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Heliyon Nov 2023Chitinases are hydrolytic enzymes that dissolve the glycosidic linkages in chitin. Chitin is a cell wall component of fungi and fund in exoskeleten of worms and...
Chitinases are hydrolytic enzymes that dissolve the glycosidic linkages in chitin. Chitin is a cell wall component of fungi and fund in exoskeleten of worms and arthropods. Chitinase has been applied in agriculture, as a biopesticide for the control of plant fungal infections, in medicine, and in waste management. This research aimed to isolate, screen, and identification of chitinase-producing bacteria from riverbank soils. Twenty nine chitinolytic bacteria were isolated from the river bank soil samples, from which 9 of them had strong chitinolytic properties. Chitinase production was determined by zones of hydrolysis produced after 96 h of incubation at 37 °C. The different bacterial isolates were characterized morphologically, microscopically, and biochemically and finally eight strain were identified at species level by Matrix Assisted Laser Desorption Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS). From the eight, bacterial isolates investigated in this study showed the highest chitinase enzyme activity (625 μg/mL) followed by with the enzyme activity of (553 μg/mL) and the least enzyme activity was recorded for (80 μg/mL). An incubation temperature of 45 °C, neutral pH and an incubation period of 96 h are found to be the optimum condition for the chitinase enzyme production from . The results of this study indicated the possibility of the production of chitinase from the chitinolytic bacterial isolates, which was highly useful for a variety of applications, including biocontrol of harmful insects and pathogenic fungi as well as in the biochemical, pharmaceutical, and medical sectors.
PubMed: 38027800
DOI: 10.1016/j.heliyon.2023.e21643 -
Clinical Case Reports Sep 2023is a Gram-negative bacterium, usually considered a nosocomial pathogen. Its role in community-acquired infections has been reported, but it is still not typically...
is a Gram-negative bacterium, usually considered a nosocomial pathogen. Its role in community-acquired infections has been reported, but it is still not typically included in differential diagnoses of patients not exposed to the healthcare system. Recently, some reports suggested that liver diseases might also act as a possible risk factor for community-acquired bloodstream infection. We report a case of a 77-year-old woman with a history of cirrhosis who was diagnosed with community-acquired bloodstream infection. not only causes hospital-acquired infections but is also emerging as a pathogen in community settings. Although community-onset infection is still rare and might have lower mortality, this antibiotic-resistant bacterial species should be considered a possible pathogen in patients with liver cirrhosis. Although trimethoprim-sulfamethoxazole is considered the first-line treatment, a study in vitro and a 4-year review of susceptibility in our institution found that the bacteria were more susceptible to minocycline than to trimethoprim-sulfamethoxazole. Therefore, minocycline might become the first-line treatment in the future.
PubMed: 37736476
DOI: 10.1002/ccr3.7920 -
Langmuir : the ACS Journal of Surfaces... Aug 2023Microbial nanotechnology is an expanding research area devoted to producing biogenic metal and metalloid nanomaterials (NMs) using microorganisms. Often, biogenic NMs...
Microbial nanotechnology is an expanding research area devoted to producing biogenic metal and metalloid nanomaterials (NMs) using microorganisms. Often, biogenic NMs are explored as antimicrobial, anticancer, or antioxidant agents. Yet, most studies focus on their applications rather than the underlying mechanism of action or toxicity. Here, we evaluate the toxicity of our well-characterized biogenic selenium nanoparticles (bSeNPs) produced by the strain SeITE02 against the model yeast comparing it with chemogenic SeNPs (cSeNPs). Knowing from previous studies that the biogenic extract contained bSeNPs in an organic material (OM) and supported here by Fourier transform infrared spectroscopy, we removed and incubated it with cSeNPs (cSeNPs_OM) to assess its influence on the toxicity of these formulations. Specifically, we focused on the first stages of the eukaryotic cell exposure to these samples─i.e., their interaction with the cell lipid membrane, which was mimicked by preparing vesicles from yeast polar lipid extract or phosphatidylcholine lipids. Fluidity changes derived from biogenic and chemogenic samples revealed that the bSeNP extract mediated the overall rigidification of lipid vesicles, while cSeNPs showed negligible effects. The OM and cSeNPs_OM induced similar modifications to the bSeNP extract, reiterating the need to consider the OM influence on the physical-chemical and biological properties of bSeNP extracts.
