Prevalence of common carbapenemase genes and multidrug resistance among uropathogenic Escherichia coli phylogroup B2 isolates from outpatients in Wasit Province/ Iraq

Carbapenems are the last resort antimicrobials for the treatment of extended spectrum β-lactamases (ESBLs) producing Enterobacteriaceae. Emergence of carbapenems resistant group B2 uropathogenic E. coli (UPEC) is a major concern because of their high virulence. Prevalence of these enzymes and multidrug resistance (MDR) among B2 UPEC isolates from Iraqi outpatients with acute urinary tract infection (UTI) was evaluated in this research. Urine cultures were performed and the isolates were identified biochemically. Escherichia coli isolates were tested for phylogroup reference by quadraplex PCR, then B2 isolates were detected for antimicrobial resistance by disc diffusion test and carbapenemase genes by PCR. Escherichia coli was the most prevalent among Gram-negative isolates (66.6%) and B2 was the most detected phylogroup among E. coli isolates (33.9%). Most of B2 isolates showed high resistance rates to tested antimicrobials, especially β-lactams with MDR revealed in 100% of them. Whereas, low resistance rates were noted against carbapenems, aminoglycosides and nitrofurantoin. Carbapenemase genes were detected in 76.3% of B2 isolates. Of which, blaOXA-48 was the most frequent (57.8%), followed by blaPER (47.3%), blaKPC (15.7%), blaVEB and blaVIM (10.5%, for each). Whereas, blaGES and blaIMP genes were not found. Coproduction of these genes occurred among 17 isolates. The combination of blaOXA-48 and blaPER was the most frequent (41.1%). All carbapenemase producing isolates were MDR. These results revealed high prevalence of carbapenemase genes and MDR among B2 UPEC recovered in this study. In the study area. it is strongly advised to use aminoglycosides and nitrofurantoin for empirical treatment of UPEC.

Useful independent factors for distinguish infection and colonization in patients with urinary carbapenemase-producing Enterobacteriaceae isolation

OBJECTIVE

The aim of this study is to know epidemiologic and clinical differences among those patients colonized or infected by carbapenemase-producing Enterobacteriaceae (CPE) and develop a predictive model to facilitate the clinical approach concerning to start antimicrobial therapy.

METHODS

Observational retrospective cohort study was performed involving all patients with Urine carbapenemase-producing Enterobacteriaceae isolation (UCPEI) between November 2013 and July 2015. Patients were classifieds as colonized or infected considering Center for Disease Control and Prevention (CDC) definition for urinary tract infection (UTI).

RESULTS

A total of 72 patients were included, mean age 76.4 (IQR 23-99) years and 40 (55.6%) were women. Thirty-four (47.2%) were colonized and 38 (52.8%) met the criteria of UTI and were considered infected. The independent variables associated to infection were female sex, peripheral vascular disease, admission in medical ward, permanent urinary catheter carrier, previous antimicrobial therapy, and length of stay. Isolation of OXA-48 carbapenemase-producing Enterobacteriaceae behaved as a non UTI (colonization) factor in comparison with KPC or VIM CPE. The developed predictive model showed an area under the curve (AUC) of 0.901 (95% CI: 0.832-0.970; p < 0.001).

CONCLUSIONS

The predictive model that includes all this factors has demonstrated a good accuracy for infection diagnosis in these patients, an important issue considering that establishing the diagnosis of infection is not always easy in the profile of patients in which a CPE is isolated.

In vitro screening and evaluation of some Indian medicinal plants for their potential to inhibit Jack bean and bacterial ureases causing urinary infections

CONTEXT

Bacterial ureases play an important role in pathogenesis of urinary infections. Selection of plants was done on the basis of their uses by the local people for the treatment of various bacterial and urinary infections.

OBJECTIVE

Our investigation screens and evaluates 15 Indian medicinal plants for their possible urease inhibitory activity as well as their ability to inhibit bacteria causing urinary infections.

MATERIALS AND METHODS

Plant extracts in three different solvents (methanol, aqueous, and cow urine) were screened for their effect on Jack-bean urease using the phenol-hypochlorite method. Subsequently, seven bacterial strains were screened for their ability to release urease and further antimicrobial-linked urease inhibition activity and minimum inhibitory concentration of the tested extracts were evaluated by the agar well diffusion and microdilution method, respectively.

RESULTS

Five plants out of 15 crude extracts revealed good urease inhibitory activity (≥ 20% at 1 mg/ml conc.) and IC50 values for these extracts ranged from 2.77 to 0.70 mg/ml. Further testing of these extracts on urease-producing bacterial strains (Staphylococcus aureus NCDC 109, S. aureus MTCC 3160, Proteus vulgaris MTCC 426, Klebsiella pneumoniae MTCC 4030, and Pseudomonas aeruginosa MTCC 7453) showed good anti-urease potency with an MIC ranging from 500 to 7.3 µg/ml.

DISCUSSION AND CONCLUSION

The results of screening as well as susceptibility assay clearly revealed a strong urease inhibitory effect of Acacia nilotica L. (Fabaceae), Emblica officinalis Gaertn. (Phyllanthaceae), Psidium guajava L. (Myrtaceae), Rosa indica L. (Rosaceae), and Terminalia chebula Retz. (Combretaceae). Our findings may help to explain the beneficial effect of these plants against infections associated with the urease enzyme.

Multidrug resistance and extended-spectrum β-lactamases genes among Escherichia coli from patients with urinary tract infections in Northwestern Libya

INTRODUCTION

Multidrug resistance (MDR) and emergence of extended-spectrum β-lactamases (ESBLs) that mediate resistance to β-lactam drugs among Escherichia coli and other uropathogens have been reported worldwide. However, there is little information on the detection of ESBLs genes in E. coli from patients with urinary tract infections (UTIs) in the Arab countries using polymerase chain reaction (PCR), and in Libya such information is lacking.

METHODS

All patients attending Zawiya Teaching Hospital in Zawiya city between November 2012 and June 2013 suspected of having UTIs and from whom midstream urine samples were taken as part of the clinical workup were included in this prospective study. Samples were examined for uropathogens by standard bacteriological procedures. VITEK-2 automated microbiology system was used to identify the isolated uropathogens and determine the susceptibility of E. coli and Klebsiella spp. isolates to antimicrobials. In addition, phenotypically ESBLs-positive E. coli isolates were tested for ESBLs genes by PCR.

