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1.
Food Chem ; 366: 130608, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34454799

RESUMO

Hydrochar of waste walnut shells (WSH) was synthesized in the eco-friendly subcritical water medium (SWM) and its potential to fight against Klebsiella pneumoniae (K. pneumoniae), Staphylococcus aureus (S. aureus), Candida albicans (C. albicans) and Candida parapsilosis (C. parapsilosis) was investigated. Minimum Inhibitory Concentration (MIC) values of the WSH were 3.01 g/mL, 2.06 g/mL, 1.95 g/mL, and 3.12 g/mL for K. pneumoniae, S. aureus, C. albicans and C. parapsilosis, respectively. Survival of the pathogens was investigated by 3 min surface disinfection test exposure to WSH. While the highest inhibition was seen for C. parapsilosis (96.67%) on paper surface with 0.3 g/mL of bovine serum albumin (BSA), the lowest inhibition was determined for C. albicans (6.44%) on the plastic glass surface with 3 g/mL of BSA. An increase in protein, DNA, and potassium ion (K+) leakage was observed after microorganisms were incubated with WSH. This study provided an experimental basis for the practical application of WSH as a natural sanitizer agent.


Assuntos
Anti-Infecciosos , Juglans , Anti-Infecciosos/farmacologia , Candida albicans , Testes de Sensibilidade Microbiana , Staphylococcus aureus
2.
J Colloid Interface Sci ; 606(Pt 2): 1684-1694, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34500167

RESUMO

Bacterial infections are considered as a critical healthcare concern worldwide. Timely infection detection is crucial to effective antibiotic administration which can reduce the severity of infection and the occurrence of antibiotic resistance. We have developed label-free polydiacetylene (PDA) liposome-based colorimetric biosensor to detect and identify bacterial cultures at the genus and species level with naked eyes by simple color change. We found that among the various liposomal systems, moderate concentration of PDA, phospholipids and cholesterol in liposome assemblies can greatly influence the sensitivity to different bacteria, exhibiting unique chromatic properties of each bacterial strain. The strikingly different chromatic color change was due to the various mechanisms of interactions between bacterial toxins and biomimetic lipid bilayers. Furthermore, increase of cholesterol in liposome assemblies greatly enhanced the sensitivity of bacterial strains related to membrane destruction mediated by pore-formation mechanism such as S. aureus and E.coli, whereas the detection of the two bacterial strains was believed to rely on the specific recognition elements coupled with PDA moiety. As a proof of concept, a colorimetric finger-print array for distinguishing 6 bacterial species was studied. Particularly, the proposed bacterial detection platform is achieved through the interaction between bacterially secreted toxins and liposome bilayers instead of specific recognition of receptors-ligands. The results of both response time and sensitivity of label-free-liposome-based system show superior to previous reports on chromatic bacterial detection assays. By combing these results, the label-free-liposome-based colorimetric sensing platform shows great importance as a bacterial-sensing and discrimination platform.


Assuntos
Técnicas Biossensoriais , Colorimetria , Bactérias , Atenção à Saúde , Lipossomos , Polímero Poliacetilênico , Polímeros , Poli-Inos , Staphylococcus aureus
3.
Anal Chim Acta ; 1189: 339213, 2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34815035

RESUMO

Staphylococcus aureus is a common foodborne pathogen that can cause a suppurative infection after eating contaminated food. Detection of S. aureus plays an important role in the food industry. In this study, a strategy for the detection of S. aureus using magnetic separation (MS) technology combined with rolling circle amplification (MS-RCA) was proposed. The strategy used antibiotics to capture bacteria and employed RCA products as signal output probes. Vancomycin (Van), as a commonly used antibiotic, can recognize peptidoglycan on the cell wall of Gram-positive bacteria and can effectively identify target bacteria. Therefore, we prepared BSAylated-Van functionalized magnetic beads (Van-MBs) for the pre-enrichment of S. aureus. To ensure the selectivity of this method, we used biotin-pig IgG to bind S. aureus. In addition, to amplify the output signal of the MS-RCA strategy, we introduced streptavidin (SA) and successfully obtained the Van-MBs@S. aureus@biotin-pig IgG@SA@biotin-RCA probe complex and used the biotin-avidin-system (BAS) by combining magnetic separation technology and RCA technology to realize the enrichment and specific detection of S. aureus. Furthermore, by optimizing the experimental conditions such as the magnetic separation time and the amount of Van-MBs, the detection performance of this method was improved. Under the optimal conditions, the detection limit of this method for S. aureus was 3.3 × 102 CFU/mL in fruit juice, and it was less affected by other bacteria.


Assuntos
Infecções Estafilocócicas , Staphylococcus aureus , Animais , Sucos de Frutas e Vegetais , Técnicas de Amplificação de Ácido Nucleico , Infecções Estafilocócicas/diagnóstico , Estreptavidina , Suínos , Vancomicina
4.
Food Chem ; 370: 131025, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34509147

RESUMO

Grape marc is an underutilised waste material that poses significant environmental issues. This study offers the first proof-of-concept investigation into the polymerisation of both crude and purified Sauvignon blanc grape marc extracts using the diacyl chlorides terephthaloyl chloride, succinyl chloride, adipoyl chloride, sebacoyl chloride, and the tartaric acid derivative (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dicarbonyl dichloride to obtain new materials, in what to the best of our knowledge is the first reported example of a direct polymerisation of an agricultural waste extract. A total of 26 novel materials were prepared. It has also shown that quercetin, a phenolic monomer found in grape marc extracts, can be polymerised with (4R,5R)-2,2-dimethyl-1,3-dioxolane-4,5-dicarbonyl dichloride to give a polymer that shows activity towards S. aureus.


