Biomarker Enrichment in Sepsis-Associated Acute Kidney Injury: Finding High-Risk Patients in the Intensive Care Unit.

BACKGROUND: Sepsis-associated acute kidney injury (AKI) is a leading comorbidity in admissions to the intensive care unit. While a gold standard definition exists, it remains imperfect and does not allow for the timely identification of patients in the setting of critical illness. This review will discuss the use of biochemical and electronic biomarkers to allow for prognostic and predictive enrichment of patients with sepsis-associated AKI over and above the use of serum creatinine and urine output. SUMMARY: Current data suggest that several biomarkers are capable of identifying patients with sepsis at risk for the development of severe AKI and other associated morbidity. This review discusses these data and these biomarkers in the setting of sub-phenotyping and endotyping sepsis-associated AKI. While not all these tests are widely available and some require further validation, in the near future we anticipate several new tools to help nephrologists and other providers better care for patients with sepsis-associated AKI. KEY MESSAGES: Predictive and prognostic enrichment using both traditional biomarkers and novel biomarkers in the setting of sepsis can identify subsets of patients with either similar outcomes or similar pathophysiology, respectively. Novel biomarkers can identify kidney injury in patients without consensus definition AKI (e.g., changes in creatinine or urine output) and can predict other adverse outcomes (e.g., severe consensus definition AKI, inpatient mortality). Finally, emerging artificial intelligence and machine learning-derived risk models are able to predict sepsis-associated AKI in critically ill patients using advanced learning techniques and several laboratory and vital sign measurements.

Fetal chronic hypoxia does not affect urinary presepsin levels in newborns at birth.

OBJECTIVES: Early sepsis detection and diagnosis still constitutes an open issue since the accuracy of standard-of care parameters is biased by a series of perinatal factors including hypoxia. Therefore, we aimed at investigating the effect of fetal chronic hypoxia insult on urine levels of a promising new marker of sepsis, namely presepsin (P-SEP). METHODS: We conducted a prospective case-control study in 22 cases of early-intrauterine growth restriction (E-IUGR) compared with 22 small-for-gestational-age (SGA) newborns and 66 healthy controls. P-SEP urine samples were collected over the first 72 h from birth. Blood culture and C-reactive protein (CRP) blood levels were measured in E-IUGR and SGA infants. Perinatal standard monitoring parameters and main outcomes were also recorded. RESULTS: No significant urinary P-SEP differences (p>0.05, for all) were observed among studied groups. Moreover, no significant correlations (p>0.05, for both) between urinary P-SEP and blood CRP levels in both E-IUGR and SGA groups (R=0.08; R=0.07, respectively) were observed. CONCLUSIONS: The present results showing the lack of influence of fetal chronic hypoxia on urinary P-SEP levels offer additional data to hypothesize the possible use of urinary P-SEP measurement in neonates in daily clinical practice. Further multicenter prospective data are needed, including infants with early-onset sepsis.

Predictive performance of two types of urinary biomarkers for renal non-recovery in sepsis-associated acute kidney injury: a prospective observational study.

BACKGROUND AND PURPOSE: Renal non-recovery is known to have negative prognostic implications in patients suffering from acute kidney injury (AKI). Nevertheless, the identification of biomarkers for predicting renal non-recovery in sepsis-associated AKI (SA-AKI) within clinical settings remains unresolved. This study aims to evaluate and compare the predictive ability for renal non-recovery, use of kidney replacement therapy (KRT) in the Intensive Care Unit (ICU), and 30-day mortality after SA-AKI by two urinary biomarkers, namely C-C motif chemokine ligand 14 (CCL14) and [TIMP-2]•[IGFBP7]. METHODS: We prospectively screened adult patients who met the criteria for AKI stage 2-3 and Sepsis-3.0 in two ICUs from January 2019 to May 2022. Patients who developed new-onset SA-AKI after ICU admission were enrolled and urinary biomarkers including [TIMP-2]•[IGFBP7] and CCL14 were detected at the time of SA-AKI diagnosis. The primary endpoint was non-recovery from SA-AKI within 7 days. The secondary endpoints were the use of KRT in the ICU and 30-day mortality after SA-AKI. The individual discriminative ability of [TIMP-2]•[IGFBP7] and CCL14 to predict renal non-recovery were evaluated by the area under receiver operating characteristics curve (AUC). RESULTS: 141 patients with stage 2-3 SA-AKI were finally included, among whom 54 (38.3%) experienced renal non-recovery. Urinary CCL14 exhibited a higher predictive capability for renal non-recovery compared to [TIMP-2]•[IGFBP7], with CCL14 showing an AUC of 0.901, versus an AUC of 0.730 for [TIMP-2]•[IGFBP7] (P = 0.001). Urinary CCL14 and [TIMP-2]•[IGFBP7] demonstrated a moderate predictive value for the need for KRT in ICU, with AUC values of 0.794 and 0.725, respectively; The AUC of [TIMP-2]•[IGFBP7] combined with CCL14 reached up to 0.816. Urinary CCL14 and [TIMP-2]•[IGFBP7] exhibited poor predictive power for 30-day mortality, with respective AUC values of 0.623 and 0.593. CONCLUSION: Urinary CCL14 had excellent predictive value for renal non-recovery in SA-AKI patients. For predicting the use of KRT in the ICU, the predictive capability of urinary [TIMP-2]•[IGFBP7] or CCL14 was fair. However, a combination of [TIMP-2]•[IGFBP7] and CCL14 showed good predictive ability for the use of KRT.

