Methods for Detecting N-Acyl Homoserine Lactone Production in Acinetobacter baumannii

Tierney, Aimee R. P.; Rather, Philip N.

doi:10.1007/978-1-4939-9118-1_23

Cited by 13 publications

(17 citation statements)

References 5 publications

(5 reference statements)

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“…Agrobacterium tumefaciens -based solid plate assays were carried out to detect AHL production [ 65 ]. Briefly, 500 µL of the homogenate were loaded in a central well of 0.7% LB agar plates supplemented with 40 μg of 5-bromo-3- indolyl-b-D-galactopyranoside (X-Gal) per mL and 250 µL (OD = 2.5) of overnight cultures of Agrobacterium tumefaciens biosensor.…”

Section: Methodsmentioning

confidence: 99%

“…Briefly, 500 µL of the homogenate were loaded in a central well of 0.7% LB agar plates supplemented with 40 μg of 5-bromo-3- indolyl-b-D-galactopyranoside (X-Gal) per mL and 250 µL (OD = 2.5) of overnight cultures of Agrobacterium tumefaciens biosensor. The presence of AHL was determined by the development of the blue color [ 18 , 65 ]. As a positive control, 100 µL of N-Decanoyl-DL-homoserine lactone (C10-AHL) 12.5 mg/mL was utilized.…”

Section: Methodsmentioning

confidence: 99%

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Human Pleural Fluid and Human Serum Albumin Modulate the Behavior of a Hypervirulent and Multidrug-Resistant (MDR) Acinetobacter baumannii Representative Strain

Pimentel

Tuttobene

et al. 2021

Pathogens

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Acinetobacter baumannii is a nosocomial pathogen capable of causing serious infections associated with high rates of morbidity and mortality. Due to its antimicrobial drug resistance profile, A. baumannii is categorized as an urgent priority pathogen by the Centers for Disease Control and Prevention in the United States and a priority group 1 critical microorganism by the World Health Organization. Understanding how A. baumannii adapts to different host environments may provide critical insights into strategically targeting this pathogen with novel antimicrobial and biological therapeutics. Exposure to human fluids was previously shown to alter the gene expression profile of a highly drug-susceptible A. baumannii strain A118 leading to persistence and survival of this pathogen. Herein, we explore the impact of human pleural fluid (HPF) and human serum albumin (HSA) on the gene expression profile of a highly multi-drug-resistant strain of A. baumannii AB5075. Differential expression was observed for ~30 genes, whose products are involved in quorum sensing, quorum quenching, iron acquisition, fatty acid metabolism, biofilm formation, secretion systems, and type IV pilus formation. Phenotypic and further transcriptomic analysis using quantitative RT-PCR confirmed RNA-seq data and demonstrated a distinctive role of HSA as the molecule involved in A. baumannii’s response.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Human Pleural Fluid and Human Serum Albumin Modulate the Behavior of a Hypervirulent and Multidrug-Resistant (MDR) Acinetobacter baumannii Representative Strain

Pimentel

Tuttobene

et al. 2021

Pathogens

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“…The Agrobacterium tumefaciens NT1 (pZLR4) AHL biosensor 25 , 26 , responds to AHLs of chain lengths ranging from C 6 to C 12 27 . The supernatant recovered from ATCC 17978 motility plates incubated in the dark stimulated expression of the β-galactosidase gene from the quorum-directed promoter in A. tumefaciens , indicating the presence of AHLs in this condition (Table 1 ; Fig.…”

Section: Resultsmentioning

confidence: 99%

“…Agrobacterium tumefaciens NT1 (pZLR4), C. subtsugae (formerly C. violaceum ) ATCC 31532 CV026 42 , and C. violaceum ATCC 12472 VIR07 29 , were used to detect the presence of AHLs in A. baumannii cultures recovered from motility plates or biofilm tubes. The A. tumefaciens NT1 (pZLR4) AHL biosensor, which contains a plasmid-localized traG-lacZ fusion (pZLR4) 25 , 26 , responds to AHLs of chain lengths ranging from C6 to C12 27 . C. subtsugae cviI mutant CV026 28 does not produce AHLs, but induces the CviR upon exposure to exogenous short-chain AHLs, which results in rapid synthesis of a visually clear purple pigmentation, violacein.…”

