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Prados C, Zamarrón E, Girón R, Quintana E, Máiz L, Nieto R, Asensio Ó, Álvarez-Sala R, Quirós S, Martínez-Redondo M, Mangas A, Martínez-Martínez T. ¿Qué supuso el consenso español para el tratamiento de la infección por Pseudomonas aeruginosa en pacientes con fibrosis quística en la infección pulmonar inicial? Med Clin (Barc) 2020; 154:232-235. [DOI: 10.1016/j.medcli.2019.08.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 08/06/2019] [Accepted: 08/26/2019] [Indexed: 11/25/2022]
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Li H, Li X, Song C, Zhang Y, Wang Z, Liu Z, Wei H, Yu J. Autoinducer-2 Facilitates Pseudomonas aeruginosa PAO1 Pathogenicity in Vitro and in Vivo. Front Microbiol 2017; 8:1944. [PMID: 29089927 PMCID: PMC5651085 DOI: 10.3389/fmicb.2017.01944] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/21/2017] [Indexed: 02/01/2023] Open
Abstract
Bacterial communication systems, such as quorum sensing (QS), have provided new insights of alternative approaches in antimicrobial treatment. We recently reported that one QS signal, named as autoinducer-2 (AI-2), can affect the behaviors of Pseudomonas aeruginosa PAO1 in a dose-dependent manner. In this study, we aimed to investigate the effects of AI-2 on P. aeruginosa PAO1 biofilm formation and virulence factors production in vitro, and in vivo using a pulmonary infection mouse model. Exogenous AI-2 resulted in increased biofilms architecture, the number of viable cells, and the yield of pyocyanin and elastase virulence factors in wild type P. aeruginosa PAO1. However, no such effect was observed in P. aeruginosa lasR rhlR mutant strain. In vivo, the use of AI-2 significantly increased the mortality, lung bacterial count and histological lung damage of mice with acute P. aeruginosa PAO1 infection. Our data suggest that AI-2 promotes the formation of P. aeruginosa PAO1 biofilms and the production of virulence factors by interfering with P. aeruginosa QS systems, resulting in decreased host survival. AI-2 may be a therapeutic target for the clinical treatment of a co-infection of P. aeruginosa and AI-2 producing bacteria.
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Affiliation(s)
- Hongdong Li
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, China
| | - Xingyuan Li
- Department of Pharmacy, Chongqing Red Cross Hospital, Chongqing, China
| | - Chao Song
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, China
| | - Yunhui Zhang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, China
| | - Zhengli Wang
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, China
| | - Zhenqiu Liu
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, China
| | - Hong Wei
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, China
| | - Jialin Yu
- Department of Neonatology, Children's Hospital of Chongqing Medical University, Chongqing, China.,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China.,China International Science and Technology Cooperation Base of Child Development and Critical Disorders, Chongqing, China.,Chongqing Key Laboratory of Child Infection and Immunity, Chongqing, China.,Shenzhen University General Hospital, Shenzhen, China
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Abstract
Chronic polymicrobial infections are associated with increased virulence compared to monospecies infections. However, our understanding of microbial dynamics during polymicrobial infection is limited. A recent study by Limoli and colleagues (D. H. Limoli, G. B. Whitfield, T. Kitao, M. L. Ivey, M. R. Davis, Jr., et al., mBio 8:e00186-17, 2017, https://doi.org/10.1128/mBio.00186-17) provides insight into a mechanism that may contribute to the coexistence of Pseudomonas aeruginosa and Staphylococcus aureus in the cystic fibrosis (CF) lung. CF lung infections have frequently been used to investigate microbial interactions due to both the complex polymicrobial community and chronic nature of these infections. The hypothesis of Limoli et al. is that the conversion of P. aeruginosa to its mucoidy phenotype during chronic CF infection promotes coexistence by diminishing its ability to kill S. aureus Highlighting a new facet of microbial interaction between two species that are traditionally thought of as competitors, this study provides a platform for studying community assembly in a relevant infection setting.
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Moore JE, Mastoridis P. Clinical implications of Pseudomonas aeruginosa location in the lungs of patients with cystic fibrosis. J Clin Pharm Ther 2017; 42:259-267. [PMID: 28374433 DOI: 10.1111/jcpt.12521] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 03/05/2017] [Indexed: 12/18/2022]
Abstract
WHAT IS KNOWN AND OBJECTIVE Pseudomonas aeruginosa is the leading cause of lung infection in patients with cystic fibrosis (CF) and is associated with significant morbidity and mortality. Antibiotics are regarded as the foundational pharmacological treatment for the suppressive management of chronic P. aeruginosa infections and to eradicate the first infection by P. aeruginosa. Inhalation remains a preferred route for drug administration, providing direct access to the site of infection while minimizing systemic side effects. Effective suppressive management of P. aeruginosa infections, however, requires an understanding of the location of the bacteria in the lungs and consideration of the factors that could limit access of the inhaled antibiotic to the infected area. This review provides a systematic assessment of the scientific literature to gain insight into the location of P. aeruginosa in the lungs of patients with CF and its clinical implications. The characteristics of antibiotic inhalation systems are also discussed in this context. METHODS We reviewed evidence-based literature from both human and animal studies in which P. aeruginosa lung location was reported. Relevant publications were identified through a screening strategy and summarized by reported P. aeruginosa location. RESULTS AND DISCUSSION Most areas of the conductive and respiratory zones of the lungs are susceptible to P. aeruginosa colonization. Deposition of an inhaled antibiotic is dependent on the device and formulation characteristics, as well as the ability of the patient to generate sufficient inhaled volume. As patients with CF often experience a decline in lung function, the challenge is to ensure that the inhaled antibiotic can be delivered throughout the bronchial tree. WHAT IS NEW AND CONCLUSION An effective drug delivery system that can target P. aeruginosa in both the respiratory and conductive zones is required. The chosen inhalation device should also offer a drug formulation that can be quickly and effectively delivered to specific lung locations, with minimal inspiratory effort from the patient.
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Affiliation(s)
- J E Moore
- Northern Ireland Public Health Laboratory, Department of Bacteriology, Belfast City Hospital, Belfast, UK
| | - P Mastoridis
- Respiratory Department, Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA
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5
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Li H, Li X, Wang Z, Fu Y, Ai Q, Dong Y, Yu J. Autoinducer-2 regulates Pseudomonas aeruginosa PAO1 biofilm formation and virulence production in a dose-dependent manner. BMC Microbiol 2015; 15:192. [PMID: 26420312 PMCID: PMC4588260 DOI: 10.1186/s12866-015-0529-y] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 09/23/2015] [Indexed: 12/13/2022] Open
Abstract
Background Pseudomonas aeruginosa is an opportunistic pathogen that is the leading cause of iatrogenic infections in critically ill patients, especially those undergoing mechanical ventilation. In this study, we investigated the effects of the universal signaling molecule autoinducer-2 (AI-2) in biofilm formation of P. aeruginosa PAO1. Results The addition of 0.1 nM, 1 nM, and 10 nM exogenous AI-2 to P. aeruginosa PAO1 increased biofilm formation, bacterial viability, and the production of virulence factors. However, compared to the 10 nM AI-2 group, higher concentrations of AI-2 (100 nM and 1 μM) reduced biofilm formation, bacterial viability, and the production of virulence factors. Consistent with the changes in morphology, gene expression analysis revealed that AI-2 up-regulated the expression of quorum sensing-associated genes and genes encoding virulence factors at lower concentrations and down-regulated these genes at higher concentrations. Conclusions Our study demonstrated that exogenous AI-2 acted in a dose-dependent manner to regulate P. aeruginosa biofilm formation and virulence factors secretion via modulating the expression of quorum sensing-associated genes and may be targeted to treat P. aeruginosa biofilm infections.