Combining renal cell arrest and damage biomarkers to predict progressive AKI in patient with sepsis.

BACKGROUND: Sepsis is the most common trigger for AKI and up to 40% of mild or moderate septic AKI would progress to more severe AKI, which is associated with significantly increased risk for death and later CKD/ESRD. Early identifying high risk patients for AKI progression is a major challenge in patients with septic AKI. METHODS: This is a prospective, multicenter cohort study which enrolled adult patients with sepsis and initially developed stage 1 or 2 AKI in the intensive care unit from January 2014 to March 2018. AKI was diagnosed and staged according to 2012 KDIGO-AKI guidelines. Renal cell arrest biomarkers (urinary TIMP2*IGFBP7, u[TIMP-2]*[IGFBP7]) and renal damage biomarkers (urinary KIM-1[uKIM-1] and urinary IL-18 [uIL-18]) were measured at time of AKI clinical diagnosis, and the performance of biomarkers for predicting septic AKI progression alone or in combination were evaluated. The primary outcome was AKI progression defined as worsening of AKI stage. The secondary outcome was AKI progression with subsequent death during hospitalization. RESULTS: Among 433 screened patients, 149 patients with sepsis and stage 1 or 2 AKI were included, in which 63 patients developed progressive AKI and 49 patients subsequently died during hospitalization. u[TIMP-2]*[IGFBP7], uKIM-1 and uIL-18 independently predicted the progression of septic AKI in which u[TIMP-2]*[IGFBP7] showed the greatest AUC (0.745; 95%CI, 0.667-0.823) as compared to uKIM-1 (AUC 0.719; 95%CI 0.638-0.800) and uIL-18 (AUC 0.619; 95%CI 0.525-0.731). Combination of u[TIMP-2]*[IGFBP7] with uKIM-1 improved the performance of predicting septic AKI progression with AUC of 0.752. u[TIMP-2]*[IGFBP7], alone or combined with uKIM-1/uIL-18, improved the risk reclassification over the clinical risk factor model alone both for the primary and secondary outcomes, as evidenced by significant category-free net reclassification index. CONCLUSIONS: Combination of renal cell arrest and damage biomarkers enhanced the prediction of AKI progression in patients with sepsis and improved risk reclassification over the clinical risk factors.

The evaluation of early predictive factors for urosepsis in patients with negative preoperative urine culture following mini-percutaneous nephrolithotomy.

PURPOSE: To identify early predictive factors for urosepsis secondary to mini-percutaneous nephrolithotomy (MPCNL) in patients with negative preoperative urine culture (UC). METHODS: A total of 786 patients with baseline negative UC who underwent MPCNL between January 2017 and June 2019 were retrospectively analyzed. Urosepsis was defined according to the Sepsis-3 definition. Subsequently, perioperative potential risk factors were compared between non-urosepsis and urosepsis groups. RESULTS: Despite negative UC in all patients, the rate of positive stone culture (SC) was 16.0%; the rate of pelvic urine culture (PUC) was 7.5%; 23 cases (2.9%) developed urosepsis after MPCNL. Univariate analysis showed that urosepsis was associated with the female gender, BMI, stone burden, diabetes mellitus and preoperative urine test. Multivariate logistic regression analysis suggested that urine test with positive nitrite and white blood cells and leukocyte esterase (N+WBC+LE+) (OR 17.51, 95% CI 6.75-45.38, P < 0.001) and operative time > 120 min (OR 3.53, 95% CI 1.41-8.85, P = 0.007) were independent risk factors for urosepsis. Additionally, receiver operating characteristic curve analysis of N+WBC+LE+ showed that the area under the curve was 0.785 for predicting the occurrence of urosepsis. Further analysis showed that N+WBC+LE+ provided an efficient prediction of SC+/PUC+ (SC+ or PUC+) with 61.7% sensitivity and 97.3% specificity. CONCLUSIONS: In spite of the baseline negative preoperative UC, 2.9% of patients developed urosepsis after MPCNL. N+WBC+LE + was determined to be an early and efficient prediction of intraoperative bacterial status and urosepsis following MPCNL. Nevertheless, further studies are needed to confirm the results.