Assuntos
Vitis , Agricultura , Antibacterianos , Fenóis , Staphylococcus aureus
5.
Spectrochim Acta A Mol Biomol Spectrosc ; 264: 120283, 2022 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-34428635

RESUMO

In this work, we report in situ nonlinear microscopic images on plasmon-enhanced coherent anti-Stokes Raman scattering (CARS) and plasmon-Induced two-photon excited fluorescence (TPEF)of non-fluorescent microorganism. Our unique synthesized Au@Ag nanorods provide with two distinct surface-plasmon resonance (SPR) at 400 and 800 nm, respectively, which can efficiently induce linear fluorescence signals of E. coli but also enhance the nonlinear optical spectroscopy signals of TPEF, and coherent anti-Stokes Raman scattering (CARS) imaging of E. coli and S. aureus. Furthermore, calculations with complete active space self-consistent field (CASSCF) reveals the hot electrons of SPs can efficiently induce the biological fluorescence of non-fluorescent flavin nucleotides on the surface of E. coli. This novel mechanism is expected to guide the development and application of new microbial detection reagents. Gram-negative and Gram-positive bacteria can be well distinguished by nonlinear microscopic imaging of the CARS signal at 1589 cm-1. Benefit by the strong penetrability of non-linear optical signals, it is expected to realize in situ real-time detection and classification of pathogenic microbial infections in vivo.


Assuntos
Escherichia coli , Análise Espectral Raman , Fótons , Coloração e Rotulagem , Staphylococcus aureus
6.
Chemosphere ; 287(Pt 2): 132131, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34492413

RESUMO

Ion exchange membranes (IEMs) are widely used in water treatment applications such as electrodialysis. However, the exploration of IEMs as effective antibacterial food contact materials (e.g., food packaging membranes) against pathogenic bacteria to ensure food safety has not been reported. Here, we report a simple but effective method to prepare high performance antibacterial membranes via ion exchange coupled with in-situ reduction. The general membrane properties are characterized using SEM, EDS, FTIR, XPS, XRD, DSC, TGA, water uptake, etc. The distribution of silver and copper in the membranes are generally in line with the distribution of sulfur, indicating that the antibacterial ions are introduced into the membranes via ion exchange and are bonded with the sulfonate groups in the membranes. The antibacterial performance is investigated using zone of inhibition tests and continuous bacteria growth inhibition tests. All of the prepared membranes show obvious antibacterial activities compared to the bare cation exchange membranes. The diameters of inhibition zone against Staphylococcus aureus (S. aureus) are all larger than those of Escherichia coli (E. coli), indicating that the prepared membranes are more efficient in inhibiting S. aureus compared to E. coli. Furthermore, the silver-based membrane shows more sustainable antibacterial activities compared to the copper-based membrane. Especially, the results clearly reveal that the silver-based membrane is capable of killing bacteria instead of just inhibiting the growth of bacteria. We have shown for the first time that membranes derived from IEMs have the potential as food contact materials to inhibit the growth of pathogenic bacteria so as to eliminate the risk of bacterial infections and meanwhile delay food spoilage due to bacteria growth.


Assuntos
Nanopartículas Metálicas , Prata , Antibacterianos/farmacologia , Cobre , Escherichia coli , Troca Iônica , Testes de Sensibilidade Microbiana , Prata/farmacologia , Staphylococcus aureus
7.
Chemosphere ; 287(Pt 2): 132137, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34496335

RESUMO

Uranium extraction and recovery play a critical role in guaranteeing the sustainable nuclear energy supply and protecting the environmental safety. The ideal uranium sorbents possess high adsorption capacity, excellent selectivity and reusability, as well as outstanding antimicrobial property, which are greatly desired for the real application of uranium extraction from seawater. To address this challenge, a novel magnetic core-shell adsorbent was designed and fabricated by a facile method. The obtained amidoximed Fe3O4@TiO2 particles (Fe3O4@TiO2-AO) achieved equilibrium in 2 h and the maximum adsorption capacity calculated from Langmuir model is 217.0 mg/g. The adsorption kinetics followed the pseudo-second-order model. Meanwhile, the Fe3O4@TiO2-AO exhibited great selectivity when competitive metal ions and anions coexisted. In addition, the magnetic Fe3O4@TiO2-AO could be conveniently separated and collected by an external magnetic field, the regeneration efficiency maintained at 78.5% even after ten adsorption-desorption cycles. In natural seawater, the uranium uptake reached 87.5 µg/g in 33 days. Furthermore, the TiO2 contained adsorbent showed effective photo induced bactericidal properties against both E. coli and S. aureus. The Fe3O4@TiO2-AO with great U(VI) adsorption performance is highly promising in uranium extraction and reclamation.


