Publication: Profiling and characterization of antigenic surface-associated proteins for the identification and differentiation of acinetobacter baumannii from non-baumannii acinetobacter
| dc.contributor.author | Bagudo, Ahmad Ibrahim | |
| dc.date.accessioned | 2025-11-18T07:40:36Z | |
| dc.date.available | 2025-11-18T07:40:36Z | |
| dc.date.issued | 2023-07 | |
| dc.description.abstract | Acinetobacter nosocomial infections is a universal public health care problem. The time taken to diagnose Acinetobacter nosocomial infections and the rate associated mortality is a major drawback in patient management. Members of the ACB complex differ in their biology and antibiotic susceptibility pattern, which significantly impede the proper and prompt treantment of the patient. Hence, there is a need for a rapid and reliable identification test that not only rapidly identify Acinetobacter but can differentiate A. baumannii from A. nosocomialis and A. pittii. Surface-associated proteins (SAPs) proved to be reliable for such task in other bacteria such as Salmonella. Acinetobacter contain in their outer membrane lipopolysaccharides (LPS), which represent useful diagnostic markers. Characterized LPS of Acinetobacter have been shown to be of the smooth (S)-form. Therefore, a possible O-serotyping scheme represents a powerful tool in clinical laboratories to identify Acinetobacter species. The aim of this study was to profile the SAPs of A. baumannii, A. nosocomialis and A. pittii and to determine the antigenicity of the SAPs by Western blot towards identification of potential candidate for the development of rapid diagnostic test using serum from patients infected with A. baumannii, A. nosocomialis and A. pittii as well sera positive with other non-Acinetobacter infections. The SAPs of A. baumannii, A. nosocomialis and A. pittii was profiled using SDS-PAGE, antigenicity of the profiled SAPs was determined by Western Blot techniques. Exclusive SAPs to each of the three species, as well as those SAPs common to the three species (ACB complex) were characterized by LC-MS/MS technique. Result of SDS-PAGE profiles in this study demonstrated that 46.4% of the SAP bands were common to A. baumannii, A. nosocomialis, and A. pittii. The SDS-PAGE SAPs profiling further unveiled the presence of SAP bands (40.9, 36.0, and 34.4 kDa), which are unique to A. baumannii, 55.1 kDa and 33.0 kDa unique to A. nosocomialis, and 43.0 kDa and 35.0 kDa unique to A. pittii. Western blot analysis of the profiled SAPs showed variation in host immune response in all the sera tested. In A. baumannii AB1001, the antigenicity study revealed that 86.4% of the SAPs from SDS-PAGE profiles were antigenic. IgG and IgM detected a higher percentage of 84.2% each, followed by IgA 57.9%. In A. nosocomialis AN1001, 70% of the SAPs profiles from SDS-PAGE were antigenic, of which IgM detected all 100%, IgG ranked the second 92.9%, and then IgA 57.1%. Likewise, in A. pittii AP1001, 90% of the SAPs profiles from SDS-PAGE were antigenic. Among them, IgG detected a higher number (88.8%), IgA (77.8%), and IgM (61.1%). Furthermore, the A. baumannii, A. nosocomialis and A. pittii exclusive SAPs (40.9 and 34.4 kDa; 33.0 and 55.1 kDa and A. pittii 43.0 kDa and 35.0 kDa respectively) were recognised by the IgG, IgM, and IgA. The LC-MS/MS identification of the selected SAPs confirmed that the 34.4, 40.9, 48.7 and 23.0 kDa from A. baumannii were identified as OmpA, Omp38, an elongation factor protein and ribosome-recycling factor protein respectively. Whereas the SAPs of 33.0, 48.7, 55.1, and 23.0 kDa from A. nosocomialis were identified as 30S ribosomal protein, ATP synthetase subunit beta protein, chaperonin protein and 50S ribosomal L4. While the 35.0 kDa and 43.0 kDa from A. pittii were identified as Omp38 and Acinetobacter elongation factor respectively. The identification of antigenic SAPs exclusive to each member of the ACB complex and antigenic SAPs common to all members of the ACB complex could pave way in the development of rapid diagnostic test for the early diagnosis of Acinetobacter infection and differentiation of A. baumannii from A. nosocomialis and A. pittii infection. However, further studies on the species exclusive SAPs need to be carried out in vivo to evaluate the diagnostic performance of these proteins. Therefore, the biomarkers identified in this study can be further developed in the form of rapid test such as dipstick test, enzyme immunoassay or molecular assay, which can be very helpful in diagnosing patients with Acinetobacter infection. | |
| dc.identifier.uri | https://erepo.usm.my/handle/123456789/23111 | |
| dc.language.iso | en | |
| dc.title | Profiling and characterization of antigenic surface-associated proteins for the identification and differentiation of acinetobacter baumannii from non-baumannii acinetobacter | |
| dc.type | Resource Types::text::thesis::doctoral thesis | |
| dspace.entity.type | Publication | |
| oairecerif.author.affiliation | Universiti Sains Malaysia |