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Hadiya S, Ibrahem RA, Abd El-Baky RM, Elsabahy M, Hussein AM, Tolba ME, Aly SA. Nano-ciprofloxacin/meropenem exhibit bactericidal activity against Gram-negative bacteria and rescue septic rat model. Nanomedicine (Lond) 2023; 18:1553-1566. [PMID: 37933674 DOI: 10.2217/nnm-2022-0314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2023] Open
Abstract
Aim: We hypothesized that simultaneous administration of two antibiotics loaded into a nanopolymer matrix would augment their synergistic bactericidal interaction. Methods: Nanoplatforms of chitosan/Pluronic® loaded with ciprofloxacin/meropenem (CS/Plu-Cip/Mer) were prepared by the ionic gelation method, using Plu at concentrations in the range 0.5-4% w/v. CS/Plu-Cip/Mer was evaluated for antibacterial synergistic activity in vitro and in vivo. Results: CS/Plu-Cip and CS/Plu-Mer with Plu concentrations of 3% w/v and 2% w/v, respectively, exhibited ∼80% encapsulation efficiency. The MICs of pathogens were fourfold to 16-fold lower for CS/Plu-Cip/Mer than for Cip/Mer. Synergy was evidenced for CS/Plu-Cip/Mer with a bactericidal effect (at 1× MIC and sub-MICs), and it significantly decreased bacterial load and rescued infected rats. Conclusion: This study illustrates the ability of CS/Plu nanopolymer to intensify synergy between antibiotics, thereby providing a promising potential to rejuvenate antibiotics considered ineffective against resistant pathogens.
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Affiliation(s)
- Safy Hadiya
- Assiut International Center of Nanomedicine, Al-Rajhy Liver Hospital, Assiut University, Assiut, 71515, Egypt
| | - Reham A Ibrahem
- Department of Microbiology & Immunology, Faculty of Pharmacy, Minia University, Minia, 61511, Egypt
| | - Rehab M Abd El-Baky
- Department of Microbiology & Immunology, Faculty of Pharmacy, Minia University, Minia, 61511, Egypt
- Department of Microbiology & Immunology, Faculty of Pharmacy, Deraya University, Minia, 61511, Egypt
| | - Mahmoud Elsabahy
- School of Biotechnology, Badr University in Cairo, Badr City, 11829, Egypt
- Department of Chemistry, Texas A&M University, College Station, TX 77842, USA
| | - Abeer Mr Hussein
- Pharmacology Department, Faculty of Medicine, Assiut University, Assiut, 71515, Egypt
| | - Mohammed Em Tolba
- Medical Parasitology Department, Faculty of Medicine, Assiut University, Assiut, 71515, Egypt
| | - Sherine A Aly
- Department of Microbiology & Immunology, Faculty of Medicine, Assiut University, Assiut, 71515, Egypt
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2
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Kamble PA, Phadke M. Use of checkerboard assay to determine the synergy between essential oils extracted from leaves of Aegle marmelos (L.) Correa and nystatin against Candida albicans. Ayu 2023; 44:38-43. [PMID: 38505112 PMCID: PMC10946663 DOI: 10.4103/ayu.ayu_397_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 11/01/2023] [Accepted: 12/25/2023] [Indexed: 03/21/2024] Open
Abstract
Background Candida albicans is one of the most common pathogenic yeasts, responsible for causing candidiasis. The use of conventional antifungal agents for the treatment of Candida is reported to be less effective and hence alternative therapies for the treatment are needed. Essential oils of medicinal plants may serve as a strong candidate for natural products in modern therapies. Aim The aim of this study was to determine the synergistic potential of essential oils extracted from leaves of Aegle marmelos (L.) Correa and a potent antifungal agent, nystatin, against three clinical isolates of C. albicans using checkerboard assay. Materials and methods The antifungal activity of the essential oils of A. marmelos was screened against test cultures by disc diffusion technique. Antibiograms of the test organisms were developed. To determine the minimum fungicidal concentration of the essential oil and nystatin, the broth microdilution method was employed, and a checkerboard assay was used to investigate the synergistic potential of the essential oil and nystatin against the clinical isolates under study. The data were expressed as mean ± standard deviation. Results The Σ fractional inhibitory concentration values were calculated as 0.12, 0.37, and 0.28 for three different strains of C. albicans used, respectively, which was <0.5, therefore, the synergy was demonstrated between essential oils and nystatin against the test cultures. Conclusions Combinatorial therapy of the essential oils extracted from the leaves of A. marmelos and nystatin may be considered a line of treatment for candidal infections.
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Affiliation(s)
- Pramod Ananda Kamble
- Department of Microbiology, SIES College of Arts, Science and Commerce, Mumbai, Maharashtra, India
| | - Manju Phadke
- Department of Microbiology, SIES College of Arts, Science and Commerce, Mumbai, Maharashtra, India
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Deolankar MS, Carr RA, Fliorent R, Roh S, Fraimow H, Carabetta VJ. Evaluating the Efficacy of Eravacycline and Omadacycline against Extensively Drug-Resistant Acinetobacter baumannii Patient Isolates. Antibiotics (Basel) 2022; 11:antibiotics11101298. [PMID: 36289956 PMCID: PMC9598263 DOI: 10.3390/antibiotics11101298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 11/16/2022] Open
Abstract
For decades, the spread of multidrug-resistant (MDR) Acinetobacter baumannii has been rampant in critically ill, hospitalized patients. Traditional antibiotic therapies against this pathogen have been failing, leading to rising concerns over management options for patients. Two new antibiotics, eravacycline and omadacycline, were introduced to the market and have shown promising results in the treatment of Gram-negative infections. Since these drugs are newly available, there is limited in vitro data about their effectiveness against MDR A. baumannii or even susceptible strains. Here, we examined the effectiveness of 22 standard-of-care antibiotics, eravacycline, and omadacycline against susceptible and extensively drug-resistant (XDR) A. baumannii patient isolates from Cooper University Hospital. Furthermore, we examined selected combinations of eravacycline or omadacycline with other antibiotics against an XDR strain. We demonstrated that this collection of strains is largely resistant to monotherapies of carbapenems, fluoroquinolones, folate pathway antagonists, cephalosporins, and most tetracyclines. While clinical breakpoint data are not available for eravacycline or omadacycline, based on minimum inhibitory concentrations, eravacycline was highly effective against these strains. The aminoglycoside amikacin alone and in combination with eravacycline or omadacycline yielded the most promising results. Our comprehensive characterization offers direction in the treatment of this deadly infection in hospitalized patients.
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Affiliation(s)
- Manas S. Deolankar
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Rachel A. Carr
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | | | - Sean Roh
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Henry Fraimow
- Department of Medicine, Division of Infectious Diseases, Cooper University Hospital, Camden, NJ 08103, USA
| | - Valerie J. Carabetta
- Department of Biomedical Sciences, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
- Correspondence: ; Tel.: +1-856-956-2736
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4
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Khodaparast S, Ghanbari F, Zamani H. Evaluation of the effect of ibuprofen in combination with ciprofloxacin on the virulence-associated traits, and efflux pump genes of Pseudomonas aeruginosa. World J Microbiol Biotechnol 2022; 38:125. [PMID: 35657493 DOI: 10.1007/s11274-022-03316-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/20/2022] [Indexed: 12/01/2022]
Abstract
Biofilm formation and antibiotic efflux are two determinant factors in the development of drug resistance phenotype by Pseudomonas aeruginosa. Non-steroid anti-inflammatory drugs have shown the antimicrobial potential to be used in combination with antibiotics against bacterial pathogens. In this work, the effect of ibuprofen alone and in combination with ciprofloxacin on some virulence traits and the expression of the alginate synthesis and efflux pump genes of clinical isolates of P. aeruginosa was investigated. The checkerboard titration assay was used to evaluate the synergism of the drugs. P. aeruginosa strains were grown in the presence of sub-inhibitory concentrations of the drug and their biofilm formation level, swarming, swimming, and hemolytic activity were assessed. Also, the relative expression of the alg44, algT/U, mexB, and oprM genes was determined by qPCR assay. The MIC of ibuprofen and ciprofloxacin were measured 2048 and 32 µg/mL and the drugs showed synergic antibacterial activity (FIC = 0.4). Moreover, ibuprofen alone and in combination with ciprofloxacin, significantly reduced the expression of alg44 (0.22 and 0.25 folds) and algT/U (0.26 and 0.37 folds) genes, while increased the expression of the mexB (1.64 and 1.83 folds) and oprM (1.36 and 1.92 folds) genes. Simultaneous treatment of bacterial cells with ibuprofen and ciprofloxacin significantly decreased bacterial biofilm formation (65%), swimming, swarming, and hemolytic activity (85%), compared with the control. This work suggests that ibuprofen has considerable anti-virulence potential against P. aeruginosa and could be employed for combination therapy with antibiotics after further characterizations.
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Affiliation(s)
- Samira Khodaparast
- Depertment of Biology, Faculty of Science, University of Guilan, Rasht, Iran
| | - Fatemeh Ghanbari
- Department of Biology, University of Guilan, University Campus 2, Rasht, Iran
| | - Hojjatolah Zamani
- Depertment of Biology, Faculty of Science, University of Guilan, Rasht, Iran.
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5
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Orientin Enhances Colistin-Mediated Bacterial Lethality through Oxidative Stress Involvement. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2022; 2022:3809232. [PMID: 35586695 PMCID: PMC9110166 DOI: 10.1155/2022/3809232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/19/2022] [Accepted: 04/22/2022] [Indexed: 11/21/2022]
Abstract
Bacterial resistance to colistin has prompted the search for alternative strategies to enhance antibacterial potential. Combination therapy remains one of the viable strategies in antibacterial therapy and has been proven to be effective in reducing the risk of resistance. In this study, the potential of orientin for enhancing the antibacterial activity of colistin was assessed against Klebsiella pneumoniae and Pseudomonas aeruginosa in vitro. The involvement of oxidative stress in such enhancement was also assessed. The minimum inhibitory concentrations (MICs) of colistin and orientin were 16 μg/mL and 64 μg/mL against K. pneumoniae and 64 μg/mL and 256 μg/mL against P. aeruginosa respectively. For the combination therapy, orientin potentiates the antibacterial effect of colistin with a friction inhibitory concentration index (FICI) of 0.37 and 0.31 against K. pneumoniae and P. aeruginosa, respectively. This observation suggests a synergistic interaction, with the MIC of colistin being reduced by 3- and 4-fold in the presence of orientin against K. pneumoniae and P. aeruginosa, respectively. Additionally, treatment with the combination of colistin and orientin induced oxidative stress against both organisms through increased cellular levels of superoxide anion radicals with concomitant increase in NAD+/NADH and ADP/ATP ratios. These findings suggest that orientin enhanced colistin in the killing of the test bacteria and the cotreatment of colistin and orientin induced oxidative stress, through reactive oxygen species generation, which consequently facilitated bacterial lethality without causing drug-drug interactions. Although, the data presented in this study has supported the capability of orientin for strengthening antibacterial activity of colistin toward the fight against drug-resistant Gram-negative bacteria, studies focusing on the exact target and mechanism of action of orientin are underway.
