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Kherroubi L, Bacon J, Rahman KM. Navigating fluoroquinolone resistance in Gram-negative bacteria: a comprehensive evaluation. JAC Antimicrob Resist 2024; 6:dlae127. [PMID: 39144447 PMCID: PMC11323783 DOI: 10.1093/jacamr/dlae127] [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: 10/26/2023] [Accepted: 07/04/2024] [Indexed: 08/16/2024] Open
Abstract
Since the introduction of quinolone and fluoroquinolone antibiotics to treat bacterial infections in the 1960s, there has been a pronounced increase in the number of bacterial species that have developed resistance to fluoroquinolone treatment. In 2017, the World Health Organization established a priority list of the most critical Gram-negative resistant pathogens. These included Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli. In the last three decades, investigations into the mechanisms of fluoroquinolone resistance have revealed that mutations in the target enzymes of fluoroquinolones, DNA gyrase or topoisomerase IV, are the most prevalent mechanism conferring high levels of resistance. Alterations to porins and efflux pumps that facilitate fluoroquinolone permeation and extrusion across the bacterial cell membrane also contribute to the development of resistance. However, there is a growing observation of novel mutants with newer generations of fluoroquinolones, highlighting the need for novel treatments. Currently, steady progress has been made in the development of novel antimicrobial agents that target DNA gyrase or topoisomerase IV through different avenues than current fluoroquinolones to prevent target-mediated resistance. Therefore, an updated review of the current understanding of fluoroquinolone resistance within the literature is imperative to aid in future investigations.
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Affiliation(s)
- Linda Kherroubi
- School of Cancer and Pharmaceutical Science, King’s College London, London SE1 9NH, UK
| | - Joanna Bacon
- Discovery Group, Vaccine Development and Evaluation Centre, UK Health Security Agency, Porton Down, Salisbury SP4 0JG, UK
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Okumura K, Kaido M, Muratani T, Yamasaki E, Akai Y, Kurazono H, Yamamoto S. Multi-drug resistance pattern and genome-wide SNP detection in levofloxacin-resistant uropathogenic Escherichia coli strains. Int J Urol 2024; 31:295-300. [PMID: 38041251 DOI: 10.1111/iju.15348] [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: 07/27/2023] [Accepted: 11/06/2023] [Indexed: 12/03/2023]
Abstract
OBJECTIVES Antibiotic treatment is extremely stressful for bacteria and has profound effects on their viability. Such administration induces physiological changes in bacterial cells, with considerable impact on their genome structure that induces mutations throughout the entire genome. This study investigated drug resistance profiles and structural changes in the entire genome of uropathogenic Escherichia coli (UPEC) strains isolated from six adapted clones that had evolved under laboratory conditions. METHODS Eight UPEC strains, including two parental strains and six adapted clones, with different fluoroquinolone resistance levels originally isolated from two patients were used. The minimum inhibitory concentration (MIC) of 28 different antibiotics including levofloxacin was determined for each of the eight strains. In addition, the effects of mutations acquired with increased drug resistance in the levofloxacin-resistant strains on expression of genes implicated to be involved in drug resistance were examined. RESULTS Of the eight UPEC strains used to test the MIC of 28 different antibiotics, two highly fluoroquinolone-resistant strains showed increased MIC in association with many of the antibiotics. As drug resistance increased, some genes acquired mutations, including the transcriptional regulator acrR and DNA-binding transcriptional repressor marR. Two strain groups with genetically different backgrounds (GUC9 and GFCS1) commonly acquired mutations in acrR and marR. Notably, acquired mutations related to efflux pump upregulation also contributed to increases in MIC for various antibiotics other than fluoroquinolone. CONCLUSIONS The present results obtained using strains with artificially acquired drug resistance clarify the underlying mechanism of resistance to fluoroquinolones and other types of antibiotics.
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Affiliation(s)
- Kayo Okumura
- Management Department of Biosafety, Laboratory Animal, and Pathogen Bank, National Institute of Infectious Diseases, Higashimurayama, Tokyo, Japan
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Masako Kaido
- Scientific Affairs, Medical & Scientific Affairs, Sysmex Corporation, Kobe, Hyogo, Japan
| | | | - Eiki Yamasaki
- Diagnostic Center for Animal Health and Food Safety, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Yasumasa Akai
- Regulatory Affairs & Quality Assurance, Sysmex Corporation, Kobe, Hyogo, Japan
| | - Hisao Kurazono
- Department of Veterinary Medicine, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Shingo Yamamoto
- Department of Urology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
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Asghar A, Khalid A, Baqar Z, Hussain N, Saleem MZ, Sairash, Rizwan K. An insights into emerging trends to control the threats of antimicrobial resistance (AMR): an address to public health risks. Arch Microbiol 2024; 206:72. [PMID: 38252323 DOI: 10.1007/s00203-023-03800-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 12/07/2023] [Accepted: 12/15/2023] [Indexed: 01/23/2024]
Abstract
Antimicrobial agents are used to treat microbial ailments, but increased use of antibiotics and exposure to infections in healthcare facilities and hospitals as well as the excessive and inappropriate use of antibiotics at the society level lead to the emergence of multidrug-resistant (MDR) bacteria. Antimicrobial resistance (AMR) is considered a public health concern and has rendered the treatment of different infections more challenging. The bacterial strains develop resistance against antimicrobial agents by limiting intracellular drug accumulation (increasing efflux or decreasing influx of antibiotics), modification and inactivation of drugs and its targets, enzymatic inhibition, and biofilm formation. However, the driving factors of AMR include the sociocultural and economic circumstances of a country, the use of falsified and substandard medicines, the use of antibiotics in farm animals, and food processing technologies. These factors make AMR one of the major menaces faced by mankind. In order to promote reciprocal learning, this article summarizes the current AMR situation in Pakistan and how it interacts with the health issues related to the COVID-19 pandemic. The COVID-19 pandemic aids in illuminating the possible long-term impacts of AMR, which are less immediate but not less severe since their measures and effects are equivalent. Impact on other sectors, including the health industry, the economy, and trade are also discussed. We conclude by summarizing the several approaches that could be used to address this issue.
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Affiliation(s)
- Ayesha Asghar
- School of Biochemistry and Biotechnology, University of the Punjab, Quaid-E-Azam Campus, Lahore, Pakistan
| | - Aneeza Khalid
- School of Biochemistry and Biotechnology, University of the Punjab, Quaid-E-Azam Campus, Lahore, Pakistan
| | - Zulqarnain Baqar
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon, Hong Kong, China
| | - Nazim Hussain
- Centre for Applied Molecular Biology (CAMB), University of the Punjab, Quaid-E-Azam Campus, Lahore, Pakistan.
| | - Muhammad Zafar Saleem
- Centre for Applied Molecular Biology (CAMB), University of the Punjab, Quaid-E-Azam Campus, Lahore, Pakistan
| | - Sairash
- Faculty of Medicine, Chulalongkorn University, Bangkok, 10330, Thailand
| | - Komal Rizwan
- Department of Chemistry, University of Sahiwal, Sahiwal, 57000, Pakistan.
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Yu Z, Shi X, Wang Z. Structures and Efflux Mechanisms of the AcrAB-TolC Pump. Subcell Biochem 2024; 104:1-16. [PMID: 38963480 DOI: 10.1007/978-3-031-58843-3_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/05/2024]
Abstract
The global emergence of multidrug resistance (MDR) in gram-negative bacteria has become a matter of worldwide concern. MDR in these pathogens is closely linked to the overexpression of certain efflux pumps, particularly the resistance-nodulation-cell division (RND) efflux pumps. Inhibition of these pumps presents an attractive and promising strategy to combat antibiotic resistance, as the efflux pump inhibitors can effectively restore the potency of existing antibiotics. AcrAB-TolC is one well-studied RND efflux pump, which transports a variety of substrates, therefore providing resistance to a broad spectrum of antibiotics. To develop effective pump inhibitors, a comprehensive understanding of the structural aspect of the AcrAB-TolC efflux pump is imperative. Previous studies on this pump's structure have been limited to individual components or in vitro determination of fully assembled pumps. Recent advancements in cellular cryo-electron tomography (cryo-ET) have provided novel insights into this pump's assembly and functional mechanism within its native cell membrane environment. Here, we present a summary of the structural data regarding the AcrAB-TolC efflux pump, shedding light on its assembly pathway and operational mechanism.
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Affiliation(s)
- Zhili Yu
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - Xiaodong Shi
- Jiangsu Province Key Laboratory of Anesthesiology and Jiangsu Province Key Laboratory of Anesthesia and Analgesia Application, Xuzhou Medical University, Xuzhou, Jiangsu, China
| | - Zhao Wang
- Verna and Marrs McLean Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA.
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX, USA.
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Sodium Malonate Inhibits the AcrAB-TolC Multidrug Efflux Pump of Escherichia coli and Increases Antibiotic Efficacy. Pathogens 2022; 11:pathogens11121409. [PMID: 36558743 PMCID: PMC9781404 DOI: 10.3390/pathogens11121409] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/11/2022] [Accepted: 11/21/2022] [Indexed: 11/25/2022] Open
Abstract
There is an urgent need to find novel treatments for combating multidrug-resistant bacteria. Multidrug efflux pumps that expel antibiotics out of cells are major contributors to this problem. Therefore, using efflux pump inhibitors (EPIs) is a promising strategy to increase antibiotic efficacy. However, there are no EPIs currently approved for clinical use especially because of their toxicity. This study investigates sodium malonate, a natural, non-hazardous, small molecule, for its use as a novel EPI of AcrAB-TolC, the main multidrug efflux pump of the Enterobacteriaceae family. Using ethidium bromide accumulation experiments, we found that 25 mM sodium malonate inhibited efflux by the AcrAB-TolC and other MDR pumps of Escherichia coli to a similar degree than 50 μΜ phenylalanine-arginine-β-naphthylamide, a well-known EPI. Using minimum inhibitory concentration assays and molecular docking to study AcrB-ligand interactions, we found that sodium malonate increased the efficacy of ethidium bromide and the antibiotics minocycline, chloramphenicol, and ciprofloxacin, possibly via binding to multiple AcrB locations, including the AcrB proximal binding pocket. In conclusion, sodium malonate is a newly discovered EPI that increases antibiotic efficacy. Our findings support the development of malonic acid/sodium malonate and its derivatives as promising EPIs for augmenting antibiotic efficacy when treating multidrug-resistant bacterial infections.
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Mitra S, Sultana SA, Prova SR, Uddin TM, Islam F, Das R, Nainu F, Sartini S, Chidambaram K, Alhumaydhi FA, Emran TB, Simal-Gandara J. Investigating forthcoming strategies to tackle deadly superbugs: current status and future vision. Expert Rev Anti Infect Ther 2022; 20:1309-1332. [PMID: 36069241 DOI: 10.1080/14787210.2022.2122442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
INTRODUCTION Superbugs are microorganisms that cause disease and have increased resistance to the treatments typically used against infections. Recently, antibiotic resistance development has been more rapid than the pace at which antibiotics are manufactured, leading to refractory infections of pathogenic bacteria. Scientists are concerned that a particularly virulent and lethal "superbug" will one day join the ranks of existing bacteria that cause incurable diseases, resulting in a global health disaster on the scale of the Black Death. AREAS COVERED Therefore, this study highlights the current developments in the management of antibiotic-resistant bacteria and recommends strategies for further regulating antibiotic-resistant microorganisms associated with the healthcare system. This review also addresses the origins, prevalence, and pathogenicity of superbugs, and the design of antibacterial against these growing multidrug-resistant organisms from a medical perspective. EXPERT OPINION It is recommended that antimicrobial resistance (AMR) should be addressed by limiting human-to-human transmission of resistant strains, lowering the use of broad-spectrum antibiotics, and developing novel antimicrobials. Using the risk-factor domains framework from this study would assure that not only clinical but also community and hospital-specific factors are covered, lowering the chance of confounders. Extensive subjective research is necessary to fully understand the underlying factors and uncover previously unexplored areas.
