Clostridium difficile infection (CDI) is one of the most frequent causes of healthcare-associated infections, and its rates are also increasing in the community. The management of CDI has become a major challenge, given growing rates of recurrences and failures with standard antibiotic therapy. Mounting evidence suggests that fecal microbiota transplantation (FMT) may be effective; however, as there is a paucity of data with regard to repeat FMT for primary non-response to this treatment, this study examined the outcome of multiple FMTs for recurrent CDI. Case records were reviewed for 94 patients who underwent FMT via retention enema for recurrent or refractory CDI during the period 2008-2012. Demographic information, treatment data, and clinical resolution rates were examined for single FMT and cumulative resolution was assessed for multiple FMTs in the context of ongoing symptoms. The cumulative clinical resolution following four or more FMTs was 86%. When antibiotic therapy was used between FMTs, the clinical resolution rate increased to 92%. There were no reported adverse events and no patients who were cured with FMT had further episodes of CDI at 6-24 months follow-up. Multiple FMTs administered through enemas is an effective, safe, and simple therapy for the management of recurrent or refractory CDI.

For systems containing large numbers of ions, calculations using Density Functional Theory (DFT) are often impractical because of the amount of time needed to perform the computations. In this paper, we show that weighted-average Madelung constants of MgO nanotubes correlate in an essentially perfectly linear way with cohesive energies determined by DFT. We discuss this correlation in terms of the relationship between lattice energies and cohesive energies. Through this linear correlation, Madelung constants are used to predict cohesive energies and average ion charges of nanostructures containing up to 3940 ions. Cohesive energies of MgO nanotubes are shown to converge to a value lower than those of bulk MgO. Using the slopes of the DFT versus Madelung constant plots, the average charges on the ions in the nanotubes are determined. For nanotubes containing the same number of ions, the relative stability of longer tubes versus disc-like structures is discussed.

In this paper, the bonding, relative stabilities, and local ionic charges occurring in sodium chloride nanotubes are discussed. A new methodology is introduced which employs a linear relationship between nanotube cohesive energies determined via density functional theory (DFT) and weighted-average Madelung constants (MC(wa)). The slope of the linear plots reveals ionic charges and gives insights into ionic and other contributions to the bonding. Comparisons between ionic and cohesive bonding energies indicate that, as the nanotubes become longer, ionic bonding provides the principal contribution to the increased stabilization. Furthermore, comparisons between the total cohesive and electrostatic energies are used to calculate the percent ionicities. The nanotubes discussed in this paper show that percent ionicity ranges from 47 to 58%. Increasing lengths and decreasing widths of the tubes favor higher ionic character. A linear relationship linking the average ionic coordination number and MC(wa) is also presented for the first time.