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Microbes and Infection Sep 2016The molecular and genetic basis of Acinetobacter baumannii and Acinetobacter pittii virulence remains poorly understood, and there is still lack of knowledge in host...
The molecular and genetic basis of Acinetobacter baumannii and Acinetobacter pittii virulence remains poorly understood, and there is still lack of knowledge in host cell response to these bacteria. In this study, we have used eleven clinical Acinetobacter strains (A. baumannii n = 5; A. pittii n = 6) to unravel bacterial adherence, invasion and cytotoxicity to human lung epithelial cells. Our results showed that adherence to epithelial cells by Acinetobacter strains is scarce and cellular invasion was not truly detected. In addition, all Acinetobacter strains failed to induce any cytotoxic effect on A549 cells.
Topics: A549 Cells; Acinetobacter; Acinetobacter Infections; Bacterial Adhesion; Cell Survival; Epithelial Cells; Humans; Pneumonia, Bacterial
PubMed: 27235198
DOI: 10.1016/j.micinf.2016.05.002 -
Antimicrobial Agents and Chemotherapy Apr 2018Understanding bacterial pathogenesis requires adequate genetic tools to assess the role of individual virulence determinants by mutagenesis and complementation assays,...
Understanding bacterial pathogenesis requires adequate genetic tools to assess the role of individual virulence determinants by mutagenesis and complementation assays, as well as for homologous and heterologous expression of cloned genes. Our knowledge of pathogenesis has so far been limited by the scarcity of genetic tools to manipulate multidrug-resistant (MDR) epidemic strains, which are responsible for most infections. Here, we report on the construction of new multipurpose shuttle plasmids, namely, pVRL1 and pVRL2, which can efficiently replicate in spp. and in The pVRL1 plasmid has been constructed by combining (i) the cryptic plasmid pWH1277 from , which provides an origin of replication for spp.; (ii) a ColE1-like origin of replication; (iii) the gentamicin or zeocin resistance cassette for antibiotic selection; and (iv) a multilinker containing several unique restriction sites. Modification of pVRL1 led to the generation of the pVRL2 plasmid, which allows arabinose-inducible gene transcription with an undetectable basal expression level of cloned genes under uninduced conditions and a high dynamic range of responsiveness to the inducer. Both pVRL1 and pVRL2 can easily be selected in MDR , have a narrow host range and a high copy number, are stably maintained in spp., and appear to be compatible with indigenous plasmids carried by epidemic strains. Plasmid maintenance is guaranteed by the presence of a toxin-antitoxin system, providing more insights into the mechanism of plasmid stability in spp.
Topics: Acinetobacter; Anti-Bacterial Agents; Bleomycin; Escherichia coli; Genetic Vectors; Gentamicins; Plasmids
PubMed: 29339383
DOI: 10.1128/AAC.02480-17 -
Microbiology and Molecular Biology... Jun 2010Within the last 15 years, members of the bacterial genus Acinetobacter have risen from relative obscurity to be among the most important sources of hospital-acquired... (Review)
Review
Within the last 15 years, members of the bacterial genus Acinetobacter have risen from relative obscurity to be among the most important sources of hospital-acquired infections. The driving force for this has been the remarkable ability of these organisms to acquire antibiotic resistance determinants, with some strains now showing resistance to every antibiotic in clinical use. There is an urgent need for new antibacterial compounds to combat the threat imposed by Acinetobacter spp. and other intractable bacterial pathogens. The essential processes of chromosomal DNA replication, transcription, and cell division are attractive targets for the rational design of antimicrobial drugs. The goal of this review is to examine the wealth of genome sequence and gene knockout data now available for Acinetobacter spp., highlighting those aspects of essential systems that are most suitable as drug targets. Acinetobacter spp. show several key differences from other pathogenic gammaproteobacteria, particularly in global stress response pathways. The involvement of these pathways in short- and long-term antibiotic survival suggests that Acinetobacter spp. cope with antibiotic-induced stress differently from other microorganisms.
