ABSTRACT
Urinary tract infections (UTIs) are a major concern in public health. The prevalent uropathogenic bacterium in healthcare settings is Escherichia coli. The increasing rate of antibiotic-resistant strains demands studies to understand E. coli pathogenesis to drive the development of new therapeutic approaches. This study compared the gene expression profile of selected target genes in the prototype uropathogenic E. coli (UPEC) strain CFT073 grown in Luria Bertani (LB), artificial urine (AU), and during adhesion to host bladder cells by semi-quantitative real-time PCR (RT-PCR) assays. AU effectively supported the growth of strain CFT073 as well as other E. coli strains with different lifestyles, thereby confirming the appropriateness of this medium for in vitro models. Unexpectedly, gene expression of strain CFT073 in LB and AU was quite similar; conversely, during the adhesion assay, adhesins and porins were upregulated, while key global regulators were downregulated with respect to lab media. Interestingly, fimH and papGII genes were significantly expressed in all tested conditions. Taken together, these results provide for the first time insights of the metabolic and pathogenic profile of strain CFT073 during the essential phase of host cell adhesion.
Subject(s)
Escherichia coli Infections , Escherichia coli Proteins , Uropathogenic Escherichia coli , Cell Adhesion , Escherichia coli Infections/microbiology , Escherichia coli Proteins/genetics , Escherichia coli Proteins/metabolism , Humans , Uropathogenic Escherichia coli/genetics , Uropathogenic Escherichia coli/metabolism , Virulence/geneticsABSTRACT
Urinary tract infections (UTIs) are among the most common causes of infections in women. Via the fecal-perineal-urethral route, uropathogenic Escherichia coli (UPEC) can cause ascending urinary tract infections, including cystitis and pyelonephritis. These infections re-occur within six months or they account for, at least, three episodes within a year of recurrent UTIs (rUTIs). Long term and continuous antibiotic treatment or prophylaxis should be considered as the last options in rUTIs. Conversely, updated European Association of Urology guidelines recommend non-antimicrobial approaches to prevent rUTIs. Accordingly, several studies reported the efficacy of number of natural molecules in inhibiting UPEC adhesion to bladder cells, restraining bacterial growth, as well as stimulating the host innate immune defenses, and protecting the bladder and the kidney mucosa. Therefore, we propose an "anti-UPEC" diet enriched of foods containing natural compounds that were proven effective against UPEC, such as D-mannose, cranberry extracts and medicinal plants. Being a valuable and safe clinical approach to reduce UTI recurrence and limiting the detrimental effects of long and continuous antibiotic prophylaxis, dietary interventions should be evaluated in future clinical trials.
Subject(s)
Escherichia coli Infections , Urinary Tract Infections , Uropathogenic Escherichia coli , Anti-Bacterial Agents , Escherichia coli Infections/prevention & control , Female , Humans , Urinary Bladder , Urinary Tract Infections/prevention & controlABSTRACT
Urinary tract infections (UTIs) are mainly caused by uropathogenic Escherichia coli (UPEC). Acute and recurrent UTIs are commonly treated with antibiotics, the efficacy of which is limited by the emergence of antibiotic resistant strains. The natural sugar d-mannose is considered as an alternative to antibiotics due to its ability to mask the bacterial adhesin FimH, thereby preventing its binding to urothelial cells. Despite its extensive use, the possibility that d-mannose exerts "antibiotic-like" activity by altering bacterial growth and metabolism or selecting FimH variants has not been investigated yet. To this aim, main bacterial features of the prototype UPEC strain CFT073 treated with d-mannose were analyzed by standard microbiological methods. FimH functionality was analyzed by yeast agglutination and human bladder cell adhesion assays. Our results indicate that high d-mannose concentrations have no effect on bacterial growth and do not interfere with the activity of different antibiotics. d-mannose ranked as the least preferred carbon source to support bacterial metabolism and growth, in comparison with d-glucose, d-fructose, and l-arabinose. Since small glucose amounts are physiologically detectable in urine, we can conclude that the presence of d-mannose is irrelevant for bacterial metabolism. Moreover, d-mannose removal after long-term exposure did not alter FimH's capacity to bind to mannosylated proteins. Overall, our data indicate that d-mannose is a good alternative in the prevention and treatment of UPEC-related UTIs.
