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Tsilipounidaki K, Gkountinoudis CG, Florou Z, Fthenakis GC, Petinaki E. In Silico Molecular Analysis of Carbapenemase-Negative Carbapenem-Resistant Pseudomonas aeruginosa Strains in Greece. Microorganisms 2024; 12:805. [PMID: 38674749 PMCID: PMC11051870 DOI: 10.3390/microorganisms12040805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 04/02/2024] [Accepted: 04/15/2024] [Indexed: 04/28/2024] Open
Abstract
To date, three carbapenem resistance mechanisms have been identified: carbapenemase released from the pathogen, changes in the expression of the outer membrane OprD porin, and overexpression of the efflux pump MexAB-OprM. Twelve carbapenemase-negative carbapenem-resistant Pseudomonas aeruginosa strains, isolated from patients hospitalized at the University Hospital of Larissa, Central Greece, during 2023, which belonged to various sequence types (STs), were selected and were studied focusing on the characterization of their β-lactamases, on changes to OprD and its regulator MexT proteins, and on alterations to the MexAB-OprM regulator proteins encoded by the mexR, nalC, and nalD genes. Whole genome sequencing analysis revealed the presence of β-lactamase encoding genes, with blaPAO present in all isolates. Additionally, seven different genes of the oxacillinase family (blaOXA-35, blaOXA-50, blaOXA-395, blaOXA-396, blaOXA-486, blaOXA-488, blaOXA-494) were identified, with each strain harboring one to three of these. Regarding the OprD, five strains had truncated structures, at Loop 2, Loop 3, Loop 4, and Loop 9, while the remaining strains carried previously reported amino acid changes. Further, an additional strain had a truncated MexR; whereas, two other strains had totally modified NalC sequences. The active form of MexT, responsible for the downregulation of OprD production, as the intact sequence of the NalD protein, was found in all the strains studied. It is concluded that the truncated OprD, MexR, and NalC proteins, detected in eight strains, probably led to inactive proteins, contributing to carbapenem resistance. However, four strains carried known modifications in OprD, MexR, and NalC, as previously reported in both susceptible and resistant strains, a finding that indicates the complexity of carbapenem resistance in P. aeruginosa.
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Affiliation(s)
- Katerina Tsilipounidaki
- Faculty of Medicine, University of Thessaly, 41500 Larissa, Greece; (K.T.); (C.-G.G.); (Z.F.)
| | | | - Zoi Florou
- Faculty of Medicine, University of Thessaly, 41500 Larissa, Greece; (K.T.); (C.-G.G.); (Z.F.)
| | | | - Efthymia Petinaki
- Faculty of Medicine, University of Thessaly, 41500 Larissa, Greece; (K.T.); (C.-G.G.); (Z.F.)
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Farrington N, Dubey V, Johnson A, Horner I, Stevenson A, Unsworth J, Jimenez-Valverde A, Schwartz J, Das S, Hope W, Darlow CA. Molecular pharmacodynamics of meropenem for nosocomial pneumonia caused by Pseudomonas aeruginosa. mBio 2024; 15:e0316523. [PMID: 38236031 PMCID: PMC10865990 DOI: 10.1128/mbio.03165-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 12/11/2023] [Indexed: 01/19/2024] Open
Abstract
Hospital-acquired pneumonia (HAP) is a leading cause of morbidity and mortality, commonly caused by Pseudomonas aeruginosa. Meropenem is a commonly used therapeutic agent, although emergent resistance occurs during treatment. We used a rabbit HAP infection model to assess the bacterial kill and resistance pharmacodynamics of meropenem. Meropenem 5 mg/kg administered subcutaneously (s.c.) q8h (±amikacin 3.33-5 mg/kg q8h administered intravenously[i.v.]) or meropenem 30 mg/kg s.c. q8h regimens were assessed in a rabbit lung infection model infected with P. aeruginosa, with bacterial quantification and phenotypic/genotypic characterization of emergent resistant isolates. The pharmacokinetic/pharmacodynamic output was fitted to a mathematical model, and human-like regimens were simulated to predict outcomes in a clinical context. Increasing meropenem monotherapy demonstrated a dose-response effect to bacterial kill and an inverted U relationship with emergent resistance. The addition of amikacin to meropenem suppressed the emergence of resistance. A network of porin loss, efflux upregulation, and increased expression of AmpC was identified as the mechanism of this emergent resistance. A bridging simulation using human pharmacokinetics identified meropenem 2 g i.v. q8h as the licensed clinical regimen most likely to suppress resistance. We demonstrate an innovative experimental platform to phenotypically and genotypically characterize bacterial emergent resistance pharmacodynamics in HAP. For meropenem, we have demonstrated