Determination of imipenem efflux-mediated resistance in Acinetobacter spp., using an efflux pump inhibitor

Author(s):  
Ghazale Amiri ◽  
Maryam Abbasi Shaye ◽  
Masoumeh Bahreini ◽  
Asghar Mafinezhad ◽  
Kiarash Ghazvini ◽  
...  

Background and Objectives: In recent years, reports of Acinetobacter strains resistant to all known antibiotics have caused a great concern in medical communities. Overexpression of efflux pumps is one of the major causes of resistance in bacteria. The aim of this study was to investigate the role of efflux pumps in conferring resistance to imipenem in clinically important Acinetobacter spp; Acinetobacter baumannii and Acinetobacter lwoffii. Materials and Methods: A total number of 46 clinical Acinetobacter isolates, including 33 A. baumannii and 13 A. lwoffii isolates, previously collected from Shahid Kamyab and Ghaem hospitals of Mashhad, Iran were used in this study. Imipenem susceptibility testing was carried out by the disc diffusion method. Imipenem minimum inhibitory concentration (MIC) for resistant Acinetobacter isolates were determined both in the presence and absence of the efflux pumps inhibitor, carbonyl cyanide 3-chlorophenylhydrazone (CCCP). Results: Resistance to imipenem was observed in 38 isolates including 30 A. baumannii and 8 A. lwoffii isolates. Experiments in the presence of CCCP showed a 2 to 16384 fold reduction in imipenem MICs in 14 A. baumannii and 2 A. lwoffii isolates. Conclusion: The results obtained showed high levels of resistance to imipenem and contribution of efflux pumps in conferring resistance in both Acinetobacter species in this study. Moreover, imipenem efflux mediated resistance highlights the importance of this mechanism not only in A. baumannii but also in non-baumannii Acinetobacter Spp. which have been neglected in antibiotic resistance studies.

2016 ◽  
Vol 10 (06) ◽  
pp. 600-604 ◽  
Author(s):  
Mahshid Talebi-Taher ◽  
َAli Majidpour ◽  
Abbas Gholami ◽  
Samira Rasouli-Kouhi ◽  
Maryam Adabi

Introduction: Multidrug resistance in Pseudomonas aeruginosa may be due to efflux pump overexpression. This study phenotypically examined the role of efflux pump inhibitors in decreasing antibiotic cross-resistance between beta-lactams, fluoroquinolones, and aminoglycosides in P. aeruginosa isolates from burn patients in Iran. Methodology: A total of 91 phenotypically and genotypically confirmed P. aeruginosa samples were studied. Multidrug cross-resistance was determined using the disk diffusion method and minimum inhibitory concentration (MIC) test. The contribution of efflux pumps was determined by investigating MIC reduction assay to markers of beta-lactams, fluoroquinolones, and aminoglycosides in the absence and presence of an efflux pump inhibitor. All the isolates were also tested by polymerase chain reaction for the presence of mexA, mexC, and mexE efflux genes. Results: Of the isolates, 81 (89%) and 83 (91.2%) were multidrug resistant according to the disk diffusion and MIC method, respectively. Cross-resistance was observed in 67 (73.6%) and 68 (74.7%) of isolates according to the disk diffusion and MIC method, respectively. In the presence of the efflux pump inhibitor, twofold or higher MIC reduction to imipenem, cefepime, ciprofloxacin, and gentamicin was observed in 59, 65, 55, and 60 isolates, respectively. Except for two isolates that were negative for mexC, all isolates were positive for mexA, mexC, and mexE genes simultaneously. Conclusion: Efflux pumps could cause different levels of resistance based on their expression in clinical isolates. Early detection of different efflux pumps in P. aeruginosa could allow the use of other antibiotics and efflux pump inhibitors in combination with antibiotic therapy.


