Genomic insights into biofilm-associated virulence in extensively drug-resistant Acinetobacter baumannii
Acinetobacter baumannii is a notorious nosocomial pathogen known for its resistance to multiple antimicrobials, with biofilm formation contributing to its persistence in hospital environments. This study characterized biofilm-associated virulence genes in extensively drug-resistant (XDR) A. baumanni...
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Elsevier
2025-01-01
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| Series: | Current Research in Microbial Sciences |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2666517425000951 |
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| author | Made Rai Dwitya Wiradiputra Piyatip Khuntayaporn Krit Thirapanmethee Pagakrong Wanapaisan Mullika Traidej Chomnawang |
| author_facet | Made Rai Dwitya Wiradiputra Piyatip Khuntayaporn Krit Thirapanmethee Pagakrong Wanapaisan Mullika Traidej Chomnawang |
| author_sort | Made Rai Dwitya Wiradiputra |
| collection | DOAJ |
| description | Acinetobacter baumannii is a notorious nosocomial pathogen known for its resistance to multiple antimicrobials, with biofilm formation contributing to its persistence in hospital environments. This study characterized biofilm-associated virulence genes in extensively drug-resistant (XDR) A. baumannii isolates from two distinct lineages, ST2 and ST25, to understand their roles in biofilm formation and antimicrobial resistance. From 135 non-repetitive multidrug-resistant (MDR) clinical isolates collected across Thailand, 15 XDR isolates (14 ST2 and 1 ST25) were selected for further analysis. Whole-genome sequencing (WGS) was performed to identify biofilm-associated genes and sequence polymorphisms. Biofilm formation and motility phenotypes were assessed, and gene expression analysis was evaluated by qRT-PCR. Most isolates (66.7 %) were moderate biofilm formers, and 80 % exhibiting higher biofilm biomass than the reference strain ATCC 19606. Notably, isolates with lower antimicrobial resistance profiles (i.e., relatively more susceptible among XDRs) tended to produce stronger biofilms. Significant variations in key biofilm genes were observed. Specifically, the abaIR quorum-sensing system was absent in 33.3 % of isolates. All ST2 strains carried bap type-2 with 4–11 BC repeats, while ST25 harboured bap type-3. ompA variants also showed lineage specificity (variant V1 in ST2 and V3 in ST25). All isolates harboured type 1 secretion system (T1SS) operon, however an ISAba1 insertion in the tolC in ST25 may impair protein secretion. Additionally, a nonsense mutation at codon 57 (TTA→TAA) in pilA was identified in all ST2 isolates, potentially accounting for the lack of twitching motility. These findings highlight the substantial genetic and phenotypic variability in biofilm-associated genes among XDR A. baumannii, providing insights into their persistence in healthcare settings. |
| format | Article |
| id | doaj-art-8b52b8ecdcb04323bdb82ca7d30f7d34 |
| institution | Kabale University |
| issn | 2666-5174 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Current Research in Microbial Sciences |
| spelling | doaj-art-8b52b8ecdcb04323bdb82ca7d30f7d342025-08-20T03:31:28ZengElsevierCurrent Research in Microbial Sciences2666-51742025-01-01910043410.1016/j.crmicr.2025.100434Genomic insights into biofilm-associated virulence in extensively drug-resistant Acinetobacter baumanniiMade Rai Dwitya Wiradiputra0Piyatip Khuntayaporn1Krit Thirapanmethee2Pagakrong Wanapaisan3Mullika Traidej Chomnawang4Antimicrobial Resistance Interdisciplinary Center (AMRIC), Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand; Biopharmaceutical Sciences Program, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, ThailandAntimicrobial Resistance Interdisciplinary Center (AMRIC), Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand; Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, ThailandAntimicrobial Resistance Interdisciplinary Center (AMRIC), Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand; Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, ThailandAntimicrobial Resistance Interdisciplinary Center (AMRIC), Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand; Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, ThailandAntimicrobial Resistance Interdisciplinary Center (AMRIC), Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand; Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand; Corresponding author at: Department of Microbiology, Faculty of Pharmacy, Mahidol University, Bangkok, 10400, Thailand.Acinetobacter baumannii is a notorious nosocomial pathogen known for its resistance to multiple antimicrobials, with biofilm formation contributing to its persistence in hospital environments. This study characterized biofilm-associated virulence genes in extensively drug-resistant (XDR) A. baumannii isolates from two distinct lineages, ST2 and ST25, to understand their roles in biofilm formation and antimicrobial resistance. From 135 non-repetitive multidrug-resistant (MDR) clinical isolates collected across Thailand, 15 XDR isolates (14 ST2 and 1 ST25) were selected for further analysis. Whole-genome sequencing (WGS) was performed to identify biofilm-associated genes and sequence polymorphisms. Biofilm formation and motility phenotypes were assessed, and gene expression analysis was evaluated by qRT-PCR. Most isolates (66.7 %) were moderate biofilm formers, and 80 % exhibiting higher biofilm biomass than the reference strain ATCC 19606. Notably, isolates with lower antimicrobial resistance profiles (i.e., relatively more susceptible among XDRs) tended to produce stronger biofilms. Significant variations in key biofilm genes were observed. Specifically, the abaIR quorum-sensing system was absent in 33.3 % of isolates. All ST2 strains carried bap type-2 with 4–11 BC repeats, while ST25 harboured bap type-3. ompA variants also showed lineage specificity (variant V1 in ST2 and V3 in ST25). All isolates harboured type 1 secretion system (T1SS) operon, however an ISAba1 insertion in the tolC in ST25 may impair protein secretion. Additionally, a nonsense mutation at codon 57 (TTA→TAA) in pilA was identified in all ST2 isolates, potentially accounting for the lack of twitching motility. These findings highlight the substantial genetic and phenotypic variability in biofilm-associated genes among XDR A. baumannii, providing insights into their persistence in healthcare settings.http://www.sciencedirect.com/science/article/pii/S2666517425000951Acinetobacter baumanniiAntimicrobial resistanceBiofilmVirulomeWhole-genome sequencing |
| spellingShingle | Made Rai Dwitya Wiradiputra Piyatip Khuntayaporn Krit Thirapanmethee Pagakrong Wanapaisan Mullika Traidej Chomnawang Genomic insights into biofilm-associated virulence in extensively drug-resistant Acinetobacter baumannii Current Research in Microbial Sciences Acinetobacter baumannii Antimicrobial resistance Biofilm Virulome Whole-genome sequencing |
| title | Genomic insights into biofilm-associated virulence in extensively drug-resistant Acinetobacter baumannii |
| title_full | Genomic insights into biofilm-associated virulence in extensively drug-resistant Acinetobacter baumannii |
| title_fullStr | Genomic insights into biofilm-associated virulence in extensively drug-resistant Acinetobacter baumannii |
| title_full_unstemmed | Genomic insights into biofilm-associated virulence in extensively drug-resistant Acinetobacter baumannii |
| title_short | Genomic insights into biofilm-associated virulence in extensively drug-resistant Acinetobacter baumannii |
| title_sort | genomic insights into biofilm associated virulence in extensively drug resistant acinetobacter baumannii |
| topic | Acinetobacter baumannii Antimicrobial resistance Biofilm Virulome Whole-genome sequencing |
| url | http://www.sciencedirect.com/science/article/pii/S2666517425000951 |
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