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6
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Stanković N, Mihajilov-Krstev T, Zlatković B, Stankov-Jovanović V, Kocić B, Čomić L. Antibacterial and antioxidant activity of wild-growing Angelica species (Apiaceae) from Balkan Peninsula against human pathogenic bacteria. JOURNAL OF ESSENTIAL OIL RESEARCH 2020. [DOI: 10.1080/10412905.2020.1787883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- Nemanja Stanković
- Department for sanitary microbiology, Institute for Public Health , Niš, Serbia
| | | | - Bojan Zlatković
- Faculty of Science and Mathematics, University of Niš , Niš, Serbia
| | | | | | - Ljiljana Čomić
- Faculty of Science, University of Kragujevac , Kragujevac, Serbia
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7
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Garza-Cervantes JA, Meza-Bustillos JF, Resendiz-Hernández H, Suárez-Cantú IA, Ortega-Rivera OA, Salinas E, Escárcega-González CE, Morones-Ramírez JR. Re-sensitizing Ampicillin and Kanamycin-Resistant E. coli and S. aureus Using Synergistic Metal Micronutrients-Antibiotic Combinations. Front Bioeng Biotechnol 2020; 8:612. [PMID: 32671033 PMCID: PMC7327704 DOI: 10.3389/fbioe.2020.00612] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 05/19/2020] [Indexed: 01/19/2023] Open
Abstract
Due to the recent emergence of multi-drug resistant strains, the development of novel antimicrobial agents has become a critical issue. The use of micronutrient transition metals is a promising approach to overcome this problem since these compounds exhibit significant toxicity at low concentrations in prokaryotic cells. In this work, we demonstrate that at concentrations lower than their minimal inhibitory concentrations and in combination with different antibiotics, it is possible to mitigate the barriers to employ metallic micronutrients as therapeutic agents. Here, we show that when administered as a combinatorial treatment, Cu2+, Zn2+, Co2+, Cd2+, and Ni2+ increase susceptibility of Escherichia coli and Staphylococcus aureus to ampicillin and kanamycin. Furthermore, ampicillin-resistant E. coli is re-sensitized to ampicillin when the ampicillin is administered in combination with Cu2+, Cd2+, or Ni2. Similarly, Cu2+, Zn2+, or Cd2+ re-sensitize kanamycin-resistant E. coli and S. aureus to kanamycin when administered in a combinatorial treatment with those transition metals. Here, we demonstrate that for both susceptible and resistant bacteria, transition-metal micronutrients, and antibiotics interact synergistically in combinatorial treatments and exhibit increased effects when compared to the treatment with the antibiotic alone. Moreover, in vitro and in vivo assays, using a murine topical infection model, showed no toxicological effects of either treatment at the administered concentrations. Lastly, we show that combinatorial treatments can clear a murine topical infection caused by an antibiotic-resistant strain. Altogether, these results suggest that antibiotic-metallic micronutrient combinatorial treatments will play an important role in future developments of antimicrobial agents and treatments against infections caused by both susceptible and resistant strains.
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Affiliation(s)
- Javier Alberto Garza-Cervantes
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, UANL, San Nicolás de los Garza, Mexico.,Centro de Investigación en Biotecnologíay Nanotecnología, Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Apodaca, Mexico
| | - Jesus F Meza-Bustillos
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, UANL, San Nicolás de los Garza, Mexico
| | - Haziel Resendiz-Hernández
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, UANL, San Nicolás de los Garza, Mexico
| | - Ivan A Suárez-Cantú
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, UANL, San Nicolás de los Garza, Mexico
| | - Oscar Antonio Ortega-Rivera
- Departamento de Microbiología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Eva Salinas
- Departamento de Microbiología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Aguascalientes, Mexico
| | - Carlos Enrique Escárcega-González
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, UANL, San Nicolás de los Garza, Mexico.,Centro de Investigación en Biotecnologíay Nanotecnología, Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Apodaca, Mexico
| | - Jose Ruben Morones-Ramírez
- Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, UANL, San Nicolás de los Garza, Mexico.,Centro de Investigación en Biotecnologíay Nanotecnología, Facultad de Ciencias Químicas, Universidad Autónoma de Nuevo León, Apodaca, Mexico
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8
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Feldman M, Smoum R, Mechoulam R, Steinberg D. Potential combinations of endocannabinoid/endocannabinoid-like compounds and antibiotics against methicillin-resistant Staphylococcus aureus. PLoS One 2020; 15:e0231583. [PMID: 32294120 PMCID: PMC7159245 DOI: 10.1371/journal.pone.0231583] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 03/27/2020] [Indexed: 12/18/2022] Open
Abstract
Infections caused by antibiotic-resistant strains of Staphylococcus aureus have reached epidemic proportions globally. Our previous study showed antimicrobial effects of anandamide (AEA) and arachidonoyl serine (AraS) against methicillin (MET)-resistant S. aureus (MRSA) strains, proposing the therapeutic potential of these endocannabinoid/endocannabinoid-like (EC/EC-like) agents for the treatment of MRSA. Here, we investigated the potential synergism of combinations of AEA and AraS with different types of antibiotics against MRSA grown under planktonic growth or biofilm formation. The most effective combinations under planktonic conditions were mixtures of AEA and ampicillin (AMP), and of AraS and gentamicin (GEN). The combination with the highest synergy in the biofilm formation against all tested bacterial strains was AEA and MET. Moreover, the combination of AraS and MET synergistically caused default of biofilm formation. Slime production of MRSA was also dramatically impaired by AEA or AraS combined with MET. Our data suggest the novel potential activity of combinations of EC/EC-like agents and antibiotics in the prevention of MRSA biofilm formation.
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Affiliation(s)
- Mark Feldman
- Biofilm Research Laboratory, Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
- * E-mail:
| | - Reem Smoum
- The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Raphael Mechoulam
- The Institute for Drug Research, School of Pharmacy, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Doron Steinberg
- Biofilm Research Laboratory, Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
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Antibacterial Activity of combinatorial treatments composed of transition-metal/antibiotics against Mycobacterium tuberculosis. Sci Rep 2019; 9:5471. [PMID: 30940878 PMCID: PMC6445279 DOI: 10.1038/s41598-019-42049-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/18/2019] [Indexed: 12/12/2022] Open
Abstract
Notwithstanding evidence that tuberculosis (TB) is declining, one of the greatest concerns to public health is the emergence and spread of multi-drug resistant strains of Mycobacterium tuberculosis (MDR-TB). MDR-TB are defined as strains which are resistant to at least isoniazid (INH) and rifampicin, the two most potent TB drugs, and their increasing incidence is a serious concern. Recently, notable efforts have been spent on research to pursue novel treatments against MDR-TB, especially on synergistic drug combinations as they have the potential to improve TB treatment. Our research group has previously reported promising synergistic antimicrobial effects between transition-metal compounds and antibiotics in Gram-negative and Gram-positive bacteria. In this work, we evaluated antimycobacterial activity of transition-metals/antibiotics combinatorial treatments against first-line drug resistant strains of Mycobacterium tuberculosis. Our data showed that INH/AgNO3 combinatorial treatment had an additive effect (bactericidal activity) in an isoniazid-resistant clinical strain of Mycobacterium tuberculosis. Moreover, in vitro evaluation of cytotoxicity induced by both, the individual tratments of AgNO3 and INH and the combinatorial treatment of INH/AgNO3 in murine RAW 264.7 macrophages and human A549 lung cells; showed no toxic effects. Together, this data suggests that the INH/AgNO3 combinatorial treatment could be used in the development of new strategies to treat resistant strains of Mycobacterium tuberculosis.
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10
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Laishram S, Pragasam AK, Bakthavatchalam YD, Veeraraghavan B. An update on technical, interpretative and clinical relevance of antimicrobial synergy testing methodologies. Indian J Med Microbiol 2018; 35:445-468. [PMID: 29405135 DOI: 10.4103/ijmm.ijmm_17_189] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Testing for antimicrobial interactions has gained popularity in the last decade due to the increasing prevalence of drug-resistant organisms and limited options for the treatment of these infections. In vitro combination testing provides information, on which two or more antimicrobials can be combined for a good clinical outcome. Amongst the various in vitro methods of drug interactions, time-kill assay (TKA), checkerboard (CB) assay and E-test-based methods are most commonly used. Comparative performance of these methods reveals the TKA as the most promising method to detect synergistic combinations followed by CB assay and E-test. Various combinations of antimicrobials have been tested to demonstrate synergistic activity. Promising results were obtained for the combinations of meropenem plus colistin and rifampicin plus colistin against Acinetobacter baumannii, colistin plus carbapenem and carbapenem plus fluoroquinolones against Pseudomonas aeruginosa and colistin/polymyxin B plus rifampicin/meropenem against Klebsiella pneumoniae. Antagonism was detected in only few instances. The presence of synergy or antagonism with a combination seems to correlate with minimum inhibitory concentration of the agent and molecular mechanism involved in the resistance. Further studies need to be conducted to assess the utility of in vitro testing to predict clinical outcome and direct therapy for drug-resistant organisms.
