Zoonotic transmission risk of Acinetobacter baumannii from Alaskan wildlife

Abstract

Abstract Introduction/Objective Acinetobacter baumannii is a multi-drug resistant gram-negative bacterium often isolated in water and soil. A challenge in both human and veterinary nosocomial infections, Acinetobacter is adaptable, forming biofilms and carbapenem resistance (CRAB). As an opportunistic infection, Acinetobacter is an emerging pathogen especially in immunocompromised individuals which include marginalized housing insecure populations. Anchorage dedicates large areas for urban park environments providing high impact of human and moose wildlife interaction. Previous studies link zoonotic transmission of bacteria through direct fecal contact or water contamination. The significant number of vulnerable unsheltered individuals in Anchorage using public green belts presents a potential risk for Acinetobacter baumannii colonization. Methods/Case Report To assess environmental Acinetobacter exposure from urban wildlife, we ground collected 150 moose fecal samples between 2019-2022. Samples were placed into support medium, cultured onto MacConkey agar and incubated at 37C. Biochemical identification and antibiotic susceptibility testing were performed using MicroScan™ (Beckman/Coulter Brea, CA) conventional panels with antimicrobial interpretation along clinical laboratory standards (CLSI). Results (if a Case Study enter NA) Acinetobacter baumannii was isolated in moose feces, with proportion of positive samples increasing annually: 7.5% (2019), 12.5% (2020), and 14.2% (2021). Antimicrobial analysis found 100% of samples resistant to cefpodoxime, cefazolin, ceftriaxone, cefuroxime, ampicillin, and ampicillin-sulbactam, with 72% resistant to ertapenem and imipenem. Aztreonam resistance was 22%, cefepime 17%, with only 5% resistant to ciprofloxacin. Conclusion The increasing colonization of moose feces with multi-drug resistant Acinetobacter baumannii potentially poses a significant public health risk in Anchorage, Alaska. With moose inhabiting areas used by the vulnerable homeless and outdoor enthusiasts, there exists a high risk for exposure potential towards opportunistic infection, and colonization. The multi-drug resistance pattern on observed on several of A. baumannii isolates suggests the possibility of CRAB. As one of the five pathogens listed as an urgent threat by the CDC, it is imperative to study potential sources of carbapenem resistant A. baumannii, including environmental exposure. Finding moose fecal samples positive for A. baumannii indicates a need for continued surveillance and risk assessment for community acquired infection.