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Bioresource Technology Jul 2024Immobilization technology is a promising way to improve effectiveness and stability of microbial remediation for polycyclic aromatic hydrocarbons (PAHs), in which...
Immobilization technology is a promising way to improve effectiveness and stability of microbial remediation for polycyclic aromatic hydrocarbons (PAHs), in which carrier material is one of key factors restricting removal efficiency. In this study, fulvic acid-wheat straw biochar (FA/WS) composites were applied for immobilization of an efficient PAHs degrading bacterium Stenotrophomonas maltophilia (SPM). FA/WS&SPM showed superior degradation capacity than free bacteria and biochar-immobilized bacteria, with the removal efficiency of pyrene (20 mg L) reaching 90.5 % (7 days). Transcriptome analysis revealed that FA in the carrier materials can promote transportation and degradation of pyrene, and cell growth, as well as inhibit cell apoptosis. Enzyme activity and degradation products detection showed that SPM utilized both phthalic acid and salicylic acid metabolic pathways to degrade pyrene. Practicality of FA/WS&SPM for different kinds of PAHs remediation had been verified in contaminated soil, demonstrating a great potential in the field of PAHs polluted sites remediation.
Topics: Stenotrophomonas maltophilia; Pyrenes; Biodegradation, Environmental; Benzopyrans; Cells, Immobilized; Charcoal
PubMed: 38763203
DOI: 10.1016/j.biortech.2024.130857 -
Experimental Parasitology Jul 2024Acanthamoeba spp., are common free-living amoebae found in nature that can serve as reservoirs for certain microorganisms. The SARS-CoV-2 virus is a newly emerged...
Acanthamoeba spp., are common free-living amoebae found in nature that can serve as reservoirs for certain microorganisms. The SARS-CoV-2 virus is a newly emerged respiratory infection, and the investigation of parasitic infections remains an area of limited research. Given that Acanthamoeba can act as a host for various endosymbiotic microbial pathogens and its pathogenicity assay is not fully understood, this study aimed to identify Acanthamoeba and its bacterial and fungal endosymbionts in patients with chronic respiratory disorders and hospitalized COVID-19 patients in northern Iran. Additionally, a pathogenicity assay was conducted on Acanthamoeba isolates. Urine, nasopharyngeal swab, and respiratory specimens were collected from two groups, and each sample was cultured on 1.5% non-nutrient agar medium. The cultures were then incubated at room temperature and monitored daily for a period of two weeks. Eight Acanthamoeba isolates were identified, and PCR was performed to confirm the presence of amoebae and identify their endosymbionts. Four isolates were found to have bacterial endosymbionts, including Stenotrophomonas maltophilia and Achromobacter sp., while two isolates harbored fungal endosymbionts, including an uncultured fungus and Gloeotinia sp. In the pathogenicity assay, five isolates exhibited a higher degree of pathogenicity compared to the other three. This study provides significant insights into the comorbidity of acanthamoebiasis and COVID-19 on a global scale, and presents the first evidence of Gloeotinia sp. as a fungal endosymbiont. Nevertheless, further research is required to fully comprehend the symbiotic patterns and establish effective treatment protocols.
Topics: Humans; Iran; Acanthamoeba; COVID-19; Symbiosis; SARS-CoV-2; Male; Female; Stenotrophomonas maltophilia; Middle Aged; Adult; Amebiasis; Polymerase Chain Reaction; Aged; Vero Cells; Hospitalization; Chlorocebus aethiops
PubMed: 38754618
DOI: 10.1016/j.exppara.2024.108774 -
Indian Journal of Medical Microbiology 2024The objective of this investigation was to examine the mechanisms associated with antibiotic resistance in Stenotrophomonas maltophilia clinical isolates retrieved from...
OBJECTIVES
The objective of this investigation was to examine the mechanisms associated with antibiotic resistance in Stenotrophomonas maltophilia clinical isolates retrieved from hospitalized patients undergoing open heart surgery in a Heart Center located in Tehran, Iran.
MATERIALS AND METHODS
This investigation encompassed a cross-sectional study of 60 S. maltophilia isolates, which were procured from diverse clinical specimens. Primary identification of the isolates was conducted through conventional microbiologic methods and subsequently verified by means of PCR primers. The E-test was utilized to establish the minimum inhibitory concentrations (MICs). PCR was then employed to ascertain the antibiotic resistance genes (sul1, sul2, Smqnr and intl1 - intl3).
