scholarly journals In Vitro Antifungal Susceptibilities of Sporothrix schenckii in Two Growth Phases

2005 ◽  
Vol 49 (9) ◽  
pp. 3952-3954 ◽  
Author(s):  
Luciana Trilles ◽  
Belkys Fernández-Torres ◽  
Márcia dos Santos Lazéra ◽  
Bodo Wanke ◽  
Armando de Oliveira Schubach ◽  
...  
Keyword(s):  
Significant Influence ◽  
Growth Phase ◽  
Sporothrix Schenckii ◽  
Clinical Isolates ◽  
Growth Phases ◽  
Dimorphic Fungus ◽  
Microdilution Method

ABSTRACT We have determined the antifungal susceptibilities of 34 clinical isolates of the dimorphic fungus Sporothrix schenckii to 11 drugs using a microdilution method. In general, the type of growth phase (mycelial or yeast) and the temperature of incubation (30 or 35°C) exerted a significant influence on the MICs.

scholarly journals In Vitro Activities of the Novel Oxazolidinones DA-7867 and DA-7157 against Rapidly and Slowly Growing Mycobacteria

2006 ◽  
Vol 50 (12) ◽  
pp. 4027-4029 ◽  
Author(s):  
Lucio Vera-Cabrera ◽  
Barbara A. Brown-Elliott ◽  
Richard J. Wallace ◽  
Jorge Ocampo-Candiani ◽  
Oliverio Welsh ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Clinical Isolates ◽  
Nontuberculous Mycobacterium ◽  
The Novel ◽  
Broth Microdilution ◽  
Reference Species ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Aerobic Actinomycetes

ABSTRACT DA-7867 and DA-7157 are oxazolidinones active against pathogenic aerobic actinomycetes including Nocardia spp. and Mycobacterium tuberculosis. However, the activity of these drugs against nontuberculous mycobacterium (NTM) species is not known. In this work, we compared the susceptibilities of 122 clinical isolates and 29 reference species of both rapidly growing and slowly growing mycobacteria to linezolid, DA-7867, and DA-7157 by the broth microdilution method. The MICs for 50 and 90% of the strains tested (MIC50s and MIC90s, respectively) of DA-7867 and DA-7157 were lower than those of linezolid. In all of the cases, a MIC90 of <8 μg/ml was observed for all of the species tested in both groups of NTM. For M. kansasii and M. marinum isolates, the MIC90s of both DA-7867 and DA-7157 were less than 0.5 μg/ml. These results demonstrate the potential of these compounds to treat NTM infections.

scholarly journals Rapid in vitro selection of salt-tolerant genotypes of the potentially medicinal plant Centaurium maritimum (L.) fritsch

2009 ◽  
Vol 61 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Danijela Misic ◽  
B. Siler ◽  
Biljana Filipovic ◽  
Zorica Popovic ◽  
Suzana Zivkovic ◽  
...  
Keyword(s):  
Seed Germination ◽  
Medicinal Plant ◽  
Salinity Tolerance ◽  
Growth Phase ◽  
In Vitro Selection ◽  
Growth Phases ◽  
Salt Tolerant ◽  
Variable Response ◽  
Selection Of

We investigated differences of salinity tolerance between 'salt-tolerant' (ST) and 'salt-sensitive' (SS) genotypes of yellow centaury [Centaurium maritimum (L.) Fritsch] selected during the germination phase. The ability of in vitro cultured C. maritimum to complete the whole ontogenetic cycle in less than 6 months enabled us to deterine salinity tolerance during different growth phases. Based on the physiological attributes measured in this study (growth, morphogenesis, photosynthesis, flowering, seed germination), it can be concluded that C. maritimum genotypes differing in salinity tolerance showed a variable response to elevated salt concentrations during both the vegetative and the generative growth phase.

scholarly journals In Vitro Activity of Eravacycline against Gram-Positive Bacteria Isolated in Clinical Laboratories Worldwide from 2013 to 2017

