Incidence and risk factors of urinary tract infection in very low birth weight infants

Urinary tract infections in very premature neonates: the definition dilemma

BACKGROUND AND OBJECTIVES

Data on urinary tract infections (UTIs) in very preterm neonates (VPTNs) are scarce. We aimed to (i) describe the characteristics of UTIs in VPTNs and (ii) compare the diagnostic practices of neonatal clinicians to established pediatric guidelines.

METHODS

All VPTNs (<29 weeks GA) with a suspected UTI at the CHU Sainte-Justine neonatal intensive care unit from January 1, 2014, and December 31, 2019, were included and divided into two definition categories: Possible UTI, and Definite UTI.

RESULTS

Most episodes were Possible UTI (87%). Symptoms of UTIs and pathogens varied based on the definition category. A positive urinalysis was obtained in 25%. Possible UTI episodes grew 2 organisms in 62% of cases and <50,000 CFU/mL in 62% of cases.

CONCLUSION

Characteristics of UTIs in VPTNs vary based on the definition category and case definitions used by clinicians differ from that of established pediatric guidelines.

Urinary Tract Infection Epidemiology in NICUs in the United States

OBJECTIVE

Our objective was to characterize the incidence, associated clinical factors, timing of infection, microbiology, and incidence of concordant blood culture of urinary tract infections (UTIs) in very low birth weight (VLBW <1,500g) infants.

STUDY DESIGN

Multicenter observational cohort study of VLBW infants with gestational age (GA) ≤32 weeks, still hospitalized on postnatal day 7, and discharged 2010 to 2018 from Pediatrix Medical Group neonatal intensive care units. Demographic and clinical characteristics of infants with and without UTI were compared. Multivariable logistic regression evaluated adjusted odds of UTI diagnosis.

RESULTS

Of 86,492 included infants, 5,988 (7%) had a UTI. The most common pathogen was Enterococcus spp. (20%), followed by Escherichia coli (19%) and Klebsiella spp. (18%). Candida spp. (6%) was the most common nonbacterial pathogen. Concordant-positive blood culture was present in 8% of infants with UTI diagnoses. UTI was associated with lower GA, male sex, vaginal delivery, prenatal steroid exposure, and longer duration of hospitalization.

CONCLUSION

UTI is a common cause of infection in VLBW infants, especially among the smallest, most premature, male infants, and those with a longer duration of hospitalization. Neonatal clinicians should consider obtaining urine culture in the setting of late-onset sepsis evaluations in VLBW infants.

KEY POINTS

· UTI is a common cause of LOS in VLBW infants.. · The most common pathogens are Enterococcus spp. and E. coli.. · UTI risk varies among different VLBW infant populations.. · Next steps should include evaluation of preventative measures..

Incidence and risk factors of urinary tract infection in neonatal sepsis

Background

Neonates with sepsis may have concurrent urinary tract infection (UTI), which may be asymptomatic or have nonspecific symptoms. Failure to diagnose UTI, resulting in a delay of appropriate therapy, has been reported to cause renal scarring, hypertension, and kidney failure among infants. This study aimed to determine the contribution of UTI to neonatal sepsis and to assess different risk factors that could be associated with UTI. This cross-sectional study was conducted at the Neonatal Intensive Care Unit (NICU) of Fayoum University Hospital, Fayoum, Egypt, between March 2018 and January 2019. Neonates of both genders from birth to the 28th day of life with clinical features of either early- or late-onset sepsis (during or after the first 3 days of life, respectively) were enrolled in this study. All neonates were subjected to complete history taking from the parents, full clinical examination, and laboratory investigations including complete blood count, C-reactive protein, blood culture, and urine culture.

Results

The current study included 100 neonates admitted to the NICU with clinical and laboratory features of sepsis. Positive blood culture (proven sepsis) was detected in 60%, and the proportion of positive urine culture (UTI) in the entire study group was 11%. The incidence of UTI was 11.7% in proven sepsis compared to 10% in suspected sepsis, and it was 16.36% in late-onset sepsis (LOS) versus 4.44% in early-onset sepsis (EOS). There was a statistically significant association between poor feeding and feeding intolerance and positive urine culture (UTI). Leukopenia and expert panel criteria score showed high sensitivity (81.80% and 90.90%, respectively) but low specificity for the diagnosis of UTI.

Conclusions

Gram-negative bacteria have been highly suspected in cases of neonatal sepsis. Poor feeding and feeding intolerance have association with positive urine culture. Finally, urine culture for sepsis was recommended especially in the late type.

