The prevalence of some Pseudomonas virulence genes related to biofilm formation and alginate production among clinical isolates

2015 ◽  
Vol 13 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Abdolamir Ghadaksaz ◽  
Abbas Ali Imani Fooladi ◽  
Hamideh Mahmoodzadeh Hosseini ◽  
Mohsen Amin
Keyword(s):  
Biofilm Formation ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Alginate Production

scholarly journals Different effects of sub-minimum inhibitory concentrations of gentamicin on the expression of genes involved in alginate production and biofilm formation of Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Fateme Davarzani ◽  
Zahra Yousefpour ◽  
Navid Saidi ◽  
Parviz Owlia
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Virulence Genes ◽  
Microtiter Plate ◽  
Inhibitory Effect ◽  
Clinical Isolates ◽  
Minimum Inhibitory Concentrations ◽  
Alginate Production ◽  
Broth Microdilution Method ◽  
Encoding Genes

Background and Objectives: Antibiotics at sub-minimum inhibitory concentrations (sub-MIC) may alter bacterial viru- lence factors. The objective of this study was to investigate the effect of gentamicin at sub-MIC concentrations on the expres- sion of genes involved in alginate production and biofilm formation of Pseudomonas aeruginosa. Materials and Methods: The broth microdilution method was used to determine the MIC of gentamicin for three P. aeru- ginosa clinical isolates (P1-P3) and standard strains (PAO1 and 8821M). Alginate production and biofilm formation of the bacteria in the presence and absence of sub-MIC concentrations of gentamicin were measured using microtiter plate and carbazole assay, respectively. The real-time PCR method was used to determine the effect of gentamicin at sub-MIC con- centrations on the expression level of genes involved in biofilm formation (pelA and pslA) and alginate production (algD and algU). Results: Gentamicin at sub-MIC concentrations significantly reduced alginate production, biofilm formation, and the expres- sion of alginate and biofilm-encoding genes in clinical isolate P1. This inhibitory effect was also observed on the alginate production of 8821M strain and biofilm formation of PAO1strain. In clinical isolates, P2 and P3, alginate production, biofilm formation, and the expression of alginate and biofilm-encoding genes were significantly increased in exposure to sub-MIC concentrations of gentamicin. Conclusion: This study showed that different phenotypic changes in clinical isolates and standard strains of P. aeruginosa in exposure to sub-MIC concentrations of gentamicin are associated with changes in the expression of virulence genes. Further researches are required to understand the mechanisms involved in regulating the expression of virulence genes after exposure to sub-MIC concentrations of antibiotics.

scholarly journals Evaluation of Antibiotic Resistance Pattern, Alginate and Biofilm Production in Clinical Isolates of Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Fateme DAVARZANI ◽  
Navid SAIDI ◽  
Saeed BESHARATI ◽  
Horieh SADERI ◽  
Iraj RASOOLI ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Bacterial Resistance ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Alginate Production ◽  
Opportunistic Bacteria

Background: Pseudomonas aeruginosa is one of the most common opportunistic bacteria causing nosocomial infections, which has significant resistance to antimicrobial agents. This bacterium is a biofilm and alginate producer. Biofilm increases the bacterial resistance to antibiotics and the immune system. Therefore, the present study was conducted to investigate the biofilm formation, alginate production and antimicrobial resistance patterns in the clinical isolates of P. aeruginosa. Methods: One hundred isolates of P. aeruginosa were collected during the study period (from Dec 2017 to Jul 2018) from different clinical samples of the patients admitted to Milad and Pars Hospitals at Tehran, Iran. Isolates were identified and confirmed by phenotypic and genotypic methods. Antimicrobial susceptibility was specified by the disk diffusion method. Biofilm formation and alginate production were measured by microtiter plate and carbazole assay, respectively. Results: Sixteen isolates were resistant to all the 12 studied antibiotics. Moreover, 31 isolates were MultidrugResistant (MDR). The highest resistance rate was related to ofloxacin (36 isolates) and the least resistance was related to piperacillin-tazobactam (21 isolates). All the isolates could produce the biofilm and alginate. The number of isolates producing strong, medium and weak biofilms was equal to 34, 52, and 14, respectively. Alginate production was more than 400 μg/ml in 39 isolates, 250-400 μg/ml in 51 isolates and less than 250 μg/ml in 10 isolates. Conclusion: High prevalence of MDR, biofilm formation, and alginate production were observed among the clinical isolates of P. aeruginosa. The results also showed a significant relationship between the amount of alginate production and the level of biofilm formation.