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Affiliation(s)
- Shakti Laishram
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu,, India
| | - Agila Kumari Pragasam
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu,, India
| | | | - Balaji Veeraraghavan
- Department of Clinical Microbiology, Christian Medical College, Vellore, Tamil Nadu,, India
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11
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Makarasen A, Reukngam N, Khlaychan P, Chuysinuan P, Isobe M, Techasakul S. Mode of action and synergistic effect of valinomycin and cereulide with amphotericin B against Candida albicans and Cryptococcus albidus. J Mycol Med 2017; 28:112-121. [PMID: 29276078 DOI: 10.1016/j.mycmed.2017.11.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2017] [Revised: 11/22/2017] [Accepted: 11/29/2017] [Indexed: 11/16/2022]
Abstract
Both valinomycin and cereulide are cyclic depsipeptides and are known K+ ion-selective ionophores. Valinomycin and cereulide feature low minimum inhibitory concentration (MIC) values against Candida albicans and Cryptococcus albidus. This study aims at investigating the mode of action and verifying the efficacy of valinomycin or cereulide alone and in combination with amphotericin B (AmB) in vitro against both microorganisms. Based on the results from membrane permeability and fluidity assays for detection of plasma membrane permeabilization and membrane dynamics, the present study demonstrated that valinomycin and cereulide exhibit antifungal activity against C. albicans and C. albidus by interrupting membrane-associated function. The mode of action of both valinomycin and cereulide are similar with that of AmB. Time-kill kinetics assay showed that valinomycin and cereulide exhibit fungistatic activity, whereas AmB features fungicidal activity. Additionally, the combination of compounds between each cyclic peptide and AmB reached maximal fungicidal activity more rapidly than AmB alone. This result corresponded with findings of scanning electron microscopy, fractional inhibitory concentration index and minimum fungicidal concentration (MFC)/MIC ratio, indicating that combinations of the drugs show synergistic effects for inhibiting the growth of these fungal strains. Sorbitol and ergosterol assays showed that both cyclic peptides affected cell wall and membrane components due to increases in MIC value, as observed in medium with sorbitol and ergosterol. Valinomycin and cereulide may promote permeability of fungal cell wall and cell membrane when used in combination with AmB.
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Affiliation(s)
- A Makarasen
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - N Reukngam
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - P Khlaychan
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - P Chuysinuan
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - M Isobe
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand
| | - S Techasakul
- Department of Chemistry, Laboratory of Organic Synthesis, Chulabhorn Research Institute, 54, Vipavadee-Rangsit Highway, Bangkok 10210, Thailand.
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12
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AlNeyadi SS, Salem AA, Ghattas MA, Atatreh N, Abdou IM. Antibacterial activity and mechanism of action of the benzazole acrylonitrile-based compounds: In vitro , spectroscopic, and docking studies. Eur J Med Chem 2017; 136:270-282. [DOI: 10.1016/j.ejmech.2017.05.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2016] [Revised: 05/01/2017] [Accepted: 05/02/2017] [Indexed: 01/18/2023]
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13
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Garza-Cervantes JA, Chávez-Reyes A, Castillo EC, García-Rivas G, Antonio Ortega-Rivera O, Salinas E, Ortiz-Martínez M, Gómez-Flores SL, Peña-Martínez JA, Pepi-Molina A, Treviño-González MT, Zarate X, Elena Cantú-Cárdenas M, Enrique Escarcega-Gonzalez C, Morones-Ramírez JR. Synergistic Antimicrobial Effects of Silver/Transition-metal Combinatorial Treatments. Sci Rep 2017; 7:903. [PMID: 28420878 PMCID: PMC5429853 DOI: 10.1038/s41598-017-01017-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 03/23/2017] [Indexed: 12/17/2022] Open
Abstract
Due to the emergence of multi-drug resistant strains, development of novel antibiotics has become a critical issue. One promising approach is the use of transition metals, since they exhibit rapid and significant toxicity, at low concentrations, in prokaryotic cells. Nevertheless, one main drawback of transition metals is their toxicity in eukaryotic cells. Here, we show that the barriers to use them as therapeutic agents could be mitigated by combining them with silver. We demonstrate that synergism of combinatorial treatments (Silver/transition metals, including Zn, Co, Cd, Ni, and Cu) increases up to 8-fold their antimicrobial effect, when compared to their individual effects, against E. coli and B. subtilis. We find that most combinatorial treatments exhibit synergistic antimicrobial effects at low/non-toxic concentrations to human keratinocyte cells, blast and melanoma rat cell lines. Moreover, we show that silver/(Cu, Ni, and Zn) increase prokaryotic cell permeability at sub-inhibitory concentrations, demonstrating this to be a possible mechanism of the synergistic behavior. Together, these results suggest that these combinatorial treatments will play an important role in the future development of antimicrobial agents and treatments against infections. In specific, the cytotoxicity experiments show that the combinations have great potential in the treatment of topical infections.
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Affiliation(s)
- Javier A Garza-Cervantes
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Cd, Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
- Centro de Investigacion en Biotecnologia y Nanotoxicologia, Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Parque de Investigacion e Innovacion Tecnologica, Km. 10 autopista al Aeropuerto Internacional Mariano Escobedo, Apodaca, Nuevo Leon, 66629, Mexico
| | - Arturo Chávez-Reyes
- Centro de Investigación y de Estudios Avanzados del IPN, Unidad Monterrey, Parque PIIT, 66600, Apodaca, Nuevo León, Mexico
| | - Elena C Castillo
- Cátedra de Cardiología y Medicina Vascular, Escuela de Medicina, Tecnologico de Monterrey, Monterrey, Nuevo León, Mexico
- Centro de Investigación Biomédica, Hospital Zambrano-Hellion, Tecnologico de Monterrey, San Pedro Garza-García, Nuevo León, Mexico
| | - Gerardo García-Rivas
- Cátedra de Cardiología y Medicina Vascular, Escuela de Medicina, Tecnologico de Monterrey, Monterrey, Nuevo León, Mexico
- Centro de Investigación Biomédica, Hospital Zambrano-Hellion, Tecnologico de Monterrey, San Pedro Garza-García, Nuevo León, Mexico
| | - Oscar Antonio Ortega-Rivera
- Departamento de Microbiología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Colonia Ciudad Universitaria C.P., 20131, Aguascalientes, Aguascalientes, Mexico
| | - Eva Salinas
- Departamento de Microbiología, Centro de Ciencias Básicas, Universidad Autónoma de Aguascalientes, Av. Universidad 940, Colonia Ciudad Universitaria C.P., 20131, Aguascalientes, Aguascalientes, Mexico
| | - Margarita Ortiz-Martínez
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Cd, Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
| | - Sara Leticia Gómez-Flores
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Cd, Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
| | - Jorge A Peña-Martínez
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Cd, Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
| | - Alan Pepi-Molina
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Biológicas, Av. Universidad s/n, Cd. Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
| | - Mario T Treviño-González
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ingeniería Mecánica y Eléctrica, Av. Universidad s/n, Cd. Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
| | - Xristo Zarate
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Cd, Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
- Centro de Investigacion en Biotecnologia y Nanotoxicologia, Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Parque de Investigacion e Innovacion Tecnologica, Km. 10 autopista al Aeropuerto Internacional Mariano Escobedo, Apodaca, Nuevo Leon, 66629, Mexico
| | - María Elena Cantú-Cárdenas
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Cd, Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
- Centro de Investigacion en Biotecnologia y Nanotoxicologia, Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Parque de Investigacion e Innovacion Tecnologica, Km. 10 autopista al Aeropuerto Internacional Mariano Escobedo, Apodaca, Nuevo Leon, 66629, Mexico
| | - Carlos Enrique Escarcega-Gonzalez
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Cd, Universitaria, 66451, San Nicolás de los Garza, NL, Mexico
- Centro de Investigacion en Biotecnologia y Nanotoxicologia, Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Parque de Investigacion e Innovacion Tecnologica, Km. 10 autopista al Aeropuerto Internacional Mariano Escobedo, Apodaca, Nuevo Leon, 66629, Mexico
| | - J Rubén Morones-Ramírez
- Universidad Autónoma de Nuevo León, UANL, Facultad de Ciencias Químicas, Av. Universidad s/n, Cd, Universitaria, 66451, San Nicolás de los Garza, NL, Mexico.
- Centro de Investigacion en Biotecnologia y Nanotoxicologia, Facultad de Ciencias Quimicas, Universidad Autonoma de Nuevo Leon, Parque de Investigacion e Innovacion Tecnologica, Km. 10 autopista al Aeropuerto Internacional Mariano Escobedo, Apodaca, Nuevo Leon, 66629, Mexico.
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Hirzel C, Hirzberger L, Furrer H, Endimiani A. Bactericidal activity of penicillin, ceftriaxone, gentamicin and daptomycin alone and in combination against Aerococcus urinae. Int J Antimicrob Agents 2016; 48:271-6. [PMID: 27451085 DOI: 10.1016/j.ijantimicag.2016.05.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Revised: 05/11/2016] [Accepted: 05/14/2016] [Indexed: 11/15/2022]
Abstract
Aerococcus urinae can cause severe infections (bacteraemia and endocarditis) that are associated with high mortality. However, data on the bactericidal and synergistic activity for clinically implemented antibiotics are scarce. Time-kill analyses were performed on two clinical isolates (AU1 and AU2) and the reference strain ATCC 700306 for penicillin (PG), ceftriaxone (CRO), gentamicin (GEN), daptomycin (DAP) and their combinations. AU1 and AU2 were CRO-resistant (MICs, 2 µg/mL) and ATCC 700306 was high-level GEN-resistant (MIC, 512 µg/mL), whereas all strains were PG- and DAP-susceptible (MICs, ≤0.125 and ≤1 µg/mL, respectively). CFU counts were determined at various time points from 0 to 48 h. All experiments were performed at 0.5×, 1×, 2× and 4× MIC. PG and CRO were not bactericidal for all strains, whereas DAP exhibited bactericidal activity at all concentrations for AU2 and ATCC 700306. The combination of PG or CRO with GEN was bactericidal for AU1 and AU2 at antibiotic concentrations ≥1× MIC. Bactericidal synergism was detected for PG or CRO combined with GEN in the two clinical isolates. PG plus CRO showed non-bactericidal synergism for ATCC 700306. DAP with GEN was synergistic at 1× MIC for AU1, whereas the killing activity of DAP was too pronounced to detect potential synergism in AU2. The combination of PG or CRO with GEN is synergistic and bactericidal. Moreover, these in vitro data suggest that DAP may represent a potential bactericidal treatment alternative against A. urinae. This finding could be important for the treatment of patients with a β-lactam allergy or renal insufficiency.
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Affiliation(s)
- Cédric Hirzel
- Department of Infectious Diseases, Bern University Hospital (Inselspital), University of Bern, Poliklinik Trakt 2, CH-3010 Bern, Switzerland
| | - Lea Hirzberger
- Department of Infectious Diseases, Bern University Hospital (Inselspital), University of Bern, Poliklinik Trakt 2, CH-3010 Bern, Switzerland; Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, CH-3010 Bern, Switzerland
| | - Hansjakob Furrer
- Department of Infectious Diseases, Bern University Hospital (Inselspital), University of Bern, Poliklinik Trakt 2, CH-3010 Bern, Switzerland
| | - Andrea Endimiani
- Institute for Infectious Diseases, University of Bern, Friedbühlstrasse 51, CH-3010 Bern, Switzerland.
