scholarly journals Interplay of Efflux System, ampC, and oprD Expression in Carbapenem Resistance of Pseudomonas aeruginosa Clinical Isolates

2006 ◽  
Vol 50 (5) ◽  
pp. 1633-1641 ◽  
Author(s):  
John Quale ◽  
Simona Bratu ◽  
Jyoti Gupta ◽  
David Landman
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Target Genes ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Carbapenem Resistant ◽  
High Level ◽  
Increased Activity

ABSTRACT Carbapenems are important agents for the therapy of infections due to multidrug-resistant Pseudomonas aeruginosa; the development of carbapenem resistance hampers effective therapeutic options. To assess the mechanisms leading to resistance, 33 clinical isolates with differing degrees of carbapenem susceptibility were analyzed for the expression of the chromosomal β-lactamase (ampC), the porin that is important for the entry of carbapenems (oprD), and the proteins involved in four efflux systems (mexA, mexC, mexE, and mexX). Real-time reverse transcriptase PCR was performed using primers and fluorescent probes for each of the target genes. The sequencing of regulatory genes (ampR, mexR, nalC, nalD, mexT, and mexZ) was also performed. Diminished expression of oprD was present in all imipenem- and meropenem-resistant isolates but was not required for ertapenem resistance. Increased expression of ampC was not observed in several isolates that were overtly resistant to carbapenems. Increased expression of several efflux systems was observed in many of the carbapenem-resistant isolates. Increased efflux activity correlated with high-level ertapenem resistance and reduced susceptibility to meropenem and aztreonam. Most isolates with increased expression of mexA had mutations affecting nalC and/or nalD. Two isolates with mutations leading to a premature stop codon in mexZ had markedly elevated mexX expressions, although mutations in mexZ were not a prerequisite for overexpression. β-Lactam resistance in clinical isolates of P. aeruginosa is a result of the interplay between diminished production of oprD, increased activity of ampC, and several efflux systems.

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 New Delhi Metallo-β-lactamase (NDM)-mediated Carbapenem-Resistant Pseudomonas aeruginosa Clinical Isolates in Sudan

2018 ◽  
pp. 1-5
Author(s):  
Salma Elnour Rahma Mohamed ◽  
Alfadil Alobied ◽  
Mohamed Ibrahim Saeed ◽  
Wafa Mohamed Hussien
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Teaching Hospital ◽  
Carbapenem Resistance ◽  
Clinical Isolates ◽  
Diffusion Method ◽  
New Delhi ◽  
Army Hospital ◽  
Carbapenem Resistant ◽  
Wide Range ◽  
Data Documentation

Carbapenem resistance mediated by NDM is particularly gruesome as this carbapenemase can hydrolyze a wide range of β-lactam antibiotics. Aim: This study aims to detect NDM mediated carbapenem resistance in clinical isolates of Pseudomonas aeruginosa. Materials and Methods: 50 multi-drug resistant clinical urinary isolates of Pseudomonas aeruginosa from three major hospitals in Khartoum state Sudan; Khartoum Teaching Hospital, Medical Army Hospital and Omdurman teaching hospital, in period from July 2016 to September 2017, were investigated for carbapenem resistance using standard disc diffusion method and underwent real-time PCR to detect carbapenem resistance gene blaNDM. Data were analyzed using IBM SPSS. Results: 60% were positive for the blaNDM, 82% were resistant to Imipenem and 75% of the samples were resistant to Meropenem. Conclusion: The emergence of carbapenem resistance is a global problem that requires earnest attention. To make the suitable preventive measures, the emergence of these genes must be monitored closely. Our findings revealed that carbapenem-resistant due to the gene blaNDM is accounted for 60% of the cases, and due to lack of proper data documentation about the emergence of this gene in Sudan, these cases to the best of our knowledge are the first to be reported in Sudan.

scholarly journals Ceftazidime–avibactam and ceftolozane–tazobactam susceptibility of multidrug resistant Pseudomonas aeruginosa strains in Hungary

2020 ◽  
pp. 1-5 ◽  
Author(s):  
Dustin O'Neall ◽  
Emese Juhász ◽  
Ákos Tóth ◽  
Edit Urbán ◽  
Judit Szabó ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Inhibitory Concentration ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Test Results ◽  
Diffusion Test ◽  
Microdilution Method ◽  
Carbapenem Resistant ◽  
Gradient Diffusion ◽  
Broth Microdilution Method