2019 ◽  
Vol 64 (3) ◽  
Author(s):  
Ian Morrissey ◽  
Stephen Hawser ◽  
Sibylle H. Lob ◽  
James A. Karlowsky ◽  
Matteo Bassetti ◽  
...  
Keyword(s):  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Gram Positive ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Microdilution Method ◽  
Clinical Laboratories ◽  
Broth Microdilution Method ◽  
Doubling Dilution

ABSTRACT Eravacycline is a novel, fully synthetic fluorocycline antibiotic being developed for the treatment of serious infections, including those caused by resistant Gram-positive pathogens. Here, we evaluated the in vitro activities of eravacycline and comparator antimicrobial agents against a recent global collection of frequently encountered clinical isolates of Gram-positive bacteria. The CLSI broth microdilution method was used to determine in vitro MIC data for isolates of Enterococcus spp. (n = 2,807), Staphylococcus spp. (n = 4,331), and Streptococcus spp. (n = 3,373) isolated primarily from respiratory, intra-abdominal, urinary, and skin specimens by clinical laboratories in 37 countries on three continents from 2013 to 2017. Susceptibilities were interpreted using both CLSI and EUCAST breakpoints. There were no substantive differences (a >1-doubling-dilution increase or decrease) in eravacycline MIC90 values for different species/organism groups over time or by region. Eravacycline showed MIC50 and MIC90 results of 0.06 and 0.12 μg/ml, respectively, when tested against Staphylococcus aureus, regardless of methicillin susceptibility. The MIC90 values of eravacycline for Staphylococcus epidermidis and Staphylococcus haemolyticus were equal (0.5 μg/ml). The eravacycline MIC90s for Enterococcus faecalis and Enterococcus faecium were 0.06 μg/ml and were within 1 doubling dilution regardless of the vancomycin susceptibility profile. Eravacycline exhibited MIC90 results of ≤0.06 μg/ml when tested against Streptococcus pneumoniae and beta-hemolytic and viridans group streptococcal isolates. In this surveillance study, eravacycline demonstrated potent in vitro activity against frequently isolated clinical isolates of Gram-positive bacteria (Enterococcus, Staphylococcus, and Streptococcus spp.), including isolates collected over a 5-year period (2013 to 2017), underscoring its potential benefit in the treatment of infections caused by common Gram-positive pathogens.

scholarly journals 681. In vitro Activity of the β-Lactamase Inhibitor QPX7728 in Combination with Several β-Lactams Against Acinetobacter baumannii (AB) and Pseudomonas aeruginosa (PSA)

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S310-S311 ◽  
Author(s):  
Olga Lomovskaya ◽  
Jill Lindley ◽  
Debora Rubio-Aparicio ◽  
Kirk J Nelson ◽  
Mariana Castanheira
Keyword(s):  
Resistance Mechanisms ◽  
Vitro Activity ◽  
Clinical Isolates ◽  
In Vitro Activity ◽  
Microdilution Method ◽  
Carbapenem Resistant ◽  
Broth Microdilution Method ◽  
Data Representative ◽  
Lactamase Inhibitor