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15
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He M, Shao L, Liu Q, Li J, Lin H, Jing L, Li M, Chen D. Mechanism of synergy between SIPI-8294 and β-lactam antibiotics against methicillin-resistant Staphylococcus aureus. Lett Appl Microbiol 2016; 63:3-10. [PMID: 27173151 DOI: 10.1111/lam.12583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 04/18/2016] [Accepted: 05/10/2016] [Indexed: 12/13/2022]
Abstract
UNLABELLED SIPI-8294, as an erythromycin derivative, has only weak antibacterial effects on MRSA and MSSA. Interestingly, synergistic effect of SIPI-8294 with oxacillin was observed both in vitro and in vivo. Western blot and RT-PCR results demonstrate that mecA expressions were suppressed by SIPI-8294 in MRSA. Furthermore, the knock out of mecA in ATCC 43300 led to the loss of synergy of the combinations while mecA complemented strain showed almost the same synergistic capability compared to the wild type strain. However, the knock out of mecR1 and mecI in MRSA displayed no impact on the synergy of the combinations and the ability of SIPI-8294 to suppress mecA expression. In summary, our study has demonstrated that SIPI-8294 could dramatically reverse MRSA resistance to β-lactams both in vitro and in vivo owing to inhibiting mecA expression. However, mecR1 and mecI, as the pivotal regulatory genes of mecA, do not participate in SIPI-8294-mecA pathway. The research indicates that it may be a promising strategy for combating MRSA infections with the combinations of SIPI-8294 and β-lactam antibiotics. The research of the mechanism is important for structure modification and new drug development. SIGNIFICANCE AND IMPACT OF THE STUDY This study is the first report on the mechanism of synergy between SIPI-8294 and β-lactams against MRSA on the molecular level. In this study, SIPI-8294 showed strong synergistic effects on β-lactam antibiotics both in vitro and in vivo owing to inhibiting mecA expression. As pivotal regulatory genes of mecA, mecR1 and mecI do not participate in SIPI-8294-mecA pathway and are not involved in the synergism of SIPI-8294 and β-lactams. The research indicates that it may be a promising strategy for combating MRSA infections with the combinations of SIPI-8294 and β-lactams. The research is important for structure modification and new drug development.
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Affiliation(s)
- M He
- Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - L Shao
- Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - Q Liu
- Department of Laboratory Medicine, School of Medicine, Renji Hospital, Shanghai Jiaotong University, Shanghai, China
| | - J Li
- Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - H Lin
- Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai, China
| | - L Jing
- Shanghai Biotecan Pharmaceuticals Co., Ltd., Shanghai, China
| | - M Li
- Department of Laboratory Medicine, School of Medicine, Renji Hospital, Shanghai Jiaotong University, Shanghai, China
| | - D Chen
- Shanghai Institute of Pharmaceutical Industry, China State Institute of Pharmaceutical Industry, Shanghai, China
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Zhang S, Wang J, Xu W, Liu Y, Wang W, Wu K, Wang Z, Zhang X. Antibacterial effects of Traditional Chinese Medicine monomers against Streptococcus pneumoniae via inhibiting pneumococcal histidine kinase (VicK). Front Microbiol 2015; 6:479. [PMID: 26042111 PMCID: PMC4438233 DOI: 10.3389/fmicb.2015.00479] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 04/30/2015] [Indexed: 01/28/2023] Open
Abstract
Two-component systems (TCSs) have the potential to be an effective target of the antimicrobials, and thus received much attention in recent years. VicK/VicR is one of TCSs in Streptococcus pneumoniae (S. pneumoniae), which is essential for pneumococcal survival. We have previously obtained several Traditional Chinese Medicine monomers using a computer-based screening. In this study, either alone or in combination with penicillin, their antimicrobial activities were evaluated based on in vivo and in vitro assays. The results showed that the MICs of 5'-(Methylthio)-5'-deoxyadenosine, octanal 2, 4-dinitrophenylhydrazone, deoxyshikonin, kavahin, and dodecyl gallate against S. pneumoniae were 37.1, 38.5, 17, 68.5, and 21 μg/mL, respectively. Time-killing assays showed that these compounds elicited bactericidal effects against S. pneumoniae D39 strain, which led to a 6-log reduction in CFU after exposure to compounds at four times of the MIC for 24 h. The five compounds inhibited the growth of Streptococcus pyogenes, Streptococcus mitis, Streptococcus mutans or Streptococcus pseudopneumoniae, meanwhile, deoxyshikonin and dodecyl gallate displayed strong inhibitory activities against Staphylococcus aureus. These compounds showed no obvious cytotoxicity effects on Vero cells. Survival time of the mice infected by S. pneumoniae strains was prolonged by the treatment with the compounds. Importantly, all of the five compounds exerted antimicrobial effects against multidrug-resistant clinical strains of S. pneumoniae. Moreover, even at sub-MIC concentration, they inhibited cell division and biofilm formation. The five compounds all have enhancement effect on penicillin. Deoxyshikonin and dodecyl gallate showed significantly synergic antimicrobial activity with penicillin in vivo and in vitro, and effectively reduced nasopharyngeal and lung colonization caused by different penicillin-resistant pneumococcal serotypes. In addition, the two compounds also showed synergic antimicrobial activity with erythromycin and tetracycline. Taken together, our results suggest that these novel VicK inhibitors may be promising compounds against the pneumococcus, including penicillin-resistant strains.
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Affiliation(s)
- Shuai Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University Chongqing, China
| | - Jianmin Wang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University Chongqing, China
| | - Wenchun Xu
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University Chongqing, China
| | - Yusi Liu
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University Chongqing, China
| | - Wei Wang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University Chongqing, China
| | - Kaifeng Wu
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University Chongqing, China
| | - Zhe Wang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University Chongqing, China
| | - Xuemei Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University Chongqing, China
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In vitro activity of fosfomycin alone and in combination with ceftriaxone or azithromycin against clinical Neisseria gonorrhoeae isolates. Antimicrob Agents Chemother 2014; 59:1605-11. [PMID: 25547354 DOI: 10.1128/aac.04536-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
New therapeutic strategies are needed to combat the emergence of infections due to multidrug-resistant Neisseria gonorrhoeae. In this study, fosfomycin (FOS) was tested against 89 N. gonorrhoeae isolates using the Etest method, showing MIC50/MIC90s of only 8/16 μg/ml (range, ≤1 to 32 μg/ml). FOS in combination with ceftriaxone (CRO) or azithromycin (AZT) was then evaluated using the checkerboard method for eight strains, including N. gonorrhoeae F89 (CRO-resistant) and AZT-HLR (high-level AZT-resistant). All combinations that included FOS gave indifferent effects (fractional inhibitory concentration [FIC] index values, 1.2 to 2.3 for FOS plus CRO, 1.8 to 3.2 for FOS plus AZT). Time-kill experiments for FOS, CRO, AZT, and their combinations (at 0.5×, 1×, 2×, and 4× the MIC) were performed against N. gonorrhoeae strain ATCC 49226, one N. gonorrhoeae multiantigen sequence typing (NG-MAST) sequence type 1407 (ST1407) strain, F89, and AZT-HLR. For all strains, at 24 h, the results indicated that (i) FOS was bactericidal at 2× the MIC, but after >24 h, there was regrowth of bacteria; (ii) CRO was bactericidal at 0.5× the MIC; (iii) AZT was bactericidal at 4× the MIC; (iv) CRO plus AZT was less bactericidal than was CRO alone; (v) FOS plus AZT was bactericidal at 2× the MIC; and (vi) CRO plus AZT and FOS plus CRO were both bactericidal at 0.5× the MIC, but FOS plus CRO had more rapid effects. FOS is appealing for use in the management of N. gonorrhoeae infections because of its single and oral formulation. However, our results suggest it be used in combination with CRO. After the appropriate clinical trials are conducted, this strategy could be implemented for the treatment of infections due to isolates possessing resistance to CRO and/or AZT.
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Antimicrobial activity of coronarin D and its synergistic potential with antibiotics. BIOMED RESEARCH INTERNATIONAL 2014; 2014:581985. [PMID: 24949458 PMCID: PMC4053275 DOI: 10.1155/2014/581985] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/29/2014] [Indexed: 11/18/2022]
Abstract
Coronarin D is a labdane-type diterpene from the rhizomes of Hedychium coronarium. In the view of our ongoing effort to explore its novel biological activity, antimicrobial activity study of coronarin D was performed. The results showed that coronarin D was active against tested Gram-positive bacteria, inactive for tested Gram-negative bacteria, and weakly active against tested fungi. The antibacterial effect of the combination of coronarin D with nine classical antibiotics against four Gram-positive bacteria was also evaluated. The fractional inhibitory concentration indices (FICI) of coronarin D-antibiotics combinations, calculated from the checkerboard assay, were used as synergism indicator. Out of 36 combinations, 47% showed total synergism, 33% had partial synergistic interaction, 17% showed no effect, and 3% showed antagonism. By combination with coronarin D at concentration of 0.25 minimal inhibitory concentration (MIC), the activities of antibiotics were boosted to 4- to 128-fold. These finding suggested an attractive approach to combat the infectious diseases by using coronarin D-antibiotic drug combination.