Topics: Selenium; Eukaryotic Cells; Saccharomyces cerevisiae; Nanoparticles; Lipids; Metal Nanoparticles
PubMed: 37462214
DOI: 10.1021/acs.langmuir.3c00718 -
Microbiology Spectrum Apr 2024complex (BCC) and are nosocomial pathogens that cause various infections and exhibit high resistance to multiple antimicrobial agents. In this study, we aimed to...
complex (BCC) and are nosocomial pathogens that cause various infections and exhibit high resistance to multiple antimicrobial agents. In this study, we aimed to develop a duplex droplet digital PCR (ddPCR) assay for detecting BCC and in bloodstream infections. We optimized the experimental conditions by setting the annealing temperature to 51°C and determining the optimal concentrations of primers and probes, as well as the thermal cycle numbers. The feasibility of the duplex ddPCR reaction system with the optimal conditions was established and verified through parallel reactions with reference strains of BCC and . The specificity of the assay, tested with 33 reference strains, was found to be 100%. The duplex ddPCR assay demonstrated good repeatability and could detect as low as 5.35 copies/reaction of BCC and 7.67 copies/reaction of . This level of sensitivity was consistent in the simulated blood and blood bottle samples. We compared nucleic acid extraction methods and found that the Chelex-100 boiling method and kit extraction method exhibited similar detection sensitivity, suggesting the potential application of the Chelex-100 boiling method in the ddPCR assay. In the clinical samples, the duplex ddPCR assay accurately detected BCC and in 58 cases. In conclusion, our study successfully developed a duplex ddPCR assay that provides accurate and convenient detection of BCC and in bloodstream infections.IMPORTANCE complex (BCC) and are implicated in a wide range of infections, including bloodstream infections (BSIs), pneumonia, and meningitis, and often exhibit high intrinsic resistance to multiple antimicrobial agents, limiting therapeutic options. The gold standard for diagnosing bloodstream infections remains blood culture. However, current blood culture detection and positivity rates do not meet the "rapid diagnosis" required for the diagnosis and treatment of critically ill patients with BSIs. The digital droplet PCR (ddPCR) method is a potentially more powerful tool in the diagnosis of BSIs compared to other molecular methods due to its greater sensitivity, specificity, accuracy, and reproducibility. In this study, a duplex ddPCR assay for the detection of BCC and in BSIs was developed.
Topics: Humans; Burkholderia cepacia complex; Stenotrophomonas maltophilia; Reproducibility of Results; Polymerase Chain Reaction; Sepsis; Anti-Infective Agents; Polystyrenes; Polyvinyls
PubMed: 38411052
DOI: 10.1128/spectrum.03569-23 -
Graefe's Archive For Clinical and... May 2024To describe the bacterial findings by a targeted sequencing approach from corneal samples of patients with microbial keratitis and factors influencing culture outcome of...
PURPOSE
To describe the bacterial findings by a targeted sequencing approach from corneal samples of patients with microbial keratitis and factors influencing culture outcome of indirectly inoculated corneal specimen.
METHODS
Prospective inclusion of patients fulfilling predefined criteria of microbial keratitis. Samples from the corneal lesion were collected and dispensed in liquid transport medium, from which both culture and targeted amplification and sequencing of the V3-V4 region of the 16S rRNA gene were carried out. Additional standard corneal culture from the corneal lesions was also performed. Factors influencing culture outcome of indirectly inoculated corneal samples were identified by a multivariate regression model incorporating quantitative data from sequencing.
RESULTS
Among the 94 included patients with microbial keratitis, contact lens wear (n = 69; 73%) was the most common risk factor. Contact lens wearers displayed significant differences in the bacterial community composition of the corneal lesion compared to no lens wearers, with higher abundance of Staphylococcus spp., Corynebacterium spp., and Stenotrophomonas maltophilia. Targeted sequencing detected a potential corneal pathogen in the highest proportional abundance among 9 of the 24 (38%) culture-negative patients with microbial keratitis. Age, bacterial density in the sample, and prior antibiotic treatment significantly influenced culture outcome of indirectly inoculated corneal samples.
CONCLUSION
Targeted sequencing may provide insights on pathogens in both culture negative episodes of microbial keratitis and among subgroups of patients with microbial keratitis as well as factors influencing culture outcome of indirectly inoculated corneal samples.
Topics: Humans; Prospective Studies; Ophthalmologists; RNA, Ribosomal, 16S; Keratitis; Bacteria; Microbiota; Eye Infections, Bacterial; Corneal Ulcer; Retrospective Studies; Risk Factors
PubMed: 37993692
DOI: 10.1007/s00417-023-06310-y -
Viruses Dec 2023was discovered as a soil bacterium associated with the rhizosphere. Later, was found to be a multidrug-resistant hospital-associated pathogen. Lytic bacteriophages are...
was discovered as a soil bacterium associated with the rhizosphere. Later, was found to be a multidrug-resistant hospital-associated pathogen. Lytic bacteriophages are prospective antimicrobials; therefore, there is a need for the isolation and characterization of new phages. The phage StenM_174 was isolated from litter at a poultry farm using a clinical strain of as the host. StenM_174 reproduced in a wide range of clinical and environmental strains of , mainly , and it had a podovirus morphotype. The length of the genomic sequence of StenM_174 was 42,956 bp, and it contained 52 putative genes. All genes were unidirectional, and 31 of them encoded proteins with predicted functions, while the remaining 21 were identified as hypothetical ones. Two tail spike proteins of StenM_174 were predicted using AlphaFold2 structural modeling. A comparative analysis of the genome shows that the phage StenM_174, along with the phages Ponderosa, Pepon, Ptah, and TS-10, can be members of the new putative genus in the family. In addition, the analyzed data suggest a new subfamily within this family.
