scholarly journals In Vitro Evaluation of Antimicrobial Peptide Tridecaptin M in Combination with Other Antibiotics against Multidrug Resistant Acinetobacter baumannii

Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3255
Author(s):  
Manoj Jangra ◽  
Vrushali Raka ◽  
Hemraj Nandanwar
Keyword(s):  
Antimicrobial Peptide ◽  
Acinetobacter Baumannii ◽  
Ex Vivo ◽  
Combined Treatment ◽  
Antimicrobial Effect ◽  
Concomitant Administration ◽  
Multidrug Resistant ◽  
Infection Model ◽  
Permeability Barrier

The rapid emergence of antimicrobial resistance in Acinetobacter baumannii coupled with the dried pipeline of novel treatments has driven the search for new therapeutic modalities. Gram-negative bacteria have an extra outer membrane that serves as a permeability barrier for various hydrophobic and/or large compounds. One of the popular approaches to tackle this penetration barrier is use of potentiators or adjuvants in combination with traditional antibiotics. This study reports the in vitro potential of an antimicrobial peptide tridecaptin M in combination with other antibiotics against different strains of A. baumannii. Tridecaptin M sensitized the bacteria to rifampicin, vancomycin, and ceftazidime. Further, we observed that a tridecaptin M and rifampicin combination killed the bacteria completely in 4 h in an ex vivo blood infection model and was superior to rifampicin monotherapy. The study also found that concomitant administration of both compounds is not necessary to achieve the antimicrobial effect. Bacteria pre-treated with tridecaptin M (for 2–4 h) followed by exposure to rifampicin showed similar killing as obtained for combined treatment. Additionally, this combination hampered the survival of persister development in comparison to rifampicin alone. These findings encourage the future investigation of this combination to treat severe infections caused by extremely drug-resistant A. baumannii.

scholarly journals Catechol cross-linked antimicrobial peptide hydrogels prevent multidrug-resistant Acinetobacter baumannii infection in burn wounds

2019 ◽  
Vol 39 (6) ◽  
Author(s):  
Abidullah Khan ◽  
Miao Xu ◽  
Tengjiao Wang ◽  
Chuangang You ◽  
Xingang Wang ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Acinetobacter Baumannii ◽  
Bacterial Infections ◽  
Skin Surface ◽  
Multidrug Resistant ◽  
Burn Wound ◽  
Burn Wounds ◽  
Myoblast Cell Line ◽  
Myoblast Cell

Abstract Hospital-acquired infections are common in burn patients and are the major contributors of morbidity and mortality. Bacterial infections such as Staphylococcus aureus (S. aureus) and Acinetobacter baumannii (A. baumannii) are difficult to treat due to their biofilm formation and rapidly acquiring resistance to antibiotics. This work presents a newly developed hydrogel that has the potential for treating bacterial wound infections. The hydrogel formulation is based on an antimicrobial peptide (AMP), epsilon-poly-l-lysine (EPL) and catechol, which was cross-linked via mussel-inspired chemistry between the amine and phenol groups. In vitro studies showed that EPL-catechol hydrogels possess impressive antimicrobial and antibiofilm properties toward multidrug-resistant A. baumannii (MRAB). In addition, cytotoxicity study with the clonal mouse myoblast cell line (C2C12) revealed the good biocompatibility of this hydrogel. Furthermore, we created a second-degree burn wound on the mice dorsal skin surface followed by contamination with MRAB. Our results showed that the hydrogel significantly reduced the bacterial burden by more than four orders of magnitude in infected burn wounds. Additionally, there was no significant histological alteration with hydrogel application on mice skin. Based on these results, we concluded that EPL-catechol hydrogel is a promising future biomaterial to fight against multidrug-resistant bacterial infections.

scholarly journals The K1 Capsular Polysaccharide of Acinetobacter baumannii Strain 307-0294 Is a Major Virulence Factor

2010 ◽  
Vol 78 (9) ◽  
pp. 3993-4000 ◽  
Author(s):  
Thomas A. Russo ◽  
Nicole R. Luke ◽  
Janet M. Beanan ◽  
Ruth Olson ◽  
Shauna L. Sauberan ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Drug Targets ◽  
Protein Tyrosine Kinase ◽  
Capsular Polysaccharide ◽  
Multidrug Resistant ◽  
Ascites Fluid ◽  
Infection Model ◽  
Flow Cytometric ◽  
K1 Capsule

