1
|
Paredes-Amaya CC, Ulloa MT, García-Angulo VA. Fierce poison to others: the phenomenon of bacterial dependence on antibiotics. J Biomed Sci 2023; 30:67. [PMID: 37574554 PMCID: PMC10424368 DOI: 10.1186/s12929-023-00963-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/07/2023] [Indexed: 08/15/2023] Open
Abstract
Beyond the development of resistance, the effects of antibiotics on bacteria and microbial communities are complex and far from exhaustively studied. In the context of the current global antimicrobial resistance crisis, understanding the adaptive and physiological responses of bacteria to antimicrobials is of paramount importance along with the development of new therapies. Bacterial dependence on antibiotics is a phenomenon in which antimicrobials instead of eliminating the pathogens actually provide a boost for their growth. This trait comprises an extreme example of the complexities of responses elicited by microorganisms to these drugs. This compelling evolutionary trait was readily described along with the first wave of antibiotics use and dependence to various antimicrobials has been reported. Nevertheless, current molecular characterizations have been focused on dependence on vancomycin, linezolid and colistin, three critically important antibiotics frequently used as last resource therapy for multi resistant pathogens. Outstanding advances have been made in understanding the molecular basis for the dependence to vancomycin, including specific mutations involved. Regarding linezolid and colistin, the general physiological components affected by the dependence, namely ribosomes and membrane function respectively, have been established. Nonetheless the implications of antibiotic dependence in clinically relevant features, such as virulence, epidemics, relationship with development of resistance, diagnostics and therapy effectiveness require clarification. This review presents a brief introduction of the phenomenon of bacterial dependence to antibiotics and a summary on early and current research concerning the basis for this trait. Furthermore, the available information on the effect of dependence in key clinical aspects is discussed. The studies performed so far underline the need to fully disclose the biological and clinical significance of this trait in pathogens to successfully assess its role in resistance and to design adjusted therapies.
Collapse
Affiliation(s)
- Claudia C Paredes-Amaya
- Microbiology Department, Escuela de Ciencias Básicas, Facultad de Salud, Universidad del Valle, Cali, Colombia
| | - María Teresa Ulloa
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile
- Vertebral I+D+i - Corporation for Assistance for Burned Children (Coaniquem), Santiago, Chile
| | - Víctor Antonio García-Angulo
- Microbiology and Micology Program, Facultad de Medicina, Instituto de Ciencias Biomédicas, Universidad de Chile, Independencia 1027, Independencia, RM, Santiago, Chile.
| |
Collapse
|
2
|
In Vitro Pharmacokinetics of LL-37 and Oncorhyncin II Combination Against Acinetobacter baumannii. Jundishapur J Microbiol 2023. [DOI: 10.5812/jjm-131299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Background: Multidrug-resistant (MDR) Acinetobacter baumannii is one of the most common nosocomial pathogens. Antimicrobial peptides (AMPs) have been introduced as a viable alternative to antibiotics in the treatment of MDR pathogens. Objectives: This study was designed to assess the in vitro pharmacokinetics of the combination of two potent AMPs, LL-37 and oncorhyncin II, against A. baumannii (ATCC19606). Methods: The synthesized genes of oncorhyncin II and LL-37 were introduced into Escherichia coli BL21 as the expression host. The minimum inhibitory concentration (MIC), time-kills, and growth kinetics of these peptides were used to evaluate their antimicrobial efficiencies against A. baumannii (ATCC19606). Results: LL-37 and oncorhyncin II recombinant peptides showed MIC of 30.6 and 95.87 µg/mL against A. baumannii, respectively. Additive action was confirmed by combining the generated AMPs at the checkerboard approach. The combination of LL-37 and oncorhyncin II at 2 × MIC resulted in a rapid drop in log10 CFU/mL of A. baumannii in the time-kill and growth kinetic findings studies. Conclusions: The combination of the produced LL-37 and oncorhyncin II synergizes the bioactivity of the individual peptides. Therefore, these peptides or their combinations might function as novel antibiotics and be used to develop and produce new antimicrobial drugs for the treatment of infections caused by A. baumannii.
Collapse
|
3
|
Kamoshida G, Yamada N, Nakamura T, Yamaguchi D, Kai D, Yamashita M, Hayashi C, Kanda N, Sakaguchi M, Morimoto H, Sawada T, Okada T, Kaya Y, Takemoto N, Yahiro K. Preferential Selection of Low-Frequency, Lipopolysaccharide-Modified, Colistin-Resistant Mutants with a Combination of Antimicrobials in Acinetobacter baumannii. Microbiol Spectr 2022; 10:e0192822. [PMID: 36173297 PMCID: PMC9602988 DOI: 10.1128/spectrum.01928-22] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/13/2022] [Indexed: 12/31/2022] Open
Abstract
Colistin, which targets lipopolysaccharide (LPS), is used as a last-resort drug against severe infections caused by drug-resistant Acinetobacter baumannii. However, A. baumannii possesses two colistin-resistance mechanisms. LPS modification caused by mutations in pmrAB genes is often observed in clinical isolates of multidrug-resistant Gram-negative pathogens. In addition to LPS modification, A. baumannii has a unique colistin resistance mechanism, a complete loss of LPS due to mutations in the lpxACD genes, which are involved in LPS biosynthesis. This study aimed to elucidate the detailed mechanism of the emergence of colistin-resistant A. baumannii using strains with the same genetic background. Various colistin-resistant strains were generated experimentally using colistin alone and in combination with other antimicrobials, such as meropenem and ciprofloxacin, and the mutation spectrum was analyzed. In vitro selection of A. baumannii in the presence of colistin led to the emergence of strains harboring mutations in lpxACD genes, resulting in LPS-deficient colistin-resistant strains. However, combination of colistin with other antimicrobials led to the selection of pmrAB mutant strains, resulting in strains with modified LPS (LPS-modified strains). Further, the LPS-deficient strains showed decreased fitness and increased susceptibility to many antibiotics and disinfectants. As LPS-deficient strains have a higher biological cost than LPS-modified strains, our findings suggested that pmrAB mutants are more likely to be isolated in clinical settings. We provide novel insights into the mechanisms of resistance to colistin and provide substantial solutions along with precautions for facilitating current research and treatment of colistin-resistant A. baumannii infections. IMPORTANCE Acinetobacter baumannii has developed resistance to various antimicrobial drugs, and its drug-resistant strains cause nosocomial infections. Controlling these infections has become a global clinical challenge. Carbapenem antibiotics are the frontline treatment drugs for infectious diseases caused by A. baumannii. For patients with infections caused by carbapenem-resistant A. baumannii, colistin-based therapy is often the only treatment option. However, A. baumannii readily acquires resistance to colistin. Many patients infected with colistin-resistant A. baumannii undergo colistin treatment before isolation of the colistin-resistant strain, and it is hypothesized that colistin resistance predominantly emerges under selective pressure during colistin therapy. Although the concomitant use of colistin and carbapenems has been reported to have a synergistic effect in vitro against carbapenem-resistant A. baumannii strains, our observations strongly suggest the need for attention to the emergence of strains with a modified lipopolysaccharide during treatment.