2021 ◽  
Vol 30 (2) ◽  
pp. 27-34
Author(s):  
Hadir A.S. Okasha ◽  
Nancy Y. Omar ◽  
Azza M. ElHefnawy ◽  
May M. Elghamrawi

Background: P. aeruginosa exhibits several efflux pump systems that allow it to be resistant to several antimicrobial agents. Phenylalanine arginyl β-naphthylamide (PAβN) is an Efflux pump inhibitor (EPI) that can inhibit several multidrug efflux pumps. Objective: This study aimed to detect the efflux pump activity in FQ resistant P. aeruginosa, and to investigate the role of PAβN on FQ resistance. Methodology: P. aeruginosa isolates were subjected to antibiotic susceptibility testing by disc diffusion and those resistant to ciprofloxacin and levofloxacin were subjected to MIC detection before and after addition of PAβN. Also reverse transcription RT PCR was done for detection of mexA, mexC, mexE and mexX genes overexpression in the FQ resistant strains. Results: After the addition of PAβN, 95.9% and 94.5% of the isolates showed reduction in MICs of ciprofloxacin and levofloxacin respectively, 8.20% and 27.4% of the isolates restored susceptibility to those drugs respectively and 8.20% reverted to levofloxacin intermediate breakpoint. MexE was the most common efflux pump overexpressed, followed by mexX and mexA. When using EPI 96.8% and 95.3% of the isolates showed both overexpression and reduction of ciprofloxacin and levofloxacin MIC respectively. Using a cut- off point of ≥4 fold reduction in levofloxacin MIC discriminates efflux pump overexpressing from non-overexpressing isolates, (sensitivity of 70%, specificity of 67%). Conclusion: Efflux pump mediated resistance is an important mechanism contributing to multidrug resistance in P.aeruginosa as proven phenotypically and genotypically, with mexE being the most commonly expressed. The addition of PAβN to levofloxacin could be used as a phenotypic test for detection of efflux pump overexpressing isolates and may be effective to restore the levofloxacin susceptibility.


2020 ◽  
Vol EJMM29 (4) ◽  
pp. 17-25
Author(s):  
Asmaa M. Elbrolosy ◽  
Amira H. Elkhayat ◽  
Dina M. Hassan ◽  
Eman H. Salem

Background: Multidrug-resistant pathogens have been on the rise during the last few years. Pseudomonas aeruginosa is commonly encountered in nosocomial infections with remarkable ability to develop antimicrobial resistance of which carbapenems are of great concern. Objectives: To explore the role of MexAB-OprM and MexXY-OprM efflux pumps overexpression as carbapenems resistance mechanisms among nosocomial P. aeruginosa isolates at both Menoufia and Kasr Al Ainy University Hospitals by phenotypic and molecular characterization methods. Methodology: A total of 120 P. aeruginosa isolates were collected from patients with hospital-acquired infections and subjected to antibiotic susceptibility testing by the Kirby-Bauer disk diffusion method. Carbapenems-resistant isolates were selected and investigated phenotypically for the contribution of MexAB-OprM and MexXY-OprM efflux pumps by both disk synergy and MIC reduction assays with cyanide-m-chlorophenyl hydrazone (CCCP) as an efflux pump inhibitor. Real time PCR assay verified the existence of mexA and mexX genes as regulators of MexAB-OprM and MexXY-OprM overexpression. Laboratory results were correlated with data regarding patients' clinical findings as well as risk factors. Results: Out of 120 P. aeruginosa isolates, 88 (73.3%) isolates were carbapenems-resistant of which 100% were MDR isolates. The highest resistance rate was for piperacillin and piperacillin/tazobactam (100% for each) and the lowest rate was seen against colistin (7.5%).The RT-PCR assay revealed that, 54/88 (61.3%) P. aeruginosa isolates harbored the target genes: 21 isolates (38.9%) were positive for mexA alone, 12 isolates (22.2%) were positive for mexX alone and 21 isolates (38.9%) showed co-existence of the two genes. In relation to PCR results, the sensitivity, specificity and accuracy of CCCP disk synergy test respectively were 46%, 94% and 64.8% while, those for MIC method were 88.9%, 55.9% and 76.1% respectively. Conclusion: Carbapenems resistance mediated by the overexpression of efflux pumps has also now emerged. Early recognition of this resistance mechanism to allow the use of alternative b-lactams is imperative.


