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Abstract
Multidrug-resistant A. baumannii are important Gram-negative pathogens causing persistent wound infections in both wounded and burned victims, which often result in secondary complications such as delayed wound healing, skin graft failure, and sometimes more serious outcomes such as sepsis and amputation. The choice of antibiotics to remediate these A. baumannii infections is becoming limited; and therefore, there has been a renewed interest in the research and development of new antibacterials targeting this pathogen. However, the evaluation of safety and efficacy is made more difficult by the lack of well-established in vivo models. This chapter describes established rodent and large animal models that have been used to investigate and develop treatments for A. baumannii skin and soft tissue infections.
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552
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Zurawski DV, Black CC, Alamneh YA, Biggemann L, Banerjee J, Thompson MG, Wise MC, Honnold CL, Kim RK, Paranavitana C, Shearer JP, Tyner SD, Demons ST. A Porcine Wound Model of Acinetobacter baumannii Infection. Adv Wound Care (New Rochelle) 2019; 8:14-27. [PMID: 30705786 PMCID: PMC6350066 DOI: 10.1089/wound.2018.0786] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/24/2018] [Indexed: 01/25/2023] Open
Abstract
Objective: To better understand Acinetobacter baumannii pathogenesis and to advance drug discovery against this pathogen, we developed a porcine, full-thickness, excisional, monospecies infection wound model. Approach: The research was facilitated with AB5075, a previously characterized, extensively drug-resistant A. baumannii isolate. The model requires cyclophosphamide-induced neutropenia to establish a skin and soft tissue infection (SSTI) that persists beyond 7 days. Multiple, 12-mm-diameter full-thickness wounds were created in the skin overlying the cervical and thoracic dorsum. Wound beds were inoculated with 5.0 × 104 colony-forming units (CFU) and covered with dressing. Results:A. baumannii was observed in the wound bed and on the dressing in what appeared to be biofilm. When bacterial burdens were measured, proliferation to at least 106 CFU/g (log106) wound tissue was observed. Infection was further characterized by scanning electron microscopy (SEM) and peptide nucleic acid fluorescence in situ hybridization (PNA-FISH) staining. To validate as a treatment model, polymyxin B was applied topically to a subset of infected wounds every 2 days. Then, the treated and untreated wounds were compared using multiple quantitative and qualitative techniques to include gross pathology, CFU burden, histopathology, PNA-FISH, and SEM. Innovation: This is the first study to use A. baumannii in a porcine model as the sole infectious agent. Conclusion: The porcine model allows for an additional preclinical assessment of antibacterial candidates that show promise against A. baumannii in rodent models, further evaluating safety and efficacy, and serve as a large animal in preclinical assessment for the treatment of SSTI.
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Affiliation(s)
- Daniel V. Zurawski
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Chad C. Black
- Experimental Therapeutics Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Yonas A. Alamneh
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Lionel Biggemann
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Jaideep Banerjee
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Mitchell G. Thompson
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Matthew C. Wise
- Veterinary Services Program, Department of Pathology, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Cary L. Honnold
- Veterinary Services Program, Department of Pathology, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Robert K. Kim
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Chrysanthi Paranavitana
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Jonathan P. Shearer
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Stuart D. Tyner
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
| | - Samandra T. Demons
- Wound Infections Department, Bacterial Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, Maryland
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553
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Isler B, Doi Y, Bonomo RA, Paterson DL. New Treatment Options against Carbapenem-Resistant Acinetobacter baumannii Infections. Antimicrob Agents Chemother 2019; 63:e01110-18. [PMID: 30323035 PMCID: PMC6325237 DOI: 10.1128/aac.01110-18] [Citation(s) in RCA: 166] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 10/08/2018] [Indexed: 01/08/2023] Open
Abstract
Carbapenem-resistant Acinetobacter baumannii (CRAB) is a perilous nosocomial pathogen causing substantial morbidity and mortality. Current treatment options for CRAB are limited and suffer from pharmacokinetic limitations, such as high toxicity and low plasma levels. As a result, CRAB is declared as the top priority pathogen by the World Health Organization for the investment in new drugs. This urgent need for new therapies, in combination with faster FDA approval process, accelerated new drug development and placed several drug candidates in the pipeline. This article reviews available information about the new drugs and other therapeutic options focusing on agents in clinical or late-stage preclinical studies for the treatment of CRAB, and it evaluates their expected benefits and potential shortcomings.
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Affiliation(s)
- Burcu Isler
- Istanbul Education and Research Hospital, Istanbul, Turkey
| | - Yohei Doi
- University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Robert A Bonomo
- Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Cleveland, Ohio, USA
- Case Western Reserve University Veterans Affairs Center of Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, Ohio, USA
| | - David L Paterson
- The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital Campus, Brisbane, Queensland, Australia
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554
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Vincent JL. Multidrug Resistant Gram-Negative Bacteria in Community-Acquired Pneumonia. ANNUAL UPDATE IN INTENSIVE CARE AND EMERGENCY MEDICINE 2019 2019. [PMCID: PMC7119995 DOI: 10.1007/978-3-030-06067-1_36] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Community-acquired pneumonia (CAP) is associated with high morbidity and mortality worldwide [1]. Although several different bacteria and respiratory viruses can be responsible for CAP, Streptococcus pneumoniae (pneumococcus) remains the most common causative pathogen. A small proportion of CAP cases are caused by Gram-negative bacteria, especially Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii and Stenotrophomona maltophilia [2, 3]. The main problem concerning the treatment of Gram-negative bacterial infections is their related antibiotic resistance, reported as multidrug resistant (MDR = resistant to at least one agent in three or more groups of antibiotics), extensively drug resistant (XDR = resistant to at least one agent in all but two or fewer groups of antibiotics) and pan-drug resistant (PDR = resistant to all groups of antibiotics) [4]. This makes the clinical management of pneumonia caused by such pathogens a challenge for physicians. Taking into account the clinical severity that may be associated with CAP caused by Gram-negative bacteria (respiratory failure, bacteremia, shock, acute respiratory distress syndrome [ARDS]) the magnitude of the global health problem is tremendous.
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Affiliation(s)
- Jean-Louis Vincent
- Dept. of Intensive Care, Erasme Hospital, Université libre de Bruxelles, Brussels, Belgium
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555
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Oliveira AGDMD, Melo L, Gomes DBC, Peixoto RS, Leite DCDA, Leite SGF, Colares LGT, Miguel MAL. Condições higiênico-sanitárias e perfil da comunidade microbiana de utensílios e mesas higienizadas de um serviço de alimentação localizado no Rio de Janeiro. BRAZILIAN JOURNAL OF FOOD TECHNOLOGY 2019. [DOI: 10.1590/1981-6723.09718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Resumo O objetivo deste estudo foi avaliar as condições higiênico-sanitárias e o perfil da comunidade microbiana dos utensílios e das mesas de um serviço de alimentação localizado no município do Rio de Janeiro. A caracterização do processo de higienização dos utensílios (pratos, bandejas e talheres) e das mesas foi realizada por observação sistemática. Verificou-se que os utensílios eram lavados em máquina de lavar e as mesas, manualmente. Após a higienização, os utensílios apresentavam umidade e resíduos de alimentos. Pelo método dependente de cultivo, foram analisadas 126 amostras higienizadas (utensílios: n=90 e mesas: n=36). Pesquisaram-se bactérias mesófilas, coliformes, Escherichia coli, Staphylococcus aureus e fungos. Das amostras analisadas, 100% dos utensílios e 80% das mesas apresentaram contagens microbianas superiores ao recomendado na literatura, estando em condições higiênico-sanitárias inadequadas. E. coli foi isolada nos utensílios e S. aureus, nas mesas. Pelos métodos independentes de cultivo (PCR-DGGE e sequenciamento da subunidade 16S do rRNA), foram analisadas 36 amostras (utensílios: n=27 e mesas: n=9). Klebsiella sp. e Acinetobacter sp. Foram detectadas em todas as amostras, Citrobacter sp. sobre as mesas e Aeromonas hydrophila, nos talheres. Houve falha no processo de higienização, que foi confirmada pelas análises realizadas, que evidenciaram a presença de microrganismos indicadores e patogênicos, que podem causar a perda da qualidade das refeições, assim como danos à saúde dos comensais. Desta forma, é necessário adequar o processo de higienização, a fim de minimizar o risco de contaminação e o surto de doenças transmitidas por alimentos (DTA).
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Affiliation(s)
| | - Lauro Melo
- Universidade Federal do Rio de Janeiro, Brasil
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556
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Kheshti R, Pourabbas B, Mosayebi M, Vazin A. In vitro activity of colistin in combination with various antimicrobials against Acinetobacter baumannii species, a report from South Iran. Infect Drug Resist 2018; 12:129-135. [PMID: 30643441 PMCID: PMC6318711 DOI: 10.2147/idr.s182585] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Introduction Acinetobacter baumannii is a gram-negative,opportunistic pathogen responsible for resistant nosocomial infections especially in the intensive care units (ICUS).One reason for the failure in the treatment of A. baumannii is its ability of develop resistance against several antimicrobials. combination of different antimicrobials can be used to overcome such a resistance. This study was done to evaluate the in vitro synergistic activity of colistin in combination with six different antimicrobials, including ciprofloxacin, levofloxacin, imipenem, meropenem, ampicillin-sulbactam, and rifampin against A. baumannii species isolated from blood culture of patients admitted to ICUs of Nemazee hospital, Shiraz, Iran. Method After performing biochemical identification assays on 20 isolates of A. baumannii, minimum inhibitory concentrations were determined by E- test method and antibiotic interactions were assessed using broth microdilution checkerboard method. Results Combinations of colistin with all six studied antimicrobials had some synergistic effect. Conclusion clinical studies are required to clarify the therapeutic potential of these antimicrobial combinations
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Affiliation(s)
- Raziyeh Kheshti
- Department of Clinical Pharmacy, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran,
| | - Bahman Pourabbas
- Professor Alborzi Clinical Microbiology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran,
| | - Maryam Mosayebi
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Afsaneh Vazin
- Department of Clinical Pharmacy, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran,
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557
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OXA-23 Is a Prevalent Mechanism Contributing to Sulbactam Resistance in Diverse Acinetobacter baumannii Clinical Strains. Antimicrob Agents Chemother 2018; 63:AAC.01676-18. [PMID: 30348663 DOI: 10.1128/aac.01676-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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558
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Acinetobacter baumannii OxyR Regulates the Transcriptional Response to Hydrogen Peroxide. Infect Immun 2018; 87:IAI.00413-18. [PMID: 30297527 DOI: 10.1128/iai.00413-18] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 10/03/2018] [Indexed: 12/21/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative opportunistic pathogen that causes diverse infections, including pneumonia, bacteremia, and wound infections. Due to multiple intrinsic and acquired antimicrobial-resistance mechanisms, A. baumannii isolates are commonly multidrug resistant, and infections are notoriously difficult to treat. The World Health Organization recently highlighted carbapenem-resistant A. baumannii as a "critical priority" for the development of new antimicrobials because of the risk to human health posed by this organism. Therefore, it is important to discover the mechanisms used by A. baumannii to survive stresses encountered during infection in order to identify new drug targets. In this study, by use of in vivo imaging, we identified hydrogen peroxide (H2O2) as a stressor produced in the lung during A. baumannii infection and defined OxyR as a transcriptional regulator of the H2O2 stress response. Upon exposure to H2O2, A. baumannii differentially transcribes several hundred genes. However, the transcriptional upregulation of genes predicted to detoxify hydrogen peroxide is abolished in an A. baumannii strain in which the transcriptional regulator oxyR is genetically inactivated. Moreover, inactivation of oxyR in both antimicrobial-susceptible and multidrug-resistant A. baumannii strains impairs growth in the presence of H2O2 OxyR is a direct regulator of katE and ahpF1, which encode the major H2O2-degrading enzymes in A. baumannii, as confirmed through measurement of promoter binding by recombinant OxyR in electromobility shift assays. Finally, an oxyR mutant is less fit than wild-type A. baumannii during infection of the murine lung. This work reveals a mechanism used by this important human pathogen to survive H2O2 stress encountered during infection.
