Pathogen Acinetobacter Baumannii Research Articles

Comparative study of phenotypic and genotypic expression of virulence factors in colonizing and pathogenic carbapenem resistant Acinetobacter baumannii (CRAB)

Carbapenem resistant Acinetobacter baumannii has evolved as the most troublesome microorganism with multiple virulence factors. Biofilm formation, porins, micronutrient capturing mechanism and quorum sensing, provide protection against desiccation, host-pathogen killing and enhance its persistence. The conservation of these factors between colonizing and pathogenic carbapenem resistant A. baumannii has been barely investigated. We studied biofilm formation, desiccation survival, motility and hemolysis in pathogenic carbapenem resistant A. baumannii and colonizer carbapenem resistant A. baumannii from the hospital environment. The virulent genes pgaA, csuE, bap, ompA, abaI, pilA and bauA were detected by simplex-PCR and Quantitative Real-Time PCR was done for expressional studies. In-vivo survival percentage was studied by Galleria mellonella (wax moth) killing assay. Phenotypic characterization revealed that the biofilm formation and desiccation survival proportion was significantly higher in colonizer carbapenem resistant A. baumannii (p < 0.05). Twitching motility was found comparable (mean 0.5 to 1.5 cm). Surface associated motility varied widely. None showed hemolysis. The csuE, bap, ompA, abaI, pilA and bauA genes were detected in almost all the pathogenic and colonizer carbapenem resistant A. baumannii isolates while none harboured pgaA gene. The expression of bap, ompA and bauA gene was found significantly higher in pathogenic carbapenem resistant A. baumannii while expression of csuE and abaI gene was comparable in both. Overexpression of pilA gene was seen in those with higher surface associated motility. Pathogenic carbapenem resistant A. baumannii showed significantly higher pathogenicity in-vivo, as 100% of larvae died on 4th day post-infection. In conclusion high level expression of outer membrane proteins (ompA) and siderophores is significantly associated with the pathogenicity in carbapenem resistant A. baumannii isolated from infections, which can be a differentiating point from the colonizers.Clinical TrialNot Applicable

Theoretical and Pharmacological Investigations of Phenylthiazol-2, 4 Dihydroxybenzaldehyde Condensed Schiff Base

The ability of thiazole derivatives to alter the activity of numerous metabolic enzymes suggests that they have promising therapeutic applications. Their antimicrobial, antifungal, anti-inflammatory, antioxidant, and antiproliferative properties were also established. The Schiff base, which was formed by combining 2, 4-dihydrxy benzaldehyde with phenyl thiazole amine, was studied using UV, FTIR, 1H, and 13C-NMR. The significant absorption (283 nm) and vibrational peaks at 1625 cm-1 were observed for the imine group. The compound was confirmed by the presence of a free proton and carbon peak following the aromatic peaks. The derivative underwent theoretical and biological evaluations, such as antibacterial, inhibition of alpha amylase, and DPPH scavenging assays. Using an online server, QSAR parameters were predicted for the synthesised molecule and compared with drug likeness using Lipinski five rules. The experimental results are compared with theoretical DFT and docking outcomes. The DFT results revealed the compound's reactivity and decreased hardness feature. Docking interaction score ranges from -5.2 to -11.2 kcal/mol. The antimicrobial activity against the pathogens Acinetobacter baumannii, Methicillin-resistant Staphylococcus aureus, and Staphylococcus aureus was observed between 12 and 15 mm inhibition zone with the minimum inhibition concentration maximum of 150±0.28 µg/mL. Likely, antidiabetic and antioxidant outcomes showed the effective concentration from 428.73±0.32 to 590.36± 0.34 µg/mL. There was excellent agreement with theoretical QSAR and docking values in the prepared Schiff base.

Antimicrobial activity of iron-depriving pyoverdines against human opportunistic pathogens

The global rise of antibiotic resistance calls for new drugs against bacterial pathogens. A common approach is to search for natural compounds deployed by microbes to inhibit competitors. Here, we show that the iron-chelating pyoverdines, siderophores produced by environmental Pseudomonas spp., have strong antibacterial properties by inducing iron starvation and growth arrest in pathogens. A screen of 320 natural Pseudomonas isolates used against 12 human pathogens uncovered several pyoverdines with particularly high antibacterial properties and distinct chemical characteristics. The most potent pyoverdine effectively reduced growth of the pathogens Acinetobacter baumannii, Klebsiella pneumoniae, and Staphylococcus aureus in a concentration- and iron-dependent manner. Pyoverdine increased survival of infected Galleria mellonella host larvae and showed low toxicity for the host, mammalian cell lines, and erythrocytes. Furthermore, experimental evolution of pathogens combined with whole-genome sequencing revealed limited resistance evolution compared to an antibiotic. Thus, pyoverdines from environmental strains have the potential to become a new class of sustainable antibacterials against specific human pathogens.

