A clinical evaluation of a sensor to detect blockage due to crystalline biofilm formation on indwelling urinary catheters.

OBJECTIVE: To test the performance and acceptability of an early warning sensor to predict encrustation and blockage of long-term indwelling urinary catheters. PATIENTS AND METHODS: In all, 17 long-term indwelling catheter users, 15 'blockers' and two 'non-blockers' (controls) were recruited; 11 participants were followed prospectively until catheter change, three withdrew early and three did not start. Two sensors were placed in series between the catheter and the urine bag at catheter change. The sensor nearest the bag was changed at the same time as the bag change (weekly); the sensor nearest the catheter remained in situ for the duration of the catheter's life. Bacteriology and pH determinations were performed on urine samples at each bag, sensor and catheter change. The colour of the sensors was recorded daily. On removal, each sensor and the catheter were examined for visible evidence of encrustation and blockage. Participants were asked to keep a daily diary to record colour change and any other relevant observations and to complete a psychosocial impact of assistive devices tool at the end of the study. Participants and carers/healthcare professionals (when involved in urine bag or catheter change) were asked to complete a questionnaire about the sensor. RESULTS: Urease-producing bacteria were isolated from seven of the 14 patients (including early withdrawals; P. mirabilis in four, Morganella or Providencia in three). In six of the seven patients the sensors turned blue-black; two of these were early withdrawals, two went to planned catheter change (one of these was recruited as a 'non-blocker') and three had catheter blockage. The number of days of catheterisation before blockage was 22, 23 and 25 days, and the sensor changed colour within 24-48 h after insertion. The urine mean (range) pH of the sensors that turned blue-black was 7.6 (5.5-9.0) and of the sensors that remained yellow 6.1 (5.1-7.5). The sensor was generally well-received and was positive in the psychosocial assessment. CONCLUSIONS: The sensor is a useful indicator of urine pH and of the conditions that lead to catheter blockage. It may be particularly useful for new indwelling catheter users. To be a universally acceptable predictor of catheter blockage, the time from sensor colour change to blockage needs to be reduced.

The human urinary microbiome; bacterial DNA in voided urine of asymptomatic adults.

The urinary microbiome of healthy individuals and the way it alters with ageing have not been characterized and may influence disease processes. Conventional microbiological methods have limited scope to capture the full spectrum of urinary bacterial species. We studied the urinary microbiota from a population of healthy individuals, ranging from 26 to 90 years of age, by amplification of the 16S rRNA gene, with resulting amplicons analyzed by 454 pyrosequencing. Mid-stream urine (MSU) was collected by the "clean-catch" method. Quantitative PCR of 16S rRNA genes in urine samples, allowed relative enumeration of the bacterial loads. Analysis of the samples indicates that females had a more heterogeneous mix of bacterial genera compared to the male samples and generally had representative members of the phyla Actinobacteria and Bacteroidetes. Analysis of the data leads us to conclude that a "core" urinary microbiome could potentially exist, when samples are grouped by age with fluctuation in abundance between age groups. The study also revealed age-specific genera Jonquetella, Parvimonas, Proteiniphilum, and Saccharofermentans. In conclusion, conventional microbiological methods are inadequate to fully identify around two-thirds of the bacteria identified in this study. Whilst this proof-of-principle study has limitations due to the sample size, the discoveries evident in this sample data are strongly suggestive that a larger study on the urinary microbiome should be encouraged and that the identification of specific genera at particular ages may be relevant to pathogenesis of clinical conditions.

Antiretroviral combination therapy for HIV infection.

Since the introduction of highly active antiretroviral therapy, studies have demonstrated declining morbidity and mortality rates among people with HIV. This is largely because antiretroviral combination therapy can suppress plasma HIV viral load below detectable limits and cause gradual elevation in CD4 cell counts, resulting in improved immune status for responsive patients who are compliant with therapy. These drugs, however, are not without side-effects, both general and oral, and this review draws attention to some of the interactions of the drugs used to treat HIV infection with drugs used in dentistry.

Frequent translocations occur between low copy repeats on chromosome 22q11.2 (LCR22s) and telomeric bands of partner chromosomes.

The chromosome 22q11.2 region is susceptible to rearrangements, mediated by low copy repeats (LCR22s). Deletions and duplications are mediated by homologous recombination events between LCR22s. The recurrent balanced constitutional translocation t(11;22)(q23;q11) breakpoint occurs in an LCR22 and is mediated by double strand breaks in AT-rich palindromes on both chromosomes 11 and 22. Recently, two cases of a t(17;22)(q11;q11) were reported, mediated by a similar mechanism (21). Except for these constitutional translocations, the molecular basis for non-recurrent, reciprocal 22q11.2 translocations is not known. To determine whether there are specific mechanisms that could mediate translocations, we analyzed cell lines derived from 14 different individuals by genotyping and FISH mapping. Somatic cell hybrid analysis was carried out for four cell lines. In five cell lines, the translocation breakpoints occurred in the same LCR22 as for the t(11;22) translocation, suggesting that similar molecular mechanisms are responsible. An additional three occurred in other LCR22s, and six were in non-LCR22 regions, mostly in the proximal half of the 22q11.2 region. The translocation breakpoints on the partner chromosomes were all located in the telomeric bands, proximal to the most telomeric unique sequence probe, in eight cell lines and distal to those loci in six. Therefore, several of the breakpoints were found to occur in the vicinity of highly dynamic regions of the genome, 22q11.2 and telomeric bands. We hypothesize that these regions are more susceptible to breakage and repair, resulting in translocations.