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Beca FA, Sengillo JD, Robles-Holmes HK, Iyer PG, Miller D, Yannuzzi NA, Flynn HW. Endophthalmitis caused by Burkholderia cepacia complex (BCC): clinical characteristics, antibiotic susceptibilities, and treatment outcomes. J Ophthalmic Inflamm Infect 2023; 13:48. [PMID: 37922028 PMCID: PMC10624773 DOI: 10.1186/s12348-023-00370-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Accepted: 10/15/2023] [Indexed: 11/05/2023] Open
Abstract
PURPOSE To report the clinical characteristics, antibiotic susceptibilities, and review the literature of Burkholderia cepacia complex (BCC) associated endophthalmitis. STUDY DESIGN Retrospective, observational case series. METHODS Clinical and microbiology records were reviewed for patients evaluated at the Bascom Palmer Eye Institute and diagnosed wisth culture-confirmed endophthalmitis due to BCC. Antibiotic susceptibility profiles were generated using standard microbiologic protocols via an automated VITEK system. RESULTS Endophthalmitis associated with BCC was diagnosed in three patients. Infection occurred in the setting of post-penetrating keratoplasty (PKP), glaucoma filtering surgery, and suspected trauma. All isolates demonstrated in vitro susceptibility to ceftazidime and meropenem. Presenting visual acuity (VA) ranged from hand motion to light perception. Initial treatment strategies included intravitreal ceftazidime (2.25 mg/0.1 mL) and vancomycin (1.0 mg/0.1 mL) injections with fortified topical antibiotics in 2 patients, and surgical debridement of a corneoscleral melt with patch graft along with both topical fortified antibiotics oral antibiotics in the third patient. In all 3 patients, there was no VA improvement at last follow-up, as 2 eyes ultimately underwent enucleation and 1 eye exhibited phthisis bulbi at last follow-up. BCC related endophthalmitis was reviewed among 13 reports. Treatment outcomes were generally poor and antibiotic resistance was common. These BCC isolates cases demonstrated broad resistance patterns, with susceptibilities to ceftazidime (58%), ciprofloxacin (53%), and gentamicin (33%). CONCLUSIONS Endophthalmitis caused by B. cepacia is a rare clinical entity with generally poor visual outcomes despite prompt treatment with appropriate antibiotics.
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Affiliation(s)
- Flavius A Beca
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Jesse D Sengillo
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Hailey K Robles-Holmes
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Prashanth G Iyer
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Darlene Miller
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Nicolas A Yannuzzi
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Harry W Flynn
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA.
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Beca FA, Sengillo JD, Robles-Holmes HK, Iyer PG, Miller D, Yannuzzi NA, Flynn HW. Endophthalmitis caused by Burkholderia cepacia complex (BCC): Clinical characteristics, antibiotic susceptibilities, and treatment outcomes. RESEARCH SQUARE 2023:rs.3.rs-3181158. [PMID: 37503162 PMCID: PMC10371171 DOI: 10.21203/rs.3.rs-3181158/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Purpose To report the clinical characteristics, antibiotic susceptibilities, and review the literature of Burkholderia cepacia complex (BCC) associated endophthalmitis. Study design Retrospective, observational case series. Methods Clinical and microbiology records were reviewed for patients evaluated at the Bascom Palmer Eye Institute and diagnosed with culture-confirmed endophthalmitis due to BCC. Antibiotic susceptibility profiles were generated using standard microbiologic protocols via an automated VITEK system. Results Endophthalmitis associated with BCC was diagnosed in three patients. Infection occurred in the setting of post-penetrating keratoplasty (PKP), glaucoma filtering surgery, and suspected trauma. All isolates demonstrated in vitro susceptibility to ceftazidime and meropenem. Presenting visual acuity (VA) ranged from hand motion to light perception. Initial treatment strategies included intravitreal ceftazidime (2.25 mg/0.1 mL) and vancomycin (1.0 mg/0.1mL) injections with fortified topical antibiotics in 2 patients, and surgical debridement of a corneoscleral melt with patch graft along with both topical fortified antibiotics oral antibiotics in the third patient. In all 3 patients, there was no VA improvement at last follow-up, as 2 eyes ultimately underwent enucleation and 1 eye exhibited phthisis bulbi at last follow-up. BCC related endophthalmitis was reviewed among 13 reports. Treatment outcomes were generally poor and antibiotic resistance was common. These BCC isolates cases demonstrated broad resistance patterns, with susceptibilities to ceftazidime (58%), ciprofloxacin (53%), and gentamicin (33%). Conclusions Endophthalmitis caused by B. cepacia is a rare clinical entity with generally poor visual outcomes despite prompt treatment with appropriate antibiotics.
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Syed I, Wooten RM. Interactions Between Pathogenic Burkholderia and the Complement System: A Review of Potential Immune Evasion Mechanisms. Front Cell Infect Microbiol 2021; 11:701362. [PMID: 34660335 PMCID: PMC8515183 DOI: 10.3389/fcimb.2021.701362] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022] Open
Abstract
The genus Burkholderia contains over 80 different Gram-negative species including both plant and human pathogens, the latter of which can be classified into one of two groups: the Burkholderia pseudomallei complex (Bpc) or the Burkholderia cepacia complex (Bcc). Bpc pathogens Burkholderia pseudomallei and Burkholderia mallei are highly virulent, and both have considerable potential for use as Tier 1 bioterrorism agents; thus there is great interest in the development of novel vaccines and therapeutics for the prevention and treatment of these infections. While Bcc pathogens Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia cepacia are not considered bioterror threats, the incredible impact these infections have on the cystic fibrosis community inspires a similar demand for vaccines and therapeutics for the prevention and treatment of these infections as well. Understanding how these pathogens interact with and evade the host immune system will help uncover novel therapeutic targets within these organisms. Given the important role of the complement system in the clearance of bacterial pathogens, this arm of the immune response must be efficiently evaded for successful infection to occur. In this review, we will introduce the Burkholderia species to be discussed, followed by a summary of the complement system and known mechanisms by which pathogens interact with this critical system to evade clearance within the host. We will conclude with a review of literature relating to the interactions between the herein discussed Burkholderia species and the host complement system, with the goal of highlighting areas in this field that warrant further investigation.
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Affiliation(s)
- Irum Syed
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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Lind C, Olsen K, Angelsen NK, Krefting EA, Fossen K, Gravningen K, Depoorter E, Vandamme P, Bertelsen G. Clinical course, treatment and visual outcome of an outbreak of Burkholderia contaminans endophthalmitis following cataract surgery. J Ophthalmic Inflamm Infect 2021; 11:12. [PMID: 33870459 PMCID: PMC8053629 DOI: 10.1186/s12348-021-00242-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/09/2021] [Indexed: 02/06/2023] Open
Abstract
Background Postoperative endophthalmitis is a rare but dreaded complication of intraocular surgery and often results in severe visual impairment or blindness. The present study describes the clinical course, treatment and visual outcome of an outbreak of Burkholderia contaminans endophthalmitis following cataract surgery. Methods Among 290 patients who underwent uneventful phacoemulsification cataract surgery at one outpatient clinic between January 4th and 28th 2019, 6 cases developed Burkholderia contaminans endophthalmitis. Clinical data were collected by retrospective review of patient records. Microbiological samples from vitreous aspirates, intraocular lenses (IOL) and lens capsules were cultured, and recA and draft whole genome sequences analysed. Results The recA sequences of all Burkholderia contaminans isolates and the allelic profile of the isolates were identical. All cases had a similar clinical presentation with rapid development of endophthalmitis symptoms with variable time to onset. The mean time to admission was 34 days (12–112 days). All cases had a seemingly favourable response to intravitreal antibiotics. However, acute recurrences occurred after long time periods (12–71 days). The cases experienced between 0 and 3 recurrences. Due to persistent infection, the cases received between 5 and 15 treatments (mean 7.8) including IOL and lens capsule explantation in 5 of 6 cases. Burkholderia contaminans was detected in all explanted lens capsules. The final corrected distance visual acuity (CDVA, Snellen chart) was between 0.8 and 1.2 and all cases had final CDVA ≥0.8. Conclusions A persistent and intensive treatment approach including total lens capsule and IOL explantation is recommended for Burkholderia contaminans endophthalmitis following cataract surgery and may lead to a favourable visual result.
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Affiliation(s)
- Caroline Lind
- Department of Ophthalmology, University Hospital of North Norway, Tromsø, Norway
| | - Karina Olsen
- Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway
| | - Nina K Angelsen
- Department of Ophthalmology, University Hospital of North Norway, Tromsø, Norway
| | - Einar A Krefting
- Department of Ophthalmology, University Hospital of North Norway, Tromsø, Norway
| | - Kristian Fossen
- Department of Ophthalmology, University Hospital of North Norway, Tromsø, Norway
| | - Kirsten Gravningen
- Department of Microbiology and Infection Control, University Hospital of North Norway, Tromsø, Norway.,Department of Infection Prevention and Preparedness, Norwegian Institute of Public Health, Oslo, Norway
| | - Eliza Depoorter
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Peter Vandamme
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Geir Bertelsen
- Department of Ophthalmology, University Hospital of North Norway, Tromsø, Norway. .,Department of Community Medicine, UiT - The Arctic University of Norway, Tromsø, Norway.
