Phenotypic heterogeneity of Pseudomonas aeruginosa isolates in the protected nature park ‘Palić’ (Serbia)

2016 ◽  
Vol 16 (5) ◽  
pp. 1370-1377 ◽  
Author(s):  
Bojana Vujović ◽  
Smilja Teodorović ◽  
Željka Rudić ◽  
Mile Božić ◽  
Vera Raičević
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Environmental Conditions ◽  
Biofilm Formation ◽  
Phenotypic Diversity ◽  
Production Capacity ◽  
Wide Distribution ◽  
Clear Correlation ◽  
Protective Mechanism ◽  
Biofilm Production

Pseudomonas aeruginosa is a globally distributed environmental bacterium, which is also a significant opportunistic pathogen of humans, animals and plants. It is considered that wide distribution of this bacterium is connected with its most significant constitutive property to form biofilms, and that this multicellular mode of growth, predominant in nature, serves as a protective mechanism against unfavourable environmental conditions. The work presented here examines the phenotypic diversity of Pseudomonas aeruginosa environmental isolates with respect to biofilm production capacity under different environmental conditions (temperature, pH, NaCl), production of virulence factors, and motility. The purpose of this work is to present the production of two quorum sensing-regulated virulence factors (rhamnolipids and pyocyanin), explore different motility tests (swimming, swarming and twitching) and discover potential relationship between assessed phenotypic features. Obtained results delineate environmental conditions coinciding with biofilm production and suggest a high correlation between rhamnolipid production levels and biofilm formation. Rhamnolipids affect motility competence, yet only the flagellum-mediated swimming motility has significant impact on the biofilm formation potential. Although it is challenging to demarcate a definitive, clear correlation between parameters tested, rhamnolipid content appears to serve as a link between the tested phenotypic factors.

scholarly journals Molecular detection of virulence factors and biofilm formation in Pseudomonas aeruginosa obtained from different clinical specimens in Bandar Abbas

2019 ◽  
Author(s):  
Nima Bahador ◽  
Saeed Shoja ◽  
Foroogh Faridi ◽  
Banafsheh Dozandeh-Mobarrez ◽  
Fatemeh Izadpanah Qeshmi ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Antimicrobial Susceptibility ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Clinical Specimens ◽  
Biofilm Production ◽  
Bandar Abbas ◽  
Susceptibility Patterns

Background and Objectives: Pseudomonas aeruginosa is a ubiquitous opportunistic pathogen. The presence of several virulence factors such as exotoxin and exoenzyme genes and biofilm may contribute to its pathogenicity. The purpose of this study was to investigate the presence of toxA, exoU and exoS, the determination of biofilm production and antimicrobial susceptibility patterns among clinical isolates of P. aeruginosa. Materials and Methods: In this study, 75 isolates of P. aeruginosa were recovered from various clinical specimens. Antimi- crobial susceptibility pattern of isolates were identified. Virulence genes toxA, exoU and exoS were determined using PCR. The ability of biofilm production was assessed. Results: Antimicrobial susceptibility test showed that 12 strains were resistant to more than 8 antibiotics (17.14%). The most effective antibiotic was colistin as 98.6% of isolates were sensitive. The frequencies of exoU and exoS genes were detected as 36.6% and 55.7%, respectively. In addition, 98.6% of the isolates were biofilm producers. Exotoxin A was detected in sixty-eight isolates (95.7%). Conclusion: The findings of this study showed that, the presence of P. aeruginosa exotoxin and exoenzyme genes, particu- larly, the exoU gene is the most common virulence factors in the bacterial isolates from urine samples. Biofilm is a serious challenge in the treatment of P. aeruginosa infection.

