scholarly journals Co-existence of LasI, RhI, and Pseudomonas Quinolone Signal Quorum-sensing Genes in Clinical Pseudomonas aeruginosa Isolates

2020 ◽  
Vol 10 (03) ◽  
pp. 337-343
Author(s):  
Anwer J. Faisal ◽  
Munim Radwan Ali ◽  
Layla Abdulhamid Said
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Antibiotics Resistance ◽  
Bacterial Isolates ◽  
Antimicrobial Drugs ◽  
Physiological Processes ◽  
Pseudomonas Quinolone Signal ◽  
Production Pattern

Pseudomonas aeruginosa can regulate different group actives and physiological processes through the quorum sensing mechanism. The aims of this research were to detect the presence of quorum sensing genes in 50 clinical P. aeruginosa isolates, which represent by (lasI, lasR, rhlI, and rhlR) and Pseudomonas quinolone signal (PQS) (PgsA, PgsB, PgsC, PgsD, PgsE, and MvfR) genes by Polymerase chain reaction (PCR) technique and interaction between the two systems. Isolates were subjected to test their susceptibility to 12 antimicrobial drugs, 64% of isolates showed resistance to ceftazidime, followed by carbencillin (56%), while only 8% were resistant to imipenem. In addition, all of the bacterial isolates were distributed within three multidrug-resistant (MDR) patterns, viz., A, B, and C. The highest rate of MDR was showed with MDR pattern C, in which bacterial isolates showed resistance to resist (9→11) antimicrobial drugs. Results revealed that P. aeruginosa isolates have different gene patterns, viz., A to E. According to quorum sensing genes production, pattern A found to express all the genes in LasI, RhI, and PQS system, while pattern B has a defective for the production of lasR, rhlR genes, while the same isolates have the PQS system all present. Significantly, there is a positive relationship between las and rhl system and regulation of antibiotics resistance, in which the bacterial isolates that have las and rhl genes showed high resistance to common antimicrobial agents under study. These findings suggest that PQS can function as an intercellular signal in P. aeruginosa that is not restricted only to alkyl homoserine lactones (AHL).

scholarly journals A Study of Isolation and Identification of Multidrug Resistant Pseudomonas aeruginosa from Wound Specimen

2020 ◽  
pp. 26-31
Author(s):  
Maria Muddassir ◽  
Sadaf Munir ◽  
Almas Raza ◽  
Adeel Iqbal ◽  
Muddassir Ahmed ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Multidrug Resistance ◽  
Antimicrobial Agents ◽  
Morphological Characteristics ◽  
Multidrug Resistant ◽  
Hospitalized Patients ◽  
Clinical Samples ◽  
Isolation And Identification ◽  
Antimicrobial Drugs ◽  
Antibiotic Resistant

Background: Pseudomonas aeruginosa is a clinically important pathogenic microbe in hospitalized patients. It is a major cause of mortality and morbidity having a number of mechanisms that make it antibiotic resistant. Considering the dearth of antimicrobial drugs to treat infection with this pathogen, it has become a necessity to open up new arena for treatment with this organism. Recently, there has been an up rise in the number of multidrug resistant pathogenic strains of Pseudomonas aeruginosa. Objective: Isolation and identification of multidrug resistant Pseudomonas aeruginosa from wound specimens and to evaluate the antibiotic resistant strains of this microbe. Methodology: One hundred and fifty clinical samples of wound were taken from hospitalized patients at Jinnah hospital Lahore during the period of October 2019 to April 2020. In total, twenty (20) isolates of Pseudomonas aeruginosa were identified using the cultural features, morphological characteristics and various biochemical tests plus the Vitek 2 system. Blue/green, brown /blue and yellow/green pigment production showed the presence and growth of Pseudomonas aeruginosa. Results: Percentage of Pseudomonas aeruginosa in females came out to be 15% as compared to 11.42% in males. This was followed by testing susceptibility of isolates of Pseudomonas aeruginosa to various antimicrobial drugs. Piperacillin/tazobactam and meropenem showed the highest efficacy against Pseudomonas aeruginosa. Highest resistance was exhibited against trimethoprim/sulfamethoxazole which was 75%. Conclusion: Most isolates showed multidrug resistance to four or more drugs. Development of multidrug resistance has emerged as a global problem with pathogens commonly causing infections becoming increasingly resistant to antimicrobial agents.

