Potential application of bacteriophage to control carbapenem-resistant Acinetobacter baumannii isolated from inanimate hospital surfaces

Acinetobacter baumannii is one of the most crucial pathogens causing nosocomial infections in hospitals due to its simplicity of extraordinarily evolving multi-drug resistance. This study aimed to isolate carbapenem-resistant Acinetobacter baumannii (CRAB) from inanimate hospital surfaces and evaluate the efficacy of a newly isolated phage in combating these isolates. A selective and differential chromogenic culture medium, CHROMagar™ Acinetobacter was used for selective isolation of CRAB, followed by MALDI-TOF to identify the isolate, the Vitek 2 system to determine their antibiograms, and PCR to detect the carbapenemase genes. Furthermore, an Acinetobacter-specific phage was characterized and isolated from sewage using the enrichment technique. Results revealed the isolation of 38 carbapenem-resistant Acinetobacter spp. Of these, 30 isolates were identified as A. baumannii and their antibiograms showed high levels of resistance against various categories of antibiotics. All the investigated isolates harbor two carbapenemase genes, blaOXA-51 and blaOXA-23. Moreover, the isolated phage ϕAB1.1 exhibited high specificity to various isolates of A. baumannii and did not infect other bacterial species. The phage was stable at temperatures up to 60 °C and over the pH range between 5.0 to 11.0. These findings suggested the potential application of ϕAB1.1 as a promising agent to control CRAB.