Differential surface competition and biofilm invasion strategies of Pseudomonas aeruginosa PA14 and PAO1

2021 ◽  
Author(s):  
Swetha Kassety ◽  
Stefan Katharios-Lanwermeyer ◽  
George A. O’Toole ◽  
Carey D. Nadell
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Matrix Composition ◽  
Model Organisms ◽  
Culture Methods ◽  
Biofilm Growth ◽  
Biofilm Production ◽  
Direct Competition ◽  
Planktonic Phase ◽  
Do So

Pseudomonas aeruginosa strains PA14 and PAO1 are among the two best characterized model organisms used to study the mechanisms of biofilm formation, while also representing two distinct lineages of P. aeruginosa . Previous work has shown that PA14 and PAO1 use different strategies for surface colonization; they also have different extracellular matrix composition and different propensities to disperse from biofilms back into the planktonic phase surrounding them. We expand on this work here by exploring the consequences of these different biofilm production strategies during direct competition. Using differentially labeled strains and microfluidic culture methods, we show that PAO1 can outcompete PA14 in direct competition during early colonization and subsequent biofilm growth, that they can do so in constant and perturbed environments, and that this advantage is specific to biofilm growth and requires production of the Psl polysaccharide. In contrast, the P. aeruginosa PA14 is better able to invade pre-formed biofilms and is more inclined to remain surface-associated under starvation conditions. These data together suggest that while P. aeruginosa PAO1 and PA14 are both able to effectively colonize surfaces, they do so in different ways that are advantageous under different environmental settings. Importance Recent studies indicate that P. aeruginosa PAO1 and PA14 use distinct strategies to initiate biofilm formation. We investigated whether their respective colonization and matrix secretion strategies impact their ability to compete under different biofilm-forming regimes. Our work shows that these different strategies do indeed impact how these strains fair in direct competition: PAO1 dominates during colonization of a naïve surface, while PA14 is more effective in colonizing a pre-formed biofilm. These data suggest that even for very similar microbes there can be distinct strategies to successfully colonize and persist on surfaces during the biofilm life cycle.

scholarly journals Biofilm Formation and Virulence Factors Among Pseudomonas aeruginosa Isolated From Burn Patients

2015 ◽  
Vol 8 (10) ◽  
Author(s):  
Zahra Ghanbarzadeh Corehtash ◽  
Ahmad Khorshidi ◽  
Farzaneh Firoozeh ◽  
Hosein Akbari ◽  
Azam Mahmoudi Aznaveh
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Burn Patients

Isolation and Identification of Fungal Isolates caused Otomycosis from some Hospitals and Clinics in Mosul with Determination of Their Virulence Factors

2021 ◽  
Vol 26 (4) ◽  
Author(s):  
Nabeel Al-Sharrad ◽  
Muhammad A. Al-Kataan ◽  
Maha A. Al-Rejaboo
Keyword(s):  
Fungal Infection ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Fungal Pathogens ◽  
Candida Parapsilosis ◽  
Isolation And Identification ◽  
Fungal Isolates ◽  
Biofilm Production ◽  
Etiological Agents

Otomycosis is a fungal infection that frequently involves the external auditory canal. In this study, we aimed to isolation and identification the fungal isolates as etiological agents of otomycosis from some hospitals and clinics in Mosul with determination of their virulence factors of fungal etiological agents. Positive fungal infection was found in (43) samples (71.6%). The most common fungal pathogens were Candida and Aspergillus species, with Candida parapsilosis being the predominant isolates in (11) samples (16.6%). Otomycosis was more common in Female in (26) samples (43.3%).Otomycosis was the highest prevalence aged group 15-40 years (19) samples (31.3%). The present study of virulence factors revealed that the highest biofilm formation isolates were C. parapsilosis is (10) isolates which were distributed between (2) strong and (8) weak biofilm formation.Where C.trpicales, was recorded as least isolates for biofilm production.

scholarly journals Plantain Herb Extracts significantly attenuate the quorum sensing-controlled virulence factors and inhibit biofilm formation in Pseudomonas aeruginosa PAO1

2019 ◽  
Vol 78 ◽  
pp. 01004
Author(s):  
Shan Li ◽  
Jiangning Yao ◽  
Haoming Li
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Opportunistic Pathogen ◽  
Significant Inhibition ◽  
Control Group ◽  
Produce Cell ◽  
Group B ◽  
Herb Extracts

