scholarly journals Pharmacodynamics of Minocycline against Acinetobacter baumannii in a Rat Pneumonia Model

2018 ◽  
Vol 63 (2) ◽  
pp. e01671-18
Author(s):  
Ziad Tarazi ◽  
Mojgan Sabet ◽  
Michael N. Dudley ◽  
David C. Griffith
Keyword(s):  
United States ◽  
Acinetobacter Baumannii ◽  
Antibacterial Effect ◽  
The United States ◽  
Bacteriostatic Effect ◽  
Time Curve ◽  
Bacterial Killing ◽  
Content Type ◽  
Concentration Time ◽  
Dosage Regimens

ABSTRACT Minocycline is currently approved in the United States for the treatment of infections caused by susceptible isolates of Acinetobacter spp. The objective of these studies was to determine the minocycline exposures associated with an antibacterial effect against Acinetobacter baumannii in a rat pneumonia model. Rats received minocycline doses as 30-min intravenous infusions. In the rat pneumonia model, six clinical isolates of A. baumannii with MICs ranging from 0.03 to 4 mg/liter were studied. In this model, minocycline produced a bacteriostatic effect with a free 24-h area under the concentration-time curve (AUC)/MIC ratio of 10 to 16 and produced 1 log of bacterial killing with a free 24-h AUC/MIC of 13 to 24. These exposures can be achieved with the current FDA-approved dosage regimens of intravenous minocycline.

scholarly journals Corrected Genome Sequence of Acinetobacter baumannii Strain AB0057, an Antibiotic-Resistant Isolate from Lineage 1 of Global Clone 1

2017 ◽  
Vol 5 (35) ◽  
Author(s):  
Mohammad Hamidian ◽  
Pratap Venepally ◽  
Ruth M. Hall ◽  
Mark D. Adams
Keyword(s):  
United States ◽  
Acinetobacter Baumannii ◽  
Genome Sequence ◽  
The United States ◽  
Targeted Sequencing ◽  
Resistant Isolate ◽  
Illumina Hiseq ◽  
Antibiotic Resistant ◽  
Content Type ◽  
Pcr Products

ABSTRACT Extensively antibiotic-resistant Acinetobacter baumannii isolate AB0057 recovered in the United States in 2004 was one of the first global clone 1 isolates to be completely sequenced. Here, the complete 4.05-Mb genome sequence (chromosome and one plasmid) has been revised using Illumina HiSeq data and targeted sequencing of PCR products.

scholarly journals Meropenem Combined with Ciprofloxacin Combats Hypermutable Pseudomonas aeruginosa from Respiratory Infections of Cystic Fibrosis Patients

2018 ◽  
Vol 62 (11) ◽  
Author(s):  
Vanessa E. Rees ◽  
Rajbharan Yadav ◽  
Kate E. Rogers ◽  
Jürgen B. Bulitta ◽  
Veronika Wirth ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Time Course ◽  
Respiratory Infections ◽  
Resistant Bacteria ◽  
Infection Model ◽  
Time Curve ◽  
Bacterial Killing ◽  
Content Type ◽  
Concentration Time