Subject(s)
Adhesins, Escherichia coli/metabolism , Escherichia coli Infections/metabolism , Fimbriae Proteins/metabolism , Mannose/pharmacology , Urinary Tract Infections/metabolism , Uropathogenic Escherichia coli/metabolism , Cell Line , Humans , Saccharomyces cerevisiae/metabolismABSTRACT
BACKGROUND: Quantification of intracellular bacteria is fundamental in many areas of cellular and clinical microbiology to study acute and chronic infections. Therefore, rapid, accurate and low-cost methods represent valuable tools in determining bacterial ability to persist and proliferate within eukaryotic cells. RESULTS: Herein, we present the first application of the immunofluorescence In-Cell Western (ICW) assay aimed at quantifying intracellular bacteria in in vitro infection models. The performance of this new approach was evaluated in cell culture infection models using three microorganisms with different lifestyles. Two facultative intracellular bacteria, the fast-growing Shigella flexneri and a persistent strain of Escherichia coli, as well as the obligate intracellular bacterium Chlamydia trachomatis were chosen as bacterial models. The ICW assay was performed in parallel with conventional quantification methods, i.e. colony forming units (CFUs) and inclusion forming units (IFUs). The fluorescence signal intensity values from the ICW assay were highly correlated to CFU/IFUs counting and showed coefficients of determination (R2), ranging from 0,92 to 0,99. CONCLUSIONS: The ICW assay offers several advantages including sensitivity, reproducibility, high speed, operator-independent data acquisition and overtime stability of fluorescence signals. All these features, together with the simplicity in performance, make this assay particularly suitable for high-throughput screening and diagnostic approaches.
Subject(s)
Bacterial Infections/diagnosis , Bacteriological Techniques/methods , Chlamydia trachomatis/growth & development , Escherichia coli/growth & development , Shigella flexneri/growth & development , Cell Line , Chlamydia trachomatis/isolation & purification , Colony Count, Microbial , Escherichia coli/isolation & purification , HeLa Cells , High-Throughput Screening Assays , Humans , Models, Biological , Reproducibility of Results , Shigella flexneri/isolation & purificationABSTRACT
Carbapenem-resistant Acinetobacter baumannii strains cause life-threatening infections due to the lack of therapeutic options. Although the main mechanisms underlying antibiotic-resistance have been extensively studied, the general response to maintain bacterial viability under antibiotic exposure deserves to be fully investigated. Since the periplasmic space contains several proteins with crucial cellular functions, besides carbapenemases, we decided to study the periplasmic proteome of the multidrug-resistant (MDR) A. baumannii AB5075 strain, grown in the absence and presence of imipenem (IMP). Through the proteomic approach, 65 unique periplasmic proteins common in both growth conditions were identified: eight proteins involved in protein fate, response to oxidative stress, energy metabolism, antibiotic-resistance, were differentially expressed. Among them, ABUW_1746 and ABUW_2363 gene products presented the tetratricopeptide repeat motif, mediating protein-protein interactions. The expression switch of these proteins might determine specific protein interactions to better adapt to changing environmental conditions. ABUW_2868, encoding a heat shock protein likely involved in protection against oxidative stress, was upregulated in IMP-exposed bacteria. Accordingly, the addition of periplasmic proteins from A. baumannii cultured with IMP increased bacterial viability in an antioxidant activity assay. Overall, this study provides the first insights about the composition of the periplasmic proteins of a MDR A. baumannii strain, its biological response to IMP and suggests possible new targets to develop alternative antibiotic drugs.
