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To evaluate whether different deoxyribonucleic acid (DNA) extraction procedures can affect estimates of bacterial community composition, based on the 16S ribosomal ribonucleic acid gene denaturing gradient gel electrophoresis (DGGE) profiles, we compared four in situ lysis procedures using three soils and one marine sediment. Analysis of DGGE profiles, generated by polymerase chain reaction of purified DNA extracts, demonstrated that the choice of DNA extraction method significantly influenced the bacterial community profiles generated. This was reflected both in the number of bands or ribotypes detected from each sample and in subsequent principle coordinate analysis and unweighted-pair group method using arithmetic average analyses. The methods also differed significantly in their robustness, i.e. reproducibility across multiple analyses. Two methods, both based on bead beating, were demonstrated to be suitable for comparative studies of a range of soil and sediment types.

The microbial ecology of a range of anaerobic biological assemblages (granular sludge) from full- and laboratory-scale wastewater treatment bioreactors, and of crop-growing and peat soils, was determined using a variety of 16S rRNA gene-based techniques, including clone library, terminal restriction fragment length polymorphism (TRFLP) and denaturing gradient gel electrophoresis (DGGE) analyses. Fluorescent in situ hybridization (FISH) using 16S rRNA gene-targeted probes was employed to complete a "full-cycle rRNA approach" with selected biomass. Genetic fingerprinting (TRFLP and DGGE) was effectively used to elucidate community structure-crop relationships, and to detect and monitor trends in bioreactor sludge and specific enrichment cultures of peat soil. Greater diversity was resolved within bacterial than within archaeal communities, and unexpected reservoirs of uncultured Crenarchaeota were detected in sludge granules. Advanced radiotracer incubations and micro-beta imaging were employed in conjunction with FISH to elucidate the eco-functionalism of these organisms. Crenarchaeota clusters were identified in close associated with methanogenic Archaea and both were localised with acetate uptake in biofilm structure.

The dinophycean genus Heterocapsa is of considerable interest as it contains a number of bloom-forming and/or harmful species. Fine structure of organic body scales is regarded as the most important morphological feature for species determination but currently is unknown for the species H. minima described by Pomroy 25 years ago. Availability of a culture of H. minima collected in the south-west of Ireland allowed us to provide important information for this species, including cell size, cell organelle location, thecal plate pattern, body scale fine structure and molecular phylogeny. Light microscopy revealed the presence of one reticulate chloroplast, an elongated centrally located nucleus, and the presence of one pyrenoid surrounded by a starch sheath. Scanning electron microscopy (SEM) of the thecal plate pattern indicated that Pomroy erroneously designated the narrow first cingular plate as a sulcal plate. In addition, SEM revealed as yet unreported details of the apical pore complex and uncommon ornamentations of hypothecal plates. Organic body scales of H. minima were about 400 nm in size, roundish, with a small central hole and one central, six peripheral and three radiating spines. They differ from other body scales described within this genus allowing for positive identification of H. minima. Heterocapsa minima shares gross cell morphological features (hyposome smaller than episome, elongated nucleus in the middle of the cell, one pyrenoid located in the episome on its left side) with H. arctica (both subspecies H. arctica subsp. arctica and H. arctica subsp. frigida), H. lanceolata and H. rotundata. These relationships are reflected in the phylogenetic trees based on LSU and ITS rDNA sequence data, which identified H. arctica (both subspecies), H. rotundata and H. lanceolata as close relatives of H. minima.

BackgroundThe prevalence of urinary tract infections (UTIs) caused by extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is increasing and the therapeutic options are limited, especially in primary care. Recent indications have suggested pivmecillinam to be a suitable option. This pilot study aimed to assess the viability of pivmecillinam as a therapeutic option in a Dublin cohort of mixed community and healthcare origin.MethodsA prospective measurement of mean and fractional inhibitory concentrations of antibiotic use in 95 patients diagnosed with UTI caused by ESBL-producing Enterobacteriaceae was carried out. 36 % patients were from general practice, 40 % were admitted to hospital within south Dublin, and 25 % samples arose from nursing homes. EUCAST breakpoints were used to determine if an isolate was sensitive or resistant to antibiotic agents.ResultsSixty-nine percent of patients (N = 66) with urinary ESBL isolates were female. The mean age of females was 66 years compared with a mean age of 74 years for males. Thirty-six percent of isolates originated from primary care, hospital inpatients (26 %), and nursing homes (24 %). The vast majority of ESBL isolates were E. coli (80 %). The E tests for mecillinam and co-amoxiclav had concentration ranges from 0.16 mg/L up to 256 mg/L. The mean inhibitory concentration (MIC) of mecillinam ranged from 0.25 to 256 mg/L, while co-amoxiclav MICs ranged from 6 to 256 mg/L. The percentage of isolates resistant to mecillinam and co-amoxiclav was found to be 5.26 and 94.74 % respectively.ConclusionsThis is the first study exploring the use of pivmecillinam in an Irish cohort and has demonstrated that its use in conjunction with or without co-amoxiclav is an appropriate and useful treatment for urinary tract infections caused by ESBL-producing organisms.