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Affiliation(s)
- Saikat Mitra
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Sifat Ara Sultana
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Shajuthi Rahman Prova
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Tanvir Mahtab Uddin
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Fahadul Islam
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Dhaka 1207, Bangladesh
| | - Rajib Das
- Department of Pharmacy, Faculty of Pharmacy, University of Dhaka, Dhaka 1000, Bangladesh
| | - Firzan Nainu
- Faculty of Pharmacy, Hasanuddin University, Makassar, South Sulawesi 90245, Indonesia
| | - Sartini Sartini
- Department of Pharmaceutical Science and Technology, Faculty of Pharmacy, Hasanuddin University, Makassar 90245, Indonesia
| | - Kumarappan Chidambaram
- Department of Pharmacology and Toxicology, College of Pharmacy, King Khalid University, Abha 62529, Saudi Arabia
| | - Fahad A Alhumaydhi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 52571, Saudi Arabia
| | - Talha Bin Emran
- Department of Pharmacy, Faculty of Allied Health Sciences, Daffodil International University, Dhaka 1207, Bangladesh.,Department of Pharmacy, BGC Trust University Bangladesh, Chittagong 4381, Bangladesh
| | - Jesus Simal-Gandara
- Nutrition and Bromatology Group, Department of Analytical and Food Chemistry, Faculty of Food Science and Technology, University of Vigo - Ourense Campus, E32004 Ourense, Spain
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Structural basis for inhibition of the drug efflux pump NorA from Staphylococcus aureus. Nat Chem Biol 2022; 18:706-712. [PMID: 35361990 PMCID: PMC9246859 DOI: 10.1038/s41589-022-00994-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 02/08/2022] [Indexed: 11/08/2022]
Abstract
Membrane protein efflux pumps confer antibiotic resistance by extruding structurally distinct compounds and lowering their intracellular concentration. Yet, there are no clinically approved drugs to inhibit efflux pumps, which would potentiate the efficacy of existing antibiotics rendered ineffective by drug efflux. Here we identified synthetic antigen-binding fragments (Fabs) that inhibit the quinolone transporter NorA from methicillin-resistant Staphylococcus aureus (MRSA). Structures of two NorA-Fab complexes determined using cryo-electron microscopy reveal a Fab loop deeply inserted in the substrate-binding pocket of NorA. An arginine residue on this loop interacts with two neighboring aspartate and glutamate residues essential for NorA-mediated antibiotic resistance in MRSA. Peptide mimics of the Fab loop inhibit NorA with submicromolar potency and ablate MRSA growth in combination with the antibiotic norfloxacin. These findings establish a class of peptide inhibitors that block antibiotic efflux in MRSA by targeting indispensable residues in NorA without the need for membrane permeability.
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Gu Y, Huang L, Wu C, Huang J, Hao H, Yuan Z, Cheng G. The Evolution of Fluoroquinolone Resistance in Salmonella under Exposure to Sub-Inhibitory Concentration of Enrofloxacin. Int J Mol Sci 2021; 22:ijms222212218. [PMID: 34830098 PMCID: PMC8619427 DOI: 10.3390/ijms222212218] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 10/25/2021] [Accepted: 11/02/2021] [Indexed: 02/04/2023] Open
Abstract
The evolution of resistance in Salmonella to fluoroquinolones (FQs) under a broad range of sub-inhibitory concentrations (sub-MICs) has not been systematically studied. This study investigated the mechanism of resistance development in Salmonella enterica serovar Enteritidis (S. Enteritidis) under sub-MICs of 1/128×MIC to 1/2×MIC of enrofloxacin (ENR), a widely used veterinary FQ. It was shown that the resistance rate and resistance level of S. Enteritidis varied with the increase in ENR concentration and duration of selection. qRT-PCR results demonstrated that the expression of outer membrane porin (OMP) genes, ompC, ompD and ompF, were down-regulated first to rapidly adapt and develop the resistance of 4×MIC, and as the resistance level increased (≥8×MIC), the up-regulated expression of efflux pump genes, acrB, emrB amd mdfA, along with mutations in quinolone resistance-determining region (QRDR) gradually played a decisive role. Cytohubba analysis based on transcriptomic profiles demonstrated that purB, purC, purD, purF, purH, purK, purL, purM, purN and purT were the hub genes for the FQs resistance. The 'de novo' IMP biosynthetic process, purine ribonucleoside monophosphate biosynthetic process and purine ribonucleotide biosynthetic process were the top three biological processes screened by MCODE. This study first described the dynamics of FQ resistance evolution in Salmonella under a long-term selection of sub-MICs of ENR in vitro. In addition, this work offers greater insight into the transcriptome changes of S. Enteritidis under the selection of ENR and provides a framework for FQs resistance of Salmonella for further studies.
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Affiliation(s)
- Yufeng Gu
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (Y.G.); (L.H.); (C.W.); (J.H.); (H.H.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan 430070, China
| | - Lulu Huang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (Y.G.); (L.H.); (C.W.); (J.H.); (H.H.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan 430070, China
| | - Cuirong Wu
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (Y.G.); (L.H.); (C.W.); (J.H.); (H.H.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan 430070, China
| | - Junhong Huang
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (Y.G.); (L.H.); (C.W.); (J.H.); (H.H.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan 430070, China
| | - Haihong Hao
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (Y.G.); (L.H.); (C.W.); (J.H.); (H.H.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan 430070, China
| | - Zonghui Yuan
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (Y.G.); (L.H.); (C.W.); (J.H.); (H.H.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan 430070, China
| | - Guyue Cheng
- College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, China; (Y.G.); (L.H.); (C.W.); (J.H.); (H.H.); (Z.Y.)
- MOA Laboratory for Risk Assessment of Quality and Safety of Livestock and Poultry Products, Huazhong Agricultural University, Wuhan 430070, China
- Correspondence: ; Tel.: +86-027-8728-7165
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Kotrange H, Najda A, Bains A, Gruszecki R, Chawla P, Tosif MM. Metal and Metal Oxide Nanoparticle as a Novel Antibiotic Carrier for the Direct Delivery of Antibiotics. Int J Mol Sci 2021; 22:ijms22179596. [PMID: 34502504 PMCID: PMC8431128 DOI: 10.3390/ijms22179596] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/31/2021] [Accepted: 08/31/2021] [Indexed: 12/23/2022] Open
Abstract
In addition to the benefits, increasing the constant need for antibiotics has resulted in the development of antibiotic bacterial resistance over time. Antibiotic tolerance mainly evolves in these bacteria through efflux pumps and biofilms. Leading to its modern and profitable uses, emerging nanotechnology is a significant field of research that is considered as the most important scientific breakthrough in recent years. Metal nanoparticles as nanocarriers are currently attracting a lot of interest from scientists, because of their wide range of applications and higher compatibility with bioactive components. As a consequence of their ability to inhibit the growth of bacteria, nanoparticles have been shown to have significant antibacterial, antifungal, antiviral, and antiparasitic efficacy in the battle against antibiotic resistance in microorganisms. As a result, this study covers bacterial tolerance to antibiotics, the antibacterial properties of various metal nanoparticles, their mechanisms, and the use of various metal and metal oxide nanoparticles as novel antibiotic carriers for direct antibiotic delivery.
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Affiliation(s)
- Harshada Kotrange
- Department of Food Technology and Nutrition, Lovely Professional University, Jalandhar 144411, Punjab, India; (H.K.); (M.M.T.)
| | - Agnieszka Najda
- Department of Vegetable Crops and Medicinal Plants, University of Life Sciences in Lublin, Doświadczalna Street, 20-280 Lublin, Poland;
- Correspondence: (A.N.); (P.C.)
| | - Aarti Bains
- Department of Biotechnology, CT Institute of Pharmaceutical Sciences, South Campus, Jalandhar 144020, Punjab, India;
| | - Robert Gruszecki
- Department of Vegetable Crops and Medicinal Plants, University of Life Sciences in Lublin, Doświadczalna Street, 20-280 Lublin, Poland;
| | - Prince Chawla
- Department of Food Technology and Nutrition, Lovely Professional University, Jalandhar 144411, Punjab, India; (H.K.); (M.M.T.)
- Correspondence: (A.N.); (P.C.)
| | - Mansuri M. Tosif
- Department of Food Technology and Nutrition, Lovely Professional University, Jalandhar 144411, Punjab, India; (H.K.); (M.M.T.)
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Seeger J, Michelet R, Kloft C. Quantification of persister formation of Escherichia coli leveraging electronic cell counting and semi-mechanistic pharmacokinetic/pharmacodynamic modelling. J Antimicrob Chemother 2021; 76:2088-2096. [PMID: 33997902 DOI: 10.1093/jac/dkab146] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 04/07/2021] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Persister formation of Escherichia coli under fluoroquinolone exposure causes treatment failure and promotes emergence of resistant strains. Semi-mechanistic pharmacokinetic/pharmacodynamic modelling of data obtained from in vitro infection model experiments comprehensively characterizes exposure-effect relationships, providing mechanistic insights. OBJECTIVES To quantify persister formation of E. coli under levofloxacin exposure and to explain the observed growth-kill behaviour, leveraging electronic cell counting and pharmacokinetic/pharmacodynamic modelling. METHODS Three fluoroquinolone-resistant clinical E. coli isolates were exposed to levofloxacin in static and dynamic in vitro infection model experiments. Complementary to plate counting, bacterial concentrations over time were quantified by electronic cell counting and amalgamated in a semi-mechanistic pharmacokinetic/pharmacodynamic model (1281 bacterial and 394 levofloxacin observations). RESULTS Bacterial regrowth was observed under exposure to clinically relevant dosing regimens in the dynamic in vitro infection model. Electronic cell counting facilitated identification of three bacterial subpopulations: persisters, viable cells and dead cells. Two strain-specific manifestations of the levofloxacin effect were identified: a killing effect, characterized as a sigmoidal Emax model, and an additive increase in persister formation under levofloxacin exposure. Significantly different EC50 values quantitatively discerned levofloxacin potency for two isolates displaying the same MIC value: 8 mg/L [EC50 = 17.2 (95% CI = 12.6-23.8) mg/L and 8.46 (95% CI = 6.86-10.3) mg/L, respectively]. Persister formation was most pronounced for the isolate with the lowest MIC value (2 mg/L). CONCLUSIONS The developed pharmacokinetic/pharmacodynamic model adequately characterized growth-kill behaviour of three E. coli isolates and unveiled strain-specific levofloxacin potencies and persister formation. The mimicked dosing regimens did not eradicate the resistant isolates and enhanced persister formation to a strain-specific extent.
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Affiliation(s)
- Johanna Seeger
- Department of Clinical Pharmacy and Biochemistry, Institute of Pharmacy, Freie Universitaet Berlin, Kelchstr. 31, 12169, Berlin, Germany
| | - Robin Michelet
- Department of Clinical Pharmacy and Biochemistry, Institute of Pharmacy, Freie Universitaet Berlin, Kelchstr. 31, 12169, Berlin, Germany
| | - Charlotte Kloft
- Department of Clinical Pharmacy and Biochemistry, Institute of Pharmacy, Freie Universitaet Berlin, Kelchstr. 31, 12169, Berlin, Germany
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11
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Azargun R, Gholizadeh P, Sadeghi V, Hosainzadegan H, Tarhriz V, Memar MY, Pormohammad A, Eyvazi S. Molecular mechanisms associated with quinolone resistance in Enterobacteriaceae: review and update. Trans R Soc Trop Med Hyg 2021; 114:770-781. [PMID: 32609840 DOI: 10.1093/trstmh/traa041] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 04/09/2020] [Accepted: 05/20/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Quinolones are broad-spectrum antibiotics, which are used for the treatment of different infectious diseases associated with Enterobacteriaceae. During recent decades, the wide use as well as overuse of quinolones against diverse infections has led to the emergence of quinolone-resistant bacterial strains. Herein, we present the development of quinolone antibiotics, their function and also the different quinolone resistance mechanisms in Enterobacteriaceae by reviewing recent literature. METHODS All data were extracted from Google Scholar search engine and PubMed site, using keywords; quinolone resistance, Enterobacteriaceae, plasmid-mediated quinolone resistance, etc. RESULTS AND CONCLUSION The acquisition of resistance to quinolones is a complex and multifactorial process. The main resistance mechanisms consist of one or a combination of target-site gene mutations altering the drug-binding affinity of target enzymes. Other mechanisms of quinolone resistance are overexpression of AcrAB-tolC multidrug-resistant efflux pumps and downexpression of porins as well as plasmid-encoded resistance proteins including Qnr protection proteins, aminoglycoside acetyltransferase (AAC(6')-Ib-cr) and plasmid-encoded active efflux pumps such as OqxAB and QepA. The elucidation of resistance mechanisms will help researchers to explore new drugs against the resistant strains.