Assuntos
Urânio , Adsorção , Antibacterianos , Escherichia coli , Oximas , Água do Mar , Staphylococcus aureus , Titânio
8.
Chemosphere ; 287(Pt 3): 132271, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34547560

RESUMO

In this study, novel biogenic silver (AgNPs) and gold nanoparticles (AuNPs) were developed using a green approach with Ganoderma lucidum (GL) extract. The optimization of synthesis conditions for the best outcomes was conducted. The prepared materials were characterized and their applicability in catalysis, antibacterial and chemical sensing was comprehensively evaluated. The GL-AgNPs crystals were formed in a spherical shape with an average diameter of 50 nm, while GL-AuNPs exhibited multi-shaped structures with sizes ranging from 15 to 40 nm. As a catalyst, the synthesized nanoparticles showed excellent catalytic activity (>98% in 9 min) and reusability (>95% after five recycles) in converting 4-nitrophenol to 4-aminophenol. As an antimicrobial agent, GL-AuNPs were low effective in inhibiting the growth of bacteria, while GL-AgNPs expressed strong antibacterial activity against all the tested strains. The highest growth inhibition activity of GL-AgNPs was observed against B. subtilis (14.58 ± 0.35 mm), followed by B. cereus (13.8 ± 0.52 mm), P. aeruginosa (12.38 ± 0.64 mm), E. coli (11.3 ± 0.72 mm), and S. aureus (10.41 ± 0.31 mm). Besides, GL-AgNPs also demonstrated high selectivity and sensitivity in the colorimetric detection of Fe3+ in aqueous solution with a detection limit of 1.85 nM. Due to the suitable thickness of the protective organic layer and the appropriate particle size, GL-AgNPs validated the triple role as a high-performance catalyst, antimicrobial agent, and nanosensor for environmental monitoring and remediation.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Antibacterianos/farmacologia , Catálise , Colorimetria , Escherichia coli , Compostos Férricos , Ouro , Química Verde , Íons , Testes de Sensibilidade Microbiana , Extratos Vegetais , Prata , Staphylococcus aureus
9.
Int J Food Microbiol ; 361: 109461, 2022 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-34742144

RESUMO

The main objective of this study was to isolate and identify Staphylococcus aureus from retail raw red meat samples and evaluate their enterotoxin gene and antibiotic resistance profiles. A total of 452 retail raw meat samples, including beef (n = 200), sheep (n = 125), and lamb (n = 127) randomly purchased from various supermarkets and butchers in Ankara between July 2019 and November 2020, were tested for the prevalence of S. aureus. The S. aureus strain was identified using morphological and molecular (16S rRNA and nuc gene) methods. Moreover, nine Staphylococcal enterotoxin (SE) genes were screened using polymerase chain reaction. Antibiotic resistance of S. aureus was determined using the phenotypic disc diffusion method. The overall prevalence of S. aureus among screened samples was 21.23%. Additionally, 65.62% of S. aureus strains contained SE gene regions. The predominant SEs in the S. aureus strains were sea (50.79%), followed by sed (25.39%) and seb (23.80%). However, sec, see, seg, seh, sei, and sej genes were never detected. A substantial proportion (40-100%) of the isolates were found resistant to kanamycin, telithromycin, penicillin G, streptomycin, erythromycin, cloxacillin, ampicillin, pristinamycin, nalidixic acid, azithromycin, and ciprofloxacin. Multi-drug resistance (MDR) was observed in 96.87% of the S. aureus strains. These results show a low prevalence of S. aureus in raw red meat samples in Turkey. However, a high rate of SEA raises serious health concerns. Due to the high levels of MDR observed in this study, there is a need to strictly control antibiotic use in animals in Turkey.


Assuntos
Carne Vermelha , Infecções Estafilocócicas , Animais , Bovinos , Resistência Microbiana a Medicamentos , Enterotoxinas/genética , Microbiologia de Alimentos , Carne , Prevalência , RNA Ribossômico 16S , Ovinos , Staphylococcus aureus/genética , Turquia
10.
Chemosphere ; 287(Pt 1): 132030, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34461338

RESUMO

A biocomposite (PN-Fe3O4-PEI) was synthesized via the chemical modification of peanut husk (a low-cost adsorbent) with Fe3O4 particles and polyethyleneimine under benign environmental conditions. The modification agents used in this study were observed to overcome the challenges associated with the use pristine peanut husk with a concomitant enhancement in its efficiency as an adsorbent. Results from the characterization studies employed in this study confirmed PN-Fe3O4-PEI to be a crystalline magnetic adsorbent with a mesoporous structure. The adsorption property of the developed material (PN-Fe3O4-PEI) for wastewater treatment was investigated using Chromium (VI), Phosphates (PO43-) and Congo red (CR) as model pollutants. Using the batch method, PN-Fe3O4-PEI exhibited a maximum monolayer adsorption capacity of 58.4, 13.5 and 71.3 mg g-1 for Cr(VI), PO43- (as P g L-1) and CR, respectively and was dependent on temperature and initial adsorbate concentration. Kinetic studies revealed that the Elovich equation, the pseudo-second order kinetic model and double constant equation well described the uptake of Cr(VI), PO43- and CR onto PN-Fe3O4-PEI, respectively. These results may confirm the uptake of these pollutants to be mainly driven by chemical forces. In addition, PN-Fe3O4-PEI was observed to be efficient for the decontamination of the studied pollutants in real water samples as well as exhibit antibacterial properties towards the growth of S. aureus. These properties of PN-Fe3O4-PEI with its other excellent features such as high stability in solution, good regeneration properties and its facile retrieval from the solution using a magnet promote its suitability for practical wastewater treatment.