Topics: Acinetobacter; Bacterial Proteins; DNA, Bacterial; Genome, Bacterial; Transcription, Genetic
PubMed: 20508250
DOI: 10.1128/MMBR.00048-09 -
MSphere May 2024is an opportunistic human and animal pathogen severely understudied. Here, we conducted the largest genomic epidemiological study on this pathogen to date. Our data...
UNLABELLED
is an opportunistic human and animal pathogen severely understudied. Here, we conducted the largest genomic epidemiological study on this pathogen to date. Our data show that this bacterium has spread globally. Also, we found that some human and non-human isolates are not well differentiated from one another, implying transmission between clinical and non-clinical, non-human settings. Remarkably, human but also some non-human isolates have clinically important antibiotic resistance genes, and some of these genes are located in plasmids. Given these results, we put forward that should be considered an emerging One Health problem. In this regard, future molecular epidemiological studies about this species will go beyond human isolates and will consider animal-, plant-, and water-associated environments.
IMPORTANCE
is the most well-known species from the genus . However, other much less studied species could be important opportunistic pathogens of animals, plants and humans. Here, we conducted the largest genomic epidemiological study of , which has been described as a source not only of human but also of animal infections. Our analyses show that this bacterium has spread globally and that, in some instances, human and non-human isolates are not well differentiated. Remarkably, some non-human isolates have important antibiotic resistance genes against important antibiotics used in human medicine. Based on our results, we propose that this pathogen must be considered an issue not only for humans but also for veterinary medicine.
Topics: Acinetobacter Infections; Humans; Acinetobacter; Animals; One Health; Genome, Bacterial; Anti-Bacterial Agents; Molecular Epidemiology; Communicable Diseases, Emerging; Drug Resistance, Bacterial; Plasmids; Genomics
PubMed: 38606973
DOI: 10.1128/msphere.00162-24 -
ELife Jan 2020Diverse interactions among species within bacterial colonies lead to intricate spatiotemporal dynamics, which can affect their growth and survival. Here, we describe the...
Diverse interactions among species within bacterial colonies lead to intricate spatiotemporal dynamics, which can affect their growth and survival. Here, we describe the emergence of complex structures in a colony grown from mixtures of motile and non-motile bacterial species on a soft agar surface. Time-lapse imaging shows that non-motile bacteria 'hitchhike' on the motile bacteria as the latter migrate outward. The non-motile bacteria accumulate at the boundary of the colony and trigger an instability that leaves behind striking flower-like patterns. The mechanism of the front instability governing this pattern formation is elucidated by a mathematical model for the frictional motion of the colony interface, with friction depending on the local concentration of the non-motile species. A more elaborate two-dimensional phase-field model that explicitly accounts for the interplay between growth, mechanical stress from the motile species, and friction provided by the non-motile species, fully reproduces the observed flower-like patterns.
Topics: Acinetobacter; Escherichia coli; Friction; Microbial Interactions; Models, Biological; Movement; Stress, Mechanical
PubMed: 31933477
DOI: 10.7554/eLife.48885 -
Frontiers in Cellular and Infection... 2013Acinetobacter baumannii is a significant contributor to intensive care unit (ICU) mortality causing numerous types of infection in this susceptible ICU population, most... (Review)
Review
Acinetobacter baumannii is a significant contributor to intensive care unit (ICU) mortality causing numerous types of infection in this susceptible ICU population, most notably ventilator-associated pneumonia. The substantial disease burden attributed to A. baumannii and the rapid acquisition of antibiotic resistance make this bacterium a serious health care threat. A. baumannii is equipped to tolerate the hostile host environment through modification of its metabolism and nutritional needs. Among these adaptations is the evolution of mechanisms to acquire nutrient metals that are sequestered by the host as a defense against infection. Although all bacteria require nutrient metals, there is diversity in the particular metal needs among species and within varying tissue types and bacterial lifecycles. A. baumannii is well-equipped with the metal homeostatic systems required for the colonization of a diverse array of tissues. Specifically, iron and zinc homeostasis is important for A. baumannii interactions with biotic surfaces and for growth within vertebrates. This review discusses what is currently known regarding the interaction of A. baumannii with vertebrate cells with a particular emphasis on the contributions of metal homeostasis systems. Overall, published research supports the utility of exploiting these systems as targets for the development of much-needed antimicrobials against this emerging infectious threat.
