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 Tristemma hirtumand Five Other Cameroonian Edible Plants with Weak or No Antibacterial Effects Modulate the Activities of Antibiotics against Gram-Negative Multidrug-Resistant Phenotypes

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Gaëlle S. Nguenang ◽  
Armelle T. Mbaveng ◽  
Aimé G. Fankam ◽  
Hermione T. Manekeng ◽  
Paul Nayim ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
Multidrug Resistant ◽  
Phytochemical Analysis ◽  
Edible Plants ◽  
Phytochemical Screening ◽  
Antibacterial Effects ◽  
Gram Negative ◽  
Microdilution Method ◽  
Raphia Hookeri

In order to contribute to the fight against infectious diseases, thein vitroantibacterial activity and the antibiotic-potentiating effects ofTristemma hirtumand five other Cameroonian edible plants have been evaluated against Gram-negative multidrug-resistant (MDR) phenotypes. The microdilution method was used to evaluate the bacterial susceptibility of the extracts and their combination to common antibiotics. The phytochemical screening of the extracts was carried out according to standard methods. Phytochemical analysis of the extracts revealed the presence of alkaloids, triterpenes, steroids, and polyphenols, including flavonoids in most of the tested extracts. The entire tested extracts showed moderate (512 μg/mL ≤ MIC ≤ 2048 μg/mL) to weak (MIC > 2048 μg/mL) antibacterial activities against the tested bacteria. Furthermore, extracts of leaf ofTristemma hirtumand pericarpsofRaphia hookeri(at their MIC/2 and MIC/4) strongly potentiated the activities of all antibiotics used in the study, especially those of chloramphenicol (CHL), ciprofloxacin (CIP), kanamycin (KAN), and tetracycline (TET) against 70% (7/10) to 100% (10/10) of the tested MDR bacteria, with the modulating factors ranging from 2 to 128. The results of this study suggest that extracts from leaves ofTristemma hirtumand pericarps ofRaphia hookerican be sources of plant-derived products with antibiotic modifying activity.

Synthesis and Antibacterial Activities of Amidine Substituted Monocyclic β-Lactams

2021 ◽  
Vol 17 ◽  
Author(s):  
Lijuan Zhai ◽  
Lili He ◽  
Yuanbai Liu ◽  
Ko Ko Myo ◽  
Zafar Iqbal ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
Antimicrobial Effect ◽  
Antibacterial Activities ◽  
Lead Target ◽  
Bacterial Strains ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Clinical Interest

Background: Mononcyclic β-lactams are regarded as the most resistant class of β-lactams against a series of β-lactamases though possess limited antibacterial activity. Aztreonam being the first clinically approved monobactam needs broad-spectrum efficacy through structural modification. Objective: We strive to synthesize a number of monocyclic β-lactams by varying the substituents at N1, C3 and C4 positions of azetidinone ring and study the antimicrobial effect on variable bacterial strains. Methods: Seven new monobactam derivatives 23a-g, containing substituted-amidine moieties linked to the azetidinone ring via thiazole linker, were synthesized through multistep synthesis. The final compounds were investigated for their in vitro antibacterial activities using broth microdilution method, against ten bacterial strains of clinical interest. The minimum inhibitory concentrations (MICs) of newly synthesized derivatives were compared with aztreonam, ceftazidime and meropenem, existing clinical antibiotics. Results: All compounds 23a-g showed higher antibacterial activities (MIC 0.25 µg/mL to 64 µg/mL) against tested strains as compared to aztreonam (MIC 16 µg/mL to >64 µg/mL) and ceftazidime (MIC >64 µg/mL). However all compounds, except 23d, exhibited lower antibacterial activity against all tested bacterial strains as compared to meropenem. Conclusion: Compound 23d showed comparable or improved antibacterial activity (MIC 0.25 µg/mL to 2 µg/mL) to meropenem (MIC 1 µg/mL to 2 µg/mL) in case of seven bacterial species. Therefore, compound 23d may be valuable lead target for further investigations against multi-drug resistant Gram-negative bacteria.

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 In VitroActivity of Plazomicin against Gram-Negative and Gram-Positive Bacterial Pathogens Isolated from Patients in Canadian Hospitals from 2013 to 2017 as Part of the CANWARD Surveillance Study

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Andrew Walkty ◽  
James A. Karlowsky ◽  
Melanie R. Baxter ◽  
Heather J. Adam ◽  
George G. Zhanel
Keyword(s):  
Antimicrobial Agents ◽  
Bacterial Pathogens ◽  
Multidrug Resistant ◽  
Surveillance Study ◽  
Gram Positive ◽  
Gram Negative ◽  
Content Type ◽  
Microdilution Method ◽  
Broth Microdilution Method

ABSTRACTThe Clinical and Laboratory Standards Institute (CLSI) broth microdilution method was used to evaluate thein vitroactivities of plazomicin and comparator antimicrobial agents against 7,712 Gram-negative and 4,481 Gram-positive bacterial pathogens obtained from 2013 to 2017 from patients in Canadian hospitals as part of the CANWARD Surveillance Study. Plazomicin demonstrated potentin vitroactivity againstEnterobacteriaceae(MIC90≤ 1 µg/ml for all species tested exceptProteus mirabilisandMorganella morganii), including aminoglycoside-nonsusceptible, extended-spectrum β-lactamase (ESBL)-positive, and multidrug-resistant (MDR) isolates. Plazomicin was equally active against methicillin-susceptible and methicillin-resistant isolates ofStaphylococcus aureus.

