RESUMEN

Acinetobacter lwoffii is widely considered to be a harmful bacterium that is resistant to medicines and disinfectants. A. lwoffii NL1 degrades phenols efficiently and shows promise as an aromatic compound degrader in antibiotic-contaminated environments. To gain a comprehensive understanding of A. lwoffii, the first genome-scale metabolic model of A. lwoffii was constructed using semi-automated and manual methods. The iNX811 model, which includes 811 genes, 1071 metabolites, and 1155 reactions, was validated using 39 unique carbon and nitrogen sources. Genes and metabolites critical for cell growth were analyzed, and 12 essential metabolites (mainly in the biosynthesis and metabolism of glycan, lysine, and cofactors) were identified as antibacterial drug targets. Moreover, to explore the metabolic response to phenols, metabolic flux was simulated by integrating transcriptomics, and the significantly changed metabolism mainly included central carbon metabolism, along with some transport reactions. In addition, the addition of substances that effectively improved phenol degradation was predicted and validated using the model. Overall, the reconstruction and analysis of model iNX811 helped to study the antimicrobial systems and biodegradation behavior of A. lwoffii.

Asunto(s)

Acinetobacter , Genoma Bacteriano , Acinetobacter/metabolismo , Acinetobacter/genética , Modelos Biológicos , Carbono/metabolismo , Redes y Vías Metabólicas , Nitrógeno/metabolismo , Fenoles/metabolismo , Biodegradación Ambiental , Antibacterianos/farmacología

RESUMEN

Microbial cells serve as efficient and environmentally friendly biocatalysts, but their stability and reusability in practical applications must often be improved through immobilization. Acinetobacter sp. Tol 5 shows high adhesiveness to materials due to its large cell surface protein AtaA, which consists of 3630 amino acids (aa). Previously, we developed a method for immobilizing bacteria using AtaA. Herein, we investigated the cell immobilization ability of in-frame deletion (IFD) mutants of AtaA with different sizes in Tol 5. Mini-AtaA, which consists of 775 aa and is functional in Escherichia coli, was produced and present on the cell surface; however, mini-AtaA showed no immobilization ability in Tol 5. A cell immobilization assay was performed with cells expressing 16 IFD mutants of AtaA with different sizes, revealing that a length of at least 1417 aa was required for the sufficient immobilization of Tol 5 cells; thus, the minimum length needed to achieve the adhesive function of AtaA varies among bacterial species. The constructed mutant library of AtaA ranging from 3630 to 775 aa will allow researchers to quickly and easily explore the optimal size of AtaA, even for bacteria newly introduced to AtaA.

Asunto(s)

Acinetobacter , Proteínas Bacterianas , Acinetobacter/genética , Acinetobacter/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Adhesión Bacteriana , Escherichia coli/genética , Escherichia coli/metabolismo , Células Inmovilizadas/metabolismo , Proteínas de la Membrana/metabolismo , Proteínas de la Membrana/genética

RESUMEN

This study provides an emended description of Acinetobacter faecalis, a species previously described based on a single isolate (YIM 103518T) from elephant feces in China. Our emended description is based on 15 novel isolates conspecific with the A. faecalis type strain, obtained from eight cattle farms in the Czech Republic. The A. faecalis strains have relatively small genomes (≈2.5-2.7 Mbp), with a GC content of 36.3-36.7 mol%. Core genome-based phylogenetic analysis showed that the 15 strains, together with the type strain of A. faecalis, form a distinct and internally coherent phylogroup within the genus. Pairwise genomic ANIb values for the 16 A. faecalis strains were 97.32-99.04 %, while ANIb values between the genomes of the 16 strains and those of the other Acinetobacter spp. were ≤ 86.2 %. Analysis of whole-cell MALDI-TOF mass spectra supported the distinctness and cohesiveness of the taxon. The A. faecalis strains could be differentiated from the other validly named Acinetobacter spp. by the absence of hemolytic activity along with their ability to grow at 37 °C and on L-aspartate, ethanol, and L-glutamate but not at 41 °C or on adipate or 2,3-butanediol. Reduced susceptibility to sulfamethoxazole, trimethoprim and/or streptomycin was shown in eight strains, along with the presence of corresponding antibiotic resistance genes. In conclusion, this study provides a comprehensive description of A. faecalis and demonstrates its occurrence in cattle feces. Though the ecological role of A. faecalis remains unknown, our results show its ability to acquire antibiotic resistance genes, likely as an adaptation to antibiotic selection pressure in livestock farms.

