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.

Growth Inhibitory Activity of Extracted Material and Isolated Compounds from the Fruits of Kigelia pinnata

A study of the components of the fruits of Kigelia pinnata was undertaken to identify compounds with potential growth inhibitory activity against human melanoma cells, since extracts from the fruits of this plant have been described in traditional medicine to have application in the treatment of skin cancer and other skin ailments. A bioactivity-guided fractionation process yielded a number of crude fractions, which demonstrated cytotoxicity in vitro against human melanoma cells. Compounds isolated and identified included the isocoumarins, demethylkigelin (1) and kigelin 2), fatty acids, oleic (3) and heneicosanoic acids (4), the furonaphthoquinone, 2-(1-hydroxyethyl)-naphtho[2,3-b]furan-4,9-dione (5), and ferulic acid (6). A number of structurally related synthetic compounds were also tested using the MTT assay. The most potent series of these compounds, the furonaphthoquinones, also demonstrated a cytotoxic effect in two human breast cancer cell lines tested.