Abstract Our objective was to compare the activity ceftazidime-avibactam (C/A) and ceftolozane–tazobactam (C/T) against multidrug (including carbapenem) resistant Pseudomonas aeruginosa clinical isolates collected from six diagnostic centers in Hungary and to reveal the genetic background of their carbapenem resistance. Two hundred and fifty consecutive, non-duplicate, carbapenem-resistant multidrug resistant (MDR) P. aeruginosa isolates were collected in 2017. Minimal inhibitory concentration values of ceftazidime, cefepime, piperacillin/tazobactam, C/A and C/T were determined by broth microdilution method and gradient diffusion test. Carbapenem inactivation method (CIM) test was performed on all isolates. Carbapenemase-encoding blaVIM, blaIMP, blaKPC, blaOXA-48-like and blaNDM genes were identified by multiplex PCR. Of the isolates tested, 33.6& and 32.4& showed resistance to C/A and C/T, respectively. According to the CIM test results, 26& of the isolates were classified as carbapenemase producers. The susceptibility of P. aeruginosa isolates to C/A and C/T without carbapenemase production was 89& and 91&, respectively. Of the CIM-positive isolates, 80& were positive for blaVIM and 11& for blaNDM. The prevalence of Verona integron-encoded metallo-beta-lactamase (VIM)-type carbapenemase was 20.8&. NDM was present in 2.8& of the isolates. Although the rate of carbapenemase-producing P. aeruginosa strains is high, a negative CIM result indicates that either C/A or C/T could be effective even if carbapenem resistance has been observed.

Geographic Patterns of Carbapenem-resistant Pseudomonas aeruginosa in the Asia-Pacific Region: Results from the Antimicrobial Testing Leadership and Surveillance (ATLAS) program, 2015–2019

2021 ◽  
Author(s):  
Yu-Lin Lee ◽  
Wen-Chien Ko ◽  
Po-Ren Hsueh
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Agents ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Asia Pacific ◽  
Pacific Region ◽  
Asia Pacific Region ◽  
Carbapenem Resistant ◽  
Broth Microdilution Method ◽  
Resistance Patterns

Pseudomonas aeruginosa is a common pathogen that is associated with multidrug-resistant (MDR) and carbapenem-resistant (CR) phenotypes; therefore, we investigated its resistance patterns and mechanisms by using data from the Antimicrobial Testing Leadership and Surveillance (ATLAS) program in the Asia-Pacific region during 2015–2019. MICs were determined using the broth microdilution method. Genes encoding major extended-spectrum β-lactamases and carbapenemases were investigated by multiplex PCR assays. Susceptibility was interpreted using the Clinical and Laboratory Standards Institute (CLSI) breakpoints. A total of 6,349 P. aeruginosa isolates were collected in the ATLAS program between 2015 and 2019 from 14 countries. According to the CLSI definitions, the numbers (and rates) of CR and MDR P. aeruginosa were 1,198 (18.9%) and 1,303 (20.5%), respectively. For 747 of the CR P. aeruginosa strains that were available for gene screening, 253 β-lactamases genes were detected in 245 (32.8%) isolates. The most common gene was bla VIM (29.0, 71/245), followed by bla NDM (24.9%, 61/245) and bla VEB (20.8%, 51/245). The resistance patterns and associated genes varied significantly between the countries in the Asia-Pacific region. India had the highest rates of carbapenem resistance (29.3%, 154/525) and gene detection (17.7%, 93/525). Compared to those harboring either class A or B β-lactamase genes, the CR P. aeruginosa without detected β-lactamase genes had lower MICs for most of the antimicrobial agents, including ceftazidime/avibactam and ceftolozane/tazobactam. In conclusion, MDR and CR P. aeruginosa infections pose a major threat, particularly those with detected carbapenemase genes. Continuous surveillance is important for improving antimicrobial stewardship and antibiotic prescriptions.

scholarly journals Mutational and acquired carbapenem resistance mechanisms in multidrug resistant Pseudomonas aeruginosa clinical isolates from Recife, Brazil

2015 ◽  
Vol 110 (8) ◽  
pp. 1003-1009 ◽  
Author(s):  
Felipe Lira de Sá Cavalcanti ◽  
Cristina Rodríguez Mirones ◽  
Elena Román Paucar ◽  
Laura Álvarez Montes ◽  
Tereza Cristina Leal-Balbino ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Resistance Mechanisms ◽  
Clinical Isolates

scholarly journals 2291. Evaluation of Multidrug-Resistant Pseudomonas aeruginosa Isolates in Patients Receiving Ceftolozane/tazobactam