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19
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Varposhti M, Abdi Ali A, Mohammadi P. Synergistic Effects of Bismuth Thiols and Various Antibiotics Against Pseudomonas aeruginosa Biofilm. Jundishapur J Microbiol 2014; 7:e9142. [PMID: 25147686 PMCID: PMC4138659 DOI: 10.5812/jjm.9142] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2012] [Revised: 04/24/2013] [Accepted: 05/05/2013] [Indexed: 11/25/2022] Open
Abstract
Background: Pseudomonas aeruginosa is an opportunistic pathogen that takes advantages of some weaknesses in the immune system to initiate an infection. Biofilms of P. aeruginosa can cause chronic opportunistic infections in immunocompromised and elderly patients. This bacterium is considered as a model organism to study antibiotic resistance as well as biofilm formation. In the biofilm structures, bacteria are protected from many harmful environmental factors such as fluctuations in the level of oxygen and nutrients, and the alterations of pH as well as sensitivity to antibiotics. Decreased permeability of biofilms is one of the important reasons of antimicrobial resistance in bacteria. Objectives: In this study the anti-biofilm activity of bismuth thiols in combination with ciprofloxacin, imipenem and ceftazidime against the P. aeruginosa biofilm was investigated. Materials and Methods: Checkerboard method was used to test the susceptibility of biofilms against various antimicrobial combinations. The biofilm formation was measured by 2,3-bis (2-methoxy-4-nitro-5-sulfo-phenyl)-2H-tetrazolium-5-carboxanilide (XTT) colorimetric assay. The fractional bio-film inhibitory concentration was reported for each agent. Results: The combination of bismuth ethanedithiol with ciprofloxacin showed synergistic inhibitory effect on the P. aeruginosa biofilm formation. The combination of bismuth ethanedithiol ciprofloxacin, ceftazidime and imipenem showed synergistic inhibitory effects on the biofilm formation. Furthermore, the combination of bismuth ethanedithiol, imipenem and ceftazidime did not show any synergistic inhibitory effect on biofilm formation. Conclusions: Our studies show that using appropriate concentrations of bismuth thiols in combination with various antibiotics can act synergistically against P. aeruginosa biofilm formation.
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Affiliation(s)
- Maryam Varposhti
- Department of Biology, Faculty of Sciences, Alzahra University, Tehran, IR Iran
| | - Ahya Abdi Ali
- Department of Biology, Faculty of Sciences, Alzahra University, Tehran, IR Iran
- Corresponding author: Ahya Abdi Ali, Department of Biology, Faculty of Sciences, Alzahra University, Tehran, IR Iran. Tel: +98-9122182302, Fax: +98-88058912, E-mail:
| | - Parisa Mohammadi
- Department of Biology, Faculty of Sciences, Alzahra University, Tehran, IR Iran
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20
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Synthesis and anti Methicillin resistant Staphylococcus aureus activity of substituted chalcones alone and in combination with non-beta-lactam antibiotics. Bioorg Med Chem Lett 2012; 22:4555-60. [DOI: 10.1016/j.bmcl.2012.05.112] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2012] [Revised: 05/23/2012] [Accepted: 05/30/2012] [Indexed: 11/24/2022]
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21
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Tran TD, Nguyen TTN, Do TH, Huynh TNP, Tran CD, Thai KM. Synthesis and antibacterial activity of some heterocyclic chalcone analogues alone and in combination with antibiotics. Molecules 2012; 17:6684-96. [PMID: 22728362 PMCID: PMC6268422 DOI: 10.3390/molecules17066684] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 05/25/2012] [Accepted: 05/30/2012] [Indexed: 12/14/2022] Open
Abstract
A series of simple heterocyclic chalcone analogues have been synthesized by Claisen Schmidt condensation reactions between substituted benzaldehydes and heteroaryl methyl ketones and evaluated for their antibacterial activity. The structures of the synthesized chalcones were established by IR and 1H-NMR analysis. The biological data shows that compounds p5, f6 and t5 had strong activities against both susceptible and resistant Staphylococcus aureus strains, but not activity against a vancomycin and methicillin resistant Staphylococcus aureus isolated from a human sample. The structure and activity relationships confirmed that compounds f5, f6 and t5 are potential candidates for future drug discovery and development.
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Affiliation(s)
- Thanh-Dao Tran
- Department of Medicinal Chemistry, School of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City, 41 Dinh Tien Hoang, Dist. 1, Ho Chi Minh City 70000, Vietnam; (T.-T.-N.N.); (T.-N.-P.H.)
- Authors to whom correspondence should be addressed; or (T.-D.T.); or (K.-M.T.); Tel.: +84-903-716-482 (T.-D.T.); +84-909-680-385 (K.-M.T.); Fax: +84-8-3822-5435
| | - Thi-Thao-Nhu Nguyen
- Department of Medicinal Chemistry, School of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City, 41 Dinh Tien Hoang, Dist. 1, Ho Chi Minh City 70000, Vietnam; (T.-T.-N.N.); (T.-N.-P.H.)
| | - Tuong-Ha Do
- Department of Synthetic/Organic Chemistry, Ton Duc Thang University, Nguyen Huu Tho St., Tan Phong Ward, Dist. 7, Ho Chi Minh City 70000, Vietnam;
| | - Thi-Ngoc-Phuong Huynh
- Department of Medicinal Chemistry, School of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City, 41 Dinh Tien Hoang, Dist. 1, Ho Chi Minh City 70000, Vietnam; (T.-T.-N.N.); (T.-N.-P.H.)
| | - Cat-Dong Tran
- Department of Microbiology, School of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City, 41 Dinh Tien Hoang, Dist. 1, Ho Chi Minh City 70000, Vietnam;
| | - Khac-Minh Thai
- Department of Medicinal Chemistry, School of Pharmacy, University of Medicine and Pharmacy at Ho Chi Minh City, 41 Dinh Tien Hoang, Dist. 1, Ho Chi Minh City 70000, Vietnam; (T.-T.-N.N.); (T.-N.-P.H.)
- Authors to whom correspondence should be addressed; or (T.-D.T.); or (K.-M.T.); Tel.: +84-903-716-482 (T.-D.T.); +84-909-680-385 (K.-M.T.); Fax: +84-8-3822-5435
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Boyd N, Nailor MD. Combination antibiotic therapy for empiric and definitive treatment of gram-negative infections: insights from the Society of Infectious Diseases Pharmacists. Pharmacotherapy 2012; 31:1073-84. [PMID: 22026395 DOI: 10.1592/phco.31.11.1073] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The widespread emergence of antibiotic-resistant gram-negative organisms has compromised the utility of current treatment options for severe infections caused by these pathogens. The rate of gram-negative multidrug resistance is worsening, threatening the effectiveness of newer broad-spectrum antibiotic agents. Infections associated with multidrug-resistant Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterobacteriaceae are having a substantial impact on hospital costs and mortality rates. The potential for these resistant gram-negative nosocomial pathogens must always be a primary consideration when selecting antibiotic therapy for critically ill patients. Empiric combination therapy directed at gram-negative pathogens is a logical approach for patients with suspected health care-associated infections, particularly those with risk factors for infections caused by multidrug-resistant pathogens. Although in vitro synergy tests have shown potential benefits of continued combination therapy, convincing clinical data that demonstrate a need for combination therapy once susceptibilities are known are lacking. Thus, deescalation to a single agent once susceptibilities are known is recommended for most patients and pathogens. Use of polymyxins, often in combination with other antimicrobials, may be necessary for salvage therapy.
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Affiliation(s)
- Natalie Boyd
- Parkland Health and Hospital System, Dallas, Texas, USA
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Balaji V, Jeremiah SS, Baliga PR. Polymyxins: Antimicrobial susceptibility concerns and therapeutic options. Indian J Med Microbiol 2011; 29:230-42. [PMID: 21860102 DOI: 10.4103/0255-0857.83905] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The increasing prevalence of multidrug-resistant nosocomial pathogens such as Acinetobacter baumannii, Pseudomonas aeruginosa and Klebsiella pneumoniae poses a great challenge to the treating physicians. The paucity of newer effective antimicrobials has led to renewed interest in the polymyxin group of drugs, as a last resort for treatment of gram-negative bacterial infections. There is a dearth of information on the pharmacological properties of colistin, leading to difficulties in selecting the right dose, dosing interval, and route of administration for treatment, especially in critically-ill patients. The increasing use of colistin over the last few years necessitates the need for accurate and reliable in vitro susceptibility testing methods. Development of heteroresistant strains as a result of colistin monotherapy is also a growing concern. There is a compelling need from the clinicians to provide options for probable and possible colistin combination therapy for multidrug-resistant bacterial infections in the ICU setting. Newer combination drug synergy determination tests are being developed and reported. There are no standardized recommendations from antimicrobial susceptibility testing reference agencies for the testing and interpretation of these drug combinations. Comparison and analysis of these reported methodologies may help to understand and assist the microbiologist to choose the best method that produces accurate results at the earliest. This will help clinicians to select the appropriate combination therapy. In this era of multidrug resistance it is important for the microbiology laboratory to be prepared, by default, to provide timely synergistic susceptibility results in addition to routine susceptibility, if warranted. Not as a favour or at request, but as a responsibility.
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Affiliation(s)
- V Balaji
- Department of Clinical Microbiology, Christian Medical College, Vellore - 632 004, Tamil Nadu, India.
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Al-Hamad A, Burnie J, Upton M. Enhancement of antibiotic susceptibility ofStenotrophomonas maltophiliausing a polyclonal antibody developed against an ABC multidrug efflux pump. Can J Microbiol 2011; 57:820-8. [DOI: 10.1139/w11-076] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Stenotrophomonas maltophilia is an emerging nosocomial pathogen capable of causing healthcare-associated infections, including pneumonia and bacteremia. Intrinsic resistance in S. maltophilia is exhibited towards many broad-spectrum antibiotics, and treatment recommendations are controversial. One of the major causes of antimicrobial resistance is attributed to a robust array of efflux pumps that extrude drug compounds from the cell. Using checkerboard and growth kinetic assays, we evaluated the in vitro activity of a polyclonal antibody raised against an ATP-binding cassette efflux protein in S. maltophilia. Six clinical strains of S. maltophilia and one type strain were challenged with co-trimoxazole, ticarcillin–clavulanate, and ciprofloxacin, alone and in combination with antibody. One clinical strain was tested by growth curve experiments for each antibiotic–antibody combination. The use of antibody resulted in significantly increased susceptibility in 71.4% (15/21) of treatments tested, with 33.3% displaying synergy and 38.1% an additive effect. In growth kinetic studies, synergy was obtained for each antibiotic–antibody combination. Thus, the use of antibody raised against multidrug efflux pumps for the treatment of multidrug-resistant organisms warrants further investigation. Antibody targeting substrate recognition sites, or other functionally important epitopes, may lead to inhibition of multiple efflux pumps that share the same substrate and is an attractive area that should be explored.
