Human Infections Caused by Flavobacteriales: Clinical Characteristics and Antimicrobial Susceptibility Patterns

Background/Objectives: Bacteria of the order Flavobacteriales are environmental Gram-negative bacilli. Several organisms within the order represent rare but clinically important causes of infection in human hosts, particularly in immunocompromised and hospitalized individuals. Eight genera have been implicated in human infections: Elizabethkingia, Capnocytophaga, Chryseobacterium, Myroides, Bergeyella, Flavobacterium, Empedobacter, and Weeksella. Despite their clinical relevance, there has been, as yet, no consolidated summary of clinical characteristics or resistance patterns across pathogens within the order. Methods: This narrative review examines the currently published data on human infections caused by organisms within Flavobacteriales. 63 sources, including 57 peer-reviewed articles, were included. Results: The clinical associations of infections caused by each of the above genera are discussed. In addition, available antimicrobial resistance data for the same organisms are summarized. Knowledge gaps are identified, including the lack of dedicated antimicrobial susceptibility breakpoints and limited data on rare categories of organisms. Conclusions: Human pathogens within Flavobacteriales display a number of commonalities, including a predilection for immunocompromised hosts, and frequently display resistance to carbapenems and aminoglycosides. Additional studies to better characterize these pathogens and optimize the approach to their treatment are strongly warranted.