Impressive renal damage after acute pyelonephritis in a child

Validation of quantitative loop-mediated isothermal amplification assay using a fluorescent distance-based paper device for detection of Escherichia coli in urine

Uropathogenic Escherichia coli (UPEC) causes up to 90% of urinary tract infections (UTI) which is more prevalent among females than males. In urine, patients with symptomatic UTI usually have a high concentration of bacterial infection, ≥ 105 colony-forming units (CFU) per mL, in which the culture method is regularly the gold standard diagnosis. In this study, a simple and inexpensive distance-based paper device (dPAD) combined with the fluorescent closed tube LAMP assay was validated for simultaneously screening and semi-quantifying the infection level of E. coli in 440 urine samples of patients with UTI. The dPAD could measure the LAMP amplicons and semi-quantify the levels of E. coli infection in heavy (≥ 104 CFU/mL), light (≤ 103 CFU/mL) and no infection. The sensitivity and specificity had reliable performances, achieving as high as 100 and 92.7%, respectively. The one step LAMP assay could be performed within 3 h, which was 7.5 times faster than the culture method. To empower early UTI diagnosis and fast treatment, this inexpensive dPAD tool combined with the fluorescent closed tube LAMP assay is simple, reliably fast and practically portable for point-of-care settings, particularly in resource-limited areas, which can be set up in all levels of healthcare facilities.

Development of a fluorescent distance-based paper device using loop-mediated isothermal amplification to detect Escherichia coli in urine

The highly sensitive and selective determination of Escherichia coli (E. coli) in urine was achieved using a SYBR™ safe loop-mediated isothermal amplification (LAMP) method with a distance-based paper device. New primers set specific to multi-copy the 16s rRNA gene of E. coli were designed and used in this study. The detection sensitivity of these primers was higher than in related work and they could be incorporated with a low-cost paper-based device to quantify E. coli in urine at a concentration lower than 101 CFU mL-1. Regarding standard artificial urine, a linear range of a 10-fold dilution of E. coli concentration (105-100 CFU mL-1) with an R-square value (R2) = 0.9823 was observed directly using a fluorescent migratory distance of the 4 μL reaction mixture in the detection zone under blue light without the need for postreaction staining process. Based on the device, E. coli infection could be significantly categorized into 3 groups; none, light, and heavy levels, which is beneficial for UTI diagnosis. Hence, this paper-based device is suitable for use with the SYBR™ Safe-LAMP assay to semi-quantify E. coli, especially in resource-limited settings due to advantages of low cost, simple fabrication and operation, and no requirement for sophisticated instruments, as well as its disposability and portability.

Effect of Thymoquinone on Oxidative Stress in Escherichia coli-Induced Pyelonephritis in Rats

BACKGROUND

Recurrent urinary tract infections are important in children and adults with diabetes mellitus and/or incontinence due to risk of pyelonephritis (PYN) and renal damage. There is a positive correlation released free radicals during PYN and renal damage. Experimental studies showed that antioxidant agents improve renal damage when used immediately after bacterial inoculation.

OBJECTIVE

The aim of the present study was to evaluate whether treatment by thymoquinone (TQ) before or during Escherichia coli inoculation prevents oxidative damage in acute pyelonephritis (PYN) in an ascending obstructive rat model.

METHODS

In this study, 42 Wistar rats were grouped as follows: control, PYN (24, 48, and 72 hours), and TQ-PYN (24, 48, and 72 hours). E. coli (1 ×10(9) colony forming units) was inoculated into the bladder via urethral catheterization in both the PYN and TQ groups. TQ injections were performed 24 hours before bacteria inoculation and repeated at 24-hour intervals during the indicated time at a dose of 10 mg/kg body weight intraperitoneally in TQ groups.

RESULTS

Superoxide dismutase activity was statistically lower in the TQ-PYN-48 and -72 groups than the PYN-48 and -72 groups (P < 0.001, P = 0.004, respectively). Catalase activity was significantly higher in PYN-24, -48, and -72 groups than the control group (P < 0.001). In addition, there was a significant difference between the TQ-PYN-24, -48, and -72 groups and PYN groups in terms of glutathione peroxidase activity (P < 0.001, P = 0.026, P = 0.046, respectively). When the TQ-PYN-72 group was compared with the PYN-72 group, malondialdehyde levels were significantly lower in the TQ-PYN-72 group than in the PYN-72 group (P = 0.033). A histologic examination also confirmed the protective effect of TQ. In statistical analysis of histopathologic findings, there were significant differences between the PYN-24 and TQ-PYN-24, PYN-48 and TQ-PYN-48, and PYN-72 and TQ-PYN-72 groups (P = 0.008, P < 0.001, P < 0.001, respectively).

