Determination of Chlamydia trachomatis prevalence in an asymptomatic screening population: performances of the LCx and COBAS Amplicor tests with urine specimens.
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This study determined the performances of the LCx (Abbott) and COBAS Amplicor (Roche) tests with urine specimens for the detection of Chlamydia trachomatis in an asymptomatic screening population. Randomly selected women and men (age range, 15 to 40 years) registered in 20 general practices in Amsterdam, The Netherlands, were invited to participate in this study. Urine specimens (n = 2, 906; 1,138 specimens from men and 1,717 specimens from women) were tested for C. trachomatis by the COBAS Amplicor (Roche) and LCx (Abbott) tests. Samples which were positive by only one assay were subjected to discrepant analyses by a third assay (in-house plasmid PCR). By the LCx assay C. trachomatis DNA was detected in urine specimens from 46 of 1,717 women and 29 of 1,138 men, while the COBAS Amplicor detected C. trachomatis DNA in 52 and 35 specimens, respectively. When comparing the LCx and COBAS Amplicor tests, 32 test results (20 for women and 12 for men) were discrepant. After discrepant analyses the following sensitivities, specificities, and positive predictive values were found for the LCx and COBAS Amplicor tests: 78.6 versus 98.8%, 99.7 versus 99.9%, and 88.0 versus 95.4%, respectively. No prominent differences were found between men and women with regard to the test performances. After discrepant analyses the overall prevalences of C. trachomatis in women and men were 3.0 and 2.8%, respectively. For both women and men the prevalence in the younger age groups was higher than that in the older age groups. In conclusion, the COBAS Amplicor tests shows better diagnostic characteristics than the LCx assay for the detection of C. trachomatis in urine specimens from an asymptomatic screening population. In this asymptomatic population the overall prevalence of C. trachomatis was 2.9%. (+info)
Identification of genes in an extraintestinal isolate of Escherichia coli with increased expression after exposure to human urine.
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The identification of genes with increased expression in vivo may lead to the identification of novel or unrecognized virulence traits and/or recognition of environmental signals involved in modulating gene expression. Our laboratory is studying an extraintestinal isolate of Escherichia coli as a model pathogen. We had previously used human urine ex vivo to identify the unrecognized urovirulence genes guaA and argC and to establish that arginine and guanine (or derivatives) were limiting in this body fluid (T. A. Russo et al., Mol. Microbiol. 22:217-229, 1996). In this study, we have continued with this approach and identified three additional genes that have increased expression in human urine relative to Luria-Bertani (LB) medium. Expression of ure1 (urine-responsive element) is increased a mean of 47.6-fold in urine but completely suppressed by exogenous glucose. This finding suggests that ure1 is regulated by catabolite repression and that limiting glucose in urine is a regulatory signal. ure1 is present in the E. coli K-12 genome, but its function is unknown. Although disruption of ure1 results in diminished growth in human urine, limiting concentrations of amino acids, nucleosides, or iron (Fe), or changes in osmolarity or pH do not affect the expression of ure1. Therefore, Ure1 appears to have a role independent of the synthesis or uptake of these nutrients and does not appear to be involved in osmoprotection. iroN(E. coli) is a novel E. coli gene with 77% DNA homology to a catecholate siderophore receptor gene recently identified in Salmonella. Its expression is increased a mean of 27.2-fold in urine and is repressed by exogenous Fe and a urinary pH of 5.0. This finding supports the contention that Fe is a limiting element in urine and that alteration of pH can affect gene expression. It is linked to the P-pilus (prs) and F1C fimbrial (foc) gene clusters on a pathogenicity island and appears to have been acquired by IS1230-mediated horizontal transmission. The homologous iroN(E. coli) sequence is significantly more prevalent in urinary tract and blood isolates of E. coli compared to fecal isolates. Last, the expression of ArtJ, an arginine periplasmic binding protein, is increased a mean of 16.6-fold in urine. This finding implicates arginine concentrations as limited in urine and, in combination with previous data demonstrating that argC is important for urovirulence, suggests that the ability of E. coli to synthesize or acquire arginine is important for urovirulence. ure1, iroN(E. coli), and artJ all have increased expression in human blood and ascites relative to LB medium as well. The identification of these genes increases our understanding of regulatory signals present in human urine, blood, and ascites. Ure1, IroN(E. coli), and ArtJ also warrant further evaluation as virulence traits both within and outside the urinary tract. (+info)
Comparison of the epidemiology of bacterial resistance to mecillinam and ampicillin.
