Acción Antibacteriana in vitro del Taraxacun officinale frente al Acinetobacter baumannii / In vitro Antibacterial Activity of Taraxacum officinale Against Acinetobacter baumannii / Ação antibacteriana in vitro de Taraxacum officinale contra Acinetobacter baumannii

Acinetobacter baumannii es una bacteria oportunista que representa un desafío significativo en el ámbito clínico debido a su rápida diseminación, elevada mortalidad y altos niveles de resistencia a los antimicrobianos convencionales. Esto ha impulsado la búsqueda de alternativas terapéuticas eficaces para el manejo de infecciones causadas por este patógeno. Objetivo: Evaluar la actividad antibacteriana in vitro del extracto de Taraxacum officinale (diente de león) frente a cepas de Acinetobacter baumannii. Materiales y Métodos: Se utilizaron cultivos in vitro con medio Muller Hinton y agar nutritivo para la activación y propagación de la cepa de referencia A. baumannii ATCC BAA-1605. Se obtuvo un extracto etanólico de T. officinale y se evaluaron diferentes concentraciones del mismo. Resultados: El extracto de T. officinale no mostró actividad antibacteriana significativa frente a. baumannii, ya que no se observó la formación de halos de inhibición, incluyendo en la prueba con el control positivo de Ciprofloxacina. Estos hallazgos llevaron a aceptar la hipótesis nula y rechazar la hipótesis alternativa, lo que sugiere una escasa eficacia del extracto de la planta frente a esta bacteria. Conclusiones: Se resalta la necesidad de realizar investigaciones más exhaustivas para comprender mejor los mecanismos de acción y la eficacia del extracto de T. officinale, así como explorar su potencial aplicación clínica en el tratamiento de infecciones causadas por A. baumannii dado que esta bacteria presenta altos niveles de resistencia a los antimicrobianos convencionales

Acinetobacter baumannii is an opportunistic bacteria that represents a significant challenge in the clinical field due to its rapid dissemination, high mortality, and high levels of resistance to conventional antimicrobials. This has driven the search for effective therapeutic alternatives for the management of infections caused by this pathogen. Objective: To evaluate the in vitro antibacterial activity of the Taraxacum officinale (dandelion) extract against Acinetobacter baumannii strains. Materials and Methods: In vitro cultures with Muller Hinton medium and nutrient agar were used for the activation and propagation of the reference strain A. baumannii ATCC BAA-1605. An ethanolic extract of T. officinale was obtained, and different concentrations of the extract were evaluated. Results: The T. officinale extract did not show significant antibacterial activity against A. baumannii, as no formation of inhibition halos was observed, including in the test with the positive control of Ciprofloxacin. These findings led to accepting the null hypothesis and rejecting the alternative hypothesis, suggesting a poor efficacy of the plant extract against this bacterium. Conclusions: The need to conduct more extensive research to better understand the mechanisms of action and the efficacy of the T. officinale extract is highlighted, as well as to explore its potential clinical application in the treatment of infections caused by A. baumannii, as this bacterium presents high levels of resistance to conventional antimicrobials.

Acinetobacter baumannii é uma bactéria oportunista que representa um desafio significativo no campo clínico devido à sua rápida disseminação, elevada mortalidade e altos níveis de resistência a antimicrobianos convencionais. Isso tem impulsionado a busca por alternativas terapêuticas eficazes para o manejo de infecções causadas por esse patógeno. Objetivo: Avaliar a atividade antibacteriana in vitro do extrato de Taraxacum officinale (dente-de-leão) contra cepas de Acinetobacter baumannii. Materiais e Métodos: Culturas in vitro com meio Muller Hinton e ágar nutritivo foram utilizadas para a ativação e propagação da cepa de referência A. baumannii ATCC BAA-1605. Um extrato etanólico de T. officinale foi obtido e diferentes concentrações do extrato foram avaliadas. Resultados: O extrato de T. officinale não mostrou atividade antibacteriana significativa contra A. baumannii, uma vez que não foi observada a formação de halos de inibição, incluindo no teste com o controle positivo de Ciprofloxacina. Esses achados levaram à aceitação da hipótese nula e rejeição da hipótese alternativa, sugerindo uma eficácia limitada do extrato da planta contra essa bactéria. Conclusões: Destaca-se a necessidade de realizar pesquisas mais amplas para compreender melhor os mecanismos de ação e a eficácia do extrato de T. officinale, bem como explorar sua potencial aplicação clínica no tratamento de infecções causadas por A. baumannii, uma vez que essa bactéria apresenta altos níveis de resistência a antimicrobianos convencionais.