ABSTRACT Hypermutable Pseudomonas aeruginosa organisms are prevalent in chronic respiratory infections and have been associated with reduced lung function in cystic fibrosis (CF); these isolates can become resistant to all antibiotics in monotherapy. This study aimed to evaluate the time course of bacterial killing and resistance of meropenem and ciprofloxacin in combination against hypermutable and nonhypermutable P. aeruginosa. Static concentration time-kill experiments over 72 h assessed meropenem and ciprofloxacin in mono- and combination therapies against PAO1 (nonhypermutable), PAOΔmutS (hypermutable), and hypermutable isolates CW8, CW35, and CW44 obtained from CF patients with chronic respiratory infections. Meropenem (1 or 2 g every 8 h [q8h] as 3-h infusions and 3 g/day as a continuous infusion) and ciprofloxacin (400 mg q8h as 1-h infusions) in monotherapies and combinations were further evaluated in an 8-day hollow-fiber infection model study (HFIM) against CW44. Concentration-time profiles in lung epithelial lining fluid reflecting the pharmacokinetics in CF patients were simulated and counts of total and resistant bacteria determined. All data were analyzed by mechanism-based modeling (MBM). In the HFIM, all monotherapies resulted in rapid regrowth with resistance at 48 h. The maximum daily doses of 6 g meropenem (T>MIC of 80% to 88%) and 1.2 g ciprofloxacin (area under the concentration-time curve over 24 h in the steady state divided by the MIC [AUC/MIC], 176), both given intermittently, in monotherapy failed to suppress regrowth and resulted in substantial emergence of resistance (≥7.6 log10 CFU/ml resistant populations). The combination of these regimens achieved synergistic killing and suppressed resistance. MBM with subpopulation and mechanistic synergy yielded unbiased and precise curve fits. Thus, the combination of 6 g/day meropenem plus ciprofloxacin holds promise for future clinical evaluation against infections by susceptible hypermutable P. aeruginosa.

scholarly journals Multicenter Performance Assessment of Carba NP Test

2017 ◽  
Vol 55 (6) ◽  
pp. 1954-1960 ◽  
Author(s):  
Scott A. Cunningham ◽  
Brandi Limbago ◽  
Maria Traczewski ◽  
Karen Anderson ◽  
Meredith Hackel ◽  
...  
Keyword(s):  
United States ◽  
Performance Assessment ◽  
Acinetobacter Baumannii ◽  
The United States ◽  
Gram Negative ◽  
Content Type ◽  
Testing Laboratories ◽  
Blinded Manner ◽  
High Level ◽  
Site Versus

ABSTRACT Eighty Gram-negative bacilli (54 Enterobacteriaceae and 26 nonfermenting Gram-negative bacilli) obtained from multiple institutions in the United States were distributed in a blinded manner to seven testing laboratories to compare their performance of a test for detection of carbapenemase production, the Carba NP test. The Carba NP test was performed by all laboratories, following the Clinical and Laboratory Standards Institute (CLSI) procedure. Site-versus-site comparisons demonstrated a high level of consistency for the Carba NP assay, with just 3/21 site comparisons yielding a difference in sensitivity ( P < 0.05). Previously described limitations with bla OXA-48-like carbapenemases and bla OXA carbapenemases associated with Acinetobacter baumannii were noted. Based on these data, we demonstrate that the Carba NP test, when implemented with the standardized CLSI methodology, provides reproducible results across multiple sites for detection of carbapenemases.

scholarly journals Colistin and Polymyxin B Dosage Regimens against Acinetobacter baumannii: Differences in Activity and the Emergence of Resistance

2016 ◽  
Vol 60 (7) ◽  
pp. 3921-3933 ◽  
Author(s):  
Soon-Ee Cheah ◽  
Jian Li ◽  
Brian T. Tsuji ◽  
Alan Forrest ◽  
Jürgen B. Bulitta ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Public Health Problem ◽  
Polymyxin B ◽  
Major Public Health Problem ◽  
Bacterial Killing ◽  
Bacterial Populations ◽  
Content Type ◽  
Dosage Regimens ◽  
Drug Concentrations ◽  
The Impact

ABSTRACTInfections caused by multidrug-resistantAcinetobacter baumanniiare a major public health problem, and polymyxins are often the last line of therapy for recalcitrant infections by such isolates. The pharmacokinetics of the two clinically used polymyxins, polymyxin B and colistin, differ considerably, since colistin is administered as an inactive prodrug that undergoes slow conversion to colistin. However, the impact of these substantial pharmacokinetic differences on bacterial killing and resistance emergence is poorly understood. We assessed clinically relevant polymyxin B and colistin dosage regimens against one reference and three clinicalA. baumanniistrains in a dynamic one-compartmentin vitromodel. A new mechanism-based pharmacodynamic model was developed to describe and predict the drug concentrations and viable counts of the total and resistant populations. Rapid attainment of target concentrations was shown to be critical for polymyxin-induced bacterial killing. All polymyxin B regimens achieved peak concentrations of at least 1 mg/liter within 1 h and caused ≥4 log10killing at 1 h. In contrast, the slow rise of colistin concentrations to 3 mg/liter over 48 h resulted in markedly reduced bacterial killing. A significant (4 to 6 log10CFU/ml) amplification of resistant bacterial populations was common to all dosage regimens. The developed mechanism-based model explained the observed bacterial killing, regrowth, and resistance. The model also implicated adaptive polymyxin resistance as a key driver of bacterial regrowth and predicted the amplification of preexisting, highly polymyxin-resistant bacterial populations following polymyxin treatment. Antibiotic combination therapies seem the most promising option for minimizing the emergence of polymyxin resistance.

