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Lucidi M, Visaggio D, Migliaccio A, Capecchi G, Visca P, Imperi F, Zarrilli R. Pathogenicity and virulence of Acinetobacter baumannii: Factors contributing to the fitness in healthcare settings and the infected host. Virulence 2024; 15:2289769. [PMID: 38054753 PMCID: PMC10732645 DOI: 10.1080/21505594.2023.2289769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 11/27/2023] [Indexed: 12/07/2023] Open
Abstract
Acinetobacter baumannii is a common cause of healthcare-associated infections and hospital outbreaks, particularly in intensive care units. Much of the success of A. baumannii relies on its genomic plasticity, which allows rapid adaptation to adversity and stress. The capacity to acquire novel antibiotic resistance determinants and the tolerance to stresses encountered in the hospital environment promote A. baumannii spread among patients and long-term contamination of the healthcare setting. This review explores virulence factors and physiological traits contributing to A. baumannii infection and adaptation to the hospital environment. Several cell-associated and secreted virulence factors involved in A. baumannii biofilm formation, cell adhesion, invasion, and persistence in the host, as well as resistance to xeric stress imposed by the healthcare settings, are illustrated to give reasons for the success of A. baumannii as a hospital pathogen.
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Affiliation(s)
- Massimiliano Lucidi
- Department of Science, Roma Tre University, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
| | - Daniela Visaggio
- Department of Science, Roma Tre University, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Santa Lucia Foundation IRCCS, Rome, Italy
| | | | | | - Paolo Visca
- Department of Science, Roma Tre University, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Santa Lucia Foundation IRCCS, Rome, Italy
| | - Francesco Imperi
- Department of Science, Roma Tre University, Rome, Italy
- NBFC, National Biodiversity Future Center, Palermo, Italy
- Santa Lucia Foundation IRCCS, Rome, Italy
| | - Raffaele Zarrilli
- Department of Public Health, University of Naples Federico II, Naples, Italy
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Ramesh Sawant A, Pagal S, Prashanth K. Role of the NtrC family response regulator in nitrogen metabolism of Acinetobacter baumannii. Gene 2024; 924:148552. [PMID: 38734189 DOI: 10.1016/j.gene.2024.148552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 05/02/2024] [Accepted: 05/08/2024] [Indexed: 05/13/2024]
Abstract
Acinetobacter baumannii is an important Gram-negative nosocomial pathogen that causes opportunistic infections and employs different mechanisms to survive in the presence of antibiotics in the host. Nutrient limitation is one of the important defense mechanisms of the mammalian immune system to fight against the colonization of pathogens like A. baumannii. The present study describes an NtrC-type Response Regulator (RR) A1S_1978 involved in modulating the metabolism and cell morphology of A. baumannii via a two-component system. This RR was found to be highly conserved in the Acinetobacter and other important Gram-negative pathogens. Sequence analysis reveals that this RR contains an HTH_8 DNA-binding domain. It is also observed that deletion of this RR resulted in elongated cell phenotype and altered colony morphology of A. baumannii. We showed that the ability of A. baumannii to form biofilm and pellicle is partly abolished upon deletion of this response regulator. We showed that mutant strains lacking RR A1S_1978 have diminished growth in the absence of the nitrogen source. The transcriptome analysis of the A1S_1978 deletion mutant revealed that 253 genes were differentially expressed, including 80 genes that were upregulated by at least 2-fold and 173 genes that were down regulated in the ΔA1S_1978 strain. The transcriptome data showed an association between the A1S_1978 RR and key genes related to various nitrogen and amino acid metabolism processes, which was further confirmed by real time PCR analysis. The deletion of this RR leads to a reduction in persister cell formation against ciprofloxacin antibiotic. Taken together the results of this investigation provide significant evidence that the RR A1S_1978 is a global regulator in A. baumannii.
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Affiliation(s)
- Ajit Ramesh Sawant
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - Sudhakar Pagal
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India
| | - K Prashanth
- Department of Biotechnology, School of Life Sciences, Pondicherry University, Pondicherry, India.
