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Antimicrobial Resistance and Infection... Jun 2024Stenotrophomonas maltophilia, a multidrug-resistant gram-negative bacteria (GNB), is an emerging nosocomial pathogen. This study assessed the clinical outcomes of GNB...
Gram-negative bacterial infections in surgical intensive care unit patients following abdominal surgery: high mortality associated with Stenotrophomonas maltophilia infection.
BACKGROUND
Stenotrophomonas maltophilia, a multidrug-resistant gram-negative bacteria (GNB), is an emerging nosocomial pathogen. This study assessed the clinical outcomes of GNB infections in surgical intensive care unit (SICU) patients post-abdominal surgery, focusing on the differences between S. maltophilia and other GNBs, including Pseudomonas aeruginosa.
METHODS
A retrospective study was conducted on SICU patients at Kaohsiung Chang Gung Memorial Hospital from 2010 to 2020, who developed GNB infections following abdominal surgery.
RESULTS
Of 442 patients, 237 had S. maltophilia and 205 had non-S. maltophilia GNB infections (including 81 with P. aeruginosa). The overall mortality rate was 44.5%, and S. maltophilia infection emerged as a significant contributor to the mortality rate in patients with GNB infections. S. maltophilia patients had longer mechanical ventilation and SICU stays, with a 30-day mortality rate of 35.4%, higher than the non-S. maltophilia GNB (22.9%) and P. aeruginosa (21%) groups. In-hospital mortality was also higher in the S. maltophilia group (53.2%) compared to the non-S. maltophilia GNB (34.6%) and P. aeruginosa groups (29.6%). Risk factors for acquiring S. maltophilia included a higher Sequential Organ Failure Assessment score and prior broad-spectrum antibiotics use. Older age, polymicrobial infections, and elevated bilirubin were associated with increased 30-day mortality in S. maltophilia patients.
CONCLUSION
S. maltophilia infections in post-abdominal surgery patients are linked to higher mortality than non-S. maltophilia GNB and P. aeruginosa infections, emphasizing the need for early diagnosis and treatment to improve outcomes.
Topics: Humans; Stenotrophomonas maltophilia; Gram-Negative Bacterial Infections; Male; Retrospective Studies; Female; Middle Aged; Intensive Care Units; Aged; Abdomen; Hospital Mortality; Pseudomonas aeruginosa; Adult; Cross Infection; Anti-Bacterial Agents
PubMed: 38886759
DOI: 10.1186/s13756-024-01411-7 -
BMC Infectious Diseases Jun 2024Urinary tract infection is one of the most common infections in humans, affecting women in more proportion. The bladder was considered sterile, but it has a urinary...
BACKGROUND
Urinary tract infection is one of the most common infections in humans, affecting women in more proportion. The bladder was considered sterile, but it has a urinary microbiome. Moreover, intracellular bacteria (IB) were observed in uroepithelial cells from children and women with urinary tract infections (UTIs). Here, we evaluated the presence of IB in urine from healthy people and patients with UTI symptoms.
METHODS
Midstream urine was self-collected from 141 donors, 77 females and 64 males; 72 belonged to the asymptomatic group and 69 were symptomatic. IB was characterized by a culture-dependent technique and visualized by confocal microscopy. Urine was also subjected to the classical uroculture and isolated bacteria were identified by MALDI-TOF.
RESULTS
One-hundred and fifteen uroculture were positive. A significant association was observed between the presence of symptoms and IB (P = 0.007). Moreover, a significant association between the presence of IB, symptoms and being female was observed (P = 0.03). From the cases with IB, Escherichia coli was the most frequent microorganism identified (34.7%), followed by Stenotrophomonas maltophilia (14.2%), Staphylococcus spp (14.2%), and Enterococcus faecalis (10.7%). Intracellular E. coli was associated with the symptomatic group (P = 0.02). Most of the intracellular Staphylococcus spp. were recovered from the asymptomatic group (P = 0.006).