RESULTS
In this study, a total of sixty clinical isolates of S. maltophilia were collected, with the majority of them being obtained from Intensive Care Units (ICU) (n = 54; 90%). The disk diffusion method yielded results indicating that 55% of the isolates were sensitive to minocycline, whereas 30% were intermediate and 15% were found to be resistant. Additionally, the MIC results revealed that the resistant rates of the isolates towards ceftazidime, cotrimoxazole and levofloxacin were 46.7%, 1.7% and 5%, respectively. The PCR amplification of three classes of integrons genes indicated that fifteen (25%) of the isolates carried int1, while no detection for intl2 and intl3 was reported. Furthermore, the prevalence of antibiotic resistance genes (sul1, sul2, and Smqnr) was identified in 15 (25%), 6 (10%), and 28 (46.7%) isolates, respectively.
CONCLUSION
The reported increasing rate of antibiotic resistance and mobile genetic elements that could extend the resistance genes to other strains in the hospital, finally it could be an alarming issue for healthcare settings that need special attention to this strain and the epidemiological study on this issue.
Topics: Humans; Stenotrophomonas maltophilia; Integrons; Microbial Sensitivity Tests; Iran; Cross-Sectional Studies; Gram-Negative Bacterial Infections; Anti-Bacterial Agents; Drug Resistance, Bacterial; Polymerase Chain Reaction; Prevalence; Genes, Bacterial; Bacterial Proteins; Male
PubMed: 38750966
DOI: 10.1016/j.ijmmb.2024.100612 -
The Science of the Total Environment Jul 2024The presence of Stenotrophomonas maltophilia in aquatic environments poses great health risks to immunocompromised individuals because of its multidrug resistance and...
The presence of Stenotrophomonas maltophilia in aquatic environments poses great health risks to immunocompromised individuals because of its multidrug resistance and resultant high mortality. However, a significant gap exists in the isolation and understanding of colistin-resistant S. maltophilia in aquatic environments. In this study, nine colistin-resistant S. maltophilia strains isolated from natural lakes were explored, and their phylogenetic relationship, biofilm formation, virulence, and antibiotic resistance profiles and underlying genetic determinants were assessed. After genome analysis, besides known multi-locus sequence typing (MLST) of ST532, new assigned ST965 and ST966 which phylogenetically clustered into soil isolates were found firstly. All the isolates exhibited resistance to multiple antibiotics, including aminoglycosides, beta-lactams, tetracyclines, and even colistin, with the highest minimum inhibitory concentration (MIC) against colistin reaching 640 mg/L. Comparative genomic analysis revealed aph(3')-Iic, bla, tetT, phoP, mcr-3, arnA, pmrE, and efflux pump genes as the genetic determinants underlying this multidrug resistance. Notably, the biofilm-forming capacities of the newly discovered ST965 and ST966 isolates were significant stronger than those of the known ST532 isolates (p < 0.01), resulting in the death of over 50 % of the Galleria mellonella population within 1 day of injection. The ST965 isolates demonstrated the highest virulence against G. mellonella, followed by the ST966 isolates and ST532 isolates which was phylogenetically clustered with clinical isolates, indicating that the novel S. maltophilia strains of ST965 and ST966 may pose considerable health risks to humans. Our findings provide insights into colistin-resistant S. maltophilia in aquatic environments and raise concerns about the health risks posed by the newly assigned sequence types of colistin-resistant S. maltophilia with potential high virulence in natural aquatic environments.
Topics: Stenotrophomonas maltophilia; Colistin; Anti-Bacterial Agents; Virulence; Microbial Sensitivity Tests; Phylogeny; Biofilms; Lakes; Animals; Drug Resistance, Multiple, Bacterial; Drug Resistance, Bacterial
PubMed: 38750746
DOI: 10.1016/j.scitotenv.2024.173221 -
Microbiology Spectrum Jun 2024Malignant central airway stenosis is treated with airway stent placement, but post-placement microbial characteristics remain unclear. We studied microbial features in...
UNLABELLED
Malignant central airway stenosis is treated with airway stent placement, but post-placement microbial characteristics remain unclear. We studied microbial features in 60 patients post-stent placement, focusing on changes during granulation tissue proliferation. Samples were collected before stent ( = 29), after stent on day 3 ( = 20), and after granulation tissue formation (AS-GTF, = 43). Metagenomic sequencing showed significant respiratory tract microbiota changes with granulation tissue. The microbiota composition, dominated by , , and , was similar among the groups. At the species level, the AS-GTF group exhibited significant differences, with and enriched. Analysis based on tracheoesophageal fistula presence identified and as the main differential species, enriched in the fistula subgroup. Viral and fungal detection showed and as the main species, respectively. These findings highlight microbiota changes after stent placement, potentially associated with granulation tissue proliferation, informing stent placement therapy and anti-infective treatment optimization.