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5
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Syed I, Wooten RM. Interactions Between Pathogenic Burkholderia and the Complement System: A Review of Potential Immune Evasion Mechanisms. Front Cell Infect Microbiol 2021. [PMID: 34660335 DOI: 10.1086/69216810.3389/fcimb.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/07/2023] Open
Abstract
The genus Burkholderia contains over 80 different Gram-negative species including both plant and human pathogens, the latter of which can be classified into one of two groups: the Burkholderia pseudomallei complex (Bpc) or the Burkholderia cepacia complex (Bcc). Bpc pathogens Burkholderia pseudomallei and Burkholderia mallei are highly virulent, and both have considerable potential for use as Tier 1 bioterrorism agents; thus there is great interest in the development of novel vaccines and therapeutics for the prevention and treatment of these infections. While Bcc pathogens Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia cepacia are not considered bioterror threats, the incredible impact these infections have on the cystic fibrosis community inspires a similar demand for vaccines and therapeutics for the prevention and treatment of these infections as well. Understanding how these pathogens interact with and evade the host immune system will help uncover novel therapeutic targets within these organisms. Given the important role of the complement system in the clearance of bacterial pathogens, this arm of the immune response must be efficiently evaded for successful infection to occur. In this review, we will introduce the Burkholderia species to be discussed, followed by a summary of the complement system and known mechanisms by which pathogens interact with this critical system to evade clearance within the host. We will conclude with a review of literature relating to the interactions between the herein discussed Burkholderia species and the host complement system, with the goal of highlighting areas in this field that warrant further investigation.
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Affiliation(s)
- Irum Syed
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - R Mark Wooten
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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Ernst J, Klinger-Strobel M, Arnold K, Thamm J, Hartung A, Pletz MW, Makarewicz O, Fischer D. Polyester-based particles to overcome the obstacles of mucus and biofilms in the lung for tobramycin application under static and dynamic fluidic conditions. Eur J Pharm Biopharm 2018; 131:120-129. [PMID: 30063969 DOI: 10.1016/j.ejpb.2018.07.025] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/25/2018] [Indexed: 02/07/2023]
Abstract
Pulmonary infections with Pseudomonas aeruginosa and Burkholderia cepacia complex (Bcc) are difficult to treat and related with high mortality in some diseases like cystic fibrosis due to the recurrent formation of biofilms. The biofilm formation hinders efficient treatment with inhaled antibiotics due to a low penetration of the antibiotics through the polyanionic biofilm matrix and increased antimicrobial resistance of the biofilm-embedded bacteria. In this study, tobramycin (Tb) was encapsulated in particles based on poly(d,l,-lactide-co-glycolide) (PLGA) and poly(ethylene glycol)-co-poly(d,l,-lactide-co-glycolide) diblock (PEG-PLGA) to overcome the biofilm barrier with particle sizes of 225-231 nm (nanoparticles) and 896-902 nm (microparticles), spherical shape and negative zeta potentials. The effectiveness against biofilms of P. aeruginosa and B. cepacia was strongly enhanced by the encapsulation under fluidic experimental condition as well as under static conditions in artificial mucus. The biofilm-embedded bacteria were killed by less than 0.77 mg/l encapsulated Tb, whereas 1,000 mg/l of free Tb or the bulk mixtures of Tb and the particles were ineffective against the biofilms. Moreover, encapsulated Tb was even effective against biofilms of the intrinsically aminoglycoside-resistant B. cepacia, indicating a supportive effect of PEG and PLGA on Tb. No cytotoxicity was detected in vitro in human lung epithelial cells with any formulation.
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Affiliation(s)
- Julia Ernst
- Pharmaceutical Technology and Biopharmacy, Institute for Pharmacy, Friedrich Schiller University Jena, Jena, Germany
| | - Mareike Klinger-Strobel
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany
| | - Kathrin Arnold
- Pharmaceutical Technology and Biopharmacy, Institute for Pharmacy, Friedrich Schiller University Jena, Jena, Germany
| | - Jana Thamm
- Pharmaceutical Technology and Biopharmacy, Institute for Pharmacy, Friedrich Schiller University Jena, Jena, Germany
| | - Anita Hartung
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany
| | - Mathias W Pletz
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany
| | - Oliwia Makarewicz
- Institute for Infectious Diseases and Infection Control, Jena University Hospital, Jena, Germany.
| | - Dagmar Fischer
- Pharmaceutical Technology and Biopharmacy, Institute for Pharmacy, Friedrich Schiller University Jena, Jena, Germany; Jena Center for Soft Matter (JCSM), Friedrich Schiller University Jena, Jena, Germany
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Abstract
Antimicrobial peptides (AMPs), also known as host defense peptides, are small naturally occurring microbicidal molecules produced by the host innate immune response that function as a first line of defense to kill pathogenic microorganisms by inducing deleterious cell membrane damage. AMPs also possess signaling and chemoattractant activities and can modulate the innate immune response to enhance protective immunity or suppress inflammation. Human pathogens have evolved defense molecules and strategies to counter and survive the AMPs released by host immune cells such as neutrophils and macrophages. Here, we review the various mechanisms used by human bacterial pathogens to resist AMP-mediated killing, including surface charge modification, active efflux, alteration of membrane fluidity, inactivation by proteolytic digestion, and entrapment by surface proteins and polysaccharides. Enhanced understanding of AMP resistance at the molecular level may offer insight into the mechanisms of bacterial pathogenesis and augment the discovery of novel therapeutic targets and drug design for the treatment of recalcitrant multidrug-resistant bacterial infections.
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Pewzner-Jung Y, Tavakoli Tabazavareh S, Grassmé H, Becker KA, Japtok L, Steinmann J, Joseph T, Lang S, Tuemmler B, Schuchman EH, Lentsch AB, Kleuser B, Edwards MJ, Futerman AH, Gulbins E. Sphingoid long chain bases prevent lung infection by Pseudomonas aeruginosa. EMBO Mol Med 2015; 6:1205-14. [PMID: 25085879 PMCID: PMC4197866 DOI: 10.15252/emmm.201404075] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Cystic fibrosis patients and patients with chronic obstructive pulmonary disease, trauma, burn wound, or patients requiring ventilation are susceptible to severe pulmonary infection by Pseudomonas aeruginosa. Physiological innate defense mechanisms against this pathogen, and their alterations in lung diseases, are for the most part unknown. We now demonstrate a role for the sphingoid long chain base, sphingosine, in determining susceptibility to lung infection by P. aeruginosa. Tracheal and bronchial sphingosine levels were significantly reduced in tissues from cystic fibrosis patients and from cystic fibrosis mouse models due to reduced activity of acid ceramidase, which generates sphingosine from ceramide. Inhalation of mice with sphingosine, with a sphingosine analog, FTY720, or with acid ceramidase rescued susceptible mice from infection. Our data suggest that luminal sphingosine in tracheal and bronchial epithelial cells prevents pulmonary P. aeruginosa infection in normal individuals, paving the way for novel therapeutic paradigms based on inhalation of acid ceramidase or of sphingoid long chain bases in lung infection.
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Affiliation(s)
- Yael Pewzner-Jung
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | | | - Heike Grassmé
- Department of Molecular Biology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Katrin Anne Becker
- Department of Molecular Biology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Lukasz Japtok
- Department of Nutritional Science, University of Potsdam, Potsdam, Germany
| | - Jörg Steinmann
- Department of Microbiology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Tammar Joseph
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Stephan Lang
- Department of Otorhinolaryngology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Burkhard Tuemmler
- Klinische Forschergruppe, OE 6710, Medizinische Hochschule Hannover, Hannover, Germany
| | - Edward H Schuchman
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Alex B Lentsch
- Department of Surgery, University of Cincinnati, Cincinnati, OH, USA
| | - Burkhard Kleuser
- Department of Nutritional Science, University of Potsdam, Potsdam, Germany
| | - Michael J Edwards
- Department of Surgery, University of Cincinnati, Cincinnati, OH, USA
| | - Anthony H Futerman
- Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel
| | - Erich Gulbins
- Department of Molecular Biology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany Department of Surgery, University of Cincinnati, Cincinnati, OH, USA
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Burkholderia cepacia complex Phage-Antibiotic Synergy (PAS): antibiotics stimulate lytic phage activity. Appl Environ Microbiol 2014; 81:1132-8. [PMID: 25452284 DOI: 10.1128/aem.02850-14] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The Burkholderia cepacia complex (Bcc) is a group of at least 18 species of Gram-negative opportunistic pathogens that can cause chronic lung infection in cystic fibrosis (CF) patients. Bcc organisms possess high levels of innate antimicrobial resistance, and alternative therapeutic strategies are urgently needed. One proposed alternative treatment is phage therapy, the therapeutic application of bacterial viruses (or bacteriophages). Recently, some phages have been observed to form larger plaques in the presence of sublethal concentrations of certain antibiotics; this effect has been termed phage-antibiotic synergy (PAS). Those reports suggest that some antibiotics stimulate increased production of phages under certain conditions. The aim of this study is to examine PAS in phages that infect Burkholderia cenocepacia strains C6433 and K56-2. Bcc phages KS12 and KS14 were tested for PAS, using 6 antibiotics representing 4 different drug classes. Of the antibiotics tested, the most pronounced effects were observed for meropenem, ciprofloxacin, and tetracycline. When grown with subinhibitory concentrations of these three antibiotics, cells developed a chain-like arrangement, an elongated morphology, and a clustered arrangement, respectively. When treated with progressively higher antibiotic concentrations, both the sizes of plaques and phage titers increased, up to a maximum. B. cenocepacia K56-2-infected Galleria mellonella larvae treated with phage KS12 and low-dose meropenem demonstrated increased survival over controls treated with KS12 or antibiotic alone. These results suggest that antibiotics can be combined with phages to stimulate increased phage production and/or activity and thus improve the efficacy of bacterial killing.
