scholarly journals Enhancement of Antibiotic Activity by 1,8-Naphthyridine Derivatives against Multi-Resistant Bacterial Strains

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7400
Author(s):  
José B. de Araújo-Neto ◽  
Maria M. C. da Silva ◽  
Cícera D. de M. Oliveira-Tintino ◽  
Iêda M. Begnini ◽  
Ricardo A. Rebelo ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Bacterial Resistance ◽  
Antimicrobial Properties ◽  
Multidrug Resistant ◽  
Antibiotic Activity ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Fluoroquinolone Antibiotics ◽  
Broth Microdilution Method ◽  
Resistant Strains

The search for new antibacterial agents has become urgent due to the exponential growth of bacterial resistance to antibiotics. Nitrogen-containing heterocycles such as 1,8-naphthyridine derivatives have been shown to have excellent antimicrobial properties. Therefore, the purpose of this study was to evaluate the antibacterial and antibiotic-modulating activities of 1,8-naphthyridine derivatives against multi-resistant bacterial strains. The broth microdilution method was used to determine the minimum inhibitory concentration (MIC) of the following compounds: 7-acetamido-1,8-naphthyridin-4(1H)-one and 3-trifluoromethyl-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide. The antibiotic-modulating activity was analyzed using subinhibitory concentrations (MIC/8) of these compounds in combination with norfloxacin, ofloxacin, and lomefloxacin. Multi-resistant strains of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus were used in both tests. Although the compounds had no direct antibacterial activity (MIC ≥ 1.024 µg/mL), they could decrease the MIC of these fluoroquinolones, indicating synergism was obtained from the association of the compounds. These results suggest the existence of a structure–activity relationship in this group of compounds with regard to the modulation of antibiotic activity. Therefore, we conclude that 1,8-naphthyridine derivatives potentiate the activity of fluoroquinolone antibiotics against multi-resistant bacterial strains, and thereby interesting candidates for the development of drugs against bacterial infections caused by multidrug resistant strains.

scholarly journals Curcumin, a Natural Antimicrobial Agent with Strain-Specific Activity

2020 ◽  
Vol 13 (7) ◽  
pp. 153
Author(s):  
Artur Adamczak ◽  
Marcin Ożarowski ◽  
Tomasz M. Karpiński
Keyword(s):  
Inhibitory Concentration ◽  
Specific Activity ◽  
Curcuma Longa ◽  
Antimicrobial Properties ◽  
Antiviral Agent ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Bioactive Substance

Curcumin, a principal bioactive substance of turmeric (Curcuma longa L.), is reported as a strong antioxidant, anti-inflammatory, antibacterial, antifungal, and antiviral agent. However, its antimicrobial properties require further detailed investigations into clinical and multidrug-resistant (MDR) isolates. In this work, we tested curcumin’s efficacy against over 100 strains of pathogens belonging to 19 species. This activity was determined by the broth microdilution method and by calculating the minimum inhibitory concentration (MIC). Our findings confirmed a much greater sensitivity of Gram-positive than Gram-negative bacteria. This study exhibited a significantly larger variation in the curcumin activity than previous works and suggested that numerous clinical strains of widespread pathogens have a poor sensitivity to curcumin. Similarly, the MICs of the MDR types of Staphylococcus aureus, S. haemolyticus, Escherichia coli, and Proteus mirabilis were high (≥2000 µg/mL). However, curcumin was effective against some species and strains: Streptococcus pyogenes (median MIC = 31.25 µg/mL), methicillin-sensitive S. aureus (250 µg/mL), Acinetobacter lwoffii (250 µg/mL), and individual strains of Enterococcus faecalis and Pseudomonas aeruginosa (62.5 µg/mL). The sensitivity of species was not associated with its affiliation to the genus, and it could differ a lot (e.g., S. pyogenes, S. agalactiae and A. lwoffii, A. baumannii). Hence, curcumin can be considered as a promising antibacterial agent, but with a very selective activity.

scholarly journals 656. Sulbactam-Durlobactam MIC Determination: Comparative Evaluation of the New ETEST® SUD to the CLSI 2021 Broth Microdilution Method