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Duller S, Kumpitsch C, Moissl-Eichinger C, Wink L, Koskinen Mora K, Mahnert A. In-hospital areas with distinct maintenance and staff/patient traffic have specific microbiome profiles, functions, and resistomes. mSystems 2024:e0072624. [PMID: 38980054 DOI: 10.1128/msystems.00726-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 06/11/2024] [Indexed: 07/10/2024] Open
Abstract
Hospitals are subject to strict microbial control. Stringent cleaning and confinement measures in hospitals lead to a decrease in microbial diversity, but an increase in resistance genes. Given the rise of antimicrobial resistances and healthcare-associated infections, understanding the hospital microbiome and its resistome is crucial. This study compared the microbiome and resistome at different levels of confinement (CL) within a single hospital. Using amplicon sequencing, shotgun metagenomics, and genome/plasmid reconstruction, we demonstrate that microbial composition differs in a stable way between the CLs and that the most restrictive confinement level CL1 had the lowest microbial but the highest functional diversity. This CL also exhibited a greater abundance of functions related to virulence, disease, defense, and stress response. Comparison of antibiotic resistance also showed differences among CLs in terms of the selection process and specific mechanisms for antimicrobial/antibiotic resistance. The resistances found in the samples of CL1 were mostly mediated via antibiotic efflux pumps and were mainly located on chromosomes, whereas in the other, less restrictive CL antibiotic resistances were more present on plasmids. This could be of particular importance for patient-related areas (CL2), as the potential spread of antibiotic resistances could be a major concern in this area. Our results show that there are differences in the microbiome and resistome even within a single hospital, reflecting room utilization and confinement. Since restrictive confinement selects for resistant microorganisms, strategies are required to deepen our understanding of dynamic processes of microbiome and resistome within hospital environments. IMPORTANCE Effective measures to combat antibiotic resistances and healthcare-associated infections are urgently needed, including optimization of microbial control. However, previous studies have indicated that stringent control can lead to an increase in the resistance capacities of microbiomes on surfaces. This study adds to previous knowledge by focusing on the conditions in a single hospital, resolving the microbiomes and their resistomes in three different confinement levels (CL): operating room, patient-related areas, and non-patient-related areas. We were able to identify stable key taxa; profiled the capacities of taxa, functions, and antimicrobial resistances (AMR); and reconstruct genomes and plasmids in each CL. Our results show that the most restrictive CL indeed had the highest functional diversity, but that resistances were mostly encoded on chromosomes, indicating a lower possibility of resistance spread. However, clever strategies are still required to strike a balance between microbial control and selective pressures in environments where patients need protection.
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Affiliation(s)
- Stefanie Duller
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Christina Kumpitsch
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Christine Moissl-Eichinger
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
| | - Lisa Wink
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Kaisa Koskinen Mora
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
| | - Alexander Mahnert
- D&R Institute of Hygiene, Microbiology and Environmental Medicine, Medical University of Graz, Graz, Austria
- BioTechMed Graz, Graz, Austria
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4
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Bacon EE, Myers KS, Iruegas-López R, Banta AB, Place M, Ebersberger I, Peters JM. Physiological Roles of an Acinetobacter-specific σ Factor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.08.602572. [PMID: 39026751 PMCID: PMC11257525 DOI: 10.1101/2024.07.08.602572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
The Gram-negative pathogen Acinetobacter baumannii is considered an "urgent threat" to human health due to its propensity to become antibiotic resistant. Understanding the distinct regulatory paradigms used by A. baumannii to mitigate cellular stresses may uncover new therapeutic targets. Many γ-proteobacteria use the extracytoplasmic function (ECF) σ factor, RpoE, to invoke envelope homeostasis networks in response to stress. Acinetobacter species contain the poorly characterized ECF "SigAb;" however, it is unclear if SigAb has the same physiological role as RpoE. Here, we show that SigAb is a metal stress-responsive ECF that appears unique to Acinetobacter species and distinct from RpoE. We combine promoter mutagenesis, motif scanning, and ChIP-seq to define the direct SigAb regulon, which consists of sigAb itself, the stringent response mediator, relA, and the uncharacterized small RNA, "sabS." However, RNA-seq of strains overexpressing SigAb revealed a large, indirect regulon containing hundreds of genes. Metal resistance genes are key elements of the indirect regulon, as CRISPRi knockdown of sigAb or sabS resulted in increased copper sensitivity and excess copper induced SigAb-dependent transcription. Further, we found that two uncharacterized genes in the sigAb operon, "aabA" and "aabB", have anti-SigAb activity. Finally, employing a targeted Tn-seq approach that uses CRISPR-associated transposons, we show that sigAb, aabA, and aabB are important for fitness even during optimal growth conditions. Our work reveals new physiological roles for SigAb and SabS, provides a novel approach for assessing gene fitness, and highlights the distinct regulatory architecture of A. baumannii.