Chemical composition and antimicrobial activity of Erodium species: E. ciconium L., E. cicutarium L., and E. absinthoides Willd. (Geraniaceae)

2010 ◽  
Vol 64 (3) ◽  
Author(s):  
Zorica Stojanović-Radić ◽  
Ljiljana Čomić ◽  
Niko Radulović ◽  
Milan Dekić ◽  
Vladimir Ranđelović ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Chemical Composition ◽  
Essential Oils ◽  
Palmitic Acid ◽  
Gram Negative Bacteria ◽  
Broth Microdilution ◽  
Bacterial Strains ◽  
Gram Negative ◽  
Microdilution Method ◽  
Broth Microdilution Method

AbstractThe present study gives results of chemical composition analyses and antimicrobial activity testing of three Erodium species: E. ciconium L., E. cicutarium L., and E. absinthoides Willd. Essential oils were obtained by hydro-distillation from air-dried entire plants and analyzed by GC and GC-MS. A total of 209 different compounds were identified: 162 for E. cicutarium, 107 for E. ciconium, and 79 for E. absinthoides. Antimicrobial activity (broth microdilution method) of the oils was screened against a panel of Gram positive and Gram negative bacteria and a number of fungi. Moderate susceptibility of all tested strains was observed. Determined MIC values were 0.156–5 mg mL−1 (bacterial strains) and 0.039–0.325 mg mL−1 (fungal strains). Major component of the most active oil, palmitic acid, was also tested for activity together with stearic and myristic acids.

scholarly journals Cefepime-Zidebactam (WCK 5222) Activity Tested against Gram-negative Organisms Causing Bloodstream Infections Worldwide

2017 ◽  
Vol 4 (suppl_1) ◽  
pp. S374-S375 ◽  
Author(s):  
Helio S Sader ◽  
Mariana Castanheira ◽  
Jennifer M Streit ◽  
Leonard R Duncan ◽  
Robert K Flamm
Keyword(s):  
Bloodstream Infections ◽  
Multidrug Resistant ◽  
Vitro Activity ◽  
Asia Pacific ◽  
In Vitro Activity ◽  
Gram Negative ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Research Grant

Abstract Background Zidebactam (ZID), a bicyclo-acyl hydrazide, is a β-lactam enhancer with a dual mechanism of action involving selective and high binding affinity to Gram-negative (GN) PBP2 and β-lactamase inhibition. We evaluated the in vitro activity of cefepime (FEP) combined with ZID against GN organisms causing bloodstream infections (BSI) in hospitals worldwide. Methods A total of 2,094 isolates from 105 medical centers were evaluated. Isolates were collected from Europe (1,050), USA (331), Latin America (LA; 200) and the Asia-Pacific region (AP; 393) in 2015, and China (120) in 2013 by the SENTRY Program. Susceptibility (S) testing was performed by reference broth microdilution method against FEP-ZID (1:1 ratio) and comparators. The collection included 1,809 Enterobacteriaceae (ENT), 170 P. aeruginosa (PSA) and 115 Acinetobacter spp. (ASP). Results FEP-ZID was very active against ENT (MIC50/90 of ≤0.03/0.12 μg/mL) with 99.9 and 100.0% of isolates inhibited at ≤4/4 and ≤8/8 μg/mL, respectively, and retained potent activity against carbapenem-resistant (CRE; n = 44; MIC50/90, 1/4 μg/mL), multidrug-resistant (MDR), and extensively drug-resistant (XDR) isolates (Table). Amikacin (AMK; MIC50/90, 2/4 μg/mL; 97.7% S) was also very active against ENT, and colistin (COL; MIC50/90, 0.12/>8 μg/mL) inhibited only 87.3% of isolates at ≤2 μg/mL. FEP-ZID was highly active against PSA, including isolates resistant to other antipseudomonal β-lactams, MDR (MIC50/90, 4/8 μg/mL) and XDR (MIC50/90, 4/8 μg/mL) isolates. Among the comparators, COL (MIC50/90 of ≤0.5/1 μg/mL; 100.0% S) and AMK (MIC50/90, 4/16 μg/mL; 91.2% S) were the most active agents against PSA. FEP-ZID (MIC50/90, 16/32 μg/mL) was 4-fold more active than FEP against ASP. Conclusion FEP-ZID (WCK 5222) exhibited potent in vitro activity against a large worldwide collection of GN isolates from BSI, including MDR and XDR isolates. These results support further clinical development of WCK 5222 for treating BSI. Disclosures H. S. Sader, Wockhardt Bio Ag: Research Contractor, Research grant; M. Castanheira, Wockhardt Bio Ag: Research Contractor, Research grant; J. M. Streit, Wockhardt Bio Ag: Research Contractor, Research grant; L. R. Duncan, Wockhardt Bio Ag: Research Contractor, Research grant; R. K. Flamm, Wock: Research Contractor, Research support