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559
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CpaA Is a Glycan-Specific Adamalysin-like Protease Secreted by Acinetobacter baumannii That Inactivates Coagulation Factor XII. mBio 2018; 9:mBio.01606-18. [PMID: 30563903 PMCID: PMC6299215 DOI: 10.1128/mbio.01606-18] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Ventilator-associated pneumonia and catheter-related bacteremia are the most common and severe infections caused by Acinetobacter baumannii. Besides the capsule, lipopolysaccharides, and the outer membrane porin OmpA, little is known about the contribution of secreted proteins to A. baumannii survival in vivo. Here we focus on CpaA, a potentially recently acquired virulence factor that inhibits blood coagulation in vitro. We identify coagulation factor XII as a target of CpaA, map the cleavage sites, and show that glycosylation is a prerequisite for CpaA-mediated inactivation of factor XII. We propose adding CpaA to a small, but growing list of bacterial proteases that are specific for highly glycosylated components of the host defense system. Antibiotic-resistant Acinetobacter baumannii is increasingly recognized as a cause of difficult-to-treat nosocomial infections, including pneumonia, wound infections, and bacteremia. Previous studies have demonstrated that the metalloprotease CpaA contributes to virulence and prolongs clotting time when added to human plasma as measured by the activated partial thromboplastin time (aPTT) assay. Here, we show that CpaA interferes with the intrinsic coagulation pathway, also called the contact activation system, in human as well as murine plasma, but has no discernible effect on the extrinsic pathway. By utilizing a modified aPTT assay, we demonstrate that coagulation factor XII (fXII) is a target of CpaA. In addition, we map the cleavage by CpaA to two positions, 279-280 and 308-309, within the highly glycosylated proline-rich region of human fXII, and show that cleavage at the 308-309 site is responsible for inactivation of fXII. At both sites, cleavage occurs between proline and an O-linked glycosylated threonine, and deglycosylation of fXII prevents cleavage by CpaA. Consistent with this, mutant fXII (fXII-Thr309Lys) from patients with hereditary angioedema type III (HAEIII) is protected from CpaA inactivation. This raises the possibility that individuals with HAEIII who harbor this mutation may be partially protected from A. baumannii infection if CpaA contributes to human disease. By inactivating fXII, CpaA may attenuate important antimicrobial defense mechanisms such as intravascular thrombus formation, thus allowing A. baumannii to disseminate.
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560
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Fernandez-Garcia L, Ambroa A, Blasco L, Bleriot I, López M, Alvarez-Marin R, Fernández-Cuenca F, Martinez-Martinez L, Vila J, Rodríguez-Baño J, Garnacho-Montero J, Cisneros JM, Pascual A, Pachón J, Bou G, Smani Y, Tomás M. Relationship Between the Quorum Network (Sensing/Quenching) and Clinical Features of Pneumonia and Bacteraemia Caused by A. baumannii. Front Microbiol 2018; 9:3105. [PMID: 30619184 PMCID: PMC6304438 DOI: 10.3389/fmicb.2018.03105] [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: 09/22/2018] [Accepted: 11/30/2018] [Indexed: 01/22/2023] Open
Abstract
Acinetobacter baumannii (Ab) is one of the most important pathogens associated with nosocomial infections, especially pneumonia. Interest in the Quorum network, i.e., Quorum Sensing (QS)/Quorum Quenching (QQ), in this pathogen has grown in recent years. The Quorum network plays an important role in regulating diverse virulence factors such as surface motility and bacterial competition through the type VI secretion system (T6SS), which is associated with bacterial invasiveness. In the present study, we investigated 30 clinical strains of A. baumannii isolated in the “II Spanish Study of A. baumannii GEIH-REIPI 2000-2010” (Genbank Umbrella Bioproject PRJNA422585), a multicentre study describing the relationship between the Quorum network in A. baumannii and the development of pneumonia and associated bacteraemia. Expression of the aidA gene (encoding the AidA protein, QQ enzyme) was lower (P < 0.001) in strains of A. baumannii isolated from patients with bacteraemic pneumonia than in strains isolated from patients with non-bacteraemic pneumonia. Moreover, aidA expression in the first type of strain was not regulated in the presence of environmental stress factors such as the 3-oxo-C12-HSL molecule (substrate of AidA protein, QQ activation) or H2O2 (inhibitor of AidA protein, QS activation). However, in the A. baumannii strains isolated from patients with non-bacteraemic pneumonia, aidA gene expression was regulated by stressors such as 3-oxo-C12-HSL and H2O2. In an in vivo Galleria mellonella model of A. baumannii infection, the A. baumannii ATCC 17978 strain was associated with higher mortality (100% at 24 h) than the mutant, abaI-deficient, strain (carrying a synthetase enzyme of Acyl homoserine lactone molecules) (70% at 24 h). These data suggest that the QS (abaR and abaI genes)/QQ (aidA gene) network affects the development of secondary bacteraemia in pneumonia patients and also the virulence of A. baumannii.
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Affiliation(s)
- Laura Fernandez-Garcia
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Antón Ambroa
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Lucia Blasco
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Ines Bleriot
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Maria López
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Rocio Alvarez-Marin
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University Seville, Seville, Spain
| | - Felipe Fernández-Cuenca
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Department of Microbiology and Medicine, Biomedicine Institute of Seville, Hospital Universitario Virgen Macarena, University of Seville, Seville, Spain
| | - Luis Martinez-Martinez
- Unit of Microbiology, Department of Microbiology, Maimonides Biomedical Research Institute of Cordoba, University Hospital Reina Sofía, University of Córdoba, Córdoba, Spain
| | - Jordi Vila
- Institute of Global Health of Barcelona (ISGlobal), Hospital Clínic - Universitat de Barcelona, Barcelona, Spain
| | - Jesús Rodríguez-Baño
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Department of Microbiology and Medicine, Biomedicine Institute of Seville, Hospital Universitario Virgen Macarena, University of Seville, Seville, Spain
| | - Jose Garnacho-Montero
- Intensive Care Clinical Unit-Institute of Biomedicine of Seville (IBIS), Hospital Virgen Macarena, Seville, Spain
| | - Jose Miguel Cisneros
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University Seville, Seville, Spain
| | - Alvaro Pascual
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Department of Microbiology and Medicine, Biomedicine Institute of Seville, Hospital Universitario Virgen Macarena, University of Seville, Seville, Spain
| | - Jeronimo Pachón
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University Seville, Seville, Spain.,Department of Medicine, University of Seville, Seville, Spain
| | - German Bou
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
| | - Younes Smani
- Clinical Unit for Infectious Diseases, Microbiology and Preventive Medicine, Institute of Biomedicine of Seville (IBIS), University Hospital Virgen del Rocío/CSIC/University Seville, Seville, Spain
| | - Maria Tomás
- Microbiology Department-Biomedical Research Institute A Coruña (INIBIC), Hospital A Coruña (CHUAC), University of A Coruña (UDC), A Coruña, Spain
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561
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Jain M, Sharma A, Sen MK, Rani V, Gaind R, Suri JC. Phenotypic and molecular characterization of Acinetobacter baumannii isolates causing lower respiratory infections among ICU patients. Microb Pathog 2018; 128:75-81. [PMID: 30562602 DOI: 10.1016/j.micpath.2018.12.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 11/16/2018] [Accepted: 12/11/2018] [Indexed: 11/18/2022]
Abstract
BACKGROUND Multi-drug resistant Acinetobacter baumannii has emerged as important nosocomial pathogen associated with various infections including lower respiratory tract. Limited therapeutic options contribute to increased morbidity and mortality. Acinetobacter baumannii has the ability to persist in the environment for prolonged periods. Breach in infection control practices increases the chances of cross transmission between patients and inter/intraspecies transmission of resistance elements. The present prospective work was conducted among patients with lower respiratory tract infections (LRTI) in the intensive care unit (ICU) to study the etiology with special reference to Acinetobacter baumannii and the role of immediate patient environment in the ICU as possible source of infection. Acinetobacter baumannii were characterized for antimicrobial susceptibility, mechanism of carbapenem resistance and virulence determinants. Molecular typing of the clinical and environmental isolates was undertaken to study the probable modes of transmission. MATERIALS AND METHODS Appropriate respiratory samples from 107 patients with LRTI admitted to ICU during September 2016 to March 2017 were studied for likely bacterial pathogens. Environmental samples (n = 71) were also screened. All the samples were processed using conventional microbiological methods. Consecutive Acinetobacter spp. isolated from clinical and environmental (health care workers and environment from ICU) samples were included in the study. Antimicrobial susceptibility was performed as per CLSI guidelines. Carbapenem resistance, mediated by carbapenemase genes (blaOXA-23-like,blaOXA-24-like,blaOXA-58-like and blaNDM-1) were studied by PCR. Biofilm forming ability was tested phenotypically using microtitre plate method. Pulse Field Gel Electrophoresis (PFGE) was used to study clonality of the clinical and environmental isolates. RESULTS The prevalence of Acinetobacter baumannii was 26.2% (28/107) and 11.26% (8/71) among patients with LRTI and environmental samples respectively. The carbapenem resistance was high, 96.42% (27/28) and 87.5% (7/8) in clinical and environmental isolates respectively. The most common carbapenemase associated with resistance was blaOXA-23-like gene followed by blaNDM-1 among both the clinical and environmental isolates. All isolates were sensitive to colistin (MIC ≤ 1 μg/ml). Biofilm production was observed among all clinical (n = 28) and 87.5% (7/8) of the environmental isolates. Line listing of the cases suggests the occurrence of infections throughout the study period with no significant clustering. On PFGE, 12 clusters were observed and 16/36 isolates were present in one single cluster that included both clinical and environmental isolates which were either carbapenem resistant or sensitive. DISCUSSION Carbapenem resistant Acinetobacter baumannii (CRAB) is an important cause of LRTI in the ICU. PFGE suggests spread of carbapenem resistant isolates via cross transmission among patients and the environment. The detection of blaNDM-1 gene among Acinetobacter baumannii and existence of carbapenem resistant and sensitive isolates within the same clones suggests horizontal transmission of resistant genes among various bacterial species. The ability of Acinetobacter baumannii to form biofilms may contribute to its persistence in the environment. This along with breach in infection control practices are the likely factors contributing to this transmission. This information can be used to strengthen and monitor infection control (IC) and the hospital cleaning and disinfection practices to prevent spread of resistant organisms within the ICU. Colistin remains drug of choice for management of CRAB.
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Affiliation(s)
- Manisha Jain
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India
| | - Amit Sharma
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India
| | - M K Sen
- Department of Pulmonary, Critical Care & Sleep Medicine, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India
| | - Vandana Rani
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India
| | - Rajni Gaind
- Department of Microbiology, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India.
| | - J C Suri
- Department of Pulmonary, Critical Care & Sleep Medicine, Vardhman Mahavir Medical College and Safdarjung Hospital, Delhi, India
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562
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Role of Capsule in Resistance to Disinfectants, Host Antimicrobials, and Desiccation in Acinetobacter baumannii. Antimicrob Agents Chemother 2018; 62:AAC.01188-18. [PMID: 30297362 DOI: 10.1128/aac.01188-18] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 09/25/2018] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii strain AB5075 forms two cell types distinguished by their opaque (VIR-O) or translucent (AV-T) colonies. VIR-O cells possess a thicker capsule and are more resistant to a variety of stressors than AV-T cells. However, the direct role of the capsule in these stressors was unknown. This study demonstrates that the capsule is required for resistance to disinfectants, lysozyme, and desiccation in Acinetobacter baumannii In addition, the capsule is required for survival in a mouse lung model of infection.
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563
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Uchiyama S, Dahesh S, Nizet V, Kessler J. Enhanced topical delivery of non-complexed molecular iodine for Methicillin-resistant Staphylococcus aureus decolonization. Int J Pharm 2018; 554:81-86. [PMID: 30395958 DOI: 10.1016/j.ijpharm.2018.11.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 10/29/2018] [Accepted: 11/02/2018] [Indexed: 02/05/2023]
Abstract
Staphylococcus aureus, a leading cause of serious human infections in both healthcare and community settings, is increasingly difficult to control due to expanding resistance to multiple antibiotic classes. Methicillin-resistant S. aureus (MRSA) strains have disseminated on a global scale and are associated with adverse patient outcomes, increased hospital stays, and significant economic costs to the healthcare system. A proximal step in S. aureus infection is colonization of the nasal mucosa, and effective strategies to decolonize high risk patients to reduce the risk of invasive infection and nosocomial spread represent an important clinical priority. With rising resistance to mupirocin, the most common antibiotic utilized for nasal MRSA decontamination, we are examining the use of pure molecular iodine (I2)-based formulations for this indication. Recently, an iodophor formulation of povidone-iodine (PVP-I) has shown significant promise for nasal MRSA decontamination by swabbing the anterior nares of patients in hospital settings, but the I2 concentration in this treatment is less than 0.01% of total iodine species present and like all providone-iodine formulations causes skin staining. Here we determine that a novel non-staining formulation of I2 combined with the safe organic emollient glycerin delivers high local concentrations of the active antimicrobial entity (I2) with minimal evaporative loss, exhibits activity at ∼1 part per million against MRSA and other important Gram-positive and -negative human pathogens. This formulation for I2 topical delivery produced similar reductions in mean bacterial burden and was associated with fewer treatment failures (<2-logfold reduction) than PVP-I in a murine model of MRSA nasal decontamination. Formulations of I2 in glycerin emollient merit further exploration as topical disinfectants for human medical indications.
