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International Journal of Molecular... Nov 2023Microorganism-based methods have been widely applied for the treatment of phenol-polluted environments. The previously isolated NL1 strain could completely degrade 0.5...
Microorganism-based methods have been widely applied for the treatment of phenol-polluted environments. The previously isolated NL1 strain could completely degrade 0.5 g/L phenol within 12 h, but not higher concentrations of phenol. In this study, we developed an evolutionary strain NL115, through adaptive laboratory evolution, which possessed improved degradation ability and was able to degrade 1.5 g/L phenol within 12 h. Compared with that of the starting strain NL1, the concentration of degradable phenol by the developed strain increased three-fold; its phenol tolerance was also enhanced. Furthermore, comparative genomics showed that sense mutations mainly occurred in genes encoding alkyl hydroperoxide reductase, phenol hydroxylase, 30S ribosomal protein, and mercury resistance operon. Comparative transcriptomics between NL115 and NL1 revealed the enrichment of direct degradation, stress resistance, and vital activity processes among the metabolic responses of adapted to phenol stress. Among these, all the upregulated genes (logfold-change > 5) encoded peroxidases. A phenotypic comparison of NL1 and NL115 found that the adapted strain NL115 exhibited strengthened antioxidant capacity. Furthermore, the increased enzymatic activities of phenol hydroxylase and alkyl hydroperoxide reductase in NL115 validated their response to phenol. Overall, this study provides insight into the mechanism of efficient phenol degradation through adaptive microbial evolution and can help to drive improvements in phenol bioremediation.
Topics: Transcriptome; Phenols; Phenol; Biodegradation, Environmental; Genomics; Peroxiredoxins
PubMed: 38003719
DOI: 10.3390/ijms242216529 -
International Microbiology : the... Nov 2023Ingesting marine plastics is increasingly common in cetaceans, but little is known about their potential effects. Here, by utilizing 16S rRNA gene sequencing, we...
Ingesting marine plastics is increasingly common in cetaceans, but little is known about their potential effects. Here, by utilizing 16S rRNA gene sequencing, we profiled the intestinal bacterial communities of a stranded Risso's dolphin (Grampus griseus) which died because of the ingestion of rubber gloves. In this study, we explored the potential relationships between starvation raised by plastic ingestion with the dolphin gut microbiota. Our results showed significant differences in bacterial diversity and composition among the different anatomical areas along the intestinal tract, which may be related to the intestinal emptying process under starvation. In addition, the intestinal bacterial composition of the Risso's dolphin showed both similarity and divergence to that of other toothed whales, suggesting potential roles of both host phylogeny and habitat shaping of the cetacean intestinal microbiome. Perhaps, the microbiota is reflecting a potentially disordered intestinal microbial profile caused by the ingestion of macro-plastics which led to starvation. Moreover, two operational taxonomic units (0.17% of the total reads) affiliated with Actinobacillus and Acinetobacter lwoffii were detected along the intestinal tract. These bacterial species may cause infections in immunocompromised dolphins which are malnourished. This preliminary study profiles the intestinal microbiota of a Risso's dolphin, and provides an additional understanding of the potential relationships between starvation raised by ingesting macro-plastics with cetacean gut microbiota.
Topics: Animals; Dolphins; Gastrointestinal Microbiome; RNA, Ribosomal, 16S; Eating
PubMed: 37059916
DOI: 10.1007/s10123-023-00355-z -
Fukushima Journal of Medical Science Nov 2023The incidence of Acinetobacter infections has increased in recent years. Acinetobacter infections are resistant to most antibiotics and can be found in hospitalized...
The incidence of Acinetobacter infections has increased in recent years. Acinetobacter infections are resistant to most antibiotics and can be found in hospitalized patients. Pregnancies complicated by severe sepsis or septic shock are associated with a higher rate of preterm labor and delivery, fetal infection, and operative delivery. This case report describes septic shock due to Acinetobacter lwoffii infection in the 31st week of gestation. A 47-year-old woman, with a gestation of 31 weeks and one day, presented with a fever, and signs of bacterial infection on laboratory tests. Although the patient was started on tazobactam/piperacillin, she went into septic shock, and was transferred to our hospital. Cesarean section was performed at a gestation of 31 weeks and 4 days because of severe maternal pneumonia and non-reassuring fetal status. A. lwoffii was detected in blood cultures collected at the previous hospital, and susceptibility to piperacillin and meropenem to A. lwoffii was confirmed. The pneumonia responded to antibiotic treatment and there were no findings of infection in the neonate. Maternal sepsis is an infrequent but important complication, causing significant maternal and fetal morbidity and fetal and neonatal mortality; therefore, early antibiotic therapy is required to improve the clinical outcome.