Assuntos
Vermelho Congo , Poluentes Químicos da Água , Adsorção , Antibacterianos , Arachis , Cromo , Concentração de Íons de Hidrogênio , Cinética , Fenômenos Magnéticos , Fosfatos , Staphylococcus aureus , Poluentes Químicos da Água/análise
11.
Braz J Biol ; 83: e243332, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34730611

RESUMO

The present study was aimed to manifest the antibacterial and antifungal activity of methanolic extracts of Salix alba L. against seven Gram-positive and Gram-negative bacterial pathogens e.g. Streptococcus pyogenes, Staphylococcus aureus (1), S. aureus (2), Shigella sonnei, Escherichia coli (1), E. coli (2) and Neisseria gonorrhoeae and three fungal isolates from the air such as Aspergillus terreus, A. ornatus, and Rhizopus stolonifer. Two different serotypes of S. aureus and E. coli were used. The agar well-diffusion method results showed the dose-dependent response of plant extracts against bacterial and fungal strains while some organisms were found resistant e.g. E. coli (1), S. sonnei, A. terreus and R. stolonifer. The highest antibacterial activity was recorded at 17.000±1.732 mm from 100 mg/mL of leaves methanolic extracts against S. pyogenes while the activity of most of the pathogens decreased after 24 h of incubation. The highest antifungal activity was reported at 11.833±1.0 mm against A. ornatus at 50 mg/mL after 48 h of the incubation period. These experimental findings endorse the use of S. alba in ethnopharmacological formulations and suggest the use of methanolic extracts of the said plant to develop drugs to control the proliferation of resistant disease causing pathogenic microbes.


Assuntos
Antifúngicos , Salix , Antibacterianos/farmacologia , Antifúngicos/farmacologia , Aspergillus , Escherichia coli , Metanol , Testes de Sensibilidade Microbiana , Extratos Vegetais/farmacologia , Rhizopus , Staphylococcus aureus
12.
An Acad Bras Cienc ; 93(suppl 4): e20210550, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34730626

RESUMO

The aim of this study was to investigate the combined effect of carvacrol, thymol and nisin against Staphylococcus aureus and the combined effect of carvacrol and thymol against Salmonella Enteritidis. Minimum inhibitory concentrations (MIC) of carvacrol, thymol, and nisin for S. aureus were 200, 150 and 30 µg/mL, respectively. MIC of carvacrol and thymol for Salmonella Enteritidis was 200 µg/mL. A factorial method of independent variables was then used to study the combined effect of antimicrobials. Results showed that combinations of carvacrol-thymol-nisin (reduction of 1.2 log CFU/mL for MIC and 4.98 log CFU/mL for 2MIC), carvacrol-thymol (reduction of 1.33 log CFU/mL for 2MIC), nisin-thymol (reduction of 3.52 log CFU/mL for 2MIC) and nisin-carvacrol (reduction of 3.41 log CFU/mL for 2MIC) attained a significant inhibition of S. aureus. Similarly, there was significant reduction of Salmonella Enteritidis due to combined effect of thymol-carvacrol (reduction of 4.5 log CFU/mL for MIC and inhibition below detection limit for 2MIC). Therefore, the combinations of natural antimicrobials described in this work showed potential to be used as an additional barrier for food safety.


Assuntos
Nisina , Timol , Antibacterianos/farmacologia , Cimenos , Testes de Sensibilidade Microbiana , Monoterpenos/farmacologia , Nisina/farmacologia , Salmonella enteritidis , Staphylococcus aureus , Timol/farmacologia
13.
BMC Genomics ; 22(1): 796, 2021 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-34740333

RESUMO

BACKGROUND: Mastitis is an economically important disease of dairy cows with Staphylococcus aureus a major cause worldwide. Challenge of Holstein-Friesian cows demonstrated that S. aureus strain MOK124, which belongs to Clonal Complex (CC)151, caused clinical mastitis, while strain MOK023, belonging to CC97, caused mild or subclinical mastitis. The aim of this study was to elucidate the molecular mechanisms of the host immune response utilising a transcriptomic approach. Milk somatic cells were collected from cows infected with either S. aureus MOK023 or MOK124 at 0, 24, 48, 72 and 168 h post-infection (hpi) and analysed for differentially expressed (DE) genes in response to each strain. RESULTS: In response to MOK023, 1278, 2278, 1986 and 1750 DE genes were found at 24, 48, 72 and 168 hpi, respectively, while 2293, 1979, 1428 and 1544 DE genes were found in response to MOK124 at those time points. Genes involved in milk production (CSN1, CSN10, CSN1S2, CSN2, a-LACTA and PRLR) were downregulated in response to both strains, with a more pronounced decrease in the MOK124 group. Immune response pathways such as NF-κB and TNF signalling were overrepresented in response to both strains at 24 hpi. These immune pathways continued to be overrepresented in the MOK023 group at 48 and 72 hpi, while the Hippo signalling, extracellular matrix interaction (ECM) and tight junction pathways were overrepresented in the MOK124 group between 48 and 168 hpi. Cellular composition analysis demonstrated that a neutrophil response was predominant in response to MOK124, while M1 macrophages were the main milk cell type post-infection in the MOK023 group. CONCLUSIONS: A switch from immune response pathways to pathways involved in maintaining the integrity of the epithelial cell layer was observed in the MOK124 group from 48 hpi, which coincided with the occurrence of clinical signs in the infected animals. The higher proportion of M1 macrophages in the MOK023 group and lack of substantial neutrophil recruitment in response to MOK023 may indicate immune evasion by this strain. The results of this study highlight that the somatic cell transcriptomic response to S. aureus is dependent on the genotype of the infecting strain.