Effect of Furosemide on Urinary Oxygenation in Patients with Septic Shock.

BACKGROUND: Renal medullary hypoxia precedes the development of acute kidney injury in experimental sepsis and can now be assessed by continuous measurement of urinary oxygen tension (PuO2). OBJECTIVES: We aimed to test if PuO2 measurements in patients with septic shock would be similar to those shown in experimental sepsis and would detect changes induced by the administration of furosemide. METHOD: Pilot prospective observational cohort study in a tertiary intensive care unit (ICU). Seven adult patients with septic shock admitted to ICU had PuO2 measurements recorded minutely. There were 29 episodes of intravenous furosemide (20 mg n = 19; 40 mg n = 10). RESULTS: The median pre-furosemide PuO2 was low at 21.2 mm Hg (interquartile range [IQR] 17.73-24.86) and increased to 26 mm Hg (IQR 20.27-29.95) at 20 min (p < 0.01), to 27.5 mm Hg (IQR 24.06-33.18) at 40 min (p < 0.01) and to 28.5 mm Hg (IQR 22.65-31.03) at 60 min (p < 0.01). The increase in PuO2 was greater in episodes with a diuretic response >2 mL/kg/h than during episodes without such a response (p < 0.01). CONCLUSIONS: PuO2 measurements in patients are reflective of the low values reported in experimental models of sepsis. PuO2 values increased following furosemide administration with a response independently associated with greater diuresis.

Urinary Oxygenation as a Surrogate Measure of Medullary Oxygenation During Angiotensin II Therapy in Septic Acute Kidney Injury.

OBJECTIVES: Angiotensin II is an emerging therapy for septic acute kidney injury, but it is unknown if its vasoconstrictor action induces renal hypoxia. We therefore examined the effects of angiotensin II on intrarenal PO2 in ovine sepsis. We also assessed the validity of urinary PO2 as a surrogate measure of medullary PO2. DESIGN: Interventional study. SETTING: Research Institute. SUBJECTS: Sixteen adult Merino ewes (n = 8/group). INTERVENTIONS: Sheep were instrumented with fiber-optic probes in the renal cortex, medulla, and within a bladder catheter to measure PO2. Conscious sheep were infused with Escherichia coli for 32 hours. At 24-30 hours, angiotensin II (0.5-33.0 ng/kg/min) or saline vehicle was infused. MEASUREMENTS AND MAIN RESULTS: Septic acute kidney injury was characterized by hypotension and a 60% ± 6% decrease in creatinine clearance. During sepsis, medullary PO2 decreased from 36 ± 1 to 30 ± 3 mm Hg after 1 hour and to 20 ± 2 mm Hg after 24 hours; at these times, urinary PO2 was 42 ± 2, 34 ± 2, and 23 ± 2 mm Hg. Increases in urinary neutrophil gelatinase-associated lipocalin (12% ± 3%) and serum creatinine (60% ± 23%) were only detected at 8 and 24 hours, respectively. IV infusion of angiotensin II, at 24 hours of sepsis, restored arterial pressure and improved creatinine clearance, while not exacerbating medullary or urinary hypoxia. CONCLUSIONS: In septic acute kidney injury, renal medullary and urinary hypoxia developed several hours before increases in currently used biomarkers. Angiotensin II transiently improved renal function without worsening medullary hypoxia. In septic acute kidney injury, angiotensin II appears to be a safe, effective therapy, and urinary PO2 may be used to detect medullary hypoxia.

Sequential Analysis of a Panel of Biomarkers and Pathologic Findings in a Resuscitated Rat Model of Sepsis and Recovery.

