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The Journal of Antimicrobial... Nov 2022The current mutagenesis tools for Acinetobacter baumannii leave selection markers or residual sequences behind, or involve tedious counterselection and screening steps....
BACKGROUND
The current mutagenesis tools for Acinetobacter baumannii leave selection markers or residual sequences behind, or involve tedious counterselection and screening steps. Furthermore, they are usually adapted for model strains, rather than for MDR clinical isolates.
OBJECTIVES
To develop a scar-free genome-editing tool suitable for chromosomal and plasmid modifications in MDR A. baumannii AB5075.
METHODS
We prove the efficiency of our adapted genome-editing system by deleting the multidrug efflux pumps craA, cmlA5 and resistance island 2 (RI2), as well as curing plasmid p1AB5075, and combining these mutations. We then characterized the susceptibility of the mutants compared with the WT to different antibiotics (i.e. chloramphenicol, amikacin and tobramycin) by disc diffusion assays and determined the MIC for each strain.
RESULTS
We successfully adapted the genome-editing protocol to A. baumannii AB5075, achieving a double recombination frequency close to 100% and routinely securing the construction of a mutant within 10 working days. Furthermore, we show that both CraA and p1AB5075 are involved in chloramphenicol resistance, and that RI2 and p1AB5075 play a role in resistance to amikacin and tobramycin.
CONCLUSIONS
We have developed a versatile and highly efficient genome-editing tool for A. baumannii. We have demonstrated it can be used to modify both the chromosome and native plasmids. By challenging the method, we show the role of CraA and p1AB5075 in antibiotic resistance.
Topics: Acinetobacter baumannii; Amikacin; Anti-Bacterial Agents; Chloramphenicol; Tobramycin; Drug Resistance, Multiple, Bacterial; Microbial Sensitivity Tests
PubMed: 36216579
DOI: 10.1093/jac/dkac328 -
Antimicrobial Agents and Chemotherapy Jan 2017There has been a resurgence of interest in aerosolization of antibiotics for treatment of patients with severe pneumonia caused by multidrug-resistant pathogens. A...
Pharmacodynamics of Aerosolized Fosfomycin and Amikacin against Resistant Clinical Isolates of Pseudomonas aeruginosa and Klebsiella pneumoniae in a Hollow-Fiber Infection Model: Experimental Basis for Combination Therapy.
There has been a resurgence of interest in aerosolization of antibiotics for treatment of patients with severe pneumonia caused by multidrug-resistant pathogens. A combination formulation of amikacin-fosfomycin is currently undergoing clinical testing although the exposure-response relationships of these drugs have not been fully characterized. The aim of this study was to describe the individual and combined antibacterial effects of simulated epithelial lining fluid exposures of aerosolized amikacin and fosfomycin against resistant clinical isolates of Pseudomonas aeruginosa (MICs of 16 mg/liter and 64 mg/liter) and Klebsiella pneumoniae (MICs of 2 mg/liter and 64 mg/liter) using a dynamic hollow-fiber infection model over 7 days. Targeted peak concentrations of 300 mg/liter amikacin and/or 1,200 mg/liter fosfomycin as a 12-hourly dosing regimens were used. Quantitative cultures were performed to describe changes in concentrations of the total and resistant bacterial populations. The targeted starting inoculum was 10 CFU/ml for both strains. We observed that neither amikacin nor fosfomycin monotherapy was bactericidal against P. aeruginosa while both were associated with rapid amplification of resistant P. aeruginosa strains (about 10 to 10 CFU/ml within 24 to 48 h). For K. pneumoniae, amikacin but not fosfomycin was bactericidal. When both drugs were combined, a rapid killing was observed for P. aeruginosa and K. pneumoniae (6-log kill within 24 h). Furthermore, the combination of amikacin and fosfomycin effectively suppressed growth of resistant strains of P. aeruginosa and K. pneumoniae In conclusion, the combination of amikacin and fosfomycin was effective at maximizing bacterial killing and suppressing emergence of resistance against these clinical isolates.
