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Oliver A. Clinical relevance of Pseudomonas aeruginosa hypermutation in cystic fibrosis chronic respiratory infection. J Cyst Fibros 2015; 14:e1-2. [DOI: 10.1016/j.jcf.2014.12.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Accepted: 12/05/2014] [Indexed: 11/15/2022]
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López-Causapé C, Rojo-Molinero E, Macià MD, Oliver A. The problems of antibiotic resistance in cystic fibrosis and solutions. Expert Rev Respir Med 2014; 9:73-88. [PMID: 25541089 DOI: 10.1586/17476348.2015.995640] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Chronic respiratory infection is the main cause of morbidity and mortality in cystic fibrosis (CF) patients. One of the hallmarks of these infections, led by the opportunistic pathogen Pseudomonas aeruginosa, is their long-term (lifelong) persistence despite intensive antimicrobial therapy. Antimicrobial resistance in CF is indeed a multifactorial problem, which includes physiological changes, represented by the transition from the planktonic to the biofilm mode of growth and the acquisition of multiple (antibiotic resistance) adaptive mutations catalyzed by frequent mutator phenotypes. Emerging multidrug-resistant CF pathogens, transmissible epidemic strains and transferable genetic elements (such as those encoding class B carbapenemases) also significantly contribute to this concerning scenario. Strategies directed to combat biofilm growth, prevent the emergence of mutational resistance, promote the development of novel antimicrobial agents against multidrug-resistant strains and implement strict infection control measures are thus needed.
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Affiliation(s)
- Carla López-Causapé
- Servicio de Microbiología and Unidad de Investigación, Hospital Universitario Son Espases, Instituto de Investigación Sanitaria de Palma (IdISPa), Ctra. Valldemossa 79, 07010 Palma de Mallorca, Spain
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Auerbach A, Kerem E, Assous MV, Picard E, Bar-Meir M. Is infection with hypermutable Pseudomonas aeruginosa clinically significant? J Cyst Fibros 2014; 14:347-52. [PMID: 25308183 DOI: 10.1016/j.jcf.2014.09.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 09/15/2014] [Accepted: 09/17/2014] [Indexed: 10/24/2022]
Abstract
BACKGROUND Hypermutable Pseudomonas aeruginosa (HPA) with high mutation rate due to defects in the DNA mismatch repair genes are frequently isolated in the sputum of cystic fibrosis (CF) patients. These isolates tend to be multidrug resistant and may be better adapted to the CF lung environment. However, the clinical significance of this infection has not been determined. METHODS This prospective study enrolled patients with PA infection attending CF clinics in Jerusalem between 2010 and 2011. Mutation frequency of pseudomonas isolates was determined by quantification of colonies resistant to rifampicin. RESULTS Of the 73 patients enrolled, 22 (30%) were infected with HPA. Average mutation frequency was 2.95×10(-4) in HPA and 1×10(-7) in non-HPA. Pulmonary function tests, number of pulmonary exacerbations and the response to antibiotic therapy were similar between patients infected with HPA and non-HPA isolates. The only predictors for infection with HPA were resistance to multiple antimicrobial categories (OR=4.8, 95% CI: 1.8-12.4) and previous use of inhaled colistin (OR=8.1, 95% CI: 2-30). Resistant mutant subpopulation analysis was a poor screening test for identifying HPA isolates. CONCLUSIONS Infection with hypermutable strains represents the marked ability of PA to adapt to the lung environment, but was not associated with worse clinical outcome.
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Affiliation(s)
- Adi Auerbach
- Pediatric Department, Shaare-Zedek Medical Center, Jerusalem, Israel
| | - Eitan Kerem
- Pediatric Department, Cystic Fibrosis Center, Hadassah Hebrew University Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University Hadassah Medical School, Jerusalem, Israel
| | | | - Elie Picard
- Pediatric Department, Shaare-Zedek Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University Hadassah Medical School, Jerusalem, Israel
| | - Maskit Bar-Meir
- Pediatric Department, Shaare-Zedek Medical Center, Jerusalem, Israel; Faculty of Medicine, Hebrew University Hadassah Medical School, Jerusalem, Israel.
