EFFECTIVENESS OF HALOGEN-BASED DISINFECTANTS AGAINST Acinetobacter baumannii: WOUND CARE AND ENVIROMENTAL DECONTAMINATION

Historically, Acinetobacter baumannii has not been considered an important human pathogen. However, a surprisingly high number of multidrugresistant A. baumannii war wound, bloodstream and osteomyelitis infections are occurring in American soldiers injured in Iraq/Kuwait (Operation Iraqi Freedom) and in Afghanistan (Operation Enduring Freedom). Thermal projectiles, (e.g., shrapnel, projectile injuries, or traumatic blast) carry the bacterium directly into combat wounds. Because of its resistance to multiple antibiotics, A. baumannii is emerging as an important pathogen among combat casualty victims and has become a significant clinical disease. With the number of A. baumannii infections rapidly rising, added to A. baumannii’s well-established resistance to multiple antibiotics, underscores the relevance for identifying the most excellent disinfectants for reducing A. baumannii populations in combat wounds and combat health care settings. We compared the bacteriostatic and bactericidal activities of five commercially available U.S. halogenbased disinfectants against A. baumannii, along with a standard E. coli comparator, in a novel bacterial culture system that incorporated a three log range of organic growth media concentrations. We report the highest dilutions of stock disinfectant able to inhibit replication or kill the bacteria, denoted as the maximum inhibitory dilution (MID) and maximum bactericidal dilution (MBD), respectively. For Maximum Inhibitory Dilutions (MID), Stabilized Chlorine Dioxide (SCD) had the highest MID of the five disinfectants tested. BETADINE was nearly equivalent to SCD. SCD and BETADINE had the highest MID values against A. baumannii. SCD was superior against E. coli (p < 0.001) compared to UltraChlorox, Clidox-S, BioClenz, and BETADINE, and showed superior MID activity at high organic concentrations. For Maximum Bactericidal Dilution (MBD), BETADINE was superior against A. baumannii, as well as E. coli (p < 0.001). Overall, the least effective disinfectant against A. baumannii (and E. coli) was UltraChlorox. Among the five disinfectants contrasted, SCD and BETADINE, were superior for the reduction of A. baumanni in samples contaminated with organic material. Chlorine dioxide disinfectants may provide significant bactericidal effects against a range of bacteria to include A baumannii contaminated soldiers. In addition, they may provide a superior disinfecting capability in the healthcare environment, preventing the spread of this and other bacteria.