Asunto(s)

Antibacterianos , Heces , Filogenia , Animales , Bovinos/microbiología , Heces/microbiología , Antibacterianos/farmacología , Genoma Bacteriano/genética , República Checa , Acinetobacter/genética , Acinetobacter/clasificación , Acinetobacter/aislamiento & purificación , ADN Bacteriano/genética , Pruebas de Sensibilidad Microbiana , Composición de Base , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADN , Técnicas de Tipificación Bacteriana

RESUMEN

Dairy mastitis is one of the most common diseases in dairy farming, and the formation of pathogenic bacteria biofilms may be an important reason why traditional antibiotic therapy fails to resolve some cases of dairy mastitis. We isolated and identified three strains of A. lwoffii were with strong biofilm forming ability from dairy cow mastitis samples from Chongqing dairy farms in China. In order to investigate the effect of novel anti-biofilm peptide CRAMP-34 on A.lwoffii biofilms, the anti-biofilm effect was evaluated by crystal violet staining, biofilms viable bacteria counting and confocal laser scanning microscopy (CLSM). In addition, transcriptome sequencing analysis, qRT-PCR and phenotypic verification were used to explore the mechanism of its action. The results showed that CRAMP-34 had a dose-dependent eradicating effect on A. lwoffii biofilms. Transcriptome sequencing analysis showed that 36 differentially expressed genes (11 up-regulated and 25 down-regulated) were detected after the intervention with the sub-inhibitory concentration of CRAMP-34. These differentially expressed genes may be related to enzyme synthesis, fimbriae, iron uptake system, capsular polysaccharide and other virulence factors through the functional analysis of differential genes. The results of subsequent bacterial motility and adhesion tests showed that the motility of A.lwoffii were enhanced after the intervention of CRAMP-34, but there was no significant change in adhesion. It was speculated that CRAMP-34 may promote the dispersion of biofilm bacteria by enhancing the motility of biofilm bacteria, thereby achieving the effect of eradicating biofilms. Therefore, these results, along with our other previous findings, suggest that CRAMP-34 holds promise as a new biofilm eradicator and deserves further research and development.

Asunto(s)

Acinetobacter , Antibacterianos , Biopelículas , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Animales , Bovinos , Femenino , Acinetobacter/efectos de los fármacos , Acinetobacter/genética , Antibacterianos/farmacología , China , Mastitis Bovina/microbiología , Mastitis Bovina/tratamiento farmacológico , Adhesión Bacteriana/efectos de los fármacos , Perfilación de la Expresión Génica , Pruebas de Sensibilidad Microbiana , Infecciones por Acinetobacter/microbiología

RESUMEN

OBJECTIVE: The aim of this study was to investigate the characteristics and related functional pathways of the gut microbiota in patients with IgA nephropathy (IgAN) through metagenomic sequencing technology. METHODS: We enrolled individuals with primary IgAN, including patients with normal and abnormal renal function. Additionally, we recruited healthy volunteers as the healthy control group. Stool samples were collected, and species and functional annotation were performed through fecal metagenome sequencing. We employed linear discriminant analysis effect size (LEfSe) analysis to identify significantly different bacterial microbiota and functional pathways. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis was used to annotate microbiota functions, and redundancy analysis (RDA) was performed to analyze the factors affecting the composition and distribution of the gut microbiota. RESULTS: LEfSe analysis revealed differences in the gut microbiota between IgAN patients and healthy controls. The characteristic microorganisms in the IgAN group were classified as Escherichia coli, with a significantly greater abundance than that in the healthy control group (p < 0.05). The characteristic microorganisms in the IgAN group with abnormal renal function were identified as Enterococcaceae, Moraxella, Moraxella, and Acinetobacter. KEGG functional analysis demonstrated that the functional pathways of the microbiota that differed between IgAN patients and healthy controls were related primarily to bile acid metabolism. CONCLUSIONS: The status of the gut microbiota is closely associated not only with the onset of IgAN but also with the renal function of IgAN patients. The characteristic gut microbiota may serve as a promising diagnostic biomarker and therapeutic target for IgAN.

Asunto(s)

Heces , Microbioma Gastrointestinal , Glomerulonefritis por IGA , Metagenómica , Humanos , Glomerulonefritis por IGA/microbiología , Microbioma Gastrointestinal/genética , Masculino , Femenino , Adulto , Heces/microbiología , Metagenómica/métodos , Estudios de Casos y Controles , Persona de Mediana Edad , Moraxella/aislamiento & purificación , Moraxella/genética , Escherichia coli/aislamiento & purificación , Escherichia coli/genética , Acinetobacter/aislamiento & purificación , Acinetobacter/genética , Metagenoma , Adulto Joven

RESUMEN

A novel A. pittii J08 with heterotrophic nitrification and aerobic denitrification (HN-AD) isolated from pond sediments could rapidly degrade inorganic nitrogen (N) and total nitrogen (TN-N) with ammonium (NH4+-N) preference. N degradation rate of NH4+-N, nitrite (NO2--N) and nitrate (NO3--N) were 3.9 mgL-1h-1, 3.0 mgL-1h-1 and 2.7 mgL-1h-1, respectively. In addition, strain J08 could effectively utilize most of detected low-molecular-weight carbon (LMWC) sources to degrade inorganic N with a wide adaptability to various culture conditions. Whole genome sequencing (WGS) analysis revealed that assembled genome of stain J08 possessed the crucial genes involved in dissimilatory/assimilatory NO3--N reduction and NH4+-N assimilation. These results indicated that strain J08 could be applied to wastewater treatment in aquaculture.