Acción Antibacteriana in vitro del Taraxacun officinale frente al Acinetobacter baumannii

Acinetobacter baumannii es una bacteria oportunista que representa un desafío significativo en el ámbito clínico debido a su rápida diseminación, elevada mortalidad y altos niveles de resistencia a los antimicrobianos convencionales. Esto ha impulsado la búsqueda de alternativas terapéuticas eficaces para el manejo de infecciones causadas por este patógeno. Objetivo: Evaluar la actividad antibacteriana in vitro del extracto de Taraxacum officinale (diente de león) frente a cepas de Acinetobacter baumannii. Materiales y Métodos: Se utilizaron cultivos in vitro con medio Muller Hinton y agar nutritivo para la activación y propagación de la cepa de referencia A. baumannii ATCC BAA-1605. Se obtuvo un extracto etanólico de T. officinale y se evaluaron diferentes concentraciones del mismo. Resultados: El extracto de T. officinale no mostró actividad antibacteriana significativa frente a. baumannii, ya que no se observó la formación de halos de inhibición, incluyendo en la prueba con el control positivo de Ciprofloxacina. Estos hallazgos llevaron a aceptar la hipótesis nula y rechazar la hipótesis alternativa, lo que sugiere una escasa eficacia del extracto de la planta frente a esta bacteria. Conclusiones: Se resalta la necesidad de realizar investigaciones más exhaustivas para comprender mejor los mecanismos de acción y la eficacia del extracto de T. officinale, así como explorar su potencial aplicación clínica en el tratamiento de infecciones causadas por A. baumannii dado que esta bacteria presenta altos niveles de resistencia a los antimicrobianos convencionales.

Acinetobacter baumannii is an opportunistic bacteria that represents a significant challenge in the clinical field due to its rapid dissemination, high mortality, and high levels of resistance to conventional antimicrobials. This has driven the search for effective therapeutic alternatives for the management of infections caused by this pathogen. Objective: To evaluate the in vitro antibacterial activity of the Taraxacum officinale (dandelion) extract against Acinetobacter baumannii strains. Materials and Methods: In vitro cultures with Muller Hinton medium and nutrient agar were used for the activation and propagation of the reference strain A. baumannii ATCC BAA-1605. An ethanolic extract of T. officinale was obtained, and different concentrations of the extract were evaluated. Results: The T. officinale extract did not show significant antibacterial activity against A. baumannii, as no formation of inhibition halos was observed, including in the test with the positive control of Ciprofloxacin. These findings led to accepting the null hypothesis and rejecting the alternative hypothesis, suggesting a poor efficacy of the plant extract against this bacterium. Conclusions: The need to conduct more extensive research to better understand the mechanisms of action and the efficacy of the T. officinale extract is highlighted, as well as to explore its potential clinical application in the treatment of infections caused by A. baumannii, as this bacterium presents high levels of resistance to conventional antimicrobials.

Acinetobacter baumannii é uma bactéria oportunista que representa um desafio significativo no campo clínico devido à sua rápida disseminação, elevada mortalidade e altos níveis de resistência a antimicrobianos convencionais. Isso tem impulsionado a busca por alternativas terapêuticas eficazes para o manejo de infecções causadas por esse patógeno. Objetivo: Avaliar a atividade antibacteriana in vitro do extrato de Taraxacum officinale (dente-de-leão) contra cepas de Acinetobacter baumannii. Materiais e Métodos: Culturas in vitro com meio Muller Hinton e ágar nutritivo foram utilizadas para a ativação e propagação da cepa de referência A. baumannii ATCC BAA-1605. Um extrato etanólico de T. officinale foi obtido e diferentes concentrações do extrato foram avaliadas. Resultados: O extrato de T. officinale não mostrou atividade antibacteriana significativa contra A. baumannii, uma vez que não foi observada a formação de halos de inibição, incluindo no teste com o controle positivo de Ciprofloxacina. Esses achados levaram à aceitação da hipótese nula e rejeição da hipótese alternativa, sugerindo uma eficácia limitada do extrato da planta contra essa bactéria. Conclusões: Destaca-se a necessidade de realizar pesquisas mais amplas para compreender melhor os mecanismos de ação e a eficácia do extrato de T. officinale, bem como explorar sua potencial aplicação clínica no tratamento de infecções causadas por A. baumannii, uma vez que essa bactéria apresenta altos níveis de resistência a antimicrobianos convencionais.