RESULTS

The present study enrolled 1,790 patients with UTIs. Uropathogens were found in 371 (20.7%) urine specimens examined. Mixed pathogens were detected in two specimens with 373 total pathogens isolated. E. coli and Klebsiella spp. were the predominant uropathogens at 55.8% (208/373) and 18.5% (69/373), respectively. Other pathogens were detected in 25.7% (96/373) of urine samples. Of the E. coli and Klebsiella spp. tested, 69.2 and 100% were resistant to ampicillin, 6.7 and 33.3% to ceftriaxone, and 23.1 and 17.4% to ciprofloxacin, respectively. MDR (resistance to ≥3 antimicrobial groups) was found in 69 (33.2%) of E. coli and in 29 (42%) of Klebsiella spp. isolates. ESBLs were detected phenotypically in 14 (6.7%) of E. coli and in 15 (21.7%) of Klebsiella spp. isolates. Thirteen out of the 14 phenotypically ESBL-positive E. coli were positive for ESBL genes by PCR. bla TEM gene was detected in seven isolates, bla OXA gene in 10 isolates and bla CTX-M gene in six isolates. bla SHV gene was not detected in the present study.

CONCLUSION

The isolation of MDR ESBL-producing uropathogens undoubtedly will limit the choices clinicians have to treat their patients with UTIs. Therefore, there is an urgent need for surveillance studies on antimicrobial resistance and prevalence of ESBLs among uropathogens to guide the clinical treatment of UTIs in Libya in the future.

Monolateral purple urine bag syndrome in a patient with bilateral nephrostomy tubes

Purple urine bag syndrome (PUBS) is a constellation of findings resulting in purple discoloration of the urine and/or urine drainage bag(s) occurring in patients with long-term urinary indwelling catheters. Other causative factors may include constipation, female gender, the presence of bacteria containing sulphatase and phosphatase enzymes, and alkaline urine. While the contributing factors for PUBS are linked with high morbidity, PUBS itself is a benign condition. A case study of monolateral PUBS in a patient with bilateral nephrostomy tubes (NTs) is presented.

Resistance trends and risk factors of extended spectrum β-lactamases in Escherichia coli infections in Aleppo, Syria

BACKGROUND

Recently, there has been a notable surge in urinary tract infections (UTIs) by extended spectrum β-lactamase (ESBL)-producing Escherichia coli, which considerably limits treatment options. This study aimed to determine prevalence, phenotypic patterns, and ESBL-production status of E coli in isolates from UTI patients along with uncovering locally relevant risk factors for contracting ESBL-producing E coli infections.

METHODS

One hundred four nonrepetitive urine samples were collected from 3 major hospitals in Aleppo, Syria. Antibiotic susceptibility and ESBL production were studied by disc diffusion and double disk synergy tests according to Clinical Laboratory Standards Institute guidelines. Epidemiologic analysis was done using χ(2) and multivariate logistic regression tests.

RESULTS

This study revealed high prevalence of multidrug-resistant (MDR) E coli reaching 63%, whereas ESBL-producing E coli exceeded 52%. The latter exhibited alarmingly elevated levels of coresistance to non-β-lactam antibiotics leading to vast increase in MDR rates in comparison with non-ESBL-producing E coli (83.6% vs 12.2%, respectively).

CONCLUSION

We found previous exposure to third-generation cephalosporins and fluoroquinolones to be a significant risk factor for ESBL-producing E coli infections, in addition to other known factors such as hospitalization and catheterization. Tigecycline and carbapenems demonstrated near perfect efficacy against tested E coli, so they rank high among treatment options.

Purple urine bag syndrome

Purple urine bag syndrome is a rare disorder where the plastic urinary catheter bag and tubing turn purple. The discolouration is due to the presence of indigo and indirubin pigments which are metabolites of tryptophan. It is associated with urinary tract infection. Bacteria that produce sulphatase and phosphatase are involved in the formation of these pigments. Purple urine bag syndrome is associated with higher morbidity and mortality, compared to urinary tract infection without this phenomenon. We present a case report of this rare phenomenon occurring in a 68-year-old woman.

Diagnostic potential of urinary enzymes and beta 2-microglobulin in acute urinary tract infection

Urinary excretions of beta 2-microglobulin (beta 2M), N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase, beta-glucuronidase, acid and neutral alpha-glucosidase as indicators of proximal tubular dysfunction were measured in patients with acute upper and lower urinary tract infection (UTI) and fever of non-renal origin. The sensitivity of beta 2M was 67% and of NAG 49% as assessed in more than 100 episodes of acute pyelonephritis. Combined use of beta 2M and NAG increased the sensitivity to 75%. The degree of beta 2-microglobulinuria and enzymuria was comparable in patients with acute pyelonephritis and fever due to non-renal infections. The excretion of beta 2M and the various enzymes was too variable and unpredictable in individual cases to be useful as diagnostic indicator. In localizing an acute UTI, tests for proximal tubular dysfunction seem to be of no more clinical value than properly measured body temperature.

Upregulation of heme oxygenase-1 as a host mechanism for protection against nitric oxide-induced damage in human renal epithelial cells

OBJECTIVES

To examine whether urinary tract infection-associated stimuli could regulate heme oxygenase-1 (HO-1) expression and to asses the significance of HO-1 in protecting urinary tract epithelial cells against nitric oxide (NO)-induced damage.

METHODS

Heme oxygenase-1 expression was investigated in the human renal epithelial cell line A498 in response to the uropathogenic Escherichia coli (UPEC) strain IA2, the NO-donor DETA/NONOate (DETA/NO), and proinflammatory cytokines (interleukin-1beta, tumor necrosis factor-alpha, and interferon-gamma) using reverse transcriptase polymerase chain reaction and Western blot analysis. Cell viability was examined by the trypan blue exclusion test and light microscopy.

RESULTS

The HO-1 inducer hemin and DETA/NO increased HO-1 expression in A498 cells, and glutathione depletion further increased HO-1 expression in response to DETA/NO and hemin. Stimulation with a UPEC strain or cytokines did not upregulate HO-1 expression. The cytokines induced inducible NO synthase expression and caused an increase in nitrite production. Hemin significantly decreased cytokine-induced NO production (P <0.001). DETA/NO decreased the cell viability by approximately 75%, but hemin was able to attenuate DETA/NO-induced cell damage.