scholarly journals Phenotypic Determination of Biofilm Formation and Acquired Resistance Profile of Clinically-Derived Bacterial Isolates

2020 ◽  
Vol 1 (4) ◽  
Author(s):  
Muhammad M Ibrahim ◽  
Abubakar Shettima ◽  
Ibrahim Y. Ngoshe ◽  
Musa Ibn Abbas ◽  
Hauwa S. Bello ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Pseudomonas Aeruginosa ◽  
Disease Control ◽  
Acquired Resistance ◽  
Multidrug Resistant ◽  
Health Concern ◽  
Bacterial Isolates ◽  
Antimicrobial Drugs ◽  
Resistance Profile ◽  
Diffusion Technique

Infections caused by biofilm forming bacteria is of major public health concern because of its association with multi-resistance to antimicrobial drugs and host defenses, leading to chronic and recurrent infections. Here, using Congo red agar method, Kirby-bauer disk diffusion technique and the consensus criteria of the European Centre for Disease Control (ECDC) and Centre for Disease Control (CDC), we determined the acquired resistance profile of biofilm producing phenotypes of clinically derived bacteria, classified as Multidrug resistant (MDR), extensively drug resistant (XDR) and Pandrug resistant (PDR). Fifty (50) de-identified bacterial isolates, comprising of five different species (Staphylococcus aureus, Escherichia coli, Proteus spp, Klebsiella pneumoniae and Pseudomonas aeruginosa) were sampled for the study. 64.0% of these isolates were observed to produce biofilms. Isolates recovered from urine samples (50.0%) were the most significant biofilm producers, chief among which was Staphylococcus aureus (15.6%) (X2=0.52; p<.05; P=0.9714). 78.0% of the biofilm producing phenotypes were atleast multidrug resistant (31.4% MDR; 31.4% XDR; 15.7% PDR) (f= 0.40678; df=3; p<.05; P=0.7502). Extreme forms of acquired resistance (XDR and PDR) was more pronounced among biofilm producing strains than the non-biofilm producing strains, and was statistically significant (f=5.0; p=.026336; df=14; p<.05). All Staphylococcus aureus and Pseudomonas aeruginosa isolates were atleast multidrug resistant, with the biofilm producing strains of the latter being completely resistant to Gentamicin and Ciprofloxacin. As such, it can be deduced that resistance to multiple antimicrobial drugs is more pronounced among biofilm producing phenotypes of clinically derived bacterial isolates.

scholarly journals Effect of Essential Oils on the Inhibition of Biofilm and Quorum Sensing in Salmonella Enteritidis 13076 and Salmonella Typhimurium 14028

Antibiotics ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1191
Author(s):  
Yuliany Guillín ◽  
Marlon Cáceres ◽  
Rodrigo Torres ◽  
Elena Stashenko ◽  
Claudia Ortiz
Keyword(s):  
Quorum Sensing ◽  
Essential Oils ◽  
Salmonella Enterica ◽  
Salmonella Enteritidis ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Transcriptional Analysis ◽  
Bacterial Cells ◽  
Sem Images ◽  
Biofilm Inhibition

