scholarly journals Virulence factors genes and drug resistance in Pseudomonas aeruginosa strains derived from different forms of community and healthcare associated infections

2018 ◽  
Vol 72 ◽  
pp. 751-759 ◽  
Author(s):  
Monika Pobiega ◽  
Agnieszka Chmielarczyk ◽  
Joanna Kozioł ◽  
Monika Pomorska-Wesolowska ◽  
Grzegorz Ziolkowski ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Virulence Factors ◽  
Simultaneous Detection ◽  
Bloodstream Infections ◽  
Effector Proteins ◽  
Diffusion Method ◽  
Virulence Determinants ◽  
Chronic Infections ◽  
Hospitalised Patients ◽  
Tract Infections

Background: The pathogenesis of Pseudomonas aeruginosa (PA) infection is multifactorial and depends mainly on two types of virulence determinants: virulence factors involved in acute infections and membrane bound factors, and virulence factors involved in chronic infections. The aim of this laboratory-based study was to analyse the resistance and virulence of PA strains isolated from different types of infections in hospitalised and non-hospitalised patients in Southern Poland. Material/Methods: Non-repetitive samples from urinary tract infections (UTI), bloodstream infections (BSI) and pneumonia (PNU) were collected. Isolates were screened for the presence of virulence factors by PCR method. Antimicrobial susceptibility testing was performed using disc diffusion method. Metallo-beta-lactamases (MBLs) were detected using an imipenem-EDTA double-disc synergy test. Results: There were 232 specimens collected: UTI-152, PNU-69, BSI-11. Fifty-one (22%) strains were classified as multidrug resistant (MDR), 23 (10%) as extensively-drug resistant (XDR). MDR/XDR strains were more frequently isolated from pneumonia (OR = 2.28). The prevalence values for the genes of effector proteins were 82.8% for exoS, 89% for exoY, and 24% for exoU. The simultaneous detection of four effector proteins was confirmed in 10.4% of the strains. pilB was more prevalent in isolates from the elderly (p=0.013). lasB occurred more frequently in PNU (p=0.048). Three of the genes were more prevalent in isolates from patients hospitalised in ICU (lasB (p=0.017), aprA (p=0.022), phzS (p=0.039)). Conclusions: Understanding the contribution of selected virulence genes to the outcome of an infection may be important for the therapeutic management of patients infected with PA. Simultaneous detection of virulence factors and antimicrobial resistance might be particularly useful because both are clinically important during an infection.

scholarly journals Activation of the Pseudomonas aeruginosa AlgU Regulon through mucA Mutation Inhibits Cyclic AMP/Vfr Signaling

2010 ◽  
Vol 192 (21) ◽  
pp. 5709-5717 ◽  
Author(s):  
Adriana K. Jones ◽  
Nanette B. Fulcher ◽  
Grant J. Balzer ◽  
Mark L. Urbanowski ◽  
Christopher L. Pritchett ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cyclic Amp ◽  
Virulence Factors ◽  
Sigma Factor ◽  
Respiratory Infections ◽  
Response Regulator ◽  
Selective Advantage ◽  
Virulence Determinants ◽  
Loss Of Function ◽  
Chronic Infections

ABSTRACT Pseudomonas aeruginosa is an opportunistic pathogen that causes acute, invasive infections in immunocompromised individuals and chronic, persistent respiratory infections in individuals with cystic fibrosis (CF). The differential progression of acute or chronic infections involves the production of distinct sets of virulence factors. P. aeruginosa strains isolated from patients with acute respiratory infection are generally nonencapsulated and express a variety of invasive virulence factors, including flagella, the type III secretion system (T3SS), type IV pili (TFP), and multiple secreted toxins and degradative enzymes. Strains isolated from chronically infected CF patients, however, typically lack expression of invasive virulence factors and have a mucoid phenotype due to the production of an alginate capsule. The mucoid phenotype results from loss-of-function mutations in mucA, which encodes an anti-sigma factor that normally prevents alginate synthesis. Here, we report that the cyclic AMP/Vfr-dependent signaling (CVS) pathway is defective in mucA mutants and that the defect occurs at the level of vfr expression. The CVS pathway regulates the expression of multiple invasive virulence factors, including T3SS, exotoxin A, protease IV, and TFP. We further demonstrate that mucA-dependent CVS inhibition involves the alternative sigma factor AlgU (AlgT) and the response regulator AlgR but does not depend on alginate production. Our findings show that a single naturally occurring mutation leads to inverse regulation of virulence factors involved in acute and persistent infections. These results suggest that mucoid conversion and inhibition of invasive virulence determinants may both confer a selective advantage to mucA mutant strains of P. aeruginosa in the CF lung.

