scholarly journals Pseudomonas aeruginosa as a Potential Contaminant of Packed Fresh-Cut Lettuce in a Controlled Atmosphere. The Role of Phenotypes muc+/muc–

2020 ◽  
Vol 11 (2) ◽  
pp. 8716-8724
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Real Time ◽  
Foodborne Pathogens ◽  
Rrna Gene ◽  
Modified Atmosphere ◽  
Fresh Cut ◽  
Time Specific ◽  
Sanitation Systems ◽  
Biofilm Development

In order to shed light on contamination risks along the ready-to-eat chain of fresh commodities by emerging foodborne pathogens, we investigated the biofilm development in vitro of two Pseudomonas aeruginosa strains on fresh-cut lettuce (Lactuca sativa L. var. Iceberg). The experiment was performed employing a floating bioreactor system where modified atmosphere package conditions were mimicked, and fresh-cut lettuce disks of 2 cm2 were put into contact with a 106 CFU/mL of a phenotypic mucoid P. aeruginosa phenotype (muc+) or a non-mucoid one (muc-). Following a simulated 2-day refrigerated-shelf quantitative Real-Time PCR, designed on a target gene region of the 16S rRNA gene, defined the different muc phenotypes behavior on biofilm in lettuce phyllo-plane. Between the two strains, a development difference of nearly 1.0 log CFU/cm2 occurred, with the muc+ phenotype being the most settled and adherent. This result clearly showed a distinct contamination risk according to P. aeruginosa phenotype and the need to develop real-time, specific, fast, and easy to use detection protocols along with specific sanitation systems for modified atmosphere package ready-to-eat commodities.

scholarly journals Novel Genomic Tools for Specific and Real-Time Detection of Biothreat and Frequently Encountered Foodborne Pathogens

2012 ◽  
Vol 75 (4) ◽  
pp. 660-670 ◽  
Author(s):  
ABDELA WOUBIT ◽  
TESHOME YEHUALAESHET ◽  
TSEGAYE HABTEMARIAM ◽  
TEMESGEN SAMUEL
Keyword(s):  
Real Time ◽  
Foodborne Pathogens ◽  
Yersinia Pseudotuberculosis ◽  
Bacterial Species ◽  
Preliminary Test ◽  
Shigella Dysenteriae ◽  
Whole Genome ◽  
Tularensis Subsp ◽  
Primer Sets

The bacterial genera Escherichia, Salmonella, Shigella, Vibrio, Yersinia, and Francisella include important food safety and biothreat agents. By extensive mining of the whole genome and protein databases of diverse, closely and distantly related bacterial species and strains, we have identified novel genome regions, which we utilized to develop a rapid detection platform for these pathogens. The specific genomic targets we have identified to design the primers in Francisella tularensis subsp. tularensis, F. tularensis subsp. novicida, Shigella dysenteriae, Salmonella enterica serovar Typhimurium, Vibrio cholerae, Yersinia pestis, and Yersinia pseudotuberculosis contained either known genes or putative proteins. Primer sets were designed from the target regions for use in real-time PCR assays to detect specific biothreat pathogens at species or strain levels. The primer sets were first tested by in silico PCR against whole-genome sequences of different species, subspecies, or strains and then by in vitro PCR against genomic DNA preparations from 23 strains representing six biothreat agents (Escherichia coli O157:H7 strain EDL 933, Shigella dysenteriae, S. enterica serovar Typhi, F. tularensis subsp. tularensis, V. cholerae, and Y. pestis) and six foodborne pathogens (Salmonella Typhimurium, Salmonella Saintpaul, Shigella sonnei, F. tularensis subsp. novicida, Vibrio parahaemolyticus, and Y. pseudotuberculosis). Each pathogen was specifically identifiable at the genus and species levels. Sensitivity assays performed with purified DNA showed the lowest detection limit of 128 fg of DNA/μl for F. tularensis subsp. tularensis. A preliminary test to detect Shigella organisms in a milk matrix also enabled the detection of 6 to 60 CFU/ml. These new tools could ultimately be used to develop platforms to simultaneously detect these pathogens.