scholarly journals Pharmacokinetics and Pharmacodynamics of Minocycline against Acinetobacter baumannii in a Neutropenic Murine Pneumonia Model

2017 ◽  
Vol 61 (5) ◽  
Author(s):  
Jian Zhou ◽  
Kimberly R. Ledesma ◽  
Kai-Tai Chang ◽  
Henrietta Abodakpi ◽  
Song Gao ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Multidrug Resistant ◽  
Time Curve ◽  
Content Type ◽  
Concentration Time ◽  
Dose Linearity ◽  
Unit Reduction ◽  
The Relationship

ABSTRACT Multidrug-resistant (MDR) Acinetobacter baumannii is increasingly more prevalent in nosocomial infections. Although in vitro susceptibility of A. baumannii to minocycline is promising, the in vivo efficacy of minocycline has not been well established. In this study, the in vivo activity of minocycline was evaluated in a neutropenic murine pneumonia model. Specifically, we investigated the relationship between minocycline exposure and bactericidal activity using five A. baumannii isolates with a broad range of susceptibility (MIC ranged from 0.25 mg/liter to 16 mg/liter). The pharmacokinetics of minocycline (single dose of 25 mg/kg of body weight, 50 mg/kg, 100 mg/kg, and a humanized regimen, given intraperitoneally) in serum and epithelial lining fluid (ELF) were characterized. Dose linearity was observed for doses up to 50 mg/kg and pulmonary penetration ratios (area under the concentration-time curve in ELF from 0 to 24 h [AUCELF,0–24]/area under the concentration time curve in serum from 0 to 24 h [AUCserum,0–24]) ranged from 2.5 to 2.8. Pharmacokinetic-pharmacodynamics (PK-PD) index values in ELF for various dose regimens against different A. baumannii isolates were calculated. The maximum efficacy at 24 h was approximately 1.5-log-unit reduction of pulmonary bacterial burdens from baseline. The AUC/MIC ratio was the PK-PD index most closely correlating to the bacterial burden (r 2 = 0.81). The required AUCELF,0–24/MIC for maintaining stasis and achieving 1-log-unit reduction were 140 and 410, respectively. These findings could guide the treatment of infections caused by A. baumannii using minocycline in the future. Additional studies to examine resistance development during therapy are warranted.

scholarly journals Preferential Emergence of Reduced Vancomycin Susceptibility in Health Care-Associated Methicillin-Resistant Staphylococcus aureus Isolates during Continuous-Infusion Vancomycin Therapy in anIn VitroDynamic Model

2011 ◽  
Vol 55 (7) ◽  
pp. 3627-3630 ◽  
Author(s):  
Sheryl Zelenitsky ◽  
Noha Alkurdi ◽  
Zhanni Weber ◽  
Robert Ariano ◽  
George Zhanel
Keyword(s):  
Health Care ◽  
Staphylococcus Aureus ◽  
Continuous Infusion ◽  
Total Serum ◽  
Vancomycin Therapy ◽  
Time Curve ◽  
Bacterial Killing ◽  
Methicillin Resistant ◽  
Content Type ◽  
Concentration Time

