Multidisciplinary Implant Rehabilitation of a Patient with Cleidocranial Dysostosis: A Journey from Age 13 to 21.

This clinical report describes the multidisciplinary oral rehabilitation of a teenage female patient with cleidocranial dysostosis, whose treatment was started in her teenage years. The unique challenges of delayed intervention are described in this report, highlighting the surgical, orthodontic, and prosthodontic care the patient received from age 13 to 21. Maintaining as many natural teeth as possible, orthodontically erupting impacted teeth using a mandibular provisional fixed implant prosthesis as anchor, crowning several natural teeth, and rehabilitating edentulous areas with fixed implant restorations provided the patient with esthetic and functional outcomes.

An Analysis of the Epidemic of Klebsiella pneumoniae Carbapenemase-Producing K. pneumoniae: Convergence of Two Evolutionary Mechanisms Creates the "Perfect Storm".

Background: Carbapenem resistance is a critical healthcare challenge worldwide. Particularly concerning is the widespread dissemination of Klebsiella pneumoniae carbapenemase (KPC). Klebsiella pneumoniae harboring blaKPC (KPC-Kpn) is endemic in many areas including the United States, where the epidemic was primarily mediated by the clonal dissemination of Kpn ST258. We postulated that the spread of blaKPC in other regions occurs by different and more complex mechanisms. To test this, we investigated the evolution and dynamics of spread of KPC-Kpn in Colombia, where KPC became rapidly endemic after emerging in 2005. Methods: We sequenced the genomes of 133 clinical isolates recovered from 24 tertiary care hospitals located in 10 cities throughout Colombia, between 2002 (before the emergence of KPC-Kpn) and 2014. Phylogenetic reconstructions and evolutionary mapping were performed to determine temporal and genetic associations between the isolates. Results: Our results indicate that the start of the epidemic was driven by horizontal dissemination of mobile genetic elements carrying blaKPC-2, followed by the introduction and subsequent spread of clonal group 258 (CG258) isolates containing blaKPC-3. Conclusions: The combination of 2 evolutionary mechanisms of KPC-Kpn within a challenged health system of a developing country created the "perfect storm" for sustained endemicity of these multidrug-resistant organisms in Colombia.

Contribution of spores to the ability of Clostridium difficile to adhere to surfaces.

Clostridium difficile is the commonest cause of hospital-acquired infection in the United Kingdom. We characterized the abilities of 21 clinical isolates to form spores; to adhere to inorganic and organic surfaces, including stainless steel and human adenocarcinoma cells; and to germinate. The composition of culture media had a significant effect on spore formation, as significantly more spores were produced in brain heart infusion broth (Student's t test; P = 0.018). The spore surface relative hydrophobicity (RH) varied markedly (14 to 77%) and was correlated with the ability to adhere to stainless steel. We observed no correlation between the ribotype and the ability to adhere to steel. When the binding of hydrophobic (DS1813; ribotype 027; RH, 77%) and hydrophilic (DS1748; ribotype 002; RH, 14%) spores to human gut epithelial cells at different stages of cell development was examined, DS1813 spores adhered more strongly, suggesting the presence of surface properties that aid attachment to human cells. Electron microscopy studies revealed the presence of an exosporium surrounding DS1813 spores that was absent from spores of DS1748. Finally, the ability of spores to germinate was found to be strain and medium dependent. While the significance of these findings to the disease process has yet to be determined, this study has highlighted the importance of analyzing multiple isolates when attempting to characterize the behavior of a bacterial species.

Effects of Genic Base Composition on Growth Rate in G+C-rich Genomes.

The source and significance of the wide variation in the genomic base composition of bacteria have been a matter of continued debate. Although the variation was originally attributed to a strictly neutral process, i.e., species-specific differences in mutational patterns, recent genomic comparisons have shown that bacteria with G+C-rich genomes experience a mutational bias toward A+T. This difference between the mutational input to a genome and its overall base composition suggests the action of natural selection. Here, we examine if selection acts on G+C contents in Caulobacter crescentus and Pseudomonas aeruginosa, which both have very G+C-rich genomes, by testing whether the expression of gene variants that differ only in their base compositions at synonymous sites affects cellular growth rates. In C. crescentus, expression of the more A+T-rich gene variants decelerated growth, indicating that selection on genic base composition is, in part, responsible for the high G+C content of this genome. In contrast, no comparable effect was observed in P. aeruginosa, which has similarly high genome G+C contents. Selection for increased genic G+C-contents in C. crescentus acts independently of the species-specific codon usage pattern and represents an additional selective force operating in bacterial genomes.