scholarly journals Biochemical and immunological characterization of haemolysin produced by Pseudomonas aeruginosa PAO1 isolated from burn wounds

2020 ◽  
Vol 21 (2) ◽  
pp. 132-139
Author(s):  
A.A. Allam ◽  
A.M. El-shawadfy ◽  
W.A.E. Hassanein ◽  
E.H.A. Hamza ◽  
E.A. Morad ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Intraperitoneal Injection ◽  
Neutralization Test ◽  
Multidrug Resistant ◽  
Maximum Activity ◽  
Resistant Organism ◽  
Rrna Gene ◽  
Isolation And Identification ◽  
Burn Wounds

Background: Infection of burn wounds by multidrug-resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa) is a leading cause of morbidity and mortality and remains one of the most challenging concerns for the burns unit. The aim of this study is purify and characterize the haemolysin produced by multidrug resistant P. aeruginosa PAO1 isolated from burn wounds. Methods: Isolation and identification of P. aeruginosa from burns was done by standard bacteriological methods. P. aeruginosa PAO1 was identified by PCR amplification and sequencing of the 16S rRNA gene. The haemolysin of P. aeruginosa PAO1 was purified by 70% ammonium sulphate precipitation followed by gel filtration on Sephadex G-100, and separation by SDS-Poly Acrylamide Gel Electrophoresis. In vivo toxicity of the purified haemolysin was determined by intraperitoneal injection of Swiss albino mice, and in vitro toxin-antitoxin neutralization test was performed as previously described. Results: The pure haemolysin had a molecular weight of 37 kDa, with maximum activity at 25°C for 30 minutes and stable within pH range of 4-9 (maximum activity at pH 7). The haemolysin was activated by Ca2+, Fe3+ and Cu2+. Intraperitoneal injection of mice with 0.5ml of haemolysin (128 HU/ml) caused 100% mortality while 0.5 and 0.1 ml of haemolytic titer (64 HU/ml) of the heated haemolysin (toxoid) caused 50% and 0% mortality respectively. In vitro toxin-antitoxin neutralization test revealed that anti-haemolysin antitoxin was present in the serum of the mice that were previously vaccinated with heated toxin. Conclusion: This study concluded that haemolysin can be a potential vaccine component for prevention of haemolysis caused by multidrug resistant P. aeruginosa in burn patients.Keywords: haemolysin, Pseudomonas aeruginosa, multidrug resistant organism

scholarly journals Real-time monitoring of Pseudomonas aeruginosa biofilm formation on endotracheal tubes in vitro

2018 ◽  
Vol 18 (1) ◽  
Author(s):  
Eva Pericolini ◽  
Bruna Colombari ◽  
Gianmarco Ferretti ◽  
Ramona Iseppi ◽  
Andrea Ardizzoni ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Real Time ◽  
Biofilm Formation ◽  
Real Time Monitoring ◽  
Endotracheal Tubes

scholarly journals Differential Efficacy of Two Dental Implant Decontamination Techniques in Reducing Microbial Biofilm and Re-Growth onto Titanium Disks In Vitro

2019 ◽  
Vol 9 (15) ◽  
pp. 3191 ◽  
Author(s):  
Aida Meto ◽  
Enrico Conserva ◽  
Francesco Liccardi ◽  
Bruna Colombari ◽  
Ugo Consolo ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Real Time ◽  
Dental Implant ◽  
Clinical Implication ◽  
Nickel Titanium ◽  
Microbial Load ◽  
Clinical Progression ◽  
Missing Teeth ◽  
Biofilm Removal