scholarly journals The effect of Zinc Oxide Nanoparticles on Pseudomonas Aeruginosa Biofilm Formation and Virulence Genes Expression

2020 ◽  
Author(s):  
wedad abdelraheem ◽  
Ebtisam S. Mohamed
Keyword(s):  
Biofilm Formation ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Public Health Problem ◽  
Microtiter Plate ◽  
Clinical Isolates ◽  
Expression Level ◽  
Microdilution Method ◽  
Genes Expression ◽  
Broth Microdilution Method

Abstract Background: Due to increased resistance to antimicrobial agents, infectious disease remains a public health problem worldwide. Aim: The current study was designed to examine the effect of ZnO nanoparticles (ZnO –np) against the biofilm formation ability of P.aeruginosa clinical isolates and to study its effect on the expression level of the genes involved in biofilm formation and virulence factors production. Methodology: The MIC of ZnO –np against P. aeruginosa was determined by the broth microdilution method. The Effect of ZnO –np on the biofilm-forming isolates of P. aeruginosa was monitored by the microtiter plate method. P.aeruginosa isolates were tested for the expression of different biofilm and virulence genes using real-time rt-PCR. Results: ZnO –np significantly downregulated the expression level of all biofilm and virulence genes of P.aeruginosa clinical isolates except the toxA gene. Conclusions: This study demonstrates the promising use of ZnO –np as an anti-biofilm and anti-virulence compound.

scholarly journals The effect of Zinc Oxide nanoparticles on Pseudomonas aeruginosa biofilm formation and virulence genes expression

2021 ◽  
Vol 15 (06) ◽  
pp. 826-832
Author(s):  
Wedad Mahmoud Abdelraheem ◽  
Ebtisam S Mohamed
Keyword(s):  
Zinc Oxide ◽  
Biofilm Formation ◽  
Zinc Oxide Nanoparticles ◽  
Virulence Genes ◽  
Antimicrobial Agents ◽  
Public Health Problem ◽  
Clinical Isolates ◽  
Expression Level ◽  
Dilution Method ◽  
Oxide Nanoparticles

Introduction: Due to increased resistance to antimicrobial agents, infectious diseases remain a public health problem worldwide. The current study was designed to examine the effect of Zinc Oxide nanoparticles (ZnO–np) against the biofilm formation ability of P. aeruginosa clinical isolates and to study its effect on the expression level of the genes involved in biofilm formation and virulence factors production. Methodology: The MIC of ZnO–np against P. aeruginosa was determined by the broth micro dilution method. The effect of ZnO–np on the biofilm-forming isolates of P. aeruginosa was monitored by the microtiter plate method. P. aeruginosa isolates were tested for the expression of different biofilm and virulence genes using real-time rt-PCR. Results: ZnO–np significantly down-regulated the expression level of all biofilm and virulence genes of P. aeruginosa clinical isolates except the toxA gene. Conclusions: This study demonstrates the promising use of ZnO–np as an anti-biofilm and anti-virulence compound.

scholarly journals Biofilm formation, antimicrobial susceptibility and virulence genes of Uropathogenic Escherichia coli isolated from clinical isolates in Uganda

2020 ◽  
Author(s):  
Paul Katongole ◽  
Fatuma Nalubega ◽  
Najjuka Christine Florence ◽  
Benon Asiimwe ◽  
Irene Andia
Keyword(s):  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Biofilm Formation ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Cross Sectional ◽  
E Coli ◽  
Tract Infections