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S430-S430
Author(s):  
Veronique Sauvonnet ◽  
Elodie Escoffier ◽  
Christine Franceschi ◽  
Diane Halimi ◽  
Roland Martelin ◽  
...  
Keyword(s):  
Reference Method ◽  
Multidrug Resistant ◽  
Error Rates ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Mueller Hinton ◽  
Broth Microdilution Method ◽  
Lactam Antibiotic ◽  
Visible Growth ◽  
Resistant Strains

Abstract Background Species belonging to the Acinetobacter baumannii-calcoaceticus (ABC) complex, such as A. baumannii, A. pittii and A. nosocomialis, are a major cause of hospital acquired infections and outbreaks with increasing occurrence of multidrug-resistance. Sulbactam-durlobactam (SUD), a combination of one active β-lactam antibiotic (sulbactam) with a new β-lactamase inhibitor (durlobactam), is currently being tested in a phase 3 clinical trial by Entasis Therapeutics for the treatment of serious infections caused by ABC, including multidrug-resistant strains. At the same time, an ETEST® SUD (sulbactam-durlobactam - MIC range 0.004/4-64/4 µg/mL) has been developed and calibrated versus the broth microdilution reference method (BMD) as described by the Clinical and Laboratory Standards Institute (CLSI). This test is intended to determine the MIC of sulbactam-durlobactam for species of the ABC complex. The aim of this study was to perform a first comparative study of ETEST SUD with the CLSI BMD method on a panel of 263 isolates. Methods The panel consisted of 204 A. baumannii, 29 A. pittii, 30 A. nosocomialis, including 24 SUD-resistant strains, and one CLSI QC strain. BMD was performed using the 2021 CLSI guidelines. ETEST SUD was evaluated using the standard ETEST procedure for Acinetobacter spp. (inoculum 0.5 McFarland, Mueller Hinton medium, incubation at 35°C for 20-24h). For each method, the MIC was read at complete inhibition of visible growth. To determine category agreement (CA) and error rates, the sulbactam-durlobactam provisional breakpoint of 4 µg/mL was applied. Results The QC strain MICs were in the expected range with reproducible results. The essential MIC agreement [EA, ±1 dilution] was 97.7% without any tendency to over- or underestimate the MIC when compared to BMD. The CA was 98.5%. Two Very Major Errors, both within the EA, and two Major Errors, one within the EA, were observed. Conclusion In this study, the ETEST SUD was found to be equivalent to the CLSI reference method. MIC end points were easy to read. With a 15-dilution range and simplicity of use, ETEST SUD could represent a valuable tool for MIC determination and could be an alternative to BMD. For Research Use Only. The performance characteristics of this product have not been established yet. Disclosures All Authors: No reported disclosures

In vitro effectiveness of antimicrobial properties of propolis and chlorhexidine on oral pathogens: A comparative study

2020 ◽  
Vol 1 (3) ◽  
pp. 116-125
Author(s):  
Hadis Tavafi ◽  
Maryam- sadat Sadrzadeh-Afshar ◽  
Soroush Niroomand
Keyword(s):  
Periodontal Disease ◽  
Antimicrobial Properties ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Microbial Strains ◽  
Bacteria And Fungi ◽  
Antibacterial And Antifungal ◽  
Oral Conditions

Periodontal disease is one of the most prevalent infectious oral conditions in the present century, and it is necessary to conduct research to find a solution to overcome these diseases. A variety of microbial strains of bacteria and fungi are involved in the pathogenesis of periodontal disease. The use of chemical agents such as mouthwashes is one of the strategies to control these diseases. The purpose of the present study was to compare the antimicrobial effects of propolis and chlorhexidine gluconate (CHX) on the bacterial strains of Streptococcus mutans, Streptococcus pyogenes, Staphylococcus aureus, Enterococcus faecalis, Pseudomonas aeruginosa, and the yeast strain of Candida albicans using the broth microdilution method. The results showed the inhibitory and microbicidal activities of the two substances against the tested microbial strains. The antibacterial and antifungal effects of CHX were more effective reported in this study than that of propolis against the studied pathogens. The results of this study also indicated that the propolis was less effective in inhibiting bacterial growth than the CHX. In addition, the combination of these two solutions had a synergistic effect on inhibition of other studied strains, with the exception of C. albicans and S. aureus. There is a need for further research on strains isolated from oral biofilm to achieve complementary results.

scholarly journals Colistin Resistance of Pseudomonas aeruginosa Isolated from Snakes in Taiwan

