Predominant pathogen competition and core microbiota divergence in chronic airway infection

© 2015 International Society for Microbial Ecology All rights reserved. Chronic bacterial lung infections associated with non-cystic fibrosis bronchiectasis represent a substantial and growing health-care burden. Where Pseudomonas aeruginosa is the numerically dominant species within these infections, prognosis is significantly worse. However, in many individuals, Haemophilus influenzae predominates, a scenario associated with less severe disease. The mechanisms that determine which pathogen is most abundant are not known. We hypothesised that the distribution of H. influenzae and P. aeruginosa would be consistent with strong interspecific competition effects. Further, we hypothesised that where P. aeruginosa is predominant, it is associated with a distinct 'accessory microbiota' that reflects a significant interaction between this pathogen and the wider bacterial community. To test these hypotheses, we analysed 16S rRNA gene pyrosequencing data generated previously from 60 adult bronchiectasis patients, whose airway microbiota was dominated by either P. aeruginosa or H. influenzae. The relative abundances of the two dominant species in their respective groups were not significantly different, and when present in the opposite pathogen group the two species were found to be in very low abundance, if at all. These findings are consistent with strong competition effects, moving towards competitive exclusion. Ordination analysis indicated that the distribution of the core microbiota associated with each pathogen, readjusted after removal of the dominant species, was significantly divergent (analysis of similarity (ANOSIM), R=0.07, P=0.019). Taken together, these findings suggest that both interspecific competition and also direct and/or indirect interactions between the predominant species and the wider bacterial community may contribute to the predominance of P. aeruginosa in a subset of bronchiectasis lung infections

Analysis of gamma emitting radionuclides (terrestrial and anthropogenic) in soil samples from Kilis province in south Anatolia, Turkey

In recent years, there has been great concern about analysis of radionuclide content in environmental samples (soil, water, etc.) in many countries. The aim of the present study is to analyze the activity concentrations of terrestrial (226Ra, 232Th and 40K) and anthropogenic (137Cs) radionuclides in surface soil samples collected from different locations in and around Kilis province using the high-resolution gamma spectrometer with HPGe detector and evaluate external ionizing radiation exposure in outdoor air. The mean values of the activity concentrations of 226Ra, 232Th, 40K and 137Cs in the soil samples were analyzed as 16.1, 15.0, 206.0 and 9.5 Bq kg-1, respectively. Evaluated values of absorbed gamma dose rate in outdoor air and the corresponding external annual effective dose varied from 5 to 75 nGy h-1 with a mean value of 25 nGy h-1 and 6-92 µSv with a mean value of 31 µSv, respectively. These mean values were found to be within acceptable limits. © 2013 Elsevier Ltd. All rights reserved.

Chronic pelvic abscedation after completion proctectomy in a rectal stump insufficiency; treatment with gracilis muscle flap following vacuum assisted closure therapy

Presacral abscess formation due to rectal stump insufficiency following Hartmann procedure is very rare complication. If the abscess cavity is large, it might delay the reversal of the stoma and will probably result in a devastating future functioning of the neorectum. Moreover, very invasive treatments will be required in order to prevent severe septic complications. We present the case of a 58-year-old man with a past history of Hartmann procedure for a low rectal carcinoma who presented with rectal stump insufficiency and a large presacral abscess. Following extensive debridement and rectal stump resection, a vacuum-assisted closure (VAC) system was applied to the large abscess cavity to facilitate gracilis muscle flap reconstruction and to optimize wound healing. The satisfactory results showed in the present report led us to favor a combination of VAC therapy and a gracilis muscle flap in intrapelvic and perineal reconstruction in the case of large defects associated with high risks of septic complications. © 2013 The Korean Society of Coloproctology