Collapse
Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Noriteru Yamada
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Tomoka Nakamura
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Daiki Yamaguchi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Daichi Kai
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Maho Yamashita
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Chiaki Hayashi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Nana Kanda
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Moe Sakaguchi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Hitoshi Morimoto
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Teppei Sawada
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Tomoko Okada
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yuki Kaya
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Norihiko Takemoto
- Pathogenic Microbe Laboratory, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Kinnosuke Yahiro
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| |
Collapse
|
4
|
Rather IA, Sabir JSM, Asseri AH, Ali S. Antifungal Activity of Human Cathelicidin LL-37, a Membrane Disrupting Peptide, by Triggering Oxidative Stress and Cell Cycle Arrest in Candida auris. J Fungi (Basel) 2022; 8:jof8020204. [PMID: 35205958 PMCID: PMC8875705 DOI: 10.3390/jof8020204] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 02/06/2022] [Accepted: 02/17/2022] [Indexed: 02/07/2023] Open
Abstract
Candida auris, an evolving multidrug-resistant pathogenic yeast, is known for causing severe invasive infections associated with high mortality rates in hospitalized individuals. Distinct from other Candida species, C. auris can persist for longer periods on different surfaces and is resistant to all of the major classes of antifungal drugs. Therefore, there is an urgent need for new antimycotic drugs with improved efficacy and reduced toxicity. The development of new antifungals based on antimicrobial peptides from various sources is considered a promising alternative. In this study, we examined the in vitro anti-yeast activity of the human cathelicidin peptides LL-37 against clinical strains of C. auris alone and in combination with different antifungal drugs by broth microdilution assay. To understand the antifungal mechanism of action, cell envelopes, cell cycle arrest, and effect on oxidative stress enzymes were studied using standard protocols. The minimum inhibitory and fungicidal concentrations of cathelicidin LL-37 ranged from 25–100 and 50–200 µg/mL, respectively. A combination interaction in a 1:1 ratio (cathelicidin LL-37: antifungal drug) resulted in 70% synergy with fluconazole and 100% synergy with amphotericin B and caspofungin. Assessment of the C. auris membrane by using propidium iodide assay after exposure to cathelicidin LL-37 linked membrane permeabilization with inhibition of C. auris cell growth and viability. These results were backed up by scanning electron microscopy studies demonstrating that exposure with cathelicidin LL-37 caused C. auris cells to undergo extensive surface changes. Spectrophotometric analysis revealed that cathelicidin LL-37 caused oxidative stress in C. auris, as is evident from the significant increase in the activity of primary antioxidant enzymes. In addition, cathelicidin LL-37 inhibited the cell cycle and accumulated cells in the S phase. Therefore, these results specify the potential of cathelicidin LL-37 for developing a new and effective anti-Candida agent.
Collapse
Affiliation(s)
- Irfan A. Rather
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah 21589, Saudi Arabia;
- Centre of Excellence in Bionanoscience Research, King Abdulaziz University (KAU), Jeddah 21589, Saudi Arabia
- Correspondence: (I.A.R.); (S.A.)
| | - Jamal S. M. Sabir
- Department of Biological Sciences, Faculty of Science, King Abdulaziz University (KAU), Jeddah 21589, Saudi Arabia;
- Centre of Excellence in Bionanoscience Research, King Abdulaziz University (KAU), Jeddah 21589, Saudi Arabia
| | - Amer H. Asseri
- Biochemistry Department, Faculty of Science, King Abdulaziz University (KAU), Jeddah 21589, Saudi Arabia;
| | - Sajad Ali
- Department of Biotechnology, Yeungnam University, Gyeongsan 385541, Korea
- Correspondence: (I.A.R.); (S.A.)
| |
Collapse
|
5
|
Olmeda-López H, Corral-Lugo A, McConnell MJ. Effect of Subinhibitory Concentrations of Antibiotics and Disinfectants on IS Aba-Mediated Inactivation of Lipooligosaccharide Biosynthesis Genes in Acinetobacter baumannii. Antibiotics (Basel) 2021; 10:antibiotics10101259. [PMID: 34680840 PMCID: PMC8532902 DOI: 10.3390/antibiotics10101259] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 01/03/2023] Open
Abstract
Inactivation of the lipooligosaccharide (LOS) biosynthesis genes lpxA, lpxC and lpxD by ISAba insertion elements results in high-level resistance to colistin in A. baumannii. In the present study, we quantify the rate of spontaneous insertional inactivation of LOS biosynthesis genes by ISAba elements in the ATCC 19606-type strain and two multidrug clinical isolates. Using insertional inactivation of lpxC by ISAba11 in the ATCC 19606 strain as a model, we determine the effect of several subinhibitory concentrations of the antibiotics, namely tetracycline, ciprofloxacin, meropenem, kanamycin and rifampicin, as well as the disinfectants ethanol and chlorhexidine on ISAba11 insertion frequencies. Notably, subinhibitory concentrations of tetracycline significantly increased ISAba11 insertion, and rifampicin completely inhibited the emergence of colistin resistance due to ISAba11 inactivation of lpxC. Sequencing of ISAba11 insertion sites within the lpxC gene demonstrated that insertions clustered between nucleotides 382 and 618 (58.3% of unique insertions detected), indicating that this may be a hotspot for ISAba11 insertion. The alignment of insertion sites revealed a semi-conserved AT-rich consensus sequence upstream of the ISAba11 insertion site, suggesting that ISAba11 insertion sites may be sequence-dependent. This study explores previously uncharacterized aspects regarding the acquisition of colistin resistance through insertional activation in LOS biosynthesis genes in A. baumannii.
Collapse
|
6
|
Ridyard KE, Overhage J. The Potential of Human Peptide LL-37 as an Antimicrobial and Anti-Biofilm Agent. Antibiotics (Basel) 2021; 10:antibiotics10060650. [PMID: 34072318 PMCID: PMC8227053 DOI: 10.3390/antibiotics10060650] [Citation(s) in RCA: 76] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 02/06/2023] Open
Abstract
The rise in antimicrobial resistant bacteria threatens the current methods utilized to treat bacterial infections. The development of novel therapeutic agents is crucial in avoiding a post-antibiotic era and the associated deaths from antibiotic resistant pathogens. The human antimicrobial peptide LL-37 has been considered as a potential alternative to conventional antibiotics as it displays broad spectrum antibacterial and anti-biofilm activities as well as immunomodulatory functions. While LL-37 has shown promising results, it has yet to receive regulatory approval as a peptide antibiotic. Despite the strong antimicrobial properties, LL-37 has several limitations including high cost, lower activity in physiological environments, susceptibility to proteolytic degradation, and high toxicity to human cells. This review will discuss the challenges associated with making LL-37 into a viable antibiotic treatment option, with a focus on antimicrobial resistance and cross-resistance as well as adaptive responses to sub-inhibitory concentrations of the peptide. The possible methods to overcome these challenges, including immobilization techniques, LL-37 delivery systems, the development of LL-37 derivatives, and synergistic combinations will also be considered. Herein, we describe how combination therapy and structural modifications to the sequence, helicity, hydrophobicity, charge, and configuration of LL-37 could optimize the antimicrobial and anti-biofilm activities of LL-37 for future clinical use.
Collapse
|
7
|
毛 洪, 何 明, 和 素. [Significance of Lipopolysaccharide Lipid A Gene Mutation of Extensively Drug-resistant Acinetobacter baumanii on Polymyxin Resistance and Its Influence on Treatment]. SICHUAN DA XUE XUE BAO. YI XUE BAN = JOURNAL OF SICHUAN UNIVERSITY. MEDICAL SCIENCE EDITION 2021; 52:124-128. [PMID: 33474901 PMCID: PMC10408946 DOI: 10.12182/20210160208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Indexed: 11/23/2022]
Abstract
OBJECTIVE To explore the significance of the resistance to polymyxin resistance of the extensively drug resistant Acinetobacter baumannii (XDRAB) lipopolysaccharide (LPS) lpx A, lpx C, lpx D and to screen appropriate combination therapy. METHODS In the past two years, 72 XDRAB in the secretions of our patients were selected as the research object. According to the minimum inhibitory concentration (MIC) of the XDRAB strain on polymyxin, they were included in the drug resistance group and the sensitive group. The gene sequences of strains lpx A, lpx C, lpx D were compared with the standard strains to analyze gene mutations and compared the mutation rates in the drug resistant group and the sensitive group. The efficacy of the combination drugs was evaluated by microcheckerboard dilution method, including polymyxin+imipenem group, polymyxin+meropenem group, polymyxin+cefoperazone/sulbactam group, polymyxin+levofloxacin group, and polymyxin+fosfomycin group. Calculated the fractional inhibitory concentration (FIC) index of the combined medication regimen and compared the percentage of strains that exhibited synergistic, additive, irrelevant, and antagonistic effects. RESULTS Tentyone were in the drug resistant group, accounting for 21 (29.17%,) and 51 were in the sensitive group, accounting for 70.83%. Some strains had mutations in lpx A, lpx C, lpx D genes. The mutation rate in the drug resistant group was 90.48%, which was significantly higher than 11.76% in the sensitive group, the difference was statistically significant ( P<0.05). The combined drug sensitivity test showed, compared with the polymyxin+fosfomycin group, the mycotin+fosfomycin group had a higher percentage of strains with synergistic FIC index in the polymyxin+imipenem group, the difference was statistically significant ( P<0.01). CONCLUSION XDRAB is resistant to polymyxin, which is related to mutations in LPS lipid A biosynthesis genes lpx A, lpx C, lpx D. Clinical treatment should adopt a combination of polymyxin+imipenem/meropenem and other drug combination to reduce the secondary infection of drug resistant bacteria.