Genomic study of Acinetobacter baumannii strains co-harboring bla OXA-58 and bla NDM-1 reveals a large multidrug-resistant plasmid encoding these carbapenemases in Brazil.

Introduction: Acinetobacter baumannii contributes significantly to the global issue of multidrug-resistant (MDR) nosocomial infections. Often, these strains demonstrate resistance to carbapenems (MDR-CRAB), the first-line treatment for infections instigated by MDR A. baumannii. Our study focused on the antimicrobial susceptibility and genomic sequences related to plasmids from 12 clinical isolates of A. baumannii that carry both the blaOXA-58 and bla NDM-1 carbapenemase genes. Methods: Whole-genome sequencing with long-read technology was employed for the characterization of an A. baumannii plasmid that harbors the bla OXA-58 and blaNDM-1 genes. The location of the bla OXA-58 and bla NDM-1 genes was confirmed through Southern blot hybridization assays. Antimicrobial susceptibility tests were conducted, and molecular characterization was performed using PCR and PFGE. Results: Multilocus Sequence Typing analysis revealed considerable genetic diversity among bla OXA-58 and bla NDM-1 positive strains in Brazil. It was confirmed that these genes were located on a plasmid larger than 300 kb in isolates from the same hospital, which also carry other antimicrobial resistance genes. Different genetic contexts were observed for the co-occurrence of these carbapenemase-encoding genes in Brazilian strains. Discussion: The propagation of bla OXA-58 and bla NDM-1 genes on the same plasmid, which also carries other resistance determinants, could potentially lead to the emergence of bacterial strains resistant to multiple classes of antimicrobials. Therefore, the characterization of these strains is of paramount importance for monitoring resistance evolution, curbing their rapid global dissemination, averting outbreaks, and optimizing therapy.

An outbreak of severe or lethal infections by a multidrug-resistant Acinetobacter baumannii ST126 strain carrying a plasmid with blaNDM-1 and blaOXA-58 carbapenemases.

Acinetobacter baumannii poses a significant health threat because of its frequent implications in hospital outbreaks and multidrug resistance (MDR). Here, we studied four A. baumannii isolates recovered during a hospital outbreak of severe or fatal cases to elucidate their diversity and factors contributing to their increased virulence and antibiotic resistance. The isolates were identified using MALDI-ToF and characterized using comparative genomics, PCR, and antimicrobial susceptibility tests. They were classified as ST126 and exhibited fewer than five chromosomal single-nucleotide variants and the same extrachromosomal content, indicating that they are a single strain (A. baumannii AB01). A. baumannii AB01 showed an MDR phenotype that could be linked to the carriage of parC and gyrA mutations, efflux transporters, aminoglycoside resistance genes, a class C beta-lactamase, and three carbapenemases, some of which are encoded on a 72 kb plasmid. ST126 is infrequent and has not been reported in Latin America, and our genomic data indicate a plausible origin for A. baumannii AB01 within the Pan Pacific region.

THE COMBINATORY EFFECTS OF ESSENTIAL OIL FROM Lippia macrophylla ON MULTIDRUG RESISTANT Acinetobacter baumannii CLINICAL ISOLATES.

To assess the antibacterial effectiveness of Lippia macrophylla essential oil (LMEO) against multidrug-resistant Acinetobacter baumannii isolates, both as a standalone treatment and in combination with conventional antibiotics. LMEO demonstrated a significant inhibitory effect on the growth of A. baumannii, with a minimum inhibitory concentration (MIC) below 500µg/mL. Notably, LMEO was capable of reversing the antibiotic resistance of clinical isolates or reducing their MIC values when used in combination with antibiotics, showing synergistic (FICI ≤ 0.5) or additive effects. The combination of LMEO and imipenem was particularly effective, displaying synergistic interactions for most isolates. Ultrastructural analyses supported these findings, revealing that the combination of LMEO + ceftazidime compromised the membrane integrity of the Acb35 isolate, leading to cytoplasmic leakage and increased formation of Outer Membrane Vesicles (OMVs). Taken together our results point for the use of LMEO alone or in combination as an antibacterial agent against A. baumannii. These findings offer promising avenues for utilizing LMEO as a novel antibacterial strategy against drug-resistant infections in healthcare settings, underscoring the potential of essential oils in enhancing antibiotic efficacy.

Inside-out, antimicrobial resistance mediated by efflux pumps in clinical strains of Acinetobacter baumannii isolated from burn wound infections.