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Affiliation(s)
- Emily E. Bacon
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, WI, USA
| | - Kevin S. Myers
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Energy Institute, University of Wisconsin-Madison, Madison, WI, USA
| | - Rubén Iruegas-López
- Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Germany
| | - Amy B. Banta
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Michael Place
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Ingo Ebersberger
- Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Germany
- Senckenberg Biodiversity and Climate Research Centre (S-BIKF), Frankfurt, Germany
- LOEWE Center for Translational Biodiversity Genomics (TBG), Frankfurt, Germany
| | - Jason M. Peters
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, USA
- Great Lakes Bioenergy Research Center, University of Wisconsin-Madison, Madison, WI, USA
- Department of Bacteriology, University of Wisconsin-Madison, Madison, WI, USA
- Department of Medical Microbiology and Immunology, University of Wisconsin-Madison, Madison, WI, USA
- Center for Genomic Science Innovation, University of Wisconsin-Madison, Madison, WI, USA
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5
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Kunkle DE, Cai Y, Eichman BF, Skaar EP. An interstrand DNA crosslink glycosylase aids Acinetobacter baumannii pathogenesis. Proc Natl Acad Sci U S A 2024; 121:e2402422121. [PMID: 38923984 PMCID: PMC11228520 DOI: 10.1073/pnas.2402422121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Accepted: 05/24/2024] [Indexed: 06/28/2024] Open
Abstract
Maintenance of DNA integrity is essential to all forms of life. DNA damage generated by reaction with genotoxic chemicals results in deleterious mutations, genome instability, and cell death. Pathogenic bacteria encounter several genotoxic agents during infection. In keeping with this, the loss of DNA repair networks results in virulence attenuation in several bacterial species. Interstrand DNA crosslinks (ICLs) are a type of DNA lesion formed by covalent linkage of opposing DNA strands and are particularly toxic as they interfere with replication and transcription. Bacteria have evolved specialized DNA glycosylases that unhook ICLs, thereby initiating their repair. In this study, we describe AlkX, a DNA glycosylase encoded by the multidrug resistant pathogen Acinetobacter baumannii. AlkX exhibits ICL unhooking activity similar to that of its Escherichia coli homolog YcaQ. Interrogation of the in vivo role of AlkX revealed that its loss sensitizes cells to DNA crosslinking and impairs A. baumannii colonization of the lungs and dissemination to distal tissues during pneumonia. These results suggest that AlkX participates in A. baumannii pathogenesis and protects the bacterium from stress conditions encountered in vivo. Consistent with this, we found that acidic pH, an environment encountered during host colonization, results in A. baumannii DNA damage and that alkX is induced by, and contributes to, defense against acidic conditions. Collectively, these studies reveal functions for a recently described class of proteins encoded in a broad range of pathogenic bacterial species.
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Affiliation(s)
- Dillon E. Kunkle
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN37232
| | - Yujuan Cai
- Department of Biological Sciences, Vanderbilt University, Nashville, TN37232
| | - Brandt F. Eichman
- Department of Biological Sciences, Vanderbilt University, Nashville, TN37232
- Department of Biochemistry, Vanderbilt University, Nashville, TN37232
| | - Eric P. Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN37232
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN37232
- Department of Biological Sciences, Vanderbilt University, Nashville, TN37232
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Raustad N, Dai Y, Iinishi A, Mohapatra A, Soo MW, Hay E, Hernandez GM, Geisinger E. A phosphorylation signal activates genome-wide transcriptional control by BfmR, the global regulator of Acinetobacter resistance and virulence. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.16.599214. [PMID: 38948834 PMCID: PMC11212878 DOI: 10.1101/2024.06.16.599214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
The nosocomial pathogen Acinetobacter baumannii is a major threat to human health. The sensor kinase-response regulator system, BfmS-BfmR, is essential to multidrug resistance and virulence in the bacterium and represents a potential antimicrobial target. Important questions remain about how the system controls resistance and pathogenesis. Although BfmR knockout alters expression of >1000 genes, its direct regulon is undefined. Moreover, how phosphorylation controls the regulator is unclear. Here, we address these problems by combining mutagenesis, ChIP-seq, and in vitro phosphorylation to study the functions of phospho-BfmR. We show that phosphorylation is required for BfmR-mediated gene regulation, antibiotic resistance, and sepsis development in vivo. Consistent with activating the protein, phosphorylation induces dimerization and target DNA affinity. Integrated analysis of genome-wide binding and transcriptional profiles of BfmR led to additional key findings: (1) Phosphorylation dramatically expands the number of genomic sites BfmR binds; (2) DNA recognition involves a direct repeat motif widespread across promoters; (3) BfmR directly regulates 303 genes as activator (eg, capsule, peptidoglycan, and outer membrane biogenesis) or repressor (pilus biogenesis); (4) BfmR controls several non-coding sRNAs. These studies reveal the centrality of a phosphorylation signal in driving A. baumannii disease and disentangle the extensive pathogenic gene-regulatory network under its control.
