Articles of Significant Interest Selected from This Issue by the Editors

doi:10.1128/AEM.03593-15

DOI: 10.1128/AEM.03593-15

Antisense RNA Approach Finally To Unravel the Oenococcus oeni Stress Response

Oenococcus oeni is a wine-associated lactic acid bacterium mostly responsible for malolactic fermentation of wine. Due to the obvious lack of genetic tools for this bacterium, gene disruption is not presently practicable, causing difficulty in understanding the adaptability of O. oeni in hostile environments like wine. Darsonval et al. (p. 18–26) describe a new genetic tool to develop an innovative antisense RNA approach for modulating gene expression. Focusing on expression of the hsp18 gene, encoding the small heat stress protein Lo18, this work demonstrates the tool's effectiveness and the in vivo involvement of Lo18 in the thermotolerance and acid tolerance of O. oeni.

Lysis-Independent Mycobacterial Cell Death Induced by Phage D29

Conventional antibiotic-based strategies to eradicate the mycobacterial disease tuberculosis (TB) have had limited success, owing to the emergence of drug-resistant strains. Conceptually, phage therapy for TB is an attractive alternative. Samaddar et al. (p. 124–133) report here that the viability of mycobacterial cells can be reduced significantly by infecting them with D29, a Mycobacterium-specific lytic phage. The process involves, apart from lysis, a secondary mechanism that depends on the generation of reactive oxygen species (ROS). The information presented can potentially accelerate further development of phage-based therapeutics for TB.

The Spatial Distribution of Bacterial Colonies in Cheese Modulates Their Production of Metabolites during Ripening

During cheese manufacture, the starter lactic acid bacteria grow as colonies. Le Boucher et al. (p. 202–210) explored the consequences of the distribution of colonies in model cheeses containing the same population of lactic acid bacteria distributed as either a few big or numerous small colonies. During ripening, cheeses with big colonies differed slightly, but significantly, from those with small colonies in their concentrations of many metabolites, such as organic acids, peptides, free amino acids, and volatile metabolites, which were more abundant in the latter. This study is of significance for solid fermented foods and other microbial ecosystems.

Employing Whole-Genome Sequencing To Authenticate Clostridium sporogenes PA 3679

Clostridium sporogenes and group I Clostridium botulinum are closely related genetically and physiologically. However, only the putrefactive anaerobe C. sporogenes PA 3679 should be considered as a model organism for group I C. botulinum to validate thermal processes, as it produces highly heat-resistant spores. Schill and colleagues (p. 384–393) employed whole-genome sequencing as well as thermal inactivation studies, which categorized isolates of PA 3679 into two well-separated clades. One clade was found to most accurately represent the original PA 3679 isolate studied in 1927. This study highlights the importance of using molecular techniques to authenticate surrogates and model organisms.

New Implant Coating Preventing Staphylococcus aureus Biofilm Formation by Activating Host Fibrinolytic Response

During implant infection, Staphylococcus aureus induces coagulation to use fibrin deposited by the host as a scaffold for biofilm formation. Kwiecinski et al. (p. 394–401) developed a new type of antibiofilm coating which will prevent this from happening. Tissue plasminogen activator coated on the surface activates host plasminogen to plasmin directly in the vicinity of the implant. Plasmin lyses fibrin clots and thus deprives S. aureus of the essential component of the biofilm scaffold, keeping the surface biofilm-free and preventing implant infections.