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Affiliation(s)
- Hongdong Li
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China. .,Key Laboratory of Pediatrics in Chongqing and Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.
| | - Xingyuan Li
- Department of Pharmacy, Chongqing Red Cross Hospital, Chongqing, China.
| | - Zhengli Wang
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China. .,Key Laboratory of Pediatrics in Chongqing and Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.
| | - Yakun Fu
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China. .,Key Laboratory of Pediatrics in Chongqing and Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.
| | - Qing Ai
- Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China. .,Key Laboratory of Pediatrics in Chongqing and Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.
| | - Ying Dong
- Department of Paediatrics, Children's Hospital of Fudan University, Shanghai, China.
| | - Jialin Yu
- Department of Neonatology, Children's Hospital, Chongqing Medical University, Chongqing, China. .,Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing, China. .,Key Laboratory of Pediatrics in Chongqing and Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China.
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6
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Gómez-Lozano M, Marvig RL, Molina-Santiago C, Tribelli PM, Ramos JL, Molin S. Diversity of small RNAs expressed in Pseudomonas species. ENVIRONMENTAL MICROBIOLOGY REPORTS 2015; 7:227-236. [PMID: 25394275 DOI: 10.1111/1758-2229.12233] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 10/18/2014] [Accepted: 10/28/2014] [Indexed: 06/04/2023]
Abstract
RNA sequencing (RNA-seq) has revealed several hundreds of previously undetected small RNAs (sRNAs) in all bacterial species investigated, including strains of Pseudomonas aeruginosa, Pseudomonas putida and Pseudomonas syringae. Nonetheless, only little is known about the extent of conservation of expressed sRNAs across strains and species. In this study, we have used RNA-seq to identify sRNAs in P. putida DOT-T1E and Pseudomonas extremaustralis 14-3b. This is the first strain of P. extremaustralis and the second strain of P. putida to have their transcriptomes analysed for sRNAs, and we identify the presence of around 150 novel sRNAs in each strain. Furthermore, we provide a comparison based on sequence conservation of all the sRNAs detected by RNA-seq in the Pseudomonas species investigated so far. Our results show that the extent of sRNA conservation across different species is very limited. In addition, when comparing the sRNAs expressed in different strains of the same species, we observe that numerous sRNAs exhibit a strain-specific expression pattern. These results support the idea that the evolution of most bacterial sRNAs is rapid, which limits the extent of both interspecies and intraspecies conservation.
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Affiliation(s)
- María Gómez-Lozano
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, DK-2970, Denmark
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7
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Mauch RM, Levy CE. Serum antibodies to Pseudomonas aeruginosa in cystic fibrosis as a diagnostic tool: A systematic review. J Cyst Fibros 2014; 13:499-507. [DOI: 10.1016/j.jcf.2014.01.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 01/20/2014] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
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Transport of nanoparticles and tobramycin-loaded liposomes in Burkholderia cepacia complex biofilms. PLoS One 2013; 8:e79220. [PMID: 24244452 PMCID: PMC3828301 DOI: 10.1371/journal.pone.0079220] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Accepted: 09/23/2013] [Indexed: 12/17/2022] Open
Abstract
Due to the intrinsic resistance of Burkholderia cepacia complex (Bcc) to many antibiotics and the production of a broad range of virulence factors, lung infections by these bacteria, primarily occurring in cystic fibrosis (CF) patients, are very difficult to treat. In addition, the ability of Bcc organisms to form biofilms contributes to their persistence in the CF lung. As Bcc infections are associated with poor clinical outcome, there is an urgent need for new effective therapies to treat these infections. In the present study, we investigated whether liposomal tobramycin displayed an increased anti-biofilm effect against Bcc bacteria compared to free tobramycin. Single particle tracking (SPT) was used to study the transport of positively and negatively charged nanospheres in Bcc biofilms as a model for the transport of liposomes. Negatively charged nanospheres became immobilized in close proximity of biofilm cell clusters, while positively charged nanospheres interacted with fiber-like structures, probably eDNA. Based on these data, encapsulation of tobramycin in negatively charged liposomes appeared promising for targeted drug delivery. However, the anti-biofilm effect of tobramycin encapsulated into neutral or anionic liposomes did not increase compared to that of free tobramycin. Probably, the fusion of the anionic liposomes with the negatively charged bacterial surface of Bcc bacteria was limited by electrostatic repulsive forces. The lack of a substantial anti-biofilm effect of tobramycin encapsulated in neutral liposomes could be further investigated by increasing the liposomal tobramycin concentration. However, this was hampered by the low encapsulation efficiency of tobramycin in these liposomes.
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Sriramulu D. Evolution and impact of bacterial drug resistance in the context of cystic fibrosis disease and nosocomial settings. Microbiol Insights 2013; 6:29-36. [PMID: 24826072 PMCID: PMC3987750 DOI: 10.4137/mbi.s10792] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The use of antibiotics is unavoidable in trying to treat acute infections and in the prevention and control of chronic infections. Over the years, an ever increasing number of infections has escalated the use of antibiotics, which has necessitated action against an emerging bacterial resistance. There seems to be a continuous acquisition of new resistance mechanisms among bacteria that switch niches between human, animals, and the environment. An antibiotic resistant strain emerges when it acquires the DNA that confers the added capacity needed to survive in an unusual niche. Once acquired, a new resistance mechanism evolves according to the dynamics of the microenvironment; there is then a high probability that it is transferred to other species or to an avirulent strain of the same species. A well understood model for studying emerging antibiotic resistance and its impact is Pseudomonas aeruginosa, an opportunistic pathogen which is able to cause acute and chronic infections in nosocomial settings. This bacterium has a huge genetic repertoire consisting of genes that encode both innate and acquired antibiotic resistance traits. Besides acute infections, chronic colonization of P. aeruginosa in the lungs of cystic fibrosis (CF) patients plays a significant role in morbidity and mortality. Antibiotics used in the treatment of such infections has increased the longevity of patients over the last several decades. However, emerging multidrug resistant strains and the eventual increase in the dosage of antibiotic(s) is of major concern. Though there are various infections that are treated by single/combined antibiotics, the particular case of P. aeruginosa infection in CF patients serves as a reference for understanding the impact of overuse of antibiotics and emerging antibiotic resistant strains. This mini review presents the need for judicious use of antibiotics to treat various types of infections, protecting patients and the environment, as well as achieving a better treatment outcome.