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Oliver A, Mena A. Bacterial hypermutation in cystic fibrosis, not only for antibiotic resistance. Clin Microbiol Infect 2011; 16:798-808. [PMID: 20880409 DOI: 10.1111/j.1469-0691.2010.03250.x] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hypermutable or mutator microorganisms are those that have an increased spontaneous mutation rate as a result of defects in DNA repair or error avoidance systems. Over the last two decades, several studies have provided strong evidence for a relevant role of mutators in the evolution of natural bacterial populations, particularly in the field of infectious diseases. Among them, chronic respiratory infection with Pseudomonas aeruginosa in cystic fibrosis (CF) patients was the first natural environment to reveal the high prevalence and important role of mutators. A remarkable positive selection of mutators during the course of the chronic infection has been reported, mainly as a result of the emergence of DNA mismatch repair system (mutS, mutL or mutU)-deficient mutants, although strains defective in the GO system (mutM, mutY and mutT) have also been observed. High frequencies of mutators have also been noted among other pathogens in the CF setting, particularly Staphylococcus aureus and Haemophilus influenzae. Enhanced antimicrobial resistance development is the most thoroughly studied consequence of mutators in CF and other chronic infections, although recent studies show that mutators may additionally have important effects on the evolution of virulence, genetic adaptation to the airways of CF patients, persistence of colonization, transmissibility, and perhaps lung function decline. Further prospective clinical studies are nevertheless still needed for an in-depth evaluation of the impact of mutators on disease progression and outcome.
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Affiliation(s)
- A Oliver
- Servicio de Microbiología and Unidad de Investigación, Hospital Son Dureta, Instituto Universitario de Investigación en Ciencias de la Salud, Palma de Mallorca, Spain.
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Jolivet-Gougeon A, Kovacs B, Le Gall-David S, Le Bars H, Bousarghin L, Bonnaure-Mallet M, Lobel B, Guillé F, Soussy CJ, Tenke P. Bacterial hypermutation: clinical implications. J Med Microbiol 2011; 60:563-573. [PMID: 21349992 DOI: 10.1099/jmm.0.024083-0] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Heritable hypermutation in bacteria is mainly due to alterations in the methyl-directed mismatch repair (MMR) system. MMR-deficient strains have been described from several bacterial species, and all of the strains exhibit increased mutation frequency and recombination, which are important mechanisms for acquired drug resistance in bacteria. Antibiotics select for drug-resistant strains and refine resistance determinants on plasmids, thus stimulating DNA recombination via the MMR system. Antibiotics can also act as indirect promoters of antibiotic resistance by inducing the SOS system and certain error-prone DNA polymerases. These alterations have clinical consequences in that efficacious treatment of bacterial infections requires high doses of antibiotics and/or a combination of different classes of antimicrobial agents. There are currently few new drugs with low endogenous resistance potential, and the development of such drugs merits further research.
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Affiliation(s)
- Anne Jolivet-Gougeon
- Equipe Microbiologie, UPRES-EA 1254, Pontchaillou Teaching Hospital and Faculté des Sciences Pharmaceutiques et Biologiques, Université de Rennes I, Université Européenne de Bretagne, 2 avenue du Professeur Léon Bernard, 35043 Rennes, France
| | - Bela Kovacs
- Department of Urology, Jahn Ferenc Del-Pesti Hospital, Koves ut 2, 1204 Budapest, Hungary
| | - Sandrine Le Gall-David
- Equipe Microbiologie, UPRES-EA 1254, Pontchaillou Teaching Hospital and Faculté des Sciences Pharmaceutiques et Biologiques, Université de Rennes I, Université Européenne de Bretagne, 2 avenue du Professeur Léon Bernard, 35043 Rennes, France
| | - Hervé Le Bars
- Equipe Microbiologie, UPRES-EA 1254, Pontchaillou Teaching Hospital and Faculté des Sciences Pharmaceutiques et Biologiques, Université de Rennes I, Université Européenne de Bretagne, 2 avenue du Professeur Léon Bernard, 35043 Rennes, France
| | - Latifa Bousarghin
- Equipe Microbiologie, UPRES-EA 1254, Pontchaillou Teaching Hospital and Faculté des Sciences Pharmaceutiques et Biologiques, Université de Rennes I, Université Européenne de Bretagne, 2 avenue du Professeur Léon Bernard, 35043 Rennes, France
| | - Martine Bonnaure-Mallet
- Equipe Microbiologie, UPRES-EA 1254, Pontchaillou Teaching Hospital and Faculté des Sciences Pharmaceutiques et Biologiques, Université de Rennes I, Université Européenne de Bretagne, 2 avenue du Professeur Léon Bernard, 35043 Rennes, France
| | - Bernard Lobel
- Service d'Urologie, CHU Pontchaillou, 2 rue Henri Le Guilloux, 35033 Rennes cedex 9, France
| | - François Guillé
- Service d'Urologie, CHU Pontchaillou, 2 rue Henri Le Guilloux, 35033 Rennes cedex 9, France
