65.45%) compared to males (34.55%), a trend reported in other studies [2,8]. However, this differs from findings in uncircumcised male infants, who are at increased risk of UTI [8,9]. Key risk factors identified in this study included prolonged hospitalization (27.27%), prematurity (21.82%), and indwelling catheter use (14.55%). These findings align with prior research highlighting these as significant contributors to neonatal UTIs [10,11]. Interestingly, 36.36% of cases had no identifiable risk factors, indicating the multifactorial nature of UTI pathogenesis in neonates and the importance of vigilance in all hospitalized neonates [3,6].The study's antibiotic sensitivity results reinforce the critical role of local antibiograms in guiding empiric therapy. E. coli demonstrated high sensitivity to ceftazidime (93.02%) and cefotaxime (86.04%), consistent with global trends [5,12]. However, resistance to ampicillin (6.97%) and erythromycin (6.97%) reflects ongoing challenges with antibiotic resistance in neonates [13]. Similarly, K. pneumoniae exhibited sensitivity to amoxiclav (81.48%) but resistance to multiple antibiotics, highlighting the need for judicious antibiotic use to limit the spread of resistant strains [14]. The findings for Gram-positive bacteria, such as S. aureus and S. faecalis, showed high sensitivity to oxacillin (88.23% and 100%, respectively), but resistance to ampicillin was universal. These patterns underscore the importance of including beta-lactamase-stable antibiotics in empiric regimens for suspected UTIs caused by Gram-positive organisms [3, 7]. This study underscores the importance of early and accurate diagnosis of UTIs in neonates. Non-specific clinical presentations and the risk of severe complications necessitate routine screening in high-risk neonates, especially those with prolonged hospitalization, prematurity, or indwelling catheterization. Additionally, the predominance of Gram-negative bacteria, particularly E. coli, supports the use of third-generation cephalosporins as first-line therapy, while susceptibility patterns for Gram-positive bacteria indicate the need for tailored therapy based on local antibiograms [11,15]. The retrospective design of this study may have introduced biases related to incomplete or inconsistent documentation. Moreover, the exclusion of neonates with multipathogen growth could limit the generalizability of findings to cases with mixed infections. Future prospective studies should explore the role of advanced diagnostic techniques, such as polymerase chain reaction (PCR), in improving pathogen detection and characterizing resistance mechanisms [16,17].

Neonatal UTIs remain a significant clinical challenge, particularly in hospitalized populations. This study highlights the high prevalence of E. coli and K. pneumoniae as causative agents, the non-specific clinical features of UTIs in neonates, and the importance of antibiotic stewardship in managing these infections. Targeted interventions, including routine surveillance and judicious antibiotic use, are essential to optimize outcomes and reduce the burden of antibiotic resistance in this vulnerable population.

The authors declare that they have no conflict of interest

No funding sources

The study was approved by the Kirkuk Health Directorate, Iraq.

1. Walawender et al. "Diagnosis and Imaging of Neonatal UTIs" Pediatrics & Neonatology 61.2 (2020): pp. 195-200. https://doi.org/10.1016/j.pedneo.2019.08.004.

2. Ozdogan et al. "Urinary Tract Infections in Neonates with Unexplained Pathological Indirect Hyperbilirubinemia: Prevalence and Significance" Pediatrics & Neonatology 59.3 (2018): pp. 305-309. https://doi.org/10.1016/j.pedneo.2017.05.003.

3. Bay and Anacleto. "Clinical and Laboratory Profile of Urinary Tract Infection in Children Among Children at Outpatient Clinic of a Tertiary Hospital" PIDSPJ 11.1 (2010): pp. 10-16.

4. Abda et al. "Urinary Tract Infections in Very Premature Neonates: The Definition Dilemma" Journal of Perinatology 44.5 (2024): pp. 731-738. https://doi.org/10.1038/s41372-024-01028-9.

5. Rai et al. "Causative Agents of Urinary Tract Infections in Children and Their Antibiotic Sensitivity Pattern: A Hospital-Based Study" Nepal Medical College Journal 10.2 (2008): pp. 86-90.

6. Vishwanath et al. "A Prospective Observational Study on Urinary Tract Infection in Neonatal Sepsis" International Journal of Academic Medicine and Pharmacy 5.4 (2023): pp. 110-114.

7. Mohammed and Anahtar. "Screening Test for Detection of Urinary Tract Infections: Evolution of Urinary Leukocytes Esterase Dipstick Test" TAF Preventive Medicine Bulletin 7 (2008): pp. 187-190.