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Affiliation(s)
- Satoshi Uchiyama
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093-0760, USA
| | - Samira Dahesh
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093-0760, USA
| | - Victor Nizet
- Division of Host-Microbe Systems and Therapeutics, Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093-0760, USA; Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093-0760, USA.
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564
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Hamidian M, Hall RM. The AbaR antibiotic resistance islands found in Acinetobacter baumannii global clone 1 - Structure, origin and evolution. Drug Resist Updat 2018; 41:26-39. [PMID: 30472242 DOI: 10.1016/j.drup.2018.10.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 10/15/2018] [Accepted: 10/30/2018] [Indexed: 11/28/2022]
Abstract
In multiply resistant Acinetobacter baumannii, complex transposons located in the chromosomal comM gene carry antibiotic and heavy metal resistance determinants. For one type, known collectively as AbaR, the ancestral form, AbaR0, entered a member of global clone 1 (GC1) in the mid 1970s and continued to evolve in situ forming many variants. In AbaR0, antibiotic and mercuric ion resistance genes are located between copies of a cadmium-zinc resistance transposon, Tn6018, and this composite transposon is in a class III transposon, Tn6019, carrying arsenate/arsenite resistance genes and five tni transposition genes. The antibiotic resistance genes in the AbaR0 and derived AbaR3 configurations are aphA1b, blaTEM, catA1, sul1, tetA(A), and cassette-associated aacC1 and aadA1 genes. These genes are in a specific arrangement of fragments from well-known transposons, e.g. Tn1, Tn1721, Tn1696 and Tn2670, that arose in an IncM1 plasmid. All known GC1 lineage 1 isolates carry AbaR0 or AbaR3, which arose around 1990, or a variant derived from one of them. Variants arose via deletions caused by one of three internal IS26s, by recombination between duplicate copies of sul1 or Tn6018, or by gene cassette addition or replacement. A few GC2 isolates also carry an AbaR island with different cassette-associated genes, aacA4 and oxa20.
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Affiliation(s)
- Mohammad Hamidian
- School of Molecular and Microbial Biosciences, The University of Sydney, NSW 2006, Australia; The ithree institute, University of Technology Sydney, Ultimo 2007, NSW, Australia
| | - Ruth M Hall
- School of Molecular and Microbial Biosciences, The University of Sydney, NSW 2006, Australia.
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565
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Davies-Sala C, Jani S, Zorreguieta A, Tolmasky ME. Identification of the Acinetobacter baumannii Ribonuclease P Catalytic Subunit: Cleavage of a Target mRNA in the Presence of an External Guide Sequence. Front Microbiol 2018; 9:2408. [PMID: 30349524 PMCID: PMC6186949 DOI: 10.3389/fmicb.2018.02408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 09/20/2018] [Indexed: 11/17/2022] Open
Abstract
The bacterial ribonuclease P or RNase P holoenzyme is usually composed of a catalytic RNA subunit, M1, and a cofactor protein, C5. This enzyme was first identified for its role in maturation of tRNAs by endonucleolytic cleavage of the pre-tRNA. The RNase P endonucleolytic activity is characterized by having structural but not sequence substrate requirements. This property led to development of EGS technology, which consists of utilizing a short antisense oligonucleotide that when forming a duplex with a target RNA induces its cleavage by RNase P. This technology is being explored for designing therapies that interfere with expression of genes, in the case of bacterial infections EGS technology could be applied to target essential, virulence, or antibiotic resistant genes. Acinetobacter baumannii is a problematic pathogen that is commonly resistant to multiple antibiotics, and EGS technology could be utilized to design alternative therapies. To better understand the A. baumannii RNase P we first identified and characterized the catalytic subunit. We identified a gene coding for an RNA species, M1Ab, with the expected features of the RNase P M1 subunit. A recombinant clone coding for M1Ab complemented the M1 thermosensitive mutant Escherichia coli BL21(DE3) T7A49, which upon transformation was able to grow at the non-permissive temperature. M1Ab showed in vitro catalytic activity in combination with the C5 protein cofactor from E. coli as well as with that from A. baumannii, which was identified, cloned and partially purified. M1Ab was also able to cleave a target mRNA in the presence of an EGS with efficiency comparable to that of the E. coli M1, suggesting that EGS technology could be a viable option for designing therapeutic alternatives to treat multiresistant A. baumannii infections.
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Affiliation(s)
- Carol Davies-Sala
- Center for Applied Biotechnology Studies, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States.,Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.,Facultad de Ciencias Exactas y Naturales de la Universidad de Buenos Aires, University of Buenos Aires, Buenos Aires, Argentina
| | - Saumya Jani
- Center for Applied Biotechnology Studies, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
| | - Angeles Zorreguieta
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.,Facultad de Ciencias Exactas y Naturales de la Universidad de Buenos Aires, University of Buenos Aires, Buenos Aires, Argentina
| | - Marcelo E Tolmasky
- Center for Applied Biotechnology Studies, College of Natural Sciences and Mathematics, California State University, Fullerton, Fullerton, CA, United States
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566
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Plasma and Intrapulmonary Concentrations of ETX2514 and Sulbactam following Intravenous Administration of ETX2514SUL to Healthy Adult Subjects. Antimicrob Agents Chemother 2018; 62:AAC.01089-18. [PMID: 30126953 DOI: 10.1128/aac.01089-18] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Accepted: 08/11/2018] [Indexed: 01/19/2023] Open
Abstract
ETX2514 is a novel β-lactamase inhibitor that broadly inhibits Ambler class A, C, and D β-lactamases. ETX2514 combined with sulbactam (SUL) in vitro restores sulbactam activity against Acinetobacter baumannii ETX2514-sulbactam (ETX2514SUL) is under development for the treatment of A. baumannii infections. The objective of this study was to determine and compare plasma, epithelial lining fluid (ELF), and alveolar macrophage (AM) concentrations following intravenous (i.v.) ETX2514 and sulbactam. Plasma, ELF, and AM concentrations of ETX2514 and sulbactam were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS) in 30 healthy adult subjects following repeated dosing (ETX2514 [1 g] and sulbactam [1 g] every 6 h [q6h], as a 3-h i.v. infusion, for a total of 3 doses). A bronchoalveolar lavage (BAL) was performed once in each subject at either 1, 2.5, 3.25, 4, or 6 h after the start of the last infusion. Penetration ratios were calculated from area under the concentration-time curve from 0 to 6 h (AUC0-6) values for total plasma and ELF using mean and median concentrations at the BAL fluid sampling times. Respective ELF AUC0-6 values, based on mean and median concentrations, were 40.1 and 39.4 mg · h/liter for ETX2514 and 34.7 and 34.5 mg · h/liter for sulbactam. Respective penetration ratios of ELF to total/unbound plasma concentrations, based on mean and median AUC0-6 values, of ETX2514 were 0.37/0.41 and 0.36/0.40, whereas these same ratio values were 0.50/0.81 and 0.50/0.80 for sulbactam. ETX2514 and sulbactam concentrations in AM were measurable and fairly constant throughout the dosing interval (median values of 1.31 and 1.01 mg/liter, respectively). These data support further study of ETX2514SUL for the treatment of pneumonia caused by multidrug-resistant A. baumannii (This study has been registered at ClinicalTrials.gov under identifier NCT03303924.).
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567
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Ahmad S, Shaker B, Ahmad F, Raza S, Azam SS. Moleculer dynamics simulaiton revealed reciever domain of Acinetobacter baumannii BfmR enzyme as the hot spot for future antibiotics designing. J Biomol Struct Dyn 2018; 37:2897-2912. [DOI: 10.1080/07391102.2018.1498805] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- Sajjad Ahmad
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Bilal Shaker
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Faisal Ahmad
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Saad Raza
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
| | - Syed Sikander Azam
- Computational Biology Lab, National Center for Bioinformatics, Quaid-i-Azam University, Islamabad, Pakistan
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568
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Choi SH, Cho EB, Chung JW, Lee MK. Changes in the early mortality of adult patients with carbapenem-resistant Acinetobacter baumannii bacteremia during 11 years at an academic medical center. J Infect Chemother 2018; 25:6-11. [PMID: 30342838 DOI: 10.1016/j.jiac.2018.09.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 09/13/2018] [Accepted: 09/23/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND In the past decade, carbapenem-resistant Acinetobacter baumannii (CRAB) has emerged as a major pathogen of serious infections in critically ill adult patients. Despite very limited antimicrobial options, clinicians have sought to reduce the mortality of patients with serious CRAB infections. To determine whether these long-term efforts effectively lessened the mortality of such patients, we investigated changes in the early mortality of adult patients with CRAB bacteremia and related clinical factors. METHODS We reviewed clinical data from 111 adult patients with monomicrobial CRAB bacteremia admitted to an academic medical center between 2006 and 2016. RESULTS The 14-day mortality rate from 2013 to 2016 was lower than that from 2009 to 2012 (43.4% vs. 71.1%, p = 0.01). When the clinical characteristics of adult patients with CRAB bacteremia from 2013 to 2016 were compared to those of the patients from 2009 to 2012, chronic lung disease (6.7% vs. 24.4%, p = 0.01), a recent history of mechanical ventilation (38.3% vs. 57.8%, p = 0.048), and pneumonia (48.3% vs. 68.9%, p = 0.04) were less frequent in 2013-2016, while neurological disease (43.3% vs. 22.2%, p = 0.02), central venous catheter infection (20.0% vs. 6.7%, p = 0.05), and early appropriate antimicrobial therapy (46.7% vs. 24.4%, p = 0.01) were more frequent. CONCLUSION The 14-day mortality rate of adult patients with CRAB bacteremia was reduced during 2013-2016. This decrease was associated with early appropriate antimicrobial therapy and a lower proportion of patients with bacteremic pneumonia, which seemed to result from improved hospital infection control during that time period.
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Affiliation(s)
- Seong-Ho Choi
- Division of Infectious Diseases, Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Eun Been Cho
- Division of Infectious Diseases, Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
| | - Jin-Won Chung
- Division of Infectious Diseases, Department of Internal Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea.
| | - Mi-Kyung Lee
- Department of Laboratory Medicine, Chung-Ang University Hospital, Chung-Ang University College of Medicine, Seoul, Republic of Korea
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569
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Ghosh M, Lin YM, Miller PA, Möllmann U, Boggess WC, Miller MJ. Siderophore Conjugates of Daptomycin are Potent Inhibitors of Carbapenem Resistant Strains of Acinetobacter baumannii. ACS Infect Dis 2018; 4:1529-1535. [PMID: 30043609 DOI: 10.1021/acsinfecdis.8b00150] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Development of resistance to antibiotics is a major medical problem. One approach to extending the utility of our limited antibiotic arsenal is to repurpose antibiotics by altering their bacterial selectivity. Many antibiotics that are used to treat infections caused by Gram-positive bacteria might be made effective against Gram-negative bacterial infections, if they could circumvent permeability barriers and antibiotic deactivation processes associated with Gram-negative bacteria. Herein, we report that covalent attachment of the normally Gram-positive-only antibiotic, daptomycin, with iron sequestering siderophore mimetics that are recognized by Gram-negative bacteria, provides conjugates that are active against virulent strains of Acinetobacter baumannii, including carbapenemase and cephalosporinase producers. The result is the generation of a new set of antibiotics designed to target bacterial infections that have been designated as being of dire concern.
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Affiliation(s)
- Manuka Ghosh
- Hsiri Therapeutics, Rosetree Corporate Center, 1400 N. Providence Road, Building 1, Suite 115S, Media, Pennsylvania 19063, United States
| | - Yun-Ming Lin
- Hsiri Therapeutics, Rosetree Corporate Center, 1400 N. Providence Road, Building 1, Suite 115S, Media, Pennsylvania 19063, United States
| | - Patricia A. Miller
- Hsiri Therapeutics, Rosetree Corporate Center, 1400 N. Providence Road, Building 1, Suite 115S, Media, Pennsylvania 19063, United States
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Ute Möllmann
- Hsiri Therapeutics, Rosetree Corporate Center, 1400 N. Providence Road, Building 1, Suite 115S, Media, Pennsylvania 19063, United States
| | - William C. Boggess
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Marvin J. Miller
- Hsiri Therapeutics, Rosetree Corporate Center, 1400 N. Providence Road, Building 1, Suite 115S, Media, Pennsylvania 19063, United States
- Department of Chemistry and Biochemistry, 251 Nieuwland Science Hall, University of Notre Dame, Notre Dame, Indiana 46556, United States
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570
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Farrow JM, Wells G, Pesci EC. Desiccation tolerance in Acinetobacter baumannii is mediated by the two-component response regulator BfmR. PLoS One 2018; 13:e0205638. [PMID: 30308034 PMCID: PMC6181384 DOI: 10.1371/journal.pone.0205638] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 09/28/2018] [Indexed: 12/03/2022] Open
Abstract
For the opportunistic pathogen Acinetobacter baumannii, desiccation tolerance is thought to contribute significantly to the persistence of these bacteria in the healthcare environment. We investigated the ability of A. baumannii to survive rapid drying, and found that some strains exhibited a profoundly desiccation-resistant phenotype, characterized by the ability of a large proportion of cells to survive on a dry surface for an extended period of time. However, this phenotype was only displayed during the stationary phase of growth. Most interestingly, we found that drying resistance could be lost after extended cultivation in liquid medium. Genome sequencing of isolates that became drying-sensitive identified mutations in bfmR, which encodes a two-component response regulator that is important for A. baumannii virulence. Additionally, BfmR was necessary for the expression of stress-related proteins during stationary phase, and one of these, KatE, was important for long-term drying survival. These results suggested that BfmR may control stress responses, and we demonstrated that the ΔbfmR mutant was more sensitive to hydrogen peroxide, nutrient starvation, and increased osmolarity. We also found that cross-protection against drying could be stimulated by either starvation, which required BfmR, or increased osmolarity. These results imply that BfmR plays a role in controlling stress responses in A. baumannii which help protect cells during desiccation, and they provide a regulatory link between this organism’s ability to persist in the environment and pathogenicity.