scholarly journals Comparison of virulence factors and antibiotic resistance of Pseudomonas aeruginosa strains isolated from patients with and without cystic fibrosis

2017 ◽  
Vol 25 (4) ◽  
pp. 327-334
Author(s):  
Salih Macin ◽  
Meral Akarca ◽  
Burcin Sener ◽  
Yakut Akyon
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Respiratory Tract ◽  
Virulence Factors ◽  
Lower Respiratory Tract ◽  
Resistance Rate ◽  
The Other ◽  
Diffusion Method ◽  
Tract Infections

Abstract Its rising incidence, virulence factors and antibiotic resistance rate makes it difficult to treat Pseudomonas aeruginosa infections. The aim of this study was to compare virulence factors and antibiotic resistance of P. aeruginosa isolates from cystic fibrosis (CF) and other lower respiratory tract infections. Isolates from patients (n=125) were divided into two groups. The isolates in the first group were from CF patients (n=64). And in the other group isolates were from lower respiratory tract samples, from patients that did not have CF (n=61). The antibiotic susceptibility tests were done by using disc diffusion method. As phenotypic tests; DNase, protease, elastase, hemolysis, and motility test were performed. The mucoid form of P. aeruginosa was detected in 29.7% of CF patients’ isolates, whereas in the other group (non-CF) this rate was 9.8% (p=0.011). Motility in the CF patients’ isolates was lower (84.4%) then the other group (96.7%). The presence of DNase was significantly low in CF patients’ isolates when compared to the other group (p=0.009). When the antibiotic resistance was compared; ceftazidime, imipenem and meropenem and piperacillin resistance was found significantly low in CF patients compared to isolates from the other group (p≤0.05). Information about virulence factor patterns and antibiotic resistance of P. aeruginosa isolates from patients with cystic fibrosis and the patients without cystic fibrosis can prevent the unnecessary usage of antibiotics and lead the way to new approaches in treatment.

scholarly journals Epidemic Population Structure of Pseudomonas aeruginosa: Evidence for a Clone That Is Pathogenic to the Eye and That Has a Distinct Combination of Virulence Factors

2001 ◽  
Vol 69 (10) ◽  
pp. 6284-6295 ◽  
Author(s):  
Jeanet A. Lomholt ◽  
Knud Poulsen ◽  
Mogens Kilian
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Population Structure ◽  
Virulence Factors ◽  
Contact Lens ◽  
Alkaline Protease ◽  
Protease Activity ◽  
Polymorphism Analysis ◽  
Enzyme Electrophoresis ◽  
Virulence Determinants ◽  
Tract Infections

ABSTRACT The genetic structure of a population of Pseudomonas aeruginosa, isolated from patients with keratitis, endophthalmitis, and contact lens-associated red eye, contact lens storage cases, urine, ear, blood, lungs, wounds, feces, and the environment was determined by multilocus enzyme electrophoresis. The presence and characteristics of virulence factors were determined by restriction fragment length polymorphism analysis with DNA probes for lasA, lasB,aprA, exoS, exoT,exoU, and ctx and by zymography of staphylolysin, elastase, and alkaline protease. These analyses revealed an epidemic population structure of P. aeruginosa, characterized by frequent recombination in which a particular successful clone may increase, predominate for a time, and then disasappear as a result of recombination. Epidemic clones were found among isolates from patients with keratitis. They were characterized by high activity of a hitherto-unrecognized size variant of elastase, high alkaline protease activity, and possession of the exoUgene encoding the cytotoxic exoenzyme U. These virulence determinants are not exclusive traits in strains causing keratitis, as strains with other properties may cause keratitis in the presence of predisposing conditions. There were no uniform patterns of characteristics of isolates from other types of infection; however, all strains from urinary tract infections possessed the exoS gene, all strains from environment and feces and the major part of keratitis and wound isolates exhibited high elastase and alkaline protease activity, and all strains from feces showed high staphylolysin activity, indicating that these virulence factors may be important in the pathogenesis of these infectious diseases.