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Fosmidomycin decreases membrane hopanoids and potentiates the effects of colistin on Burkholderia multivorans clinical isolates. Antimicrob Agents Chemother 2014; 58:5211-9. [PMID: 24957830 DOI: 10.1128/aac.02705-14] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cepacia complex (Bcc) pulmonary infections in people living with cystic fibrosis (CF) are difficult to treat because of the extreme intrinsic resistance of most isolates to a broad range of antimicrobials. Fosmidomycin is an antibacterial and antiparasitic agent that disrupts the isoprenoid biosynthesis pathway, a precursor to hopanoid biosynthesis. Hopanoids are involved in membrane stability and contribute to polymyxin resistance in Bcc bacteria. Checkerboard MIC assays determined that although isolates of the Bcc species B. multivorans were highly resistant to treatment with fosmidomycin or colistin (polymyxin E), antimicrobial synergy was observed in certain isolates when the antimicrobials were used in combination. Treatment with fosmidomycin decreased the MIC of colistin for isolates as much as 64-fold to as low as 8 μg/ml, a concentration achievable with colistin inhalation therapy. A liquid chromatography-tandem mass spectrometry technique was developed for the accurate quantitative determination of underivatized hopanoids in total lipid extracts, and bacteriohopanetetrol cyclitol ether (BHT-CE) was found to be the dominant hopanoid made by B. multivorans. The amount of BHT-CE made was significantly reduced upon fosmidomycin treatment of the bacteria. Uptake assays with 1-N-phenylnaphthylamine were used to determine that dual treatment with fosmidomycin and colistin increases membrane permeability, while binding assays with boron-dipyrromethene-conjugated polymyxin B illustrated that the addition of fosmidomycin had no impact on polymyxin binding. This work indicates that pharmacological suppression of membrane hopanoids with fosmidomycin treatment can increase the susceptibility of certain clinical B. multivorans isolates to colistin, an agent currently in use to treat pulmonary infections in CF patients.
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Guilhelmelli F, Vilela N, Albuquerque P, Derengowski LDS, Silva-Pereira I, Kyaw CM. Antibiotic development challenges: the various mechanisms of action of antimicrobial peptides and of bacterial resistance. Front Microbiol 2013; 4:353. [PMID: 24367355 PMCID: PMC3856679 DOI: 10.3389/fmicb.2013.00353] [Citation(s) in RCA: 334] [Impact Index Per Article: 30.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 11/06/2013] [Indexed: 12/15/2022] Open
Abstract
Antimicrobial peptides (AMPs) are natural antibiotics produced by various organisms such as mammals, arthropods, plants, and bacteria. In addition to antimicrobial activity, AMPs can induce chemokine production, accelerate angiogenesis, and wound healing and modulate apoptosis in multicellular organisms. Originally, their antimicrobial mechanism of action was thought to consist solely of an increase in pathogen cell membrane permeability, but it has already been shown that several AMPs do not modulate membrane permeability in the minimal lethal concentration. Instead, they exert their effects by inhibiting processes such as protein and cell wall synthesis, as well as enzyme activity, among others. Although resistance to these molecules is uncommon several pathogens developed different strategies to overcome AMPs killing such as surface modification, expression of efflux pumps, and secretion of proteases among others. This review describes the various mechanisms of action of AMPs and how pathogens evolve resistance to them.
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Affiliation(s)
- Fernanda Guilhelmelli
- Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília Brasília, Brazil
| | - Nathália Vilela
- Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília Brasília, Brazil
| | - Patrícia Albuquerque
- Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília Brasília, Brazil
| | - Lorena da S Derengowski
- Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília Brasília, Brazil
| | - Ildinete Silva-Pereira
- Laboratório de Biologia Molecular, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília Brasília, Brazil
| | - Cynthia M Kyaw
- Laboratório de Microbiologia, Departamento de Biologia Celular, Instituto de Ciências Biológicas, Universidade de Brasília Brasília, Brazil
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Abstract
Synthesis of Escherichia coli LpxL, which transfers a secondary laurate chain to the 2' position of lipid A, in Yersinia pestis produced bisphosphoryl hexa-acylated lipid A at 37°C, leading to significant attenuation of virulence. Our previous observations also indicated that strain χ10015(pCD1Ap) (ΔlpxP32::P(lpxL) lpxL) stimulated a strong inflammatory reaction but sickened mice before recovery and retained virulence via intranasal (i.n.) infection. The development of live, attenuated Y. pestis vaccines may be facilitated by detoxification of its lipopolysaccharide (LPS). Heterologous expression of the lipid A 1-phosphatase, LpxE, from Francisella tularensis in Y. pestis yields predominantly 1-dephosphorylated lipid A, as confirmed by mass spectrometry. Results indicated that expression of LpxE on top of LpxL provided no significant reduction in virulence of Y. pestis in mice when it was administered i.n. but actually reduced the 50% lethal dose (LD(50)) by 3 orders of magnitude when the strain was administered subcutaneously (s.c.). Additionally, LpxE synthesis in wild-type Y. pestis KIM6+(pCD1Ap) led to slight attenuation by s.c. inoculation but no virulence change by i.n. inoculation in mice. In contrast to Salmonella enterica, expression of LpxE does not attenuate the virulence of Y. pestis.
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Gnanadhas DP, Marathe SA, Chakravortty D. Biocides--resistance, cross-resistance mechanisms and assessment. Expert Opin Investig Drugs 2012; 22:191-206. [PMID: 23215733 DOI: 10.1517/13543784.2013.748035] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
IMPORTANCE OF THE FIELD Antibiotic resistance in bacterial pathogens has increased worldwide leading to treatment failures. Concerns have been raised about the use of biocides as a contributing factor to the risk of antimicrobial resistance (AMR) development. In vitro studies demonstrating increase in resistance have often been cited as evidence for increased risks. It is therefore important to understand the mechanisms of resistance employed by bacteria toward biocides used in consumer products and their potential to impart cross-resistance to therapeutic antibiotics. AREAS COVERED In this review, the mechanisms of resistance and cross-resistance reported in the literature toward biocides commonly used in consumer products are summarized. The physiological and molecular techniques used in describing and examining these mechanisms are reviewed and application of these techniques for systematic assessment of biocides for their potential to develop resistance and/or cross-resistance is discussed. EXPERT OPINION The guidelines in the usage of biocides in household or industrial purpose should be monitored and regulated to avoid the emergence of any MDR strains. The genetic and molecular methods to monitor the resistance development to biocides should be developed and included in preclinical and clinical studies.
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Affiliation(s)
- Divya Prakash Gnanadhas
- Department of Microbiology and Cell Biology, Centre for Infectious Disease Research and Biosafety Laboratories, Indian Institute of Science, Bangalore 560012, India
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El-Halfawy OM, Valvano MA. Heteroresistance of opportunistic bacteria to antimicrobial peptides: a new challenge to antimicrobial therapy of cystic fibrosis infections. ACTA ACUST UNITED AC 2011. [DOI: 10.2217/thy.11.69] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Identification of hopanoid biosynthesis genes involved in polymyxin resistance in Burkholderia multivorans. Antimicrob Agents Chemother 2011; 56:464-71. [PMID: 22006009 DOI: 10.1128/aac.00602-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A major challenge to clinical therapy of Burkholderia cepacia complex (Bcc) pulmonary infections is their innate resistance to a broad range of antimicrobials, including polycationic agents such as aminoglycosides, polymyxins, and cationic peptides. To identify genetic loci associated with this phenotype, a transposon mutant library was constructed in B. multivorans ATCC 17616 and screened for increased susceptibility to polymyxin B. Compared to the parent strain, mutant 26D7 exhibited 8- and 16-fold increases in susceptibility to polymyxin B and colistin, respectively. Genetic analysis of mutant 26D7 indicated that the transposon inserted into open reading frame (ORF) Bmul_2133, part of a putative hopanoid biosynthesis gene cluster. A strain with a mutation in another ORF in this cluster, Bmul_2134, was constructed and named RMI19. Mutant RMI19 also had increased polymyxin susceptibility. Hopanoids are analogues of eukaryotic sterols involved in membrane stability and barrier function. Strains with mutations in Bmul_2133 and Bmul_2134 showed increased permeability to 1-N-phenylnaphthylamine in the presence of increasing concentrations of polymyxin, suggesting that the putative hopanoid biosynthesis genes are involved in stabilizing outer membrane permeability, contributing to polymyxin resistance. Results from a dansyl-polymyxin binding assay demonstrated that polymyxin B does not bind well to the parent or mutant strains, suggesting that Bmul_2133 and Bmul_2134 contribute to polymyxin B resistance by a mechanism that is independent of lipopolysaccharide (LPS) binding. Through this work, we propose a role for hopanoid biosynthesis as part of the multiple antimicrobial resistance phenotype in Bcc bacteria.
