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1.
Anal Chim Acta ; 1189: 339223, 2022 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-34815054

RESUMO

The rapid detection of the pathogenic bacteria in patient samples is crucial to expedient patient care. The proposed approach reports the development of a novel lab-on-a-chip device for the rapid detection of P. aeruginosa based on immunomagnetic separation, optical scattering, and machine learning. The immunomagnetic particles with a diameter of 5 µm were synthesized for isolating P. aeruginosa from the test sample. A microfluidic chip was fabricated, and three optical fibers were embedded for connecting a laser light and two photodetectors. The laser light was pointed towards the channel to pass light through the sample. A pair of photodetectors via optical fibers were arranged symmetrically at 45° to the channel. The photodetectors acquired scattered light from the flowing sample and converted the light to an electrical signal. The sample containing immunomagnetic beads linked with bacteria was injected into the microfluidic chip. The optimized conditions for performing the experiments were characterized for real-time detection of P. aeruginosa. The data acquisition system recorded the real-time light scattering from the test sample. After removing noise from the output waveform, five different time-domain statistical features were extracted from each waveform: standard mean, standard variance, skewness, kurtosis, and coefficient of variation. The pathogens classification was performed by training the discrimination model using extracted features based on machine learning algorithms. The support vector machines (SVM) with a sigmoid function kernel showed superior classification performance with 97.9% accuracy among other classifiers, including k-nearest neighbors (KNN), logistic regression (LR), and naïve Bayes (NB). The method can detect P. aeruginosa specifically and quantitatively with a limit of detection of 102 CFU/mL. The device can classify P. aeruginosa within 10 min with a total assay time of 25 min. The device was used to test its ability to detect pathogen from the serum and sputum specimens spiked with 105 CFU/mL concentration of P. aeruginosa. The results indicate that light scattering combined with machine learning can be used to detect P. aeruginosa. The proposed technique is anticipated to be helpful as a rapid device for diagnosing P. aeruginosa related infections.


Assuntos
Dispositivos Lab-On-A-Chip , Pseudomonas aeruginosa , Teorema de Bayes , Humanos , Separação Imunomagnética , Aprendizado de Máquina , Máquina de Vetores de Suporte
2.
J Infect Chemother ; 28(1): 91-94, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34518095

RESUMO

Pseudomonas aeruginosa is a Gram-negative bacillus that often causes severe infections during immunosuppression in patients with hematologic malignancies. P. aeruginosa can easily acquire drug resistance, and often develops into multidrug-resistant P. aeruginosa (MDRP). Although many antibiotics are used in combination to treat MDRP infections, colistin and amikacin are less likely to be transferred to the lungs, and inhalation therapy may be used. Herein, we report a Case of pneumonia caused by MDRP after allogeneic hematopoietic stem cell transplantation (HSCT) treated with inhaled colistin and amikacin. This 61-year-old female patient was diagnosed with myelodysplastic syndromes and underwent allogeneic HSCT from an 8/8 HLA-matched unrelated donor after reduced-intensity conditioning. On the day of the stem cell infusion, the patient's sputum culture was found to be positive for MDRP. The patient subsequently developed bacteremia, pneumonia, and lung abscess caused by MDRP, and we administered multidrug antibiotic therapy including colistin and amikacin inhalation therapy. The patient's blood cultures were subsequently turned negative, and the lung abscess disappeared. To our knowledge, this is the first case of MDRP pneumonia after HSCT in which colistin and amikacin inhalation therapy was effective.


Assuntos
Transplante de Células-Tronco Hematopoéticas , Pneumonia , Infecções por Pseudomonas , Amicacina/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Colistina/uso terapêutico , Farmacorresistência Bacteriana Múltipla , Feminino , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Pessoa de Meia-Idade , Pneumonia/tratamento farmacológico , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa , Terapia Respiratória
3.
J Infect Chemother ; 28(1): 87-90, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34535403

RESUMO

We describe a case of a 48 years old male with left sided endocarditis and septic emboli secondary to a Pseudomonas aeruginosa strain that developed resistance to other ß-lactam antibiotics during therapy resulting in prolonged bacteremia. Blood cultures sterilized within 1 day of initiating ceftolozane/tazobactam 3 g every 8 hours in combination with ciprofloxacin. Steady state free ceftolozane plasma Cmax and Cmin concentrations were calculated to be 122.2µg/mL and 24.3µg/mL, respectively. The multidrug-resistant strain harbored chromosomal ß-lactamases OXA-486 and PDC-3, mutations in ampD and dacB predicted to lead to ampC over-expression, and mutations in OprD predicted to decrease outer membrane permeability. Following completion of a 42 day course and aortic valve replacement, the patient was deemed clinically cured without recurrence of infection at follow up 2 years later. To our knowledge, this is the first reported case to measure ceftolozane concentrations during the treatment of endocarditis which supports dose optimization approaches of severe endovascular disease due to multidrug resistant pathogens.