2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Brice E. N. Wamba ◽  
Armelle T. Mbaveng ◽  
Paul Nayim ◽  
Joachim K. Dzotam ◽  
Ornella J. T. Ngalani ◽  
...  

Background. In this study, 18 methanol extracts from Cameroonian edible plants were tested for their antibacterial activities against 26 strains ofS. aureus; the role of efflux pumps in the resistance of tested bacteria and the antibiotic resistance-modulating activities against selected multidrug-resistant (MDR) phenotypes were also investigated.Methods. Broth microdilution assay was used to evaluate the antibacterial activity, the role of efflux pumps, and the antibiotic resistance-modulating effects of plant extracts.Results. Extracts fromDacryodes edulisseeds (DES) andDacryodes edulisbark (DEB) were active against all 26 tested bacterial strains, within the minimal inhibitory concentration (MIC) range of 256–1024 µg/mL. MIC values varied from 64 to 1024 µg/mL against 96.2% of the 26 tested bacteria forPhaseolus vulgarisleaves (PVL), 92.3% forAzadirachta indicabark (AIB),Dacryodes edulisleaves (DEL), andRicinodendron heudelotiileaves (RHL). The lowest MIC value of 64 µg/mL was obtained with the extract fromCucurbita maximabeans (CMB) against MRSA4 strain and fromUapaca guineensisbark (UGB) against MRSA9 strain. Bacterial efflux pump inhibitor (EPI), carbonyl cyanidem-chlorophenyl hydrazone (CCCP), improved the activity of DES and UGB as well as that of extracts fromHibiscus esculentusleaves (HEL) andUapaca guineensisleaves (UGL) against resistantS. aureusstrains. Antibiotic-modulating effects against more than 70% of theS. aureusstrains tested were obtained when RHL (at MIC/2) was combined with CIP, ERY, and KAN (88.89%), CHL (88.89%), TET (77.78%), and STR (88.89%).Conclusion. The present study demonstrated that the 13 tested plants had antistaphylococcal effects and that DES, HEL, UGL, and UGB could be used in combination with EPI to combat resistance toStaphylococcus aureus. Also, it demonstrated that some studied extracts and mostly RHL could be used as antibiotic resistance modulators to fight against resistant strains ofS. aureus.


Author(s):  
Shahid Raza ◽  
Hitender Gautam ◽  
Bhavna Maheshwari ◽  
Sarita Mohapatra ◽  
Seema Sood ◽  
...  

Introduction: Antimicrobial resistance of Acinetobacter baumannii(A. baumannii) are rapidly emerging, becoming non-responsive to most of the commonly prescribed antibiotics and leaving us with few treatment options and galloping treatment costs. Aim: To study the effect of Efflux Pump Inhibitor (EPI) Carbonyl Cyanide 3-Chlorophenylhydrazone (CCCP) on Multidrug Resistance (MDR) A. baumannii isolates from different sterile body fluids. Materials and Methods: A total of 40 Acinetobacter species isolates from different sterile body fluids i.e., Cerebrospinal Fluid (CSF), ascitic fluid, pleural fluid, and peritoneal fluid were collected and identified by Matrix Assisted Laser Desorption/Ionisation-Time Of Flight (MALDI-TOF), Biomerieux, France. Minimum Inhibitory Concentration (MIC) of A. baumannii was determined by automated VITEK-2 Antimicrobial Susceptibility Testing (AST) system (Biomerieux, France). In addition, MIC of the isolates, grown on Mueller-Hinton Agar (MHA) plate with 15 μg/mL with EPI CCCP (Sigma Aldrich, US) was determined. For Tigecycline, MIC was determined by Broth Microdilution (BMD) method. Results: Out of 40 isolates, 34 (85%) were A. baumannii and 6 (15%) were Acinetobacter junii. Most of the Acinetobacter spps were MDR and only susceptible to few antibiotics. Most effective antibiotic was Tigecycline 25 (73.52%) followed by Co-trimoxazole 10 (29.41%). Similarly, Out of 40 isolates, 2 to 64 folds reductions in MIC was observed due to CCCP in 10 (25%) isolates for various antibiotics. Likewise, for Tigecycline, 2 to 4 folds reductions in MIC value (One strain changed from intermediate to sensitive) was observed by VITEK-2 AST which corroborated with reduction in MIC by BMD after addition of CCCP. Conclusion: MDR A. baumannii are spreading rapidly. There is the need to overcome the antimicrobial resistance by investigating resistance inhibiting substance that will help to restore antimicrobial susceptibility and bringing back the existing antibiotics in prescription.


