Potential Anti-staphylococcal Properties of Variovorax Paradoxus EPS

RM 210

Bacteria are ubiquitous to most environments and prokaryotic genes which encode for both antibiotic and antibiotic-resistance pathways are ancient. In addition, environmental microorganisms are reservoirs for resistance genes such as β-lactamase(s) and fluoroquinolone(s). The need for novel antibiotics has risen with the increase in number of bacterial species possessing antibiotic resistance genes. However, approval of novel antibiotics has decreased sharply in the past 30 years with the most commonly given reason for lack of approvals is insufficient economic incentives. Variovorax paradoxus EPS has been observed to have anti-staphylococcal properties when grown in coculture with Staphylococcus aureus. V. paradoxus EPS is a ubiquitous Gram-negative β-proteobacterium and has been identified as a constituent of various soils and pond waters through rRNA based detection. Currently there are no known pathogenic strains of V. paradoxus EPS. Previous genetic analysis of V. paradoxus EPS has identified three loci, at least one of which is suspected to encode for a non-ribosomal peptide synthetase (NRPS) which synthesizes the suspected anti-microbial molecule. We hypothesize that expression at one or more of these loci will correlate with production of this anti-staphylococcal agent and be initiated by exposure to S. aureus. In our current work we are developing assays to qualitatively analyze the killing of GFP S. aureus on agar plates. This will include screening assays to measure cell lysis as well as the use of our transposon library to identify antibiotic synthesis genes. We are also developing assays to quantitatively analyze killing of S. aureus in co-culture.