Potential of bacteriophage ΦaB2 as an environmental biocontrol agent for the control of multidrug-resistant Acinetobacter baumannii

Abstract

Background: Multidrug-resistant Acinetobacter baumannii (MDRAB) is associated with nosocomial infections worldwide. To date, the use of a phage to prevent infections caused by MDRAB has not been demonstrated. Results: The MDRAB-specific phage φAB2 was stable at 4°C and pH 7 in 0.5% chloroform solution, and showed a slight decrease in plaque-forming units (PFU)/ml of 0.3-0.9 log after 330 days of storage. The addition of φAB2 at a concentration of at least 105 PFU/ml to an A. baumannii M3237 suspension killed >99.9% of A. baumannii M3237 after 5 min, regardless of A. baumannii M3237 concentration (104, 105, or 106 colony-forming units (CFU)/ml). The addition of φAB2 at a concentration of 108 PFU/slide (>107 PFU/cm2) to glass slides containing A. baumannii M3237 at 104, 105, or 10 6 CFU/slide, significantly reduced bacterial numbers by 93%, 97%, and 99%, respectively. Thus, this concentration is recommended for decontamination of glass surfaces. Moreover, infusion of φAB2 into 10% glycerol exhibited strong anti-MDRAB activity (99.9% reduction), even after 90 days of storage. Treatment of a 10% paraffin oil-based lotion with φAB2 significantly reduced (99%) A. baumannii M3237 after 1 day of storage. However, φAB2 had no activity in the lotion after 1 month of storage. Conclusions: Phages may be useful for reducing MDRAB contamination in liquid suspensions or on hard surfaces. Phages may also be inoculated into a solution to produce an antiseptic hand wash. However, the phage concentration and incubation time (the duration of phage contact with bacteria) should be carefully considered to reduce the risk of MDRAB contamination. © 2013 Chen et al.; licensee BioMed Central Ltd.