ABSTRACT Acinetobacter baumannii is a pathogen of increasing medical importance with a propensity to be multidrug resistant, thereby making treatment challenging. Little is known of virulence traits in A. baumannii. To identify virulence factors and potential drug targets, random transposon (Tn) mutants derived from the A. baumannii strain AB307-0294 were screened to identify genes essential for growth in human ascites fluid in vitro, an inflammatory exudative fluid. These studies led to the identification of two genes that were predicted to be required for capsule polymerization and assembly. The first, ptk, encodes a putative protein tyrosine kinase (PTK), and the second, epsA, encodes a putative polysaccharide export outer membrane protein (EpsA). Monoclonal antibodies used in flow cytometric and Western analyses confirmed that these genes are required for a capsule-positive phenotype. A capsule-positive phenotype significantly optimized growth in human ascites fluid, survival in human serum, and survival in a rat soft tissue infection model. Importantly, the clearance of the capsule-minus mutants AB307.30 (ptk mutant, capsule minus) and AB307.45 (epsA mutant, capsule minus) was complete and durable. These data demonstrated that the K1 capsule from AB307-0294 was an important protectin. Further, these data suggested that conserved proteins, which contribute to the capsule-positive phenotype, are potential antivirulence drug targets. Therefore, the results from this study have important biologic and translational implications and, to the best of our knowledge, are the first to address the role of capsule in the pathogenesis of A. baumannii infection.

scholarly journals A Potential Combination Therapy of Berberine Hydrochloride With Antibiotics Against Multidrug-Resistant Acinetobacter baumannii

2021 ◽  
Vol 11 ◽  
Author(s):  
Xiaobo Li ◽  
Yanqing Song ◽  
Lina Wang ◽  
Guangbo Kang ◽  
Ping Wang ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Synergistic Effects ◽  
Multidrug Resistant ◽  
Infection Model ◽  
Berberine Hydrochloride ◽  
Transporter Protein ◽  
Antimicrobial Efficiency ◽  
Global Threat

Multidrug-resistant (MDR) Acinetobacter baumannii strains can cause severe infections in intensive care units, and are rapidly developing resistance to the last-resort of existing antibiotics, posing a major global threat to health care system. Berberine hydrochloride (BBH), a kind of isoquinoline alkaloids extracted from Berberis and other plants, has been widely used as an antibacterial medicine for its reliable therapeutic efficiency. The in vitro synergistic effects of BBH with antibiotics against MDR A. baumannii were determined. BBH alone had weak antimicrobial activity (e.g., MIC≥256 mg/L) against MDR A. baumannii. However, it dramatically increased the susceptibility of MDR strains against antibiotics with FICI values <0.5, even reversed their resistance to antibiotics (e.g., tigecycline, sulbactam, meropenem and ciprofloxacin). In vivo study has suggested BBH with sulbactam had stronger antimicrobial efficiency than monotherapy in a neutropenic murine thigh infection model. The antibiotic-sensitizing mechanism of action of BBH was evaluated as well. BBH boosted adeB gene expression and bound to the AdeB transporter protein, resulting in low uptake of BBH, which may contribute to less extrusion of antibiotics by the AdeABC pump. Knockout of the adeB gene increased uptake of BBH and diminished the antibiotic sensitization and synergistic effects between antibiotics and BBH in MDR strains. Together, BBH effectively re-sensitizes this MDR pathogen to a range of antibiotics that have become barely effective due to antibiotic resistance, which indicates BBH may be a promising therapeutic adjuvant candidate to combat MDR A. baumannii.