Dental implants are crucial therapeutic devices for successful substitution of missing teeth. Failure cases are mainly pathogen-associated events, allowing clinical progression toward peri-mucositis or peri-implantitis. The aim of this study was to compare the performance of two mechanical decontamination systems, Nickel-Titanium brush (Brush) and Air-Polishing system with 40 µm bicarbonate powder (BIC-40), by means of a novel bioluminescence-based model that measures microbial load in real time. Briefly, 30 disks were contaminated using the bioluminescent Pseudomonas aeruginosa strain (BLI-P. aeruginosa), treated with Brush (30 s rounds, for 90 s) or BIC-40 (30 s, at 5 mm distance) procedure, and then assessed for microbial load, particularly, biofilm removal and re-growth. Our results showed that Brush and BIC-40 treatment reduced microbial load of about 1 and more than 3 logs, respectively. Furthermore, microbial re-growth onto Brush-treated disks rapidly occurred, while BIC-40-treated disks were slowly recolonized, reaching levels of microbial load consistently below those observed with the controls. In conclusion, we provide evidence on the good performance of BIC-40 as titanium device-decontamination system, the clinical implication for such findings will be discussed.

Sputum neutrophil elastase associates with microbiota and Pseudomonas aeruginosa in bronchiectasis

2020 ◽  
Vol 56 (4) ◽  
pp. 2000769 ◽  
Author(s):  
Martina Oriano ◽  
Andrea Gramegna ◽  
Leonardo Terranova ◽  
Giovanni Sotgiu ◽  
Imran Sulaiman ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Real Time ◽  
Shannon Entropy ◽  
Real Time Pcr ◽  
Neutrophil Elastase ◽  
Stable State ◽  
Rrna Gene ◽  
Respiratory Pathogens ◽  
Α Diversity ◽  
Significant Difference

IntroductionNeutrophilic inflammation is a major driver of bronchiectasis pathophysiology, and neutrophil elastase activity is the most promising biomarker evaluated in sputum to date. How active neutrophil elastase correlates with the lung microbiome in bronchiectasis is still unexplored. We aimed to understand whether active neutrophil elastase is associated with low microbial diversity and distinct microbiome characteristics.MethodsAn observational, cross-sectional study was conducted at the bronchiectasis programme of the Policlinico Hospital in Milan, Italy, where adults with bronchiectasis were enrolled between March 2017 and March 2019. Active neutrophil elastase was measured on sputum collected during stable state, microbiota analysed through 16S rRNA gene sequencing, molecular assessment of respiratory pathogens carried out through real-time PCR and clinical data collected.ResultsAmong 185 patients enrolled, decreasing α-diversity, evaluated through the Shannon entropy (ρ −0.37, p<0.00001) and Pielou's evenness (ρ −0.36, p<0.00001) and richness (ρ −0.33, p<0.00001), was significantly correlated with increasing elastase. A significant difference in median levels of Shannon entropy as detected between patients with neutrophil elastase ≥20 µg·mL−1 (median 3.82, interquartile range 2.20–4.96) versus neutrophil elastase <20 µg·mL−1 (4.88, 3.68–5.80; p<0.0001). A distinct microbiome was found in these two groups, mainly characterised by enrichment with Pseudomonas in the high-elastase group and with Streptococcus in the low-elastase group. Further confirmation of the association of Pseudomonas aeruginosa with elevated active neutrophil elastase was found based on standard culture and targeted real-time PCR.ConclusionsHigh levels of active neutrophil elastase are associated to low microbiome diversity and specifically to P. aeruginosa infection.

scholarly journals Antibiotic Sensitivity and Evaluation of Plasmid Profile of Major Foodborne Pathogens

2016 ◽  
Vol 06 (04) ◽  
pp. 04-09 ◽  
Author(s):  
Ibikunle Ibitayo Anibijuwon ◽  
Ifeoluwa Deborah Gbala ◽  
Jumai Adeola Abioye ◽  
Paul Oluwaseun Ogunlade
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Foodborne Pathogens ◽  
Susceptibility Testing ◽  
Antibiotic Sensitivity ◽  
Plasmid Profile ◽  
Antibiotics Resistance ◽  
Proteus Vulgaris ◽  
Food Borne ◽  
Plasmid Profiling