Topics: Aerosols; Amikacin; Anti-Bacterial Agents; Colony Count, Microbial; Drug Administration Schedule; Drug Resistance, Multiple, Bacterial; Drug Synergism; Drug Therapy, Combination; Fosfomycin; Humans; Klebsiella pneumoniae; Microbial Sensitivity Tests; Models, Biological; Pseudomonas aeruginosa; Respiratory Mucosa
PubMed: 27795380
DOI: 10.1128/AAC.01763-16 -
The Journal of Antimicrobial... Nov 2022Mycobacterium abscessus (Mabs), a rapidly growing Mycobacterium species, is considered an MDR organism. Among the standard antimicrobial multi-drug regimens against...
BACKGROUND
Mycobacterium abscessus (Mabs), a rapidly growing Mycobacterium species, is considered an MDR organism. Among the standard antimicrobial multi-drug regimens against Mabs, amikacin is considered as one of the most effective. Parenteral amikacin, as a consequence of its inability to penetrate inside the cells, is only active against extracellular mycobacteria. The use of inhaled liposomal amikacin may yield improved intracellular efficacy by targeting Mabs inside the cells, while reducing its systemic toxicity.
OBJECTIVES
To evaluate the colocalization of an amikacin liposomal inhalation suspension (ALIS) with intracellular Mabs, and then to measure its intracellular anti-Mabs activity.
METHODS
We evaluated the colocalization of ALIS with Mabs in eukaryotic cells such as macrophages (THP-1 and J774.2) or pulmonary epithelial cells (BCi-NS1.1 and MucilAir), using a fluorescent ALIS and GFP-expressing Mabs, to test whether ALIS reaches intracellular Mabs. We then evaluated the intracellular anti-Mabs activity of ALIS inside macrophages using cfu and/or luminescence.
RESULTS
Using confocal microscopy, we demonstrated fluorescent ALIS and GFP-Mabs colocalization in macrophages and epithelial cells. We also showed that ALIS was active against intracellular Mabs at a concentration of 32 to 64 mg/L, at 3 and 5 days post-infection. Finally, ALIS intracellular activity was confirmed when tested against 53 clinical Mabs isolates, showing intracellular growth reduction for nearly 80% of the isolates.
CONCLUSIONS
Our experiments demonstrate the intracellular localization and intracellular contact between Mabs and ALIS, and antibacterial activity against intracellular Mabs, showing promise for its future use for Mabs pulmonary infections.
Topics: Humans; Amikacin; Mycobacterium abscessus; Eukaryotic Cells; Mycobacterium Infections, Nontuberculous; Anti-Bacterial Agents; Liposomes; Mycobacterium; Microbial Sensitivity Tests
PubMed: 36253948
DOI: 10.1093/jac/dkac348 -
Methods in Molecular Biology (Clifton,... 2016The components of the aminoglycosides, e.g., gentamicin, sisomicin, netilmicin, kanamycin, amikacin, and tobramycin, and related impurities of these antibiotics can be...
The components of the aminoglycosides, e.g., gentamicin, sisomicin, netilmicin, kanamycin, amikacin, and tobramycin, and related impurities of these antibiotics can be separated by means of micellar electrokinetic chromatography (MEKC). Derivatization with o-phthaldialdehyde and thioglycolic acid is found to be appropriate for these antibiotics. The background electrolyte was composed of sodium tetraborate (100 mM), sodium deoxycholate (20 mM), and β-cyclodextrin (15 mM) having a pH value of 10.0. This method is valid for evaluation of gentamicin, kanamycin, and tobramycin. It has to be adopted for amikacin, paromomycin, neomycin, and netilmicin.
