scholarly journals Dermatophyte susceptibilities to antifungal azole agents tested in vitro by broth macro and microdilution methods

Author(s):  
Emerson Roberto Siqueira ◽  
Joseane Cristina Ferreira ◽  
Reginaldo dos Santos Pedroso ◽  
Marco Aurélio Sicchiroli Lavrador ◽  
Regina Celia Candido

The in vitro susceptibility of dermatophytes to the azole antifungals itraconazole, fluconazole and ketoconazole was evaluated by broth macro and microdilution methods, according to recommendations of the CLSI, with some adaptations. Twenty nail and skin clinical isolates, four of Trichophyton mentagrophytes and 16 of T. rubrum were selected for the tests. Itraconazole minimal inhibitory concentrations (MIC) varied from < 0.03 to 0.25 µg/mL in the macrodilution and from < 0.03 to 0.5 µg/mL in the microdilution methods; for fluconazole, MICs were in the ranges of 0.5 to 64 µg/mL and 0.125 to 16 µg/mL by the macro and microdilution methods, respectively, and from < 0.03 to 0.5 µg/mL by both methods for ketoconazole. Levels of agreement between the two methods (± one dilution) were 70% for itraconazole, 45% for fluconazole and 85% for ketoconazole. It is concluded that the strains selected were inhibited by relatively low concentrations of the antifungals tested and that the two methodologies are in good agreement especially for itraconazole and ketoconazole.

2010 ◽  
Vol 5 (6) ◽  
pp. 821-826
Author(s):  
Monika Staniszewska ◽  
Beata Rozbicka ◽  
Aleksandra Rajnisz ◽  
Ewa Bocian ◽  
Ewa Wasińska ◽  
...  

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.


2001 ◽  
Vol 43 (5) ◽  
pp. 267-270 ◽  
Author(s):  
Sydney Hartz ALVES ◽  
Loiva T. OLIVEIRA ◽  
Jane M. COSTA ◽  
Irina LUBECK ◽  
Agnes Kiesling CASALI ◽  
...  

The purpose of the present study was to compare the susceptibility to four antifungal agents of 69 Cryptococcus neoformans strains isolated from AIDS patients with that of 13 C. neoformans strains isolated from the environment. Based on the NCCLS M27-A methodology the Minimal Inhibitory Concentrations (MICs) obtained for amphotericin B, itraconazole and ketoconazole were very similar for clinical and environmental isolates. Clinical isolates were less susceptible to fluconazole than environmental isolates. The significance of these findings and aspects concerning the importance, role and difficulties of C. neoformans susceptibility testing are also discussed.


1992 ◽  
Vol 11 (11) ◽  
pp. 1069-1073 ◽  
Author(s):  
K. Watanabe ◽  
K. Ueno ◽  
N. Kato ◽  
Y. Muto ◽  
K. Bandoh ◽  
...  

1994 ◽  
Vol 5 (suppl c) ◽  
pp. 3C-8C ◽  
Author(s):  
Donald E Low ◽  
Lionel A Mandell

This prospective. single open-label sludy was conducted in 14 Canadian centres to assess lhe efncacy of I g, once a day intravenous ceftriaxone treatment administered for a minimum of three days in patients with lower respiratory tract infection. There were 137 patients enrolled. Age varied between 19 and 95 years (mean 68 years). Mosl patients (91 %) were diagnosed with community acquired pneumonia without bacteremia. Most of the cases (82%) were defined as modcralc or severe. Patients received ceftriaxone treatment for an average or five days. Macrolidcs or metronidazole were administered concomitantly wilh ceftriaxone in 34 patienls (25%). After a minimum of three days of ceftriaxone treatment. 59 palicnls (43%) were switched to oral antibiotics. Favourable treatment outcome was found in 92.9% and treatment failure (including relapse of infection) in 7.1 % o lpalicnls. Evaluable patients accounted for 91 % of patients enrolled in the study. Clinical cure and clinical improvement were achieved in 64.6 and 28.3% of the evaluable patients. respectively. Relapse of infection occurred in two patients (1.8%). and treatment failure was recorded in six cases (5.3%). Twelve patients (8.8%) died clue to reasons unrelated to the sludy treatment. Three adverse event (hives, diarrhea and phlebitis at the injection site) were possibly related to the study drug. A cross-Canada in vitro susceptibility surveillance study of bacterial pathogens. frequently the cause of pneumonia. found ceftriaxone to have minimal inhibitory concentrations in 90% of isolates that would support such a dosing regimen. with the exception of Enterobacter species. These rcsults support the use of 1 g, once daily ceftriaxone for the empirical treatment of pneumonia in those patients requiring hospitalization.