The emergence of multidrug-resistant microorganisms represents a global challenge that has led to a search for new antimicrobial compounds. Essential oils (EOs) from medicinal aromatic plants are a potential alternative for conventional antibiotics. In this study, the antimicrobial and anti-biofilm potential of 15 EOs was evaluated on planktonic and biofilm-associated cells of Salmonella enterica serovar Enteritidis ATCC 13076 (S. enteritidis) and Salmonella enterica serovar Typhimurium ATCC 14028 (S. typhimurium). In total, 4 out of 15 EOs showed antimicrobial activity and 6 EOs showed anti-biofilm activity against both strains. The EO from the Lippia origanoides chemotype thymol-carvacrol II (LTC II) presented the lowest minimum inhibitory concentration (MIC50 = 0.37 mg mL−1) and minimum bactericidal concentration (MBC = 0.75 mg mL−1) values. This EO also presented the highest percentage of biofilm inhibition (>65%) on both microorganisms, which could be confirmed by scanning electron microscopy (SEM) images. Transcriptional analysis showed significant changes in the expression of the genes related to quorum sensing and the formation of the biofilm. EOs could inhibit the expression of genes involved in the quorum sensing mechanism (luxR, luxS, qseB, sdiA) and biofilm formation (csgA, csgB, csgD, flhD, fliZ, and motB), indicating their potential use as anti-biofilm antimicrobial agents. However, further studies are needed to elucidate the action mechanisms of essential oils on the bacterial cells under study.

scholarly journals Evaluation of Moringa Peregrina (Forsk) Fiori, Leaf and Seed Extract Against Multidrug Resistant Strains of Bacteria and Fungus of Clinical Origin

2021 ◽  
Vol 3 (1) ◽  
pp. 20-26
Author(s):  
Suliman Mansour Albalawi ◽  
Abdulrahman K. Al-Asmari ◽  
Syed Rafatullah ◽  
Maysa Mahfoud
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Growth Inhibition ◽  
Acinetobacter Baumannii ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Colorimetric Assay ◽  
Multidrug Resistant ◽  
Klebsiella Pneumonia ◽  
Isolation And Purification ◽  
Moringa Peregrina

  The emergence of antibiotic resistant microorganism strains has become a critical concern in the treatment of infectious diseases and makes the search of an alternative therapy a must. The study was designed to evaluate the in vitro antimicrobial activities of the Moringa peregrina (MP) leave (MPL) and seed (MPS) extracts. Antimicrobial assays were performed using a microplate growth inhibition assay against 11 multidrug-resistant (MDR) strains. Following qualitative analysis, dose-response assays were performed using the MTT colorimetric assay. The results showed a strong correlation between the MPL and MPS extract concentration and growth inhibition (P<0.001). MP extract revealed a remarkable antimicrobial effect and inhibited the growth and survival of MDR pathogens which include Escherichia coli; Pseudomonas aeruginosa; Klebsiella pneumonia; Acinetobacter baumannii; Staphylococcus aureus between (88.6-94.7 %) and between (62.3- 88.7%) against Candida Kefyer; Candida parapsilosis; Candida albicans; Candida glabrata; Aspergillus flavus and Fusarium oxysporum. MIC50 ranging from ≤6.25 to 25 mg/mL. Acinetobacter baumannii and Pseudomonas aeruginosa were the most susceptible to MP extracts (MIC50 < 6.25 mg/mL). These results support the use of MP in Arab traditional medicine as natural antimicrobial agents. Additionally, the use of such naturally occurring adjuvant derived from medicinal plants can be used as an adjuvant with synthetic antibiotics to combat bacterial resistance and to enhance the antibacterial potential. Further studies are recommended on isolation and purification of novel antimicrobial molecules to treat the infections caused by microbes.  

scholarly journals Peptide Mix from Olivancillaria hiatula Interferes with Cell-to-Cell Communication in Pseudomonas aeruginosa

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Edward Ntim Gasu ◽  
Hubert Senanu Ahor ◽  
Lawrence Sheringham Borquaye
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Cell Communication ◽  
Microtiter Plate ◽  
Antibiofilm Activity ◽  
Dependent Manner ◽  
Biofilm Inhibition ◽  
Swarming Motility