Section: Methodsmentioning

confidence: 99%

Blue light directly modulates the quorum network in the human pathogen Acinetobacter baumannii

Tuttobene

Müller

Blasco

et al. 2021

Sci Rep

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Quorum sensing modulates bacterial collective behaviors including biofilm formation, motility and virulence in the important human pathogen Acinetobacter baumannii. Disruption of quorum sensing has emerged as a promising strategy with important therapeutic potential. In this work, we show that light modulates the production of acyl-homoserine lactones (AHLs), which were produced in higher levels in the dark than under blue light at environmental temperatures, a response that depends on the AHL synthase, AbaI, and on the photoreceptor BlsA. BlsA interacts with the transcriptional regulator AbaR in the dark at environmental temperatures, inducing abaI expression. Under blue light, BlsA does not interact with AbaR, but induces expression of the lactonase aidA and quorum quenching, consistently with lack of motility at this condition. At temperatures found in warm-blooded hosts, the production of AHLs, quorum quenching as well as abaI and aidA expression were also modulated by light, though in this case higher levels of AHLs were detected under blue light than in the dark, in a BlsA-independent manner. Finally, AbaI reduces A. baumannii's ability to kill C. albicans only in the dark both at environmental as well as at temperatures found in warm-blooded hosts. The overall data indicate that light directly modulates quorum network in A. baumannii.

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“…Agrobacterium tumefaciens-based solid plate assays were carried out to detect N-Acyl Homoserine Lactone (AHL) production 31 as described in previous work 24 . Initially, 500 µL of the homogenate were loaded in a central well of 0.7% LB agar plates supplemented with 40 µg of 5-bromo-3-indolyl-b-Dgalactopyranoside (X-Gal) per mL and 250 µL (OD = 2.5) of the overnight culture of Agrobacterium tumefaciens biosensor.…”

Section: N-acyl Homoserine Lactone (Ahl) Detectionmentioning

confidence: 99%

Histone-like Nucleoid-structuring Protein (H-NS) Regulatory Role in Antibiotic Resistance in Acinetobacter Baumannii

Rodgers

Pimentel

et al. 2021

Preprint

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In the multidrug resistant (MDR) pathogen Acinetobacter baumannii the global repressor H-NS was shown to modulate the expression of genes related to quorum sensing, biosynthetic pathways, cell adhesion, virulence, and autotransporters. In addition, H-NS is involved in stress response and its inactivation results in an increased resistance to colistin, and in a hypermotile phenotype an altered stress response. To further contribute to the knowledge of this key transcriptional regulator in A. baumannii behavior, we studied the role of H-NS in antimicrobial resistance. Using two well characterized A. baumannii model strains with distinctive resistance profile and pathogenicity traits (AB5075 and A118), complementary transcriptomic and phenotypic approaches were used to study the role of H-NS in antimicrobial resistance, biofilm and quorum sensing gene expression. An increased expression of genes associated with β-lactam resistance, aminoglycosides, quinolones, chloramphenicol, trimethoprim and sulfonamides resistance in the Δhns mutant background was observed. Genes codifying for efflux pumps were also up-regulated, with the exception of adeFGH. The wild-type transcriptional level was restored in the complemented strain. In addition, the expression of biofilm related genes and biofilm production was lowered when the transcriptional repressor was absent. The quorum network genes aidA, abaI, kar and fadD were up-regulated in Δhns mutant strains. Overall, our results showed the complexity and scope of the regulatory network control by H-NS (genes involved in antibiotic resistance and persistence). These observations brings us one step closer to understanding the regulatory role of hns to combat A. baumannii infections.

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Methods for Detecting N-Acyl Homoserine Lactone Production in Acinetobacter baumannii

Cited by 13 publications

References 5 publications

Human Pleural Fluid and Human Serum Albumin Modulate the Behavior of a Hypervirulent and Multidrug-Resistant (MDR) Acinetobacter baumannii Representative Strain

Human Pleural Fluid and Human Serum Albumin Modulate the Behavior of a Hypervirulent and Multidrug-Resistant (MDR) Acinetobacter baumannii Representative Strain

Blue light directly modulates the quorum network in the human pathogen Acinetobacter baumannii

Histone-like Nucleoid-structuring Protein (H-NS) Regulatory Role in Antibiotic Resistance in Acinetobacter Baumannii

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