| | - Claude-James Soussy
- Service de Bactériologie-Virologie-Hygiène, CHU Henri-Mondor, 51 avenue du Maréchal-de-Lattre-de-Tassigny, 94010 Créteil cedex, France
| | - Peter Tenke
- Department of Urology, Jahn Ferenc Del-Pesti Hospital, Koves ut 2, 1204 Budapest, Hungary
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Routsias JG, Karagounis P, Parvulesku G, Legakis NJ, Tsakris A. In vitro bactericidal activity of human beta-defensin 2 against nosocomial strains. Peptides 2010; 31:1654-60. [PMID: 20600430 DOI: 10.1016/j.peptides.2010.06.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 06/14/2010] [Accepted: 06/14/2010] [Indexed: 12/24/2022]
Abstract
Human beta-defensin 2 (hBD-2) is a 41-amino acid cationic peptide of the innate immune system that serves as antimicrobial molecule. We determined the bactericidal activity of synthetic hBD-2 against nosocomial strains belonging to eight different bacterial species and exhibiting various antimicrobial resistance phenotypes. The native disulfide connectivity was found essential for the bactericidal activity of hBD-2, while sodium chloride concentration was reversely associated with its potency. hBD-2 exhibited high bactericidal activity against Acinetobacter baumannii, Pseudomonas aeruginosa, Enterococcus faecalis, Enterococcus faecium and Staphylococcus aureus clinical strains. Characteristically, A. baumannii strains that exhibited multi-drug resistant (MDR) phenotypes were susceptible to lower concentrations of hBD-2 (vLD(90)=3.25-4.5 microg/ml) in comparison with non-MDR (wild-type) A. baumannii strains (vLD(90)=3.90-9.35 microg/ml). Bactericidal activity of hBD-2 was less pronounced against Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis strains but was significantly enhanced against strains of these species that exhibited resistance to several beta-lactam antibiotics. These observations give indications that the natural hBD-2 has a potential therapeutic role against bacterial pathogens and particularly against those exhibiting MDR phenotypes.
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Affiliation(s)
- John G Routsias
- Department of Microbiology, School of Medicine, National and Kapodistrian University of Athens, 75 M.Asias St., 11527 Athens, Greece.
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Fothergill JL, Mowat E, Ledson MJ, Walshaw MJ, Winstanley C. Fluctuations in phenotypes and genotypes within populations of Pseudomonas aeruginosa in the cystic fibrosis lung during pulmonary exacerbations. J Med Microbiol 2009; 59:472-481. [PMID: 20019149 DOI: 10.1099/jmm.0.015875-0] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Chronic respiratory infection by Pseudomonas aeruginosa contributes significantly to the morbidity and mortality associated with cystic fibrosis (CF). Using a series of phenotypic and genotypic tests on collections of 40 isolates per sputum sample, we analysed fluctuations within sputum populations of the P. aeruginosa Liverpool epidemic strain (LES) during pulmonary exacerbations. For each of three patients, three sequential sputum samples were analysed: (1) on presentation with exacerbation at the Regional Adult Cystic Fibrosis Unit, Liverpool; (2) a few days into intravenous antibiotic treatment; (3) when the patient had recovered. Fluctuations were observed in morphotype distribution, the production of virulence-associated quorum-sensing-dependent exoproducts (the phenazine compound pyocyanin and the elastase LasA), antibiotic susceptibility profiles and levels of auxotrophy. PCR assays were used to screen isolates for the presence of novel regions of the LES genome (islands and prophages) and to detect free phages. In one patient there was an increase in the prevalence of the LESGI-5 genomic island during the sampling period from 10 to 97.5 % carriage. LES phages 2-4 were detected in either the majority or all sputum samples tested, indicating widespread phage activity during the sampling period. The results of this study are indicative that significant fluctuations occur within P. aeruginosa populations during short periods of pulmonary exacerbation and intravenous antibiotic therapy.
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Affiliation(s)
- Joanne L Fothergill
- Division of Medical Microbiology, School of Infectionand Host Defence, University of Liverpool, Liverpool L69 3GA, UK.,Biomedical Research Centre, Royal Liverpool UniversityHospital, Liverpool L69 3GA, UK
| | - Eilidh Mowat
- Division of Medical Microbiology, School of Infectionand Host Defence, University of Liverpool, Liverpool L69 3GA, UK
| | - Martin J Ledson
- Regional Adult Cystic Fibrosis Unit, Liverpool Heartand Chest Hospital, Liverpool L14 3PE, UK
| | - Martin J Walshaw
- Regional Adult Cystic Fibrosis Unit, Liverpool Heartand Chest Hospital, Liverpool L14 3PE, UK
| | - Craig Winstanley
- Division of Medical Microbiology, School of Infectionand Host Defence, University of Liverpool, Liverpool L69 3GA, UK.,Biomedical Research Centre, Royal Liverpool UniversityHospital, Liverpool L69 3GA, UK
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