Subject(s)
Acinetobacter baumannii/drug effects , Acinetobacter baumannii/metabolism , Anti-Bacterial Agents/pharmacology , Imipenem/pharmacology , Periplasmic Proteins/metabolism , Acinetobacter Infections/microbiology , Amino Acids/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Dose-Response Relationship, Drug , Drug Resistance, Bacterial , Gene Expression Regulation, Bacterial/drug effects , Lipid Metabolism/drug effects , Microbial Sensitivity Tests , Oxidative Stress , Periplasmic Proteins/genetics , Phenotype , Proteome , Proteomics/methodsABSTRACT
Some Escherichia coli strains of phylogroup B2 harbor a (pks) pathogenicity island that encodes a polyketide-peptide genotoxin called colibactin. It causes DNA double-strand breaks and megalocytosis in eukaryotic cells and it may contribute to cancer development. Study of bacterial community that colonizes the adenomatous polyp lesion, defined as precancerous lesions, could be helpful to assess if such pathogenic bacteria possess a role in the polyp progression to cancer. In this cross-sectional study, a total of 1500 E. coli isolates were obtained from biopsies of patients presenting adenomatous colon polyps, the normal tissues adjacent to the polyp lesion and patients presenting normal mucosa. pks island frequency, phylogenetic grouping, fingerprint genotyping, and virulence gene features of pks positive (pks+) E. coli isolates were performed. We found pks+E. coli strongly colonize two patients presenting polypoid lesions and none were identified in patients presenting normal mucosa. Predominant phylogroups among pks+E. coli isolates were B2, followed by D. Clustering based on fragment profiles of composite analysis, typed the pks+ isolates into 5 major clusters (I-V) and 17 sub-clusters, demonstrating a high level of genetic diversity among them. The most prevalent virulence genes were fimH and fyuA (100%), followed by vat (92%), hra and papA (69%), ibeA (28%), and hlyA (25%). Our results revealed that pks+E. coli can colonize the precancerous lesions, with a high distribution in both the polyp lesions and in normal tissues adjacent to the lesion. The high differences in fingerprinting patterns obtained indicate that pks+E. coli strains were genetically diverse, possibly allowing them to more easily adapt to environmental variations.
Subject(s)
Escherichia coli Proteins/genetics , Escherichia coli/classification , Escherichia coli/genetics , Genetic Variation , Intestinal Polyps/microbiology , Phylogeny , Virulence Factors/genetics , Adhesins, Escherichia coli/genetics , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/pharmacology , Bacterial Toxins/genetics , Biopsy , Cross-Sectional Studies , DNA, Bacterial/genetics , Escherichia coli/isolation & purification , Escherichia coli Infections/microbiology , Fimbriae Proteins/genetics , Genomic Islands , Genotype , Hemolysin Proteins/genetics , Humans , Italy , Membrane Proteins/genetics , Microbial Sensitivity Tests , Middle Aged , Molecular Epidemiology , Peptides/genetics , Polyketides , Receptors, Cell Surface/genetics , VirulenceABSTRACT
Acinetobacter baumannii is a critical opportunistic pathogen associated with nosocomial infections. The high rates of antibiotic-resistance acquisition make most antibiotics ineffective. Thus, new medical countermeasures are urgently needed. Outer membrane proteins (OMPs) are prime candidates for developing novel drug targets and antibacterial strategies. However, there are substantial gaps in our knowledge of A. baumannii OMPs. This study reports the impact of OmpA-like protein on bacterial physiology and virulence in A. baumannii strain AB5075. We found that PsaB (ABUW_0505) negatively correlates to stress tolerance, while ArfA (ABUW_2730) significantly affects bacterial stiffness, cell shape, and cell envelope thickness. Furthermore, we expand our knowledge on YiaD (ABUW_3045), demonstrating structural and virulence roles of this porin, in addition to meropenem resistance. This study provides solid foundations for understanding how uncharacterized OMPs contribute to A. baumannii's physiological and pathological processes, aiding the development of innovative therapeutic strategies against A. baumannii infections.