Collapse
Affiliation(s)
- 洪宾 毛
- 开封市人民医院 临床药学科 (开封 475000)Department of Clinical Pharmacy, Kaifeng People’s Hospital, Kaifeng 475000, China
| | - 明 何
- 开封市人民医院 临床药学科 (开封 475000)Department of Clinical Pharmacy, Kaifeng People’s Hospital, Kaifeng 475000, China
| | - 素娜 和
- 开封市人民医院 临床药学科 (开封 475000)Department of Clinical Pharmacy, Kaifeng People’s Hospital, Kaifeng 475000, China
| |
Collapse
|
8
|
Monem S, Furmanek-Blaszk B, Łupkowska A, Kuczyńska-Wiśnik D, Stojowska-Swędrzyńska K, Laskowska E. Mechanisms Protecting Acinetobacter baumannii against Multiple Stresses Triggered by the Host Immune Response, Antibiotics and Outside-Host Environment. Int J Mol Sci 2020; 21:E5498. [PMID: 32752093 PMCID: PMC7432025 DOI: 10.3390/ijms21155498] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 02/06/2023] Open
Abstract
Acinetobacter baumannii is considered one of the most persistent pathogens responsible for nosocomial infections. Due to the emergence of multidrug resistant strains, as well as high morbidity and mortality caused by this pathogen, A. baumannii was placed on the World Health Organization (WHO) drug-resistant bacteria and antimicrobial resistance research priority list. This review summarizes current studies on mechanisms that protect A. baumannii against multiple stresses caused by the host immune response, outside host environment, and antibiotic treatment. We particularly focus on the ability of A. baumannii to survive long-term desiccation on abiotic surfaces and the population heterogeneity in A. baumannii biofilms. Insight into these protective mechanisms may provide clues for the development of new strategies to fight multidrug resistant strains of A. baumannii.
Collapse
Affiliation(s)
- Soroosh Monem
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Beata Furmanek-Blaszk
- Department of Microbiology, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland;
| | - Adrianna Łupkowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Dorota Kuczyńska-Wiśnik
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Karolina Stojowska-Swędrzyńska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| | - Ewa Laskowska
- Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308 Gdansk, Poland; (S.M.); (A.Ł.); (D.K.-W.); (K.S.-S.)
| |
Collapse
|
9
|
Kamoshida G, Akaji T, Takemoto N, Suzuki Y, Sato Y, Kai D, Hibino T, Yamaguchi D, Kikuchi-Ueda T, Nishida S, Unno Y, Tansho-Nagakawa S, Ubagai T, Miyoshi-Akiyama T, Oda M, Ono Y. Lipopolysaccharide-Deficient Acinetobacter baumannii Due to Colistin Resistance Is Killed by Neutrophil-Produced Lysozyme. Front Microbiol 2020; 11:573. [PMID: 32373082 PMCID: PMC7183746 DOI: 10.3389/fmicb.2020.00573] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 03/16/2020] [Indexed: 12/16/2022] Open
Abstract
Acinetobacter baumannii causes nosocomial infections due to its multidrug resistance and high environmental adaptability. Colistin is a polypeptide antibacterial agent that targets lipopolysaccharide (LPS) and is currently used to control serious multidrug-resistant Gram-negative bacterial infections, including those caused by A. baumannii. However, A. baumannii may acquire colistin resistance by losing their LPS. In mouse models, LPS-deficient A. baumannii have attenuated virulence. Nevertheless, the mechanism through which the pathogen is cleared by host immune cells is unknown. Here, we established colistin-resistant A. baumannii strains and analyzed possible mechanisms through which they are cleared by neutrophils. Colistin-resistant, LPS-deficient strains harbor mutations or insertion sequence (IS) in lpx genes, and introduction of intact lpx genes restored LPS deficiency. Analysis of interactions between these strains and neutrophils revealed that compared with wild type, LPS-deficient A. baumannii only weakly stimulated neutrophils, with consequent reduced levels of reactive oxygen species (ROS) and inflammatory cytokine production. Nonetheless, neutrophils preferentially killed LPS-deficient A. baumannii compared to wild-type strains. Moreover, LPS-deficient A. baumannii strains presented with increased sensitivities to antibacterial lysozyme and lactoferrin. We revealed that neutrophil-secreted lysozyme was the antimicrobial factor during clearance of LPS-deficient A. baumannii strains. These findings may inform the development of targeted therapeutics aimed to treat multidrug-resistant infections in immunocompromised patients who are unable to mount an appropriate cell-mediated immune response.
Collapse
Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan.,Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Takuya Akaji
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Norihiko Takemoto
- Pathogenic Microbe Laboratory, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Yusuke Suzuki
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Yoshinori Sato
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Daichi Kai
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Taishi Hibino
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Daiki Yamaguchi
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Takane Kikuchi-Ueda
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Satoshi Nishida
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Yuka Unno
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Shigeru Tansho-Nagakawa
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Tsuneyuki Ubagai
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| | - Tohru Miyoshi-Akiyama
- Pathogenic Microbe Laboratory, Department of Infectious Diseases, Research Institute, National Center for Global Health and Medicine, Tokyo, Japan
| | - Masataka Oda
- Department of Microbiology and Infection Control Sciences, Kyoto Pharmaceutical University, Kyoto, Japan
| | - Yasuo Ono
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
| |
Collapse
|
10
|
Rahnamoun A, Kim K, Pedersen JA, Hernandez R. Ionic Environment Affects Bacterial Lipopolysaccharide Packing and Function. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:3149-3158. [PMID: 32069057 DOI: 10.1021/acs.langmuir.9b03162] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The interaction of lipopolysaccharides (LPS) with metal cations strongly affects the stability and function of the Gram-negative bacterial outer membrane. The sensitivity of deep rough (Re) LPS packing and function to the ionic environment, as affected by cation valency and ionic radius, has been determined using molecular dynamics simulations and Langmuir balance experiments. The degree of LPS aggregation within the LPS models in the presence of different cations is assessed by measuring the effective mean molecular area (Âm) of each LPS molecule projected onto the interfacial plane at the end of the equilibration. These results are compared to the LPS mean molecular area from experimental measurements in which the LPS monolayers are assembled at the air-water interface using a Langmuir film balance. We found that packing of the LPS arrays is sensitive to the ionic radius and ion valency of the cations present in solution during LPS array packing. Using enhanced sampling of the free energy for the intercalation of oligo(allylamine HCl) (OAH) into deep rough Salmonella enterica LPS bilayers, we obtained the affinity of the core section of LPS to OAH as a function of the nature of the metal cations present in solution. We found that packing of the solvated LPS bilayer models is sensitive to ionic radius and ion valency of the neutralizing cations. This further suggests that ion bridging and steric barriers rather than charge shielding are important factors in mitigating ligand intercalation under conditions with low ionic concentrations.
