RESUMEN

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) frequently causes both healthcare-associated infections and nosocomial outbreaks in burn medicine/plastic surgery and beyond. Owing to the high antibiotic resistance, infections are difficult to treat, and patient outcomes are often compromised. The environmental persistence capability of CRAB favors its transmission in hospitals. A comprehensive analysis and understanding of CRAB epidemiology and microbiology are essential for guiding management. METHODS: A three-year retrospective cohort study (2020-2022) was conducted in a German tertiary burn and plastic surgery center. In addition to epidemiological analyses, microbiological and molecular techniques, including whole-genome sequencing, were applied for the comprehensive examination of isolates from CRAB-positive patients. RESULTS: During the study period, eight CRAB cases were found, corresponding to an overall incidence of 0.2 CRAB cases per 100 cases and an incidence density of 0.35 CRAB cases per 1000 patient-days. Six cases (75%) were treated in the burn intensive care unit, and four cases (50%) acquired CRAB in the hospital. Molecular analyses comprising 74 isolates supported the epidemiologic assumption that hospital acquisitions occurred within two separate clusters. In one of these clusters, environmental CRAB contamination of anesthesia equipment may have enabled transmission. Furthermore, molecular diversity of CRAB isolates within patients was observed. CONCLUSIONS: CRAB can pose a challenge in terms of infection prevention and control, especially if cases are clustered in time and space on a ward. Our study demonstrates that high-resolution phylogenetic analysis of several bacterial isolates from single patients can greatly aid in understanding transmission chains and helps to take precision control measures.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Carbapenémicos , Infección Hospitalaria , Control de Infecciones , Acinetobacter baumannii/genética , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/aislamiento & purificación , Humanos , Infecciones por Acinetobacter/epidemiología , Infecciones por Acinetobacter/microbiología , Alemania/epidemiología , Carbapenémicos/farmacología , Estudios Retrospectivos , Masculino , Femenino , Persona de Mediana Edad , Infección Hospitalaria/epidemiología , Infección Hospitalaria/microbiología , Anciano , Adulto , Control de Infecciones/métodos , Epidemiología Molecular , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Quemaduras/microbiología , Quemaduras/complicaciones , Cirugía Plástica , Unidades de Quemados , Secuenciación Completa del Genoma , Incidencia , Pruebas de Sensibilidad Microbiana

RESUMEN

Acinetobacter species such as A. venetianus and A. guillouiae have been studied for various biotechnology applications, including bioremediation of recalcitrant and harmful environmental contaminants, as well as bioengineering of enzymes and diagnostic materials. Bacteria used in biotechnology are often combined with other microorganisms in mixtures to formulate efficacious commercial products. However, if the mixture contained a closely related Acinetobacter pathogen such as A. baumannii (Ab), it remains unclear whether the survival and virulence of Ab would be masked or augmented. This uncertainty poses a challenge in ensuring the safety of such biotechnology products, since Ab is one of the most significant pathogens for both hospital and community -acquired infections. This research aimed to investigate the growth and virulence of Ab within a mixture of 11 bacterial species formulated as a mock microbial mixture (MM). Growth challenges with environmental stressors (i.e., temperature, pH, sodium, iron, and antibiotics) revealed that Ab could thrive under diverse conditions except in the presence of ciprofloxacin. When cultured alone, Ab exhibited significantly more growth in the presence of almost all the environmental stressors than when it was co-incubated with the MM. During the exposure of A549 lung epithelial cells to the MM, Ab growth was stimulated compared to that in standard mammalian culture media. Cytotoxicity caused by Ab was suppressed in the presence of the MM. Lymphocytes were significantly reduced in mice exposed to Ab with or without MM via intravenous injection. The levels of the splenic cytokines IL-1α, IL-1ß, MCP-1, and MIP-1α were significantly reduced 24 h after exposure to Ab + MM. This study demonstrated that the presence of the MM marginally but significantly reduced the growth and virulence of Ab, which has implications for the safety of mixtures of microorganisms for biotechnological applications. Furthermore, these findings expand our understanding of the virulence of Ab during host-pathogen interactions.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Animales , Acinetobacter baumannii/patogenicidad , Acinetobacter baumannii/crecimiento & desarrollo , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/genética , Virulencia , Ratones , Humanos , Infecciones por Acinetobacter/microbiología , Células A549 , Antibacterianos/farmacología , Femenino , Citocinas/metabolismo , Viabilidad Microbiana/efectos de los fármacos

RESUMEN

BACKGROUND: Nosocomial infections are a global problem in hospitals all around the world. It is considered a major health problem, especially in developing countries. The increase in the patient's stay in hospitals has increased the mortality rate, and consequently, the costs drastically increase. The main purpose of using disinfectants in the hospital environment is to reduce the risk of nosocomial infections. Ethylene diamine tetra acetic acid (EDTA) causes lysis and increases susceptibility to antimicrobial agents in the planktonic form of bacteria. This substance affects the permeability of the outer membrane of bacteria. It also prevents the formation of biofilms by bacteria. MATERIALS AND METHODS: In the current study, 120 isolates of Acinetobacter baumannii (A. baumannii) were confirmed by phenotypic and genotypic methods. Antibiogram was performed and then the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of isolates against 5% sodium hypochlorite, ethanol %70, sayasept-HP 2%, chlorhexidine 2%, dettol 4/8% were evaluated. In addition, the disinfectant effect was re-evaluated with the mixture of EDTA solution. All isolates were examined for biofilm presence by crystal violet staining method in triplicates and repeated three times for each strain. Also for all isolates detection of efflux pump genes (Qac-E, qacE-Δ1, SUG-E) by PCR technique was done. RESULTS: Antibiogram results of A. baumannii showed that 6.7% were Multi-drug-resistant (MDR), and 89.2% were Extensively drug-resistant (XDR) isolates. The highest effect of disinfectants was related to 5% sodium hypochlorite, and the least effect was 70% ethanol. EDTA increases the efficacy of selected disinfectants significantly. The highest prevalence of the efflux pump genes was related to SUG-E (95%) and Qac-E (91.7%), and, the qacE-Δ1 gene with 12.5%. The biofilm production rate was 91.3% among all isolates. CONCLUSION: The best and safest way to disinfect hospital floors and surfaces is to choose the right disinfectants, and learn how to use them properly. In this study, a mixture of disinfectants and EDTA had a significant effect on bactericidal activity. it was found that improper use of disinfectants, especially the use of sub-inhibitory dilutions, increases the resistance of bacteria to disinfectants.