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Affiliation(s)
- Robab Azargun
- Department of Microbiology, Faculty of Medicine, Maragheh University of Medical Sciences, Maragheh, Iran
| | - Pourya Gholizadeh
- Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Vahid Sadeghi
- Faculty of Veterinary Medicine, Islamic Azad University, Urmia, Iran
| | - Hasan Hosainzadegan
- Department of Microbiology, Faculty of Medicine, Maragheh University of Medical Sciences, Maragheh, Iran
| | - Vahideh Tarhriz
- Molecular Medicine Research Center, Biomedicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Mohammad Yousef Memar
- Infectious and Tropical Diseases Research Center, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali Pormohammad
- Department of Microbiology, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shirin Eyvazi
- Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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12
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Chang MX, Zhang JF, Sun YH, Li RS, Lin XL, Yang L, Webber MA, Jiang HX. Contribution of Different Mechanisms to Ciprofloxacin Resistance in Salmonella spp. Front Microbiol 2021; 12:663731. [PMID: 34025618 PMCID: PMC8137344 DOI: 10.3389/fmicb.2021.663731] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 04/09/2021] [Indexed: 11/28/2022] Open
Abstract
Development of fluoroquinolone resistance can involve several mechanisms that include chromosomal mutations in genes (gyrAB and parCE) encoding the target bacterial topoisomerase enzymes, increased expression of the AcrAB-TolC efflux system, and acquisition of transmissible quinolone-resistance genes. In this study, 176 Salmonella isolates from animals with a broad range of ciprofloxacin MICs were collected to analyze the contribution of these different mechanisms to different phenotypes. All isolates were classified according to their ciprofloxacin susceptibility pattern into five groups as follows: highly resistant (HR), resistant (R), intermediate (I), reduced susceptibility (RS), and susceptible (S). We found that the ParC T57S substitution was common in strains exhibiting lowest MICs of ciprofloxacin while increased MICs depended on the type of GyrA mutation. The ParC T57S substitution appeared to incur little cost to bacterial fitness on its own. The presence of PMQR genes represented an route for resistance development in the absence of target-site mutations. Switching of the plasmid-mediated quinolone resistance (PMQR) gene location from a plasmid to the chromosome was observed and resulted in decreased ciprofloxacin susceptibility; this also correlated with increased fitness and a stable resistance phenotype. The overexpression of AcrAB-TolC played an important role in isolates with small decreases in susceptibility and expression was upregulated by MarA more often than by RamA. This study increases our understanding of the relative importance of several resistance mechanisms in the development of fluoroquinolone resistance in Salmonella from the food chain.
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Affiliation(s)
- Man-Xia Chang
- Guangdong Key Laboratory of Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
| | - Jin-Fei Zhang
- Guangdong Key Laboratory of Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Yin-Huan Sun
- Guangdong Key Laboratory of Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Rong-Sheng Li
- Guangdong Key Laboratory of Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Xiao-Ling Lin
- Guangdong Key Laboratory of Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Ling Yang
- Guangdong Key Laboratory of Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China
| | - Mark A Webber
- Quadram Institute Bioscience, Norwich Research Park, Norwich, United Kingdom.,Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, United Kingdom
| | - Hong-Xia Jiang
- Guangdong Key Laboratory of Veterinary Drug Development and Safety Evaluation, College of Veterinary Medicine, South China Agricultural University, Guangzhou, China.,Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou, China
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13
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Langevin AM, El Meouche I, Dunlop MJ. Mapping the Role of AcrAB-TolC Efflux Pumps in the Evolution of Antibiotic Resistance Reveals Near-MIC Treatments Facilitate Resistance Acquisition. mSphere 2020; 5:e01056-20. [PMID: 33328350 PMCID: PMC7771234 DOI: 10.1128/msphere.01056-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 11/29/2020] [Indexed: 12/20/2022] Open
Abstract
Antibiotic resistance has become a major public health concern as bacteria evolve to evade drugs, leading to recurring infections and a decrease in antibiotic efficacy. Systematic efforts have revealed mechanisms involved in resistance. Yet, in many cases, how these specific mechanisms accelerate or slow the evolution of resistance remains unclear. Here, we conducted a systematic study of the impact of the AcrAB-TolC efflux pump on the evolution of antibiotic resistance. We mapped how population growth rate and resistance change over time as a function of both the antibiotic concentration and the parent strain's genetic background. We compared the wild-type strain to a strain overexpressing AcrAB-TolC pumps and a strain lacking functional pumps. In all cases, resistance emerged when cultures were treated with chloramphenicol concentrations near the MIC of their respective parent strain. The genetic background of the parent strain also influenced resistance acquisition. The wild-type strain evolved resistance within 24 h through mutations in the acrAB operon and its associated regulators. Meanwhile, the strain overexpressing AcrAB-TolC evolved resistance more slowly than the wild-type strain; this strain achieved resistance in part through point mutations in acrB and the acrAB promoter. Surprisingly, the strain without functional AcrAB-TolC efflux pumps still gained resistance, which it achieved through upregulation of redundant efflux pumps. Overall, our results suggest that treatment conditions just above the MIC pose the largest risk for the evolution of resistance and that AcrAB-TolC efflux pumps impact the pathway by which chloramphenicol resistance is achieved.IMPORTANCE Combatting the rise of antibiotic resistance is a significant challenge. Efflux pumps are an important contributor to drug resistance; they exist across many cell types and can export numerous classes of antibiotics. Cells can regulate pump expression to maintain low intracellular drug concentrations. Here, we explored how resistance emerged depending on the antibiotic concentration, as well as the presence of efflux pumps and their regulators. We found that treatments near antibiotic concentrations that inhibit the parent strain's growth were most likely to promote resistance. While wild-type, pump overexpression, and pump knockout strains were all able to evolve resistance, they differed in the absolute level of resistance evolved, the speed at which they achieved resistance, and the genetic pathways involved. These results indicate that specific treatment regimens may be especially problematic for the evolution of resistance and that the strain background can influence how resistance is achieved.
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Affiliation(s)
- Ariel M Langevin
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
- Biological Design Center, Boston, Massachusetts, USA
| | - Imane El Meouche
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
- Biological Design Center, Boston, Massachusetts, USA
| | - Mary J Dunlop
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, USA
- Biological Design Center, Boston, Massachusetts, USA
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14
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Soares A, Alexandre K, Lamoureux F, Lemée L, Caron F, Pestel-Caron M, Etienne M. Efficacy of a ciprofloxacin/amikacin combination against planktonic and biofilm cultures of susceptible and low-level resistant Pseudomonas aeruginosa. J Antimicrob Chemother 2020; 74:3252-3259. [PMID: 31424553 DOI: 10.1093/jac/dkz355] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/21/2019] [Accepted: 07/17/2019] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND Eradicating bacterial biofilm without mechanical dispersion remains a challenge. Combination therapy has been suggested as a suitable strategy to eradicate biofilm. OBJECTIVES To evaluate the efficacy of a ciprofloxacin/amikacin combination in a model of in vitro Pseudomonas aeruginosa biofilm. METHODS The antibacterial activity of ciprofloxacin and amikacin (alone, in combination and successively) was evaluated by planktonic and biofilm time-kill assays against five P. aeruginosa strains: PAO1, a WT clinical strain and three clinical strains overexpressing the efflux pumps MexAB-OprM (AB), MexXY-OprM (XY) and MexCD-OprJ (CD), respectively. Amikacin MIC was 16 mg/L for XY and ciprofloxacin MIC was 0.5 mg/L for CD. The other strains were fully susceptible to ciprofloxacin and amikacin. The numbers of total and resistant cells were determined. RESULTS In planktonic cultures, regrowth of high-level resistant mutants was observed when CD was exposed to ciprofloxacin alone and XY to amikacin alone. Eradication was obtained with ciprofloxacin or amikacin in the other strains, or with the combination in XY and CD strains. In biofilm, bactericidal reduction after 8 h followed by a mean 4 log10 cfu/mL plateau in all strains and for all regimens was noticed. No regrowth of resistant mutants was observed whatever the antibiotic regimen. The bacterial reduction obtained with a second antibiotic used simultaneously or consecutively was not significant. CONCLUSIONS The ciprofloxacin/amikacin combination prevented the emergence of resistant mutants in low-level resistant strains in planktonic cultures. Biofilm persister cells were not eradicated, either with monotherapy or with the combination.
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Affiliation(s)
- Anaïs Soares
- EA 2656 (GRAM), Normandie Univ, Unirouen, Rouen, France.,Microbiology Department, Rouen University Hospital, Rouen, France
| | - Kévin Alexandre
- EA 2656 (GRAM), Normandie Univ, Unirouen, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
| | - Fabien Lamoureux
- Laboratory of Pharmacology, Toxicology and Pharmacogenetics, Rouen University Hospital, Rouen, France
| | - Ludovic Lemée
- EA 2656 (GRAM), Normandie Univ, Unirouen, Rouen, France.,Microbiology Department, Rouen University Hospital, Rouen, France
| | - François Caron
- EA 2656 (GRAM), Normandie Univ, Unirouen, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
| | - Martine Pestel-Caron
- EA 2656 (GRAM), Normandie Univ, Unirouen, Rouen, France.,Microbiology Department, Rouen University Hospital, Rouen, France
| | - Manuel Etienne
- EA 2656 (GRAM), Normandie Univ, Unirouen, Rouen, France.,Infectious Diseases Department, Rouen University Hospital, Rouen, France
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15
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Yang P, Chen Y, Jiang S, Shen P, Lu X, Xiao Y. Association between the rate of fluoroquinolones-resistant gram-negative bacteria and antibiotic consumption from China based on 145 tertiary hospitals data in 2014. BMC Infect Dis 2020; 20:269. [PMID: 32264851 PMCID: PMC7137221 DOI: 10.1186/s12879-020-04981-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 03/18/2020] [Indexed: 01/06/2023] Open
Abstract
Background The purpose of the study is to discuss the correlation between the resistance rate of gram negative bacteria to fluoroquinolones (FQ) and antibiotic consumption intensity of 145 China tertiary hospitals in 2014. Methods This retrospective study adopted national monitoring data from 2014. Each participating hospital required to report annual consumption of each antibiotic, and the resistance rate of gram negative bacteria to FQ. Then the correlation between antibiotic usage and fluoroquinolones –resistant (FQR) rate was consequently investigated. Results One hundred forty-five hospitals were included in the study, and the median antibiotic consumption intensity was 46.30 (23.93–115.39) defined daily dosages (DDDs) per 100 patient-days. Cephalosporins ranks first in the antibiotics consumption, followed by fluoroquinolones, penicillins, and carbapenems. Fluoroquinolones resistance rate varied from hospital to hospital. The correlation analysis showed significant relationship between the percentage of FQR Escherichia coli and the consumption of FQs (r = 0.308, p<0.01) and levofloxacin (r = 0.252, p<0.01). For FQR Klebsiella pneumoniae, not only FQs (r = 0.291, p<0.01) and levofloxacin (r = 0.260, p<0.01) use but also carbapenems (r = 0.242, p<0.01) and overall antibiotics (r = 0.247, p<0.01) use showed significant correlation. The resistant proportion of FQR Pseudomonas aeruginosa was observed to be correlated with the consumption of all antibiotics (r = 0.260, p<0.01), FQs (r = 0.319, p<0.01) and levofloxacin (r = 0.377, p<0.01). The percentage of levofloxacin-resistant Acinetobacter baumannii was significantly correlated with the consumption of all antibiotics (r = 0.282, p<0.01), third-generation cephalosporins excluding combinations with beta-lactamase inhibitors (r = 0.246, p<0.01), FQs (r = 0.254, p<0.01) and levofloxacin (r = 0.336, p<0.01). However, the correlation of the ciprofloxacin-resistant A. baumannii and the antibiotics consumption was not found. Conclusions A strong correlation was demonstrated between the antibiotic consumption and the rates of FQR gram-negative bacteria. As unreasonable antibiotics usage remains crucial in the proceeding of resistant bacteria selection, our study could greatly promote the avoidance of unnecessary antibiotic usage.
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Affiliation(s)
- Ping Yang
- Department of Pharmacy, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Yunbo Chen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China
| | - Saiping Jiang
- Department of Pharmacy, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Ping Shen
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China
| | - Xiaoyang Lu
- Department of Pharmacy, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Yonghong Xiao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, 79 Qingchun Road, Hangzhou, China.
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16
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Overexpression of RamA, Which Regulates Production of the Multidrug Resistance Efflux Pump AcrAB-TolC, Increases Mutation Rate and Influences Drug Resistance Phenotype. Antimicrob Agents Chemother 2020; 64:AAC.02460-19. [PMID: 31988103 DOI: 10.1128/aac.02460-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 01/15/2020] [Indexed: 01/29/2023] Open
Abstract
In Enterobacteriales, the AcrAB-TolC efflux pump exports substrates, including antimicrobials, from the cell. Overexpression of AcrAB-TolC can occur after exposure to fluoroquinolones, leading to multidrug resistance. The expression of AcrAB-TolC in Salmonella is primarily regulated by the transcriptional activator RamA. However, other transcriptional activators, such as MarA, SoxRS, and Rob, can influence AcrAB-TolC expression. This study determined whether the overproduction or absence of RamA influences the mutation rate or the phenotype of mutants selected in Salmonella enterica serovar Typhimurium SL1344 after ciprofloxacin exposure. The absence of RamA (SL1344 ramA::aph) resulted in mutation frequencies/rates similar to those of wild-type Salmonella Typhimurium SL1344. However, the overproduction of RamA (SL1344 ramR::aph) and, consequently, AcrB resulted in a significantly higher mutation frequency and rate than for wild-type Salmonella Typhimurium SL1344. Whole-genome sequencing revealed that in addition to selecting gyrA mutants resistant to quinolones, SL1344 and SL1344 ramA::aph also produced multidrug-resistant (MDR) mutants, associated with mutations in soxR Conversely, mutations in SL1344 ramR::aph occurred in gyrA only. Although transcriptional regulators such as SoxRS are believed to play a minor role in AcrAB-TolC regulation under antibiotic selective pressure, we show that soxR mutants can be selected after exposure to ciprofloxacin, including when RamA is absent. This demonstrates that under selective pressure, Salmonella can respond to increased efflux pump expression by mutating other AcrAB-TolC regulatory genes, allowing for the evolution of MDR. Understanding how Salmonella responds to antibiotic pressure in the absence/overproduction of RamA is important if targeting transcriptional regulators to alter efflux is to be considered an avenue for future drug discovery.