Assuntos
Endocardite , Infecções por Pseudomonas , Antibacterianos/uso terapêutico , Cefalosporinas/uso terapêutico , Endocardite/tratamento farmacológico , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Ácido Penicilânico , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/genética , Tazobactam/uso terapêutico
4.
Chemosphere ; 287(Pt 1): 132093, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34526274

RESUMO

The effects of chlorine dosage, reaction time, algae concentration, and cell components, including extracellular organic matter (EOM), intracellular organic matter (IOM) and cell debris (CD), were evaluated on the formation of nitrosamines (NAs), including N-Nitrosodimethylamine (NDMA), -Nitrosomethylethylamine (NMEA), N-Nitrosodi-n-propylamine (NDPA), N-nitrosodi-n-butylamine (NDBA), N-Nitrosopyrollidine (NPyr), during the chlorination of Microcystis aeruginosa (M. aeruginosa) and Cyclotella meneghiniana (C. meneghiniana) in drinking water treatment. In addition, the NAs formation from Chlorophyll-a and Microcystin-LR (MC-LR) chlorination was investigated. The results showed that NDMA was the most dominant product of two algae, while only a small yield of NPyr, NMEA and NDBA was generated with NDPA as the least. The nitrosamines formation potential (NAsFP) of M. aeruginosa was positively correlated with the chlorine concentration, while the highest NAsFP of C. meneghiniana was observed at 10 mg/L chlorine. With the increase of reaction time, the NAsFP from C. meneghiniana was higher than M. aeruginosa. The NAs formation enhanced with the increase of cell concentration. Moreover, the impacts of cellular components on the NAsFP followed the order of CD > IOM > EOM and IOM > EOM > CD for M. aeruginosa and C. meneghiniana, respectively. The results indicated that proteins and soluble microbial products (SMPs) were the main cellular components to contribute to NAs formation and IOM was the primary source of NAs precursor for both algae. Chlorination of Chlorophyll-a and MC-LR showed that chlorophyll-a formed only a small yield of NDMA and NDBA, while MC-LR made a more significant contribution to the types of NAs.


Assuntos
Água Potável , Nitrosaminas , Purificação da Água , Halogenação , Nitrosaminas/análise , Pseudomonas aeruginosa
5.
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
6.
Appl Microbiol Biotechnol ; 105(23): 8647-8661, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34750645

RESUMO

Quorum sensing mediated biofilm formation has a major role in modern therapeutics due to adherence of cells on the solid surface. Here, we have developed a stable polyurethane blend with a 6-methylcoumarin (6-MC) composite that showed significant antibiofilm activity. The 6-MC was found to prominently inhibit P. aeruginosa PAO1 biofilm formation at 125 µg/ml and was able to inhibit various virulence factors such as pyocyanin, siderophore, exopolysaccharide, elastase and proteases, including motility of the bacteria. In addition, 6-MC was found functionally active in saving the C. elegans from P. aeruginosa PAO1 infection. Moreover, docking studies of different activator proteins correlate well with in vitro and in vivo results. To enhance this biological activity, 6-MC was blended with polyurethane, which also revealed superior antibiofilm activity on plastic and glass surfaces compared to a polyurethane coating. Therefore, the 6-MC could be used to combat P. aeruginosa infection for effective treatment and antibiofilm applications on solid surfaces through polyurethane blending and subsequent film fabrication strategies. KEY POINTS: • 6-Methylcoumarin significantly inhibits P. aeruginosa PAO1 biofilm • 6-MC was found functionally active in saving the C. elegans from PAO1 infection • 6-MC and polyurethane blend showed superior antibiofilm activity.