Topics: Amikacin; Aminoglycosides; Anti-Bacterial Agents; Chromatography, Micellar Electrokinetic Capillary; Kanamycin; Micelles; Netilmicin; Sisomicin; Tobramycin; beta-Cyclodextrins
PubMed: 27645732
DOI: 10.1007/978-1-4939-6403-1_5 -
Scientific Reports Jun 2022Tuberculosis (TB) remains a leading infectious disease killer globally. Treatment outcomes are especially poor among people with extensively drug-resistant (XDR) TB,...
Tuberculosis (TB) remains a leading infectious disease killer globally. Treatment outcomes are especially poor among people with extensively drug-resistant (XDR) TB, until recently defined as rifampicin-resistant (RR) TB with resistance to an aminoglycoside (amikacin) and a fluoroquinolone (ofloxacin). We used laboratory TB test results from Western Cape province, South Africa between 2012 and 2015 to identify XDR-TB and pre-XDR-TB (RR-TB with resistance to one second-line drug) spatial hotspots. We mapped the percentage and count of individuals with RR-TB that had XDR-TB and pre-XDR-TB across the province and in Cape Town, as well as amikacin-resistant and ofloxacin-resistant TB. We found the percentage of pre-XDR-TB and the count of XDR-TB/pre-XDR-TB highly heterogeneous with geographic hotspots within RR-TB high burden areas, and found hotspots in both percentage and count of amikacin-resistant and ofloxacin-resistant TB. The spatial distribution of percentage ofloxacin-resistant TB hotspots was similar to XDR-TB hotspots, suggesting that fluoroquinolone-resistace is often the first step to additional resistance. Our work shows that interventions used to reduce XDR-TB incidence may need to be targeted within spatial locations of RR-TB, and further research is required to understand underlying drivers of XDR-TB transmission in these locations.
Topics: Amikacin; Antitubercular Agents; Extensively Drug-Resistant Tuberculosis; Fluoroquinolones; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Ofloxacin; South Africa; Tuberculosis, Multidrug-Resistant
PubMed: 35760977
DOI: 10.1038/s41598-022-14581-4 -
International Journal of Antimicrobial... Apr 2015The objective of this study was to assess the activity of amikacin in combination with doxycycline against clinical strains of Mycobacterium tuberculosis in the search...
The objective of this study was to assess the activity of amikacin in combination with doxycycline against clinical strains of Mycobacterium tuberculosis in the search for new strategies against multidrug-resistant (MDR) and extensively drug-resistant (XDR) tuberculosis. The study included 28 clinical M. tuberculosis strains, comprising 5 fully susceptible, 1 isoniazid-resistant, 17 MDR, 1 poly-resistant (streptomycin/isoniazid), 1 rifampicin-resistant and 3 XDR isolates, as well as the laboratory strain M. tuberculosis H37Rv. Minimum inhibitory concentrations (MICs) were determined using a modified chequerboard methodology in a BACTEC™ MGIT™ 960 System. Fractional inhibitory concentration indices (FICIs) were calculated, and synergy, indifference or antagonism was assessed. Whole-genome sequencing was performed to investigate the genetic basis of synergy, indifference or antagonism. The MIC50 and MIC90 values (MICs that inhibit 50% and 90% of the isolates, respectively) were, respectively, 0.5 mg/L and 1.0 mg/L for amikacin and 8 mg/L and 16 mg/L for doxycycline. The combination of amikacin and doxycycline showed a synergistic effect in 18 of the 29 strains tested and indifference in 11 strains. Antagonism was not observed. A streptomycin resistance mutation (K43R) was associated with indifference. In conclusion, the benefit of addition of doxycycline to an amikacin-containing regimen should be explored since in vitro results in this study indicate either synergy or indifference. Moreover, doxycycline also has immunomodulatory effects.
