Two Acinetobacter baumannii Isolates Obtained From a Fatal Necrotizing Fasciitis Infection Display Distinct Genomic and Phenotypic Characteristics in Comparison to Type Strains

Abstract

Acinetobacter baumannii has been recognized as a critical pathogen that causes severe infections worldwide not only because of the emergence of extensively drug-resistant (XDR) derivatives, but also because of its ability to persist in medical environments and colonize compromised patients. While there are numerous reports describing the mechanisms by which this pathogen acquires resistance genes, little is known regarding A. baumannii’s virulence functions associated with rare manifestations of infection such as necrotizing fasciitis, making the determination and implementation of alternative therapeutic targets problematic. To address this knowledge gap, this report describes the analysis of the NFAb-1 and NFAb-2 XDR isolates, which were obtained at two time points during a fatal case of necrotizing fasciitis, at the genomic and functional levels. The comparative genomic analysis of these isolates with the ATCC 19606T and ATCC 17978 strains showed that the NFAb-1 and NFAb-2 isolates are genetically different from each other as well as different from the ATCC 19606T and ATCC 17978 clinical isolates. These genomic differences could be reflected in phenotypic differences observed in these NFAb isolates. Biofilm, cell viability and flow cytometry assays indicate that all tested strains caused significant decreases in A549 human alveolar epithelial cell viability with ATCC 17978, NFAb-1 and NFAb-2 producing significantly less biofilm and significantly more hemolysis and capacity for intracellular invasion than ATCC 19606T. NFAb-1 and NFAb-2 also demonstrated negligible surface motility but significant twitching motility compared to ATCC 19606T and ATCC 17978, likely due to the presence of pili exceeding 2 µm in length, which are significantly longer and different from those previously described in the ATCC 19606T and ATCC 17978 strains. Interestingly, infection with cells of the NFAb-1 isolate, which were obtained from a premortem blood sample, lead to significantly higher mortality rates than NFAb-2 bacteria, which were obtained from postmortem tissue samples, when tested using the Galleria mellonella in vivo infection model. These observations suggest potential changes in the virulence phenotype of the A. baumannii necrotizing fasciitis isolates over the course of infection by mechanisms and cell processes that remain to be identified.

Characteristics of Cervical Necrotizing Fasciitis (CNF) Patient in Oral and Maxillofacial Surgery Department Rsup Dr Hasan Sadikin: 2 Years Retrospective Study

“…This type of wound requires dressings that have an anti-bacterial effect and can absorb purulent exudate. In this study, it was found that 76.4% of patients with wound dressing therapy only after debridement necrotomy surgery, and 24% of patients with CNF received further reconstructive surgery therapy after debridement necrotomies and the use of wound dressings when the wound bed was good and general condition was stable (Grier, 2021).…”

Exposure to Nanoplastic Particles Enhances Acinetobacter Survival, Biofilm Formation, and Serum Resistance

“…Biofilm forming is an important virulence factor for bacterial pathogen [ 25 ]. Based on crystal violet staining and SEM analysis, exposure to 0.1–10 μg/L NPs did not affect the amount of biofilm formation of A. johnsonii AC15 ( Figure 5 A–C).…”

“…The 96 well microtiter plate assay was used to evaluate biofilm formation [ 25 ]. In each well, 100 μL NPs (0.1–1000 μg/L) and 10 μL A. johnsonii AC15 were added.…”

Understanding bacterial biofilms: From definition to treatment strategies

“…Non-device-related infections also have a significant impact on health problems. Dental plaque ( Rabe et al., 2022 ), urinary tract infections ( Singh et al., 2022 ), cystic fibrosis ( Vandeplassche et al., 2020 ), otitis media ( Bair et al., 2020 ), infective endocarditis ( Han and Poma, 2022 ), tonsillitis ( Klagisa et al., 2022 ), periodontitis ( Prado et al., 2022 ), necrotizing fasciitis ( Grier et al., 2021 ), osteomyelitis ( Huang et al., 2022 ), infective kidney stones ( Fayez Hassan et al., 2021 ), chronic inflammatory diseases ( Wu et al., 2015 ), bacterial vaginitis ( Arroyo-Moreno et al., 2022 ), and bladder infections ( Mirzaei et al., 2020 ) are all examples of non-device-related bacterial biofilm infections.…”