Asunto(s)

Acinetobacter , Nitrógeno , Nitrógeno/metabolismo , Acinetobacter/metabolismo , Acinetobacter/genética , Genoma Bacteriano , Desnitrificación , Compuestos de Amonio/metabolismo , Genómica/métodos , Nitratos/metabolismo , Biodegradación Ambiental , Nitrificación , Nitritos/metabolismo , Filogenia , Aguas Residuales/microbiología , Secuenciación Completa del Genoma

RESUMEN

Prophages are prevalent among bacterial species, including strains carrying antibiotic resistance genes (ARGs). Prophage induction can be triggered by the SOS response to stressors, leading to cell lysis. In environments polluted by chemical stressors, ARGs and prophage co-harboring strains might pose an unknown risk of spreading ARGs through chemical pollutant-mediated prophage induction and subsequent cell lysis. In this study, we investigated the effects of common non-antibiotic water pollutants, triclosan and silver nanoparticles, on triggering prophage induction in clinical isolates carrying ARGs and the subsequent uptake of released ARGs by the naturally competent bacterium Acinetobacter baylyi. Our results demonstrate that both triclosan and silver nanoparticles, at environmentally relevant concentrations and those found in commercial products, significantly enhance prophage induction among various clinical isolates. Transmission electron microscopy imaging and plaque assays confirmed the production of infectious phage particles under non-antibiotic pollutants-mediated prophage induction. In addition, the rate of ARG transformation to A. baylyi significantly increased after the release of extracellular ARGs from prophage induction-mediated cell lysis. The mechanism of non-antibiotic pollutants-mediated prophage induction is primarily associated with excessive oxidative stress, which provokes the SOS response. Our findings offer insights into the role of non-antibiotic pollutants in promoting the dissemination of ARGs by triggering prophage induction.

Asunto(s)

Profagos , Profagos/genética , Acinetobacter/efectos de los fármacos , Acinetobacter/genética , Farmacorresistencia Microbiana/genética , Triclosán/farmacología , Farmacorresistencia Bacteriana/genética , Antibacterianos/farmacología , Nanopartículas del Metal , Plata/farmacología

RESUMEN

α,ω-Dicarboxylic acids, ω-aminoalkanoic acids, and α,ω-diaminoalkanes are valuable building blocks for the production of biopolyesters and biopolyamides. One of the key steps in producing these chemicals is the oxidation of ω-hydroxycarboxylic acids using alcohol dehydrogenases (e.g., ChnD of Acinetobacter sp. NCIMB 9871). However, the reaction and structural features of these enzymes remain mostly undiscovered. Thereby, we have investigated characteristics of ChnD based on enzyme kinetics, substrate-docking simulations, and mutation studies. Kinetic analysis revealed a distinct preference of ChnD for medium chain ω-hydroxycarboxylic acids, with the highest catalytic efficiency of 18.0 mM-1s-1 for 12-hydroxydodecanoic acid among C6 to C12 ω-hydroxycarboxylic acids. The high catalytic efficiency was attributed to the positive interactions between the carboxyl group of the substrates and the guanidino group of two arginine residues (i.e., Arg62 and Arg266) in the substrate binding site. The ChnD_R62L variant showed the increased efficiency and affinity, particularly for fatty alcohols (i.e., C6-C10) and branched-chain fatty alcohols, such as 3-methyl-2-buten-1-ol. Overall, this study contributes to the deeper understanding of medium-chain primary aliphatic alcohol dehydrogenases and their applications for the production of industrially relevant chemicals such as α,ω-dicarboxylic acids, ω-aminoalkanoic acids, and α,ω-diaminoalkanes from renewable biomass.

Asunto(s)

Acinetobacter , Acinetobacter/enzimología , Acinetobacter/genética , Especificidad por Sustrato , Cinética , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/química , Simulación del Acoplamiento Molecular , Oxidorreductasas de Alcohol/metabolismo , Oxidorreductasas de Alcohol/química , Oxidorreductasas de Alcohol/genética , Modelos Moleculares

RESUMEN

Non-baumannii Acinetobacter spp. are becoming more prevalent in clinical settings including those that present resistance to last-resort antibiotics such as colistin. AB222-IK40 is an Acinetobacter courvalinii strain isolated from the Ottawa Hospital Research Institute located in Ottawa, Canada. To our knowledge, it is the first report of clinical A. courvalinii in Canada. Based on the susceptibility profile, AB222-IK40 is resistant to colistin and non-susceptible to ertapenem. Whole-genome sequencing allowed for genomic investigation into colistin resistance mechanisms. No previously identified mechanism(s) were observed, but a mobile colistin resistance (mcr)-like gene and a UDP-glucose dehydrogenase gene were identified. Based on phylogenomic analyses, the mcr-like gene is an intrinsic phosphoethanolamine transferase. This gene family is implicated in one of the many mechanisms responsible for colistin resistance in Acinetobacter baumannii as well as Acinetobacter modestus. UDP-glucose dehydrogenase is involved in colistin resistance in Enterobacterales and has been shown to be involved in capsule formation in A. baumannii. Global lipidomics revealed greater abundance of phosphatidyl-myo-inositol and lyso-phosphatidyl ethanolamine moieties in the membrane of A. courvalinii than in A. baumannii. Lipidomic profiles showed differences that were probably responsible for the colistin resistance phenotype in AB222-IK40. This isolate was also hypervirulent based on survival assays in Galleria mellonella. As this is the first report of A. courvalinii from a hospital in Canada, this species may be an emerging clinical pathogen, and therefore, it is important to understand this mechanism of its colistin resistance and hypervirulence.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter , Antibacterianos , Colistina , Farmacorresistencia Bacteriana , Pruebas de Sensibilidad Microbiana , Colistina/farmacología , Infecciones por Acinetobacter/microbiología , Canadá , Humanos , Antibacterianos/farmacología , Acinetobacter/genética , Acinetobacter/efectos de los fármacos , Acinetobacter/aislamiento & purificación , Acinetobacter/clasificación , Farmacorresistencia Bacteriana/genética , Animales , Secuenciación Completa del Genoma , Filogenia , Virulencia/genética