OBJECTIVES: To characterize the temporal pattern of a panel of blood and urinary biomarkers in an animal model of fecal peritonitis and recovery. DESIGN: Prospective observational animal study. SETTING: University research laboratory. SUBJECTS: Male Wistar rats. INTERVENTIONS: A fluid-resuscitated, long-term (3 d) rat model of sepsis (fecal peritonitis) and recovery was used to understand the temporal association of sepsis biomarkers in relation to systemic hemodynamics, inflammation, and renal function. At predefined time points (3, 6, 12, 24, 48, 72 hr), animals (≥ 6 per group) underwent echocardiography, blood and urine sampling, and had kidneys taken for histological analysis. Comparison was made against sham-operated controls and naïve animals. MEASUREMENTS AND MAIN RESULTS: The systemic proinflammatory response was maximal at 6 hours, corresponding with the nadir of stroke volume. Serum creatinine peaked late (24 hr), when clinical recovery was imminent. Histological evidence of tubular injury and cell death was minimal. After a recovery period, all biomarkers returned to levels approaching those observed in sham animals. Apart from urine clusterin and interleukin-18, all other urinary biomarkers were elevated at earlier time points compared with serum creatinine. Urine neutrophil gelatinase-associated lipocalin was the most sensitive marker among those studied, rising from 3 hours. While serum creatinine fell at 12 hours, serum cystatin C increased, suggestive of decreased creatinine production. CONCLUSIONS: Novel information is reported on the temporal profile of a panel of renal biomarkers in sepsis in the context of systemic and renal inflammation and recovery. Insight into the pathophysiology of acute kidney injury is gleaned from the temporal change markers of renal injury (urine neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, calbindin), followed by a marker of cell cycle arrest (urine insulin-like growth factor-binding protein 7) and, finally, by functional markers of filtration (serum creatinine and cystatin C). These clinically relevant findings should have significant influence on future clinical testing.

Impaired systemic tetrahydrobiopterin bioavailability and increased dihydrobiopterin in adult falciparum malaria: association with disease severity, impaired microvascular function and increased endothelial activation.

Tetrahydrobiopterin (BH4) is a co-factor required for catalytic activity of nitric oxide synthase (NOS) and amino acid-monooxygenases, including phenylalanine hydroxylase. BH4 is unstable: during oxidative stress it is non-enzymatically oxidized to dihydrobiopterin (BH2), which inhibits NOS. Depending on BH4 availability, NOS oscillates between NO synthase and NADPH oxidase: as the BH4/BH2 ratio decreases, NO production falls and is replaced by superoxide. In African children and Asian adults with severe malaria, NO bioavailability decreases and plasma phenylalanine increases, together suggesting possible BH4 deficiency. The primary three biopterin metabolites (BH4, BH2 and B0 [biopterin]) and their association with disease severity have not been assessed in falciparum malaria. We measured pterin metabolites in urine of adults with severe falciparum malaria (SM; n=12), moderately-severe malaria (MSM, n=17), severe sepsis (SS; n=5) and healthy subjects (HC; n=20) as controls. In SM, urinary BH4 was decreased (median 0.16 »mol/mmol creatinine) compared to MSM (median 0.27), SS (median 0.54), and HC (median 0.34)]; p<0.001. Conversely, BH2 was increased in SM (median 0.91 »mol/mmol creatinine), compared to MSM (median 0.67), SS (median 0.39), and HC (median 0.52); p<0.001, suggesting increased oxidative stress and insufficient recycling of BH2 back to BH4 in severe malaria. Overall, the median BH4/BH2 ratio was lowest in SM [0.18 (IQR: 0.04-0.32)] compared to MSM (0.45, IQR 0.27-61), SS (1.03; IQR 0.54-2.38) and controls (0.66; IQR 0.43-1.07); p<0.001. In malaria, a lower BH4/BH2 ratio correlated with decreased microvascular reactivity (r=0.41; p=0.03) and increased ICAM-1 (r=-0.52; p=0.005). Decreased BH4 and increased BH2 in severe malaria (but not in severe sepsis) uncouples NOS, leading to impaired NO bioavailability and potentially increased oxidative stress. Adjunctive therapy to regenerate BH4 may have a role in improving NO bioavailability and microvascular perfusion in severe falciparum malaria.

Urinary orosomucoid: a novel, early biomarker of sepsis with promising diagnostic performance.