CONCLUSIONS

The results indicate that TQ administration attenuated the oxidative damage that occurred in PYN and, therefore, could be used as a supportive agent to protect the kidneys from oxidative damage caused by PYN.

Genotypic and phenotypic characterization of Escherichia coli isolates from children with urinary tract infection and from healthy carriers

BACKGROUND

Urinary tract infections (UTI) are common in children and contribute significantly to morbidity and mortality. The major cause is Escherichia coli, carrying multiple virulence-associated factors (VFs). However, the specific traits that distinguish childhood uropathogenic E. coli from fecal commensals of healthy children are incompletely defined.

METHODS

We used a multiplex polymerase chain reaction-based reverse line blot assay, several additional polymerase chain reactions and phenotypic methods to compare distributions of virulence traits (22 VF genes, UTI-associated O types, phylogenetic groups, sequence type 131 and expression of selected VFs), between 212 E. coli isolates from children ≤ 5 years with UTI (109 cystitis and 103 pyelonephritis) and 115 fecal isolates from healthy children of similar age, collected during the same time period.

RESULTS

The studied traits were most prevalent among pyelonephritis, followed closely by cystitis isolates and were uncommon among fecal isolates. Eight VF genes differentiated pyelonephritis from cystitis isolates, but aggregate VF scores in these 2 UTI groups were similar. Most of the studied phenotypic characteristics showed a similar descending prevalence gradient from pyelonephritis, through cystitis, to fecal isolates. Coexpression of biofilm components, curli and cellulose, was strongly associated with pyelonephritis, phylogenetic group B2, individual VF genes and higher VF scores. Two-thirds (67%) of clinical isolates belonged to phylogenetic group B2 and, of these, 12% belonged to the sequence type 131 clonal group, compared with 14% and 1%, respectively, of fecal isolates.

CONCLUSIONS

These findings identify specific virulence factors, O types and a virulent clonal group (sequence type 131), as potential targets for UTI prevention strategies in children.

[Comparative study of C-reactive protein and procalcitonin in the severity diagnosis of pyelonephritis in children]

OBJECTIVE

The aim of this study is to compare two biologic parameters; C-reactive protein (CRP) and procalcitonin (PCT) in the detection of acute renal lesions assessed by DMSA scintigraphy in the urinary tract infection in child.

DESIGN

In a prospective study, serum PCT, CRP and leukocyte counts were measured for children admitted, between January and December 2010, with a first episode of febrile urinary tract infection.

RESULTS

Seventy-five children were enrolled in the study. Thirty-three patients had renal lesions (group A) and 42 had a normal DMSA scintigraphy (group B). The mean PCT level was significantly higher in group A than in group B (8.81 ng/mL versus 1.7 ng/mL, P=0.01). In this study, using receiver operating characteristic (ROC) curve, we identified that the optimal cut-off value with ideal sensitivity and specificity for PCT in detection of renal lesions was 0.76 ng/mL and for CRP, it was 70 mg/L. The sensitivity, the negative predictive value and the indice of Youden of the cut-off value of PCT were significantly higher than CRP (82% versus 70%; 84% versus 70% and 0.58 versus 0.25).

CONCLUSIONS

This study confirmed that the serum PCT level was more sensitive and specific than the CRP in the detection of renal lesions in the first urinary tract infection in child.

The effect of vitamin E or vitamin A on the prevention of renal scarring in children with acute pyelonephritis

BACKGROUND

Numerous factors may contribute to renal tissue injury after urinary tract infection. We have evaluated the effects of vitamins A or E supplementation in combination with antibiotics for the prevention of renal scarring in acute pyelonephritis.

METHODS

A simple non-blind randomized clinical trial was conducted on 61 children aged 1 month to 10 years between 2004 and 2006. The inclusion criteria were positive urine culture, clinical findings, and 99mTc-dimercaptosuccinic acid (DMSA) scintigraphy-based evidence in favor of acute pyelonephritis. The children were randomized into three treatment groups: 10-day treatment with only antibiotics (control group; n = 25) and 10-day treatment with supplements of vitamin A (n = 17) or vitamin E (n = 18) in addition to antibiotics during the acute phase of infection. The final analysis was performed after excluding male patients. Each patient was evaluated twice by 99mTc-DMSA scintigraphy performed at least 6 months apart. P < 0.05 was considered to be statistically significant.

RESULTS

The analysis included 108 kidney units. The frequency of inflammation at the beginning of therapy was not significantly different in the three groups (63.3 % in vitamin A, 61 % in vitamin E, and 76.2 % in the control group). A worsening of lesions, based on the second 99mTc-DMSA scan, was observed in 42.5, 0, and 23.3 % of the control, vitamin E, and vitamin A patients, respectively (LR = 26.3, P < 0.001).