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Loutet SA, Di Lorenzo F, Clarke C, Molinaro A, Valvano MA. Transcriptional responses of Burkholderia cenocepacia to polymyxin B in isogenic strains with diverse polymyxin B resistance phenotypes. BMC Genomics 2011; 12:472. [PMID: 21955326 PMCID: PMC3190405 DOI: 10.1186/1471-2164-12-472] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 09/29/2011] [Indexed: 12/04/2022] Open
Abstract
Background Burkholderia cenocepacia is a Gram-negative opportunistic pathogen displaying high resistance to antimicrobial peptides and polymyxins. We identified mechanisms of resistance by analyzing transcriptional changes to polymyxin B treatment in three isogenic B. cenocepacia strains with diverse polymyxin B resistance phenotypes: the polymyxin B-resistant parental strain K56-2, a polymyxin B-sensitive K56-2 mutant strain with heptoseless lipopolysaccharide (LPS) (RSF34), and a derivative of RSF34 (RSF34 4000B) isolated through multiple rounds of selection in polymyxin B that despite having a heptoseless LPS is highly polymyxin B-resistant. Results A heptoseless LPS mutant of B. cenocepacia was passaged through multiple rounds of selection to regain high levels of polymyxin B-resistance. This process resulted in various phenotypic changes in the isolate that could contribute to polymyxin B resistance and are consistent with LPS-independent changes in the outer membrane. The transcriptional response of three B. cenocepacia strains to subinhibitory concentrations of polymyxin B was analyzed using microarray analysis and validated by quantitative Real Time-PCR. There were numerous baseline changes in expression between the three strains in the absence of polymyxin B. In both K56-2 and RSF34, similar transcriptional changes upon treatment with polymyxin B were found and included upregulation of various genes that may be involved in polymyxin B resistance and downregulation of genes required for the synthesis and operation of flagella. This last result was validated phenotypically as both swimming and swarming motility were impaired in the presence of polymyxin B. RSF34 4000B had altered the expression in a larger number of genes upon treatment with polymyxin B than either K56-2 or RSF34, but the relative fold-changes in expression were lower. Conclusions It is possible to generate polymyxin B-resistant isolates from polymyxin B-sensitive mutant strains of B. cenocepacia, likely due to the multifactorial nature of polymyxin B resistance of this bacterium. Microarray analysis showed that B. cenocepacia mounts multiple transcriptional responses following exposure to polymyxin B. Polymyxin B-regulated genes identified in this study may be required for polymyxin B resistance, which must be tested experimentally. Exposure to polymyxin B also decreases expression of flagellar genes resulting in reduced swimming and swarming motility.
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Affiliation(s)
- Slade A Loutet
- Centre for Human Immunology, Department of Microbiology and Immunology, the University of Western Ontario, London, Ontario, Canada
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17
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Loutet SA, Valvano MA. Extreme antimicrobial peptide and polymyxin B resistance in the genus Burkholderia. Front Cell Infect Microbiol 2011; 1:6. [PMID: 22919572 PMCID: PMC3417367 DOI: 10.3389/fcimb.2011.00006] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 07/12/2011] [Indexed: 12/12/2022] Open
Abstract
Cationic antimicrobial peptides and polymyxins are a group of naturally occurring antibiotics that can also possess immunomodulatory activities. They are considered a new source of antibiotics for treating infections by bacteria that are resistant to conventional antibiotics. Members of the genus Burkholderia, which includes various human pathogens, are inherently resistant to antimicrobial peptides. The resistance is several orders of magnitude higher than that of other Gram-negative bacteria such as Escherichia coli, Salmonella enterica, or Pseudomonas aeruginosa. This review summarizes our current understanding of antimicrobial peptide and polymyxin B resistance in the genus Burkholderia. These bacteria possess major and minor resistance mechanisms that will be described in detail. Recent studies have revealed that many other emerging Gram-negative opportunistic pathogens may also be inherently resistant to antimicrobial peptides and polymyxins and we propose that Burkholderia sp. are a model system to investigate the molecular basis of the resistance in extremely resistant bacteria. Understanding resistance in these types of bacteria will be important if antimicrobial peptides come to be used regularly for the treatment of infections by susceptible bacteria because this may lead to increased resistance in the species that are currently susceptible and may also open up new niches for opportunistic pathogens with high inherent resistance.
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Affiliation(s)
- Slade A Loutet
- Centre for Human Immunology, University of Western Ontario London, Ontario, Canada
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18
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Loutet SA, Valvano MA. Extreme antimicrobial Peptide and polymyxin B resistance in the genus burkholderia. Front Microbiol 2011; 2:159. [PMID: 21811491 PMCID: PMC3143681 DOI: 10.3389/fmicb.2011.00159] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2011] [Accepted: 07/12/2011] [Indexed: 01/04/2023] Open
Abstract
Cationic antimicrobial peptides and polymyxins are a group of naturally occurring antibiotics that can also possess immunomodulatory activities. They are considered a new source of antibiotics for treating infections by bacteria that are resistant to conventional antibiotics. Members of the genus Burkholderia, which includes various human pathogens, are inherently resistant to antimicrobial peptides. The resistance is several orders of magnitude higher than that of other Gram-negative bacteria such as Escherichia coli, Salmonella enterica, or Pseudomonas aeruginosa. This review summarizes our current understanding of antimicrobial peptide and polymyxin B resistance in the genus Burkholderia. These bacteria possess major and minor resistance mechanisms that will be described in detail. Recent studies have revealed that many other emerging Gram-negative opportunistic pathogens may also be inherently resistant to antimicrobial peptides and polymyxins and we propose that Burkholderia sp. are a model system to investigate the molecular basis of the resistance in extremely resistant bacteria. Understanding resistance in these types of bacteria will be important if antimicrobial peptides come to be used regularly for the treatment of infections by susceptible bacteria because this may lead to increased resistance in the species that are currently susceptible and may also open up new niches for opportunistic pathogens with high inherent resistance.
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Affiliation(s)
- Slade A Loutet
- Centre for Human Immunology, University of Western Ontario London, ON, Canada
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19
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Loutet SA, Mussen LE, Flannagan RS, Valvano MA. A two-tier model of polymyxin B resistance in Burkholderia cenocepacia. ENVIRONMENTAL MICROBIOLOGY REPORTS 2011; 3:278-285. [PMID: 23761261 DOI: 10.1111/j.1758-2229.2010.00222.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Burkholderia cenocepacia is an environmental bacterium causing serious human opportunistic infections and is extremely resistant to multiple antibiotics including antimicrobial peptides, such as polymyxin B (PmB). Extreme antibiotic resistance is attributed to outer membrane impermeability ('intrinsic' resistance). Previous work showed that production of full-length lipopolysaccharide (LPS) prevents surface binding of PmB. We hypothesized that two tiers of resistance mechanisms rendering different thresholds of PmB resistance exist in B. cenocepacia. To test this notion, candidate genes were mutated in two isogenic strains expressing full-length LPS or truncated LPS devoid of heptose ('heptoseless LPS') respectively. We uncovered various proteins required for PmB resistance only in the strain with heptoseless LPS. These proteins are not involved in preventing PmB binding to whole cells or permeabilization of the outer membrane. Our results support a two-tier model of PmB resistance in B. cenocepacia. One tier sets a very high threshold mediated by the LPS and the outer membrane permeability barrier. The second tier sets a lower threshold that may play a role in PmB resistance only when outer membrane permeability is compromised. This model may be of general applicability to understanding the high antimicrobial peptide resistance of environmental opportunistic pathogens.
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Affiliation(s)
- Slade A Loutet
- Centre for Human Immunology, Department of Microbiology and Immunology, University of Western Ontario, London, ON, Canada N6A 5C1 Department of Medicine, University of Western Ontario, London, ON, Canada N6A 5C1
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20
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Döring G, Parameswaran IG, Murphy TF. Differential adaptation of microbial pathogens to airways of patients with cystic fibrosis and chronic obstructive pulmonary disease. FEMS Microbiol Rev 2011; 35:124-46. [PMID: 20584083 DOI: 10.1111/j.1574-6976.2010.00237.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cystic fibrosis (CF), the most common autosomal recessive disorder in Caucasians, and chronic obstructive pulmonary disease (COPD), a disease of adults, are characterized by chronic lung inflammation, airflow obstruction and extensive tissue remodelling, which have a major impact on patients' morbidity and mortality. Airway inflammation is stimulated in CF by chronic bacterial infections and in COPD by environmental stimuli, particularly from smoking. Pseudomonas aeruginosa is the major bacterial pathogen in CF, while in COPD, Haemophilus influenzae is most frequently observed. Molecular studies indicate that during chronic pulmonary infection, P. aeruginosa clones genotypically and phenotypically adapt to the CF niche, resulting in a highly diverse bacterial community that is difficult to eradicate therapeutically. Pseudomonas aeruginosa clones from COPD patients remain within the airways only for limited time periods, do not adapt and are easily eradicated. However, in a subgroup of severely ill COPD patients, P. aeruginosa clones similar to those in CF persist. In this review, we will discuss the pathophysiology of lung disease in CF and COPD, the complex genotypic and phenotypic adaptation processes of the opportunistic bacterial pathogens and novel treatment options.
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Affiliation(s)
- Gerd Döring
- Institute of Medical Microbiology and Hygiene, Universitätsklinikum Tübingen, Tübingen, Germany.
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21
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Abstract
With more antibiotic resistance and emerging pathogens in cystic fibrosis (CF) patients, the need for new strategies in the lifelong treatment of pulmonary infection has increased. Most of the focus is on chronic infection with Pseudomonas aeruginosa, which is still thought to be the main pathogen leading to advanced CF lung disease. Other bacterial species are also recognized in the pathogenesis of CF lung disease, even though their definitive role is not well established yet. Clearly, expansion of treatment options is urgently needed. This article focuses on recent developments in the field of new antimicrobial strategies for CF. It is clear that studies on new classes of antibiotics or antimicrobial-like drugs are scarce, and that most studies involve new (inhalation) formulations, new routes of delivery, or analogs of existing classes of antibiotics. Studies of new antibiotic-like drugs are, in most cases, in preclinical phases of development and only a few of these agents may reach the market. Importantly, new inhaled antibiotics, e.g. aztreonam, levofloxacin, and fosfomycin, and new, more efficient delivery systems such as dry powder inhalation and liposomes for current antibiotics are in the clinical phase of development. These developments will be of great importance in improving effective treatment and reducing the treatment burden for CF patients in the near future.