BACKGROUND: In order to help clinical decision making, we investigated the diagnostic and prognostic ability of urinary orosomucoid (u-ORM) as a new sepsis biomarker, and compared its performance to classical inflammatory parameters. METHODS: We monitored u-ORM in septic (n=43) and SIRS (n=13) patients in a 5-day follow-up study vs. control patients (n=30). U-ORM was measured by a newly developed turbidimetric assay. U-ORM values were referred to urinary creatinine and expressed as u-ORM/u-CREAT (mg/mmol). RESULTS: Significantly higher (p<0.001) u-ORM/u-CREAT levels were found in sepsis than in SIRS. Both intensive care unit (ICU) groups showed strongly elevated values compared to controls (p<0.001). The medians of admission u-ORM/u-CREAT levels were 19.2 in sepsis, 2.1 in SIRS and 0.2 mg/mmol in controls. The area under the receiver operating characteristic curve for distinguishing SIRS from sepsis was found to be 0.954 for u-ORM/u-CREAT, superior to serum ORM and hsCRP. U-ORM levels did not change during the 5-day follow-up and were independent of the severity of sepsis however, we found extremely elevated u-ORM/u-CREAT values in dialyzed septic patients (52.2 mg/mmol as median). CONCLUSIONS: The early and relevant increase of u-ORM in sepsis suggests that it might be a promising novel marker of sepsis and could be a valuable part of routine laboratory and clinical practice.

Urinary exosomal activating transcriptional factor 3 as the early diagnostic biomarker for sepsis-induced acute kidney injury.

BACKGROUND: An early sepsis-induced acute kidney injury (sepsis-AKI) biomarker is currently in needed. Urinary neutrophil gelatinase-associated lipocalin (uNGAL) is a candidate of sepsis-AKI biomarker but with different cut-point values. Urinary exosomal activating transcriptional factor 3 (uATF3) has been mentioned as an interesting biomarker. METHODS: We conducted experiments in mice and a prospective, multicenter study in patients as a proof of concept that urine exosome is an interesting biomarker. An early expression of ATF3 in kidney of CD-1 mice at 6 h after cecal ligation and puncture implied the possibility of uATF3 as an early sepsis-AKI biomarker. Increase serum creatinine (Scr) ≥0.3 mg/dL from the baseline was used as an AKI diagnosis and urine was analyzed for uATF3 and uNGAL. Patients with baseline Scr at admission ≥1.5 mg/dL were excluded. RESULTS: The analysis showed higher Scr, uNGAL and uATF3 in patients with sepsis-AKI in comparison with patients with sepsis-non-AKI and healthy volunteers. A fair correlation, r2 = 0.47, between uATF3 and uNGAL was showed in sepsis-AKI group with Scr ≥2 mg/dL. To see if uATF3 could be an early sepsis-AKI biomarker, urine sample was collected daily during the first week of the admission. In sepsis-AKI and sepsis-non-AKI groups, uNGAL were 367 ± 43 ng/mL and 183 ± 23 ng/mL, respectively; and uATF3 were 19 ± 4 ng/mL and 1.4 ± 0.8 ng/mL, respectively. With the mean value of uNGAL and uATF3 in sepsis AKI as a cut-off level, AUROC of uNGAL and uATF3 were 64% (95% CI 0.54 to 0.74) and 84% (95% CI 0.77 to 0.91), respectively. CONCLUSIONS: Urine exosome is an interesting source of urine biomarker and uATF3 is an interesting sepsis-AKI biomarker.

Urinary neprilysin in the critically ill patient.

BACKGROUND: Critically ill patients in intensive care face hazardous conditions. Among these, acute kidney injury (AKI) is frequently seen as a result of sepsis. Early diagnosis of kidney injury is of the utmost importance in the guidance of interventions or avoidance of treatment-induced kidney injury. On these grounds, we searched for markers that could indicate proximal tubular cell injury. METHODS: Urine samples of 90 patients admitted to the intensive or intermediate care unit were collected over 2 to 5 days. The biomarker neprilysin (NEP) was investigated in urine using several methods such as dot blot, ELISA and immunofluorescence of urinary casts. Fifty-five healthy donors acted as controls. RESULTS: NEP was highly significantly elevated in the urine of patients who suffered AKI according to the KDIGO criteria in comparison to healthy controls. It was also found to be elevated in ICU patients without overt signs of AKI according to serum creatinine changes, however they were suffering from potential nephrotoxic insults. According to our findings, urinary NEP is indicative of epithelial cell alterations at the proximal tubule. This was elaborated in ICU patients when ghost fragments and NEP+ microvesicles were observed in urinary sediment cytopreparations. Furthermore, NEP+ immunofluorescence of healthy kidney tissue showed staining at the proximal tubules. CONCLUSIONS: NEP, a potential marker for proximal tubular epithelia, can be measured in urine. This does not originate from leakage of elevated serum levels, but indicates proximal tubular cell alterations such as brush border severing, which can heal in most cases.

Urinary Tissue Inhibitor of Metalloproteinase-2 and Insulin-Like Growth Factor-Binding Protein 7 for Risk Stratification of Acute Kidney Injury in Patients With Sepsis.