Short-course intravenous antibiotics for young infants with urinary tract infection

OBJECTIVE

Shorter courses of intravenous antibiotics for young infants with urinary tract infection (UTI) have myriad advantages. As practice shifts toward shorter intravenous treatment courses, this study aimed to determine the safety of early intravenous-to-oral antibiotic switch and identify risk factors for bacteraemia with UTI.

METHODS

Retrospective audit of infants aged ≤90 days with a positive urine culture at a quaternary paediatric hospital over 4 years (2016-2020). Data were collected from the hospital electronic medical record and laboratory information system. Short-course intravenous antibiotic duration was defined as <48 hours for non-bacteraemic UTI and <7 days for bacteraemic UTI. Multivariate analysis was used to determine patient factors predicting bacteraemia.

RESULTS

Among 427 infants with non-bacteraemic UTI, 257 (60.2%) were treated for <48 hours. Clinicians prescribed shorter intravenous courses to infants who were female, aged >30 days, afebrile and those without bacteraemia or cerebrospinal fluid pleocytosis. Treatment failure (30-day UTI recurrence) occurred in 6/451 (1.3%) infants. All had non-bacteraemic UTI and one received <48 hours of intravenous antibiotics. None had serious complications (bacteraemia, meningitis, death). Follow-up audiology occurred in 21/31 (68%) infants with cerebrospinal fluid pleocytosis, and one had sensorineural hearing loss. Bacteraemia occurred in 24/451 (5.3%) infants, with 10 receiving <7 days intravenous antibiotics with no treatment failure. Fever and pyelonephritis were independent predictors of bacteraemia.

CONCLUSION

Short-course intravenous antibiotics for <48 hours for young infants with non-bacteraemic UTI should be considered, provided meningitis has been excluded. Treatment failure and serious complications were rare in young infants with UTI.

Validity of serum and urinary hepcidin as biomarkers for late-onset sepsis in premature infants

Background:

Sepsis remains one of the leading causes of neonatal morbidity and mortality, particularly among premature infants. Blood culture is the ‘gold standard’ for the diagnosis of neonatal sepsis but is associated with several pitfalls.

Aim of the work:

We aim to evaluate the validity of measuring serum (S.Hep) and urinary hepcidin (U.Hep) concentrations as diagnostic biomarkers for late-onset sepsis (LOS) in preterm infants.

Patients and Methods:

The current case-control study included 73 cases of clinically and laboratory confirmed late-onset sepsis as the ‘case group’ and 50 nonseptic premature infants of comparable age and sex as the ‘control group’. S.Hep and U.Hep concentrations were evaluated at enrollment (acute sample) and after 1 week of treatment (convalescent sample).

Results:

Patients had a statistically significant higher concentration of both S.Hep and U.Hep as compared with nonseptic controls (p = 0.0001). Similarly, a significant reduction of both S.Hep and U.Hep was detected after 1 week of treatment (p = 0.001). A cut-off value of ⩾ 94.8 ng/ml of S.Hep and ⩾ 264 ng/mg of U.Hep/urinary creatinine showed high sensitivity, specificity, and positive predictive value in the diagnosis of neonatal LOS.

Conclusions:

Both S.Hep and U.Hep can function as promising accurate and rapid surrogate tests for the diagnosis of LOS. U.Hep measurement has the advantage of being noninvasive, with no hazards of phlebotomy, and is less variable throughout the day.

Practice Summary of Antimicrobial Therapy for Commonly Encountered Conditions in the Neonatal Intensive Care Unit: A Canadian Perspective

Neonates are highly susceptible to infections owing to their immature cellular and humoral immune functions, as well the need for invasive devices. There is a wide practice variation in the choice and duration of antimicrobial treatment, even for relatively common conditions in the NICU, attributed to the lack of evidence-based guidelines. Early decisive treatment with broad-spectrum antimicrobials is the preferred clinical choice for treating sick infants with possible bacterial infection. Prolonged antimicrobial exposure among infants without clear indications has been associated with adverse neonatal outcomes and increased drug resistance. Herein, we review and summarize the best practices from the existing literature regarding antimicrobial use in commonly encountered conditions in neonates.

