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Saleh NM, Sudan ESF, Mohamed SH, El-Shahed MM, Hamouda RE, El-Gendy AO, Farag AA. Pathogen Partnerships or Power Struggles? Pseudomonas aeruginosa, and Staphylococcus aureus Dynamics in Cystic Fibrosis. Curr Microbiol 2025; 82:236. [PMID: 40198369 DOI: 10.1007/s00284-025-04167-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Accepted: 02/26/2025] [Indexed: 04/10/2025]
Abstract
Cystic fibrosis (CF) is a polymicrobial infection characterized by interactions among various bacterial species that affect one another's cohabitation. The investigation of interspecies interactions in dual infections is essential to understand their reaction in the environment better and assist in the development of treatment regimens and innovative disease control approaches. Our hypothesis posits that co-infection interactions promote the adaptation of Staphylococcus aureus and Pseudomonas aeruginosa, potentially leading to synergistic action. To explore this, we examined dual-species interactions in co-isolated pairs of these organisms from Egyptian CF patients using laboratory media and artificial sputum media (ASM). Based on demographic data, 82 collected bacterial isolates from single, dual, and triple cultures were identified from 50 enrolled patients. In the interaction of the pairs in mimic media, P. aeruginosa exo-products significantly enhanced the biofilm formation and growth of S. aureus. Conversely, S. aureus did not inhibit P. aeruginosa biofilm formation. Furthermore, the biofilm mode of dual-organism growth provides protection in the CF context, as bacterial biofilms can withstand much higher antimicrobial levels compared to planktonically grown bacteria. Additionally, key biofilm genes regulated by quorum sensing were differentially expressed in both species in an isolate-dependent manner, highlighting their significant role in coexistence dual-species biofilm coexistence. In conclusion, our study illuminates the competitive and cooperative interactions between these two pathogens, which impact their coexistence and encourage biofilm production. This, in turn, accelerates disease progression and compromises patient health.
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Affiliation(s)
- Neveen M Saleh
- Department of Microbiology, Egyptian Drug Authority (Former National Organization for Drug Control and Research (NODCAR)), Giza, Egypt.
- College of Public Health, University of Nebraska Medical Center (UNMC), Omaha, United States.
| | - Esraa S F Sudan
- Department of Microbiology, Egyptian Drug Authority (Former National Organization for Drug Control and Research (NODCAR)), Giza, Egypt
| | - Sara H Mohamed
- Department of Microbiology, Egyptian Drug Authority (Former National Organization for Drug Control and Research (NODCAR)), Giza, Egypt
| | - Maram M El-Shahed
- Department of Microbiology, Egyptian Drug Authority (Former National Organization for Drug Control and Research (NODCAR)), Giza, Egypt
| | - Reda E Hamouda
- Department of Animal Production Systems Research, Animal Production Research Institute, Agricultural Research Center, Ministry of Agriculture and Land Reclamation, Giza, Egypt
| | - Ahmed Osama El-Gendy
- Microbiology and Immunology Department, Faculty of Pharmacy, Beni-Suef University, Beni Suef, 62514, Egypt
| | - Ahmed A Farag
- Microbiology and Immunology Department, Faculty of Pharmacy, Beni-Suef University, Beni Suef, 62514, Egypt
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Monroy-Pérez E, Herrera-Gabriel JP, Olvera-Navarro E, Ugalde-Tecillo L, García-Cortés LR, Moreno-Noguez M, Martínez-Gregorio H, Vaca-Paniagua F, Paniagua-Contreras GL. Molecular Properties of Virulence and Antibiotic Resistance of Pseudomonas aeruginosa Causing Clinically Critical Infections. Pathogens 2024; 13:868. [PMID: 39452738 PMCID: PMC11510431 DOI: 10.3390/pathogens13100868] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2024] [Revised: 09/29/2024] [Accepted: 10/02/2024] [Indexed: 10/26/2024] Open
Abstract
The increase in the number of hospital strains of hypervirulent and multidrug resistant (MDR) Pseudomonas aeruginosa is a major health problem that reduces medical treatment options and increases mortality. The molecular profiles of virulence and multidrug resistance of P. aeruginosa-associated hospital and community infections in Mexico have been poorly studied. In this study, we analyzed the different molecular profiles associated with the virulence genotypes related to multidrug resistance and the genotypes of multidrug efflux pumps (mex) in P. aeruginosa causing clinically critical infections isolated from Mexican patients with community- and hospital-acquired infections. Susceptibility to 12 antibiotics was determined using the Kirby-Bauer method. The identification of P. aeruginosa and the detection of virulence and efflux pump system genes were performed using conventional PCR. All strains isolated from patients with hospital-acquired (n = 67) and community-acquired infections (n = 57) were multidrug resistant, mainly to beta-lactams (ampicillin [96.7%], carbenicillin [98.3%], cefalotin [97.5%], and cefotaxime [87%]), quinolones (norfloxacin [78.2%]), phenicols (chloramphenicol [91.9%]), nitrofurans (nitrofurantoin [70.9%]), aminoglycosides (gentamicin [75%]), and sulfonamide/trimethoprim (96.7%). Most strains (95.5%) isolated from patients with hospital- and community-acquired infections carried the adhesion (pilA) and biofilm formation (ndvB) genes. Outer membrane proteins (oprI and oprL) were present in 100% of cases, elastases (lasA and lasB) in 100% and 98.3%, respectively, alkaline protease (apr) and alginate (algD) in 99.1% and 97.5%, respectively, and chaperone (groEL) and epoxide hydrolase (cif) in 100% and 97.5%, respectively. Overall, 99.1% of the strains isolated from patients with hospital- and community-acquired infections carried the efflux pump system genes mexB and mexY, while 98.3% of the strains carried mexF and mexZ. These findings show a wide distribution of the virulome related to the genotypic and phenotypic profiles of antibiotic resistance and the origin of the strains isolated from patients with hospital- and community-acquired infections, demonstrating that these molecular mechanisms may play an important role in high-pathogenicity infections caused by P. aeruginosa.
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Affiliation(s)
- Eric Monroy-Pérez
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (J.P.H.-G.); (E.O.-N.); (L.U.-T.)
| | - Jennefer Paloma Herrera-Gabriel
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (J.P.H.-G.); (E.O.-N.); (L.U.-T.)
| | - Elizabeth Olvera-Navarro
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (J.P.H.-G.); (E.O.-N.); (L.U.-T.)
| | - Lorena Ugalde-Tecillo
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (J.P.H.-G.); (E.O.-N.); (L.U.-T.)
| | - Luis Rey García-Cortés
- Coordinación de Investigación del Estado de México Oriente, Insitituto Mexicano del Seguro Social, Tlalnepantla de Baz 50090, Mexico;
| | - Moisés Moreno-Noguez
- Coordinación Clínica de Educación e Investigación en Salud, Unidad de Medicina Familiar No. 55, Insitituto Mexicano del Seguro Social Estado de México Oriente, Zumpango 55600, Mexico;
| | - Héctor Martínez-Gregorio
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (H.M.-G.); (F.V.-P.)
- Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico
| | - Felipe Vaca-Paniagua
- Unidad de Biomedicina, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (H.M.-G.); (F.V.-P.)
- Laboratorio Nacional en Salud, Diagnóstico Molecular y Efecto Ambiental en Enfermedades Crónico-Degenerativas, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico
| | - Gloria Luz Paniagua-Contreras
- Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Tlalnepantla 54090, Mexico; (J.P.H.-G.); (E.O.-N.); (L.U.-T.)
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Kabir RB, Ahsan T, Rahman MF, Jobayer M, Shamsuzzaman SM. Biofilm-producing and specific antibiotic resistance genes in Pseudomonas aeruginosa isolated from patients admitted to a tertiary care hospital, Bangladesh. IJID REGIONS 2024; 11:100369. [PMID: 38799795 PMCID: PMC11126856 DOI: 10.1016/j.ijregi.2024.100369] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Revised: 04/21/2024] [Accepted: 04/22/2024] [Indexed: 05/29/2024]
Abstract
Objectives Biofilms are responsible for persistent infections and antimicrobial resistance. Pseudomonas aeruginosa was investigated with its ability to form biofilm by detecting genes responsible for producing biofilms and biofilm-specific antimicrobial resistance. The association between antibiotic resistance and biofilm was investigated. Methods This cross-sectional study was conducted from July 2017 to December 2018. A total of 446 samples (infected burn, surgical wounds, and endotracheal aspirate) were collected from admitted patients of Dhaka Medical College and Hospital, Bangladesh. P. aeruginosa was isolated and identified by biochemical tests and polymerase chain reaction. Biofilm production by tissue culture plate method followed by detection of biofilm-producing genes (pqsA, pslA, pslD, pslH, pelA, lasR) and biofilm-specific antibiotic resistance genes (ndvB, PA1874, PA1876, PA1877) by polymerase chain reaction were done. Antibiotic susceptibility test was carried out by disk diffusion method; for colistin agar dilution method of minimal inhibitory concentration was followed. Results Among 232 (52.02%) positive strains of P. aeruginosa, 24 (10.30%) produced biofilms in tissue culture plate. Among biofilm-producing genes, pqsA was the highest (79.17%). pslA and pelA were 70.83%, pslD 45.83%, pslH and lasR 37.5%. Among biofilm-specific antibiotic resistance genes, 16.67% were ndvB, and 8.33% were PA1874 and PA1877. Biofilm-forming strains were significantly resistant to colistin. Conclusions Detection of biofilm-forming genes may be a good tool for the evaluation of biofilm production, which will help in prompt and better management of chronic or device-associated infections.
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Affiliation(s)
| | - Tasnim Ahsan
- Department of Microbiology, Ibn Sina Medical College, Dhaka, Bangladesh
| | - Md. Faizur Rahman
- Department of Microbiology, Dhaka Medical College, Dhaka, Bangladesh
| | - Mohammad Jobayer
- Department of Microbiology, Dhaka Medical College, Dhaka, Bangladesh
| | - SM Shamsuzzaman
- Department of Microbiology, Dhaka Medical College, Dhaka, Bangladesh
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Okurowska K, Monk PN, Karunakaran E. Increased tolerance to commonly used antibiotics in a Pseudomonas aeruginosa ex vivo porcine keratitis model. MICROBIOLOGY (READING, ENGLAND) 2024; 170:001459. [PMID: 38739119 PMCID: PMC11165664 DOI: 10.1099/mic.0.001459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 04/26/2024] [Indexed: 05/14/2024]
Abstract
Introduction. Bacterial keratitis, particularly caused by Pseudomonas aeruginosa, is challenging to treat because of multi-drug tolerance, often associated with the formation of biofilms. Antibiotics in development are typically evaluated against planktonic bacteria in a culture medium, which may not accurately represent the complexity of infections in vivo.Hypothesis/Gap Statement. Developing a reliable, economic ex vivo keratitis model that replicates some complexity of tissue infections could facilitate a deeper understanding of antibiotic efficacy, thus aiding in the optimization of treatment strategies for bacterial keratitis.Methodology. Here we investigated the efficacy of three commonly used antibiotics (gentamicin, ciprofloxacin and meropenem) against Pseudomonas aeruginosa cytotoxic strain PA14 and invasive strain PA01 using an ex vivo porcine keratitis model.Results. Both strains of P. aeruginosa were susceptible to the MIC of the three tested antibiotics. However, significantly higher concentrations were necessary to inhibit bacterial growth in the minimum biofilm eradication concentration (MBEC) assay, with both strains tolerating concentrations greater than 512 mg l-1 of meropenem. When MIC and higher concentrations than MBEC (1024 mg l-1) of antibiotics were applied, ciprofloxacin exhibited the highest potency against both P. aeruginosa strains, followed by meropenem, while gentamicin showed the least potency. Despite this, none of the antibiotic concentrations used effectively cleared the infection, even after 18 h of continuous exposure.Conclusions. Further exploration of antibiotic concentrations and aligning dosing with clinical studies to validate the model is needed. Nonetheless, our ex vivo porcine keratitis model could be a valuable tool for assessing antibiotic efficacy.
