Diagnosis of bacterial urinary tract infection: Utility of urine myeloperoxidase concentration to predict urine culture results in dogs.

Suspected bacterial urinary tract infections (UTI) are a common cause of overuse and misuse of antimicrobials. A bedside diagnostic test that could accurately predict urine culture results would prevent antimicrobial overuse, but accurate biomarkers have not yet been identified in veterinary medicine. The objective of this study was to evaluate urine myeloperoxidase (uMPO) as a rapidly available, accurate marker to predict urine culture results. We hypothesized that uMPO would be higher in dogs with a positive urine culture than in dogs with a negative urine culture, and that uMPO could be used to aid in the accurate diagnosis of significant bacteriuria. Urine samples were collected from a veterinary university clinical pathology lab. uMPO concentration was measured using a commercially available canine myeloperoxidase (MPO) enzyme-linked immunosorbent assay (ELISA). Following validation, samples from 98 dogs that had a urinalysis and urine culture performed as part of their diagnostic investigation were included. Forty-seven dogs had a negative urine culture and fifty-one dogs had a positive urine culture. uMPO levels were significantly higher in samples that had a positive culture (median 2.13 ng/ml; IQR 0.98-7.07) versus samples that had a negative culture (median 1.07 ng/ml; IQR 0.52-1.84)(p < 0.005). Based on receiver-operator characteristic, a cutoff of 0.55 ng/ml was chosen to maximize sensitivity and specificity. Using a cutoff of 0.55 ng/ml, uMPO had a sensitivity of 70% and specificity of 69% to determine the presence of a positive culture. However, the degree of overlap between groups may preclude the use of this test as a surrogate for urine culture in a clinical setting.

Urinary mitochondrial DNA is a useful biomarker for assessing kidney injury of antineutrophil cytoplasmic antibody -associated vasculitis.

BACKGROUND: The value of urinary mitochondrial DNA (mtDNA) for assessing kidney injury of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) was investigated. METHODS: Thirty-nine kidney biopsy-proved myeloperoxidase (MPO)-ANCA associated AAV patients were enrolled and analyzed. RESULTS: The average urinary mtDNA of patients was significantly higher than that of normal controls (3372.74 ± 1859.72 vs. 474.90 ± 123.59 copy/nmol creatinine, p < 0.001). The patients who needed dialysis at disease onset had the highest levels of urinary mtDNA (5072.23 ± 1302.87 copy/nmol creatinine). Urinary mtDNA positively correlated with urinary neutrophil gelatinase-associated lipocalin (R = 0.661, P < 0.001) and negatively correlated with estimated glomerular filtration rate (R = -0.515, P = 0.001). The urinary mtDNA level of crescentic class (4703.08 ± 1744.31 copy/nmol creatinine) was higher than that of mixed class (3258.14 ± 1158.99 copy/nmol creatinine) and focal class (2268.15 ± 1897.63 copy/nmol creatinine). Univariate correlation analysis showed urinary mtDNA positively correlated with interstitial neutrophils (R = 0.471, P = 0.048) and glomerular neutrophils (R = 0.673, P = 0.002) in kidney biopsy. Among 13 patients who needed hemodialysis at disease onset, 10 patients who got renal recovery had higher urinary mtDNA than 3 patients who remained dialysis dependent (5455.20 ± 1174.64 vs. 3795.67 ± 893.34 copy/nmol creatinine, p = 0.047). CONCLUSIONS: Urinary mtDNA increases in AAV with kidney injury, and its levels correlate with the severity of kidney injury and neutrophils infiltration in pathology.

Urinary Myeloperoxidase to Creatinine Ratio as a New Marker for Diagnosis of Urinary Tract Infection.