Long-term follow-up of premature infants with urinary tract infection

Urinary tract infection (UTI) is common in preterm infants and may have long-term sequela, such as recurrent infections and renal scarring in older children. We assessed long-term outcomes of preterm infants with UTI, born during 1996-2008 in Schneider Children's Medical Center's neonatal intensive care unit (NICU), and incidence of UTI recurrence. Of 89 preterm infants, seven were excluded due to prenatal diagnosis of congenital anomalies of the kidney and urinary tract (CAKUT), 41 interviewed by phone, 18 presented for follow-up evaluation in the nephrology clinic, and 23 lost to follow-up. No patient who completed follow-up reported additional UTI episodes or issues related to kidney and urinary tract. Clinically evaluated participants were 17.1 ± 3.6 years, born prematurely at 29.4 ± 4 weeks. All had a normal estimated glomerular filtration rate of >90 ml/min/1.73m²; four (22%) had systolic blood pressure >90th percentile; none had proteinuria (mean protein/creatinine ratio 0.09 ± 0.04 mg/mg) or albuminuria (mean albumin/creatinine ratio 10.2 ± 6.3 mcg/mg). Renal ultrasonography done in the first years of life in 12 (66%) patients demonstrated normal kidney size and structure.Conclusion: In this pilot study, a single episode of UTI in premature infants without CAKUT did not constitute a risk factor for recurrence of infections or kidney injury in their first two decades of life. Thus, normal ultrasound in NICU excluding CAKUT may be sufficient for premature patients with UTI, with no need of further imaging or long-term nephrology follow-up. What is Known: • Urinary tract infection (UTI) is one of the most common bacterial infections in neonates and premature infants. Risk factors for UTI recurrence in children are congenital anomalies of the kidney and urinary tract (CAKUT) and bladder and bowel dysfunction. • The recurrence rate and long-term renal sequela of UTI in preterm infants have not been studied. Guidelines regarding management and long-term follow-up for infants less than 2 months old are lacking. What is New: • A single episode of UTI in premature infants without CAKUT probably does not constitute a risk factor for UTI recurrence, and it is unlikely to cause renal injury in the first two decades of life. • For premature infants with UTI without sonographic diagnosis of CAKUT in NICU, prophylactic antibiotic treatment, further imaging, or long-term nephrology follow-up may be unnecessary.

The Role of a NICU Hepatology Consult Service in Assessing Liver Dysfunction in the Premature Infant

Liver dysfunction is common in the neonatal intensive care unit (NICU). Literature exists on the presentation of primary liver disease in the NICU but little has been published on general liver dysfunction in the NICU. This is a retrospective observational study of hepatology consultations and outcomes in a large referral NICU. 157 babies were evaluated by a single hepatologist and followed to resolution of disease, death, or lost to follow-up as outpatients. Infectious etiologies were the most common cause for liver dysfunction in the NICU, followed by shock, genetic abnormalities, cardiac disease, large heme loads, and hypothyroidism. Primary liver disease was rare. Liver dysfunction in the sick preterm infant was often multifactorial, and the distribution of diagnoses differs from that seen in the term baby. The liver dysfunction may last well beyond discharge from the NICU and may result in death.

Urinary tract infections in very low birthweight infants: A two-center analysis of microbiology, imaging and heart rate characteristics

BACKGROUND

Increased understanding of characteristics of urinary tract infection (UTI) among very low birthweight infants (VLBW) might lead to improvement in detection and treatment. Continuous monitoring for abnormal heart rate characteristics (HRC) could provide early warning of UTIs.

OBJECTIVE

Describe the characteristics of UTI, including HRC, in VLBW infants.

METHODS

We reviewed records of VLBW infants admitted from 2005-2010 at two academic centers participating in a randomized clinical trial of HRC monitoring. Results of all urine cultures, renal ultrasounds (RUS), and voiding cystourethrograms (VCUG) were assessed. Change in the HRC index was analyzed before and after UTI.

RESULTS

Of 823 VLBW infants (27.7±2.9 weeks GA, 53% male), 378 had > / = 1 urine culture obtained. A UTI (≥10,000 CFU and >five days of antibiotics) was diagnosed in 80 infants, (10% prevalence, mean GA 25.8±2.0 weeks, 76% male). Prophylactic antibiotics were administered to 29 (36%) infants after UTI, of whom four (14%) had another UTI. Recurrent UTI also occurred in 7/51 (14%) of infants not on uroprophylaxis after their first UTI. RUS was performed after UTI in 78%, and hydronephrosis and other major anomalies were found in 19%. A VCUG was performed in 48% of infants and 18% demonstrated vesicoureteral reflux (VUR). The mean HRC rose and fell significantly in the two days before and after diagnosis of UTI.

CONCLUSIONS

UTI was diagnosed in 10% of VLBW infants, and the HRC index increased prior to diagnosis, suggesting that continuous HRC monitoring in the NICU might allow earlier diagnosis and treatment of UTI.