RESUMEN

Pretreatment of lignocellulosic biomass produces growth inhibitory substances such as furfural which is toxic to microorganisms. Acinetobacter baylyi ADP1 cannot use furfural as a carbon source, instead it biotransforms this compound into difurfuryl ether using the reduced nicotinamide adenine dinucleotide (NADH)-dependent dehydrogenases AreB and FrmA during aerobic acetate catabolism. However, NADH consumption for furfural biotransformation compromises aerobic growth of A. baylyi ADP1. Depending on the growth phase, several genes related to acetate catabolism and oxidative phosphorylation changed their expression indicating that central metabolic pathways were affected by the presence of furfural. During the exponential growth phase, reactions involved in the formation of reduced nicotinamide adenine dinucleotide phosphate (NADPH) (icd gene) and NADH (sfcA gene) were preferred when furfural was present. Therefore a higher NADH and NADPH production might support furfural biotransformation and biomass production, respectively. In contrast, in the stationary growth phase genes of the glyoxylate shunt were overexpressed probably to save carbon compounds for biomass formation, and only NADH regeneration was appreciated. Finally, disruption of the frmA or areB gene in A. baylyi ADP1 led to a decrease in growth adaptation and in the capacity to biotransform furfural. The characterization of this physiological behavior clarifies the impact of furfural in Acinetobacter metabolism.

Asunto(s)

Acinetobacter , Furaldehído , Acinetobacter/genética , Acinetobacter/metabolismo , Acinetobacter/efectos de los fármacos , Acinetobacter/crecimiento & desarrollo , Furaldehído/metabolismo , Furaldehído/farmacología , NAD/metabolismo , Biotransformación , Regulación Bacteriana de la Expresión Génica , NADP/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Biomasa , Redes y Vías Metabólicas/genética

RESUMEN

BACKGROUND: Nasal colonization of two preterm infants in our neonatal ICU by Acinetobacter junii carrying the blaOXA-58 carbapenem resistance gene was demonstrated. OBJECTIVES: To study whether the two isolates were identical and to investigate the hypotheses of cross-transmission. METHODS: Antibiotic susceptibility tests of the two isolates were performed by standard diffusion and the MICs of carbapenems determined by the MIC-gradient strip method. The blaOXA-58 gene was detected by PCR. Isolates were compared using SNP analysis performed after WGS. The timelines of the two cases were determined based on the investigations and the study of the patients' records. RESULTS: The two isolates corresponded to the same strain, with case 1 being the index case, demonstrating cross-transmission to case 2. CONCLUSIONS: Acquisition of the strain was likely due to the recent carbapenem treatment of case 1 and cross-transmission due to the high amount of care administered to the two preterm infants. This is the first description of cross-transmission of A. junii carrying the blaOXA-58 gene.

Asunto(s)

Infecciones por Acinetobacter , Acinetobacter , Antibacterianos , Infección Hospitalaria , Unidades de Cuidado Intensivo Neonatal , beta-Lactamasas , Femenino , Humanos , Recién Nacido , Masculino , Acinetobacter/efectos de los fármacos , Acinetobacter/genética , Acinetobacter/aislamiento & purificación , Infecciones por Acinetobacter/microbiología , Antibacterianos/farmacología , beta-Lactamasas/genética , Carbapenémicos/farmacología , Infección Hospitalaria/microbiología , Recien Nacido Prematuro , Pruebas de Sensibilidad Microbiana , Polimorfismo de Nucleótido Simple