Assuntos
Pseudomonas aeruginosa , Percepção de Quorum , Animais , Antibacterianos/farmacologia , Biofilmes , Caenorhabditis elegans , Cumarínicos , Poliuretanos , Fatores de Virulência
7.
Front Cell Infect Microbiol ; 11: 734296, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34746024

RESUMO

Pseudomonas aeruginosa and Aspergillus fumigatus infections frequently co-localize in lungs of immunocompromised patients and individuals with cystic fibrosis (CF). The antifungal activity of P. aeruginosa has been described for its filtrates. Pyoverdine and pyocyanin are the principal antifungal P. aeruginosa molecules active against A. fumigatus biofilm metabolism present in iron-limited or iron-replete planktonic P. aeruginosa culture filtrates, respectively. Using various P. aeruginosa laboratory wild-type strains (PA14, PAO1, PAK), we found antifungal activity against Aspergillus colonies on agar. Comparing 36 PA14 and 7 PAO1 mutants, we found that mutants lacking both major siderophores, pyoverdine and pyochelin, display higher antifungal activity on agar than their wild types, while quorum sensing mutants lost antifungal activity. Addition of ferric iron, but not calcium or magnesium, reduced the antifungal effects of P. aeruginosa on agar, whereas iron-poor agar enhanced antifungal effects. Antifungal activity on agar was mediated by PQS and HHQ, via MvfR. Among the MvfR downstream factors, rhamnolipids and elastase were produced in larger quantities by pyoverdine-pyochelin double mutants and showed antifungal activity on agar. In summary, antifungal factors produced by P. aeruginosa on agar differ from those produced by bacteria grown in liquid cultures, are dependent on quorum sensing, and are downregulated by the availability of ferric iron. Rhamnolipids and elastase seem to be major mediators of Pseudomonas' antifungal activity on a solid surface.


Assuntos
Infecções por Pseudomonas , Pseudomonas , Aspergillus , Biofilmes , Humanos , Pseudomonas aeruginosa , Piocianina , Percepção de Quorum
8.
Front Cell Infect Microbiol ; 11: 756782, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34790589

RESUMO

Objectives: Recently, KPC-producing P. aeruginosa has rapidly emerged and expanded in East China. Here we described the clinical impact and characteristics of bloodstream infections (BSIs) from the dominant KPC-producing CRPA belonging to Sequence Type (ST) 463. Methods: Retrospective cohort study was performed with CRPA BSI cases from 2019 to 2020 in a hospital in East China. Clinical characteristics, risk factors, and all-course mortality were evaluated. All CRPA isolates had whole-genome sequencing, antimicrobial susceptibility testing, and serum resistance assay. Representative isolates were tested for virulence in a Galleria mellonella infection model. Results: Among the 50 CRPA BSI cases, ST463 predominated (48.0%). In multivariate analysis, we found three independent risk factors for fatal outcome: KPC carriage (OR 4.8; CI95% 1.0-23.7; P = 0.05), Pitt bacteremia score (OR 1.3; CI95% 1.0-1.6; P = 0.02), and underlying hematological disease (OR 8.5; CI95% 1.6-46.4; P = 0.01). The baseline clinical variables were not statistically different across STs, however the 28-day mortality was significantly higher in ST463 cases than that in non-ST463 cases (66.7% vs 33.3%, P = 0.03). ExoU and exoS virulence genes coexisted in all ST463 isolates, and the carbapenem resistant gene bla KPC were produced in almost all ST463 isolates, significantly higher than in the non-ST463 group(95.8% vs 7.7%, P<0.001). ST463 CRPA isolates also showed higher resistance rates to antipseudomonal cephalosporins, monobactam, and fluoroquinolones. And ST463 CRPA was confirmed hypervirulence in the larvae model. The genome of one ST463 CRPA strain showed that the bla KPC-2 gene was the sole resistance gene located on a 41,104bp plasmid pZYPA01, carried on a 7-kb composite transposon-like element flanked by two IS26 elements (IS26-Tn3-tnpA-ISKpn27-bla KPC-2-ISKpn6-IS26). Plasmid from various species presented core bla KPC-2 was franked by mobile genetic element ISKpn27 and ISKpn6. Conclusions: In the ST463 CRPA BSI cohort, the mortality rates were higher than those in the non-ST463 CRPA BSI. The ST463 CRPA clone coharboring the bla KPC and exoU/exoS genes emerged and spread in East China, which might develop to a new threat in the clinic. Our results suggest that the surveillance of the new high-risk clone, ST463 CRPA, should be strengthened in China, even worldwide in the future.