Bacteria in biofilms are encased in an extracellular polymeric matrix that limits exposure of microbial cells to lethal doses of antimicrobial agents, leading to resistance. In Pseudomonas aeruginosa, biofilm formation is regulated by cell-to-cell communication, called quorum sensing. Quorum sensing facilitates a variety of bacterial physiological functions such as swarming motility and protease, pyoverdine, and pyocyanin productions. Peptide mix from the marine mollusc, Olivancillaria hiatula, has been studied for its antibiofilm activity against Pseudomonas aeruginosa. Microscopy and microtiter plate-based assays were used to evaluate biofilm inhibitory activities. Effect of the peptide mix on quorum sensing-mediated processes was also evaluated. Peptide mix proved to be a good antibiofilm agent, requiring less than 39 μg/mL to inhibit 50% biofilm formation. Micrographs obtained confirmed biofilm inhibition at 1/2 MIC whereas 2.5 mg/mL was required to degrade preformed biofilm. There was a marked attenuation in quorum sensing-mediated phenotypes as well. At 1/2 MIC of peptide, the expression of pyocyanin, pyoverdine, and protease was inhibited by 60%, 72%, and 54%, respectively. Additionally, swarming motility was repressed by peptide in a dose-dependent manner. These results suggest that the peptide mix from Olivancillaria hiatula probably inhibits biofilm formation by interfering with cell-to-cell communication in Pseudomonas aeruginosa.

scholarly journals Expression of the multidrug resistance operon mexA-mexB-oprM in Pseudomonas aeruginosa: mexR encodes a regulator of operon expression.

1996 ◽  
Vol 40 (9) ◽  
pp. 2021-2028 ◽  
Author(s):  
K Poole ◽  
K Tetro ◽  
Q Zhao ◽  
S Neshat ◽  
D E Heinrichs ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Multidrug Resistance ◽  
Gene Product ◽  
Antimicrobial Agents ◽  
Resistant Mutant ◽  
Multidrug Resistant ◽  
Lacz Fusion ◽  
Base Substitution ◽  
Knockout Mutant

The region upstream of the multiple antibiotic resistance efflux operon mexA-mexB-oprM in Pseudomonas aeruginosa was sequenced, and a gene, mexR, was identified. The predicted MexR product contains 147 amino acids with a molecular mass of 16,964 Da, which is consistent with the observed size of the overexpressed mexR gene product. MexR was homologous to MarR, the repressor of MarA-dependent multidrug resistance in Escherichia coli, and other repressors of the MarR family. A mexR knockout mutant showed a twofold increase in expression of both plasmid-borne and chromosomal mexA-reporter gene fusions compared with the MexR+ parent strain, indicating that the mexR gene product negatively regulates expression of the mexA-mexB-oprM operon. Furthermore, the cloned mexR gene product reduced expression of a plasmid-borne mexA-lacZ fusion in E. coli, indicating that MexR represses mexA-mexB-oprM expression directly. Consistent with the increased expression of the efflux operon in the mexR mutant, the mutant showed an increase (relative to its MexR+ parent) in resistance to several antimicrobial agents. Expression of a mexR-lacZ fusion increased threefold in a mexR knockout mutant, indicating that mexR is negatively autoregulated. OCR1, a nalB multidrug-resistant mutant which overproduces OprM, exhibited a greater than sevenfold increase in expression of a chromosomal mexA-phoA fusion compared with its parent. Introduction of a mexR knockout mutation in strain OCR1 eliminated this increase in efflux gene expression and, as expected, increased the susceptibility of the strain to a variety of antibiotics. The nucleotide sequences of the mexR genes of OCR1 and its parental strain revealed a single base substitution in the former which would cause a predicted substitution of Trp for Arg at position 69 of its mexR product. These data suggest that MexR possesses both repressor and activator function in vivo, the activator form being favored in nalB multidrug-resistant strains.

scholarly journals Problematic clinical isolates of Pseudomonas aeruginosa from the university hospitals in Sofia, Bulgaria: current status of antimicrobial resistance and prevailing resistance mechanisms