Urinary Tract Infections in Patients with Type 1 and Type 2 Diabetes: Etiology, Resistance to Antibacterial Chemicals and Virulence Features

2017 ◽  
Vol 68 (3) ◽  
pp. 566-569 ◽  
Author(s):  
Mihaela Magdalena Mitache ◽  
Carmen Curutiu ◽  
Elena Rusu ◽  
Ramona Bahna ◽  
Mara Ditu ◽  
...  
Keyword(s):  
Urinary Tract ◽  
Virulence Factors ◽  
Urinary Tract Infections ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Diabetic Patients ◽  
Disk Diffusion Test ◽  
Tract Infections ◽  
Susceptibility Profiles ◽  
Diabetes Patients

One of the most frequent chronic complications occurred in diabetes patients are the urinary tract infections (UTIs). This study aimed to investigate the incidence of UTIs in a cohort of 93 (47 males: 46 females) diabetic patients, the prevalence of different microbial species involved and their virulence and antibiotic resistance profiles. The identification of the uropathogenic strains in the positive urine samples was performed using conventional methods and API tests. After identification, the antibiotic susceptibility profiles were established by the standardized disk diffusion method and double disk diffusion test was performed for the confirmation of ESBL and inducible AmpC b �lactamase phenotypes. The isolated strains were tested for the production of different cell associated and soluble virulence factors, i.e.: bacterial adherence to cellular substrata (HeLa cells), hemolysins (hemolysis spot, CAMP-like), amylase, caseinase, aesculin hydrolysis, DNA-ase, lipase and lecithinase. In the analyzed group, the total prevalence of UTIs was of 46%, a higher incidence being observed in the female patients (64%). Similar to other studies, the etiology of UTI in the investigated diabetes patients was dominated by E. coli, followed by Klebsiella sp. strains. The isolated strains preserved good susceptibility rates to quinolones and aminoglycosides and revealed important virulence features, related to their capacity to colonize the cellular substratum and to produce soluble virulence factors involved in persistence, colonization and progression of the infectious process. The high percentage of beta-lactam resistant strains (including carbapenem-resistant ones) requires careful surveillance of the dynamics of susceptibility profiles for limiting the emergence of these strains in community.

scholarly journals Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors

Microbiology ◽  
2009 ◽  
Vol 155 (3) ◽  
pp. 712-723 ◽  
Author(s):  
Valérie Dekimpe ◽  
Eric Déziel
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Virulence Factors ◽  
Transcriptional Regulator ◽  
Homoserine Lactone ◽  
The Other ◽  
Virulence Determinants ◽  
Late Stationary Phase ◽  
Regulatory Systems ◽  
Specific Factors

Pseudomonas aeruginosa uses the two major quorum-sensing (QS) regulatory systems las and rhl to modulate the expression of many of its virulence factors. The las system is considered to stand at the top of the QS hierarchy. However, some virulence factors such as pyocyanin have been reported to still be produced in lasR mutants under certain conditions. Interestingly, such mutants arise spontaneously under various conditions, including in the airways of cystic fibrosis patients. Using transcriptional lacZ reporters, LC/MS quantification and phenotypic assays, we have investigated the regulation of QS-controlled factors by the las system. Our results show that activity of the rhl system is only delayed in a lasR mutant, thus allowing the expression of multiple virulence determinants such as pyocyanin, rhamnolipids and C4-homoserine lactone (HSL) during the late stationary phase. Moreover, at this stage, RhlR is able to overcome the absence of the las system by activating specific LasR-controlled functions, including production of 3-oxo-C12-HSL and Pseudomonas quinolone signal (PQS). P. aeruginosa is thus able to circumvent the deficiency of one of its QS systems by allowing the other to take over. This work demonstrates that the QS hierarchy is more complex than the model simply presenting the las system above the rhl system.

