Disinfectant Susceptibility Profiling of Glutaraldehyde-Resistant Nontuberculous Mycobacteria

Abstract

OBJECTIVEActivated alkaline glutaraldehyde (GTA) remains one of the most widely used high-level disinfectants worldwide. However, several reports have highlighted the potential for nontuberculous mycobacteria to develop high-level resistance to this product. Because aldehyde resistance may lead to cross-resistance to other biocides, we investigated the susceptibility profile of GTA-resistantMycobacterium chelonaeandM. abscessusisolates to various disinfectant chemistries.METHODSHigh-level disinfectants commonly used in the reprocessing of endoscopes and other heat-sensitive, semicritical medical equipment, including different formulations of aldehyde-based products and oxidizing agents, were tested against 10 slow- and fast-growing, GTA-susceptible and GTA-resistant,Mycobacteriumisolates in suspension tests and carrier tests at different temperatures.RESULTSWhile peracetic acid– and hydrogen peroxide–based disinfectants (S40, Resert XL, Reliance DG) efficiently killed all of theMycobacteriumisolates, GTA- and ortho-phthalaldehyde-based products (ie, Cidex, Aldahol, Cidex OPA) showed variable efficacy against GTA-resistant strains despite the ability of some formulations (Aldahol) to overcome the resistance of some of these isolates, especially when the temperature was increased from 20°C to 25°C.CONCLUSIONSApplication permitting, oxidizing chemistries may provide a safe alternative to aldehyde-based products, particularly in GTA-resistant mycobacterial outbreaks.Infect Control Hosp Epidemiol2017;38:784–791