Collapse
Affiliation(s)
- Ali Rahnamoun
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - Kyoungtea Kim
- Molecular and Environmental Toxicology Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Joel A Pedersen
- Molecular and Environmental Toxicology Program, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
- Departments of Soil Science, Chemistry, Civil & Environmental Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706, United States
| | - Rigoberto Hernandez
- Department of Chemistry, Johns Hopkins University, Baltimore, Maryland 21218, United States
| |
Collapse
|
11
|
Pulido MR, García-Quintanilla M, Pachón J, McConnell MJ. A lipopolysaccharide-free outer membrane vesicle vaccine protects against Acinetobacter baumannii infection. Vaccine 2019; 38:719-724. [PMID: 31843268 DOI: 10.1016/j.vaccine.2019.11.043] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Revised: 10/24/2019] [Accepted: 11/16/2019] [Indexed: 11/27/2022]
Abstract
Outer membrane vesicles (OMVs) were isolated from an Acinetobacter strain deficient in lipopolysaccharide (LPS) due to a mutation in lpxD (IB010). Two immunizations with 10 µg of IB010 OMVs elicited total IgG, IgM, IgG1 and IgG2c titers similar to those observed after immunization with OMVs derived from the parental strain (ATCC 19606), and IB010 OMVs plus purified LPS. Immunization with IB010 OMVs resulted in significantly reduced post-infection spleen bacterial loads and serum IL-1β and IL-6 levels compared to control mice in a disseminated sepsis model. Mice immunized with 10 µg IB010 OMVs demonstrated significant, but partial, protection (75%) against infection, whereas mice immunized with ATCC 19606 OMVs or IB010 OMVs plus purified LPS were completely protected. Immunization of mice with 100 µg of IB010 OMVs completely protected mice from infection. This study demonstrates that LPS deficient A. baumannii produces OMVs, and that immunization with these OMVs elicits protective immunity against infection.
Collapse
Affiliation(s)
- Marina R Pulido
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Meritxell García-Quintanilla
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain
| | - Jerónimo Pachón
- Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, Seville, Spain; Department of Medicine, University of Seville, Seville, Spain
| | - Michael J McConnell
- National Centre for Microbiology, Instituto de Salud Carlos III, Madrid, Spain.
| |
Collapse
|
12
|
Al-Farsi HM, Al-Adwani S, Ahmed S, Vogt C, Ambikan AT, Leber A, Al-Jardani A, Al-Azri S, Al-Muharmi Z, Toprak MS, Giske CG, Bergman P. Effects of the Antimicrobial Peptide LL-37 and Innate Effector Mechanisms in Colistin-Resistant Klebsiella pneumoniae With mgrB Insertions. Front Microbiol 2019; 10:2632. [PMID: 31803163 PMCID: PMC6870453 DOI: 10.3389/fmicb.2019.02632] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 10/29/2019] [Indexed: 11/14/2022] Open
Abstract
Background Colistin is a polypeptide antibiotic drug that targets lipopolysaccharides in the outer membrane of Gram-negative bacteria. Inactivation of the mgrB-gene is a common mechanism behind colistin-resistance in Klebsiella pneumoniae (Kpn). Since colistin is a cyclic polypeptide, it may exhibit cross-resistance with the antimicrobial peptide LL-37, and with other innate effector mechanisms, but previous results are inconclusive. Objective To study potential cross-resistance between colistin and LL-37, as well as with other innate effector mechanisms, and to compare virulence of colistin-resistant and susceptible Kpn strains. Materials/Methods Carbapenemase-producing Kpn from Oman (n = 17) were subjected to antimicrobial susceptibility testing and whole genome sequencing. Susceptibility to colistin and LL-37 was studied. The surface charge was determined by zeta-potential measurements and the morphology of treated bacteria was analyzed with electron microscopy. Bacterial survival was assessed in human whole blood and serum, as well as in a zebrafish infection-model. Results Genome-analysis revealed insertion-sequences in the mgrB gene, as a cause of colistin resistance in 8/17 isolates. Colistin-resistant (Col-R) isolates were found to be more resistant to LL-37 compared to colistin-susceptible (Col-S) isolates, but only at concentrations ≥50 μg/ml. There was no significant difference in surface charge between the isolates. The morphological changes were similar in both Col-R and Col-S isolates after exposure to LL-37. Finally, no survival difference between the Col-R and Col-S isolates was observed in whole blood or serum, or in zebrafish embryos. Conclusion Cross-resistance between colistin and LL-37 was observed at elevated concentrations of LL-37. However, Col-R and Col-S isolates exhibited similar survival in serum and whole blood, and in a zebrafish infection-model, suggesting that cross-resistance most likely play a limited role during physiological conditions. However, it cannot be ruled out that the observed cross-resistance could be relevant in conditions where LL-37 levels reach high concentrations, such as during infection or inflammation.
Collapse
Affiliation(s)
- Hissa M Al-Farsi
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.,Central Public Health Laboratories, Ministry of Health, Muscat, Oman
| | - Salma Al-Adwani
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.,Department of Animal and Veterinary Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
| | - Sultan Ahmed
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden
| | - Carmen Vogt
- Department of Applied Physics, Biomedical and X-Ray Physics, KTH Royal Institute of Technology/AlbaNova, Stockholm, Sweden
| | - Anoop T Ambikan
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden
| | - Anna Leber
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden
| | - Amina Al-Jardani
- Central Public Health Laboratories, Ministry of Health, Muscat, Oman
| | - Saleh Al-Azri
- Central Public Health Laboratories, Ministry of Health, Muscat, Oman
| | - Zakariya Al-Muharmi
- Department of Microbiology & Immunology, College of Medicine & Health Sciences, Sultan Qaboos University, Muscat, Oman
| | - Muhammet S Toprak
- Department of Applied Physics, Biomedical and X-Ray Physics, KTH Royal Institute of Technology/AlbaNova, Stockholm, Sweden
| | - Christian G Giske
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
| | - Peter Bergman
- Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska Institutet, Stockholm, Sweden.,Infectious Disease Clinic, The Immunodeficiency Unit, Karolinska University Hospital, Stockholm, Sweden
| |
Collapse
|
13
|
Geisinger E, Huo W, Hernandez-Bird J, Isberg RR. Acinetobacter baumannii: Envelope Determinants That Control Drug Resistance, Virulence, and Surface Variability. Annu Rev Microbiol 2019; 73:481-506. [DOI: 10.1146/annurev-micro-020518-115714] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Acinetobacter baumannii has emerged as an important nosocomial pathogen, particularly for patients in intensive care units and with invasive indwelling devices. The most recent clinical isolates are resistant to several classes of clinically important antibiotics, greatly restricting the ability to effectively treat critically ill patients. The bacterial envelope is an important driver of A. baumannii disease, both at the level of battling against antibiotic therapy and at the level of protecting from host innate immune function. This review provides a comprehensive overview of key features of the envelope that interface with both the host and antimicrobial therapies. Carbohydrate structures that contribute to protecting from the host are detailed, and mutations that alter these structures, resulting in increased antimicrobial resistance, are explored. In addition, protein complexes involved in both intermicrobial and host-microbe interactions are described. Finally we discuss regulatory mechanisms that control the nature of the cell envelope and its impact on host innate immune function.
Collapse
Affiliation(s)
- Edward Geisinger
- Department of Biology, Northeastern University, Boston, Massachusetts 02115, USA
| | - Wenwen Huo
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
| | - Juan Hernandez-Bird
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
| | - Ralph R. Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
| |
Collapse
|
14
|
Luo Q, Niu T, Wang Y, Yin J, Wan F, Yao M, Lu H, Xiao Y, Li L. In vitro reduction of colistin susceptibility and comparative genomics reveals multiple differences between MCR-positive and MCR-negative colistin-resistant Escherichia coli. Infect Drug Resist 2019; 12:1665-1674. [PMID: 31354315 PMCID: PMC6580138 DOI: 10.2147/idr.s210245] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 05/13/2019] [Indexed: 11/23/2022] Open
Abstract
Objectives: Although resistance to colistin is increasingly reported from clinical settings, the genetic mechanisms that lead to colistin resistance in Escherichia coli have not been fully characterized. Here, we assess the evolution of colistin resistance in clinical isolates of mobilized colistin resistance (MCR)-negative and MCR-positive Escherichia coli. Methods: Spontaneously mutated colistin-resistant progeny were evolved using a step-wise reduction of colistin susceptibility. Resistance phenotypes were confirmed by minimum inhibitory concentration (MIC) determination, and the probable resistance mechanisms were investigated using PCR and reverse transcription-quantitative PCR. Mutated genes of the laboratory-evolved mutants were identified by whole-genome sequencing and comparative genomics. Fitness costs and serum resistance of the mutants were also compared to the corresponding wild types. Results: MCR-negative isolates displayed higher increases in MICs than did MCR-positive isolates following colistin exposure. Upregulation of pmrAB and associated genes was evident among MCR-negative isolates but not MCR-positive isolates. Comparative genomic analysis of mutants and their corresponding wild-types (WTs) revealed numerous mutations in genes encoding membrane transporters and two-component systems. Additionally, MCR-negative mutants exhibited higher fitness costs than MCR-positive mutants compared with their corresponding WTs but displayed similar serum resistance. Conclusion: Our findings reveal multiple differences between MCR-positive and MCR-negative E. coli strains following colistin exposure, which provide reference values for clinical medication.