2020 ◽  
Author(s):  
Javad rasouli ◽  
Behnam hashemi ◽  
Hamed Afkhami ◽  
Mansoor Khaledi ◽  
Reza valadan ◽  
...  

Abstract Objectives Pseudomonas aeruginosa is one of the most important causes of Hospital infection especially in burn victims. The current study aimed to determine antibiotic resistance of the efflux Pumps MexAB-Opr M. In the present study, 115 samples of urine, blood, sputum, and ICU were collected from the reconstructive section of the patients. The drug susceptibility patterns were determined by disk diffusion method. Phenotypic activity of the efflux pump from the E-test was evaluated, in the presence and without the presence of efflux pump inhibitor. The MexAB gene was analyzed by PCR reaction. Results The resistant isolated was shown to be Ciprofloxacin 33.91%, Nurfloxacin 38.26%, Gentamicin 71.7%, Nalidixic acid 95.95%, Ceftazidim 38.46%, Emipenem 24.34%, Meropenem 26.36%, and Cefotaxim 40.86%. The highest and lowest resistance rates were Co-trimoxazole and Piperacilin, respectively. The findings of PCR reaction among 115 P. aeruginosa isolates indicated that 62.62% was MexAB gene. The results of MIC with E-test revealed that the role of efflux pumps in antibiotic resistance was 19 isolated. Due to the importance of antibiotic resistance to investigate other efflux pumps, comparison of efflux pump involvement in antibiotic resistance, and relationship between efflux pumps MexAB-Opr M are highly required and suggested.


2004 ◽  
Vol 48 (9) ◽  
pp. 3621-3624 ◽  
Author(s):  
Renaud Chollet ◽  
Jacqueline Chevalier ◽  
André Bryskier ◽  
Jean-Marie Pagès

ABSTRACT The role of the AcrAB-TolC pump in macrolide and ketolide susceptibility in Escherichia coli and Enterobacter aerogenes was studied. Efflux pump inhibitor restored erythromycin, clarithromycin, and telithromycin susceptibilities to multidrug-resistant isolates. No modification of telithromycin accumulation was detected in E. aerogenes acrAB or tolC derivatives compared to that in the parental strain. Two independent efflux pumps, inhibited by phenylalanine arginine β-naphthylamide, expel macrolides and telithromycin in E. aerogenes.


2019 ◽  
Vol 17 (1) ◽  
pp. 110-120
Author(s):  
G. C. AGU ◽  
B. T. THOMAS ◽  
O. O. SALAMI ◽  
O. D. POPOOLA

Pseudomonas aeruginosa is an important opportunistic pathogen and one of the leading causes of multi-drug resistant nosocomial infections. This study was therefore carried out to determine the resistance nature, and the role of efflux pump in multidrug resistance of Pseudomonas aeruginosa isolated from different environmental sources using the efflux pump inhibitor, Carbonyl Cyanide 3-Chlorophenylhydrazone (CCCP). A total of 220 environmental samples were collected and processed following standard techniques. Susceptibility to antibiotics was performed using disc diffusion methods as described by the Clinical and Laboratory Standards Institute. Activity of the efflux pump system was carried out using the efflux pump inhibitor, CCCP. Results obtained identified 100 (45.5%) Pseudomonas aeruginosa and 72 (32.7%) other strains of Pseudomonas spp. The susceptibility testing revealed that all the identified strains of Pseudomonas aeruginosa that were subjected to susceptibility test were significantly resistant to ampicillin and cefotaxime, But the  resistance profile of isolates to tetracycline, chloramphenicol, ceftriaxone, cefuroxime and perfloxacin were 93%, 72.1%, 79.1%, 58.1% and 51.2% respectively. However, imipenem was the most sensitive (100%), followed by cefepime (65%) and gentamicin (44%). Carbonyl Cyanide 3-Chlorophenylhydrazone decreased the minimum inhibitory concentration (MIC) of the isolates by 2 folds. Results obtained have shown the ubiquitous presence of multi-drug resistant P. aeruginosa from the environmental samples examined. Furthermore, it indicated the role of efflux pump in antibiotics resistance in P. aeruginosa isolates which indicate that P. aeruginosa strains from environmental sources could resist antibiotics by the efflux mechanism.      