RESUMEN

The Type VI secretion system (T6SS) is a multicomponent apparatus, present in many Gram-negative bacteria, which can inhibit bacterial prey in various ecological niches. Pseudomonas aeruginosa assembles one of its three T6SS (H1-T6SS) to respond to attacks from adjacent competing bacteria. Surprisingly, repeated assemblies of the H1-T6SS, termed dueling, were described in a monoculture in the absence of an attacker strain; however, the underlying mechanism was unknown. Here, we explored the role of H2-T6SS of P. aeruginosa in triggering H1-T6SS assembly. We show that H2-T6SS inactivation in P. aeruginosa causes a significant reduction in H1-T6SS dueling and that H2-T6SS activity directly triggers retaliation by the H1-T6SS. Intraspecific competition experiments revealed that elimination of H2-T6SS in non-immune prey cells conferred protection from H1-T6SS. Moreover, we show that the H1-T6SS response is triggered independently of the characterized lipase effectors of the H2-T6SS, as well as those of Acinetobacter baylyi and Vibrio cholerae. Our results suggest that H1-T6SS response to H2-T6SS in P. aeruginosa can impact intraspecific competition, particularly when the H1-T6SS effector-immunity pairs differ between strains, and could determine the outcome of multistrain colonization.IMPORTANCEThe opportunistic pathogen Pseudomonas aeruginosa harbors three different Type VI secretion systems (H1, H2, and H3-T6SS), which can translocate toxins that can inhibit bacterial competitors or inflict damage to eukaryotic host cells. Unlike the unregulated T6SS assembly in other Gram-negative bacteria, the H1-T6SS in P. aeruginosa is precisely assembled as a response to various cell damaging attacks from neighboring bacterial cells. Surprisingly, it was observed that neighboring P. aeruginosa cells repeatedly assemble their H1-T6SS toward each other. Mechanisms triggering this "dueling" behavior between sister cells were unknown. In this report, we used a combination of microscopy, genetic and intraspecific competition experiments to show that H2-T6SS initiates H1-T6SS dueling. Our study highlights the interplay between different T6SS clusters in P. aeruginosa, which may influence the outcomes of multistrain competition in various ecological settings such as biofilm formation and colonization of cystic fibrosis lungs.

Asunto(s)

Pseudomonas aeruginosa , Sistemas de Secreción Tipo VI , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/metabolismo , Pseudomonas aeruginosa/fisiología , Sistemas de Secreción Tipo VI/metabolismo , Sistemas de Secreción Tipo VI/genética , Acinetobacter/genética , Acinetobacter/metabolismo , Acinetobacter/fisiología , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Vibrio cholerae/genética , Vibrio cholerae/fisiología , Vibrio cholerae/metabolismo , Interacciones Microbianas

RESUMEN

To investigate the inhibitory effects of various transition metal ions on nitrogen removal and their underlying mechanisms, the single and combined effects of Cu2+ Ni2+ and Zn2+ on Heterotrophic nitrification-aerobic denitrification (HN-AD) bacteria Acinetobacter sp. TAC-1 were studied in a batch experiment system. The results revealed that increasing concentrations of Cu2+ and Ni2+ had a detrimental effect on the removal of ammonium nitrogen (NH4+-N) and total nitrogen (TN). Specifically, Cu2+ concentration of 10 mg/L, the TN degradation rate was 55.09%, compared to 77.60% in the control group. Cu2+ exhibited a pronounced inhibitory effect. In contrast, Zn2+ showed no apparent inhibitory effect on NH4+-N removal and even enhanced TN removal at lower concentrations. However, when the mixed ion concentration of Zn2++Ni2+ exceeded 5 mg/L, the removal rates of NH4+-N and TN were significantly reduced. Moreover, transition metal ions did not significantly impact the removal rates of chemical oxygen demand (COD). The inhibition model fitting results indicated that the inhibition sequence was Cu2+ > Zn2+ > Ni2+. Transcriptome analysis demonstrated that metal ions influence TAC-1 activity by modulating the expression of pivotal genes, including zinc ABC transporter substrate binding protein (znuA), ribosomal protein (rpsM), and chromosome replication initiation protein (dnaA) and DNA replication of TAC-1 under metal ion stress, leading to disruptions in transcription, translation, and cell membrane structure. Finally, a conceptual model was proposed by us to summarize the inhibition mechanism and possible response strategies of TAC-1 bacteria under metal ion stress, and to address the lack of understanding regarding the influence mechanism of TAC-1 on nitrogen removal in wastewater co-polluted by metal and ammonia nitrogen. The results provided practical guidance for the management of transition metal and ammonia nitrogen co-polluted water bodies, as well as the removal of high nitrogen.

Asunto(s)

Desnitrificación , Nitrificación , Acinetobacter/metabolismo , Acinetobacter/genética , Procesos Heterotróficos , Aerobiosis , Elementos de Transición/metabolismo , Nitrógeno/metabolismo , Contaminantes Químicos del Agua/metabolismo

RESUMEN

Improved and contemporary agriculture relies heavily on pesticides, yet some can be quite persistent and have a stable chemical composition, posing a significant threat to the ecology. Removing harmful effects is upon their degradability. Biodegradation must be emphasized to lower pesticide degradation costs, especially in the soil. Here, a decision-making system was used to determine the best microbial strain for the biodegradation of the pyrethroid-contaminated soil. In this system, the criteria chosen as: pH (C1), Temp (C2), RPM (C3), Conc. (C4), Degradation (%) (C5) and Time required for degradation(hrs) (C6); and five alternatives were Bacillus (A1), Acinetobacter (A2), Escherichia (A3), Pseudomonas (A4), and Fusarium (A5). The best alternative was selected by applying the TOPSIS (technique for order performance by similarity to ideal solution) method, which evaluates based on their closeness to the ideal solution and how well they meet specific requirements. Among all the specified criteria, Acinetobacter (A2) was the best and optimal based on the relative closeness value (( R i ∗ ) = 0.740 (A2) > 0.544 (A5) > 0.480 (A1) > 0.403 (A4) > 0.296 (A3)). However, the ranking of the other alternatives is also obtained in the order Fusarium (A5), Bacillus (A1), Pseudomonas (A4), Escherichia (A3). Hence this study suggests Acinetobacter is the best microbial strain for biodegradation of pyrethroids; while least preference should be given to Escherichia. Acinetobacter, versatile metabolic nature with various xenobiotic compounds' degradation ability, is gram-negative, aerobic, coccobacilli, nonmotile, and nonspore forming bacteria. Due to less study about Acinetobacter it is not in that much frame as the other microorganisms. Hence, considering the Acinetobacter strain for the biodegradation study will give more optimal results than the other microbial strains. Novelty of this study, the TOPSIS method is applied first time in selecting the best microbial strain for the biodegradation of pyrethroid-contaminated soil, considering this selection process as multi-criteria decision-making (MCDM) problem.