Topics: Infant, Newborn; Humans; Pregnancy; Female; Middle Aged; Shock, Septic; Acinetobacter Infections; Cesarean Section; Anti-Bacterial Agents; Piperacillin; Pneumonia
PubMed: 37766560
DOI: 10.5387/fms.2022-43 -
Frontiers in Immunology 2023is a widespread Gram-negative pathogen involved in a variety of gastrointestinal diseases, including gastritis, ulceration, mucosa-associated lymphoid tissue (MALT)...
is a widespread Gram-negative pathogen involved in a variety of gastrointestinal diseases, including gastritis, ulceration, mucosa-associated lymphoid tissue (MALT) lymphoma and gastric cancer. Immune responses aimed at eradication of often prove futile, and paradoxically play a crucial role in the degeneration of epithelial integrity and disease progression. We have previously shown that infection of primary human monocytes increases their potential to respond to subsequent bacterial stimuli - a process that may be involved in the generation of exaggerated, yet ineffective immune responses directed against the pathogen. In this study, we show that -induced monocyte priming is not a common feature of Gram-negative bacteria, as induces tolerance to subsequent lipopolysaccharide (LPS) challenge. Although the increased reactivity of infected monocytes seems to be specific to , it appears to be independent of its virulence factors Cag pathogenicity island (CagPAI), cytotoxin associated gene A (CagA), vacuolating toxin A (VacA) and γ-glutamyl transferase (γ-GT). Utilizing whole-cell proteomics complemented with biochemical signaling studies, we show that infection of monocytes induces a unique proteomic signature compared to other pro-inflammatory priming stimuli, namely LPS and the pathobiont . Contrary to these tolerance-inducing stimuli, priming leads to accumulation of NF-кB proteins, including p65/RelA, and thus to the acquisition of a monocyte phenotype more responsive to subsequent LPS challenge. The plasticity of pro-inflammatory responses based on abundance and availability of intracellular signaling molecules may be a heretofore underappreciated form of regulating innate immune memory as well as a novel facet of the pathobiology induced by .
Topics: Humans; NF-kappa B; Bacterial Proteins; Helicobacter pylori; Trained Immunity; Lipopolysaccharides; Proteomics
PubMed: 38053995
DOI: 10.3389/fimmu.2023.1290833 -
BMC Veterinary Research May 2024Acinetobacter lwoffii (A.lwoffii) is a serious zoonotic pathogen that has been identified as a cause of infections such as meningitis, bacteremia and pneumonia. In...
BACKGROUND
Acinetobacter lwoffii (A.lwoffii) is a serious zoonotic pathogen that has been identified as a cause of infections such as meningitis, bacteremia and pneumonia. In recent years, the infection rate and detection rate of A.lwoffii is increasing, especially in the breeding industry. Due to the presence of biofilms, it is difficult to eradicate and has become a potential super drug-resistant bacteria. Therefore, eradication of preformed biofilm is an alternative therapeutic action to control A.lwoffii infection. The present study aimed to clarify that baicalin could eradicate A.lwoffii biofilm in dairy cows, and to explore the mechanism of baicalin eradicating A.lwoffii.
RESULTS
The results showed that compared to the control group, the 4 MIC of baicalin significantly eradicated the preformed biofilm, and the effect was stable at this concentration, the number of viable bacteria in the biofilm was decreased by 0.67 LogCFU/mL. The total fluorescence intensity of biofilm bacteria decreased significantly, with a reduction rate of 67.0%. There were 833 differentially expressed genes (367 up-regulated and 466 down-regulated), whose functions mainly focused on oxidative phosphorylation, biofilm regulation system and trehalose synthesis. Molecular docking analysis predicted 11 groups of target proteins that were well combined with baicalin, and the content of trehalose decreased significantly after the biofilm of A.lwoffii was treated with baicalin.
CONCLUSIONS
The present study evaluated the antibiofilm potential of baicalin against A.lwoffii. Baicalin revealed strong antibiofilm potential against A.lwoffii. Baicalin induced biofilm eradication may be related to oxidative phosphorylation and TCSs. Moreover, the decrease of trehalose content may be related to biofilm eradication.