Assuntos
Klebsiella pneumoniae , Sepse , Antibacterianos/farmacologia , Proteínas de Bactérias , Humanos , Klebsiella pneumoniae/genética , Pseudomonas aeruginosa/genética , Estudos Retrospectivos , beta-Lactamases
9.
Health Technol Assess ; 25(65): 1-128, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34806975

RESUMO

BACKGROUND: People with cystic fibrosis are susceptible to pulmonary infection with Pseudomonas aeruginosa. This may become chronic and lead to increased mortality and morbidity. If treatment is commenced promptly, infection may be eradicated through prolonged antibiotic treatment. OBJECTIVE: To compare the clinical effectiveness, cost-effectiveness and safety of two eradication regimens. DESIGN: This was a Phase IV, multicentre, parallel-group, randomised controlled trial. SETTING: Seventy UK and two Italian cystic fibrosis centres. PARTICIPANTS: Participants were individuals with cystic fibrosis aged > 28 days old who had never had a P. aeruginosa infection or who had been infection free for 1 year. INTERVENTIONS: Fourteen days of intravenous ceftazidime and tobramycin or 3 months of oral ciprofloxacin. Inhaled colistimethate sodium was included in both regimens over 3 months. Consenting patients were randomly allocated to either treatment arm in a 1 : 1 ratio using simple block randomisation with random variable block length. MAIN OUTCOME MEASURES: The primary outcome was eradication of P. aeruginosa at 3 months and remaining free of infection to 15 months. Secondary outcomes included time to reoccurrence, spirometry, anthropometrics, pulmonary exacerbations and hospitalisations. Primary analysis used intention to treat (powered for superiority). Safety analysis included patients who had received at least one dose of any of the study drugs. Cost-effectiveness analysis explored the cost per successful eradication and the cost per quality-adjusted life-year. RESULTS: Between 5 October 2010 and 27 January 2017, 286 patients were randomised: 137 patients to intravenous antibiotics and 149 patients to oral antibiotics. The numbers of participants achieving the primary outcome were 55 out of 125 (44%) in the intravenous group and 68 out of 130 (52%) in the oral group. Participants randomised to the intravenous group were less likely to achieve the primary outcome; although the difference between groups was not statistically significant, the clinically important difference that the trial aimed to detect was not contained within the confidence interval (relative risk 0.84, 95% confidence interval 0.65 to 1.09; p = 0.184). Significantly fewer patients in the intravenous group (40/129, 31%) than in the oral group (61/136, 44.9%) were hospitalised in the 12 months following eradication treatment (relative risk 0.69, 95% confidence interval 0.5 to 0.95; p = 0.02). There were no clinically important differences in other secondary outcomes. There were 32 serious adverse events in 24 participants [intravenous: 10/126 (7.9%); oral: 14/146 (9.6%)]. Oral therapy led to reductions in costs compared with intravenous therapy (-£5938.50, 95% confidence interval -£7190.30 to -£4686.70). Intravenous therapy usually necessitated hospital admission, which accounted for a large part of this cost. LIMITATIONS: Only 15 out of the 286 participants recruited were adults - partly because of the smaller number of adult centres participating in the trial. The possibility that the trial participants may be different from the rest of the cystic fibrosis population and may have had a better clinical status, and so be more likely to agree to the uncertainty of trial participation, cannot be ruled out. CONCLUSIONS: Intravenous antibiotics did not achieve sustained eradication of P. aeruginosa in a greater proportion of cystic fibrosis patients. Although there were fewer hospitalisations in the intravenous group during follow-up, this confers no advantage over the oral therapy group, as intravenous eradication frequently requires hospitalisation. These results do not support the use of intravenous antibiotics to eradicate P. aeruginosa in cystic fibrosis. FUTURE WORK: Future research studies should combine long-term follow-up with regimens to reduce reoccurrence after eradication. TRIAL REGISTRATION: Current Controlled Trials ISRCTN02734162 and EudraCT 2009-012575-10. FUNDING: This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 25, No. 65. See the NIHR Journals Library website for further project information.


Assuntos
Fibrose Cística , Infecções por Pseudomonas , Adulto , Antibacterianos/uso terapêutico , Criança , Análise Custo-Benefício , Fibrose Cística/tratamento farmacológico , Humanos , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa , Tobramicina
10.
J Chem Inf Model ; 61(11): 5626-5643, 2021 11 22.
Artigo em Inglês | MEDLINE | ID: mdl-34748335

RESUMO

PlaF is a cytoplasmic membrane-bound phospholipase A1 from Pseudomonas aeruginosa that alters the membrane glycerophospholipid (GPL) composition and fosters the virulence of this human pathogen. PlaF activity is regulated by a dimer-to-monomer transition followed by tilting of the monomer in the membrane. However, how substrates reach the active site and how the characteristics of the active site tunnels determine the activity, specificity, and regioselectivity of PlaF for natural GPL substrates have remained elusive. Here, we combined unbiased and biased all-atom molecular dynamics (MD) simulations and configurational free-energy computations to identify access pathways of GPL substrates to the catalytic center of PlaF. Our results map out a distinct tunnel through which substrates access the catalytic center. PlaF variants with bulky tryptophan residues in this tunnel revealed decreased catalysis rates due to tunnel blockage. The MD simulations suggest that GPLs preferably enter the active site with the sn-1 acyl chain first, which agrees with the experimentally demonstrated PLA1 activity of PlaF. We propose that the acyl chain-length specificity of PlaF is determined by the structural features of the access tunnel, which results in favorable free energy of binding of medium-chain GPLs. The suggested egress route conveys fatty acid (FA) products to the dimerization interface and, thus, contributes to understanding the product feedback regulation of PlaF by FA-triggered dimerization. These findings open up opportunities for developing potential PlaF inhibitors, which may act as antibiotics against P. aeruginosa.