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Po-Yu Liu ◽  
Ling-Ling Weng ◽  
Shu-Ying Tseng ◽  
Chou-Chen Huang ◽  
Ching-Chang Cheng ◽  
...  
Keyword(s):  
Oral Cavity ◽  
Multidrug Resistant ◽  
Colistin Resistance ◽  
Chain Reaction ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Resistant Strains ◽  
Polymerase Chain ◽  
First Time

This study included fifty-eight isolates of P. aeruginosa from the oral cavity of snakes that were recruited from clinical cases, captive and wild snakes. The minimum inhibitory concentrations (MICs) for the determination of susceptibility were identified by the broth microdilution method. Polymerase chain reaction (PCR) was employed to detect β-lactamases genes. With regard to antipseudomonal antibiotics, the lowest nonsusceptible rates were in aztreonam (15%), piperacillin/tazobactam (12%), and amikacin (9%). The nonsusceptible rates were high in gentamicin (33%) and colistin (55%). Meanwhile, blaTEM presented in 100% of isolates where blaAmpC, blaOXA-1, and blaOXA-10 came at 94.8%, 89.7%, and 27.6%, respectively. Emergence of multidrug resistant (MDR) strains and colistin-resistant strains highlights the potential breach of public health as P. aeruginosa could be transmitted through either direct contact or indirect dissemination through the environment. This study reports that the highly resistant P. aeruginosa from snakes’ oral cavity were discovered for the very first time in Taiwan.

scholarly journals Antibacterial and Antibiotic-Potentiating Activities of Thirteen Cameroonian Edible Plants against Gram-Negative Resistant Phenotypes

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Paul Nayim ◽  
Armelle T. Mbaveng ◽  
Brice E. N. Wamba ◽  
Aimé G. Fankam ◽  
Joachim K. Dzotam ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
Multidrug Resistant ◽  
Bark Extract ◽  
Minimal Bactericidal Concentration ◽  
Edible Plants ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Microdilution Method ◽  
Multiresistant Bacteria ◽  
Broth Microdilution Method

This work was designed to investigate the antibacterial activities of methanol extracts from thirteen Cameroonian edible plants and their antibiotic-potentiating effects against Gram-negative multidrug-resistant (MDR) phenotypes. The broth microdilution method was used to evaluate the minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of the extracts, as well as their antibiotic-potentiating activities. The phytochemical screening of the extracts was carried out according to the standard methods. The results of phytochemical tests revealed the presence of sterols, polyphenols, and tannins in most of the tested extracts, with the other classes of secondary metabolites being selectively distributed. Tested extracts showed variable antibacterial activities with MIC values ranging from 64 to 1024 μg/mL. However, some extracts were significantly active against certain bacterial strains: seeds extract of Theobroma cacao (64 μg/mL) against Escherichia coli AG100Atet and Klebsiella pneumoniae K24, and the bark extract of Uapaca guineensis against E. coli ATCC 8739. The leaves extract of T. cacao displayed the best MBC values (256 μg/mL) against E. aerogenes EA27. Some tested extracts included extracts from the leaves of T. cacao and P. vulgaris, and the seeds of D. edulis and barks A. indica has selectively improved (2- to 64-fold) the antibacterial activities of some of the tested antibiotics, chloramphenicol (CHL), tetracycline (TET), kanamycin (KAN), streptomycin (STR), and erythromycin (ERY), against more than 70% of tested MDR bacteria. The findings of this work showed that tested plant extracts and particularly those from T. cacao and Phaseolus vulgaris can be used alone or in combination with conventional antibiotics in the treatment of infections involving multiresistant bacteria.

scholarly journals Ceftolozane-Tazobactam Activity against Pseudomonas aeruginosa Clinical Isolates from U.S. Hospitals: Report from the PACTS Antimicrobial Surveillance Program, 2012 to 2015

2017 ◽  
Vol 61 (7) ◽  
Author(s):  
Dee Shortridge ◽  
Mariana Castanheira ◽  
Michael A. Pfaller ◽  
Robert K. Flamm
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Bacterial Infections ◽  
Multidrug Resistant ◽  
Surveillance Program ◽  
Drug Resistant ◽  
Content Type ◽  
Microdilution Method ◽  
Antimicrobial Surveillance ◽  
Broth Microdilution Method