Acinetobacter baumannii belongs to the ESKAPE group. It is classified as a critical priority group by the World Health Organization and a global concern on account of its capacity to acquire and develop resistance mechanisms to multiple antibiotics. Data from the United States indicates 500 deaths annually. Resistance mechanisms of this bacterium include enzymatic pathways such as ß-lactamases, carbapenemases, and aminoglycoside-modifying enzymes, decreased permeability, and overexpression of efflux pumps. A. baumannii has been demonstrated to possess efflux pumps, which are classified as members of the MATE family, RND and MFS superfamilies, and SMR transporters. The aim of our work was to assess the distribution of efflux pumps and their regulatory gene expression in clinical strains of A. baumannii isolated from burned patients. METHODS: From the Clinical Microbiology Laboratory at the Instituto Nacional de Rehabilitación Luis Guillermo Ibarra Ibarra collection in Mexico, 199 strains were selected. Antibiotics susceptibilities were performed by broth microdilutions to determine minimal inhibitory concentrations. Phenotypic assays with efflux pump inhibitors were conducted using carbonyl cyanide 3-chlorophenylhydrazone (CCCP) and phenylalanine-arginine ß-naphthylamide (PAßN) in conjunction with amikacin, ceftazidime, imipenem, meropenem and levofloxacin. A search was conducted for structural genes that are linked to efflux pumps, and the relative expression of the adeR, adeS, and adeL genes was analyzed. RESULTS: Among a total of 199 strains, 186 exhibited multidrug resistance (MDR). Fluoroquinolones demonstrated the highest resistance rates, while minocycline and amikacin displayed comparatively reduced resistance rates (1.5 and 28.1, respectively). The efflux activity of fluorquinolones exhibited the highest phenotypic detection (from 85 to 100%), while IMP demonstrated the lowest activity of 27% with PAßN and 43.3% with CCCP. Overexpression was observed in adeS and adeL, with adeR exhibiting overexpression. Concluding that clinical strains of A. baumannii from our institution exhibited efflux pumps as one of the resistance mechanisms.

Comparison of available methods to evaluate cefiderocol susceptibility in Acinetobacter spp.

Recently, considerable uncertainty has arisen concerning the appropriate susceptibility testing for cefiderocol in gram-negative bacilli, particularly in the context of its application to Acinetobacter spp. The optimal method for assessing the susceptibility levels of Acinetobacter spp. to cefiderocol remains a subject of debate due to substantial disparities observed in the values obtained through various testing procedures. This study employed four minimum inhibitory concentration (MIC) methodologies and the disk diffusion to assess the susceptibility of twenty-seven carbapenem resistant (CR)-Acinetobacter strains to cefiderocol. The results from our study reveal significant variations in the minimum inhibitory concentration (MIC) values obtained with the different methods and in the level of agreement in interpretation categories between the different MIC methods and the disk diffusion test. Among the MIC methods, there was relatively more consistency in reporting the interpretation categories. For European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints, the categorical agreement (CA) for MIC methods ranged between 66.7 and 81.5%. On the other hand, the essential agreement (EA) values were as low as 18.5-29.6%. The CA between MIC methods and disk diffusion was 81.5%. These results emphasize the need for a reliable, accurate, and clinically validated methodology to effectively assess the susceptibility of Acinetobacter spp. to cefiderocol. The wide variability observed in our study highlights the importance of standardizing the susceptibility testing process for cefiderocol to ensure consistent and reliable results for clinical decision-making.

Investigating the anti-growth, anti-resistance, and anti-virulence activities of Schoepfia schreberi J.F.Gmel. against the superbug Acinetobacter baumannii.

Schoepfia schreberi has been used in Mayan folk medicine to treat diarrhea and cough. This study aimed to determine the anti-growth, anti-resistance, and/or anti-virulence activities of S. schreberi extracts against Acinetobacter baumannii, a pathogen leader that causes healthcare-associated infections with high rates of drug-resistant including carbapenems, the last line of antibiotics known as superbugs, and analyze their composition using HPLC-DAD. Ethyl acetate (SSB-3) and methanol (SSB-4) bark extracts exhibit antimicrobial and biocidal effects against drug-susceptible and drug-resistant A. baumannii. Chemical analysis revealed that SSB-3 and SSB-4 contained of gallic and ellagic acids derivatives. The anti-resistance activity of the extracts revealed that SSB-3 or SSB-4, combined with imipenem, exhibited potent antibiotic reversal activity against A. baumannii by acting as pump efflux modulators. The extracts also displayed activity against surface motility of A. baumannii and its capacity to survive reactive oxygen species. This study suggests that S. schreberi can be considered a source of antibiotics, even adjuvanted compounds, as anti-resistant or anti-virulence agents against A. baumannii, contributing to ethnopharmacological knowledge and reappraisal of Mayan medicinal flora, and supporting the traditional use of the bark of the medicinal plant S. schreberi for the treatment of infectious diseases.

