There are hundreds of phylogenetically diverse soil bacteria with the capacity to grow on a wide range of antibiotics as their sole carbon source. Some of these bacteria are closely related to human pathogens. The present study evaluates whether there is a barrier that might prevent the penicillin catabolism genes from transferring from the penicillin catabolism strain ABC 07 to the Acinetobacter baylyi strain ADP1. Because of its natural competence and its close relation to the human pathogen Acinetobacter baumanni, ADP1 is an ideal model for the current investigation. ADP1 was transformed with the genomic DNA of ABC 07, Sau3A1 genomic libraries, and Sau3A1 genomic plasmid libraries to test this barrier. None of these methods transformed ADP1 to be a strain with a penicillin catabolism phenotype. In this regard, recent research (Walsh et al., 2013) challenges the concept of bacteria subsisting on antibiotics and argues that the SCS selective medium used in the original study (Dantas et al, 2008) contains 15 mg/L EDTA, which could be the carbon source that sustained the growth of these “antibiotic-eaters.” The present study also tested and verified that ABC 07 can subsist on penicillin, but not EDTA. These results suggest that antibiotic catabolism genes cannot be readily transferred from antibiotic catabolism strains to other bacteria. Future research related to antibiotic catabolism phenotype should attempt computational approaches and system-level molecular methods to identify antibiotic catabolism genes and metabolic pathways before further characterizing their clinical and ecological implications.