scholarly journals In Vitro Activity and In Vivo Efficacy of Clavulanic Acid against Acinetobacter baumannii

2009 ◽  
Vol 53 (10) ◽  
pp. 4298-4304 ◽  
Author(s):  
Alejandro Beceiro ◽  
Rafael López-Rojas ◽  
Juan Domínguez-Herrera ◽  
Fernando Docobo-Pérez ◽  
Germán Bou ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Clavulanic Acid ◽  
Control Group ◽  
In Vitro Activity ◽  
Untreated Control Group ◽  
Time Kill ◽  
First Time ◽  
Bacterial Concentrations

ABSTRACT Clavulanic acid (CLA) exhibits low MICs against some Acinetobacter baumannii strains. The present study evaluates the efficacy of CLA in a murine model of A. baumannii pneumonia. For this purpose, two clinical strains, Ab11 and Ab51, were used; CLA MICs for these strains were 2 and 4 mg/liter, respectively, and the imipenem (IPM) MIC was 0.5 mg/liter for both. A pneumonia model in C57BL/6 mice was used. The CLA dosage (13 mg/kg of body weight given intraperitoneally) was chosen to reach a maximum concentration of the drug in serum similar to that in humans and a time during which the serum CLA concentration remained above the MIC equivalent to 40% of the interval between doses. Six groups (n = 15) were inoculated with Ab11 or Ab51 and were allocated to IPM or CLA therapy or to the untreated control group. In time-kill experiments, CLA was bactericidal only against Ab11 whereas IPM was bactericidal against both strains. CLA and IPM both decreased bacterial concentrations in lungs, 1.78 and 2.47 log10 CFU/g (P ≤ 0.001), respectively, in the experiments with Ab11 and 2.42 and 2.28 log10 CFU/g (P ≤ 0.001), respectively, with Ab51. IPM significantly increased the sterility of blood cultures over that for the controls with both strains (P ≤ 0.005); CLA had the same effect with Ab51 (P < 0.005) but not with Ab11 (P = 0.07). For the first time, we suggest that CLA may be used for the treatment of experimental severe A. baumannii infections.

scholarly journals Efficacy of Rifampin and Its Combinations with Imipenem, Sulbactam, and Colistin in Experimental Models of Infection Caused by Imipenem-Resistant Acinetobacter baumannii

2010 ◽  
Vol 54 (3) ◽  
pp. 1165-1172 ◽  
Author(s):  
María E. Pachón-Ibáñez ◽  
Fernando Docobo-Pérez ◽  
Rafael López-Rojas ◽  
Juan Domínguez-Herrera ◽  
Manuel E. Jiménez-Mejias ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Combined Treatment ◽  
Multidrug Resistant ◽  
Experimental Models ◽  
Blood Cultures ◽  
Control Group ◽  
Group I ◽  
Time Kill ◽  
Bacterial Concentrations

ABSTRACT There are currently no defined optimal therapies available for multidrug-resistant (MDR) Acinetobacter baumannii infections. We evaluated the efficacy of rifampin, imipenem, sulbactam, colistin, and their combinations against MDR A. baumannii in experimental pneumonia and meningitis models. The bactericidal in vitro activities of rifampin, imipenem, sulbactam, colistin, and their combinations were tested using time-kill curves. Murine pneumonia and rabbit meningitis models were evaluated using the A. baummnnii strain Ab1327 (with MICs for rifampin, imipenem, sulbactam, and colistin of 4, 32, 32, and 0.5 mg/liter, respectively). Mice were treated with the four antimicrobials and their combinations. For the meningitis model, the efficacies of colistin, rifampin and its combinations with imipenem, sulbactam, or colistin, and of imipenem plus sulbactam were assayed. In the pneumonia model, compared to the control group, (i) rifampin alone, (ii) rifampin along with imipenem, sulbactam, or colistin, (iii) colistin, or (iv) imipenem plus sulbactam significantly reduced lung bacterial concentrations (10.6 ± 0.27 [controls] versus 3.05 ± 1.91, 2.07 ± 1.82, 2.41 ± 1.37, 3.4 ± 3.07, 6.82 ± 3.4, and 4.22 ± 2.72 log10 CFU/g, respectively [means ± standard deviations]), increased sterile blood cultures (0% versus 78.6%, 100%, 93.3%, 93.8%, 73.3%, and 50%), and improved survival (0% versus 71.4%, 60%, 46.7%, 43.8%, 40%, and 85.7%). In the meningitis model rifampin alone or rifampin plus colistin reduced cerebrospinal fluid bacterial counts (−2.6 and −4.4 log10 CFU/ml). Rifampin in monotherapy or with imipenem, sulbactam, or colistin showed efficacy against MDR A. baumannii in experimental models of pneumonia and meningitis. Imipenem or sulbactam may be appropriate for combined treatment when using rifampin.