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S785-S785
Author(s):  
Emily C Bodo ◽  
Aisling Caffrey ◽  
Vrishali Lopes ◽  
Jaclyn A Cusumano ◽  
Laura A Puzniak ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibiotic Resistance ◽  
Retrospective Study ◽  
Carbapenem Resistance ◽  
Multidrug Resistant ◽  
Veterans Affairs ◽  
Carbapenem Resistant ◽  
Clinical Culture ◽  
Resistance Rates ◽  
Lactamase Inhibitor

Abstract Background Multidrug-resistant (MDR) Pseudomonas aeruginosa is a challenging pathogen to treat. Ceftolozane/tazobactam (C/T) is a combination cephalosporin and β-lactamase inhibitor that has demonstrated activity against MDR P. aeruginosa, including carbapenem-resistant isolates. The objective of this study was to evaluate multidrug resistance in P. aeruginosa isolates obtained from patients treated with C/T across the Veterans Affairs (VA) Healthcare System nationally. Methods Hospitalized patients who received at least 1 dose of CT between January 2015 and April 2018 and had a positive P. aeruginosa culture were included in this retrospective study. Culture source and antimicrobial susceptibility reports were assessed for each P. aeruginosa isolate. Isolates were categorized as multidrug-resistant based on the Centers for Disease Control (CDC) definition. Resistance rates were categorized by source of culture. Results We identified 174 positive P. aeruginosa cultures among 154 patients who received at least one dose of C/T during the study period. The most common sources of isolates were lung (40% of patients), urine (21%), skin and soft tissue (15%), blood (14%), and bone/joint (14%). Most patients (98.1%) had isolates that were MDR, with high rates of carbapenem (84.4%), extended-spectrum cephalosporin (82.5%), and fluoroquinolone (79.9%) resistance. In this cohort, 50.6% of patients received at least one antibiotic prior to initiating C/T to which their clinical culture was not susceptible. Conclusion Antibiotic resistance was high in this cohort of patients with P. aeruginosa, and as a result, use of non-susceptible antibiotics occurred in 50.6% of patients before C/T was started. The high carbapenem resistance rates are of great clinical concern, but highlight an area of utilization for C/T given its activity against carbapenem-resistant P. aeruginosa. Disclosures All authors: No reported disclosures.

scholarly journals Molecular Detection of bla OXA-48 Gene Encoding Carbapenem Resistance Pseudomonas aeruginosa Clinical Isolates from Khartoum State Hospitals, Sudan

2020 ◽  
Author(s):  
Doha Omer Ali ◽  
Mohamed M.A. Nagla
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Teaching Hospital ◽  
Carbapenem Resistance ◽  
Clinical Isolates ◽  
Clinical Samples ◽  
P Value ◽  
Gene Encoding ◽  
State Hospitals ◽  
Carbapenem Resistant ◽  
Different Strains

AbatractCarbapenem resistance in Pseudomonas.aeruginosa is particularly worrisome because this class of β-lactam represents the last therapeutic resource for control of bacterial infection.So this study aimed to detect the frequency of bla OXA-48 resistance gene among Pseudomonas aeruginosa clinical isolates during the period from November 2018 to November 2019.Hundred Pseudomonas aeruginosa clinical isolates, 81 carbapenems (imipenem meropenem) resistant and 19 carbapenems sensitive were collected from Omdurman Teaching Hospital, Fedail Hospital and Soba Teaching Hospital in Khartoum State-Sudan. All isolates were re-identified using conventional bacteriological techniques, their susceptibility to carbapenems were tested using Kirby-Bauer method for confirmation and investigated for the presence of the bla OXA-48 gene using conventional PCR technique.60 (60.0%) out of 100 Pseudomonas aeruginosa clinical isolates were positive for blaOXA-48 gene. Out of 81 carbapenem resistant isolates 54(66.7%) were positive for bla OXA-48 gene, while among the (19) carbapenem sensitive isolates 6 (31.6%) were positive for blaOXA-48 gene. There was statistically significant association between carbapenem resistant isolates and the presence of blaOXA-48 gene (P-value = 0.006).Wound swabs were the predominant clinical samples detected harboring bla OXA-48 gene both among the sensitive 5 (83.3%) and carbapenem resistant isolates 29(53.7) (P.value> 0.05).Our findings revealed high frequency of bla OXA-48 among carbapenem resistant isolates so identification of bla OXA-48 producing strains and taking efforts to reduce the rate of transferring these gene between the different strains is essential for optimization of therapy and improves of patients outcomes.