CONCLUSIONS

The expression of HO-1 increased in human renal epithelial cells in response to NO, and the expression was further enhanced in glutathione-depleted cells. The bacteria per se or proinflammatory cytokines were not able to upregulate HO-1. Heme oxygenase-1 protects the cells against NO by feedback inhibition of NO production and by decreasing cell damage.

Evaluation of the Nitrite and Leukocyte Esterase Activity Tests for the Diagnosis of Acute Symptomatic Urinary Tract Infection in Men

For 422 male patients with symptoms indicative of a urinary tract infection, nitrite and leukocyte esterase activity dipstick test results were compared with results of culture of urine samples. The positive predictive value of a positive nitrite test result was 96%. Addition of results of the leukocyte esterase test did not improve the diagnostic accuracy of the nitrite test.

beta-Glucuronidase activity in cerebrospinal fluid pleocytosis due to urinary tract infection

AIM

This study examines the beta-glucuronidase activity in the cerebrospinal fluid (CSF) of patients with urinary tract infection (UTI) and sterile CSF pleocytosis and the feasibility of using these measurements for diagnostic purposes.

METHODS

beta-Glucuronidase activity was measured in the CSF from 22 in each group neonates and infants with UTI and sterile CSF pleocytosis, bacterial meningitis, aseptic meningitis of apparently viral etiology and controls without CSF pleocytosis.

RESULTS

The median (range) beta-glucuronidase activity in UTI with sterile CSF pleocytosis was 44.1 (33.2-57.1), whereas in the controls without CSF pleocytosis it was 19.1 (7.0-22.7), in aseptic meningitis of apparently viral etiology it was 26.5 (21.0-30.0) and in bacterial meningitis it was 168 (70.0-1152). The difference between the enzyme activity in the CSF of the patients with UTI and those in the other groups of neonates and infants is significant (p < 0.0001), with no overlapping between UTI and the other groups of children studied. Both the sensitivity and specificity of the activity was 100%. Conversely, there was a broad overlapping of the classic CSF laboratory parameters among the groups of subjects studied.

CONCLUSION

beta-Glucuronidase activity in cell-free CSF discerns, with much greater accuracy than the classic CSF laboratory parameters, sterile CSF pleocytosis due to UTI from that of bacterial and viral meningitis and from control subjects without CSF pleocytosis.

[Antilysozyme activity of microorganisms causing acute and chronic pyelonephritis]

Etiological structure of urine microflora was studied in patients with acute and chronic pyelonephritis. Gram-negative microorganisms dominated. Antilysozyme activity of 175 bacterial strains was studied. Detectability and potency of persisting potential were assessed regarding infectious-inflammatory process course. High antilysozyme activity of bacteria was revealed. This indicates potential ability of the bacteria to persist in the patients.

Caspase-3-dependent apoptosis in Escherichia coli-infected urothelium: involvement of inducible nitric oxide synthase

OBJECTIVE

To investigate if nitric oxide (NO) derived from inducible NO synthase (iNOS) regulates apoptosis and/or cell shedding in uroepithelial cells in vivo and in vitro, as bladder epithelial cells undergo shedding during urinary tract infection, which is considered a part of the host's defence and is thought to take place via an apoptotic pathway.

MATERIALS AND METHODS

Bladders and kidneys of mice infected with Escherichia coli were used to study caspase-3 immunoreactivity at different times after infection. Wild-type (E. coli 1177) and type-1 recombinant (E. coli PKL4) bacteria were used. iNOS-deficient mice were used to study the association of caspase-3 with iNOS. Isolated human uroepithelial cells were used to examine the effect of the NO donor DETA/NO and the peroxynitrite generator SIN-1 on caspase-3 activity and cell shedding in vitro.

RESULTS

Many caspase-3 immunoreactive neutrophils were found soon after infection and some superficial bladder epithelial cells were also immunoreactive for caspase-3.

CONCLUSIONS

Caspase-3 immunoreactivity was also detected in neutrophils and bladder epithelial cells of infected iNOS-deficient mice. There was no co-expression between iNOS- and caspase-3 in bladder epithelial cells. DETA/NO and SIN-1 did not stimulate caspase-3 activity or cell shedding in isolated human uroepithelial cells. Caspase-3 and iNOS are not co-expressed in uroepithelial cells and apoptosis is evident in the absence of iNOS. Exogenous NO did not induce apoptosis or cell shedding in isolated human uroepithelial cells.

Polyamine-mediated resistance of uropathogenic Escherichia coli to nitrosative stress

During the course of a urinary tract infection, substantial levels of nitric oxide and reactive nitrogen intermediates are generated. We have found that many uropathogenic strains of Escherichia coli display far greater resistance to nitrosative stress than the K-12 reference strain MG1655. By selecting and screening for uropathogenic E. coli transposon mutants that are unable to grow in the presence of acidified nitrite, the cadC gene product was identified as a key facilitator of nitrosative stress resistance. Mutation of cadC, or its transcriptional targets cadA and cadB, results in loss of significant production of the polyamine cadaverine and increased sensitivity to acidified nitrite. Exogenous addition of cadaverine or other polyamines rescues growth of cad mutants under nitrosative stress. In wild-type cells, the concentration of cadaverine produced per cell is substantially increased by exposure to acidified nitrite. The mechanism behind polyamine-mediated rescue from nitrosative stress is unclear, but it is not attributable solely to chemical quenching of reactive nitrogen species or reduction in mutation frequency.

Emergence of metallo-beta-lactamase producing Pseudomonas aeruginosa in Pakistan

We report a case of urinary tract infection due to metallo-beta-lactamase producing Pseudomonas aeruginosa resistant to carbapenems. This report signals an ominous development. Unless curbed by judicious use of antibiotics and early detection by screening tests, spread of this plasmid-mediated resistance can render the carbapenems ineffective.

Meprin metalloprotease expression and regulation in kidney, intestine, urinary tract infections and cancer

Meprins are unique plasma membrane and secreted metalloproteinases that are highly regulated at the transcriptional and post-translational levels. Meprin alpha and beta subunits are abundantly expressed in kidney and intestinal epithelial cells, are secreted into the urinary tract and intestinal lumen, and are found in leukocytes and cancer cells under certain conditions. Their location and proteolytic activities indicate functions at the interface of the host and the external environment, and in trafficking of macrophages and metastases of cancer cells. These proteases can be detrimental when there is tissue damage or disruption, as in acute renal injury or intestinal inflammation, and there is evidence they are involved in movement of leukocytes and cancer cells to sites of infection or in metastasis, respectively.