Asunto(s)

Acinetobacter baumannii , Biopelículas , Desinfectantes , Genotipo , Pruebas de Sensibilidad Microbiana , Fenotipo , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/genética , Acinetobacter baumannii/fisiología , Acinetobacter baumannii/aislamiento & purificación , Desinfectantes/farmacología , Humanos , Irán , Ácido Edético/farmacología , Farmacorresistencia Bacteriana/genética , Antibacterianos/farmacología , Infecciones por Acinetobacter/microbiología , Hipoclorito de Sodio/farmacología , Infección Hospitalaria/microbiología , Clorhexidina/farmacología

RESUMEN

Introduction: Acinetobacter baumannii (AB) is rising as a human pathogen of critical priority worldwide as it is the leading cause of opportunistic infections in healthcare settings and carbapenem-resistant AB is listed as a "super bacterium" or "priority pathogen for drug resistance" by the World Health Organization. Methods: Clinical isolates of A. baumannii were collected and tested for antimicrobial susceptibility. Among them, carbapenem-resistant and carbapenem-sensitive A. baumannii were subjected to prokaryotic transcriptome sequencing. The change of sRNA and mRNA expression was analyzed by bioinformatics and validated by quantitative reverse transcription-PCR. Results: A total of 687 clinical isolates were collected, of which 336 strains of A. baumannii were resistant to carbapenem. Five hundred and six differentially expressed genes and nineteen differentially expressed sRNA candidates were discovered through transcriptomic profile analysis between carbapenem-resistant isolates and carbapenem-sensitive isolates. Possible binding sites were predicted through software for sRNA21 and adeK, sRNA27 and pgaC, sRNA29 and adeB, sRNA36 and katG, indicating a possible targeting relationship. A negative correlation was shown between sRNA21 and adeK (r = -0.581, P = 0.007), sRNA27 and pgaC (r = -0.612, P = 0.004), sRNA29 and adeB (r = -0.516, P = 0.020). Discussion: This study preliminarily screened differentially expressed mRNA and sRNA in carbapenem-resistant A. baumannii, and explored possible targeting relationships, which will help further reveal the resistance mechanism and provide a theoretical basis for the development of drugs targeting sRNA for the prevention and treatment of carbapenem-resistant A. baumannii infection.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Antibacterianos , Carbapenémicos , Perfilación de la Expresión Génica , ARN Mensajero , Acinetobacter baumannii/genética , Acinetobacter baumannii/efectos de los fármacos , Carbapenémicos/farmacología , Humanos , Infecciones por Acinetobacter/microbiología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Antibacterianos/farmacología , Regulación Bacteriana de la Expresión Génica , Pruebas de Sensibilidad Microbiana , Biología Computacional/métodos , ARN Bacteriano/genética , ARN Pequeño no Traducido/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Transcriptoma , Genoma Bacteriano/genética

RESUMEN

Acinetobacter baumannii is a pathogenic and multidrug-resistant Gram-negative bacterium that causes severe nosocomial infections. To better understand the mechanism of pathogenesis, we compare the proteomes of uninfected and infected human cells, revealing that transcription factor FOS is the host protein most strongly induced by A. baumannii infection. Pharmacological inhibition of FOS reduces the cytotoxicity of A. baumannii in cell-based models, and similar results are also observed in a mouse infection model. A. baumannii outer membrane vesicles (OMVs) are shown to activate the aryl hydrocarbon receptor (AHR) of host cells by inducing the host enzyme tryptophan-2,3-dioxygenase (TDO), producing the ligand kynurenine, which binds AHR. Following ligand binding, AHR is a direct transcriptional activator of the FOS gene. We propose that A. baumannii infection impacts the host tryptophan metabolism and promotes AHR- and FOS-mediated cytotoxicity of infected cells.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Quinurenina , Receptores de Hidrocarburo de Aril , Receptores de Hidrocarburo de Aril/metabolismo , Receptores de Hidrocarburo de Aril/genética , Acinetobacter baumannii/metabolismo , Acinetobacter baumannii/genética , Acinetobacter baumannii/efectos de los fármacos , Humanos , Animales , Ratones , Infecciones por Acinetobacter/microbiología , Infecciones por Acinetobacter/metabolismo , Quinurenina/metabolismo , Proteínas Proto-Oncogénicas c-fos/metabolismo , Proteínas Proto-Oncogénicas c-fos/genética , Triptófano/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Interacciones Huésped-Patógeno