Humanized Exposures of a β-Lactam-β-Lactamase Inhibitor, Tazobactam, versus Non-β-Lactam-β-Lactamase Inhibitor, Avibactam, with or without Colistin, against Acinetobacter baumannii in Murine Thigh and Lung Infection Models

Pharmacology ◽  
2018 ◽  
Vol 101 (5-6) ◽  
pp. 255-261 ◽  
Author(s):  
Marguerite L. Monogue ◽  
George Sakoulas ◽  
Victor Nizet ◽  
David P. Nicolau
Keyword(s):  
Acinetobacter Baumannii ◽  
Lung Infection ◽  
Multidrug Resistant ◽  
Lung Model ◽  
Infection Model ◽  
Peptide Antibiotics ◽  
Infection Models ◽  
Lactamase Inhibitor

β-lactam-β-lactamase inhibitors (BLIs) have previously demonstrated antimicrobial activity against Acinetobacter baumannii (AB). Colistin retains the highest susceptibility rate against A. baumannii, and has demonstrated synergy with other antimicrobials, including β-lactam-BLIs. Therefore, we assessed the potential individual activity and synergistic combinations in vivo against carbapenem-susceptible (CS) and multidrug-resistant (MDR) A. baumannii isolates in neutropenic thigh and lung infection models. In vitro, colistin and tazobactam MICs were 1 and 16 µg/mL against AB 25–49 (CS) and 1 and 128 µg/mL against AB 5075 (MDR) respectively. In the lung model, tazobactam alone and in combination with colistin achieved a 1-log reduction in CFU, while colistin alone was not active against AB 25–49. No activity was observed against AB 5075. In the thigh model, tazobactam with and without colistin was bacteriostatic against AB 25–49 but did not demonstrate any activity against AB 5075. Avibactam and colistin alone and in combination were not active against either isolate. No synergy was observed; however, we found tazobactam activity against A. baumannii. This activity was not observed for the non-β-lactam-BLI, avibactam. This suggests that binding to penicillin-binding proteins of the β-lactam molecule is required for tazobactam activity against A. baumannii. These data point to an added role of β-lactam-BLIs beyond their primary purpose of β-lactamase inhibition in the treatment of MDR A. baumannii infections by enhancing the activity of peptide antibiotics, a property that is not shared by the novel non-β-lactam-BLIs. Future studies are needed to define tazobactam and colistin activity in an A. baumannii infection model.

scholarly journals Efficacy of Rifampin and Its Combinations with Imipenem, Sulbactam, and Colistin in Experimental Models of Infection Caused by Imipenem-Resistant Acinetobacter baumannii

2010 ◽  
Vol 54 (3) ◽  
pp. 1165-1172 ◽  
Author(s):  
María E. Pachón-Ibáñez ◽  
Fernando Docobo-Pérez ◽  
Rafael López-Rojas ◽  
Juan Domínguez-Herrera ◽  
Manuel E. Jiménez-Mejias ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Combined Treatment ◽  
Multidrug Resistant ◽  
Experimental Models ◽  
Blood Cultures ◽  
Control Group ◽  
Group I ◽  
Time Kill ◽  
Bacterial Concentrations

ABSTRACT There are currently no defined optimal therapies available for multidrug-resistant (MDR) Acinetobacter baumannii infections. We evaluated the efficacy of rifampin, imipenem, sulbactam, colistin, and their combinations against MDR A. baumannii in experimental pneumonia and meningitis models. The bactericidal in vitro activities of rifampin, imipenem, sulbactam, colistin, and their combinations were tested using time-kill curves. Murine pneumonia and rabbit meningitis models were evaluated using the A. baummnnii strain Ab1327 (with MICs for rifampin, imipenem, sulbactam, and colistin of 4, 32, 32, and 0.5 mg/liter, respectively). Mice were treated with the four antimicrobials and their combinations. For the meningitis model, the efficacies of colistin, rifampin and its combinations with imipenem, sulbactam, or colistin, and of imipenem plus sulbactam were assayed. In the pneumonia model, compared to the control group, (i) rifampin alone, (ii) rifampin along with imipenem, sulbactam, or colistin, (iii) colistin, or (iv) imipenem plus sulbactam significantly reduced lung bacterial concentrations (10.6 ± 0.27 [controls] versus 3.05 ± 1.91, 2.07 ± 1.82, 2.41 ± 1.37, 3.4 ± 3.07, 6.82 ± 3.4, and 4.22 ± 2.72 log10 CFU/g, respectively [means ± standard deviations]), increased sterile blood cultures (0% versus 78.6%, 100%, 93.3%, 93.8%, 73.3%, and 50%), and improved survival (0% versus 71.4%, 60%, 46.7%, 43.8%, 40%, and 85.7%). In the meningitis model rifampin alone or rifampin plus colistin reduced cerebrospinal fluid bacterial counts (−2.6 and −4.4 log10 CFU/ml). Rifampin in monotherapy or with imipenem, sulbactam, or colistin showed efficacy against MDR A. baumannii in experimental models of pneumonia and meningitis. Imipenem or sulbactam may be appropriate for combined treatment when using rifampin.