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Affiliation(s)
- Dinesh Sriramulu
- Shres Consultancy, Aparna Towers, Near Lakshmi Hospital, Chittur Road, Palakkad, Kerala, India
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10
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Piccorelli AV, Schluchter MD. Jointly modeling the relationship between longitudinal and survival data subject to left truncation with applications to cystic fibrosis. Stat Med 2012; 31:3931-45. [PMID: 22786556 PMCID: PMC5551379 DOI: 10.1002/sim.5469] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2010] [Accepted: 05/10/2012] [Indexed: 11/05/2022]
Abstract
Numerous methods for joint analysis of longitudinal measures of a continuous outcome y and a time to event outcome T have recently been developed either to focus on the longitudinal data y while correcting for nonignorable dropout, to predict the survival outcome T using the longitudinal data y, or to examine the relationship between y and T. The motivating problem for our work is in joint modeling of the serial measurements of pulmonary function (FEV1% predicted) and survival in cystic fibrosis (CF) patients using registry data. Within the CF registry data, an additional complexity is that not all patients have been followed from birth; therefore, some patients have delayed entry into the study while others may have been missed completely, giving rise to a left truncated distribution. This paper shows in joint modeling situations where y and T are not independent, that it is necessary to account for this left truncation to obtain valid parameter estimates related to both survival and the longitudinal marker. We assume a linear random effects model for FEV1% predicted, where the random intercept and slope of FEV1% predicted, along with a specified transformation of the age at death follow a trivariate normal distribution. We develop an expectation-maximization algorithm for maximum likelihood estimation of parameters, which takes left truncation and right censoring of survival times into account. The methods are illustrated using simulation studies and using data from CF patients in a registry followed at Rainbow Babies and Children's Hospital, Cleveland, OH.
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Affiliation(s)
- Annalisa V Piccorelli
- Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH, USA.
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Patel VS, Sitapara RA, Gore A, Phan B, Sharma L, Sampat V, Li JH, Yang H, Chavan SS, Wang H, Tracey KJ, Mantell LL. High Mobility Group Box-1 mediates hyperoxia-induced impairment of Pseudomonas aeruginosa clearance and inflammatory lung injury in mice. Am J Respir Cell Mol Biol 2012; 48:280-7. [PMID: 23087050 DOI: 10.1165/rcmb.2012-0279oc] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Mechanical ventilation with supraphysiological concentrations of oxygen (hyperoxia) is routinely used to treat patients with respiratory distress. However, a significant number of patients on ventilators exhibit enhanced susceptibility to infections and develop ventilator-associated pneumonia (VAP). Pseudomonas aeruginosa (PA) is one of the most common species of bacteria found in these patients. Previously, we demonstrated that prolonged exposure to hyperoxia can compromise the ability of alveolar macrophages (AMs), an essential part of the innate immunity, to phagocytose PA. This study sought to investigate the potential molecular mechanisms underlying hyperoxia-compromised innate immunity against bacterial infection in a murine model of PA pneumonia. Here, we show that exposure to hyperoxia (≥ 99% O2) led to a significant elevation in concentrations of airway high mobility group box-1 (HMGB1) and increased mortality in C57BL/6 mice infected with PA. Treatment of these mice with a neutralizing anti-HMGB1 monoclonal antibody (mAb) resulted in a reduction in bacterial counts, injury, and numbers of neutrophils in the lungs, and an increase in leukocyte phagocytic activity compared with mice receiving control mAb. This improved phagocytic function was associated with reduced concentrations of airway HMGB1. The correlation between phagocytic activity and concentrations of extracellular HMGB1 was also observed in cultured macrophages. These results indicate a pathogenic role for HMGB1 in hyperoxia-induced impairment with regard to a host's ability to clear bacteria and inflammatory lung injury. Thus, HMGB1 may provide a novel molecular target for improving hyperoxia-compromised innate immunity in patients with VAP.
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Affiliation(s)
- Vivek S Patel
- Division of Cardiopulmonary Toxicology, Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John’s University, Queens, NY 11439, USA
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12
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Greally P, Whitaker P, Peckham D. Challenges with current inhaled treatments for chronic Pseudomonas aeruginosa infection in patients with cystic fibrosis. Curr Med Res Opin 2012; 28:1059-67. [PMID: 22401602 DOI: 10.1185/03007995.2012.674500] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Pseudomonas aeruginosa (Pa) is the predominant pathogen infecting the airways of patients with cystic fibrosis (CF). Initial colonization is usually transient and associated with non-mucoid strains, which can be eradicated if identified early. This strategy can prevent, or at least delay, chronic Pa infection, which eventually develops in the majority of patients by their late teens or early adulthood. This article discusses the management and latest treatment developments of Pa lung infection in patients with CF, with a focus on nebulized antibiotic therapy. METHODS PubMed was searched to identify English language articles published up until August 2011 using combinations of the following key words: 'antibiotics', 'chronic', 'cystic fibrosis', 'eradication', 'exacerbations', 'guidelines', 'inhaled', 'intravenous', 'lung infection', 'burden', 'adherence', 'patient segregation', 'pseudomonas aeruginosa' and 'resistance'. FINDINGS Antibiotics form a central part of the treatment regimens for chronic Pa lung infection. Current treatment guidelines recommend that patients with chronic pulmonary infection with Pa should receive long-term inhaled anti-pseudomonal therapy to preserve lung function, and to reduce the frequency of pulmonary exacerbations and hospital admissions. While antibiotic resistance seems to increase with frequent antibiotic use, this does not appear to impact on clinical outcome. Negative aspects of therapy include the time needed for drug administration and subsequent cleaning of the equipment. These factors cause a significant treatment burden and impact on adherence. The availability of more convenient formulations and delivery vehicles for anti-pseudomonal antibiotics may help overcome some of these challenges. CONCLUSIONS Current challenges in the management of CF patients with chronic Pa lung infection are numerous. The availability of novel anti-pseudomonal antibiotic formulations/devices is anticipated to improve treatment adherence in patients with CF, and could improve clinical outcomes. Thus, there is hope for improved survival in individuals with CF suffering from chronic pulmonary infection with Pa.
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Affiliation(s)
- Peter Greally
- National Children's Hospital, Tallaght, Dublin, Ireland.
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Entezari M, Weiss DJ, Sitapara R, Whittaker L, Wargo MJ, Li J, Wang H, Yang H, Sharma L, Phan BD, Javdan M, Chavan SS, Miller EJ, Tracey KJ, Mantell LL. Inhibition of high-mobility group box 1 protein (HMGB1) enhances bacterial clearance and protects against Pseudomonas Aeruginosa pneumonia in cystic fibrosis. Mol Med 2012; 18:477-85. [PMID: 22314397 DOI: 10.2119/molmed.2012.00024] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Accepted: 01/31/2012] [Indexed: 01/08/2023] Open
Abstract
Pulmonary infection with Pseudomonas aeruginosa and neutrophilic lung inflammation significantly contribute to morbidity and mortality in cystic fibrosis (CF). High-mobility group box 1 protein (HMGB1), a ubiquitous DNA binding protein that promotes inflammatory tissue injury, is significantly elevated in CF sputum. However, its mechanistic and potential therapeutic implications in CF were previously unknown. We found that HMGB1 levels were significantly elevated in bronchoalveolar lavage fluids (BALs) of CF patients and cystic fibrosis transmembrane conductance regulator (CFTR )(-/-) mice. Neutralizing anti-HMGB1 monoclonal antibody (mAb) conferred significant protection against P. aeruginosa-induced neutrophil recruitment, lung injury and bacterial infection in both CFTR(-/-) and wild-type mice. Alveolar macrophages isolated from mice treated with anti-HMGB1 mAb had improved phagocytic activity, which was suppressed by direct exposure to HMGB1. In addition, BAL from CF patients significantly impaired macrophage phagocytotic function, and this impairment was attenuated by HMGB1-neutralizing antibodies. The HMGB1-mediated suppression of bacterial phagocytosis was attenuated in macrophages lacking toll-like receptor (TLR)-4, suggesting a critical role for TLR4 in signaling HMGB1-mediated macrophage dysfunction. These studies demonstrate that the elevated levels of HMGB1 in CF airways are critical for neutrophil recruitment and persistent presence of P. aeruginosa in the lung. Thus, HMGB1 may provide a therapeutic target for reducing bacterial infection and lung inflammation in CF.