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17
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Conjugal transfer of PMQR from uropathogenic E.coli under high ciprofloxacin selection pressure generates gyrA mutation. Microb Pathog 2019; 132:26-29. [DOI: 10.1016/j.micpath.2019.04.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 04/02/2019] [Accepted: 04/11/2019] [Indexed: 11/21/2022]
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18
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Chetri S, Bhowmik D, Dhar D, Chakravarty A, Bhattacharjee A. Effect of concentration gradient carbapenem exposure on expression of bla NDM-1 and acrA in carbapenem resistant Escherichia coli. INFECTION GENETICS AND EVOLUTION 2019; 73:332-336. [PMID: 31170528 DOI: 10.1016/j.meegid.2019.05.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 05/28/2019] [Accepted: 05/31/2019] [Indexed: 10/26/2022]
Abstract
Escherichia coli, one of the major pathogens, frequently exhibits carbapenem resistance. It would be of interest to investigate which of the mechanisms responds when a strain that carries both blaNDM-1 and over expressed AcrAB-TolC efflux pump system is exposed against carbapenem under differential concentration gradient stress. Four different sets of strains were used in the study; (i) Strain that have blaNDM-1 and over expressed AcrAB-TolC system (ii) Strain that harbour blaNDM-1 and express AcrAB-TolC at basal level (iii) the strain that is devoid of blaNDM-1 but having over expressed AcrAB-TolC systems and (iv) E. coli AG100A (ΔAcrAB) and E. coli HUE 1 (ΔAcrAB-TolC) where blaNDM-1was cloned. The Quantitative Real time PCR showed blaNDM-1 was over expressed under meropenem and imipenem stress irrespective of concentration gradient. In case of ertapenem, at lower concentration AcrA were over expressed whereas, at higher concentration blaNDM-1 showed elevated expression. A consistent elevated expression of AcrA and AcrB was observed against all carbapenems in the strains devoid of blaNDM-1 where as in case of the strain with basal level expression of AcrA, no significant over expression could be observed for blaNDM-1. In case of clones in group IV, expression of blaNDM-1 was elevated in the presence of carbapenem stress.
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Affiliation(s)
- Shiela Chetri
- Department of Microbiology, Assam University, Silchar, India
| | | | - Debadatta Dhar
- Department of Microbiology, Silchar Medical College and Hospital, Silchar, India
| | - Atanu Chakravarty
- Department of Microbiology, Silchar Medical College and Hospital, Silchar, India
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19
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Resistance and Virulence Mechanisms of Escherichia coli Selected by Enrofloxacin in Chicken. Antimicrob Agents Chemother 2019; 63:AAC.01824-18. [PMID: 30803968 DOI: 10.1128/aac.01824-18] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 02/04/2019] [Indexed: 11/20/2022] Open
Abstract
This study aimed to investigate the genetic characteristics, antibiotic resistance patterns, and novel mechanisms involved in fluoroquinolone (FQ) resistance in commensal Escherichia coli isolates. The E. coli isolates were recovered from a previous clinical study and subjected to antimicrobial susceptibility testing and molecular typing. Known mechanisms of FQ resistance (target site mutations, plasmid-mediated quinolone resistance [PMQR] genes, relative expression levels of efflux pumps and porins) were detected using DNA sequencing of PCR products and real-time quantitative PCR. Whole-genome shotgun sequencing was performed on 11 representative strains to screen for single nucleotide polymorphisms (SNPs). The function of a key SNP (A1541G) was investigated by site-directed mutagenesis and allelic exchange. The results showed that long-term enrofloxacin treatment selected multidrug-resistant (MDR) E. coli isolates in the chicken gut and that these E. coli isolates had diverse genetic backgrounds. Multiple genetic alterations, including double mutations on GyrA (S83L and D87N), a single mutation on ParC (S80I) and ParE (S458E), activation of efflux pumps, and the presence of the QnrS1 protein, contributed to the high-level FQ resistance (enrofloxacin MIC [MICENR] ≥ 128 μg/ml), while the relatively low-level FQ resistance (MICENR = 8 or 16 μg/ml) was commonly mediated by decreased expression of the porin OmpF, besides enhancement of the efflux pumps. No significant relationship was observed between resistance mechanisms and virulence genes. Introduction of the A1541G mutation on aegA was able to increase FQ susceptibility by 2-fold. This study contributes to a better understanding of the development of MDR and the differences underlying the mechanisms of high-level and low-level FQ resistance in E. coli.
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20
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Anes J, Sivasankaran SK, Muthappa DM, Fanning S, Srikumar S. Exposure to Sub-inhibitory Concentrations of the Chemosensitizer 1-(1-Naphthylmethyl)-Piperazine Creates Membrane Destabilization in Multi-Drug Resistant Klebsiella pneumoniae. Front Microbiol 2019; 10:92. [PMID: 30814979 PMCID: PMC6381021 DOI: 10.3389/fmicb.2019.00092] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/16/2019] [Indexed: 01/23/2023] Open
Abstract
Antimicrobial efflux is one of the important mechanisms causing multi-drug resistance (MDR) in bacteria. Chemosensitizers like 1-(1-naphthylmethyl)-piperazine (NMP) can inhibit an efflux pump and therefore can overcome MDR. However, secondary effects of NMP other than efflux pump inhibition are rarely investigated. Here, using phenotypic assays, phenotypic microarray and transcriptomic assays we show that NMP creates membrane destabilization in MDR Klebsiella pneumoniae MGH 78578 strain. The NMP mediated membrane destabilization activity was measured using β-lactamase activity, membrane potential alteration studies, and transmission electron microscopy assays. Results from both β-lactamase and membrane potential alteration studies shows that both outer and inner membranes are destabilized in NMP exposed K. pneumoniae MGH 78578 cells. Phenotypic Microarray and RNA-seq were further used to elucidate the metabolic and transcriptional signals underpinning membrane destabilization. Membrane destabilization happens as early as 15 min post-NMP treatment. Our RNA-seq data shows that many genes involved in envelope stress response were differentially regulated in the NMP treated cells. Up-regulation of genes encoding the envelope stress response and repair systems show the distortion in membrane homeostasis during survival in an environment containing sub-inhibitory concentration of NMP. In addition, the lsr operon encoding the production of autoinducer-2 responsible for biofilm production was down-regulated resulting in reduced biofilm formation in NMP treated cells, a phenotype confirmed by crystal violet-based assays. We postulate that the early membrane disruption leads to destabilization of inner membrane potential, impairing ATP production and consequently resulting in efflux pump inhibition.
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Affiliation(s)
- João Anes
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
| | | | - Dechamma M Muthappa
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
| | - Séamus Fanning
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland.,Institute for Global Food Security, Queen's University Belfast, Belfast, United Kingdom
| | - Shabarinath Srikumar
- School of Public Health, Physiotherapy and Sports Science, Centre for Food Safety, Science Centre South, University College Dublin, Dublin, Ireland
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21
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Atac N, Kurt-Azap O, Dolapci I, Yesilkaya A, Ergonul O, Gonen M, Can F. The Role of AcrAB-TolC Efflux Pumps on Quinolone Resistance of E. coli ST131. Curr Microbiol 2018; 75:1661-1666. [PMID: 30283991 DOI: 10.1007/s00284-018-1577-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 09/28/2018] [Indexed: 01/06/2023]
Abstract
Escherichia coli ST131 is a cause for global concern because of its high multidrug resistance and several virulence factors. In this study, the contribution of acrAB-TolC efflux system of E. coli ST131 to fluoroquinolone resistance was evaluated. A total of nonrepetitive 111 ciprofloxacin-resistant E. coli isolates were included in the study. Multilocus sequence typing was used for genotyping. Expressions of acrA, acrB, and TolC efflux pump genes were measured by RT-PCR. Mutations in marA, gyrA, parC, and aac(6')-lb-cr positivity were studied by Sanger sequencing. Sixty-four (57.7%) of the isolates were classified as ST131, and 52 (81.3%) of the ST131 isolates belonged to H30-Rx subclone. In ST131, CTX-M 15 positivity (73%) and aac(6')-lb-cr carriage (75%) were significantly higher than those in non-ST131 (12.8% and 51%, respectively) (P < 0.05). The ampicillin-sulbactam (83%) resistance was higher, and gentamicin resistance (20%) was lower in ST131 than that in non-ST131 (64% and 55%, respectively) (P = 0.001 and P = 0.0002). Numbers of the isolates with MDR or XDR profiles did not differ in both groups. Multiple in-dels (up to 16) were recorded in all quinolone-resistant isolates. However, marA gene was more overexpressed in ST131 compared to that in non-ST131 (median 5.98 vs. 3.99; P = 0.0007). Belonging to H30-Rx subclone, isolation site, ciprofloxacin MIC values did not correlate with efflux pump expressions. In conclusion, the marA regulatory gene of AcrAB-TolC efflux pump system has a significant impact on quinolone resistance and progression to MDR profile in ST131 clone. Efflux pump inhibitors might be alternative drugs for the treatment of infections caused by E. coli ST131 if used synergistically in combination with antibiotics.
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Affiliation(s)
- N Atac
- Department of Medical Microbiology, Koc University School of Medicine, Istanbul, Turkey.
| | - O Kurt-Azap
- Department of Infectious Diseases and Clinical Microbiology, Baskent University School of Medicine, Ankara, Turkey
| | - I Dolapci
- Department of Medical Microbiology, Ankara University School of Medicine, Ankara, Turkey
| | - A Yesilkaya
- Department of Infectious Diseases and Clinical Microbiology, Baskent University School of Medicine, Ankara, Turkey
| | - O Ergonul
- Department of Infectious Diseases and Clinical Microbiology, Koc University School of Medicine, Istanbul, Turkey
| | - M Gonen
- Industrial Engineering, Koc University College of Engineering, Istanbul, Turkey
| | - F Can
- Department of Medical Microbiology, Koc University School of Medicine, Istanbul, Turkey
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22
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Srinivasan B, Tonddast-Navaei S, Roy A, Zhou H, Skolnick J. Chemical space of Escherichia coli dihydrofolate reductase inhibitors: New approaches for discovering novel drugs for old bugs. Med Res Rev 2018; 39:684-705. [PMID: 30192413 DOI: 10.1002/med.21538] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 07/16/2018] [Accepted: 08/09/2018] [Indexed: 12/15/2022]
Abstract
Escherichia coli Dihydrofolate reductase is an important enzyme that is essential for the survival of the Gram-negative microorganism. Inhibitors designed against this enzyme have demonstrated application as antibiotics. However, either because of poor bioavailability of the small-molecules resulting from their inability to cross the double membrane in Gram-negative bacteria or because the microorganism develops resistance to the antibiotics by mutating the DHFR target, discovery of new antibiotics against the enzyme is mandatory to overcome drug-resistance. This review summarizes the field of DHFR inhibition with special focus on recent efforts to effectively interface computational and experimental efforts to discover novel classes of inhibitors that target allosteric and active-sites in drug-resistant variants of EcDHFR.
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Affiliation(s)
- Bharath Srinivasan
- Center for the Study of Systems Biology, School of Biology, Georgia Institute of Technology, Atlanta, Georgia
| | - Sam Tonddast-Navaei
- Center for the Study of Systems Biology, School of Biology, Georgia Institute of Technology, Atlanta, Georgia
| | - Ambrish Roy
- Center for the Study of Systems Biology, School of Biology, Georgia Institute of Technology, Atlanta, Georgia
| | - Hongyi Zhou
- Center for the Study of Systems Biology, School of Biology, Georgia Institute of Technology, Atlanta, Georgia
| | - Jeffrey Skolnick
- Center for the Study of Systems Biology, School of Biology, Georgia Institute of Technology, Atlanta, Georgia
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23
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Abdelhamid SM, Abozahra RR. Expression of the Fluoroquinolones Efflux Pump Genes acrA and mdfA in Urinary Escherichia coli Isolates. Pol J Microbiol 2018; 66:25-30. [PMID: 29359692 DOI: 10.5604/17331331.1234990] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Escherichia coli is one of the most frequent causes of urinary tract infections. Efflux system overexpression is reported to contribute to E. coli resistance to several antibiotics. Our aim in this study was to investigate the relation between antibiotic resistance and the expression of the efflux pump genes acrA and mdfA in E. coli by real-time reverse transcription-PCR. We tested the in vitro susceptibilities to 12 antibiotics in 28 clinical isolates of E. coli obtained from urine samples. We also determined the minimum inhibitory concentrations of levofloxacin to these samples. We then revealed significant correlations between the overexpression of both mdfA and acrA and MICs of levofloxacin. In conclusion, we demonstrated that the increased expression of efflux pump genes such as mdfA and acrA can lead to levofloxacin resistance in E. coli. These findings contribute to further understanding of the molecular mechanisms of efflux pump systems and how they contribute to antibiotic resistance.