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Affiliation(s)
- Mireille van Westreenen
- Department of Medical Microbiology & Infectious Diseases, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, the Netherlands.
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22
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Kooi C, Sokol PA. Burkholderia cenocepacia zinc metalloproteases influence resistance to antimicrobial peptides. MICROBIOLOGY-SGM 2009; 155:2818-2825. [PMID: 19542010 DOI: 10.1099/mic.0.028969-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Burkholderia cenocepacia secretes two zinc-dependent metalloproteases, designated ZmpA and ZmpB. Previously, ZmpA and ZmpB have been shown to cleave several proteins important in host defence. In this study, the ability of ZmpA and ZmpB to digest and inactivate antimicrobial peptides involved in innate immunity was examined. ZmpB but not ZmpA cleaved beta-defensin-1. ZmpA but not ZmpB cleaved the cathelicidin LL-37. Both enzymes cleaved elafin and secretory leukocyte inhibitor, which are antimicrobial peptides as well as neutrophil elastase inhibitors. Both ZmpA and ZmpB cleaved protamine, a fish antimicrobial peptide, and a zmpA zmpB mutant was more sensitive to protamine killing than the parental strain. ZmpA or ZmpB cleavage of elafin inactivated its anti-protease activity. The effect of ZmpA and ZmpB on the neutrophil proteases elastase and cathepsin G was also examined but neither enzyme was active against these host proteases. These studies suggest that ZmpA and ZmpB may influence the resistance of B. cenocepacia to host antimicrobial peptides as well as alter the host protease/anti-protease balance in chronic respiratory infections.
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Affiliation(s)
- Cora Kooi
- Department of Microbiology and Infectious Diseases, University of Calgary, Calgary AB T2N 4N1, Canada
| | - Pamela A Sokol
- Department of Microbiology and Infectious Diseases, University of Calgary, Calgary AB T2N 4N1, Canada
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23
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Ortega X, Silipo A, Saldías MS, Bates CC, Molinaro A, Valvano MA. Biosynthesis and structure of the Burkholderia cenocepacia K56-2 lipopolysaccharide core oligosaccharide: truncation of the core oligosaccharide leads to increased binding and sensitivity to polymyxin B. J Biol Chem 2009; 284:21738-51. [PMID: 19525227 DOI: 10.1074/jbc.m109.008532] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Burkholderia cenocepacia is an opportunistic pathogen that displays a remarkably high resistance to antimicrobial peptides. We hypothesize that high resistance to antimicrobial peptides in these bacteria is because of the barrier properties of the outer membrane. Here we report the identification of genes for the biosynthesis of the core oligosaccharide (OS) moiety of the B. cenocepacia lipopolysaccharide. We constructed a panel of isogenic mutants with truncated core OS that facilitated functional gene assignments and the elucidation of the core OS structure in the prototypic strain K56-2. The core OS structure consists of three heptoses in the inner core region, 3-deoxy-d-manno-octulosonic acid, d-glycero-d-talo-octulosonic acid, and 4-amino-4-deoxy-l-arabinose linked to d-glycero-d-talo-octulosonic acid. Also, glucose is linked to heptose I, whereas heptose II carries a second glucose and a terminal heptose, which is the site of attachment of the O antigen. We established that the level of core truncation in the mutants was proportional to their increased in vitro sensitivity to polymyxin B (PmB). Binding assays using fluorescent 5-dimethylaminonaphthalene-1-sulfonyl-labeled PmB demonstrated a correlation between sensitivity and increased binding of PmB to intact cells. Also, the mutant producing a heptoseless core OS did not survive in macrophages as compared with the parental K56-2 strain. Together, our results demonstrate that a complete core OS is required for full PmB resistance in B. cenocepacia and that resistance is due, at least in part, to the ability of B. cenocepacia to prevent binding of the peptide to the bacterial cell envelope.
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Affiliation(s)
- Ximena Ortega
- Infectious Diseases Research Group, Siebens-Drake Research Institute, Department of Microbiology and Immunology, University of Western Ontario, London, Ontario N6A 5C1, Canada
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24
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Altman E, Wang Z, Aaron SD, Liu X, Vandemheen KL, Ferris W, Giesbrecht T, Li J. Epidemiological investigation and glycotyping of clinical Pseudomonas aeruginosa isolates from patients with cystic fibrosis by mass spectrometry: Association with multiple drug resistance. J Microbiol Methods 2009; 76:204-8. [DOI: 10.1016/j.mimet.2008.10.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 10/06/2008] [Accepted: 10/07/2008] [Indexed: 11/26/2022]
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25
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De Soyza A, Silipo A, Lanzetta R, Govan JR, Molinaro A. Chemical and biological features of Burkholderia cepacia complex lipopolysaccharides. Innate Immun 2008; 14:127-44. [PMID: 18562572 DOI: 10.1177/1753425908093984] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The Burkholderia cepacia complex comprises 10 closely related Gram-negative organisms all of which appear capable of causing disease in humans. These organisms appear of particular relevance to patients with cystic fibrosis. Lipopolysaccharide (LPS) is an important virulence determinant in Gram-negative pathogens. In this review, we highlight important data within the field commenting on LPS/lipid A structure-to-function relationships and cytokine induction capacity of Burkholderia strains studied so far.
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Affiliation(s)
- Anthony De Soyza
- Transplantation and Immunobiology Group, Institute of Cellular Medicine, Newcastle University and The Freeman Hospital, Newcastle-upon-Tyne, UK.
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26
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The genome of Burkholderia cenocepacia J2315, an epidemic pathogen of cystic fibrosis patients. J Bacteriol 2008; 191:261-77. [PMID: 18931103 PMCID: PMC2612433 DOI: 10.1128/jb.01230-08] [Citation(s) in RCA: 273] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Bacterial infections of the lungs of cystic fibrosis (CF) patients cause major complications in the treatment of this common genetic disease. Burkholderia cenocepacia infection is particularly problematic since this organism has high levels of antibiotic resistance, making it difficult to eradicate; the resulting chronic infections are associated with severe declines in lung function and increased mortality rates. B. cenocepacia strain J2315 was isolated from a CF patient and is a member of the epidemic ET12 lineage that originated in Canada or the United Kingdom and spread to Europe. The 8.06-Mb genome of this highly transmissible pathogen comprises three circular chromosomes and a plasmid and encodes a broad array of functions typical of this metabolically versatile genus, as well as numerous virulence and drug resistance functions. Although B. cenocepacia strains can be isolated from soil and can be pathogenic to both plants and man, J2315 is representative of a lineage of B. cenocepacia rarely isolated from the environment and which spreads between CF patients. Comparative analysis revealed that ca. 21% of the genome is unique in comparison to other strains of B. cenocepacia, highlighting the genomic plasticity of this species. Pseudogenes in virulence determinants suggest that the pathogenic response of J2315 may have been recently selected to promote persistence in the CF lung. The J2315 genome contains evidence that its unique and highly adapted genetic content has played a significant role in its success as an epidemic CF pathogen.
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Abstract
The global emergence of multidrug-resistant gram-negative bacilli has spurred a renewed interest in polymyxins. Once discarded due to concerns regarding nephrotoxicity and neurotoxicity, polymyxins now hold an important role in the antibiotic armamentarium. However, more reliable information is needed to determine the optimal dosing of these agents. Also, unanswered questions regarding in vitro testing remain, including questions regarding the reliability of automated systems and the establishment of appropriate breakpoints for defining susceptibility. Most contemporary clinical studies examining the use of these agents have involved patients with infections due to multidrug-resistant Pseudomonas aeruginosa and Acinetobacter baumannii strains. It has been reassuring that polymyxin therapy for resistant bacteria has resulted in clinical responses and toxicity rates similar to those for carbapenem therapy for susceptible isolates. While most surveillance studies demonstrated high rates of susceptibility, several reports noted the emergence of polymyxin-resistant nosocomial pathogens. Polymyxins have assumed an important antibiotic niche for therapy for hospital-acquired infections; further studies defining the optimal use of these agents will likely extend the duration of their clinical usefulness.
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28
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Pauwels K, Van Gelder P. Affinity-based isolation of a bacterial lipase through steric chaperone interactions. Protein Expr Purif 2008; 59:342-8. [DOI: 10.1016/j.pep.2008.03.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2008] [Accepted: 03/02/2008] [Indexed: 10/22/2022]
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29
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30
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Ortega XP, Cardona ST, Brown AR, Loutet SA, Flannagan RS, Campopiano DJ, Govan JRW, Valvano MA. A putative gene cluster for aminoarabinose biosynthesis is essential for Burkholderia cenocepacia viability. J Bacteriol 2007; 189:3639-44. [PMID: 17337576 PMCID: PMC1855895 DOI: 10.1128/jb.00153-07] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Using a conditional mutagenesis strategy we demonstrate here that a gene cluster encoding putative aminoarabinose (Ara4N) biosynthesis enzymes is essential for the viability of Burkholderia cenocepacia. Loss of viability is associated with dramatic changes in bacterial cell morphology and ultrastructure, increased permeability to propidium iodide, and sensitivity to sodium dodecyl sulfate, suggesting a general cell envelope defect caused by the lack of Ara4N.