Structure of the K58 capsular polysaccharide produced by Acinetobacter baumannii isolate MRSN 31468 includes Pse5Ac7Ac that is 4-O-acetylated by a phage-encoded acetyltransferase

Capsular polysaccharide (CPS), a heteropolymeric carbohydrate structure present on the cell surface of most isolates of the bacterial pathogen Acinetobacter baumannii, is a major virulence determinant. Here, the CPS produced by A. baumannii MRSN 31468, which carries the KL58 CPS biosynthesis locus, was studied by sugar analysis, one- and two-dimensional 1H and 13C NMR spectroscopy. The structure was found to consist of a repeating tetrasaccharide K-unit that includes glucose (d-Glcp), galactose (d-Galp), N-acetyl-galactosamine (d-GalpNAc), and 5,7-diacetamido-3,5,7,9-tetradeoxy-l-glycero-l-manno-non-2-ulosonic acid (5,7-di-N-acetylpseudaminic acid; Pse5Ac7Ac). The CPS has a branched repeating unit with the disaccharide →3)-β-d-Glc-(1→3)-β-d-GalNAc-(1→ as the mainchain and O-6 of the Glc unit substituted with the disaccharide β-Pse5Ac7Ac-(2→6)-α-d-Gal, and Pse5Ac7Ac is partially acetylated at O-4. The presence of Pse5Ac7Ac in the K58 structure is consistent with the presence of psaA-F genes in KL58, which are responsible for Pse5Ac7Ac synthesis. 4-O-acetylation of Pse5Ac7Ac was traced to an acetyltransferase, Atr44, which was found to be closely related to Atr29 that similarly decorates Pse5Ac7Ac with 4OAc in the K46-type CPS. Atr44 like Atr29 is encoded by a gene found in a prophage. The K58 CPS produced by MRSN 31468 did not include the 8-epimer of Pse5Ac7Ac (5,7-di-N-acetyl-8-epipseudaminic acid; 8ePse5Ac7Ac) found in the closely related CPS from BAL062 that also carries KL58. Hence, the gene(s) for conversion of Pse5Ac7Ac to 8ePse5Ac7Ac must lie elsewhere.

Antimicrobial Resistance Profile of Zoonotic Clinically Relevant WHO Priority Pathogens.

The World Health Organization announced critically important bacterial and fungal pathogens displaying alarming levels of antimicrobial resistance, which currently represent difficult-to-treat cases of morbidity. Within this grouping, the ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) are causative of significant morbidity and mortality. Studies described herein demonstrate the presence of critically important fungal and ESKAPE bacterial species in companion animals which are zoonotic in nature. The relationship between the environment, animals, and human infectious disease has long been recognized as part of One Health. This research investigates the resistance patterns of isolated zoonotic pathogens using recognized in vitro methodologies, namely disk diffusion, minimum inhibitory concentration testing, and genetic screening. Antibiotic susceptibility testing and gene analysis demonstrated an association between multi-drug resistance and extended beta spectrum lactamase production in critical-priority bacteria. Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa exhibit great levels of multi-drug resistance. Fungal isolates demonstrated high levels of resistance, with Amphotericin B proving the most effective antifungal agent investigated. The level of antimicrobial resistance present in clinically relevant bacterial and fungal pathogens isolated from animal cases of morbidity in this study is alarming. In conclusion, this study shows that animals can act as a reservoir facilitating the transmission of antibiotic-resistant pathogens and genes zoonotically.

Expanding the Substrate Selectivity of the Fimsbactin Biosynthetic Adenylation Domain, FbsH.

