Faculty Opinions recommendation of In vitro survey of triazole cross-resistance among more than 700 clinical isolates of Aspergillus species.

2008 ◽  
Author(s):  
Ana Espinel-Ingroff
Keyword(s):  
Clinical Isolates ◽  
Aspergillus Species ◽  
Cross Resistance

scholarly journals In Vitro Survey of Triazole Cross-Resistance among More than 700 Clinical Isolates of Aspergillus Species

2008 ◽  
Vol 46 (8) ◽  
pp. 2568-2572 ◽  
Author(s):  
M. A. Pfaller ◽  
S. A. Messer ◽  
L. Boyken ◽  
C. Rice ◽  
S. Tendolkar ◽  
...  
Keyword(s):  
Clinical Isolates ◽  
Aspergillus Species ◽  
Cross Resistance

scholarly journals Activity of voriconazole (UK-109,496) against clinical isolates of Aspergillus species and its effectiveness in an experimental model of invasive pulmonary aspergillosis.

1997 ◽  
Vol 41 (3) ◽  
pp. 696-698 ◽  
Author(s):  
M Murphy ◽  
E M Bernard ◽  
T Ishimaru ◽  
D Armstrong
Keyword(s):  
Body Weight ◽  
Experimental Model ◽  
Antifungal Agent ◽  
Invasive Pulmonary Aspergillosis ◽  
Clinical Isolates ◽  
Aspergillus Species ◽  
Pulmonary Aspergillosis

Voriconazole, a new azole antifungal agent, showed potent activity against clinical isolates of Aspergillus spp. in vitro. For A. fumigatus, the MIC range was < 0.03 to 0.5 microgram/ml and the MIC at which 90% of isolates are inhibited was 0.25 microgram/ml. In an experimental model of invasive pulmonary aspergillosis which mimics infection in humans, oral voriconazole at dosages of 30 mg/kg of body weight per day significantly delayed or prevented mortality.

Susceptibility of Candida spp. clinical isolates to antimycotics and disinfectants

2010 ◽  
Vol 5 (6) ◽  
pp. 821-826
Author(s):  
Monika Staniszewska ◽  
Beata Rozbicka ◽  
Aleksandra Rajnisz ◽  
Ewa Bocian ◽  
Ewa Wasińska ◽  
...  
Keyword(s):  
Clinical Isolates ◽  
Cross Resistance ◽  
Biocidal Activity ◽  
Candida Spp ◽  
In Vitro Susceptibility ◽  
Minimal Inhibitory Concentrations ◽  
Antiseptic Agent ◽  
Resistant Strains ◽  
Candida Infections

AbstractThe incidence of candidiasis among immunocompromised patients and emergence of antimycotics resistant strains has increased significantly. The aims of this study were: to examine the in vitro activity of antimycotics and biocides against Candida clinical isolates; to detect cross-resistance of fungi to these preparations and to estimate whether disinfectants applied in hospital areas are active against clinical Candida isolates. In vitro susceptibility of 102 Candida isolates to eight antimycotics was examined by Etest and ATB Fungus. Sensitivity of these strains to four disinfectants and an antiseptic agent was tested according to EN 1275:2005. Amphotericin B, caspofungin and 5-fluorocytosine were the most effective antimycotics against all Candida isolates. Resistance to itraconazole and fluconazole was observed among C. krusei and C. glabrata. The MICs (Minimal Inhibitory Concentrations) for ketoconazole, voriconazole and posaconazole against Candida albicans ranged: 0.003 - >32 μg/ml and one strain was resistant to three agents tested. All analysed Candida strains were sensitive to biocides containing either chlorine, aldehyde, alcohol mixtures, glucoprotamin or chlorhexidine gluconate with isopropanol. Sensitivity to these agents was observed at concentrations lower than those concentrations recommended by manufacturers to achieve proper biocidal activity to those preparations. Our data suggest that these disinfectants can be effectively applied in clinical wards to prevent nosocomial Candida infections.

scholarly journals In VitroActivity of AZD5847 against Geographically Diverse Clinical Isolates of Mycobacterium tuberculosis

2014 ◽  
Vol 58 (7) ◽  
pp. 4222-4223 ◽  
Author(s):  
Jim Werngren ◽  
Maria Wijkander ◽  
Nasrin Perskvist ◽  
V. Balasubramanian ◽  
Vasan K. Sambandamurthy ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Lavage Fluid ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Cross Resistance ◽  
Drug Candidate ◽  
Content Type ◽  
Geographical Regions ◽  
Lung Biopsies

ABSTRACTThe MIC of the novel antituberculosis (anti-TB) drug AZD5847 was determined against 146 clinical isolates from diverse geographical regions, including eastern Europe, North America, Africa, and Asia, using the automated Bactec Mycobacterial Growth Indicator Tube (MGIT) 960 system. These isolates originated from specimen sources such as sputum, bronchial alveolar lavage fluid, pleural fluid, abscess material, lung biopsies, and feces. The overall MIC90was 1.0 mg/liter (range, 0.125 to 4 mg/liter). The MICs of AZD5847 for isolates ofMycobacterium tuberculosiswere similar among drug-sensitive strains, multidrug-resistant (MDR) strains, and extensively drug resistant (XDR) strains. The goodin vitroactivity of AZD5847 againstM. tuberculosisand the lack of cross-resistance make this agent a promising anti-TB drug candidate.