Asunto(s)

Biodegradación Ambiental , Piretrinas , Microbiología del Suelo , Contaminantes del Suelo , Piretrinas/metabolismo , Contaminantes del Suelo/metabolismo , Bacterias/metabolismo , Bacterias/genética , Bacterias/clasificación , Bacillus/metabolismo , Bacillus/genética , Fusarium/metabolismo , Toma de Decisiones , Pseudomonas/metabolismo , Pseudomonas/genética , Acinetobacter/metabolismo , Acinetobacter/genética

RESUMEN

BACKGROUND: Acinetobacter lwoffii (A. lwoffii) is a Gram-negative bacteria common in the environment, and it is the normal flora in human respiratory and digestive tracts. The bacteria is a zoonotic and opportunistic pathogen that causes various infections, including nosocomial infections. The aim of this study was to identify A. lwoffii strains isolated from bovine milk with subclinical mastitis in China and get a better understanding of its antimicrobial susceptibility and resistance profile. This is the first study to analyze the drug resistance spectrum and corresponding mechanisms of A. lwoffii isolated in raw milk. RESULTS: Four A. lwoffii strains were isolated by PCR method. Genetic evolution analysis using the neighbor-joining method showed that the four strains had a high homology with Acinetobacter lwoffii. The strains were resistant to several antibiotics and carried 17 drug-resistance genes across them. Specifically, among 23 antibiotics, the strains were completely susceptible to 6 antibiotics, including doxycycline, erythromycin, polymyxin, clindamycin, imipenem, and meropenem. In addition, the strains showed variable resistance patterns. A total of 17 resistance genes, including plasmid-mediated resistance genes, were detected across the four strains. These genes mediated resistance to 5 classes of antimicrobials, including beta-lactam, aminoglycosides, fluoroquinolones, tetracycline, sulfonamides, and chloramphenicol. CONCLUSION: These findings indicated that multi-drug resistant Acinetobacter lwoffii strains exist in raw milk of bovine with subclinical mastitis. Acinetobacter lwoffii are widespread in natural environmental samples, including water, soil, bathtub, soap box, skin, pharynx, conjunctiva, saliva, gastrointestinal tract, and vaginal secretions. The strains carry resistance genes in mobile genetic elements to enhance the spread of these genes. Therefore, more attention should be paid to epidemiological surveillance and drug resistant A. lwoffii.

Asunto(s)

Acinetobacter , Antibacterianos , Mastitis Bovina , Leche , Animales , Bovinos , Mastitis Bovina/microbiología , Mastitis Bovina/epidemiología , Femenino , Acinetobacter/aislamiento & purificación , Acinetobacter/genética , Acinetobacter/efectos de los fármacos , Leche/microbiología , China/epidemiología , Antibacterianos/farmacología , Pruebas de Sensibilidad Microbiana/veterinaria , Infecciones por Acinetobacter/veterinaria , Infecciones por Acinetobacter/microbiología , Infecciones por Acinetobacter/epidemiología , Farmacorresistencia Bacteriana/genética , Farmacorresistencia Bacteriana Múltiple/genética

RESUMEN

Antimicrobial-resistance genes (ARGs) are spread among bacteria by horizontal gene transfer, however, the effect of environmental factors on the dynamics of the ARG in water environments has not been very well understood. In this systematic review, we employed the regression tree algorithm to identify the environmental factors that facilitate/inhibit the transfer of ARGs via conjugation in planktonic/biofilm-formed bacterial cells based on the results of past relevant research. Escherichia coli strains were the most studied genus for conjugation experiments as donor/recipient in the intra-genera category. Conversely, Pseudomonas spp., Acinetobacter spp., and Salmonella spp. were studied primarily as recipients across inter-genera bacteria. The conjugation efficiency (ce) was found to be highly dependent on the incubation period. Some antibiotics, such as nitrofurantoin (at ≥0.2 µg ml-1) and kanamycin (at ≥9.5 mg l-1) as well as metallic compounds like mercury (II) chloride (HgCl2, ≥3 µmol l-1), and vanadium (III) chloride (VCl3, ≥50 µmol l-1) had enhancing effect on conjugation. The highest ce value (-0.90 log10) was achieved at 15°C-19°C, with linoleic acid concentrations <8 mg l-1, a recognized conjugation inhibitor. Identifying critical environmental factors affecting ARG dissemination in aquatic environments will accelerate strategies to control their proliferation and combat antibiotic resistance.