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Mecillinam is a new type of beta-lactam antibiotic (an amidinopenicillanic acid) that is particularly active against Enterobacteriaceae and is taken orally as in the form of an ester, pivmecillinam. Assessment of any new antibiotic should include a survey of levels of bacterial resistance and investigation of its capacity to select resistant organisms or harm the commensal flora. Antibiotic resistance patterns of 2,000 Enterobacteriaceae isolated from the urine of patients with significant urinary tract infections were therefore determined. Mecillinam-resistant Enterobacteriaceae were found to be much less common than ampicillin-amoxycillin-resistant organisms both in the community and in hospital patients. Most ampicillin-resistant Enterobacteriaceae from infected urines were susceptible to mecillinam, but the relatively rare mecillinam-resistant organisms were usually resistant to ampicillin and cephaloridine. The fecal flora of 26 healthy volunteers who served as controls or were given repeated courses of therapeutic doses of either ampicillin or pivmecillinam was studied. Pivmecillinam had only a transient effect on the aerobic fecal flora and in contrast to ampicillin did not increase populations of resistant Enterobacteriaceae, which would be a potential hazard to the patient and contaminate the environment. (+info)
In vivo detection of Escherichia coli type 1 fimbrial expression and phase variation during experimental urinary tract infection.
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Adhesion mediated by fimbriae is thought to play an important role in the pathogenesis of urinary tract infections (UTI) by Escherichia coli. The majority of clinical isolates of E. coli from UTI are able to express type 1 fimbriae. However, the importance of these fimbriae as a virulence factor has been controversial. To investigate the expression of type 1 fimbriae in vivo during UTI, mice were transurethrally infected with uropathogenic E. coli C175-94 and type 1 fimbrial expression was determined directly by two independent methods at 2 h, 1 d and 3 d after infection. By use of an assay combining in situ rRNA hybridization and immunofluorescence, all bacterial cells detected in urine, bladders and kidneys from mice sacrificed 1 and 3 d after onset of infection were found to express type 1 fimbriae. In contrast, the majority of cells in the suspension used for infection of mice and specimens from mice sacrificed 2 h after inoculation were found to be non-fimbriated. Similar results were obtained with a PCR assay revealing the orientation of the invertible promoter driving the transcription of type 1 fimbrial genes. Whilst the promoter in both ON and OFF positions could be amplified from the suspension used for infection and specimens from mice sacrificed 2 h after inoculation, at 1 and 3 d after onset of infection only the promoter in the ON orientation could be amplified. These results show that introduction of E. coli C175-94 into the mouse urinary tract leads to markedly enhanced expression of type 1 fimbriae. (+info)
Renal transplantation in patients with urinary diversion: a case-control study.
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BACKGROUND: Renal transplantation in Sweden in patients with ileal conduits or continent reservoirs was investigated in order to compare the outcome with regard to graft and patient survival as compared to controls. METHODS: Patient data from the four transplantation centres in Sweden were collected on: treatment prior to transplantation, time needed for the operative procedure, and postoperative care and outcome in terms of renal function as well as graft and patient survival at 1 and 5 years. The pattern of urinary tract infection was also investigated. Each case with urinary diversion was matched with two non-diabetic controls. RESULTS: Ten male and 12 female cases were found who had received 27 grafts between 1982 and 1996. Five patients had a Kock reservoir and 17 had a Bricker conduit. The time needed for the transplant procedure was significantly longer in the case group. After matching the case group with 54 controls, we found that the renal function was similar in both groups. Graft and patient survival was similar in both groups, over 90% after 1 year. Graft survival was about 70% after 5 years. Postoperative surgical complications in the case group were only seen in a few cases. The pattern of bacteria causing urinary tract infection was slightly different among the patients with ileal conduits or continent reservoirs. CONCLUSION: Patients with ileal conduits or continent reservoirs have similar graft and patient survival rates as the general kidney transplant population. The presence of constant bacteriuria did not adversely affect survival. Prophylactic antibiotic treatment seems not to be warranted. There appears to be no indication for native nephrectomy, except in selected cases. The study did not show any advantage with regard to continent reservoirs vs ileal conduits. (+info)
Urinary catheter management.