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Affiliation(s)
- Nicole Raustad
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Yunfei Dai
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Akira Iinishi
- Antimicrobial Discovery Center, Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Arpita Mohapatra
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Mark W. Soo
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - Everett Hay
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | | | - Edward Geisinger
- Department of Biology, Northeastern University, Boston, MA 02115, USA
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Meng H, Zhang T, Wang Z, Zhu Y, Yu Y, Chen H, Chen J, Wang F, Yu Y, Hua X, Wang Y. High-Throughput Host-Microbe Single-Cell RNA Sequencing Reveals Ferroptosis-Associated Heterogeneity during Acinetobacter baumannii Infection. Angew Chem Int Ed Engl 2024; 63:e202400538. [PMID: 38419141 DOI: 10.1002/anie.202400538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Revised: 02/27/2024] [Accepted: 02/28/2024] [Indexed: 03/02/2024]
Abstract
Interactions between host and bacterial cells are integral to human physiology. The complexity of host-microbe interactions extends to different cell types, spatial aspects, and phenotypic heterogeneity, requiring high-resolution approaches to capture their full complexity. The latest breakthroughs in single-cell RNA sequencing (scRNA-seq) have opened up a new era of studies in host-pathogen interactions. Here, we first report a high-throughput cross-species dual scRNA-seq technology by using random primers to simultaneously capture both eukaryotic and bacterial RNAs (scRandom-seq). Using reference cells, scRandom-seq can detect individual eukaryotic and bacterial cells with high throughput and high specificity. Acinetobacter baumannii (A.b) is a highly opportunistic and nosocomial pathogen that displays resistance to many antibiotics, posing a significant threat to human health, calling for discoveries and treatment. In the A.b infection model, scRandom-seq witnessed polarization of THP-1 derived-macrophages and the intracellular A.b-induced ferroptosis-stress in host cells. The inhibition of ferroptosis by Ferrostatin-1 (Fer-1) resulted in the improvement of cell vitality and resistance to A.b infection, indicating the potential to resist related infections. scRandom-seq provides a high-throughput cross-species dual single-cell RNA profiling tool that will facilitate future discoveries in unraveling the complex interactions of host-microbe interactions in infection systems and tumor micro-environments.