Asunto(s)

Antibacterianos , Bacterias , Conjugación Genética , Farmacorresistencia Bacteriana , Transferencia de Gen Horizontal , Antibacterianos/farmacología , Bacterias/genética , Bacterias/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Microbiología del Agua , Escherichia coli/genética , Escherichia coli/efectos de los fármacos , Genes Bacterianos , Acinetobacter/genética , Acinetobacter/efectos de los fármacos , Biopelículas/efectos de los fármacos

RESUMEN

This study aimed to characterize the composition of intestinal and nasal microbiota in septic patients and identify potential microbial biomarkers for diagnosis. A total of 157 subjects, including 89 with sepsis, were enrolled from the affiliated hospital. Nasal swabs and fecal specimens were collected from septic and non-septic patients in the intensive care unit (ICU) and Department of Respiratory and Critical Care Medicine. DNA was extracted, and the V4 region of the 16S rRNA gene was amplified and sequenced using Illumina technology. Bioinformatics analysis, statistical processing, and machine learning techniques were employed to differentiate between septic and non-septic patients. The nasal microbiota of septic patients exhibited significantly lower community richness (P = 0.002) and distinct compositions (P = 0.001) compared to non-septic patients. Corynebacterium, Staphylococcus, Acinetobacter, and Pseudomonas were identified as enriched genera in the nasal microbiota of septic patients. The constructed machine learning model achieved an area under the curve (AUC) of 89.08, indicating its efficacy in differentiating septic and non-septic patients. Importantly, model validation demonstrated the effectiveness of the nasal microecological diagnosis prediction model with an AUC of 84.79, while the gut microecological diagnosis prediction model had poor predictive performance (AUC = 49.24). The nasal microbiota of ICU patients effectively distinguishes sepsis from non-septic cases and outperforms the gut microbiota. These findings have implications for the development of diagnostic strategies and advancements in critical care medicine.IMPORTANCEThe important clinical significance of this study is that it compared the intestinal and nasal microbiota of sepsis with non-sepsis patients and determined that the nasal microbiota is more effective than the intestinal microbiota in distinguishing patients with sepsis from those without sepsis, based on the difference in the lines of nasal specimens collected.

Asunto(s)

Bacterias , Biomarcadores , Heces , Unidades de Cuidados Intensivos , Microbiota , ARN Ribosómico 16S , Sepsis , Humanos , Sepsis/diagnóstico , Sepsis/microbiología , Masculino , Femenino , Persona de Mediana Edad , Anciano , ARN Ribosómico 16S/genética , Biomarcadores/análisis , Bacterias/aislamiento & purificación , Bacterias/genética , Bacterias/clasificación , Heces/microbiología , Adulto , Aprendizaje Automático , Microbioma Gastrointestinal , Nariz/microbiología , Corynebacterium/aislamiento & purificación , Corynebacterium/genética , Acinetobacter/aislamiento & purificación , Acinetobacter/genética , Anciano de 80 o más Años , Staphylococcus/aislamiento & purificación , Staphylococcus/genética , Pseudomonas/aislamiento & purificación , Pseudomonas/genética

RESUMEN

Pathogenic bacteria of the Acinetobacter genus pose a severe threat to human health worldwide due to their strong adaptability, tolerance, and antibiotic resistance. Most isolates of these bacteria harbor a type VI secretion system (T6SS) that allows them to outcompete co-residing microorganisms, but whether this system is involved in acquiring nutrients from preys remains less studied. In this study, we found that Ab25, a clinical isolate of Acinetobacter nosocomialis, utilizes a T6SS to kill taxonomically diverse microorganisms, including bacteria and fungi. The T6SS of Ab25 is constitutively expressed, and among the three predicted effectors, T6e1, a member of the RHS effector family, contributes the most for its antimicrobial activity. T6e1 undergoes self-cleavage, and a short carboxyl fragment with nuclease activity is sufficient to kill target cells via T6SS injection. Interestingly, strain Ab25 encodes an orphan VgrG protein, which when overexpressed blocks the firing of its T6SS. In niches such as dry plastic surfaces, the T6SS promotes prey microorganism-dependent survival of Ab25. These results reveal that A. nosocomialis employs T6SSs that are highly diverse in their regulation and effector composition to gain a competitive advantage in environments with scarce nutrient supply and competing microbes.IMPORTANCEThe type VI secretion system (T6SS) plays an important role in bacterial adaptation to environmental challenges. Members of the Acinetobacter genus, particularly A. baumannii and A. nosocomialis, are notorious for their multidrug resistance and their ability to survive in harsh environments. In contrast to A. baumannii, whose T6SS has been well-studied, few research works have focused on A. nosocomialis. In this study, we found that an A. nosocomialis strain utilizes a contitutively active T6SS to kill diverse microorganisms, including bacteria and fungi. Although T6SS structural proteins of A. nosocomialis are similar to those of A. baumannii, the effector repertoire differs greatly. Interestingly, the T6SS of the A. nosocomialis strain codes for an ophan VgrG protein, which blocks the firing of the system when overexpressed, suggesting the existence of a new regulatory mechanism for the T6SS. Importantly, although the T6SS does not provide an advantage when the bacterium is grown in nutrient-rich medium, it allows A. nosocomialis to survive better in dry surfaces that contain co-existing bacteria. Our results suggest that killing of co-residing microorganisms may increase the effectiveness of strategies designed to reduce the fitness of Acinetobacter bacteria by targeting their T6SS.

