Thesis
Detección genética de agentes etiológicos bacterianos de infección intrahospitalaria en muestras clínicas con cultivo negativo
Autor
Q.B.P. Hernández Martínez, Fabiola
Institución
Resumen
Hospital-acquired infections are defined as infections not present and without evidence of
incubation at the time of admission to a healthcare setting. Detection and identification of
pathogen bacteria from clinical samples is commonly performed employing traditional
phenotypic techniques that depend on culture, which has several disadvantages. Nowadays,
molecular techniques are being implemented as alternative diagnostic tools for troubleshooting
samples; one of them, the direct sequencing of 16S rRNA gene offers a faster diagnosis
avoiding the culture’s disadvantages. The aim of the present work was to detect bacterial
pathogens from samples with negative cultures by means of the direct amplification and
sequencing of 16S rRNA gene. 300 samples were gathered in Centro Médico Nacional “20 de
Noviembre” from ISSSTE. The amplification of 16S rRNA was performed and those samples
with a positive amplification were purified and sequenced. The electropherograms were
analized with BLAST (for monocrobial infections) and with RipSeq Web Tool (ISENTIO®) for
polybacterial infections. 23 positive samples were detected; all of them were monomicrobial
infections and previously described pathogens as E. coli, P. aeruginosa, Enterococcus sp. and
coagulase-negative staphylococci were detected. Uncommon pathogens were also detected,
Corynebacterium sp., Kokuria sp., Leuconostoc sp. and Achromobacter xylosoxidans. These
findings show the importance of the use of molecular methods for identification of such
bacteria, that are not generally studied and that cause infections in inmunocomrpomised
patients.