scholarly journals Antibacterial activities of selected edible plants extracts against multidrug-resistant Gram-negative bacteria

2013 ◽  
Vol 13 (1) ◽  
Author(s):  
Doriane E Djeussi ◽  
Jaurès AK Noumedem ◽  
Jackson A Seukep ◽  
Aimé G Fankam ◽  
Igor K Voukeng ◽  
...  
Keyword(s):  
Antibacterial Activities ◽  
Multidrug Resistant ◽  
Gram Negative Bacteria ◽  
Edible Plants ◽  
Gram Negative

scholarly journals Antistaphylococcal and Antibiotic Resistance Modulatory Activities of Thirteen Cameroonian Edible Plants against Resistant Phenotypes

2018 ◽  
Vol 2018 ◽  
pp. 1-12
Author(s):  
Brice E. N. Wamba ◽  
Armelle T. Mbaveng ◽  
Paul Nayim ◽  
Joachim K. Dzotam ◽  
Ornella J. T. Ngalani ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Efflux Pump ◽  
Efflux Pumps ◽  
Antibacterial Activities ◽  
Multidrug Resistant ◽  
Edible Plants ◽  
Bacterial Strains ◽  
Efflux Pump Inhibitor ◽  
Dacryodes Edulis

Background. In this study, 18 methanol extracts from Cameroonian edible plants were tested for their antibacterial activities against 26 strains ofS. aureus; the role of efflux pumps in the resistance of tested bacteria and the antibiotic resistance-modulating activities against selected multidrug-resistant (MDR) phenotypes were also investigated.Methods. Broth microdilution assay was used to evaluate the antibacterial activity, the role of efflux pumps, and the antibiotic resistance-modulating effects of plant extracts.Results. Extracts fromDacryodes edulisseeds (DES) andDacryodes edulisbark (DEB) were active against all 26 tested bacterial strains, within the minimal inhibitory concentration (MIC) range of 256–1024 µg/mL. MIC values varied from 64 to 1024 µg/mL against 96.2% of the 26 tested bacteria forPhaseolus vulgarisleaves (PVL), 92.3% forAzadirachta indicabark (AIB),Dacryodes edulisleaves (DEL), andRicinodendron heudelotiileaves (RHL). The lowest MIC value of 64 µg/mL was obtained with the extract fromCucurbita maximabeans (CMB) against MRSA4 strain and fromUapaca guineensisbark (UGB) against MRSA9 strain. Bacterial efflux pump inhibitor (EPI), carbonyl cyanidem-chlorophenyl hydrazone (CCCP), improved the activity of DES and UGB as well as that of extracts fromHibiscus esculentusleaves (HEL) andUapaca guineensisleaves (UGL) against resistantS. aureusstrains. Antibiotic-modulating effects against more than 70% of theS. aureusstrains tested were obtained when RHL (at MIC/2) was combined with CIP, ERY, and KAN (88.89%), CHL (88.89%), TET (77.78%), and STR (88.89%).Conclusion. The present study demonstrated that the 13 tested plants had antistaphylococcal effects and that DES, HEL, UGL, and UGB could be used in combination with EPI to combat resistance toStaphylococcus aureus. Also, it demonstrated that some studied extracts and mostly RHL could be used as antibiotic resistance modulators to fight against resistant strains ofS. aureus.

scholarly journals Activity of the Novel Peptide Arminin against Multiresistant Human Pathogens Shows the Considerable Potential of Phylogenetically Ancient Organisms as Drug Sources

2009 ◽  
Vol 53 (12) ◽  
pp. 5245-5250 ◽  
Author(s):  
René Augustin ◽  
Friederike Anton-Erxleben ◽  
Stephanie Jungnickel ◽  
Georg Hemmrich ◽  
Björn Spudy ◽  
...  
Keyword(s):  
Antimicrobial Peptide ◽  
Multidrug Resistant ◽  
Proteolytic Processing ◽  
Erythrocyte Membranes ◽  
Resistant Bacteria ◽  
Minimal Bactericidal Concentration ◽  
Human Pathogens ◽  
Bacterial Strains ◽  
Multiresistant Bacteria ◽  
High Level

