Gram-negative bacteria are common causes of infection among the residents of long-term care facilities (LTCFs). Emergence of antimicrobial resistance in the gram-negative bacteria has been a growing problem in nursing homes, hospitals, and even the community. Antibiotic-resistant organisms may be introduced into nursing homes with the admission of new residents who are already colonized or infected. Alternatively, bacterial resistance may emerge in the endogenous ﬂora of residents upon exposure to antimicrobial agents, either through selection of resistant strains or through spontaneous mutation or gene transfer. There is ample evidence that bacterial resistance negatively impacts the outcome of infections. Data from the Centers for Disease Control and Prevention have linked bacterial resistance with higher rates of mortality and morbidity.