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Affiliation(s)
- Katarzyna Okurowska
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S10 2TN, UK
- National Institute for Health and Care Research, University of Leeds, Leeds LS2 9JT, UK
| | - Peter N. Monk
- Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield S10 2TN, UK
| | - Esther Karunakaran
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield S10 2TN, UK
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Sanz-García F, Laborda P, Ochoa-Sánchez LE, Martínez JL, Hernando-Amado S. The Pseudomonas aeruginosa Resistome: Permanent and Transient Antibiotic Resistance, an Overview. Methods Mol Biol 2024; 2721:85-102. [PMID: 37819517 DOI: 10.1007/978-1-0716-3473-8_7] [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: 10/13/2023]
Abstract
One of the most concerning characteristics of Pseudomonas aeruginosa is its low susceptibility to several antibiotics of common use in clinics, as well as its facility to acquire increased resistance levels. Consequently, the study of the antibiotic resistance mechanisms of this bacterium is of relevance for human health. For such a study, different types of resistance should be distinguished. The intrinsic resistome is composed of a set of genes, present in the core genome of P. aeruginosa, which contributes to its characteristic, species-specific, phenotype of susceptibility to antibiotics. Acquired resistance refers to those genetic events, such as the acquisition of mutations or antibiotic resistance genes that reduce antibiotic susceptibility. Finally, antibiotic resistance can be transiently acquired in the presence of specific compounds or under some growing conditions. The current article provides information on methods currently used to analyze intrinsic, mutation-driven, and transient antibiotic resistance in P. aeruginosa.
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Affiliation(s)
| | - Pablo Laborda
- Centro Nacional de Biotecnología, CSIC, Madrid, Spain
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Bano S, Hassan N, Rafiq M, Hassan F, Rehman M, Iqbal N, Ali H, Hasan F, Kang YQ. Biofilms as Battlefield Armor for Bacteria against Antibiotics: Challenges and Combating Strategies. Microorganisms 2023; 11:2595. [PMID: 37894253 PMCID: PMC10609369 DOI: 10.3390/microorganisms11102595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/25/2023] [Accepted: 09/04/2023] [Indexed: 10/29/2023] Open
Abstract
Bacterial biofilms are formed by communities, which are encased in a matrix of extracellular polymeric substances (EPS). Notably, bacteria in biofilms display a set of 'emergent properties' that vary considerably from free-living bacterial cells. Biofilms help bacteria to survive under multiple stressful conditions such as providing immunity against antibiotics. Apart from the provision of multi-layered defense for enabling poor antibiotic absorption and adaptive persistor cells, biofilms utilize their extracellular components, e.g., extracellular DNA (eDNA), chemical-like catalase, various genes and their regulators to combat antibiotics. The response of biofilms depends on the type of antibiotic that comes into contact with biofilms. For example, excessive production of eDNA exerts resistance against cell wall and DNA targeting antibiotics and the release of antagonist chemicals neutralizes cell membrane inhibitors, whereas the induction of protein and folic acid antibiotics inside cells is lowered by mutating genes and their regulators. Here, we review the current state of knowledge of biofilm-based resistance to various antibiotic classes in bacteria and genes responsible for biofilm development, and the key role of quorum sensing in developing biofilms and antibiotic resistance is also discussed. In this review, we also highlight new and modified techniques such as CRISPR/Cas, nanotechnology and bacteriophage therapy. These technologies might be useful to eliminate pathogens residing in biofilms by combating biofilm-induced antibiotic resistance and making this world free of antibiotic resistance.
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Affiliation(s)
- Sara Bano
- Applied Environmental and Geomicrobiology Laboratory, Department of Microbiology, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Noor Hassan
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering-College, Pakistan Institute of Engineering and Applied Sciences, Islamabad 44000, Pakistan
| | - Muhammad Rafiq
- Department of Microbiology, Balochistan University of Information Technology, Engineering and Management Sciences, Quetta 87300, Pakistan
| | - Farwa Hassan
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering-College, Pakistan Institute of Engineering and Applied Sciences, Islamabad 44000, Pakistan
| | - Maliha Rehman
- Department of Microbiology, Balochistan University of Information Technology, Engineering and Management Sciences, Quetta 87300, Pakistan
| | - Naveed Iqbal
- Department of Biotechnology & Informatics, Balochistan University of Information Technology, Engineering and Management Sciences, Quetta 87300, Pakistan
- The Department of Paediatrics and Child Health, Aga Khan University, Karachi 74800, Pakistan
| | - Hazrat Ali
- Industrial Biotechnology Division, National Institute for Biotechnology and Genetic Engineering-College, Pakistan Institute of Engineering and Applied Sciences, Islamabad 44000, Pakistan
| | - Fariha Hasan
- Applied Environmental and Geomicrobiology Laboratory, Department of Microbiology, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Ying-Qian Kang
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education of Guizhou, Guiyang 550025, China
- Key Laboratory of Medical Microbiology and Parasitology, School of Basic Medical Sciences, Guizhou Medical University, Guiyang 550025, China
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Mahrous SH, El-Balkemy FA, Abo-Zeid NZ, El-Mekkawy MF, El Damaty HM, Elsohaby I. Antibacterial and Anti-Biofilm Activities of Cinnamon Oil against Multidrug-Resistant Klebsiella pneumoniae Isolated from Pneumonic Sheep and Goats. Pathogens 2023; 12:1138. [PMID: 37764946 PMCID: PMC10536549 DOI: 10.3390/pathogens12091138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/31/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023] Open
Abstract
The primary objectives were to isolate and identify Klebsiella pneumoniae (K. pneumoniae), and determine the antimicrobial resistance patterns and biofilm formation abilities of the isolates. Additionally, the study aimed to investigate the antimicrobial and anti-biofilm effects of cinnamon oil against K. pneumoniae isolates. A cross-sectional study was conducted from March 2022 to April 2023 to collect 200 samples (including 156 nasal swabs and 44 lung specimens) from pneumonic sheep and goats admitted to the Veterinary Teaching Hospital of Zagazig University, Egypt. K. pneumoniae was isolated from a total of 72 (36%) samples, with 53 (73.6%) isolates recovered from nasal swabs and 19 (26.4%) from lung samples. Among the samples, 52 (36.9%) were from sheep and 20 (33.9%) were from goats. Antimicrobial susceptibility testing of the 72 K. pneumoniae isolates to 18 antimicrobials revealed that all isolates were resistant to ampicillin, amoxicillin/clavulanic acid, cefotaxime, ceftriaxone, tetracycline, colistin, fosfomycin, and trimethoprim/sulphamethoxazole. None of the isolates were resistant to amikacin, imipenem, and norfloxacin. Multidrug resistance (MDR) was observed in all K. pneumoniae isolates recovered from sheep and goats. The average MAR index was 0.71, ranging from 0.50 to 0.83. Regarding biofilm formation, among the K. pneumoniae isolates with a high MAR index (n = 30), 10% exhibited strong formation, 40% showed moderate formation, 43.3% displayed weak formation, and 6.7% did not form biofilms. Additionally, the biofilm-forming genes treC and fimA were present in all 28 biofilm-forming K. pneumoniae isolates, while the mrkA gene was detected in 15 (53.6%) of the 28 isolates. MDR K. pneumoniae isolates with strong biofilm formation abilities were treated with cinnamon oil at varying concentrations (100%, 75%, 50%, and 25%). This treatment resulted in inhibition zone diameters ranging from 35 to 45 mm. Cinnamon oil exhibited lower minimum inhibitory concentration and minimum bactericidal concentration values compared to norfloxacin for all isolates. Additionally, cinnamon oil significantly reduced the expression of biofilm-associated genes (treC, fimA, and mrkA) when compared to isolates treated with norfloxacin or untreated. In conclusion, this study identified a high level of MDR K. pneumoniae with strong and moderate biofilm formation abilities in pneumonic sheep and goats in Sharika Governorate, Egypt. Although cinnamon oil demonstrated potential antibacterial and anti-biofilm properties against K. pneumoniae, further research is required to investigate its effectiveness in treating K. pneumoniae infections in pneumonic sheep and goats.
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Affiliation(s)
- Sara H. Mahrous
- Infectious Diseases, Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig City 44511, Egypt; (S.H.M.); (F.A.E.-B.); (N.Z.A.-Z.); (M.F.E.-M.)
| | - Farouk A. El-Balkemy
- Infectious Diseases, Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig City 44511, Egypt; (S.H.M.); (F.A.E.-B.); (N.Z.A.-Z.); (M.F.E.-M.)
| | - Naser Z. Abo-Zeid
- Infectious Diseases, Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig City 44511, Egypt; (S.H.M.); (F.A.E.-B.); (N.Z.A.-Z.); (M.F.E.-M.)
| | - Mamdouh F. El-Mekkawy
- Infectious Diseases, Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig City 44511, Egypt; (S.H.M.); (F.A.E.-B.); (N.Z.A.-Z.); (M.F.E.-M.)
| | - Hend M. El Damaty
- Infectious Diseases, Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig City 44511, Egypt; (S.H.M.); (F.A.E.-B.); (N.Z.A.-Z.); (M.F.E.-M.)
| | - Ibrahim Elsohaby
- Infectious Diseases, Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig City 44511, Egypt; (S.H.M.); (F.A.E.-B.); (N.Z.A.-Z.); (M.F.E.-M.)
- Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong SAR 999077, China
- Centre for Applied One Health Research and Policy Advice (OHRP), City University of Hong Kong, Hong Kong SAR 999077, China
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Islam OK, Islam I, Saha O, Rahaman MM, Sultana M, Bockmühl DP, Hossain MA. Genomic variability correlates with biofilm phenotypes in multidrug resistant clinical isolates of Pseudomonas aeruginosa. Sci Rep 2023; 13:7867. [PMID: 37188866 DOI: 10.1038/s41598-023-35056-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 05/11/2023] [Indexed: 05/17/2023] Open
Abstract
The multifactorial nature of Pseudomonas aeruginosa biofilm development and genomic variabilities implicates its resistance to conventional antimicrobials and virulence. Therefore, genetic determinants need to be extensively studied to block the early steps of biofilm or already formed biofilms. In this study, a total of 20 multidrug resistant (MDR) clinical P. aeruginosa isolates were evaluated for their biofilm forming abilities and related genes. Of the isolates tested, all of them showed surface attachment tendencies in nutrient limiting conditions, and classified as strong (SBF = 45%), moderate (MBF = 30%) and weak (WBF = 25%) biofilm formers. Complete genome sequencing of representative strong (DMC-27b), moderate (DMC-20c) and weak biofilm former (DMC-30b) isolates was performed. Analysis of biofilm related genes in the sequenced genomes revealed that, 80 of the 88 biofilm related genes possess 98-100% sequence identity to the reference PAO1 strain. Complete and partial sequence data of LecB proteins from tested isolates indicate that isolates containing PA14-like LecB sequences produced strong biofilms. All of the 7 pel operon protein coding genes in weak biofilm former isolate 30b showed significant nucleotide sequence variation with other tested isolates, and their corresponding proteins are 99% identical with the pel operon proteins of PA7. Bioinformatics analyses identified divergent sequence and structural features that separate PA7 like pel operon proteins from reference PAO1-like pel operon. Congo red and pellicle forming assays revealed that the sequence and structure variations may have interfered with the Pel production pathway and resulted in impaired Pel production in isolate 30b that has a PA7 like pel operon. Expression analysis also showed that both pelB and lecB genes were about 5 to 6 folds upregulated after 24 h in SBF 27b in comparison with WBF 30b. Our findings indicate significant genomic divergence in biofilm related genes of P. aeruginosa strains that affect their biofilm phenotypes.
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Affiliation(s)
- Ovinu Kibria Islam
- Department of Microbiology, University of Dhaka, Dhaka, Bangladesh
- Department of Microbiology, Jashore University of Science & Technology, Jashore, Bangladesh
| | - Israt Islam
- Department of Microbiology, University of Dhaka, Dhaka, Bangladesh
- Department of Microbiology, Noakhali University of Science & Technology, Noakhali, Bangladesh
| | - Otun Saha
- Department of Microbiology, University of Dhaka, Dhaka, Bangladesh
- Department of Microbiology, Noakhali University of Science & Technology, Noakhali, Bangladesh
| | | | - Munawar Sultana
- Department of Microbiology, University of Dhaka, Dhaka, Bangladesh
| | - Dirk P Bockmühl
- Faculty of Life Science, Rhine-Waal University of Applied Science, Kleve, Germany
| | - M Anwar Hossain
- Department of Microbiology, University of Dhaka, Dhaka, Bangladesh.
- Department of Microbiology, Jashore University of Science & Technology, Jashore, Bangladesh.
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9
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Juhas M. Multidrug-Resistant Bacteria. BRIEF LESSONS IN MICROBIOLOGY 2023:65-77. [DOI: 10.1007/978-3-031-29544-7_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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10
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GC-MS Analysis and Microbiological Evaluation of Caraway Essential Oil as a Virulence Attenuating Agent against Pseudomonas aeruginosa. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27238532. [PMID: 36500623 PMCID: PMC9741284 DOI: 10.3390/molecules27238532] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/27/2022] [Accepted: 11/30/2022] [Indexed: 12/09/2022]
Abstract
The emergence of resistant microbes threatens public health on our planet, and the emergence of resistant bacteria against the most commonly used antibiotics necessitates urgent alternative therapeutic options. One way to fight resistant microbes is to design new antimicrobial agents, however, this approach takes decades of research. An alternative or parallel approach is to target the virulence of bacteria with natural or synthetic agents. Active constituents from medicinal plants represent a wide library to screen for natural anti-virulence agents. Caraway is used as a traditional spice and in some medicinal applications such as carminative, antispasmodic, appetizer, and expectorant. Caraway essential oil is rich in terpenes that were previously reported to have antimicrobial activities. In our study, we tested the caraway essential oil in sub-inhibitory concentration as a virulence agent against the Gram-negative bacteria Pseudomonas aeruginosa. Caraway essential oil in sub-inhibitory concentration dramatically blocked protease activity, pyocyanin production, biofilm formation, and quorum sensing activity of P. aeruginosa. The gas chromatography-mass spectroscopy (GC-MS) profile of caraway fruit oil identified 13 compounds representing 85.4% of the total oil components with carvone and sylvestrene as the main constituents. In conclusion, caraway essential oil is a promising virulence-attenuating agent that can be used against topical infections caused by P. aeruginosa.
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Grace A, Sahu R, Owen DR, Dennis VA. Pseudomonas aeruginosa reference strains PAO1 and PA14: A genomic, phenotypic, and therapeutic review. Front Microbiol 2022; 13:1023523. [PMID: 36312971 PMCID: PMC9607943 DOI: 10.3389/fmicb.2022.1023523] [Citation(s) in RCA: 67] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 09/28/2022] [Indexed: 11/25/2022] Open
Abstract
Pseudomonas aeruginosa is a ubiquitous, motile, gram-negative bacterium that has been recently identified as a multi-drug resistant pathogen in critical need of novel therapeutics. Of the approximately 5,000 strains, PAO1 and PA14 are common laboratory reference strains, modeling moderately and hyper-virulent phenotypes, respectively. PAO1 and PA14 have been instrumental in facilitating the discovery of novel drug targets, testing novel therapeutics, and supplying critical genomic information on the bacterium. While the two strains have contributed to a wide breadth of knowledge on the natural behaviors and therapeutic susceptibilities of P. aeruginosa, they have demonstrated significant deviations from observations in human infections. Many of these deviations are related to experimental inconsistencies in laboratory strain environment that complicate and, at times, terminate translation from laboratory results to clinical applications. This review aims to provide a comparative analysis of the two strains and potential methods to improve their clinical relevance.
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Affiliation(s)
- Amber Grace
- Department of Biological Sciences, Alabama State University, Montgomery, AL, United States
| | - Rajnish Sahu
- Department of Biological Sciences, Alabama State University, Montgomery, AL, United States
| | | | - Vida A. Dennis
- Department of Biological Sciences, Alabama State University, Montgomery, AL, United States
- *Correspondence: Vida A. Dennis,
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Priyamvada P, Debroy R, Anbarasu A, Ramaiah S. A comprehensive review on genomics, systems biology and structural biology approaches for combating antimicrobial resistance in ESKAPE pathogens: computational tools and recent advancements. World J Microbiol Biotechnol 2022; 38:153. [PMID: 35788443 DOI: 10.1007/s11274-022-03343-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Accepted: 06/21/2022] [Indexed: 12/11/2022]
Abstract
In recent decades, antimicrobial resistance has been augmented as a global concern to public health owing to the global spread of multidrug-resistant strains from different ESKAPE pathogens. This alarming trend and the lack of new antibiotics with novel modes of action in the pipeline necessitate the development of non-antibiotic ways to treat illnesses caused by these isolates. In molecular biology, computational approaches have become crucial tools, particularly in one of the most challenging areas of multidrug resistance. The rapid advancements in bioinformatics have led to a plethora of computational approaches involving genomics, systems biology, and structural biology currently gaining momentum among molecular biologists since they can be useful and provide valuable information on the complex mechanisms of AMR research in ESKAPE pathogens. These computational approaches would be helpful in elucidating the AMR mechanisms, identifying important hub genes/proteins, and their promising targets together with their interactions with important drug targets, which is a crucial step in drug discovery. Therefore, the present review aims to provide holistic information on currently employed bioinformatic tools and their application in the discovery of multifunctional novel therapeutic drugs to combat the current problem of AMR in ESKAPE pathogens. The review also summarizes the recent advancement in the AMR research in ESKAPE pathogens utilizing the in silico approaches.
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Affiliation(s)
- P Priyamvada
- Medical and Biological Computing Laboratory, School of Biosciences and Technology (SBST), Vellore Institute of Technology (VIT), 632014, Vellore, India.,Department of Bio-Sciences, SBST, VIT, 632014, Vellore, India
| | - Reetika Debroy
- Medical and Biological Computing Laboratory, School of Biosciences and Technology (SBST), Vellore Institute of Technology (VIT), 632014, Vellore, India.,Department of Bio-Medical Sciences, SBST, VIT, 632014, Vellore, India
| | - Anand Anbarasu
- Medical and Biological Computing Laboratory, School of Biosciences and Technology (SBST), Vellore Institute of Technology (VIT), 632014, Vellore, India.,Department of Biotechnology, SBST, VIT, 632014, Vellore, India
| | - Sudha Ramaiah
- Medical and Biological Computing Laboratory, School of Biosciences and Technology (SBST), Vellore Institute of Technology (VIT), 632014, Vellore, India. .,Department of Bio-Sciences, SBST, VIT, 632014, Vellore, India. .,School of Biosciences and Technology VIT, 632014, Vellore, Tamil Nadu, India.
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Characterization of Distinct Biofilm Cell Subpopulations and Implications in Quorum Sensing and Antibiotic Resistance. mBio 2022; 13:e0019122. [PMID: 35695457 PMCID: PMC9239111 DOI: 10.1128/mbio.00191-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Bacteria change phenotypically in response to their environment. Free swimming cells transition to biofilm communities that promote cellular cooperativity and resistance to stressors and antibiotics. We uncovered three subpopulations of cells with diverse phenotypes from a single-species Pseudomonas aeruginosa PA14 biofilm, and used a series of steps to isolate, characterize, and map these cell subpopulations in a biofilm. The subpopulations were distinguishable by size and morphology using dynamic light scattering (DLS) and scanning electron microscopy (SEM). Additionally, growth and dispersal of biofilms originating from each cell subpopulation exhibited contrasting responses to antibiotic challenge. Cell subpopulation surface charges were distinctly different, which led us to examine the ionizable surface molecules associated with each subpopulation using mass spectrometry. Matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of cell subpopulations revealed ions unique to each subpopulation of cells that significantly co-localized with ions associated with quorum sensing. Transcript levels of algR, lasR, and rhlI in subpopulations isolated from biofilms differed from levels in planktonic stationary and mid-log cell subpopulations. These studies provide insight into diverse phenotypes, morphologies, and biochemistries of PA14 cell subpopulations for potential applications in combating bacterial pathogenesis, with medical, industrial, and environmental complications.