Nonribosomal peptide synthetases (NRPSs) produce diverse natural products including siderophores, chelating agents that many pathogenic bacteria produce to survive in low iron conditions. Engineering NRPSs to produce diverse siderophore analogs could lead to the generation of novel antibiotics and imaging agents that take advantage of this unique iron uptake system in bacteria. The highly pathogenic and antibiotic-resistant bacteria Acinetobacter baumannii produces fimsbactin, an unusual branched siderophore with iron-binding catechol groups bound to a serine or threonine side chain. To explore the substrate promiscuity of the assembly line enzymes, we report a structure-guided investigation of the stand-alone aryl adenylation enzyme FbsH. We report structures bound to its native substrate 2,3-dihydroxybenzoic acid (DHB) as well as an inhibitor that mimics the adenylate intermediate. We produced enzyme variants with an expanded binding pocket that are more tolerant for analogs containing a DHB C4 modification. Wild-type and mutant enzymes were then used in an in vitro reconstitution analysis to assess the production of analogs of the final product as well as several early stage intermediates. This analysis shows that some altered substrates progress down the fimsbactin assembly line to the downstream domains. However, analogs from alternate building blocks are produced at lower levels, indicating that selectivity exists in the downstream catalytic domains. These findings expand the substrate scope of producing condensation products between serine and aryl acids and identify the bottlenecks for chemoenzymatic production of fimsbactin analogs.

Cryo-EM reveals transition states of the Acinetobacter baumannii F1-ATPase rotary subunits γ and ε, unveiling novel compound targets.

Priority 1: critical WHO pathogen Acinetobacter baumannii depends on ATP synthesis and ATP:ADP homeostasis and its bifunctional F1FO-ATP synthase. While synthesizing ATP, it regulates ATP cleavage by its inhibitory ε subunit to prevent wasteful ATP consumption. We determined cryo-electron microscopy structures of the ATPase active A. baumannii F1-αßγεΔ134-139 mutant in four distinct conformational states, revealing four transition states and structural transformation of the ε's C-terminal domain, forming the switch of an ATP hydrolysis off- and an ATP synthesis on-state based. These alterations go in concert with altered motions and interactions in the catalytic- and rotary subunits of this engine. These A. baumannii interacting sites provide novel pathogen-specific targets for inhibitors, with the aim of ATP depletion and/or ATP synthesis and growth inhibition. Furthermore, the presented diversity to other bacterial F-ATP synthases extends the view of structural elements regulating such a catalyst.

Amino acid competition shapes Acinetobacter baumannii gut carriage.

Antimicrobial resistance is an urgent threat to human health. Asymptomatic colonization is often critical for persistence of antimicrobial-resistant pathogens. Gut colonization by the antimicrobial-resistant priority pathogen Acinetobacter baumannii is associated with increased risk of clinical infection. Ecological factors shaping A. baumannii gut colonization remain unclear. Here we show that A. baumannii and other pathogenic Acinetobacter evolved to utilize the amino acid ornithine, a non-preferred carbon source. A. baumannii utilizes ornithine to compete with the resident microbiota and persist in the gut in mice. Supplemental dietary ornithine promotes long-term fecal shedding of A. baumannii. By contrast, supplementation of a preferred carbon source-monosodium glutamate (MSG)-abolishes the requirement for A. baumannii ornithine catabolism. Additionally, we report evidence for diet promoting A. baumannii gut carriage in humans. Together, these results highlight that evolution of ornithine catabolism allows A. baumannii to compete with the microbiota in the gut, a reservoir for pathogen spread.

Deciphering the inhibitory mechanism of antimicrobial peptide pexiganan conjugated with sodium-alginate chitosan-cholesterol nanoparticle against the opportunistic pathogen Acinetobacter baumannii

The emergence of antibiotic resistance is one of the most challenging problems of modern times as the armory of conventional antibiotics is quickly exhausting due to the rapid rise of resistance in pathogenic microorganisms. Acinetobacter baumannii, a potential member of ESKAPE group of bacteria, has a great deal of clinical importance causing severe nosocomial infections which often become life-threatening. According to the World Health Organization (WHO), antimicrobial resistance accounts for 2–3 million deaths every year across the world. Since the pathogen has the remarkable ability to acquire or upregulate various resistant determinants in the form of secreting of β-lactamase, aminoglycoside modifying enzymes, uplifting the function of efflux pumps or altering the target sites of different antibiotics; conventional antibiotic therapy often falls short to eradicate the infection. As a possible solution, the application of alternative therapy is therefore the need of the hour. Here we emphasize potentiating the antimicrobial efficacy of pexiganan, a well-known antimicrobial peptide against Gram-negative bacteria. Conjugation with nanoparticles composed of sodium-alginate and chitosan-cholesterol has increased the antimicrobial effect of the peptide on this opportunist pathogen. The evaluation of the bactericidal analysis and minimum inhibitory concentration indicates this nanocomposite can kill the bacteria at a very low concentration (3 μg/ml). When applied to the bacterial biofilm, the key factor for producing recalcitrant infection; our synthesized complex could effectively reduce the biomass in a dose-dependent manner. Later we enfold the mechanism of killing by measuring oxidative stress, cell membrane perforation by biochemical analysis. Our analysis indicates this unique nanocomposite can bypass the need of antibiotic treatment by its pore-forming ability on bacterial membrane. The nominal in-vivo toxicity and non-specific mode of action make it an interesting candidate for future therapeutics.

