Abiotic stress has a growing impact on plant growth and agricultural activity worldwide. Specific plant growth promoting rhizobacteria have been reported to stimulate growth and tolerance to abiotic stress in plants, and molecular mechanisms like phytohormone synthesis and 1-aminocyclopropane-1-carboxylate deamination are usual candidates proposed to mediate these bacterial effects. Paraburkholderia phytofirmans PsJN is able to promote growth of several plant hosts, and improve their tolerance to chilling, drought and salinity. This work investigated bacterial determinants involved in PsJN stimulation of growth and salinity tolerance in Arabidopsis thaliana, showing bacteria enable plants to survive long-term salinity treatment, accumulating less sodium within leaf tissues relative to non-inoculated controls. Inactivation of specific bacterial genes encoding ACC deaminase, auxin catabolism, N-acyl-homoserine-lactone production, and flagellin synthesis showed these functions have little influence on bacterial induction of salinity tolerance. Volatile organic compound emission from strain PsJN was shown to reproduce the effects of direct bacterial inoculation of roots, increasing plant growth rate and tolerance to salinity evaluated both in vitro and in soil. Furthermore, early exposure to VOCs from P. phytofirmans was sufficient to stimulate long-term effects observed in Arabidopsis growth in the presence and absence of salinity. Organic compounds were analyzed in the headspace of PsJN cultures, showing production of 2-undecanone, 7-hexanol, 3-methylbutanol and dimethyl disulfide. Exposure of A. thaliana to different quantities of these molecules showed that they are able to influence growth in a wide range of added amounts. Exposure to a blend of the first three compounds was found to mimic the effects of PsJN on both general growth promotion and salinity tolerance. To our knowledge, this is the first report on volatile compound-mediated induction of plant abiotic stress tolerance by a Paraburkholderia species.

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The significant increase in the prevalence of resistance to clindamycin and miocamycin, and the prevalence of resistance to telithromycin reached in a short period of time from the introduction of its use, underscore the need for continuous surveillance of antimicrobial resistance in S. pyogenes in Spain.

The Granada agar plate (GAP; Biomedics SL, Madrid, Spain) was evaluated for the detection of group B streptococci (GBS) in urine specimens from pregnant women submitted for testing for asymptomatic bacteriuria and was compared with blood agar (BA [Columbia agar with 5% sheep blood]; bioMérieux, Marcy l'Etoile, France). The GAP detected 103 out of 105 GBS, whereas BA detected only 50. Use of the GAP could be a good method for the detection of GBS in urine specimens from pregnant women. Group B streptococcus (GBS [Streptococcus agalactiae])is a relevant cause of neonatal infection worldwide. The research on this microorganism in women at the end of pregnancy is based on the fact that women with vaginal and/or rectal colonization have a higher probability of severe perinatal infection (7).In 2002, the Centers for Disease Control and Prevention (CDC) issued some guidelines for the prevention of perinatal GBS infection. Those guidelines state that the mere presence of GBS in urine, irrespective of its concentration, is a reliable marker of heavy genital colonization (8, 11) with increased risk of premature birth and other obstetric problems (3). Therefore, women with any urine concentration of GBS during pregnancy should receive chemoprophylaxis at labor. In these cases, vaginal or rectal screening in weeks 35 to 37 is not necessary (11).A urine specimen culture is currently recommended for all pregnant women at the end of the first term or beginning of the second term to detect possible asymptomatic bacteriuria (2, 6). The urine specimen is cultured in a nonselective medium, usually blood agar (BA).The objective of our study was to evaluate the Granada agar plate (GAP) for the detection of GBS in urine specimens of pregnant women by comparing it with BA. Urine specimens taken routinely to detect asymptomatic bacteriuria were investigated.From January to August 2003, 834 urine specimens from pregnant women in the Móstoles Hospital area (Madrid, Spain) were received for asymptomatic bacteriuria testing. The urine specimens were plated onto two different media: BA medium (Columbia agar with 5% sheep blood; bioMérieux, Marcy l'Etoile, France) and GAP medium (Biomedics SL, Madrid, Spain). The BA plates were incubated at 37°C for 24 h. By protocol, the urine samples used for detection of asymptomatic bacteriuria in pregnant women are cultured in BA and MacConkey agar in our laboratory. As the main objective of our study is to compare the advantages of the GAP to those of BA by using the same sample to determine the existence of asymptomatic bacteriuria and the presence of GBS, we did not utilize an enrichment medium. Assuming that the use of a broth would yield higher rates of isolation of GBS in urine samples, the GBS carriers would be identified by examination of the vaginal and rectal samples taken in the last days of pregnancy, according to the protocol of the CDC (11).Beta-hemolytic, catalase-negative colonies grown on BA that showed characteristics consistent with GBS were agglutinated with latex particles coated wi...