RESUMEN

Objectives: To summarize the clinical characteristics, outcomes and identify risk factors of Acinetobacter baumannii (AB) meningitis in children. Methods: This was a single-center, retrospective study. Children hospitalized between January 2016 and December 2021 who were diagnosed with AB meningitis were included. The clinical characteristics and outcomes were reviewed. Risk factors were determined using univariate analyses (chi-square and Mann-Whitney U tests). Results: Seventeen patients were included; 15 cases were secondary to neurosurgery, and two were neonates with primary bacterial meningitis. Common symptoms included fever, convulsions and nervous system abnormalities. Cerebrospinal fluid (CSF) tests typically showed increased white blood cell counts dominated by neutrophils, reduced glucose levels and elevated protein levels. Ten patients were successfully treated (successful treatment [ST] group); seven had failed treatment (failed treatment [FT] group). Univariate analyses revealed that mechanical ventilation, routine white cell counts in the peripheral blood, procalcitonin, protein in the CSF, septic shock and carbapenem-resistant AB (CRAB) differed significantly between the groups. Conclusion: AB meningitis in children has a high mortality rate. FT was associated with mechanical ventilation, septic shock, CRAB, lower peripheral leukocyte counts, higher protein levels in the CSF and procalcitonin. Larger studies are needed to identify independent risk factors for adverse outcomes.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Antibacterianos , Meningitis Bacterianas , Centros de Atención Terciaria , Humanos , Femenino , Masculino , Factores de Riesgo , China/epidemiología , Estudios Retrospectivos , Preescolar , Lactante , Infecciones por Acinetobacter/microbiología , Meningitis Bacterianas/microbiología , Meningitis Bacterianas/mortalidad , Antibacterianos/uso terapéutico , Niño , Resultado del Tratamiento , Recién Nacido , Carbapenémicos/uso terapéutico , Recuento de Leucocitos , Adolescente

RESUMEN

The quorum sensing (QS) system mediated by the abaI gene in Acinetobacter baumannii is crucial for various physiological and pathogenic processes. In this study, we constructed a stable markerless abaI knockout mutant (ΔabaI) strain using a pEXKm5-based allele replacement method to investigate the impact of abaI on A. baumannii. Proteomic analysis revealed significant alterations in protein expression between the wild type (WT) and ΔabaI mutant strains, particularly in proteins associated with membrane structure, antibiotic resistance, and virulence. Notably, the downregulation of key outer membrane proteins such as SurA, OmpA, OmpW, and BamA suggests potential vulnerabilities in outer membrane integrity, which correlate with structural abnormalities in the ΔabaI mutant strain, including irregular cell shapes and compromised membrane integrity, observed by scanning and transmission electron microscopy. Furthermore, diminished expression of regulatory proteins such as OmpR and GacA-GacS highlights the broader regulatory networks affected by abaI deletion. Functional assays revealed impaired biofilm formation and surface-associated motility in the mutant strain, indicative of altered colonization capabilities. Interestingly, the mutant showed a complex antibiotic susceptibility profile. While it demonstrated increased susceptibility to membrane-targeting antibiotics, its response to beta-lactams was more nuanced. Despite increased expression of metallo-beta-lactamase (MBL) superfamily proteins and DcaP-like protein, the mutant unexpectedly showed lower MICs for carbapenems (imipenem and meropenem) compared to the wild-type strain. This suggests that abaI deletion affects antibiotic susceptibility through multiple, potentially competing mechanisms. Further investigation is needed to fully elucidate the interplay between quorum sensing, antibiotic resistance genes, and overall antibiotic susceptibility in A. baumannii. Our findings underscore the multifaceted role of the abaI gene in modulating various cellular processes and highlight its significance in A. baumannii physiology, pathogenesis, and antibiotic resistance. Targeting the abaI QS system may offer novel therapeutic strategies for this clinically significant pathogen.

Asunto(s)

Acinetobacter baumannii , Antibacterianos , Proteínas Bacterianas , Biopelículas , Mutación , Percepción de Quorum , Acinetobacter baumannii/genética , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/patogenicidad , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Virulencia/genética , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Percepción de Quorum/genética , Percepción de Quorum/efectos de los fármacos , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Infecciones por Acinetobacter/microbiología , Infecciones por Acinetobacter/tratamiento farmacológico , Proteómica

RESUMEN

BACKGROUND: There are multiple antibiotic regimens for the treatment of carbapenem-resistant Acinetobacter baumannii (CRAB) in clinical practice. We conducted this meta-analysis to compare the efficacy and safety of cefiderocol-based regimens and colistin-based regimens in the treatment of CRAB infections. METHODS: Two authors independently searched the PubMed, Web of Science, Embase, and Cochrane databases from their establishment to April 15, 2024, to search for randomized controlled trials (RCTs) or cohort studies, and compared the clinical efficacy and safety of cefiderocol-based regimens and colistin-based regimens in the treatment of CRAB infections. The Newcastle Ottawa Scale (NOS) checklist was used to evaluate the quality of the included studies. The primary outcome was all-cause mortality, and subgroup analysis was conducted on the basis of the site of infection and the risk of bias in the studies. Trial sequential analysis (TSA) was then conducted. RESULTS: Six observational studies were included, with 251 cases in the cefiderocol-based group and 372 cases in the colistin-based group. Compared to the colistin-based group, the cefiderocol-based group had lower all-cause mortality (RR = 0.71, 95% CI: 0.54-0.92, P = 0.01) and 30-day mortality (RR = 0.64, 95% CI: 0.43-0.95, P = 0.03). However, for the 14-day and 28-day mortality rates, there was no statistically significant difference between two groups. According to the subgroup analysis, among patients with bloodstream infection (BSI), the cefiderocol-based group had lower all-cause mortality, but it did not reduce the mortality of ventilator-associated pneumonia (VAP) patients. The result of TSA showed that our conclusions are reliable. There was no significant statistical difference in the microbiological cure rate, clinical cure rate, or duration of hospitalization. In addition, the cefiderocol-based group did not have an increased incidence of acute kidney injury (AKI). CONCLUSIONS: Compared with the colistin-based regimens, the cefiderocol-based regimens were significantly associated with a lower risk of mortality in CRAB-infected patients, especially for patients with BSI. However, they did not show any advantages in terms of the clinical cure rate or microbiological cure rate, nor did they reduce the incidence of AKI. PROSPERO REGISTRATION NUMBER: CRD42023487213.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Antibacterianos , Carbapenémicos , Cefiderocol , Colistina , Colistina/uso terapéutico , Colistina/farmacología , Acinetobacter baumannii/efectos de los fármacos , Humanos , Infecciones por Acinetobacter/tratamiento farmacológico , Infecciones por Acinetobacter/mortalidad , Infecciones por Acinetobacter/microbiología , Antibacterianos/uso terapéutico , Antibacterianos/farmacología , Carbapenémicos/uso terapéutico , Carbapenémicos/farmacología , Cefalosporinas/uso terapéutico , Farmacorresistencia Bacteriana Múltiple , Resultado del Tratamiento