ABSTRACT The activity of ceftolozane-tazobactam was compared to the activities of 7 antimicrobials against 3,851 Pseudomonas aeruginosa isolates collected from 32 U.S. hospitals in the Program to Assess Ceftolozane-Tazobactam Susceptibility from 2012 to 2015. Ceftolozane-tazobactam and comparator susceptibilities were determined using the CLSI broth microdilution method at a central monitoring laboratory. For ceftolozane-tazobactam, 97.0% of the isolates were susceptible. Susceptibilities of the other antibacterials tested were: amikacin, 96.9%; cefepime, 85.9%; ceftazidime, 85.1%; colistin, 99.2%; levofloxacin, 76.6%; meropenem, 81.8%; and piperacillin-tazobactam, 80.4%. Of the 699 (18.1%) meropenem-nonsusceptible P. aeruginosa isolates, 87.6% were susceptible to ceftolozane-tazobactam. Six hundred seven isolates (15.8%) were classified as multidrug resistant (MDR), and 363 (9.4%) were classified as extensively drug resistant (XDR). Only 1 isolate was considered pandrug resistant, which was resistant to all tested agents, including colistin. Of the 607 MDR isolates, 84.9% were ceftolozane-tazobactam susceptible, and 76.9% of XDR isolates were ceftolozane-tazobactam susceptible. In vitro activity against drug-resistant P. aeruginosa indicates ceftolozane-tazobactam may be an important agent in treating serious bacterial infections.

scholarly journals Characterization of Three Porcine Acinetobacter towneri Strains Co-Harboring tet(X3) and blaOXA-58

2020 ◽  
Vol 10 ◽  
Author(s):  
Jiangang Ma ◽  
Juan Wang ◽  
Jie Feng ◽  
Yingqiu Liu ◽  
Baowei Yang ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Multidrug Resistant ◽  
S1 Nuclease ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Nuclease Digestion ◽  
Insertion Elements ◽  
Backbone Structure ◽  
Multiple Antibiotics

Tigecycline is the antibiotic of last resort for the treatment of extensively drug-resistant bacterial infections, mainly those of multidrug-resistant Gram-negative bacteria. The plasmid-mediated tet(X3) gene has recently been described in various pathogens that are resistant to tigecycline. We report three tigecycline-resistant Acinetobacter towneri strains isolated from porcine faeces in China, which all contained the tet(X3)-harboring plasmids. A broth microdilution method was used to examine the antimicrobial susceptibility of the isolates, and S1-Nuclease digestion pulsed-field gel electrophoresis (S1-PFGE) was used to characterize their plasmid profiles. The whole-genome sequences of the isolates were determined with the Nanopore PromethION platform. The sequence analysis indicated that the strains were A. towneri. They showed resistance to multiple antibiotics, and all the resistance genes were located on plasmids. The three tet(X3)-harboring plasmids had a similar backbone structure, and all contained blaOXA-58 with various insertion elements (IS). ISCR2 is considered an important factor in tet(X3) mobilization. In addition to ISCR2, we demonstrate that IS26 generates a circular intermediate containing the tet(X3) gene, which could increase the dissemination risk. To our knowledge, this is the first report of tet(X3)- and blaOXA-58-harboring plasmids in A. towneri. Because the IS26 is frequently found in front of tet(X3), research should be directed toward the action of IS26 in the spread of tet(X3).

scholarly journals GC-FID Analysis and Antibacterial Activity of the Calyptranthes concinna Essential Oil against MDR Bacterial Strains

Separations ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 10
Author(s):  
Maria do Socorro Costa ◽  
Nara Juliana Santos Araújo ◽  
Thiago Sampaio de Freitas ◽  
Francisco Assis Bezerra da Cunha ◽  
Wanderlei do Amaral ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Essential Oil ◽  
Inhibitory Concentration ◽  
Chemical Constituents ◽  
Antibiotic Activity ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Multiresistant Bacteria ◽  
Broth Microdilution Method ◽  
Mic Value

Presently, results from a study carried out in this area using the essential oil from the Calyptranthes concinna species, a representative from the Myrtaceae family, are reported. The essential oil was obtained by hydrodistillation and gas chromatography coupled to mass spectrometry was used to identify its chemical constituents. Antibacterial activity was determined using the broth microdilution method, thus obtaining the Minimal Inhibitory Concentration (MIC) value, from which the subinhibitory concentration (MIC/8) was derived. The C. concinna essential oil presented antibacterial activity against both standard and multiresistant bacteria. In addition, the oil demonstrated an antibiotic activity potentiation against Staphylococcus aureus and Escherichia coli when in combination with the antibiotic gentamicin, reducing the MIC from 141.38 μg/mL and 208.63 μg/mL to 64 μg/mL and 128 μg/mL, respectively. Conclusions: Findings from the present study suggest this oil is promising in terms of its antimicrobial activity.

