Fumigation with a combined quaternary ammonium compound and 2 alcohols after detection of bacterial and fungal air bioburden.

TO THE EDITOR—How best to evaluate the effect of quaternary ammonium compound–based products after detection of postflood bacterial and fungal air bioburden remains uncertain. Thammasat University Hospital (Thailand) closed after severe black-water flooding in 2011; significant resources and costs were associated with hospital closure, reparations, and tiered reopening of select units [1]. In addition, an infectioncontrol surveillance program was created to optimize patient and healthcare worker safety [1]. After flood waters reached a maximum 3-foot height between 14 October and 2 November 2011, hospital units were inspected and reopened during the interval from 2 November 2011 to 31 August 2012. An infection-control protocol for cleaning and area decontamination was performed in accordance with a checklist from the US Centers for Disease Control and Prevention (CDC) [2]. Despite thorough manual environmental cleaning, several units had high bacterial and fungal air bioburden, defined as measurements >500 colonyforming units (CFU)/m [1]. Special area decontamination was then employed on all units that had subsequent high bacterial or fungal air bioburden after thorough manual environmental cleaning, using a nontouch technique of either a hydrogen peroxide vapor or a quaternary ammonium compound– based product [1]. Routine air sampling on a negativepressure hospital unit detected a high bacterial and fungal air bioburden on 1 August 2012, despite special area decontamination with repeated manual cleaning (Table 1). We designed a fumigation protocol, comprised of 2.5% isopropyltridecyl-dimethyl-ammonium (Umonium, Huckert's International, Nivelles, Belgium),