RESUMEN

Outer membrane vesicles (OMVs) are nanostructures derived from the outer membrane of Gram-negative bacteria. We previously demonstrated that vaccination with endotoxin-free OMVs isolated from an Acinetobacter baumannii strain lacking lipooligosaccharide (LOS) biosynthesis, due to a mutation in lpxD, provides full protection in a murine sepsis model. The present study characterizes the protein content of highly-purified OMVs isolated from LOS-replete and LOS-deficient strains. Four purification methods were evaluated to obtain highly purified OMV preparations: ultracentrifugation, size exclusion chromatography (SEC), ultracentrifugation followed by SEC, and Optiprep™. OMVs from each method were characterized using nanoparticle tracking analysis and electron microscopy. OMVs from LOS-deficient and LOS-replete strains purified using the Optiprep™ method were subjected to LC-MS/MS analysis to determine protein content. Significant differences in protein composition between OMVs from LOS-deficient and LOS-replete strains were found. Computational analyses using Bepipred 3.0 and SEMA 2.0 indicated that the lack of LOS led to the overexpression of immunogenic proteins found in LOS-containing OMVs and the presence of immune-stimulating proteins absent in LOS-replete OMVs. These findings have important implications for developing OMV-based vaccines against A. baumannii, using both LOS-containing and LOS-free OMVs preparations.

Asunto(s)

Acinetobacter baumannii , Proteínas de la Membrana Bacteriana Externa , Lipopolisacáridos , Acinetobacter baumannii/metabolismo , Acinetobacter baumannii/genética , Lipopolisacáridos/biosíntesis , Proteínas de la Membrana Bacteriana Externa/metabolismo , Proteínas de la Membrana Bacteriana Externa/genética , Infecciones por Acinetobacter/microbiología , Animales , Ratones , Espectrometría de Masas en Tándem , Membrana Externa Bacteriana/metabolismo

RESUMEN

The use of monoclonal antibodies for the control of drug resistant nosocomial bacteria may alleviate a reliance on broad spectrum antimicrobials for treatment of infection. We identify monoclonal antibodies that may prevent infection caused by carbapenem resistant Acinetobacter baumannii. We use human immune repertoire mice (Kymouse platform mice) as a surrogate for human B cell interrogation to establish an unbiased strategy to probe the antibody-accessible target landscape of clinically relevant A. baumannii. After immunisation of the Kymouse platform mice with A. baumannii derived outer membrane vesicles (OMV) we identify 297 antibodies and analyse 26 of these for functional potential. These antibodies target lipooligosaccharide (OCL1), the Oxa-23 protein, and the KL49 capsular polysaccharide. We identify a single monoclonal antibody (mAb1416) recognising KL49 capsular polysaccharide to demonstrate prophylactic in vivo protection against a carbapenem resistant A. baumannii lineage associated with neonatal sepsis mortality in Asia. Our end-to-end approach identifies functional monoclonal antibodies with prophylactic potential against major lineages of drug resistant bacteria accounting for phylogenetic diversity and clinical relevance without existing knowledge of a specific target antigen. Such an approach might be scaled for a additional clinically important bacterial pathogens in the post-antimicrobial era.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Anticuerpos Monoclonales , Ratones Transgénicos , Acinetobacter baumannii/inmunología , Acinetobacter baumannii/genética , Animales , Humanos , Anticuerpos Monoclonales/inmunología , Anticuerpos Monoclonales/farmacología , Infecciones por Acinetobacter/inmunología , Infecciones por Acinetobacter/prevención & control , Infecciones por Acinetobacter/microbiología , Ratones , Antibacterianos/farmacología , Anticuerpos Antibacterianos/inmunología , Femenino , Carbapenémicos/farmacología , Farmacorresistencia Bacteriana/inmunología , Farmacorresistencia Bacteriana/genética , Lipopolisacáridos/inmunología

RESUMEN

The emission of glyphosate and antibiotic residues from human activities threatens the diversity and functioning of the microbial community. This study examines the impact of a glyphosate-based herbicide (GBH) and common antibiotics on Gram-negative bacteria within the ESKAPEE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp. and Escherichia coli). Ten strains, including type and multidrug-resistant strains for each species were analysed and eight antibiotics (cefotaxime, meropenem, aztreonam, ciprofloxacin, gentamicin, tigecycline, sulfamethoxazole-trimethoprim, and colistin) were combined with the GBH. While most combinations yielded additive or indifferent effects in 70 associations, antagonistic effects were observed with ciprofloxacin and gentamicin in five strains. GBH notably decreased the minimum inhibitory concentration of colistin in eight strains and displayed synergistic activity with meropenem against metallo-ß-lactamase (MBL)-producing strains. Investigation into the effect of GBH properties on outer membrane permeability involved exposing strains to a combination of this GBH and vancomycin. Results indicated that GBH rendered strains sensitive to vancomycin, which is typically ineffective against Gram-negative bacteria. Furthermore, we examined the impact of GBH in combination with three carbapenem agents on 14 strains exhibiting varying carbapenem-resistance mechanisms to assess its effect on carbapenemase activity. The GBH efficiently inhibited MBL activity, demonstrating similar effects to EDTA (ethylenediaminetetraacetic acid). Chelating effect of GBH may have multifaceted impacts on bacterial cells, potentially by increasing outer membrane permeability and inactivating metalloenzyme activity.