Collapse
Affiliation(s)
- Qixia Luo
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases , Hangzhou, The First Affiliated Hospital, College of Medicine, Zhejiang University, People's Republic of China
| | - Tianshui Niu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases , Hangzhou, The First Affiliated Hospital, College of Medicine, Zhejiang University, People's Republic of China
| | - Yuan Wang
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases , Hangzhou, The First Affiliated Hospital, College of Medicine, Zhejiang University, People's Republic of China
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, People's Republic of China
| | - Fen Wan
- College of Laboratory Medicine, Hangzhou Medical College, Hangzhou, People's Republic of China
| | - Mingfei Yao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases , Hangzhou, The First Affiliated Hospital, College of Medicine, Zhejiang University, People's Republic of China
| | - Haifeng Lu
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases , Hangzhou, The First Affiliated Hospital, College of Medicine, Zhejiang University, People's Republic of China
| | - Yonghong Xiao
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases , Hangzhou, The First Affiliated Hospital, College of Medicine, Zhejiang University, People's Republic of China
| | - Lanjuan Li
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases , Hangzhou, The First Affiliated Hospital, College of Medicine, Zhejiang University, People's Republic of China
| |
Collapse
|
15
|
Brunati C, Thomsen TT, Gaspari E, Maffioli S, Sosio M, Jabes D, Løbner-Olesen A, Donadio S. Expanding the potential of NAI-107 for treating serious ESKAPE pathogens: synergistic combinations against Gram-negatives and bactericidal activity against non-dividing cells. J Antimicrob Chemother 2019; 73:414-424. [PMID: 29092042 PMCID: PMC5890740 DOI: 10.1093/jac/dkx395] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 09/27/2017] [Indexed: 11/12/2022] Open
Abstract
Objectives To characterize NAI-107 and related lantibiotics for their in vitro activity against Gram-negative pathogens, alone or in combination with polymyxin, and against non-dividing cells or biofilms of Staphylococcus aureus. NAI-107 was also evaluated for its propensity to select or induce self-resistance in Gram-positive bacteria. Methods We used MIC determinations and chequerboard experiments to establish the antibacterial activity of the examined compounds against target microorganisms. Time-kill assays were used to evaluate killing of exponential and stationary-phase cells. The effects on biofilms (growth inhibition and biofilm eradication) were evaluated using biofilm-coated pegs. The frequency of spontaneous resistant mutants was evaluated by either direct plating or by continuous sub-culturing at 0.5 × MIC levels, followed by population analysis profiles. Results The results showed that NAI-107 and its brominated variant are highly active against Neisseria gonorrhoeae and some other fastidious Gram-negative pathogens. Furthermore, all compounds strongly synergized with polymyxin against Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa, and showed bactericidal activity. Surprisingly, NAI-107 alone was bactericidal against non-dividing A. baumannii cells. Against S. aureus, NAI-107 and related lantibiotics showed strong bactericidal activity against dividing and non-dividing cells. Activity was also observed against S. aureus biofilms. As expected for a lipid II binder, no significant resistance to NAI-107 was observed by direct plating or serial passages. Conclusions Overall, the results of the current work, along with previously published results on the efficacy of NAI-107 in experimental models of infection, indicate that this lantibiotic represents a promising option in addressing the serious threat of antibiotic resistance.
Collapse
Affiliation(s)
- Cristina Brunati
- NAICONS Srl, Viale Ortles 22/4, 20139 Milano, Italy.,KtedoGen Srl, Viale Ortles 22/4, 20139 Milano, Italy
| | - Thomas T Thomsen
- Department of Biology, University of Copenhagen, Ole Maaløe's Vej 5, 2200 Copenhagen, Denmark
| | | | | | - Margherita Sosio
- NAICONS Srl, Viale Ortles 22/4, 20139 Milano, Italy.,KtedoGen Srl, Viale Ortles 22/4, 20139 Milano, Italy
| | | | - Anders Løbner-Olesen
- Department of Biology, University of Copenhagen, Ole Maaløe's Vej 5, 2200 Copenhagen, Denmark
| | - Stefano Donadio
- NAICONS Srl, Viale Ortles 22/4, 20139 Milano, Italy.,KtedoGen Srl, Viale Ortles 22/4, 20139 Milano, Italy
| |
Collapse
|
16
|
Carretero-Ledesma M, García-Quintanilla M, Martín-Peña R, Pulido MR, Pachón J, McConnell MJ. Phenotypic changes associated with Colistin resistance due to Lipopolysaccharide loss in Acinetobacter baumannii. Virulence 2018; 9:930-942. [PMID: 29638177 PMCID: PMC5955468 DOI: 10.1080/21505594.2018.1460187] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Acinetobacter baumannii can acquire resistance to colistin via complete loss of lipopolysaccharide (LPS) biosynthesis due to mutations in the lpxA, lpxC and lpxD genes. However, although colistin is increasingly being used for the treatment of multidrug resistant infections, very few A. baumannii clinical isolates develop colistin resistance through loss of LPS biosynthesis. This may suggest that LPS loss affects virulence traits that play a role in the transmission and pathogenesis of A. baumannii. In this study we characterize multiple virulence phenotypes of colistin resistant, LPS-deficient derivatives of the ATCC 19606 strain and five multidrug resistant clinical isolates and their colistin resistant, LPS-deficient derivatives. Our results indicate that LPS loss results in growth defects compared to the parental strain in vitro both in laboratory media and human serum (competition indices of 0.58 and 7.0 × 10−7, respectively) and reduced ability to grow and disseminate in vivo (competition index 6.7 × 10−8). Infection with the LPS-deficient strain resulted in lower serum levels of pro-inflammatory cytokines TNF-α and IL-6 compared to the parent strain, and was less virulent in a mouse model of disseminated sepsis. LPS loss also significantly affected biofilm production, surface motility, growth under iron limitation and susceptibility to multiple disinfectants used in the clinical setting. These results demonstrate that LPS loss has a significant effect on multiple virulence traits, and may provide insight into the low incidence of colistin resistant strains lacking LPS that have been reported in the clinical setting.
Collapse
Affiliation(s)
- Marta Carretero-Ledesma
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| | - Meritxell García-Quintanilla
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| | - Reyes Martín-Peña
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| | - Marina R Pulido
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| | - Jerónimo Pachón
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain.,b Department of Medicine , University of Seville , Seville , Spain
| | - Michael J McConnell
- a Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine; Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC /University of Seville , Seville , Spain
| |
Collapse
|
17
|
Pulido MR, García-Quintanilla M, Pachón J, McConnell MJ. Immunization with lipopolysaccharide-free outer membrane complexes protects against Acinetobacter baumannii infection. Vaccine 2018; 36:4153-4156. [PMID: 29887323 DOI: 10.1016/j.vaccine.2018.05.113] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 05/29/2018] [Accepted: 05/31/2018] [Indexed: 12/27/2022]
Abstract
Outer membrane complex (OMC) vaccines, which contain antigens from the bacterial outer membrane, have been developed for multiple Gram-negative bacteria. However, OMC vaccines demonstrate high endotoxin activity due to the presence of lipopolysaccharide in the bacterial outer membrane, thus precluding their use in humans. We isolated OMCs from an LPS-deficient strain of A. baumannii (IB010) which completely lacks LPS due to a mutation in the lpxD gene. OMCs from IB010 demonstrated a more than 10,000-fold reduction in endotoxin activity compared to OMCs from wild type A. baumannii. Vaccination with IB010 OMCs produced similar levels of antigen-specific IgG and IgM after two administrations compared to wild type OMCs, and resulted in a similar reduction in post-infection spleen bacterial loads and serum pro-inflammatory cytokine levels. Vaccination with IB010 OMCs provided significant protection against infection compared to control mice, indicating the LPS-free OMCs could contribute to vaccine strategies for preventing infection by A. baumannii.