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14
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Chen X, Ling X, Liu G, Xiao J. Antimicrobial Coating: Tracheal Tube Application. Int J Nanomedicine 2022; 17:1483-1494. [PMID: 35378882 PMCID: PMC8976493 DOI: 10.2147/ijn.s353071] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 03/21/2022] [Indexed: 12/13/2022] Open
Abstract
Ventilator-associated pneumonia (VAP) is a common and serious nosocomial infection in mechanically ventilated patients, increasing mortality, prolonging the patient length of stay, and increasing costs. In recent years, extensive studies on ventilator-associated pneumonia have shown that tracheal intubation plays an essential role in the pathogenesis of VAP, with the primary mechanism being the rapid colonization of the tracheal intubation surface by microbiota. Antibiotics do not combat microbial airway colonization, and antimicrobial coating materials offer new ideas to solve this problem. This paper reviews the current research progress on the role of endotracheal tube (ET) biofilms in the pathogenesis of VAP and antimicrobial coating materials.
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Affiliation(s)
- Xuemeng Chen
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Xiaomei Ling
- Department of Anesthesiology, Guangdong Provincial People’s Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong, People’s Republic of China
| | - Gaowang Liu
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
| | - Jinfang Xiao
- Department of Anesthesiology, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, People’s Republic of China
- Correspondence: Jinfang Xiao, Department of Anaesthesiology, Nanfang Hospital, Southern Medical University, Jingxi Street, Guangzhou, 510515, Guangdong, People’s Republic of China, Tel +86 198 6518 2069, Email
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15
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Biofilm Formation and Associated Gene Expression in Multidrug-Resistant Klebsiella pneumoniae Isolated from Clinical Specimens. Curr Microbiol 2022; 79:73. [PMID: 35084583 DOI: 10.1007/s00284-022-02766-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 01/12/2022] [Indexed: 01/01/2023]
Abstract
Biofilms reduce the bacterial growth rate, inhibit antibiotic penetration, lead to the development of persister cells and facilitate genetic exchange. The biofilm-associated Klebsiella pneumoniae infections have not been well studied, and their implications in overcoming the effects of antimicrobial therapy are yet to be fully understood. Hence this study evaluated the antibiotic resistance pattern, antibiotic resistance determinants of extended-spectrum beta-lactamase (ESBL) family. Biofilm-forming ability of seventy multidrug-resistant clinical isolates of K. pneumoniae and the biofilm-associated genes of representative biofilm formers from a tertiary care hospital were also assessed. The K. pneumoniae isolated from urine exhibited resistance towards ceftazidime, nalidixic acid and meropenem. Isolates from blood were resistant to cefuroxime. Higher rates of resistance were observed towards cefuroxime, nalidixic acid, and meropenem for the isolates from the endotracheal aspirate. Extended spectrum beta-lactamase production by CLSI's disc diffusion-based confirmation test revealed all the K. pneumoniae to be as ESBL producers. Most of the isolates harboured the bla gene variants, blaSHV and blaTEM. Majority of the isolates were colistin sensitive. 97.1% of the K. pneumoniae produced biofilm. K. pneumoniae isolated from pus and blood produced fully established biofilms. Strong biofilm formers were sensitive to co-trimoxazole and ciprofloxacin. Moderate biofilm formers exhibited sensitivity towards meropenem and imipenem. Expression of the fimH gene was increased, while mrkD showed reduced expression among the strong biofilm formers. Moderate biofilm formers showed variable expression of the genes associated with the biofilm formation. The weak and non-biofilm formers showed reduced expression of both the fimbrial genes. Multidrug-resistant isolates produced ESBLs and formed well-established biofilms.
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Laborda P, Hernando-Amado S, Martínez JL, Sanz-García F. Antibiotic Resistance in Pseudomonas. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1386:117-143. [DOI: 10.1007/978-3-031-08491-1_5] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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Kakkar A, Verma RK, Samal B, Chatterjee S. Interplay between the cyclic di-GMP network and the cell-cell signalling components coordinates virulence-associated functions in Xanthomonas oryzae pv. oryzae. Environ Microbiol 2021; 23:5433-5462. [PMID: 34240791 DOI: 10.1111/1462-2920.15664] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 07/06/2021] [Indexed: 11/29/2022]
Abstract
Xanthomonas oryzae pv. oryzae (Xoo) causes a serious disease of rice known as bacterial leaf blight. Several virulence-associated functions have been characterized in Xoo. However, the role of important second messenger c-di-GMP signalling in the regulation of virulence-associated functions still remains elusive in this phytopathogen. In this study we have performed an investigation of 13 c-di-GMP modulating deletion mutants to understand their contribution in Xoo virulence and lifestyle transition. We show that four Xoo proteins, Xoo2331, Xoo2563, Xoo2860 and Xoo2616, are involved in fine-tuning the in vivo c-di-GMP abundance and also play a role in the regulation of virulence-associated functions. We have further established the importance of the GGDEF domain of Xoo2563, a previously characterized c-di-GMP phosphodiesterase, in the virulence-associated functions of Xoo. Interestingly the strain harbouring the GGDEF domain deletion (ΔXoo2563GGDEF ) exhibited EPS deficiency and hypersensitivity to streptonigrin, indicative of altered iron metabolism. This is in contrast to the phenotype exhibited by an EAL overexpression strain wherein, the ΔXoo2563GGDEF exhibited other phenotypes, similar to the strain overexpressing the EAL domain. Taken together, our results indicate a complex interplay of c-di-GMP signalling with the cell-cell signalling to coordinate virulence-associated function in Xoo.
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Affiliation(s)
- Akanksha Kakkar
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
| | - Raj Kumar Verma
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
| | - Biswajit Samal
- Centre for DNA Fingerprinting and Diagnostics, Uppal, Hyderabad, 500039, India.,Graduate Studies, Manipal Academy of Higher Education, Mangalore, Karnataka, 576104, India
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18
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Gao C, Zhang L, Wang J, Jin M, Tang Q, Chen Z, Cheng Y, Yang R, Zhao G. Electrospun nanofibers promote wound healing: theories, techniques, and perspectives. J Mater Chem B 2021; 9:3106-3130. [PMID: 33885618 DOI: 10.1039/d1tb00067e] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
At present, the clinical strategies for treating chronic wounds are limited, especially when it comes to pain relief and rapid wound healing. Therefore, there is an urgent need to develop alternative treatment methods. This paper provides a systematic review on recent researches on how electrospun nanofiber scaffolds promote wound healing and how the electrospinning technology has been used for fabricating multi-dimensional, multi-pore and multi-functional nanofiber scaffolds that have greatly promoted the development of wound healing dressings. First, we provide a review on the four stages of wound healing, which is followed by a discussion on the evolvement of the electrospinning technology, what is involved in electrospinning devices, and factors affecting the electrospinning process. Finally, we present the possible mechanisms of electrospun nanofibers to promote wound healing, the classification of electrospun polymers, cell infiltration favoring fiber scaffolds, antibacterial fiber scaffolds, and future multi-functional scaffolds. Although nanofiber scaffolds have made great progress as a type of multi-functional biomaterial, major challenges still remain for commercializing them in a way that fully meets the needs of patients.
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Affiliation(s)
- Chen Gao
- College of Life Sciences, Anhui Medical University, Hefei 230022, Anhui, China
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19
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O'Banion BS, O'Neal L, Alexandre G, Lebeis SL. Bridging the Gap Between Single-Strain and Community-Level Plant-Microbe Chemical Interactions. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2020; 33:124-134. [PMID: 31687914 DOI: 10.1094/mpmi-04-19-0115-cr] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Although the influence of microbiomes on the health of plant hosts is evident, specific mechanisms shaping the structure and dynamics of microbial communities in the phyllosphere and rhizosphere are only beginning to become clear. Traditionally, plant-microbe interactions have been studied using cultured microbial isolates and plant hosts but the rising use of 'omics tools provides novel snapshots of the total complex community in situ. Here, we discuss the recent advances in tools and techniques used to monitor plant-microbe interactions and the chemical signals that influence these relationships in above- and belowground tissues. Particularly, we highlight advances in integrated microscopy that allow observation of the chemical exchange between individual plant and microbial cells, as well as high-throughput, culture-independent approaches to investigate the total genetic and metabolic contribution of the community. The chemicals discussed have been identified as relevant signals across experimental spectrums. However, mechanistic insight into the specific interactions mediated by many of these chemicals requires further testing. Experimental designs that attempt to bridge the gap in biotic complexity between single strains and whole communities will advance our understanding of the chemical signals governing plant-microbe associations in the rhizosphere and phyllosphere.
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Affiliation(s)
- Bridget S O'Banion
- Department of Microbiology, University of Tennessee, Knoxville, TN, U.S.A
| | - Lindsey O'Neal
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee
| | - Gladys Alexandre
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee
| | - Sarah L Lebeis
- Department of Microbiology, University of Tennessee, Knoxville, TN, U.S.A
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20
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Lahiri D, Dash S, Dutta R, Nag M. Elucidating the effect of anti-biofilm activity of bioactive compounds extracted from plants. J Biosci 2019; 44:52. [PMID: 31180065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Affiliation(s)
- Dibyajit Lahiri
- Department of Biotechnology, University of Engineering and Management, Kolkata, India
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22
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Loss of the Two-Component System TctD-TctE in Pseudomonas aeruginosa Affects Biofilm Formation and Aminoglycoside Susceptibility in Response to Citric Acid. mSphere 2019; 4:4/2/e00102-19. [PMID: 30842268 PMCID: PMC6403454 DOI: 10.1128/msphere.00102-19] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The two-component system TctD-TctE is important for regulating the uptake of tricarboxylic acids in Pseudomonas aeruginosa TctD-TctE accomplishes this through derepression of the gene opdH, which encodes a tricarboxylic acid-specific porin. Previous work from our lab revealed that TctD-TctE in P. aeruginosa also has a role in resistance to aminoglycoside antibiotics. The aim of this study was to further characterize the role of TctD-TctE in P. aeruginosa in the presence of citric acid. Here it was found that deletion of P. aeruginosa PA14 TctD-TctE (ΔtctED) resulted in a 4-fold decrease in the biofilm bactericidal concentrations of the aminoglycosides tobramycin and gentamicin when citric acid was present in nutrient media. Tobramycin accumulation assays demonstrated that deletion of TctD-TctE resulted in an increase in the amount of tobramycin retained in biofilm cells. The PA14 wild type responded to increasing concentrations of citric acid by producing less biofilm. In contrast, the amount of ΔtctED mutant biofilm formation remained constant or enhanced. Furthermore, the ΔtctED strain was incapable of growing on citric acid as a sole carbon source and was highly reduced in its ability to grow in the presence of citric acid even when an additional carbon source was available. Use of phenotypic and genetic microarrays found that this growth deficiency of the ΔtctED mutant is unique to citric acid and that multiple metabolic genes are dysregulated. This work demonstrates that TctD-TctE in P. aeruginosa has a role in biofilm development that is dependent on citric acid and that is separate from the previously characterized involvement in resistance to antibiotics.IMPORTANCE Nutrient availability is an important contributor to the ability of bacteria to establish successful infections in a host. Pseudomonas aeruginosa is an opportunistic pathogen in humans causing infections that are difficult to treat. In part, its success is attributable to a high degree of metabolic versatility. P. aeruginosa is able to sense and respond to varied and limited nutrient stress in the host environment. Two-component systems are important sensors-regulators of cellular responses to environmental stresses, such as those encountered in the host. This work demonstrates that the response by the two-component system TctD-TctE to the presence of citric acid has a role in biofilm formation, aminoglycoside susceptibility, and growth in P. aeruginosa.