‘GGFGGQ’ repeats in Hfq of Acinetobacter baumannii are essential for nutrient utilization and virulence

The nosocomial pathogen Acinetobacter baumannii is known for causing lung and soft tissue infections in immunocompromised hosts. Its ability to adapt to various environments through post-transcriptional gene regulation is key to its success. Central to this regulation is the RNA chaperone Hfq, which facilitates interactions between mRNA targets and their small RNA partners through a Sm-core domain. Notably, the A.baumannii Hfq protein has a uniquely long C-terminal domain with "GGFGGQ" amino acid repeats and an acidic amino acid-rich C-terminal tip (C-tip). Previous research has shown the importance of the intact C-terminal domain for Hfq's functionality. Given the significance of the C-tip in Escherichia coli Hfq, we examined the pathophysiological roles of the redundant 'GGFGGQ' repeats along with the C-tip of A.baumannii Hfq. We constructed several variations of Hfq protein with fewer 'GGFGGQ' repeats while preserving the C-tip and variants with altered C-tip amino acid composition. We then studied their RNA interaction abilities and assessed the pathophysiological fitness and virulence of genome-complemented A.baumannii mutants. Our findings reveal that the redundancy of the 'GGFGGQ' repeats is crucial for Hfq's role in pathophysiological fitness and negatively impacts A.baumannii's virulence in a murine lung infection model. In addition, C-tip mutants exhibited a negative effect on both fitness and virulence, however, to a lesser extent than the other variants. These results underscore the importance of 'GGFGGQ' redundancy and acidic residues in Hfq's ribo-regulation and autoregulation, suggesting their critical role in establishing regulatory networks.

Structure of a Rhs effector clade domain provides mechanistic insights into type VI secretion system toxin delivery

The type VI secretion system (T6SS) is a molecular machine utilised by many Gram-negative bacteria to deliver antibacterial toxins into adjacent cells. Here we present the structure of Tse15, a T6SS Rhs effector from the nosocomial pathogen Acinetobacter baumannii. Tse15 forms a triple layered β-cocoon Rhs domain with an N-terminal α-helical clade domain and an unfolded C-terminal toxin domain inside the Rhs cage. Tse15 is cleaved into three domains, through independent auto-cleavage events involving aspartyl protease activity for toxin self-cleavage and a nucleophilic glutamic acid for N-terminal clade cleavage. Proteomic analyses identified that significantly more peptides from the N-terminal clade and toxin domains were secreted than from the Rhs cage, suggesting toxin delivery often occurs without the cage. We propose the clade domain acts as an internal chaperone to mediate toxin tethering to the T6SS machinery. Conservation of the clade domain in other Gram-negative bacteria suggests this may be a common mechanism for delivery.

Rapid design of combination antimicrobial therapy against Acinetobacter baumannii

Treatment of serious bacterial infections with antimicrobial agents, such as antibiotics, is a major clinical challenge, because of growing bacterial resistance to multiple agents. Combination therapy (i.e. combined dosing of more than one agent) is often used for the purpose, but its systematic design remains a challenge. To address this, we recently reported a method to mathematically model bacterial response to antimicrobial agents, and to use this model for systematic design of clinically relevant combination therapy. The method relies on (a) longitudinal data of bacterial load, estimated from optical density measurements during time-kill experiments in an automated instrument, and (b) use of these data to fit a mathematical model for combination therapy design. In this work, we studied an application of the proposed method to (a) an important bacterial pathogen (Acinetobacter baumannii) and (b) two cases of antibiotic combinations (ceftazidime / amikacin and ceftazidime / avibactam) in synchronous and asynchronous dosing, not otherwise studied to date. Following the proposed method, optical density based data of bacterial load under antibiotic exposure for 20 h were used to calibrate the mathematical model and subsequently predict outcomes of various dosing regimens with clinically relevant pharmacokinetics. Representative predictions by the mathematical model were tested in vitro in a hollow fiber infection model over 120 h. Test outcomes validated these predictions. Collectively, this study both provides guidance for design of A. baumannii infection treatments with the agents studied and underscores the broader applicability of the proposed method for design of clinically relevant combination therapy.