CONCLUSIONS
Intracellular bacteria are present in patients with UTI but also in asymptomatic people. Here, we report for the first time, the presence of S. maltophilia, Staphylococcus spp., and Enterobacter cloacae as intracellular bacteria in uroepithelial cells. These findings open new insights into the comprehension of urinary tract infections, urinary microbiome and future therapies. Uroculture as the gold standard could not be enough for an accurate diagnosis in recurrent or complicated cases.
Topics: Humans; Female; Male; Urinary Tract Infections; Adult; Middle Aged; Bacteria; Urothelium; Epithelial Cells; Urine; Young Adult; Aged; Microbiota; Adolescent
PubMed: 38886658
DOI: 10.1186/s12879-024-09489-5 -
GMS Hygiene and Infection Control 2024The aims of this study were to: (i) determine antibiotic susceptibility of clinical isolates, (ii) investigate the presence of different classes of integrons and genes...
AIM
The aims of this study were to: (i) determine antibiotic susceptibility of clinical isolates, (ii) investigate the presence of different classes of integrons and genes responsible for sulphonamide resistance, (iii) assess the molecular epidemiology of the isolates by determining their clonal relatedness, and (iv) investigate the potential sources of infection by collecting environmental samples when necessary.
METHODS
99 isolates from clinical specimens of hospitalized patients were screened by PCR for , , genes, and integron-associated integrase genes: , , and . PFGE was used to determine the clonal relatedness of the isolates.
RESULTS
Susceptibility rates for trimethoprim-sulfamethoxazole, levofloxacin, and ceftazidime were 90.9%, 91.9%, and 53.5% respectively. All trimethoprim-sulfamethoxazole-resistant isolates were positive for and . PFGE analysis revealed that 24 of the isolates were clonally related, clustering in seven different clones. Five of the nine trimethoprim-sulfamethoxazole-resistant isolates were clonally related. The first isolate in this clone was from a wound sample of a patient in the infectious diseases clinic, and the other four were isolated from the bronchoalveolar lavage samples of patients in the thoracic surgery unit. The patient with the first isolate neither underwent bronchoscopy nor stayed in the thoracic surgery unit. Although clustering was observed in bronchoalveolar lavage samples, no growth was detected in environmental samples.
CONCLUSION
The findings demonstrated that the gene carried by class 1 integrons plays an important role in trimethoprim-sulfamethoxazole resistance in isolates. PFGE analysis revealed a high degree of genetic diversity. However, detection of clonally related isolates suggests the acquisition from a common source and/or cross-transmission of this microorganism between the patients.
PubMed: 38883406
DOI: 10.3205/dgkh000481 -
PloS One 2024Evaluate the effects of five disinfection methods on bacterial concentrations in hospital sink drains, focusing on three opportunistic pathogens (OPs): Serratia...
OBJECTIVE
Evaluate the effects of five disinfection methods on bacterial concentrations in hospital sink drains, focusing on three opportunistic pathogens (OPs): Serratia marcescens, Pseudomonas aeruginosa and Stenotrophomonas maltophilia.
DESIGN
Over two years, three sampling campaigns were conducted in a neonatal intensive care unit (NICU). Samples from 19 sink drains were taken at three time points: before, during, and after disinfection. Bacterial concentration was measured using culture-based and flow cytometry methods. High-throughput short sequence typing was performed to identify the three OPs and assess S. marcescens persistence after disinfection at the genotypic level.
SETTING
This study was conducted in a pediatric hospitals NICU in Montréal, Canada, which is divided in an intensive and intermediate care side, with individual rooms equipped with a sink.
INTERVENTIONS
Five treatments were compared: self-disinfecting drains, chlorine disinfection, boiling water disinfection, hot tap water flushing, and steam disinfection.
RESULTS
This study highlights significant differences in the effectiveness of disinfection methods. Chlorine treatment proved ineffective in reducing bacterial concentration, including the three OPs. In contrast, all other drain interventions resulted in an immediate reduction in culturable bacteria (4-8 log) and intact cells (2-3 log). Thermal methods, particularly boiling water and steam treatments, exhibited superior effectiveness in reducing bacterial loads, including OPs. However, in drains with well-established bacterial biofilms, clonal strains of S. marcescens recolonized the drains after heat treatments.