Objective To determine whether urinary myeloperoxidase to creatinine ratio (MCR) can serve as a marker for diagnosis of urinary tract infection (UTI).Methods Patients suspected of UTI were consecutively enrolled and further divided into the culture positive and the sterile groups according to urine culture results. Subsequently, MCR, white blood cell (WBC) and bacteria in the urinary samples from patients were detected and compared between the two groups.Results Finally, 253 patients were enrolled including 157 urine culture positive patients and 96 urine culture negative patients (sterile group). After logarithmic transformation in 2 as the base, the MCR, WBC, and bacteria were separately presented as log2 MCR, log2 WBC(quantitative) , and log2 bacteria. The values of log2 MCR(8.6±2.5 vs. 5.4±1.5, t=-12.453, P=0.001), log2 WBC(quantitative) (8.0±2.5 vs. 5.2±1.8, t=-10.332, P=0.001), log2 bacteria (11.4±2.5 vs. 8.2±2.8, t=-9.297, P=0.001) and WBC (semi-quantitative) [2 (interquartile range 1, 3) vs. 1 (interquartile range 0.5, 1), Z=-7.580, P=0.001] showed significant difference between the urine culture positive group and the sterile group. Among the urine culture positive group, the values of log2 MCR of the gram positive and gram negative subgroups were 7.2±2.5 and 9.0±2.4 (t=4.016, P=0.001), respectively. The correlation between log2 MCR and log2 WBC (quantitative), log2 bacteria, WBC (semi-quantitative) was 0.708 (Pearson correlation, P=0.001), 0.381 (Pearson correlation, P=0.001), and 0.606 (Spearman correlation, P=0.001), respectively. Conclusions MCR is positively correlated with WBC counts and could be served as a promising biomarker for diagnosis of UTI. MCR could be even used for initial inference of infectious bacteria types of UTI.

Nutrient intake and environmental enteric dysfunction among Nepalese children 9-24 months old-the MAL-ED birth cohort study.

BACKGROUND: Nutrient deficiencies limit the growth and turnover of intestinal mucosa, but studies assessing whether specific nutrients protect against or improve environmental enteric dysfunction (EED) are scarce. We aimed to investigate associations between nutrient intake and EED assessed by lactulose:mannitol (L:M) ratio, anti-1-antitrypsin, myeloperoxidase (MPO), and neopterin (NEO) among children 9-24 months in Bhaktapur, Nepal. METHODS: Among 231 included children, nutrient intake was assessed monthly by 24 h recalls, and 3-month usual intake was estimated using Multiple Source Method. Associations between nutrient intake and L:M ratio (measured at 15 months) were assessed using multiple linear regression, while associations between nutrient intake and fecal markers (measured quarterly) were assessed using Generalized Estimating Equations (GEE) models. RESULTS: We found that associations between nutrient intake from complementary food and L:M ratio, alpha-1-antitrypsin (AAT), MPO and NEO were generally negative but weak. The only significant associations between nutrient intake (potassium, magnesium, phosphorous, folate, and vitamin C) and markers for intestinal inflammation were found for MPO. CONCLUSION: Negative but weak associations between nutrient intake and markers of intestinal inflammation were found. Significant associations between several nutrients and MPO might merit further investigation.

Urinary myeloperoxidase to creatinine ratio as a new marker for monitoring treatment effects of urinary tract infection.

OBJECTIVE: We want to determine whether urinary myeloperoxidase to creatinine ratio could be served as a new marker for monitoring treatment effects of urinary tract infection or not. METHODS: A total of 328 patients suspected of UTI were enrolled in present study. Patients been received antibiotic therapy within two weeks were excluded (n = 26). Patients with urine contaminated specimens (n = 49) and negative urine culture results (n = 96) were also excluded, the remaining culture positive subjects (n = 157) were followed up for 7 to 14 days, finally, a total of 49 subjects were followed up and further divided into cure (n = 35) and none-cure (n = 14) subgroups according to urine culture results. MPO concentration was determined by immunoturbidimetric method and creatinine level was measured by creatinine enzyme method. Two sided P values < 0.05 were considered statistically significant. RESULTS: Urinary MCR level between before and after antibiotic treatment of cure group were (1437.1 ±â€¯1777.9 vs.48.3 ±â€¯59.3, t = 4.608, P = 0.001), respectively. Urinary MCR level between before and after antibiotic treatment of none-cure group were (1633.1 ±â€¯2168.7 vs. 999.4 ±â€¯1708.0, t = 1.809, P = 0.094), respectively. CONCLUSIONS: Urinary MCR could be served as a promising marker for monitoring treatment effects of urinary tract infection.

New markers: urine xanthine oxidase and myeloperoxidase in the early detection of urinary tract infection.

OBJECTIVES: The aim of this study was to evaluate if xanthine oxidase and myeloperoxidase levels quantitation method may alternate routine culture method, which takes more time in the diagnosis of urinary tract infections. MATERIAL AND METHODS: Five hundred and forty-nine outpatients who had admitted to Clinic Microbiology Laboratory were included in the study. The microorganisms were identified by using VITEK System. The urine specimens that were negative from the quantitative urine culture were used as controls. The activities of MPO and XO in spot urine were measured by spectrophotometric method. RESULTS: Through the urine cultures, 167 bacteria were isolated from 163 urine specimens; 386 cultures yielded no bacterial growth. E. coli was the most frequent pathogen. In infection with E. coli both XO and MPO levels were increased the most. The sensitivity, specificity, positive predictive value, and negative predictive value for XO were 100%, 100%, 100%, and 100%, respectively. These values for MPO were 87%, 100%, 100%, and 94%, respectively. CONCLUSION: These data obtained suggest that urine XO and MPO levels may be new markers in the early detection of UTI.