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Affiliation(s)
- John M. Farrow
- Department of Microbiology and Immunology, The Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
| | - Greg Wells
- Department of Microbiology and Immunology, The Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
| | - Everett C. Pesci
- Department of Microbiology and Immunology, The Brody School of Medicine at East Carolina University, Greenville, North Carolina, United States of America
- * E-mail:
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571
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Lee H, Song WY, Kim M, Lee MW, Kim S, Park YS, Kwak K, Oh MH, Kim HJ. Synthesis and Characterization of Anguibactin To Reveal Its Competence To Function as a Thermally Stable Surrogate Siderophore for a Gram-Negative Pathogen, Acinetobacter baumannii. Org Lett 2018; 20:6476-6479. [DOI: 10.1021/acs.orglett.8b02789] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haeun Lee
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Woon Young Song
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Minju Kim
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Korea University, Seoul 02841, Republic of Korea
| | - Min Wook Lee
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Soojeung Kim
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Ye Song Park
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Kyungwon Kwak
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Korea University, Seoul 02841, Republic of Korea
| | - Man Hwan Oh
- Department of Nanobiomedical Science, Dankook University, Cheonan 31116, Republic of Korea
| | - Hak Joong Kim
- Department of Chemistry, Korea University, 145 Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
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572
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Salimizand H, Zomorodi AR, Mansury D, Khakshoor M, Azizi O, Khodaparast S, Baseri Z, Karami P, Zamanlou S, Farsiani H, Amini Y, Moradi B, Meshkat Z, Salimizand H, Hasanzadeh S, Sadeghian H. Diversity of aminoglycoside modifying enzymes and 16S rRNA methylases in Acinetobacter baumannii and Acinetobacter nosocomialis species in Iran; wide distribution of aadA1 and armA. INFECTION GENETICS AND EVOLUTION 2018; 66:195-199. [PMID: 30292703 DOI: 10.1016/j.meegid.2018.09.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/12/2018] [Accepted: 09/30/2018] [Indexed: 10/28/2022]
Abstract
PURPOSE Acinetobacter baumannii-calcoaceticus complex (ABC) make a great burden on health-care systems due to hospital-acquired infections and antibacterial resistance. Aminoglycoside in combination with other antibacterials used as treatment options. However, ABC species overcome this class of antibacterials in different ways. This study provides a comprehensive report on the distribution of aminoglycoside modifying enzymes (AMEs) and 16S rRNA methylase in Acinetobacter baumannii and Acinetobacter nosocomialis isolated from various provinces in Iran. METHODS During six month of study, from eight referral centers in seven provinces across the country, Iran, 178 A. baumannii and 43 A. nosocomialis isolates were collected. The minimum inhibitory concentration of amikacin, gentamicin, netilmicin, kanamycin and tobramycin were measured by microbroth dilution method. AMEs and 16S rRNA methylase variants were sought by PCR. RESULTS High rates of resistance were seen in all centers. MIC50 and MIC90 for all A. baumannii and A. nosocomialis isolates from different centers were > 512 mg/L. The most frequent AME was ant(3″)-Ia (aadA1) in both of A. baumannii (74.1%) and A. nosocomialis (86%). armA was detected in A. baumannii and A. nosocomialis at the frequency of 41.6% and 67.4%, respectively. rmtA, B, C, D, aac(3)-Ia (aacC1) and aac(6')-Im were not detected, neither in A. baumannii nor A. nosocomialis. Moreover, aac(6')-Ih was only found in A. baumannii isolates. The distribution of some of the ARGs was limited to a definite center. CONCLUSION The overall high-level carriage of ARGs in Acinetobacter species may limited usage of this class of antibacterials as a treatment option.
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Affiliation(s)
- Himen Salimizand
- Liver and Digestive Research Center, Kurdistan University of Medical Sciences, Sanandaj, Iran; Department of Microbiology, Faculty of Medicine, Kurdistan University of medical Sciences, Sanandaj, Iran
| | - Abolfazl Raafati Zomorodi
- Department of Pathobiology, Faculty of Veterinary Medicine, Ferdowsi university of Mashhad, Mashhad, Iran
| | - Davood Mansury
- Student Research Committee, Faculty of Medicine, Mashhad, University of Medical Sciences, Mashhad, Iran; Antimicrobial Resistance Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Microbiology and Virology, Medical School, Mashhad University of medical Sciences, Mashhad, Iran
| | - Mostafa Khakshoor
- Microbiology Department, Faculty of science, Islamic Azad University of Tonekabon, Iran
| | - Omid Azizi
- Department of Laboratory Sciences, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran
| | - Sepideh Khodaparast
- Department of bacteriology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran; Molecular laboratory, Shariati hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Zohre Baseri
- Molecular laboratory, Shariati hospital, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Pezhman Karami
- Department of Microbiology, Faculty of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran; Brucellosis Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Sajjad Zamanlou
- Department of Microbiology, Faculty of Medicine, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hadi Farsiani
- Antimicrobial Resistance Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Microbiology and Virology, Medical School, Mashhad University of medical Sciences, Mashhad, Iran
| | - Yousef Amini
- Department of Microbiology, Medical school, Zahedan University of medical Sciences, Zahedan, Iran; Infectious Diseases and Tropical Medicine Research Center, Zahedan University of Medical Sciences, Zahedan, Iran
| | - Bagher Moradi
- Esfarayen University of Medical Sciences, Esfarayen, Iran
| | - Zahra Meshkat
- Antimicrobial Resistance Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Microbiology and Virology, Medical School, Mashhad University of medical Sciences, Mashhad, Iran
| | - Hana Salimizand
- Department of Biology, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran
| | - Sepideh Hasanzadeh
- Student Research Committee, Faculty of Medicine, Mashhad, University of Medical Sciences, Mashhad, Iran; Antimicrobial Resistance Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Microbiology and Virology, Medical School, Mashhad University of medical Sciences, Mashhad, Iran
| | - Hamid Sadeghian
- Antimicrobial Resistance Research Center, Avicenna Research Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Laboratory Sciences, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran.
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573
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How to: molecular investigation of a hospital outbreak. Clin Microbiol Infect 2018; 25:688-695. [PMID: 30287413 DOI: 10.1016/j.cmi.2018.09.017] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2017] [Revised: 09/19/2018] [Accepted: 09/23/2018] [Indexed: 12/11/2022]
Abstract
BACKGROUND Studying hospital outbreaks by using molecular tools, i.e. synthesizing the molecular epidemiology data to its appropriate clinical-epidemiologic context, is crucial in order to identify infection source, infer transmission dynamics, appropriately allocate prevention resources and implement control measures. Whole-genome sequencing (WGS) of pathogens has become the reference standard, as it is becoming more accessible and affordable. Consequently, sequencing of the full pathogen genome via WGS and major progress in fit-for-purpose genomic data analysis tools and interpretation is revolutionizing the field of outbreak investigations in hospitals. Metagenomics is an additional evolving field that might become commonly used in the future for outbreak investigations. Nevertheless, practitioners are frequently limited in terms of WGS or metagenomics, especially for local outbreak analyses, as a result of costs or logistical considerations, reduced or lack of locally available resources and/or expertise. As a result, traditional approaches, including pulsed-field gel electrophoresis, repetitive-element palindromic PCR and multilocus sequence typing, along with other typing methods, are still widely used. AIMS To provide practitioners with evidenced-based action plans for usage of the various typing techniques in order to investigate the molecular epidemiology of nosocomial outbreaks, of clinically significant pathogens in acute-care hospitals. SOURCES PubMed search with relevant keywords along with personal collection of relevant publications. CONTENT Representative case scenarios and critical review of the relevant scientific literature. IMPLICATIONS The review provides practical action plans to manage molecular epidemiologic investigations of outbreaks caused by clinically significant nosocomial pathogens, while prioritizing the use and timely integration of the various methodologies.
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574
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Crépin S, Ottosen EN, Peters K, Smith SN, Himpsl SD, Vollmer W, Mobley HLT. The lytic transglycosylase MltB connects membrane homeostasis and in vivo fitness of Acinetobacter baumannii. Mol Microbiol 2018; 109:745-762. [PMID: 29884996 PMCID: PMC6185781 DOI: 10.1111/mmi.14000] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 05/30/2018] [Accepted: 07/15/2018] [Indexed: 01/06/2023]
Abstract
Acinetobacter baumannii has emerged as a leading nosocomial pathogen, infecting a wide range of anatomic sites including the respiratory tract and the bloodstream. In addition to being multi‐drug resistant, little is known about the molecular basis of A. baumannii pathogenesis. To better understand A. baumannii virulence, a combination of a transposon‐sequencing (TraDIS) screen and the neutropenic mouse model of bacteremia was used to identify the full set of fitness genes required during bloodstream infection. The lytic transglycosylase MltB was identified as a critical fitness factor. MltB cleaves the MurNAc‐GlcNAc bond of peptidoglycan, which leads to cell wall remodeling. Here we show that MltB is part of a complex network connecting resistance to stresses, membrane homeostasis, biogenesis of pili and in vivo fitness. Indeed, inactivation of mltB not only impaired resistance to serum complement, cationic antimicrobial peptides and oxygen species, but also altered the cell envelope integrity, activated the envelope stress response, drastically reduced the number of pili at the cell surface and finally, significantly decreased colonization of both the bloodstream and the respiratory tract.
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Affiliation(s)
- Sébastien Crépin
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Elizabeth N Ottosen
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Katharina Peters
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Sara N Smith
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Stephanie D Himpsl
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Waldemar Vollmer
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Harry L T Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, USA
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575
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Chapartegui-González I, Lázaro-Díez M, Bravo Z, Navas J, Icardo JM, Ramos-Vivas J. Acinetobacter baumannii maintains its virulence after long-time starvation. PLoS One 2018; 13:e0201961. [PMID: 30133491 PMCID: PMC6104976 DOI: 10.1371/journal.pone.0201961] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 07/25/2018] [Indexed: 12/12/2022] Open
Abstract
Acinetobacter baumannii is a cause of healthcare-associated infections. Although A. baumannii is an opportunistic pathogen, its infections are notoriously difficult to treat due to intrinsic and acquired antimicrobial resistance, often limiting effective therapeutic options. A. baumannii can survive for long periods in the hospital environment, particularly on inanimate surfaces. Such environments may act as a reservoir for cross-colonization and infection outbreaks and should be considered a substantial factor in infection control practices. Moreover, clothing of healthcare personnel and gadgets may play a role in the spread of nosocomial bacteria. A link between contamination of hospital surfaces and A. baumannii infections or between its persistence in the environment and its virulence has not yet been established. Bacteria under stress (i.e., long-term desiccation in hospital setting) could conserve factors that favor infection. To investigate whether desiccation and/or starvation may be involved in the ability of certain strains of A. baumannii to retain virulence factors, we have studied five well-characterized clinical isolates of A. baumannii for which survival times were determined under simulated hospital conditions. Despite a considerable reduction in the culturability over time (up to 88% depending on strain and the condition tested), some A. baumannii strains were able to maintain their ability to form biofilms after rehydration, addition of nutrients, and changing temperature. Also, after long-term desiccation, several clinical strains were able to grow in the presence of non-immune human serum as fine as their non-stressed homologs. Furthermore, we also show that the ability of bacterial strains to kill Galleria mellonella larvae does not change although A. baumannii cells were stressed by long-term starvation (up to 60 days). This means that A. baumannii can undergo a rapid adaptation to both the temperature shift and nutrients availability, conditions that can be easily found by bacteria in a new patient in the hospital setting.
