食品加工および技術ジャーナル

概要

Molecular Characterization of Klebsiella Isolates from Enteral Diets

Pereira SCL and Vanetti MCD

To evaluate the genotyping of Klebsiella isolates from enteral diets in public hospitals, as high-resolution support within epidemiological surveillance for controlling nosocomial infections. Methods: Klebsiella isolates were obtained from enteral diets at two public hospitals in the state of Minas Gerais, Brazil. These isolates were identified and serotyped. Total DNA of Klebsiella was extracted and subjected to three genotyping methods, to evaluate polymorphism between the strains and genetic diversity. Results: Twenty-one isolates of Klebsiella were obtained from the hospital enteral formulae; fifteen were identified as K. pneumoniae and six as K. oxytoca. The results from random amplified polymorphic DNA (RAPD) and 16S-23S rDNA analysis revealed high polymorphism among the K. pneumoniae isolates and a low level of polymorphism among the K. oxytoca isolates. The 1420 base pairs of DNA fragments generated through amplification of the 16S rDNA region and digestion with eight restriction endonucleases resulted in identical restriction fragment length polymorphism (RFLP) patterns for all isolates. Conclusion: Our data demonstrate that RAPD and 16S-23S rDNA analyses provide more reliable estimates of the genetic diversity among Klebsiella isolates than does amplification of the 16S rDNA gene. Therefore, we recommend that RAPD typing should be the preliminary method for fast and inexpensive investigation and that 16S-23S rDNA typing should be a confirmatory method if needed.