Subject(s)
Acinetobacter Infections , Acinetobacter baumannii , Anti-Bacterial Agents , Bacterial Outer Membrane Proteins , Porins , Acinetobacter baumannii/pathogenicity , Acinetobacter baumannii/drug effects , Acinetobacter baumannii/physiology , Bacterial Outer Membrane Proteins/metabolism , Bacterial Outer Membrane Proteins/genetics , Virulence , Anti-Bacterial Agents/pharmacology , Porins/metabolism , Porins/genetics , Acinetobacter Infections/microbiology , Acinetobacter Infections/drug therapy , Animals , Drug Resistance, Bacterial , Mice , Microbial Sensitivity Tests , FemaleABSTRACT
BACKGROUND: Urinary tract infections (UTIs) are one of the most common bacterial infections with global expansion. These infections are predominantly caused by uropathogenic Escherichia coli (UPEC). METHODS: Totally, 123 strains of Escherichia coli isolated from UTIs patients, using bacterial culture method were subjected to polymerase chain reactions for detection of various O- serogroups, some urovirulence factors, antibiotic resistance genes and resistance to 13 different antibiotics. RESULTS: According to data, the distribution of O1, O2, O6, O7 and O16 serogroups were 2.43%, besides O22, O75 and O83 serogroups were 1.62%. Furthermore, the distribution of O4, O8, O15, O21 and O25 serogroups were 5.69%, 3.25%, 21.13%, 4.06% and 26.01%, respectively. Overall, the fim virulence gene had the highest (86.17%) while the usp virulence gene had the lowest distributions of virulence genes in UPEC strains isolated from UTIs patients. The vat and sen virulence genes were not detected in any UPEC strains. Totally, aadA1 (52.84%), and qnr (46.34%) were the most prevalent antibiotic resistance genes while the distribution of cat1 (15.44%), cmlA (15.44%) and dfrA1 (21.95%) were the least. Resistance to penicillin (100%) and tetracycline (73.98%) had the highest while resistance to nitrofurantoin (5.69%) and trimethoprim (16.26%) had the lowest frequencies. CONCLUSIONS: This study indicated that the UPEC strains which harbored the high numbers of virulence and antibiotic resistance genes had the high ability to cause diseases that are resistant to most antibiotics. In the current situation, it seems that the administration of penicillin and tetracycline for the treatment of UTIs is vain.
Subject(s)
Drug Resistance, Multiple, Bacterial , Genes, Bacterial , Uropathogenic Escherichia coli/pathogenicity , Virulence Factors/analysis , Disk Diffusion Antimicrobial Tests , Escherichia coli Infections/diagnosis , Escherichia coli Infections/epidemiology , Escherichia coli Proteins/genetics , Humans , Incidence , Iran/epidemiology , Nitrofurantoin/pharmacology , Penicillins/pharmacology , Urinary Tract Infections/diagnosis , Urinary Tract Infections/epidemiology , Urinary Tract Infections/microbiology , Uropathogenic Escherichia coli/classification , Uropathogenic Escherichia coli/drug effects , Uropathogenic Escherichia coli/geneticsABSTRACT
Toll-like receptors (TLRs) serve as the body's first line of defense, recognizing both pathogen-expressed molecules and host-derived molecules released from damaged or dying cells. The wide distribution of different cell types, ranging from epithelial to immune cells, highlights the crucial roles of TLRs in linking innate and adaptive immunity. Upon stimulation, TLRs binding mediates the expression of several adapter proteins and downstream kinases, that lead to the induction of several other signaling molecules such as key pro-inflammatory mediators. Indeed, extraordinary progress in immunobiological research has suggested that TLRs could represent promising targets for the therapeutic intervention of inflammation-associated diseases, autoimmune diseases, microbial infections as well as human cancers. So far, for the prevention and possible treatment of inflammatory diseases, various TLR antagonists/inhibitors have shown to be efficacious at several stages from pre-clinical evaluation to clinical trials. Therefore, the fascinating role of TLRs in modulating the human immune responses at innate as well as adaptive levels directed the scientists to opt for these immune sensor proteins as suitable targets for developing chemotherapeutics and immunotherapeutics against cancer. Hitherto, several TLR-targeting small molecules (e.g., Pam3CSK4, Poly (I:C), Poly (A:U)), chemical compounds, phytocompounds (e.g., Curcumin), peptides, and antibodies have been found to confer protection against several types of cancers. However, administration of inappropriate doses of such TLR-modulating therapeutics or a wrong infusion administration is reported to induce detrimental outcomes. This review summarizes the current findings on the molecular and structural biology of TLRs and gives an overview of the potency and promises of TLR-directed therapeutic strategies against cancers by discussing the findings from established and pipeline discoveries.
Subject(s)
Immunity, Innate , Neoplasms , Humans , Toll-Like Receptors/metabolism , Neoplasms/drug therapy , Signal Transduction , Adaptive ImmunityABSTRACT
IMPORTANCE: In this paper, we demonstrated that apyrase is released within the host cell cytoplasm during infection to target the intracellular ATP pool. By degrading intracellular ATP, apyrase contributes to prevent caspases activation, thereby inhibiting the activation of pyroptosis in infected cells. Our results show, for the first time, that apyrase is involved in the modulation of host cell survival, thereby aiding this pathogen to dampen the inflammatory response. This work adds a further piece to the puzzle of Shigella pathogenesis. Due to its increased spread worldwide, prevention and controlling strategies are urgently needed. Overall, this study highlighted apyrase as a suitable target for an anti-virulence therapy to tackle this pathogen.