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Affiliation(s)
- Ximena P Ortega
- Department of Microbiology and Immunology, Infectious Diseases Research Group, Siebens-Drake Medical Research Institute, University of Western Ontario, London, Ontario, Canada
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31
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Kwakman PHS, te Velde AA, Vandenbroucke-Grauls CMJE, van Deventer SJH, Zaat SAJ. Treatment and prevention of Staphylococcus epidermidis experimental biomaterial-associated infection by bactericidal peptide 2. Antimicrob Agents Chemother 2006; 50:3977-83. [PMID: 17000746 PMCID: PMC1693978 DOI: 10.1128/aac.00575-06] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Biomaterial-associated infections (BAI) are the major cause of failure of indwelling medical devices and are predominantly caused by staphylococci, especially Staphylococcus epidermidis. We investigated the in vitro microbicidal activity of the synthetic antimicrobial peptide bactericidal peptide 2 (BP2) and its efficacy in a murine model of S. epidermidis BAI. BP2 showed potent microbicidal activity at micromolar concentrations against a broad spectrum of microorganisms, including antibiotic-resistant bacteria. The staphylocidal activity of BP2 was not affected by physiological salt concentrations and was only slightly affected by the presence of human plasma. In the BAI model, injection of BP2 (5 mg/kg of body weight) 1 h after challenge with S. epidermidis resulted in an 80% reduction in the number of culture-positive implants and a 100-fold reduction in survival of S. epidermidis in peri-implant tissue at 24 h postchallenge. When BP2 was injected along implants 3 h prior to bacterial challenge, the median numbers of CFU cultured from biomaterial implants and peri-implant tissue were reduced by 85% and 90%, respectively. In conclusion, BP2 has potent, broad-spectrum in vitro microbicidal activity and showed potent in vivo activity in a murine model of S. epidermidis biomaterial-associated infection.
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Affiliation(s)
- Paulus H S Kwakman
- Department of Medical Microbiology, Academic Medical Center, University of Amsterdam, The Netherlands
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32
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Tzeng YL, Ambrose KD, Zughaier S, Zhou X, Miller YK, Shafer WM, Stephens DS. Cationic antimicrobial peptide resistance in Neisseria meningitidis. J Bacteriol 2005; 187:5387-96. [PMID: 16030233 PMCID: PMC1196002 DOI: 10.1128/jb.187.15.5387-5396.2005] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2005] [Accepted: 05/04/2005] [Indexed: 11/20/2022] Open
Abstract
Cationic antimicrobial peptides (CAMPs) are important components of the innate host defense system against microbial infections and microbial products. However, the human pathogen Neisseria meningitidis is intrinsically highly resistant to CAMPs, such as polymyxin B (PxB) (MIC > or = 512 microg/ml). To ascertain the mechanisms by which meningococci resist PxB, mutants that displayed increased sensitivity (> or =4-fold) to PxB were identified from a library of mariner transposon mutants generated in a meningococcal strain, NMB. Surprisingly, more than half of the initial PxB-sensitive mutants had insertions within the mtrCDE operon, which encodes proteins forming a multidrug efflux pump. Additional PxB-sensitive mariner mutants were identified from a second round of transposon mutagenesis performed in an mtr efflux pump-deficient background. Further, a mutation in lptA, the phosphoethanolamine (PEA) transferase responsible for modification of the lipid A head groups, was identified to cause the highest sensitivity to PxB. Mutations within the mtrD or lptA genes also increased meningococcal susceptibility to two structurally unrelated CAMPs, human LL-37 and protegrin-1. Consistently, PxB neutralized inflammatory responses elicited by the lptA mutant lipooligosaccharide more efficiently than those induced by wild-type lipooligosaccharide. mariner mutants with increased resistance to PxB were also identified in NMB background and found to contain insertions within the pilMNOPQ operon involved in pilin biogenesis. Taken together, these data indicated that meningococci utilize multiple mechanisms including the action of the MtrC-MtrD-MtrE efflux pump and lipid A modification as well as the type IV pilin secretion system to modulate levels of CAMP resistance. The modification of meningococcal lipid A head groups with PEA also prevents neutralization of the biological effects of endotoxin by CAMP.
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Affiliation(s)
- Yih-Ling Tzeng
- Department of Veterans Affairs Medical Center, Research 151, Room 5A188, 1670 Clairmont Road, Decatur, GA 30033, USA
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33
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Mahenthiralingam E, Urban TA, Goldberg JB. The multifarious, multireplicon Burkholderia cepacia complex. Nat Rev Microbiol 2005; 3:144-56. [PMID: 15643431 DOI: 10.1038/nrmicro1085] [Citation(s) in RCA: 622] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The Burkholderia cepacia complex (Bcc) is a collection of genetically distinct but phenotypically similar bacteria that are divided into at least nine species. Bcc bacteria are found throughout the environment, where they can have both beneficial and detrimental effects on plants and some members can also degrade natural and man-made pollutants. Bcc bacteria are now recognized as important opportunistic pathogens that can cause variable lung infections in cystic fibrosis patients, which result in asymptomatic carriage, chronic infection or 'cepacia syndrome', which is characterized by a rapid decline in lung function that can include invasive disease. Here we highlight the unique characteristics of the Bcc, focusing on the factors that determine virulence.
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Helander IM, Haikara A, Sadovskaya I, Vinogradov E, Salkinoja-Salonen MS. Lipopolysaccharides of anaerobic beer spoilage bacteria of the genusPectinatus– lipopolysaccharides of a Gram-positive genus. FEMS Microbiol Rev 2004; 28:543-52. [PMID: 15539073 DOI: 10.1016/j.femsre.2004.05.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2004] [Revised: 04/07/2004] [Accepted: 05/11/2004] [Indexed: 11/18/2022] Open
Abstract
Bacteria of the genus Pectinatus emerged during the seventies as contaminants and spoilage organisms in packaged beer. This genus comprises two species, Pectinatus cerevisiiphilus and Pectinatus frisingensis; both are strict anaerobes. On the basis of genomic properties the genus is placed among low GC Gram-positive bacteria (phylum Firmicutes, class Clostridia, order Clostridiales, family Acidaminococcaceae). Despite this assignment, Pectinatus bacteria possess an outer membrane and lipopolysaccharide (LPS) typical of Gram-negative bacteria. The present review compiles the structural and compositional studies performed on Pectinatus LPS. These lipopolysaccharides exhibit extensive heterogeneity, i.e. several macromolecularly and structurally distinct LPS molecules are produced by each strain. Whereas heterogeneity is a common property in lipopolysaccharides, Pectinatus LPS have been shown to contain exceptional carbohydrate structures, consisting of a fairly conserved core region that carries a large non-repetitive saccharide that probably replaces the O-specific chain. Such structures represent a novel architectural principle of the LPS molecule.
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Affiliation(s)
- Ilkka M Helander
- Division of Microbiology, Department of Applied Chemistry and Microbiology, University of Helsinki, Finland.
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Shimomura H, Matsuura M, Saito S, Hirai Y, Isshiki Y, Kawahara K. Unusual interaction of a lipopolysaccharide isolated from Burkholderia cepacia with polymyxin B. Infect Immun 2003; 71:5225-30. [PMID: 12933868 PMCID: PMC187347 DOI: 10.1128/iai.71.9.5225-5230.2003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2003] [Revised: 05/13/2003] [Accepted: 06/06/2003] [Indexed: 11/20/2022] Open
Abstract
We have demonstrated that lipopolysaccharide (LPS) obtained from Burkholderia cepacia, an important opportunistic pathogen, has unique characteristics in both structure and activity. One of the structural characteristics is that the B. cepacia LPS has 4-amino-4-deoxy-L-arabinose (Ara4N) in its inner core region. Polymyxin B (PmxB) is known to act as an LPS antagonist, but LPS with Ara4N is suggested to be PmxB resistant by decreasing the binding capability of PmxB. Interaction of B. cepacia LPS with PmxB was investigated and compared with that of a reference LPS of Salmonella enterica serovar Abortusequi, referred to hereafter as the reference LPS. B. cepacia LPS suffered no suppressive effect of PmxB in its activity to stimulate murine peritoneal macrophages for induction of tumor necrosis factor alpha (TNF-alpha) and IL-6 even when the activity of the reference LPS was completely suppressed. A characteristic of B. cepacia LPS is that it has selectively weak interleukin-1 beta (IL-1 beta)-inducing activity while activity to induce TNF-alpha and IL-6 has been shown to be as strong as that of the reference LPS. Remarkably, PmxB augmented the IL-1 beta-inducing activity of B. cepacia LPS to the level of that of the reference LPS and, in contrast, completely suppressed the strong activity of the reference LPS. Using PmxB-immobilized beads, the adsorbances of these LPSs to the beads were compared, and it was found that B. cepacia LPS bound to PmxB with a high affinity similar to that of the reference LPS. These results indicate an unusual interaction of B. cepacia LPS with PmxB whereby B. cepacia LPS not only allows the binding of PmxB with high affinity, even though it contains Ara4N, but also suffers no suppressive effect of PmxB on its activity. Moreover, a remarkable increase in its IL-1 beta-inducing activity was also observed.