Abstract Introduction: Uropathogenic E. coli is the leading cause of Urinary tract infections (UTIs), contributing to 80-90% of all community-acquired and 30-50% of all hospital-acquired UTIs. Biofilm forming Uropathogenic E. coli are associated with persistent and chronic inflammation leading to complicated and or recurrent UTIs. Biofilms provide an environment for poor antibiotic penetration and horizontal transfer of virulence genes which favors the development of Multidrug-resistant organisms (MDRO). Understanding biofilm formation and antimicrobial resistance determinants of Uropathogenic E. coli strains will provide insight into the development of treatment options for biofilm-associated UTIs. The aim of this study was to determine the biofilm forming capability, presence of virulence genes and antimicrobial susceptibility pattern of Uropathogenic E. coli isolates in Uganda. Methods: This was a cross-sectional study carried in the Clinical Microbiology and Molecular biology laboratories at the Department of Medical Microbiology, Makerere University College of Health Sciences. We randomly selected 200 Uropathogenic E. coli clinical isolates among the stored isolates collected between January 2018 and December 2018 that had significant bacteriuria (>105 CFU). All isolates were subjected to biofilm detection using the Congo Red Agar method and Antimicrobial susceptibility testing was performed using the Kirby disk diffusion method. The isolates were later subjected PCR for the detection of Urovirulence genes namely; Pap, Fim, Sfa, Afa, Hly and Cnf, using commercially designed primers.Results: In this study, 62.5% (125/200) were positive biofilm formers and 78% (156/200) of these were multi-drug resistant (MDR). The isolates were most resistant to Trimethoprim sulphamethoxazole and Amoxicillin (93%) followed by gentamycin (87%) and the least was imipenem (0.5%). Fim was the most prevalent Urovirulence gene (53.5%) followed by Pap (21%), Sfa (13%), Afa (8%), Cnf (5.5%) and Hyl (0%).Conclusions: We demonstrate a high prevalence of biofilm-forming Uropathogenic E. coli strains that are highly associated with the MDR phenotype. We recommend routine surveillance of antimicrobial resistance and biofilm formation to understand the antibiotics suitable in the management of biofilm-associated UTIs.

scholarly journals Biofilm formation, antimicrobial susceptibility and virulence genes of Uropathogenic Escherichia coli isolated from clinical isolates in Uganda

2019 ◽  
Author(s):  
Paul Katongole ◽  
Fatuma Nalubega ◽  
Najjuka Christine Florence ◽  
Benon Asiimwe ◽  
Irene Andia
Keyword(s):  
Antimicrobial Resistance ◽  
Antimicrobial Susceptibility ◽  
Biofilm Formation ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Cross Sectional ◽  
E Coli ◽  
Tract Infections

Abstract Introduction: Uropathogenic E. coli is the leading cause of Urinary tract infections (UTIs), contributing to 80-90% of all community-acquired and 30-50% of all hospital-acquired UTIs. Biofilm forming Uropathogenic E. coli are associated with persistent and chronic inflammation leading to complicated and or recurrent UTIs. Biofilms provide an environment for poor antibiotic penetration and horizontal transfer of virulence genes which favors the development of Multidrug-resistant organisms (MDRO). Understanding biofilm formation and antimicrobial resistance determinants of Uropathogenic E. coli strains will provide insight into the development of treatment options for biofilm-associated UTIs. The aim of this study was to determine the prevalence of biofilm formation among Uropathogenic E. coli clinical isolates, their relationship with antimicrobial susceptibility patterns, and Urovirulence genes. Methods: This was a cross-sectional study carried in the Clinical Microbiology and Molecular biology laboratories at the Department of Medical Microbiology, Makerere University College of Health Sciences. We randomly selected 200 Uropathogenic E. coli clinical isolates among the stored isolates collected between January 2018 and December 2018 that had significant bacteriuria (>105 CFU). All isolates were subjected to biofilm detection using the Congo Red Agar method and Antimicrobial susceptibility testing was performed using the Kirby disk diffusion method. The isolates were later subjected PCR for the detection of Urovirulence genes namely; Pap, Fim, Sfa, Afa, Hly and Cnf, using commercially designed primers.Results: In this study, 62.5% (125/200) were positive biofilm formers and 78% (156/200) of these were multi-drug resistant(MDR). The isolates were most resistant to Trimethoprim sulphamethoxazole and Amoxicillin (93%) followed by gentamycin (87%) and the least was imipenem (0.5%). Fim was the most prevalent Urovirulence gene (53.5%) followed by Pap (21%), Sfa (13%), Afa (8%), Cnf (5.5%) and Hyl (0%).Conclusions: We demonstrate a high prevalence of biofilm-forming Uropathogenic E. coli strains that are highly associated with the MDR phenotype. We recommend routine surveillance of antimicrobial resistance and biofilm formation to understand the antibiotics suitable in the management of biofilm-associated UTIs.