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Pse-T2, an Antimicrobial Peptide with High-Level, Broad-Spectrum Antimicrobial Potency and Skin Biocompatibility against Multidrug-Resistant Pseudomonas aeruginosa Infection. Antimicrob Agents Chemother 2018; 62:AAC.01493-18. [PMID: 30323036 DOI: 10.1128/aac.01493-18] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/30/2018] [Indexed: 02/06/2023] Open
Abstract
Pseudin-2, isolated from the frog Pseudis paradoxa, exhibits potent antibacterial activity but also cytotoxicity. In an effort to develop clinically applicable antimicrobial peptides (AMPs), we designed pseudin-2 analogs with Lys substitutions, resulting in elevated amphipathic α-helical structure and cationicity. In addition, truncated analogs of pseudin-2 and Lys-substituted peptides were synthesized to produce linear 18-residue amphipathic α-helices, which were further investigated for their mechanism and functions. These truncated analogs exhibited higher antimicrobial activity and lower cytotoxicity than pseudin-2. In particular, Pse-T2 showed marked pore formation, permeabilization of the outer/inner bacterial membranes, and DNA binding. Fluorescence spectroscopy and scanning electron microscopy showed that Pse-T2 kills bacterial cells by disrupting membrane integrity. In vivo, wounds infected with multidrug-resistant (MDR) Pseudomonas aeruginosa healed significantly faster when treated with Pse-T2 than did untreated wounds or wounds treated with ciprofloxacin. Moreover, Pse-T2 facilitated infected-wound closure by reducing inflammation through suppression of interleukin-1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α). These data suggest that the small antimicrobial peptide Pse-T2 could be useful for future development of therapeutic agents effective against MDR bacterial strains.
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Pseudomonas aeruginosa type IV minor pilins and PilY1 regulate virulence by modulating FimS-AlgR activity. PLoS Pathog 2018; 14:e1007074. [PMID: 29775484 PMCID: PMC5979040 DOI: 10.1371/journal.ppat.1007074] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 05/31/2018] [Accepted: 05/04/2018] [Indexed: 11/19/2022] Open
Abstract
Type IV pili are expressed by a wide range of prokaryotes, including the opportunistic pathogen Pseudomonas aeruginosa. These flexible fibres mediate twitching motility, biofilm maturation, surface adhesion, and virulence. The pilus is composed mainly of major pilin subunits while the low abundance minor pilins FimU-PilVWXE and the putative adhesin PilY1 prime pilus assembly and are proposed to form the pilus tip. The minor pilins and PilY1 are encoded in an operon that is positively regulated by the FimS-AlgR two-component system. Independent of pilus assembly, PilY1 was proposed to be a mechanosensory component that—in conjunction with minor pilins—triggers up-regulation of acute virulence phenotypes upon surface attachment. Here, we investigated the link between the minor pilins/PilY1 and virulence. pilW, pilX, and pilY1 mutants had reduced virulence towards Caenorhabditis elegans relative to wild type or a major pilin mutant, implying a role in pathogenicity that is independent of pilus assembly. We hypothesized that loss of specific minor pilins relieves feedback inhibition on FimS-AlgR, increasing transcription of the AlgR regulon and delaying C. elegans killing. Reporter assays confirmed that FimS-AlgR were required for increased expression of the minor pilin operon upon loss of select minor pilins. Overexpression of AlgR or its hyperactivation via a phosphomimetic mutation reduced virulence, and the virulence defects of pilW, pilX, and pilY1 mutants required FimS-AlgR expression and activation. We propose that PilY1 and the minor pilins inhibit their own expression, and that loss of these proteins leads to FimS-mediated activation of AlgR that suppresses expression of acute-phase virulence factors and delays killing. This mechanism could contribute to adaptation of P. aeruginosa in chronic lung infections, as mutations in the minor pilin operon result in the loss of piliation and increased expression of AlgR-dependent virulence factors–such as alginate–that are characteristic of such infections. Pseudomonas aeruginosa causes dangerous infections, including chronic lung infections in cystic fibrosis patients. It uses many strategies to infect its hosts, including deployment of grappling hook-like fibres called type IV pili. Among the components involved in assembly and function of the pilus are five proteins called minor pilins that—along with a larger protein called PilY1—may help the pilus attach to surfaces. In a roundworm infection model, loss of PilY1 and specific minor pilins delayed killing, while loss of other pilus components did not. We traced this effect to increased activation of the FimS-AlgR regulatory system that inhibits the expression of virulence factors used early in infection, while positively regulating chronic infection traits such as alginate production, a phenotype called mucoidy. A disruption in the appropriate timing of FimS-AlgR-dependent virulence factor expression when select minor pilins or PilY1 are missing may explain why those pilus-deficient mutants have reduced virulence compared with others whose products are not under FimS-AlgR control. Increased FimS-AlgR activity upon loss of PilY1 and specific minor pilins could help to explain the frequent co-occurrence of the non-piliated and mucoid phenotypes that are hallmarks of chronic P. aeruginosa lung infections.
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Pseudomonas aeruginosa Biofilm Antibiotic Resistance Gene ndvB Expression Requires the RpoS Stationary-Phase Sigma Factor. Appl Environ Microbiol 2018; 84:AEM.02762-17. [PMID: 29352081 DOI: 10.1128/aem.02762-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 01/11/2018] [Indexed: 01/21/2023] Open
Abstract
Chronic, biofilm-based bacterial infections are exceptionally difficult to eradicate due to the high degree of antibiotic recalcitrance exhibited by cells in biofilm communities. In the opportunistic pathogen Pseudomonas aeruginosa, biofilm recalcitrance is multifactorial and arises in part from the preferential expression of resistance genes in biofilms compared to exponential-phase planktonic cells. One such mechanism involves ndvB, which we have previously shown to be expressed specifically in biofilms. In this study, we investigated the regulatory basis of this lifestyle-specific expression by developing an unstable green fluorescent protein (GFP) transcriptional reporter to observe the expression pattern of ndvB We found that in addition to its expression in biofilms, ndvB was upregulated in planktonic cells as they enter stationary phase. The transcription of ndvB in both growth phases was shown to be dependent on the stationary-phase sigma factor RpoS, and mutation of a putative RpoS binding site in the ndvB promoter abolished the activity of the promoter in stationary-phase cells. Overall, we have expanded our understanding of the temporal expression of ndvB in P. aeruginosa and have uncovered a regulatory basis for its growth phase-dependent expression.IMPORTANCE Bacterial biofilms are more resistant to antibiotics than free-living planktonic cells, and understanding the mechanistic basis of this resistance can inform treatments of biofilm-based infections. In addition to chemical and structural barriers that can inhibit antibiotic entry, the upregulation of specific genes in biofilms contributes to the resistance. We investigated this biofilm-specific gene induction by examining expression patterns of ndvB, a gene involved in biofilm resistance of the opportunistic pathogen Pseudomonas aeruginosa We characterized ndvB expression in planktonic and biofilm growth conditions with an unstable green fluorescent protein (GFP) reporter and found that the expression of ndvB in biofilms is dependent on the stationary-phase sigma factor RpoS. Overall, our results support the physiological similarity between biofilms and stationary-phase cells and suggest that the induction of some stationary-phase genes in biofilms may contribute to their increased antibiotic resistance.
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Skariyachan S, Sridhar VS, Packirisamy S, Kumargowda ST, Challapilli SB. Recent perspectives on the molecular basis of biofilm formation by Pseudomonas aeruginosa and approaches for treatment and biofilm dispersal. Folia Microbiol (Praha) 2018; 63:413-432. [PMID: 29352409 DOI: 10.1007/s12223-018-0585-4] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Accepted: 01/12/2018] [Indexed: 12/25/2022]
Abstract
Pseudomonas aeruginosa, a Gram-negative, rod-shaped bacterium causes widespread diseases in humans. This bacterium is frequently related to nosocomial infections such as pneumonia, urinary tract infections (UTIs) and bacteriaemia especially in immunocompromised patients. The current review focuses on the recent perspectives on biofilms formation by these bacteria. Biofilms are communities of microorganisms in which cells stick to each other and often adhere to a surface. These adherent cells are usually embedded within a self-produced matrix of extracellular polymeric substance (EPS). Pel, psl and alg operons present in P. aeruginosa are responsible for the biosynthesis of extracellular polysaccharide which plays an important role in cell surface interactions during biofilm formation. Recent studies suggested that cAMP signalling pathway, quorum-sensing pathway, Gac/Rsm pathway and c-di-GMP signalling pathway are the main mechanism that leads to the biofilm formation. Understanding the bacterial virulence depends on a number of cell-associated and extracellular factors and is very essential for the development of potential drug targets. Thus, the review focuses on the major genes involved in the biofilm formation, the state of art update on the biofilm treatment and the dispersal approaches such as targeting adhesion and maturation, targeting virulence factors and other strategies such as small molecule-based inhibitors, phytochemicals, bacteriophage therapy, photodynamic therapy, antimicrobial peptides and natural therapies and vaccines to curtail the biofilm formation by P. aeruginosa.
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Affiliation(s)
- Sinosh Skariyachan
- Department of Biotechnology, R & D Centre, Dayananda Sagar College of Engineering, Bangalore, Karnataka, 560 078, India.
| | - Vaishnavi Sneha Sridhar
- Department of Biotechnology, R & D Centre, Dayananda Sagar College of Engineering, Bangalore, Karnataka, 560 078, India
| | - Swathi Packirisamy
- Department of Biotechnology, R & D Centre, Dayananda Sagar College of Engineering, Bangalore, Karnataka, 560 078, India
| | - Supreetha Toplar Kumargowda
- Department of Biotechnology, R & D Centre, Dayananda Sagar College of Engineering, Bangalore, Karnataka, 560 078, India
| | - Sneha Basavaraj Challapilli
- Department of Biotechnology, R & D Centre, Dayananda Sagar College of Engineering, Bangalore, Karnataka, 560 078, India
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Hall CW, Mah TF. Molecular mechanisms of biofilm-based antibiotic resistance and tolerance in pathogenic bacteria. FEMS Microbiol Rev 2018; 41:276-301. [PMID: 28369412 DOI: 10.1093/femsre/fux010] [Citation(s) in RCA: 972] [Impact Index Per Article: 138.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 02/22/2017] [Indexed: 02/06/2023] Open
Abstract
Biofilms are surface-attached groups of microbial cells encased in an extracellular matrix that are significantly less susceptible to antimicrobial agents than non-adherent, planktonic cells. Biofilm-based infections are, as a result, extremely difficult to cure. A wide range of molecular mechanisms contribute to the high degree of recalcitrance that is characteristic of biofilm communities. These mechanisms include, among others, interaction of antimicrobials with biofilm matrix components, reduced growth rates and the various actions of specific genetic determinants of antibiotic resistance and tolerance. Alone, each of these mechanisms only partially accounts for the increased antimicrobial recalcitrance observed in biofilms. Acting in concert, however, these defences help to ensure the survival of biofilm cells in the face of even the most aggressive antimicrobial treatment regimens. This review summarises both historical and recent scientific data in support of the known biofilm resistance and tolerance mechanisms. Additionally, suggestions for future work in the field are provided.