CONCLUSIONS
Our study supports thermal disinfection (>80°C) for pathogen reduction in drains but highlights the need for additional trials and the implementation of specific measures to limit biofilm formation.
Topics: Serratia marcescens; Intensive Care Units, Neonatal; Disinfection; Humans; Pseudomonas aeruginosa; Infant, Newborn; Stenotrophomonas maltophilia; Serratia Infections; Cross Infection
PubMed: 38865328
DOI: 10.1371/journal.pone.0304378 -
Frontiers in Microbiology 2024, a wild plant in southern Africa, is utilized in traditional medicine for various ailments, leading to its endangerment and listing on the Red List of South African...
, a wild plant in southern Africa, is utilized in traditional medicine for various ailments, leading to its endangerment and listing on the Red List of South African Plants. To date, there have been no reports on bacterial endophytes from this plant, their classes of secondary metabolites, and potential medicinal properties. This study presents (i) taxonomic characterization of bacterial endophytes in leaf and root tissues using 16S rRNA, (ii) bacterial isolation, morphological, and phylogenetic characterization, (iii) bacterial growth, metabolite extraction, and LC-MS-based metabolite fingerprinting, and (iv) antimicrobial testing of bacterial crude extracts. Next-generation sequencing yielded 693 and 2,459 DNA read counts for the rhizomes and leaves, respectively, detecting phyla including Proteobacteria, Bacteroidota, Gemmatimonadota, Actinobacteriota, Verrucomicrobiota, Dependentiae, Firmicutes, and Armatimonodata. At the genus level, , , , and Ralstonia were the most dominant in both leaves and rhizomes. From root tissues, four bacterial isolates were selected, and 16S rRNA-based phylogenetic characterization identified two closely related sp. (strain BNWU4 and 5), BNWU2, and BNWU1. The ethyl acetate:chloroform (1:1 v/v) organic extract from each isolate exhibited antimicrobial activity against all selected bacterial pathogens. Strain BNWU5 displayed the highest activity, with minimum inhibitory concentrations ranging from 62.5 μg/mL to 250 μg/mL against diarrhoeagenic , , , antibiotic-resistant , , , and . LC-MS analysis of the crude extract revealed common antimicrobial metabolites produced by all isolates, including Phenoxomethylpenicilloyl (penicilloyl V), cis-11-Eicosenamide, 3-Hydroxy-3-phenacyloxindole, and 9-Octadecenamide.
PubMed: 38855763
DOI: 10.3389/fmicb.2024.1383854 -
Iranian Journal of Microbiology Apr 2024is an opportunistic pathogen causing nosocomial infections. Diclofenac is an anti-inflammatory drug that is considered a non-antibiotic drug. This study assessed the...
BACKGROUND AND OBJECTIVES
is an opportunistic pathogen causing nosocomial infections. Diclofenac is an anti-inflammatory drug that is considered a non-antibiotic drug. This study assessed the antibacterial and antibiofilm effects of diclofenac and levofloxacin/diclofenac combination against levofloxacin resistant isolates.
MATERIALS AND METHODS
Minimum inhibitory concentration was determined using broth microdilution method for levofloxacin, diclofenac, and levofloxacin/diclofenac combination. Biofilm forming capacity and biofilm inhibition assay were determined. Relative gene expression was measured for efflux pump genes; , and genes and biofilm related genes , and without and with diclofenac and the combination.
RESULTS
Diclofenac demonstrated MIC of 1 mg/ml. The combination-with ½ MIC diclofenac-showed synergism where levofloxacin MIC undergone 16-32 fold decrease. All the isolates that overexpressed and showed a significant decrease in gene expression in presence of diclofenac or the combination. The mean percentage inhibition of biofilm formation with diclofenac and the combination was 40.59% and 46.49%, respectively. This agreed with biofilm related genes expression investigations.
CONCLUSION
Diclofenac showed an antibacterial effect against The combination showed synergism, significant reduction in biofilm formation and in the relative level of gene expression. Furthermore, it can potentiate the levofloxacin activity or revert its resistance.