OBJECTIVES: To examine the performance of the urinary biomarker panel tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 in patients with sepsis at ICU admission. To investigate the effect of nonrenal organ dysfunction on tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 in this population. METHOD: In this ancillary analysis, we included patients with sepsis who were enrolled in either of two trials including 39 ICUs across Europe and North America. The primary endpoint was moderate-severe acute kidney injury (equivalent to Kidney Disease Improving Global Outcome stage 2-3) within 12 hours of enrollment. We assessed biomarker performance by calculating the area under the receiver operating characteristic curve, sensitivity, specificity, and negative and positive predictive values at three cutoffs: 0.3, 1.0, and 2.0 (ng/mL)/1,000. We also calculated nonrenal Sequential Organ Failure Assessment scores for each patient on enrollment and compared tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 results in patients with and without acute kidney injury and across nonrenal Sequential Organ Failure Assessment scores. Finally, we constructed a clinical model for acute kidney injury in this population and compared the performance of the model with and without tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7. RESULTS: We included 232 patients in the analysis and 40 (17%) developed acute kidney injury. We observed significantly higher urine tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 in patients with acute kidney injury than without acute kidney injury in both patients with low and high nonrenal Sequential Organ Failure Assessment scores (p < 0.001). The area under the receiver operating characteristic curve (95% CI) of tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 was 0.84 (0.73-0.92) and 0.85 (0.76-0.94), in low and high nonrenal Sequential Organ Failure Assessment score subgroups. Performance of the tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 test was not modified by nonrenal Sequential Organ Failure Assessment (p = 0.70). In multivariate analysis, the addition of tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 significantly improved the performance of a clinical model for predicting acute kidney injury (p = 0.015). CONCLUSION: Urinary tissue inhibitor of metalloproteinase-2 and insulin-like growth factor-binding protein 7 accurately predicts acute kidney injury in septic patients with or without other organ failures.

Diagnostic methods to determine microbiology of postpartum endometritis in South Asia: laboratory methods protocol used in the Postpartum Sepsis Study: a prospective cohort study.

BACKGROUND: The South Asian region has the second highest risk of maternal death in the world. To prevent maternal deaths due to sepsis and to decrease the maternal mortality ratio as per the World Health Organization Millenium Development Goals, a better understanding of the etiology of endometritis and related sepsis is required. We describe microbiological laboratory methods used in the maternal Postpartum Sepsis Study, which was conducted in Bangladesh and Pakistan, two populous countries in South Asia. METHODS/DESIGN: Postpartum maternal fever in the community was evaluated by a physician and blood and urine were collected for routine analysis and culture. If endometritis was suspected, an endometrial brush sample was collected in the hospital for aerobic and anaerobic culture and molecular detection of bacterial etiologic agents (previously identified and/or plausible). DISCUSSION: The results emanating from this study will provide microbiologic evidence of the etiology and susceptibility pattern of agents recovered from patients with postpartum fever in South Asia, data critical for the development of evidence-based algorithms for management of postpartum fever in the region.

Urinary L-FABP as a mortality predictor in <5-year-old children with sepsis in Bangladesh.

BACKGROUND: Although sepsis is often associated with high mortality in severely malnourished children, data are very limited on appropriate diagnostic tools to predict mortality. We examined the role of urinary liver-type fatty acid-binding protein (L-FABP) in children <5 years old with sepsis who died. METHODS: This prospective observational study was conducted at the Dhaka Hospital of the International Centre for Diarrhoeal Disease Research, Bangladesh. Children aged 6-59 months admitted with sepsis from April 2010 to December 2011 were enrolled. Comparison of clinical and laboratory characteristics was made between children who survived (n = 83) and those who did not survive (n = 22). RESULTS: On multiple Poisson regression analysis, after adjusting for potential confounders such as mid-upper arm circumference < 115 mm, plasma albumin < 2.5 g/dL, potassium > 5.0 mmol/L, and blood urea nitrogen > 20 mg/dL on admission, first urine L-FABP ≥ 370 ng/mL (relative risk [RR], 2.76; 95%CI: 1.22-6.25), weight-for-length/height z score < -3 (RR, 2.54; 95%CI: 1.26-5.09), capillary refilling time > 2.0 s (RR, 5.16; 95%CI: 1.46-18.3), and sodium > 160 mmol/L (RR, 2.72; 95%CI: 1.07-6.90) were identified as significant risk factors of mortality in children with sepsis. Diagnostic performance of first urine L-FABP was analyzed using receiver operating characteristic curve, and the area under the curve was 0.647 (95%CI: 0.500-0.795). CONCLUSION: Urinary L-FABP may be a useful predictor of mortality in septic children. Urinary examination is non-invasive and easy to apply at the bedside.