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Affiliation(s)
- Hongen Meng
- Department of Laboratory Medicine of The First Affiliated Hospital & Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 310030, China
| | - Tianyu Zhang
- Department of Laboratory Medicine of The First Affiliated Hospital & Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 310030, China
| | - Zhang Wang
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, People's Republic of China
| | - Yuyi Zhu
- M20 Genomics, Hangzhou, 311121, China
| | - Yingying Yu
- The Second Affiliated Hospital, School of Public Health, Zhejiang University School of Medicine, Hangzhou, 310016, China
| | - Hangfei Chen
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, People's Republic of China
| | - Jiaye Chen
- Department of Laboratory Medicine of The First Affiliated Hospital & Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 310030, China
| | - Fudi Wang
- The Second Affiliated Hospital, School of Public Health, Zhejiang University School of Medicine, Hangzhou, 310016, China
| | - Yunsong Yu
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, People's Republic of China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, 310016, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, 310016, China
| | - Xiaoting Hua
- Department of Infectious Diseases, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, People's Republic of China
- Key Laboratory of Microbial Technology and Bioinformatics of Zhejiang Province, Hangzhou, 310016, China
- Regional Medical Center for National Institute of Respiratory Diseases, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou, 310016, China
| | - Yongcheng Wang
- Department of Laboratory Medicine of The First Affiliated Hospital & Liangzhu Laboratory, Zhejiang University School of Medicine, Hangzhou, 310030, China
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Pérez-Varela M, Singh R, Colquhoun JM, Starich OG, Tierney ARP, Tipton KA, Rather PN. Evidence for Rho-dependent control of a virulence switch in Acinetobacter baumannii. mBio 2024; 15:e0270823. [PMID: 38085026 PMCID: PMC10790780 DOI: 10.1128/mbio.02708-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 10/26/2023] [Indexed: 12/31/2023] Open
Abstract
IMPORTANCE Acinetobacter baumannii is a significant cause of infections in the healthcare setting. More recently, A. baumannii has been a leading cause of secondary bacterial pneumonia in patients infected with SARS-CoV-2 and the overall frequency of A. baumannii infection increased 78% during the COVID-19 pandemic. A. baumannii can exist in virulent or avirulent subpopulations and this interconversion is mediated by the expression of a family of TetR-type transcriptional regulators. In this study, we demonstrate that Rho is a key regulatory component in the expression of these TetR regulators. Overall, this study is the first to address a role for Rho in A. baumannii and provides additional evidence for the role of Rho in regulating diversity in bacterial subpopulations.
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Affiliation(s)
- María Pérez-Varela
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, USA
| | - Raja Singh
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, USA
| | - Jennifer M. Colquhoun
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, USA
- Research Service, Atlanta VA Medical Center, Decatur, Georgia, USA
| | - Olivia G. Starich
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, USA
| | - Aimee R. P. Tierney
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, USA
| | - Kyle A. Tipton
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, USA
| | - Philip N. Rather
- Department of Microbiology and Immunology, Emory University, Atlanta, Georgia, USA
- Research Service, Atlanta VA Medical Center, Decatur, Georgia, USA
- Emory Antibiotic Resistance Center, Emory University, Atlanta, Georgia, USA
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Cook D, Flannigan MD, Chariker JH, Hare JM. DNA damage response coregulator ddrR affects many cellular pathways and processes in Acinetobacter baumannii 17978. Front Cell Infect Microbiol 2024; 13:1324091. [PMID: 38274737 PMCID: PMC10808703 DOI: 10.3389/fcimb.2023.1324091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 12/20/2023] [Indexed: 01/27/2024] Open
Abstract
Introduction Acinetobacter baumannii strain 17978 is an opportunistic pathogen possessing a DNA damage response (DDR) in which multiple error-prone polymerase genes are co-repressed by a UmuD homolog, UmuDAb, and the small Acinetobacter-specific protein DdrR. Additionally, these regulators coactivate nine other genes. We identified the DNA damage-inducible transcriptome for wildtype, umuDAb, and recA strains, and later established the ddrR DDR transcriptome. However, the ATCC 17978 reference genome had several assembly errors and lacked the 44 kb virulence locus, AbaAL44, that is present in the strain 17978 UN. Methods For this project, we combined our earlier single-end read RNAseq data with the ddrR paired-end reads and aligned these data to the improved 17978 UN genome assembly that resembled our laboratory strain, 17978 JH. Results New DESeq2 analyses verified previous differentially expressed genes (DEGs) but also found 339 genes in 17978 JH that were not annotated or physically present in the older genome assembly. Sixty-three were differentially expressed after DNA damage, and 182 had differential basal expression when comparing umuDAb, ddrR, or recA strains to wildtype, with 94 genes' expression unchanged. This work identified and characterized the 55 gene DNA damage-repressible transcriptome, 98% of which required either umuDAb or ddrR for repression. Two-thirds of these DEGs required both regulators. We also identified 110 genes repressed only in the ddrR strain, ~50% of which were due to increased basal expression levels. Basal gene expression in the ddrR mutant was further dysregulated independent of the DDR. Over 800 genes were upregulated, and over 1200 genes were downregulated compared to wildtype expression. Half of A. baumannii's essential genes were upregulated in the ddrR strain, including cell division genes, and two-thirds of these were downregulated in the umuDAb strain. Discussion The ddrR mutant upregulated genes enriched in translation, RNA metabolism, protein metabolism, AA/FA/cell-structure synthesis, and transport, while downregulating genes enriched in quorum sensing, biofilm production, secretion systems, pilus production, cell adhesion, and aromatics and chlorine degradation. Our data underscore the need for accurate and appropriately matched genome assemblies and indicate that ddrR affects approximately 60% of the genome, rendering it a potential target for Acinetobacter baumannii infection treatment.
