scholarly journals In Vitro Antimicrobial Activity and Mutant Prevention Concentration of Colistin against Acinetobacter baumannii

2010 ◽  
Vol 54 (9) ◽  
pp. 3998-3999 ◽  
Author(s):  
Yun Cai ◽  
Ran Li ◽  
Beibei Liang ◽  
Nan Bai ◽  
Youning Liu ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Plasma Concentration ◽  
Combination Therapy ◽  
Acinetobacter Baumannii ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Recommended Dosage ◽  
Mutant Prevention Concentration ◽  
Emergence Of Resistance

ABSTRACT The antimicrobial activities of colistin and other antibiotics against clinical Acinetobacter baumannii and the mutant prevention concentration (MPC) of colistin against multidrug-resistant A. baumannii were studied. All 70 stains tested were sensitive to colistin. The MPC range of colistin against 30 multidrug-resistant A. baumannii stains was approximately 32 to >128 μg/ml, and the MPC at which 90% of the isolates tested were prevented (MPC90) exceeded 128 μg/ml, which was much higher than the plasma concentration of colistin at the current recommended dosage. So, combination therapy for colistin treatment of A. baumannii would be prudent to slow the emergence of resistance.

scholarly journals The Pomegranate: Effects on Bacteria and Viruses That Influence Human Health

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Amy B. Howell ◽  
Doris H. D'Souza
Keyword(s):  
Antimicrobial Activity ◽  
Foodborne Pathogens ◽  
Clinical Results ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Oral Bacteria ◽  
Resistant Bacteria ◽  
Wide Range

Pomegranates have been known for hundreds of years for their multiple health benefits, including antimicrobial activity. The recent surge in multidrug-resistant bacteria and the possibility of widespread global virus pandemics necessitate the need for additional preventative and therapeutic options to conventional drugs. Research indicates that pomegranates and their extracts may serve as natural alternatives due to their potency against a wide range of bacterial and viral pathogens. Nearly every part of the pomegranate plant has been tested for antimicrobial activities, including the fruit juice, peel, arils, flowers, and bark. Many studies have utilized pomegranate peel with success. There are various phytochemical compounds in pomegranate that have demonstrated antimicrobial activity, but most of the studies have found that ellagic acid and larger hydrolyzable tannins, such as punicalagin, have the highest activities. In some cases the combination of the pomegranate constituents offers the most benefit. The positive clinical results on pomegranate and suppression of oral bacteria are intriguing and worthy of further study. Much of the evidence for pomegranates’ antibacterial and antiviral activities against foodborne pathogens and other infectious disease organisms comes fromin vitrocell-based assays, necessitating further confirmation ofin vivoefficacy through human clinical trials.

scholarly journals Pharmacodynamic evaluation of suppression of in vitro resistance in Acinetobacter baumannii strains using polymyxin B-based combination therapy

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nayara Helisandra Fedrigo ◽  
Danielle Rosani Shinohara ◽  
Josmar Mazucheli ◽  
Sheila Alexandra Belini Nishiyama ◽  
Floristher Elaine Carrara-Marroni ◽  
...  
Keyword(s):  
Plasma Concentration ◽  
Combination Therapy ◽  
Polymyxin B ◽  
Dosage Interval ◽  
Combination Regimen ◽  
Mutant Selection ◽  
Selection Window ◽  
Mutant Prevention Concentration ◽  
Free Plasma

AbstractThe emergence of polymyxin resistance in Gram-negative bacteria infections has motivated the use of combination therapy. This study determined the mutant selection window (MSW) of polymyxin B alone and in combination with meropenem and fosfomycin against A. baumannii strains belonging to clonal lineages I and III. To evaluate the inhibition of in vitro drug resistance, we investigate the MSW-derived pharmacodynamic indices associated with resistance to polymyxin B administrated regimens as monotherapy and combination therapy, such as the percentage of each dosage interval that free plasma concentration was within the MSW (%TMSW) and the percentage of each dosage interval that free plasma concentration exceeded the mutant prevention concentration (%T>MPC). The MSW of polymyxin B varied between 1 and 16 µg/mL for polymyxin B-susceptible strains. The triple combination of polymyxin B with meropenem and fosfomycin inhibited the polymyxin B-resistant subpopulation in meropenem-resistant isolates and polymyxin B plus meropenem as a double combination sufficiently inhibited meropenem-intermediate, and susceptible strains. T>MPC 90% was reached for polymyxin B in these combinations, while %TMSW was 0 against all strains. TMSW for meropenem and fosfomycin were also reduced. Effective antimicrobial combinations significantly reduced MSW. The MSW-derived pharmacodynamic indices can be used for the selection of effective combination regimen to combat the polymyxin B-resistant strain.