Urinary neutrophil gelatinase-associated lipocalin: potential biomarker for late-onset sepsis.

BACKGROUND: To assess the ability of urinary neutrophil gelatinase-associated lipocalin (UNGAL) to discriminate between culture-positive vs. culture-negative late-onset sepsis evaluations. METHODS: This is a prospective observational study of 136 neonates who underwent ≥1 sepsis evaluation at >72 h of age. Urine was obtained at the time of sepsis evaluation to measure UNGAL concentration. Using generalized estimating equations controlling for gender, gestational and postnatal age, acute kidney injury, and within-patient correlations, pair-wise contrasts between mean log UNGAL concentrations of infants with negative sepsis evaluations vs. culture-positive sepsis and presumed sepsis were assessed. Discrimination characteristics at several UNGAL cutoff concentrations were assessed using receiver-operating characteristic curves. RESULTS: The predicted mean log UNGAL values of culture-positive sepsis and presumed sepsis vs. negative sepsis evaluations differed significantly (P < 0.001 and P = 0.02, respectively). At a cutoff ≥ 50 ng/ml, UNGAL discriminated between culture-positive sepsis and culture-negative sepsis evaluations with sensitivity = 86%, specificity = 56%, positive predictive value = 41%, negative predictive value = 92%, and number needed to treat = 3. CONCLUSION: UNGAL is a noninvasive biomarker with high negative predictive value at the time of late-onset sepsis evaluation in neonates and could be a useful adjunct to traditional components of sepsis evaluations.

Diagnostic value of neutrophil gelatinase-associated lipocalin, cystatin C, and soluble triggering receptor expressed on myeloid cells-1 in critically ill patients with sepsis-associated acute kidney injury.

INTRODUCTION: Neutrophil gelatinase-associated lipocalin (NGAL), cystatin C (Cys-C), and soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) are novel diagnostic biomarkers of acute kidney injury (AKI). We aimed to determine the diagnostic properties of these biomarkers for detecting AKI in critically ill patients with sepsis. METHODS: We divided 112 patients with sepsis into non-AKI sepsis (n = 57) and AKI sepsis (n = 55) groups. Plasma and urine specimens were collected on admission and every 24 hours until 72 hours and tested for NGAL, Cys-C, and TREM-1 concentrations. Their levels were compared on admission, at diagnosis, and 24 hours before diagnosis. RESULTS: Both plasma and urine NGAL, Cys-C, and sTREM-1 were significantly associated with AKI development in patients with sepsis, even after adjustment for confounders by using generalized estimating equations. Compared with the non-AKI sepsis group, the sepsis AKI group exhibited markedly higher levels of these biomarkers at diagnosis and 24 hours before AKI diagnosis (P < 0.01). The diagnostic and predictive values of plasma and urine NGAL were good, and those of plasma and urine Cys-C and sTREM-1 were fair. CONCLUSION: Plasma and urine NGAL, Cys-C, and sTREM-1 can be used as diagnostic and predictive biomarkers for AKI in critically ill patients with sepsis.

Randomized controlled trial of calcitriol in severe sepsis.

RATIONALE: Vitamin D and its metabolites have potent immunomodulatory effects in vitro, including up-regulation of cathelicidin, a critical antimicrobial protein. OBJECTIVES: We investigated whether administration of 1,25-dihydroxyvitamin D (calcitriol) to critically ill patients with sepsis would have beneficial effects on markers of innate immunity, inflammation, and kidney injury. METHODS: We performed a double-blind, randomized, placebo-controlled, physiologic study among 67 critically ill patients with severe sepsis or septic shock. Patients were randomized to receive a single dose of calcitriol (2 µg intravenously) versus placebo. The primary outcome was plasma cathelicidin protein levels assessed 24 hours after study drug administration. Secondary outcomes included leukocyte cathelicidin mRNA expression, plasma cytokine levels (IL-10, IL-6, tumor necrosis factor-α, IL-1ß, and IL-2), and urinary kidney injury markers. MEASUREMENTS AND MAIN RESULTS: Patients randomized to calcitriol (n = 36) versus placebo (n = 31) had similar plasma cathelicidin protein levels at 24 hours (P = 0.16). Calcitriol-treated patients had higher cathelicidin (P = 0.04) and IL-10 (P = 0.03) mRNA expression than placebo-treated patients 24 hours after study drug administration. Plasma cytokine levels (IL-10, IL-6, tumor necrosis factor-α, IL-1ß, and IL-2) and urinary kidney injury markers were similar in calcitriol- versus placebo-treated patients (P > 0.05 for all comparisons). Calcitriol had no effect on clinical outcomes nor were any adverse effects observed. CONCLUSIONS: Calcitriol administration did not increase plasma cathelicidin protein levels in critically ill patients with sepsis and had mixed effects on other immunomodulatory markers. Additional phase II trials investigating the dose and timing of calcitriol as a therapeutic agent in specific sepsis phenotypes may be warranted. Clinical trial registered with www.clinicaltrials.gov (NCT 01689441).