ABSTRACT The emergence of multidrug-resistant bacteria highlights the need for new antibacterial agents. Arminin 1a is a novel antimicrobial peptide discovered during investigations of the epithelial defense of the ancient metazoan Hydra. Following proteolytic processing, the 31-amino-acid-long positively charged C-terminal part of arminin 1a exhibits potent and broad-spectrum activity against bacteria, including multiresistant human pathogenic strains, such as methicillin-resistant Staphylococcus aureus (MRSA) strains (minimal bactericidal concentration, 0.4 μM to 0.8 μM). Ultrastructural observations indicate that bacteria are killed by disruption of the bacterial cell wall. Remarkably, the antibacterial activity of arminin 1a is not affected under the physiological salt conditions of human blood. In addition, arminin 1a is a selective antibacterial agent that does not affect human erythrocyte membranes. Arminin 1a shows no sequence homology to any known antimicrobial peptide. Because of its high level of activity against multiresistant bacterial strains pathogenic for humans, the peptide arminin 1a is a promising template for a new class of antibiotics. Our data suggest that ancient metazoan organisms such as Hydra hold promise for the detection of novel antimicrobial molecules and the treatment of infections caused by multiresistant bacteria.

scholarly journals 1598. Antimicrobial Activity of the Novel β-Lactam Enhancer Combination Cefepime–Zidebactam (WCK-5222) Tested Against Gram-Negative Bacteria Isolated in United States Medical Centers from Patients with Bloodstream Infections

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S583-S583
Author(s):  
Mariana Castanheira ◽  
Michael D Huband ◽  
Robert K Flamm ◽  
Helio S Sader
Keyword(s):  
Bloodstream Infections ◽  
Multidrug Resistant ◽  
High Dose ◽  
Gram Negative ◽  
Highly Active ◽  
Microdilution Method ◽  
Medical Centers ◽  
Carbapenem Resistant ◽  
Broth Microdilution Method ◽  
Dual Mechanism

Abstract Background Zidebactam (ZID) is a β-lactam enhancer antibiotic with a dual mechanism of action: high binding affinity to gram-negative PBP2 and β-lactamase (BL) inhibition. We evaluated the activity of cefepime (FEP) combined with ZID against contemporary clinical isolates of gram-negative bacilli (GNB) causing bloodstream infections (BSIs) in the US hospitals. Methods 1,239 GNB were consecutively collected (1/patient) from 34 US medical centers in 2018. Susceptibility (S) testing against FEP-ZID (1:1 ratio) and comparators were performed by reference broth microdilution method in a central laboratory. The FEP S breakpoint of ≤ 8 mg/L (CLSI, high dose) was applied to FEP-ZID for comparison purposes. An FEP-ZID S breakpoint of ≤ 64 mg/L has been proposed for non-fermentative GNB based on pharmacokinetic/pharmacodynamic target attainment and was also applied. Selected Enterobacterales (ENT) isolates were evaluated by whole-genome sequencing. Results FEP-ZID was highly active against ENT (MIC50/MIC90, 0.03/0.12 mg/L; highest MIC, 4 mg/L; Table), including multidrug-resistant (MDR, MIC50/MIC90, 0.12/0.25 mg/L) and carbapenem-resistant isolates (n = 7; MIC50, 0.5 mg/L). The highest FEP-ZID MIC values among E. coli, K. pneumoniae, and E. cloacae were 1, 2, and 0.25 mg/L, respectively. The most active comparators tested against MDR ENT were ceftazidime–avibactam (CAZ-AVI; MIC50/MIC90, 0.25/1 mg/L; 98.0%S), meropenem (MEM; MIC50/MIC90, 0.03/0.12 mg/L; 93.1%S) and amikacin (AMK; MIC50/MIC90, 4/16 mg/L; 92.1%S). The most active agents tested against P. aeruginosa were FEP-ZID (MIC50/MIC90, 1/4 mg/L; highest MIC, 8 mg/L), colistin (MIC50/MIC90, 0.5/1 mg/L; 100.0%S), and AMK (MIC50/MIC90, 4/8 mg/L; 99.2%S); whereas CAZ-AVI and ceftolozane–tazobactam were active against 96.5–96.7% of isolates. FEP-ZID exhibited good activity against Acinetobacter spp. (MIC50/MIC90, 2/8 mg/L) and S. maltophilia (MIC50/MIC90, 4/32 mg/L). S. maltophilia displayed low S rates to most comparators. Conclusion FEP-ZID demonstrated potent activity against a large collection GNB from BSI, including isolates resistant to other BL inhibitor combinations and/or carbapenems. These results support further clinical development of FEP-ZID. Disclosures All authors: No reported disclosures.

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