Topics: Acinetobacter baumannii; Animals; Biological Transport; Helicobacter Infections; Homeostasis; Humans; Metabolic Networks and Pathways; Metals; Microbial Viability; Vertebrates
PubMed: 24377089
DOI: 10.3389/fcimb.2013.00095 -
International Journal of Infectious... Aug 2019To determine antimicrobial nonsusceptibility rates for Enterobacteriaceae and Acinetobacter spp. in US hospitals.
OBJECTIVES
To determine antimicrobial nonsusceptibility rates for Enterobacteriaceae and Acinetobacter spp. in US hospitals.
METHODS
We analyzed antimicrobial susceptibilities of non-duplicate Enterobacteriaceae and Acinetobacter spp. isolates reported in 2017 from 375 US hospitals in the BD Insights Research Database. Logistic and Poisson regression modeling methods were used to estimate proportions of resistant isolates and rates per 1000 hospital admissions. National projections were generated based on raking (weighting) methods.
RESULTS
The nationwide proportions of resistant isolates in inpatients were an estimated 12.6%, 6.6%, and 1.2% for Enterobacteriaceae with extended-spectrum beta-lactamase (ESBL), multidrug resistant (MDR), and carbapenem-nonsusceptible (Carb-NS) phenotypes, respectively, and 42.4% and 34.5% for Acinetobacter spp. with MDR and Carb-NS phenotypes. Resistance varied by geographic region and hospital size/type. Estimated nationwide rates per 1000 hospital admissions ranged from a high of 7.1 for ESBL Enterobacteriaceae to a low of 0.3 for Carb-NS Acinetobacter spp. The estimated number of isolates occurring in US inpatients each year was 290,220 ESBL, 173,984 MDR, and 30,194 Carb-NS for Enterobacteriaceae and 12,274 MDR and 9,991 Carb-NS for Acinetobacter spp.
CONCLUSIONS
National prevalence estimates suggest high levels of antimicrobial resistance and a substantial number of patients with resistant Enterobacteriaceae and Acinetobacter spp. in US hospitals.
Topics: Acinetobacter; Anti-Bacterial Agents; Carbapenems; Drug Resistance, Bacterial; Enterobacteriaceae; Hospitalization; Humans; United States
PubMed: 31229615
DOI: 10.1016/j.ijid.2019.06.017 -
Scientific Reports Oct 2021Acinetobacter has been frequently detected in backwater areas of the Three Gorges Reservoir (TGR) region. We here employed Caenorhabditis elegans to perform biosafety...
Acinetobacter has been frequently detected in backwater areas of the Three Gorges Reservoir (TGR) region. We here employed Caenorhabditis elegans to perform biosafety assessment of Acinetobacter strains isolated from backwater area in the TGR region. Among 21 isolates and 5 reference strains of Acinetobacter, exposure to Acinetobacter strains of AC1, AC15, AC18, AC21, A. baumannii ATCC 19606, A. junii NH88-14, and A. lwoffii DSM 2403 resulted in significant decrease in locomotion behavior and reduction in lifespan of Caenorhabditis elegans. In nematodes, exposure to Acinetobacter strains of AC1, AC15, AC18, AC21, A. baumannii, A. junii and A. lwoffii also resulted in significant reactive oxygen species (ROS) production. Moreover, exposure to Acinetobacter isolates of AC1, AC15, AC18, and AC21 led to significant increase in expressions of both SOD-3::GFP and some antimicrobial genes (lys-1, spp-12, lys-7, dod-6, spp-1, dod-22, lys-8, and/or F55G11.4) in nematodes. The Acinetobacter isolates of AC1, AC15, AC18, and AC21 had different morphological, biochemical, phylogenetical, and virulence gene properties. Our results suggested that exposure risk of some Acinetobacter strains isolated from the TGR region exists for environmental organisms and human health. In addition, C. elegans is useful to assess biosafety of Acinetobacter isolates from the environment.