Hypothetical adhesin CAM87009.1 formulated in alum or biogenic silver nanoparticles protects mice from lethal infection by multidrug-resistant Acinetobacter baumannii.

Due to its antimicrobial resistance characteristics, the World Health Organization (WHO) classifies A. baumannii as one of the critical priority pathogens for the development of new therapeutic strategies. Vaccination has been approached as an interesting strategy to overcome the lack of effective antimicrobials and the long time required to develop and approve new drugs. In this study, we aimed to evaluate as a vaccine the hypothetical adhesin protein CAM87009.1 in its recombinant format (rCAM87009.1) associated with aluminum hydroxide (Alhydrogel®) or biogenic silver nanoparticles (bio-AgNP) as adjuvant components against lethal infection by A. baumannii MDR strain. Both vaccine formulations were administered in three doses intramuscularly in BALB/c murine models and the vaccinated animals were tested in a challenge assay with A. baumannii MDR strain (DL100). rCAM87009.1 protein associated with both adjuvants was able to protect 100 % of animals challenged with the lethal strain during the challenge period. After the euthanasia of the animals, no A. baumannii colonies were detected in the lungs of animals vaccinated with the rCAM87009.1 protein in both formulations. Since the first immunization, high IgG antibody titers were observed (1:819,200), with results being statistically similar in both vaccine formulations evaluated. rCAM87009.1 associated with both adjuvants was capable of inducing at least one class of isotypes associated with the processes of neutralization (IgG2b and IgA for bio-AgNP and Alhydrogel®, respectively), opsonization (IgG1 in both vaccines) and complement activation (IgM and IgG3 for bio-AgNP and Alhydrogel®, respectively). Furthermore, reduced tissue damage was observed in animals vaccinated with rCAM87009.1 + bio-AgNP when compared to animals vaccinated with Alhydrogel®. Our results indicate that the rCAM87009.1 protein associated with both bio-AgNP and Alhydrogel® are combinations capable of promoting immunity against infections caused by A. baumannii MDR. Additionally, we demonstrate the potential of silver nanoparticles as alternative adjuvant molecules to the use of aluminum salts.

Unsupervised learning and natural language processing highlight research trends in a superbug.

Introduction: Antibiotic-resistant Acinetobacter baumannii is a very important nosocomial pathogen worldwide. Thousands of studies have been conducted about this pathogen. However, there has not been any attempt to use all this information to highlight the research trends concerning this pathogen. Methods: Here we use unsupervised learning and natural language processing (NLP), two areas of Artificial Intelligence, to analyse the most extensive database of articles created (5,500+ articles, from 851 different journals, published over 3 decades). Results: K-means clustering found 113 theme clusters and these were defined with representative terms automatically obtained with topic modelling, summarising different research areas. The biggest clusters, all with over 100 articles, are biased toward multidrug resistance, carbapenem resistance, clinical treatment, and nosocomial infections. However, we also found that some research areas, such as ecology and non-human infections, have received very little attention. This approach allowed us to study research themes over time unveiling those of recent interest, such as the use of Cefiderocol (a recently approved antibiotic) against A. baumannii. Discussion: In a broader context, our results show that unsupervised learning, NLP and topic modelling can be used to describe and analyse the research themes for important infectious diseases. This strategy should be very useful to analyse other ESKAPE pathogens or any other pathogens relevant to Public Health.

Carbapenemase genes in clinical and environmental isolates of Acinetobacter spp. from Quito, Ecuador.

Carbapenem-resistant Acinetobacter spp. is associated with nosocomial infections in intensive care unit patients, resulting in high mortality. Although Acinetobacter spp. represent a serious public health problem worldwide, there are a few studies related to the presence of carbapenemases in health care facilities and other environmental settings in Ecuador. The main aim of this study was to characterize the carbapenem-resistant Acinetobacter spp. isolates obtained from four hospitals (52) and from five rivers (27) close to Quito. We used the disc diffusion and EDTA sinergy tests to determine the antimicrobial susceptibility and the production of metallo ß-lactamases, respectively. We carried out a multiplex PCR of gyrB gene and the sequencing of partial rpoB gene to bacterial species identification. We performed molecular screening of nine carbapenem-resistant genes (blaSPM, blaSIM, blaGIM, blaGES, blaOXA-23, blaOXA-24, blaOXA-51, blaOXA-58, and blaOXA-143) by multiplex PCR, followed by identification using sequencing of blaOXA genes. Our findings showed that carbapenem-resistant A. baumannii were the main species found in health care facilities and rivers. Most of the clinical isolates came from respiratory tract samples and harbored blaOXA-23, blaOXA-366, blaOXA-72, blaOXA-65, blaOXA-70, and blaOXA-143-like genes. The river isolates harbored only the blaOXA-51 and probably blaOXA-259 genes. We concluded that the most predominant type of carbapenem genes among isolates were both blaOXA-23 and blaOXA-65 among A. baumannii clinical isolates.