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Affiliation(s)
- Maria Entezari
- Cardiopulmonary Toxicology, Department of Pharmaceutical Sciences, St. John's University College of Pharmacy and Allied Health Professions, Queens, New York 11439, USA
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14
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Chaves CRMM, Cunha ALP. Avaliação e recomendações nutricionais para crianças e adolescentes com fibrose cística. REVISTA PAULISTA DE PEDIATRIA 2012. [DOI: 10.1590/s0103-05822012000100019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJETIVO: Revisar e discutir evidências sobre a avaliação do estado nutricional e as recomendações para o tratamento nutricional de crianças e adolescentes com fibrose cística. FONTES DE DADOS: Bancos de dados MEDLINE (versão PubMed) e Latin American and Caribbean Center on Health Sciences Information (LILACS), entre 1984 a 2009. Aplicou-se a combinação dos seguintes descritores: fibrose cística, estado nutricional, criança e adolescente - em inglês e português. SÍNTESE DOS DADOS: A fibrose cística é uma doença genética, de evolução crônica, progressiva e fatal. Resulta do defeito na proteína reguladora transmembrana que regula a condução de cloro e, consequentemente, o fluxo de sódio e água através da membrana apical das células epiteliais. Pacientes fibrocísticos são vulneráveis à desnutrição, que resulta do desequilíbrio entre ingestão alimentar, gasto e perdas energéticas. Novos conhecimentos sobre a fisiopatologia da doença, adquiridos nas últimas décadas, resultaram em mudanças significativas nas atuais recomendações energéticas e principalmente de lipídeos. A importância da nutrição no bem-estar e sobrevida dos fibrocísticos está bem estabelecida, assim como a associação entre a desnutrição e a deterioração da função pulmonar. Existem múltiplos fatores inter-relacionados que afetam o estado nutricional, tais como, mutação genética, insuficiência pancreática, ressecção intestinal, perda de sais e ácidos biliares, refluxo gastroesofágico, inflamação e infecções pulmonares, diabetes e condições emocionais. CONCLUSÕES: O monitoramento nutricional e o aconselhamento dietético são elementos chave no manejo de crianças e adolescentes com fibrose cística com o intuito de controlar a sintomatologia e a progressão da doença, proporcionando melhor qualidade de vida.
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Topal H, Fulcher NB, Bitterman J, Salazar E, Buck J, Levin LR, Cann MJ, Wolfgang MC, Steegborn C. Crystal structure and regulation mechanisms of the CyaB adenylyl cyclase from the human pathogen Pseudomonas aeruginosa. J Mol Biol 2011; 416:271-86. [PMID: 22226839 DOI: 10.1016/j.jmb.2011.12.045] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Revised: 12/18/2011] [Accepted: 12/21/2011] [Indexed: 12/15/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic bacterial pathogen and a major cause of healthcare-associated infections. While the organism's intrinsic and acquired resistance to most antibiotics hinders treatment of P. aeruginosa infections, the regulatory networks controlling its virulence provide novel targets for drug development. CyaB, a key regulator of P. aeruginosa virulence, belongs to the Class III adenylyl cyclase (AC) family of enzymes that synthesize the second messenger cyclic adenosine 3',5'-monophosphate. These enzymes consist of a conserved catalytic domain fused to one or more regulatory domains. We describe here the biochemical and structural characterization of CyaB and its inhibition by small molecules. We show that CyaB belongs to the Class IIIb subfamily, and like other subfamily members, its activity is stimulated by inorganic carbon. CyaB is also regulated by its N-terminal MASE2 (membrane-associated sensor 2) domain, which acts as a membrane anchor. Using a genetic screen, we identified activating mutations in CyaB. By solving the crystal structure of the CyaB catalytic domain, we rationalized the effects of these mutations and propose that CyaB employs regulatory mechanisms similar to other Class III ACs. The CyaB structure further indicates subtle differences compared to other Class III ACs in both the active site and the inhibitor binding pocket. Consistent with these differences, we observed a unique inhibition profile, including identification of a CyaB selective compound. Overall, our results reveal mechanistic details of the physiological and pharmacological regulation of CyaB and provide the basis for its exploitation as a therapeutic drug target.
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Affiliation(s)
- Hüsnü Topal
- Department of Physiological Chemistry, Ruhr-University Bochum, 44801 Bochum, Germany
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16
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The Pseudomonas aeruginosa Vfr regulator controls global virulence factor expression through cyclic AMP-dependent and -independent mechanisms. J Bacteriol 2010; 192:3553-64. [PMID: 20494996 DOI: 10.1128/jb.00363-10] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Vfr is a global regulator of virulence factor expression in the human pathogen Pseudomonas aeruginosa. Although indirect evidence suggests that Vfr activity is controlled by cyclic AMP (cAMP), it has been hypothesized that the putative cAMP binding pocket of Vfr may accommodate additional cyclic nucleotides. In this study, we used two different approaches to generate apo-Vfr and examined its ability to bind a representative set of virulence gene promoters in the absence and presence of different allosteric effectors. Of the cyclic nucleotides tested, only cAMP was able to restore DNA binding activity to apo-Vfr. In contrast, cGMP was capable of inhibiting cAMP-Vfr DNA binding. Further, we demonstrate that vfr expression is autoregulated and cAMP dependent and involves Vfr binding to a previously unidentified site within the vfr promoter region. Using a combination of in vitro and in vivo approaches, we show that cAMP is required for Vfr-dependent regulation of a specific subset of virulence genes. In contrast, we discovered that Vfr controls expression of the lasR promoter in a cAMP-independent manner. In summary, our data support a model in which Vfr controls virulence gene expression by distinct (cAMP-dependent and -independent) mechanisms, which may allow P. aeruginosa to fine-tune its virulence program in response to specific host cues or environments.
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Fulcher NB, Holliday PM, Klem E, Cann MJ, Wolfgang MC. The Pseudomonas aeruginosa Chp chemosensory system regulates intracellular cAMP levels by modulating adenylate cyclase activity. Mol Microbiol 2010; 76:889-904. [PMID: 20345659 PMCID: PMC2906755 DOI: 10.1111/j.1365-2958.2010.07135.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Multiple virulence systems in the opportunistic pathogen Pseudomonas aeruginosa are regulated by the second messenger signalling molecule adenosine 3', 5'-cyclic monophosphate (cAMP). Production of cAMP by the putative adenylate cyclase enzyme CyaB represents a critical control point for virulence gene regulation. To identify regulators of CyaB, we screened a transposon insertion library for mutants with reduced intracellular cAMP. The majority of insertions resulting in reduced cAMP mapped to the Chp gene cluster encoding a putative chemotaxis-like chemosensory system. Further genetic analysis of the Chp system revealed that it has both positive and negative effects on intracellular cAMP and that it regulates cAMP levels by modulating CyaB activity. The Chp system was previously implicated in the production and function of type IV pili (TFP). Given that cAMP and the cAMP-dependent transcriptional regulator Vfr control TFP biogenesis gene expression, we explored the relationship between cAMP, the Chp system and TFP regulation. We discovered that the Chp system controls TFP production through modulation of cAMP while control of TFP-dependent twitching motility is cAMP-independent. Overall, our data define a novel function for a chemotaxis-like system in controlling cAMP production and establish a regulatory link between the Chp system, TFP and other cAMP-dependent virulence systems.
