%0 Journal Article %A Nas, Megan Y. %A Cianciotto, Nicholas P. %T Stenotrophomonas maltophilia produces an EntC-dependent catecholate siderophore that is distinct from enterobactin %D 2017 %J Microbiology, %V 163 %N 11 %P 1590-1603 %@ 1465-2080 %R https://doi.org/10.1099/mic.0.000545 %K Stenotrophomonas maltophilia %K enterobactin %K EntC %K salmochelin %K FepA %K siderophore %I Microbiology Society, %X Stenotrophomonas maltophilia, a Gram-negative, multi-drug-resistant bacterium, is increasingly recognized as a key opportunistic pathogen. Thus, we embarked upon an investigation of S. maltophilia iron acquisition. To begin, we determined that the genome of strain K279a is predicted to encode a complete siderophore system, including a biosynthesis pathway, an outer-membrane receptor for ferrisiderophore, and other import and export machinery. Compatible with these data, K279a and other clinical isolates of S. maltophilia secreted a siderophore-like activity when grown at 25–37 °C in low-iron media, as demonstrated by a chrome azurol S assay, which detects iron chelation, and Arnow and Rioux assays, which detect catecholate structures. Importantly, these supernatants rescued the growth of iron-starved S. maltophilia, documenting the presence of a biologically active siderophore. A mutation in one of the predicted biosynthesis genes (entC) abolished production of the siderophore and impaired bacterial growth in low-iron conditions. Inactivation of the putative receptor gene (fepA) prevented the utilization of siderophore-containing supernatants for growth in low-iron conditions. Although the biosynthesis and import loci showed some similarity to those of enterobactin, a well-known catecholate made by enteric bacteria, the siderophore of K279a was unable to rescue the growth of an enterobactin-utilizing indicator strain, and conversely iron-starved S. maltophilia could not use purified enterobactin. Furthermore, the S. maltophilia siderophore displayed patterns of solubility in organic compounds and mobility upon thin-layer chromatography that were distinct from those of enterobactin and its derivative, salmochelin. Together, these data demonstrate that S. maltophilia secretes a novel catecholate siderophore. %U https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.000545