Neonatal Sepsis

Neonatal sepsis is associated with severe morbidity and mortality in the neonatal period. Clinical manifestations range from subclinical infection to severe local or systemic infection. Neonatal sepsis is divided into three groups as early-onset neonatal sepsis, late-onset neonatal sepsis and very late-onset neonatal sepsis according to the time of the onset. It was observed that the incidence of early-onset neonatal sepsis decreased with intrapartum antibiotic treatment. However, the incidence of late-onset neonatal sepsis has increased with the increase in the survival rate of preterm and very low weight babies. The source of the causative pathogen may be acquisition from the intrauterine origin but may also acquisition from maternal flora, hospital or community. Prematurity, low birth weight, chorioamnionitis, premature prolonged rupture of membranes, resuscitation, low APGAR score, inability to breastfeed, prolonged hospital stay and invasive procedures are among the risk factors. This article reviews current information on the definition, classification, epidemiology, risk factors, pathogenesis, clinical symptoms, diagnostic methods and treatment of neonatal sepsis.

Cholestasis in the Premature Infant

Liver dysfunction is a common problem in the sick premature infant. The dysfunction is usually multifactorial and often underlies a combination of liver immaturity, comorbidities, and/or the presence of primary liver disease. The liver of the preterm infant has a paucity of bile ducts, low levels of many hepatic enzymes and transporters, and a small bile acid pool. Many other organ systems are immature as well and do not respond to stress the way they would later in infancy. This articles discusses how prematurity affects the liver, how it responds to secondary insults, and approaches to evaluation.

Prevalence and predictors of urinary tract infection in full-term and preterm neonates

Background

Early and prompt diagnosis of urinary tract infection (UTI) in neonates has important therapeutic implications. The aim of this study was to evaluate the prevalence of UTI in neonates admitted to a referral neonatal intensive care unit (NICU) and to identify predictors associated with an increased risk of UTI in NICU population.

Results

The prevalence of culture-proven UTI in the studied neonates was 6.67%. Moreover, UTI was more frequent (70%) among full-term neonates. Additionally, both fever and pyuria were the only clinical and laboratory findings that showed significant association with UTI (p < 0.05). Binary logistic regression revealed that neonates with pyuria in urine analysis were 5.44 times more liable to have UTI, while the presence of fever constitutes a risk of only 0.166 (odds ratios were 5.44 and 0.166, respectively). Additionally, sensitivity, specificity, positive predictive value, and negative predictive value of the regression model were 50.0, 94.5, 20.05, and 98.57%, respectively.

Conclusions

We conclude that UTI is not uncommon in full-term neonates admitted in NICU. Additionally, pyuria was significantly related to positive urine culture and its detection in urine analysis increases the likelihood of UTI by 5.44 times.

Association of Nurse Staffing With Nosocomial Infections of Very Low-Birth-Weight Infants

Prior studies have reported inconsistent findings regarding the relationship between nurse staffing and nosocomial infections in very low-birth-weight (VLBW) infants. Little is known about whether similar associations occur in Korea. The purpose of this study was to identify the nurse staffing of neonatal intensive care units (NICUs) in Korea and to verify the association between nurse staffing and nosocomial infections among VLBW infants in NICUs. We selected 4654 VLBW infants admitted to 52 hospitals. Nosocomial infections were defined as incidence of bloodstream infection, urinary tract infection (UTI), or rotavirus infection. The average number of NICU patients per nurse was 4.51(minimum-maximum: 2.38-8.16). Hospitals with a higher number of patients per nurse exhibited a significant increased UTI rate (P = .005) and rotavirus infection rate (P = .025) in the univariate analysis. After adjusting for all patient and hospital characteristics, UTI significantly increased with increasing number of patients per nurse (odds ratio [OR] = 1.79; 95% confidence interval, 1.29-2.47), while bloodstream infection (OR = 0.93; 95% confidence interval, 0.79-1.09) and rotavirus infection (OR = 1.14; 95% confidence interval, 0.92-1.41) were not significant. These findings revealed that a nurse staffing in NICUs is an important factor for preventing UTI among VLBW infants.

Neonatal Sepsis

Purpose of Review

Neonatal sepsis is a diagnosis made in infants less than 28 days of life and consists of a clinical syndrome that may include systemic signs of infection, circulatory shock, and multisystem organ failure.

Recent Findings

Commonly involved bacteria include Staphylococcus aureus and Escherichia coli. Risk factors include central venous catheter use and prolonged hospitalization. Neonates are at significant risk of delayed recognition of sepsis until more ominous clinical findings and vital sign abnormalities develop. Blood culture remains the gold standard for diagnosis.