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Vinué L, Hooper DC, Jacoby GA. Chromosomal mutations that accompany qnr in clinical isolates of Escherichia coli. Int J Antimicrob Agents 2018; 51:479-483. [PMID: 29360506 DOI: 10.1016/j.ijantimicag.2018.01.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 01/10/2018] [Accepted: 01/13/2018] [Indexed: 10/18/2022]
Abstract
We examined 13 qnr-positive and 14 qnr-negative clinical isolates of Escherichia coli for mutations previously seen in a qnr-containing laboratory strain exposed to supra minimum inhibitory concentrations (MICs) of ciprofloxacin. Among the qnr-positive strains, those with ciprofloxacin MICs of ≥ 2 µg/mL had at least one mutation in gyrA. Mutations in parC were present in strains with a ciprofloxacin MIC of ≥ 128 µg/mL. The 6 most ciprofloxacin-resistant strains contained additional plasmid-mediated quinolone resistance determinants. aac(6')-Ib-cr was found in 5 of the 6 strains. Eleven of the 13 strains had alterations in MarR, 9 in SoxR, and 5 had mutations in AcrR. All had elevated expression of at least one efflux pump gene, predominantly acrA (92% of the strains), followed by mdtE (54%) and ydhE (46%). Nine had functionally silent alterations in rfa, two had mutations in gmhB, and one of these also had a mutation in surA. An E. coli with ciprofloxacin MIC of 1024 µg/mL contained 4 different plasmid-mediated quinolone resistance determinants as well as gyrA, parC, parE and pump overexpression mutations. Nine of the 14 qnr-negative strains had mutations in topoisomerase genes with a ciprofloxacin MIC of 0.25 to 256 µg/mL. The three most resistant strains also had mutations in parE. Twelve had alterations in MarR, 10 in SoxR and 5 in AcrR. Ten of the 14 strains had elevated expression of efflux pumps with acrA (71.4%), followed by ydhE (50%) and mdtE (14.3%). A diversity of resistance mechanisms occurs in clinical isolates with and without qnr genes.
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Affiliation(s)
- Laura Vinué
- Massachusetts General Hospital, Boston, Massachusetts, USA.
| | - David C Hooper
- Massachusetts General Hospital, Boston, Massachusetts, USA
| | - George A Jacoby
- Lahey Hospital and Medical Center, Burlington, Massachusetts, USA
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Matsumura Y, Noguchi T, Tanaka M, Kanahashi T, Yamamoto M, Nagao M, Takakura S, Ichiyama S. Population structure of Japanese extraintestinal pathogenic Escherichia coli and its relationship with antimicrobial resistance. J Antimicrob Chemother 2017; 72:1040-1049. [PMID: 28077674 DOI: 10.1093/jac/dkw530] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 11/10/2016] [Indexed: 12/23/2022] Open
Abstract
Objectives To define the population structure of extraintestinal pathogenic Escherichia coli (ExPEC) in Japan and its relationship with antimicrobial resistance and the major resistance mechanisms for fluoroquinolones and β-lactams, we designed a multicentre prospective study. Methods A total of 329 ExPEC isolates were collected at 10 Japanese acute-care hospitals during December 2014. We defined the clonal groups of ExPEC by fumC and fimH sequencing (CH typing). Antimicrobial susceptibility testing of 18 agents and the detection of mutations in quinolone resistance-determining regions (QRDRs) and β-lactamases were performed. Results Among the study isolates, 103 CH types were found, and CH40-30 (25%) and another 10 CH types (35% in total) constituted the major ExPEC population. Ciprofloxacin non-susceptibility, ESBLs and MDR phenotypes were found in 34%, 22% and 33%, respectively. CH40-30, corresponding to the C/H30 clade of the global pandemic ST131 clone, was associated with four QRDR mutations (100%) and bla CTX-M (60%) and was the most frequent type in 15 antimicrobial-non-susceptible populations (dominating 39%-75% of each population, the highest prevalence for ciprofloxacin), the ESBL producers (70%) and the MDR isolates (59%). Isolates that were non-susceptible to nalidixic acid and low-level resistant to ciprofloxacin with one or two QRDR mutations represented 16% of the study isolates and were distributed among the eight major and non-major CH types. Conclusions More than half of the ExPEC population in Japan consisted of 11 major clones. Of these clones, the CH40-30-ST131-C/H30 clone was the predominant antimicrobial-resistant population. The presence of major clones with low-level ciprofloxacin resistance supports the potential future success of a non-ST131 fluoroquinolone-resistant clone.
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Zhang WH, Zhang CZ, Liu ZJ, Gu XX, Li W, Yang L, Liu YH, Zeng ZL, Jiang HX. In VitroDevelopment of Ciprofloxacin Resistance ofSalmonella entericaSerovars Typhimurium, Enteritidis, and Indiana Isolates from Food Animals. Microb Drug Resist 2017; 23:687-694. [DOI: 10.1089/mdr.2016.0119] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Wen-Hui Zhang
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
| | - Chuan-Zhen Zhang
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
| | - Zhi-Jie Liu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
| | - Xi-Xi Gu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
| | - Wan Li
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
| | - Ling Yang
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
| | - Ya-Hong Liu
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
| | - Zhen-Ling Zeng
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
| | - Hong-Xia Jiang
- National Risk Assessment Laboratory for Antimicrobial Resistance of Animal Original Bacteria, College of Veterinary Medicine, South China Agricultural University (SCAU), Guangzhou, China
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High incidence of fluoroquinolone resistance and effect of efflux pump inhibitors on moxifloxacin resistance among Mycobacterium tuberculosis isolates causing urinary tract infection in Taiwan. Int J Antimicrob Agents 2017; 50:491-495. [PMID: 28668684 DOI: 10.1016/j.ijantimicag.2017.04.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/21/2017] [Accepted: 04/12/2017] [Indexed: 11/21/2022]
Abstract
This study explored the prevalence of urinary tract tuberculosis (UTB) and whether efflux pump activation accounts for resistance to moxifloxacin in Taiwan. Of 3034 patients with culture-confirmed TB from 2005-2012, 47 patients (1.5%) with UTB were included in this study. Minimum inhibitory concentrations (MICs) of moxifloxacin were determined in the presence and absence of efflux pump inhibitors (EPIs), including verapamil, reserpine and carbonyl cyanide 3-chlorophenylhydrazone (CCCP). EPI responders were defined as isolates with at least a four-fold reduction in MICs in the presence of EPIs. Among the 47 isolates, 24 (51.1%) were resistant to ofloxacin and 22 (46.8%) were resistant to moxifloxacin by the agar proportion method. Among the 22 moxifloxacin-resistant isolates, 19 (86.4%) had low-level resistance (MIC = 1.0-2.0 mg/L). Patients with prior exposure to fluoroquinolones were more likely than non-exposed patients to have moxifloxacin-resistant isolates [14/22 (63.6%) vs. 8/25 (32.0%); P = 0.030]. All 3 isolates with high-level moxifloxacin resistance (MIC ≥ 4.0 mg/L) had mutations in the gyrA or gyrB genes; however, among the 19 isolates with low-level resistance, only 1 (5.3%) had a mutation in the gyrA gene. Among the 19 isolates with low-level moxifloxacin resistance, 16 isolates (84.2%) were EPIs responders, but none of the high-level resistant isolates were EPIs responders. Approximately one-half (46.8%) of the isolates from patients with UTB were resistant to moxifloxacin, and activation of efflux pumps accounted for most low-level moxifloxacin-resistant isolates.
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Han JH, Garrigan C, Johnston B, Nachamkin I, Clabots C, Bilker WB, Santana E, Tolomeo P, Maslow J, Myers J, Carson L, Lautenbach E, Johnson JR. Epidemiology and characteristics of Escherichia coli sequence type 131 (ST131) from long-term care facility residents colonized intestinally with fluoroquinolone-resistant Escherichia coli. Diagn Microbiol Infect Dis 2017; 87:275-280. [PMID: 27939288 PMCID: PMC5292283 DOI: 10.1016/j.diagmicrobio.2016.11.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/15/2016] [Accepted: 11/24/2016] [Indexed: 01/01/2023]
Abstract
The objective of this study was to evaluate molecular and epidemiologic factors associated with Escherichia coli sequence type 131 (ST131) among long-term care facility (LTCF) residents who acquired gastrointestinal tract colonization with fluoroquinolone-resistant E. coli (FQREC). Colonizing isolates from 37 residents who newly developed FQREC colonization at three LTCFs from 2006 to 2008 were evaluated. Twenty-nine (78%) of 37 total FQREC colonizing isolates were ST131. Most ST131 isolates had a distinctive combination of gyrA and parC replacement mutations. The ST131 and non-ST131 isolates differed significantly for the prevalence of many individual virulence factors but not for the proportion that qualified molecularly as extraintestinal pathogenic E. coli (ExPEC) or aggregate virulence factor scores. E. coli ST131 was highly prevalent among LTCF residents with FQREC colonization. Future studies should determine the risk factors for infection among ST131-colonized residents, and assess the potential for increased transmissibility of ST131 in the long-term care setting.
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Affiliation(s)
- Jennifer H Han
- Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, PA; Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA; Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA.
| | - Charles Garrigan
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA
| | - Brian Johnston
- Minneapolis Veterans Affairs Medical Center, Minneapolis, MN; Department of Medicine, University of Minnesota, Minneapolis, MN
| | - Irving Nachamkin
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA
| | - Connie Clabots
- Minneapolis Veterans Affairs Medical Center, Minneapolis, MN
| | - Warren B Bilker
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA; Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA
| | - Evelyn Santana
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA
| | - Pam Tolomeo
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA
| | - Joel Maslow
- GeneOne Life Science, Inc., Seoul, South Korea
| | - Janice Myers
- Coatesville Veterans Affairs Medical Center, Coatesville, PA
| | - Lesley Carson
- Division of Geriatrics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ebbing Lautenbach
- Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, PA; Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, PA; Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA
| | - James R Johnson
- Minneapolis Veterans Affairs Medical Center, Minneapolis, MN; Department of Medicine, University of Minnesota, Minneapolis, MN
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Zeng H, Liu J, Ling J. Efflux inhibitor suppresses Streptococcus mutans virulence properties. FEMS Microbiol Lett 2017; 364:2975576. [DOI: 10.1093/femsle/fnx033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 02/07/2017] [Indexed: 01/26/2023] Open
Affiliation(s)
- Huihui Zeng
- Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, China
- Applied Oral Sciences, Faculty of Dentistry, University of HongKong, HongKong
| | - Jia Liu
- Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, China
| | - Junqi Ling
- Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-Sen University, Guangzhou, China
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Plasmid-mediated quinolone resistance: Two decades on. Drug Resist Updat 2016; 29:13-29. [PMID: 27912841 DOI: 10.1016/j.drup.2016.09.001] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 08/03/2016] [Accepted: 08/29/2016] [Indexed: 11/21/2022]
Abstract
After two decades of the discovery of plasmid-mediated quinolone resistance (PMQR), three different mechanisms have been associated to this phenomenon: target protection (Qnr proteins, including several families with multiple alleles), active efflux pumps (mainly QepA and OqxAB pumps) and drug modification [AAC(6')-Ib-cr acetyltransferase]. PMQR genes are usually associated with mobile or transposable elements on plasmids, and, in the case of qnr genes, are often incorporated into sul1-type integrons. PMQR has been found in clinical and environmental isolates around the world and appears to be spreading. Although the three PMQR mechanisms alone cause only low-level resistance to quinolones, they can complement other mechanisms of chromosomal resistance to reach clinical resistance level and facilitate the selection of higher-level resistance, raising a threat to the treatment of infections by microorganisms that host these mechanisms.
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Prevalence of quinolone resistance mechanisms in Enterobacteriaceae producing acquired AmpC β-lactamases and/or carbapenemases in Spain. Enferm Infecc Microbiol Clin 2016; 35:487-492. [PMID: 27345951 DOI: 10.1016/j.eimc.2016.05.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 05/19/2016] [Accepted: 05/23/2016] [Indexed: 11/23/2022]
Abstract
BACKGROUND Quinolone resistance in Enterobacteriaceae species has increased over the past few years, and is significantly associated to beta-lactam resistance. The aim of this study was to evaluate the prevalence of chromosomal- and plasmid-mediated quinolone resistance in acquired AmpC β-lactamase and/or carbapenemase-producing Enterobacteriaceae isolates. METHODS The presence of chromosomal- and plasmid-mediated quinolone resistance mechanisms [mutations in the quinolone resistance determining region (QRDR) of gyrA and parC and qnr, aac(6')-Ib-cr and qepA genes] was evaluated in 289 isolates of acquired AmpC β-lactamase- and/or carbapenemase-producing Enterobacteriaceae collected between February and July 2009 in 35 Spanish hospitals. RESULTS Plasmid mediated quinolone resistance (PMQR) genes were detected in 92 isolates (31.8%), qnr genes were detected in 83 isolates (28.7%), and the aac(6')-Ib-cr gene was detected in 20 isolates (7%). qnrB4 gene was the most prevalent qnr gene detected (20%), associated, in most cases, with DHA-1. Only 14.6% of isolates showed no mutations in gyrA or parC with a ciprofloxacin MIC of 0.5mg/L or higher, whereas PMQR genes were detected in 90% of such isolates. CONCLUSION qnrB4 gene was the most prevalent PMQR gene detected, and was significantly associated with acquired AmpC β-lactamase DHA-1. PMQR determinants in association with other chromosomal-mediated quinolone resistance mechanisms, different to mutations in gyrA and parC (increased energy-dependent efflux, altered lipopolysaccharide or porin loss), could lead to ciprofloxacin MIC values that exceed breakpoints established by the main international committees to define clinical antimicrobial susceptibility breakpoints.