scholarly journals Cerebrospinal fluid (CSF) augments metabolism and virulence expression factors in Acinetobacter baumannii

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jasmine Martinez ◽  
Chelsea Razo-Gutierrez ◽  
Casin Le ◽  
Robert Courville ◽  
Camila Pimentel ◽  
...  
Keyword(s):  
Cerebrospinal Fluid ◽  
Acinetobacter Baumannii ◽  
Virulence Factors ◽  
Atp Synthesis ◽  
Bloodstream Infections ◽  
Model Systems ◽  
Phenotypic Traits ◽  
Virulence Determinants ◽  
Expression Of Genes

AbstractIn a recent report by the Centers for Disease Control and Prevention (CDC), multidrug resistant (MDR) Acinetobacter baumannii is a pathogen described as an “urgent threat.” Infection with this bacterium manifests as different diseases such as community and nosocomial pneumonia, bloodstream infections, endocarditis, infections of the urinary tract, wound infections, burn infections, skin and soft tissue infections, and meningitis. In particular, nosocomial meningitis, an unwelcome complication of neurosurgery caused by extensively-drug resistant (XDR) A. baumannii, is extremely challenging to manage. Therefore, understanding how A. baumannii adapts to different host environments, such as cerebrospinal fluid (CSF) that may trigger changes in expression of virulence factors that are associated with the successful establishment and progress of this infection is necessary. The present in-vitro work describes, the genetic changes that occur during A. baumannii infiltration into CSF and displays A. baumannii’s expansive versatility to persist in a nutrient limited environment while enhancing several virulence factors to survive and persist. While a hypervirulent A. baumannii strain did not show changes in its transcriptome when incubated in the presence of CSF, a low-virulence isolate showed significant differences in gene expression and phenotypic traits. Exposure to 4% CSF caused increased expression of virulence factors such as fimbriae, pilins, and iron chelators, and other virulence determinants that was confirmed in various model systems. Furthermore, although CSF's presence did not enhance bacterial growth, an increase of expression of genes encoding transcription, translation, and the ATP synthesis machinery was observed. This work also explores A. baumannii’s response to an essential component, human serum albumin (HSA), within CSF to trigger the differential expression of genes associated with its pathoadaptibility in this environment.

scholarly journals ANTIBACTERIAL RESISTANCE PATTERN OF PSEUDOMONAS AERUGINOSA ISOLATED FROM CLINICAL SAMPLES AT A GENERAL HOSPITAL IN PADANG, WEST SUMATRA, INDONESIA

2017 ◽  
Vol 10 (8) ◽  
pp. 158
Author(s):  
Rustini Rustini ◽  
Jamsari Jamsari ◽  
Marlina Marlina ◽  
Nasrul Zubir ◽  
Yori Yuliandra
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Resistance ◽  
Clinical Sample ◽  
Opportunistic Pathogen ◽  
Positive Control ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Tract Infections ◽  
Almost All

Objectives: Pseudomonas aeruginosa is an opportunistic pathogen that has an innate resistance to some antibiotics. This bacterium is one of the mostcommon causes of nosocomial infections that include surgical wound infections, burns, and urinary tract infections. The bacteria have been reportedlyresistant to many antibiotics and have developed multidrug resistance (MDR). The objective of the study was to determine the resistance pattern ofP. aeruginosa isolated from clinical samples of patients against some major antibiotics.Methods: Isolates of P. aeruginosa were obtained from clinical sample of urine, sputum, swabs, pus, feces, and blood and cultured in cetrimide agar. P.aeruginosa ATCC 27853 was used as a positive control. The antibacterial susceptibility testing was conducted against 13 antibiotics: Ceftazidime, cefotaxime,ceftriaxone, cefoperazone, ciprofloxacin, levofloxacin, ofloxacin, gentamicin, amikacin, piperacillin, ticarcillin, meropenem, and imipenem. The examinationwas carried out using agar diffusion method of Kirby-Bauer and following the standards from Clinical and Laboratory Standards Institute (CLSI).Results: The results showed that bacterial resistance was established against all tested antibiotics. The highest number of resistance was shownagainst ceftriaxone (44.21%), whereas the most susceptibility was exhibited against amikacin (only 9.47% of resistance). MDR P. aeruginosa (MDRPA)was detected on almost all clinical samples tested, except the feces. The sample with the highest percentage of MDRPA was the pus.Conclusion: The study concludes that the most effective antibiotic against P. aeruginosa is amikacin (91.51%), whereas the most resistance is exhibited to ceftriaxone (43.16%).

