The impact of phage infection on the morphological characteristics of Acinetobacter baumannii

Abstract

Background: Acinetobacter baumannii, as one of the most dangerous multidrug-resistant (MDR) pathogens has become a critical concern due to its ability to escape the modern health antibiotics. Phage therapy emerges as a promising alternative due to its specificity, abundancy, and effectiveness to address MDR pathogens.

Objectives: This study aimed to determine the killing profile of A. baumannii phages and characterize the phageinduced morphological change towards A. baumannii clinical isolates.

Methods: Phages were enriched using double layer agar method. Host range and efficiency of plating (EOP) were determined by performing a spot assay. Killing profile was identified with killing assay and morphological characteristics of infected cells were observed with fluorescence microscopy and analyzed by performing single cell analysis.

Results: The results indicate the broad host range of the six phages to clinical isolates. Phage phiAB014 was found to have a finer average of EOP value compared to the other phages and then selected for further characterization. Killing assay revealed that phiAB014 could inhibit the growth of bacteria in longer incubation time by 10-fold reduction compared to control. Furthermore, phiAB014 could induce several morphological changes of the infected cells indicating that phiAB014 possibly infect the host through several hijacking mechanisms.

Conclusion: This study revealed that phiAB014 with its killing profile could inhibit the bacteria growth favorably and induce the morphological change of the bacteria. All the properties of phiAB014 demonstrate the promising phage therapy as an alternative to antibiotics