Abstract Background QPX7728 (QPX) is a novel broad-spectrum boron-containing inhibitor of serine- and metallo-β-lactamases (MBLs). We evaluated the in vitro activity of QPX combined with several β-lactams against carbapenem-resistant AB (CRAB) and PSA clinical isolates with varying β-lactam resistance mechanisms. Methods A total of 503 CRAB (meropenem [MEM] MIC ≥8 µg/mL) and 762 PSA clinical isolates were tested by the reference broth microdilution method against β-lactams alone and combined with QPX (4 µg/mL and 8 µg/mL). PSA isolates were selected to represent the normal distribution of MEM, ceftazidime–avibactam (CAZ-AVI), and ceftolozane-tazobactam (TOL-TAZ) resistance according to 2017 surveillance data (representative panel). Additionally, 262 PSA isolates that were either nonsusceptible (NS) to MEM (MIC, ≥4 µg/mL) or to TOL-TAZ (MIC, ≥8 µg/mL), or resistant (R) to CAZ-AVI (MIC, ≥16 µg/mL) (challenge panel) were also tested. Within this 262 strain challenge set, 56 strains carried MBLs and the majority also had nonfunctional OprD. Results Against CRAB, QPX at 4 and 8 µg/mL increased the potency of all β-lactams tested. MEM-QPX was the most potent combination (table) displaying MIC50/MIC90 at 1/8 and 0.5/4 µg/mL with QPX at fixed 4 and 8 µg/mL, respectively. Susceptibility (S) to MEM was restored in >95% of strains. Against the 500 PSA from the representative panel, S for all QPX combinations was >90%. For the challenge panel, TOL-QPX and piperacillin (PIP)-QPX were the most potent combinations, restoring S in 76–77% of strains. TOL-QPX and MEM-QPX or cefepime (FEP)-QPX restored the MIC values to S rates when applying the CLSI breakpoint for the compound alone (comparison purposes only) in ~90% and ~75% of non-MBL-producing strains, respectively, vs. 60–70% for TOL-TAZ and CAZ-AVI. PIP-QPX reduce the MIC values to S values for PIP-TAZ in ~60% of MBL-producing strains vs. 20–30% and 3–7% for other QPX combinations and non-QPX tested combinations, respectively. Conclusion Combinations of QPX with various β-lactam antibiotics displayed potent activity against CRAB and resistant PSA isolates and warrant further investigation. Disclosures All authors: No reported disclosures.

scholarly journals Antifungal activity of thymol against clinical isolates of fluconazole-sensitive and -resistant Candida albicans

2009 ◽  
Vol 58 (8) ◽  
pp. 1074-1079 ◽  
Author(s):  
Na Guo ◽  
Jingbo Liu ◽  
Xiuping Wu ◽  
Xingming Bi ◽  
Rizeng Meng ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Antifungal Activity ◽  
Concentration Index ◽  
Inhibitory Concentration ◽  
Clinical Isolates ◽  
Standard Strain ◽  
Antagonistic Action ◽  
Microdilution Method ◽  
Interaction Intensity

Thymol (THY) was found to have in vitro antifungal activity against 24 fluconazole (FLC)-resistant and 12 FLC-susceptible clinical isolates of Candida albicans, standard strain ATCC 10231 and one experimentally induced FLC-resistant C. albicans S-1. In addition, synergism was observed for clinical isolates of C. albicans with combinations of THY–FLC and THY–amphotericin B (AMB) evaluated by the chequerboard microdilution method. The interaction intensity was determined by spectrophotometry for the chequerboard assay, and the nature of the interactions was assessed using two non-parametric approaches [fractional inhibitory concentration index (FICI) and ΔE models]. The interaction between THY–FLC or THY–AMB in FLC-resistant and -susceptible strains of C. albicans showed a high percentage of synergism by the FICI method and the ΔE method. The ΔE model gave results consistent with FICI, and no antagonistic action was observed in the strains tested.

scholarly journals Results from the China Antimicrobial Surveillance Network (CHINET) in 2017 of the In Vitro Activities of Ceftazidime-Avibactam and Ceftolozane-Tazobactam against Clinical Isolates of Enterobacteriaceae and Pseudomonas aeruginosa

2019 ◽  
Vol 63 (4) ◽  
Author(s):  
Dandan Yin ◽  
Shi Wu ◽  
Yang Yang ◽  
Qingyu Shi ◽  
Dong Dong ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Clinical Isolates ◽  
Surveillance Network ◽  
Content Type ◽  
Highly Active ◽  
Microdilution Method ◽  
Carbapenem Resistant ◽  
Antimicrobial Surveillance ◽  
Broth Microdilution Method