Assuntos
Simulação de Dinâmica Molecular , Pseudomonas aeruginosa , Domínio Catalítico , Dimerização , Humanos , Fosfolipases , Especificidade por Substrato
11.
Wiad Lek ; 74(9 cz 2): 2265-2276, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34824170

RESUMO

OBJECTIVE: The aim of this study is to investigate the role of prodigiosin on P. aeruginosa' s biofilm genes involved in the pathogenicity and persistency of the bacteria. PATIENTS AND METHODS: Materials and methods: Gram negative bacterial isolates were taken from burn and wounds specimen obtained from some of Baghdad hospitals. Forty six isolates were identified as Pseudomonas aeruginosa and four isolates as Serratia marcescens by using biochemical tests and VITEK 2 compact system. Susceptibility test was performed for all P. aeruginosa isolates, the results showed that 100% were resistant to Amikacin and 98% were sensitive to Meropenem. Resistant isolates were tested for biofilm formation; the strong and moderate isolates (17) were detected by PCR for AlgD gene presence. From 17 isolates only two had AlgD gene. All serratia isolates were screened for prodigiosin production, which were extracted from the best producer isolate. Minimal inhibitory concentration was assessed for prodigiosin and ciprofloxacin and synergism between them against the two isolates of P. aeruginosa. RESULTS: Results and conclusions: The results showed that the synergistic effect decreased MIC of both prodigiosin and ciprofloxacin by combination, and reduction of biofilm formation was detected. RNA was extracted from the two selected isolates as control in addition to three treatments. The result of quantitative real time PCR showed down regulation in the AlgD gene expression level under some treatments, while there was no gene expression in most treatments with both sub-MICs treatment.


Assuntos
Prodigiosina , Pseudomonas aeruginosa , Antibacterianos/farmacologia , Ciprofloxacina , Humanos , Testes de Sensibilidade Microbiana , Prodigiosina/farmacologia , Pseudomonas aeruginosa/genética
12.
Zhonghua Liu Xing Bing Xue Za Zhi ; 42(5): 898-902, 2021 May 10.
Artigo em Chinês | MEDLINE | ID: mdl-34814485

RESUMO

Objective: To analyze molecular epidemiological characteristics of drug resistance genes and carbapenem resistance of Pseudomonas aeruginosa (PA) in rural well water. Methods: According to Citation of Natural Mineral Water Inspection (GB 8538-2016), a total of 112 well water samples were tested in Juye county of Shandong province, and PFGE and drug susceptibility test were conducted for the identified PA strains. After PCR identification of carbapenem resistance genes, S1-PFGE and Southern blotting were used to determine the location of drug resistance genes, and combined experiments were used to determine gene transferability. Results: The detection rate of PA in rural well water samples in Juye county of Shandong province was 54.46% (61/112). The 61 strains could be divided into 56 PFGE types. There were 2 strains with 100.00% consistent band types, and there was no obvious predominant band type. The results of drug susceptibility experiments showed that 93.44% (57/61) were multi-drug resistant strains, and there were 2 strains carrying blaVIM-2, both of which were located on the plasmid, and both of them were transferred horizontally with the plasmid. Conclusion: PA carrying carbapenem resistance genes was detected in well water of rural communities in Juye country, and there is the possibility of horizontal transmission of such resistance genes.