IMPORTANCE
Malignant central airway stenosis is a life-threatening condition that can be effectively treated with airway stent placement. However, despite its clinical importance, the microbial characteristics of the respiratory tract following stent insertion remain poorly understood. This study addresses this gap by investigating the microbial features in patients with malignant central airway stenosis after stent placement, with a specific focus on microbial changes during granulation tissue proliferation. The findings reveal significant alterations in the diversity and structure of the respiratory tract microbiota following the placement of malignant central airway stents. Notably, certain bacterial species, including and , exhibit distinct patterns in the after-stent granulation tissue formation group. Additionally, the presence of tracheoesophageal fistula further influences the microbial composition. These insights provide valuable references for optimizing stent placement therapy and enhancing clinical anti-infective strategies.
Topics: Humans; Stents; Female; Male; Microbiota; Middle Aged; Aged; Bacteria; Airway Obstruction; Respiratory System; Granulation Tissue; Adult; Aged, 80 and over; Tracheoesophageal Fistula
PubMed: 38747599
DOI: 10.1128/spectrum.03472-23 -
Current Microbiology May 2024India's livestock industry is grappling with a shortage of green fodder, necessitating concerted efforts to boost organized production and ensure a sufficient supply of...
India's livestock industry is grappling with a shortage of green fodder, necessitating concerted efforts to boost organized production and ensure a sufficient supply of high-quality forages, crucial for formulating nutritionally balanced, cost-effective, and rumen-healthy animal diets. Hence, this study was conducted to assess the plant growth-promoting characteristics of liquid microbial inoculants and their impact on the yield of forage pearl millet. The bacterial cultures utilized included Sphingobacterium sp., Stenotrophomonas maltophilia, and an isolate from vegetable cowpea, subsequently identified as Burkholderia seminalis. These cultures were initially characterized for their plant growth-promoting traits at different temperature and physiological conditions. All the bacterial cultures were found promising for PGPR traits over varied temperature conditions and the optimum activity was recorded at 40 °C, with tolerance to saline and drought stresses as well as wide pH and temperature ranges. A field experiment was conducted during kharif 2020 at Punjab Agricultural University, Ludhiana and Punjab Agricultural University, Regional Research Station, Bathinda, involving combinations of liquid microbial inoculants along with 100% Recommended Dose of Fertilizer (RDF). It was observed that the treatment including B. seminalis + S. maltophilia along with RDF yielded the highest green fodder and dry matter yield, In conclusion, it is evident that the utilization of these liquid microbial inoculants holds significant potential for playing a pivotal role in the integrated nutrient management of forage pearl millet, thereby contributing to heightened productivity and sustained soil health.
Topics: Pennisetum; Animal Feed; Animals; India; Soil Microbiology; Temperature; Fertilizers; Plant Development; Bacteria
PubMed: 38744734
DOI: 10.1007/s00284-024-03701-0 -
Frontiers in Microbiology 2024is an opportunistic pathogen intrinsically resistant to multiple and broad-spectrum antibiotics. Although the bacterium is considered a low-virulence pathogen, it can... (Review)
Review
is an opportunistic pathogen intrinsically resistant to multiple and broad-spectrum antibiotics. Although the bacterium is considered a low-virulence pathogen, it can cause various severe diseases and contributes significantly to the pathogenesis of multibacterial infections. During the COVID-19 pandemic, has been recognized as one of the most common causative agents of respiratory co-infections and bacteremia in critically ill COVID-19 patients. The high ability to adapt to unfavorable environments and new habitat niches, as well as the sophisticated switching of metabolic pathways, are unique mechanisms that attract the attention of clinical researchers and experts studying the fundamental basis of virulence. In this review, we have summarized the current knowledge on the molecular aspects of virulence and putative virulence factors, partially touched on interspecific bacterial interactions and iron uptake systems in the context of virulence, and have not addressed antibiotic resistance.
PubMed: 38741741
DOI: 10.3389/fmicb.2024.1385631 -
Expert Review of Anti-infective Therapy May 2024The aim of this study was to compare the safety and effectiveness of monotherapy versus combination therapy for the treatment of infections caused by .
BACKGROUND
The aim of this study was to compare the safety and effectiveness of monotherapy versus combination therapy for the treatment of infections caused by .
METHODS
This retrospective, multicenter, cohort study included patients treated with either monotherapy or combination therapy for infections caused by . Primary outcomes included overall in-hospital mortality, 30-day mortality, and clinical cure. Safety outcomes were also evaluated. Multivariable logistic regression was used as a control for confounding variables.
RESULTS
A total of 407 patients were included, 330 patients received monotherapy and 77 patients received combination therapy. A total of 21% presented with concomitant bacteremia. After adjusting the differences between the two groups, there were no statistically significant differences between patients who received monotherapy versus combination therapy in clinical cure (55% vs 65%; OR, 0.72; 95% CI, 0.40-1.31) and overall in-hospital mortality (52% vs 49%; OR, 0.84; 95% CI, 0.45-1.57). However, patients who received monotherapy had a lower rate of 30-day mortality (28% vs 32%; OR, 0.45; 95% CI, 0.22-0.90) and acute kidney injury (9% vs 18%; OR, 0.35; 95% CI, 0.16-0.78).