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Affiliation(s)
- Nanette B. Fulcher
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, NC 27599
| | - Phillip M. Holliday
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Erich Klem
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, NC 27599
| | - Martin J. Cann
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, United Kingdom
| | - Matthew C. Wolfgang
- Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina, Chapel Hill, NC 27599
- Department of Microbiology and Immunology, University of North Carolina, Chapel Hill, NC 27599
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Sudfeld CR, Dasenbrook EC, Merz WG, Carroll KC, Boyle MP. Prevalence and risk factors for recovery of filamentous fungi in individuals with cystic fibrosis. J Cyst Fibros 2009; 9:110-6. [PMID: 20045384 DOI: 10.1016/j.jcf.2009.11.010] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2009] [Revised: 11/29/2009] [Accepted: 11/30/2009] [Indexed: 02/07/2023]
Abstract
BACKGROUND Filamentous fungi are frequently recovered from respiratory cultures of individuals with CF. METHODS A CF cohort database was utilized to determine filamentous fungal prevalence and risk factors. RESULTS The prevalence of filamentous fungal isolation increased from 2.0% in 1997 to 28.7% in 2007. The odds of isolating filamentous fungi during a quarter was greater in CF adults [p<0.001], during chronic oral antibiotic use [p=0.002] and increased with each 10% drop in FEV(1) percent predicted [p=0.005], while inhaled corticosteroids surprisingly decreased the likelihood [p=0.012]. The direction of these effects persisted after excluding individuals with ABPA. A sub-analysis determined older age [p=0.019] and use of inhaled antibiotics [p=0.011] were independent risk factors for onset of fungal colonization. CONCLUSIONS This study suggests that isolation of filamentous fungi in CF at JHH has increased and risk factors include older age, decreased lung function, and chronic oral antibiotics.
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Affiliation(s)
- Christopher R Sudfeld
- Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe Street, 6th Floor, Baltimore, MD 21205, United States.
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Elborn JS, Hodson M, Bertram C. Implementation of European standards of care for cystic fibrosis--control and treatment of infection. J Cyst Fibros 2009; 8:211-7. [PMID: 19372063 DOI: 10.1016/j.jcf.2009.03.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2008] [Revised: 02/20/2009] [Accepted: 03/05/2009] [Indexed: 11/16/2022]
Abstract
BACKGROUND Several guidelines on infection control and treatment of infection exist for cystic fibrosis (CF) caregivers, although the extent of implementation is variable. METHODS Adherence to European Consensus Guidelines for CF was studied by sending surveys to named healthcare professionals in 487 European CF centres/units. Qualitative data analysis was performed. RESULTS A total of 177/547 (32%) surveys were returned. Infection control policies were implemented by most (77%) respondents. Separation of patients with Burkholderia cepacia was more common in adults (95%) than children (9%), and was implemented by 53% of respondents for Pseudomonas aeruginosa. Nebulised colistin plus oral ciprofloxacin was the most common (43%) therapy for P. aeruginosa infection. First infections of P. aeruginosa were usually treated with inhaled tobramycin; 41% of repondents did not intervene until lung function deteriorated. Most exacerbations were treated for less than the recommended period. CONCLUSIONS European Consensus Guidelines are widely adhered to. Areas for improvement include: initiating therapy for exacerbations early, separating infected patients and optimising duration of antibiotic therapy.
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Affiliation(s)
- J S Elborn
- Respiratory Medicine Research Group, Queen's University, Belfast City Hospital, Ground Floor, Lisburn Rd, Belfast, BT9 7AB, UK.
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20
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Netotea S, Bertani I, Steindler L, Kerényi A, Venturi V, Pongor S. A simple model for the early events of quorum sensing in Pseudomonas aeruginosa: modeling bacterial swarming as the movement of an "activation zone". Biol Direct 2009; 4:6. [PMID: 19216743 PMCID: PMC2660287 DOI: 10.1186/1745-6150-4-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2008] [Accepted: 02/12/2009] [Indexed: 02/05/2023] Open
Abstract
Background Quorum sensing (QS) is a form of gene regulation based on cell-density that depends on inter-cellular communication. While there are a variety of models for bacterial colony morphology, there is little work linking QS genes to movement in an open system. Results The onset of swarming in environmental P. aeruginosa PUPa3 was described with a simplified computational model in which cells in random motion communicate via a diffusible signal (representing N-acyl homoserine lactones, AHL) as well as diffusible, secreted factors (enzymes, biosurfactans, i.e. "public goods") that regulate the intensity of movement and metabolism in a threshold-dependent manner. As a result, an "activation zone" emerges in which nutrients and other public goods are present in sufficient quantities, and swarming is the spontaneous displacement of this high cell-density zone towards nutrients and/or exogenous signals. The model correctly predicts the behaviour of genomic knockout mutants in which the QS genes responsible either for the synthesis (lasI, rhlI) or the sensing (lasR, rhlR) of AHL signals were inactivated. For wild type cells the model predicts sustained colony growth that can however be collapsed by the overconsumption of nutrients. Conclusion While in more complex models include self-orienting abilities that allow cells to follow concentration gradients of nutrients and chemotactic agents, in this model, displacement towards nutrients or environmental signals is an emergent property of the community that results from the action of a few, well-defined QS genes and their products. Still the model qualitatively describes the salient properties of QS bacteria, i.e. the density-dependent onset of swarming as well as the response to exogenous signals or cues. Reviewers This paper was reviewed by Gáspár Jékely, L. Aravind, Eugene V. Koonin and Artem Novozhilov (nominated by Eugene V. Koonin).
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Affiliation(s)
- Sergiu Netotea
- Biological Research Center of the Hungarian Academy of Sciences, Szeged, Hungary.
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21
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Molecular identification of bacteria in bronchoalveolar lavage fluid from children with cystic fibrosis. Proc Natl Acad Sci U S A 2007; 104:20529-33. [PMID: 18077362 DOI: 10.1073/pnas.0709804104] [Citation(s) in RCA: 282] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Culture of bronchoalveolar lavage fluid (BALF) is the gold standard for detection of pathogens in the lower airways in cystic fibrosis (CF). However, current culture results do not explain all clinical observations in CF, including negative culture results during pulmonary exacerbation and inflammation in the absence of pathogens. We hypothesize that organisms not routinely identified by culture occur in the CF airway and may contribute to disease. To test this hypothesis we used a culture-independent molecular approach, based on use of rRNA sequence analysis, to assess the bacterial composition of BALF from children with CF and disease controls (DC). Specimens from 42 subjects (28 CF) were examined, and approximately 6,600 total clones were screened to identify 121 species of bacteria. In general, a single rRNA type dominated clone libraries from CF specimens, but not DC. Thirteen CF subjects contained bacteria that are not routinely assessed by culture. In four CF subjects, candidate pathogens were identified and include the anaerobe Prevotella denticola, a Lysobacter sp., and members of the Rickettsiales. The presumptive pathogens Tropheryma whipplei and Granulicatella elegans were identified in cases from the DC group. The presence of unexpected bacteria in CF may explain inflammation without documented pathogens and consequent failure to respond to standard treatment. These results show that molecular techniques provide a broader perspective on airway bacteria than do routine clinical cultures and thus can identify targets for further clinical evaluation.