Assuntos
Mastite Bovina , Infecções Estafilocócicas , Animais , Bovinos , Feminino , Genótipo , Mastite Bovina/genética , Leite , Infecções Estafilocócicas/genética , Infecções Estafilocócicas/veterinária , Staphylococcus aureus/genética , Transcriptoma
14.
Am J Case Rep ; 22: e934092, 2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34750340

RESUMO

BACKGROUND Hemophagocytic lymphohistiocytosis (HLH) is a rare clinical syndrome characterized by dysregulated immune system activation and hyperinflammation. Primary HLH is inherited and almost exclusively seen in childhood, while secondary HLH is mainly seen in adults and has a wide variety of triggering factors, including infection, malignancy, autoimmune disease, and immunosuppression. Due to nonspecific presentation, the differential diagnosis for HLH is equally wide. We present a case of secondary HLH involving undiagnosed systemic lupus erythematosus and bacteremia. CASE REPORT A 43-year-old man with a history of discoid lupus presented with 1 month of weakness, epistaxis, shortness of breath, anorexia, and weight loss. He took no medications and did not follow with a primary care physician. Workup revealed leukopenia and thrombocytopenia, severely elevated ferritin, severe acute kidney injury, class II lupus nephritis on renal biopsy, hemophagocytic histiocytes on bone marrow biopsy, and other findings of end-organ damage. Blood cultures grew methicillin-sensitive Staphylococcus aureus (MSSA). Diagnosis of HLH occurred on the third day of admission. Our patient improved rapidly on high-dose corticosteroids, hydroxychloroquine, anakinra, tocilizumab, and low-dose etoposide as well as concomitant antibiotic therapy. CONCLUSIONS Despite having a diagnosis of discoid lupus, our patient was not established with a primary care physician and did not take any medications. This resulted in unknown smoldering systemic lupus erythematosus, which, possibly in conjunction with bacteremia, triggered a nearly fatal disease. We discuss the importance of primary care in disease management, the differentiation of sHLH from other diagnoses, HLH treatment, and the laboratory evaluation of sHLH.


Assuntos
Bacteriemia , Lúpus Eritematoso Discoide , Lúpus Eritematoso Sistêmico , Linfo-Histiocitose Hemofagocítica , Adulto , Bacteriemia/complicações , Bacteriemia/diagnóstico , Bacteriemia/tratamento farmacológico , Humanos , Lúpus Eritematoso Sistêmico/complicações , Lúpus Eritematoso Sistêmico/diagnóstico , Linfo-Histiocitose Hemofagocítica/complicações , Linfo-Histiocitose Hemofagocítica/diagnóstico , Masculino , Staphylococcus aureus
15.
Clin Lab ; 67(11)2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34758222

RESUMO

BACKGROUND: In sub-Saharan Africa, bacterial bloodstream infection is the most common cause of morbidity and mortality. Regular antimicrobial surveillance is required to understand resistance development and to inform clinicians and policymakers on best empiric antibiotic choice, such type of data are scarce in the study area. This study aimed to determine bacterial profiles and their antibiotic susceptibility patterns from patients with suspected septicemia at the University of Gondar comprehensive specialized hospital, northwest Ethiopia, over a six-year period. METHODS: We carried out a six-year (January 2, 2012, to January 1, 2018) retrospective analysis of blood cultures from patients with suspected septicemia. Laboratory report data were used to determine patient demographic, bacterial profiles, and antimicrobial resistance patterns. A total of 2,404 blood cultures were processed during the study period. Data were analyzed using SPSS version 20 software and the results were summarized using tables and graphs. RESULTS: Of the 2,404 blood cultures, 489 (20.7%, [95% CI, 19.2 - 22.3%]) bacteria isolates were obtained. The most common isolates were Staphylococcus aureus (215; 43.2%), followed by Klebsiella spp (67; 13.5%), coagulase-negative staphylococcus (62; 12.4%), Escherichia coli (38; 7.6%), viridans streptococci (25; 5%), Citrobacter spp (17; 3.4%), Enterobacter spp (15; 3%), and Streptococcus pneumoniae (12; 2.4%). Methicillin-resistant S. aureus isolation rate was 21/44 (47.7%). Gram-positive and negative bacteria showed high resistance to older antimicrobials, namely ampicillin, erythromycin, tetracycline, gentamicin, and trimethoprim-sulphamethoxazole. Gram-negative bacteria had a high level of resistance to 3rd generation cephalosporins, but both Gram-positive and negative bacteria were susceptible to ciprofloxacin. CONCLUSIONS: S. aureus, CoNS, S. pneumoniae, Klebsiella spp and E. coli remain the most important bacteria responsible for bloodstream infection in this study. Those pathogens showed a high rate of resistance to old antibiotics. Among the tested antimicrobials, ciprofloxacin was found to be the most effective drug to inhibit the in-vitro growth of both Gram-positive and negative bacteria. Therefore, there is a need for continuous screening of AMR from blood cultures to control the spread of drug resistant isolates in the study area.