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Affiliation(s)
- Deborah Cook
- Department of Biology and Chemistry, Morehead State University, Morehead, KY, United States
| | - Mollee D. Flannigan
- Department of Biology and Chemistry, Morehead State University, Morehead, KY, United States
| | - Julia H. Chariker
- Kentucky IDeA Networks of Biomedical Research Excellence (KY INBRE) Bioinformatics Core, University of Louisville, Louisville, KY, United States
| | - Janelle M. Hare
- Department of Biology and Chemistry, Morehead State University, Morehead, KY, United States
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10
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Liang H, Hui S, Chen G, Shen H, Yun J, Zhang L, Lu W, Wu H. Discovery of Deactivation Phenomenon in NiCo 2 S 4 /NiS 2 Electromagnetic Wave Absorbent and Its Reactivation Mechanism. SMALL METHODS 2024:e2301600. [PMID: 38185797 DOI: 10.1002/smtd.202301600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2023] [Revised: 12/28/2023] [Indexed: 01/09/2024]
Abstract
Over the past century, extensive research has been carried out on various types of microwave absorption (MA) materials, primarily emphasizing mechanism, performance, and even toward smart device. However, the deactivation, a crucial concern for practical applications, has long been long-neglected. In this work, an in-depth exploration of the deactivation mechanism reveals a significant competition between metal and oxygen, leading to the replacement of the S-M (M = Ni and Co) bond by a new S─O bond on the surface of absorber. This substitution initiates a series of collapse effect that introduces additional defective sites and diminishes the potential for charge transport. Subsequently, passive and active anti-deactivation strategies are developed to target the deactivation. The passive strategy involved intentionally creating electron-deficient structures at the initial Ni and Co sites in the crystal through the Fe doping engineering, with the objective of preventing the generation of S─O bonds. Furthermore, the active anti-deactivation strategy allows for the precise control of absorber deactivation and reactivation by employing accelerated thermodynamic and kinetic methods, enabling a reversible transformation of S-M through competitive reactions with S─O bonds. Finally, a fast deactivation and reactivation method is first proposed promising to stimulate further innovations and breakthroughs in practical applications.
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Affiliation(s)
- Hongsheng Liang
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, 710072, P. R. China
| | - Shengchong Hui
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, 710072, P. R. China
| | - Geng Chen
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, 710072, P. R. China
| | - Hao Shen
- Department of Applied Physics, School of Science, Chang'an University, Xi'an, 710064, P. R. China
| | - Jijun Yun
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, 710072, P. R. China
| | - Limin Zhang
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, 710072, P. R. China
| | - Wei Lu
- Shanghai Key Lab. of D&A for Metal-Functional Materials, School of Materials Science & Engineering, Tongji University, Shanghai, 201804, P. R. China
| | - Hongjing Wu
- MOE Key Laboratory of Material Physics and Chemistry under Extraordinary, School of Physical Science and Technology, Northwestern Polytechnical University, Xi'an, 710072, P. R. China
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11
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König P, Wilhelm A, Schaudinn C, Poehlein A, Daniel R, Widera M, Averhoff B, Müller V. The VBNC state: a fundamental survival strategy of Acinetobacter baumannii. mBio 2023; 14:e0213923. [PMID: 37768061 PMCID: PMC10653857 DOI: 10.1128/mbio.02139-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/14/2023] [Indexed: 09/29/2023] Open
Abstract
IMPORTANCE Currently, the viable but non-culturable (VBNC) state is an underappreciated niche for pathogenic bacteria which provides a continuous source for recurrent infections and transmission. We propose the VBNC state to be a global persistence mechanism used by various A. baumannii strains to cope with many stresses it is confronted with in the clinical environment and in the host. This requires a novel strategy to detect viable cells of this pathogen that is not only based on plating assays.
