The Influence of Outer Membrane Protein on Ampicillin Resistance of .

The antibiotic resistance of the food-borne pathogen has attracted researchers' attention in recent years, but its molecular mechanism remains poorly understood. In this study, 7 genes encoding outer membrane proteins (OMPs) were individually deleted in ATCC33846, and the resistance of these 7 mutants to 14 antibiotics was investigated. The results revealed that the resistance of the 7 mutants to ampicillin was significantly increased. Further exploration of 20-gene transcription changes by real time-qPCR (RT-qPCR) demonstrated that the higher ampicillin resistance might be attributed to the expression of -lactamase and reduced peptidoglycan (PG) synthesis activity through reduced transcription of penicillin-binding proteins (PBPs), increased transcription of l,d-transpeptidases, downregulated d,d-carboxypeptidase, and alanine deficiency. This study provides a new perspective on ampicillin resistance in OMP mutants with respect to PG synthesis.