Asunto(s)

Acinetobacter baumannii , Antibacterianos , Glicina , Glifosato , Bacterias Gramnegativas , Herbicidas , Pruebas de Sensibilidad Microbiana , Glicina/análogos & derivados , Glicina/farmacología , Antibacterianos/farmacología , Herbicidas/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Acinetobacter baumannii/efectos de los fármacos , Klebsiella pneumoniae/efectos de los fármacos , Humanos , Escherichia coli/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Ciprofloxacina/farmacología , Enterococcus faecium/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Colistina/farmacología , Vancomicina/farmacología , Enterobacter/efectos de los fármacos , Sinergismo Farmacológico , Meropenem/farmacología , Fenotipo , Gentamicinas/farmacología

RESUMEN

Introduction. As growing numbers of patients are at higher risk of infection, novel topical broad-spectrum antimicrobials are urgently required for wound infection management. Robust pre-clinical studies should support the development of such novel antimicrobials.Gap statement. To date, evidence of robust investigation of the cytotoxicity and antimicrobial spectrum of activity of antimicrobial peptides (AMP)s is lacking in published literature. Using a more clinical lens, we address this gap in experimental approach, building on our experience with poly-l-lysine (PLL)-based AMP polymers.Aim. To evaluate the in vitro bactericidal activity and cytotoxicity of a PLL-based 16-armed star AMP polymer, designated 16-PLL10, as a novel candidate antimicrobial.Methods. Antimicrobial susceptibilities of clinical isolates and reference strains of ESKAPE (Enterococcus spp., Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter spp.) pathogens, to 16-PLL10 were investigated. Human erythrocyte haemolysis and keratinocyte viability assays were used to assess toxicity. Modifications were made to 16-PLL10 and re-evaluated for improvement.Results. Minimum bactericidal concentration of 16-PLL10 ranged from 1.25 µM to ≥25 µM. At 2.5 µM, 16-PLL10 was broadly bactericidal against ESKAPE strains/wound isolates. Log-reduction in colony forming units (c.f.u.) per millilitre after 1 h, ranged from 0.3 (E. cloacae) to 5.6 (K. pneumoniae). At bactericidal concentrations, 16-PLL10 was toxic to human keratinocyte and erythrocytes. Conjugates of 16-PLL10, Trifluoroacetylated (TFA)-16-PLL10, and Poly-ethylene glycol (PEG)ylated 16-PLL10, synthesised to address toxicity, only moderately reduced cytotoxicity and haemolysis.Conclusions. Due to poor selectivity indices, further development of 16-PLL10 is unlikely warranted. However, considering the unmet need for novel topical antimicrobials, the ease of AMP polymer synthesises/modification is attractive. To support more rational development, prioritising clinically relevant pathogens and human cells, to establish selective toxicity profiles in vitro, is critical. Further characterisation and discovery utilising artificial intelligence and computational screening approaches can accelerate future AMP nanomaterial development.

Asunto(s)

Péptidos Antimicrobianos , Pruebas de Sensibilidad Microbiana , Polilisina , Humanos , Polilisina/farmacología , Polilisina/química , Péptidos Antimicrobianos/farmacología , Péptidos Antimicrobianos/química , Antibacterianos/farmacología , Antibacterianos/química , Eritrocitos/efectos de los fármacos , Infección de Heridas/microbiología , Infección de Heridas/tratamiento farmacológico , Klebsiella pneumoniae/efectos de los fármacos , Hemólisis/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Staphylococcus aureus/efectos de los fármacos , Polímeros/farmacología , Polímeros/química , Acinetobacter baumannii/efectos de los fármacos , Queratinocitos/efectos de los fármacos , Bacterias/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos

RESUMEN

In this work, the antibiotic resistance, biofilm formation capability, and clonal relatedness of 50 A. baumannii isolates collected from three hospitals in Ardabil city, Iran, were evaluated. Antibiotic sensitivity and biofilm formation of isolates were determined by disk diffusion and microtiter-plate methods, respectively. Molecular typing of isolates was also performed using repetitive sequence-based PCR (REP-PCR). The majority of isolates were resistant to cephems, aminoglycosides, and carbapenems, with 80 % classified as multi-drug resistant (MDR). While, only isolates collected from blood and tracheal were resistant to colistin. Additionally, 42 isolates (84 %) had biofilm formation capability. According to rep-PCR results, 34 isolates showed similar banding patterns, while 16 isolates had unique banding patterns. Finally, based on the molecular analysis, there was a direct relationship between biofilm formation and the antibiotic resistance of isolates. In other words, MDR isolates had a higher ability to form biofilm.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Antibacterianos , Biopelículas , Farmacorresistencia Bacteriana Múltiple , Pruebas de Sensibilidad Microbiana , Biopelículas/crecimiento & desarrollo , Biopelículas/efectos de los fármacos , Humanos , Antibacterianos/farmacología , Infecciones por Acinetobacter/microbiología , Irán , Farmacorresistencia Bacteriana Múltiple/genética , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/genética , Acinetobacter baumannii/aislamiento & purificación , Acinetobacter baumannii/fisiología , Tipificación Molecular , Reacción en Cadena de la Polimerasa , Colistina/farmacología , Adulto , Hospitales , Masculino , Femenino , Genotipo , Persona de Mediana Edad

