ABSTRACT
[This corrects the article DOI: 10.1371/journal.pone.0152310.].
ABSTRACT
Following the declaration by the World Health Organization (WHO) of human cases of infection with a new influenza A(H1N1)v virus of swine origin, the Turkish Ministry of Health launched a case-based reporting of influenza A(H1N1)v throughout the country on 27 April 2009. The index case was detected on 15 May 2009. As of 17 July 2009 the number of laboratory-confirmed cases of influenza A(H1N1)v totaled 128 of whom 38 were indigenous cases.
Subject(s)
Influenza A Virus, H1N1 Subtype , Influenza, Human/epidemiology , Adolescent , Adult , Aged , Child , Child, Preschool , Female , Humans , Infant , Infant, Newborn , Influenza A Virus, H1N1 Subtype/pathogenicity , Influenza, Human/diagnosis , Influenza, Human/physiopathology , Male , Middle Aged , Population Surveillance/methods , Reverse Transcriptase Polymerase Chain Reaction , Travel , Turkey/epidemiology , Young AdultABSTRACT
We evaluated a new microtiter assay for antifungal susceptibility testing based on a colorimetric reaction to monitor fungal substrate utilization. This new method (rapid susceptibility assay [RSA]) provides quantitative endpoint readings in less than 8 h compared with visual determination of MIC by the National Committee for Clinical Laboratory Standards (NCCLS) broth microdilution method, which requires a minimum of 48 h of incubation. In this study, we tested clinical isolates from each of the following species: Candida albicans (20 isolates), C. glabrata (20 isolates), C. krusei (19 isolates), C. tropicalis (19 isolates), and C. parapsilosis (28 isolates). RSA and NCCLS broth dilution methods were used to determine the MICs of amphotericin B, fluconazole, itraconazole, and 5-flucytosine for all 106 isolates. RPMI 1640 medium buffered with morpholinopropanesulfonic acid was used for both methods; however, glucose and inoculum concentrations in the RSA were modified. RSA MICs were determined as the lowest drug concentration that prevented glucose consumption by the organism after 6 h of incubation. MICs obtained from the RSA were compared with those obtained from the NCCLS M-27A method read at 24 and 48 h. MIC pairs were considered in agreement when the difference between the pairs was within 2 twofold dilutions. For the 106 isolates tested, amphotericin B and 5-flucytosine demonstrated the highest agreement in MICs between the two methods (100 and 98%, respectively), whereas fluconazole and itraconazole produced less favorable MIC agreement (63.2 and 61.3%, respectively). The azole MIC differences between the two methods were significantly reduced when lower inocula were used with a prolonged incubation time. This preliminary comparison suggests that this rapid procedure may be a reliable tool for the in vitro determination of MICs of amphotericin B and 5-flucytosine and warrants further evaluation.
Subject(s)
Antifungal Agents/pharmacology , Microbial Sensitivity Tests/methods , Amphotericin B/pharmacology , Colorimetry , Dose-Response Relationship, Drug , Fluconazole/pharmacology , Flucytosine/pharmacology , Itraconazole/pharmacology , Microbial Sensitivity Tests/standardsABSTRACT
The in vitro activity of voriconazole was compared to those of itraconazole and amphotericin B against the mold forms of 304 isolates of three dimorphic fungi, Blastomyces dermatitidis, Coccidioides immitis, and Histoplasma capsulatum. MICs were determined by a broth microdilution adaptation of the National Committee for Clinical Laboratory Standards M27-A procedure. RPMI 1640 medium was used for tests with voriconazole and itraconazole, whereas Antibiotic Medium 3 with 2% glucose was used for amphotericin B. Minimum fungicidal concentrations (MFCs) were also determined. Amphotericin B was active against all three dimorphic fungi, with MICs at which 90% of the isolates tested are inhibited (MIC(90)s) of 0.5 to 1 microg/ml. Itraconazole had MIC(90)s of 0.06 microg/ml for H. capsulatum, 0.125 microg/ml for B. dermatitidis, and 1 microg/ml for C. immitis. The MIC(90)s of voriconazole were 0.25 microg/ml for all three fungi. Amphotericin B was fungicidal for B. dermatitidis and H. capsulatum with MFCs at which 90% of strains tested are killed (MFC(90)s) of 0.5 and 2 microg/ml, respectively. It was less active against C. immitis, with MFCs ranging from 0.5 to >16 microg/ml. Voriconazole and itraconazole were lethal for most isolates of B. dermatitidis, with MFC(50)s and MFC(90)s of 0.125 and 4 microg/ml, respectively. Both azoles were fungicidal for some isolates of H. capsulatum, with MFC(50)s of 2 and 8 microg/ml for itraconazole and voriconazole, respectively; neither had a lethal effect upon C. immitis. Our results suggest that voriconazole possesses promising activity against these important human pathogens.
