Population structure and characterization of viridans group streptococci (VGS) including Streptococcus pneumoniae isolated from adult patients with cystic fibrosis (CF)

A study was undertaken to examine the population structure of viridans group streptococci (VGS) in the sputum of adult patients with cystic fibrosis (CF). Freshly expectorated sputa (n=58) from 45 adult CF patients were examined by selective conventional culture on Mitis-Salivarius agar and yielded 190 isolates of VGS. Sequence analyses of the rpnB and 16-23S rRNA ITS genes identified these isolates to belong to 12 species of VGS and included S. anginosus, S. australis, S. cristatus, S. gordonii, S. infantis, S. mitis, S. mutans, S. oralis, S. parasanguinis, S. pneumoniae, S. salivarius and S. sanguinis. The most frequently VGS organism isolated was S. salivarius (47/190; 24.7%), followed by S. mitts (36/190; 19%), S. sanguinis (25/190; 13.2%), S. oralis (20/190; 11.0%), S. pneumoniae (19/190; 10.0%), S. parasanguinis (16/190; 8.4%), S. infantis (11/190; 5.8%), S. gordonii (7/190; 3.7%), S. anginosus (4/190; 2.1%), S. cristatus (2/190; 1.1%), S. australis (1/190; 0.5%), S. mutans (1/190; 0.5%) and S. agalactiae (1/190; 0.5%). All, but four, patients harboured at least one VGS species, which ranged from one to five streptococcal species, with a mean of 2.85 species per patient. There was no clonality at the subspecies level employing ERIC RAPD PCR. Antibiotic susceptibility was determined by Minimum Inhibitory Concentration (MIC) testing against penicillin, erythromycin and ciprofloxacin. Overall, resistance to penicillin with all VGS was 73/190 (38.4%) and 167/190 (87.9%) for erythromycin. With regard to ciprofloxacin, 27/190 (14.2%) were fully resistant, whilst a further 21/190 (11.1%) showed intermediate resistance, which equated to approximately three quarters (74.7%) of isolates being fully sensitive to this agent. In addition, as a comparator control population, we examined antibiotic susceptibility, as above, in a non-CF population comprising 12 individuals (50 VGS isolates), who were not receiving chronic antibiotics. In comparison, 8% and 38% of VGS isolates from non-CF individuals were resistant by disk susceptibility testing to penicillin and erythromycin, respectively. None of the non-CF VGS organisms were resistant to ciprofloxacin, but 42% showed intermediate resistance. (C) 2010 European Cystic Fibrosis Society. Published by Elsevier B.V. All rights reserved.

An integrated multi-sensor data fusion algorithm and autopilot iImplementation in an uninhabited surface craft

Unmanned surface vehicles (USVs) are able to accomplish difficult and challenging tasks both in civilian and defence sectors without endangering human lives. Their ability to work round the clock makes them well-suited for matters that demand immediate attention. These issues include but not limited to mines countermeasures, measuring the extent of an oil spill and locating the source of a chemical discharge. A number of USV programmes have emerged in the last decade for a variety of aforementioned purposes. Springer USV is one such research project highlighted in this paper. The intention herein is to report results emanating from data acquired from experiments on the Springer vessel whilst testing its advanced navigation, guidance and control (NGC) subsystems. The algorithms developed for these systems are based on soft-computing methodologies. A novel form of data fusion navigation algorithm has been developed and integrated with a modified optimal controller. Experimental results are presented and analysed for various scenarios including single and multiple waypoints tracking and fixed and time-varying reference bearings. It is demonstrated that the proposed NGC system provides promising results despite the presence of modelling uncertainty and external disturbances.