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22
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Nishimaki K, Nawata J, Okada S, Hattori T, Ohno I. Neutrophil survival-enhancing activity in sputum from patients with diffuse panbronchiolitis. Respir Med 2005; 99:910-7. [PMID: 15939254 DOI: 10.1016/j.rmed.2004.12.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Diffuse panbronchiolitis (DPB) is a life-threatening airway disease in which neutrophils persistently and massively emigrating to the airways cause progressive and irreversible tissue damage. However, the pathogenesis of the airway inflammation remains unclear. The failure of non-inflammatory removal of emigrating neutrophils due to delayed apoptosis has been proposed as a mechanism by which the neutrophilic inflammation persists. Therefore, we aimed to investigate whether an activity that delays neutrophil apoptosis is present at the inflamed sites in DPB. Neutrophils isolated from normal volunteers were cultured with sputum extracts of patients with DPB, and viability and apoptosis of neutrophil was evaluated for the culture period. Neutrophils cultured with sputum extracts for 2 and 3 days showed significantly enhanced survival compared to those with medium alone. The neutrophil survival-enhancing activity in sputum extracts was heat-labile and partially, but significantly, neutralized with anti-human GM-CSF, but not with anti-human G-CSF antibody. The enhancement of neutrophil survival was associated with an inhibition of apoptosis demonstrated by cytology, TUNEL assay and DNA fragmentation analysis. These results suggest that neutrophil apoptosis is prevented by survival-enhancing factors including GM-CSF in the airways of DPB, leading to neutrophil death by necrosis that causes further recruitment and activation of neutrophils.
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Affiliation(s)
- Katsushi Nishimaki
- Department of Respiratory and Infectious Diseases, Tohoku University Graduate School of Medicine, 1-1 Seiryo-machi, Sendai 980-8574, Japan
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23
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Loos BG, John RP, Laine ML. Identification of genetic risk factors for periodontitis and possible mechanisms of action. J Clin Periodontol 2005; 32 Suppl 6:159-79. [PMID: 16128836 DOI: 10.1111/j.1600-051x.2005.00806.x] [Citation(s) in RCA: 208] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIM To review the literature for genetic risk factors associated with periodontitis. METHODS Computerized search of the literature in English using key words: Periodontitis; Genes; Mutation; Polymorphism; Risk. RESULTS AND CONCLUSIONS Mutations in the cathepsin C gene (CTSC) have been identified as causal for the Papillon-Lefèvre syndrome (PLS), which includes prepubertal periodontitis (PP). Some CTSC mutations are causal for PP without PLS. No relationship has been demonstrated between CTSC mutations and other forms of periodontitis. Genetic polymorphisms in a candidate gene approach have been explored as risk factors for periodontitis. There is limited evidence that some polymorphisms in the genes encoding interleukins (IL)-1, Fc gamma receptors (Fc gammaR), IL-10 and the vitamin D receptor, may be associated with periodontitis in certain ethnic groups. However relatively large variations in carriage rates of the Rare (R)-alleles among studies on any polymorphism were observed. The available studies appear under-powered and do not adequately take into account other pertinent risk factors for periodontitis. Future studies should include larger cohorts, should clearly define phenotypes and should adequately control for other risk factors. In addition to the candidate gene approach, alternative strategies need to be considered to elucidate the gene variations, which confer risk for periodontitis.
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Affiliation(s)
- Bruno G Loos
- Department of Periodontology, Acadcemic Center for Dentistry Amsterdam (ACTA), University of Amsterdam, The Netherlands.
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24
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Brockhurst MA, Buckling A, Rainey PB. The effect of a bacteriophage on diversification of the opportunistic bacterial pathogen, Pseudomonas aeruginosa. Proc Biol Sci 2005; 272:1385-91. [PMID: 16006335 PMCID: PMC1560335 DOI: 10.1098/rspb.2005.3086] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic human pathogen that colonizes the lungs of cystic fibrosis (CF) patients. CF lungs often contain a diverse range of P. aeruginosa phenotypes, some of which are likely to contribute to the persistence of infection, yet the causes of diversity are unclear. While the ecological heterogeneity of the lung environment and therapeutic regimes are probable factors, a role for parasitic bacteriophage cannot be ruled out. Parasites have been implicated as a key ecological variable driving the evolution of diversity in host populations. PP7 drove cycles of morphological diversification in host populations of P. aeruginosa due to the de novo evolution of small-rough colony variants that coexisted with large diffuse colony morph bacteria. In the absence of phage, bacteria only displayed the large diffuse colony morphology of the wild-type. Further assays revealed there to be two distinct types of resistant bacteria; these had very different ecological phenotypes, yet each carried a cost of resistance.
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Affiliation(s)
- Michael A Brockhurst
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
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25
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Abstract
Gene therapy holds promise for the treatment of a range of inherited diseases, such as cystic fibrosis. However, efficient delivery and expression of the therapeutic transgene at levels sufficient to result in phenotypic correction of cystic fibrosis pulmonary disease has proved elusive. There are many reasons for this lack of progress, both macroscopically in terms of airway defence mechanisms and at the molecular level with regard to effective cDNA delivery. This review of approaches to cystic fibrosis gene therapy covers these areas in detail and highlights recent progress in the field. For gene therapy to be effective in patients with cystic fibrosis, the cDNA encoding the cystic fibrosis transmembrane conductance regulator protein must be delivered effectively to the nucleus of the epithelial cells lining the bronchial tree within the lungs. Expression of the transgene must be maintained at adequate levels for the lifetime of the patient, either by repeat dosage of the vector or by targeting airway stem cells. Clinical trials of gene therapy for cystic fibrosis have demonstrated proof of principle, but gene expression has been limited to 30 days at best. Results suggest that viral vectors such as adenovirus and adeno-associated virus are unsuited to repeat dosing, as the immune response reduces the effectiveness of each subsequent dose. Nonviral approaches, such as cationic liposomes, appear more suited to repeat dosing, but have been less effective. Current work regarding non-viral gene delivery is now focused on understanding the mechanisms involved in cell entry, endosomal escape and nuclear import of the transgene. There is now increasing evidence to suggest that additional ligands that facilitate endosomal escape or contain a nuclear localization signal may enhance liposome-mediated gene delivery. Much progress in this area has been informed by advances in our understanding of the mechanisms by which viruses deliver their genomes to the nuclei of host cells.
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Affiliation(s)
- Tim W R Lee
- School of Biochemistry and Microbiology, University of Leeds, Leeds LS2 9JT, UK.
