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Evaluation of filter paper as a means of transporting inactivated Gram-negative non-fermentative bacteria and Haemophilus spp. for identification using the MALDI-TOF MS system |
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| Authors: | M.S. Carneiro M.N. Crispim C.M. Wilhelm F.C.Z. Volpato A.L. Barth |
| Affiliation: | 1. LABRESIS—Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil;2. LABRESIS—Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil PPGCF—Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil;3. LABRESIS—Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil PPGCM—Programa de Pós-Graduação em Ciências Médicas, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil;4. LABRESIS—Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil PPGCF—Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil PPGCM—Programa de Pós-Graduação em Ciências Médicas, Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil |
| Abstract: | This study aimed to evaluate the filter paper as a means to transport inactivated Gram-negative non-fermentative (GNNF) bacteria and Haemophilus spp. for analysis using MALDI-TOF MS. A total of 133 isolates were evaluated and the analysis of each isolate was performed directly from original bacterial colony and in filter paper after the processing. To evaluate the agreement between the identification performed directly from the colony and after impregnation in filter paper, we assign the scores: >2·3 as excellent (E); 2·0 to 2·3 as very good (VG); 1·7–1·99 as good (G); <1·7 as unidentified (U). The divergences were classified as: Minor Divergence, Intermediate Divergence and Major Divergence. A total of 80 isolates transported in the filter paper disks presented full category concordance; 39 isolates presented Minor Divergence; 4 isolates present Intermediate Divergence; 4 isolates present Major Divergence and 6 isolates present better results after impregnation in filter paper. The proposed methodology of bacteria transportation presented a sensitivity of 96·9% and a specificity of 100%. The filter paper as a means to transport and storage of inactivated GNNF and Haemophilus spp. may be considered a potential tool for faster, more accurate, biosafe and less-expensive identification. |
| Keywords: | filter paper Gram-negative non-fermentative Haemophilus spp. MALDI-TOF MS transport bacteria |