2006 ◽  
Vol 72 (5) ◽  
pp. 3498-3503 ◽  
Author(s):  
N. A. Romanova ◽  
P. F. G. Wolffs ◽  
L. Y. Brovko ◽  
M. W. Griffiths

ABSTRACT In this study, potential mechanisms underlying resistance and adaptation to benzalkonium chloride (BC) in Listeria monocytogenes were investigated. Two groups of strains were studied. The first group consisted of strains naturally sensitive to BC which could be adapted to BC. The second group consisted of naturally resistant strains. For all adapted isolates, there was a correlation between the resistance to BC and ethidium bromide, but this was not the case for the naturally resistant isolates. To investigate the role of efflux pumps in adaptation or resistance, reserpine, an efflux pump inhibitor, was added to the strains. Addition of reserpine to the sensitive and adapted strains resulted in a decrease in the MIC for BC, whereas no such decrease was observed for the resistant strains, indicating that efflux pumps played no role in the innate resistance of certain strains of L. monocytogenes to this compound. Two efflux pumps (MdrL and Lde) have been described in L. monocytogenes. Studies showed low and intermediate levels of expression of the genes encoding the efflux pumps for two selected resistant strains, H7764 and H7962, respectively. Adaptation to BC of sensitive isolates of L. monocytogenes resulted in significant increases in expression of mdrl (P < 0.05), but no such increase was observed for lde for two adapted strains of L. monocytogenes, LJH 381 (P = 0.91) and C719 (P = 0.11). This indicates that the efflux pump Mdrl is at least partly responsible for the adaptation to BC.


Author(s):  
Zumaana Rafiq ◽  
Sreevidya Narasimhan ◽  
Magesh Haridoss ◽  
Rosy Vennila ◽  
Rama Vaidyanathan

ABSTRACTObjective: With a rise in multidrug resistant (MDR) bacterial isolates, search for antibiotics or compounds that could act synergistically with themis a significant area of research. Efflux-mediated resistance, in particular, is a great hurdle that needs to be overcome. In an effort to identify suchsynergistic compounds and potential efflux pump inhibitors (EPI), we analyzed the rind of Punica granatum (pomegranate) against MDR clinicalKlebsiella pneumoniae isolates.Methods: Sequential fractionation of P. granatum rind ethanol (PGR) extract was carried out to obtain hexane, butanol and water fractions.Antibacterial activity of the plant extracts was confirmed, and synergistic interaction with antibiotics was determined by the checkerboard assay. Gaschromatography-mass spectrometry (GC-MS) analysis was performed to identify the phytochemical constituents of the hexane extract. To study EPIactivity of the extracts, norfloxacin accumulation assay was carried out.Results: PGR ethanol extract was found to have synergistic activity with ciprofloxacin, levofloxacin, ceftazidime, cefoxitin, meropenem, and gentamicinresulting in fold decrease of minimum inhibitory concentration (MIC) ranging from 2 to 32 fold. The hexane fraction was found to have maximumsynergistic activity resulting in a 32-fold reduction of ciprofloxacin MIC followed by butanol and water fractions. The PGR ethanol extract was alsofound to have efflux inhibition activity by the norfloxacin accumulation assay. Of the sequential fractions, the butanol fraction had maximum effluxinhibition activity.Conclusion: Therefore, our study shows that PGR extract can potentiate the effect of antibiotics on MDR bacteria, and the mode of action is likely tobe due to EPI.Keywords: Punica granatum rind, Pomegranate, Synergy with antibiotics, Multidrug resistant, Klebsiella pneumoniae, Efflux pump inhibition.


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