The International Symposium on Fungal Stress - ISFUS

Fungi play central roles in many biological processes, influencing soil fertility, decomposition, cycling of minerals, and organic matter, plant health, and nutrition. They produce a wide spectrum of molecules, which are exploited in a range of industrial processes to manufacture foods, food preservatives, flavoring agents, and other useful biological products. Fungi can also be used as biological control agents of microbial pathogens, nematodes or insect pests, and affect plant growth, stress tolerance, and nutrient acquisition. Successful exploitation of fungi requires better understanding of the mechanisms that fungi use to cope with stress as well as the way in which they mediate stress tolerance in other organisms. It is against this backdrop that a scientific meeting on fungal stress was held in São José dos Campos, Brazil, in October 2014. The meeting, hosted by Drauzio E. N. Rangel and Alene E. Alder-Rangel, and supported by the São Paulo Research Foundation (FAPESP), brought together more than 30 young, mid-career, and highly accomplished scientists from ten different countries. Here we summarize the highlights of the meeting.

An audit of antimicrobial treatment of lower respiratory and urinary tract infections in a hospital setting

Objectives: To audit the quality of treatment of lower respiratory tract infections (LRTIs) and urinary tract infections (UTIs) and to identify targets for antibiotic stewardship. Methods: The audit involved collecting data on admitted patients, who were diagnosed with LRTIs or UTIs and subsequently received antibiotic treatment (January 2009-April 2009). Key findings: The percentage adherence rate for hospital antibiotic policy was 68.6% (24/35). Documentation of the CURB-65 score was found in 80% (16/20) of the patients' clinical notes, for which 46.2% (6/13) of patients were treated according to their CURB- 65 score. The percentages of delayed and missed doses for all antibiotics were 21.7% (254/1171) and 8.6% (101/1171), respectively. The percentage of patients switched from intravenous to oral antibiotics in accordance with the policy was 58.5% (31/53). The mean length of stay for patients switched in line with the guidelines was 6.9 days (range: 2-18 days) compared with 13.2 days (range: 4-28 days) for patients treated with intravenous antibiotics >24 h after the intravenous to oral switch criteria were fulfilled; this equates to on average an extra 6.3 days of hospitalisation (p=0.01). Conclusions: The study identified a number of targets for quality improvement including adherence to antibiotic policy, documentation of the CURB-65 score in patients' notes and treating patients accordingly, addressing the issue of missed and delayed doses, and maintaining adherence to the hospital intravenous-to-oral antibiotic switch policy. The findings suggest that the quality of antibiotic prescribing could be improved by measuring and addressing such performance indicators.

Genetic diversity of root-associated fungal endophytes from Calluna vulgaris at contrasting field sites

A total of 107 putative ericoid mycorrhizal endophytes were isolated from hair roots of Calluna vulgaris from two abandoned arsenic/copper mine sites and a natural heathland site in southwest England. The endophytes were initially grouped as 14 RFLP types, based on the results of ITS-RFLP analysis using the restriction endonucleases Hinf I, Rsa I and Hae III. ITS sequences were obtained for representative isolates from each RFLP type and compared phylogenetically with sequences for known ericoid mycorrhizal endophytes and selected ascomycetes. The majority of endophyte isolates (62-92%) from each site were identified as Hymenoscyphus ericae, but a number of other less common mycorrhizal RFLP types were also identified, all of which appear to have strong affinities with the order Leotiales. None of the less common RFLP types was isolated from C. vulgaris at more than one field site. Neighbour-joining analysis indicated similarities between the endophytes from C. vulgaris and mycorrhizal endophytes isolated from other Ericaceae and Epacridaceae hosts in North America and Australia.

Ultrashort self-assembling peptidomimetic nanomaterials target resistant pathogenic infections