scholarly journals In Vitro and In Vivo Activity of AS101 against Carbapenem-Resistant Acinetobacter baumannii

2021 ◽  
Vol 14 (8) ◽  
pp. 823
Author(s):  
Tsung-Ying Yang ◽  
Sung-Pin Tseng ◽  
Heather Nokulunga Dlamini ◽  
Po-Liang Lu ◽  
Lin Lin ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Antibacterial Activities ◽  
Treated Group ◽  
Infection Model ◽  
High Dose ◽  
Mouse Infection Model ◽  
Carbapenem Resistant ◽  
Time Kill

The increasing trend of carbapenem-resistant Acinetobacter baumannii (CRAB) worldwide has become a concern, limiting therapeutic alternatives and increasing morbidity and mortality rates. The immunomodulation agent ammonium trichloro (dioxoethylene-O,O′-) tellurate (AS101) was repurposed as an antimicrobial agent against CRAB. Between 2016 and 2018, 27 CRAB clinical isolates were collected in Taiwan. The in vitro antibacterial activities of AS101 were evaluated using broth microdilution, time-kill assay, reactive oxygen species (ROS) detection and electron microscopy. In vivo effectiveness was assessed using a sepsis mouse infection model. The MIC range of AS101 for 27 CRAB isolates was from 0.5 to 32 µg/mL, which is below its 50% cytotoxicity (approximately 150 µg/mL). Bactericidal activity was confirmed using a time-kill assay. The antibacterial mechanism of AS101 was the accumulation of the ROS and the disruption of the cell membrane, which, in turn, results in cell death. The carbapenemase-producing A. baumannii mouse sepsis model showed that AS101 was a better therapeutic effect than colistin. The mice survival rate after 120 h was 33% (4/12) in the colistin-treated group and 58% (7/12) in the high-dose AS101 (3.33 mg/kg/day) group. Furthermore, high-dose AS101 significantly decreased bacterial population in the liver, kidney and spleen (all p < 0.001). These findings support the concept that AS101 is an ideal candidate for further testing in future studies.

scholarly journals Potency of omadacycline against Mycobacteroides abscessus clinical isolates in vitro and in a mouse model of pulmonary infection

2021 ◽  
Author(s):  
Danielle A. Nicklas ◽  
Emily C. Maggioncalda ◽  
Elizabeth Story-Roller ◽  
Benjamin Eichelman ◽  
Chavis Tabor ◽  
...  
Keyword(s):  
Mouse Model ◽  
Opportunistic Pathogen ◽  
Current Treatment ◽  
Clinical Isolates ◽  
Control Group ◽  
Chronic Infections ◽  
Human Dose ◽  
Time Kill