8. Harb et al. "Prevalence and Clinical Significance of Urinary Tract Infection Among Neonates Presenting with Unexplained Hyperbilirubinemia in Lebanon: A Retrospective Study" Infection & Chemotherapy 55.2 (2023): pp. 194. https://doi.org/10.3947/ic.2023.55.2.194.

9. Jimmy and Bakar. "Evaluation of Urinary Tract Infection Among Neonates and Children Using Urine FEME and Urine Culture" AIP Conference Proceedings 2625.1 (2023): AIP Publishing.

10. Al-Momani. "Microbiological Study of Urinary Tract Infection in Children at Princess Haya Hospital in South of Jordan" Middle East Journal of Family Medicine 4.2 (2006): pp. 3-7.

11. Kim et al. "Urinary Tract Dilation Classification System for Predicting Surgical Management and Urinary Tract Infection in Neonates and Young Infants: A Systematic Review and Meta-Analysis" Pediatric Radiology 29 Jan. 2024: pp. 1-0. https://doi.org/10.1007/s00247-024-05480-5.

12. Abdulhadi et al. "Organisms Causing Urinary Tract Infection in Pediatric Patients at Murtala Muhammad Specialist Hospital, Kano, Nigeria" International Journal of Biomedical and Health Sciences 4.4 (2008): pp. 165-167.

13. Ketema et al. "Determinants of Neonatal Sepsis Among Neonates Admitted in a Neonatal Intensive Care Unit at Jinka General Hospital, Southern Ethiopia" International Journal of Nursing and Midwifery 11.3 (2019): pp. 18-24.

14. Nugent et al. "Risk of Meningitis in Infants Aged 29 to 90 Days with Urinary Tract Infection: A Systematic Review and Meta-Analysis" The Journal of Pediatrics 212 (2019): pp. 102-110. https://doi.org/10.1016/j.jpeds.2019.04.050.

15. Lo et al. "Clinical and Laboratory Features of Urinary Tract Infections in Young Infants" Brazilian Journal of Nephrology 40.1 (2018): pp. 66-72. https://doi.org/10.1590/2175-8239-JBN-2017-0154.

16. Oliveira and Mak. "Urinary Tract Infection in Pediatrics: An Overview" Jornal de Pediatria 96 (2020): pp. 65-79. https://doi.org/10.1016/j.jped.2019.08.003.

17. Wallace et al. "Renal Ultrasound for Infants Younger Than 2 Months with a Febrile Urinary Tract Infection" AJR American Journal of Roentgenology 205.4 (2015): pp. 894-898. https://doi.org/10.2214/AJR.15.14501.

18. Arshad and Seed. "Urinary Tract Infections in the Infant" Clinical Perinatology 42.1 (2015): pp. 17-28. https://doi.org/10.1016/j.clp.2014.11.003.

19. Goldberg et al. "Long-Term Follow-Up of Premature Infants with Urinary Tract Infection" European Journal of Pediatrics 180.9 (2021): pp. 3059-3066. https://doi.org/10.1007/s00431-021-03989-7.

20. Shahian et al. "Unexplained Neonatal Jaundice as an Early Diagnostic Sign of Urinary Tract Infection" International Journal of Infectious Diseases 16.7 (2012): pp. 487-490. https://doi.org/10.1016/j.ijid.2012.03.028.

21. Lai et al. "Diagnosis and Management of Urinary Tract Infections in Premature and Term Infants" NeoReviews 19.6 (2018): pp. e337-e348. https://doi.org/10.1542/neo.19-6-e337.

22. Tola et al. "Prevalence of UTI Among Iranian Infants with Prolonged Jaundice, and Its Main Causes: A Systematic Review and Meta-Analysis Study" Journal of Pediatric Urology 14.2 (2018): pp. 108-115. https://doi.org/10.1016/j.jpurol.2017.11.002.

23. Tzimenatos et al. "Accuracy of the Urinalysis for Urinary Tract Infections in Febrile Infants 60 Days and Younger" Pediatrics 141.2 (2018): e20173068. https://doi.org/10.1542/peds.2017-3068.

24. Bilgin et al. "Maternal Urinary Tract Infection: Is It Associated with Neonatal Urinary Tract Infection?" Journal of Family & Reproductive Health 15.1 (2021): pp. 8.

25. Herreros Fernández et al. "A New Technique for Fast and Safe Collection of Urine in Newborns" Archives of Disease in Childhood 98.1 (2013): pp. 27-29. https://doi.org/10.1136/archdischild-2012-302475.

Özcan et al. "Association Between Early Idiopathic Neonatal Jaundice and Urinary Tract Infections" Clinical Medicine Insights: Pediatrics 11 (2017): 1179556517701118. https://doi.org/10.1177/1179556517701118.