Collapse
Affiliation(s)
- Marina R Pulido
- Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain
| | - Meritxell García-Quintanilla
- Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain
| | - Jerónimo Pachón
- Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain; Department of Medicine, University of Seville, Seville, Spain.
| | - Michael J McConnell
- Clinical Unit of Infectious Diseases, Clinical Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville, 41013 Seville, Spain.
| |
Collapse
|
18
|
Defraine V, Liebens V, Loos E, Swings T, Weytjens B, Fierro C, Marchal K, Sharkey L, O'Neill AJ, Corbau R, Marchand A, Chaltin P, Fauvart M, Michiels J. 1-((2,4-Dichlorophenethyl)Amino)-3-Phenoxypropan-2-ol Kills Pseudomonas aeruginosa through Extensive Membrane Damage. Front Microbiol 2018; 9:129. [PMID: 29472905 PMCID: PMC5809444 DOI: 10.3389/fmicb.2018.00129] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/18/2018] [Indexed: 12/31/2022] Open
Abstract
The ever increasing multidrug-resistance of clinically important pathogens and the lack of novel antibiotics have resulted in a true antibiotic crisis where many antibiotics are no longer effective. Further complicating the treatment of bacterial infections are antibiotic-tolerant persister cells. Besides being responsible for the recalcitrant nature of chronic infections, persister cells greatly contribute to the observed antibiotic tolerance in biofilms and even facilitate the emergence of antibiotic resistance. Evidently, eradication of these persister cells could greatly improve patient outcomes and targeting persistence may provide an alternative approach in combatting chronic infections. We recently characterized 1-((2,4-dichlorophenethyl)amino)-3-phenoxypropan-2-ol (SPI009), a novel anti-persister molecule capable of directly killing persisters from both Gram-negative and Gram-positive pathogens. SPI009 potentiates antibiotic activity in several in vitro and in vivo infection models and possesses promising anti-biofilm activity. Strikingly, SPI009 restores antibiotic sensitivity even in resistant strains. In this study, we investigated the mode of action of this novel compound using several parallel approaches. Genetic analyses and a macromolecular synthesis assays suggest that SPI009 acts by causing extensive membrane damage. This hypothesis was confirmed by liposome leakage assay and membrane permeability studies, demonstrating that SPI009 rapidly impairs the bacterial outer and inner membranes. Evaluation of SPI009-resistant mutants, which only could be generated under severe selection pressure, suggested a possible role for the MexCD-OprJ efflux pump. Overall, our results demonstrate the extensive membrane-damaging activity of SPI009 and confirm its clinical potential in the development of novel anti-persister therapies.
Collapse
Affiliation(s)
- Valerie Defraine
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,Center for Microbiology, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
| | - Veerle Liebens
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Evelien Loos
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Toon Swings
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,Center for Microbiology, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
| | - Bram Weytjens
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Carolina Fierro
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
| | - Kathleen Marchal
- Data Integration and Biological Networks, Ghent University, Ghent, Belgium
| | - Liam Sharkey
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | - Alex J O'Neill
- School of Molecular and Cellular Biology, University of Leeds, Leeds, United Kingdom
| | | | | | - Patrick Chaltin
- CISTIM Leuven vzw, Leuven, Belgium.,Centre for Drug Design and Discovery, Leuven, Belgium
| | - Maarten Fauvart
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,Smart Electronics Unit, Department of Life Sciences and Imaging, imec, Leuven, Belgium
| | - Jan Michiels
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium.,Center for Microbiology, Vlaams Instituut voor Biotechnologie, Leuven, Belgium
| |
Collapse
|
19
|
Lee H, Roh KH, Hong SG, Shin HB, Jeong SH, Song W, Uh Y, Yong D, Lee K. In Vitro Synergistic Effects of Antimicrobial Combinations on Extensively Drug-Resistant Pseudomonas aeruginosa and Acinetobacter baumannii Isolates. Ann Lab Med 2017; 36:138-44. [PMID: 26709261 PMCID: PMC4713847 DOI: 10.3343/alm.2016.36.2.138] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/13/2015] [Accepted: 12/02/2015] [Indexed: 01/30/2023] Open
Abstract
Background Extensively drug-resistant (XDR) Pseudomonas aeruginosa and Acinetobacter baumannii are a threat to hospitalized patients. We evaluated the effects of antimicrobial combinations on XDR P. aeruginosa and A. baumannii isolates. Methods P. aeruginosa and A. baumannii isolates, which were resistant to all antibiotics except colistin (CL), were collected from eight hospitals in Korea. Genes encoding metallo-β-lactamases (MBLs) and OXA carbapenemases were detected by PCR in eight P. aeruginosa and 30 A. baumannii isolates. In vitro synergy of antimicrobial combinations was tested by using the checkerboard method. Results Minimum inhibitory concentrations of β-lactams, aminoglycosides, and fluoroquinolones were very high, while that of CL was low for majority of XDR P. aeruginosa and A. baumannii isolates. Antimicrobial combinations including Imipenem (IPM)-CL, ceftazidime (CAZ)-CL, and rifampin (RIF)-CL exerted only additive/indifferent effects on majority of XDR P. aeruginosa isolates. Proportions of XDR A. baumannii isolates that showed synergistic and additive/indifferent inhibition after treatment with antimicrobial combinations used are as follows: IPM-ampicillin-sulbactam (AMS), 17% and 80% isolates, respectively; IPM-rifampin (RIF), 13% and 81% isolates, respectively; IPM-CL, 13% and 87% isolates, respectively; and RIF-COL, 20% and 73% isolates, respectively. Significant proportion (19%) of XDR P. aeruginosa isolates produced MBLs, and majority (82%) of A. baumannii isolates produced either MBLs or OXA-23. Conclusions Our results suggest that combinations of IPM-AMS, IPM-RIF, IPM-CL, and RIF-CL are more useful than individual drugs for treating 13-20% of XDR A. baumannii infections.
Collapse
Affiliation(s)
- Hyukmin Lee
- Department of Laboratory Medicine, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea
| | - Kyung Ho Roh
- Seegene Institute of Life Sciences, Seoul, Korea
| | - Seong Geun Hong
- Department of Laboratory Medicine, Bundang CHA Hospital, Pochon CHA University College of Medicine, Seongnam, Korea
| | - Hee Bong Shin
- Department of Laboratory Medicine, Soonchunhyang Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea
| | - Seok Hoon Jeong
- Department of Laboratory Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Wonkeun Song
- Department of Laboratory Medicine, Gangnam Sacred Hospital, Hallym University College of Medicine, Seoul, Korea
| | - Young Uh
- Department of Laboratory Medicine, Wonju Severance Christian Hospital, Yonsei University, Wonju College of Medicine, Wonju, Korea
| | - Dongeun Yong
- Department of Laboratory Medicine, Severance Hospital Yonsei University College of Medicine, Seoul, Korea
| | - Kyungwon Lee
- Department of Laboratory Medicine, Severance Hospital Yonsei University College of Medicine, Seoul, Korea.
| |
Collapse
|
20
|
Inhibition of LpxC Increases Antibiotic Susceptibility in Acinetobacter baumannii. Antimicrob Agents Chemother 2016; 60:5076-9. [PMID: 27270288 DOI: 10.1128/aac.00407-16] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 06/02/2016] [Indexed: 02/02/2023] Open
Abstract
LpxC inhibitors have generally shown poor in vitro activity against Acinetobacter baumannii We show that the LpxC inhibitor PF-5081090 inhibits lipid A biosynthesis, as determined by silver staining and measurements of endotoxin levels, and significantly increases cell permeability. The presence of PF-5081090 at 32 mg/liter increased susceptibility to rifampin, vancomycin, azithromycin, imipenem, and amikacin but had no effect on susceptibility to ciprofloxacin and tigecycline. Potentiating existing antibiotics with LpxC inhibitors may represent an alternative treatment strategy for multidrug-resistant A. baumannii.