IL-17, neutrophil activation and muscle damage following endurance exercise.

The T-cell subset Th17 is induced partly by interleukin (IL)-6 and activated by IL-23, and produces a proinflammatory cytokine IL-17. Since IL-6 increases dramatically following long-lasting endurance exercise, this response may also stimulate the induction of IL-17 and IL-23 after exercise. The aim of this study was to clarify the dynamics of IL-17 in association with endurance exercise-induced muscle damage and inflammatory responses. Fourteen male triathletes participated in a duathlon race consisting of 5 km of running, 40 km of cycling and 5 km of running. Venous blood and urine samples were collected before, immediately after 1.5 h and 3 h after the race. Plasma and urine were analyzed using enzyme-linked immunosorbent assays (ELISA). Haematological and biochemical variables such as neutrophil activation marker (myeloperoxidase: MPO), muscle damage marker (myoglobin: Mb) and soluble receptor activator of nuclear factor (NF)-KB ligand (sRANKL) were also determined to estimate the biological and pathological significance. Plasma concentrations oflL-6 (+26.0x), MPO (+3.2x) and Mb (+4.9x) increased significantly immediately after the race and IL-17 and IL-23 tended to increase. Furthermore, plasma concentrations of IL-12p40 and sRANKL increased significantly after the race. The measured parameters related to Thl 7 cytokines in the urinary output were closely correlated with each other and muscle damage marker. These findings suggest that IL-17 induced by IL-6 and activated by IL-23 or other IL-17 producing-cells and IL-23 might promote neutrophil activation and muscle damage following prolonged endurance exercise.

Assessment of uric acid and lipid peroxidation in serum and urine after hypoxia-ischemia neonatal in rats.

The aim of this study was to evaluate urinary uric acid (UA) and lipid peroxidation levels, plasma myeloperoxidase (MPO) and adenosine deaminase (ADA) activities, and serum UA in neonatal rats subjected to hypoxia-ischemia neonatal HI model. The relevance of the findings is the fact that urinary lipid peroxidation and UA levels were significantly higher in 8 days in HI group when compared with the control, returning to baseline levels 60 days after HI. Hence, being an indication of purinic degradation during these first days post-HI. Furthermore, the higher levels of malondialdehyde (MDA) in urine in this period may be related to inadequate scavenging abilities of the immature nervous system and being noninvasive it may suggest the use of urinary MDA measurement as a marker for lipid peroxidation after HI insult. In application terms, these findings can help develop therapeutic interventions as soon as 8 days after HI.

Gender-specific differences in the urinary expression of aldosterone, IL-1α and IL-1ß.

AIMS: This pilot investigation examined the possibility of using urine specimens to explore the difference between the expression of several biomarkers based on gender. These biomarkers include several associated with cardiac damage, oxidative stress and inflammation. MATERIALS & METHODS: Urine specimens were assayed for total protein, aldosterone, high-sensitivity C-reactive protein, myeloperoxidase and IL-1α and -1ß using ELISA. RESULTS: We observed significant differences between the sexes for aldosterone and IL-1α and -1ß. CONCLUSION: The presence of gender-based differences in the urinary expression of these biomarkers may be important for establishing normal baseline values in males and females, and may prove to be of value in the development of rapid noninvasive ways to assess inflammatory and oxidative injury during routine urinalysis.

Seasonal differences of peak expiratory flow rate variability and mediators of allergic inflammation in non-atopic adolescents.