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Affiliation(s)
- Itziar Chapartegui-González
- Instituto de Investigación Valdecilla IDIVAL, Santander, Spain
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| | - María Lázaro-Díez
- Instituto de Investigación Valdecilla IDIVAL, Santander, Spain
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain
| | - Zaloa Bravo
- Instituto de Investigación Valdecilla IDIVAL, Santander, Spain
| | - Jesús Navas
- Instituto de Investigación Valdecilla IDIVAL, Santander, Spain
- Departamento de Biología Molecular, Universidad de Cantabria, Santander, Spain
| | - José M. Icardo
- Departamento de Anatomía y Biología Celular, Universidad de Cantabria, Santander, Spain
| | - José Ramos-Vivas
- Instituto de Investigación Valdecilla IDIVAL, Santander, Spain
- Servicio de Microbiología, Hospital Universitario Marqués de Valdecilla, Santander, Spain
- Red Española de Investigación en Patología Infecciosa (REIPI), Instituto de Salud Carlos III, Madrid, Spain
- * E-mail:
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576
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Novović K, Mihajlović S, Dinić M, Malešević M, Miljković M, Kojić M, Jovčić B. Acinetobacter spp. porin Omp33-36: Classification and transcriptional response to carbapenems and host cells. PLoS One 2018; 13:e0201608. [PMID: 30071077 PMCID: PMC6072067 DOI: 10.1371/journal.pone.0201608] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Accepted: 07/18/2018] [Indexed: 01/11/2023] Open
Abstract
Acinetobacter baumannii has been recognized as one of the most challeging pathogens in clinical settings worldwide. Outer membrane porins play a significant role in Acinetobacter antibiotic resistance and virulence. A. baumannii carbapenem resistance and virulence factor porin Omp33-36 was the subject of this study. We investigated the omp33-36 gene transcriptional response in the growth phase, its response to carbapenems, and the effect of contact with host cells. Additionally, the cytotoxic effect of A. baumannii towards keratinocytes was assessed, as well as correlation between omp33-36 gene transcription and cytotoxicity. Further, Acinetobacter spp. Omp33-36 was classified and its characteristics relevant for vaccine candidature were determined. The level of the omp33-36 gene transcription varied between growth phases, but a common pattern could not be established among different strains. Treatment with subinhibitory concentrations of carbapenems decreased, while contact with keratinocytes increased omp33-36 expression in the analysed A. baumannii strains. Variations in omp33-36 mRNA levels did not correlate with cytotoxicity levels. Decrease of omp33-36 mRNA during treatment with subinhibitory concentrations of carbapenems, indicated the importance of transcriptional changes in reversible resistance to carbapenems due to the absence of Omp33-36. The transcription of omp33-36 increased after contact with keratinocytes, indicating the important role of de novo transcription during the initial phase of A. baumannii infection. Primary structural analysis of Acinetobacter spp. Omp33-36 revealed three distinct groups (among four A. baumannii variants). Although we have shown that Omp33-36 was highly polymorphic, we propose a potential antigen (PLAEAAFL motif) for vaccine development. According to PROVEAN analysis, the highly polymorphic structure of Omp33-36 porin should not influence its function significantly.
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Affiliation(s)
- Katarina Novović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Sanja Mihajlović
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Miroslav Dinić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Milka Malešević
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Marija Miljković
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Milan Kojić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | - Branko Jovčić
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
- Faculty of Biology, University of Belgrade, Belgrade, Serbia
- * E-mail:
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577
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Multidrug-Resistant Acinetobacter baumannii Chloramphenicol Resistance Requires an Inner Membrane Permease. Antimicrob Agents Chemother 2018; 62:AAC.00513-18. [PMID: 29891596 DOI: 10.1128/aac.00513-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/04/2018] [Indexed: 11/20/2022] Open
Abstract
Acinetobacter baumannii is a Gram-negative organism that is a cause of hospital-acquired multidrug-resistant (MDR) infections. A. baumannii has a unique cell surface compared to those of many other Gram-negative pathogens in that it can live without lipopolysaccharide (LPS) and it has a high content of cardiolipin in the outer membrane. Therefore, to better understand the cell envelope and mechanisms of MDR A. baumannii, we screened a transposon library for mutants with defective permeability barrier function, defined as a deficiency in the ability to exclude the phosphatase chromogenic substrate 5-bromo-4-chloro-3-indolylphosphate (XP). We identified multiple mutants with mutations in the ABUW_0982 gene, predicted to encode a permease broadly present in A. baumannii isolates with increased susceptibility to the ribosome-targeting antibiotic chloramphenicol (CHL). Moreover, compared to other known CHL resistance genes, such as chloramphenicol acyltransferase genes, we found that ABUW_0982 is the primary determinant of intrinsic CHL resistance in A. baumannii strain 5075 (Ab5075), an important isolate responsible for severe MDR infections in humans. Finally, studies measuring the efflux of chloramphenicol and expression of ABUW_0982 in CHL-susceptible Escherichia coli support the conclusion that ABUW_0982 encodes a single-component efflux protein with specificity for small, hydrophobic molecules, including CHL.
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578
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Gu H, Liu D, Zeng X, Peng LS, Yuan Y, Chen ZF, Zou QM, Shi Y. Aging exacerbates mortality of Acinetobacter baumannii pneumonia and reduces the efficacies of antibiotics and vaccine. Aging (Albany NY) 2018; 10:1597-1608. [PMID: 30018181 PMCID: PMC6075437 DOI: 10.18632/aging.101495] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 07/05/2018] [Indexed: 04/08/2023]
Abstract
Pneumonia caused by Acinetobacter baumannii has become a serious threat to the elderly. However, there are no experimental studies on the relevance between aging and A. baumannii infections. Here, we established an aged pneumonia mouse model by non-invasive intratracheal inoculation with A. baumannii. Higher mortality was observed in aged mice along with increased bacterial burdens and more severe lung injury. Increased inflammatory cell infiltration and enhanced pro-inflammatory cytokines at 24 hours post infection were detected in aged mice than those in young mice. Moreover, infected aged mice had lower myeloperoxidase levels in lungs and less reactive oxygen species-positive neutrophils in bronchoalveolar lavage fluid compared with infected young mice. Reduced efficacy of imipenem/cilastatin against A. baumannii was detected in aged mice. Vaccination of formalin-fixed A. baumannii provided 100% protection in young mice, whereas the efficacy of vaccine was completely diminished in aged mice. In conclusion, aging increased susceptibility to A. baumannii infection and impaired efficacies of antibiotics and vaccine. The aged mice model of A. baumannii pneumonia is a suitable model to study the effects of aging on A. baumannii infection and assess the efficacies of antibiotics and vaccines against A. baumannii for the elderly.
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Affiliation(s)
- Hao Gu
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, PR China
| | - Dong Liu
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, PR China
| | - Xi Zeng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, PR China
| | - Liu-Sheng Peng
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, PR China
| | - Yue Yuan
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, PR China
| | - Zhi-Fu Chen
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, PR China
| | - Quan-Ming Zou
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, PR China
| | - Yun Shi
- National Engineering Research Center of Immunological Products, Department of Microbiology and Biochemical Pharmacy, College of Pharmacy, Army Medical University, Chongqing 400038, PR China
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579
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Chen J, Yang Y, Xiang K, Li D, Liu H. Combined Rifampin and Sulbactam Therapy for Multidrug-Resistant Acinetobacter Baumannii Ventilator-Associated Pneumonia in Pediatric Patients. JOURNAL OF ANESTHESIA AND PERIOPERATIVE MEDICINE 2018; 5:176-185. [PMID: 31819924 PMCID: PMC6901084 DOI: 10.24015/japm.2018.0072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Background: With essentially no drug available to control the infection caused by the extensively drug-resistant Acinetobacter
baumannii (XDR-Ab) in infants and young children, this study explored the clinical outcomes of pediatric patients with
drug-resistant XDR-Ab who were treated with rifampicin in combination with sulbactam sodium. Methods: The data for clinical outcomes, microbiological responses, and side effects were collected and evaluated for 12
critically ill infants and young children diagnosed with ventilator-associated pneumonia caused by XDR-Ab following surgical
treatment for congenital heart disease in a pediatric cardiac intensive care unit. This study was approved by local
institutional review board (IRB). Results: Two patients died from the complex underlining diseases. The other 10 patients were weaned off the mechanical
ventilation successfully within 4–15 days after the start of treatment with rifampicin combined with sulbactam sodium
and discharged home. Three cases experienced adverse side effects, including severe rash and elevated aminotransferase
level. Conclusion: The combination of rifampicin and sulbactam sodium appeared to be an effective and safe therapy for severe
ventilator-associated pneumonia caused by XDR-Ab in infants and young children. Side effects such as skin rashes and elevated
aminotransferase levels can be reversed once rifampicin is discontinued in time. (Funded by the Department of Cardiovascular
Surgery, The Second Xiangya Hospital, Central South University, Changsha, China; the Departments of Anesthesiology and
Pain Medicine of University of California Davis Health; and the National Institutes of Health.)
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Affiliation(s)
- Jinlan Chen
- Department of Cardiovascular Surgery, The Second Xiangya Hospital, Central South University, Changsha, China.,Department of Anesthesiology and Pain Medicine, University of California Davis Health, Sacramento, CA, USA
| | - Yifeng Yang
- Department of Cardiovascular Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Kun Xiang
- Department of Cardiovascular Surgery, The Second Xiangya Hospital, Central South University, Changsha, China
| | - David Li
- Department of Anesthesiology and Pain Medicine, University of California Davis Health, Sacramento, CA, USA
| | - Hong Liu
- Department of Anesthesiology and Pain Medicine, University of California Davis Health, Sacramento, CA, USA
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580
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Nielsen TB, Yan J, Luna B, Spellberg B. Murine Oropharyngeal Aspiration Model of Ventilator-associated and Hospital-acquired Bacterial Pneumonia. J Vis Exp 2018. [PMID: 30010650 DOI: 10.3791/57672] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Murine infection models are critical for understanding disease pathogenesis and testing the efficacy of novel therapeutics designed to combat causative pathogens. Infectious pneumonia is among the most common infections presented by patients in the clinic and thus warrants an appropriate in vivo model. Typical pneumonia models use intranasal inoculation, which deposits excessive organisms outside the lung, causing off-target complications and symptoms, such as sinusitis, gastritis, enteritis, physical trauma, or microparticle misting to mimic aerosol spread more typical of viral, tuberculous, or fungal pneumonia. These models do not accurately reflect the pathogenesis of typical community- or healthcare-acquired bacterial pneumonia. In contrast, this murine model of oropharyngeal aspiration pneumonia mimics the droplet route in healthcare-acquired pneumonia. Inoculating 50 µL of the bacteria suspension into the oropharynx of anesthetized mice causes reflexive aspiration, which results in pneumonia. With this model, one can examine the pathogenesis of pneumonia-causing pathogens and new treatments to combat these diseases.
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Affiliation(s)
- Travis B Nielsen
- Department of Molecular Microbiology and Immunology, University of Southern California;
| | - Jun Yan
- Department of Molecular Microbiology and Immunology, University of Southern California
| | - Brian Luna
- Department of Molecular Microbiology and Immunology, University of Southern California
| | - Brad Spellberg
- Department of Molecular Microbiology and Immunology, University of Southern California; Division of Infectious Diseases, Department of Medicine, LAC+USC Medical Center
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581
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Correlation of Virulence Factors and Cell Adhesion of Clinical Isolates of Acinetobacter baumannii. ARCHIVES OF CLINICAL INFECTIOUS DISEASES 2018. [DOI: 10.5812/archcid.62841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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582
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Determinants of Mortality in Patients with Nosocomial Acinetobacter baumannii Bacteremia in Southwest China: A Five-Year Case-Control Study. CANADIAN JOURNAL OF INFECTIOUS DISEASES & MEDICAL MICROBIOLOGY 2018; 2018:3150965. [PMID: 29973964 PMCID: PMC6008754 DOI: 10.1155/2018/3150965] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 05/02/2018] [Accepted: 05/10/2018] [Indexed: 11/18/2022]
Abstract
Purpose This study was aimed to identify the determinants of in-hospital mortality in Acinetobacter baumannii (A. baumannii) bacteremia and to assess impact of carbapenem resistance on mortality. Methods A five-year case-control study was conducted from January 2011 to December 2015 in a tertiary teaching hospital with 3200 beds, Southwest China. Clinical outcomes and potential determinants of mortality in patients with nosocomial A. baumannii bacteremia and carbapenem-resistant A. baumannii (CRAB) bacteremia were evaluated using Cox and logistic regression analyses. Results A total of 118 patients with nosocomial A. baumannii bacteremia were included. Seventy-one percent (84/118) of them had carbapenem-resistant A. baumannii (CRAB) bacteremia. The in-hospital mortality of nosocomial A. baumannii bacteremia was 21.2%, and the attributable in-hospital mortality rate due to CRAB was 21.5%. Significant difference of 30-day in-hospital mortality in the Kaplan-Meier curves was found between CRAB and CSAB groups (log-rank test, P=0.025). The Cox regression analysis showed that patients with CRAB bacteremia had 2.72 times higher risk for 30-day in-hospital mortality than did those with carbapenem-susceptible A. baumannii (CSAB) bacteremia (95% confidence intervals (CIs) 1.14-6.61, P=0.016). The logistic regression analysis reported that mechanical ventilation and respiratory tract as origin of bacteremia were independent predictors of mortality among patients with nosocomial A. baumannii bacteremia and CRAB bacteremia, while high APACHE II score on the day of bacteremia and multiple organ dysfunction syndromes (MODS) during hospitalization were independent predictors of mortality among patients with nosocomial A. baumannii bacteremia but not CRAB bacteremia. Conclusion It was the severity of illness (high APACHE II score and MODS) not carbapenem resistance that highlighted the mortality of patients with nosocomial A. baumannii bacteremia. The impact of mechanical ventilation on mortality suggested that respiratory dysfunction might prime the poor outcome. Protection of respiratory function during the progression of nosocomial A. baumannii bacteremia should be given more importance. Early identification and intervention of patients with nosocomial A. baumannii bacteremia in critical ill conditions were advocated.