Assuntos
Pseudomonas aeruginosa , Água , Carbapenêmicos/farmacologia , Resistência a Medicamentos , Humanos , Testes de Sensibilidade Microbiana , Epidemiologia Molecular , Pseudomonas aeruginosa/genética , População Rural , beta-Lactamases
13.
Ulster Med J ; 90(3): 168-174, 2021 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34815596

RESUMO

Antimicrobial resistance (AMR) has now emerged as a major global public health problem. Certain bacterial pathogens, particularly Gram negative organisms associated with patients with cystic fibrosis (CF), have become resistant to several classes of antibiotics resulting in pan-resistance, which creates a clinical treatment dilemma. This study wished to explore the production of antibacterial extracellular metabolites from plant pathogenic fungi. Fungal Culture Extracts (FCEs) were prepared from 10 fungi (Armillaria gallica, Clitocybe nebularis, Fusarium coeruleum, Fusarium oxysporum, Fusarium poae, Hymenoscyphus fraxineus, Nectria fuckeliana, Phytophthora infestans, Phytophthora ramorum, Postia placenta), which were tested for activity against the CF pathogens, Pseudomonas aeruginosa (PA) (n=8), Burkholderia cenocepacia (n=2) and Stenotrophomonas maltophilia (n=2). In addition, FCE were assessed for their ability to alter antibiotic susceptibility in PA (n=8), with six antipseudomonal antibiotics (ceftazidime, ciprofloxacin, colistin, meropenem, piperacillin/tazobactam, tobramycin). None of the FCEs showed inhibitory activity to the 12 bacterial isolates tested, with the exception of the FCE from Postia placenta, which showed inhibition against all 12 bacteria. An antagonistic interaction was observed, where a statistically significant decrease in mean zone sizes was noted with Armillaria gallica (p=0.03) and Phytophthora infestans (p=0.03) FCEs and their interaction with the fluoroquinolone antibiotic, ciprofloxacin. Given the increase in clinical morbidity and mortality associated with chronic lung infections with Pseudomonas aeruginosa, Burkholderia cenocepacia and Stenotrophomonas maltophilia, coupled with the difficulty in treating such chronic infection due to overwhelming antimicrobial resistance, any novel substance showing inhibition of these organisms merits further investigation as a potential future antimicrobial agent, with potential clinical therapeutic application.


Assuntos
Basidiomycota , Burkholderia cenocepacia , Stenotrophomonas maltophilia , Agaricales , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Armillaria , Ascomicetos , Fungos , Fusarium , Humanos , Hypocreales , Polyporales , Pseudomonas aeruginosa
14.
Wiad Lek ; 74(9 cz 1): 2094-2099, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34725282

RESUMO

OBJECTIVE: The aim: To determine the prevalence rate of Staphylococcus aureus infection among children with Cystic Fibrosis in the Dnieper region, to provide microbiological characteristics of the isolates and to elevate their susceptibility to antimicrobials. PATIENTS AND METHODS: Materials and methods: Sputum, tracheobronchial lavage waters and/ or deep smear from the posterior pharyngeal wall were taken from children with genetically confirmed Cystic Fibrosis. Bacteriological method was the main. The first screening for small colony variants of Staphylococcus aureus was carried out after 48 hours of incubation. The antimicrobials susceptibility testing was determined by disk-diffusion method according to the EUCAST 2019. Microsoft Office Excel 2010 was used for statistical data processing. RESULTS: Results: Twenty one children were enrolled in the survey. The culture of Staphylococcus spp. was obtained from all patients with 40.8% positive for Staphylococcus aureus. Small colony variants appeared with the prevalence rate 21.6% after 48 hours of incubation. The frequency of associations between Staphylococcus aureus with auxotroph phenotype with the presence of Pseudomonas aeruginosa was significantly higher than with wild-type group. The 3d-generation aminoglycosides, the 3d-generation fluoroquinolones, linezolid, rifampicin and tetracyclines showed the best antimicrobial activity, however, resistance to cefoxitin and gentamicin was significantly higher in auxotroph-modified group. CONCLUSION: Conclusions: Infection Staphylococcus aureus is common among children. The appearance of auxotrophs registered after treatment with aminoglycosides and/ or co-trimoxazole and co-infection Pseudomonas aeruginosa. Isolates of Staphylococcus aureus showed good chemotherapeutic sensitivity, but tendency in increasing resistance registered for auxotroph-modified phenotype.


Assuntos
Fibrose Cística , Infecções Estafilocócicas , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Criança , Fibrose Cística/complicações , Fibrose Cística/tratamento farmacológico , Humanos , Pseudomonas aeruginosa , Sistema Respiratório , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/epidemiologia , Staphylococcus aureus
15.
Artigo em Inglês | MEDLINE | ID: mdl-34755816