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26
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Raia V, Maiuri L, Ciacci C, Ricciardelli I, Vacca L, Auricchio S, Cimmino M, Cavaliere M, Nardone M, Cesaro A, Malcolm J, Quaratino S, Londei M. Inhibition of p38 mitogen activated protein kinase controls airway inflammation in cystic fibrosis. Thorax 2005; 60:773-80. [PMID: 15994249 PMCID: PMC1747526 DOI: 10.1136/thx.2005.042564] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Cystic fibrosis (CF) airways are characterised by chronic inflammation, increased interleukin (IL)-8 secretion, and neutrophil activation which are considered the principal factors of morbidity and mortality in CF patients. Optimising management of this chronic inflammatory response is therefore a key issue of basic and clinical CF research. Several reports have addressed ways to manage CF airways inflammation, and an attractive therapeutic strategy may be the inhibition of the p38-mitogen activated protein kinase (p38-MAP-k) pathway. METHODS A new ex vivo model was used to study the mucosal inflammatory response to environmental airways stimuli. Nasal biopsy tissues from CF patients and controls were cultured ex vivo for 20 minutes, 4 hours, and 24 hours in the presence of lipopolysaccharide (LPS) from Pseudomonas aeruginosa (PA) with and without the p38-MAP-k inhibitor SB203580. Quantitative mRNA assessment, immunohistochemistry, and Western blots were used to detect the expression and modulation of inflammatory markers. RESULTS PA-LPS challenge induced a time dependent mucosal inflammation indicated by rapid epithelial activation, IL-8 release, COX-2 upregulation, and neutrophil migration to the upper mucosal layers. Some of these LPS induced changes (IL-8 release and neutrophil migration) were specific to CF tissues. SB203580 significantly controlled all LPS induced mucosal changes in CF tissues. CONCLUSION These findings provide a rationale and proof of principle for the potential use of p38-MAP-k inhibitors to control inflammation in patients with CF.
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Affiliation(s)
- V Raia
- Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK
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van Schaik EJ, Giltner CL, Audette GF, Keizer DW, Bautista DL, Slupsky CM, Sykes BD, Irvin RT. DNA binding: a novel function of Pseudomonas aeruginosa type IV pili. J Bacteriol 2005; 187:1455-64. [PMID: 15687210 PMCID: PMC545619 DOI: 10.1128/jb.187.4.1455-1464.2005] [Citation(s) in RCA: 105] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa produces multifunctional, polar, filamentous appendages termed type IV pili. Type IV pili are involved in colonization during infection, twitching motility, biofilm formation, bacteriophage infection, and natural transformation. Electrostatic surface analysis of modeled pilus fibers generated from P. aeruginosa strain PAK, K122-4, and KB-7 pilin monomers suggested that a solvent-exposed band of positive charge may be a common feature of all type IV pili. Several functions of type IV pili, including natural transformation and biofilm formation, involve DNA. We investigated the ability of P. aeruginosa type IV pili to bind DNA. Purified PAK, K122-4, and KB-7 pili were observed to bind both bacterial plasmid and salmon sperm DNA in a concentration-dependent and saturable manner. PAK pili had the highest affinity for DNA, followed by K122-4 and KB-7 pili. DNA binding involved backbone interactions and preferential binding to pyrimidine residues even though there was no evidence of sequence-specific binding. Pilus-mediated DNA binding was a function of the intact pilus and thus required elements present in the quaternary structure. However, binding also involved the pilus tip as tip-specific, but not base-specific, antibodies inhibited DNA binding. The conservation of a Thr residue in all type IV pilin monomers examined to date, along with the electrostatic data, implies that DNA binding is a conserved function of type IV pili. Pilus-mediated DNA binding could be important for biofilm formation both in vivo during an infection and ex vivo on abiotic surfaces.
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Affiliation(s)
- Erin J van Schaik
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada
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28
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Chughtai B, O'Riordan TG. Potential role of inhibitors of neutrophil elastase in treating diseases of the airway. ACTA ACUST UNITED AC 2005; 17:289-98. [PMID: 15684729 DOI: 10.1089/jam.2004.17.289] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The potential therapeutic use of inhibitors of neutrophil elastase (NE) is reviewed with emphasis on diseases of the airway. In addition to its proteolytic properties, NE is a potent secretagogue and may be pro-inflammatory. The properties of natural occurring inhibitors of NE such as alpha-one antitrypsin and secretory leukoprotease inhibitor are reviewed. In addition, recombinant versions of naturally occurring inhibitors and synthetic small molecule inhibitors are potential therapies for respiratory diseases. For recombinant proteins, aerosol administration has been the preferred method of delivery. The inhaled mode of delivery can complicate the determination of dose responsiveness and thus the evaluation of safety and efficacy of these agents. In addition to the aerosolization issue, there remain other significant barriers to the successful deployment of these agents in clinical trials. These include the need for high standards for purification of recombinant proteins, the lack of understanding of interaction with airway secretions, the controversy over role of NE in the pathogenesis of nonhereditary COPD, and asthma, while the need for the safety of new classes of systemically delivered small molecules will need to be established.
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Affiliation(s)
- Bilal Chughtai
- Division of Pulmonary/Critical Care Medicine, Stony Brook University, Stony Brook, New York 11984-8172, USA
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29
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Abstract
Using a flow cell biofilm model, we showed that a sub-MIC of azithromycin (AZM) can delay but not inhibit Pseudomonas aeruginosa biofilm formation and results in the development of a stable AZM resistance phenotype. Furthermore, mature biofilms were not affected by AZM.
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Affiliation(s)
- Richard J Gillis
- Department of Microbiology and Immunology, Box 672, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA
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30
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MENDELIAN GENETIC TRAITS. Mol Med 2005. [DOI: 10.1016/b978-012699057-7/50003-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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31
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Arnold H, Bumann D, Felies M, Gewecke B, Sörensen M, Gessner JE, Freihorst J, von Specht BU, Baumann U. Enhanced immunogenicity in the murine airway mucosa with an attenuated Salmonella live vaccine expressing OprF-OprI from Pseudomonas aeruginosa. Infect Immun 2004; 72:6546-53. [PMID: 15501786 PMCID: PMC523058 DOI: 10.1128/iai.72.11.6546-6553.2004] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We constructed an oral live vaccine based on the attenuated aroA mutant Salmonella enterica serovar Typhimurium strain SL3261 expressing outer membrane proteins F and I (OprF-OprI) from Pseudomonas aeruginosa and investigated it in a mouse model. Strains with in vivo inducible protein expression with the PpacC promoter showed good infection rates and immunogenicity but failed to engender detectable antibodies in the lung. However, a systemic booster vaccination following an oral primary immunization yielded high immunoglobulin A (IgA) and IgG antibody levels in both upper and lower airways superior to conventional systemic or mucosal booster vaccination alone. In addition, the proportion of IgG1 and IgG2a antibodies suggested that the systemic booster does not alter the more TH1-like type of response induced by the oral Salmonella primary vaccination. We conclude that an oral primary systemic booster vaccination strategy with an appropriate mucosal vector may be advantageous in diseases with the risk of P. aeruginosa airway infection, such as cystic fibrosis.