2001 ◽  
Vol 45 (6) ◽  
pp. 1919-1922 ◽  
Author(s):  
Arthur L. Barry ◽  
Peter C. Fuchs ◽  
Steven D. Brown

ABSTRACT The in vitro activity of daptomycin is affected by the concentration of calcium cations in the test medium. Mueller-Hinton broth is currently adjusted to contain 10 to 12.5 mg of magnesium per liter and 20 to 25 mg of calcium per liter, but for testing of daptomycin, greater concentrations of calcium (50 mg/liter) are recommended to better resemble the normal concentration of ionized calcium in human serum. Two levels of calcium were used for broth microdilution tests of 2,789 recent clinical isolates of gram-positive bacterial pathogens. MICs of daptomycin were two- to fourfold lower when the broth contained additional calcium. For most species, however, the percentages of strains that were inhibited by 2.0 μg of daptomycin per ml were essentially identical with the two broth media. Enterococci were the important exception; i.e., 92% were inhibited when tested in calcium-supplemented broth but only 35% were inhibited by 2.0 μg/ml without the additional calcium. This type of information should be considered when selecting criteria for defining in vitro susceptibility to daptomycin.


2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S793-S793
Author(s):  
Lynn-Yao Lin ◽  
Dmitri Debabov ◽  
William Chang

Abstract Background OXA-48 is a carbapenemase with low-level hydrolytic activity toward cephalosporins. This study evaluated in vitro activities of ceftazidime-avibactam (CAZ-AVI), meropenem (MEM), meropenem-vaborbactam (MVB), ceftolozane-tazobactam (C/T), and other antimicrobial agents against 113 OXA-48-producing Enterobacterales with multiple resistance mechanisms collected in a 2017–2018 global surveillance program. Methods Nonduplicate clinical isolates of 113 Enterobacterales were collected from medical centers in 25 countries in 2017–2018. In vitro susceptibility tests were performed by broth microdilution with a custom-made panel consisting of CAZ-AVI, ceftazidime (CAZ), MEM, MVB, C/T, colistin (COL), gentamicin (GEN), levofloxacin (LEV), and amikacin (AMK). Whole genome sequencing or quantitative PCR data were used to analyze resistance mechanisms, such as OXA-48, extended-spectrum β-lactamase (ESBL), original-spectrum β-lactamase (OSBL), and AmpC β-lactamase. Clinical and Laboratory Standards Institute breakpoints were applied for susceptibility interpretations. Results Of 113 OXA-48–producing clinical isolates, 20 carried OXA-48 alone. The remaining 93 isolates carried additional β-lactamases, including 63 with ESBL (CTX-M-15) + OSBL (SHV, TEM), 15 with AmpC (DHA, AAC, CMY) + ESBL (CTX-M-15), and 15 with OSBL (SHV, TEM). 99.1% (all but 1) of all isolates tested were susceptible to CAZ-AVI, whereas 71.7%, 17.7%, and 14.2% were susceptible to MVB, MEM, and C/T, respectively. Among isolates harboring multiple resistance mechanisms (OXA-48 + ESBL + OSBL; n=63), 98.4%, 69.8%, 11.1%, and 7.9% were susceptible to CAZ-AVI, MVB, MEM, and C/T, respectively. Among isolates carrying OXA-48 + AmpC + ESBL + OSBL (n=15), 100%, 66.7%, 13.3%, and 13.3% were susceptible to CAZ-AVI, MVB, MEM, and C/T, respectively (Table). Aminoglycosides (AMK and GEN) and other β-lactams (eg, CAZ) were 20%–90% active against these isolates. COL was the second most effective comparator, inhibiting 83.2% of these isolates. Table Conclusion CAZ-AVI was the most effective agent in this study compared with other antibiotics, including β-lactams, β-lactam–β-lactamase inhibitor combinations, aminoglycosides, and COL, against OXA-48-producing Enterobacterales carrying multiple β-lactamases. Disclosures Lynn-Yao Lin, MS, AbbVie (Employee) Dmitri Debabov, PhD, AbbVie (Employee) William Chang, BS, AbbVie (Employee)


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