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Affiliation(s)
- Patricia König
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University, Frankfurt am Main, Germany
| | - Alexander Wilhelm
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany
| | - Christoph Schaudinn
- Advanced Light and Electron Microscopy ZBS4, Robert-Koch-Institute, Berlin, Germany
| | - Anja Poehlein
- Department of Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August University of Göttingen, Göttingen, Germany
| | - Rolf Daniel
- Department of Genomic and Applied Microbiology & Göttingen Genomics Laboratory, Institute of Microbiology and Genetics, Georg-August University of Göttingen, Göttingen, Germany
| | - Marek Widera
- Institute for Medical Virology, University Hospital Frankfurt, Goethe University, Frankfurt am Main, Germany
| | - Beate Averhoff
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University, Frankfurt am Main, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Goethe-University, Frankfurt am Main, Germany
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12
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Kuczyńska-Wiśnik D, Stojowska-Swędrzyńska K, Laskowska E. Liquid-Liquid Phase Separation and Protective Protein Aggregates in Bacteria. Molecules 2023; 28:6582. [PMID: 37764358 PMCID: PMC10534466 DOI: 10.3390/molecules28186582] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/09/2023] [Accepted: 09/09/2023] [Indexed: 09/29/2023] Open
Abstract
Liquid-liquid phase separation (LLPS) and the formation of membraneless organelles (MLOs) contribute to the spatiotemporal organization of various physiological processes in the cell. These phenomena have been studied and characterized mainly in eukaryotic cells. However, increasing evidence indicates that LLPS-driven protein condensation may also occur in prokaryotes. Recent studies indicate that aggregates formed during proteotoxic stresses may also play the role of MLOs and increase the fitness of bacteria under stress. The beneficial effect of aggregates may result from the sequestration and protection of proteins against irreversible inactivation or degradation, activation of the protein quality control system and induction of dormancy. The most common stress that bacteria encounter in the natural environment is water loss. Therefore, in this review, we focus on protein aggregates formed in E. coli upon desiccation-rehydration stress. In silico analyses suggest that various mechanisms and interactions are responsible for their formation, including LLPS, disordered sequences and aggregation-prone regions. These data support findings that intrinsically disordered proteins and LLPS may contribute to desiccation tolerance not only in eukaryotic cells but also in bacteria. LLPS-driven aggregation may be a strategy used by pathogens to survive antibiotic treatment and desiccation stress in the hospital environment.
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Affiliation(s)
| | | | - Ewa Laskowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (D.K.-W.); (K.S.-S.)
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13
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Maharjan RP, Sullivan GJ, Adams F, Shah B, Hawkey J, Delgado N, Semenec L, Dinh H, Li L, Short F, Parkhill J, Paulsen I, Barquist L, Eijkelkamp B, Cain A. DksA is a conserved master regulator of stress response in Acinetobacter baumannii. Nucleic Acids Res 2023; 51:6101-6119. [PMID: 37158230 PMCID: PMC10325922 DOI: 10.1093/nar/gkad341] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 04/11/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023] Open
Abstract
Coordination of bacterial stress response mechanisms is critical for long-term survival in harsh environments for successful host infection. The general and specific stress responses of well-studied Gram-negative pathogens like Escherichia coli are controlled by alternative sigma factors, archetypically RpoS. The deadly hospital pathogen Acinetobacter baumannii is notoriously resistant to environmental stresses, yet it lacks RpoS, and the molecular mechanisms driving this incredible stress tolerance remain poorly defined. Here, using functional genomics, we identified the transcriptional regulator DksA as a master regulator for broad stress protection and virulence in A. baumannii. Transcriptomics, phenomics and in vivo animal studies revealed that DksA controls ribosomal protein expression, metabolism, mutation rates, desiccation, antibiotic resistance, and host colonization in a niche-specific manner. Phylogenetically, DksA was highly conserved and well-distributed across Gammaproteobacteria, with 96.6% containing DksA, spanning 88 families. This study lays the groundwork for understanding DksA as a major regulator of general stress response and virulence in this important pathogen.