PubMed: 38854979
DOI: 10.18502/ijm.v16i2.15349 -
The Journal of Antimicrobial... Jun 2024Stenotrophomonas maltophilia is a carbapenem-resistant Gram-negative pathogen increasingly responsible for difficult-to-treat nosocomial infections.
BACKGROUND
Stenotrophomonas maltophilia is a carbapenem-resistant Gram-negative pathogen increasingly responsible for difficult-to-treat nosocomial infections.
OBJECTIVES
To describe the contemporary clinical characteristics and genome epidemiology of patients colonized or infected by S. maltophilia in a multicentre, prospective cohort.
METHODS
All patients with a clinical culture growing S. maltophilia were enrolled at six tertiary hospitals across Japan between April 2019 and March 2022. The clinical characteristics, outcomes, antimicrobial susceptibility and genomic epidemiology of cases with S. maltophilia were investigated.
RESULTS
In total, 78 patients were included representing 34 infection and 44 colonization cases. The median age was 72.5 years (IQR, 61-78), and males accounted for 53 cases (68%). The most common comorbidity was localized solid malignancy (39%). Nearly half of the patients (44%) were immunosuppressed, with antineoplastic chemotherapy accounting for 31%. The respiratory tract was the most common site of colonization (86%), whereas bacteraemia accounted for most infection cases (56%). The 30 day all-cause mortality rate was 21%, which was significantly higher in infection cases than colonization cases (35% versus 9%; adjusted HR, 3.81; 95% CI, 1.22-11.96). Susceptibility rates to ceftazidime, levofloxacin, minocycline and sulfamethoxazole/trimethoprim were 14%, 65%, 87% and 100%, respectively. The percentage of infection ranged from 13% in the unclassified group to 86% in genomic group 6A. The percentage of non-susceptibility to ceftazidime ranged from 33% in genomic group C to 100% in genomic groups 6 and 7 and genomic group geniculate.
CONCLUSIONS
In this contemporary multicentre cohort, S. maltophilia primarily colonized the respiratory tract, whereas patients with bacteraemia had the highest the mortality from this pathogen. Sulfamethoxazole/trimethoprim remained consistently active, but susceptibility to levofloxacin was relatively low. The proportions of cases representing infection and susceptibility to ceftazidime differed significantly based on genomic groups.
PubMed: 38842502
DOI: 10.1093/jac/dkae168 -
MBio Jun 2024expresses a type IV protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria and does so partly by secreting the effector TfcB. Here,...
expresses a type IV protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria and does so partly by secreting the effector TfcB. Here, we report the structure of TfcB, comprising an N-terminal domain similar to the catalytic domain of glycosyl hydrolase (GH-19) chitinases and a C-terminal domain for recognition and translocation by the T4SS. Utilizing a two-hybrid assay to measure effector interactions with the T4SS coupling protein VirD4, we documented the existence of five more T4SS substrates. One of these was protein 20845, an annotated nuclease. A mutant lacking the gene for 20845 was impaired for killing , , and . Moreover, the cloned 20845 gene conferred robust toxicity, with the recombinant being rescued when 20845 was co-expressed with its cognate immunity protein. The 20845 effector was an 899 amino-acid protein, comprised of a GHH-nuclease domain in its N-terminus, a large central region of indeterminant function, and a C-terminus for secretion. Engineered variants of the 20845 gene that had mutations in the predicted catalytic site did not impede , indicating that the antibacterial effect of 20845 involves its nuclease activity. Using flow cytometry with DNA staining, we determined that 20845, but not its mutant variants, confers a loss in DNA content of target bacteria. Database searches revealed that uncharacterized homologs of 20845 occur within a range of bacteria. These data indicate that the T4SS promotes interbacterial competition through the action of multiple toxic effectors, including a potent, novel DNase.IMPORTANCE is a multi-drug-resistant, Gram-negative bacterium that is an emerging pathogen of humans. Patients with cystic fibrosis are particularly susceptible to infection. In hospital water systems and various types of infections, co-exists with other bacteria, including other pathogens such as . We previously demonstrated that has a functional VirB/D4 type VI protein secretion system (T4SS) that promotes contact-dependent killing of other bacteria. Since most work on antibacterial systems involves the type VI secretion system, this observation remains noteworthy. Moreover, currently stands alone as a model for a human pathogen expressing an antibacterial T4SS. Using biochemical, genetic, and cell biological approaches, we now report both the discovery of a novel antibacterial nuclease (TfdA) and the first structural determination of a bactericidal T4SS effector (TfcB).
