Coordinate Hyperproduction of SmeZ and SmeJK Efflux Pumps Extends Drug Resistance in Stenotrophomonas maltophilia

Abstract

ABSTRACTAStenotrophomonas maltophiliamutant that coordinately hyper-expresses three resistance nodulation division-type efflux pump genes,smeZ,smeJ, andsmeK, has been identified. SmeZ is responsible for elevating aminoglycoside MICs; SmeJ and SmeK are jointly responsible for elevating tetracycline, minocycline, and ciprofloxacin MICs and conferring levofloxacin resistance. One clinical isolate with this same phenotype was identified from a sample of six, and the isolate also coordinately hyper-expressessmeZandsmeJK, confirming the clinical relevance of our findings.