The incidence of nontuberculous mycobacterial diseases in the US is rising and has surpassed tuberculosis. Most notable among the nontuberculous mycobacteria is Mycobacteroides abscessus , an emerging environmental opportunistic pathogen capable of causing chronic infections. M. abscessus disease is difficult to treat and the current treatment recommendations include repurposed antibiotics, several of which are associated with undesirable side effects. In this study, we have evaluated the activity of omadacycline, a new tetracycline derivative, against M. abscessus using in vitro and in vivo approaches. Omadacycline exhibited an MIC 90 of 0.5 μg/ml against a panel of 32 contemporary M. abscessus clinical isolates several of which were resistant to antibiotics that are commonly used for treatment of M. abscessus disease. Omadacycline when combined with clarithromycin, azithromycin, cefdinir, rifabutin or linezolid also exhibited synergism against several M. abscessus strains and did not exhibit antagonism when combined with an additional nine antibiotics also commonly considered to treat M. abscessus disease. Concentration-dependent activity of omadacycline was observed in time-kill assessments. Efficacy of omadacycline was evaluated in a mouse model of lung infection against four M. abscessus strains. A dose equivalent to the 300 mg standard oral human dose was used. Compared to the untreated control group, within four weeks of treatment, 1 to 3 log 10 fewer M. abscessus colony forming units were observed in the lungs of mice treated with omadacycline. Treatment outcome was biphasic, with bactericidal activity observed after the first two weeks of treatment against all four M. abscessus strains.

scholarly journals In Vitro Activities of Colistin and Sitafloxacin Combinations against Multidrug-, Carbapenem-, and Colistin-Resistant Acinetobacter baumannii Using the Broth Microdilution Checkerboard and Time-Kill Methods

Antibiotics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 516
Author(s):  
Vipavee Rodjun ◽  
Jantana Houngsaitong ◽  
Preecha Montakantikul ◽  
Taniya Paiboonvong ◽  
Piyatip Khuntayaporn ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Clinical Studies ◽  
Tertiary Care ◽  
Resistant Isolate ◽  
Drug Resistant ◽  
Broth Microdilution ◽  
Time Kill ◽  
Tertiary Care Hospitals

Drug-resistant Acinetobacter baumannii (A. baumannii) infections are a critical global problem, with limited treatment choices. This study aims to determine the in vitro activities of colistin–sitafloxacin combinations against multidrug-, carbapenem- and colistin-resistant A. baumannii (MDR-AB, CRAB, CoR-AB, respectively) clinical isolates from tertiary care hospitals. We used the broth microdilution checkerboard and time-kill methods in this study. Synergy was found using both methods. The colistin–sitafloxacin combination showed synergy in MDR-AB, CRAB, and CoR-AB isolates (3.4%, 3.1%, and 20.9%, respectively). No antagonism was found in any type of drug-resistant isolate. The majority of CoR-AB isolates became susceptible to colistin (95.4%). The time-kill method also showed that this combination could suppress regrowth back to the initial inocula of all representative isolates. Our results demonstrated that the colistin–sitafloxacin combination might be an interesting option for the treatment of drug-resistant A. baumannii. However, further in vivo and clinical studies are required.

scholarly journals Doxorubicin-induced myocardial failure in rats with malignant neoplasm: Protective role of fullerenol C60(OH)24

2008 ◽  
Vol 62 (3) ◽  
pp. 197-204 ◽  
Author(s):  
Rade Injac ◽  
Aleksandar Djordjevic ◽  
Borut Strukelj
Keyword(s):  
Untreated Control ◽  
Malignant Neoplasm ◽  
In Vivo Studies ◽  
Control Group ◽  
High Dose ◽  
Sprague Dawley ◽  
Untreated Control Group ◽  
Cardiac Damage