RESUMEN

BACKGROUND: This study was conducted to explore the effects of erythromycin on biofilms comprising Acinetobacter baumannii (A baumannii). METHODS: To clarify the effect of erythromycin on the biofilms of A baumannii, we collected pure Ab strains isolated and identified from a variety of sample types extracted from patients in the microbiological laboratory of our hospital from April to August 2023, and divided them into an experimental group (treated with erythromycin) and a control group (without erythromycin). The morphology and quantity of A baumannii biofilm were observed at 24h, 48h, 72h, and 5d post-treatment, respectively, and the expression of quorum sensing (QS) system gene (abaI, abaR) mRNA was detected by fluorescence quantitative PCR. RESULTS: The results showed that A baumanniis are prone to form multiple drug-resistant (MDR) bacteria, against which the most commonly used clinical antibiotics are ineffective. Overall, we found that the number of bacteria, the number of bacteria in the biofilm, and the number of biofilms formed gradually increased over time, with a statistical difference (P < .05). After the addition of erythromycin, significant improvements in biofilm formation were achieved, indicating that erythromycin can destroy A baumannii biofilms, inhibiting bacterial growth to a certain extent. The expression levels of abaI and abaR gradually increased over time, indicating that the role of the QS system became more apparent over time. Biofilm formation is related to the QS system of A baumanniis. After erythromycin treatment, abaI and abaR mRNA expression was downregulated in the experimental group. CONCLUSION: Erythromycin disrupts A baumannii biofilms by destroying the quorum sensing system.

Asunto(s)

Acinetobacter baumannii , Antibacterianos , Biopelículas , Eritromicina , Percepción de Quorum , Acinetobacter baumannii/efectos de los fármacos , Acinetobacter baumannii/genética , Biopelículas/efectos de los fármacos , Eritromicina/farmacología , Percepción de Quorum/efectos de los fármacos , Antibacterianos/farmacología , Humanos , Infecciones por Acinetobacter/microbiología , Infecciones por Acinetobacter/tratamiento farmacológico , Pruebas de Sensibilidad Microbiana , Farmacorresistencia Bacteriana Múltiple/genética

RESUMEN

An efficient synthetic strategy has been developed to achieve a pyruvic acid acetal containing tetrasaccharide repeating unit corresponding to the K82 capsular polysaccharide of Acinetobacter baumannii LUH5534 strain in very good yield. The synthetic scheme involves the use of suitably functionalized monosaccharide thioglycosides as glycosyl donors and a combination of N-iodosuccinimide (NIS) and trimethylsilyl trifluoromethanesulfonate (TMSOTf) as thiophilic glycosylation activator to furnish satisfactory yield of the products with appropriate stereochemistry at the glycosidic linkages. Incorporation of the (R)-pyruvic acid acetal in the d-galactose moiety was achieved in very good yield by the treatment of the diol derivative with methyl 2,2-bis(p-methylphenylthio)propionate in the presence of a combination of NIS and triflic acid.

Asunto(s)

Acetales , Acinetobacter baumannii , Oligosacáridos , Polisacáridos Bacterianos , Acinetobacter baumannii/química , Acetales/química , Polisacáridos Bacterianos/química , Polisacáridos Bacterianos/síntesis química , Oligosacáridos/química , Oligosacáridos/síntesis química , Ácido Pirúvico/química , Secuencia de Carbohidratos , Cápsulas Bacterianas/química

RESUMEN

The ESKAPE family, comprising Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp., poses a significant global threat due to their heightened virulence and extensive antibiotic resistance. These pathogens contribute largely to the prevalence of nosocomial or hospital-acquired infections, resulting in high morbidity and mortality rates. To tackle this healthcare problem urgent measures are needed, including development of innovative vaccines and therapeutic strategies. Designing vaccines involves a complex and resource-intensive process of identifying protective antigens and potential vaccine candidates (PVCs) from pathogens. Reverse vaccinology (RV), an approach based on genomics, made this process more efficient by leveraging bioinformatics tools to identify potential vaccine candidates. In recent years, artificial intelligence and machine learning (ML) techniques has shown promise in enhancing the accuracy and efficiency of reverse vaccinology. This study introduces a supervised ML classification framework, to predict potential vaccine candidates specifically against ESKAPE pathogens. The model's training utilized biological and physicochemical properties from a dataset containing protective antigens and non-protective proteins of ESKAPE pathogens. Conventional autoencoders based strategy was employed for feature encoding and selection. During the training process, seven machine learning algorithms were trained and subjected to Stratified 5-fold Cross Validation. Random Forest and Logistic Regression exhibited best performance in various metrics including accuracy, precision, recall, WF1 score, and Area under the curve. An ensemble model was developed, to take collective strengths of both the algorithms. To assess efficacy of our final ensemble model, a high-quality benchmark dataset was employed. VacSol-ML(ESKAPE) demonstrated outstanding discrimination between protective vaccine candidates (PVCs) and non-protective antigens. VacSol-ML(ESKAPE), proves to be an invaluable tool in expediting vaccine development for these pathogens. Accessible to the public through both a web server and standalone version, it encourages collaborative research. The web-based and standalone tools are available at http://vacsolml.mgbio.tech/.