Acinetobacter baumannii, a Multidrug-Resistant Opportunistic Pathogen in New Habitats: A Systematic Review.

In recent years, humanity has begun to face a growing challenge posed by a rise in the prevalence of antibiotic-resistant bacteria. This has resulted in an alarming surge in fatalities and the emergence of increasingly hard-to-manage diseases. Acinetobacter baumannii can be seen as one of these resilient pathogens due to its increasing prevalence in hospitals, its resistance to treatment, and its association with elevated mortality rates. Despite its clinical significance, the scientific understanding of this pathogen in non-hospital settings remains limited. Knowledge of its virulence factors is also lacking. Therefore, in this review, we seek to shed light on the latest research regarding the ecological niches, microbiological traits, and antibiotic resistance profiles of Acinetobacter baumannii. Recent studies have revealed the presence of this bacterium in a growing range of environmental niches, including rivers, treatment plants, and soils. It has also been discovered in diverse food sources such as meat and vegetables, as well as in farm animals and household pets such as dogs and cats. This broader presence of Acinetobacter baumannii, i.e., outside of hospital environments, indicates a significant risk of environmental contamination. As a result, greater levels of awareness and new preventive measures should be promoted to address this potential threat to public health.

A bioinformatic approach to identify confirmed and probable CRISPR-Cas systems in the Acinetobacter calcoaceticus-Acinetobacter baumannii complex genomes.

Introduction: The Acinetobacter calcoaceticus-Acinetobacter baumannii complex, or Acb complex, consists of six species: Acinetobacter baumannii, Acinetobacter calcoaceticus, Acinetobacter nosocomialis, Acinetobacter pittii, Acinetobacter seifertii, and Acinetobacter lactucae. A. baumannii is the most clinically significant of these species and is frequently related to healthcare-associated infections (HCAIs). Clustered regularly interspaced short palindromic repeat (CRISPR) arrays and associated genes (cas) constitute bacterial adaptive immune systems and function as variable genetic elements. This study aimed to conduct a genomic analysis of Acb complex genomes available in databases to describe and characterize CRISPR systems and cas genes. Methods: Acb complex genomes available in the NCBI and BV-BRC databases, the identification and characterization of CRISPR-Cas systems were performed using CRISPRCasFinder, CRISPRminer, and CRISPRDetect. Sequence types (STs) were determined using the Oxford scheme and ribosomal multilocus sequence typing (rMLST). Prophages were identified using PHASTER and Prophage Hunter. Results: A total of 293 genomes representing six Acb species exhibited CRISPR-related sequences. These genomes originate from various sources, including clinical specimens, animals, medical devices, and environmental samples. Sequence typing identified 145 ribosomal multilocus sequence types (rSTs). CRISPR-Cas systems were confirmed in 26.3% of the genomes, classified as subtypes I-Fa, I-Fb and I-Fv. Probable CRISPR arrays and cas genes associated with CRISPR-Cas subtypes III-A, I-B, and III-B were also detected. Some of the CRISPR-Cas systems are associated with genomic regions related to Cap4 proteins, and toxin-antitoxin systems. Moreover, prophage sequences were prevalent in 68.9% of the genomes. Analysis revealed a connection between these prophages and CRISPR-Cas systems, indicating an ongoing arms race between the bacteria and their bacteriophages. Furthermore, proteins associated with anti-CRISPR systems, such as AcrF11 and AcrF7, were identified in the A. baumannii and A. pittii genomes. Discussion: This study elucidates CRISPR-Cas systems and defense mechanisms within the Acb complex, highlighting their diverse distribution and interactions with prophages and other genetic elements. This study also provides valuable insights into the evolution and adaptation of these microorganisms in various environments and clinical settings.

The extremophilic Andean isolate Acinetobacter sp. Ver3 expresses two ferredoxin-NADP+ reductase isoforms with different catalytic properties.