scholarly journals Prevalence of antibiotic resistance and blaIMP-1 gene among Pseudomonas aeruginosa strains isolated from burn and urinary tract infections in Isfahan, central Iran

2017 ◽  
Vol 8 (2) ◽  
Author(s):  
Naeimeh Sadat Hashemi ◽  
Meysam Mojiri ◽  
Parivash Yazdani Kachouyi ◽  
Shiva Eskandari ◽  
Mehrsa Mohammadian ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Urinary Tract ◽  
Urinary Tract Infections ◽  
Diffusion Method ◽  
Clinical Samples ◽  
Resistance Pattern ◽  
Public Health Issue ◽  
High Prevalence ◽  
Tract Infections

Pseudomonas aeruginosa is one of the most important opportunistic pathogens responsible for various types of hospital infections. High prevalence of antibiotic resistance in P. aeruginosa strains of human clinical samples cause more severe diseases for a longer period of time. The current research was done in order to study the distribution of blaIMP-1 gene among the imipenem-resistant P. aeruginosa strains isolated from burn and urinary tract infections of hospitalized patients. Two-hundred and forty-three P. aeruginosa isolates recovered from the cases of burn and urinary tract infections of inpatients and outpatients were analysis for antibiotic resistance pattern using the disk diffusion method. Then, imipenem-resistant isolates were further analyzed for distribution of blaIMP-1 gene using the PCR. Of 243 P. aeruginosa isolates, 146 strains (60.08%) were taken from outpatients and 97 strains (39.91%) were taken from inpatients. P. aeruginosa isolates harbored the highest levels of resistance against streptomycin (100%), nalidixic acid (100%), aztreonam (100%), cotrimoxazole (95.47%), ciprofloxacin (88.47%), cefotaxime (84.36%) and gentamycin (83.95%). Inpatients had a relatively higher levels of antibiotic resistance. One-hundred and twenty-one out of 126 (96.03%) imipenem-resistant P. aeruginosa isolates harbored the blaIMP-1 gene. Inpatients also had a relatively higher prevalence of blaIMP-1 gene. High prevalence of blaIMP-1 gene and also imipenemresistant P. aeruginosa are important public health issue. Clinical laboratories should consider the detection of the blaIMP-1 gene among the P. aeruginosa isolates of clinical samples.

scholarly journals Virulence factors and antibiotic resistance in enterococci isolated from food-stuffs

2011 ◽  
Vol 56 (No. 7) ◽  
pp. 352-357 ◽  
Author(s):  
K. Trivedi ◽  
S. Cupakova ◽  
R. Karpiskova
Keyword(s):  
Antibiotic Resistance ◽  
Virulence Factors ◽  
Diffusion Method ◽  
Haemolytic Activity ◽  
Virulence Determinants ◽  
Disk Diffusion Method ◽  
Specific Pcr ◽  
Virulence Potential ◽  
Enterococcal Species ◽  
Species Specific