scholarly journals In VitroActivity of the Novel Antimicrobial Peptide Dendrimer G3KL against Multidrug-Resistant Acinetobacter baumannii and Pseudomonas aeruginosa

2015 ◽  
Vol 59 (12) ◽  
pp. 7915-7918 ◽  
Author(s):  
João Pires ◽  
Thissa N. Siriwardena ◽  
Michaela Stach ◽  
Regula Tinguely ◽  
Sara Kasraian ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antimicrobial Peptide ◽  
Acinetobacter Baumannii ◽  
Multidrug Resistant ◽  
Drug Resistant ◽  
The Novel ◽  
Content Type ◽  
Extensively Drug Resistant ◽  
Peptide Dendrimer

ABSTRACTThein vitroactivity of the novel antimicrobial peptide dendrimer G3KL was evaluated against 32Acinetobacter baumannii(including 10 OXA-23, 7 OXA-24, and 11 OXA-58 carbapenemase producers) and 35Pseudomonas aeruginosa(including 18 VIM and 3 IMP carbapenemase producers) strains and compared to the activities of standard antibiotics. Overall, both species collections showed MIC50/90values of 8/8 μg/ml and minimum bactericidal concentrations at which 50% or 90% of strains tested are killed (MBC50/90) of 8/8 μg/ml. G3KL is a promising molecule with antibacterial activity against multidrug-resistant and extensively drug-resistantA. baumanniiandP. aeruginosaisolates.

In Vitro, In Silico and Ex Vivo Studies of Dihydroartemisinin Derivatives as Antitubercular Agents

2019 ◽  
Vol 19 (8) ◽  
pp. 633-644 ◽  
Author(s):  
Komal Kalani ◽  
Sarfaraz Alam ◽  
Vinita Chaturvedi ◽  
Shyam Singh ◽  
Feroz Khan ◽  
...  
Keyword(s):  
Bone Marrow ◽  
In Silico ◽  
Ex Vivo ◽  
Virulent Strain ◽  
Infection Model ◽  
Mouse Bone Marrow ◽  
Significant Activity ◽  
Macrophage Infection ◽  
In Silico Studies

Introduction: As a part of our drug discovery program for anti-tubercular agents, dihydroartemisinin (DHA-1) was screened against Mtb H37Rv, which showed moderate anti-tubercular activity (>25.0 µg/mL). These results prompted us to carry out the chemical transformation of DHA-1 into various derivatives and study their antitubercular potential. Materials and Methods: DHA-1 was semi-synthetically converted into four new acyl derivatives (DHA-1A – DHA-1D) and in-vitro evaluated for their anti-tubercular potential against Mycobacterium tuberculosis H37Rv virulent strain. The derivatives, DHA-1C (12-O-(4-nitro) benzoyl; MIC 12.5 µg/mL) and DHA-1D (12-O-chloro acetyl; MIC 3.12µg/mL) showed significant activity against the pathogen. Results: In silico studies of the most active derivative (DHA-1D) showed interaction with ARG448 inhibiting the mycobacterium enzymes. Additionally, it showed no cytotoxicity towards the Vero C1008 cells and Mouse bone marrow derived macrophages. Conclusion: DHA-1D killed 62% intracellular M. tuberculosis in Mouse bone marrow macrophage infection model. To the best of our knowledge, this is the first-ever report on the antitubercular potential of dihydroartemisinin and its derivatives. Since dihydroartemisinin is widely used as an antimalarial drug; these results may be of great help in anti-tubercular drug development from a very common, inexpensive, and non-toxic natural product.

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