THE INFLUENCE OF UROPATHOGENIC ESCHERICHIA COLI AND PROINFLAMMATORY CYTOKINES ON THE INDUCIBLE NITRIC OXIDE SYNTHASE RESPONSE IN HUMAN KIDNEY EPITHELIAL CELLS

PURPOSE

Nitric oxide (NO) is an antibacterial factor that is produced by the enzyme inducible NO synthase (iNOS). Uroepithelial cells express iNOS in experimental models of urinary tract infection but the stimulatory and regulatory mechanisms are still unclear. We investigated the influence of uropathogenic Escherichia coli strains with different fimbrial expression and the effect of proinflammatory cytokines on the host iNOS response.

MATERIALS AND METHODS

A498 human kidney epithelial cells were stimulated with different uropathogenic E. coli strains, namely the P and type 1-fimbriated clinical isolate AD110, the recombinant P-fimbriated strain E. coli HB101(pPIL110-75) and the recombinant type 1-fimbriated strain E. coli AAEC191A(pPKL4). NO production was determined as nitrite production in cell culture medium. Studies of nuclear factor-kappaB (NF-kappaB) binding to the iNOS promoter and reverse transcriptase-polymerase chain reaction of iNOS mRNA were performed to investigate iNOS gene activation in response to uropathogenic E. coli. The effect of interleukin (IL)-6, IL-8 and transforming growth factor-beta on NO production was also examined.

RESULTS

E. coli per se failed to induce NO production and iNOS mRNA in A498 cells. However, in combination with interferon-gamma AD110 and the type 1-fimbriated strain caused a small increase in NO production and iNOS mRNA. AD110 stimulated A498 cells demonstrated weak binding of NF-kappaB to a human iNOS promoter sequence. IL-6, IL-8 and transforming growth factor-a did not affect NO production in A498 cells.

CONCLUSIONS

Uropathogenic bacteria are weak inducers of human uroepithelial iNOS, which may be related to insufficient binding of NF-kappaB to iNOS promoter. The uroepithelial iNOS response did not appear to be regulated by proinflammatory cytokines.

Prostaglandin E2 production and cyclooxygenase-2 induction in human urinary tract infections and bladder cancer

PURPOSE

Increased prostaglandin production correlates positively with cancer risk and cyclooxygenase (COX)-2, the inducible rate limiting enzyme for prostaglandin synthesis, is elevated in bladder cancer cases. Urinary prostaglandin levels and COX-2 expression in urine particulates may increase in urogenital cancer, including bladder cancer, and with infectious and inflammatory processes, including urinary tract infections and that resulting from bacillus Calmette-Guerin (BCG) treatment for bladder cancer.

MATERIALS AND METHODS

Urinary prostaglandin E2 levels were measured in patients with a urinary tract infection before and after treatment, urogenital cancer (including bladder cancer), bladder cancer in remission and bladder cancer with BCG treatment. COX-1 and COX-2 mRNA and protein were assessed in the human ureter, in normal human bladder muscle and urothelium, and in urine particulates from patients with urinary tract infections, bladder cancer and bladder cancer with BCG treatment.

RESULTS

COX-1 protein, and mRNA and COX-2 mRNA were expressed in the ureter, and bladder muscle and urothelium. Urinary prostaglandin E2 levels and COX-2 protein expression in urine particulates were elevated in patients with urinary tract infections and with bladder cancer compared with age matched controls. Successful treatment for urinary tract infections and bladder cancer lowers urinary prostaglandin E2 levels. Urinary prostaglandin E2 and COX-2 protein levels are elevated during BCG treatment.

CONCLUSIONS

Increased urinary prostaglandin E2 production and COX-2 protein expression correlate with urogenital cancer, urinary tract infections and inflammatory processes, such as those induced by BCG. Patients in whom urinary tract infection was treated with antibiotics or in whom bladder cancer is in remission have reduced urinary prostaglandin E2 compared with those who have active disease.

Comparison of three chromogenic agar plates for isolation and identification of urinary tract pathogens

OBJECTIVE

To comparatively assess the performance of three chromogenic agar plates, CPS ID2, Chromogenic UTI, and USA, for the detection and enumeration of all urinary tract pathogens and the direct identification of Escherichia coli, Proteus mirabilis and Enterococcus spp.

METHODS

Two hundred and forty-three urine specimens prospectively collected from hospitalized patients were randomly inoculated in parallel on the three media.

RESULTS

Of the 243 urine specimens, 235 yielded positive cultures, of which 151 were pure cultures and 84 were mixed cultures. CPS ID2, Chromogenic UTI and USA agar gave detection rates of 99.1%, 97.1% and 96.6%, respectively. The main difference in non-detection between CPS ID2 agar and the two new media concerned Staphylococcus spp. strains. Based on the total number of strains detected (n = 348), the total identification rates of E. coli, P. mirabilis and Enterococcus spp. on CPS ID2 agar, Chromogenic UTI agar and USA agar were 60.3%, 61.2% and 59.2%, respectively.

CONCLUSION

The detection rates and identification rates of the three media were very close and only minor differences were noted. The lower detection rates for Chromogenic UTI and USA were mainly due to their lesser ability to support growth of Staphylococcus spp.

Characterization of blaCMY-11, an AmpC-type plasmid-mediated beta-lactamase gene in a Korean clinical isolate of Escherichia coli

We report the description of a new plasmid-encoded AmpC-type beta-lactamase gene (bla(CMY-11)) from Escherichia coli K983802.1 that was isolated from a patient in South Korea suffering from a urinary tract infection. Antibiotic susceptibility testing, plasmid analysis, pI determination, transconjugation and Southern blot analysis were carried out to investigate the resistance mechanism to cefoxitin. PCR, sequencing and sequence analysis were used to identify and analyse the beta-lactamase gene (bla(CMY-11)) responsible for the cefoxitin resistance. CMY-11 and bla(CMY-11) are compared with other class C beta-lactamases and their genes to determine phylogenetic relationships. The cefoxitin-resistance phenotype of E. coli K983802.1 reflects the presence of a large plasmid [pYMG-2 (130 kb)]. A beta-lactamase with a pI value of 8.0 from a transconjugant of E. coli K983802.1 was identified by isoelectric focusing. A 1478 bp DNA fragment from pYMG-2 containing bla(CMY-11) was sequenced and an open reading frame coding for a 382 amino acid peptide (CMY-11) was found. Phylogenetic analysis clearly shows that bla(CMY-11) belongs to the group of ampC-related bla genes. It is likely that bla(CMY-11) evolved from bla(CMY-1) via bla(CMY-10).