the risk of resistance emergence during therapy and identified two mitigating strategies: (i) regimen intensification and (ii) use of combination therapy. This platform will allow pre-clinical assessment of emergent resistance risk during treatment of HAP for other antimicrobials, to allow construction of clinical regimens that mitigate this risk.IMPORTANCEThe emergence of antimicrobial resistance (AMR) during antimicrobial treatment for hospital-acquired pneumonia (HAP) is a well-documented problem (particularly in pneumonia caused by Pseudomonas aeruginosa) that contributes to the wider global antimicrobial resistance crisis. During drug development, regimens are typically determined by their sufficiency to achieve bactericidal effect. Prevention of the emergence of resistance pharmacodynamics is usually not characterized or used to determine the regimen. The innovative experimental platform described here allows characterization of the emergence of AMR during the treatment of HAP and the development of strategies to mitigate this. We have demonstrated this specifically for meropenem-a broad-spectrum antibiotic commonly used to treat HAP. We have characterized the antimicrobial resistance pharmacodynamics of meropenem when used to treat HAP, caused by initially meropenem-susceptible P. aeruginosa, phenotypically and genotypically. We have also shown that intensifying the regimen and using combination therapy are both strategies that can both treat HAP and suppress the emergence of resistance.
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Affiliation(s)
- Nicola Farrington
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | - Vineet Dubey
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | - Adam Johnson
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | - Iona Horner
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | - Adam Stevenson
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | - Jennifer Unsworth
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | - Ana Jimenez-Valverde
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | | | - Shampa Das
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | - William Hope
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
| | - Christopher A. Darlow
- Antimicrobial Pharmacodynamics and Therapeutics, Department of Pharmacology, University of Liverpool, Liverpool Health Partners, Liverpool, United Kingdom
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3
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Menon ND, Somanath P, Jossart J, Vijayakumar G, Shetty K, Baswe M, Chatterjee M, Hari MB, Nair S, Kumar VA, Nair BG, Nizet V, Perry JJP, Kumar GB. Comparative molecular profiling of multidrug-resistant Pseudomonas aeruginosa identifies novel mutations in regional clinical isolates from South India. JAC Antimicrob Resist 2024; 6:dlae001. [PMID: 38230352 PMCID: PMC10789591 DOI: 10.1093/jacamr/dlae001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 12/27/2023] [Indexed: 01/18/2024] Open
Abstract
Objectives We sought to analyse the antibiotic susceptibility profiles and molecular epidemiology of MDR clinical Pseudomonas aeruginosa isolates from South India using non-MDR isolates as a reference. Methods We established a comprehensive clinical strain library consisting of 58 isolates collected from patients across the South Indian state of Kerala from March 2017 to July 2019. The strains were subject to antibiotic susceptibility testing, modified carbapenem inactivation method assay for carbapenemase production, PCR sequencing, comparative sequence analysis and quantitative PCR of MDR determinants associated with antibiotic efflux pump systems, fluoroquinolone resistance and carbapenem resistance. We performed in silico modelling of MDR-specific SNPs. Results Of our collection of South Indian P. aeruginosa clinical isolates, 74.1% were MDR and 55.8% were resistant to the entire panel of antibiotics tested. All MDR isolates were resistant to levofloxacin and 93% were resistant to meropenem. We identified seven distinct, MDR-specific mutations in nalD, three of which are novel. mexA was significantly overexpressed in strains that were resistant to the entire test antibiotic panel while gyrA and gyrB were overexpressed in MDR isolates. Mutations in fluoroquinolone determinants were significantly associated with MDR phenotype and a novel GyrA Y100C substitution was observed. Carbapenem resistance in MDR isolates was associated with loss-of-function mutations in oprD and high prevalence of NDM (blaNDM-1) within our sample. Conclusions This study provides insight into MDR mechanisms adopted by P. aeruginosa clinical isolates, which may guide the potential development of therapeutic regimens to improve clinical outcomes.