AbstractThis study revealed the reason behind the antibiotics resistance of isolated food-borne pathogens through their susceptibility testing to various antibiotics of choice. The results of the study revealed that resistance of the bacteria isolates which are Streptococcus sp., Staphylococcus aureus, Proteus vulgaris, Shigella sp., Escherichia coli, Pseudomonas aeruginosa, Bacillus sp. to different antibiotics varies and differs considerably. For instance, Pseudomonas aeruginosa showed resistance to Amoxicillin, Augmentin, Gentamicin and Tetracycline. Staphylococcus sp. isolated showed multiple resistances to Cloxacillin, Erythromycin, Amoxicillin, Augmentin and Gentamicin. Proteus vulgaris showed multiple resistances to five antibiotics in-vitro which are Augmentin, Nitrofurantoin, Amoxicillin, Cotrimoxazole and Nalidixic. The seven isolates were then assayed for plasmid profiling by agarose gel electrophoresis. All the isolates has plasmid with varying sizes of between 9–21kb. Further conjugative study will reveal more reason behind the resistance.

scholarly journals Modulation of Pseudomonas aeruginosa Biofilm Dispersal by a Cyclic-Di-GMP Phosphodiesterase with a Putative Hypoxia-Sensing Domain

2010 ◽  
Vol 76 (24) ◽  
pp. 8160-8173 ◽  
Author(s):  
Shuwen An ◽  
Ji'en Wu ◽  
Lian-Hui Zhang
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Regulatory Protein ◽  
Phosphodiesterase Activity ◽  
Low Oxygen ◽  
Ggdef Domain ◽  
Biofilm Dispersal ◽  
Biofilm Development

ABSTRACT Pseudomonas aeruginosa encodes many enzymes that are potentially associated with the synthesis or degradation of the widely conserved second messenger cyclic-di-GMP (c-di-GMP). In this study, we show that mutation of rbdA, which encodes a fusion protein consisting of PAS-PAC-GGDEF-EAL multidomains, results in decreased biofilm dispersal. RbdA contains a highly conserved GGDEF domain and EAL domain, which are involved in the synthesis and degradation of c-di-GMP, respectively. However, in vivo and in vitro analyses show that the full-length RbdA protein only displays phosphodiesterase activity, causing c-di-GMP degradation. Further analysis reveals that the GGDEF domain of RbdA plays a role in activating the phosphodiesterase activity of the EAL domain in the presence of GTP. Moreover, we show that deletion of the PAS domain or substitution of the key residues implicated in sensing low-oxygen stress abrogates the functionality of RbdA. Subsequent study showed that RbdA is involved in positive regulation of bacterial motility and production of rhamnolipids, which are associated with biofilm dispersal, and in negative regulation of production of exopolysaccharides, which are required for biofilm formation. These data indicate that the c-di-GMP-degrading regulatory protein RbdA promotes biofilm dispersal through its two-pronged effects on biofilm development, i.e., downregulating biofilm formation and upregulating production of the factors associated with biofilm dispersal.

scholarly journals Rhamnose Binding Protein as an Anti-Bacterial Agent—Targeting Biofilm of Pseudomonas aeruginosa

Marine Drugs ◽  
2019 ◽  
Vol 17 (6) ◽  
pp. 355 ◽  
Author(s):  
Tse-Kai Fu ◽  
Sim-Kun Ng ◽  
Yi-En Chen ◽  
Yuan-Chuan Lee ◽  
Fruzsina Demeter ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Lung Epithelial Cells ◽  
Bacterial Agent ◽  
Lung Epithelial ◽  
Biofilm Development