Variations in peak expiratory flow (PEF) and serum eosinophil mediators were studied in healthy adolescents. Twenty-five boys and 31 girls, 11-16 years of age (mean age 14.3 years), were selected and investigated during the birch pollen season of 1995; 45 were also investigated during the autumn of the same year. The PEF was measured twice daily and eosinophil mediators in serum and in urine were measured by radioimmunoassay (RIA) once during the birch pollen season and once in autumn. The type values of the daily PEF variation, expressed in amplitude percentage mean, were 6.4 and 3.9%, mean values were 7.35 and 6.74%, and the 95th percentiles were 18 and 14%, during the birch pollen season and autumn, respectively. The 95th percentiles were 41 and 38 microg/l for serum eosinophil cationic protein (s-ECP), 74 and 62 microg/l for serum eosinophil protein X (s-EPX), 987 and 569 microg/l for serum myeloperoxidase (s-MPO), and 165 and 104 microg/mmol for urinary eosinophil protein X/urinary creatinine (u-EPX/u-creatinine), during the birch pollen season and autumn, respectively. The levels of the eosinophil mediators decreased significantly from May (n = 56) to November (n = 45), for s-ECP from a median value of 14 microg/l to 7 microg/l (p= 0.001), for s-EPX from a median value of 28 microg/l to 20 microg/l (p= 0.001), and for the neutrophil mediator, s-MPO, from a median value of 440 g/l to 292 g/l (p< 0.001). The PEF variability decreased significantly (p= 0.037), from spring (n = 55; median 8%, 95% confidence interval [CI] 7.8-10.19) to autumn (n = 44; median 6%, 95% CI 6.1-8.9). A significant correlation was found between the levels of s-ECP and s-EPX (rs = 0.7, p< 0.001), between s-ECP and s-MPO (rs = 0.6, p< 0.001), between s-EPX and s-MPO (rs = 0.4, p< 0.005), and between s-EPX and u-EPX/u-creatinine (rs = 0.6, p< 0.0001), in the birch pollen season (n = 56) and in the autumn (n = 45). There was a positive correlation found in PEF variability between the two seasons (n = 43; rs = 0.5, p= 0.0006). No other correlation was found between PEF variability and any other parameters. The difference in the levels of eosinophil mediators between seasons in non-atopic, healthy children is unexplained. Normal limits for mediators were higher and PEF variability was almost the same as has been reported in adults. When using normal values, seasonal influences should be considered.

Renal graft rejection or urinary tract infection? The value of myeloperoxidase, C-reactive protein, and alpha2-macroglobulin in the urine.

Previous investigations have shown that the determination of two acute-phase proteins in the urine, C-reactive protein (CRPu) and alpha2-macroglobulin (alpha2-MGu), allows a noninvasive diagnosis of acute renal graft dysfunction. A reliable differentiation between rejection and urinary tract infection can be made only when considering the C-reactive protein in serum and urine at the same time (CRPs:CRPu ratio). Therefore, a diagnostic procedure independent of parameters other than urinary proteins is needed. As granulocytes play only a minor role in graft rejection but are a common feature in urinary tract infection, we determined a marker of granulocytes (myeloperoxidase) in urine (MPOu). Eighty-nine renal transplant recipients were included in the study. In normal courses, CRPu, alpha2-MGu, and MPOu were within the normal range. In 15 cases of acute interstitial rejection, an increased excretion of CRPu and alpha2-MGu could be confirmed, but MPOu could not be detected. On the occasion of acute vascular rejection (n=6), with the exception of one case, MPOu could not be observed. The pattern of the three urinary proteins differed in urinary tract infections (n=40): MPOu could be detected in all cases, CRPu in 50% of cases, and alpha2-MGu in 73% of cases. In patients with cytomegalovirus infection (n=7), no MPOu, CRPu, or alpha2-MGu was found. In conclusion, the simultaneous measurement of the three proteins allows a complete, noninvasive, differential diagnostic procedure of renal graft dysfunction.

Neutrophil enzymes in urine for the detection of urethral infection in men.

OBJECTIVES: To determine if assaying the neutrophil enzymes, neutrophil elastase (NE) and myeloperoxidase (MPO) in the urine of men attending a genitourinary medicine clinic could identify those with Neisseria gonorrhoeae or Chlamydia trachomatis infections, and those with urethritis (with or without an identified infection with either organism), and to compare the new assays with the performance of the leucocyte esterase test (LET). METHOD: 100 men had urethral specimens taken for Gram-stained urethral smear, culture for N gonorrhoeae, and for C trachomatis testing by enzyme immunoassay. First-voided urines were tested for leucocyte esterase by commercial dipstick (positives were defined as greater than "trace") and then frozen at -20 degrees C prior to being assayed for NE and MPO. RESULTS: Five patients had gonorrhoea, six had chlamydia and none had both. Evidence of urethritis (> 5 polymorphonuclear leucocytes in four x 1000 fields) was found in 29 men. The results of the urine assays showed MPO levels to be non-discriminatory; however NE levels were significantly elevated in patients with proven infection or urethritis or both. Using NE values from men with no infection or urethritis an upper limit for normal was defined. Utilising this, the sensitivity of the elastase assay was calculated and found to be superior to the sensitivity of LET for detecting proven infection (64% vs 36%) and urethritis (52% vs 31%). CONCLUSIONS: Further studies of neutrophil elastase in the pathogenesis, diagnosis and treatment of urethritis are indicated.