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Affiliation(s)
- Nitasha D Menon
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
| | - Priyanka Somanath
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
| | - Jennifer Jossart
- Department of Molecular Diagnostics and Experimental Therapeutics, City of Hope, Duarte, CA, USA
| | - Gayathri Vijayakumar
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
| | - Kavya Shetty
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
| | - Manasi Baswe
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
| | - Meghna Chatterjee
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
| | - Malavika B Hari
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
| | - Samitha Nair
- Department of Microbiology, DDRC SRL Diagnostic Private Limited, Trivandrum, Kerala, India
| | - V Anil Kumar
- Department of Microbiology, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham, Kochi, Kerala, India
| | - Bipin G Nair
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
| | - Victor Nizet
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA, USA
- Department of Pediatrics, University of California, San Diego, La Jolla, CA, USA
| | - J Jefferson P Perry
- Department of Molecular Diagnostics and Experimental Therapeutics, City of Hope, Duarte, CA, USA
| | - Geetha B Kumar
- School of Biotechnology, Amrita Vishwa Vidyapeetham, Amritapuri, Kerala, India
- Antimicrobial Resistance, Tata Institute for Genetics and Society (TIGS), Bangalore, India
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Hujer AM, Marshall SH, Mack AR, Hujer KM, Bakthavatchalam YD, Umarkar K, Palwe SR, Takalkar S, Joshi PR, Shrivastava R, Periasamy H, Bhagwat SS, Patel MV, Veeraraghavan B, Bonomo RA. Transcending the challenge of evolving resistance mechanisms in Pseudomonas aeruginosa through β-lactam-enhancer-mechanism-based cefepime/zidebactam. mBio 2023; 14:e0111823. [PMID: 37889005 PMCID: PMC10746216 DOI: 10.1128/mbio.01118-23] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 09/14/2023] [Indexed: 10/28/2023] Open
Abstract
Compared to other genera of Gram-negative pathogens, Pseudomonas is adept in acquiring complex non-enzymatic and enzymatic resistance mechanisms thus remaining a challenge to even novel antibiotics including recently developed β-lactam and β-lactamase inhibitor combinations. This study shows that the novel β-lactam enhancer approach enables cefepime/zidebactam to overcome both non-enzymatic and enzymatic resistance mechanisms associated with a challenging panel of P. aeruginosa. This study highlights that the β-lactam enhancer mechanism is a promising alternative to the conventional β-lactam/β-lactamase inhibitor approach in combating ever-evolving MDR P. aeruginosa.
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Affiliation(s)
- Andrea M. Hujer
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, Cleveland, Ohio, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Steven H. Marshall
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, Cleveland, Ohio, USA
| | - Andrew R. Mack
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, Cleveland, Ohio, USA
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Kristine M. Hujer
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, Cleveland, Ohio, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | | | - Kushal Umarkar
- Wockhardt Research Centre, Aurangabad, Maharashtra, India
| | | | | | | | | | | | | | | | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu, India
| | - Robert A. Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs, Cleveland, Ohio, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Departments of Pharmacology, Biochemistry, and Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, and the CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, Ohio, USA
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Canè C, Casciaro B, Di Somma A, Loffredo MR, Puglisi E, Battaglia G, Mellini M, Cappiello F, Rampioni G, Leoni L, Amoresano A, Duilio A, Mangoni ML. The antimicrobial peptide Esc(1-21)-1c increases susceptibility of Pseudomonas aeruginosa to conventional antibiotics by decreasing the expression of the MexAB-OprM efflux pump. Front Chem 2023; 11:1271153. [PMID: 37942400 PMCID: PMC10628714 DOI: 10.3389/fchem.2023.1271153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 10/09/2023] [Indexed: 11/10/2023] Open
Abstract
Introduction: The increase in bacterial strains resistant to conventional antibiotics is an alarming problem for human health and could lead to pandemics in the future. Among bacterial pathogens responsible for a large variety of severe infections there is Pseudomonas aeruginosa. Therefore, there is an urgent need for new molecules with antimicrobial activity or that can act as adjuvants of antibiotics already in use. In this scenario, antimicrobial peptides (AMPs) hold great promise. Recently, we characterized a frog-skin AMP derived from esculentin-1a, namely Esc(1-21)-1c, endowed with antipseudomonal activity without being cytotoxic to human cells. Methods: The combinatorial effect of the peptide and antibiotics was investigated through the checkerboard assay, differential proteomic and transcriptional analysis. Results: Here, we found that Esc(1-21)-1c can synergistically inhibit the growth of P. aeruginosa cells with three different antibiotics, including tetracycline. We therefore investigated the underlying mechanism implemented by the peptide using a differential proteomic approach. The data revealed a significant decrease in the production of three proteins belonging to the MexAB-OprM efflux pump upon treatment with sub-inhibitory concentration of Esc(1-21)-1c. Down-regulation of these proteins was confirmed by transcriptional analysis and direct measurement of their relative levels in bacterial cells by tandem mass spectrometry analysis in multiple reaction monitoring scan mode. Conclusion: These evidences suggest that treatment with Esc(1-21)-1c in combination with antibiotics would increase the intracellular drug content making bacteria more susceptible to the antibiotic. Overall, these results highlight the importance of characterizing new molecules able to synergize with conventional antibiotics, paving the way for the development of alternative therapeutic strategies based on AMP/antibiotic formulations to counteract the emergence of resistant bacterial strains and increase the use of "old" antibiotics in medical practice.
