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Nature Reviews. Microbiology Feb 2018Acinetobacter baumannii is a nosocomial pathogen that causes ventilator-associated as well as bloodstream infections in critically ill patients, and the spread of... (Review)
Review
Acinetobacter baumannii is a nosocomial pathogen that causes ventilator-associated as well as bloodstream infections in critically ill patients, and the spread of multidrug-resistant Acinetobacter strains is cause for concern. Much of the success of A. baumannii can be directly attributed to its plastic genome, which rapidly mutates when faced with adversity and stress. However, fundamental virulence mechanisms beyond canonical drug resistance were recently uncovered that enable A. baumannii and, to a limited extent, other medically relevant Acinetobacter species to successfully thrive in the health-care environment. In this Review, we explore the molecular features that promote environmental persistence, including desiccation resistance, biofilm formation and motility, and we discuss the most recently identified virulence factors, such as secretion systems, surface glycoconjugates and micronutrient acquisition systems that collectively enable these pathogens to successfully infect their hosts.
Topics: Acinetobacter Infections; Acinetobacter baumannii; Cross Infection; Humans; Virulence
PubMed: 29249812
DOI: 10.1038/nrmicro.2017.148 -
Frontiers in Cellular and Infection... 2017is undoubtedly one of the most successful pathogens responsible for hospital-acquired nosocomial infections in the modern healthcare system. Due to the prevalence of... (Review)
Review
is undoubtedly one of the most successful pathogens responsible for hospital-acquired nosocomial infections in the modern healthcare system. Due to the prevalence of infections and outbreaks caused by multi-drug resistant , few antibiotics are effective for treating infections caused by this pathogen. To overcome this problem, knowledge of the pathogenesis and antibiotic resistance mechanisms of is important. In this review, we summarize current studies on the virulence factors that contribute to pathogenesis, including porins, capsular polysaccharides, lipopolysaccharides, phospholipases, outer membrane vesicles, metal acquisition systems, and protein secretion systems. Mechanisms of antibiotic resistance of this organism, including acquirement of β-lactamases, up-regulation of multidrug efflux pumps, modification of aminoglycosides, permeability defects, and alteration of target sites, are also discussed. Lastly, novel prospective treatment options for infections caused by multi-drug resistant are summarized.
Topics: Acinetobacter Infections; Acinetobacter baumannii; Animals; Biological Therapy; Drug Resistance, Multiple, Bacterial; Humans; Virulence Factors
PubMed: 28348979
DOI: 10.3389/fcimb.2017.00055 -
Molecular Biology Reports Oct 2021Acinetobacter baumannii has become a major concern for scientific attention due to extensive antimicrobial resistance. This resistance causes an increase in mortality... (Review)
Review
Acinetobacter baumannii has become a major concern for scientific attention due to extensive antimicrobial resistance. This resistance causes an increase in mortality rate because strains resistant to antimicrobial agents are a major challenge for physicians and healthcare workers regarding the eradication of either hospital or community-based infections. These strains with emerging resistance are a serious issue for patients in the intensive care unit (ICU). Antibiotic resistance has increased because of the acquirement of mobile genetic elements such as transposons, plasmids, and integrons and causes the prevalence of multidrug resistance strains (MDR). In addition, an increase in carbapenem resistance, which is used as last line antibiotic treatment to eliminate infections with multidrug-resistant Gram-negative bacteria, is a major concern. Carbapenems resistant A. baumannii (CR-Ab) is a worldwide problem. Because these strains are often resistant to all other commonly used antibiotics. Therefore, pathogenic multi-drug resistance A. baumannii (MDR-Ab) associated infections become hard to eradicate. Plasmid-mediated resistance causes outbreaks of extensive drug-resistant. A. baumannii (XDR-Ab). In addition, recent outbreaks relating to livestock and community settings illustrate the existence of large MDR-Ab strain reservoirs within and outside hospital settings. The purpose of this review, proper monitoring, prevention, and treatment are required to control (XDR-Ab) infections. Attachment, the formation of biofilms and the secretion of toxins, and low activation of inflammatory responses are mechanisms used by pathogenic A. baumannii strain. This review will discuss some aspects associated with antibiotics resistance in A. baumannii as well as cover briefly phage therapy as an alternative therapeutic treatment.
