Performance of CHROMagar VRE Medium for the Detection of Airborne Vancomycin-Resistant/SensitiveEnterococcusSpecies

Abstract

Vancomycin-sensitive and vancomycin-resistant Enterococcus (VSE and VRE) species have become a significant health problem. CHROMagar medium, which permits direct, color-based identification of target pathogens, could potentially be used to rapidly monitor airborne VSE and VRE. In this study, the efficiency of CHROMagar VRE medium without vancomycin supplementation (CVSE) for collecting airborne vancomycin-sensitive Enterococcus faecalis was evaluated in a chamber study. Subsequently, the performance of bioaerosol samplers combined with CVSE and CHROMagar VRE (CVRE) was evaluated in a hospital environment, a wastewater treatment plant, and a pig-rearing facility. Our results demonstrated that an Andersen impactor was much more effective than a Nuclepore filter for collecting airborne E. faecalis at relative humidity levels of 30% and 55%. In addition, approximately 10% of the isolated environmental Enterococcus strains were vancomycin-resistant. The average sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the colony identification were 58.5%, 81.3%, 5.5%, and 99.1%, respectively, for CVSE and 100%, 88.3%, 8.4%, and 100%, respectively, for CVRE. These findings indicate that the use of CHROMagar might provide a rapid method for detecting airborne VSE or VRE, shortening the detection time to 24-48 h. However, any mauve-colored colonies recovered on CVSE or CVRE by air sampling should be subjected to further identification tests.

Altered susceptibility to air sampling stress by filtration is related to colistin resistance development inAcinetobacter baumannii

“…The Andersen 1‐STG impactor has a very similar air velocity to that of CFCs, at 23.3 m/s . However, our previous studies demonstrated that the culturable collection efficiency of the Andersen 1‐STG impactor was at least 10 times higher than that of CFCs when sampling for the same bacterial species . These results indicated that even though these air sampling velocities are similar, additional sampling stresses such as desiccation and filter elution caused by CFC sampling cause microbes to significantly lose their culturability.…”

Detection of viable antibiotic-resistant/sensitiveAcinetobacter baumanniiin indoor air by propidium monoazide quantitative polymerase chain reaction

“…In field applications, higher sampling flow rates are needed to detect airborne microbe species present at low concentrations. Although sampling with a Nuclepore filter sampler at 20 l/min was not optimized, it has been used to monitor airborne Mycobacterium tuberculosis (Chen and Li, ), S. aureus (Hsiao et al., ), Enterococcus (Hsiao et al., ), and viruses (Tseng et al., ) in the field. For the Nuclepore filter sampler, the lower CR and VR values compared to impingement sampling reflect the loss of microbial culturability and viability during the sampling processes.…”

“…The purpose of this study was to optimize PMA‐qPCR for detecting viable A. baumannii and subsequently to evaluate the effects of three bioaerosol sampling methods (the AGI‐30 impinger, BioSampler and Nuclepore filter sampler) on A. baumannii recovery by culture, qPCR, and PMA‐qPCR. Based on our experience, relative humidity (RH) may affect the biological efficiency of the samplers when collecting viruses and gram‐positive bacteria (Hsiao et al., , ; Tseng and Li, ). Therefore, airborne samples were taken at three different RH levels (35%, 55%, and 85% RH).…”

Application of a quaternary ammonium agent on surgical face masks before use for pre-decontamination of nosocomial infection-related bioaerosols

“…The challenged bacterial aerosols in this study were Acinetobacter baumannii, Enterococcus faecalis, and Staphylococcus aureus. These bacterial species are highly related to nosocomial infection and can cause airborne dispersal and transmission (Hsiao et al 2012;Hsiao et al 2014;Tseng et al 2015). The predecontamination effects of GS5 were studied and divided into two aspects.…”