The therapeutic utility of the anthracycline antibiotic doxorubicin is limited due to its cardiotoxicity. Our aim was to investigate the efficacy of fullerenol C60(OH)24 in preventing single, high-dose doxorubicin-induced cardiotoxicity in rats with malignant neoplasm. In vitro and in vivo studies have shown that fullerenol C60(OH)24, has strong antioxidative potential. Experiment was performed on adult female Sprague Dawley rats with chemically induced mammary carcinomas. All 32 rats (2-5 groups) received i.p. applications of 1-methyl-l-nitrosourea (MNU; 50 mg/kg body weight) on the 50th and 113th day of age. Animals were randomly divided into five groups as follows: (1) Untreated control group - rats received saline only; (2) Cancer control group - rats received MNU and saline; (3) Dox group - rats received MNU and Dox 8 mg/kg; (4) Full/Dox group -rats received MNU and Full 100 mg/kg 30 min before Dox 8 mg/kg; (5) Full group - rats received MNU and Full 100 mg/kg. Tumor incidence was 4.94 +- 0.576 per rat. The animals were sacrificed 2 days after the application of doxorubicin and/or fullerenol, and the serum activities of CK, LDH and ?-HBDH, as well as the levels of MDA, GSH, GSSG, GSH-Px, SOD, CAT, GR and TAS in the heart, were determined. The results obtained from the enzymatic activity in the serum show that the administration of a single dose of 8 mg/kg in all treated groups induces statistically significant damage. There are significant changes in the enzymes of LDH and CK (p < 0.05), after an i.p. administration of doxorubicin/fullerenol and fullerenol. Comparing all groups with untreated control group, point to the conclusion that in the case of a lower oc-HBDH/LDH ratio, results in more serious the liver parenchymal damage. The results revealed that doxorubicin induced oxidative damage and that the fullerenol antioxidative influence caused significant changes in MDA, GSH, GSSG, GSH-Px, SOD, CAT, GR and TAS level in the heart (p < 0.05). Ultra structural analysis of heart tissues from rats treated with doxorubicin and indicated that the hearts of the rats were protected from doxorubicin-induced subcellular damage. Doxorubicin/fullerenol rats did not appear to show significant cardiac damage although occasional focal loss of cristae in the mitochondria was observed. Therefore, it is suggested that fullerenol might be a potential cardioprotector in doxorubicin-treated individuals.

Promising in vitro Anti-Toxoplasma gondii effects of commercial Chitosan

2020 ◽  
Vol 20 ◽  
Author(s):  
Bahman Rahimi Esboei ◽  
Masoud Keighobadi ◽  
Hajar Ziaei Hezarjaribi ◽  
Mahdi Fakhar ◽  
Ahmad Daryani ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Control Group ◽  
Low Molecular Weight ◽  
In Vitro Activity ◽  
Obligate Intracellular ◽  
In Vivo Experiments ◽  
Ic50 Values ◽  
Acute Toxoplasmosis

Background: Toxoplasmosis is a disease that results from infection with an obligate intracellular T. gondii parasite, one of the world's most common parasites. Considering the complications of chemical drugs and the need for an appropriate drug combination for treatment of toxoplasmosis and also considering the antimicrobial potential of chitosan, as a natural source, this study was aimed to evaluate in vitro activity of commercial chitosan (CC) on T. gondii. Methods: In this experimental study, the tachyzoites of T. gondii was collected from the peritoneal exudates from infected Balb/c mice. The tachyzoites were diluted in phosphate buffer saline (PBS). Chitosan with low molecular weight was commercially purchased. Then, at concentrations of 10, 50, 100 and 200 µg/mL and after 30, 60, 120 and 180 minutes the viability of tachyzoites were determined by using trypan blue 0.1%. Anti-T.gondii activity of CC in all concentration was significantly higher than pyrimethamine as control group (P=0.05). Results: The concentration of 200 µg/mL of CC had the highest effects and killed 30.5, 52, 59 and 81.5% of tachyzoites after 30, 60, 120 and 180 minutes. Moreover, IC50 values of CC were 515, 171, 12.5 and <10 μg/mL in comparison with pyrimethamine as 58.82 μg/mL for 30, 60, 120, and 180 min of exposure time. Conclusion: Our results indicate chitosan in low molecular weight had potent activity against T. gondii tachyzoites and could be an appropriate candidate for treatment of at least acute toxoplasmosis, certainly, after complementary in vivo experiments.

scholarly journals In VitroandIn VivoActivities of E-101 Solution against Acinetobacter baumannii Isolates from U.S. Military Personnel

2011 ◽  
Vol 55 (7) ◽  
pp. 3603-3608 ◽  
Author(s):  
G. A. Denys ◽  
J. C. Davis ◽  
P. D. O'Hanley ◽  
J. T. Stephens
Keyword(s):  
Acinetobacter Baumannii ◽  
Bactericidal Activity ◽  
Military Personnel ◽  
Multidrug Resistant ◽  
Full Thickness ◽  
Content Type ◽  
Full Thickness Excision ◽  
Time Kill

