Antibacterial drug resistance in Latin America: consequences for infectious disease control

Antibacterial drug resistance is a particularly significant issue in Latin America. This article explores antimicrobial resistance in three classes of clinically important bacteria: gram-positive bacteria, enterobacteria, and nonfermenting gram-negative bacilli. The gram-positive bacteria frequently responsible for infections in humans are for the most part cocci: staphylococci, streptococci (including pneumococci), and enterococci, in both community and hospital settings. This situation is no different in the Region of the Americas. Among the gram-positive bacteria, the causative agents of bacteremia are most commonly strains of coagulase-negative Staphylococcus, followed by enterococci. This report explores the resistance of these species to different antimicrobial drugs, resistance mechanisms in community and hospital strains, and new drugs for treating infections caused by these bacteria. In Latin America, antimicrobial resistance in Enterococcus strains is still a minor problem compared to the situation in the United States. The strains of the genus Streptococcus isolated from respiratory infections are still sensitive to penicillin. Furthermore, the resistance of enterobacteria is extremely important in the Region, particularly because of the broad dissemination of CTX-M extended-spectrum beta-lactamases (ESBL), some of which originated in Latin America. This article analyzes the resistance of Streptococcus pneumoniae, beta-hemolytic streptococci, and viridans group streptococci. Among the nonfermenting gram-negative bacilli, while Pseudomonas aeruginosa strains remain the leading cause of bacteremia, infections caused by strains of Acinetobacter spp. have proliferated extensively in some areas. With regard to antibiotics, several options are available for treating gram-positive bacterial infections. The same cannot be said for infections caused by enterobacteria and nonfermenting gram-negative bacilli, where options for the effective treatment of patients are still insufficient.