Collapse
|
21
|
Xiao SZ, Chu HQ, Han LZ, Zhang ZM, Li B, Zhao L, Xu L. Resistant mechanisms and molecular epidemiology of imipenem-resistant Acinetobacter baumannii. Mol Med Rep 2016; 14:2483-8. [PMID: 27485638 PMCID: PMC4991767 DOI: 10.3892/mmr.2016.5538] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Accepted: 07/22/2016] [Indexed: 11/05/2022] Open
Abstract
The aim of the study was to investigate the resistant mechanisms and homology of imipenem-resistant Acinetobacter baumannii (A. baumannii). A total of 46 non-duplicate imipenem‑resistant A. baumannii clinical isolates were collected from three tertiary hospitals between July, 2011 and June, 2012. The minimal inhibitory concentrations (MICs) of antimicrobial agents were determined using the agar dilution method. Phenylalanine‑arginine β-naphthylamide was used to detect the presence of the efflux pump-mediated resistant mechanism. Polymerase chain reaction was employed to amplify genes associated with drug resistance, including β‑lactamase genes, efflux pump genes and outer membrane protein gene CarO. A few amplicons were randomly selected and sequenced. Multilocus sequence analysis (MLST) was employed in typing A. baumanni. A. baumannii was resistant to imipenem, simultaneously showing resistance to several other antimicrobials. In addtition, 13 A. baumannii were found to mediate drug resistance through operation of the efflux pump. Of the various drug resistance genes tested, blaOXA‑51 was present in 46 isolates, blaOXA‑23 gene was present in 44 isolates and blaNDM gene was found in only one strain. Other drug resistant‑associated genes, including blaKPC, blaIMP, blaOXA-24, blaOXA‑58, blaSHV, blaGIM and blaVIM were not detected. Mutation of adeS and outer membrane protein gene CarO were found in a few of the imipenem‑resistant isolates. The MLST analysis revealed that all 46 clinical isolates were clustered into 11 genotypes and the most frequent genotype was ST208. In conclusion, β‑lactamase genes, genes involved in efflux pump and mutation of outer membrane protein encoding gene may be important in mediating imipenem resistance in A. baumannii. Of the 11 different genotypes, ST11 was shared by the majority of A. baumannii, which may be due to horizontal transfer of patients from hospitals.
Collapse
Affiliation(s)
- Shu-Zhen Xiao
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
| | - Hai-Qing Chu
- Department of Respiratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, P.R. China
| | - Li-Zhong Han
- Department of Clinical Microbiology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200025, P.R. China
| | - Zhe-Min Zhang
- Department of Respiratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, P.R. China
| | - Bing Li
- Department of Respiratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, P.R. China
| | - Lan Zhao
- Department of Respiratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, P.R. China
| | - Liyun Xu
- Department of Respiratory Medicine, Shanghai Pulmonary Hospital, Tongji University School of Medicine, Shanghai 200433, P.R. China
| |
Collapse
|
22
|
Candidacidal Activity of Selected Ceragenins and Human Cathelicidin LL-37 in Experimental Settings Mimicking Infection Sites. PLoS One 2016; 11:e0157242. [PMID: 27315208 PMCID: PMC4912103 DOI: 10.1371/journal.pone.0157242] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 05/26/2016] [Indexed: 12/31/2022] Open
Abstract
Fungal infections, especially those caused by antibiotic resistant pathogens, have become a serious public health problem due to the growing number of immunocompromised patients, including those subjected to anticancer treatment or suffering from HIV infection. In this study we assessed fungicidal activity of the ceragenins CSA-13, CSA-131 and CSA-192 against four fluconazole–resistant Candida strains. We found that ceragenins activity against planktonic Candida cells was higher than activity of human LL-37 peptide and synthetic cationic peptide omiganan. Compared to LL-37 peptide, ceragenins in the presence of DNase I demonstrated an increased ability to kill DNA-induced Candida biofilm. Microscopy studies show that treatment with LL-37 or ceragenins causes Candida cells to undergo extensive surface changes indicating surface membrane damage. This conclusion was substantiated by observation of rapid incorporation of FITC-labeled CSA-13, CSA-131 or LL-37 peptide into the more lipophilic environment of the Candida membrane. In addition to activity against Candida spp., ceragenins CSA-131 and CSA-192 display strong fungicidal activity against sixteen clinical isolates including Cryptococcus neoformans and Aspergillus fumigatus. These results indicate the potential of ceragenins for future development as new fungicidal agents.
Collapse
|
23
|
|
24
|
Smani Y, Pachón-Ibáñez ME, Pachón J. New molecules and adjuvants in the treatment of infections by Acinetobacter baumannii. Expert Opin Pharmacother 2016; 17:1207-14. [PMID: 27067283 DOI: 10.1080/14656566.2016.1176144] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
INTRODUCTION The current problems of the treatment of infections by Acinetobacter baumannii are linked with the increase of multidrug- and extensive-drug resistance and the lack of development of new antimicrobial drugs for Gram-negative bacilli. For these reasons, new alternatives for the treatment and control of severe infections by A. baumannii are necessary. Several studies have reported the effect of adjuvants to restore the efficacy of existing antimicrobial agents. AREAS COVERED In the present review, the authors describe the main results in the development of adjuvant drugs as well as new data on antimicrobial peptides, in monotherapy or in combination therapy with existing antimicrobial agents, which have shown promising preclinical results in vitro and in vivo. EXPERT OPINION The preclinical evaluation of adjuvants and antimicrobial peptides, in monotherapy or in combination therapy, for A. baumannii infections has shown promising results. However, caution is needed and further extensive in vivo studies and clinical trials have to be performed to confirm the potential use of these adjuvants as true therapeutic alternatives.
Collapse
Affiliation(s)
- Younes Smani
- a Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine , Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville , Seville , Spain
| | - María Eugenia Pachón-Ibáñez
- a Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine , Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville , Seville , Spain
| | - Jerónimo Pachón
- a Clinical Unit of Infectious Diseases, Microbiology, and Preventive Medicine , Institute of Biomedicine of Seville (IBiS), University Hospital Virgen del Rocío/CSIC/University of Seville , Seville , Spain
| |
Collapse
|
25
|
Tanphaichitr N, Srakaew N, Alonzi R, Kiattiburut W, Kongmanas K, Zhi R, Li W, Baker M, Wang G, Hickling D. Potential Use of Antimicrobial Peptides as Vaginal Spermicides/Microbicides. Pharmaceuticals (Basel) 2016; 9:E13. [PMID: 26978373 PMCID: PMC4812377 DOI: 10.3390/ph9010013] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 12/11/2022] Open
Abstract
The concurrent increases in global population and sexually transmitted infection (STI) demand a search for agents with dual spermicidal and microbicidal properties for topical vaginal application. Previous attempts to develop the surfactant spermicide, nonoxynol-9 (N-9), into a vaginal microbicide were unsuccessful largely due to its inefficiency to kill microbes. Furthermore, N-9 causes damage to the vaginal epithelium, thus accelerating microbes to enter the women's body. For this reason, antimicrobial peptides (AMPs), naturally secreted by all forms of life as part of innate immunity, deserve evaluation for their potential spermicidal effects. To date, twelve spermicidal AMPs have been described including LL-37, magainin 2 and nisin A. Human cathelicidin LL-37 is the most promising spermicidal AMP to be further developed for vaginal use for the following reasons. First, it is a human AMP naturally produced in the vagina after intercourse. Second, LL-37 exerts microbicidal effects to numerous microbes including those that cause STI. Third, its cytotoxicity is selective to sperm and not to the female reproductive tract. Furthermore, the spermicidal effects of LL-37 have been demonstrated in vivo in mice. Therefore, the availability of LL-37 as a vaginal spermicide/microbicide will empower women for self-protection against unwanted pregnancies and STI.
Collapse
Affiliation(s)
- Nongnuj Tanphaichitr
- Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6, ON, Canada.
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8L6, ON, Canada.
- Department of Biochemistry, Microbiology, Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, ON, Canada.
| | - Nopparat Srakaew
- Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6, ON, Canada.
- Department of Zoology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand.
| | - Rhea Alonzi
- Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6, ON, Canada.
- Department of Biochemistry, Microbiology, Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, ON, Canada.
| | - Wongsakorn Kiattiburut
- Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6, ON, Canada.
| | - Kessiri Kongmanas
- Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6, ON, Canada.