Pseudomonas aeruginosa is a Gram-negative organism that can survive under harsh conditions, and it is also an opportunistic pathogen that can produce cell-associated extracellular virulence factors. Several of these virulence factors have been demonstrated to be regulated by quorum sensing (QS). Plantain Herb has been used as antibacterial agents for many centuries in China. In this study, we analyzed Plantain Herb Extracts (PHE) at the concentration of 16 μg/mL (Group A, MIC), 8 μg/mL (Group B, 1/2 MIC) and 4 μg/mL (Group C, 1/4 MIC) for inhibition of the virulence factors production and biofilm formation in P. aeruginosa PAO1. The virulence factors included pyocyanin, rhamnolipids, protease and alginate. PHE showed significant inhibition of virulence factors as compared to the control group without interfering its growth. Thus, PHE might be a potent QS inhibitor and anti-biofilm agent in the treatment of Pseudomonas aeruginosa infections.

scholarly journals Biofilm Formation among Clinical and Food Isolates ofListeria monocytogenes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Joana Barbosa ◽  
Sandra Borges ◽  
Ruth Camilo ◽  
Rui Magalhães ◽  
Vânia Ferreira ◽  
...  
Keyword(s):  
Tissue Culture ◽  
Listeria Monocytogenes ◽  
Osmotic Stress ◽  
Environmental Conditions ◽  
Biofilm Formation ◽  
Stress Conditions ◽  
Acidic Stress ◽  
Biofilm Production ◽  
Oflisteria Monocytogenes ◽  
Clinical Cases

Objective. A total of 725Listeria monocytogenesisolates, 607 from various foods and 118 from clinical cases of listeriosis, were investigated concerning their ability to form biofilms, at 4°C during 5 days and at 37°C during 24 h.Methods. Biofilm production was carried out on polystyrene tissue culture plates. FiveL. monocytogenesisolates were tested for biofilm formation after being exposed to acidic and osmotic stress conditions.Results. Significant differences (P<0.01) between clinical and food isolates were observed. At 37°C for 24 h, most food isolates were classified as weak or moderate biofilm formers whereas all the clinical isolates were biofilm producers, although the majority were weak. At 4°C during 5 days, 65 and 59% isolates, from food and clinical cases, respectively, were classified as weak. After both sublethal stresses, at 37°C just one of the five isolates tested was shown to be more sensitive to subsequent acidic exposure. However, at 4°C both stresses did not confer either sensitivity or resistance.Conclusions. Significant differences between isolates origin, temperature, and sublethal acidic stress were observed concerning the ability to form biofilms. Strain, origin, and environmental conditions can determine the level of biofilm production byL. monocytogenesisolates.

scholarly journals Inhibition of Quorum Sensing in Pseudomonas aeruginosa by N-Acyl Cyclopentylamides

2007 ◽  
Vol 73 (10) ◽  
pp. 3183-3188 ◽  
Author(s):  
Takenori Ishida ◽  
Tsukasa Ikeda ◽  
Noboru Takiguchi ◽  
Akio Kuroda ◽  
Hisao Ohtake ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Biofilm Formation ◽  
Homoserine Lactone ◽  
Ring Structure ◽  
Response Regulators ◽  
Maximal Inhibition ◽  
Sensing Systems ◽  
Reporter Assays

ABSTRACT N-Octanoyl cyclopentylamide (C8-CPA) was found to moderately inhibit quorum sensing in Pseudomonas aeruginosa PAO1. To obtain more powerful inhibitors, a series of structural analogs of C8-CPA were synthesized and examined for their ability to inhibit quorum sensing in P. aeruginosa PAO1. The lasB-lacZ and rhlA-lacZ reporter assays revealed that the chain length and the ring structure were critical for C8-CPA analogs to inhibit quorum sensing. N-Decanoyl cyclopentylamide (C10-CPA) was found to be the strongest inhibitor, and its concentrations required for half-maximal inhibition for lasB-lacZ and rhlA-lacZ expression were 80 and 90 μM, respectively. C10-CPA also inhibited production of virulence factors, including elastase, pyocyanin, and rhamnolipid, and biofilm formation without affecting growth of P. aeruginosa PAO1. C10-CPA inhibited induction of both lasI-lacZ by N-(3-oxododecanoyl)-l-homoserine lactone (PAI1) and rhlA-lacZ by N-butanoyl-l-homoserine lactone (PAI2) in the lasI rhlI mutant of P. aeruginosa PAO1, indicating that C10-CPA interferes with the las and rhl quorum-sensing systems via inhibiting interaction between their response regulators (LasR and RhlR) and autoinducers.

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