A collection of 250 enterococci isolated from various food-stuffs were used to investigate seven virulence determinants and the microbial susceptibility of eight antibiotics. Species-specific PCR revealed the presence of E. faecalis (127 isolates), E. faecium (77 isolates), E. casseliflavus (21 isolates), E. mundtii (19 isolates) and E. durans (six isolates). Multiplex PCR for virulence factors showed that from a total 250 isolates, 221 (88.4%) carried one or more virulence-encoding genes. β-Haemolytic activity was also evident in enterococcal species other than E. faecalis and E. faecium. Species other than E. faecalis and E. faecium isolated from food are also seen to harbour the potential for virulence. Antimicrobial susceptibility testing using the disk diffusion method showed that of the total 250 isolates, 114 (46%) were resistant to cephalothin and 94 (38%) to ofloxacin. Lower antibiotic resistance was seen with ampicillin, chloramphenicol, gentamicin and teicoplanin. None of the isolates was found to be resistant to vancomycin. The results of this study show that food can play an important role in the spread of enterococci with virulence potential through the food chain to the human population.

scholarly journals 1047. Global Surveillance: Susceptibility of Ceftolozane–Tazobactam Against Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa Isolates Collected From Bloodstream Infections in the United States From 2015 to 2017

2018 ◽  
Vol 5 (suppl_1) ◽  
pp. S313-S313
Author(s):  
S J Ryan Arends ◽  
Dee Shortridge ◽  
Mariana Castanheira ◽  
Jennifer M Streit ◽  
Robert K Flamm
Keyword(s):  
United States ◽  
Escherichia Coli ◽  
Pseudomonas Aeruginosa ◽  
Klebsiella Pneumoniae ◽  
Bloodstream Infections ◽  
The United States ◽  
Research Support ◽  
Broth Microdilution Method ◽  
The Us ◽  
Tract Infections

Abstract Background Ceftolozane–tazobactam (C-T) is an antibacterial combination of a novel antipseudomonal cephalosporin and a β-lactamase inhibitor. C-T was approved by the US Food and Drug Administration in 2014 and by the European Medicines Agency in 2015 to treat complicated urinary tract infections, acute pyelonephritis, and complicated intra-abdominal infections. The Program to Assess Ceftolozane-Tazobactam Susceptibility (PACTS) monitors Gram-negative (GN) isolates resistant to C-T worldwide. In the current study, isolates were collected from patients hospitalized with bloodstream infections (BSIs) from 2015 to 2017 within the United States. Methods A total of 3,377 prevalence-based BSI GN isolates, including Escherichia coli (EC; 1,422), Klebsiella pneumoniae (KPN, 630), and Pseudomonas aeruginosa (PSA; 344), were collected during 2015 to 2017 from 32 PACTS hospitals in the United States. Isolates were tested for C-T susceptibility by CLSI broth microdilution method in a central monitoring laboratory (JMI Laboratories). Other antibiotics tested were amikacin (AMK), cefepime (FEP), ceftazidime (CAZ), colistin (COL), levofloxacin (LVX), meropenem (MEM), and piperacillin–tazobactam (TZP). Antibiotic-resistant phenotypes analyzed (CLSI, 2018) for EC and KPN included carbapenem-R (CR) and non-CR extended-spectrum β-lactamase (ESBL); as well as CAZ-nonsusceptible (CAZ-NS), MEM-NS, and COL-NS PSA. Results Of the 3,377 BSI GN isolates, 3,219 (95.3%) had a C-T MIC ≤ 4 mg/L. The three most prevalent GN species isolated from BSIs were EC (42.1%), KPN (18.7%), and PSA (10.2%). The %S of C-T and comparators for the top three pathogens are shown in the table. C-T showed activity against these isolates with %S of ≥96.0% against all three species. Of the comparators tested, AMK and COL also had high %S against these isolates. Conclusion C-T demonstrated activity against the most prevalent contemporary GN isolates from BSIs in the US. C-T was the only beta-lactam that had ≥96%S against all three species: EC, KPN, and PSA. For PSA, C-T maintained activity (>90%S) against isolates resistant to CAZ, TZP, and MEM. These data suggest that C-T may be a useful treatment for GN BSI. Disclosures S. J. R. Arends, Merck: Research Contractor, Research support. D. Shortridge, Merck: Research Contractor, Research support. M. Castanheira, Merck: Research Contractor, Research support. J. M. Streit, Merck: Research Contractor, Research support. R. K. Flamm, Merck: Research Contractor, Research support.

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