Prevalence and mobility of integrative and conjugative elements within a Streptomyces natural population.

Horizontal Gene Transfer (HGT) is a powerful force generating genomic diversity in bacterial populations. HGT in Streptomyces is in large part driven by conjugation thanks to plasmids, Integrative and Conjugative elements (ICEs) and Actinomycete ICEs (AICEs). To investigate the impact of ICE and AICE conjugation on Streptomyces genome evolution, we used in silico and experimental approaches on a set of 11 very closely related strains isolated from a millimeter scale rhizosphere population. Through bioinformatic searches of canonical conjugation proteins, we showed that AICEs are the most frequent integrative conjugative elements, with the central chromosome region being a hotspot for integrative element insertion. Strains exhibited great variation in AICE composition consistent with frequent HGT and/or gene loss. We found that single insertion sites can be home to different elements in different strains (accretion) and conversely, elements belonging to the same family can be found at different insertion sites. A wide variety of cargo genes was present in the AICEs with the potential to mediate strain-specific adaptation (e.g., DNA metabolism and resistance genes to antibiotic and phages). However, a large proportion of AICE cargo genes showed hallmarks of pseudogenization, consistent with deleterious effects of cargo genes on fitness. Pock assays enabled the direct visualization of conjugal AICE transfer and demonstrated the transfer of AICEs between some, but not all, of the isolates. Multiple AICEs were shown to be able to transfer during a single mating event. Although we did not obtain experimental evidence for transfer of the sole chromosomal ICE in this population, genotoxic stress mediated its excision from the chromosome, suggesting its functionality. Our results indicate that AICE-mediated HGT in Streptomyces populations is highly dynamic, with likely impact on strain fitness and the ability to adapt to environmental change.

Mining the Biosynthetic Potential for Specialized Metabolism of a Streptomyces Soil Community.

The diversity and distribution of specialized metabolite gene clusters within a community of bacteria living in the same soil habitat are poorly documented. Here we analyzed the genomes of 8 Streptomyces isolated at micro-scale from a forest soil that belong to the same species or to different species. The results reveal high levels of diversity, with a total of 261 biosynthesis gene clusters (BGCs) encoding metabolites such as terpenes, polyketides (PKs), non-ribosomal peptides (NRPs) and ribosomally synthesized and post-translationally modified peptides (RiPPs) with potential bioactivities. A significant part of these BGCs (n = 53) were unique to only one strain when only 5 were common to all strains. The metabolites belong to very diverse chemical families and revealed that a large diversity of metabolites can potentially be produced in the community. Although that analysis of the global metabolome using GC-MS revealed that most of the metabolites were shared between the strains, they exhibited a specific metabolic pattern. We also observed that the presence of these accessory pathways might result from frequent loss and gain of genes (horizontal transfer), showing that the potential of metabolite production is a dynamic phenomenon in the community. Sampling Streptomyces at the community level constitutes a good frame to discover new biosynthetic pathways and it appears as a promising reservoir for the discovery of new bioactive compounds.

Incontinent ileovesicostomy in the management of neurogenic bladder dysfunction.

AIMS: To report outcome and urodynamic follow-up of incontinent ileovesicostomy in quadriplegic patients with neurogenic bladder. METHODS: Seven patients (five male, two female; mean age, 33.7 yr) with neurogenic bladder underwent ileovesicostomy for management of leakage or complications of chronic catheter drainage. Five had chronic indwelling catheters: three suprapubic and two urethral. Preoperatively, all had upper tract evaluation and videourodynamics. All seven patients had detrusor hyperreflexia. Preoperative detrusor leak point pressures averaged 42.7 cm H(2)O. Two females had intrinsic sphincteric deficiency from prolonged Foley catheter drainage. Ileovesicostomy involves isolation of a 15-20-cm segment of terminal ileum. The proximal 6-8 cm of this segment is opened on the antimesenteric border. The dome of the bladder is opened widely in a transverse manner and the proximal portion of the bowel is sutured onto the bladder. The distal portion of the ileum remains tubularized and becomes the stoma. RESULTS: There were no intraoperative complications. Operative time averaged 159 minutes. Associated procedures included removal of bladder calculus (n = 1), pubovaginal sling (n = 2), and Marshall Marchetti Krantz suspension (n = 1). Mean blood loss was <200 cc in six patients. Mean hospital stay was 8 days. Complications in two patients included: fascial stenosis requiring stoma revision (n = 1), wound infection (n = 1), and postoperative ileus (n = 1). Mean follow-up was 37.4 months. Postoperatively, mean detrusor leak point pressures were 16.7 cm H(2)O (P = 0.0061). Patient satisfaction is high with only one complaint of occasional difficulty fitting the appliance. CONCLUSIONS: Ileovesicostomy is an effective method of urinary drainage in quadriplegic patients. Detrusor leak point pressures were lowered, and upper tracts were preserved. No long-term complications were encountered.

Use of cadaveric fascia lata for closure of bladder exstrophy with diplomyelia.

We describe a technique for the repair of bladder exstrophy using cadaveric fascia lata. The graft is folded in a four-layer configuration, passed through the obturator foramina, and then wrapped and anchored in front of the pubis. The resultant ring-shaped graft is useful when complex deformities preclude proper apposition of the pelvis anteriorly.