scholarly journals Genetic Analyses of Mutations Contributing to Fluoroquinolone Resistance in Clinical Isolates ofStreptococcus pneumoniae

2001 ◽  
Vol 45 (12) ◽  
pp. 3517-3523 ◽  
Author(s):  
L. M. Weigel ◽  
G. J. Anderson ◽  
R. R. Facklam ◽  
F. C. Tenover
Keyword(s):  
Amino Acid ◽  
Antimicrobial Agents ◽  
Clinical Isolates ◽  
Fluoroquinolone Resistance ◽  
Cross Resistance ◽  
Genetic Analyses ◽  
High Level ◽  
Susceptibility Profiles ◽  
Level Resistance

ABSTRACT Twenty-one clinical isolates of Streptococcus pneumoniae showing reduced susceptibility or resistance to fluoroquinolones were characterized by serotype, antimicrobial susceptibility, and genetic analyses of the quinolone resistance-determining regions (QRDRs) of gyrA,gyrB, parC, and parE. Five strains were resistant to three or more classes of antimicrobial agents. In susceptibility profiles for gatifloxacin, gemifloxacin, levofloxacin, moxifloxacin, ofloxacin, sparfloxacin, and trovafloxacin, 14 isolates had intermediate- or high-level resistance to all fluoroquinolones tested except gemifloxacin (no breakpoints assigned). Fluoroquinolone resistance was not associated with serotype or with resistance to other antimicrobial agents. Mutations in the QRDRs of these isolates were more heterogeneous than those previously reported for mutants selected in vitro. Eight isolates had amino acid changes at sites other than ParC/S79 and GyrA/S81; several strains contained mutations in gyrB, parE, or both loci. Contributions to fluoroquinolone resistance by individual amino acid changes, including GyrB/E474K, ParE/E474K, and ParC/A63T, were confirmed by genetic transformation of S. pneumoniae R6. Mutations in gyrB were important for resistance to gatifloxacin but not moxifloxacin, and mutation of gyrAwas associated with resistance to moxifloxacin but not gatifloxacin, suggesting differences in the drug-target interactions of the two 8-methoxyquinolones. The positions of amino acid changes within the four genes affected resistance more than did the total number of QRDR mutations. However, the effect of a specific mutation varied significantly depending on the agent tested. These data suggest that the heterogeneity of mutations will likely increase as pneumococci are exposed to novel fluoroquinolone structures, complicating the prediction of cross-resistance within this class of antimicrobial agents.

scholarly journals Flucytosine-Fluconazole Cross-Resistance in Purine-Cytosine Permease-Deficient Candida lusitaniae Clinical Isolates: Indirect Evidence of a Fluconazole Uptake Transporter

2003 ◽  
Vol 47 (4) ◽  
pp. 1275-1284 ◽  
Author(s):  
Thierry Noël ◽  
Fabienne François ◽  
Patrick Paumard ◽  
Christiane Chastin ◽  
Daniel Brèthes ◽  
...  
Keyword(s):  
In Vitro Selection ◽  
Single Gene ◽  
Resistance Mechanism ◽  
Cytosine Deaminase ◽  
Indirect Evidence ◽  
Clinical Isolates ◽  
Cross Resistance ◽  
Recessive Mutation ◽  
Candida Lusitaniae

ABSTRACT An unusual interaction between flucytosine and fluconazole was observed when a collection of 60 Candida lusitaniae clinical isolates was screened for cross-resistance. Among eight isolates resistant to flucytosine (MIC ≥ 128 μg/ml) and susceptible to fluconazole (0.5 < MIC < 2 μg/ml), four became flucytosine-fluconazole cross resistant when both antifungals were used simultaneously. Fluconazole resistance occurred only in the presence of high flucytosine concentrations, and the higher the fluconazole concentration used, the greater the flucytosine concentration necessary to trigger the cross-resistance. When the flucytosine- and fluconazole-resistant cells were grown in the presence of fluconazole alone, the cells reversed to fluconazole susceptibility. Genetic analyses of the progeny from crosses between resistant and sensitive isolates showed that resistance to flucytosine was derived from a recessive mutation in a single gene, whereas cross-resistance to fluconazole seemed to vary like a quantitative trait. We further demonstrated that the four clinical isolates were susceptible to 5-fluorouracil and that cytosine deaminase activity was unaffected. Kinetic transport studies with [14C]flucytosine showed that flucytosine resistance was due to a defect in the purine-cytosine permease. Our hypothesis was that extracellular flucytosine would subsequently behave as a competitive inhibitor of fluconazole uptake transport. Finally, in vitro selection of spontaneous and induced mutants indicated that such a cross-resistance mechanism could also affect other Candida species, including C. albicans, C. tropicalis, and C. glabrata. This is the first report of a putative fluconazole uptake transporter in Candida species and of a possible resistance mechanism associated with a deficiency in the uptake of this drug.