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Affiliation(s)
- Carolina Canè
- Department of Chemical Sciences, University of Naples “Federico II”, Naples, Italy
| | - Bruno Casciaro
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Angela Di Somma
- Department of Chemical Sciences, University of Naples “Federico II”, Naples, Italy
- CEINGE Biotecnologie Avanzate, Naples, Italy
| | - Maria Rosa Loffredo
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Elena Puglisi
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Gennaro Battaglia
- Department of Chemical Sciences, University of Naples “Federico II”, Naples, Italy
| | - Marta Mellini
- Department of Science, University “Roma Tre”, Rome, Italy
| | - Floriana Cappiello
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
| | - Giordano Rampioni
- Department of Science, University “Roma Tre”, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Livia Leoni
- Department of Science, University “Roma Tre”, Rome, Italy
| | - Angela Amoresano
- Department of Chemical Sciences, University of Naples “Federico II”, Naples, Italy
- National Institute of Biostructure and Biosystems (INBB), Rome, Italy
| | - Angela Duilio
- Department of Chemical Sciences, University of Naples “Federico II”, Naples, Italy
- National Institute of Biostructure and Biosystems (INBB), Rome, Italy
| | - Maria Luisa Mangoni
- Laboratory Affiliated to Pasteur Italia-Fondazione Cenci Bolognetti, Department of Biochemical Sciences, Sapienza University of Rome, Rome, Italy
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Avakh A, Grant GD, Cheesman MJ, Kalkundri T, Hall S. The Art of War with Pseudomonas aeruginosa: Targeting Mex Efflux Pumps Directly to Strategically Enhance Antipseudomonal Drug Efficacy. Antibiotics (Basel) 2023; 12:1304. [PMID: 37627724 PMCID: PMC10451789 DOI: 10.3390/antibiotics12081304] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 07/26/2023] [Accepted: 08/07/2023] [Indexed: 08/27/2023] Open
Abstract
Pseudomonas aeruginosa (P. aeruginosa) poses a grave clinical challenge due to its multidrug resistance (MDR) phenotype, leading to severe and life-threatening infections. This bacterium exhibits both intrinsic resistance to various antipseudomonal agents and acquired resistance against nearly all available antibiotics, contributing to its MDR phenotype. Multiple mechanisms, including enzyme production, loss of outer membrane proteins, target mutations, and multidrug efflux systems, contribute to its antimicrobial resistance. The clinical importance of addressing MDR in P. aeruginosa is paramount, and one pivotal determinant is the resistance-nodulation-division (RND) family of drug/proton antiporters, notably the Mex efflux pumps. These pumps function as crucial defenders, reinforcing the emergence of extensively drug-resistant (XDR) and pandrug-resistant (PDR) strains, which underscores the urgency of the situation. Overcoming this challenge necessitates the exploration and development of potent efflux pump inhibitors (EPIs) to restore the efficacy of existing antipseudomonal drugs. By effectively countering or bypassing efflux activities, EPIs hold tremendous potential for restoring the antibacterial activity against P. aeruginosa and other Gram-negative pathogens. This review focuses on concurrent MDR, highlighting the clinical significance of efflux pumps, particularly the Mex efflux pumps, in driving MDR. It explores promising EPIs and delves into the structural characteristics of the MexB subunit and its substrate binding sites.