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Affiliation(s)
- Ram P Maharjan
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Geraldine J Sullivan
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Felise G Adams
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Bhumika S Shah
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Jane Hawkey
- Department of Infectious Diseases, Central Clinical School, Monash University, Victoria, Australia
| | - Natasha Delgado
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Lucie Semenec
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Hue Dinh
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Liping Li
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Francesca L Short
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC3800, Australia
| | - Julian Parkhill
- Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge CB3 0ES, UK
| | - Ian T Paulsen
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
| | - Lars Barquist
- Helmholtz Institute for RNA-based Infection Research (HIRI), Helmholtz Centre for Infection Research (HZI), 97080Würzburg, Germany
- Faculty of Medicine, University of Würzburg, 97080Würzburg, Germany
| | - Bart A Eijkelkamp
- College of Science and Engineering, Flinders University, Bedford Park, SA 5042, Australia
| | - Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, Sydney, NSW2109, Australia
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14
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Hariharan V, Chowdhury AR, Rao S S, Chakravortty D, Basu S. phoP maintains the environmental persistence and virulence of pathogenic bacteria in mechanically stressed desiccated droplets. iScience 2023; 26:106580. [PMID: 37168573 PMCID: PMC10164896 DOI: 10.1016/j.isci.2023.106580] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/02/2023] [Accepted: 04/04/2023] [Indexed: 05/13/2023] Open
Abstract
Despite extensive studies on kinematic features of impacting drops, the effect of mechanical stress on desiccated bacteria-laden droplets remains unexplored. In the present study, we unveiled the consequences of the impaction of bacteria-laden droplets on solid surfaces and their subsequent desiccation on the virulence of an enteropathogen Salmonella typhimurium (STM). The methodology elucidated the deformation, cell-cell interactions, adhesion energy, and roughness in bacteria induced by impact velocity and low moisture because of evaporation. Salmonella retrieved from the dried droplets were used to understand fomite-mediated pathogenesis. The impact velocity-induced mechanical stress deteriorated the in vitro viability of Salmonella. Of interest, an uninterrupted bacterial proliferation was observed in macrophages at higher mechanical stress. Wild-type Salmonella under mechanical stress induced the expression of phoP whereas infecting macrophages. The inability of STM ΔphoP to grow in nutrient-rich dried droplets signifies the role of phoP in sensing the mechanical stress and maintaining the virulence of Salmonella.
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Affiliation(s)
- Vishnu Hariharan
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, Karnataka State 560012, India
| | - Atish Roy Chowdhury
- Department of Microbiology & Cell Biology, Indian Institute of Science, Bangalore, Karnataka State 560012, India
| | - Srinivas Rao S
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, Karnataka State 560012, India
| | - Dipshikha Chakravortty
- Department of Microbiology & Cell Biology, Indian Institute of Science, Bangalore, Karnataka State 560012, India
- Indian Institute of Science Education and Research, Thiruvananthapuram, Kerala State 695551, India
- Corresponding author
| | - Saptarshi Basu
- Department of Mechanical Engineering, Indian Institute of Science, Bangalore, Karnataka State 560012, India
- Interdisciplinary Centre for Energy Research (ICER), Indian Institute of Science, Bangalore, Karnataka State 560012, India
- Corresponding author
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15
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Ren X, Palmer LD. Acinetobacter Metabolism in Infection and Antimicrobial Resistance. Infect Immun 2023:e0043322. [PMID: 37191522 DOI: 10.1128/iai.00433-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
Acinetobacter infections have high rates of mortality due to an increasing incidence of infections by multidrug-resistant (MDR) and extensively-drug-resistant (XDR) strains. Therefore, new therapeutic strategies for the treatment of Acinetobacter infections are urgently needed. Acinetobacter spp. are Gram-negative coccobacilli that are obligate aerobes and can utilize a wide variety of carbon sources. Acinetobacter baumannii is the main cause of Acinetobacter infections, and recent work has identified multiple strategies A. baumannii uses to acquire nutrients and replicate in the face of host nutrient restriction. Some host nutrient sources also serve antimicrobial and immunomodulatory functions. Hence, understanding Acinetobacter metabolism during infection may provide new insights into novel infection control measures. In this review, we focus on the role of metabolism during infection and in resistance to antibiotics and other antimicrobial agents and discuss the possibility that metabolism may be exploited to identify novel targets to treat Acinetobacter infections.
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Affiliation(s)
- Xiaomei Ren
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
| | - Lauren D Palmer
- Department of Microbiology and Immunology, University of Illinois Chicago, Chicago, Illinois, USA
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