Influence of severity of illness on neutrophil gelatinase-associated lipocalin performance as a marker of acute kidney injury: a prospective cohort study of patients with sepsis.

BACKGROUND: The role of neutrophil gelatinase-associated lipocalin (NGAL) as a diagnostic marker for acute kidney injury (AKI) in sepsis is still debated. We hypothesized that in sepsis, the performance of serum(s) and urinary(u) NGAL can be negatively impacted by severity of illness and inflammation, and that both uNGAL and sNGAL levels can be increased regardless of presence of AKI. METHODS: One hundred and seven patients with sepsis were included. uNGAL and sNGAL were measured at admission (T0) and 4 hours (T4) and 24 hours later (T24). Transient and intrinsic AKI were respectively defined as AKI according to RIFLE during the first 72 hours that did or did not recover to "no AKI" in the following 72 hours. Patients were classified according to tertiles of CRP and APACHE II score increase. The relationship between sNGAL and uNGAL was assessed by linear regression. RESULTS: Fifty-seven patients developed transient and 22 intrinsic AKI. Prevalence of transient and intrinsic AKI were higher in patients with versus without septic shock (OR (95% CI): 3.3(1.4-8.2)). uNGAL was associated with sNGAL, and this with parallel slopes but different intercepts for AKI (Y = 0.87*X + 314.3, R2 = 0.31) and no AKI (Y = 0.87*X + 20.1, R2 = 0.38). At T4, median uNGAL and sNGAL levels were higher in septic patients with versus without shock but this is independent of AKI ((545 ng/mL vs 196 ng/ml for uNGAL and 474 ng/ml vs 287 ng/ml for sNGAL (both P = 0.003)). Both uNGAL and sNGAL levels increased with tertiles of CRP and APACHE II score increase. CONCLUSIONS: Serum and uNGAL levels are influenced by severity of illness and inflammation, and this was found to be independent of the presence of AKI. There is a strong correlation between sNGAL and uNGAL levels in patients with sepsis, indicating that increased levels of uNGAL can also be due to overspill from the systemic circulation, blurring the discriminative value of NGAL as a biomarker for AKI in patients with sepsis.

Glucosuria as an early marker of late-onset sepsis in preterms: a prospective cohort study.

BACKGROUND: Early and accurate diagnosis of late-onset sepsis (LONS) in preterm infants is difficult since presenting signs are subtle and non-specific. Because neonatal sepsis may be accompanied by glucose intolerance and glucosuria, we hypothesized that glucosuria may be associated with LONS in preterms, in an early stage. We aim to evaluate the association of glucosuria and late-onset neonatal sepsis (LONS) in preterm infants, in an attempt to improve early and accurate diagnosis of LONS. METHODS: We performed a prospective observational cohort study in 316 preterms (<34 weeks). We daily measured glucosuria and followed patients for occurrence of LONS, defined as clinical and blood culture-proven sepsis occurring after 72 h. Attending physicians were blinded to glucosuria results. We assessed the diagnostic value of glucosuria for clinical and blood culture-proven LONS using logistic regression analysis. RESULTS: Glucosuria was found in 65.8% of 316 preterm patients, and sepsis was suspected 157 times in 123 patients. LONS was found in 47.1% of 157 suspected episodes. The presence of glucosuria was associated with LONS (OR 2.59, 95% CI 1.24-5.43, p = 0.012) with sensitivity 69.0% and specificity 53.8% (Likelihoodratio 1.49). After adjustment for gestational age, birth weight, and postnatal age, this association weakened and was no longer significant (adjusted OR 2.16; 95% CI 0.99-1.85, p = 0.055). An increase in glucosuria 48-24 h before onset of symptoms was not associated with LONS. CONCLUSION: In preterms glucosuria is associated with LONS within 24 h, however this association is too weak to be of diagnostic value.