Asunto(s)

Antígenos Bacterianos , Vacunas Bacterianas , Aprendizaje Automático , Antígenos Bacterianos/inmunología , Humanos , Vacunas Bacterianas/inmunología , Klebsiella pneumoniae/inmunología , Klebsiella pneumoniae/genética , Klebsiella pneumoniae/patogenicidad , Enterococcus faecium/inmunología , Enterococcus faecium/genética , Staphylococcus aureus/inmunología , Staphylococcus aureus/genética , Acinetobacter baumannii/inmunología , Pseudomonas aeruginosa/inmunología , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidad , Biología Computacional/métodos , Enterobacter/inmunología , Enterobacter/genética , Vacunología/métodos

RESUMEN

We compared clinical outcomes of patients who received monotherapy and combination therapy for treatment of MDR A. baumannii VAP. 170 patients were included. Vasopressor use and mortality rate were higher for combination therapy (69.3% versus 28.6%, p=0.024; 67.5% versus 14.3%, p=0.007; respectively). Majority received polymyxin B-based combination therapy, with higher mortality than those without polymyxin B (80.2% versus 19.8%, p=0.043). After adjusting for vasopressor use, monotherapy, dual combination, and triple combination therapy were not associated with mortality (aHR 0.24, 95% CI 0.03 to 1.79, p=0.169; aHR 1.26, 95% CI 0.79 to 2.00, p=0.367; aHR 0.93, 95% CI 0.57 to 1.49, p=0.744; respectively). There was no difference in adverse effects and length of stay between the two groups. Mortality from MDR A. baumannii VAP was high and not associated with monotherapy or combination therapy after adjustment for vasopressor use. Antibiotic regimens other than those containing polymyxin are urgently needed for the treatment of these infections.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter baumannii , Antibacterianos , Farmacorresistencia Bacteriana Múltiple , Quimioterapia Combinada , Neumonía Asociada al Ventilador , Centros de Atención Terciaria , Humanos , Acinetobacter baumannii/efectos de los fármacos , Antibacterianos/uso terapéutico , Femenino , Masculino , Neumonía Asociada al Ventilador/tratamiento farmacológico , Neumonía Asociada al Ventilador/microbiología , Persona de Mediana Edad , Infecciones por Acinetobacter/tratamiento farmacológico , Infecciones por Acinetobacter/mortalidad , Infecciones por Acinetobacter/microbiología , Anciano , Resultado del Tratamiento , Adulto , Polimixina B/uso terapéutico , Polimixina B/administración & dosificación , Estudios Retrospectivos

RESUMEN

Background: Type VI secretion system (T6SS) is widely present in Gram-negative bacteria and directly mediates antagonistic prokaryote interactions. PAAR (proline-alanine-alanine-arginine repeats) proteins have been proven essential for T6SS-mediated secretion and target cell killing. Although PAAR proteins are commonly found in A. baumannii, their biological functions are not fully disclosed yet. In this study, we investigated the functions of a PAAR protein termed TagP (T6SS-associated-gene PAAR), encoded by the gene ACX60_RS09070 outside the core T6SS locus of A. baumannii strain ATCC 17978. Methods: In this study, tagP null and complement A. baumannii ATCC 17978 strains were constructed. The influence of TagP on T6SS function was investigated through Hcp detection and bacterial competition assay; the influence on environmental fitness was studied through in vitro growth, biofilm formation assay, surface motility assay, survivability in various simulated environmental conditions; the influence on pathogenicity was explored through cell adhesion and invasion assays, intramacrophage survival assay, serum survival assay, and G. melonella Killing assays. Quantitative transcriptomic and proteomic analyses were utilized to observe the global impact of TagP on bacterial status. Results: Compared with the wildtype strain, the tagP null mutant was impaired in several tested phenotypes such as surface motility, biofilm formation, tolerance to adverse environments, adherence to eukaryotic cells, endurance to serum complement killing, and virulence to Galleria melonella. Notably, although RNA-Seq and proteomics analysis revealed that many genes were significantly down-regulated in the tagP null mutant compared to the wildtype strain, there is no significant difference in their antagonistic abilities. We also found that Histone-like nucleoid structuring protein (H-NS) was significantly upregulated in the tagP null mutant at both mRNA and protein levels. Conclusions: This study enriches our understanding of the biofunction of PAAR proteins in A. baumannii. The results indicates that TagP involved in a unique modulation of fitness and virulence control in A. baumannii, it is more than a classic PAAR protein involved in T6SS, while how TagP play roles in the fitness and virulence of A. baumannii needs further investigation to clarify.

Asunto(s)

Acinetobacter baumannii , Proteínas Bacterianas , Biopelículas , Sistemas de Secreción Tipo VI , Acinetobacter baumannii/genética , Acinetobacter baumannii/patogenicidad , Acinetobacter baumannii/metabolismo , Virulencia/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Sistemas de Secreción Tipo VI/genética , Sistemas de Secreción Tipo VI/metabolismo , Biopelículas/crecimiento & desarrollo , Animales , Regulación Bacteriana de la Expresión Génica , Factores de Virulencia/genética , Factores de Virulencia/metabolismo , Proteómica , Perfilación de la Expresión Génica , Adhesión Bacteriana/genética , Ratones , Infecciones por Acinetobacter/microbiología , Aptitud Genética , Macrófagos/microbiología , Proteoma