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583
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Kuti JL, Wang Q, Chen H, Li H, Wang H, Nicolau DP. Defining the potency of amikacin against Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii derived from Chinese hospitals using CLSI and inhalation-based breakpoints. Infect Drug Resist 2018; 11:783-790. [PMID: 29872328 PMCID: PMC5975598 DOI: 10.2147/idr.s161636] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVES We report the in vitro activity of amikacin and comparators against Gram-negative bacteria collected from blood and respiratory specimens in China during a 1-year period between December 2015 and December 2016. MATERIALS AND METHODS Minimum inhibitory concentrations (MICs) were determined by agar dilution methods using Clinical and Laboratory Standards Institute (CLSI) guidelines, and susceptibility was assessed using CLSI breakpoints, except for tigecycline against Enterobacteriaceae. A pharmacodynamic threshold MIC ≤ 256 mg/L was also applied for amikacin since its inhalation formulation has demonstrated activity up to these MICs. RESULTS For Escherichia coli, including extended-spectrum beta-lactamase (ESBL)-producing isolates (45.7% of population), amikacin demonstrated excellent activity (93.0%-94.7% susceptible) similar to tigecycline, piperacillin/tazobactam, and the carbapenems. Against Klebsiella pneumoniae, only tigecycline retained susceptibility >90%; amikacin inhibited 83.7% and 71.1% of the total and ESBL-producing (24.2%) populations at its breakpoint, respectively. Amikacin susceptibility against Pseudomonas aeruginosa was 91.1%, and only polymyxin B (100%) achieved higher susceptibility rates. Susceptibility declined to 80.9% and 54.5% against carbapenem- and multidrug-resistant (MDR) isolates, respectively. Finally, MDR was very common (84.0%) among Acinetobacter baumannii, with amikacin susceptibility at 30.5% for all isolates and 17.3% for MDR isolates. Since the majority of the amikacin-resistant isolates had amikacin MICs > 256 mg/L, the use of the inhalation pharmacodynamic threshold did not substantially improve the CLSI susceptible value. CONCLUSION Amikacin portrayed comparable or better susceptibility rates to most of the tested antibiotics against E. coli, K. pneumoniae, P. aeruginosa, and A. baumannii in China. As few isolates had MICs of 32-256 mg/L, use of the CLSI breakpoint and inhalation pharmacodynamic threshold yielded similar overall susceptibilities.
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Affiliation(s)
- Joseph L Kuti
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
| | - Qi Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Hongbin Chen
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Henan Li
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Hui Wang
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - David P Nicolau
- Center for Anti-Infective Research and Development, Hartford Hospital, Hartford, CT, USA
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584
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Comparison of Septic Shock Due to Multidrug-Resistant Acinetobacter baumannii or Klebsiella pneumoniae Carbapenemase-Producing K. pneumoniae in Intensive Care Unit Patients. Antimicrob Agents Chemother 2018; 62:AAC.02562-17. [PMID: 29555630 DOI: 10.1128/aac.02562-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/08/2018] [Indexed: 11/20/2022] Open
Abstract
A significant cause of mortality in the intensive care unit (ICU) is multidrug-resistant (MDR) Gram-negative bacteria, such as MDR Acinetobacter baumannii (MDR-AB) and Klebsiella pneumoniae carbapenemase-producing K. pneumoniae (KPC-Kp). The aim of the present study was to compare the clinical features, therapy, and outcome of patients who developed septic shock due to either MDR-AB or KPC-Kp. We retrospectively analyzed patients admitted to the ICU of a teaching hospital from November 2010 to December 2015 who developed septic shock due to MDR-AB or KPC-Kp infection. Data from 220 patients were analyzed: 128 patients (58.2%) were diagnosed with septic shock due to KPC-Kp, and 92 patients (41.8%) were diagnosed with septic shock due to MDR-AB. The 30-day mortality rate was significantly higher for the MDR-AB group than the KPC-Kp group (84.8% versus 44.5%, respectively; P < 0.001). Steroid exposure and pneumonia were associated with MDR-AB infection, whereas hospitalization in the previous 90 days, primary bacteremia, and KPC-Kp colonization were associated with KPC-Kp infection. For patients with KPC-Kp infections, the use of ≥2 in vitro-active antibiotics as empirical or definitive therapy was associated with higher 30-day survival, while isolation of colistin-resistant strains was linked to mortality. Patients with MDR-AB infections, age >60 years, and a simplified acute physiology score II (SAPS II) of >45 points were associated with increased mortality rates. We concluded that septic shock due to MDR-AB infection is associated with very high mortality rates compared to those with septic shock due to KPC-Kp. Analysis of the clinical features of these critically ill patients might help physicians in choosing appropriate empirical antimicrobial therapy.
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585
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Geisinger E, Mortman NJ, Vargas-Cuebas G, Tai AK, Isberg RR. A global regulatory system links virulence and antibiotic resistance to envelope homeostasis in Acinetobacter baumannii. PLoS Pathog 2018; 14:e1007030. [PMID: 29795704 PMCID: PMC5967708 DOI: 10.1371/journal.ppat.1007030] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 04/16/2018] [Indexed: 11/19/2022] Open
Abstract
The nosocomial pathogen Acinetobacter baumannii is a significant threat due to its ability to cause infections refractory to a broad range of antibiotic treatments. We show here that a highly conserved sensory-transduction system, BfmRS, mediates the coordinate development of both enhanced virulence and resistance in this microorganism. Hyperactive alleles of BfmRS conferred increased protection from serum complement killing and allowed lethal systemic disease in mice. BfmRS also augmented resistance and tolerance against an expansive set of antibiotics, including dramatic protection from β-lactam toxicity. Through transcriptome profiling, we showed that BfmRS governs these phenotypes through global transcriptional regulation of a post-exponential-phase-like program of gene expression, a key feature of which is modulation of envelope biogenesis and defense pathways. BfmRS activity defended against cell-wall lesions through both β-lactamase-dependent and -independent mechanisms, with the latter being connected to control of lytic transglycosylase production and proper coordination of morphogenesis and division. In addition, hypersensitivity of bfmRS knockouts could be suppressed by unlinked mutations restoring a short, rod cell morphology, indicating that regulation of drug resistance, pathogenicity, and envelope morphogenesis are intimately linked by this central regulatory system in A. baumannii. This work demonstrates that BfmRS controls a global regulatory network coupling cellular physiology to the ability to cause invasive, drug-resistant infections. Infections with the hospital-acquired bacterium Acinetobacter baumannii are highly difficult to treat. The pathogen has evolved multiple lines of defense against antimicrobial stress, including a barrier-forming cell envelope as well as control systems that respond to antimicrobial stresses by enhancing antibiotic resistance and virulence. Here, we uncovered the role of a key stress-response system, BfmRS, in controlling the transition of A. baumannii to a state of heightened resistance and virulence. We show that BfmRS enhances pathogenicity in mammalian hosts, and augments the ability to grow in the presence of diverse antibiotics and tolerate transient, high-level antibiotic exposures. Connected to these effects is the ability of BfmRS to globally reprogram gene expression and control multiple pathways that build, protect, and shape the cell envelope. Moreover, we determined that resistance-enhancing mutations bypassing the need for BfmRS also modulate envelope- and morphology-associated pathways, further linking control of physiology with resistance in A. baumannii. This work uncovers a global control circuit that shifts cellular physiology in ways that promote hospital-associated disease, and points to inhibition of this circuit as a potential strategy for disarming the pathogen.
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Affiliation(s)
- Edward Geisinger
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Nadav J. Mortman
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Germán Vargas-Cuebas
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Albert K. Tai
- Department of Integrative Physiology and Pathobiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
| | - Ralph R. Isberg
- Department of Molecular Biology and Microbiology, Tufts University School of Medicine, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- * E-mail:
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586
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Distribution of virulence-associated genes and antimicrobial susceptibility in clinical Acinetobacter baumannii isolates. Oncotarget 2018; 9:21663-21673. [PMID: 29774093 PMCID: PMC5955172 DOI: 10.18632/oncotarget.24651] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/26/2018] [Indexed: 12/15/2022] Open
Abstract
Acinetobacter baumannii is undoubtedly one of the most clinically significant pathogens. The multidrug resistance and virulence potential of A. baumannii are responsible for hospital-acquired nosocomial infections. Unlike numerous investigations on the drug-resistant epidemiology of A. baumanni, virulence molecular epidemiology is less studied. Here, we collected 88 A. baumannii clinical isolates, tested their antimicrobial susceptibility to 10 commonly used antibiotics and analyzed the distribution of 9 selected virulence-associated genes, aims to investigate the primary characteristics of the virulence-associated genes that exist in clinically multidrug resistant (MDR) and non-MDR isolates of A. baumannii. The MIC results showed the resistance rates of ciprofloxacin (68.2%, 60/88), gentamicin (67.0%, 59/88), amikacin (58.0%, 51/88), tobramycin (58.0%, 51/88), doxycycline (67.0%, 59/88), meropenem (54.5%, 48/88) and imipenem (65.9%, 58/88) were all above 50%, except for levofloxacin (34.1%, 30/88), minocycline (1.1%, 1/88) and polymyxin B (0%, 0/88). The Pulsed field gel electrophoresis (PFGE) analysis revealed that the resistance rate of MDR A. baumannii isolates in the Epidemic group was predominant (79.5%, 44/58), but in the Sporadic group was only 6.7% (2/30). Further investigation on the distribution of virulence genes showed the virulence genes bap (95.5%), surA1 (92.0%), BasD (92.0%), paaE (88.6%), pld (87.5%), BauA (62.5%), omp33-36 (59.1%) and pglC (53.4%) were accounted for high proportion, except for traT (0%). Overall, our results revealed that MDR isolates predominated in the Epidemic A. baumannii isolates, and contained a very high proportion of virulence genes, which may lead to high risk, high pathogenicity and high treatment challenge.
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587
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Dias MF, Reis MP, Acurcio LB, Carmo AO, Diamantino CF, Motta AM, Kalapothakis E, Nicoli JR, Nascimento AMA. Changes in mouse gut bacterial community in response to different types of drinking water. WATER RESEARCH 2018; 132:79-89. [PMID: 29306702 DOI: 10.1016/j.watres.2017.12.052] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 06/07/2023]
Abstract
Gut microbiota exerts a fundamental role on host physiology, and how extrinsic perturbations influence its composition has been increasingly examined. However, the effect of drinking water on gut microbiota is still poorly understood. In this study, we explored the response of mouse gut bacterial community (fecal and mucosa-adhered) to the ingestion of different types of drinking water. The experimental cohort was divided according to different water sources into four groups of mice that consumed autoclaved tap water (control group), water collected directly from a drinking water treatment plant, tap water, and commercial bottled mineral water. Differences among groups were observed, especially related to control group, which exhibited the smallest intra-group variation, and the largest distance from test groups on the last experimental day. Clinically important taxa, such as Acinetobacter and Staphylococcus, increased in feces of mice that drank tap water and in mucosa-adhered samples of animals from disinfected and tap water groups. Furthermore, statistical analyses showed that both time elapsed between samplings and water type significantly influenced the variation observed in the samples. Our results reveal that drinking water potentially affects gut microbiota composition. Additionally, the increase of typical drinking water clinically relevant and antibiotic resistance-associated bacteria in gut microbiota is a cause of concern.