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Targeting the alternative sigma factor RpoN to combat virulence in Pseudomonas aeruginosa. Sci Rep 2017; 7:12615. [PMID: 28974743 PMCID: PMC5626770 DOI: 10.1038/s41598-017-12667-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Accepted: 09/18/2017] [Indexed: 12/22/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative, opportunistic pathogen that infects immunocompromised and cystic fibrosis patients. Treatment is difficult due to antibiotic resistance, and new antimicrobials are needed to treat infections. The alternative sigma factor 54 (σ54, RpoN), regulates many virulence-associated genes. Thus, we evaluated inhibition of virulence in P. aeruginosa by a designed peptide (RpoN molecular roadblock, RpoN*) which binds specifically to RpoN consensus promoters. We expected that RpoN* binding to its consensus promoter sites would repress gene expression and thus virulence by blocking RpoN and/or other transcription factors. RpoN* reduced transcription of approximately 700 genes as determined by microarray analysis, including genes related to virulence. RpoN* expression significantly reduced motility, protease secretion, pyocyanin and pyoverdine production, rhamnolipid production, and biofilm formation. Given the effectiveness of RpoN* in vitro, we explored its effects in a Caenorhabditis elegans–P. aeruginosa infection model. Expression of RpoN* protected C. elegans in a paralytic killing assay, whereas worms succumbed to paralysis and death in its absence. In a slow killing assay, which mimics establishment and proliferation of an infection, C. elegans survival was prolonged when RpoN* was expressed. Thus, blocking RpoN consensus promoter sites is an effective strategy for abrogation of P. aeruginosa virulence.
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Saffari M, Karami S, Firoozeh F, Sehat M. Evaluation of biofilm-specific antimicrobial resistance genes in Pseudomonas aeruginosa isolates in Farabi Hospital. J Med Microbiol 2017; 66:905-909. [DOI: 10.1099/jmm.0.000521] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Mahmood Saffari
- Department of Microbiology, School of Medicine‚ Kashan University of Medical Sciences, Kashan, Iran
| | - Shabnam Karami
- Department of Microbiology, School of Medicine‚ Kashan University of Medical Sciences, Kashan, Iran
| | - Farzaneh Firoozeh
- Department of Microbiology, School of Medicine‚ Kashan University of Medical Sciences, Kashan, Iran
| | - Mojtaba Sehat
- Trauma Research Center, Kashan University of Medical Sciences, Kashan, Iran
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Restructuring of Enterococcus faecalis biofilm architecture in response to antibiotic-induced stress. NPJ Biofilms Microbiomes 2017; 3:15. [PMID: 28685097 PMCID: PMC5493694 DOI: 10.1038/s41522-017-0023-4] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 05/31/2017] [Accepted: 06/09/2017] [Indexed: 12/19/2022] Open
Abstract
Bacterial biofilms are intrinsically resistant to antimicrobial treatment, which contributes to microbial persistence in clinical infections. Enterococcus faecalis is an opportunistic pathogen that readily forms biofilms and is the most prevalent enterococcal species identified in healthcare-associated infections. Since intrinsic resistance to multiple antibiotics is common for enterococci, and antibiotic resistance is elevated in biofilm populations, it is imperative to understand the mechanisms involved. Previously, we identified two glycosyltransferase genes whose disruption resulted in impaired nascent biofilm formation in the presence of antibiotic concentrations subinhibitory for parent growth and biofilm formation. The glycosyltransferases are involved in synthesis of the cell-wall-associated rhamnopolysaccharide Epa. Here we examined the effect of epa mutations on the temporal development of E. faecalis biofilms, and on the effects of antibiotics on pre-formed biofilms using scanning electron microscopy. We show that ΔepaOX mutant cells arrange into complex multidimensional biofilms independent of antibiotic exposure, while parent cells form biofilms that are monolayers in the absence of antibiotics. Remarkably, upon exposure to antibiotics parent biofilm cells restructure into complex three-dimensional biofilms resembling those of the ΔepaOX mutant without antibiotics. All biofilms exhibiting complex cellular architectures were less structurally stable than monolayer biofilms, with the biofilm cells exhibiting increased detachment. Our results indicate that E. faecalis biofilms restructure in response to cellular stress whether induced by antibiotics in the case of parent cells, or by deficiencies in Epa composition for the ΔepaOX strain. The data demonstrate a link between cellular architecture and antibiotic resistance of E. faecalis biofilms. Studying how the architecture of bacterial biofilms can change on exposure to antibiotics could help tackle persistent clinical infections. Enterococcus faecalis is one of the most prevalent bacteria involved in healthcare situations. Its resistance to antibiotics is elevated by the formation of biofilms. Gary Dunny and colleagues at the University of Minnesota, USA studied genetic factors related to the response of E. faecalis biofilms to antibiotics. They identified mutations that caused the bacterial cells to produce structurally altered biofilms and found that similar structural alterations were induced in biofilms made by normal cells in the presence of antibiotics. The altered architecture can make the biofilms less stable and therefore more easily disrupted by treatments. Learning more about the mechanisms underlying these structural changes in biofilms might lead to new options in treating antibiotic resistant infections.
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Gawin A, Valla S, Brautaset T. The XylS/Pm regulator/promoter system and its use in fundamental studies of bacterial gene expression, recombinant protein production and metabolic engineering. Microb Biotechnol 2017; 10:702-718. [PMID: 28276630 PMCID: PMC5481539 DOI: 10.1111/1751-7915.12701] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 02/04/2017] [Accepted: 02/07/2017] [Indexed: 12/21/2022] Open
Abstract
The XylS/Pm regulator/promoter system originating from the Pseudomonas putida TOL plasmid pWW0 is widely used for regulated low‐ and high‐level recombinant expression of genes and gene clusters in Escherichia coli and other bacteria. Induction of this system can be graded by using different cheap benzoic acid derivatives, which enter cells by passive diffusion, operate in a dose‐dependent manner and are typically not metabolized by the host cells. Combinatorial mutagenesis and selection using the bla gene encoding β‐lactamase as a reporter have demonstrated that the Pm promoter, the DNA sequence corresponding to the 5′ untranslated end of its cognate mRNA and the xylS coding region can be modified and improved relative to various types of applications. By combining such mutant genetic elements, altered and extended expression profiles were achieved. Due to their unique properties, obtained systems serve as a genetic toolbox valuable for heterologous protein production and metabolic engineering, as well as for basic studies aiming at understanding fundamental parameters affecting bacterial gene expression. The approaches used to modify XylS/Pm should be adaptable for similar improvements also of other microbial expression systems. In this review, we summarize constructions, characteristics, refinements and applications of expression tools using the XylS/Pm system.
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Affiliation(s)
- Agnieszka Gawin
- Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Svein Valla
- Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
| | - Trygve Brautaset
- Department of Biotechnology, Norwegian University of Science and Technology, Trondheim, Norway
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Bacterial Lysis through Interference with Peptidoglycan Synthesis Increases Biofilm Formation by Nontypeable Haemophilus influenzae. mSphere 2017; 2:mSphere00329-16. [PMID: 28124027 PMCID: PMC5244263 DOI: 10.1128/msphere.00329-16] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 12/31/2016] [Indexed: 11/20/2022] Open
Abstract
Most, if not all, bacteria form a biofilm, a multicellular structure that protects them from antimicrobial actions of the host immune system and affords resistance to antibiotics. The latter is especially disturbing with the increase in multiresistant bacterial clones worldwide. Bacterial biofilm formation is a multistep process that starts with surface adhesion, after which attached bacteria divide and give rise to biomass. The actual steps required for Haemophilus influenzae biofilm formation are largely not known. We show that interference with peptidoglycan biosynthesis increases biofilm formation because of the release of bacterial genomic DNA. Subinhibitory concentrations of β-lactam antibiotics, which are often prescribed to treat H. influenzae infections, increase biofilm formation through a similar mechanism. Therefore, when β-lactam antibiotics do not reach their MIC in vivo, they might not only drive selection for β-lactam-resistant clones but also increase biofilm formation and resistance to other antimicrobial compounds. Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that mainly causes otitis media in children and community-acquired pneumonia or exacerbations of chronic obstructive pulmonary disease in adults. A large variety of studies suggest that biofilm formation by NTHi may be an important step in the pathogenesis of this bacterium. However, the underlying mechanisms involved in this process are poorly elucidated. In this study, we used a transposon mutant library to identify bacterial genes involved in biofilm formation. The growth and biofilm formation of 4,172 transposon mutants were determined, and the involvement of the identified genes in biofilm formation was validated in in vitro experiments. Here, we present experimental data showing that increased bacterial lysis, through interference with peptidoglycan synthesis, results in elevated levels of extracellular DNA, which increased biofilm formation. Interestingly, similar results were obtained with subinhibitory concentrations of β-lactam antibiotics, known to interfere with peptidoglycan synthesis, but such an effect does not appear with other classes of antibiotics. These results indicate that treatment with β-lactam antibiotics, especially for β-lactam-resistant NTHi isolates, might increase resistance to antibiotics by increasing biofilm formation. IMPORTANCE Most, if not all, bacteria form a biofilm, a multicellular structure that protects them from antimicrobial actions of the host immune system and affords resistance to antibiotics. The latter is especially disturbing with the increase in multiresistant bacterial clones worldwide. Bacterial biofilm formation is a multistep process that starts with surface adhesion, after which attached bacteria divide and give rise to biomass. The actual steps required for Haemophilus influenzae biofilm formation are largely not known. We show that interference with peptidoglycan biosynthesis increases biofilm formation because of the release of bacterial genomic DNA. Subinhibitory concentrations of β-lactam antibiotics, which are often prescribed to treat H. influenzae infections, increase biofilm formation through a similar mechanism. Therefore, when β-lactam antibiotics do not reach their MIC in vivo, they might not only drive selection for β-lactam-resistant clones but also increase biofilm formation and resistance to other antimicrobial compounds.