Ferredoxin/flavodoxin-NADPH reductases (FPRs) catalyze the reversible electron transfer between NADPH and ferredoxin/flavodoxin. The Acinetobacter sp. Ver3 isolated from high-altitude Andean lakes contains two isoenzymes, FPR1ver3 and FPR2ver3. Absorption spectra of these FPRs revealed typical features of flavoproteins, consistent with the use of FAD as a prosthetic group. Spectral differences indicate distinct electronic arrangements for the flavin in each enzyme. Steady-state kinetic measurements show that the enzymes display catalytic efficiencies in the order of 1-6 µm-1·s-1, although FPR1ver3 exhibited higher kcat values compared to FPR2ver3. When flavodoxinver3 was used as a substrate, both reductases exhibited dissimilar behavior. Moreover, only FPR1ver3 is induced by oxidative stimuli, indicating that the polyextremophile Ver3 has evolved diverse strategies to cope with oxidative environments.

Risk Factors Associated with Mortality in Acinetobacter baumannii Infections: Results of a Prospective Cohort Study in a Tertiary Public Hospital in Guayaquil, Ecuador.

Antibiotic overuse and the resulting antimicrobial resistance pose significant global public health challenges, providing an avenue for opportunistic pathogens like Acinetobacter baumannii to thrive. This study will report the trends of Acinetobacter baumannii antimicrobial resistance patterns at the Hospital Teodoro Maldonado Carbo, Ecuador. An observational, analytical, longitudinal, and prospective study was conducted involving patients diagnosed with hospital-acquired infections. Antimicrobial susceptibility testing was performed, followed by molecular analysis of carbapenemase genes in Acinetobacter baumannii isolates. We included 180 patients aged from 16 to 93 years. The hospital mortality rate was 63/180 (35%). Invasive mechanical ventilation (IMV) was indicated in 91/180 patients (50.4%). The overall survival (OS) rate in patients on IMV was 49.5% (45/91), with a median survival of 65 days. The OS rate in patients not on IMV was 80.9% (72/89), with a median survival of 106 days (HR 2.094; 95% CI 1.174-3.737; p = 0.012). From multivariate analysis, we conclude that ventilator-associated pneumonia is the most related factor to OS.

Identification and Clinical Characteristics of Community-Acquired Acinetobacter baumannii in Patients Hospitalized for Moderate or Severe COVID-19 in Peru.

Acinetobacter baumannii has been described as a cause of serious community-acquired infections in tropical countries. Currently, its implications when simultaneously identified with other pathogens are not yet adequately understood. A descriptive study was conducted on hospitalized patients with a diagnosis of moderate/severe SARS-CoV-2-induced pneumonia confirmed via real-time RT-PCR. Patients aged > 18 years who were admitted to a specialized COVID-19 treatment center in Peru were selected for enrollment. A. baumannii was detected via the PCR amplification of the blaOXA-51 gene obtained from nasopharyngeal swabs within 48 h of hospitalization. A total of 295 patients with COVID-19 who met the study inclusion criteria were enrolled. A. baumannii was simultaneously identified in 40/295 (13.5%) of COVID-19-hospitalized patients. Demographic data and comorbidities were comparable in both Acinetobacter-positive and -negative subgroups. However, patients identified as being infected with Acinetobacter were more likely to have received outpatient antibiotics prior to hospitalization, had a higher requirement for high-flow nasal cannula and a higher subjective incidence of fatigue, and were more likely to develop Acinetobacter-induced pneumonia during hospitalization. Conclusions: The group in which SARS-CoV-2 and A. baumannii were simultaneously identified had a higher proportion of fatigue, a higher frequency of requiring a high-flow cannula, and a higher proportion of superinfection with the same microorganism during hospitalization.

Treatment and Management of Acinetobacter Pneumonia: Lessons Learned from Recent World Event.

Acinetobacter pneumonia is a significant healthcare-associated infection that poses a considerable challenge to clinicians due to its multidrug-resistant nature. Recent world events, such as the COVID-19 pandemic, have highlighted the need for effective treatment and management strategies for Acinetobacter pneumonia. In this review, we discuss lessons learned from recent world events, particularly the COVID-19 pandemic, in the context of the treatment and management of Acinetobacter pneumonia. We performed an extensive literature review to uncover studies and information pertinent to the topic. The COVID-19 pandemic underscored the importance of infection control measures in healthcare settings, including proper hand hygiene, isolation protocols, and personal protective equipment use, to prevent the spread of multidrug-resistant pathogens like Acinetobacter. Additionally, the pandemic highlighted the crucial role of antimicrobial stewardship programs in optimizing antibiotic use and curbing the emergence of resistance. Advances in diagnostic techniques, such as rapid molecular testing, have also proven valuable in identifying Acinetobacter infections promptly. Furthermore, due to the limited availability of antibiotics for treating infections caused A. baumannii, alternative strategies are needed like the use of antimicrobial peptides, bacteriophages and their enzymes, nanoparticles, photodynamic and chelate therapy. Recent world events, particularly the COVID-19 pandemic, have provided valuable insights into the treatment and management of Acinetobacter pneumonia. These lessons emphasize the significance of infection control, antimicrobial stewardship, and early diagnostics in combating this challenging infection.

