Successive Urine Samples Research Articles

Within-Host Microevolution of Pseudomonas aeruginosa Urinary Isolates: A Seven-Patient Longitudinal Genomic and Phenotypic Study.

BackgroundPseudomonas aeruginosa is responsible for up to 10% of healthcare associated urinary tract infections (UTI), which can be difficult to treat and can lead to bacterial persistence. While numerous whole genome sequencing (WGS) analyses have explored within-host genomic adaptation and microevolution of P. aeruginosa during cystic fibrosis (CF) infections, little is known about P. aeruginosa adaptation to the urinary tract.ResultsWhole genome sequencing was performed on 108 P. aeruginosa urinary isolates, representing up to five isolates collected from 2 to 5 successive urine samples from seven patients hospitalized in a French hospital over 48–488 days. Clone type single nucleotide polymorphisms (ctSNPs) analysis revealed that each patient was colonized by a single clone type (<6000 SNPs between two isolates) at a given time and over time. However, 0–126 SNPs/genome/year were detected over time. Furthermore, large genomic deletions (1–5% of the genome) were identified in late isolates from three patients. For 2 of them, a convergent deletion of 70 genes was observed. Genomic adaptation (SNPs and deletion) occurred preferentially in genes encoding transcriptional regulators, two-component systems, and carbon compound catabolism. This genomic adaptation was significantly associated with a reduced fitness, particularly in artificial urine medium, but no strict correlation was identified between genomic adaptation and biofilm formation.ConclusionThis study provides the first insight into P. aeruginosa within-host evolution in the urinary tract. It was driven by mutational mechanisms and genomic deletions and could lead to phenotypic changes in terms of fitness and biofilm production. Further metabolomic and phenotypic analyses are needed to describe in-depth genotype-phenotype associations in this complex and dynamic host-environment.

Evaluation of urinary metabolites of 1-nitropyrene as biomarkers for exposure to diesel exhaust in taxi drivers of Shenyang, China

Diesel exhaust (DE) is a significant contributor to the toxicity associated with particulate matter (PM). 1-Nitropyrene (1-NP) has been used as a molecular marker for DE, and the urinary metabolites of 1-NP have been proposed as biomarkers for exposure to DE. In this study, several urinary 1-NP metabolites were evaluated for their utility as markers of short-term exposures to DE. The study population was a cohort of 24 taxi drivers from Shenyang, China, who submitted urine samples collected before, after, and the next morning following their workshifts. The urinary metabolites studied were isomers of hydroxy-1-nitropyrene (3-, 6-, 8- OHNPs) and hydroxy-N-acetyl-1-aminopyrene (3-,6-, 8-OHNAAPs). Exposure to DE was estimated based on exposure to 1-NP in air samples collected during and after the driver's workshift; 6- and 8-OHNP, and 8-OHNAAP were consistently detected in the drivers' urine. Concentrations of the metabolites in the taxi drivers' urine were greater than metabolite levels previously reported in non-occupationally exposed subjects; however no associations were observed between subject-specific exposures to 1-NP and urinary metabolites measured at the end of the workshift or in the next morning void. Significant autocorrelation was observed in metabolite levels in successive urine samples, from which half-lives for urinary elimination of ~10-12 h were estimated. These observations suggest that, in an occupational setting, urinary 1-NP metabolites may be more suitable as markers of ongoing exposure (timescales of several days) rather than indicators of acute exposure associated with single workshifts.

A case of consistent discrepancies between urine and blood human chorionic gonadotropin measurements

Our laboratory was confronted with two successive urine samples from a single patient which tested positive for human chorionic gonadotropin (hCG) when tested with both qualitative and quantitative assays, combined with no detectable hCG in corresponding plasma samples. Serial dilution and recovery experiments were performed in order to investigate the presence of interfering substances or a high-dose hook effect. The ovarian cysts that were removed from this patient were immunohistochemically stained using polyclonal anti-human hCG antibodies. Furthermore, a urine sample was sent to the USA hCG Reference Service for hCG variant analysis. Dilution and recovery experiments in urine and plasma samples were unremarkable. The biopsy stained negative for human hCG and free β-subunit. hCG isoform analysis in the urine sample revealed that approximately 87.5% of the immunoreactive hCG lacked the β-subunit C-terminal peptide (CTP). We report a rare case in which two successive urine samples test positive for hCG whereas in corresponding plasma samples hCG is undetectable. The majority of the total hCG contained a degraded form of β-subunit that lacks the CTP. This hCG variant, possibly of pituitary origin, is thought to have an extreme fast clearance rate possibly explaining the discordance between the hCG results in urine and plasma samples.