Topics: Acinetobacter; Animals; Caenorhabditis elegans; Containment of Biohazards; Disease Resistance; Host Microbial Interactions; Oxidative Stress; Phylogeny; Rivers; Virulence; Water Microbiology
PubMed: 34611259
DOI: 10.1038/s41598-021-99274-0 -
Infection, Genetics and Evolution :... Sep 2021Acinetobacter spp. may cause difficult-to-treat nosocomial infections due to acquisition of carbapenemases, including New Delhi metallo-β-lactamase (NDM). This genus...
BACKGROUND
Acinetobacter spp. may cause difficult-to-treat nosocomial infections due to acquisition of carbapenemases, including New Delhi metallo-β-lactamase (NDM). This genus has been pointed out as a possible actor in the early dissemination of bla, and this gene has been documented in a variety of species.
OBJECTIVE
Here we describe an Acinetobacter chengduensis (isolate FL51) carrying bla recovered from coastal water in Brazil.
METHODS
In vitro techniques included antimicrobial susceptibility and minimum inhibitory concentration tests, PCR, plasmid profile and matting-out/transformation assays. In silico approaches comprised comparative genomic analyses using appropriate databases.
RESULTS
FL51 grew at room temperature in a variety of culture media, excluding MacConkey. It showed resistance to all beta-lactams tested and to ciprofloxacin. bla was identified, and a single replicon was observed in plasmid profile. In silico DNA hybridization revealed Acinetobacter FL51 as being Acinetobacter chengduensis. bla was flanked upstream by ISAba14-aphA6-ISAba125 and downstream by ble-trpF-Δtat, inserted in a 41,068 bp non typeable plasmid named pNDM-FL51. This replicon showed high coverage and identity with other sequences present in plasmids deposited on the GenBank database, recovered almost exclusively from Acinetobacter spp., associated with hospital settings and animal sources.
CONCLUSION
We described a recently described environmental Acinetobacter species carrying a plasmid-borne bla associated with a Tn125-like structure. Our findings suggest that replicon may play an important role in bla dissemination among distinct settings within this genus and may support the theory of bla emergence from an environmental Acinetobacter.
Topics: Acinetobacter; Bacterial Proteins; Brazil; Drug Resistance, Bacterial; Microbial Sensitivity Tests; Plasmids; Seawater; beta-Lactamases
PubMed: 34020069
DOI: 10.1016/j.meegid.2021.104926 -
Antimicrobial Agents and Chemotherapy May 2014The acquired carbapenem-hydrolyzing oxacillinase (OXA) OXA-143 has thus far been detected only in Acinetobacter baumannii isolates from Brazil. The aim of this study was...
The acquired carbapenem-hydrolyzing oxacillinase (OXA) OXA-143 has thus far been detected only in Acinetobacter baumannii isolates from Brazil. The aim of this study was to characterize three OXA-143 variants: OXA-231 and OXA-253 from carbapenem-resistant A. baumannii isolates and OXA-255 in a carbapenem-susceptible Acinetobacter pittii isolate originating from Brazil, Honduras, and the United States, respectively. The 5' rapid amplification of cDNA ends (RACE) technique identified the same transcription initiation site for all blaOXA-143-like genes and revealed differences in the putative promoter regions. However, all cloned OXA-143 variants conferred carbapenem resistance on A. baumannii ATCC 17978 and OXA-255 conferred carbapenem resistance on A. pittii SH024, which was correlated with blaOXA-255 gene expression. This is the first description of OXA-143-like outside A. baumannii. Detection of OXA-143-like in the United States and Honduras indicates its dissemination through the American continent.
Topics: Acinetobacter; Acinetobacter baumannii; Anti-Bacterial Agents; Carbapenems; Microbial Sensitivity Tests; beta-Lactamases
PubMed: 24566181
DOI: 10.1128/AAC.02618-13