scholarly journals In VitroPharmacodynamics of Polymyxin B and Tigecycline Alone and in Combination against Carbapenem-Resistant Acinetobacter baumannii

2013 ◽  
Vol 58 (2) ◽  
pp. 874-879 ◽  
Author(s):  
Mao Hagihara ◽  
Seth T. Housman ◽  
David P. Nicolau ◽  
Joseph L. Kuti
Keyword(s):  
Combination Therapy ◽  
Acinetobacter Baumannii ◽  
Population Analysis ◽  
Polymyxin B ◽  
Multidrug Resistant ◽  
Bacterial Killing ◽  
Content Type ◽  
Model Free ◽  
Carbapenem Resistant

ABSTRACTCarbapenem-resistantAcinetobacter baumanniiis increasing in prevalence. Polymyxin B and tigecycline are among the most active antibiotics used against this pathogenin vitro. Pastin vitrostudies, however, neglected the importance of simulating exposures observed in humans to determine their antibacterial effects. In this study, four carbapenem-resistantA. baumanniiisolates were evaluated using anin vitropharmacodynamic model. Free-drug exposures using 1 mg/kg of body weight of polymyxin B every 12 h (q12h), 100 and 200 mg tigecycline q12h, and the combination of these regimens were simulated. The microbiological responses to these treatments were measured by the change in log10CFU/ml over 24 h and the area under the bacterial killing and regrowth curve (AUBC). Resistance was assessed by a population analysis profile (PAP) conducted after 24 h of treatment. Polymyxin B achieved a reduction on the order of −2.05 ± 0.68 log10CFU/ml against theseA. baumanniiisolates, while all isolates grew to control levels with tigecycline monotherapy. Combination therapy with polymyxin B plus 200 mg tigecycline q12h achieved a greater reduction in bacterial density than did therapy with polymyxin B alone (−3.31 ± 0.71 versus −2.05 ± 0.68 log10CFU/ml,P< 0.001) but not significantly different than combination therapy with 100 mg tigecycline q12h (−2.45 ± 1.00 log10CFU/ml,P= 0.370). Likewise, combination therapy with polymyxin B plus 200 mg tigecycline q12h significantly reduced the AUBC compared to that with polymyxin B alone (62.8 ± 8.9 versus 79.4 ± 10.5 log10CFU/ml,P< 0.05). No changes in the PAP from baseline were observed for either antibiotic alone. In this study, combination therapy with simulated exposures of polymyxin B and tigecycline at an aggressive dose of 200 mg q12h produced synergistic or additive effects on humans against these multidrug-resistantA. baumanniistrains.

scholarly journals Antimicrobial Activity of Nanoemulsion in Combination with Cetylpyridinium Chloride in Multidrug-Resistant Acinetobacter baumannii

2013 ◽  
Vol 57 (8) ◽  
pp. 3568-3575 ◽  
Author(s):  
Yoon Y. Hwang ◽  
Karthikeyan Ramalingam ◽  
Diane R. Bienek ◽  
Valerie Lee ◽  
Tao You ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Acinetobacter Baumannii ◽  
Cetylpyridinium Chloride ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Antibiofilm Activity ◽  
Antibiotic Resistant ◽  
Content Type ◽  
A Cell ◽  
Triton X

ABSTRACTAcinetobacter baumanniihas emerged as a serious problematic pathogen due to the ever-increasing presence of antibiotic resistance, demonstrating a need for novel, broad-spectrum antimicrobial therapeutic options. Antimicrobial nanoemulsions are emulsified mixtures of detergent, oil, and water (droplet size, 100 to 800 nm) which have broad antimicrobial activity against bacteria, enveloped viruses, and fungi. Here, we screened the antimicrobial activities of five nanoemulsion preparations against fourAcinetobacter baumanniiisolates to identify the most suitable preparation for further evaluation. Among them, N5, which contains 10% (vol/vol) Triton X-100, 25% (vol/vol) soybean oil, and 1% (wt/vol) cetylpyridinium chloride (CPC), showed the best efficacy againstA. baumanniiin both its planktonic and biofilm forms and was selected for further study. Our data demonstrate that, while the killing of planktonic forms ofA. baumanniiwas due to the 1% CPC component of our nanoemulsions, the breakdown of biofilms was achieved via the emulsified oil and detergent fractions. Furthermore, we documented the effect of ethanol and NaCl in combination with N5 on planktonicA. baumannii. In killing curves of N5 combined with other agents (ethanol or NaCl), a synergistic effect of a ≥2-log decrease in CFU/ml was observed. The antibiofilm activity of N5 was confirmed via a cell proliferation test and scanning electron microscopy. The effects of exposure to severe environmental conditions, which simulates the field conditions in Iraq and Afghanistan, were evaluated, and this exposure did not affect the overall antimicrobial activity of N5. These studies lay a solid foundation for the utilization of nanoemulsions against the antibiotic-resistant forms ofA. baumannii.