The impending and increasing threat of antimicrobial resistance has led to a greater focus into developing alternative therapies as substitutes for traditional antibiotics for the treatment of multi-drug resistant infections.1 Our group has developed a library of short, cost-effective, diphenylalanine-based peptides (X1-FF-X2) which selective eradicate (viability reduced >90% in 24 hours) the most resistant biofilm forms of a range of Gram-positive and negative pathogens including: methicillin resistant and sensitive Staphyloccoccus aureus and Staphyloccoccus epidermidis; Pseudomonas aeruginosa, Proteus mirabilis and Escherichia coli. They demonstrate a reduced cell cytotoxic profile (NCTC929 murine fibroblast) and limited haemolysis.2 Our molecules have the ability respond to subtle changes in pH, associated with bacterial infection, self-assembling to form β-sheet secondary structures and supramolecular hydrogels at low concentrations (~0.5%w/v). Conjugation of variety of aromatic-based drugs at the X1 position, including non-steroidal anti-inflammatories (NSAIDs), confer further pharmacological properties to the peptide motif enhancing their therapeutic potential. In vivo studies using waxworms (Galleria mellonella) provide promising preliminary results demonstrating the low toxicity and high antimicrobial activity of these low molecular weight gelators in animal models. This work shows biofunctional peptide-based nanomaterials hold great promise for future translation to patients as antimicrobial drug delivery and biomaterial platforms.3 [1] G. Laverty, S.P. Gorman and B.F. Gilmore. Int.J.Mol.Sci. 2011, 12, 6566-6596. [2] G. Laverty, A.P. McCloskey, B.F. Gilmore, D.S. Jones, J Zhou, B Xu. Biomacromolecules. 2014, 15, 9, 3429-3439. [3] A.P. McCloskey, B.F. Gilmore and G.Laverty. Pathogens. 2014, 3, 791-821.

Biocontrol agents promote growth of potato pathogens, depending on environmental conditions

There is a pressing need to understand and optimize biological control so as to avoid over-reliance on the synthetic chemical pesticides that can damage environmental and human health. This study focused on interactions between a novel biocontrol-strain, Bacillus sp. JC12GB43, and potato-pathogenic Phytophthora and Fusarium species. In assays carried out in vitro and on the potato tuber, the bacterium was capable of near-complete inhibition of pathogens. This Bacillus was sufficiently xerotolerant (water activity limit for growth = 0.928) to out-perform Phytophthora infestans (~0.960) and challenge Fusarium coeruleum (~0.847) and Fusarium sambucinum (~0.860) towards the lower limits of their growth windows. Under some conditions, however, strain JC12GB43 stimulated proliferation of the pathogens: for instance, Fusarium coeruleum growth-rate was increased under chaotropic conditions in vitro (132 mM urea) by >100% and on tubers (2-M glycerol) by up to 570%. Culture-based assays involving macromolecule-stabilizing (kosmotropic) compatible solutes provided proof-of-principle that the Bacillus may provide kosmotropic metabolites to the plant pathogen under conditions that destabilize macromolecular systems of the fungal cell. Whilst unprecedented, this finding is consistent with earlier reports that fungi can utilize metabolites derived from bacterial cells. Unless the antimicrobial activities of candidate biocontrol strains are assayed over a full range of field-relevant parameters, biocontrol agents may promote plant pathogen infections and thereby reduce crop yields. These findings indicate that biocontrol activity, therefore, ought to be regarded as a mode-of-behaviour (dependent on prevailing conditions) rather than an inherent property of a bacterial strain.

Arbuscular mycorrhizal fungal hyphae reduce soil erosion by surface water flow in a greenhouse experiment

The role of arbuscular mycorrhizal fungi (AMF) in resisting surface flow soil erosion has never been tested experimentally. We set up a full factorial greenhouse experiment using Achillea millefolium with treatments consisting of addition of AMF inoculum and non-microbial filtrate, non-AMF inoculum and microbial filtrate, AMF inoculum and microbial filtrate, and non-AMF inoculum and non-microbial filtrate (control) which were subjected to a constant shear stress in the form of surface water flow to quantify the soil detachment rate through time. We found that soil loss can be explained by the combined effect of roots and AMF extraradical hyphae and we could disentangle the unique effect of AMF hyphal length, which significantly reduced soil loss, highlighting their potential importance in riparian systems.

Continuing the fight in reducing the risk of surgical site infections in the perioperative environment

Assessing risk has become part of the process of supporting patients andmaintaining safety in the healthcare setting. The risk of healthcare associatedinfections (HCAIs) has long been well documented and surgical site infection (SSI)is recognised as one of the most prevalent (Tanner & Khan 2008, Wilson 2013a).

Potential strategies for the eradication of multi-drug resistant Gram-negative bacterial infections

Antimicrobial resistance is one of the leading threats to society. The increasing burden of multidrug-resistant Gram-negative infection is particularly concerning as such bacteria are demonstrating resistance to nearly all currently licensed therapies. Various strategies have been hypothesized to treat multidrug-resistant Gram-negative infections including: targeting the Gram-negative outer membrane; neutralization of lipopolysaccharide; inhibition of bacterial efflux pumps and prevention of protein folding. Silver and silver nanoparticles, fusogenic liposomes and nanotubes are potential strategies for extending the activity of licensed, Gram-positive selective, antibiotics to Gram-negatives. This may serve as a strategy to fill the current void in pharmaceutical development in the short term. This review outlines the most promising strategies that could be implemented to solve the threat of multidrug-resistant Gram-negative infections