Standards Development

Scope

This proposal to develop a standard method for the enhanced recovery, isolation, detection and enumeration of Acinetobacter spp. in environmental aquatic niches including agricultural, wastewater effluents, recreational, ground- and well waters. The standardized method is specific for each water type in a specified sample volume e.g., 500 mL of clean water (drinking, recreational, ground- and well water) and 0.1 to 100 mL turbid (agricultural and wastewater effluent). The sample will be membrane filtered (0.45 m). The filter will be placed on Acinetobacter selective growth media and incubated under aerobic and microaerophilic conditions at 30 and 37°C for 18- 24 hours. An inter-laboratory ringtrial will be conducted where each participating country (minimum five) laboratories will simulate a known number of A. baumannii reference strain cells in various environmental water sources. In this stage of ring-trial, raw drinking and post-treated wastewater will be used for the assessment of optimal temperature incubation conditions for enhanced recovery from each substrate. The results will then be analyzed and based on the statistical findings, the optimum sampling and growth conditions will be described for each water type. 

Purpose

Among several bacterial pathogens, A. baumannii has been identified as an emerging opportunistic pathogen that causes nosocomial infections including ventilator-associated pneumonia, bacteremia, and urinary tract infections with high mortality rates worldwide in immunocompromised individuals. A. baumannii is multidrug-resistant to all available antibacterial agents. Other than hospital settings, Acinetobacter spp. are ubiquitous in nature and can be found in different environmental niches such as hydrocarbon-contaminated areas, activated sludge, sewage, and dump sites. Further it has also been isolated on vegetables, animals, and humans. The ability to dominate in so many ecological niches has led to this organism being considered as “microbial weed “ (Cray et al. 2013).

The species of the genus Acinetobacter are strict aerobes and grow under mesophilic conditions based on recent reported findings, it has been observed that A. baumannii was recovered on Campylobacter selective media supplemented with antibiotics at 42°C under microaerophilic conditions in agricultural waters (Fernando et al. 2016). Urgent attention, therefore, is warranted on developing a standard method including optimum incubation conditions and selective growth media using the specified volume of substrate using membrane filtration for enhanced recovery, isolation and detection of Acinetobacter spp. especially when present in low concentrations in various water types. The standard procedure described herein will be used to ensure safe water quality for drinking, irrigation and recreation purposes. Moreover, the standard will be written to ensure that analysts performing the method analysis work in safe and secure format, which is necessarily required for risk group-2 bacterial pathogens. Similarly, the use of standards developed by this Technical Committee will ensure that clean waters are used by the implementation of regulatory and compliance strategies with an assurance that the end-users are protected