Subject(s)
Bacterial Proteins , Virulence Factors , Shigella flexneri , Apyrase , Eukaryotic Cells , Adenosine TriphosphateABSTRACT
Selective antiadhesion antagonists of Uropathogenic Escherichia coli (UPEC) type-1 Fimbrial adhesin (FimH) are attractive alternatives for antibiotic therapies and prophylaxes against acute or recurrent urinary tract infections (UTIs) caused by UPECs. A rational small library of FimH antagonists based on previously described C-linked allyl α-D-mannopyranoside was synthesized using Heck cross-coupling reaction using a series of iodoaryl derivatives. This work reports two new members of FimH antagonist amongst the above family with sub nanomolar affinity. The resulting hydrophobic aglycones, including constrained alkene and aryl groups, were designed to provide additional favorable binding interactions with the so-called FimH "tyrosine gate". The newly synthesized C-linked glycomimetic antagonists, having a hydrolytically stable anomeric linkage, exhibited improved binding when compared to previously published analogs, as demonstrated by affinity measurement through interactions by FimH lectin. The crystal structure of FimH co-crystallized with one of the nanomolar antagonists revealed the binding mode of this inhibitor into the active site of the tyrosine gate. In addition, selected mannopyranoside constructs neither affected bacterial growth or cell viability nor interfered with antibiotic activity. C-linked mannoside antagonists were effective in decreasing bacterial adhesion to human bladder epithelial cells (HTB-9). Therefore, these molecules constituted additional therapeutic candidates' worth further development in the search for potent anti-adhesive drugs against infections caused by UPEC.
ABSTRACT
Bacterial small RNAs (sRNAs) research has accelerated over the past decade, boosted by advances in RNA-seq technologies and methodologies for capturing both protein-RNA and RNA-RNA interactions. The emerging picture is that these regulatory sRNAs play important roles in controlling complex physiological processes and are required to survive the antimicrobial challenge. In recent years, the RNA content of OMVs/EVs has also gained increasing attention, particularly in the context of infection. Secreted RNAs from several bacterial pathogens have been characterized but the exact mechanisms promoting pathogenicity remain elusive. In this review, we briefly discuss how secreted sRNAs interact with targets in infected cells, thus representing a novel perspective of host cell manipulation during bacterial infection. During the last decade, Acinetobacter baumannii became clinically relevant emerging pathogens responsible for nosocomial and community-acquired infections. Therefore, we also summarize recent findings of regulation by sRNAs in A. baumannii and discuss how this emerging bacterium utilizes many of these sRNAs to adapt to its niche and become successful human pathogen.
ABSTRACT
Development of an optimized protocol to produce sufficient functional human insulin-producing islet-like cluster is important as a potential therapeutic strategy for diabetes as well as in vitro studies. Here, we described a stepwise protocol for differentiation of the human induced pluripotent stem cell line (R1-hiPSC1) into the islet-like cluster using several growth factors and small molecules. Therefore, various differentiation steps have been adopted to maximize mimicking of developmental processes in order to form functional islet like cluster. The differentiation protocol enables us to generate 3D islet-like clusters with highly viable cells, which are insulin producer and glucose responsive. Transcriptome analysis of transcription factors and functional genes revealed high coordination between gene expressions and resembling to those reported during natural development of islet cell. This coordination was further confirmed by hierarchical clustering of genes during differentiation. Furthermore, the islet-like clusters were enriched with insulin producing cells and formed glucose responsiveness behavior upon stimulation with glucose. Our protocol provides a robust platform and well-behaved model for additional developmental studies and shed light our clusters as a good candidate for in vitro model. Further studies are needed to assess the hormonal content of this cluster as well as transplantation into the animal model.