Summary

Neonatal sepsis remains an important diagnosis requiring a high index of suspicion. Immediate treatment with antibiotics is imperative.

Progress of Research in Neonatal Sepsis

Neonatal sepsis remains a significant global problem with little progress made despite major efforts. At present, there is a lack of an accepted international consensus on the definition, diagnosis, and treatment of neonatal sepsis; the unclear understanding of the pathogenesis of neonatal sepsis leads to blindness in treatment, which will result in an unsatisfactory therapeutic outcome. In addition, some serious diseases caused by noninfectious factors, such as trauma, stress, asphyxia, and so on, have very similar pathophysiological results with neonatal sepsis. In this review we synthesize the recent advances in definition, incidence, causative agents, risk factors, pathophysiology, clinical manifestations, and diagnosis and treatment of neonatal sepsis. Of course, there are still many challenges to neonatal sepsis in many ways.

Urinary tract infection is common in VLBW infants

OBJECTIVE

Determine the significance of urinary tract infection (UTI) as a cause of late onset sepsis (LOS) in very low birth weight (VLBW) infants in the Neonatal Intensive Care Unit (NICU).

STUDY DESIGN

Analysis of blood, cerebrospinal fluid and urine culture results in VLBW infants >72-h old, admitted to the Georgetown University Hospital NICU between 2005 and 2015.

RESULT

Of 527 VLBW infants, 297 (56.4%) underwent 911 evaluations for LOS; only one-third included urine cultures. UTI was diagnosed in 8.5% of VLBW infants (range 2-15.9%) and in 13.8% of infants weighing < 1000 g at birth. Gram-negative infections predominated. Concomitant blood cultures were negative in 96% of infants. UTI was more common than bloodstream infection by 2015.

CONCLUSION

UTI is a significant cause of infection in VLBW infants. Urine culture should be included in all LOS evaluations in order to facilitate accurate diagnosis and appropriate antibiotic therapy.

Do infants in the neonatal intensive care unit diagnosed with urinary tract infection need a routine voiding cystourethrogram?

OBJECTIVE

To determine if infants diagnosed with urinary tract infection (UTI) in the neonatal intensive care unit (NICU) require a routine voiding cystourethrogram (VCUG).

STUDY DESIGN

Retrospective data analysis from three centers for infants admitted to the NICU born between 2000 and 2013 and diagnosed with UTI.

RESULTS

One hundred twenty-six infants from three centers were diagnosed with UTI during their hospitalization. Renal ultrasound (RUS) was performed in 115 infants (91.2%), of which 69 (60%) were abnormal. Mild to moderate hydronephrosis or pelviectasis were the most common abnormalities identified (n = 34, 30%). There were 14 infants (12%) with severe abnormalities on RUS. VCUG was performed in 71 infants (56%), of which 3 (4%) were interpreted as abnormal with grade 2 vesicoureteral reflux (VUR) or less (two infants were with normal RUS and one infant was with abnormal RUS).

CONCLUSIONS

More than 50% of infants with a UTI had an abnormal RUS but severe abnormalities were found only in 11% of infants. Only 4% of infants with UTI had VUR; none of these infants had severe VUR on VCUG. A routine VCUG after UTI in the NICU has a low yield and may be reserved for infants with severe or persistent abnormalities on RUS.

Neonatal sepsis

Neonatal sepsis is the cause of substantial morbidity and mortality. Precise estimates of neonatal sepsis burden vary by setting. Differing estimates of disease burden have been reported from high-income countries compared with reports from low-income and middle-income countries. The clinical manifestations range from subclinical infection to severe manifestations of focal or systemic disease. The source of the pathogen might be attributed to an in-utero infection, acquisition from maternal flora, or postnatal acquisition from the hospital or community. The timing of exposure, inoculum size, immune status of the infant, and virulence of the causative agent influence the clinical expression of neonatal sepsis. Immunological immaturity of the neonate might result in an impaired response to infectious agents. This is especially evident in premature infants whose prolonged stays in hospital and need for invasive procedures place them at increased risk for hospital-acquired infections. Clinically, there is often little difference between sepsis that is caused by an identified pathogen and sepsis that is caused by an unknown pathogen. Culture-independent diagnostics, the use of sepsis prediction scores, judicious antimicrobial use, and the development of preventive measures including maternal vaccines are ongoing efforts designed to reduce the burden of neonatal sepsis.