Antimicrobial resistance and molecular epidemiology of virulence genes among multi-drug resistant clinical isolates in Iran

Gene Reports ◽  
2021 ◽  
pp. 101281
Author(s):  
Mohammadreza Sadr ◽  
Seyed Alireza Fahimzad ◽  
Abdollah Karimi ◽  
Fatemeh Fallah ◽  
Shahnaz Armin ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Molecular Epidemiology ◽  
Virulence Genes ◽  
Clinical Isolates ◽  
Drug Resistant

Detection of Virulence Plasmid–Encoded Genes in Salmonella Typhimurium and Salmonella Kentucky Isolates Recovered from Commercially Processed Chicken Carcasses

2019 ◽  
Vol 82 (8) ◽  
pp. 1364-1368 ◽  
Author(s):  
RIZWANA TASMIN ◽  
PAUL A. GULIG ◽  
SALINA PARVEEN
Keyword(s):  
United States ◽  
Salmonella Typhimurium ◽  
Virulence Genes ◽  
Salmonella Enterica Serovar Typhimurium ◽  
The United States ◽  
Clinical Isolates ◽  
Virulence Plasmid ◽  
Chicken Carcass ◽  
Serovar Typhimurium ◽  
Salmonella Virulence

ABSTRACT Salmonella enterica serovar Typhimurium is one of the leading causes of nontyphoidal gastroenteritis of humans in the United States. Commercially processed poultry carcasses are frequently contaminated with Salmonella serovar Kentucky in the United States. The aim of the study was to detect the Salmonella virulence plasmid containing the spv genes from Salmonella isolates recovered from commercially processed chicken carcasses. A total of 144 Salmonella isolates (Salmonella Typhimurium, n = 72 and Salmonella Kentucky, n = 72) were used for isolation of plasmids and detection of corresponding virulence genes (spvA, spvB, and spvC). Only four (5.5%) Salmonella Typhimurium isolates tested positive for all three virulence genes and hence were classified as possessing the virulence plasmid. All isolates of Salmonella Kentucky were negative for the virulence plasmid and genes. These results indicate that the virulence plasmid, which is very common among clinical isolates of Typhimurium and other Salmonella serovars (e.g., Enteritidis, Dublin, Choleraesuis, Gallinarum, Pullorum, and Abortusovis), may not be present in a significant portion of commercially processed chicken carcass isolates.

DIFFERENCES IN GENOTYPE OF E. FAECALIS AND E. FAECIUM CLINICAL ISOLATES REGARDING CYTOLYSIN AND GELATINASE PRODUCTION IN BULGARIAN PATIENTS

2020 ◽  
Vol 18 (Suppl.1) ◽  
pp. 130-137
Author(s):  
R. Yordanova ◽  
S. Stanilova
Keyword(s):  
Virulence Genes ◽  
Clinical Isolates ◽  
University Hospitals ◽  
Gelatinase Activity ◽  
Non Invasive ◽  
Genotypic Analysis ◽  
Enterococcus Spp ◽  
Virulent Gene ◽  
One Year ◽  
Genotype Correlation

Purpose - compare the phenotype and genotype correlation of cytolysin and gelatinase production in clinical isolates Enterococcus spp. Materials and methods - 100 Enterococcus strains collected over a period of one year from inpatients of two Bulgarian university hospitals, were tested for phenotype production of cytolysin and gelatinase. Multiplex PCR was performed to screen the presence of gelE and cylA virulence genes. Results – 17% of the enterococcal isolates demonstrated only cytolysin production phenotypically. Gelatinase activity was found in 21% of the isolates. Only E. faecalis showed combined phenotypic production of cytolysin plus gelatinase (21%). Forty-five percent of the tested enterococci were identified negative for both hemolysin and gelatinase activity. GelE was the most prevalent virulent gene (48% of the isolates). CylA gene was present alone only in four non-invasive E. faecalis isolates. Twenty-six percent of the isolates possessed both cylA and gelE genes and 21% did not harbor any of the virulence factors genotypically. Conclusion - our results prove that it is appropriate to perform both phenotypic and genotypic analysis of the enterococci virulence profile in parallel in order to better characterize the strains, which in turn may serve to develop more effective methods to limit the spread of infections caused by these microorganisms.

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