Subject(s)
Cell Culture Techniques, Three Dimensional , Cell Differentiation , Induced Pluripotent Stem Cells , Pluripotent Stem Cells , Animals , Cell Culture Techniques, Three Dimensional/methods , Glucose/metabolism , Humans , Induced Pluripotent Stem Cells/metabolism , Insulin/metabolism , Insulin-Secreting Cells/metabolism , Islets of Langerhans/metabolism , Pluripotent Stem Cells/metabolism , Transcription Factors/metabolismABSTRACT
In recent years, the clinical use of extracellular miRNAs as potential biomarkers of disease has increasingly emerged as a new and powerful tool. Serum, urine, saliva and stool contain miRNAs that can exert regulatory effects not only in surrounding epithelial cells but can also modulate bacterial gene expression, thus acting as a "master regulator" of many biological processes. We think that in order to have a holistic picture of the health status of an individual, we have to consider comprehensively many "omics" data, such as miRNAs profiling form different parts of the body and their interactions with cells and bacteria. Moreover, Artificial Intelligence (AI) and Machine Learning (ML) algorithms coupled to other multiomics data (i.e., big data) could help researchers to classify better the patient's molecular characteristics and drive clinicians to identify personalized therapeutic strategies. Here, we highlight how the integration of "multiomic" data (i.e., miRNAs profiling and microbiota signature) with other omics (i.e., metabolomics, exposomics) analyzed by AI algorithms could improve the diagnostic and prognostic potential of specific biomarkers of disease.
ABSTRACT
Celiac disease (CD) is a multifactorial autoimmune enteropathy with a prevalence greater than 1% in the pediatric population. The only therapy for CD patients is a strict gluten-free diet (GFD). Gluten-free food contamination by other cereals during packaging and cooking or accidental ingestion of gluten may cause several intestinal and extraintestinal symptoms in CD patients. Therefore, the monitoring of gluten contamination in food and assessing the level of ingested gluten by analytical biomarkers has been of great interest in recent years. To this aim, small gluten immunogenic peptides (GIPs) obtained by the hydrolysis of gluten and present in urine and feces have been studied as biomarkers of gluten intake and to monitor adherence to GFD by CD patients. More recently, the use of circulating, fecal and urinary miRNAs has emerged as a novel diagnostic tool that can be potentially applied to assess adherence to GFD. Moreover, the presence of GIPs and miRNAs in both feces and urine suggests a similar excretion modality and the possibility of using urinary miRNAs, similarly to GIPs, as potential biomarkers of GFD in CD patients.
ABSTRACT
Background: Anisakis spp. third-stage larvae (L3) are the causative agents of human zoonosis called anisakiasis. The accidental ingestion of L3 can cause acute and chronic inflammation at the gastric, intestinal, or ectopic levels. Despite its relevance in public health, studies on pathogenetic mechanisms and parasite-human interplay are scarce. The aim of this study was to investigate the human inflammatory response to different Anisakis vehicles of pathogenicity. Methods: Human colorectal adenocarcinoma (Caco-2) cells were exposed to Anisakis L3 (the initial contact with the host), extracellular vesicles (EVs, Anisakis-host communication), and crude extract (CE, the larval dying). The protein quantity and gene expression of two pro-inflammatory cytokines (IL-6 and IL-8) were investigated using an ELISA test (6 h and 24 h) and a qReal-Time PCR (1 h, 6 h, and 24 h), respectively. Results: The L3 and EVs induced a downregulation in both the Il-6 and Il-8 gene expression and protein quantity. On the contrary, the CE stimulated IL-6 gene expression and its protein release, not affecting IL-8. Conclusions: The Caco-2 cells seemed to not react to the exposure to the L3 and EVs, suggesting a parasite's immunomodulating action to remain alive in an inhospitable niche. Conversely, the dying larva (CE) could induce strong activation of the immune strategy of the host that, in vivo, would lead to parasite expulsion, eosinophilia, and/or granuloma formation.
ABSTRACT
In recent decades, Acinetobacter baumannii emerged as a major infective menace in healthcare settings due to scarce therapeutic options to treat infections. Therefore, undertaking genome comparison analyses of multi-resistant A. baumannii strains could aid the identification of key bacterial determinants to develop innovative anti-virulence approaches. Following genome sequencing, we performed a molecular characterization of key genes and genomic comparison of two A. baumannii strains, #36 and #150, with selected reference genomes. Despite a different antibiotic resistance gene content, the analyzed strains showed a very similar antibiogram profile. Interestingly, the lack of some important virulence determinants (i.e., bap, ata and omp33-36) did not abrogate their adhesive abilities to abiotic and biotic surfaces, as reported before; indeed, strains retained these capacities, although to a different extent, suggesting the presence of distinct vicarious genes. Conversely, secretion systems, lipopolysaccharide (LPS), capsule and iron acquisition systems were highly similar to A. baumannii reference strains. Overall, our analyses increased our knowledge on A. baumannii genomic content and organization as well as the genomic events occurring in nosocomial isolates to better fit into changing healthcare environments.
