The Global Problem of Antibiotic Resistance

Abstract

Amid the recent attention justly focused on the potential problem of microbial sources for weapons of bioterrorism, it is also apparent that human pathogens frequently isolated from infections in patients from community and hospital sources have been growing more resistant to commonly used antibiotics. Much of the growth of multiple-drug-resistant (MDR) bacterial pathogens can be contributed to the overuse of broad-spectrum antimicrobial products. However, an equally troubling and often overlooked component of the problem involves the elegant ways in which pathogenic bacteria continually evolve complex genetic systems for acquiring and regulating an endless array of antibiotic-resistance mechanisms. Efforts to develop new antimicrobials have over the past two decades been woefully behind the rapid evolution of resistance genes developing among both gram-positive and gram-negative pathogens. Several new agents that are best suited for use in the hospital environment have been developed to combat staphylococci resistant to beta-lactam antimicrobials following acquisition of the mecA gene. However, the dramatic spread in the US of the now common community strain of Staphylococcus aureus USA300 has shifted the therapeutic need for new antibiotics useful against MRSA to the community. As the pharmaceutical industry focused on discovering new agents for use against MRSA, hospitals in many parts of the world have seen the emergence of gram-negative pathogens such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Klebsiella pneumoniae that are clinically resistant to almost all available antimicrobials. Such MDR isolates usually contain multiple-resistance determinants, including loss of outer membrane porins via gene inactivation by chromosomally encoded insertion sequences, up-regulation of inate efflux pumps, as well as acquisition of drug-inactivating enzymes whose genes are encoded on self-transmissible plasmids, integrons, and complex transposable elements. These determinants confer a complex resistance phenotype that is often superimposed on mutations in the primary drug target in the cell. The continued evolution of such a complex array of antibiotic-resistance genes presents a formidable challenge at a time when large pharmaceutical companies have scaled down their presence in the anti-infectives arena.

Antimicrobial Susceptibility Pattern of Escherichia Coli Isolates from Clinical Sources at Tertiary Health Care Setting, Ile Ife, South Western Nigeria

“…Despite concerning trend in antimicrobial resistance among E. coli isolates worldwide, a growing armamentarium of antimicrobial agents provides multiple options for treating E. coli infections [5]. In general, monotherapy with trimethoprimsulfamethoxazole, aminoglycosides, cephalosporin or fluoroquinolones is recommended as the treatment of choice for most known infections with E. coli, though many broad spectrum agents (such as beta-lactam/beta lactamase inhibitor combinations and the carbapenems) remain highly active.…”

Antibacterial activity of some African medicinal plants used traditionally against infectious diseases

“…In fact, infections diseases are becoming more difficult to treat due to multi-drug resistant bacteria especially Gram-positive pathogens. There is, therefore, an urgent need for new antibiotics (Gootz, 2010;Marquez, 2005 for their primary healthcare needs, and higher plants are known to play a crucial role in traditional medicine (WHO, 2002). This is the case of Mozambique, where there is a strong dependence on plants as medicines, particularly in the rural areas (Bandeira et al, 2001).…”

Resistance trends and in vitro activity of tigecycline and 17 other antimicrobial agents against Gram-positive and Gram-negative organisms, including multidrug-resistant pathogens, in Germany

“…Despite the many causes for this increase in mortality, the increasing number of bacterial infections caused by resistant pathogens during the last two decades presents one of the greatest challenges to medicine [5,6].…”