MRSA strains are resistant to all β-lactam antibiotics, likewise making
treatment a public health problem. ESβL-producing Enterobacteriaceae is similarly a global
issue. These strains are resistant to all newer generation β-lactams with the oxy-imino sidechain
and also to the monobactams. The carbapenem-resistant Enterobactericeae (CRE) are
resistant to all third generation cephalosporins and to at least one carbapenem, the antibiotic
that has been used as a final recourse to treat lethal infections caused by MDR Enterobacteriaceae
species [20]. There is particular concern with regard to CRE primarily because the frequency
of infections with these MDR Gram-negative bacteria is increasing, and the infections
are associated with high mortality rates [21]. Both MβL-producing P. aeruginosa and A. baumannii
are opportunistic pathogens that are often associated with healthcare-acquired infections
with high mortality. Their ability to produce theMβL enzyme in addition to their innate
resistances to various antibacterial agents makes these strains recalcitrant to treatment with
commonly available antimicrobials. The widespread presence of these MDR bacteria calls for
more antimicrobial studies on these medically-important bacteria using alternative sources
such as plant derivatives.