- Division of Dengue Hemorrhagic Fever Research Unit, Office of Research and Development, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand.
| | - Ruina Zhi
- Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6, ON, Canada.
- Key Laboratory of Reproduction Regulation of NPFPC, Shanghai Institute of Planned Parenthood Research, and School of Public Health, Fudan University, Shanghai 200032, China.
| | - Weihua Li
- Key Laboratory of Reproduction Regulation of NPFPC, Shanghai Institute of Planned Parenthood Research, and School of Public Health, Fudan University, Shanghai 200032, China.
| | - Mark Baker
- Reproductive Proteomics, Department of Science and Information technology, University of Newcastle, Callaghan Drive, Newcastle, NSW 2308 Australia.
| | - Guanshun Wang
- Department of Pathology and Microbiology, College of Medicine, University of Nebraska Medical Center, 986495 Nebraska Medical Center, Omaha, NE 68198-6495, USA.
| | - Duane Hickling
- Chronic Disease Program, Ottawa Hospital Research Institute, Ottawa, Ontario K1H 8L6, ON, Canada.
- Division of Urology, Department of Surgery, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1Y 4E9, ON, Canada.
| |
Collapse
|
26
|
Acinetobacter baumannii Infection and IL-17 Mediated Immunity. Mediators Inflamm 2016; 2016:9834020. [PMID: 26977122 PMCID: PMC4762998 DOI: 10.1155/2016/9834020] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 01/11/2016] [Indexed: 01/25/2023] Open
Abstract
Acinetobacter baumannii is a significant cause of severe hospital-acquired infections with a recent rise in multidrug-resistant infections involving traumatic wounds of military personnel. The interleukin-17 (IL-17) pathway is essential for neutrophil recruitment in response to a variety of pathogens, while the control of A. baumannii infection is known to be dependent on neutrophils. This suggests that IL-17 may play an important role in A. baumannii infection; however, this has yet to be studied. Here, we summarize the recent advances in understanding the host-pathogen interaction of A. baumannii and propose a potential role of the IL-17 pathway in generating a protective immune response.
Collapse
|
27
|
An Amphipathic Undecapeptide with All d-Amino Acids Shows Promising Activity against Colistin-Resistant Strains of Acinetobacter baumannii and a Dual Mode of Action. Antimicrob Agents Chemother 2015; 60:592-9. [PMID: 26574005 DOI: 10.1128/aac.01966-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 11/08/2015] [Indexed: 11/20/2022] Open
Abstract
Multiple strains of Acinetobacter baumannii have developed multidrug resistance (MDR), leaving colistin as the only effective treatment. The cecropin-α-melittin hybrid BP100 (KKLFKKILKYL-NH2) and its analogs have previously shown activity against a wide array of plant and human pathogens. In this study, we investigated the in vitro antibacterial activities of 18 BP100 analogs (four known and 14 new) against the MDR A. baumannii strain ATCC BAA-1605, as well as against a number of other clinically relevant human pathogens. Selected peptides were further evaluated against strains of A. baumannii that acquired resistance to colistin due to mutations of the lpxC, lpxD, pmrA, and pmrB genes. The novel analogue BP214 showed antimicrobial activity at 1 to 2 μM and a hemolytic 50% effective concentration (EC50) of >150 μM. The lower activity of its enantiomer suggests a dual, specific and nonspecific mode of action. Interestingly, colistin behaved antagonistically to BP214 when pmrAB and lpxC mutants were challenged.
Collapse
|
28
|
Lipopolysaccharide loss produces partial colistin dependence and collateral sensitivity to azithromycin, rifampicin and vancomycin in Acinetobacter baumannii. Int J Antimicrob Agents 2015; 46:696-702. [PMID: 26391380 DOI: 10.1016/j.ijantimicag.2015.07.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 07/29/2015] [Accepted: 07/29/2015] [Indexed: 12/11/2022]
Abstract
Treatment options for multidrug-resistant (MDR) strains of Acinetobacter baumannii that acquire resistance to colistin are limited. Acinetobacter baumannii can become highly resistant to colistin through complete loss of lipopolysaccharide (LPS) owing to mutations in the genes encoding the first three enzymes involved in lipid A biosynthesis (lpxA, lpxC and lpxD). The objective of this study was to characterise the susceptibility to 15 clinically relevant antibiotics and 6 antimicrobial peptides (AMPs) of MDR A. baumannii clinical isolates that acquired colistin resistance due to mutations in lpxA, lpxC and lpxD as well as their colistin-susceptible counterparts. A dramatic increase in antibiotic susceptibility (≥16-fold increase) was observed upon LPS loss for azithromycin, rifampicin and vancomycin, whereas a moderate increase in susceptibility was seen for amikacin, ceftazidime, imipenem, cefepime and meropenem. Importantly, concentrations ranging from 8 mg/L to 32 mg/L of the six AMPs were able to reduce bacterial viability by ≥3 log10 in growth curve assays. We also demonstrate that colistin resistance results in partial colistin dependence for growth in LPS-deficient strains containing mutations in lpxA, lpxC and lpxD, but not when colistin resistance occurs via LPS modification due to mutations in the PmrA/B two-component system. The results of this study indicate that loss of LPS expression results in collateral sensitivity to azithromycin, rifampicin and vancomycin, and that the six AMPs tested retain activity against LPS-deficient strains, indicating that these antibiotics may be viable treatment options for infections caused by these strains.
Collapse
|
29
|
Vila-Farrés X, Ferrer-Navarro M, Callarisa AE, Martí S, Espinal P, Gupta S, Rolain JM, Giralt E, Vila J. Loss of LPS is involved in the virulence and resistance to colistin of colistin-resistantAcinetobacter nosocomialismutants selectedin vitro. J Antimicrob Chemother 2015; 70:2981-6. [DOI: 10.1093/jac/dkv244] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 07/14/2015] [Indexed: 11/15/2022] Open
|
30
|
Bakour S, Olaitan AO, Ammari H, Touati A, Saoudi S, Saoudi K, Rolain JM. Emergence of Colistin- and Carbapenem-Resistant Acinetobacter baumannii ST2 Clinical Isolate in Algeria: First Case Report. Microb Drug Resist 2015; 21:279-85. [DOI: 10.1089/mdr.2014.0214] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Affiliation(s)
- Sofiane Bakour
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France
- Laboratoire d'Ecologie Microbienne, FSNV, Université de Bejaia, 06000 Bejaia, Algérie
| | - Abiola Olumuyiwa Olaitan
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France
| | - Houria Ammari
- Laboratoire Central de Biologie Médicale, Unité de Microbiologie, CHU Béni-Messous, Alger, Algérie
| | - Abdelaziz Touati
- Laboratoire d'Ecologie Microbienne, FSNV, Université de Bejaia, 06000 Bejaia, Algérie
| | - Souad Saoudi
- Laboratoire d'Ecologie Microbienne, FSNV, Université de Bejaia, 06000 Bejaia, Algérie
| | - Kenza Saoudi
- Laboratoire d'Ecologie Microbienne, FSNV, Université de Bejaia, 06000 Bejaia, Algérie
| | - Jean-Marc Rolain
- Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), UM 63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France
| |
Collapse
|
31
|
Colistin resistance mechanisms in Klebsiella pneumoniae strains from Taiwan. Antimicrob Agents Chemother 2015; 59:2909-13. [PMID: 25691646 DOI: 10.1128/aac.04763-14] [Citation(s) in RCA: 109] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 02/11/2015] [Indexed: 11/20/2022] Open
Abstract
Colistin is one of the antibiotics of last resort for the treatment of carbapenem-resistant Klebsiella pneumoniae infection. This study showed that capsular type K64 (50%) and ST11 (53.9%) are the prevalent capsular and sequence types in the colistin-resistant strains in Taiwan. The interruption of transcripts (38.5%) and amino acid mutation (15.4%) in mgrB are the major mechanisms contributing to colistin resistance. In addition, novel single amino acid changes in MgrB (Stop48Tyr) and PhoQ (Leu26Pro) were observed to contribute to colistin resistance.
Collapse
|