More than 80% of infectious bacteria form biofilm, which is a bacterial cell community surrounded by secreted polysaccharides, proteins and glycolipids. Such bacterial superstructure increases resistance to antimicrobials and host defenses. Thus, to control these biofilm-forming pathogenic bacteria requires antimicrobial agents with novel mechanisms or properties. Pseudomonas aeruginosa, a Gram-negative opportunistic nosocomial pathogen, is a model strain to study biofilm development and correlation between biofilm formation and infection. In this study, a recombinant hemolymph plasma lectin (rHPLOE) cloned from Taiwanese Tachypleus tridentatus was expressed in an Escherichia coli system. This rHPLOE was shown to have the following properties: (1) Binding to P. aeruginosa PA14 biofilm through a unique molecular interaction with rhamnose-containing moieties on bacteria, leading to reduction of extracellular di-rhamnolipid (a biofilm regulator); (2) decreasing downstream quorum sensing factors, and inhibiting biofilm formation; (3) dispersing the mature biofilm of P. aeruginosa PA14 to improve the efficacies of antibiotics; (4) reducing P. aeruginosa PA14 cytotoxicity to human lung epithelial cells in vitro and (5) inhibiting P. aeruginosa PA14 infection of zebrafish embryos in vivo. Taken together, rHPLOE serves as an anti-biofilm agent with a novel mechanism of recognizing rhamnose moieties in lipopolysaccharides, di-rhamnolipid and structural polysaccharides (Psl) in biofilms. Thus rHPLOE links glycan-recognition to novel anti-biofilm strategies against pathogenic bacteria.

scholarly journals Pseudomonas aeruginosa inhibits in-vitro Candida biofilm development.

2010 ◽  
Vol 10 (1) ◽  
pp. 125 ◽  
Author(s):  
H.m.h.n. Bandara ◽  
J.y.y. Yau ◽  
R.m. Watt ◽  
L.j. Jin ◽  
L.p. Samaranayake
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Development ◽  
Candida Biofilm

scholarly journals Pseudomonas aeruginosa associated pulmonary infections and in vitro amplification virulent rhamnolipid (rhlR) gene

2022 ◽  
Vol 82 ◽  
Author(s):  
N. M. Ali ◽  
S. Chatta ◽  
I. Liaqat ◽  
S. A. Mazhar ◽  
B. Mazhar ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Respiratory Infections ◽  
Research Work ◽  
Diffusion Method ◽  
Rrna Gene ◽  
R Gene ◽  
Pulmonary Infections ◽  
Zone Of Inhibition

Abstract Background Pseudomonas aeruginosa is a common opportunistic pathogenic bacterium with the ability to develop a strong communication pathway by quorum sensing system and different virulent factors. Among the various important secretions of P. aeruginosa rhamnolipid is important biological detergent, believed to be involved in the development of the biofilm and intercellular communication. It readily dissolves the lung surfactants that are then easily catalyzed by the phospholipases and in this way is involved in the acute pulmonary infection. Objective research work was designed to investigate virulence and gene associated with virulence in P. aeruginosa responsible for pulmonary infections. Methods In current study polymerase chain reaction (PCR) was used for the detection of the rhlR (rhamnolipid encoding) gene of isolated strains. A number of assays were performed that ensured its virulent behavior. Disc diffusion method was used to check its antibiotic resistance. Isolated strains were resistant to a number of antibiotics applied. Result It was found that males are more prone to respiratory infections as compared to females. Male members with age of 44-58 and 59-73 are at a higher risk, while females with age of 44-58 are also at a risk of pulmonary infections. Antibiotic resistance was observed by measuring zone of inhibition in strains GCU-SG-M4, GCU-SG-M3, GCU-SG-M5, GCU-SG-M2, GCU-SG-M1 and GCU-SG-M6. GCU-SG-M2 was resistant to fluconazole (FLU), clarithromycin (CLR), cefixime (CFM) and Penicillin (P10). No zone of inhibition was observed. But it showed unusual diffused zone around the Ak and MEM antibiotic discs. rhl R gene and 16s rRNA gene were characterized and analyzed. Conclusion Findings from current study would help in raising awareness about antibiotic resistance of P. aeruginosa, and also the sequence of rhl R gene can be used as the diagnostic marker sequence to identify the virulent rhl R gene sequence from the samples when isolated from sputum of Pneumonia patients.

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