Differential expression of uterine NO in pregnant and nonpregnant rats with intrauterine bacterial infection

Previous studies have demonstrated that nitric oxide (NO) is involved in the uterine host defense against bacterial infection. In nonpregnant rats, NO production in the uterus was shown to be lower, and inducible NO synthase (NOS) expression was undetectable. However, studies in pregnant rats show abundant expression of inducible NOS with significant elevation in NO production in the uterus. We have recently reported that intrauterine Escherichia coli infection caused a localized increase in uterine NO production and inducible NOS expression in the nonpregnant rat. In our present study, we examined whether the uterine NO production, NOS expression, and uterine tumor necrosis factor-alpha protein are increased in pregnant rats with intrauterine pathogenic Escherichia coli infection. Unlike the nonpregnant state, the NO production in the infected uterine horn of pregnant rats was not significantly elevated after bacterial inoculation compared with the contralateral uterine horn. The expression of uterine NOS (types II and III) also did not show significant upregulation in the infected horn. This is in contrast to that in nonpregnant animals, in which type II NOS was induced in the uterus on infection. Moreover, intrauterine infection induced an elevated expression of tumor necrosis factor-alpha protein in the infected horn both of nonpregnant and of pregnant rats. These data suggest that the sequential stimulation of NOS expression, especially the inducible isoform, and generation of uterine NO are lacking during pregnancy despite an elevated tumor necrosis factor-alpha after infection. In summary, NO synthesis response may be maximal at pregnancy, and infection may not further induce the NO system. Present studies, together with our previous report that intrauterine infection-induced lethality in pregnancy rats was amplified with the inhibition of NO, suggest that pregnancy is a state predisposed for increased complications associated with intrauterine infection and that the constitutively elevated uterine NO during pregnancy may help contain or even reduce the risk of infection-related complications.

Catheter associated urinary tract infection and encrustation

This paper examines the relationship between urinary pH, infection and urinary catheter encrustation and discusses the current management and problems of catheter associated urinary infection and encrustation.

Urinary tract infection: detection of Escherichia coli antigens in human urine with an ELIEDA immunoenzymatic assay

Escherichia coli is the most common causative agent of urinary tract infection (UTI), and diagnosing this infection usually relies on bacteriologic methods. Nevertheless, screening methods can be useful for a rapid presumptive diagnosis even though some of these screening methods have low sensitivity or are expensive. To investigate a possible new alternative approach, an antigen-based immunoassay--enzyme-linked immunoelectrodiffusion assay (ELIEDA)--was standardized for screening for this bacterial infection. Combining counter-immunoelectrophoresis with an immunoenzymatic assay, the ELIEDA requires concentrated urine specimens, a cellulose acetate membrane, polyclonal antibodies to E. coli raised in rabbits, and peroxidase-labeled sheep antibodies to rabbit immunoglobulin G (IgG). This ELIEDA technique was evaluated using 244 urine specimens, 76 of them with E. coli, 47 with heterologous bacteria, and 121 without bacteria. In comparison to bacteriologic methods, the sensitivity, specificity, and positive and negative predictive values for the ELIEDA were 93.4%, 98.2%, 95.9%, and 97.1%, respectively. The data obtained suggest that this assay is useful for routine diagnostic screening for UTI caused by E. coli. In addition, since the ELIEDA stained membranes can be stored, this assay makes retrospective studies possible.

[Enzymuria and urinary tract infection]

Urinary tract infection (UTI) can lead to kidney damage. The analysis of urinary enzyme activities is a sensitive, non-invasive method to recognise renal tubular lesions. The most important enzymes for kidney diagnosis, pathomechanism of urinary enzyme activity changes in the course of UTI and other factors influencing enzyme excretion are described. Interpretation of enzymuria, its clinical significance for kidney damage diagnosis and prognosis of disease are presented.

Detection of urinary tract infections by reduction of nitroblue tetrazolium

BACKGROUND

Nitroblue tetrazolium (NBT) reduction to formazan has been used as a marker for nitric oxide synthase (NOS). Since inducible NOS activity is elevated in urine from patients with urinary tract infections (UTIs), we investigated the accuracy of NBT reduction as an early predictor of UTIs and quantified the relationship between inducible NOS and NBT.

METHODS

Urine samples from 434 patients were screened for the presence of UTIs with leukocyte-esterase and nitrite dipsticks and with NBT reduction. The rapid screening results from each test were compared to urine culture results. In addition, NBT reduction parameters were measured in urine pellet at 595 nm after incubation with one of four factors: NOS cofactors, NOS inhibitors, NADH, or superoxide dismutase/catalase.

RESULTS

As a urine screening test for UTIs, NBT reduction was more sensitive with a higher negative predictive accuracy than the nitrite dipstick. NBT reduction also was more specific with a higher positive predictive accuracy and negative predictive accuracy than the leukocyte-esterase dipstick. In infected urine pellet, both NADPH, a NOS cofactor, and NADH increased NBT reduction. Superoxide dismutase/catalase decreased NBT reduction.

CONCLUSIONS

Although NOS may not be the only NBT reducing enzyme, rapid, visible reduction of NBT is induced in urine from patients with UTIs.

Bacterial infection induces nitric oxide synthase in human neutrophils

The identification of human inflammatory cells that express inducible nitric oxide synthase and the clarification of the role of inducible nitric oxide synthase in human infectious or inflammatory processes have been elusive. In neutrophil-enriched fractions from urine, we demonstrate a 43-fold increase in nitric oxide synthase activity in patients with urinary tract infections compared with that in neutrophil-enriched fractions from noninfected controls. Partially purified inducible nitric oxide synthase is primarily membrane associated, calcium independent, and inhibited by arginine analogues with a rank order consistent with that of purified human inducible nitric oxide synthase. Molecular, biochemical, and immunocytochemical evidence unequivocally identifies inducible nitric oxide synthase as the major nitric oxide synthase isoform found in neutrophils isolated from urine during urinary tract infections. Elevated inducible nitric oxide synthase activity and elevated nitric oxide synthase protein measured in patients with urinary tract infections and treated with antibiotics does not decrease until 6-10 d of antibiotic treatment. The extended elevation of neutrophil inducible nitric oxide synthase during urinary tract infections may have both antimicrobial and proinflammatory functions.

