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.
View Article and Find Full Text PDFThe dissemination of multi-drug resistant threatens global healthcare systems and necessitates the development of novel therapeutic options. The Gram-negative bacterial cell envelope provides a first defensive barrier against antimicrobial assault. Essential components of this multi-layered complex are the phospholipid-rich membranes.
View Article and Find Full Text PDFLimited therapeutic options dictate the need for new classes of antimicrobials active against carbapenem-resistant Acinetobacter baumannii. Presented data confirm and extend penicillin binding protein 7/8 (PBP 7/8) as a high-value target in the CR A. baumannii strain HUMC1.
View Article and Find Full Text PDFThe bacterial pathogen Acinetobacter baumannii has emerged as an urgent threat to health care systems. The prevalence of multidrug resistance in this critical human pathogen is closely associated with difficulties in its eradication from the hospital environment and its recalcitrance to treatment during infection. The development of resistance in A.
View Article and Find Full Text PDFAppl Environ Microbiol
October 2021
Acinetobacter species are ubiquitous Gram-negative bacteria that can be found in water, in soil, and as commensals of the human skin. The successful inhabitation of Acinetobacter species in diverse environments is primarily attributable to the expression of an arsenal of stress resistance determinants, which includes an extensive repertoire of metal ion efflux systems. Metal ion homeostasis in the hospital pathogen Acinetobacter baumannii contributes to pathogenesis; however, insights into its metal ion transporters for environmental persistence are lacking.
View Article and Find Full Text PDFis a significant opportunistic pathogen responsible for infections of the lung, blood, skin, urinary tract, and soft tissues, with some strains exhibiting almost complete resistance to commonly used antibiotics. This multidrug resistance, together with a dearth of new antibiotic development, mean novel methods of treatment and prevention are urgently needed. Although many factors required to colonize the host have been identified, little is known about the specific host molecules recognized by these factors.
View Article and Find Full Text PDFBacterial fatty acids are critical components of the cellular membrane. A shift in environmental conditions or in the bacterium's lifestyle may result in the requirement for a distinct pool of fatty acids with unique biophysical properties. This can be achieved by the modification of existing fatty acids or via synthesis.
View Article and Find Full Text PDFAcinetobacter baumannii is one of the world's most problematic nosocomial pathogens. The combination of its intrinsic resistance and ability to acquire resistance markers allow this organism to adjust to antibiotic treatment. Despite being the primary barrier against antibiotic stress, our understanding of the A.
View Article and Find Full Text PDFMaintaining optimal fluidity is essential to ensure adequate membrane structure and function under different environmental conditions. We apply integrated molecular approaches to characterize two desaturases (DesA and DesB) and define their specific roles in unsaturated fatty acid (UFA) production in . Using a murine model, we reveal DesA to play a minor role in colonization of the respiratory tract, whereas DesB is important during invasive disease.
View Article and Find Full Text PDFTreatments for 'superbug' infections are the focus for innovative research, as drug resistance threatens human health and medical practices globally. In particular, Acinetobacter baumannii (Ab) infections are repeatedly reported as difficult to treat due to increasing antibiotic resistance. Therefore, there is increasing need to identify novel targets in the development of different antimicrobials.
View Article and Find Full Text PDFis a ubiquitous Gram-negative bacterium, that is associated with significant disease in immunocompromised individuals. The success of is partly attributable to its high level of antibiotic resistance. Further, expresses a broad arsenal of putative zinc efflux systems that are likely to aid environmental persistence and host colonization, but detailed insights into how the bacterium deals with toxic concentrations of zinc are lacking.
View Article and Find Full Text PDFInsertion sequences (IS) are fundamental mediators of genome plasticity with the potential to generate phenotypic variation with significant evolutionary outcomes. Here, a recently active miniature inverted-repeat transposon element (MITE) was identified in a derivative of ATCC 17978 after being subjected to stress conditions. Transposition of the novel element led to the disruption of the gene, resulting in a characteristic hypermotile phenotype.
View Article and Find Full Text PDFThe Gram-negative opportunistic bacterium is a significant cause of hospital-borne infections worldwide. Alarmingly, the rapid development of antimicrobial resistance coupled with the remarkable ability of isolates to persist on surfaces for extended periods of time has led to infiltration of into our healthcare environments. A major virulence determinant of is the presence of a capsule that surrounds the bacterial surface.
View Article and Find Full Text PDFIn recent years, effective treatment of infections caused by Acinetobacter baumannii has become challenging due to the ability of the bacterium to acquire or up-regulate antimicrobial resistance determinants. Two component signal transduction systems are known to regulate expression of virulence factors including multidrug efflux pumps. Here, we investigated the role of the AdeRS two component signal transduction system in regulating the AdeAB efflux system, determined whether AdeA and/or AdeB can individually confer antimicrobial resistance, and explored the interplay between pentamidine resistance and growth conditions in A.
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