Investigation of Phylogeny and Drug Resistance Mechanisms of Isolated from Blood and Lower Respiratory Tract.

species are environmental bacteria associated with opportunistic infections in vulnerable populations. Traditionally, was considered the predominant pathogenic species. However, commercial identification systems have routinely misidentified as , leading to a mischaracterization of clinical strains and an underestimation of the role of in human disease. spp. harbor multidrug resistance (MDR) genes that pose challenges for treatment. Differentiation between spp. is particularly important due to differences in antimicrobial resistance (AMR) and epidemiological investigation. In this study, we describe a case of MDR isolated from the blood and lower respiratory tract of a patient who was successfully treated with minocycline. These isolates were initially misidentified by matrix assisted laser desorption ionization-time of flight as , whereas whole genome sequencing (WGS) confirmed the isolates as with the closest related strain being NUHP1, which was implicated in a 2012 outbreak in Singapore. Several AMR genes (blaBlaB, blaBlaGOB, blaCME, Sul2, erm(F), and catB) were identified by WGS, confirming the mechanisms for MDR. This case emphasizes the utility of WGS for correct speciation, elucidation of resistance genes, and relatedness to other outbreak strains. As is associated with a high mortality and has been found in hospital system sinks, WGS is critically important for determining strain relatedness and tracking outbreaks in the hospital setting.