Identification and molecular characterization of Roseomonas genomospecies 5 isolated from Umbilical Cord Blood Unit

Introduction

Roseomonas is rarely involved in pathology but represents an important case of contamination when is associated to hematopoietic stem cells, having intrinsic resistance to multiple classes of antibiotics and the ability to gain new resistance factors. This is a report that follows a previous identification of contamination microorganisms in the cryopreserved Umbilical Cord Blood Units (UCBU) stored in the Cord Blood Bank (CBB) of the National Center of Blood Transfusion (NCBT) at Mexico City.

Objective

Phenotypic and molecular characterization of Roseomonas genomospecies 5 isolated from UCBU.

Materials and methods

Phenotypic enzyme diffusion tests in solid phase (proteases, amylases, hemolysins and lipases detection) and antimicrobials (for Gram negative bacteria) resistance tests were performed to determine the potential virulence and resistance of the strain isolated of the Umbilical Cord Blood Unit 2191. Additional PCR assays were performed to determine the presence of genetic elements associated to antimicrobial resistance: bla genes and Class 1 integrons. Also, a 16S rRNA gene sequence analysis was done on microbial strains isolated from UCBU.

Results

Broad-spectrum penicillins, third generation cephalosporins, and fluoroquinolones did not show inhibitory activity in the 2191 strain. We could only identify extracellular amylase activity. Gene detection by PCR of encoding antimicrobial resistance (β-lactamases) and Class 1 integrons revealed the presence of bla_–HSV and bla_–TEM variants in the 2191 strain. Phylogenetic analysis revealed the presence of Roseomonas genomospecies 5 in the 2191 UCBU (named 2191 strain).

Conclusions

This is the first report on the isolation of Roseomonas genomospecies 5 in a UCBU for transplantation, an unusual bacteria isolated from umbilical cord blood, associated with a possible immunosuppression in the donor. Its presence in UCBU can be fatal in immunocompromised patients if it were used for transplantation of Hematopoietic Stem Cells (HSC), due to the potential virulence of the strains and the resistance to antimicrobials commonly used.