Untangling above- and belowground mycorrhizal fungal networks in tropical orchids.

Orchids typically depend on fungi for establishment from seeds, forming mycorrhizal associations with basidiomycete fungal partners in the polyphyletic group rhizoctonia from early stages of germination, sometimes with very high specificity. This has raised important questions about the roles of plant and fungal phylogenetics, and their habitat preferences, in controlling which fungi associate with which plants. In this issue of Molecular Ecology, Martos et al. (2012) report the largest network analysis to date for orchids and their mycorrhizal fungi, sampling a total of over 450 plants from nearly half the 150 tropical orchid species on Reunion Island, encompassing its main terrestrial and epiphytic orchid genera. The authors found a total of 95 operational taxonomic units of mycorrhizal fungi and investigated the architecture and nestedness of their bipartite networks with 73 orchid species. The most striking finding was a major ecological barrier between above- and belowground mycorrhizal fungal networks, despite both epiphytic and terrestrial orchids often associating with closely related taxa across all three major lineages of rhizoctonia fungi. The fungal partnerships of the epiphytes and terrestrial species involved a diversity of fungal taxa in a modular network architecture, with only about one in ten mycorrhizal fungi partnering orchids in both groups. In contrast, plant and fungal phylogenetics had weak or no effects on the network. This highlights the power of recently developed ecological network analyses to give new insights into controls on plant-fungal symbioses and raises exciting new hypotheses about the differences in properties and functioning of mycorrhiza in epiphytic and terrestrial orchids.

The effect of a large Legionnaires' disease outbreak in Southwest Edinburgh on acute and critical care services.

OBJECTIVE: The largest outbreak of Legionnaires Disease (LD) in the UK for a decade occurred in Edinburgh in June 2012. We describe the clinical and public health management of the outbreak. SETTING: Three acute hospitals covering an urban area of ~480,000. METHODS: Data were collected on confirmed and suspected cases and minutes of the Incident Management Team meetings were reviewed to identify key actions. RESULTS: Over 1600 urine samples and over 600 sputum samples were tested during the outbreak. 61 patients with pneumonia tested positive for Legionella pneumophila serogroup 1 by urinary antigen detection, culture, respiratory PCR or serology. A further 23 patients with pneumonia were treated as suspected cases on clinical and epidemiological grounds but had no microbiological diagnosis. 36% of confirmed and probable cases required critical care admission. Mean ICU length of stay was 11.3 (±7.6) days and mean hospital length of stay for those who were admitted to ICU was 23.0 (±17.2) days. For all hospitalized patients the mean length of stay was 15.7 (±14) days. In total there were four deaths associated with this outbreak giving an overall case fatality of 6.5%. Hospital and critical care mortality was 6.1% and 9.1%, respectively. CONCLUSION: A significant proportion of patients required prolonged multiple organ support or complex ventilation. Case fatality compared favourably to other recent outbreaks in Europe. Access to rapid diagnostic tests and prompt antibiotic therapy may have mitigated the impact of pre-existing poor health among those affected.

Calcification of the intrarenal branches of the renal arteries.

Mild to extensive calcification of the intrarenal branches of the renal arteries seen in 13 patients over a period of 12 months is described. This type of renal vascular calcification appeared to be associated with generalised atherosclerosis in patients of advancing age. The association of diabetes mellitus and intrarenal arterial calcification could not be supported by the cases presented here.

Hysterosalpingography using a Foley catheter.

The authors describe a simple method of hysterosalpingography using a Foley catheter to inject contrast media. The technique allows the patient to assume a more comfortable position during the study. The radiologist can perform the examination without the need of a second physician to assist during spot filming and with no chance of metal artifacts obscuring anatomy.