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Valadbeigi H, Sadeghifard N, Salehi MB. Assessment of biofilm formation in Pseudomonas aeruginosa by antisense mazE-PNA. Microb Pathog 2017; 104:28-31. [PMID: 28062294 DOI: 10.1016/j.micpath.2017.01.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Revised: 12/28/2016] [Accepted: 01/02/2017] [Indexed: 01/22/2023]
Abstract
The hallmark patogenicity in Pseudomonas aeruginosa (P. aeruginosa) is biofilm formation that is not easy to eradicate, because it has variety mechanisms for antibiotic resistance. In addition, toxin-antitoxin (TA) system may play role in biofilm formation. The current study aimed to evaluate the role of TA loci in biofilm formation. Therefore, 18 P. aeruginosa clinical isolates were collected and evaluated for specific biofilm and TA genes. The analysis by RT-qPCR demonstrated that expression of mazE antitoxin in biofilm formation was increase. On the other hand, mazE antitoxin TA system was used as target for antisense PNA. mazE-PNA was able to influence in biofilm formation and was inhibit at 5,10 and 15 μM concentrations biofilm formation in P. aeruginosa. Therefore, it could be highlighted target for anti-biofilm target to eradicate P. aeruginosa biofilm producer.
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Affiliation(s)
- Hassan Valadbeigi
- Department of Microbiology, Science and Research Branch, Islamic Azad University, Fars, Iran; Department of Microbiology, Shiraz Branch, Islamic Azad University, Shiraz, Iran.
| | - Nourkhoda Sadeghifard
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.
| | - Majid Baseri Salehi
- Department of Microbiology, Kazeroun Branch, Islamic Azad University, Kazeroun, Iran.
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Qi L, Li H, Zhang C, Liang B, Li J, Wang L, Du X, Liu X, Qiu S, Song H. Relationship between Antibiotic Resistance, Biofilm Formation, and Biofilm-Specific Resistance in Acinetobacter baumannii. Front Microbiol 2016; 7:483. [PMID: 27148178 PMCID: PMC4828443 DOI: 10.3389/fmicb.2016.00483] [Citation(s) in RCA: 225] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Accepted: 03/22/2016] [Indexed: 01/09/2023] Open
Abstract
In this study, we aimed to examine the relationships between antibiotic resistance, biofilm formation, and biofilm-specific resistance in clinical isolates of Acinetobacter baumannii. The tested 272 isolates were collected from several hospitals in China during 2010–2013. Biofilm-forming capacities were evaluated using the crystal violet staining method. Antibiotic resistance/susceptibility profiles to 21 antibiotics were assessed using VITEK 2 system, broth microdilution method or the Kirby-Bauer disc diffusion method. The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) to cefotaxime, imipenem, and ciprofloxacin were evaluated using micro dilution assays. Genetic relatedness of the isolates was also analyzed by pulsed-field gel electrophoresis (PFGE) and plasmid profile. Among all the 272 isolates, 31 were multidrug-resistant (MDR), and 166 were extensively drug-resistant (XDR). PFGE typing revealed 167 pattern types and 103 clusters with a similarity of 80%. MDR and XDR isolates built up the main prevalent genotypes. Most of the non-MDR isolates were distributed in a scattered pattern. Additionally, 249 isolates exhibited biofilm formation, among which 63 were stronger biofilm formers than type strain ATCC19606. Population that exhibited more robust biofilm formation likely contained larger proportion of non-MDR isolates. Isolates with higher level of resistance tended to form weaker biofilms. The MBECs for cefotaxime, imipenem, and ciprofloxacin showed a positive correlation with corresponding MICs, while the enhancement in resistance occurred independent of the quantity of biofilm biomass produced. Results from this study imply that biofilm acts as a mechanism for bacteria to get a better survival, especially in isolates with resistance level not high enough. Moreover, even though biofilms formed by isolates with high level of resistance are always weak, they could still provide similar level of protection for the isolates. Further explorations genetically would improve our understanding of these processes and provide novel insights in the therapeutics and prevention against A. baumannii biofilm-related infections.
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Affiliation(s)
- Lihua Qi
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Hao Li
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Chuanfu Zhang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Beibei Liang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Jie Li
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Ligui Wang
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Xinying Du
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Xuelin Liu
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Shaofu Qiu
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
| | - Hongbin Song
- Department of Infectious Disease Control, Institute of Disease Control and Prevention, Academy of Military Medical Sciences Beijing, China
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Major Transcriptome Changes Accompany the Growth of Pseudomonas aeruginosa in Blood from Patients with Severe Thermal Injuries. PLoS One 2016; 11:e0149229. [PMID: 26933952 PMCID: PMC4774932 DOI: 10.1371/journal.pone.0149229] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/04/2016] [Indexed: 11/19/2022] Open
Abstract
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen that causes serious infections in immunocompromised hosts including severely burned patients. After multiplying within the burn wound, P. aeruginosa translocate into the bloodstream causing bacterial sepsis frequently leading to organ dysfunction and septic shock. Although the pathogenesis of P. aeruginosa infection of thermally-injured wounds has been extensively analyzed, little is known regarding the ability of P. aeruginosa to adapt and survive within the blood of severely burned patients during systemic infection. To identify such adaptations, transcriptome analyses (RNA-seq) were conducted on P. aeruginosa strain PA14 that was grown in whole blood from a healthy volunteer or three severely burned patients. Compared with growth in blood from healthy volunteers, growth of PA14 in the blood from severely burned patients significantly altered the expression of 2596 genes, with expression of 1060 genes enhanced, while that of 1536 genes was reduced. Genes whose expression was significantly reduced included genes related to quorum sensing, quorum sensing-controlled virulence factors and transport of heme, phosphate, and phosphonate. Genes whose expression was significantly enhanced were related to the type III secretion system, the pyochelin iron-acquisition system, flagellum synthesis, and pyocyanin production. We confirmed changes in expression of many of these genes using qRT-PCR. Although severe burns altered the levels of different blood components in each patient, the growth of PA14 in their blood produced similar changes in the expression of each gene. These results suggest that, in response to changes in the blood of severely burned patients and as part of its survival strategy, P. aeruginosa enhances the expression of certain virulence genes and reduces the expression of others.
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Genome-wide identification of genes necessary for biofilm formation by nosocomial pathogen Stenotrophomonas maltophilia reveals that orphan response regulator FsnR is a critical modulator. Appl Environ Microbiol 2016; 81:1200-9. [PMID: 25480754 DOI: 10.1128/aem.03408-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Stenotrophomonas maltophilia is a Gram-negative bacterial pathogen of increasing concern to human health. Most clinical isolates of S. maltophilia efficiently form biofilms on biotic and abiotic surfaces, making this bacterium resistant to a number of antibiotic treatments and therefore difficult to eliminate. To date, very few studies have investigated the molecular and regulatory mechanisms responsible for S. maltophilia biofilm formation. Here we constructed a random transposon insertion mutant library of S. maltophilia ATCC 13637 and screened 14,028 clones. A total of 46 nonredundant genes were identified. Mutants of these genes exhibited marked changes in biofilm formation, suggesting that multiple physiological pathways, including extracellular polysaccharide production, purine synthesis, transportation, and peptide and lipid synthesis, are involved in bacterial cell aggregation. Of these genes, 20 putatively contributed to flagellar biosynthesis, indicating a critical role for cell motility in S.maltophilia biofilm formation. Genetic and biochemical evidence demonstrated that an orphan response regulator, FsnR, activated transcription of at least two flagellum-associated operons by directly binding to their promoters. This regulatory protein plays a fundamental role in controlling flagellar assembly, cell motility, and biofilm formation. These results provide a genetic basis to systematically study biofilm formation of S. maltophilia.
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Control of Biofilms with the Fatty Acid Signaling Molecule cis-2-Decenoic Acid. Pharmaceuticals (Basel) 2015; 8:816-35. [PMID: 26610524 PMCID: PMC4695811 DOI: 10.3390/ph8040816] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 11/11/2015] [Accepted: 11/18/2015] [Indexed: 12/26/2022] Open
Abstract
Biofilms are complex communities of microorganisms in organized structures attached to surfaces. Importantly, biofilms are a major cause of bacterial infections in humans, and remain one of the most significant challenges to modern medical practice. Unfortunately, conventional therapies have shown to be inadequate in the treatment of most chronic biofilm infections based on the extraordinary innate tolerance of biofilms to antibiotics. Antagonists of quorum sensing signaling molecules have been used as means to control biofilms. QS and other cell-cell communication molecules are able to revert biofilm tolerance, prevent biofilm formation and disrupt fully developed biofilms, albeit with restricted effectiveness. Recently however, it has been demonstrated that Pseudomonas aeruginosa produces a small messenger molecule cis-2-decenoic acid (cis-DA) that shows significant promise as an effective adjunctive to antimicrobial treatment of biofilms. This molecule is responsible for induction of the native biofilm dispersion response in a range of Gram-negative and Gram-positive bacteria and in yeast, and has been shown to reverse persistence, increase microbial metabolic activity and significantly enhance the cidal effects of conventional antimicrobial agents. In this manuscript, the use of cis-2-decenoic acid as a novel agent for biofilm control is discussed. Stimulating the biofilm dispersion response as a novel antimicrobial strategy holds significant promise for enhanced treatment of infections and in the prevention of biofilm formation.
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Elkhatib W, Noreddin A. Efficacy of ciprofloxacin-clarithromycin combination against drug-resistant Pseudomonas aeruginosa mature biofilm using in vitro experimental model. Microb Drug Resist 2015; 20:575-82. [PMID: 25050970 DOI: 10.1089/mdr.2014.0024] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Pseudomonas aeruginosa is the main cause of mortality in cystic fibrosis patients and eradication of its biofilm represents a substantial problem clinically. In this study, biofilm of a cystic fibrosis strain P. aeruginosa PACI22 was established and confocal laser scanning microscopy was utilized for biofilm visualization. A quantitative time-kill biofilm model was implemented in vitro to assess the biocidal effect of ciprofloxacin, clarithromycin, and their combination at concentration levels ranged from 0.5× to 64× minimum biofilm inhibitory concentrations (MBIC) against the biofilm and the mean log bacterial densities (Log CFU/ml) retrieved from the biofilm were monitored by frequent sampling at 0, 3, 6, 9, 12, and 24 hr throughout the experiment. The results revealed that none of the tested antibiotics alone could completely eradicate the biofilm-ensconced bacteria at 0.5-64× MBIC values after 24 hr of treatment. Conversely, ciprofloxacin-clarithromycin combination at 32-64× MBIC entirely exterminated the biofilm. Furthermore, a substantial in vitro synergism between ciprofloxacin and clarithromycin against the biofilm was experimentally verified. This promising synergism affords scientific rationale for further in vivo investigations to evaluate the therapeutic potential of this combination for treatment of chronic pulmonary infections caused by P. aeruginosa biofilms.