Assuntos
Anti-Infecciosos , Staphylococcus aureus Resistente à Meticilina , Sepse , Adulto , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bactérias , Criança , Farmacorresistência Bacteriana , Escherichia coli , Etiópia/epidemiologia , Humanos , Testes de Sensibilidade Microbiana , Estudos Retrospectivos , Staphylococcus aureus
16.
Middle East Afr J Ophthalmol ; 28(2): 116-122, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34759670

RESUMO

PURPOSE: Certain ocular resident or pathogenic microbes may remain viable in the presence of multi-purpose disinfectant solutions (MPDSs), subsequently developing biofilms inside contact lens storage cases (CLSCs) which pose a risk of infection to wearers. This study evaluated the formation of ocular microbiota biofilms exposed to three top selling MPDS. METHODS: Crystal violet assay was carried out for the verification of biofilm formation. The in vitro assays evaluated Pseudomonas aeruginosa UFPEDA 416 and Staphylococcus aureus UFPEDA 02 exposure of 48 h to MPDS, as well as the use of 40 KHz ultrasound at the beginning and with 24 h immersion in the MPDS. Subsequently, in vivo assays evaluated the formation of microbial biofilms on the CLSC walls containing silicone-hydrogel contact lenses immersed in MPDS from 15 healthy volunteer patients, who had been wearing the lenses for 7 days. RESULTS: Biofilms were inhibited by 26%-98% in the in vitro assays, with a statistically significant difference only for P. aeruginosa UFPEDA 416 exposed to diluted MPDS. Most inhibitions occurred moderately and weakly. In addition, adherent cells were detected in more than 90% of the tests. Biofilm was not inhibited in more than one third of the results, nor was it disturbed, especially with the ultrasound treatments. The average of obtained optical densities at 590 nm was between 0.6 and 0.8 in the in vivo assays. The results were similar between the CLSC right and left wells. There was a correlation between microbial biofilm formation and the type of MPDS tested, with statistical difference between the three treatments. CONCLUSION: MPDS promoted a partial inhibition of microbial biofilm formation but only one MPDS proved to be more effective in vitro and in vivo. This study, however, could not distinguish the effect of possible errors in the good hygiene practices of the users.


Assuntos
Soluções para Lentes de Contato , Lentes de Contato , Biofilmes , Soluções para Lentes de Contato/farmacologia , Humanos , Pseudomonas aeruginosa , Staphylococcus aureus
17.
Anal Chim Acta ; 1187: 339155, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34753577

RESUMO

A novel surface-enhanced Raman scattering (SERS)-based analytical technique was proposed to simultaneously detect two highly pathogenic bacteria, namely, Staphylococcus aureus (S. aureus) and Listeria monocytogenes (L. mono) by using a dual-recognition pattern with wheat germ agglutinin (WGA) and nucleic acid aptamers. WGA was modified onto Fe3O4@Au magnetic nanoparticles (MNPs) for the efficient capture of S. aureus and L. mono in complex samples (orange juice, extracts of lettuce, and human urine) within 15 min. The streptavidin (SA)/aptamers co-functionalized SERS tags were fabricated by covalent attaching two different Raman reporters and SA molecules onto 45 nm Au NPs and then conjugated with two biotin-aptamers that specifically bind to their target bacteria with high affinity and stability. The combined use of high-sensitive SERS tags, WGA-mediated magnetic enrichment, and SA-mediated aptamer conjugation remarkably improved the assay sensitivity. Under optimized conditions, the developed SERS biosensor can simultaneously detect the two target bacteria with high detection sensitivity (<6 cells/mL), favorable linear relation (10-107 cells/mL), and high accuracy (recovery rate <7.03%). Therefore, the proposed SERS platform is rapid, sensitive, easy to use, and thus show potential as a tool for the timely identification of pathogenic bacteria in real samples.


Assuntos
Aptâmeros de Nucleotídeos , Técnicas Biossensoriais , Listeria monocytogenes , Nanopartículas Metálicas , Ouro , Humanos , Fenômenos Magnéticos , Análise Espectral Raman , Staphylococcus aureus , Estreptavidina , Aglutininas do Germe de Trigo
18.
Zhonghua Shao Shang Za Zhi ; 37(11): 1024-1035, 2021 Nov 20.
Artigo em Chinês | MEDLINE | ID: mdl-34794254