Subject(s)
Acinetobacter Infections , Acinetobacter baumannii , Acinetobacter Infections/drug therapy , Acinetobacter Infections/microbiology , Acinetobacter baumannii/genetics , Anti-Bacterial Agents/pharmacology , Anti-Bacterial Agents/therapeutic use , Drug Resistance, Bacterial/genetics , Drug Resistance, Multiple, Bacterial/genetics , Genetic Variation , Humans , Microbial Sensitivity Tests , Virulence/geneticsABSTRACT
Interleukins (ILs)-which are important members of cytokines-consist of a vast group of molecules, including a wide range of immune mediators that contribute to the immunological responses of many cells and tissues. ILs are immune-glycoproteins, which directly contribute to the growth, activation, adhesion, differentiation, migration, proliferation, and maturation of immune cells; and subsequently, they are involved in the pro and anti-inflammatory responses of the body, by their interaction with a wide range of receptors. Due to the importance of immune system in different organisms, the genes belonging to immune elements, such as ILs, have been studied vigorously. The results of recent investigations showed that the genes pertaining to the immune system undergo progressive evolution with a constant rate. The occurrence of any mutation or polymorphism in IL genes may result in substantial changes in their biology and function and may be associated with a wide range of diseases and disorders. Among these abnormalities, single nucleotide polymorphisms (SNPs) can represent as important disruptive factors. The present review aims at concisely summarizing the current knowledge available on the occurrence, properties, role, and biological consequences of SNPs within the IL-1 family members.
Subject(s)
Cytokines , Interleukin-1 , Cytokines/genetics , Interleukin-1/genetics , Interleukins/genetics , Polymorphism, Single NucleotideABSTRACT
Acinetobacter baumannii is regarded as a life-threatening pathogen associated with community-acquired and nosocomial infections, mainly pneumonia. The rise in the number of A. baumannii antibiotic-resistant strains reduces effective therapies and increases mortality. Bacterial comparative genomic studies have unraveled the innate and acquired virulence factors of A. baumannii. These virulence factors are involved in antibiotic resistance, environmental persistence, host-pathogen interactions, and immune evasion. Studies on host-pathogen interactions revealed that A. baumannii evolved different mechanisms to adhere to in order to invade host respiratory cells as well as evade the host immune system. In this review, we discuss current data on A. baumannii genetic features and virulence factors. An emphasis is given to the players in host-pathogen interaction in the respiratory tract. In addition, we report recent investigations into host defense systems using in vitro and in vivo models, providing new insights into the innate immune response to A. baumannii infections. Increasing our knowledge of A. baumannii pathogenesis may help the development of novel therapeutic strategies based on anti-adhesive, anti-virulence, and anti-cell to cell signaling pathways drugs.
ABSTRACT
Bacterial biofilms are a serious public-health problem worldwide. In recent years, the rates of antibiotic-resistant Gram-negative bacteria associated with biofilm-forming activity have increased worrisomely, particularly among healthcare-associated pathogens. Acinetobacter baumannii is a critically opportunistic pathogen, due to the high rates of antibiotic resistant strains causing healthcare-acquired infections (HAIs). The clinical isolates of A. baumannii can form biofilms on both biotic and abiotic surfaces; hospital settings and medical devices are the ideal environments for A. baumannii biofilms, thereby representing the main source of patient infections. However, the paucity of therapeutic options poses major concerns for human health infections caused by A. baumannii strains. The increasing number of multidrug-resistant A. baumannii biofilm-forming isolates in association with the limited number of biofilm-eradicating treatments intensify the need for effective antibiofilm approaches. This review discusses the mechanisms used by this opportunistic pathogen to form biofilms, describes their clinical impact, and summarizes the current and emerging treatment options available, both to prevent their formation and to disrupt preformed A. baumannii biofilms.