ABSTRACTWe evaluated thein vitroandin vivoactivity of a novel topical myeloperoxidase-mediated antimicrobial, E-101 solution, against 5 multidrug-resistantAcinetobacter baumanniiisolates recovered from wounded American soldiers. Time-kill studies demonstrated rapid bactericidal activity against allA. baumanniistrains tested in the presence of 3% blood. Thein vitrobactericidal activity of E-101 solution againstA. baumanniistrains was confirmed in a full-thickness excision rat model. Additionalin vivostudies appear warranted.

scholarly journals In Vitro Activities of Various Antimicrobials Alone and in Combination with Tigecycline against Carbapenem-Intermediate or -Resistant Acinetobacter baumannii

2007 ◽  
Vol 51 (5) ◽  
pp. 1621-1626 ◽  
Author(s):  
Marc H. Scheetz ◽  
Chao Qi ◽  
John R. Warren ◽  
Michael J. Postelnick ◽  
Teresa Zembower ◽  
...  
Keyword(s):  
Acinetobacter Baumannii ◽  
Antimicrobial Susceptibility ◽  
Bloodstream Infections ◽  
Polymyxin B ◽  
In Vitro Susceptibility ◽  
Carbapenem Resistant ◽  
Susceptibility Profiles ◽  
Time Kill

ABSTRACT The activities of tigecycline alone and in combination with other antimicrobials are not well defined for carbapenem-intermediate or -resistant Acinetobacter baumannii (CIRA). Pharmacodynamic activity is even less well defined when clinically achievable serum concentrations are considered. Antimicrobial susceptibility testing of clinical CIRA isolates from 2001 to 2005 was performed by broth or agar dilution, as appropriate. Tigecycline concentrations were serially increased in time-kill studies with a representative of the most prevalent carbapenem-resistant clone (strain AA557; imipenem MIC, 64 mg/liter). The in vitro susceptibility of the strain was tested by time-kill studies in duplicate against the average free serum steady-state concentrations of tigecycline alone and in combination with various antimicrobials. Ninety-three CIRA isolates were tested and were found to have the following antimicrobial susceptibility profiles: tigecycline, MIC50 of 1 mg/liter and MIC90 of 2 mg/liter; minocycline, MIC50 of 0.5 mg/liter and MIC90 of 8 mg/liter; doxycycline, MIC50 of 2 mg/liter and MIC90 of ≥32 mg/liter; ampicillin-sulbactam, MIC50 of 48 mg/liter and MIC90 of 96 mg/liter; ciprofloxacin, MIC50 of ≥16 mg/liter and MIC90 of ≥16 mg/liter; rifampin, MIC50 of 4 mg/liter and MIC90 of 8 mg/liter; polymyxin B, MIC50 of 1 mg/liter and MIC90 of 1 mg/liter; amikacin, MIC50 of 32 mg/liter and MIC90 of ≥32 mg/liter; meropenem, MIC50 of 16 mg/liter and MIC90 of ≥128 mg/liter; and imipenem, MIC50 of 4 mg/liter and MIC90 of 64 mg/liter. Among the tetracyclines, the isolates were more susceptible to tigecycline than minocycline and doxycycline, according to FDA breakpoints (95%, 88%, and 71% of the isolates were susceptible to tigecycline, minocycline, and doxycycline, respectively). Concentration escalation studies with tigecycline revealed a maximal killing effect near the MIC, with no additional extent or rate of killing at concentrations 2× to 4× the MIC for tigecycline. Time-kill studies demonstrated indifference for tigecycline in combination with the antimicrobials tested. Polymyxin B, minocycline, and tigecycline are the most active antimicrobials in vitro against CIRA. Concentration escalation studies demonstrate that tigecycline may need to approach concentrations higher than those currently achieved in the bloodstream to adequately treat CIRA bloodstream infections. Future studies should evaluate these findings in vivo.

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