Antibiotic Resistance: Survival Mechanisms of Gram-Negative Bacteria against β-Lactams

Among all pathogenic bacteria, gram-negative bacteria including members of the genera Providencia, Serratia, Pseudomonas, Escherichia, and Klebsiella have been identified to exhibit an incredible evolutionary adaptation to acquire resistance to antibiotics. This is due to their characteristic structure and the ease of evolution of their genome, which is expressed phenotypically. Antibiotic resistance by these bacteria contributes greatly to the global public health crises since infections caused by these pathogens have high morbidity and mortality rates across the globe. Before now, β-lactam antibiotics were known to be very effective antimicrobial agents against these virulent pathogenic gram-negative microorganisms. However, as these microorganisms evolve, they have also developed various survival mechanisms; target bypass/replacement, target site protection, antibiotic efflux pump among others, which have all mediated their resistance to this group of antibiotics. The proper understanding of these mechanisms is critical to the development of new antibiotics, alternative antimicrobial agents, natural derivatives as well as the modification of already existing antibiotics to effectively curb the scourge of antimicrobial resistance among gram-negative bacteria.