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Affiliation(s)
- Marcela F Dias
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Mariana P Reis
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Leonardo B Acurcio
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Anderson O Carmo
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Cristiane F Diamantino
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Amanda M Motta
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Evanguedes Kalapothakis
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Jacques R Nicoli
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Andréa M A Nascimento
- Departamento de Biologia Geral, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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588
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Tang J, Zhu H, Cai L, Tang T, Tang J, Sun Y, Liu M, Dai K, Qiao Z, Yu C. Postoperative infection caused by Acinetobacter baumannii misdiagnosed as a free-living amoeba species in a humeral head hemiarthroplasty patient: a case report. Infect Dis Poverty 2018; 7:33. [PMID: 29631621 PMCID: PMC5890356 DOI: 10.1186/s40249-018-0408-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Accepted: 03/19/2018] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Acinetobacter baumannii is ubiquitous, facultative intracellular, and opportunistic bacterial pathogen. Its unique abilities allow it to survive in a diverse range of environments, including health care settings, leading to nosocomial infections. And its exceptional ability to develop resistance to multiple antibiotics leaves few drug options for treatment. It has been recognized as a leading cause of nosocomial pneumonia and bacteremia over the world. CASE PRESENTATION In this case, a 73-year-old woman presented with a Neer Group VI proximal humeral fracture. Six hours after a successfully performed hemiarthroplasty, she developed continuous fever. Clinical examination revealed that the vitals were regular. Laboratory and radiographic examinations revealed only elevated procalcitonin levels. Blood culture revealed no bacterial or fungal growth. Cooling treatment and empirical broad-spectrum antibiotic therapy showed no apparent effect. CONCLUSIONS We report a postoperative infection caused by Acinetobacter baumannii. The infectious pathogen was identified via molecular DNA sequencing and was initially misidentified as a free-living amoeba species upon microscopic examinations. The patient was mistreated with antiamebic combination therapy. Her symptoms persisted for over 4 months and were eventually followed by her death.
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Affiliation(s)
- Jiaxin Tang
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Huaimin Zhu
- Department of Microbiology and Parasitology, Second Military Medical University, Shanghai, 200433, China
| | - Li Cai
- Shanghai Municipal Center for Disease Control & Prevention, Shanghai, 200336, China
| | - Tingting Tang
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Jian Tang
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Yuehua Sun
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Ming Liu
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Kerong Dai
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China
| | - Zhiguang Qiao
- Medical 3D Printing Innovation Research Center, Shanghai Jiao Tong University School of Medicine, Shanghai, 200125, China. .,Engineering Research Center of Digital Medicine and Clinical Translation, Ministry of Education, Shanghai, 200030, China.
| | - Chao Yu
- Shanghai Key Laboratory of Orthopaedic Implants, Department of Orthopaedic Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China.
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589
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New Shuttle Vectors for Gene Cloning and Expression in Multidrug-Resistant Acinetobacter Species. Antimicrob Agents Chemother 2018; 62:AAC.02480-17. [PMID: 29339383 DOI: 10.1128/aac.02480-17] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/02/2018] [Indexed: 12/28/2022] Open
Abstract
Understanding bacterial pathogenesis requires adequate genetic tools to assess the role of individual virulence determinants by mutagenesis and complementation assays, as well as for homologous and heterologous expression of cloned genes. Our knowledge of Acinetobacter baumannii pathogenesis has so far been limited by the scarcity of genetic tools to manipulate multidrug-resistant (MDR) epidemic strains, which are responsible for most infections. Here, we report on the construction of new multipurpose shuttle plasmids, namely, pVRL1 and pVRL2, which can efficiently replicate in Acinetobacter spp. and in Escherichia coli The pVRL1 plasmid has been constructed by combining (i) the cryptic plasmid pWH1277 from Acinetobacter calcoaceticus, which provides an origin of replication for Acinetobacter spp.; (ii) a ColE1-like origin of replication; (iii) the gentamicin or zeocin resistance cassette for antibiotic selection; and (iv) a multilinker containing several unique restriction sites. Modification of pVRL1 led to the generation of the pVRL2 plasmid, which allows arabinose-inducible gene transcription with an undetectable basal expression level of cloned genes under uninduced conditions and a high dynamic range of responsiveness to the inducer. Both pVRL1 and pVRL2 can easily be selected in MDR A. baumannii, have a narrow host range and a high copy number, are stably maintained in Acinetobacter spp., and appear to be compatible with indigenous plasmids carried by epidemic strains. Plasmid maintenance is guaranteed by the presence of a toxin-antitoxin system, providing more insights into the mechanism of plasmid stability in Acinetobacter spp.
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590
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Combating Carbapenem-Resistant Acinetobacter baumannii by an Optimized Imipenem-plus-Tobramycin Dosage Regimen: Prospective Validation via Hollow-Fiber Infection and Mathematical Modeling. Antimicrob Agents Chemother 2018; 62:AAC.02053-17. [PMID: 29339388 DOI: 10.1128/aac.02053-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Accepted: 01/09/2018] [Indexed: 12/13/2022] Open
Abstract
We aimed to prospectively validate an optimized combination dosage regimen against a clinical carbapenem-resistant Acinetobacter baumannii (CRAB) isolate (imipenem MIC, 32 mg/liter; tobramycin MIC, 2 mg/liter). Imipenem at constant concentrations (7.6, 13.4, and 23.3 mg/liter, reflecting a range of clearances) was simulated in a 7-day hollow-fiber infection model (inoculum, ∼107.2 CFU/ml) with and without tobramycin (7 mg/kg q24h, 0.5-h infusions). While monotherapies achieved no killing or failed by 24 h, this rationally optimized combination achieved >5 log10 bacterial killing and suppressed resistance.
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591
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Logan LK, Gandra S, Trett A, Weinstein RA, Laxminarayan R. Acinetobacter baumannii Resistance Trends in Children in the United States, 1999-2012. J Pediatric Infect Dis Soc 2018; 8:136-142. [PMID: 29579216 PMCID: PMC6510944 DOI: 10.1093/jpids/piy018] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
BACKGROUND Acinetobacter baumannii is a common cause of healthcare-associated infections. Carbapenem-resistant (CR) A baumannii is a significant threat globally. We used a large reference laboratory database to study the epidemiology of A baumannii in children in the United States. METHODS Antimicrobial susceptibility data from The Surveillance Network were used to phenotypically identify antibiotic resistance in A baumannii isolates in children 1-17 years of age between January 1999 and July 2012. Logistic regression analysis was used to calculate trends in the prevalence of antibiotic resistance in A baumannii. Isolates from infants (<1 year old) were excluded. RESULTS The crude proportion of cephalosporin-resistant (CephR) A baumannii increased from 13.2% in 1999 to 23.4% in 2012 with a peak of 32.5% in 2008, and the proportion of CR A baumannii increased from 0.6% in 1999 to 6.1% in 2012 with a peak of 12.7% in 2008. From 1999 to 2012, the proportion of CephR and CR A baumannii increased each year by 3% and 8%, respectively (CephR odds ratio [OR] = 1.03, 95% confidence interval [CI], 1.01-1.04; CR OR = 1.08, 95% CI, 1.05-1.12); however, after 2008, a significant decrease in trend was observed (CephR OR = 0.78, 95% CI, 0.71-0.87; CR OR = 0.73, 95% CI, 0.62-0.86), but resistance remained higher than baseline (1999). CONCLUSIONS Overall, between 1999 and 2012, CephR and CR A baumannii isolates increased in children; however, a decreasing trend was observed after 2008.There is a need for ongoing surveillance of A baumannii infections and continued assessment of effective prevention strategies in vulnerable populations.
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Affiliation(s)
- Latania K Logan
- Department of Pediatrics, Division of Infectious Diseases, Rush Medical College, Rush University Medical Center, Chicago, Illinois,Section of Pediatric Infectious Diseases, Rush Medical College, Rush University Medical Center, Chicago, Illinois,Cook County Health and Hospitals System, Chicago, Illinois,Corresponding Author: L. K. Logan, MD, MSc, Department of Pediatrics, Section of Pediatric Infectious Diseases, Rush University Medical Center, 1620 West Harrison St., Suite 951 Jelke, Chicago, IL 60612. E-mail:
| | - Sumanth Gandra
- Center for Disease Dynamics, Economics & Policy, Washington, DC
| | - Anna Trett
- Center for Disease Dynamics, Economics & Policy, Washington, DC
| | - Robert A Weinstein
- Department of Internal Medicine, Division of Infectious Diseases, Rush Medical College, Rush University Medical Center, Chicago, Illinois,Cook County Health and Hospitals System, Chicago, Illinois
| | - Ramanan Laxminarayan
- Center for Disease Dynamics, Economics & Policy, Washington, DC,Princeton University, New Jersey
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592
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Elhosseiny NM, Attia AS. Acinetobacter: an emerging pathogen with a versatile secretome. Emerg Microbes Infect 2018; 7:33. [PMID: 29559620 PMCID: PMC5861075 DOI: 10.1038/s41426-018-0030-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 12/08/2017] [Accepted: 01/09/2018] [Indexed: 02/06/2023]
Abstract
Acinetobacter baumannii is a notorious pathogen that has emerged as a healthcare nightmare in recent years because it causes serious infections that are associated with high morbidity and mortality rates. Due to its exceptional ability to acquire resistance to almost all available antibiotics, A. baumannii is currently ranked as the first pathogen on the World Health Organization’s priority list for the development of new antibiotics. The versatile range of effectors secreted by A. baumannii represents a large proportion of the virulence arsenal identified in this bacterium to date. Thus, these factors, together with the secretory machinery responsible for their extrusion into the extracellular milieu, are key targets for novel therapeutics that are greatly needed to combat this deadly pathogen. In this review, we provide a comprehensive, up-to-date overview of the organization and regulatory aspects of the Acinetobacter secretion systems, with a special emphasis on their versatile substrates that could be targeted to fight the deadly infections caused by this elusive pathogen.
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Affiliation(s)
- Noha M Elhosseiny
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt
| | - Ahmed S Attia
- Department of Microbiology and Immunology, Faculty of Pharmacy, Cairo University, Cairo, 11562, Egypt.
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593
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A canine urinary tract infection representing the first clinical veterinary isolation of Acinetobacter ursingii. New Microbes New Infect 2018; 22:4-5. [PMID: 29556400 PMCID: PMC5857162 DOI: 10.1016/j.nmni.2017.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/23/2017] [Accepted: 11/24/2017] [Indexed: 11/24/2022] Open
Abstract
Acinetobacter species can be important opportunistic pathogens in humans, especially in healthcare settings. We report here the first isolation of Acinetobacter ursingii from an animal species; it was isolated from a canine urinary tract infection, and phenotypic identification proved unreliable.
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594
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Skariyachan S, Manjunath M, Bachappanavar N. Screening of potential lead molecules against prioritised targets of multi-drug-resistant-Acinetobacter baumannii - insights from molecular docking, molecular dynamic simulations and in vitro assays. J Biomol Struct Dyn 2018. [PMID: 29529934 DOI: 10.1080/07391102.2018.1451387] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Acinetobacter baumannii, an opportunistic pathogen, has become multi-drug resistant (MDR) to major classes of antibacterial and poses grave threat to public health. The current study focused to screen novel phytotherapeutics against prioritised targets of Acinetobacter baumannii by computational investigation. Fourteen potential drug targets were screened based on their functional role in various biosynthetic pathways and the 3D structures of 9 targets were retrieved from Protein Data Bank and others were computationally predicted. By extensive literature survey, 104 molecules from 48 herbal sources were screened and subjected to virtual screening. Ten clinical isolates of A. baumannii were tested for antibiotic susceptibility towards clinafloxacin, imipenem and polymyxin-E. Computational screening suggested that Ajmalicine ((19α)-16, 17-didehydro-19-methyloxayohimban-16-carboxylic acid methyl ester from Rauwolfia serpentina), Strictamin (Akuammilan-17-oic acid methyl ester from Alstonia scholaris) and Limonin (7, 16-dioxo-7, 16-dideoxylimondiol from Citrus sps) exhibited promising binding towards multiple drug targets of A. baumannii in comparison with the binding between standard drugs and their targets. Limonin displayed promising binding potential (binding energy -9.8 kcal/mol) towards diaminopimelate epimerase (DapF) and UDP-N-acetylglucosamine 1-carboxyvinyltransferase (MurA). Ajmalicine and Strictamin demonstrated good binding potential (-9.5, -8.5 kcal/mol, respectively) towards MurA and shikimate dehydrogenase (-7.8 kcal/mol). Molecular dynamic simulations further validated the docking results. In vitro assay suggested that the tested isolates exhibited resistance to clinafloxacin, imipenem and polymyxin-E and the herbal preparations (crude extract) demonstrated a significant antibacterial potential (p ≤ .05). The study suggests that the aforementioned lead candidates and targets can be used for structure-based drug screening towards MDR A. baumannii.
