Evaluation and comparison of Abbott Jaffe and enzymatic creatinine methods: Could the old method meet the new requirements?

BACKGROUND: The aim of this study is to evaluate and compare the analytical performance characteristics of the two creatinine methods based on the Jaffe and enzymatic methods. METHODS: Two original creatinine methods, Jaffe and enzymatic, were evaluated on Architect c16000 automated analyzer via limit of detection (LOD) and limit of quantitation (LOQ), linearity, intra-assay and inter-assay precision, and comparability in serum and urine samples. The method comparison and bias estimation using patient samples according to CLSI guideline were performed on 230 serum and 141 urine samples by analyzing on the same auto-analyzer. RESULTS: The LODs were determined as 0.1 mg/dL for both serum methods and as 0.25 and 0.07 mg/dL for the Jaffe and the enzymatic urine method respectively. The LOQs were similar with 0.05 mg/dL value for both serum methods, and enzymatic urine method had a lower LOQ than Jaffe urine method, values at 0.5 and 2 mg/dL respectively. Both methods were linear up to 65 mg/dL for serum and 260 mg/dL for urine. The intra-assay and inter-assay precision data were under desirable levels in both methods. The higher correlations were determined between two methods in serum and urine (r=.9994, r=.9998 respectively). On the other hand, Jaffe method gave the higher creatinine results than enzymatic method, especially at the low concentrations in both serum and urine. CONCLUSIONS: Both Jaffe and enzymatic methods were found to meet the analytical performance requirements in routine use. However, enzymatic method was found to have better performance in low creatinine levels.

[Comparison of minimum inhibitory and minimum effective concentration values for the detection of in vitro susceptibilities of Aspergillus species against caspofungin]. / Aspergillus türlerinin kaspofungine karsi in vitro duyarliliginin saptanmasinda minimum inhibitör ve minimum etkili konsantrasyon degerlerinin karsilastirilmasi.

Caspofungin is a promising echinocandin-group antifungal agent used especially in the treatment of resistant invasive aspergillosis. The guidelines for in vitro susceptibility testing of Aspergillus species against caspofungin are not described by the Clinical and Laboratory Standards Institute (CLSI). The minimum inhibitory concentration that showed a prominent reduction of growth (MIC-2) and minimum effective concentration (MEC) endpoints are frequently used for the susceptibility testing of caspofungin as MIC determination criteria. The aim of this study was to evaluate the in vitro activity of caspofungin against Aspergillus species and to compare MIC-2 and MEC endpoints in the determination of MICs. A total of 32 Aspergillus species (18 A. fumigatus, seven A. flavus, five A. niger, and two A. versicolor) isolated from different clinical samples were included to the study. In vitro susceptibilities of the strains against 0.03-16 microg/ml caspofungin concentrations were searched by broth microdilution method as recommended by CLSI M-38A document, with the use of glucose supplemented 2% RPMI 1640 media. The MIC-2 and MEC endpoints were determined both at 24 and 48 hours. The concordance between MIC-2 and MEC endpoints of the strains at 24 and 48 hours incubations was found as 53% and 100%, respectively, with the difference of +/- 1 dilution. MIC-2 and MEC measurements showed the same values at the end of 48 hours, whereas 7% showed differences in +/- 1 dilution. MEC endpoints were also found to be more stable than MIC-2 in both of the incubation periods. In conclusion, MEC value is a more objective and stable endpoint and easier to use than MIC-2 for testing in vitro caspofungin activity against Aspergillus species.

Species distribution and antifungal susceptibilities of dermatophytes during a one year period at a university hospital in Turkey.

Dermatophyte infections have been considered to be a major public health problem in many parts of the world. The aim of this study was to determine the causative agents of dermatophytoses and their antifungal susceptibilities in a Turkish University Hospital, west of Turkey. A total of 926 patients suspected to have dermatophytic lesions were examined over a period of 1 year (2001-2002). Samples collected from skin, hair and nails were submitted to direct microscopical examination using KOH and Calcofluor white stain, cultured on Sabouraud dextrose agar and Mycosel agar. The prevalence of dermatophytoses was 7.34% (68/926). Trichophyton rubrum was the most frequent dermatophyte isolated (56%) followed by T. mentagrophytes (38%), T. violaceum (1.5%), T. verrucosum (1.5%), Microsporum canis (1.5%) and Epidermophyton floccosum (1.5%). Tinea pedis (47%) was the most common type of infection, followed by tinea unguium (29%), tinea inguinalis (15%), tinea corporis (7.4%) and tinea capitis (1.6%). Secondary, we have tested 68 strains of dermatophytes against four antifungal agents following mainly the National Committee for Clinical Laboratory Standards M38-P standard for filamentous fungi. In general, all antifungals were shown to be highly effective and itraconazole and naftifine appeared more active than ketoconazole and oxiconazole.

[Molecular epidemiologic surveillance and antifungal agent sensitivity of Candida albicans isolated from anesthesia intensive care units]. / Anestezi yogun bakim ünitesi hastalarindan izole edilen Candida albicans suslarinin antifungal ajanlara duyarliligi ve moleküler epidemiyolojik izlemi.

Patients in intensive care units (ICU) are at risk of nosocomial infections. The incidence of nosocomial fungal infections has increased in parallel with the increase of nosocomial infections. Candida albicans is the most frequent pathogenic species among the fungi. The aim of this study was to make an epidemiological surveillance of C. albicans urine isolates which were isolated from patients who were hospitalized in ICU between June 2000 and October 2001 by antifungal susceptibility testing and Randomly Amplified Polymorphic DNA (RAPD) analysis. For this purpose, 38 C. albicans which were isolated from 29 patients were investigated for amphotericin B and fluconazole susceptibility with the microdilution method. The range of minimal inhibitory concentration (MIC) of amphotericin B was between 0.25-1 microgram/ml and MIC50 value was 0.5 microgram/ml and none of the isolates had high (MIC > 1 microgram/ml) MIC values. The MIC values for fluconazole varied between 0.25-16 micrograms/ml and MIC50 value was 1 microgram/ml. While none of the isolates was resistant to fluconazole, two isolates were detected as dose dependent susceptible. RAPD analysis was performed with two different primers in order to investigate clonal relationship, and 22 patterns were detected with one of the primers and 24 patterns were detected with the other. In conclusion, it is thought that the origin of the C. albicans urine isolates were mostly endogenous but exogenous spread might also be considered as isolates that were clonally related were isolated from different patients at the same time interval.