Pregnancy Diagnosis in Macaco fascicularis

The Subhuman Primate Pregnancy Tube Test (SHPT test) was useful for early pregnancy diagnosis in cynomolgus monkeys (Macaca fascicularis). Test results were correct in 86.5% of series of four successive urine samples. SHPT test results were not confirmed in 13.5% of series, comprising two (false) negative series in pregnant animals and 13 (false) positive series in nonpregnant animals. In ten of 13 false-positive series, a positive-negative sequence was observed in successive test results, presumably due to a decline in chorionic gonadotropin levels. In all animals with a false-positive SHPT test, early embryonic mortality was most probable, since all showed normal cycling activity immediately afterwards. Postmating bleeding records were not reliable for pregnancy diagnosis. A practical approach for the use of the SHPT test in the individual breeding of monkeys is given.

Urinary and faecal excretion of marker calcium (46Ca) by low birthweight infants.

Low birthweight infants were given calcium enriched in 46Ca in a single feed. The specific activity of successive urine samples showed that the absorption of the marker was largely complete in about 4 hours. The rate of decrease of urinary specific activity after 3 1/2 hours was exponential and very similar in 8 sets of observations in 6 infants. Its extrapolation backwards to 1 hour may indicate the size of the exchangeable calcium pool, usually about 200 mg/kg body weight. Completeness of faecal collection for estimation of 46Ca is essential for accurate determination of true absorption and endogenous faecal excretion of natural Ca. In 5 infants examined, nor marker was detectable in faeces excreted later than 48 hours after the first stool containing marker. Nevertheless, reasons are given why a collection period limited to 48 hours may sometimes involve error.

Some theoretical considerations of the metabolism of [4-14-C]cortisol in man.

SUMMARY Specific activities were determined for cortisol and its metabolites isolated from several successive urine samples collected from patients who had each received a single injection of a tracer dose of [4-14C]cortisol. Some theoretical aspects of the curves relating specific activity to time after injection are considered. Evidence is presented and discussed for an alternative route to the 11-oxygenated 17-oxosteroid metabolites of cortisol probably involving not an initial reduction of the ring A of cortisol but a simultaneous cleavage of the side-chain at C-17 of the steroid nucleus and reduction of ring A.

Measurement of total exchangeable potassium

1. (1) Exchangeable body potassium (K e) was estimated, in 193 instances in 140 patients. 2. (2) Fifty patients were in heart failure, 36 had steatorrhoea, the rest included medical patients shortly before their discharge from hospital and others ill with a variety of chronic maladies undergoing medical treatment; none were oedematous. 3. (3) In 77% of instances distribution of radioactive potassium throughout the potassium of the body was complete 20–24 h, and in 31% as early as 3–10 h after giving it. 4. (4) In 23% of instances distribution was clearly incomplete after 24 h. Delay was not related to the presence or absence of oedema, nor only noted in patients in heart failure. 5. (5) Variability in successive estimates of K e made after a lapse of 24 h commonly exceeded that expected from known errors of the method. 6. (6) In some individuals an association was noted between variation in successive estimates of K e and variation in concentration of chemically determined potassium in successive urine samples, analysis of which underlay the estimates of K e. 7. (7) It is concluded that: (a) a single estimate of K e is worthless; (b) several estimates from successive samples are required for meaningful information; (c) completeness of distribution and mixing of radioactive potassium with body potassium should be assessed in each individual.

A comparison of quantitative methods in the investigation of urinary infections

Bacterial colony counts and urinary white and non-squamous epithelial cell excretion rates have been compared in successive urine samples from 51 hospital patients. In all 19 cases with a colony count greater than 100,000/ml. the cell excretion rate was over 200,000/hour. Urinary cell concentrations correlate poorly with both colony counts and the cell excretion rate. It is concluded that simple culture of a properly taken urine sample combined with a measurement of the urinary cell excretion rate is adequate for the detection of most urinary infections. In the few instances where these methods do not provide a clear-cut result, colony counting techniques may be of value.