Impact of ESKAPE Pathogens on Bacteremia: A Three-Year Surveillance Study at a Major Hospital in Southern Italy.

ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pose a serious public health threat as they are resistant to multiple antimicrobial agents. Bloodstream infections (BSIs) caused by ESKAPE bacteria have high mortality rates due to the limited availability of effective antimicrobials. This study aimed to evaluate the prevalence and susceptibility of ESKAPE pathogens causing BSIs over three years in a large tertiary hospital in Salerno. Conducted at the Clinical Microbiology Laboratory of San Giovanni di Dio e ''Ruggi D'Aragona'' Hospital from January 2020 to December 2022, blood culture samples from different departments were incubated in the BD BACTEC™ system for 5 days. Species identification was performed using MALDI-TOF MS, and antimicrobial resistance patterns were determined by the VITEK2 system. Out of 3197 species isolated from positive blood cultures, 38.7% were ESKAPE bacteria. Of these, 59.9% were found in blood culture samples taken from men, and the most affected age group was those aged >60 years. (70.6%). Staphylococcus aureus was the main BSI pathogen (26.3%), followed by Klebsiella pneumoniae (15.8%). Significant resistance rates were found, including 35% of Staphylococcus aureus being resistant to oxacillin and over 90% of Acinetobacter baumannii being resistant to carbapenems. These results highlight the urgent need for antimicrobial stewardship programs to prevent incurable infections.

Manipulation of natural transformation by AbaR-type islands promotes fixation of antibiotic resistance in Acinetobacter baumannii

The opportunistic pathogen Acinetobacter baumannii, carries variants of A. baumannii resistance islands (AbaR)-type genomic islands conferring multidrug resistance. Their pervasiveness in the species has remained enigmatic. The dissemination of AbaRs is intricately linked to their horizontal transfer via natural transformation, a process through which bacteria can import and recombine exogenous DNA, effecting allelic recombination, genetic acquisition, and deletion. In experimental populations of the closely related pathogenic Acinetobacter nosocomialis, we quantified the rates at which these natural transformation events occur between individuals. When integrated into a model of population dynamics, they lead to the swift removal of AbaRs from the population, contrasting with the high prevalence of AbaRs in genomes. Yet, genomic analyses show that nearly all AbaRs specifically disrupt comM, a gene encoding a helicase critical for natural transformation. We found that such disruption impedes gene acquisition, and deletion, while moderately impacting acquisition of single nucleotide polymorphism. A mathematical evolutionary model demonstrates that AbaRs inserted into comM gain a selective advantage over AbaRs inserted in sites that do not inhibit or completely inhibit transformation, in line with the genomic observations. The persistence of AbaRs can be ascribed to their integration into a specific gene, diminishing the likelihood of their removal from the bacterial genome. This integration preserves the acquisition and elimination of alleles, enabling the host bacterium-and thus its AbaR-to adapt to unpredictable environments and persist over the long term. This work underscores how manipulation of natural transformation by mobile genetic elements can drive the prevalence of multidrug resistance.

Optimization of the Diagnosis of Central Nervous System Infections in Vietnamese Hospitals: Results From a Retrospective Multicenter Study.