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Takrouri K, Cooper HD, Spaulding A, Zucchi P, Koleva B, Cleary DC, Tear W, Beuning PJ, Hirsch EB, Aggen JB. Progress against Escherichia coli with the Oxazolidinone Class of Antibacterials: Test Case for a General Approach To Improving Whole-Cell Gram-Negative Activity. ACS Infect Dis 2016; 2:405-26. [PMID: 27627629 DOI: 10.1021/acsinfecdis.6b00003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Novel antibacterials with activity against the Gram-negative bacteria associated with nosocomial infections, including Escherichia coli and other Enterobacteriaceae, are urgently needed due to the increasing prevalence of multidrug-resistant strains. A major obstacle that has stalled progress on nearly all small-molecule classes with potential for activity against these species has been achieving sufficient whole-cell activity, a difficult challenge due to the formidable outer membrane and efflux barriers intrinsic to these species. Using a set of compound design principles derived from available information relating physicochemical properties to Gram-negative entry or activity, we synthesized and evaluated a focused library of oxazolidinone analogues, a currently narrow spectrum class of antibacterials active only against Gram-positive bacteria. In this series, we have explored the effectiveness for improving Gram-negative activity by identifying and combining beneficial structural modifications in the C-ring region. We have found polar and/or charge-carrying modifications that, when combined in hybrid C-ring analogues, appear to largely overcome the efflux and/or permeability barriers, resulting in improved Gram-negative activity. In particular, those analogues least effected by efflux and the permeation barrier had significant zwitterionic character.
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Affiliation(s)
- Khuloud Takrouri
- 64 Berkshire Street, Apartment 3, Cambridge, Massachusetts 02141, United States
| | | | - Andrew Spaulding
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Paola Zucchi
- Department
of Pharmacy and Health Systems Sciences, School of Pharmacy, Northeastern University, Boston, Massachusetts 02115, United States
| | - Bilyana Koleva
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Dillon C. Cleary
- 99 Spruce Street, Middleboro, Massachusetts 02346, United States
| | - Westley Tear
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Penny J. Beuning
- Department of Chemistry and Chemical Biology, Northeastern University, Boston, Massachusetts 02115, United States
| | - Elizabeth B. Hirsch
- Department
of Pharmacy and Health Systems Sciences, School of Pharmacy, Northeastern University, Boston, Massachusetts 02115, United States
| | - James B. Aggen
- Revolution Medicines, 700 Saginaw Drive, Redwood City, California 94063, United States
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Feng Y, Hodiamont CJ, van Hest RM, Brul S, Schultsz C, ter Kuile BH. Development of Antibiotic Resistance during Simulated Treatment of Pseudomonas aeruginosa in Chemostats. PLoS One 2016; 11:e0149310. [PMID: 26872140 PMCID: PMC4752458 DOI: 10.1371/journal.pone.0149310] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/29/2016] [Indexed: 11/24/2022] Open
Abstract
During treatment of infections with antibiotics in critically ill patients in the intensive care resistance often develops. This study aims to establish whether under those conditions this resistance can develop de novo or that genetic exchange between bacteria is by necessity involved. Chemostat cultures of Pseudomonas aeruginosa were exposed to treatment regimes with ceftazidime and meropenem that simulated conditions expected in patient plasma. Development of antibiotic resistance was monitored and mutations in resistance genes were searched for by sequencing PCR products. Even at the highest concentrations that can be expected in patients, sufficient bacteria survived in clumps of filamentous cells to recover and grow out after 3 to 5 days. At the end of a 7 days simulated treatment, the minimal inhibitory concentration (MIC) had increased by a factor between 10 and 10,000 depending on the antibiotic and the treatment protocol. The fitness costs of resistance were minimal. In the resistant strains, only three mutations were observed in genes associated with beta-lactam resistance. The development of resistance often observed during patient treatment can be explained by de novo acquisition of resistance and genetic exchange of resistance genes is not by necessity involved. As far as conclusions based on an in vitro study using P. aeruginosa and only two antibiotics can be generalized, it seems that development of resistance can be minimized by treating with antibiotics in the highest concentration the patient can endure for the shortest time needed to eliminate the infection.
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Affiliation(s)
- Yanfang Feng
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute of Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Caspar J. Hodiamont
- Department of Medical Microbiology, Academic Medical Center, Amsterdam, the Netherlands
| | - Reinier M. van Hest
- Department of Hospital Pharmacy & Clinical Pharmacology, Academic Medical Center, Amsterdam, the Netherlands
| | - Stanley Brul
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute of Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Constance Schultsz
- Department of Medical Microbiology, Academic Medical Center, Amsterdam, the Netherlands
- Department of Global Health-Amsterdam Institute for Global Health and Development, Academic Medical Center, Amsterdam, The Netherlands
| | - Benno H. ter Kuile
- Department of Molecular Biology and Microbial Food Safety, Swammerdam Institute of Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- Office for Risk Assessment and Research Coordination Netherlands Food and Consumer Product Safety Authority, Utrecht, The Netherlands
- * E-mail: ;
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Suppression of Emergence of Resistance in Pathogenic Bacteria: Keeping Our Powder Dry, Part 2. Antimicrob Agents Chemother 2015; 60:1194-201. [PMID: 26711766 DOI: 10.1128/aac.02231-15] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We are in a crisis of bacterial resistance. For economic reasons, most pharmaceutical companies are abandoning antimicrobial discovery efforts, while, in health care itself, infection control and antibiotic stewardship programs have generally failed to prevent the spread of drug-resistant bacteria. At this point, what can be done? The first step has been taken. Governments and international bodies have declared there is a worldwide crisis in antibiotic drug resistance. As discovery efforts begin anew, what more can be done to protect newly developing agents and improve the use of new drugs to suppress resistance emergence? A neglected path has been the use of recent knowledge regarding antibiotic dosing as single agents and in combination to minimize resistance emergence, while also providing sufficient early bacterial kill. In this review, we look at the data for resistance suppression. Approaches include increasing the intensity of therapy to suppress resistant subpopulations; developing concepts of clinical breakpoints to include issues surrounding suppression of resistance; and paying attention to the duration of therapy, which is another important issue for resistance suppression. New understanding of optimizing combination therapy is of interest for difficult-to-treat pathogens like Pseudomonas aeruginosa, Acinetobacter spp., and multidrug-resistant (MDR) Enterobacteriaceae. These lessons need to be applied to our old drugs as well to preserve them and to be put into national and international antibiotic resistance strategies. As importantly, from a regulatory perspective, new chemical entities should have a resistance suppression plan at the time of regulatory review. In this way, we can make the best of our current situation and improve future prospects.
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Santos Costa S, Viveiros M, Rosato AE, Melo-Cristino J, Couto I. Impact of efflux in the development of multidrug resistance phenotypes in Staphylococcus aureus. BMC Microbiol 2015; 15:232. [PMID: 26498754 PMCID: PMC4619429 DOI: 10.1186/s12866-015-0572-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/15/2015] [Indexed: 11/10/2022] Open
Abstract
Background Efflux has been recognized as a resistance mechanism to antimicrobials in Staphylococcus aureus; however its role on the development of clinically relevant resistance is still poorly characterized. This study aimed to examine the impact of efflux on development of resistance to fluoroquinolones and other antimicrobials in S. aureus strains representing relevant phenotypes in terms of antibiotic susceptibility and efflux activity. Methods Two closely related methicillin- and ciprofloxacin-resistant Staphylococcus aureus clinical strains, with different efflux capacity and the pan-susceptible strain ATCC25923 were exposed to constant concentrations of the efflux pump (EP) substrates ciprofloxacin, ethidium bromide and cetrimide. Parental and exposed strains were tested regarding their susceptibility towards antibiotics, biocides and ethidium bromide, efflux capacity and levels of EP gene expression. Occurrence of resistance-associated mutations was screened by sequencing. Results Multidrug resistance phenotypes emerged upon exposure, independently of the substrate or its concentration, which were correlated with increased efflux capacity of the exposed strains. The temporal pattern of EP gene expression disclosed an early-response with high expression of several genes, followed by a late-response, characterized by overexpression of specific genes. The overall cell response was more pronounced for strains with an initial basal efflux activity. Remarkably, detection of the IS256 element in the promoter regions of mgrA and norA, in some cases associated with increased gene expression, suggests that these genes may be hot spots for IS256 insertion events. The results obtained with exposure of ATCC25923 to ciprofloxacin were particularly striking, revealing a step-wise development of fluoroquinolone resistance, with a first efflux-mediated response, followed by the occurrence of a mutation in grlA that resulted in phenotypic resistance. Additionally, challenge by non-fluoroquinolone agents, particularly cetrimide, promoted cross resistance to fluoroquinolones, revealing the potential role of biocides as selective pressure for the emergence of resistance to these antibiotics. Conclusions This study reveals efflux as a significant component of S. aureus resistance to fluoroquinolones and biocides and as a primary mechanism to withstand stress imposed by antimicrobials. This efflux-mediated response can result in the emergence of multidrug resistance in healthcare environments and should be taken into account in the management of this major pathogen. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0572-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Sofia Santos Costa
- Global Health and Tropical Medicine, GHTM, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Rua da Junqueira, 100, 1349-008, Lisbon, Portugal.
| | - Miguel Viveiros
- Global Health and Tropical Medicine, GHTM, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Rua da Junqueira, 100, 1349-008, Lisbon, Portugal.
| | - Adriana E Rosato
- Department of Pathology and Genomic Medicine, Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Houston, TX, USA.
| | - José Melo-Cristino
- Centro Hospitalar Lisboa Norte E.P.E., Instituto de Microbiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Avenida Professor Egas Moniz, 1649-028, Lisbon, Portugal.
| | - Isabel Couto
- Global Health and Tropical Medicine, GHTM, Unidade de Microbiologia Médica, Instituto de Higiene e Medicina Tropical, IHMT, Universidade Nova de Lisboa, UNL, Rua da Junqueira, 100, 1349-008, Lisbon, Portugal.
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Sun Z, Xu Y, Sun Y, Liu Y, Zhang X, Huang H, Li C. Ofloxacin resistance in Mycobacterium tuberculosis is associated with efflux pump activity independent of resistance pattern and genotype. Microb Drug Resist 2015; 20:525-32. [PMID: 24940805 DOI: 10.1089/mdr.2013.0171] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Drug-resistance to ofloxacin (OFX) in Mycobacterium tuberculosis is due to missense mutations in gyrA and other factors, such as alterations in the activity of drug efflux pumps. In this study, we identified 8 extensively drug resistant tuberculosis (XDR-TB), 40 multidrug resistant TB (MDR-TB), 38 polydrug resistant TB (PDR-TB), and 16 single OFX-resistant TB from 102 clinical isolates. We tested the effect of three efflux inhibitors, reserpine, verapamil, and carbonyl cyanide m-chlorophenyl hydrazone (CCCP), on changes in the OFX minimum inhibitory concentration (MIC) using Resazurin microtitre assay. These three inhibitors changed the MICs from 2- to 32-fold, with CCCP having the strongest effect. A total of 55%, 74%, and 83% of the tested isolates had changes in MIC of more than two-fold by reserpine, verapamil, and CCCP, respectively. The inhibitors led to similar fold-changes of OFX MICs in the XDR, MDR, PDR, and single OFX-resistant isolates. For each inhibitor, a higher resistance to OFX was associated with the greater efflux pump activity. There were no significant differences in the effect of efflux pump inhibitors upon Beijing and non-Beijing M. tuberculosis genotypes. Taken together, these results indicate that the efflux pump activity was greater in the isolates higher resistant to OFX and had similar effects on isolates with different drug resistant pattern, and had similar effects on Beijing and non-Beijing genotypes.