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Affiliation(s)
- Heinz Arnold
- Department of Pediatric Pulmonology and Neonatology, Hannover Medical School, 30623, Germany
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32
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Blondelle SE, Pinilla C, Boggiano C. Synthetic combinatorial libraries as an alternative strategy for the development of novel treatments for infectious diseases. Methods Enzymol 2004; 369:322-44. [PMID: 14722962 DOI: 10.1016/s0076-6879(03)69018-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
Affiliation(s)
- Sylvie E Blondelle
- Torrey Pines Institute for Molecular Studies, 3550 General Atomics Court, San Diego, California 92121, USA
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Phillips RM, Six DA, Dennis EA, Ghosh P. In vivo phospholipase activity of the Pseudomonas aeruginosa cytotoxin ExoU and protection of mammalian cells with phospholipase A2 inhibitors. J Biol Chem 2003; 278:41326-32. [PMID: 12915403 DOI: 10.1074/jbc.m302472200] [Citation(s) in RCA: 143] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
A number of clinical isolates of Pseudomonas aeruginosa are cytotoxic to mammalian cells due to the action of the 74-kDa protein ExoU, which is secreted into host cells by the type III secretion system and whose function is unknown. Here we report that the swift and profound cytotoxicity induced by purified ExoU or by an ExoU-expressing strain of P. aeruginosa is blocked by various inhibitors of cytosolic (cPLA2) and Ca2+ -independent (iPLA2) phospholipase A2 enzymes. In contrast, no cytoprotection is offered by inhibitors of secreted phospholipase A2 enzymes or by a number of inhibitors of signal transduction pathways. This suggests that phospholipase A2 inhibitors may represent a novel mode of treatment for acute P. aeruginosa infections. We find that 300-600 molecules of ExoU/cell are required to achieve half-maximal cell killing and that ExoU localizes to the host cell plasma membrane in punctate fashion. We also show that ExoU interacts in vitro with an inhibitor of cPLA2 and iPLA2 enzymes and contains a putative serine-aspartate catalytic dyad homologous to those found in cPLA2 and iPLA2 enzymes. Mutation of either the serine or the aspartate renders ExoU non-cytotoxic. Although no phospholipase or esterase activity is detected in vitro, significant phospholipase activity is detected in vivo, suggesting that ExoU requires one or more host cell factors for activation as a membrane-lytic and cytotoxic phospholipase.
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Affiliation(s)
- Rebecca M Phillips
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, California 92093-0314, USA
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Göcke K, Baumann U, Hagemann H, Gabelsberger J, Hahn H, Freihorst J, von Specht BU. Mucosal vaccination with a recombinant OprF-I vaccine of Pseudomonas aeruginosa in healthy volunteers: comparison of a systemic vs. a mucosal booster schedule. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2003; 37:167-71. [PMID: 12832121 DOI: 10.1016/s0928-8244(03)00094-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
We compared the immunogenicity of two vaccination schedules with either a systemic or a mucosal booster, both following a mucosal primary vaccination with a recombinant outer membrane fusion protein of Pseudomonas aeruginosa (OprF-I) in 12 healthy volunteers. The systemic booster induced higher levels of OprF-I-specific serum antibodies of IgG isotype, with a mean+/-S.E.M. of 32.6+/-7.8x10(7) enzyme-linked immunosorbent assay (ELISA) units (EU) as compared to the nasal booster with 14.6+/-2.1x10(7) EU (P=0.05). Specific serum IgA antibodies and antibodies in saliva did not differ between the two vaccination groups. We conclude that a combined mucosal/systemic vaccination with the OprF-I vaccine may offer an enhanced systemic immunogenicity. Further studies on the long-term immunogenicity and induction of antibodies on the respiratory airway surface are warranted.
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Affiliation(s)
- Kerstin Göcke
- Paediatric Pulmonology and Neonatology, Hanover Medical School, 30623, Hanover, Germany
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Kagan VE, Borisenko GG, Serinkan BF, Tyurina YY, Tyurin VA, Jiang J, Liu SX, Shvedova AA, Fabisiak JP, Uthaisang W, Fadeel B. Appetizing rancidity of apoptotic cells for macrophages: oxidation, externalization, and recognition of phosphatidylserine. Am J Physiol Lung Cell Mol Physiol 2003; 285:L1-17. [PMID: 12788785 DOI: 10.1152/ajplung.00365.2002] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Programmed cell death (apoptosis) functions as a mechanism to eliminate unwanted or irreparably damaged cells ultimately leading to their orderly phagocytosis in the absence of calamitous inflammatory responses. Recent studies have demonstrated that the generation of free radical intermediates and subsequent oxidative stress are implicated as part of the apoptotic execution process. Oxidative stress may simply be an unavoidable yet trivial byproduct of the apoptotic machinery; alternatively, intermediates or products of oxidative stress may act as essential signals for the execution of the apoptotic program. This review is focused on the specific role of oxidative stress in apoptotic signaling, which is realized via phosphatidylserine-dependent pathways leading to recognition of apoptotic cells and their effective clearance. In particular, the mechanisms involved in selective phosphatidylserine oxidation in the plasma membrane during apoptosis and its association with disturbances of phospholipid asymmetry leading to phosphatidylserine externalization and recognition by macrophage receptors are at the center of our discussion. The putative importance of this oxidative phosphatidylserine signaling in lung physiology and disease are also discussed.
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Affiliation(s)
- V E Kagan
- Department of Environmental and Occupational Health, University of Pittsburgh, Pittsburgh, PA 15260, USA.
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Brenckmann C, Papaioannou A, Freitag A, Hennessey R, Hansen S, Ioannidis G, Webber C, Adachi J. Osteoporosis in Canadian adult cystic fibrosis patients: a descriptive study. BMC Musculoskelet Disord 2003; 4:13. [PMID: 12823863 PMCID: PMC198278 DOI: 10.1186/1471-2474-4-13] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2003] [Accepted: 06/24/2003] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Cystic fibrosis is the most common fatal autosomal recessive genetic disease in the Caucasian population. Osteoporosis is increasingly being recognised as an important complication in people with cystic fibrosis. METHODS A descriptive study of adult cystic fibrosis patients receiving care at a Canadian tertiary care hospital was conducted to evaluate the prevalence of osteoporosis, the prevalence of non-vertebral fractures, and the change in bone mineral density during the course of a year. Data on bone mineral density were obtained for 40 adult cystic fibrosis patients by reviewing dual x-ray absorptiometry scans taken at baseline (when annual scans became standard clinical practice) and one year prior to baseline. Data on prevalent fractures were obtained by reviewing all available patient charts. Clinical and laboratory data were collected from an existing clinic database. RESULTS Over half of the 40 patients had reduced T- and Z-scores at baseline. For the 27 patients who had data available one year prior to baseline, total hip and lumbar spine bone mineral density had decreased by 3.04% and 0.86% after one year while total body bone mineral density had not changed significantly. Four prior non-vertebral fractures were reported in three patients (1,146 patient-years). CONCLUSION This study confirms that osteoporosis is a significant problem in adult cystic fibrosis patients, and constitutes the first published evidence of cystic fibrosis bone disease in Canadians.
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Affiliation(s)
- Christine Brenckmann
- Department of Community Health and Epidemiology, Dalhousie University, Halifax, (B3H 4H7), Canada
| | | | - Andreas Freitag
- Adult Cystic Fibrosis Clinic, Hamilton Health Sciences – McMaster University Medical Centre, Hamilton, (L8N 3Z5), Canada
| | - Rosamund Hennessey
- Cystic Fibrosis Clinic, Hamilton Health Sciences – McMaster University Medical Centre, Hamilton, (L8N 3Z5), Canada
| | - Suzanne Hansen
- Hamilton Health Sciences – McMaster University Medical Centre, Hamilton, (L8N 3Z5), Canada
| | | | - Colin Webber
- Department of Nuclear Medicine, Hamilton Health Sciences, Hamilton, (L8N 3Z5), Canada
| | - Jonathan Adachi
- Department of Medicine, St. Joseph's Hospital, McMaster University, Hamilton, (L8N 4A6), Canada
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