PubMed: 38832773
DOI: 10.1128/mbio.01198-24 -
Journal of Global Antimicrobial... May 2024Trimethoprim-sulfamethoxazole (TMP-SMX) has long been considered the treatment of choice for infections caused by Stenotrophomonas maltophilia. Levofloxacin has emerged...
BACKGROUND
Trimethoprim-sulfamethoxazole (TMP-SMX) has long been considered the treatment of choice for infections caused by Stenotrophomonas maltophilia. Levofloxacin has emerged as a potential option for treating these infections. This study aimed to evaluate the clinical outcomes in patients who received TMP-SMX versus levofloxacin for treating S. maltophilia infections.
METHODS
A retrospective, cohort study was conducted in 4 tertiary centres and included patients who were treated with either TMP-SMX or levofloxacin for infections caused by S. maltophilia. The main study outcomes were overall in-hospital mortality, 30-d mortality, and clinical cure. Safety outcomes were also evaluated. Multivariate analysis using logistic regression was used to control for the effect of the covariables.
RESULTS
We included 371 patients in this study, 316 received TMP-SMX and 55 patients received levofloxacin. A total of 70% were in the intensive care unit and 21% presented with bacteraemia. No statistically significant differences were observed in overall in-hospital mortality (52% vs. 40%; P = 0.113; odd ratio [OR], 1.59; 95% confidence interval [CI], 0.89-2.86), 30-d mortality (28% vs. 25%; P = 0.712; OR, 1.13; 95% CI, 0.59-2.18), or clinical cure (55% vs. 64%; P = 0.237; OR, 0.70; 95% CI, 0.37-1.31). Rates of acute kidney injury were comparable between the two groups (11% vs. 7%; P = 0.413).
CONCLUSION
Patients receiving levofloxacin for the treatment of infections caused by S. maltophilia demonstrated clinical outcomes similar to those receiving TMP-SMX. Our study suggests that levofloxacin can be a reasonable alternative to TMP-SMX to treat these infections.
PubMed: 38821443
DOI: 10.1016/j.jgar.2024.05.016 -
PeerJ 2024Confronting the environmental threat posed by textile dyes, this study highlights bioremediation as a pivotal solution to mitigate the impacts of Crystal Violet, a...
Confronting the environmental threat posed by textile dyes, this study highlights bioremediation as a pivotal solution to mitigate the impacts of Crystal Violet, a widely-utilized triphenylmethane dye known for its mutagenic and mitotic toxicity. We isolated and identified several bacterial strains capable of degrading Crystal Violet under various environmental conditions. Newly identified strains, including , sp., , , and demonstrated significant decolorization activity of Crystal Violet, complementing the already known capabilities of . Initial experiments using crude extracts confirmed their degradation potential, followed by detailed studies that investigated the impact of different pH levels and temperatures on some strains' degradation efficiency. Depending on the bacteria, the degree of activity change according to pH and temperature was different. At 37 °C, sp. and exhibited higher degradation activity compared to 25 °C, while and did not exhibit a statistically significant difference between the two temperatures. performed optimally at pH 8, while showed high activity at pH 5. s activity remained consistent across the pH range. These findings not only underscore the effectiveness of these bacteria as agents for Crystal Violet degradation but also pave the way for their application in large-scale bioremediation processes for the treatment of textile effluents, marking them as vital to environmental sustainability efforts.
Topics: Biodegradation, Environmental; Gentian Violet; Hydrogen-Ion Concentration; Temperature; Pseudomonas; Stenotrophomonas maltophilia; Coloring Agents; Bacteria
PubMed: 38818456
DOI: 10.7717/peerj.17442