RESUMO

Surveillance strategies to detect colonization are an important tool to prevent and control the spread of microorganisms in hematopoietic stem cell transplant (HSCT) units. The aim of this study was to evaluate routine surveillance cultures for screening colonization and infection by carbapenem-resistant Enterobacteriaceae (CRE), carbapenem-resistant Pseudomonas aeruginosa (CRPa), and vancomycin-resistant enterococci (VRE). Surveillance cultures were collected (1,323 samples) from 200 patients admitted to an HSCT unit over one year; swabs were taken on admission and then weekly. We compared the positivity of cultures for each site, agent, clinical and epidemiological data according to the colonization status. Infection due to multidrug-resistant organisms (MDROs) occurred in 52 (21.5%) patients, 45 (86.5%) due to blood stream infection; 12 (23%) patients had a positive surveillance culture before the infection. Cultures of 554 (41.8%) samples were performed for CRPa, 413 (31.2%) for VRE and 356 (27%) for CRE. Of these, 179 (13.5%) were positive. Colonization by any MDRO, CRE or CRPa was associated with increased risk of infection (P < 0.05), but not with death. Previous colonization by an MDRO was a significant risk for infection by these pathogens, specially by CRE. Overall, rectal swabs had the highest positivity rate compared with other sites, oropharynx swabs were an option for CRPa, and fecal cultures showed low positivity. Although the impact of the strategy on the mortality of patients undergoing HSCT is not clear, routine VRE surveillance should be questioned with regard to patients undergoing auto-HSCT due to the additional cost and little impact on survival rates.


Assuntos
Infecções por Enterobacteriaceae/epidemiologia , Transplante de Células-Tronco Hematopoéticas , Infecções por Pseudomonas/epidemiologia , Enterobacteriáceas Resistentes a Carbapenêmicos/isolamento & purificação , Farmacorresistência Bacteriana Múltipla , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Humanos , Pseudomonas aeruginosa/isolamento & purificação , Enterococos Resistentes à Vancomicina/isolamento & purificação
16.
Can J Microbiol ; 67(12): 894-901, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34731576

RESUMO

This study investigated the effect of cefepime at sub-minimum inhibitory concentrations (sub-MICs) on in vitro biofilm formation (BF) by clinical isolates of Pseudomonas aeruginosa. The effect of cefepime at sub-MIC levels (½-1/256 MIC) on in vitro BF by six clinical isolates of P. aeruginosa was phenotypically assessed following 24 and 48 h of challenge using the tissue culture plate (TCP) assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was employed to observe the change in expression of three biofilm-related genes, namely, a protease-encoding gene (lasA), fimbrial protein-encoding gene (cupA1), and alginate-encoding gene (algC), in a weak biofilm-producing strain of P. aeruginosa following 24 and 48 h of challenge with sub-MICs of cefepime. The BF morphology in response to cefepime was imaged using scanning electron microscopy (SEM). The TCP assay showed strain-, time-, and concentration-dependent changes in in vitro BF in P. aeruginosa following challenge with sub-MICs of cefepime, with a profound increase in strains with inherently no or weak biofilm-producing ability. RT-PCR revealed time-dependent upregulation in the expression of the investigated genes following challenge with ½ and » MIC levels, as confirmed by SEM. Cefepime at sub-MICs could upregulate the expression of BF-related genes and enhance BF by P. aeruginosa clinical isolates.


Assuntos
Infecções por Pseudomonas , Pseudomonas aeruginosa , Antibacterianos/farmacologia , Biofilmes , Cefepima , Humanos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/genética
17.
F1000Res ; 10: 14, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34540201

RESUMO

Background: Pseudomonas aeruginosa, a multidrug resistant Gram-negative bacterium, produces pyocyanin, a virulence factor associated with antibiotic tolerance. High concentrations of royal jelly have an antibacterial effect, which may have the potential to overcome antibacterial resistance. However, in some cases, antibiotic tolerance can occur due to prolonged stress of low-dose antibacterial agents. This study aimed to investigate the effect of subinhibitory concentrations of royal jelly on bacterial growth and pyocyanin production of P. aeruginosa. Methods: Pseudomonas aeruginosa ATCC ® 10145™ and clinical isolates were cultured  in  BHI media for 18 hours followed by optical density measurements at 600 nm wavelength to determine minimum inhibitory concentration (MIC). After 36 hours of incubation, pyocyanin production was observed by measuring the absorbance at 690 nm. Pyocyanin concentrations were calculated using extinction coefficient 4310 M -1cm -1. Results: Results of the MIC tests of both strains were 25%. The highest production of pyocyanin was observed in the subinhibitory concentration group 6.25%, which gradually decreased along with the decrease of royal jelly concentration. Results of one-way ANOVA tests differed significantly in pyocyanin production of the two strains between the royal jelly groups. Tukey HSD test showed concentrations of 12.5%, 6.25%, and 3.125% significantly increased pyocyanin production of ATCC ® 10145™, and the concentrations of 12.5% and 6.25% significantly increased production of the clinical isolates. Conclusions: This study concluded royal jelly concentrations of 25% or above could inhibit bacterial growth; however, only the concentrations of 12.5% and 6.25% could increase pyocyanin production in P. aeruginosa, both in ATCC ® 10145™ and clinical isolates. In conclusion, it is advisable to determine the appropriate concentration of royal jelly to obtain beneficial virulence inhibiting activity.