Topics: Biofilms; Animals; Flavonoids; Acinetobacter; Cattle; Milk; Anti-Bacterial Agents; Microbial Sensitivity Tests; Molecular Docking Simulation; Female; Acinetobacter Infections
PubMed: 38764041
DOI: 10.1186/s12917-024-04015-w -
Applied Microbiology and Biotechnology Aug 2023While the in situ return of corn straw can improve soil fertility and farmland ecology, additional bacterial agents are required in low-temperature areas of northern...
While the in situ return of corn straw can improve soil fertility and farmland ecology, additional bacterial agents are required in low-temperature areas of northern China to accelerate straw degradation. Moisture is an important factor affecting microbial activity; however, owing to a lack of bacterial agents adapted to low-temperature complex soil environments, the effects of soil moisture on the interaction between exogenous bacterial agents and indigenous soil microorganisms remain unclear. To this end, we explored the effect of the compound bacterial agent CFF constructed using Pseudomonas putida and Acinetobacter lwoffii, developed to degrade corn straw in low-temperature soils (15 °C), on indigenous bacterial and fungal communities under dry (10% moisture content), slightly wet (20%), and wet (30%) soil-moisture conditions. The results showed that CFF application significantly affected the α-diversity of bacterial communities and changed both bacterial and fungal community structures, enhancing the correlation between microbial communities and soil-moisture content. CFF application also changed the network structure and the species of key microbial taxa, promoting more linkages among microbial genera. Notably, with an increase in soil moisture, CFF enhanced the rate of corn straw degradation by inducing positive interactions between bacterial and fungal genera and enriching straw degradation-related microbial taxa. Overall, our study demonstrates the alteration of indigenous microbial communities using bacterial agents (CFF) to overcome the limitations of indigenous microorganisms for in situ straw-return agriculture in low-temperature areas. KEY POINTS: • Low-temperature and variable moisture conditions (10-30%) were compared • Soil microbial network structure and linkages between genera were altered • CFF improves straw degradation via positive interactions between soil microbes.
Topics: Zea mays; Temperature; Soil Microbiology; Agriculture; Soil; Bacteria
PubMed: 37392246
DOI: 10.1007/s00253-023-12644-8 -
Antimicrobial Stewardship & Healthcare... 2023To describe antimicrobial therapy used for multidrug-resistant (MDR) bacteremia in Veterans and impacts on mortality.
OBJECTIVE
To describe antimicrobial therapy used for multidrug-resistant (MDR) bacteremia in Veterans and impacts on mortality.
METHODS
This was a retrospective cohort study of hospitalized Veterans Affairs patients from 2012 to 2018 with a positive MDR blood culture who received antimicrobial treatment 2 days prior to through 5 days after the culture date. Only the first culture per patient was used. The association between treatment and patient characteristics was assessed using bivariate analyses. Multivariable logistic regression models examined the relationship between antibiotic regimen and in-hospital, 30-day, and 1-year mortality. Generalized linear models were used to assess cost outcomes.
RESULTS
MDR was identified in 184 patients. Most cultures identified were , 3% were and 7% were other Penicillins-β-lactamase inhibitor combinations (51.1%) and carbapenems (51.6%)-were the most prescribed antibiotics. In unadjusted analysis, extended spectrum cephalosporins and penicillins-β-lactamase inhibitor combinations-were associated with a decreased odds of 30-day mortality but were insignificant after adjustment (adjusted odds ratio (aOR) = 0.47, 95% CI, 0.21-1.05, aOR = 0.75, 95% CI, 0.37-1.53). There was no association between combination therapy vs monotherapy and 30-day mortality (aOR = 1.55, 95% CI, 0.72-3.32).
CONCLUSION
In hospitalized Veterans with MDR ., none of the treatments were shown to be associated with in-hospital, 30-day, and 1-year mortality. Combination therapy was not associated with decreased mortality for MDR bacteremia.
PubMed: 38156232
DOI: 10.1017/ash.2023.500 -
Cutaneous and Ocular Toxicology Mar 2024This study aimed to investigate the effects of commercial tattoo inks used in corneal tattooing on conjunctival microbiota.
PURPOSE
This study aimed to investigate the effects of commercial tattoo inks used in corneal tattooing on conjunctival microbiota.