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Affiliation(s)
| | | | | | | | - Susan Hall
- School of Pharmacy and Medical Sciences, Griffith University, Gold Coast, QLD 4222, Australia; (A.A.); (G.D.G.); (M.J.C.); (T.K.)
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Babouee Flury B, Bösch A, Gisler V, Egli A, Seiffert SN, Nolte O, Findlay J. Multifactorial resistance mechanisms associated with resistance to ceftazidime-avibactam in clinical Pseudomonas aeruginosa isolates from Switzerland. Front Cell Infect Microbiol 2023; 13:1098944. [PMID: 37180441 PMCID: PMC10166991 DOI: 10.3389/fcimb.2023.1098944] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Accepted: 04/05/2023] [Indexed: 05/16/2023] Open
Abstract
Background Increasing reports of multidrug resistance (MDR) in clinical Pseudomonas aeruginosa have led to a necessity for new antimicrobials. Ceftazidime-avibactam (CZA) is indicated for use against MDR P. aeruginosa across a broad range of infection types and particularly those that are carbapenem resistant. This study sought to determine the molecular mechanisms of CZA and imipenem (IPM)-resistance in clinical P. aeruginosa isolates obtained from Swiss hospitals. Methods Clinical P. aeruginosa isolates were obtained from inpatients in three hospitals in Switzerland. Susceptibility was determined by either antibiotic disc testing or broth microdilution according to EUCAST methodology. AmpC activity was determined using cloxacillin and efflux activity was determined using phenylalanine-arginine β-naphthylamide, in agar plates. Whole Genome Sequencing was performed on 18 clinical isolates. Sequence types (STs) and resistance genes were ascertained using the Centre for Genomic Epidemiology platform. Genes of interest were extracted from sequenced isolates and compared to reference strain P. aeruginosa PAO1. Results Sixteen different STs were identified amongst the 18 isolates in this study indicating a high degree of genomic diversity. No carbapenemases were detected but one isolate did harbor the ESBL bla PER-1. Eight isolates were CZA-resistant with MICs ranging from 16-64 mg/L, and the remaining ten isolates had either low/wildtype MICs (n=6; 1-2 mg/L) or elevated, but still susceptible, MICs (n=4; 4-8 mg/L). Ten isolates were IPM-resistant, seven of which had mutations resulting in truncations of OprD, and the remaining nine IPM-susceptible isolates had intact oprD genes. Within CZA-R isolates, and those with reduced susceptibility, mutations resulting in ampC derepression, OprD loss, mexAB overexpression and ESBL (bla PER-1) carriage were observed in various combinations and one harbored a truncation of the PBP4 dacB gene. Within the six isolates with wildtype-resistance levels, five had no mutations that would affect any antimicrobial resistance (AMR) genes of interest when compared to PAO1. Conclusion This preliminary study highlights that CZA-resistance in P. aeruginosa is multifactorial and could be caused by the interplay between different resistance mechanisms including ESBL carriage, increased efflux, loss of permeability and derepression of its intrinsic ampC.