Repurposing of escitalopram oxalate and clonazepam in combination with ciprofloxacin and sulfamethoxazole/trimethoprim for treatment of multidrug-resistant microorganisms and evaluation of the cleavage capacity of plasmid DNA

2021 ◽  
Author(s):  
Taciéli Fagundes da Rosa ◽  
Catrine de Souza Machado ◽  
Marissa Bolson Serafin ◽  
Angelita Bottega ◽  
Silvana Silveira Coelho ◽  
...  
Keyword(s):  
Plasmid Dna ◽  
Bacterial Infections ◽  
Bacterial Resistance ◽  
Inhibitory Concentration ◽  
Drug Repurposing ◽  
Multidrug Resistant ◽  
Culture Collection ◽  
Bacterial Strains ◽  
Gram Positive

Bacterial resistance has propelled one of the most serious public health problems in the world. In this sense, drug repurposing has emerged for faster identification of effective drugs. The aim of this study was to investigate the repurposing of escitalopram oxalate and clonazepam drugs individually and in combination with antibiotics ciprofloxacin and sulfamethoxazole-trimethoprim to treat multidrug-resistant microorganisms (MDR) and to evaluate the chemical nuclease capacity. The minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), fractional inhibitory concentration index (FICI) and tolerance level were determined against each microorganism tested. In vitro antibacterial activity was evaluated against forty-seven multidrug-resistant clinical isolates and eleven standard bacterial strains of the American Type Culture Collection (ATCC). Escitalopram oxalate was active mainly against Gram-positive and clonazepam against Gram-positive and Gram-negative bacteria. When associated with the two antibiotics mentioned, they had a significant synergistic effect. Clonazepam was able to cleave plasmid DNA and the mechanisms involved were oxidative and hydrolytic. These results allow us to suggest repurposing these non-antibiotic drugs to treat bacterial infections. However, further studies on the mechanism of action of these drugs should be performed, including to increase safety in use.

scholarly journals Silver (I) N-Heterocyclic Carbene Complexes: A Winning and Broad Spectrum of Antimicrobial Properties

2021 ◽  
Vol 22 (5) ◽  
pp. 2497
Author(s):  
Filippo Prencipe ◽  
Anna Zanfardino ◽  
Michela Di Napoli ◽  
Filomena Rossi ◽  
Stefano D’Errico ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Antimicrobial Agents ◽  
Antimicrobial Properties ◽  
Resistance Mechanisms ◽  
Heterocyclic Carbenes ◽  
Significant Activity ◽  
Bacterial Strains ◽  
Development Of Resistance ◽  
Starting Point ◽  
Catalytic Chemistry

The evolution of antibacterial resistance has arisen as the main downside in fighting bacterial infections pushing researchers to develop novel, more potent and multimodal alternative drugs.Silver and its complexes have long been used as antimicrobial agents in medicine due to the lack of silver resistance and the effectiveness at low concentration as well as to their low toxicities compared to the most commonly used antibiotics. N-Heterocyclic Carbenes (NHCs) have been extensively employed to coordinate transition metals mainly for catalytic chemistry. However, more recently, NHC ligands have been applied as carrier molecules for metals in anticancer applications. In the present study we selected from literature two NHC-carbene based on acridinescaffoldand detailed nonclassicalpyrazole derived mono NHC-Ag neutral and bis NHC-Ag cationic complexes. Their inhibitor effect on bacterial strains Gram-negative and positivewas evaluated. Imidazolium NHC silver complex containing the acridine chromophore showed effectiveness at extremely low MIC values. Although pyrazole NHC silver complexes are less active than the acridine NHC-silver, they represent the first example of this class of compounds with antimicrobial properties. Moreover all complexesare not toxic and they show not significant activity againstmammalian cells (Hek lines) after 4 and 24 h. Based on our experimental evidence, we are confident that this promising class of complexes could represent a valuable starting point for developing candidates for the treatment of bacterial infections, delivering great effectiveness and avoiding the development of resistance mechanisms.

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