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Affiliation(s)
- Sinosh Skariyachan
- a Department of Biotechnology Engineering , Dayananda Sagar Institutions , Bengaluru 560 078 , Karnataka , India.,b Visvesvaraya Technological University , Belagavi , India
| | - Meghna Manjunath
- a Department of Biotechnology Engineering , Dayananda Sagar Institutions , Bengaluru 560 078 , Karnataka , India.,b Visvesvaraya Technological University , Belagavi , India
| | - Nikhil Bachappanavar
- a Department of Biotechnology Engineering , Dayananda Sagar Institutions , Bengaluru 560 078 , Karnataka , India.,b Visvesvaraya Technological University , Belagavi , India
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595
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Caselli E, Romagnoli C, Powers RA, Taracila MA, Bouza AA, Swanson HC, Smolen KA, Fini F, Wallar BJ, Bonomo RA, Prati F. Inhibition of Acinetobacter-Derived Cephalosporinase: Exploring the Carboxylate Recognition Site Using Novel β-Lactamase Inhibitors. ACS Infect Dis 2018; 4:337-348. [PMID: 29144725 DOI: 10.1021/acsinfecdis.7b00153] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Boronic acids are attracting a lot of attention as β-lactamase inhibitors, and in particular, compound S02030 ( Ki = 44 nM) proved to be a good lead compound against ADC-7 ( Acinetobacter-derived cephalosporinase), one of the most significant resistance determinants in A. baumannii. The atomic structure of the ADC-7/S02030 complex highlighted the importance of critical structural determinants for recognition of the boronic acids. Herein, to elucidate the role in recognition of the R2-carboxylate, which mimics the C3/C4 found in β-lactams, we designed, synthesized, and characterized six derivatives of S02030 (3a). Out of the six compounds, the best inhibitors proved to be those with an explicit negative charge (compounds 3a-c, 3h, and 3j, Ki = 44-115 nM), which is in contrast to the derivatives where the negative charge is omitted, such as the amide derivative 3d ( Ki = 224 nM) and the hydroxyamide derivative 3e ( Ki = 155 nM). To develop a structural characterization of inhibitor binding in the active site, the X-ray crystal structures of ADC-7 in a complex with compounds 3c, SM23, and EC04 were determined. All three compounds share the same structural features as in S02030 but only differ in the carboxy-R2 side chain, thereby providing the opportunity of exploring the distinct binding mode of the negatively charged R2 side chain. This cephalosporinase demonstrates a high degree of versatility in recognition, employing different residues to directly interact with the carboxylate, thus suggesting the existence of a "carboxylate binding region" rather than a binding site in ADC enzymes. Furthermore, this class of compounds was tested against resistant clinical strains of A. baumannii and are effective at inhibiting bacterial growth in conjunction with a β-lactam antibiotic.
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Affiliation(s)
- Emilia Caselli
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 101, 41125, Modena, Italy
| | - Chiara Romagnoli
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 101, 41125, Modena, Italy
| | - Rachel A. Powers
- Department of Chemistry, Grand Valley State University, 1 Campus Drive, Allendale, Michigan 49401, United States
| | - Magdalena A. Taracila
- Departments of Medicine, Pharmacology, Biochemistry and Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Alexandra A. Bouza
- Department of Chemistry, Grand Valley State University, 1 Campus Drive, Allendale, Michigan 49401, United States
| | - Hollister C. Swanson
- Department of Chemistry, Grand Valley State University, 1 Campus Drive, Allendale, Michigan 49401, United States
| | - Kali A. Smolen
- Department of Chemistry, Grand Valley State University, 1 Campus Drive, Allendale, Michigan 49401, United States
| | - Francesco Fini
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 101, 41125, Modena, Italy
| | - Bradley J. Wallar
- Department of Chemistry, Grand Valley State University, 1 Campus Drive, Allendale, Michigan 49401, United States
| | - Robert A. Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs
Medical Center, 10701 East Boulevard, Cleveland, Ohio 44106, United States
- Departments of Medicine, Pharmacology, Biochemistry and Molecular Biology and Microbiology, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106, United States
| | - Fabio Prati
- Department of Life Sciences, University of Modena and Reggio Emilia, Via Campi 101, 41125, Modena, Italy
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596
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Jeon H, Kim S, Kim MH, Kim SY, Nam D, Park SC, Park SH, Bae H, Lee HJ, Cho JH, Lee WK, Lee YC, Lee SH, Shin MS, Lee JC. Molecular epidemiology of carbapenem-resistant Acinetobacter baumannii isolates from a Korean hospital that carry blaOXA-23. INFECTION GENETICS AND EVOLUTION 2018; 58:232-236. [DOI: 10.1016/j.meegid.2018.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/20/2017] [Accepted: 01/04/2018] [Indexed: 10/18/2022]
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597
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Evidence to improve the treatment of infections caused by carbapenem-resistant Gram-negative bacteria. THE LANCET. INFECTIOUS DISEASES 2018; 18:358-360. [PMID: 29456042 DOI: 10.1016/s1473-3099(18)30112-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 01/03/2018] [Indexed: 11/21/2022]
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598
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Kamoshida G, Kikuchi-Ueda T, Nishida S, Tansho-Nagakawa S, Ubagai T, Ono Y. Pathogenic Bacterium Acinetobacter baumannii Inhibits the Formation of Neutrophil Extracellular Traps by Suppressing Neutrophil Adhesion. Front Immunol 2018; 9:178. [PMID: 29467765 PMCID: PMC5808340 DOI: 10.3389/fimmu.2018.00178] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 01/19/2018] [Indexed: 12/12/2022] Open
Abstract
Hospital-acquired infections caused by Acinetobacter baumannii have become problematic because of high rates of drug resistance. A. baumannii is usually harmless, but it may cause infectious diseases in an immunocompromised host. Although neutrophils are the key players of the initial immune response against bacterial infection, their interactions with A. baumannii remain largely unknown. A new biological defense mechanism, termed neutrophil extracellular traps (NETs), has been attracting attention. NETs play a critical role in bacterial killing by bacterial trapping and inactivation. Many pathogenic bacteria have been reported to induce NET formation, while an inhibitory effect on NET formation is rarely reported. In the present study, to assess the inhibition of NET formation by A. baumannii, bacteria and human neutrophils were cocultured in the presence of phorbol 12-myristate 13-acetate (PMA), and NET formation was evaluated. NETs were rarely observed during the coculture despite neutrophil PMA stimulation. Furthermore, A. baumannii prolonged the lifespan of neutrophils by inhibiting NET formation. The inhibition of NET formation by other bacteria was also investigated. The inhibitory effect was only apparent with live A. baumannii cells. Finally, to elucidate the mechanism of this inhibition, neutrophil adhesion was examined. A. baumannii suppressed the adhesion ability of neutrophils, thereby inhibiting PMA-induced NET formation. This suppression of cell adhesion was partly due to suppression of the surface expression of CD11a in neutrophils. The current study constitutes the first report on the inhibition of NET formation by a pathogenic bacterium, A. baumannii, and prolonging the neutrophil lifespan. This novel pathogenicity to inhibit NET formation, thereby escaping host immune responses might contribute to a development of new treatment strategies for A. baumannii infections.
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Affiliation(s)
- Go Kamoshida
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, 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
| | - 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
| | - Yasuo Ono
- Department of Microbiology and Immunology, School of Medicine, Teikyo University, Tokyo, Japan
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599
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El Chakhtoura NG, Saade E, Iovleva A, Yasmin M, Wilson B, Perez F, Bonomo RA. Therapies for multidrug resistant and extensively drug-resistant non-fermenting gram-negative bacteria causing nosocomial infections: a perilous journey toward 'molecularly targeted' therapy. Expert Rev Anti Infect Ther 2018; 16:89-110. [PMID: 29310479 PMCID: PMC6093184 DOI: 10.1080/14787210.2018.1425139] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 01/04/2018] [Indexed: 12/30/2022]
Abstract
INTRODUCTION Non-fermenting Gram-negative bacilli are at the center of the antimicrobial resistance epidemic. Acinetobacter baumannii and Pseudomonas aeruginosa are both designated with a threat level to human health of 'serious' by the Centers for Disease Control and Prevention. Two other major non-fermenting Gram-negative bacilli, Stenotrophomonas maltophilia and Burkholderia cepacia complex, while not as prevalent, have devastating effects on vulnerable populations, such as those with cystic fibrosis, as well as immunosuppressed or hospitalized patients. Areas covered: In this review, we summarize the clinical impact, presentations, and mechanisms of resistance of these four major groups of non-fermenting Gram-negative bacilli. We also describe available and promising novel therapeutic options and strategies, particularly combination antibiotic strategies, with a focus on multidrug resistant variants. Expert commentary: We finally advocate for a therapeutic approach that incorporates in vitro antibiotic susceptibility testing with molecular and genotypic characterization of mechanisms of resistance, as well as pharmacokinetics and pharmacodynamics (PK/PD) parameters. The goal is to begin to formulate a precision medicine approach to antimicrobial therapy: a clinical-decision making model that integrates bacterial phenotype, genotype and patient's PK/PD to arrive at rationally-optimized combination antibiotic chemotherapy regimens tailored to individual clinical scenarios.
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Affiliation(s)
- Nadim G. El Chakhtoura
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Elie Saade
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Medicine, University Hospitals Cleveland Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Alina Iovleva
- Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, PA
| | - Mohamad Yasmin
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Medicine, University Hospitals Cleveland Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Brigid Wilson
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Federico Perez
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Robert A. Bonomo
- Medicine Case Western Reserve University School of Medicine, Cleveland, Ohio
- Research Services Case Western Reserve University School of Medicine, Cleveland, Ohio
- Geriatrics Research, Education and Clinical Center, Louis Stokes Cleveland Department of Veterans Affairs Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
- Department of Medicine, University Hospitals Cleveland Medical Center Case Western Reserve University School of Medicine, Cleveland, Ohio
- Departments of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio
- Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio
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600
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Cameranesi MM, Morán-Barrio J, Limansky AS, Repizo GD, Viale AM. Site-Specific Recombination at XerC/D Sites Mediates the Formation and Resolution of Plasmid Co-integrates Carrying a blaOXA-58- and Tn aphA6-Resistance Module in Acinetobacter baumannii. Front Microbiol 2018; 9:66. [PMID: 29434581 PMCID: PMC5790767 DOI: 10.3389/fmicb.2018.00066] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 01/11/2018] [Indexed: 12/21/2022] Open
Abstract
Members of the genus Acinetobacter possess distinct plasmid types which provide effective platforms for the acquisition, evolution, and dissemination of antimicrobial resistance structures. Many plasmid-borne resistance structures are bordered by short DNA sequences providing potential recognition sites for the host XerC and XerD site-specific tyrosine recombinases (XerC/D-like sites). However, whether these sites are active in recombination and how they assist the mobilization of associated resistance structures is still poorly understood. Here we characterized the plasmids carried by Acinetobacter baumannii Ab242, a multidrug-resistant clinical strain belonging to the ST104 (Oxford scheme) which produces an OXA-58 carbapenem-hydrolyzing class-D β-lactamase (CHDL). Plasmid sequencing and characterization of replication, stability, and adaptive modules revealed the presence in Ab242 of three novel plasmids lacking self-transferability functions which were designated pAb242_9, pAb242_12, and pAb242_25, respectively. Among them, only pAb242_25 was found to carry an adaptive module encompassing an ISAba825-blaOXA-58 arrangement accompanied by a TnaphA6 transposon, the whole structure conferring simultaneous resistance to carbapenems and aminoglycosides. Ab242 plasmids harbor several XerC/D-like sites, with most sites found in pAb242_25 located in the vicinity or within the adaptive module described above. Electrotransformation of susceptible A. nosocomialis cells with Ab242 plasmids followed by imipenem selection indicated that the transforming plasmid form was a co-integrate resulting from the fusion of pAb242_25 and pAb242_12. Further characterization by cloning and sequencing studies indicated that a XerC/D site in pAb242_25 and another in pAb242_12 provided the active sister pair for the inter-molecular site-specific recombination reaction mediating the fusion of these two plasmids. Moreover, the resulting co-integrate was found also to undergo intra-molecular resolution at the new pair of XerC/D sites generated during fusion thus regenerating the original pAb242_25 and pAb242_12 plasmids. These observations provide the first evidence indicating that XerC/D-like sites in A. baumannii plasmids can provide active pairs for site-specific recombination mediating inter-molecular fusions and intra-molecular resolutions. The overall results shed light on the evolutionary dynamics of A. baumannii plasmids and the underlying mechanisms of dissemination of genetic structures responsible for carbapenem and other antibiotics resistance among the Acinetobacter clinical population.
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Affiliation(s)
- María M Cameranesi
- Instituto de Biología Molecular y Celular de Rosario (IBR), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Jorgelina Morán-Barrio
- Instituto de Biología Molecular y Celular de Rosario (IBR), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Adriana S Limansky
- Instituto de Biología Molecular y Celular de Rosario (IBR), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Guillermo D Repizo
- Instituto de Biología Molecular y Celular de Rosario (IBR), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Universidad Nacional de Rosario (UNR), Rosario, Argentina
| | - Alejandro M Viale
- Instituto de Biología Molecular y Celular de Rosario (IBR), Departamento de Microbiología, Facultad de Ciencias Bioquímicas y Farmacéuticas, CONICET, Universidad Nacional de Rosario (UNR), Rosario, Argentina
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