Influenza Virus in Human Exhaled Breath: An Observational Study

Background: Recent studies suggest that humans exhale fine particles during tidal breathing but little is known of their composition, particularly during infection. Methodology/Principal Findings: We conducted a study of influenza infected patients to characterize influenza virus and particle concentrations in their exhaled breath. Patients presenting with influenza-like-illness, confirmed influenza A or B virus by rapid test, and onset within 3 days were recruited at three clinics in Hong Kong, China. We collected exhaled breath from each subject onto Teflon filters and measured exhaled particle concentrations using an optical particle counter. Filters were analyzed for influenza A and B viruses by quantitative polymerase chain reaction (qPCR). Twelve out of thirteen rapid test positive patients provided exhaled breath filter samples (7 subjects infected with influenza B virus and 5 subjects infected with influenza A virus). We detected influenza virus RNA in the exhaled breath of 4 (33%) subjects-three (60%) of the five patients infected with influenza A virus and one (14%) of the seven infected with influenza B virus. Exhaled influenza virus RNA generation rates ranged from <3.2 to 20 influenza virus RNA particles per minute. Over 87% of particles exhaled were under 1 μm in diameter. Conclusions: These findings regarding influenza virus RNA suggest that influenza virus may be contained in fine particles generated during tidal breathing, and add to the body of literature suggesting that fine particle aerosols may play a role in influenza transmission. © 2008 Fabian et al.published_or_final_versio

Identification of a General O-linked Protein Glycosylation System in Acinetobacter baumannii and Its Role in Virulence and Biofilm Formation

Acinetobacter baumannii is an emerging cause of nosocomial infections. The isolation of strains resistant to multiple antibiotics is increasing at alarming rates. Although A. baumannii is considered as one of the more threatening “superbugs” for our healthcare system, little is known about the factors contributing to its pathogenesis. In this work we show that A. baumannii ATCC 17978 possesses an O-glycosylation system responsible for the glycosylation of multiple proteins. 2D-DIGE and mass spectrometry methods identified seven A. baumannii glycoproteins, of yet unknown function. The glycan structure was determined using a combination of MS and NMR techniques and consists of a branched pentasaccharide containing N-acetylgalactosamine, glucose, galactose, N-acetylglucosamine, and a derivative of glucuronic acid. A glycosylation deficient strain was generated by homologous recombination. This strain did not show any growth defects, but exhibited a severely diminished capacity to generate biofilms. Disruption of the glycosylation machinery also resulted in reduced virulence in two infection models, the amoebae Dictyostelium discoideum and the larvae of the insect Galleria mellonella, and reduced in vivo fitness in a mouse model of peritoneal sepsis. Despite A. baumannii genome plasticity, the O-glycosylation machinery appears to be present in all clinical isolates tested as well as in all of the genomes sequenced. This suggests the existence of a strong evolutionary pressure to retain this system. These results together indicate that O-glycosylation in A. baumannii is required for full virulence and therefore represents a novel target for the development of new antibiotics

Genotoxicity and antigenotoxicity assessment of shiitake (Lentinula edodes (Berkeley) Pegler) using the Comet assay

The mushroom shiitake (Lentinula edodes (Berkeley) Pegler) is been widely consumed in many countries, including Brazil, because of its pleasant flavor and reports of its therapeutic properties, although there is little available information on the genotoxicity and/or antigenotoxicity of this mushroom. We used the Comet assay and HEp-2 cells to evaluate the in vitro genotoxic and antigenotoxic activity of aqueous extracts of shiitake prepared in three different concentrations (0.5, 1.0 and 1.5 mg/mL) and three different temperatures (4, 22 and 60 °C), using methyl methanesulfonate (MMS) as a positive control and untreated cells as a negative control. Two concentrations (1.0 and 1.5 mg/mL) of extract prepared at 4 °C and all of the concentrations prepared at 22 ± 2 and 60 °C showed moderate genotoxic activity. To test the protective effect of the three concentrations of the extracts against the genotoxicity induced by methyl methanesulfonate, three protocols were used: pre-treatment, simultaneous-treatment and post-treatment. Treatments were repeated for all combinations of preparation temperature and concentration. Two extracts (22 ± 2 °C 1.0 mg/mL (simultaneous-treatment) and 4 °C 0.5 mg/mL (post-treatment)) showed antigenotoxic activity