ABSTRACT The in vitro activities of ceftazidime-avibactam (CZA), ceftolozane-tazobactam (C-T), and comparators were determined for 1,774 isolates of Enterobacteriaceae and 524 isolates of Pseudomonas aeruginosa collected by 30 medical centers from the China Antimicrobial Surveillance Network (CHINET) in 2017. Antimicrobial susceptibility testing was performed by the CLSI broth microdilution method, and blaKPC and blaNDM were detected by PCR for all carbapenem-resistant Enterobacteriaceae (CRE). Ceftazidime-avibactam demonstrated potent activity against almost all Enterobacteriaceae (94.6% susceptibility; MIC50, ≤0.25 mg/liter; MIC90, ≤0.25 to >32 mg/liter) and good activity against P. aeruginosa (86.5% susceptibility; MIC50/90, 2/16 mg/liter). Among the CRE, 50.8% (189/372 isolates) were positive for blaKPC-2, which mainly existed in ceftazidime-avibactam-susceptible Klebsiella pneumoniae isolates (92.1%, 174/189). Among the CRE, 17.7% (66/372 isolates) were positive for blaNDM, which mainly existed in strains resistant to ceftazidime-avibactam (71.7%, 66/92). Ceftolozane-tazobactam showed good in vitro activity against Escherichia coli and Proteus mirabilis (MIC50/90, ≤0.5/2 mg/liter; 90.5 and 93.8% susceptibility, respectively), and the rates of susceptibility of K. pneumoniae (MIC50/90, 2/>64 mg/liter) and P. aeruginosa (MIC50/90, 1/8 mg/liter) were 52.7% and 88.5%, respectively. Among the CRE strains, 28.6% of E. coli isolates and 85% of K. pneumoniae isolates were still susceptible to ceftazidime-avibactam, but only 7.1% and 1.9% of them, respectively, were susceptible to ceftolozane-tazobactam. The rates of susceptibility of the carbapenem-resistant P. aeruginosa isolates to ceftazidime-avibactam (65.7%) and ceftolozane-tazobactam (68%) were similar. Overall, both ceftazidime-avibactam and ceftolozane-tazobactam were highly active against clinical isolates of Enterobacteriaceae and P. aeruginosa recently collected across China, and ceftazidime-avibactam showed activity superior to that of ceftolozane-tazobactam against Enterobacteriaceae, whereas ceftolozane-tazobactam showed a better effect against P. aeruginosa.

scholarly journals In Vitro Activity of Meropenem-Vaborbactam against Clinical Isolates of KPC-Positive Enterobacteriaceae

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Meredith A. Hackel ◽  
Olga Lomovskaya ◽  
Michael N. Dudley ◽  
James A. Karlowsky ◽  
Daniel F. Sahm
Keyword(s):  
Clinical Isolates ◽  
In Vitro Activity ◽  
Broth Microdilution ◽  
Content Type ◽  
Class A ◽  
Microdilution Method ◽  
Fixed Concentration ◽  
Broth Microdilution Method ◽  
The U.S

ABSTRACT Vaborbactam (formerly RPX7009) is a novel inhibitor of serine β-lactamases, including Ambler class A carbapenemases, such as KPCs. The current study evaluated the in vitro activity of the combination agent meropenem-vaborbactam against a global collection of 991 isolates of KPC-positive Enterobacteriaceae collected in 2014 and 2015 using the Clinical and Laboratory Standards Institute (CLSI) standard broth microdilution method. The MIC90 of meropenem (when tested with a fixed concentration of 8 μg/ml of vaborbactam) for isolates of KPC-positive Enterobacteriaceae was 1 μg/ml, and MIC values ranged from ≤0.03 to >32 μg/ml; 99.0% (981/991) of isolates had meropenem-vaborbactam MICs of ≤4 μg/ml, the U.S. FDA-approved MIC breakpoint for susceptibility to meropenem-vaborbactam (Vabomere). Vaborbactam lowered the meropenem MIC50 from 32 to 0.06 μg/ml and the MIC90 from >32 to 1 μg/ml. There were no differences in the activity of meropenem-vaborbactam when the isolates were stratified by KPC variant type. We conclude that meropenem-vaborbactam demonstrates potent in vitro activity against a worldwide collection of clinical isolates of KPC-positive Enterobacteriaceae collected in 2014 and 2015.