scholarly journals In Vitro Evaluation of Antimicrobial Activity and Cytotoxicity of Different Nanobiotics Targeting Multidrug Resistant and Biofilm Forming Staphylococci

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Mennatallah A. Mohamed ◽  
Maha Nasr ◽  
Walid F. Elkhatib ◽  
Wafaa N. Eltayeb
Keyword(s):  
Antimicrobial Activity ◽  
Rat Hepatocytes ◽  
Antibacterial Activities ◽  
Multidrug Resistant ◽  
Antimicrobial Activities ◽  
Antibiotic Resistant ◽  
Diphenyltetrazolium Bromide ◽  
New Antibiotics ◽  
Conventional Antibiotics

Antibiotic-resistant and biofilm-forming bacteria have surprisingly increased over recent years. On the contrary, the rate of development of new antibiotics to treat these emerging superbugs is very slow. Therefore, the aim of this study was to prepare novel nanobiotic formulations to improve the antimicrobial activity of three antibiotics (linezolid, doxycycline, and clindamycin) against Staphylococci. Antibiotics were formulated as nanoemulsions and evaluated for their antimicrobial activities and cytotoxicities. Cytotoxicity of the conventional antibiotics and nanobiotics was analyzed using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on rat hepatocytes. Half-maximal inhibitory concentration (IC50) was estimated from an experimentally derived dose-response curve for each concentration using GraphPad Prism software. Upon quantitative assessment of Staphylococcus biofilm formation, eighty-four isolates (66.14 %) were biofilm forming. Linezolid and doxycycline nanobiotics exhibited promising antibacterial activities. On the contrary, clindamycin nanobiotic exhibited poor antibacterial activity. Minimum biofilm inhibitory concentrations showed that 73.68 %, 45.6%, and 5.2% of isolates were sensitive to linezolid, doxycycline, and clindamycin nanobiotics, respectively. Results of this study revealed that antibiotics loaded in nanosystems had a higher antimicrobial activity and lower cytotoxicities as compared to those of conventional free antibiotics, indicating their potential therapeutic values.

scholarly journals In vitro antimicrobials activity against endemic Acinetobacter baumannii multiresistant clones

2010 ◽  
Vol 4 (03) ◽  
pp. 164-167 ◽  
Author(s):  
Carlos Hernan Rodriguez ◽  
Alejandra De Ambrosio ◽  
Milena Bajuk ◽  
Mariela Spinozzi ◽  
Marcela Nastro ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Buenos Aires ◽  
Multidrug Resistant ◽  
University Hospital ◽  
Pfge Type ◽  
The World ◽  
Resistant Strains ◽  
Resistant Mutants ◽  
Emergence Of Resistance

Background: Multidrug-resistant strains of Acinetobacter baumannii have been reported increasingly around the world. The administration of an association of antibiotics has been proposed to create an active combination and to prevent the emergence of resistance. Methodology: The activity of colistin, rifampicin, gentamicin, imipenem and their associations was evaluated by means of killing curves in fourteen isolates belonging to three endemic PFGE types, in a university hospital of Buenos Aires city. The 14 isolates were selected on the basis of different mechanisms responsible for resistance to carbapenems and different susceptibility to colistin. Results: The mechanism responsible for the resistance to imipenem was the production of OXA-23 and OXA-58 carbapenemases. Heteroresistance to colistin was observed in six isolates. The associations colistin-rifampicin and colistin-imipenem were synergistic in heteroresistant isolates and prevented the development of colistin-resistant mutants. The association imipenem-gentamicin was bactericidal in gentamicin susceptible isolates, whereas the association imipenem-rifampicin was always indifferent. Conclusion: The antimicrobial activity and the presence of synergy are related to the antimicrobials' susceptibilities irrespective of the PFGE type or the OXA-carbapenemase produced.

scholarly journals In vitro assessment of cefoperazone-sulbactam based combination therapy for multidrug-resistant Acinetobacter baumannii isolates in China

2018 ◽  
Vol 10 (3) ◽  
pp. 1370-1376 ◽  
Author(s):  
Tao Li ◽  
Meiyan Sheng ◽  
Tengzhen Gu ◽  
Yan Zhang ◽  
Ailiyaer Yirepanjiang ◽  
...  
Keyword(s):  
Combination Therapy ◽  
Acinetobacter Baumannii ◽  
Multidrug Resistant ◽  
In Vitro Assessment
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