Laboratory screening method for selection of healthy volunteers

1990 ◽  
Vol 39 (5) ◽  
Author(s):  
M. Sibille ◽  
D. Vital Durand
2017 ◽  
Vol 61 (12) ◽  
Author(s):  
L. Bernal-Martínez ◽  
H. Gil ◽  
O. Rivero-Menéndez ◽  
S. Gago ◽  
M. Cuenca-Estrella ◽  
...  

ABSTRACT The global emergence of azole-resistant Aspergillus fumigatus strains is a growing public health concern. Different patterns of azole resistance are linked to mutations in cyp51A. Therefore, accurate characterization of the mechanisms underlying azole resistance is critical to guide selection of the most appropriate antifungal agent for patients with aspergillosis. This study describes a new sequencing-free molecular screening tool for early detection of the most frequent mutations known to be associated with azole resistance in A. fumigatus. PCRs targeting cyp51A mutations at positions G54, Y121, G448, and M220 and targeting different tandem repeats (TRs) in the promoter region were designed. All PCRs were performed simultaneously, using the same cycling conditions. Amplicons were then distinguished using a high-resolution melting assay. For standardization, 30 well-characterized azole-resistant A. fumigatus strains were used, yielding melting curve clusters for different resistance mechanisms for each target and allowing detection of the most frequent azole resistance mutations, i.e., G54E, G54V, G54R, G54W, Y121F, M220V, M220I, M220T, M220K, and G448S, and the tandem repeats TR34, TR46, and TR53. Validation of the method was performed using a blind panel of 80 A. fumigatus azole-susceptible or azole-resistant strains. All strains included in the blind panel were properly classified as susceptible or resistant with the developed method. The implementation of this screening method can reduce the time needed for the detection of azole-resistant A. fumigatus isolates and therefore facilitate selection of the best antifungal therapy in patients with aspergillosis.


2005 ◽  
pp. 4167 ◽  
Author(s):  
Edel M. Minogue ◽  
Tammy P. Taylor ◽  
Anthony K. Burrell ◽  
George J. Havrilla ◽  
Benjamin P. Warner ◽  
...  

2010 ◽  
Vol 1 (2) ◽  
pp. 165-174 ◽  
Author(s):  
S. Reimann ◽  
F. Grattepanche ◽  
C. Baggenstos ◽  
E. Rezzonico ◽  
B. Berger ◽  
...  

An efficient screening method for selection of Bifidobacterium longum strains resistant to spray drying and storage was developed based on randomly amplified polymorphic DNA (RAPD) for identification of the best survivors in mixed strains bacterial preparations. Three different primers were used to generate RAPD profiles of 22 B. longum strains. All strains were distinguished according to their RAPD profiles except for the strain NCC2705 and its H2O2 resistant derivative variant. The 22 strains were grouped in 3 batches of 7, 7 and 8 strains and subjected to spray drying and storage at 30 and 37 °C under anaerobic conditions. Batch survival rates after spray drying reached 17.1±4.4%. Strains showing the highest prevalence and/or resistance to storage at 37 °C were selected from individual batches for subsequent spray drying and storage testing. After 67 days of storage, NCC572 was identified as the dominant strain in powder. The stability of strain NCC572 was confirmed by performing single spray drying and storage tests. Out of 22 B. longum strains, a robust strain was identified by combining RAPD with a simultaneous screening test for survival under spray drying and storage. The method allowed a fast screening of B. longum strains in mixture for resistance to spray drying and storage compared to traditional screening procedures carried out with individual strains, in the same conditions. This approach could be applied to other stress conditions.


1994 ◽  
Vol 41 (4) ◽  
pp. 319-325 ◽  
Author(s):  
Jelena Kuldova ◽  
Ivan Hrdy ◽  
Zdeně Wimmer

2005 ◽  
Vol 73 (2) ◽  
pp. 972-980 ◽  
Author(s):  
C. G. Osorio ◽  
J. A. Crawford ◽  
J. Michalski ◽  
H. Martinez-Wilson ◽  
J. B. Kaper ◽  
...  

ABSTRACT We have constructed an improved recombination-based in vivo expression technology (RIVET) and used it as a screening method to identify Vibrio cholerae genes that are transcriptionally induced during infection of infant mice. The improvements include the introduction of modified substrate cassettes for resolvase that can be positively and negatively selected for, allowing selection of resolved strains from intestinal homogenates, and three different tnpR alleles that cover a range of translation initiation efficiencies, allowing identification of infection-induced genes that have low-to-moderate basal levels of transcription during growth in vitro. A transcriptional fusion library of 8,734 isolates of a V. cholerae El Tor strain that remain unresolved when the vibrios are grown in vitro was passed through infant mice, and 40 infection-induced genes were identified. Nine of these genes were inactivated by in-frame deletions, and their roles in growth in vitro and fitness during infection were measured by competition assays. Four mutant strains were attenuated >10-fold in vivo compared with the parental strain, demonstrating that infection-induced genes are enriched in genes essential for virulence.


2017 ◽  
Vol 61 (12) ◽  
Author(s):  
J. B. Buil ◽  
H. A. L. van der Lee ◽  
A. J. M. M. Rijs ◽  
J. Zoll ◽  
J. A. M. F. Hovestadt ◽  
...  

ABSTRACT Antifungal susceptibility testing is an essential tool for guiding therapy, although EUCAST and CLSI reference methods are often available only in specialized centers. We studied the performance of an agar-based screening method for the detection of azole resistance in Aspergillus fumigatus cultures. The VIPcheck consists of four wells containing voriconazole, itraconazole, posaconazole, or a growth control. Ninety-six A. fumigatus isolates were used. Thirty-three isolates harbored a known resistance mechanism: TR34/L98H (11 isolates), TR46/Y121F/T289A (6 isolates), TR53 (2 isolates), and 14 isolates with other cyp51A gene point mutations. Eighteen resistant isolates had no cyp51A-mediated azole resistance. Forty-five isolates had a wild-type (WT) azole phenotype. Four technicians and two inexperienced interns, blinded to the genotype/phenotype, read the plates visually after 24 h and 48 h and documented minimal growth, uninhibited growth, and no growth. The performance was compared to the EUCAST method. After 24 h of incubation, the mean sensitivity and specificity were 0.54 and 1.00, respectively, with uninhibited growth as the threshold. After 48 h of incubation, the performance mean sensitivity and specificity were 0.98 and 0.93, respectively, with minimal growth. The performance was not affected by observer experience in mycology. The interclass correlation coefficient was 0.87 after 24 h and 0.85 after 48 h. VIPcheck enabled the selection of azole-resistant A. fumigatus colonies, with a mean sensitivity and specificity of 0.98 and 0.93, respectively. Uninhibited growth on any azole-containing well after 24 h and minimal growth after 48 h were indicative of resistance. These results indicate that the VIPcheck is an easy-to-use tool for azole resistance screening and the selection of colonies that require MIC testing.


2013 ◽  
Vol 31 (3) ◽  
pp. 366-370 ◽  
Author(s):  
Hyang Young Joung ◽  
Mok Pil Choi ◽  
Kyung Sook Han ◽  
Su Kim ◽  
Dae Hoe Goo ◽  
...  

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