Publications by authors named "Chidiebere Akusobi"

Unlabelled: ) is a clinically significant pathogen and a highly genetically diverse species due to its large accessory genome. The functional consequence of this diversity remains unknown mainly because, to date, functional genomic studies in have been primarily performed on reference strains. Given the growing public health threat of infections, understanding the functional genomic differences among clinical isolates can provide more insight into how its genetic diversity influences gene essentiality, clinically relevant phenotypes, and importantly, potential drug targets.

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() presents significant clinical challenges. This study evaluated the synergistic effects of a β-lactam and β-lactamase inhibitor combination against and explored the underlying mechanisms. Synergy was assessed through MIC tests and time-kill studies, and binding affinities of nine β-lactams and BLIs to eight target receptors (L,D-transpeptidases [LDT] 1-5, D,D-carboxypeptidase, penicillin-binding protein [PBP] B, and PBP-lipo) were assessed using mass spectrometry and kinetic studies.

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is a pulmonary pathogen that exhibits intrinsic resistance to antibiotics, but the factors driving this resistance are incompletely understood. Insufficient intracellular drug accumulation could explain broad-spectrum resistance, but whether antibiotics fail to accumulate in and the mechanisms required for drug exclusion remain poorly understood. We measured antibiotic accumulation in using mass spectrometry and found a wide range of drug accumulation across clinically relevant antibiotics.

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Background: Nontuberculous mycobacteria are water-avid pathogens that are associated with nosocomial infections.

Objective: To describe the analysis and mitigation of a cluster of infections in cardiac surgery patients.

Design: Descriptive study.

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Article Synopsis
  • Mycobacterium abscessus infections often occur in cystic fibrosis patients and are difficult to treat due to their resistance to antibiotics.
  • Bacteriophage therapy shows promise but faces challenges, such as varying susceptibility among different strains and the need for personalized treatments.
  • New research on M. abscessus isolates reveals unusual prophage patterns and limited phage infections, highlighting the need for better understanding to improve phage therapy for non-tuberculous mycobacterial infections.
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Mycobacterium abscessus is an emerging pathogen causing lung infection predominantly in patients with underlying structural abnormalities or lung disease and is resistant to most frontline antibiotics. As the pathogenic mechanisms of M. abscessus in the context of the lung are not well-understood, we developed an infection model using air-liquid interface culture and performed a transposon mutagenesis and sequencing screen to identify genes differentially required for bacterial survival in the lung.

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Article Synopsis
  • The study focuses on a rapidly growing non-tuberculous mycobacterium (NTM) that causes various infections, which are hard to treat due to antibiotic resistance.
  • Researchers used transposon sequencing to identify ~362 essential genes for the bacterium's in vitro growth, discovering vulnerabilities that could guide new drug development.
  • One key finding is the importance of the enzyme PBP-lipo, which affects cell wall synthesis; targeting PBP-lipo can enhance the efficacy of certain antibiotics against the bacterium, making it a promising drug target for treating infections.
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  • TnSeq is a key technique used to investigate gene essentiality and interactions in bacteria, specifically focusing on the behavior of the Himar1 transposon at TA dinucleotides.
  • This study reveals that insertion frequencies at TA sites are not random but are influenced by specific nucleotide contexts, which can be modeled to predict insertion patterns with considerable accuracy.
  • An improved method called TTN-Fitness was developed to enhance the identification of essential genes by comparing actual insertion counts to predicted counts, leading to better differentiation between essential and nonessential genes.
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For highly pathogenic viruses, reporter assays that can be rapidly performed are critically needed to identify potentially functional mutations for further study under maximal containment (e.g., biosafety level 4 [BSL-4]).

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The emergence of antibiotic resistance has sparked interest in phage therapy, which uses virulent phages as antibacterial agents. Bacteriophage PP01 has been studied for potential bio-control of O157:H7, its natural host, but in the laboratory, PP01 can be inefficient at killing this bacterium. Thus, the goal of this study was to improve the therapeutic potential of PP01 through short-term experimental evolution.

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