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Affiliation(s)
- Baharak Babouee Flury
- Medical Research Center, Kantonspital St. Gallen, St. Gallen, Switzerland
- Division of Infectious Diseases and Hospital Epidemiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Anja Bösch
- Medical Research Center, Kantonspital St. Gallen, St. Gallen, Switzerland
- Division of Infectious Diseases and Hospital Epidemiology, Kantonsspital St. Gallen, St. Gallen, Switzerland
| | - Valentin Gisler
- Clinic of Infectious Diseases and Hospital Hygiene, Kantonsspital Aarau, Aarau, Switzerland
- Department of Microbiology, Institute for Laboratory Medicine, Kantonsspital Aarau, Aarau, Switzerland
| | - Adrian Egli
- Institute of Medical Microbiology, University of Zurich, Zurich, Switzerland
| | - Salome N. Seiffert
- Division of Human Microbiology, Centre for Laboratory Medicine, St. Gallen, Switzerland
| | - Oliver Nolte
- Division of Human Microbiology, Centre for Laboratory Medicine, St. Gallen, Switzerland
| | - Jacqueline Findlay
- Medical and Molecular Microbiology, Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
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8
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Moore-Machacek A, Gloe A, O'Leary N, Reen FJ. Efflux, Signaling and Warfare in a Polymicrobial World. Antibiotics (Basel) 2023; 12:antibiotics12040731. [PMID: 37107093 PMCID: PMC10135244 DOI: 10.3390/antibiotics12040731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/30/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
The discovery void of antimicrobial development has occurred at a time when the world has seen a rapid emergence and spread of antimicrobial resistance, the 'perfect storm' as it has often been described. While the discovery and development of new antibiotics has continued in the research sphere, the pipeline to clinic has largely been fed by derivatives of existing classes of antibiotics, each prone to pre-existing resistance mechanisms. A novel approach to infection management has come from the ecological perspective whereby microbial networks and evolved communities already possess small molecular capabilities for pathogen control. The spatiotemporal nature of microbial interactions is such that mutualism and parasitism are often two ends of the same stick. Small molecule efflux inhibitors can directly target antibiotic efflux, a primary resistance mechanism adopted by many species of bacteria and fungi. However, a much broader anti-infective capability resides within the action of these inhibitors, borne from the role of efflux in key physiological and virulence processes, including biofilm formation, toxin efflux, and stress management. Understanding how these behaviors manifest within complex polymicrobial communities is key to unlocking the full potential of the advanced repertoires of efflux inhibitors.
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Affiliation(s)
| | - Antje Gloe
- School of Microbiology, University College Cork, T12 K8AF Cork, Ireland
- Institute for Pharmaceutical Microbiology, University of Bonn, D-53113 Bonn, Germany
| | - Niall O'Leary
- School of Microbiology, University College Cork, T12 K8AF Cork, Ireland
| | - F Jerry Reen
- School of Microbiology, University College Cork, T12 K8AF Cork, Ireland
- Synthesis and Solid-State Pharmaceutical Centre, University College Cork, T12 K8AF Cork, Ireland
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9
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Hammoudi Halat D, Ayoub Moubareck C. The Intriguing Carbapenemases of Pseudomonas aeruginosa: Current Status, Genetic Profile, and Global Epidemiology. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2022; 95:507-515. [PMID: 36568831 PMCID: PMC9765337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Worldwide, Pseudomonas aeruginosa remains a leading nosocomial pathogen that is difficult to treat and constitutes a challenging menace to healthcare systems. P. aeruginosa shows increased and alarming resistance to carbapenems, long acknowledged as last-resort antibiotics for treatment of resistant infections. Varied and recalcitrant pathways of resistance to carbapenems can simultaneously occur in P. aeruginosa, including the production of carbapenemases, broadest spectrum types of β-lactamases that hydrolyze virtually almost all β-lactams, including carbapenems. The organism can produce chromosomal, plasmid-encoded, and integron- or transposon-mediated carbapenemases from different molecular classes. These include Ambler class A (KPC and some types of GES enzymes), class B (different metallo-β-lactamases such as IMP, VIM, and NDM), and class D (oxacillinases with carbapenem-hydrolyzing capacity like OXA-198) enzymes. Additionally, derepression of chromosomal AmpC cephalosporinases in P. aeruginosa contributes to carbapenem resistance in the presence of other concomitant mechanisms such as impermeability or efflux overexpression. Epidemiologic and molecular evidence of carbapenemases in P. aeruginosa has been long accumulating, and reports of their existence in different geographical areas of the world currently exist. Such reports are continuously being updated and reveal emerging varieties of carbapenemases and/or new genetic environments. This review summarizes carbapenemases of importance in P. aeruginosa, highlights their genetic profile, and presents current knowledge about their global epidemiology.