Topics: Acinetobacter baumannii; Biofilms; Drug Resistance, Multiple, Bacterial; Hospitals; Host-Pathogen Interactions; Humans; Quorum Sensing; Virulence
PubMed: 34460060
DOI: 10.1007/s11033-021-06690-6 -
Viruses Mar 2023() is one of the most common clinical pathogens and a typical multi-drug resistant (MDR) bacterium. With the increase of drug-resistant infections, it is urgent to... (Review)
Review
() is one of the most common clinical pathogens and a typical multi-drug resistant (MDR) bacterium. With the increase of drug-resistant infections, it is urgent to find some new treatment strategies, such as phage therapy. In this paper, we described the different drug resistances of and some basic properties of phages, analyzed the interaction between phages and their hosts, and focused on phage therapies. Finally, we discussed the chance and challenge of phage therapy. This paper aims to provide a more comprehensive understanding of phages and theoretical support for the clinical application of phages.
Topics: Bacteriophages; Acinetobacter baumannii; Anti-Bacterial Agents
PubMed: 36992382
DOI: 10.3390/v15030673 -
Microbiological Research Jun 2021The Gram-negative opportunistic pathogen Acinetobacter baumannii has gain notoriety in recent decades, primarily due to its propensity to cause nosocomial infections in... (Review)
Review
The Gram-negative opportunistic pathogen Acinetobacter baumannii has gain notoriety in recent decades, primarily due to its propensity to cause nosocomial infections in critically ill patients. Its global spread, multi-drug resistance features and plethora of virulence factors make it a serious threat to public health worldwide. Though much effort has been expended in uncovering its successes, it continues to confound researchers due to its highly adaptive nature, mutating to meet the needs of a given environment. Its persistence in the clinical setting allows it to be in close proximity to a potential host, where contact can be made facilitating infection and colonization. In this article, we aim to provide a current overview of the bacterial virulence factors, specifically focusing on factors involved in the initial stages of infection, highlighting the role of adaptation facilitated by two-component systems and biofilm formation. Finally, the study of host-pathogen interactions using available animal models, their suitability, notable findings and some perspectives moving forward are also discussed.
Topics: Acinetobacter Infections; Acinetobacter baumannii; Animals; Biofilms; Cross Infection; Disease Models, Animal; Drug Resistance, Multiple, Bacterial; Host-Pathogen Interactions; Humans; Sepsis; Virulence Factors
PubMed: 33618061
DOI: 10.1016/j.micres.2021.126722 -
Biomolecules May 2020is a common cause of serious nosocomial infections. Although community-acquired infections are observed, the vast majority occur in people with preexisting... (Review)
Review
is a common cause of serious nosocomial infections. Although community-acquired infections are observed, the vast majority occur in people with preexisting comorbidities. emerged as a problematic pathogen in the 1980s when an increase in virulence, difficulty in treatment due to drug resistance, and opportunities for infection turned it into one of the most important threats to human health. Some of the clinical manifestations of nosocomial infection are pneumonia; bloodstream infections; lower respiratory tract, urinary tract, and wound infections; burn infections; skin and soft tissue infections (including necrotizing fasciitis); meningitis; osteomyelitis; and endocarditis. has an extraordinary genetic plasticity that results in a high capacity to acquire antimicrobial resistance traits. In particular, acquisition of resistance to carbapenems, which are among the antimicrobials of last resort for treatment of multidrug infections, is increasing among strains compounding the problem of nosocomial infections caused by this pathogen. It is not uncommon to find multidrug-resistant (MDR, resistance to at least three classes of antimicrobials), extensively drug-resistant (XDR, MDR plus resistance to carbapenems), and pan-drug-resistant (PDR, XDR plus resistance to polymyxins) nosocomial isolates that are hard to treat with the currently available drugs. In this article we review the acquired resistance to carbapenems by . We describe the enzymes within the OXA, NDM, VIM, IMP, and KPC groups of carbapenemases and the coding genes found in clinical isolates.
Topics: Acinetobacter baumannii; Bacterial Proteins; Carbapenems; Drug Resistance, Bacterial; Enzyme Inhibitors; beta-Lactamases
PubMed: 32384624
DOI: 10.3390/biom10050720 -
Molecules (Basel, Switzerland) May 2019Strains of are commensal and opportunistic pathogens that have emerged as problematic hospital pathogens due to its biofilm formation ability and multiple antibiotic...