scholarly journals In vitro activity of imipenem/relebactam against Gram-negative clinical isolates in two Spanish tertiary hospitals

2021 ◽  
Author(s):  
Marina Peñuelas ◽  
◽  
Cristina García-Salguero ◽  
Melania Iñigo ◽  
Jose Manuel Viñuela-Prieto ◽  
...  
Keyword(s):  
High Activity ◽  
Clinical Isolates ◽  
Beta Lactamase ◽  
Extended Spectrum Beta Lactamase ◽  
Klebsiella Pneumoniae Carbapenemase ◽  
Microdilution Method ◽  
Broth Microdilution Method ◽  
Class B ◽  
Tertiary Hospitals

Objetive. The aim of this study was to analyze the activity of the imipenem-relebactam combination (IMI/REL) against a collection of multidrug-resist Enterobacterales, Pseudomonas aeruginosa and Acinetobacter baumannii clinical isolates. Material and methods. The study was conducted in two tertiary hospitals in Spain and included 192 clinical isolates of these 3 genera (139 resistant and 53 susceptible to IMI). The MICs for IMI with and without REL (at a fixed concentration of 4 mg/L) were determined by a standard broth microdilution method according to international recommendations. Results. All IMI-susceptible E. coli strains were also susceptible to IMI/REL. Enterobacterales resistant to IMI due to the production of carbapenemases, the MIC50 and MIC90 decreased from 64/256 with IMI to 8/64 mg/L with IMI/REL. This high activity was principally detected among isolates with KPC enzymes. Enterobacterales with class B carbapenemases, P. aeruginosa carrying VIM carbapenemase and A. baumannii strains showed no changes on IMI MIC50 or MIC90 after adding REL. Among P. aeruginosa strains without carbapenemase the MIC for IMI/REL was reduced between 1 to 5 dilutions. Conclusions. IMI/REL showed high activity against the strains that carry Klebsiella pneumoniae carbapenemase (KPC) and against carbapenem-resistant P. aeruginosa unrelated to the VIM enzyme, mainly AmpC beta lactamase associated with impermeability. Against strains carrying oxacillinase 48 (OXA-48) associated with extended-spectrum beta-lactamase (ESBL), IMI/REL presented activity only slightly better than IMI and had no beneficial effect superior to IMI against A. baumannii.

scholarly journals Comparative resistance of Candida albicans clinical isolates to fluconazole and itraconazole in vitro and in vivo in a murine model.

1996 ◽  
Vol 40 (6) ◽  
pp. 1342-1345 ◽  
Author(s):  
A Valentin ◽  
R Le Guennec ◽  
E Rodriguez ◽  
J Reynes ◽  
M Mallie ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Murine Model ◽  
Survival Rates ◽  
Drug Regimen ◽  
Clinical Isolates ◽  
In Vitro Susceptibility ◽  
Microdilution Method ◽  
Broth Microdilution Method

Relationships between azole susceptibility and in vivo response to antifungal therapy in a murine model of candidiasis were investigated for Candida albicans isolates sampled from human immunodeficiency virus type 1-positive patients with oropharyngeal candidiasis. The susceptibilities of seven clinical isolates and two reference strains to fluconazole (FCZ) and itraconazole (ITZ) were determined in vitro by the broth microdilution method. Four isolates were resistant to FCZ and ITZ, two were susceptible to both azoles, and three were resistant to FCZ and susceptible to ITZ (dissociated resistance). CD1 mice were inoculated with each isolate and treated with either FCZ or ITZ (drug regimen, 5 mg/kg of body weight twice daily for 5 days). Quantitative cultures of kidneys were performed at the end of the treatment. On the other hand, the survival rates of the mice were followed daily. These two parameters were clearly correlated with in vitro susceptibility. Thus, the phenomenon of a dissociation of resistance to FCZ and ITZ may be found in vivo as well as in vitro.

Sign in / Sign up

Export Citation Format

Share Document