Topics: Amikacin; Antitubercular Agents; Doxycycline; Drug Resistance, Multiple, Bacterial; Drug Synergism; Humans; Microbial Sensitivity Tests; Mycobacterium tuberculosis; Pilot Projects; Tuberculosis, Multidrug-Resistant
PubMed: 25717028
DOI: 10.1016/j.ijantimicag.2014.11.017 -
The Senior Care Pharmacist Apr 2020To review the pharmacology, pharmacokinetics, pharmacodynamics, clinical efficacy, safety, administration, and role of amikacin liposome inhalation suspension (ALIS) in... (Review)
Review
To review the pharmacology, pharmacokinetics, pharmacodynamics, clinical efficacy, safety, administration, and role of amikacin liposome inhalation suspension (ALIS) in treatment of complex (MAC) lung disease.
A PubMed search using the terms "amikacin inhaled," "nebulized," and "liposome suspension" was performed. Selected infectious diseaseconference posters were also examined for relevant information. In addition, pertinent guidelines were reviewed.
Guidelines for the management of nontuberculous mycobacterial infections from the American Thoracic Society/ Infectious Diseases Society of America and the British Thoracic Society were used to summarize guidelinebased therapy (GBT). A phase II and a phase III clinical trial were reviewed to evaluate the role of ALIS in the treatment of MAC lung disease.
ALIS is a new formulation of inhaled amikacin (AMK) indicated for the treatment of MAC lung disease refractory to GBT in adults who are not candidates for intravenous AMK. An ongoing clinical trial has demonstrated that once-daily ALIS plus GBT results in higher rates of culture conversion compared with GBT alone by month 6 among patients with a mean age of 65 years. The most common adverse reactions associated with ALIS were dysphonia, cough, bronchospasm, hemoptysis, and ototoxicity. Nephrotoxicity was uncommon.
ALIS has been shown to increase culture conversion rates when added to GBT in adults with difficult-to-treat MAC lung disease. ALIS is associated with high rates of pulmonary and auditory adverse reactions and a low risk of renal adverse reactions. ALIS may be an attractive treatment option for older adults who are at high risk for nephrotoxicity.Topics: Amikacin; Anti-Bacterial Agents; Humans; Liposomes; Mycobacterium avium Complex; Mycobacterium avium-intracellulare Infection; United States
PubMed: 32192565
DOI: 10.4140/TCP.n.2020.162 -
Microbial Drug Resistance (Larchmont,... Jul 2022Colistin-based antibiotic therapies have been recommended for the treatment of multidrug-resistant infections. During colistin treatment, persister cells that tolerate...
Colistin-based antibiotic therapies have been recommended for the treatment of multidrug-resistant infections. During colistin treatment, persister cells that tolerate antibiotics may arise. Here we designed an study to assess the killing activity of colistin, meropenem, and amikacin on colistin-induced persisters in comparison with starvation-induced persisters. Colistin-induced persisters were generated under exposure to 10 × minimum inhibitory concentration dose of colistin, whereas starvation-induced persisters were produced by limitation of nutrients. In colistin-induced persisters, amikacin totally inhibited cell growth in 6 hours, whereas 98% of the cell population was inhibited by meropenem, and total eradication with meropenem was observed after 24 hours. Both antibiotics also inhibited metabolic activity >88%. The lack of killing effect under colistin exposure suggested to us that these cells could protect themselves from further colistin stress. There was no significant permeabilization change in the cellular membrane with all antibiotics. There was no killing effect on starvation-induced persister cells with the exposure to all antibiotics. In 6 hours, the metabolic activity of the persisters with meropenem and colistin increased 99% and 40%, respectively, whereas there was no increase with amikacin. The sustained inhibition with amikacin was an important finding for antipersister effect of amikacin. Amikacin had rapid and sustained antipersister activity on colistin-induced persister cells. During the colistin treatment of infection, the addition of amikacin to the regimen seems to be an effective approach to prevent a recurrence.