RESUMO

Objective: To study the effects of reactive oxygen species (ROS)-responsive antibacterial microneedles (MNs) on the full-thickness skin defect wounds with bacterial colonization in diabetic mice. Methods: Experimental research methods were adopted. The ROS-responsive crosslinker N1-(4-boronobenzyl)-N3-(4-boronophenyl)-N1, N1, N3, N3-tetramethylpropane-1,3-diaminium (TSPBA) was first synthesized, and then the polyvinyl alcohol (PVA)-TSPBA MNs, PVA-ε-polylysine (ε-PL)-TSPBA MNs, PVA-TSPBA-sodium hyaluronate (SH) MNs, and PVA-ε-PL-TSPBA-SH MNs were prepared by mixing corresponding ingredients, respectively. The PVA-TSPBA MNs were placed in pure phosphate buffer solution (PBS) and PBS containing hydrogen peroxide, respectively. The degradation of MNs immersed for 0 (immediately), 3, 7, and 10 days was observed to indicate their ROS responsiveness. The standard strains of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) cultured in Luria-Bertani medium containing hydrogen peroxide were divided according to the random number table (the same grouping method below) into blank control group (without any treatment, the same below) and 0 g/L ε-PL group, 1.0 g/L ε-PL group, 5.0 g/L ε-PL group, and 10.0 g/L ε-PL group with which PVA-ε-PL-TSPBA MNs containing the corresponding concentration of ε-PL were co-cultured, respectively. Bacterial growth was observed after 24 h of culture, and the relative survival rate of bacteria was calculated (n=3). The mouse fibroblast cell line 3T3 cells at logarithmic growth stage (the same growth stage below) were divided into blank control group and 0 g/L ε-PL group, 1.0 g /L ε-PL group, 5.0 g /L ε-PL group, and 10.0 g /L ε-PL group in which cells were cultured in medium with the extract from PVA-ε-PL-TSPBA MNs containing the corresponding concentration of ε-PL, respectively. Cell growth was observed after 24 h of culture by optical microscopy, and the relative survival rate of cells was detected and calculated by cell counting kit 8 (CCK-8) assay to indicate the cytotoxicity (n=6). Both PVA-TSPBA MNs and PVA-TSPBA-SH MNs were taken, the morphology of the two kinds of MNs was observed by optical microscopy, and the mechanical properties of the two kinds of MNs were tested by microcomputer controlled electronic universal testing machine (denoted as critical force, n=6). Six male BALB/c mice aged 6-8 weeks (the same gender and age below) were divided into PVA-TSPBA group and PVA-TSPBA-SH group, with 3 mice in each group. After pressing the skin on the back of mice vertically with the corresponding MNs for 1 minute, the skin condition was observed at 0, 10, and 20 min after pressing. Another batch of 3T3 cells were divided into blank control group, 0 g/L ε-PL group and simple 5.0 g/L ε-PL group which were cultured with the extract of PVA-ε-PL-TSPBA MNs containing the corresponding concentration of ε-PL, and 5.0 g/L ε-PL+SH group which were cultured with the extract of PVA-ε-PL-TSPBA-SH MNs with 5.0 g/L ε-PL. The CCK-8 assay was performed to detect and calculate the relative survival rate of cells cultured for 24, 48, and 72 h to indicate the cell proliferation activity (n=6). Eighteen BALB/c mice were induced into diabetic mice model by high-sugar and high-fat diet combined with streptozotocin injection and then divided into sterile dressing group, 0 g/L ε-PL+SH group, and 5.0 g/L ε-PL+SH group, with 6 mice in each group. A full-thickness skin defect wound was made on the back of each mouse, and S. aureus solution was added to make a full-thickness skin defect wound with bacterial colonization model for diabetic mouse. The wounds of mice in 0 g/L ε-PL+SH group and 5.0 g/L ε-PL+SH group were covered with PVA-ε-PL-TSPBA-SH MNs with the corresponding concentration of ε-PL, and the wounds of mice in the 3 groups were all covered with sterile surgical dressings. The wound healing was observed on post injury day (PID) 0, 3, 7, and 12, and the wound healing rate on PID 3, 7, and 12 was calculated. On PID 12, the skin tissue of the wound and the wound margin were stained with hematoxylin and eosin to observe the growth of new epithelium and the infiltration of inflammatory cells. Data were statistically analyzed with one-way analysis of variance, analysis of variance for repeated measurement, Mann-Whitney U test, and Bonferroni test. Results: With the extension of the immersion time, the PVA-TSPBA MNs in PBS containing hydrogen peroxide gradually dissolved and completely degraded after 10 days of immersion. The PVA-TSPBA MNs in pure PBS only swelled but did not dissolve. After 24 h of culture, there was no growth of S. aureus in 5.0 g/L ε-PL group or 10.0 g/L ε-PL group, and there was no growth of E. coli in 10.0 g/L ε-PL group. The relative survival rate of S. aureus was significantly lower in 1.0 g/L ε-PL group, 5.0 g/L ε-PL group, and 10.0 g/L ε-PL group than in blank control group (P<0.05 or P<0.01). The relative survival rate of E. coli was significantly lower in 5.0 g/L ε-PL group and 10.0 g/L ε-PL group than in blank control group (P<0.01). After 24 h of culture, the cells in blank control group, 0 g/L ε-PL group, 1.0 g/L ε-PL group, 5.0 g/L ε-PL group, and 10.0 g/L ε-PL group all grew well, and the relative survival rate of cells was similar among the groups (P>0.05). The needle bodies of PVA-TSPBA MNs and PVA-TSPBA-SH MNs were both quadrangular pyramid-shaped and neatly arranged, and the needle bodies of PVA-TSPBA-SH MNs was more three-dimensional and more angular. The critical force of PVA-TSPBA-SH MNs was significantly higher than that of PVA-TSPBA MNs (Z=3.317, P<0.01). The MNs in PVA-TSPBA+SH group penetrated the skin of mice at 0 min after pressing, and the pinholes partially disappeared after 10 min and completely disappeared after 20 min, while the MNs in PVA-TSPBA group failed to penetrate the skin of mice. After 24, 48, and 72 h of culture, the proliferation activity of the cells in 5.0 g/L ε-PL+SH group was significantly higher than that of blank control group (P<0.05 or P<0.01). In sterile dressing group, the wounds of mice healed slowly and exuded more. The wound healing speed of mice in 0 g/L ε-PL+SH group was similar to that of sterile dressing group in the early stage but was faster than that of sterile dressing group in the later stage, with moderate exudation. The wound healing of mice in 5.0 g/L ε-PL+SH group was faster than that in the other two groups, with less exudation. The wound healing rates of mice in 5.0 g/L ε-PL+SH group were (40.6±4.2)%, (64.3±4.1)%, and (95.8±2.4)% on PID 3, 7, and 12, which were significantly higher than (20.4±2.7)%, (38.9±2.2)%, and (59.1±6.2)% in sterile dressing group and (21.6±2.6)%, (44.0±1.7)%, and (82.2±5.3)% in 0 g/L ε-PL+SH group (P<0.01). The wound healing rates of mice in 0 g/L ε-PL+SH group on PID 7 and 12 were significantly higher than those in sterile dressing group (P<0.05 or P<0.01). On PID 12, the wounds of mice in 5.0 g/L ε-PL+SH group were almost completely epithelialized with less inflammatory cell infiltration, the wounds of mice in 0 g/L ε-PL+SH group were partially epithelialized with a large number of inflammatory cell infiltration, and no obvious epithelialization but a large number of inflammatory cell infiltration was found in the wounds of mice in sterile dressing group. Conclusions: The composite MNs prepared by TSPBA, PVA, ε-PL, and SH can successfully penetrate mouse skin and slowly respond to ROS in the wound to resolve and release antibacterial substances, inhibit bacterial colonization, and promote the repair of full-thickness skin defect wounds with bacterial colonization in diabetic mice.