Topics: Stenotrophomonas; Prospective Studies; Bacteriophages; Caudovirales; Stenotrophomonas maltophilia; Genome, Viral
PubMed: 38275953
DOI: 10.3390/v16010018 -
Cancer Reports (Hoboken, N.J.) Mar 2024Stenotrophomonas maltophilia is a bacterial pathogen that can be fatal in hospitalized and immunocompromised patients with mortality as high as 69%. Pediatric cancer...
BACKGROUND
Stenotrophomonas maltophilia is a bacterial pathogen that can be fatal in hospitalized and immunocompromised patients with mortality as high as 69%. Pediatric cancer patients often have risk factors that are common for this infection, making them particularly susceptible. Managing S. maltophilia is especially challenging as it has inherent resistance to several antibiotics. Furthermore, soft tissue infections in neutropenic patients may deviate from the typical clinical presentation of S. maltophilia.
CASE DETAILS
This case series describes an in-depth examination of three cases involving immunocompromised pediatric patients with S. maltophilia infections. Each case exhibited a distinct clinical presentation, encompassing infection of the blood, lung, and skin, which highlights the variability in which S. maltophilia manifests in immunocompromised pediatric patients. These patients were treated at MD Anderson Cancer Center (MDACC) from 2020 to 2023, unfortunately resulting in fatality.
CONCLUSIONS
The study aims to provide valuable insights and guidance for the management of patients with S. maltophilia infections. Emphasizing a heightened clinical suspicion will potentially lead to early initiation of directed therapy against S. maltophilia. Timely intervention may play a pivotal role in improving patient outcomes and reduce further burden to the healthcare system.
Topics: Humans; Child; Stenotrophomonas maltophilia; Anti-Bacterial Agents; Neoplasms; Risk Factors
PubMed: 38419283
DOI: 10.1002/cnr2.1982 -
Acute and Critical Care Nov 2023Stenotrophomonas maltophilia has been increasingly recognized as an opportunistic pathogen associated with high morbidity and mortality. Data on the prognostic factors...
BACKGROUND
Stenotrophomonas maltophilia has been increasingly recognized as an opportunistic pathogen associated with high morbidity and mortality. Data on the prognostic factors associated with S. maltophilia pneumonia in patients admitted to intensive care unit (ICU) are lacking.
METHODS
We conducted a retrospective analysis of data from 117 patients with S. maltophilia pneumonia admitted to the ICUs of two tertiary referral hospitals in South Korea between January 2011 and December 2022. To assess risk factors associated with in-hospital mortality, multivariable logistic regression analyses were performed.
RESULTS
The median age of the study population was 71 years. Ventilator-associated pneumonia was 76.1% of cases, and the median length of ICU stay before the first isolation of S. maltophilia was 15 days. The overall in-hospital mortality rate was 82.1%, and factors independently associated with mortality were age (odds ratio [OR], 1.05; 95% confidence interval [CI], 1.00-1.09; P=0.046), Sequential Organ Failure Assessment (SOFA) score (OR, 1.21; 95%; CI, 1.02-1.43; P=0.025), corticosteroid use (OR, 4.19; 95% CI, 1.26-13.91; P=0.019), and polymicrobial infection (OR, 95% CI 0.07-0.69). However, the impact of appropriate antibiotic therapy on mortality was insignificant. In a subgroup of patients who received appropriate antibiotic therapy (n=58), antibiotic treatment modality-related variables, including combination or empirical therapy, also showed no significant association with survival.
CONCLUSIONS
Patients with S. maltophilia pneumonia in ICU have high mortality rates. Older age, higher SOFA score, and corticosteroid use were independently associated with increased in-hospital mortality, whereas polymicrobial infection was associated with lower mortality. The effect of appropriate antibiotic therapy on prognosis was insignificant.
PubMed: 37994018
DOI: 10.4266/acc.2023.00682 -
Frontiers in Microbiology 2024Chronic infection with in persons with cystic fibrosis (pwCF) has been linked to an increased risk of pulmonary exacerbations and lung function decline. We sought to...