Nitric oxide synthase induction with renal transplant rejection or infection

Nitric oxide (NO) is readily oxidized to nitrate and nitrite and NO activates guanylyl cyclase, increasing cyclic GMP levels. To determine if nitric oxide synthase (NOS) is present in urine collected daily from patients following renal transplantation, we evaluated NOS activity in the leukocyte-rich particulate fraction and measured nitrate, nitrite, and cyclic GMP levels in the supernatant fraction of the urine. Reverse transcriptase-PCR and cDNA sequencing confirmed the presence of inducible NOS (iNOS) in cells obtained from the urine of renal transplant patients with rejection. NOS activity was elevated significantly in renal transplant patients with rejection (6.40 +/- 1.47 pmol citrulline/min/mg protein) or with urinary tract infection (29.56 +/- 11.00 pmol citrulline/min/mg protein), when compared to post-renal transplantation patients without rejection or urinary tract infection (0.51 +/- 0.21 pmol citrulline/min/mg protein). Nitrate levels increased in renal transplant patients with rejection and nitrite levels increased in renal transplant patients with urinary tract infection (UTI). Cyclic GMP levels increased with both rejection and UTI. This study demonstrates the presence of NOS activity and inducible NOS-mRNA in cells isolated from the urine of patients undergoing renal allograft rejection.

[Clinical evaluation of biapenem (L-627) in children]

Twenty-four children were treated with biapenem (L-627) and the clinical efficacy and side effects were evaluated. The ages of the patients ranged from two months to 11.5 years and their body weights from 5.9 to 43.5 kg. Doses given were 5.5-12.4 mg/kg every 8 hours for 2.67 to 11.33 days. Those patients who responded well to L-627 treatment included 11 children with pneumonia, 1 with scarlet fever, 1 with cervical lymphadenitis, 2 with cellulitis, 6 with urinary tract infection. Among 21 children, the results were excellent in 13 and good in 8. The drug was well tolerated, although slightly elevated serum concentrations of transaminases occurred in 2 patients among the 24 patients.

Significance of elevated levels of serum creatine phosphokinase in febrile diseases: a prospective study

The incidence and significance of elevated serum levels of creatine phosphokinase (CPK) in febrile diseases were studied prospectively in all patients admitted with fever to a department of medicine during 1 year. High serum CPK levels were detected in 70 (28%) of 247 febrile patients but in only six (6%) of 105 afebrile control patients (P = .0001). Elevated CPK levels were not related to any specific diagnosis. Logistic regression analysis identified five factors that correlated both significantly and independently with elevation of CPK values: increased blood urea nitrogen level, low serum phosphate level, a stuporous or comatose state, tremor, and muscle tenderness. Myoglobinuria, detected in 14 patients, was predictive of a fatal outcome, but a high CPK level by itself was not an independent correlate of mortality. In summary, CPK elevation is not uncommon in febrile diseases, but because it does not reflect a specific etiology it does not necessarily indicate that an extensive diagnostic work-up is required.

[Variations in the excretion of N-acetyl-glucosaminidase in the first year of life]

We have studied 122 patients, all younger than 12 months of age, to whom we check the N-acetylglucosaminidase/creatinine (NAG/creatinine) ratio in the first morning urine. The NAG/creatinine values were decreasing with age increase of the patients, being significantly different (p less than 0.001) in the younger 3 months of age comparative with the older than six months of age. The NAG/creatinine values were inversely correlated with age, height and weight. We have made normal values percentils of the NAG/creatinine ratio for each age group.

N-acetyl-beta-glucosaminidase in the localization of the site of urinary tract infections

Excretion of N-acetyl-beta-glucosaminidase was measured in 57 patients with urinary tract infections and in 19 normal subjects. The normal range was 0.17 to 1.16 iu/mmol creatinine. The mean NAG/creatinine ratio was 3.11 in 28 patients with upper, and 1.14 in 21 patients with lower urinary tract infection (p = 0.0006). However, even among those clinically defined as having lower urinary tract infections, 18% had NAG/creatinine ratios above the normal range. The mean NAG/creatinine ratio of 8 patients with lower urinary tract symptoms who had underlying uronephrological diseases/systemic diseases capable of causing nephropathy was intermediate between the value obtained in patients with upper, and that observed in patients with lower urinary tract infections.

Studies on beta-lactamases from Escherichia coli isolated from urinary tract infections

The beta-lactamase types present in 75 ampicillin and carbenicillin resistant E. coli were characterized using isoelectric focusing (IEF). The strains were isolated from patients with urinary tract infections from two geographically different areas of Denmark: 38 strains from Copenhagen and 37 strains from North Jutland. For 19 of the strains from Copenhagen and 18 of the strains from North Jutland, their beta-lactamase activity against nitrocefin and ampicillin, carbenicillin, benzylpenicillin, cloxacillin and cephaloridine was examined by a micro-iodometric and an UV-spectrophotometric assay. The strains from Copenhagen showed greater activity (p less than 0.001) against nitrocefin than the strains from North Jutland. The rate of hydrolysis of ampicillin was greater for the strains from Copenhagen than for the strains from North Jutland. Ninety-three per cent of the strains produced plasmid-mediated beta-lactamases, of which the most prevalent, TEM-1, was produced by 97 per cent of these strains, and OXA-1 by 3 per cent.

[NAG (N-acetyl-beta-D-glucosaminidase)--a sensitive marker for disorders of kidney function]

In a clinical study we tested the use of the lysosomal enzyme NAG as a parameter of kidney function. Following prospective randomization, we examined NAG excretion during cisplatin treatment with/without nephroprotection, after intravenous urography with ionic/non-ionic contrast media, during lower/upper urinary tract infections and before/after extracorporeal shockwave lithotripsy for intrarenal calculi (first-generation equipment used). Measurements were performed in 3-h urine specimens and in urine collected over 24 h, using a simple method of analysis. A correlation between NAG leakage and functional disorder of the renal tubular cells seemed likely on the basis of additional clinical and experimental data. Increases, in some cases dramatic, in NAG excretion were observed after the administration of cisplatin and ionic contrast media, in acute pyelonephritis, and after extracorporeal shockwave lithotripsy. However, the increase in NAG excretion was less impressive during cisplatin therapy when nephroprotective amino acids were infused, and in the urography group when non-ionic contrast media were used. Infections of the lower urinary tract did not increase NAG excretion. The results indicate that NAG is a sensitive marker of occult renal dysfunction, which can be checked by non-invasive techniques and can be used in a clinic setting to detect functional disorders of the kidney.