Topics: Amikacin; Anti-Bacterial Agents; Colistin; Klebsiella pneumoniae; Meropenem; Microbial Sensitivity Tests
PubMed: 35759379
DOI: 10.1089/mdr.2021.0207 -
Therapeutic Drug Monitoring Feb 2019Amikacin is widely used to treat severe Gram-negative bacterial infections. Its peak concentration in plasma is associated with treatment efficacy. Amikacin...
BACKGROUND
Amikacin is widely used to treat severe Gram-negative bacterial infections. Its peak concentration in plasma is associated with treatment efficacy. Amikacin pharmacokinetics (PK) is influenced by disease conditions, in addition to other patient characteristics. In this retrospective study, we evaluated the impact of clinical characteristics and disease condition on amikacin PK in children with burn injuries and those with cancer.
METHODS
Amikacin PK data from 66 children with burn injuries and 112 children with cancer were analyzed. A population PK model was developed using the nonlinear mixed-effects modeling approach. Models were developed using NONMEM 7.3 (ICON Development Solutions, LLC, Ellicott City, MD). Data processing and visualization was performed using R packages.
RESULTS
The amikacin PK data were best described by a 2-compartment model. The parameters were estimated with mean values (95% confidence intervals) as follows: central volume of distribution (V1), 5.70 L (4.64-6.76 L); central clearance, 2.12 L/h (1.79-2.46 L/h); peripheral volume of distribution (V2), 4.79 L (2.36-7.22 L); and distribution clearance (Q), 0.71 L/h (0.25-1.16 L/h). The final model identified the disease condition as a significant covariate and indicated 55% (28%-82%) higher central clearance and 17% (1%-34%) higher V1 in burn patients compared with cancer patients. Volume of distribution was significantly influenced by age and body weight. Clearance was significantly influenced by age, body weight, and creatinine clearance. Using the final PK model, we developed a workflow for selecting optimal dosing strategies for 3 representative pediatric patient profiles.
CONCLUSIONS
Disease condition was significant in influencing amikacin PK in children. To reach the same target concentrations (64 mg/L peak concentration) with a daily-dose plan, burn patients need higher doses than cancer patients. Future investigations are needed to explore the impact of other diseases on amikacin disposition in children, and to prospectively validate the proposed dosing strategy.
Topics: Adolescent; Amikacin; Anti-Bacterial Agents; Burns; Child; Child, Preschool; Female; Gram-Negative Bacterial Infections; Humans; Infant; Male; Neoplasms; Retrospective Studies
PubMed: 30299427
DOI: 10.1097/FTD.0000000000000568 -
Expert Opinion on Pharmacotherapy Jun 2020Non-tuberculous Mycobacteria (NTM) are a group of organisms whose importance in medicine seems to be increasing in recent times. The increasing number of patients... (Review)
Review
INTRODUCTION
Non-tuberculous Mycobacteria (NTM) are a group of organisms whose importance in medicine seems to be increasing in recent times. The increasing number of patients susceptible to these diseases make it necessary to expand our knowledge of therapeutic options and to explore future possibilities for the development of a therapeutic arsenal.
AREAS COVERED
In this review, the authors provide a brief introduction about the present importance of NTM and describe the present recommendations of the available guidelines for their treatment. They include a description of the future options for the management of these patients, especially focusing on new antibiotics. The authors also look at possibilities for future therapeutic options, such as antibiofilm strategies.
EXPERT OPINION
No actual changes have been made to the current recommendations for the management of most NTM infections (except perhaps the availability of nebulized amikacin). However, it is also true that we have increased the number of available antibiotic treatment options with good in vitro activity against NTM. The use of these drugs in selected cases could increase the therapeutic possibilities. However, some problems are still present, such as the knowledge of the actual meaning of a NTM isolate, and will probably be a key part of future research.
Topics: Amikacin; Anti-Bacterial Agents; Humans; Microbial Sensitivity Tests; Mycobacterium Infections, Nontuberculous; Nontuberculous Mycobacteria; Practice Guidelines as Topic
PubMed: 32200657
DOI: 10.1080/14656566.2020.1740205