CONCLUSION

Vitamins A or E supplements were effective in reducing renal scarring secondary to acute pyelonephritis.

Paired organs-should they be treated jointly or separately in internal dosimetry?

PURPOSE

Size, shape, and the position of paired organs are different in abdomen. However, the counterpart organs are conventionally treated jointly together in internal dosimetry. This study was performed to quantify the difference of specific absorbed fraction of organs in considering paired organs jointly like single organs or as two separate organs.

METHODS

Zubal phantom and GATE Monte Carlo package were used to calculate the SAF for the self-absorption and cross-irradiation of the lungs, kidneys, adrenal glands (paired organs), liver, spleen, stomach, and pancreas (single organs). The activity was assumed uniformly distributed in the organs, and simulation was performed for monoenergetic photons of 10, 50, 100, 500, 1000 keV and mono-energetic electrons of 350, 500, 690, 935, 1200 keV.

RESULTS

The results demonstrated that self-absorption of left and right counterpart organs may be different depending upon the differences in their masses. The cross-irradiations between left-to-right and right-to-left counterpart organs are always equal irrespective of difference in their masses. Cross-irradiation from the left and right counterpart organs to other organs are different (4-24 times in Zubal phantom) depending on the photon energy and organs. The irradiation from a single source organ to the left and right counterpart paired organs is always different irrespective of activity concentration.

CONCLUSIONS

Left and right counterpart organs always receive different absorbed doses from target organs and deliver different absorbed doses to target organs. Therefore, in application of radiopharmaceuticals in which the dose to the organs plays a role, counterpart organs should be treated separately as two separate organs.© 2011 American Association of Physicists in Medicine.

Reliability of renal length measurements made with ultrasound compared with measurements from helical CT multiplanar reformat images

OBJECTIVE

The purpose of this article is to determine the reliability of sonographic renal length measurements compared with measurements obtained from helical CT multiplanar reformat images and compared with standard renal growth curves.

MATERIALS AND METHODS

A retrospective review was performed of 76 subjects who underwent both renal ultrasound and abdominal CT within 2 weeks of one another. Renal lengths were measured using oblique coronal reformat images of helically acquired CT data by two observers on two occasions. Intraobserver and interobserver error for these measurements were calculated. Ultrasound renal length measurements were compared with CT measurements. Measurement variation was compared with standard renal growth curves.

RESULTS

The mean (± SD) of the absolute value of interobserver error of CT measurements was 0.9 ± 0.8 mm. Compared with CT, individual ultrasound measurements underestimated renal length by 1.5 ± 5.6 mm on average, with a 95% CI of -12.5 to 9.5 mm. When the maximum of three ultrasound renal length measurements was used, the SD was 4.7 mm, with a 95% CI of -8.2 to 10.1 mm of the reported renal length. This corresponds to greater or less than 3.3 years of normal renal growth.

CONCLUSION

Lack of renal growth can be asserted only when renal length falls below the growth curve, taking into account the corresponding measurement error limits, which we found to be greater or less than 9.3 mm. If the follow-up measurement falls within these limits, one should not infer lack of appropriate renal growth, even if the renal length measurement decreases or remains unchanged for up to 3 years.

Characterisation of uropathogenic Escherichia coli from children with urinary tract infection in different countries

Uropathogenic Escherichia coli (UPEC) carry many virulence factors, including those involved in long-term survival in the urinary tract. However, their prevalence and role among UPEC causing urinary tract infection (UTI) in children is not well studied. To further understand the virulence characteristics of these bacteria, we investigated the prevalence of antibiotic resistance, antigen 43 genes, curli and cellulose among UPEC in children from different countries. Isolates (n = 337) from five countries were tested for antibiotic susceptibility, phylogenetic groups, prevalence of flu, fluA(CFT073), fluB(CFT073), curli and cellulose. High prevalence of multidrug resistance and extended spectrum beta lactamase production was found among Iranian and Vietnamese isolates. Resistance was associated with phylogenetic group D while group B2 was associated with fluA(CFT073) and fluB(CFT073). Fewer Iranian isolates carried fluA(CFT073), curli and cellulose. fluB(CFT073) was most prevalent among Slovak isolates. Ampicillin and amoxicillin/clavulanic acid resistance was prevalent among fluA(CFT073)- and fluB(CFT073)-positive Australian, Iranian and Swedish isolates. Lack of curli and cellulose was associated with resistance among Vietnamese isolates. We conclude that major differences exist in the prevalence of antibiotic resistance among UPEC from different countries. Associations observed between resistance and virulence factors may, in different ways, promote the long-term survival of UPEC in the urinary tract.