Antimicrobial activity of spiculisporic acid isolated from endophytic fungus Aspergillus cejpii of Hedera helix against MRSA.

The surge in multidrug-resistant pathogens worldwide has jeopardized the clinical efficiency of many current antibiotics. This problem steered many researchers in their quest to discover new effective antimicrobial agents from natural origins including plants or their residing endophytes. In this work, we aimed to identify the endophytic fungi derived from Hedera helix L. and investigate their potential antimicrobial activity. Bioguided fractionation approach was conducted to isolate the pure compounds from the most active fungal fraction. Out of a total of six different isolated endophytic fungal strains, only Aspergillus cejpii showed the highest activity against all tested microbial strains. The most active fraction was the dichloromethane/methanol fraction (DCM:MeOH), where it showed significant activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Serratia marcescens, Acinetobacter baumannii, Salmonella typhi, and three drug-resistant clinical isolate strains including Methicillin-resistant Staphylococcus aureus (MRSA, H1), Pseudomonas aeruginosa (PS 16), and Acinetobacter baumannii (ACT 322) using tetracyline and kanamycin as the control antibiotics. Bioguided fractionation of the active fraction led to the isolation of the γ-butenolide, spiculisporic acid. Structure elucidation was carried out using 1H and 13C-NMR spectroscopic analysis. The compound showed good antimicrobial activities with minimum inhibitory concentration (MIC) values ranging from 3.9 to 31.25 µg/mL against all tested strains. Gas chromatography coupled to mass spectrometry (GC-MS) profiling was also carried out to identify the metabolites in the microbial crude extract. In conclusion, endophytic fungi, Aspergillus cejpii, isolated from Hedera helix L. roots showed promising antimicrobial activity which merits further in-depth investigations for potential utilization as a source of new antibiotics in the future. It can also be considered as a novel source for spiculisporic acid.

Draft genome sequence of three hydrocarbon-degrading Pseudomonadota strains isolated from an abandoned century-old oil exploration well.

We present genome sequences of three Pseudomonadota strains isolated from an abandoned century-old oil exploration well. A Pseudomonas sp. genome showed a size of 5,378,420 bp, while Acinetobacter genomes sized 3,522,593 and 3,864,311 bp. Genomes included catabolic genes for benzoate, 4-hydroxybenzoate, salicylate, vanillate, indoleacetate, anthranilate, n-alkanes, 4-hydroxyphenylacetate, phenylacetate, among others.

Genomic features and comparative analysis of a multidrug-resistant Acinetobacter bereziniae strain infecting an animal: a novel emerging one health pathogen?

Acinetobacter bereziniae has recently gained medical notoriety due to its emergence as a multidrug resistance and healthcare-associated pathogen. In this study, we report the whole-genome characterization of an A. bereziniae strain (A321) recovered from an infected semiaquatic turtle, as well as a comparative analysis of A. bereziniae strains circulating at the human-animal-environment interface. Strain A321 displayed a multidrug resistance profile to medically important antimicrobials, which was supported by a wide resistome. The novel Tn5393m transposon and a qnrB19-bearing ColE1-like plasmid were identified in A321 strain. Novel OXA-229-like ß-lactamases were detected and expression of OXA-931 demonstrated a 2-64-fold increase in the minimum inhibitory concentration for ß-lactam agents. Comparative genomic analysis revealed that most A. bereziniae strains did not carry any antimicrobial resistance genes (ARGs); however, some strains from China, Brazil, and India harbored six or more ARGs. Furthermore, A. bereziniae strains harbored conserved virulence genes. These results add valuable information regarding the spread of ARGs and mobile genetic elements that could be shared not only between A. bereziniae but also by other bacteria of clinical interest. This study also demonstrates that A. bereziniae can spill over from anthropogenic sources into natural environments and subsequently be transmitted to non-human hosts, making this a potential One Health bacteria that require close surveillance.