Central nervous system infections pose significant health challenges, particularly in low- and middle-income countries, because of high morbidity and mortality rates. Rapid and accurate diagnosis is essential for effective treatment to prevent adverse outcomes. Traditional culture-based diagnostics are often slow and lack specificity. This study evaluates the BioFire FilmArray Meningitis/Encephalitis (FAME) Panel against standard diagnostics in Vietnam to assess its clinical impact and suitability for local epidemiology. We conducted a prospective study involving 330 patients with suspected central nervous system infections at 4 hospitals in northern Vietnam from July 2022 to April 2023. Cerebrospinal fluid samples were analyzed using routine culture methods and FAME. We compared pathogen detection rates and assessed the potential clinical impact of FAME results on patient management. Of the 330 cerebrospinal fluid specimens, 64 (19%) were positive by either conventional diagnostics (n = 48) and/or FAME (n = 33). The agreement between FAME and conventional diagnostics was 87%. Key pathogens Mycobacterium tuberculosis (n = 7), Klebsiella pneumoniae (n = 5), Streptococcus suis (n = 5), Epstein-Barr virus (n = 3), Acinetobacter baumannii (n = 1), and Trichosporon asahii (n = 1) were not detected by FAME. Classical meningitis parameter clinical symptoms, altered glucose, protein, and pleocytosis were good predictors of FAME positivity, indicating their utility in optimizing local diagnostic algorithms. FAME complements traditional diagnostics by offering rapid and broad pathogen detection, crucial for timely and appropriate therapy. However, its effectiveness varies with local epidemiology, and it should not replace conventional methods entirely. Tailoring diagnostic panels to regional pathogen prevalence is recommended to enhance diagnostic accuracy and clinical outcomes in low- and middle-income countries.

Vaccines and monoclonal antibodies to prevent healthcare-associated bacterial infections.

SUMMARYHealthcare-associated infections (HAIs) represent a burden for public health with a high prevalence and high death rates associated with them. Pathogens with a high potential for antimicrobial resistance, such as ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species) and Clostridioides difficile, are responsible for most HAIs. Despite the implementation of infection prevention and control intervention, globally, HAIs prevalence is stable and they are mainly due to endogenous pathogens. It is undeniable that complementary to infection prevention and control measures, prophylactic approaches by active or passive immunization are needed. Specific groups at-risk (elderly people, chronic condition as immunocompromised) and also healthcare workers are key targets. Medical procedures and specific interventions are known to be at risk of HAIs, in addition to hospital environmental exposure. Vaccines or monoclonal antibodies can be seen as attractive preventive approaches for HAIs. In this review, we present an overview of the vaccines and monoclonal antibodies in clinical development for prevention of the major bacterial HAIs pathogens. Based on the current state of knowledge, we look at the challenges and future perspectives to improve prevention by these means.

Antibacterial Activity and Prebiotic Properties of Six Types of Lamiaceae Honey.

Our work investigated the antimicrobial and prebiotic properties of basil, mint, oregano, rosemary, savory, and thyme honey. The potential antimicrobial action, assessed against the pathogens Acinetobacter baumannii, Escherichia coli, Listeria monocytogenes, Pseudomonas aeruginosa, and Staphylococcus aureus, evidenced the capacity of the honey to influence the pathogenic hydrophobicity and hemolytic activities. Honey inhibited pathogen biofilms, acting especially on the mature biofilms, with inhibition rates of up to 81.62% (caused by the presence of mint honey on L. monocytogenes). S. aureus biofilms were the most susceptible to the presence of honey, with inhibition rates up of to 67.38% in the immature form (caused by basil honey) and up to 80.32% in the mature form (caused by mint honey). In some cases, the amount of nuclear and proteic material, evaluated by spectrophotometric readings, if also related to the honey's biofilm inhibitory activity, let us hypothesize a defective capacity of building the biofilm scaffold or bacterial membrane damage or an incapability of producing them for the biofilm scaffold. The prebiotic potentiality of the honey was assessed on Lacticaseibacillus casei Shirota, Lactobacillus gasseri, Lacticaseibacillus paracasei subsp. paracasei, and Lacticaseibacillus rhamnosus and indicated their capacity to affect the whole probiotic growth and in vitro adhesive capacity, as well as the antioxidant and cytotoxic abilities, and to inhibit, mainly in the test performed with the L. casei Shirota, L. gasseri, and L. paracasei supernatants, the immature biofilm of the pathogens mentioned above.

Strategies to Overcome Antimicrobial Resistance in Nosocomial Infections, A Review and Update.

