Chao-Jung Wu

• National Yang Ming University

Iron is an essential micronutrient for various bacterial cellular processes. Fur is a global transcriptional regulator participating in iron homeostasis. Stenotrophomonas maltophilia is a ubiquitous environmental bacterium that has emerged as an opportunistic pathogen. To elucidate the novel regulatory mechanism behind iron homeostasis in S. maltop...

OmpA, the most abundant porin in Stenotrophomonas maltophilia KJ, exists as a two-domain structure with an N-terminal domain of β-barrel structure embedded in the outer membrane and a C-terminal domain collocated in the periplasm. KJΔOmpA299-356, an ompA mutant of S. maltophilia KJ with a truncated OmpA devoid of 299 to 356 amino acids (aa), was ab...

We report the draft genome sequence of Stenotrophomonas maltophilia strain KJ, which was isolated from a sputum sample from a patient with a respiratory tract infection. Multilocus sequence typing analysis suggested that strain KJ belongs to a novel S. maltophilia sequence type.

Efflux pumps display high efficiency of drug extrusion, which underlies their roles in multidrug resistance. In addition, efflux pumps have physiological functions, and their expression is tightly regulated by various environmental and physiological signals.

Background: Aerobically-grown bacteria can be challenged by hydrogen peroxide stress from endogenous aerobic metabolism and exogenously generated reactive oxygen species. Catalase (Kat), alkyl hydroperoxidase (Ahp), and glutathione peroxidase (Gpx) systems are major adaptive responses to H2O2 stress in bacteria. Stenotrophomonas maltophilia is a u...

Background: Stenotrophomonas maltophilia displays high-level resistance to various antibiotics. Fluoroquinolone is among the few treatment options for S. maltophilia infection. Overexpression of SmeDEF, SmeVWX and SmQnr are the main mechanisms responsible for fluoroquinolone resistance in S. maltophilia. Objectives: To reveal the unidentified fl...

Stenotrophomonas maltophilia is an emerging multi-drug resistant opportunistic pathogen. Although fluoroquinolones (FQ) are still clinically valuable for the treatment of S. maltophilia infection, an increasing prevalence in FQ resistance has been reported. Overexpression of SmeDEF, SmeVWX, and SmQnr, and de-repressed expression of heat shock respo...

Overexpression of resistance-nodulation-division (RND)-type efflux pumps is an important mechanism for bacteria to combat antimicrobials. RND efflux pumps are also critical for bacterial physiology such as oxidative stress tolerance. Stenotrophomonas maltophilia , a multi-drug resistant opportunistic pathogen, harbors eight RND-type efflux pump ope...

SmeYZ efflux pump is a critical pump responsible for aminoglycosides resistance, virulence-related characteristics (oxidative stress susceptibility, motility, and secreted protease activity), and virulence in Stenotrophomonas maltophilia. However, the regulatory circuit involved in SmeYZ expression is little known. A two-component regulatory system...

SmeSy and smeRy form an operon. (DOCX)

Genetic map of six RND-type efflux pumps and their flanking regulatory determinants. (DOCX)

Schematic genomic organization, promoter transcription fusions, and deletion mutants of the smeT-smeDEF and smeSyRy-smeYZ clusters of S. maltophilia. (DOCX)

The domains and conserved phosphorylated residues analysis of SmeSy and SmeRy. (DOCX)

Bacterial strains, plasmids and primers used in this study (DOCX)

Transcriptomic analysis of S. maltophilia wild-type KJ and smeRySy mutant KJΔRSy (DOCX)

Stenotrophomonas maltophilia harbor six lytic transglycosylases (LTs): mltA, mltB1, mltB2, mltD1, mltD2 , and slt . LT deletion increased susceptibility of S. maltophilia to aminoglycosides and macrolides, and the underlying mechanisms were investigated. The expression of AG modifying enzymes and efflux pumps was evaluated by qRT-PCR. Susceptibilit...

Lytic transglycosylases (LTs) are an important class of enzymes involved in the peptidoglycan (PG) cleavage with concomitant formation of an intramolecular 1,6-anhydromuramoyl reaction product. There are six annotated LT genes in Stenotrophomonas maltophilia genome, including five membrane-bound LT (mltA, mltB1, mltB2, mltD1, and mltD2) and a solub...