A new APT binding cassette, multi-resistant gene (ABC MDR) was discovered in 3 strains of bacteria unknown for housing this gene. Bacillus, Paenibacillus and Staphylococcus strains are new vehicles for this horA gene relative. These strains are usually found in the environment and are not known for spoiling beer. ABC MDR is homologous to the horA gene which has been linked with its ability to grow in beer and is already present in Lactobacillus and Pediococcus, which are bacteria that have been known to cause beer spoilage nationwide. In fact, 90% of all batches of spoiled beer tested have one or more strains of these bacteria.

Upon discovery of this homologous gene cassette a multitude of tests were done to make sure this gene was not induced by the new beer environment or other contaminating factors. Two home brewed light and dark beer batches were made and contaminated. This helped obtain four isolates of the newly discovered bacteria vehicles for ABC MDR; Bacillus cereus, Bacillus licheniformis, Paenibacillus humicus and Staphylococcus epidermidis. 16S rRNA PCR was used to identify the strains. Along with the home brews, commercially brewed beer was also tested for bacterial growth of all four strains. Each beer had different alcohol percentages, pH levels and amount of bitterness units. Both beers allowed growth of all 4 bacteria. 

In the brewing industry, turbidity is a measurement of contamination and was therefore used in this experiment. Samples were then tested after turbidity levels were determined to declare it was in fact bacteria spoilage. B. licheniformis took 14 days for turbidity to occur while B. cereus and S. epidermidis took 18 days and P. humicus took 20 days. 

To determine the homologous relationship of this specific ABC MDR to horA a large bp region from all 4 isolates was matched to a library of genes. Less than 37% of the base pair region was matched with known ABC MDR's in other species, however, over 99% of the same base pair region was matched with known horA genes in beer spoiling bacteria. This certain match is the result of a possible natural lateral transfer of genetic material between species or the result of environmental selective pressure of horA gene sequences in Gram-positive bacteria. The horA gene is already known to exist in other lactobacilli within nature but not within the brewing industry.

The discovery of this homologous horA gene in species unknown to beer spoilage is quite a breakthrough. These potential spoilers are a threat to the brewing industry because they are not identified yet as potential spoilers and therefore not tested for in the industry's protocols. The impact of this new vehicle for horA genes not only poses a threat to brewing industries but other fermentation industries such as wine and bread.