Question

pathogenic bacteria present in e.g a blood sample can be identified by culture independent methods. Describe these methods within each of these categories

Answer 1

Answer=

pathogenic bacteria present in e.g a blood sample can be identified by culture independent methods are as follows:

1]Hybridization-Fluorescent in situ hybridization (FISH) is among the most studied commercial techniques suitable for the detection of pathogens in positive blood cultures.

in only2-3 hours ,FISH may identify more than 95% of bacteria & yeasts commonly found in blood

slides of positive blood culture are prepared ,hybridized with fluorochrome labelled oligonucleotide probes targeted to rRNA & visualized microscopically.

2]DNA amplification=PCR is the most commonly applied technique for the detection of pathogens from positive blood culture.commercially available tests use either broad range PCR or multiplex PCR.

3]Broad range amplification=

They uses primers that recognize conserved sequences of bacterial /fungal chromosomal genes encoding ribosomal DNA.

Hyplex Blood screen is a multiplex PCR assay with subsequent identification of bacterial species.

from positive blood culture using hybridization in an ELIZA -like format .

4]Mass spectroscopy=matrix-associated laser desorption /ionization (MALDI) time-of-flight mass spectroscopy has been used successfully for routine identification of bacterial colonies & for direct identification of bacteria in positive blood culture.