1. Identification and characterization of the capsule depolymerase Dpo27 from phage IME-Ap7 specific to Acinetobacter pittii .
- Author
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Wang R, Liu Y, Zhang Y, Yu S, Zhuo H, Huang Y, Lyu J, Lin Y, Zhang X, Mi Z, and Liu Y
- Subjects
- Humans, Bacterial Capsules metabolism, Bacterial Capsules genetics, Bacteriophages genetics, Bacteriophages enzymology, Bacteriophages isolation & purification, Acinetobacter enzymology, Acinetobacter genetics, Acinetobacter virology, Acinetobacter drug effects, Acinetobacter Infections microbiology, Glycoside Hydrolases genetics, Glycoside Hydrolases metabolism
- Abstract
Among the Acinetobacter genus, Acinetobacter pittii stands out as an important opportunistic infection causative agent commonly found in hospital settings, which poses a serious threat to human health. Recently, the high prevalence of carbapenem-resistant A. pittii isolates has created significant therapeutic challenges for clinicians. Bacteriophages and their derived enzymes are promising therapeutic alternatives or adjuncts to antibiotics effective against multidrug-resistant bacterial infections. However, studies investigating the depolymerases specific to A. pittii strains are scarce. In this study, we identified and characterized a capsule depolymerase, Dpo27, encoded by the bacteriophage IME-Ap7, which targets A. pittii . A total of 23 clinical isolates of Acinetobacter spp. were identified as A. pittii (21.91%, 23/105), and seven A. pittii strains with various K locus (KL) types (KL14, KL32, KL38, KL111, KL163, KL207, and KL220) were used as host bacteria for phage screening. The lytic phage IME-Ap7 was isolated using A. pittii 7 (KL220) as an indicator bacterium and was observed for depolymerase activity. A putative tail fiber gene encoding a polysaccharide-degrading enzyme (Dpo27) was identified and expressed. The results of the modified single-spot assay showed that both A. pittii 7 and 1492 were sensitive to Dpo27, which was assigned the KL220 type. After incubation with Dpo27, A. pittii strain was susceptible to killing by human serum; moreover, the protein displayed no hemolytic activity against erythrocytes. Furthermore, the protein exhibited sustained activity across a wide pH range (5.0-10.0) and at temperatures between 20 and 50°C. In summary, the identified capsule depolymerase Dpo27 holds promise as an alternative treatment for combating KL220-type A. pittii infections., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Wang, Liu, Zhang, Yu, Zhuo, Huang, Lyu, Lin, Zhang, Mi and Liu.)
- Published
- 2024
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