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Affiliation(s)
- Hirofumi Shimomura
- Division of Bacteriology, Department of Infection and Immunity, Jichi Medical School, Tochigi 239-0498, Japan
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Cox AD, Wright JC, Li J, Hood DW, Moxon ER, Richards JC. Phosphorylation of the lipid A region of meningococcal lipopolysaccharide: identification of a family of transferases that add phosphoethanolamine to lipopolysaccharide. J Bacteriol 2003; 185:3270-7. [PMID: 12754224 PMCID: PMC155371 DOI: 10.1128/jb.185.11.3270-3277.2003] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A gene, NMB1638, with homology to the recently characterized gene encoding a phosphoethanolamine transferase, lpt-3, has been identified from the Neisseria meningitidis genome sequence and was found to be present in all meningococcal strains examined. Homology comparison with other database sequences would suggest that NMB1638 and lpt-3 represent genes coding for members of a family of proteins of related function identified in a wide range of gram-negative species of bacteria. When grown and isolated under appropriate conditions, N. meningitidis elaborated lipopolysaccharide (LPS) containing a lipid A that was characteristically phosphorylated with multiple phosphate and phosphoethanolamine residues. In all meningococcal strains examined, each lipid A species contained the basal diphosphorylated species, wherein a phosphate group is attached to each glucosamine residue. Also elaborated within the population of LPS molecules are a variety of "phosphoforms" that contain either an additional phosphate residue, an additional phosphoethanolamine residue, additional phosphate and phosphoethanolamine residues, or an additional phosphate and two phosphoethanolamine residues in the lipid A. Mass spectroscopic analyses of LPS from three strains in which NMB1638 had been inactivated by a specific mutation indicated that there were no phosphoethanolamine residues included in the lipid A region of the LPS and that there was no further phosphorylation of lipid A beyond one additional phosphate species. We propose that NMB1638 encodes a phosphoethanolamine transferase specific for lipid A and propose naming the gene "lptA," for "LPS phosphoethenolamine transferase for lipid A."
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Affiliation(s)
- Andrew D Cox
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario K1A 0R6, Canada.
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Gronow S, Noah C, Blumenthal A, Lindner B, Brade H. Construction of a deep-rough mutant of Burkholderia cepacia ATCC 25416 and characterization of its chemical and biological properties. J Biol Chem 2003; 278:1647-55. [PMID: 12427755 DOI: 10.1074/jbc.m206942200] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Burkholderia cepacia is a bacterium with increasing importance as a pathogen in patients with cystic fibrosis. The deep-rough mutant Ko2b was generated from B. cepacia type strain ATCC 25416 by insertion of a kanamycin resistance cassette into the gene waaC encoding heptosyltransferase I. Mass spectrometric analysis of the de-O-acylated lipopolysaccharide (LPS) of the mutant showed that it consisted of a bisphosphorylated glucosamine backbone with two 3-hydroxyhexadecanoic acids in amide-linkage, 4-amino-4-deoxyarabinose (Ara4N) residues on both phosphates, and a core oligosaccharide of the sequence Ara4N-(1 --> 8) D-glycero-D-talo-oct-2-ulosonic acid (Ko)-(2 --> 4)3-deoxy-D-manno-oct-2-ulosonic acid (Kdo). The mutant allowed investigations on the biosynthesis of the LPS as well as on its role in human infection. Mutant Ko2b showed no difference in its ability to invade human macrophages as compared with the wild type. Furthermore, isolated LPS of both strains induced the production of tumor necrosis factor alpha from macrophages to the same extent. Thus, the truncation of the LPS did not decrease the biological activity of the mutant or its LPS in these aspects.
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Affiliation(s)
- Sabine Gronow
- Division of Medical and Biochemical Microbiology, Research Center Borstel, Center for Medicine and Biosciences, Parkallee 22, D-23845 Borstel, Germany.
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Russell AD. Bacterial outer membrane and cell wall penetration and cell destruction by polluting chemical agents and physical conditions. Sci Prog 2003; 86:283-311. [PMID: 15508894 PMCID: PMC10367465 DOI: 10.3184/003685003783238608] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In the environment, bacteria and other microorganisms are subjected to a variety of constantly changing chemical and physical agencies. Chemical ones include antimicrobial compounds (both biocides and antibiotics), pollutants, drugs, cosmetic and pharmaceutical ingredients and pesticides. The physical agents include desiccation and drying, osmotic pressure, hydrostatic pressure, temperature and pH changes and radiations (ultraviolet, sunlight, ionizing). Bacteria must thus adapt to survive these inimicable conditions. Organisms such as bacterial spores usually survive, whereas other types of microorganisms may be much more susceptible. Depending on the type of organism, the bacterial cell wall, outer membrane or the spore outer layers may act as permeability barriers to the intracellular uptake of antibiotics and biocides. Some antibacterial agents interact with, and damage or modify, the outer components. Physical agencies are known to damage the cytoplasmic membrane or to produce alterations in DNA or proteins or enzymes. Nevertheless, significant damage to the cell wall or outer membrane may also occur. Four types of organisms are considered: cocci, mycobactria, Gram-negative bacteria and bacterial spores. The nature of the damage inflicted on, or in some cases prevented by, their outer cell layers is discussed for each type of organism.
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Affiliation(s)
- A D Russell
- Welsh School of Pharmacy, Cardiff University, Cardiff CF10 3XF, UK
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Fehlner-Gardiner CC, Valvano MA. Cloning and characterization of the Burkholderia vietnamiensis norM gene encoding a multi-drug efflux protein. FEMS Microbiol Lett 2002; 215:279-83. [PMID: 12399047 DOI: 10.1111/j.1574-6968.2002.tb11403.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Polymyxin B-sensitive mutants in Burkholderia vietnamiensis (Burkholderia cepacia genomovar V) were generated with a mini-Tn5 encoding tetracycline resistance. One of the transposon mutants had an insertion in the norM gene encoding a multi-drug efflux protein. Expression of B. vietnamiensis norM in an Escherichia coli acrAB deletion mutant complemented its norfloxacin hypersensitivity, indicating that the protein functions in drug efflux. However, no effect on antibiotic sensitivity other than sensitivity to polymyxin B was observed in the B. vietnamiensis norM mutant. We demonstrate that increased polymyxin sensitivity in B. vietnamiensis was associated with the presence of tetracycline in the growth medium, a phenotype that was partially suppressed by expression of the norM gene.
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Abstract
Burkholderia cepacia is an important opportunistic pathogen in certain compromised hosts, particularly those with either cystic fibrosis (CF) or chronic granulomatous disease. The "family" of bacteria known as B. cepacia is highly heterogeneous and is composed of at least nine discrete species or genomovars, constituting the B. cepacia complex. Bacteria from the B. cepacia complex are particularly virulent in susceptible hosts, often causing necrotising invasive infection and death. Whereas the microbial determinants of virulence in B. cepacia complex are currently not defined, the bacteria appear to have features facilitating survival within host cells. Burkholderia cepacia is highly resistant to antibiotics and to neutrophil-mediated non-oxidative killing; infection should be treated with combination antimicrobial therapy. Burkholderia cepacia can spread from one CF patient to another. Transmission appears to be facilitated by close personal contact and by certain bacterial factors.
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Affiliation(s)
- David Paul Speert
- Division of Infectious and Immunological Diseases, Department of Pediatrics, University of British Columbia and British Columbia's Children's and Women's Health Centre and the Canadian Bacterial Diseases Network, Research Centre, Vancouver, BC, Canada
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Denyer S, Maillard JY. Cellular impermeability and uptake of biocides and antibiotics in Gram-negative bacteria. J Appl Microbiol 2002. [DOI: 10.1046/j.1365-2672.92.5s1.19.x] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Binding of protegrin-1 to Pseudomonas aeruginosa and Burkholderia cepacia. Respir Res 2002; 3:18. [PMID: 11980587 PMCID: PMC107847 DOI: 10.1186/rr167] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2001] [Revised: 01/29/2002] [Accepted: 01/31/2002] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Pseudomonas aeruginosa and Burkholderia cepacia infections of cystic fibrosis patients' lungs are often resistant to conventional antibiotic therapy. Protegrins are antimicrobial peptides with potent activity against many bacteria, including P. aeruginosa. The present study evaluates the correlation between protegrin-1 (PG-1) sensitivity/resistance and protegrin binding in P. aeruginosa and B. cepacia. METHODS The PG-1 sensitivity/resistance and PG-1 binding properties of P. aeruginosa and B. cepacia were assessed using radial diffusion assays, radioiodinated PG-1, and surface plasmon resonance (BiaCore). RESULTS The six P. aeruginosa strains examined were very sensitive to PG-1, exhibiting minimal active concentrations from 0.0625-0.5 microg/ml in radial diffusion assays. In contrast, all five B. cepacia strains examined were greater than 10-fold to 100-fold more resistant, with minimal active concentrations ranging from 6-10 microg/ml. When incubated with a radioiodinated variant of PG-1, a sensitive P. aeruginosa strain bound considerably more protegrin molecules per cell than a resistant B. cepacia strain. Binding/diffusion and surface plasmon resonance assays revealed that isolated lipopolysaccharide (LPS) and lipid A from the sensitive P. aeruginosa strains bound PG-1 more effectively than LPS and lipid A from resistant B. cepacia strains. CONCLUSION These findings support the hypothesis that the relative resistance of B. cepacia to protegrin is due to a reduced number of PG-1 binding sites on the lipid A moiety of its LPS.