ABSTRACTBacterial killing and the development of reduced vancomycin susceptibility during continuous-infusion vancomycin (CIV) therapy were dependent on the area under the concentration-time curve over 24 h divided by the MIC (ƒAUC24/MIC), with values of ≥240 (equivalent total serum AUC24/MICs of ≥480) being bactericidal and suppressing emerging resistance in methicillin-resistantStaphylococcus aureus(MRSA). Also, vancomycin therapy was less likely to be bactericidal and 4.4 times more likely to lead to reduced vancomycin susceptibility in health care-associated MRSA than in community-associated MRSA.

scholarly journals Evaluation of Meropenem Regimens Suppressing Emergence of Resistance in Acinetobacter baumannii with Human Simulated Exposure in anIn VitroIntravenous-Infusion Hollow-Fiber Infection Model

2014 ◽  
Vol 58 (11) ◽  
pp. 6773-6781 ◽  
Author(s):  
Xin Li ◽  
Lin Wang ◽  
Xian-Jia Zhang ◽  
Yang Yang ◽  
Wei-Tao Gong ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Hollow Fiber ◽  
Dosage Interval ◽  
Infection Model ◽  
Bacterial Killing ◽  
Content Type ◽  
Dosage Regimens ◽  
Drug Concentrations ◽  
Emergence Of Resistance

ABSTRACTThe emergence of resistance to carbapenems inPseudomonas aeruginosacan be suppressed by optimizing the administration of meropenem. However, whether the same is true forAcinetobacter baumanniiis not fully understood. We assessed the bactericidal activity of meropenem and its potency to suppress the emergence of resistance inA. baumanniiwith human simulated exposure in anin vitrointravenous-infusion hollow-fiber infection model (HFIM). Two clinical strains of carbapenem-susceptible multidrug-resistantA. baumannii(CS-MDRAB), CSRA24 and CSRA91, were used, and their MICs and mutant prevention concentrations (MPCs) were determined. Six meropenem dosage regimens (0.5, 1.0, or 2.0 g given every 8 h [q8h] with a 0.5-h or 3-h infusion for seven consecutive days) were simulated and then evaluated in the HFIM. Both the total population and resistant subpopulations of the two strains were quantified. Drug concentrations were measured by high-performance liquid chromatography. All dosage regimens, except for the lowest dosage (0.5 g for both the 0.5-h and 3-h infusions), showed 3-log CFU/ml bacterial killing. Dosage regimens of 2.0 g with 0.5-h and 3-h infusions exhibited an obvious bactericidal effect and suppressed resistance. Selective amplification of subpopulations with reduced susceptibility to meropenem was suppressed with a percentage of the dosage interval in which meropenem concentrations exceeded the MPC (T>MPC) of ≥20% or with a ratio ofT>MPC to the percentage of the dosage interval in which drug concentrations are within the mutant selection window of ≥0.25. Ourin vitrodata support the use of a high dosage of meropenem (2.0 g q8h) for the treatment of severe infection caused by CS-MDRAB.

scholarly journals Pharmacodynamics of Meropenem against Acinetobacter baumannii in a Neutropenic Mouse Thigh Infection Model

2020 ◽  
Vol 64 (4) ◽  
Author(s):  
Mojgan Sabet ◽  
Ziad Tarazi ◽  
David C. Griffith
Keyword(s):  
Acinetobacter Baumannii ◽  
Treatment Options ◽  
Free Drug ◽  
Clinical Isolates ◽  
Infection Model ◽  
First Line ◽  
Bacteriostatic Effect ◽  
Bacterial Killing ◽  
Content Type

ABSTRACT Acinetobacter baumannii infections are difficult to treat and have limited treatment options. Carbapenems, including meropenem, are currently considered the first-line agents for the treatment of infections caused by Acinetobacter spp. The percentage of a 24-hour period that the concentration of free drug in plasma is above the MIC (%24-h fT>MIC) to achieve stasis, 1 log CFU, or 2 log CFU of bacterial killing against A. baumannii has not been studied previously for meropenem. The objective of this study was to determine these parameters for meropenem against A. baumannii in a neutropenic mouse thigh infection model. Six A. baumannii clinical isolates with MICs ranging from 0.25 to 16 mg/liter were tested. Meropenem produced a bacteriostatic effect with a %24-h fT>MIC of 7 to 24% and produced 1 log CFU of bacterial killing with a %24-h fT>MIC of 15 to 37%.