Asunto(s)

Acinetobacter , Sistemas de Secreción Tipo VI , Sistemas de Secreción Tipo VI/metabolismo , Sistemas de Secreción Tipo VI/genética , Acinetobacter/genética , Acinetobacter/metabolismo , Acinetobacter/fisiología , Proteínas Bacterianas/metabolismo , Proteínas Bacterianas/genética , Infecciones por Acinetobacter/microbiología , Humanos , Viabilidad Microbiana , Hongos/genética , Hongos/metabolismo , Hongos/fisiología

RESUMEN

Corynebacterium glutamicum ATCC 13032 is a promising microbial chassis for industrial production of valuable compounds, including aromatic amino acids derived from the shikimate pathway. In this work, we developed two whole-cell, transcription factor based fluorescent biosensors to track cis,cis-muconic acid (ccMA) and chorismate in C. glutamicum. Chorismate is a key intermediate in the shikimate pathway from which value-added chemicals can be produced, and a shunt from the shikimate pathway can divert carbon to ccMA, a high value chemical. We transferred a ccMA-inducible transcription factor, CatM, from Acinetobacter baylyi ADP1 into C. glutamicum and screened a promoter library to isolate variants with high sensitivity and dynamic range to ccMA by providing benzoate, which is converted to ccMA intracellularly. The biosensor also detected exogenously supplied ccMA, suggesting the presence of a putative ccMA transporter in C. glutamicum, though the external ccMA concentration threshold to elicit a response was 100-fold higher than the concentration of benzoate required to do so through intracellular ccMA production. We then developed a chorismate biosensor, in which a chorismate inducible promoter regulated by natively expressed QsuR was optimized to exhibit a dose-dependent response to exogenously supplemented quinate (a chorismate precursor). A chorismate-pyruvate lyase encoding gene, ubiC, was introduced into C. glutamicum to lower the intracellular chorismate pool, which resulted in loss of dose dependence to quinate. Further, a knockout strain that blocked the conversion of quinate to chorismate also resulted in absence of dose dependence to quinate, validating that the chorismate biosensor is specific to intracellular chorismate pool. The ccMA and chorismate biosensors were dually inserted into C. glutamicum to simultaneously detect intracellularly produced chorismate and ccMA. Biosensors, such as those developed in this study, can be applied in C. glutamicum for multiplex sensing to expedite pathway design and optimization through metabolic engineering in this promising chassis organism. ONE-SENTENCE SUMMARY: High-throughput screening of promoter libraries in Corynebacterium glutamicum to establish transcription factor based biosensors for key metabolic intermediates in shikimate and ß-ketoadipate pathways.

Asunto(s)

Técnicas Biosensibles , Ácido Corísmico , Corynebacterium glutamicum , Ácido Sórbico , Corynebacterium glutamicum/metabolismo , Corynebacterium glutamicum/genética , Técnicas Biosensibles/métodos , Ácido Sórbico/metabolismo , Ácido Sórbico/análogos & derivados , Ácido Corísmico/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Regiones Promotoras Genéticas , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Acinetobacter/metabolismo , Acinetobacter/genética

RESUMEN

The effects of antibiotics, such as tetracycline, sulfamethoxazole, and ciprofloxacin, on functional microorganisms are of significant concern in wastewater treatment. This study observed that Acinetobacter indicus CZH-5 has a limited capacity to remove nitrogen and phosphorus using antibiotics (5 mg/L) as the sole carbon source. When sodium acetate was supplied (carbon/nitrogen ratio = 7), the average removal efficiencies of ammonia-N, total nitrogen, and orthophosphate-P increased to 52.46 %, 51.95 %, and 92.43 %, respectively. The average removal efficiencies of antibiotics were 84.85 % for tetracycline, 39.32 % for sulfamethoxazole, 18.85 % for ciprofloxacin, and 23.24 % for their mixtures. Increasing the carbon/nitrogen ratio to 20 further improved the average removal efficiencies to 72.61 % for total nitrogen and 97.62 % for orthophosphate-P (5 mg/L antibiotics). Additionally, the growth rate and pollutant removal by CZH-5 were unaffected by the presence of 0.1-1 mg/L antibiotics. Transcriptomic analysis revealed that the promoted translation of aceE, aarA, and gltA genes provided ATP and proton -motive forces. The nitrogen metabolism and polyphosphate genes were also affected. The expression of acetate kinase, dehydrogenase, flavin mononucleotide enzymes, and cytochrome P450 contributed to antibiotic degradation. Intermediate metabolites were investigated to determine the reaction pathways.

Asunto(s)

Acinetobacter , Antibacterianos , Nitrógeno , Fósforo , Contaminantes Químicos del Agua , Nitrógeno/metabolismo , Fósforo/metabolismo , Acinetobacter/metabolismo , Acinetobacter/genética , Acinetobacter/efectos de los fármacos , Contaminantes Químicos del Agua/metabolismo , Aerobiosis , Biodegradación Ambiental , Eliminación de Residuos Líquidos/métodos , Aguas Residuales