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McCoy AJ, Liu H, Falla TJ, Gunn JS. Identification of Proteus mirabilis mutants with increased sensitivity to antimicrobial peptides. Antimicrob Agents Chemother 2001; 45:2030-7. [PMID: 11408219 PMCID: PMC90596 DOI: 10.1128/aac.45.7.2030-2037.2001] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial peptides (APs) are important components of the innate defenses of animals, plants, and microorganisms. However, some bacterial pathogens are resistant to the action of APs. For example, Proteus mirabilis is highly resistant to the action of APs, such as polymyxin B (PM), protegrin, and the synthetic protegrin analog IB-367. To better understand this resistance, a transposon mutagenesis approach was used to generate P. mirabilis mutants sensitive to APs. Four unique PM-sensitive mutants of P. mirabilis were identified (these mutants were >2 to >128 times more sensitive than the wild type). Two of these mutants were also sensitive to IB-367 (16 and 128 times more sensitive than the wild type). Lipopolysaccharide (LPS) profiles of the PM- and protegrin-sensitive mutants demonstrated marked differences in both the lipid A and O-antigen regions, while the PM-sensitive mutants appeared to have alterations of either lipid A or O antigen. Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis of the wild-type and PM-sensitive mutant lipid A showed species with one or two aminoarabinose groups, while lipid A from the PM- and protegrin-sensitive mutants was devoid of aminoarabinose. When the mutants were streaked on an agar-containing medium, the swarming motility of the PM- and protegrin-sensitive mutants was completely inhibited and the swarming motility of the mutants sensitive to only PM was markedly decreased. DNA sequence analysis of the mutagenized loci revealed similarities to an O-acetyltransferase (PM and protegrin sensitive) and ATP synthase and sap loci (PM sensitive). These data further support the role of LPS modifications as an elaborate mechanism in the resistance of certain bacterial species to APs and suggest that LPS surface charge alterations may play a role in P. mirabilis swarming motility.
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Affiliation(s)
- A J McCoy
- Department of Microbiology, University of Texas Health Science Center at San Antonio, San Antonio, Texas 78229-3900, USA
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Bengoechea JA, Skurnik M. Temperature-regulated efflux pump/potassium antiporter system mediates resistance to cationic antimicrobial peptides in Yersinia. Mol Microbiol 2000; 37:67-80. [PMID: 10931306 DOI: 10.1046/j.1365-2958.2000.01956.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Most bacterial pathogens are resistant to cationic antimicrobial peptides (CAMPs) that are key components of the innate immunity of both vertebrates and invertebrates. In Gram-negative bacteria, the known CAMPs resistance mechanisms involve outer membrane (OM) modifications and specifically those in the lipopolysaccharide (LPS) molecule. Here we report, the characterization of a novel CAMPs resistance mechanism present in Yersinia that is dependent on an efflux pump/potassium antiporter system formed by the RosA and RosB proteins. The RosA/RosB system is activated by a temperature shift to 37 degrees C, but is also induced by the presence of the CAMPs, such as polymyxin B. This is the first report of a CAMPs resistance system that is induced by the presence of CAMPs. It is proposed that the RosA/RosB system protects the bacteria by both acidifying the cytoplasm to prevent the CAMPs action and pumping the CAMPs out of the cell.
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Affiliation(s)
- J A Bengoechea
- Department of Medical Biochemistry, Institute of Biomedicine, University of Turku, Kiinamyllynkatu 10, FIN-20520 Turku, Finland
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Abstract
Antibiotic peptides are a key component of the innate immune systems of most multicellular organisms. Despite broad divergences in sequence and taxonomy, most antibiotic peptides share a common mechanism of action, i.e., membrane permeabilization of the pathogen. This review provides a general introduction to the subject, with emphasis on aspects such as structural types, post-translational modifications, mode of action or mechanisms of resistance. Some of these questions are treated in depth in other reviews in this issue. The review also discusses the role of antimicrobial peptides in nature, including several pathological conditions, as well as recent accounts of their application at the preclinical level.
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Affiliation(s)
- D Andreu
- Department of Organic Chemistry, Universitat de Barcelona, Spain.
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Walsh AG, Matewish MJ, Burrows LL, Monteiro MA, Perry MB, Lam JS. Lipopolysaccharide core phosphates are required for viability and intrinsic drug resistance in Pseudomonas aeruginosa. Mol Microbiol 2000; 35:718-27. [PMID: 10692150 DOI: 10.1046/j.1365-2958.2000.01741.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that is notorious for its intrinsic drug resistance. We have used chemical and genetic techniques to characterize three putative kinase genes that are involved in the addition of phosphate to the inner core region of P. aeruginosa lipopolysaccharide. The first gene is a waaP homologue, whereas the other two (wapP and wapQ) are unique to P. aeruginosa. Repeated attempts using a variety of membrane-stabilizing conditions to generate waaP:Gm (Gm, gentamicin) or wapP:Gm mutants were unsuccessful. We were able to generate a chromosomal waaP mutant that had a wild-type copy of either waaPPa or waaPEc in trans, but were unable to cure this plasmid-borne copy of the gene. These results are consistent with the fact that P. aeruginosa mutants lacking inner core heptose (Hep) or phosphate have never been isolated and demonstrate the requirement of Hep-linked phosphate for P. aeruginosa viability. A wapQ:Gm mutant was isolated and it had an unaltered minimum inhibitory concentration (MIC) for novobiocin and only a small decrease in the MIC for sodium dodecyl sulphate (SDS), suggesting that the loss of a phosphate group transferred by WapQ may only be having a small impact on outer-membrane permeability. Nuclear magnetic resonance and methylation linkage analysis showed that WaaPPa could add one phosphate to O4 of HepI in a Salmonella typhimurium waaP mutant. The expression of WaaPPa increased the outer-membrane integrity of these complemented mutants, as evidenced by 35-fold and 75-fold increases in the MIC for novobiocin and SDS respectively. The S. typhimurium waaP mutant transformed with both waaP and wapP had over 250-fold and 1000-fold increases, respectively, in these MICs. The inner core phosphates of P. aeruginosa appear to be playing a key role in the intrinsic drug resistance of this bacterium.
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Affiliation(s)
- A G Walsh
- Department of Microbiology, University of Guelph, Guelph, ON N1G 2W1, Canada
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Abstract
Bacterial resistance to antibiotics is a long-established, widely-studied problem. Increasingly, attention is being directed to the responses of various types of microbes to biocides (antiseptics, disinfectants and preservatives). Different groups of bacteria vary in their susceptibility to biocides, with bacterial spores being the most resistant, followed by mycobacteria, then Gram-negative organisms, with cocci generally being the most sensitive. There are wide divergencies within this general classification. Thus, (i) spores of Bacillus subtilis are less susceptible to biocides than those of Clostridium difficile: (ii) Mycobacterium chelonae strains may show high resistance to glutaraldehyde and M. avium intracellulare is generally less sensitive than M. tuberculosis; (iii) Gram-negative bacteria such as Pseudomonas aeruginosa, Providencia spp and Proteus spp may be difficult to inactivate; (iv) enterococci are less sensitive than staphylococci to biocides and antibiotic-resistant strains of Staphylococcus aureus might show low-level biocide resistance. The mechanisms involved in biocide resistance to biocides are becoming better understood. Intrinsic resistance (intrinsic insusceptibility) is found with bacterial spores, mycobacteria and Gram-negative bacteria. This resistance might, in some instances, be associated with constitutive degradative enzymes but in reality is more closely linked to cellular impermeability. The coats(s) and, to some extent, the cortex in spores, the arabinogalactan and possibly other components of the mycobacterial cell wall and the outer membrane of Gram-negative bacteria limit the concentration of active biocide that can reach the target site(s) in these bacterial cells. A special situation is found with bacteria present in biofilms, which can be considered as being an intrinsic resistance mechanism resulting from physiological (phenotypic) adaptation of cells. Acquired resistance to biocides may arise by cellular mutation or by the acquisition of genetic elements. Plasmid/transposon-mediated resistance to inorganic and organic mercury compounds by hydrolases and reductases has been extensively studied. Plasmid-mediated resistance to some other biocides in Gram-negative bacteria and in staphylococci has been described, but its significance remains uncertain. As to the future, there is a need to establish conclusively whether there is a clear-cut linkage between antibiotic and biocide resistance in non-sporulating bacteria and whether biocides can select for antibiotic resistance. Additionally, the responses to biocides of new and emerging pathogens must be assessed. At the same time, continuing research is necessary to establish further the underlying mechanisms of resistance and to provide more efficient means of bacterial inactivation.
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Affiliation(s)
- A D Russell
- Welsh School of Pharmacy, Cardiff University, Cardiff
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Speert DP, Steen B, Halsey K, Kwan E. A murine model for infection with Burkholderia cepacia with sustained persistence in the spleen. Infect Immun 1999; 67:4027-32. [PMID: 10417170 PMCID: PMC96694 DOI: 10.1128/iai.67.8.4027-4032.1999] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Burkholderia cepacia is an opportunistic pathogen that causes severe systemic infections in patients with chronic granulomatous disease (CGD) or with cystic fibrosis (CF), but its mechanisms of virulence are poorly understood. We developed a murine model of systemic infection in wild-type (WT) and gamma interferon knockout (GKO) BALB/c mice to facilitate dissection of components of pathogenicity and host defense. Both WT and GKO mice were susceptible to chronic splenic infection with B. cepacia, but not with Pseudomonas aeruginosa. B. cepacia strains from patients with CGD persisted longer than those from CF patients. C57BL/6 mice were the most susceptible murine strain; bacteria persisted in the spleen for 2 months. DBA/2, BALB/c, and A/J strains of mice were relatively resistant to infection. Certain strains of B. cepacia complex can persist in the murine spleen after systemic infection; this may provide clues to its virulence in compromised hosts, such as those with CGD and CF.
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Affiliation(s)
- D P Speert
- Division of Infectious and Immunological Diseases, Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada V5Z 4H4.
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