CONCLUSION
Clinical outcomes did not significantly differ in patients who received combination therapy versus monotherapy. More data are needed to validate these findings.
PubMed: 38738566
DOI: 10.1080/14787210.2024.2353704 -
Annals of Intensive Care May 2024The efficacy and safety of cefiderocol in ICU patients with difficult-to-treat resistance (DTR) non-fermenting Gram-negative bacteria (Nf-GNB) are not as...
BACKGROUND
The efficacy and safety of cefiderocol in ICU patients with difficult-to-treat resistance (DTR) non-fermenting Gram-negative bacteria (Nf-GNB) are not as well-established. Consequently, we conducted a cohort study to compare Cefiderocol with the Best Available Therapy (BAT) in ICU patients.
METHODS
We included adult patients from 9 different ICUs, including a burn ICU unit, from 2019 to 2023 treated with Cefiderocol for DTR Nf-GNB isolated from the blood or lungs. We matched each patient at a 1:2 ratio based on the same DTR Nf-GBN isolated pathogen, and when possible, within the same type of ICU (burn unit or not). The primary endpoint of the study was the clinical cure at 15 days, with secondary endpoints including clinical cure at 30 days, relapse, and in-ICU mortality. For each outcome, adjusted odds ratios were estimated using bidirectional stepwise regression in a final model, which included 13 preselected confounders.
RESULTS
We included 27 patients with cefiderocol, matched with 54 patients receiving the BAT. Four patients were not exactly matched on the type of ICU unit. Characteristics were comparable between groups, mostly male with a Charlson Comorbidity Index of 3 [1-5], and 28% had immunosuppression. Cefiderocol patients were most likely to have higher number of antibiotic lines. The main DTR Nf-GNB identified was Pseudomonas aeruginosa (81.5%), followed by Acinetobater baumanii (14.8%) and Stenotrophomonas maltophilia (3.7%). Pneumonia was the identified infection in 21 (78.8%) patients in the Cefiderocol group and in 51 (94.4%) patients in the BAT group (p = 0.054). Clinical cure at 15 and 30-day and the in-ICU mortality was comparable between groups, however relapse was higher in the cefiderocol group (8-29.6% vs. 4-7.4%;aOR 10.06[1.96;51.53]) CONCLUSION: Cefiderocol did not show an improvement in clinical cure or mortality rates compared to BAT in the treatment of DTR Nf-GNB, but it was associated with a higher relapse rate.
PubMed: 38736016
DOI: 10.1186/s13613-024-01308-z -
Food Research International (Ottawa,... Jun 2024Exploring the contribution of common microorganisms to spoilage is of great significance in inhibiting spoilage in lamb. This work investigated the extent of protein...
Exploring the contribution of common microorganisms to spoilage is of great significance in inhibiting spoilage in lamb. This work investigated the extent of protein degradation and profile changes of free amino acids (FAAs), free fatty acids (FFAs) and volatile organic compounds (VOCs) in lamb caused by single- and co-culture of the common aerobic spoilage bacteria, P. paralactis, Ac. MN21 and S. maltophilia. Meanwhile, some key VOCs produced by the three bacteria during lamb spoilage were also screened by orthogonal partial least square discriminant analysis and difference value in VOCs content between inoculated groups and sterile group. Lamb inoculated with P. paralactis had the higher total viable counts, pH, total volatile base nitrogen and TCA-soluble peptides than those with the other two bacteria. Some FAAs and FFAs could be uniquely degraded by P. paralactis but not Ac. MN21 and S. maltophilia, such as Arg, Glu, C15:0, C18:0 and C18:1n9t. Co-culture of the three bacteria significantly promoted the overall spoilage, including bacterial growth, proteolysis and lipolysis. Key VOCs produced by P. paralactis were 2, 3-octanedione, those by Ac. MN21 were 1-octanol, octanal, hexanoic acid, 1-pentanol and hexanoic acid methyl ester, and that by S. maltophilia were hexanoic acid. The production of extensive key-VOCs was significantly and negatively correlated with C20:0, C23:0 and C18:ln9t degradation. This study can provide a basis for inhibiting common spoilage bacteria and promoting high-quality processing of fresh lamb.
Topics: Animals; Coculture Techniques; Volatile Organic Compounds; Pseudomonas; Acinetobacter; Stenotrophomonas maltophilia; Food Microbiology; Red Meat; Sheep; Food Storage; Cold Temperature; Fatty Acids, Nonesterified; Amino Acids; Sheep, Domestic; Proteolysis
PubMed: 38729689
DOI: 10.1016/j.foodres.2024.114313