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Affiliation(s)
- Dalal Hammoudi Halat
- Department of Pharmaceutical Sciences, School of
Pharmacy, Lebanese International University, Beirut and Bekaa Campuses,
Lebanon,To whom all correspondence should be addressed:
Dr. Dalal Hammoudi Halat, Lebanese International University, School of Pharmacy,
West Bekaa, Lebanon; ; ORCID:
https://www.orcid.org/0000-0001-6907-4110
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Lorusso AB, Carrara JA, Barroso CDN, Tuon FF, Faoro H. Role of Efflux Pumps on Antimicrobial Resistance in Pseudomonas aeruginosa. Int J Mol Sci 2022; 23:15779. [PMID: 36555423 PMCID: PMC9779380 DOI: 10.3390/ijms232415779] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 12/15/2022] Open
Abstract
Antimicrobial resistance is an old and silent pandemic. Resistant organisms emerge in parallel with new antibiotics, leading to a major global public health crisis over time. Antibiotic resistance may be due to different mechanisms and against different classes of drugs. These mechanisms are usually found in the same organism, giving rise to multidrug-resistant (MDR) and extensively drug-resistant (XDR) bacteria. One resistance mechanism that is closely associated with the emergence of MDR and XDR bacteria is the efflux of drugs since the same pump can transport different classes of drugs. In Gram-negative bacteria, efflux pumps are present in two configurations: a transmembrane protein anchored in the inner membrane and a complex formed by three proteins. The tripartite complex has a transmembrane protein present in the inner membrane, a periplasmic protein, and a porin associated with the outer membrane. In Pseudomonas aeruginosa, one of the main pathogens associated with respiratory tract infections, four main sets of efflux pumps have been associated with antibiotic resistance: MexAB-OprM, MexXY, MexCD-OprJ, and MexEF-OprN. In this review, the function, structure, and regulation of these efflux pumps in P. aeruginosa and their actions as resistance mechanisms are discussed. Finally, a brief discussion on the potential of efflux pumps in P. aeruginosa as a target for new drugs is presented.
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Affiliation(s)
- Andre Bittencourt Lorusso
- Laboratory for Applied Science and Technology in Health, Carlos Chagas Institute, Fiocruz, Curitiba 81350-010, Brazil
- School of Medicine and Life Sciences, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, Brazil
| | - João Antônio Carrara
- Laboratory for Applied Science and Technology in Health, Carlos Chagas Institute, Fiocruz, Curitiba 81350-010, Brazil
| | | | - Felipe Francisco Tuon
- Laboratory of Emerging Infectious Diseases, Pontifícia Universidade Católica do Paraná, Curitiba 80215-901, Brazil
| | - Helisson Faoro
- Laboratory for Applied Science and Technology in Health, Carlos Chagas Institute, Fiocruz, Curitiba 81350-010, Brazil
- CHU de Quebec Research Center, Department of Microbiology, Infectious Disease and Immunology, University Laval, Quebec, QC G1V 0A6, Canada
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New Variants of Pseudomonas aeruginosa High-Risk Clone ST233 Associated with an Outbreak in a Mexican Paediatric Hospital. Microorganisms 2022; 10:microorganisms10081533. [PMID: 36013951 PMCID: PMC9414371 DOI: 10.3390/microorganisms10081533] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 07/23/2022] [Accepted: 07/23/2022] [Indexed: 02/01/2023] Open
Abstract
Recent multidrug resistance in Pseudomonas aeruginosa has favoured the adaptation and dissemination of worldwide high-risk strains. In June 2018, 15 P. aeruginosa strains isolated from patients and a contaminated multi-dose meropenem vial were characterized to assess their association to an outbreak in a Mexican paediatric hospital. The strains were characterized by antibiotic susceptibility profiling, virulence factors’ production, and biofilm formation. The clonal relationship among isolates was determined with pulse-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST) sequencing. Repressor genes for the MexAB-OprM efflux pump were sequenced for haplotype identification. Of the strains, 60% were profiled as extensively drug-resistant (XDR), 33% as multidrug-resistant (MDR), and 6.6% were classified as sensitive (S). All strains presented intermediate resistance to colistin, and 80% were sensitive to aztreonam. Pyoverdine was the most produced virulence factor. The PFGE technique was performed for the identification of the outbreak, revealing eight strains with the same electrophoretic pattern. ST235 and ten new sequence types (STs) were identified, all closely related to ST233. ST3241 predominated in 26.66% of the strains. Twenty-five synonymous and seventeen nonsynonymous substitutions were identified in the regulatory genes of the MexAB-OprM efflux pump, and nalC was the most variable gene. Six different haplotypes were identified. Strains from the outbreak were metallo-β-lactamases and phylogenetically related to the high-risk clone ST233.
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