engleski

Differentiation between Pseudomonas and Stenotrophomonas Species Isolated from Fish Using Molecular and MALDI-TOF Method

For the purpose of precise antibiotic susceptibility testing it is necessary to clearly distinguish Pseudomonas and Stenotrophomonas genera, considering acquired resistance of Pseudomonas species, as well as the intrinsic resistance of Stenotrophomonas species. This is why in the identifi cation of the 51 isolates originated from fi sh, the following methods were used: standard PCR, 16S rRNA gene sequencing, and MALDI-TOF. The results of the standard PCR test, 16S rRNA gene sequencing and MALDI-TOF analysis confi rmed 35 strains to belong to the Pseudomonas genus. Standard PCR test and VITEK MS device confi rmed that 10 strains belong to Stenotrophomonas maltophilia species. Three strains were positive in both standard PCR tests for Pseudomonas and Stenotrpohomonas. 16S rRNA gene sequencing identifi ed these 3 strains to be 99% Pseudomonas sp. and 99% Stenotrophomonas sp. VITEK MS fi rst identifi ed these three strains as 99% Stenotrophomonas, and in the repeated identifi cation it identifi ed them as 99% Pseudomonas. MALDI TOF/TOF 4800 Plus device identifi ed these strains as Stenotrophomonas. Three strains were negative in both standard PCR tests for Pseudomonas and Stenotrpohomonas. 16S rRNA gene sequencing identifi ed these 3 strains to be 99% Pseudomonas sp. and 99% Stenotrophomonas sp. VITEK MS fi rst identifi ed these three strains as 99% Stenotrophomonas, and in the repeated identifi cation it identifi ed them as 99% Pseudomonas. MALDI TOF/TOF 4800 Plus device identifi ed these strains as Stenotrophomonas. Although modern test methods that have very high specifi city (PCR, 16S rRNA gene sequencing, MALDI TOF) were used in this study, precise differentiation between Aksentijević et al.: Differentiation between Pseudomonas and Stenotrophomonas species isolated from fi sh using molecular and MALDI- TOF method 305 Pseudomonas and Stenotrophomonas species for 6 isolates could not be reached using the above mentioned methods.

fish ; PCR16S ; rRNA ; MALDI-TOF

nije evidentirano