NCSS notable trade book lesson plan: the girl who buried her dreams in a can

2020 ◽  
Vol 15 (2) ◽  
pp. 121-126
Author(s):  
Takisha Durm
Keyword(s):  
United States ◽  
Research Design ◽  
Design Methodology ◽  
Lesson Plan ◽  
The United States ◽  
Elementary Grades ◽  
Effect Change ◽  
Content Type ◽  
Similarities And Differences ◽  
Future Date

PurposeThe Girl Who Buried Her Dreams in a Can, written by Dr Tererai, profiles a cultural, yet global experience of the power of believing in one's dream. Through this study of the similarities and differences of how children in the United States and abroad live and dream of a better life, this lesson seeks to enhance students' understandings of the power and authority they possess to effect change not only within their own lives but also in the lives of countless others in world. After reading the text, students will work to create vision boards illustrating their plans to effect change within their homes, schools, communities, states or countries. They will present their plans to their peers. To culminate the lesson, the students will bury their dreams in can and collectively decide on a future date to revisit the can to determine how far they have progressed in accomplishing their goals.Design/methodology/approachThis is an elementary grades 3–6 lesson plan. There was no research design/methodology/approach included.FindingsAs this is a lesson plan and no actual research was represented, there are no findings.Originality/valueThis is an original lesson plan completed by the first author Takisha Durm.

scholarly journals Pharmacodynamics of Daptomycin against Enterococcus faecium and Enterococcus faecalis in the Murine Thigh Infection Model

2018 ◽  
Vol 62 (10) ◽  
Author(s):  
James M. Kidd ◽  
Kamilia Abdelraouf ◽  
Tomefa E. Asempa ◽  
Romney M. Humphries ◽  
David P. Nicolau
Keyword(s):  
Enterococcus Faecalis ◽  
Enterococcus Faecium ◽  
Hill Equation ◽  
Infection Model ◽  
Free Drug Concentration ◽  
Time Curve ◽  
Content Type ◽  
Concentration Time ◽  
The Hill ◽  
Susceptibility Breakpoint

ABSTRACT The Clinical and Laboratory Standards Institute (CLSI) daptomycin MIC susceptibility breakpoint for the treatment of enterococcal infections is ≤4 μg/ml. However, patients receiving daptomycin for the treatment of infections caused by enterococci with MICs of ≤4 μg/ml may experience treatment failures. We assessed the pharmacodynamics of daptomycin against enterococci in a neutropenic murine thigh infection model and determined the exposures necessary for bacteriostasis and a 1-log10-CFU reduction of Enterococcus faecalis and Enterococcus faecium. We further characterized daptomycin efficacy at clinically achievable exposures. Six E. faecium and 6 E. faecalis isolates (daptomycin MICs, 0.5 to 32 μg/ml) were studied. Daptomycin was administered at various doses over 24 h to achieve area under the free drug concentration-time curve-to-MIC ratios (fAUC0–24/MIC) ranging from 1 to 148. Daptomycin regimens that simulate mean human exposures following doses of 6, 8, and 10 mg/kg of body weight/day were also studied. Efficacy was assessed by the differences in the number of log10 CFU per thigh at 24 h. The Hill equation was used to estimate the fAUC0–24/MIC required to achieve bacteriostasis and a 1-log10-CFU reduction. For E. faecium, a 1-log10-CFU reduction required an fAUC0–24/MIC of 12.9 (R2 = 0.71). For E. faecalis, a 1-log10-CFU reduction was not achieved, while the fAUC0–24/MIC required for stasis was 7.2 (R2 = 0.8). With a human-simulated regimen of 6 mg/kg/day, a 1-log10-CFU reduction was observed in 3/3 E. faecium isolates with MICs of <4 μg/ml and 0/3 E. faecium isolates with MICs of ≥4 μg/ml; however, a 1-log10-CFU reduction was not achieved for any of the 6 E. faecalis isolates. These results, alongside clinical data, prompt a reevaluation of the current breakpoint.

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