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The use of urinary catheters should be avoided whenever possible. Clean intermittent catheterization, when practical, is preferable to long-term catheterization. Suprapubic catheters offer some advantages, and condom catheters may be appropriate for some men. While clean handling of catheters is important, routine perineal cleaning and catheter irrigation or changing are ineffective in eliminating bacteriuria. Bacteriuria is inevitable in patients requiring long-term catheterization, but only symptomatic infections should be treated. Infections are usually polymicrobial, and seriously ill patients require therapy with two antibiotics. Patients with spinal cord injuries and those using catheters for more than 10 years are at greater risk of bladder cancer and renal complications; periodic renal scans, urine cytology and cystoscopy may be indicated in these patients. (+info)
Novel screening method for urine cultures using a filter paper dilution system.
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We have developed a novel method for urine culture for office practice based on the use of filter paper as a solid-phase dilution device. Filtration dilutes and spreads the inoculum onto a solid culture surface. Experiments were conducted to determine the optimum inoculum size, microbial permeability through filter papers, and ability to exclude vaginal epithelial cells. The filter paper dilution system was compared to the standard streak method to detect bacteriuria in specimens submitted to the diagnostic laboratory. The sensitivity and specificity of the filter paper dilution system for detection of high-count (>/=10(4) CFU/ml) gram-negative bacteriuria in 487 urine specimens were 98.2 and 97.4%, respectively. The sensitivity and specificity for gram-positive bacteriuria in 404 urine specimens were 91.2 and 99.2%, respectively. Low-count gram-negative bacteriuria (<10(4) CFU/ml) was detected by the filter paper dilution system in five of nine specimens (55.6%). In addition, the filter paper dilution system was able to detect gram-negative bacteria in 12 of 41 (29.3%) mixed cultures. Lactobacillus and Gardnerella organisms in urine specimens were excluded by the filter paper dilution system. Only three of eight Candida sp. isolates were detected at counts of >/=10(4) CFU/ml. The system has good storage properties and can be inoculated at the point of source without the need for refrigeration or preservatives. It should be a useful screening method for office practice, where members of the family Enterobacteriaceae and staphylococci cause most infections. Standard culture methods are preferred for hospital diagnostic microbiology laboratories, where there is a need to detect yeasts and fastidious microorganisms and to isolate individual colonies from mixed cultures. (+info)
Prevalence of Chlamydia trachomatis in urine of male patients with ankylosing spondylitis is not increased.
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OBJECTIVE: To compare the prevalence of Chlamydia trachomatis infections in ankylosing spondylitis (AS) patients with controls, using DNA amplification assays in urine specimens. METHODS: The prevalence of C trachomatis infections was assessed in 32 male AS patients and 120 age and sex matched controls. Urine specimens were tested by ligase chain reaction and polymerase chain reaction. In addition, blood samples of AS patients were tested on serum antibodies to C trachomatis (IgA and IgG) by a specific peptide based solid phase enzyme immunoassay. A questionnaire was used to assess the differences in sexual behaviour and ethnic origin between the two groups. AS patients were also asked about disease characteristics. RESULTS: No significant differences were found between cases and controls in the prevalence of C trachomatis infections. No associations were found between C trachomatis antibodies and disease characteristics, except for acute anterior uveitis (AAU). Four of eight (50%) AS men positive for IgG had a history of AAU in comparison with three of 24 (12.5%) IgG negative men (OR = 7.0; 95% confidence intervals: 1.1, 44.1). CONCLUSION: The prevalence of Chlamydia trachomatis infections, as detected by commercially available DNA amplification assays in urine specimens, in AS patients is not higher compared with male controls of the same age. However, there seems to be an association between specific antibodies to C trachomatis and AAU. (+info)