2007 ◽  
Vol 56 (7) ◽  
pp. 956-963 ◽  
Author(s):  
Tanya Strateva ◽  
Vessela Ouzounova-Raykova ◽  
Boyka Markova ◽  
Albena Todorova ◽  
Yulia Marteva-Proevska ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Current Status ◽  
University Hospitals ◽  
Active Efflux ◽  
Genes Encoding

A total of 203 clinical isolates of Pseudomonas aeruginosa was collected during 2001–2006 from five university hospitals in Sofia, Bulgaria, to assess the current levels of antimicrobial susceptibility and to evaluate resistance mechanisms to antipseudomonal antimicrobial agents. The antibiotic resistance rates against the following antimicrobials were: carbenicillin 93.1 %, azlocillin 91.6 %, piperacillin 86.2 %, piperacillin/tazobactam 56.8 %, ceftazidime 45.8 %, cefepime 48.9 %, cefpirome 58.2 %, aztreonam 49.8 %, imipenem 42.3 %, meropenem 45.5 %, amikacin 59.1 %, gentamicin 79.7 %, tobramycin 89.6 %, netilmicin 69.6 % and ciprofloxacin 80.3 %. A total of 101 of the studied P. aeruginosa isolates (49.8 %) were multidrug resistant. Structural genes encoding class A and class D β-lactamases showed the following frequencies: bla VEB-1 33.1 %, bla PSE-1 22.5 %, bla PER-1 0 %, bla OXA-groupI 41.3 % and bla OXA-groupII 8.8 %. IMP- and VIM-type carbapenemases were not detected. In conclusion, the studied clinical strains of P. aeruginosa were problematic nosocomial pathogens. VEB-1 extended-spectrum β-lactamases appear to have a significant presence among clinical P. aeruginosa isolates from Sofia. Carbapenem resistance was related to non-enzymic mechanisms such as a deficiency of OprD proteins and active efflux.

scholarly journals Candida albicans-produced farnesol stimulates Pseudomonas quinolone signal production in LasR-defective Pseudomonas aeruginosa strains

Microbiology ◽  
2010 ◽  
Vol 156 (10) ◽  
pp. 3096-3107 ◽  
Author(s):  
Carla Cugini ◽  
Diana K. Morales ◽  
Deborah A. Hogan
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Candida Albicans ◽  
Quorum Sensing ◽  
Homoserine Lactone ◽  
Pseudomonas Quinolone Signal ◽  
Virulence Potential ◽  
Signalling Molecule ◽  
Signal Production ◽  
Phenazine Production ◽  
Insight Into

Candida albicans has been previously shown to stimulate the production of Pseudomonas aeruginosa phenazine toxins in dual-species colony biofilms. Here, we report that P. aeruginosa lasR mutants, which lack the master quorum sensing system regulator, regain the ability to produce quorum-sensing-regulated phenazines when cultured with C. albicans. Farnesol, a signalling molecule produced by C. albicans, was sufficient to stimulate phenazine production in LasR− laboratory strains and clinical isolates. P. aeruginosa ΔlasR mutants are defective in production of the Pseudomonas quinolone signal (PQS) due to their inability to properly induce pqsH, which encodes the enzyme necessary for the last step in PQS biosynthesis. We show that expression of pqsH in a ΔlasR strain was sufficient to restore PQS production, and that farnesol restored pqsH expression in ΔlasR mutants. The farnesol-mediated increase in pqsH required RhlR, a transcriptional regulator downstream of LasR, and farnesol led to higher levels of N-butyryl-homoserine lactone, the small molecule activator of RhlR. Farnesol promotes the production of reactive oxygen species (ROS) in a variety of species. Because the antioxidant N-acetylcysteine suppressed farnesol-induced RhlR activity in LasR− strains, and hydrogen peroxide was sufficient to restore PQS production in las mutants, we propose that ROS are responsible for the activation of downstream portions of this quorum sensing pathway. LasR mutants frequently arise in the lungs of patients chronically infected with P. aeruginosa. The finding that C. albicans, farnesol or ROS stimulate virulence factor production in lasR strains provides new insight into the virulence potential of these strains.

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