scholarly journals In Vitro Antimicrobial Activity of GSQ1530, a New Heteroaromatic Polycyclic Compound

2002 ◽  
Vol 46 (10) ◽  
pp. 3168-3174 ◽  
Author(s):  
Yigong Ge ◽  
Stacey Difuntorum ◽  
Sofia Touami ◽  
Ian Critchley ◽  
Roland Bürli ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Therapeutic Potential ◽  
Clinical Isolates ◽  
In Vivo Studies ◽  
Cross Resistance ◽  
Minimal Bactericidal Concentration ◽  
Gram Positive ◽  
In Vitro Antimicrobial Activity

ABSTRACT GSQ1530 is a compound derived from a newly identified class of antibiotics referred to as heteroaromatic polycyclic (HARP) antibiotics. The aim of this study was to assess the in vitro antimicrobial activity of GSQ1530. By using an NCCLS broth microdilution assay, the activities of GSQ1530 and other antibiotics were coevaluated against 215 clinical isolates. The MICs at which 90% of isolates are inhibited (MIC90s) of GSQ1530 for methicillin-susceptible Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) were 2 and 4 μg/ml, respectively. The MIC90s of GSQ1530 for the streptococci tested were 2 μg/ml or less, regardless of their susceptibilities to other antibiotics. The MIC90 of GSQ1530 for the enterococci tested (including vancomycin-resistant enterococci) was 4 μg/ml. No cross-resistance was found between GSQ1530 and other known antibiotics. In a separate assay, GSQ1530 demonstrated excellent activity against vancomycin-intermediate-susceptible staphylococci (MIC90, 1 μg/ml). The minimal bactericidal concentration test was conducted with 73 clinical isolates; GSQ1530 was cidal against streptococci and staphylococci but static against enterococci. An in vitro killing kinetic study revealed a time-dependent profile, with at least a 3-log reduction of bacterial growth within 6 h after exposure to four times the MICs of GSQ1530 for both S. aureus and Streptococcus pneumoniae. The checkerboard study showed that GSQ1530 had a synergistic interaction with rifampin against MRSA. The test medium was found to have little effect on in vitro antimicrobial potency. The MICs of GSQ1530 for gram-positive cocci were 4- to 32-fold higher in the presence of serum proteins. GSQ1530 has high levels of plasma protein binding (91 and 89% for rat and human plasma, respectively). These preliminary results demonstrate that GSQ1530, a representative compound of our novel HARP antibiotics, has broad-spectrum activity against gram-positive bacteria. This novel class of antibacterial compounds is profiled in vivo to assess the therapeutic potential in humans. Ongoing in vivo studies will assess whether this class of molecules has promising in vivo efficacy and safety profiles.

scholarly journals In Vitro Activity of Clofazimine against Nontuberculous Mycobacteria Isolated in Beijing, China

2018 ◽  
Vol 62 (7) ◽  
Author(s):  
Jingjing Luo ◽  
Xia Yu ◽  
Guanglu Jiang ◽  
Yuhong Fu ◽  
Fengmin Huo ◽  
...  
Keyword(s):  
Nontuberculous Mycobacteria ◽  
Clinical Isolates ◽  
Natural Resistance ◽  
Cross Resistance ◽  
Mycobacterium Fortuitum ◽  
Strong Activity ◽  
Content Type ◽  
Beijing China ◽  
Reference Strains

ABSTRACT Due to the natural resistance of nontuberculous mycobacteria (NTM) to many antibiotics, the treatment of diseases caused by NTM is often long-term but unsuccessful. The main goal of this study was to evaluate the in vitro susceptibilities to clofazimine of 209 isolates consisting of different NTM species isolated in Beijing, China. Furthermore, 47 reference strains were also tested, including 30 rapidly growing mycobacterium (RGM) species and 17 slowly growing mycobacterium (SGM) species. The potential molecular mechanism contributing to clofazimine resistance of NTM was investigated as well. Clofazimine exhibited excellent activity against both reference strains and clinical isolates of different SGM species, and most of the strains had MICs far below 1 μg/ml. Although the majority of the clinical isolates of Mycobacterium abscessus and Mycobacterium fortuitum had MICs higher than 2 μg/ml, 17 out of the 30 reference strains of different RGM species had MICs below 1 μg/ml in vitro . According to the MIC distributions, the tentative epidemiological cutoff (ECOFF) values for Mycobacterium kansasii , Mycobacterium avium , and Mycobacterium intracellulare were defined at 0.5 μg/ml, 1 μg/ml, and 2 μg/ml, respectively. Intriguingly, single-direction cross-resistance between bedaquiline- and clofazimine (Cfz)-resistant isolates was observed among the tested NTM species. This study demonstrates that clofazimine had strong activity against most SGM species in vitro , as well as some RGM species. The data provide important insights into the possible clinical application of Cfz to treat NTM infections.

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