RATIONALE
Chronic infection with in persons with cystic fibrosis (pwCF) has been linked to an increased risk of pulmonary exacerbations and lung function decline. We sought to establish whether baseline sputum microbiome associates with risk of incident infection and persistence in pwCF.
METHODS
pwCF experiencing incident infections attending the Calgary Adult CF Clinic from 2010-2018 were compared with -negative sex, age (+/-2 years), and birth-cohort-matched controls. Infection outcomes were classified as persistent (when the pathogen was recovered in ≥50% of cultures in the subsequent year) or transient. We assessed microbial communities from prospectively biobanked sputum using V3-V4 16S ribosomal RNA (rRNA) gene sequencing, in the year preceding (Pre) ( = 57), at (At) ( = 22), and after (Post) ( = 31) incident infection. We verified relative abundance data using -specific qPCR and 16S rRNA-targeted qPCR to assess bioburden. Strains were typed using pulse-field gel electrophoresis.
RESULTS
Twenty-five pwCF with incident (56% female, median 29 years, median FEV 61%) with 33 total episodes were compared with 56 uninfected pwCF controls. Demographics and clinical characteristics were similar between cohorts. Among those with incident infection, sputum communities did not cluster based on infection timeline (Pre, At, Post). Communities differed between the infection cohort and controls ( = 56) based on Shannon Diversity Index (SDI, = 0.04) and clustered based on Aitchison distance (PERMANOVA, = 0.01) prior to infection. At the time of incident isolation, communities did not differ in SDI but clustered based on Aitchison distance (PERMANOVA, = 0.03) in those that ultimately developed persistent infection versus those that were transient. abundance within sputum was increased in samples from patients (Pre) relative to controls, measuring both relative ( = 0.004) and absolute ( = 0.001). Furthermore, abundance was increased in sputum at incident infection in those who ultimately developed persistent infection relative to those with transient infection, measured relatively ( = 0.04) or absolute ( = 0.04), respectively.
CONCLUSION
Microbial community composition of CF sputum associates with infection acquisition as well as infection outcome. Our study suggests sputum microbiome may serve as a surrogate for identifying infection risk and persistence risk.
PubMed: 38690371
DOI: 10.3389/fmicb.2024.1353145 -
Antimicrobial Resistance and Infection... May 2024Stenotrophomonas maltophilia is a gram-negative bacterium that can cause hospital infections and outbreaks within hospitals. This study aimed to evaluate an outbreak of...
BACKGROUND
Stenotrophomonas maltophilia is a gram-negative bacterium that can cause hospital infections and outbreaks within hospitals. This study aimed to evaluate an outbreak of Stenotrophomonas maltophilia, caused by ready-to-use commercial syringes containing liquid lithium and heparin for arterial blood gas collection in a university hospital.
METHODS
Upon detecting an increase in Stenotrophomonas maltophilia growth in blood cultures between 15.09.2021 and 19.11.2021, an outbreak analysis and a case-control study (52 patients for the case group, 56 patients for the control group) were performed considering risk factors for bacteremia. Samples from possible foci for bacteremia were also cultured. Growing bacteria were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The genetic linkage and clonal relationship isolates were investigated with pulsed-field gel electrophoresis (PFGE) in the reference laboratory.
RESULTS
In the case-control study, the odds ratio for the central venous catheter [3.38 (95% confidence interval [CI]: 1.444, 8.705 ; p = 0.006)], for surgery [3.387 (95% confidence interval [CI]: 1.370, 8.373 ; p = 0.008)] and for arterial blood gas collection history [18.584 (95% confidence interval [CI]:4.086, 84.197; p < 0.001)] were identified as significant risk factors. Stenotrophomonas maltophilia growth was found in ready-to-use commercial syringes used for arterial blood gas collection. Molecular analysis showed that the growths in the samples taken from commercial syringes and the growths from blood cultures were the same. It was decided that the epidemic occurred because the method for sterilization of heparinized liquid preparations were not suitable. After discontinuing the use of the kits with this lot number, the outbreak was brought under control.
CONCLUSIONS
According to our results, disposable or sterile medical equipment should be included as a risk factor in outbreak analyses. The method by which injectors containing liquids, such as heparin, are sterilized should be reviewed. Our study also revealed the importance of the cooperation of the infection control team with the microbiology laboratory.
Topics: Stenotrophomonas maltophilia; Humans; Disease Outbreaks; Case-Control Studies; Gram-Negative Bacterial Infections; Male; Female; Cross Infection; Middle Aged; Aged; Adult; Risk Factors; Bacteremia; Hospitals, University; Syringes; Electrophoresis, Gel, Pulsed-Field; Aged, 80 and over; Heparin
PubMed: 38764050
DOI: 10.1186/s13756-024-01410-8