Staphylococcus saprophyticus urease: characterization and contribution to uropathogenicity in unobstructed urinary tract infection of rats

We studied the biochemical properties of the urease of Staphylococcus saprophyticus and the possible role of the urease in experimental urinary tract infections. For this purpose, the nonhemagglutinating and nonadherent strain 9325, which was isolated from a case of symptomatic urinary tract infection, was used. The urease was shown to have a Km of 6.64 mM urea and a Vmax of 4.59 mumol NH3.min-1.mg-1. The enzyme was inhibited by acetohydroxamic acid in a noncompetitive manner. By means of Sephacryl S-300 column chromatography, we determined a mean molecular weight (+/- standard error of the mean) of 420,000 +/- 16,000. To assess the contribution of S. saprophyticus urease to uropathogenicity, a urease-negative mutant was constructed by nitrosoguanidine mutagenesis. In the rat model of ascending unobstructed urinary tract infection, higher numbers of CFU.gram of tissue-1 and more-severe lesions were detected with the parent strain. Moreover, bladder stones were found in animals infected with the urease-positive strain only. Interestingly, the difference in mean bacterial counts of the bladders was found to be significant by the Wilcoxon two-sample test (P less than 0.05), whereas that between the kidney bacterial counts was not. Immunoblot studies revealed a faint antibody response in rats infected with the mutant strain, although bacteria could still be detected in the kidneys after 7 days. Sera of animals challenged with the parent strain reacted strongly with many antigens of S. saprophyticus. Our data indicate that urease is a major factor for invasiveness of S. saprophyticus, especially in the tissue of the bladder, whereas persistence in the urinary tract and nephropathogenicity of this organism are governed by factors other than urease.

Urinary alanine-aminopeptidase (AAP) excretion in patients with urinary tract infection treated with ceftazidime (CAZ) or cefotaxime (CTX) plus tobramycin (TOB)

It is well known that some antibiotics are particularly nephrotoxic. In the present study we investigated kidney function and AAP excretion (as an index of nephrotoxicity) in patients with urinary tract infection treated with CAZ or CTX plus TOB. The main cause of infection was E. coli in both treated groups. After 10 days of treatment similar beneficial effects were stated in both groups. At the end of treatment urinary AAP excretion in both groups was higher than before treatment. Despite a significant increase in urinary AAP in only one patient of each group, the serum creatinine level rose by more than 45 mumol/l. Monitoring of urinary AAP may be useful in early detection of nephrotoxicity caused by antibiotics.

Urinary lactic acid dehydrogenase activity and the site of urinary tract infections

A report that elevated urinary lactic acid dehydrogenase (LDH) isoenzyme 5 activity is a reliable tool for separating patients with upper from those with lower urinary tract infections (UTIs) led us to study urinary LDH enzyme activity in girls having bladder washout studies to localize the site of infection. Urinary LDH isoenzyme 5 activity in 64 instances of lower UTI was 16.1 +/- 3.3%, a value not significantly different than that of 18.2 +/- 12.6% found in 26 instances of upper tract infection (t = 0.8726, P = 0.1928). The data show that LDH isoenzyme 5 activity is of no value for localization of the site of a UTI. The data of these studies also showed that urinary LDH enzyme activity clearly separates girls with UTIs from those without infections, but it is unlikely that this finding will be of value in diagnosis or management.

[Behavior of certain forms of enzymuria in subjects treated with pipemidic acid]

Three groups of subjects (I with infections of the lower urinary ways; II with chronic pyelonephritis; III healthy controls) were treated with pipemidic acid for 10 consecutive days and the behaviour of their urinary NAG and AAP was studied. It was discovered that the healthy group and the patients with infections of the lower urinary ways showed no significant variations in the urinary activity of the two enzymes following the administration of pipemidic acid. However there was a distinct reduction in both enzymes in patients with chronic pyelonephritis who presented demonstrable bacterial sensitivity to the drug. Apart from the fact that it produces no nephrotoxic effects at least in the doses used and for the treatment period adopted, the drug is therefore considered to reduce renal inflammation that is beneficial to individuals with chronic interstitial nephropathy.

Leukocyte esterase activity in the rapid detection of urinary tract and lower genital tract infections in obstetric patients

Infections of the vagina and urinary tract are important problems for the obstetrician. Examination of the vaginal discharge and urine for the presence of leukocytes is an important part of the evaluation for vaginitis and urinary tract infections. Neutrophils contain several esterases that are not present in serum, urine, or vaginal secretions. These esterases are not influenced by bacteria, commonly used drugs, or variable compositions of urine or vaginal secretions. A prospective study was performed to assess the sensitivity and specificity of leukocyte esterase activity as measured by dipstick (Chemstrip 9, Biodynamics) for the prediction of vaginitis and urinary tract infections during pregnancy. Results were compared with those obtained from potassium hydroxide smears, wet preps, and urine cultures. The vaginal discharge and urine of 65 patients was tested for leukocyte esterase activity on their initial OB visit. Leukocyte esterase was 100% sensitive and 100% specific for detecting urinary tract infections. It was 100% sensitive and 90% specific for predicting vaginal infections. Trichomonas infections accounted for the positive leukocyte esterase results when the urine culture was negative. On the basis of this study we believe that leukocyte esterase activity is sufficiently sensitive and specific to permit use of this test as a rapid and inexpensive screening procedure for vaginitis and urinary tract infections.

Urinary lactate dehydrogenase isoenzyme analysis in adult population

This investigation was a systemic study on an adult population of urinary lactate dehydrogenase (LDH) isoenzyme analysis for the distinction between upper and lower urinary tract infections. The study included 160 urine samples from patients and healthy individuals. On the basis of clinical symptoms, urinary bacterial colony counts, renal function tests and radiologic findings, the adults were divided into pyelonephritis group, cystitis group, pelvic lesion group, and control group. This technique correctly identified 23 of 26 patients with pyelonephritis by the presence of elevated LDH-V (over 10 percent) and all of 12 patients with cystitis by the presence of elevated LDH-I (over 60 relative units) but low LDH-V (below 10 percent or lower than LDH-I). In the pelvic group, the results of eight patients were consistent with cystitis and four with pyelonephritis. Our study confirms the sensitivity and specificity of the LDH isoenzyme technique for the differential diagnosis of urinary tract infection on adult patients and is consistent with previous studies on pediatric patients. However, one should be cautious to interpret the results of LDH isoenzymogram before extra-urinary tract lesions are excluded.