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Affiliation(s)
- Arif Al-Hamad
- Medical Microbiology, School of Medicine, University of Manchester, 2nd Floor Clinical Sciences Building, Manchester Royal Infirmary, Manchester M13 9WL, UK
- Divisions of Clinical Microbiology and Infection Prevention and Control, Qatif Central Hospital, P.O. Box 18476, Qatif 31911, Saudi Arabia
| | - James Burnie
- Medical Microbiology, School of Medicine, University of Manchester, 2nd Floor Clinical Sciences Building, Manchester Royal Infirmary, Manchester M13 9WL, UK
| | - Mathew Upton
- Medical Microbiology, School of Medicine, University of Manchester, 2nd Floor Clinical Sciences Building, Manchester Royal Infirmary, Manchester M13 9WL, UK
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Sheng WH, Wang JT, Li SY, Lin YC, Cheng A, Chen YC, Chang SC. Comparative in vitro antimicrobial susceptibilities and synergistic activities of antimicrobial combinations against carbapenem-resistant Acinetobacter species: Acinetobacter baumannii versus Acinetobacter genospecies 3 and 13TU. Diagn Microbiol Infect Dis 2011; 70:380-6. [PMID: 21558048 DOI: 10.1016/j.diagmicrobio.2011.03.003] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 02/24/2011] [Accepted: 03/02/2011] [Indexed: 11/16/2022]
Abstract
Therapeutic options for the treatment of infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) are limited. In vitro activity of amikacin, ciprofloxacin, colistin (polymyxin E), ampicillin-sulbactam, and tigecycline alone and in combination with imipenem against CRAB and carbapenem-resistant Acinetobacter genospecies 3 and 13TU was investigated. Colistin (97% susceptible) and tigecycline (88% and 44% susceptible by US Food and Drug Administration [FDA] and European Committee on Antimicrobial Susceptibility Testing [EUCAST] breakpoints for Enterobacteriaceae, respectively) were the 2 most active agents against CRAB, followed by minocycline (66%), ampicillin/sulbactam (16%), and amikacin (13%). Compared with CRAB isolates, carbapenem-resistant Acinetobacter genospecies 3 and 13TU isolates had higher antimicrobial susceptible rates to ciprofloxacin (88%), amikacin (63%), tigecycline (100% by FDA breakpoint and 88% by EUCAST breakpoint for Enterobacteriaceae, respectively), minocycline (100%), and ampicillin/sulbactam (75%). For the 12 tested CRAB isolates, the checkerboard titration method demonstrated synergy between imipenem and colistin (42%), tigecycline (25%), amikacin (16%), and ampicillin/sulbactam (16%). Time-kill assays revealed antimicrobial synergism for imipenem in combination with colistin (75%), tigecycline (50%), ampicillin/sulbactam (42%), amikacin (42%), and ciprofloxacin (16%). However, antimicrobial synergism between imipenem and combined agents was not present among CRAB isolates with an imipenem MIC ≥ 32 mg/L. The combination of tigecycline and colistin showed good in vitro synergy for CRAB with high imipenem resistance. Our results demonstrate accurate identification of prevalent Acinetobacter species and highlight their different antimicrobial susceptibilities. This knowledge will enable clinicians to select appropriate regimens for treating these infections.
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Affiliation(s)
- Wang-Huei Sheng
- Department of Internal Medicine, National Taiwan University Hospital, Taipei 100, Taiwan
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26
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Russo TA, Page MGP, Beanan JM, Olson R, Hujer AM, Hujer KM, Jacobs M, Bajaksouzian S, Endimiani A, Bonomo RA. In vivo and in vitro activity of the siderophore monosulfactam BAL30072 against Acinetobacter baumannii. J Antimicrob Chemother 2011; 66:867-73. [PMID: 21393224 DOI: 10.1093/jac/dkr013] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES New antibiotics that are active against multidrug-resistant (MDR) Acinetobacter baumannii are urgently needed. BAL30072, a siderophore monosulfactam antibiotic that rapidly penetrates the outer membrane of A. baumannii and has potent activity against most isolates, including those harbouring AmpC β-lactamases and metallo- (class B) or OXA- (class D) carbapenemases, is being developed to meet that need. METHODS We assessed the in vitro activity of BAL30072, meropenem and the combination of BAL30072 and meropenem (2:1 and 1:1 ratios) by MIC and time-kill studies. Proof-of-principle in vivo efficacy was determined using a rat soft-tissue infection model. Five diverse strains with defined phenotypic and genetic profiles were tested (AB307-0294, AB8407, AB1697, AB3340 and AB0057). RESULTS In microdilution assays, combining BAL30072 with meropenem lowered meropenem MICs 2-8-fold. In time-kill studies, the BAL30072 and meropenem combinations resulted in bactericidal concentrations 2-8-fold lower than those of meropenem or BAL30072 alone. In the rat model, BAL30072 was active against four of five strains (AB307-0294, AB8407, AB1697 and AB3340), including meropenem-susceptible and -non-susceptible strains. AB0057 was the only strain resistant to BAL30072 in vivo and in vitro (MIC >64 mg/L). Meropenem was active in vivo against two of the five strains tested (AB307-0294 and AB3340). Both BAL30072 and BAL30072 with meropenem were equally effective in vivo. CONCLUSIONS These data support the continued evaluation of BAL30072 for use in the treatment of infections caused by MDR A. baumannii.
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Affiliation(s)
- Thomas A Russo
- Veterans Administration Western New York Healthcare System, 3495 Bailey Avenue, Buffalo, NY 14215, USA.
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27
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Abstract
AbstractThe aim of the present study is to investigate the antibacterial activity of Salvia officinalis L. aqueous extracts and its synergistic action with preservatives sodium nitrite, sodium benzoate and potassium sorbate in vitro against selected food spoiling bacteria. Synergy was assessed by the checkerboard assay method and quantitatively represented by the FIC index. Synergistic action was established for aqueous extract/ sodium benzoate, aqueous extract/ potassium sorbate, aqueous extract/ sodium nitrite combinations. Synergy was detected in relation to: Agrobacterium tumefaciens, Bacillus subtilis and Proteus sp. Synergy was established at plant extract and preservative concentrations corresponding up to 1/8 MIC values.
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28
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Pankuch GA, Seifert H, Appelbaum PC. Activity of doripenem with and without levofloxacin, amikacin, and colistin against Pseudomonas aeruginosa and Acinetobacter baumannii. Diagn Microbiol Infect Dis 2010; 67:191-7. [PMID: 20338710 DOI: 10.1016/j.diagmicrobio.2010.01.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 01/07/2010] [Accepted: 01/10/2010] [Indexed: 10/19/2022]
Abstract
At 24 h, sub-MIC doripenem and levofloxacin showed synergy against 21 of 25 Pseudomonas aeruginosa strains, sub-MIC doripenem and amikacin against 22 isolates, and sub-MIC doripenem and colistin against 19 isolates. Of 25 Acinetobacter baumannii strains, sub-MIC doripenem and levofloxacin showed synergy against 11 strains at 24 h, sub-MIC doripenem and amikacin against 24 strains, and sub-MIC doripenem and colistin against all isolates.
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Affiliation(s)
- Glenn A Pankuch
- Department of Pathology, Hershey Medical Center, Hershey, PA 17033, USA
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29
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Fujimura S, Takane H, Nakano Y, Watanabe A. In vitro synergy studies based on tazobactam/piperacillin against clinical isolates of metallo-beta-lactamase-producing Pseudomonas aeruginosa. J Antimicrob Chemother 2009; 64:1115-6. [PMID: 19744981 DOI: 10.1093/jac/dkp333] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Olut AI, Erkek E. Early prosthetic valve endocarditis due to Acinetobacter baumannii: A case report and brief review of the literature. ACTA ACUST UNITED AC 2009; 37:919-21. [PMID: 16308232 DOI: 10.1080/00365540500262567] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Acinetobacter is a highly resistant microorganism, commonly isolated in intensive and post-operative care units. Although rarely reported, it may constitute 1 of the several causes of early prosthetic valve endocarditis. A diffuse, red maculopapular rash may be encountered in patients with Acinetobacter endocarditis. Here we present a case of early prosthetic valve endocarditis due to Acinetobacter baumannii and accompanied by a cutaneous eruption.
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Affiliation(s)
- Ali Ilgin Olut
- Unit of Infectious Diseases and Clinical Microbiology, Tepecik SSK Training Hospital, Izmir.
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31
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Minond D, Saldanha SA, Subramaniam P, Spaargaren M, Spicer T, Fotsing JR, Weide T, Fokin VV, Sharpless KB, Galleni M, Bebrone C, Lassaux P, Hodder P. Inhibitors of VIM-2 by screening pharmacologically active and click-chemistry compound libraries. Bioorg Med Chem 2009; 17:5027-37. [PMID: 19553129 DOI: 10.1016/j.bmc.2009.05.070] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2009] [Revised: 05/22/2009] [Accepted: 05/27/2009] [Indexed: 12/27/2022]
Abstract
VIM-2 is an Ambler class B metallo-beta-lactamase (MBL) capable of hydrolyzing a broad-spectrum of beta-lactam antibiotics. Although the discovery and development of MBL inhibitors continue to be an area of active research, an array of potent, small molecule inhibitors is yet to be fully characterized for VIM-2. In the presented research, a compound library screening approach was used to identify and characterize VIM-2 inhibitors from a library of pharmacologically active compounds as well as a focused 'click' chemistry library. The four most potent VIM-2 inhibitors resulting from a VIM-2 screen were characterized by kinetic studies in order to determine K(i) and mechanism of enzyme inhibition. As a result, two previously described pharmacologic agents, mitoxantrone (1,4-dihydroxy-5,8-bis([2-([2-hydroxyethyl]amino)ethyl]amino)-9,10-anthracenedione) and 4-chloromercuribenzoic acid (pCMB) were found to be active, the former as a non-competitive inhibitor (K(i)=K(i)(')=1.5+/-0.2microM) and the latter as a slowly reversible or irreversible inhibitor. Additionally, two novel sulfonyl-triazole analogs from the click library were identified as potent, competitive VIM-2 inhibitors: N-((4-((but-3-ynyloxy)methyl)-1H-1,2,3-triazol-5-yl)methyl)-4-iodobenzenesulfonamide (1, K(i)=0.41+/-0.03microM) and 4-iodo-N-((4-(methoxymethyl)-1H-1,2,3-triazol-5-yl)methyl)benzenesulfonamide (2, K(i)=1.4+/-0.10microM). Mitoxantrone and pCMB were also found to potentiate imipenem efficacy in MIC and synergy assays employing Escherichia coli. Taken together, all four compounds represent useful chemical probes to further investigate mechanisms of VIM-2 inhibition in biochemical and microbiology-based assays.