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Affiliation(s)
- Walid Elkhatib
- 1 Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University , Cairo, Egypt
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Biofilm-related infections: bridging the gap between clinical management and fundamental aspects of recalcitrance toward antibiotics. Microbiol Mol Biol Rev 2015; 78:510-43. [PMID: 25184564 DOI: 10.1128/mmbr.00013-14] [Citation(s) in RCA: 837] [Impact Index Per Article: 83.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Surface-associated microbial communities, called biofilms, are present in all environments. Although biofilms play an important positive role in a variety of ecosystems, they also have many negative effects, including biofilm-related infections in medical settings. The ability of pathogenic biofilms to survive in the presence of high concentrations of antibiotics is called "recalcitrance" and is a characteristic property of the biofilm lifestyle, leading to treatment failure and infection recurrence. This review presents our current understanding of the molecular mechanisms of biofilm recalcitrance toward antibiotics and describes how recent progress has improved our capacity to design original and efficient strategies to prevent or eradicate biofilm-related infections.
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40
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Olsen I. Biofilm-specific antibiotic tolerance and resistance. Eur J Clin Microbiol Infect Dis 2015; 34:877-86. [PMID: 25630538 DOI: 10.1007/s10096-015-2323-z] [Citation(s) in RCA: 488] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 01/09/2015] [Indexed: 01/30/2023]
Abstract
Biofilms are heterogeneous structures composed of bacterial cells surrounded by a matrix and attached to solid surfaces. The bacteria here are 100 to 1,000 times more tolerant to antimicrobials than corresponding planktonic cells. Biofilms can be difficult to eradicate when they cause biofilm-related diseases, e.g., implant infections, cystic fibrosis, urinary tract infections, and periodontal diseases. A number of phenotypic features of the biofilm can be involved in biofilm-specific tolerance and resistance. Little is known about the molecular mechanisms involved. The current review deals with both phenotypic and molecular mechanisms of biofilm-specific antibiotic tolerance and resistance.
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Affiliation(s)
- I Olsen
- Department of Oral Biology, Faculty of Dentistry, University of Oslo, P.O. Box 1052 Blindern, Oslo, 0316, Norway,
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Jolivet-Gougeon A, Bonnaure-Mallet M. Biofilms as a mechanism of bacterial resistance. DRUG DISCOVERY TODAY. TECHNOLOGIES 2015; 11:49-56. [PMID: 24847653 DOI: 10.1016/j.ddtec.2014.02.003] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Inside the biofilm, antimicrobial agents must overcome high cell density, an increased number of resistant mutants, substance delivery, molecular exchanges, such as high levels of beta-lactamases or inducers of efflux pump expression, and specific adaptive cells, so-called persisters. The environment within the biofilm modulates the response to antibiotics, especially when the SOS response or DNA repair systems are involved. Exposure to subinhibitory concentrations of antibiotics can enhance biofilm formation and mutagenesis. Thus, a global response to cell stress seems to be responsible for antibiotic-induced biofilm formation.
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Taylor PK, Yeung ATY, Hancock REW. Antibiotic resistance in Pseudomonas aeruginosa biofilms: towards the development of novel anti-biofilm therapies. J Biotechnol 2014; 191:121-30. [PMID: 25240440 DOI: 10.1016/j.jbiotec.2014.09.003] [Citation(s) in RCA: 230] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/03/2014] [Accepted: 09/04/2014] [Indexed: 12/23/2022]
Abstract
The growth of bacteria as structured aggregates termed biofilms leads to their protection from harsh environmental conditions such as physical and chemical stresses, shearing forces, and limited nutrient availability. Because of this highly adapted ability to survive adverse environmental conditions, bacterial biofilms are recalcitrant to antibiotic therapies and immune clearance. This is particularly problematic in hospital settings where biofilms are a frequent cause of chronic and device-related infections and constitute a significant burden on the health-care system. The major therapeutic strategy against infections is the use of antibiotics, which, due to adaptive resistance, are often insufficient to clear biofilm infections. Thus, novel biofilm-specific therapies are required. Specific features of biofilm development, such as surface adherence, extracellular matrix formation, quorum sensing, and highly regulated biofilm maturation and dispersal are currently being studied as targets to be exploited in the development of novel biofilm-specific treatments. Using Pseudomonas aeruginosa for illustrative purposes, this review highlights the antibiotic resistance mechanisms of biofilms, and discusses current research into novel biofilm-specific therapies.
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Affiliation(s)
- Patrick K Taylor
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, 2259 Lower Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Amy T Y Yeung
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, 2259 Lower Mall, Vancouver, British Columbia V6T 1Z4, Canada
| | - Robert E W Hancock
- Centre for Microbial Diseases and Immunity Research, University of British Columbia, 2259 Lower Mall, Vancouver, British Columbia V6T 1Z4, Canada.
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Puig C, Marti S, Hermans PWM, de Jonge MI, Ardanuy C, Liñares J, Langereis JD. Incorporation of phosphorylcholine into the lipooligosaccharide of nontypeable Haemophilus influenzae does not correlate with the level of biofilm formation in vitro. Infect Immun 2014; 82:1591-9. [PMID: 24452688 PMCID: PMC3993405 DOI: 10.1128/iai.01445-13] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 01/20/2014] [Indexed: 12/20/2022] Open
Abstract
Nontypeable Haemophilus influenzae (NTHi) is an opportunistic pathogen that causes otitis media in children and community-acquired pneumonia or exacerbations of chronic obstructive pulmonary disease in adults. A large variety of studies suggest that biofilm formation by NTHi may be an important step in the pathogenesis of this bacterium. The objective of this report was to determine the relationship between the presence of phosphorylcholine in the lipooligosaccharide of NTHi and the level of biofilm formation. The study was performed on 111 NTHi clinical isolates collected from oropharyngeal samples of healthy children, middle ear fluid of children with otitis media, and sputum samples of patients with chronic obstructive pulmonary disease or community-acquired pneumonia. NTHi clinical isolates presented a large variation in the level of biofilm formation in a static assay and phosphorylcholine content. Isolates collected from the oropharynx and middle ear fluid of children tended to have more phosphorylcholine and made denser biofilms than isolates collected from sputum samples of patients with chronic obstructive pulmonary disease or community-acquired pneumonia. No correlation was observed between biofilm formation and the presence of phosphorylcholine in the lipooligosaccharide for either planktonic or biofilm growth. This lack of correlation was confirmed by abrogating phosphorylcholine incorporation into lipooligosaccharide through licA gene deletion, which had strain-specific effects on biofilm formation. Altogether, we present strong evidence to conclude that there is no correlation between biofilm formation in a static assay and the presence of phosphorylcholine in lipooligosaccharide in a large collection of clinical NTHi isolates collected from different groups of patients.
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Affiliation(s)
- Carmen Puig
- Microbiology Department, Hospital Universitari de Bellvitge-Universitat de Barcelona, IDIBELL, Barcelona, Spain
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
- CIBER de Enfermedades Respiratorias, ISCIII, Madrid, Spain
| | - Sara Marti
- Microbiology Department, Hospital Universitari de Bellvitge-Universitat de Barcelona, IDIBELL, Barcelona, Spain
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
- CIBER de Enfermedades Respiratorias, ISCIII, Madrid, Spain
| | - Peter W. M. Hermans
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Marien I. de Jonge
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Carmen Ardanuy
- Microbiology Department, Hospital Universitari de Bellvitge-Universitat de Barcelona, IDIBELL, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, ISCIII, Madrid, Spain
| | - Josefina Liñares
- Microbiology Department, Hospital Universitari de Bellvitge-Universitat de Barcelona, IDIBELL, Barcelona, Spain
- CIBER de Enfermedades Respiratorias, ISCIII, Madrid, Spain
| | - Jeroen D. Langereis
- Laboratory of Pediatric Infectious Diseases, Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
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Elkhatib W, Noreddin A. In Vitro Antibiofilm Efficacies of Different Antibiotic Combinations with Zinc Sulfate against Pseudomonas aeruginosa Recovered from Hospitalized Patients with Urinary Tract Infection. Antibiotics (Basel) 2014; 3:64-84. [PMID: 27025734 PMCID: PMC4790350 DOI: 10.3390/antibiotics3010064] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 01/31/2014] [Accepted: 02/07/2014] [Indexed: 11/16/2022] Open
Abstract
Urinary tract infections (UTIs) are a serious healthcare dilemma influencing millions of patients every year and represent the second most frequent type of body infection. Pseudomonas aeruginosa is a multidrug-resistant pathogen causing numerous chronic biofilm-associated infections including urinary tract, nosocomial, and medical devices-related infections. In the present study, the biofilm of P. aeruginosa CCIN34519, recovered from inpatients with UTIs, was established on polystyrene substratum and scanning electron microscopy (SEM) and was utilized for visualization of the biofilm. A previously described in vitro system for real-time monitoring of biofilm growth/inhibition was utilized to assess the antimicrobial effects of ciprofloxacin, levofloxacin, moxifloxacin, norfloxacin, ertapenem, ceftriaxone, gentamicin, and tobramycin as single antibiotics as well as in combinations with zinc sulfate (2.5 mM) against P.aeruginosa CCIN34519 biofilm. Meanwhile, minimum inhibitory concentrations (MICs) at 24 h and mutant prevention concentrations (MPCs) at 96 h were determined for the aforementioned antibiotics. The real-time monitoring data revealed diverse responses of P.aeruginosa CCIN34519 biofilm to the tested antibiotic-zinc sulfate combinations with potential synergisms in cases of fluoroquinolones (ciprofloxacin, levofloxacin, moxifloxacin, and norfloxacin) and carbapenem (ertapenem) as demonstrated by reduced MIC and MPC values. Conversely, considerable antagonisms were observed with cephalosporin (ceftriaxone) and aminoglycosides (gentamicin, and tobramycin) as shown by substantially increased MICs and MPCs values. Further deliberate in vivo investigations for the promising synergisms are required to evaluate their therapeutic potentials for treatment of UTIs caused by P. aeruginosa biofilms as well as for developing preventive strategies.
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Affiliation(s)
- Walid Elkhatib
- Department of Microbiology and Immunology, Faculty of Pharmacy, Ain Shams University, African Union Organization St. Abbassia, Cairo 11566, Egypt.
- Department of Pharmacy Practice, School of Pharmacy, Hampton University, Kittrell Hall Hampton, Virginia 23668, USA.
| | - Ayman Noreddin
- Department of Pharmacy Practice, School of Pharmacy, Hampton University, Kittrell Hall Hampton, Virginia 23668, USA.
- Graduate Program of Biomedical Sciences, Eastern Virginia Medical School, 825 Fairfax Ave, Norfolk, Virginia 23507, USA.
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