Strains of are commensal and opportunistic pathogens that have emerged as problematic hospital pathogens due to its biofilm formation ability and multiple antibiotic resistances. The biofilm-associated pathogens usually exhibit dramatically decreased susceptibility to antibiotics. This study was aimed to investigate the correlation of biofilm-forming ability, antibiotic resistance and biofilm-related genes of 154 isolates which were collected from a teaching hospital in Taiwan. Biofilm-forming ability of the isolates was evaluated by crystal violet staining and observed by scanning electron microscopy. Antibiotic susceptibility was determined by disc diffusion method and minimum inhibitory concentration; the biofilm-related genes were screened by polymerase chain reaction. Results showed that among the 154 tested isolates, 15.6% of the clinical isolates were weak biofilm producers, while 32.5% and 45.4% of them possessed moderate and strong biofilm formation ability, respectively. The experimental results revealed that the multiple drug resistant isolates usually provided a higher biofilm formation. The prevalence of biofilm related genes including , , E and A among the isolated strains was 79.2%, 38.3%, 91.6%, and 68.8%, respectively. The results indicated that the antibiotic resistance, the formation of biofilm and the related genes were significantly correlated. The results of this study can effectively help to understand the antibiotic resistant mechanism and provides the valuable information to the screening, identification, diagnosis, treatment and control of clinical antibiotic-resistant pathogens.
Topics: Acinetobacter baumannii; Anti-Bacterial Agents; Bacterial Proteins; Biofilms; Drug Resistance, Multiple, Bacterial; Gene Expression Regulation, Bacterial; Genetic Association Studies; Microbial Sensitivity Tests; Taiwan
PubMed: 31091746
DOI: 10.3390/molecules24101849 -
Microbes and Infection 2021
Topics: Acinetobacter baumannii; Klebsiella pneumoniae
PubMed: 33892150
DOI: 10.1016/j.micinf.2021.104830 -
International Journal of Molecular... Sep 2022This review briefly summarizes the data on the mechanisms of development of the adaptability of to various living conditions in the environment and in the clinic. A... (Review)
Review
This review briefly summarizes the data on the mechanisms of development of the adaptability of to various living conditions in the environment and in the clinic. A comparative analysis of the genomes of free-living and clinical strains of , as well as the genomes of and has been carried out. It has been shown that plasmids, both large and small, play a key role in the formation of the adaptability of to their living conditions. In particular, it has been demonstrated that the plasmids of various strains of differ from each other in their structure and gene composition depending on the lifestyle of their host bacteria. Plasmids of modern strains are enriched with antibiotic-resistant genes, while the content of genes involved in resistance to heavy metals and arsenic is comparable to plasmids from modern and ancient strains. It is concluded that plasmids may ensure the survival of host bacteria under conditions of various types of environmental and clinical stresses. A brief overview of the main mechanisms of horizontal gene transfer on plasmids inherent in strains is also given.
Topics: Acinetobacter; Acinetobacter baumannii; Anti-Bacterial Agents; Arsenic; Metals, Heavy; Plasmids
PubMed: 36142804
DOI: 10.3390/ijms231810893 -
Future Microbiology Mar 2013Acinetobacter baumannii causes a wide range of severe infections among compromised and injured patients worldwide. The relevance of these infections are, in part, due to... (Review)
Review
Acinetobacter baumannii causes a wide range of severe infections among compromised and injured patients worldwide. The relevance of these infections are, in part, due to the ability of this pathogen to sense and react to environmental and host stress signals, allowing it to persist and disseminate in medical settings and the human host. This review summarizes current knowledge on the roles that environmental and cellular stressors play in the ability of A. baumannii to resist nutrient deprivation, oxidative and nitrosative injury, and even the presence of the commonly used antiseptic ethanol, which could serve as a nutrient- and virulence-enhancing signal rather than just being a convenient disinfectant. Emerging experimental evidence supports the role of some of these responses in the pathogenesis of the infections A. baumannii causes in humans and its capacity to resist antibiotics and host response effectors.
Topics: Acinetobacter baumannii; Drug Resistance, Bacterial; Host-Pathogen Interactions; Humans; Stress, Physiological; Virulence
PubMed: 23464372
DOI: 10.2217/fmb.12.150