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Affiliation(s)
- Dmitriy Minond
- Lead Identification, Translational Research Institute, The Scripps Research Institute, Scripps Florida, 130 Scripps Way #1A1, Jupiter, 33458 FL, USA
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32
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Hydroxyl radicals are involved in cell killing by the bacterial topoisomerase I cleavage complex. J Bacteriol 2009; 191:5315-9. [PMID: 19525344 DOI: 10.1128/jb.00559-09] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Escherichia coli expressing SOS-inducing mutant topoisomerase I was utilized to demonstrate that covalent protein-DNA complex accumulation results in oxidative damage. Hydroxyl radicals were detected following mutant topoisomerase induction. The presence of the Fe(2+) chelator 2,2'-dipyridyl and an iscS mutation affecting Fe-S cluster formation protect against topoisomerase I cleavage complex-mediated cell killing.
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33
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Qin L, Li B, Guan J, Zhang G. In vitro synergistic antibacterial activities of helvolic acid on multi-drug resistant Staphylococcus aureus. Nat Prod Res 2009; 23:309-18. [PMID: 19296371 DOI: 10.1080/14786410801972813] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
An agar plate method was established to screen synergistic antibacterial agents other than beta-lactamase inhibitors. By using this method, a strain Aspergillus sp136 was selected for further studies. From the metabolites of this strain, a synergistic antibacterial compound was isolated by bioautographic TLC assay-guided fractionation and identified as helvolic acid. The synergistic effect of helvolic acid to penicillin was about 3 times that of clavulanic acid to penicillin in agar diffusion assay on Bacillus cereus. In checkerboard studies, helvolic acid exhibited synergistic effects with erythromycin on all tested multi-drug resistant Staphylococcus aureus and with penicillin and tetracycline on some multi-drug resistant S. aureus. A pattern of enhanced killing was also found in time-kill studies on multi-drug resistant S. aureus.
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Affiliation(s)
- Ling Qin
- Chengdu Institute of Biology, Chinese Academy of Sciences, People's Republic of China
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34
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Activity of levofloxacin alone and in combination with a DnaK inhibitor against gram-negative rods, including levofloxacin-resistant strains. Antimicrob Agents Chemother 2008; 53:814-7. [PMID: 19015359 DOI: 10.1128/aac.01132-08] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Synergy time-kill testing of levofloxacin alone and in combination with CHP-105, a representative DnaK inhibitor, against 50 gram-negative rods demonstrated that 34 of the 50 strains tested showed significant synergy between levofloxacin and CHP-105 after 12 h and 24 h. Fourteen of these 34 organisms were quinolone resistant (levofloxacin MICs of > or =4 microg/ml).
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35
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36
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Activity of meropenem with and without ciprofloxacin and colistin against Pseudomonas aeruginosa and Acinetobacter baumannii. Antimicrob Agents Chemother 2007; 52:333-6. [PMID: 17967915 DOI: 10.1128/aac.00689-07] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Time-kill synergy studies showed that at 24 h, subinhibitory meropenem and ciprofloxacin concentrations of 0.06 to 128 and 0.03 to 32 microg/ml, respectively, showed synergy against 34/51 Pseudomonas aeruginosa strains; subinhibitory concentrations of meropenem (0.06 to 8 microg/ml) and colistin (0.12 to 1 microg/ml) showed synergy against 13 isolates. Subinhibitory meropenem and ciprofloxacin concentrations of 0.25 to 2 and 0.12 to 16 microg/ml, respectively, showed synergy against 18/52 Acinetobacter baumannii strains at 24 h. Subinhibitory meropenem and colistin concentrations of 0.03 to 64 and 0.06 to 8 microg/ml, respectively, showed synergy against 49 strains at 24 h.
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37
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Joly-Guillou ML, Bergogne-Bérézin E. Les bactéries du genre Acinetobacter revisitées : leur importance actuelle. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/s1294-5501(06)70804-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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38
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Kim DM, Lym Y, Jang SJ, Han H, Kim YG, Chung CH, Hong SP. In vitro efficacy of the combination of ciprofloxacin and cefotaxime against Vibrio vulnificus. Antimicrob Agents Chemother 2005; 49:3489-91. [PMID: 16048966 PMCID: PMC1196224 DOI: 10.1128/aac.49.8.3489-3491.2005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We performed time-kill studies of antimicrobial combinations that included minocycline, cefotaxime, and ciprofloxacin with Vibrio vulnificus ATCC 27562. Cefotaxime-plus-ciprofloxacin combinations acted synergistically against V. vulnificus in vitro, and this combination regimen can be a good choice as the empirical treatment for suspected necrotizing fasciitis due to V. vulnificus.
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Affiliation(s)
- Dong-Min Kim
- Department of Laboratory Medicine, Chosun University Medical School, 588 Seoseok-dong, Dong-gu, Gwang-Ju 501-717, South Korea
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39
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Drago L, De Vecchi E, Nicola L, Legnani D, Lombardi A, Gismondo MR. In vitro synergy and selection of resistance by fluoroquinolones plus amikacin or beta-lactams against extended-spectrum beta-lactamase-producing Escherichia coli. J Chemother 2005; 17:46-53. [PMID: 15828443 DOI: 10.1179/joc.2005.17.1.46] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
This study compared the potential synergy of levofloxacin and ciprofloxacin in combination with cefepime, ceftazidime, imipenem, piperacillin/tazobactam or amikacin, against extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli by using checkerboard and time kill studies. Moreover, selection of resistance was determined by frequency of mutations and by calculating the increase in minimum inhibitory concentrations (MICs) after five serial subcultures on antibiotic-containing plates. Synergy occurred more often with levofloxacin combined with imipenem (7/10 strains) and with levofloxacin or ciprofloxacin with amikacin (10/10) than for the other combinations. Time kill studies showed synergy for levofloxacin combined with amikacin, ceftazidime, imipenem or piperacillin/tazobactam, and for ciprofloxacin combined with amikacin, cefepime or imipenem. Antibiotic combinations selected for resistance less frequently than antibiotics alone. Mutation frequency was <10(-12) for all combinations. In conclusion, the combination of a fluoroquinolone with a beta-lactam or amikacin may provide improved antimicrobial activity and help limit the occurrence of resistance in ESBL-producing E. coli strains.
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Affiliation(s)
- L Drago
- Lab Clinical Microbiology, Dept Clinical Science L Sacco, Via GB Grassi 74, 20157 Milano, Italy.
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40
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Orhan G, Bayram A, Zer Y, Balci I. Synergy tests by E test and checkerboard methods of antimicrobial combinations against Brucella melitensis. J Clin Microbiol 2005; 43:140-3. [PMID: 15634962 PMCID: PMC540140 DOI: 10.1128/jcm.43.1.140-143.2005] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Two different synergy testing methods, the checkerboard and the E test methods, were used to compare the in vitro efficacies of various antimicrobial combinations against 16 Brucella melitensis strains isolated from blood cultures. The rate of agreement of the E test and checkerboard methods was found to be 55%. The most concordant results were found for the streptomycin-doxycycline combination in 12 (75%) tests, in which four strains showed synergistic activity by E test and antagonistic activity by the checkerboard method and in which one strain showed antagonistic activity by both methods. Even though each of these methods uses different conditions and endpoints, the results of both methods frequently agreed.
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Affiliation(s)
- Gani Orhan
- Gaziantep University Medical Faculty, Department of Microbiology and Clinical Microbiology, Universite Bulvari, 27310 Gaziantep, Turkey
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41
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Sato Y, Shibata H, Arakaki N, Higuti T. 6,7-dihydroxyflavone dramatically intensifies the susceptibility of methicillin-resistant or -sensitive Staphylococcus aureus to beta-lactams. Antimicrob Agents Chemother 2004; 48:1357-60. [PMID: 15047543 PMCID: PMC375321 DOI: 10.1128/aac.48.4.1357-1360.2004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have demonstrated that 6,7-dihydroxyflavone by itself has only a weak antibacterial effect on methicillin-resistant Staphylococcus aureus (MRSA) but that at concentrations less than MIC it synergistically elevates the susceptibility of clinically isolated MRSA and methicillin-sensitive S. aureus strains to beta-lactam antibiotics from 8- to 32,800-fold.
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Affiliation(s)
- Youichi Sato
- Faculty of Pharmaceutical Sciences, The University of Tokushima, Tokushima 770-8505, Japan
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42
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Alou L, Cafini F, Sevillano D, Unzueta I, Prieto J. In vitro activity of mupirocin and amoxicillin-clavulanate alone and in combination against staphylococci including those resistant to methicillin. Int J Antimicrob Agents 2004; 23:513-6. [PMID: 15120734 DOI: 10.1016/j.ijantimicag.2003.09.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2003] [Accepted: 09/26/2003] [Indexed: 10/26/2022]
Abstract
Mupirocin and amoxicillin-clavulanate were synergistic against 9 of 49 (18%) strains of methicillin-resistant and methicillin-susceptible Staphylococcus aureus and coagulase-negative staphylococci (CNS). A pattern of enhanced killing was also found using time-kill studies. Time-kill assays were more discriminatory than chequerboard titration assays in demonstrating synergy. These results suggest that combinations of amoxicillin-clavulanate and mupirocin may have therapeutic benefits in prophylaxis against staphylococcal infections.
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Affiliation(s)
- Luis Alou
- Departmento de Microbiología I, Facultad de Medicina, Avda Complutense s/n, 28040 Madrid, Spain
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43
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Ribera A, Doménech-Sanchez A, Ruiz J, Benedi VJ, Jimenez de Anta MT, Vila J. Mutations in gyrA and parC QRDRs are not relevant for quinolone resistance in epidemiological unrelated Stenotrophomonas maltophilia clinical isolates. Microb Drug Resist 2003; 8:245-51. [PMID: 12523620 DOI: 10.1089/10766290260469499] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Clinical strains of Stenotrophomonas maltophilia are often highly resistant to multiple antibiotics and this resistance is steadily rising. Quinolones are included in the group of antimicrobial agents to which this microorganism is developing resistance. Therefore, the aim of this study was to analyze the epidemiological relationship among 22 clinical isolates of S. maltophilia as well as the molecular mechanisms responsible for the acquisition of quinolone-resistance in these strains. The results of the pulsed-field gel electrophoresis (PFGE) showed an heterogenicity of 82% among the strains used in the study. On the other hand, no amino acid changes were found in the quinolone resistance-determining region (QRDR) of either gyrA and parC genes among quinolone-susceptible and -resistant S. maltophilia strains. Besides, the amino acid of the GyrA found in the position equivalent to Ser-83 of E. coli was Gln instead of a Ser or Thr, the amino acids usually encountered in this position among Gram-negative bacteria. The results suggest that there is not a relationship between the presence of this Gln and the resistance to quinolones in S. maltophilia. We can conclude that, contrary to what has been described in other microorganisms, in these S. maltophilia isolates, the development of resistance to quinolones was not related to mutations in the QRDR of gyrA and parC genes. Thus, to our knowledge, this is the first report describing this phenomenon.