METHOD
This prospective case control study consisted of 125 participants divided in the following three groups: 35 patients with corneal tattoos, 40 patients with corneal leukoma, and 50 healthy subjects. Corneal tattooing was performed in all the cases in this study using a tattoo pen machine and commercial tattoo ink. A total of 500 cultures were taken from 250 eyes of 125 individuals on chocolate and sheep blood agar. Bacteriological samples were taken from the inferior eyelid conjunctiva using a sterile cotton swab. Without any contact elsewhere, the swabs were smeared on bedside chocolate agars and 5% sheep blood agar.
RESULTS
In tattooed eyes, bacterial growth was detected in 42.9% of the chocolate and sheep blood agar samples. In other healthy eyes of patients with corneal tattoos, 54.5% bacterial growth on chocolate agar and 57.1% on sheep blood agar were detected. No statistical difference was detected in the conjunctival microbiota of chocolate and sheep blood agar ( = 0.254, = 0.134, respectively) in the tattooed eyes compared to the other eye of the individual. No statistically significant difference was found in terms of bacterial growth in tattooed, leukoma, or healthy eyes on chocolate and sheep blood agar ( = 0.408, = 0.349). The growth rate of decreased by 33.3% (from 12 to 8) on chocolate agar in 35 tattooed eyes, and it decreased by 28.5% (from 14 to 10) on sheep blood agar, while gram-negative bacteria , , and were detected in three patients.
CONCLUSION
Corneal tattooing using commercial dye does not affect conjunctival microbiota. In the past 3 years, 120 patients have been tattooed with commercial tattoo ink in Istanbul Medeniyet University Göztepe Training and Research Hospital. No complications related to infection were found in the 3-year follow-up. The gram-negative bacteria detected in the healthy control group and tattooed eyes were bacteria found on normal skin or in the respiratory tract. Although some gram-negative bacteria do not cause infection, careful eye examination, follow-up, and culture are required in suspicious cases.
Topics: Animals; Sheep; Humans; Tattooing; Agar; Case-Control Studies; Conjunctiva; Corneal Opacity
PubMed: 37879108
DOI: 10.1080/15569527.2023.2275025 -
BMC Veterinary Research Jun 2024Acinetobacter 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...
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.
Topics: Animals; Cattle; Mastitis, Bovine; Female; Acinetobacter; Milk; China; Anti-Bacterial Agents; Microbial Sensitivity Tests; Acinetobacter Infections; Drug Resistance, Bacterial; Drug Resistance, Multiple, Bacterial
PubMed: 38918815
DOI: 10.1186/s12917-024-04119-3 -
MSphere May 2024The two species that account for most cases of -associated bacteremia in the United Kingdom are , often a commensal but also an emerging pathogen, and , a well-known...
UNLABELLED
The two species that account for most cases of -associated bacteremia in the United Kingdom are , often a commensal but also an emerging pathogen, and , a well-known antibiotic-resistant species. While these species both cause similar types of human infection and occupy the same niche, (unlike ) has thus far remained susceptible to antibiotics. Comparatively little is known about the biology of , and this is the largest study on it conducted to date, providing valuable insights into its behaviour and potential threat to human health. This study aimed to explain the antibiotic susceptibility, virulence, and fundamental biological differences between these two species. The relative susceptibility of was explained as it encoded fewer antibiotic resistance and efflux pump genes than (9 and 30, respectively). While both species had markers of horizontal gene transfer, encoded more DNA defense systems and harbored a far more restricted range of plasmids. Furthermore, displayed a reduced ability to select for antibiotic resistance mutations, form biofilm, and infect both and in models of infection. This study suggests that the emerging pathogen has remained susceptible to antibiotics because mechanisms exist to make it highly selective about the DNA it acquires, and we hypothesize that the fact that it only harbors a single RND system restricts the ability to select for resistance mutations. This provides valuable insights into how development of resistance can be constrained in Gram-negative bacteria.
IMPORTANCE
is often a harmless commensal but is also an emerging pathogen and is the most common cause of -derived bloodstream infections in England and Wales. In contrast to the well-studied and often highly drug-resistant , has remained susceptible to antibiotics. This study explains why this organism has not evolved resistance to antibiotics. These new insights are important to understand why and how some species develop antibiotic resistance, while others do not, and could inform future novel treatment strategies.
Topics: Acinetobacter; Virulence; Acinetobacter Infections; Anti-Bacterial Agents; Biofilms; Microbial Sensitivity Tests; Animals; Humans; Drug Resistance, Bacterial; Acinetobacter baumannii; Mice; Gene Transfer, Horizontal; United Kingdom; Female; Plasmids
PubMed: 38578105
DOI: 10.1128/msphere.00109-24