A friend described quorum-sensing(QS) bacteria nicely as “A few bacteria will play nice. But once a certain population level is reached, bacteria can sense that they have a quorum, and the metaphorical fangs come out.” Bacteria gives off and detect chemicals as a means of communication. As the concentration changes, the bacteria behavior will change. Once they sense they dominate, they rule! A New Scientist article describes them as “hunt in packs like wolves.”
What does this mean in simple terms: bacteria are not simple mechanical items, but flexible living organisms with complex life-style and behaviors.
“Quorum sensing (QS) is cell communication that is widely used by bacterial pathogens to coordinate the expression of several collective traits, including the production of multiple virulence factors, biofilm formation, and swarming motility once a population threshold is reached. Several lines of evidence indicate that QS enhances virulence of bacterial pathogens in animal models as well as in human infections;” 
Defeating QS is a new area of research. Items that disrupts the signalling chemicals A few items that appear to be effective is:
- Tannic Acid 
- Dietary phytochemicals : turmeric, cabbage, broccoli, mustard, horseradish and wasabi [source 2014]
- Phyllanthus amarus 
- “Quercetin can act as a competitive inhibitor for signaling compound towards LasR receptor pathway and can serve as a novel QS-based antibacterial/anti-biofilm drug to manage food-borne pathogens.” 
- “plant phenolic acids cinnamic acid (CA) and salicylic acid (SA)” 
- Zingerone (related to ginger but not in raw ginger) “The results of the present study revealed the anti-quorum sensing activity of zingerone targeting ligand-receptor interaction, hence proposing zingerone as a suitable anti-virulent drug candidate against P. aeruginosa infections” 
- Burdock root extracts limit quorum-sensing-controlled phenotypes and biofilm architecture in major urinary tract pathogens.
- “curcumin from Curcuma longa (turmeric) was shown to inhibit the biofilm formation of uropathogen” 
- “a methanol extract (and hexane extract derived from it) of the medicinal plant Hyptis suaveolens (L.)” 
- Oregano essential oil-pectin edible films as anti-quorum sensing and food antimicrobial agents. 
Do not use Vinegar (Acetic Acid) in the house or on food. “we demonstrate that the bacterium Bacillus subtilis uses one such volatile, acetic acid, as a quorum-sensing-like signal to coordinate the timing of the formation of structurally complex cell communities, also known as biofilms.” 
- “Twenty-two compounds inhibited QS, while seven promoted the QS to a variable extent in Chromobacterium violaceum and Pseudomonas aeruginosa.” The impact of plant volatiles on bacterial quorum sensing.  Full text.
If you use any aromatic oils or volatile liquids (easy to evaporate) you may wish to research each one on PubMed. Some may encourage infections.