Assuntos
Pseudomonas aeruginosa , Piocianina , Biofilmes , Ácidos Graxos
18.
Sheng Wu Gong Cheng Xue Bao ; 37(9): 3253-3267, 2021 Sep 25.
Artigo em Chinês | MEDLINE | ID: mdl-34622633

RESUMO

Members of the ferric uptake regulator (Fur) protein family are bacterial transcriptional repressors that control iron uptake and storage in response to iron availability, thereby playing a crucial role in the maintenance of iron homeostasis. The fur null mutants of Pseudomonas aeruginosa could not be obtained because fur is an essential gene. In this study, We constructed a Fur inducibly expression strain Δfur/attB::PBAD-fur in order to study the effect of fur on the growth, biofilm formation, motilities and oxidative stress response of P. aeruginosa. The results showed that a low level of fur expression retarded the growth of P. aeruginosa at an iron-depleted condition, or under high concentration of iron, or in the presence of H2O2. Fur affected the biofilm formation and the motilities (swimming, twitching, and swarming) of strain PAO1. The production of pyoverdine is regulated by Fur. Interestingly, proteins from Magnetospirillum gryphiswaldense MSR-1, which shares homology with Fur, can partially recover the pyoverdine production of strain Δfur/attB::PBAD-fur. This study provides new clues for the prevention and treatment of P. aeruginosa infections.


Assuntos
Peróxido de Hidrogênio , Pseudomonas aeruginosa , Proteínas de Bactérias/genética , Magnetospirillum , Pseudomonas aeruginosa/genética , Proteínas Repressoras/genética
19.
J Vis Exp ; (175)2021 09 24.
Artigo em Inglês | MEDLINE | ID: mdl-34633367

RESUMO

Pseudomonas aeruginosa is an opportunistic bacterial pathogen that causes infections in the airways of cystic fibrosis (CF) patients. P. aeruginosa is known for its ability to form biofilms that are protected by a matrix of exopolysaccharides. This matrix allows the microorganisms to be more resilient to external factors, including antibiotic treatment. One of the most common methods of biofilm growth for research is in microtiter plates or chambered slides. The advantage of these systems is that they allow for the testing of multiple growth conditions, but their disadvantage is that they produce limited amounts of biofilm for RNA extraction. The purpose of this article is to provide a detailed, step by step protocol on how to extract total RNA from small amounts of biofilm of sufficient quality and quantity for high throughput sequencing. This protocol allows for the study of gene expression within these biofilm systems.


Assuntos
Fibrose Cística , Pseudomonas aeruginosa , Biofilmes , Expressão Gênica , Humanos , Pseudomonas aeruginosa/genética , RNA
20.
Int J Mol Sci ; 22(19)2021 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-34639158

RESUMO

Pseudomonas aeruginosa is a common human pathogen belonging to the ESKAPE group. The multidrug resistance of bacteria is a considerable problem in treating patients and may lead to increased morbidity and mortality rate. The natural resistance in these organisms is caused by the production of specific enzymes and biofilm formation, while acquired resistance is multifactorial. Precise recognition of potential antibiotic resistance on different molecular levels is essential. Metabolomics tools may aid in the observation of the flux of low molecular weight compounds in biochemical pathways yielding additional information about drug-resistant bacteria. In this study, the metabolisms of two P. aeruginosa strains were compared-antibiotic susceptible vs. resistant. Analysis was performed on both intra- and extracellular metabolites. The 1H NMR method was used together with multivariate and univariate data analysis, additionally analysis of the metabolic pathways with the FELLA package was performed. The results revealed the differences in P. aeruginosa metabolism of drug-resistant and drug-susceptible strains and provided direct molecular information about P. aeruginosa response for different types of antibiotics. The most significant differences were found in the turnover of amino acids. This study can be a valuable source of information to complement research on drug resistance in P. aeruginosa.


Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Metaboloma/efeitos dos fármacos , Infecções por Pseudomonas/metabolismo , Pseudomonas aeruginosa/metabolismo , Humanos , Infecções por Pseudomonas/tratamento farmacológico , Infecções por Pseudomonas/microbiologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/isolamento & purificação
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