RESUMEN

We investigated the activity of cefiderocol/ß-lactamase inhibitor combinations against clinical strains with different susceptibility profiles to cefiderocol to explore the potentiality of antibiotic combinations as a strategy to contain the major public health problem of multidrug-resistant (MDR) pathogens. Specifically, we evaluated the synergistic activity of cefiderocol with avibactam, sulbactam, or tazobactam on three of the most "Critical Priority" group of MDR bacteria (carbapenem-resistant Enterobacterales, Pseudomonas aeruginosa, and Acinetobacter baumannii). Clinical isolates were genomically characterized by Illumina iSeq 100. The synergy test was conducted with time-kill curve assays. Specifically, cefiderocol/avibactam, /sulbactam, or /tazobactam combinations were analyzed. Synergism was assigned if bacterial grow reduction reached 2 log10 CFU/mL. We reported the high antimicrobial activity of the cefiderocol/sulbactam combination against carbapenem-resistant Enterobacterales, P. aeruginosa, and A. baumannii; of the cefiderocol/avibactam combination against carbapenem-resistant Enterobacterales; and of the cefiderocol/tazobactam combination against carbapenem-resistant Enterobacterales and P. aeruginosa. Our results demonstrate that all ß-lactamase inhibitors (BLIs) tested are able to enhance cefiderocol antimicrobial activity, also against cefiderocol-resistant isolates. The cefiderocol/sulbactam combination emerges as the most promising combination, proving to highly enhance cefiderocol activity in all the analyzed carbapenem-resistant Gram-negative isolates, whereas the Cefiderocol/tazobactam combination resulted in being active only against carbapenem-resistant Enterobacterales and P. aeruginosa, and cefiderocol/avibactam was only active against carbapenem-resistant Enterobacterales.

Asunto(s)

Antibacterianos , Compuestos de Azabiciclo , Cefiderocol , Cefalosporinas , Sinergismo Farmacológico , Bacterias Gramnegativas , Pruebas de Sensibilidad Microbiana , Sulbactam , Tazobactam , Compuestos de Azabiciclo/farmacología , Tazobactam/farmacología , Sulbactam/farmacología , Cefalosporinas/farmacología , Antibacterianos/farmacología , Bacterias Gramnegativas/efectos de los fármacos , Carbapenémicos/farmacología , Humanos , Acinetobacter baumannii/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Inhibidores de beta-Lactamasas/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Combinación de Medicamentos

RESUMEN

BACKGROUND: Antibiotic resistance among Gram-negative bacteria in intensive care units (ICUs) is linked with high morbidity and mortality in patients. In this study, we estimated the therapeutic coverage of various antibiotics, focusing on cefiderocol and comparators, administered empirically against an infection of unknown origin in the ICU. METHODS: In the ARTEMIS surveillance study, susceptibilities of 624 Italian Gram-negative isolates to amikacin, aztreonam-avibactam, cefiderocol, ceftazidime-avibactam, ceftolozane-tazobactam, colistin, imipenem-relebactam, meropenem, and meropenem-vaborbactam were tested by broth microdilution, and results were interpreted by European Committee on Antimicrobial Susceptibility Testing breakpoints. The susceptibility rates from the ARTEMIS study were extrapolated to Gram-negative isolates obtained from 5,774 patients in Italian ICUs in 2021. The sum of the predicted susceptibilities of individual pathogens represented the overall likelihood of in vitro activity of each antibiotic as early targeted therapy for ICU patients. RESULTS: A total of 624 Italian Gram-negative isolates included 206 Pseudomonas aeruginosa, 138 Acinetobacter baumannii, 187 Klebsiella pneumoniae, and 93 Escherichia coli. Against A. baumannii, K. pneumoniae, P. aeruginosa, and E. coli, the overall susceptibility rates for cefiderocol were 87.7%, 96.8%, 99%, and 100%, respectively; and for comparator agents, 8.7-96.4%, 25.7-100%, 73.3-100%, and 89.2-100%, respectively. Among the subset of meropenem-resistant isolates, susceptibility rates of A. baumannii, K. pneumoniae, and P. aeruginosa to cefiderocol were 86.4%, 96.2% and 100%, respectively. Corresponding susceptibility rates to comparator agents were 0-96.8%, 0-100%, and 6.4-100%, respectively. There were no meropenem-resistant isolates of E. coli. The extrapolation of data to isolates from Italian ICUs showed that the highest likelihood of therapeutic coverage, both overall and among meropenem-resistant isolates, was reported for colistin (96.8% and 72.2%, respectively) and cefiderocol (95.7% and 71.4%, respectively). All other antibiotics were associated with a likelihood below 73% overall and between 0% and 41.4% for meropenem-resistant isolates. CONCLUSIONS: Based on confirmed susceptibility rates and reported ICU prevalence of multiple Gram-negative species, cefiderocol showed a higher predicted therapeutic coverage and utility in ICUs compared with comparator beta-lactam-beta-lactamase inhibitor antibiotics. Cefiderocol may be a promising early treatment option for patients at high risk of carbapenem-resistant Gram-negative bacterial infections in the ICU.

Asunto(s)

Antibacterianos , Carbapenémicos , Bacterias Gramnegativas , Infecciones por Bacterias Gramnegativas , Unidades de Cuidados Intensivos , Pruebas de Sensibilidad Microbiana , Humanos , Italia/epidemiología , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Infecciones por Bacterias Gramnegativas/tratamiento farmacológico , Infecciones por Bacterias Gramnegativas/microbiología , Infecciones por Bacterias Gramnegativas/epidemiología , Carbapenémicos/farmacología , Carbapenémicos/uso terapéutico , Bacterias Gramnegativas/efectos de los fármacos , Cefalosporinas/farmacología , Cefalosporinas/uso terapéutico , Klebsiella pneumoniae/efectos de los fármacos , Pseudomonas aeruginosa/efectos de los fármacos , Acinetobacter baumannii/efectos de los fármacos , Meropenem/farmacología , Meropenem/uso terapéutico , Farmacorresistencia Bacteriana Múltiple , Cefiderocol , Colistina/farmacología , Colistina/uso terapéutico