An Overview of the Treatment of Less Common Non-Lactose-Fermenting Gram-Negative Bacteria

Stenotrophomonas maltophilia, Burkholderia cepacia complex, Elizabethkingia spp., Chryseobacterium spp., Achromobacter spp., and Alcaligenes spp. are less-common non-lactose-fermenting bacteria that have emerged as important opportunistic pathogens. Patients at the highest risk for these infections include the immunocompromised, those with cystic fibrosis, and the critically ill. These opportunistic pathogens are frequently drug resistant through the expression of β-lactamases, multidrug efflux pumps, aminoglycoside-modifying enzymes, and target site alterations discussed in detail throughout this review. As a result, treatment is extremely challenging. For each pathogen, this review will examine the epidemiology, mechanisms of resistance, and in vitro and in vivo data including that for novel β-lactam/β-lactamase inhibitors and cefiderocol. Treatment recommendations are provided based on the available literature.