A new alkaline phosphatase isoenzyme abnormality

We report on a new alkaline phosphatase isoenzyme abnormality occurring as an incidental finding in a male infant aged 4 months. Isoenzyme electrophoresis on cellulose acetate showed a prominent, diffuse alkaline phosphatase staining band in the alpha 1-globulin position together with a second band in the alpha 2/beta region and minor 'trailing' in the intermediate alpha 2 region. Normal liver and bone alkaline phosphatase were absent and intestinal phosphatase was not detected. On acrylamide gel electrophoresis a marked origin band was detectable suggesting the presence of high molecular weight enzyme. In addition, a series of compact bands in the alpha 2/beta position was present cathodal to the usual liver and bone isoenzymes. Total alkaline phosphatase activity was marginally elevated and was heat labile, L-phenylalanine resistant and partially L-homoarginine and L-leucine sensitive.

Comparison of moxalactam and gentamicin in the treatment of complicated urinary tract infections

Moxalactam and gentamicin were compared in a prospective, randomized study of 49 hospitalized patients with complicated urinary tract infections. Patients received parenteral moxalactam, 250 mg every 12 h, or gentamicin, 1 mg/kg every 8 h. The average duration of therapy (moxalactam, 7.5 days; gentamicin, 8.6 days) was similar for both groups. Sixty-two percent of patients treated with moxalactam and 57% of those receiving gentamicin were cured of their infection, as defined by a negative culture after therapy. No side effects required discontinuation of either drug. An enterococcus caused two superinfections and three reinfections in patients treated with moxalactam. Moxalactam resistance developed in Pseudomonas aeruginosa isolates from three patients treated with moxalactam. Moreover, two of these isolates showed decreased susceptibility to gentamicin, tobramycin, and amikacin. An additional 10 patients with gentamicin-resistant but moxalactam-susceptible isolates were treated with moxalactam. Forty percent of these patients were cured of their infections. Moxalactam appears to be a safe, effective drug for complicated urinary tract infections caused by susceptible bacteria, including those resistant to gentamicin. However, patients receiving moxalactam should be carefully monitored to detect enterococcal superinfections or development of resistance to moxalactam in isolates of P. aeruginosa.

Correlation of urinary lactic dehydrogenase with polymorphonuclear leukocytes in urinary tract infections in patients with spinal cord injuries

A number of indirect methods have been developed to determine the site of urinary tract infection, including the measurement of LDH in urine [1]. Although LDH has been thought to be from the kidneys, it has also been noted that leukocytes could contribute LDH isoenzymes 4 and 5 [2]. Seventeen patients with injured spinal cords and significant bacteriuria were included in this study. Urine specimens obtained by urethral catheter were cultured, and PMNLs identified with Sternheimer-Malbin stain were counted in a hemacytometer. A positive test for antibody-coated bacteria and the lack of patient response to five to 10 days of antibiotic therapy were used as an indication of upper urinary tract infection. Levels of LDH isoenzymes 4 and 5 (cathodal) correlated with the number of PMNLs in the urine (r = 0.63, P less than 0.01). There was no correlation of PMNLs with LDH isoenzymes 1 and 2 (r = 0.18). In addition, there was no correlation of LDH isoenzymes 4 and 5 with the level of urinary tract infection. These results suggest that the PMNLs in the urine are the source of the LDH isoenzymes 4 and 5.

Urinary lactic dehydrogenase and serum C-reactive protein as means of localizing the site of urinary tract infection in patients with ileal conduits

Many patients with ileal conduit urinary diversion have infected urine but far fewer have clinical pyelonephritis. A noninvasive diagnostic test to distinguish renal bacteriuria from conduit colonization in these patients would seem desirable. Urine total lactic dehydrogenase and lactic dehydrogenase isoenzymes, and serum C-reactive protein have been useful to distinguish pyelonephritis from cystitis in patients with intact urinary tracts. We used these tests in patients with ileal conduits who had urine containing more and less than 10(5) organisms per ml. All patients had elevated urine total lactic dehydrogenase-5 isoenzyme, and serum C-reactive protein. No statistically significant difference in any of these parameters existed between the groups. These results may indicate that all patients with conduits have pyelonephritis but only intermittently demonstrate bacteriuria, or that the conduit mucosa contributes lactic dehydrogenase to the urine. However, it does not appear that these tests alone can distinguish accurately renal bacteriuria from conduit colonization.

[Clinical significance of bacterial beta-lactamase production in the treatment of urinary tract infections with oral beta-lactam-antibiotics]

In 649 urological patients with urinary tract infections (UTI) a total of 1114 bacterial strains were isolated and their beta-lactamase production was investigated by a qualitative, micro-iodometric method. Approximately 40% of all strains, 33% of E. coli species and 8% of Proteus mirabilis species were enzyme producers. All of the isolates of E. coli and Proteus mirabilis defined as non-producers were sensitive to ampicillin and cephalothin in the agar diffusion test. The beta-lactamase producers of these two species did not show the same pattern: almost all of them were ampicillin-resistant, but most were cephalothin-sensitive. The other species were all found to be either producers or non-producers. Therapeutic comparisons in altogether 138 UTI patients treated with ampicillin or cephalexin, two antibiotics with different beta-lactamase stability, confirmed the positive correlation between enzyme production and therapeutic failure in both groups. Cephalexin, however, tended to be more effective than ampicillin against enzyme-producing species.

Increased urine angiotensin I converting enzyme activity in patients with upper urinary tract infection

Angiotensin converting enzyme (ACE) is present within the brush border of the tubular cell of the kidney. Since it has a high molecular mass, ACE activity of urine most probably derives only from tubular cells, thus suggesting the potential usefulness of ACE determination as an index of tubular damage. When assayed with the method described, ACE is optimally active at pH 8 with a calcium concentration exceeding 0.75 mmol/l urine, and is chloride independent. Urine dialysis has no effect on ACE activity. ACE is stable at 4 degrees C for 10 days, but it is inactivated by repeated thawing and freezing. The presence of leucocytes and bacteria does not interfere with the assay. Urine ACE activity was evaluated in patients with upper and lower urinary tract infection, nephrolithiasis, chronic glomerulonephritis and essential hypertension and was found to be significantly increased only in patients affected by upper urinary tract infection and nephrolithiasis.