Assuntos
Diabetes Mellitus Experimental , Animais , Antibacterianos/farmacologia , Escherichia coli , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Espécies Reativas de Oxigênio , Staphylococcus aureus
19.
Kyobu Geka ; 74(12): 1020-1023, 2021 Nov.
Artigo em Japonês | MEDLINE | ID: mdl-34795146

RESUMO

We report a rare case of isolated pulmonary valve endocarditis in a 60-year-old man without congenital heart defects. He had a persistent fever and back neck pain after pulling out his teeth. Echo cardiography revealed a mobile vegetation (measuring 53 mm in size) adhering to the pulmonary valve and blood cultures showed the presence of Staphylococcus aureus( S. aureus). Because of mobile vegetation, pulmonic embolism and presence of S. aureus, surgical treatment was selected. During surgical procedure, we found that the vegetation had destroyed markedly pulmonary valve leaflets. After excising pulmonary valve leaflets, we implanted a bioprosthetic valve and enlarged the pulmonary artery with autologous pericardium. A year after surgery, the patient is stable with no sign of infection.


Assuntos
Endocardite Bacteriana , Endocardite , Cardiopatias Congênitas , Valva Pulmonar , Endocardite Bacteriana/complicações , Endocardite Bacteriana/diagnóstico por imagem , Endocardite Bacteriana/cirurgia , Cardiopatias Congênitas/complicações , Cardiopatias Congênitas/diagnóstico por imagem , Cardiopatias Congênitas/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Valva Pulmonar/diagnóstico por imagem , Valva Pulmonar/cirurgia , Staphylococcus aureus
20.
Int J Nanomedicine ; 16: 7249-7268, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34737563

RESUMO

Introduction: With increases in implant infections, the search for antibacterial and biofilm coatings has become a new interest for orthopaedists and dentists. In recent years, graphene oxide (GO) has been extensively studied for its superior antibacterial properties. However, most of these studies have focused on solutions and there are few antibacterial studies on metal surfaces, especially the surfaces of cobalt-chromium-molybdenum (CoCrMo) alloys. ε-Poly-L-lysine (ε-PLL), as a novel food preservative, has a spectrum of antimicrobial activity; however, its antimicrobial activity after coating an implant surface is not clear. Methods: In this study, for the first time, a two-step electrodeposition method was used to coat GO and ε-PLL on the surface of a CoCrMo alloy. Its antibacterial and antibiofilm properties against S. aureus and E. coli were then studied. Results: The results show that the formation of bacteria and biofilms on the coating surface was significantly inhibited, GO and ε-PLL composite coatings had the best antibacterial and antibiofilm effects, followed by ε-PLL and GO coatings. In terms of classification, the coatings are anti-adhesive and contact-killing/inhibitory surfaces. In addition to oxidative stress, physical damage to GO and electrostatic osmosis of ε-PLL are the main antibacterial and antibiofilm mechanisms. Discussion: This is the first study that GO and ε-PLL coatings were successfully prepared on the surface of CoCrMo alloy by electrodeposition. It provides a promising new approach to the problem of implant infection in orthopedics and stomatology.


Assuntos
Polilisina , Staphylococcus aureus , Antibacterianos/farmacologia , Biofilmes , Materiais Revestidos Biocompatíveis/farmacologia , Escherichia coli , Grafite , Polilisina/farmacologia , Propriedades de Superfície , Vitálio
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