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Affiliation(s)
- Zhaogang Sun
- Beijing Key Laboratory in Drug Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing Chest Hospital, Capital Medical University , Beijing, People's Republic of China
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Meireles D, Leite-Martins L, Bessa LJ, Cunha S, Fernandes R, de Matos A, Manaia CM, Martins da Costa P. Molecular characterization of quinolone resistance mechanisms and extended-spectrum β-lactamase production in Escherichia coli isolated from dogs. Comp Immunol Microbiol Infect Dis 2015; 41:43-8. [PMID: 25999092 DOI: 10.1016/j.cimid.2015.04.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 04/26/2015] [Accepted: 04/28/2015] [Indexed: 01/30/2023]
Abstract
The increasing prevalence of antimicrobial resistances is now a worldwide problem. Investigating the mechanisms by which pets harboring resistant strains may receive and/or transfer resistance determinants is essential to better understanding how owners and pets can interact safely. Here, we characterized the genetic determinants conferring resistance to β-lactams and quinolones in 38 multidrug-resistant Escherichia coli isolated from fecal samples of dogs, through PCR and sequencing. The most frequent genotype included the β-lactamase groups TEM (n=5), and both TEM+CTX-M-1 (n=5). Within the CTX-M group, we identified the genes CTX-M-32, CTX-M-1, CTX-M-15, CTX-M-55/79, CTX-M-14 and CTX-M-2/44. Thirty isolates resistant to ciprofloxacin presented two mutations in the gyrA gene and one or two mutations in the parC gene. A mutation in gyrA (reported here for the first time), due to a transversion and transition (TCG→GTG) originating a substitution of a serine by a valine in position 83 was also detected. The plasmid-encoded quinolone resistance gene, qnrs1, was detected in three isolates. Dogs can be a reservoir of genetic determinants conferring antimicrobial resistance and thus may play an important role in the spread of antimicrobial resistance to humans and other co-habitant animals.
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Affiliation(s)
- D Meireles
- Produção Aquática, ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal; Ciências Químicas e das Biomoléculas, Escola Superior de Tecnologia de Saúde do Porto, Instituto Politécnico do Porto, Porto, Portugal
| | - L Leite-Martins
- Produção Aquática, ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal; Clínica Veterinária, ICBAS, Universidade do Porto, Porto, Portugal
| | - L J Bessa
- Produção Aquática, ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal; CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Porto, Portugal
| | - S Cunha
- Produção Aquática, ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal; Ciências Químicas e das Biomoléculas, Escola Superior de Tecnologia de Saúde do Porto, Instituto Politécnico do Porto, Porto, Portugal
| | - R Fernandes
- Ciências Químicas e das Biomoléculas, Escola Superior de Tecnologia de Saúde do Porto, Instituto Politécnico do Porto, Porto, Portugal
| | - A de Matos
- Clínica Veterinária, ICBAS, Universidade do Porto, Porto, Portugal; CECA - Centro de Estudos de Ciência Animal, ICETA - Instituto de Ciências e Tecnologias Agrárias e Agro-Alimentares, Universidade do Porto, Porto, Portugal
| | - C M Manaia
- CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Porto, Portugal
| | - P Martins da Costa
- Produção Aquática, ICBAS - Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto, Porto, Portugal; CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Porto, Portugal.
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Opperman TJ, Nguyen ST. Recent advances toward a molecular mechanism of efflux pump inhibition. Front Microbiol 2015; 6:421. [PMID: 25999939 PMCID: PMC4419859 DOI: 10.3389/fmicb.2015.00421] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/21/2015] [Indexed: 12/25/2022] Open
Abstract
Multidrug resistance (MDR) in Gram-negative pathogens, such as the Enterobacteriaceae and Pseudomonas aeruginosa, poses a significant threat to our ability to effectively treat infections caused by these organisms. A major component in the development of the MDR phenotype in Gram-negative bacteria is overexpression of Resistance-Nodulation-Division (RND)-type efflux pumps, which actively pump antibacterial agents and biocides from the periplasm to the outside of the cell. Consequently, bacterial efflux pumps are an important target for developing novel antibacterial treatments. Potent efflux pump inhibitors (EPIs) could be used as adjunctive therapies that would increase the potency of existing antibiotics and decrease the emergence of MDR bacteria. Several potent inhibitors of RND-type efflux pump have been reported in the literature, and at least three of these EPI series were optimized in a pre-clinical development program. However, none of these compounds have been tested in the clinic. One of the major hurdles to the development of EPIs has been the lack of biochemical, computational, and structural methods that could be used to guide rational drug design. Here, we review recent reports that have advanced our understanding of the mechanism of action of several potent EPIs against RND-type pumps.
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Liu H, Liu X, Li Y, Hao C. Effect of six fluoroquinolones on the expression of four efflux pumps in the multidrug resistant Escherichia coli isolates. World J Microbiol Biotechnol 2015; 31:1041-8. [PMID: 25854862 DOI: 10.1007/s11274-015-1854-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Accepted: 04/04/2015] [Indexed: 11/26/2022]
Abstract
In this study, a total of 78 Escherichia coli clinical isolates were isolated from canines diagnosed with urinary tract infections. 23/78 isolates (29.5 %) showed multidrug resistance (MDR) phenotype, including the isolates both susceptible to fluoroquinolones (FQs) (FQ(S)-MDR, n = 12) and resistant to FQs (FQ(R)-MDR, n = 11). For these MDR isolates, mutations within quinolone-resistance determining region of gyrA and parC were determined by PCR amplification and DNA sequencing. The relative quantification of emrE, acrB, macB, and mdfA genes expression in MDR isolates was determined by quantitative real-time PCR before and after exposure to the FQs (10 µg/ml). The results showed that a temporary exposure to FQs could lead to various degrees of up or down-regulation on the expression of four efflux pumps in MDR isolates depending on the resistant phenotype and the activities of the FQs. Generally, the FQ(R)-MDR isolates showed more obvious changes in average expression levels of these transporters versus the FQ(S)-MDR isolates, with a largest increase in emrE, and followed by acrB, while the expression of macB and mdfA did not change as radically. Meanwhile, there is a reverse relationship between the expression changes and the activities of the FQs tested. The expression was higher in the isolates exposed to enrofloxacin, ciprofloxacin, and orbifloxacin, and followed by the marbofloxacin, gatifloxacin, and pradofloxacin, and the average expression levels of some efflux pumps even decreased as the isolates were exposed to gatifloxacin or pradofloxacin.
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Affiliation(s)
- Haixia Liu
- College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, China
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Rodriguez-Martinez JM, Machuca J, Calvo J, Diaz-de-Alba P, Rodríguez-Mirones C, Gimeno C, Martinez-Martinez L, Pascual Á. Challenges to accurate susceptibility testing and interpretation of quinolone resistance in Enterobacteriaceae: results of a Spanish multicentre study. J Antimicrob Chemother 2015; 70:2038-47. [PMID: 25745103 DOI: 10.1093/jac/dkv059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 02/11/2015] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVES The objective of this study was to evaluate the proficiency of Spanish laboratories with respect to accurate susceptibility testing and the detection and interpretation of quinolone resistance phenotypes in Enterobacteriaceae. METHODS Thirteen strains of Enterobacteriaceae were sent to 62 participating centres throughout Spain; strains harboured GyrA/ParC modifications, reduced permeability and/or plasmid-mediated quinolone resistance genes. The centres were requested to evaluate nalidixic acid and five quinolones, provide raw/interpreted clinical categories and to detect/infer resistance mechanisms. Consensus results from reference centres were used to assign minor, major and very major errors (mEs, MEs and VMEs, respectively). RESULTS Susceptibility testing in the participating centres was frequently performed using the MicroScan WalkAway, Vitek 2 and Wider systems (48%, 30% and 8%, respectively). CLSI/EUCAST breakpoints were used in 71%/29% of the determinations. The percentage of VMEs for all quinolones was well below 2%. Only ofloxacin and moxifloxacin showed higher values for raw VMEs (6.6%), which decreased to 0% and 2.9%, respectively, in the interpreted VMEs. These errors were particularly associated with the CC-03 strain [qnrS2 + aac(6')-Ib-cr]. For MEs, percentages were always <10%, except in the case of ofloxacin and nalidixic acid. There was a significantly higher percentage of all types of errors for strains whose MICs were at the border of clinical breakpoints. CONCLUSIONS The use of different breakpoints and methods, the complexity of mutation-driven and transferable resistance mechanisms and the absence of specific tests for detecting low-level resistance lead to high variability and represent a challenge to accuracy in susceptibility testing, particularly in strains with MICs on the border of clinical breakpoints.
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Affiliation(s)
- José-Manuel Rodriguez-Martinez
- Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - Jesús Machuca
- Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain Unidad de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain
| | - Jorge Calvo
- Hospital Universitario Marques de Valdecilla and Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | | | - Cristina Rodríguez-Mirones
- Hospital Universitario Marques de Valdecilla and Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain
| | - Concha Gimeno
- Servicio de Microbiología, Hospital General de Valencia, Valencia, Spain
| | - Luis Martinez-Martinez
- Hospital Universitario Marques de Valdecilla and Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | - Álvaro Pascual
- Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain Unidad de Enfermedades Infecciosas y Microbiología Clínica, Hospital Universitario Virgen Macarena, Sevilla, Spain
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Yamasaki E, Yamada C, Jin X, Nair GB, Kurazono H, Yamamoto S. Expression of marA is remarkably increased from the early stage of development of fluoroquinolone-resistance in uropathogenic Escherichia coli. J Infect Chemother 2014; 21:105-9. [PMID: 25456896 DOI: 10.1016/j.jiac.2014.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2014] [Revised: 10/08/2014] [Accepted: 10/10/2014] [Indexed: 01/01/2023]
Abstract
BACKGROUND Analyses of efflux pumps overexpression and mutations in quinolone resistance determining region (QRDR) in early stage of development of resistance to fluoroquinolones (FQs) are valuable to discuss countermeasures against them. We induced levofloxacin (LVFX)-resistant strains from susceptible uropathogenic Escherichia coli in vitro to analyze the mechanisms of development of FQs-resistance. METHODS 89 strains were exposed to discontinuous elevation of LVFX dose, and mRNA level of efflux pumps and their regulators as well as mutations developed in QRDR of LVFX-resistant strains were analyzed. RESULTS In 5 strains, a stepwise increase in MIC to LVFX (up to >128 μg/ml)was observed. Compared to the parent strains, additional mutations in QRDR were observed in the strains developing high MIC. Remarkable increase of marA expression was observed even in the early stage of LVFX-resistance development, and it lasted until high-level resistance was developed. On the other hand, moderate increase in acrB expression but only low increase in yhiU, yhiV, mdfA, tolC and sdiA were observed. CONCLUSIONS These results suggested that marA expression is a sensitive marker for early detection of development of LVFX-resistance.
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Affiliation(s)
- Eiki Yamasaki
- Division of Food Hygiene, Department of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan.
| | - Chihiro Yamada
- The Department of Urology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - Xinghua Jin
- The Department of Urology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
| | - G Balakrish Nair
- Translational Health Science and Technology Institute, Gurgaon, Haryana, India
| | - Hisao Kurazono
- Division of Food Hygiene, Department of Animal and Food Hygiene, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido, Japan
| | - Shingo Yamamoto
- The Department of Urology, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan
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Machuca J, Briales A, Labrador G, Díaz-de-Alba P, López-Rojas R, Docobo-Pérez F, Martínez-Martínez L, Rodríguez-Baño J, Pachón ME, Pascual A, Rodríguez-Martínez JM. Interplay between plasmid-mediated and chromosomal-mediated fluoroquinolone resistance and bacterial fitness in Escherichia coli. J Antimicrob Chemother 2014; 69:3203-15. [PMID: 25139837 DOI: 10.1093/jac/dku308] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVES The aim of this study was to analyse the interplay among plasmid-mediated qnr genes, alone or in combination with multiple chromosomal-mediated fluoroquinolone (FQ) resistance determinants, susceptibility to FQs and bacterial fitness in an isogenic Escherichia coli collection. METHODS E. coli ATCC 25922 was used to modify or delete chromosomal genes. qnr genes were cloned into the pBK-CMV vector. The MICs of FQs were determined by microdilution. Mutant prevention concentration and frequency of mutants were evaluated. Bacterial fitness was analysed using ΔlacZ system competition assays using in vitro and in vivo models. RESULTS The relationships between the number of resistance mutations and bacterial fitness were complex. With specific combinations of resistance mechanisms the addition of a new resistance mutation was shown to improve bacterial fitness. qnrA1 caused a decrease in fitness (7%-21%) while qnrS1 caused an increase in fitness (9%-21%) when combined with chromosomal mutations. We identified susceptible triple mutants in which the acquisition of a fourth resistance mutation significantly increased fitness and at the same time reached the clinical resistance level (the acquisition of qnrS1 in a S83L + D87N + ΔmarR genetic background). A strong correlation with the production of reactive oxygen species, as well as changes in susceptibility, was observed following treatment with ciprofloxacin. CONCLUSIONS Our data indicate that there may be critical stages (depending on the genotype) in resistance development, including chromosomal- and plasmid-mediated mechanisms, at which some low-fitness mutants below the resistance breakpoint are able to evolve clinical resistance with just one or two mutations, and show increased fitness.