Nosocomial infections, also known as healthcare-associated infections, are a significant global concern due to their strong association with high mortality and morbidity in both developed and developing countries. These infections are caused by a variety of pathogens, particularly the ESKAPE group of bacteria, which includes the six pathogens Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp. These bacteria have demonstrated noteworthy resistance to different antibiotics. Antimicrobial resistance mechanisms can manifest in various forms, including restricting drug uptake, modifying drug targets, inactivating drugs, active drug efflux, and biofilm formation. Accordingly, various strategies have been developed to combat antibiotic-resistant bacteria. These strategies encompass the development of new antibiotics, the utilization of bacteriophages that specifically target these bacteria, antimicrobial combination therapy and the use of peptides or enzymes that target the genomes or essential proteins of resistant bacteria. Among promising approaches to overcome antibiotic resistance, the CRISPR/Cas system stands out and offers many advantages. This system enables precise and efficient editing of genetic material at specific locations in the genome. Functioning as a bacterial "adaptive immune system," the CRISPR/Cas system recognizes, degrades, and remembers foreign DNA sequences through the use of spacer DNA segments that are transcribed into CRISPR RNAs (crRNA). This paper has focused on nosocomial infections, specifically the pathogens involved in hospital infections, the mechanisms underlying bacterial resistance, and the strategies currently employed to address this issue. Special emphasis has been placed on the application of CRISPR/Cas technology for overcoming antimicrobial resistance.

ESKAPE Pathogens: Antimicrobial Resistance Patterns, Risk Factors, and Outcomes a Retrospective Cross-Sectional Study of Hospitalized Patients in Palestine.

Antimicrobial resistance to ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp). remains a major challenge in hospital settings. This study aimed to determine the ESKAPE antimicrobial resistance patterns and associated factors with multi-drug resistance strains among hospitalized patients in a single tertiary care medical hospital in Palestine. A single-center retrospective cross-sectional study was conducted by reviewing patients' electronic medical records and laboratory results from November 1, 2021, to November 30, 2022, at the Palestine Medical Complex in Palestine. The study included patients aged > 18 years who had been infected with ESKAPE pathogens 48 hours after hospital admission. This study included 231 patients, of whom 90.5% had MDR infections. In total, 331 clinical samples of ESKAPE pathogens were identified. A. baumannii was the most prevalent MDR pathogen (95.6%) with Carbapenem-resistant exceeding 95%, followed by K. pneumoniae (83.8%) with extended-spectrum cephalosporin resistance exceeding 90%, S. aureus (68.2) with 85% oxacillin-resistance, E. faecium (40%) with 20% vancomycin resistance, P. aeruginosa (22.6%) with 30% carbapenem resistance. Furthermore, emergent colistin resistance has been observed in A. baumannii, K. pneumoniae, and P. aerogenesis. Risk factors for MDR infection included age (p< 0.035), department (p< 0.001), and invasive procedures such as IUC (p< 0.001), CVC (p< 0.000), and MV (p< 0.008). Patients diagnosed with MDR bacteria had increased 30-day mortality (p< 0.001). The findings of this study show alarming MDR among hospitalized patients infected with ESKAPE pathogens, with resistance to first-line antimicrobial agents and emerging resistance to colistin, minimizing treatment options. Healthcare providers and the Ministry of Health must take steps, adopt policies to prevent antimicrobial resistance, adhere to infection control guidelines, implement antimicrobial stewardship programs to prevent and limit the growing health crisis, and support research to discover new treatment options.

Impact of low-dose UV-A in Caenorhabditis elegans during candidate bacterial infections.

Ultraviolet radiation is a non-ionizing radiation produced by longer wavelength energy sources with lower frequency and is categorized into UV-A, UV-B, and UV-C. Minimal exposure to this radiation has several health benefits, which include treating microbial contaminations and skin therapies. However, the antimicrobial action of low-dose UV-A during pathogenic bacterial infections is still unrevealed. In this study, the impact of low-dose UV-A as pre- or post-treatment using the model organism, Caenorhabditis elegans with candidate pathogens (Acinetobacter baumannii and Staphylococcus aureus) mediated infections was investigated. The results indicated enrichment of metabolites, reduced level of antioxidants, increased expression of dopamine biosynthesis and transportation, and decrease in serotonin biosynthesis when the organism was exposed to low-dose UV-A for 5 min. This, in turn, elevated the expression of candidate regulatory proteins involved in lifespan determination, innate immunity, and cAMP-response element binding protein (CREB), which appear to increase the lifespan and brood size of C. elegans during A. baumannii and S. aureus infections. The findings suggested that the low-dose UV-A treatment during A. baumannii and S. aureus infections prolonged the lifespan and increased the egg-laying capacity of C. elegans.