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Affiliation(s)
- Anna Ribera
- Institut Clinic d'Infeccions i Immunologia, Hospital ClInic, IDIBAPS, Facultat de Medicina, Universitat de Barcelona, Villarroel, 170, 08036 Barcelona. Spain
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44
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Hsueh PR, Teng LJ, Chen CY, Chen WH, Yu CJ, Ho SW, Luh KT. Pandrug-resistant Acinetobacter baumannii causing nosocomial infections in a university hospital, Taiwan. Emerg Infect Dis 2002. [PMID: 12141969 PMCID: PMC2732518 DOI: 10.3201/eid0808.020014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The rapid emergence (from 0% before 1998 to 6.5% in 2000) of pandrug-resistant Acinetobacter baumannii (PDRAB) was noted in a university hospital in Taiwan. To understand the epidemiology of these isolates, we studied 203 PDRAB isolates, taken from January 1999 to April 2000: 199 from 73 hospitalized patients treated at different clinical settings in the hospital and 4 from environmental sites in an intensive-care unit. Pulsed-field gel electrophoresis analysis and random amplified polymorphic DNA (RAPD) generated by arbitrarily primed polymerase chain reaction of these 203 isolates showed 10 closely related genotypes (10 clones). One (clone 5), belonging to pulsotype E and RAPD pattern 5, predominated (64 isolates, mostly from patients in intensive care). Increasing use of carbapenems and ciprofloxacin (selective pressure) as well as clonal dissemination might have contributed to the wide spread of PDRAB in this hospital.
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Affiliation(s)
- Po-Ren Hsueh
- National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
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Hsueh PR, Teng LJ, Chen CY, Chen WH, Yu CJ, Ho SW, Luh KT. Pandrug-resistant Acinetobacter baumannii causing nosocomial infections in a university hospital, Taiwan. Emerg Infect Dis 2002; 8:827-32. [PMID: 12141969 PMCID: PMC2732518 DOI: 10.3201/eid0805.020014] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The rapid emergence (from 0% before 1998 to 6.5% in 2000) of pandrug-resistant Acinetobacter baumannii (PDRAB) was noted in a university hospital in Taiwan. To understand the epidemiology of these isolates, we studied 203 PDRAB isolates, taken from January 1999 to April 2000: 199 from 73 hospitalized patients treated at different clinical settings in the hospital and 4 from environmental sites in an intensive-care unit. Pulsed-field gel electrophoresis analysis and random amplified polymorphic DNA (RAPD) generated by arbitrarily primed polymerase chain reaction of these 203 isolates showed 10 closely related genotypes (10 clones). One (clone 5), belonging to pulsotype E and RAPD pattern 5, predominated (64 isolates, mostly from patients in intensive care). Increasing use of carbapenems and ciprofloxacin (selective pressure) as well as clonal dissemination might have contributed to the wide spread of PDRAB in this hospital.
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Affiliation(s)
- Po-Ren Hsueh
- National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
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Fung-Tomc JC, Gradelski E, Valera L, Huczko E, Bonner DP. Synergistic activity of the novel des-fluoro(6) quinolone, garenoxacin (BMS-284756), in combination with other antimicrobial agents against Pseudomonas aeruginosa and related species. Int J Antimicrob Agents 2002; 20:57-60. [PMID: 12127712 DOI: 10.1016/s0924-8579(02)00109-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Non-fermentative Gram-negative bacteria (Pseudomonas aeruginosa, Burkholderia cepacia, Stenotrophomonas maltophilia and Acinetobacter spp.) are intrinsically less susceptible to many antimicrobial agents. Two-drug combinations have been used to treat infections caused by less susceptible pathogens. In this study, the antibacterial activity of garenoxacin (GARX) with non-quinolones was examined. The non-quinolones evaluated were cefepime (CEPI), imipenem (IMIP), aztreonam (AZTR), piperacillin-tazobactam (PIPC/TZ), amikacin (AMK), ceftazidime (CTAZ), trimethoprim-sulphamethoxazole (TMP/SMX) and ticarcillin-clavulanate (TICC/CA). Synergism was determined by time-kill analysis using GARX (at 2 x its MIC, not to exceed 4 mg/l) and the second drug (at 1 x MIC, not to exceed its susceptible MIC breakpoint), and is defined as > or = 2 log(10) enhanced killing at 24 h with the combination. Partial synergy is defined as > or = 1.5 log(10) but < 2 log(10) enhanced killing with the drug combination. Synergy/partial synergy was observed most often with GARX plus: CEPI, AZTR, PIPC/TZ, IMIP (five strains each) or AMK (four strains) vs. eight P. aeruginosa; CTAZ, AZTR (five strains each) vs. six B. cepacia; TICC/CA (six strains), CEPI, CTAZ or AMK (five strains each) vs. eight S. maltophilia; and CEPI, AMK (three strains each) or CTAZ, TICC/CA (two strains each) vs. four Acinetobacter spp. In conclusion, synergistic killing was observed frequently with GARX plus a non-quinolone bactericidal agents against non-fermentative Gram-negative bacteria, including strains intermediately susceptible/resistant to one or both agents.
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Affiliation(s)
- J C Fung-Tomc
- Department of Microbiology, Bristol-Myers Squibb Company, 5 Research Parkway, Wallingford, CT 06457, USA.
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Ermertcan S, Hoşgör M, Tünger O, Coşar G. Investigation of synergism of meropenem and ciprofloxacin against Pseudomonas aeruginosa and Acinetobacter strains isolated from intensive care unit infections. SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES 2002; 33:818-21. [PMID: 11760161 DOI: 10.1080/00365540110027222] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The aim of this study was to determine synergistic effects of meropenem and ciprofloxacin against Pseudomonas aeruginosa and Acinetobacter strains isolated from intensive care unit (ICU) infections. A total of 18 P. aeruginosa and 17 Acinetobacter strains were tested. MICs were determined using the broth microdilution method. The synergy of meropenem and ciprofloxacin was investigated in glass tubes using time-kill methodology. The synergistic effect of meropenem and ciprofloxacin in combination was found to be 22% at 0.5 x the MIC and 61% at 1 x the MIC in P. aeruginosa strains. Two strains (11%) showed synergy at both 0.5 and 1 x the MIC. Of the 18 P. aeruginosa strains, 1 strain (6%) did not show a synergistic effect at either 0.5 or 1 x the MIC. In Acinetobacter strains, the synergistic effect of meropenem and ciprofloxacin in combination was found to be 29% at 0.5 x the MIC and 18% at 1 x the MIC. One strain (6%) showed synergy at both 0.5 and 1 x the MIC. Of the 17 Acinetobacter strains, 8 strains (47%) did not show a synergistic effect at either 0.5 or 1 x the MIC. According to the results of this study, the combination of meropenem and ciprofloxacin is more effective than either antibiotic alone in ICU infections due to P. aeruginosa strains.
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Affiliation(s)
- S Ermertcan
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Ege University, Izmir, Turkey.
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48
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Gradelski E, Valera L, Bonner D, Fung-Tomc J. Synergistic activities of gatifloxacin in combination with other antimicrobial agents against Pseudomonas aeruginosa and related species. Antimicrob Agents Chemother 2001; 45:3220-2. [PMID: 11600384 PMCID: PMC90810 DOI: 10.1128/aac.45.11.3220-3222.2001] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2001] [Accepted: 08/03/2001] [Indexed: 11/20/2022] Open
Abstract
Drug combinations have been used to treat serious infections caused by Pseudomonas, Burkholderia, Stenotrophomonas, and Acinetobacter. In this study, the combined drug effects of gatifloxacin (GAT) and nonquinolones were determined by time-kill analysis at clinically achievable drug concentrations. Synergy (>or=2 log(10)-enhanced killing at 24 h) was observed with GAT plus amikacin or a beta-lactam against 50 to 75% of strains, including strains nonsusceptible to one or both drugs.
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Affiliation(s)
- E Gradelski
- Department of Microbiology, Bristol-Myers Squibb Company, Wallingford, Connecticut 06492, USA
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Credito KL, Jacobs MR, Appelbaum PC. Anti-anaerobic activity of levofloxacin alone and combined with clindamycin and metronidazole. Diagn Microbiol Infect Dis 2000; 38:181-3. [PMID: 11109019 DOI: 10.1016/s0732-8893(00)00190-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Microdilution MICs of levofloxacin against twelve anaerobes ranged between 0.5-8.0 microg/ml and those of clindamycin and metronidazole between 0.008-2.0 and 0.25->16.0 microg/ml, respectively. Combination of levofloxacin with clindamycin and/or metronidazole in time-kill tests led to synergy at levofloxacin concentrations at or below the MIC in 7/12 strains.
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Affiliation(s)
- K L Credito
- Department of Pathology, Hershey Medical Center, Hershey, PA 17033, USA
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50
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Bonapace CR, White RL, Friedrich LV, Bosso JA. Evaluation of antibiotic synergy against Acinetobacter baumannii: a comparison with Etest, time-kill, and checkerboard methods. Diagn Microbiol Infect Dis 2000; 38:43-50. [PMID: 11025183 DOI: 10.1016/s0732-8893(00)00163-2] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Acinetobacter baumannii is becoming increasingly resistant to antibiotics, often requiring combination therapy. Numerous methods exist to detect the presence of in vitro synergy with the time-kill and checkerboard tests being widely used. The Epsilometer test (E test) is a new method that is less labor intensive, but has not been evaluated using a wide range of antimicrobials and organisms. We assessed synergy using the time-kill and checkerboard tests and compared the results to the E test method using 10 clinical isolates of A. baumannii. Antimicrobial combinations evaluated consisted of trovafloxacin or tobramycin in combination with cefepime or piperacillin. Synergy was detected with all combinations by either the checkerboard or time-kill method. Synergy was not detected by the Etest method. The agreement between the time-kill test and Etest method was 72% (range 42-97%); for the time-kill and checkerboard tests, agreement was 51% (range 30-67%). The Etest method appears promising although further testing should be performed with additional antimicrobial agents and organisms.
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Affiliation(s)
- C R Bonapace
- Anti-Infective Research Laboratory, College of Pharmacy, Medical University of South Carolina, Charleston, South Carolina, USA
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