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Affiliation(s)
- Jesús Machuca
- Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena, Seville, Spain
| | - Alejandra Briales
- Department of Microbiology, University of Seville, Seville, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - Gema Labrador
- Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | | | - Rafael López-Rojas
- Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Fernando Docobo-Pérez
- Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena, Seville, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - Luis Martínez-Martínez
- Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain University Hospital Marques de Valdecilla and Valdecilla Biomedical Research Institute (IDIVAL), Santander, Spain Department of Molecular Biology, University of Cantabria, Santander, Spain
| | - Jesús Rodríguez-Baño
- Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena, Seville, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain Medicine Department, University of Seville, Seville, Spain
| | - Maria Eugenia Pachón
- Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Alvaro Pascual
- Infectious Diseases and Clinical Microbiology Unit, University Hospital Virgen Macarena, Seville, Spain Department of Microbiology, University of Seville, Seville, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
| | - José-Manuel Rodríguez-Martínez
- Department of Microbiology, University of Seville, Seville, Spain Spanish Network for Research in Infectious Diseases (REIPI RD12/0015), Instituto de Salud Carlos III, Madrid, Spain
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Abstract
![]()
Quinolones
are one of the most commonly prescribed classes of antibacterials
in the world and are used to treat a variety of bacterial infections
in humans. Because of the wide use (and overuse) of these drugs, the
number of quinolone-resistant bacterial strains has been growing steadily
since the 1990s. As is the case with other antibacterial agents, the
rise in quinolone resistance threatens the clinical utility of this
important drug class. Quinolones act by converting their targets,
gyrase and topoisomerase IV, into toxic enzymes that fragment the
bacterial chromosome. This review describes the development of the
quinolones as antibacterials, the structure and function of gyrase
and topoisomerase IV, and the mechanistic basis for quinolone action
against their enzyme targets. It will then discuss the following three
mechanisms that decrease the sensitivity of bacterial cells to quinolones.
Target-mediated resistance is the most common and clinically significant
form of resistance. It is caused by specific mutations in gyrase and
topoisomerase IV that weaken interactions between quinolones and these
enzymes. Plasmid-mediated resistance results from extrachromosomal
elements that encode proteins that disrupt quinolone–enzyme
interactions, alter drug metabolism, or increase quinolone efflux.
Chromosome-mediated resistance results from the underexpression of
porins or the overexpression of cellular efflux pumps, both of which
decrease cellular concentrations of quinolones. Finally, this review
will discuss recent advancements in our understanding of how quinolones
interact with gyrase and topoisomerase IV and how mutations in these
enzymes cause resistance. These last findings suggest approaches to
designing new drugs that display improved activity against resistant
strains.
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Affiliation(s)
- Katie J Aldred
- Department of Biochemistry and ‡Department of Medicine (Hematology/Oncology), Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States
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Characterization of a novel pyranopyridine inhibitor of the AcrAB efflux pump of Escherichia coli. Antimicrob Agents Chemother 2013; 58:722-33. [PMID: 24247144 DOI: 10.1128/aac.01866-13] [Citation(s) in RCA: 135] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Members of the resistance-nodulation-division (RND) family of efflux pumps, such as AcrAB-TolC of Escherichia coli, play major roles in multidrug resistance (MDR) in Gram-negative bacteria. A strategy for combating MDR is to develop efflux pump inhibitors (EPIs) for use in combination with an antibacterial agent. Here, we describe MBX2319, a novel pyranopyridine EPI with potent activity against RND efflux pumps of the Enterobacteriaceae. MBX2319 decreased the MICs of ciprofloxacin (CIP), levofloxacin, and piperacillin versus E. coli AB1157 by 2-, 4-, and 8-fold, respectively, but did not exhibit antibacterial activity alone and was not active against AcrAB-TolC-deficient strains. MBX2319 (3.13 μM) in combination with 0.016 μg/ml CIP (minimally bactericidal) decreased the viability (CFU/ml) of E. coli AB1157 by 10,000-fold after 4 h of exposure, in comparison with 0.016 μg/ml CIP alone. In contrast, phenyl-arginine-β-naphthylamide (PAβN), a known EPI, did not increase the bactericidal activity of 0.016 μg/ml CIP at concentrations as high as 100 μM. MBX2319 increased intracellular accumulation of the fluorescent dye Hoechst 33342 in wild-type but not AcrAB-TolC-deficient strains and did not perturb the transmembrane proton gradient. MBX2319 was broadly active against Enterobacteriaceae species and Pseudomonas aeruginosa. MBX2319 is a potent EPI with possible utility as an adjunctive therapeutic agent for the treatment of infections caused by Gram-negative pathogens.
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Valade E, Davin-Regli A, Bolla JM, Pagès JM. Bacterial Membrane, a Key for Controlling Drug Influx and Efflux. Antibiotics (Basel) 2013. [DOI: 10.1002/9783527659685.ch9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Han JH, Bilker WB, Nachamkin I, Tolomeo P, Mao X, Fishman NO, Lautenbach E. Impact of antibiotic use during hospitalization on the development of gastrointestinal colonization with Escherichia coli with reduced fluoroquinolone susceptibility. Infect Control Hosp Epidemiol 2013; 34:1070-6. [PMID: 24018924 PMCID: PMC3979459 DOI: 10.1086/673155] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE Infections due to fluoroquinolone-resistant Escherichia coli (FQREC) are associated with significant morbidity and mortality. Fluoroquinolone resistance likely arises at the level of gastrointestinal colonization. The objective of this study was to identify risk factors for the development of FQREC gastrointestinal tract colonization in hospitalized patients, including the impact of antibiotics prescribed during hospitalization. DESIGN A prospective cohort study was conducted from 2002 to 2004 within a university health system. METHODS Hospitalized patients initially colonized with fluoroquinolone-susceptible E. coli were followed up with serial fecal sampling for new FQREC colonization or until hospital discharge or death. A Cox proportional hazards regression model was developed to identify risk factors for new FQREC colonization, with antibiotic exposure modeled as time-varying covariates. RESULTS Of 395 subjects, 73 (18.5%) became newly colonized with FQREC. Length of stay before sampling (hazard ratio [HR], 1.02 [95% confidence interval (CI), 1.1-1.03]; P = .003) and malignancy (HR, 0.37 [95% CI, 0.21-0.67]; P = .001) were significantly associated with the development of FQREC colonization. In addition, receipt of a first-generation cephalosporin (HR, 1.19 [95% CI, 1.10-1.29]; P < .001) or cefepime (HR, 1.05 [95% CI, 1.00-1.10]; P = .048) during hospitalization increased the risk of new FQREC colonization. CONCLUSIONS The acquisition of FQREC in the hospital setting is complex, and antimicrobial stewardship programs should take into account patterns of antibiotic use in implementing strategies to reduce the development of new FQREC colonization. Future studies are needed to identify risk factors for infection in hospitalized patients newly colonized with FQREC.
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Affiliation(s)
- Jennifer H. Han
- Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Warren B. Bilker
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Irving Nachamkin
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Pam Tolomeo
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Xiangqun Mao
- Department of Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Neil O. Fishman
- Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ebbing Lautenbach
- Division of Infectious Diseases, Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Center for Clinical Epidemiology and Biostatistics, University of Pennsylvania, Philadelphia, Pennsylvania
- Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, Pennsylvania
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Seecoomar GD, Marmol BC, Kwon DH. Promoter deletions of Klebsiella pneumoniae carbapenemase (KPC)-encoding genes (blaKPC -2) and efflux pump (AcrAB) on β-lactam susceptibility in KPC-producing Enterobacteriaceae. FEMS Microbiol Lett 2013; 348:120-6. [PMID: 24033858 DOI: 10.1111/1574-6968.12273] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 09/02/2013] [Accepted: 09/03/2013] [Indexed: 11/27/2022] Open
Abstract
Klebsiella pneumoniae carbapenemase (KPC)-encoding genes containing promoter-deletions (bla(KPC-2a), bla(KPC-2b), and bla(KPC-2c) have disseminated in Enterobacteriaceae. The minimal inhibitory concentrations (MICs) to β-lactams in clinical KPC-producing Enterobacteriaceae range from susceptible to high-level resistant, resulting in diagnostic problems. To better understand the variability in β-lactam MICs among KPC-producing Enterobacteriaceae, three isoforms of bla(KPC-2) gene were used to transform Escherichia coli W4573 and its deletion mutant of an efflux pump (AcrAB) to examine the effects on β-lactam susceptibility. MICs to β-lactams in E. coli W4573 and its acrAB mutant strain increased 1- to 500-fold (MIC from 0.125 to 64 μg mL(-1) of aztreonam) in the bla(KPC-2a), bla(KPC-2b), and bla(KPC-2c) transformants compared with the cloning vector alone. However, transformants of the acrAB mutant strain remained susceptible to all β-lactams tested except for aztreonam and carbenicillin. Levels of the three promoters' length and carbapenemase activities in the transformants harboring the bla(KPC-2a), bla(KPC-2b), and bla(KPC-2c) were correlated to the levels of β-lactam MICs in both E. coli W4573 and its mutant of an efflux pump (AcrAB). Overall, these results suggest that promoter-deletions of bla(KPC-2) gene and AcrAB may be associated with the variability in β-lactam MICs in KPC-producing Enterobacteriaceae.
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Ruiz C, Levy SB. Regulation of acrAB expression by cellular metabolites in Escherichia coli. J Antimicrob Chemother 2013; 69:390-9. [PMID: 24043404 DOI: 10.1093/jac/dkt352] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES Multidrug efflux pumps mediate resistance to antibiotics and other toxic compounds. We studied the role of AcrAB-TolC, the main efflux pump in Escherichia coli, in regulating gene expression. METHODS Deletion mutants, an acrABp-lacZ fusion and reverse transcription-real-time quantitative PCR experiments were used to study the role of AcrAB-TolC and metabolism in regulating gene expression of the acrAB operon and its transcriptional regulators. RESULTS Deletion of the acrB gene increased the expression of the acrAB operon. A similar induction of acrAB was found when acrA or tolC was deleted, and when the pump function was inhibited using phenylalanine-arginine-β-naphthylamide. The induction of acrAB in the ΔacrB strain was totally (AcrR or SoxS) or partially (SoxR or MarA) prevented when the genes for these acrAB regulators were also deleted. The expression of soxS and marA, but not of acrR, was increased in the ΔacrB strain, which also showed altered expression of many other genes related to different cellular processes, including motility. Deletion of the metabolic genes entA and entE (enterobactin biosysnthesis), glpX (gluconeogenesis), cysH (cysteine biosynthesis) and purA (purine biosynthesis) also prevented activation of the acrAB promoter in the ΔacrB strain. Addition of the enterobactin biosynthesis intermediate metabolite 2,3-dihydroxybenzoate induced the expression of acrAB. CONCLUSIONS These results together suggest a model in which the AcrAB-TolC pump effluxes cellular metabolites that are toxic and/or have a signalling role. If the pump is inactivated or inhibited, these metabolites would accumulate, inactivating AcrR and/or up-regulating soxS and marA expression, ultimately triggering the up-regulation of acrAB expression to restore homeostasis.
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Affiliation(s)
- Cristian Ruiz
- Center for Adaptation Genetics and Drug Resistance and the Department of Molecular Biology and Microbiology, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA, USA
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Testing the mutant selection window hypothesis with Escherichia coli exposed to levofloxacin in a rabbit tissue cage infection model. Eur J Clin Microbiol Infect Dis 2013; 33:385-9. [DOI: 10.1007/s10096-013-1968-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
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Han JH, Maslow J, Han X, Xie SX, Tolomeo P, Santana E, Carson L, Lautenbach E. Risk factors for the development of gastrointestinal colonization with fluoroquinolone-resistant Escherichia coli in residents of long-term care facilities. J Infect Dis 2013; 209:420-5. [PMID: 23986544 DOI: 10.1093/infdis/jit471] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND The objective of this study was to assess risk factors for the development of fluoroquinolone (FQ)-resistant Escherichia coli gastrointestinal tract colonization in long-term care facility (LTCF) residents. METHODS A prospective cohort study was conducted from 2006 to 2008 at 3 LTCFs. Residents initially colonized with FQ-susceptible E. coli were followed by means of serial fecal sampling for new FQ-resistant E. coli colonization for up to 12 months or until discharge or death. A Cox proportional hazards regression model was developed to identify risk factors for new FQ-resistant E. coli colonization, with antibiotic and device exposures modeled as time-varying covariates. RESULTS Fifty-seven (47.5%) of 120 residents became newly colonized with FQ-resistant E. coli, with a median time to colonization of 57 days. Fecal incontinence (hazard ratio [HR], 1.78; 95% confidence interval [CI], 1.04-3.06; P = .04) was significantly associated with FQ-resistant E. coli acquisition. Receipt of amoxicillin-clavulanate (HR, 6.48; 95% CI, 1.43-29.4; P = .02) and the presence of a urinary catheter (HR, 3.81; 95% CI, 1.06-13.8; P = .04) during LTCF stay increased the risk of new FQ-resistant E. coli colonization. CONCLUSIONS Acquisition of FQ-resistant E. coli was common, with nearly half of LTCF residents developing new FQ-resistant E. coli colonization. Further studies are needed on interventions to limit the emergence of FQ-resistant E. coli in LTCFs.
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