scholarly journals Phenotypic and genetic analysis of virulence factors in multidrug- sensitive and multidrug-resistant clinical isolates of Pseudomonas aeruginosa

2021 ◽  
Vol 10 (11) ◽  
pp. e457101120032
Author(s):  
Stephanie Targino Silva ◽  
Jailton Lobo da Costa Lima ◽  
Marcelle Aquino Rabelo ◽  
Armando Monteiro Bezerra Neto ◽  
Lílian Rodrigues Alves ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Phospholipase C ◽  
Virulence Factors ◽  
Alkaline Protease ◽  
Tertiary Hospital ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Protease Production ◽  
High Level ◽  
Almost All

This study aimed to correlate the pattern of antimicrobial susceptibility, phenotypic production of virulence factors, the occurrence of virulence factors genes and the clonal profile of clinical isolates of Pseudomonas aeruginosa of a tertiary hospital in Recife-PE. The 30 clinical isolates (15 multidrug-sensitive (MDS) and 15 multidrug-resistant (MDR)) were analyzed using phenotypic methods to detect virulence factors (alkaline protease, hemolysin, phospholipase C, lipase, and pigments). The detection of the aprA, lasA, lasB, plcH, and toxA genes was performed through specific PCRs, and the clonal profile was assessed using ERIC-PCR. The results revealed cephalosporins being the class eliciting the highest percentage of resistance; the MDR isolates were all resistant. Among the MDS isolates, all were sensitive to carbapenems and quinolones. The MDR isolates produced less virulence factors such as pyocyanin and lipase, and exhibited lower expression of toxA and lasA genes, whereas the MDS isolates produced less hemolysin and phospholipase C. There was no difference between the groups for alkaline protease production and aprA gene expression. All the isolates produced pyocyanin and expressed lasB and plcH genes. A great genetic diversity was found, and it was possible to observe 28 genetic profiles. Clones were present among the MDR isolates. The occurrence of virulence factors in almost all the isolates studied suggests their high level of pathogenicity, demonstrating that this pathogen is capable of accumulating numerous virulence factors, and in some cases, is associated with multidrug resistance, which makes it difficult to treat these infections.

scholarly journals Carbapenem Resistance Mechanisms in Pseudomonas aeruginosa Clinical Isolates

2001 ◽  
Vol 45 (2) ◽  
pp. 480-484 ◽  
Author(s):  
Hyunjoo Pai ◽  
Jong-Won Kim ◽  
Jungmin Kim ◽  
Ji Hyang Lee ◽  
Kang Won Choe ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Amino Acid Substitution ◽  
Carbapenem Resistance ◽  
Resistance Mechanisms ◽  
Clinical Isolates ◽  
Efflux System ◽  
Clinical Strains ◽  
Carbapenem Resistant

ABSTRACT In order to define the contributions of the mechanisms for carbapenem resistance in clinical strains of Pseudomonas aeruginosa, we investigated the presence of OprD, the expressions of the MexAB-OprM and MexEF-OprN systems, and the production of the β-lactamases for 44 clinical strains. All of the carbapenem-resistant isolates showed the loss of or decreased levels of OprD. Three strains overexpressed the MexAB-OprM efflux system by carrying mutations inmexR. These three strains had the amino acid substitution in MexR protein, Arg (CGG) → Gln (CAG), at the position of amino acid 70. None of the isolates, however, expressed the MexEF-OprN efflux system. For the characterization of β-lactamases, at least 13 isolates were the depressed mutants, and 12 strains produced secondary β-lactamases. Based on the above resistance mechanisms, the MICs of carbapenem for the isolates were analyzed. The MICs of carbapenem were mostly determined by the expression of OprD. The MICs of meropenem were two- to four-fold increased for the isolates which overexpressed MexAB-OprM in the background of OprD loss. However, the elevated MICs of meropenem for some individual isolates could not be explained. These findings suggested that other resistance mechanisms would play a role in meropenem resistance in clinical isolates of P. aeruginosa.

Sign in / Sign up

Export Citation Format

Share Document