Protocol Online logo
Top : New Forum Archives (2009-): : Microbiology

Identification of L.Mono and E.coli - (Jun/02/2014 )



would be great to receive your supportive comments as always smile.png! I have isolated Listeria monocytoegenes and E.coli and I would like to identify the strains using RT-PCR.


Is there any protocol that you could share with me ?? I am reading research papers to understand which primers to use , but is there a special kit that is used to identify the L.Mono and E.Coli?


Any help in this field and any advice on the steps i should take are greatly appreciated!


Good day!!



Moved to microbiology


Are you not more interested in pathotype than strain typing?


A lot also depends on what kind of strains it is and what exactly you want to know.


And there are some commercial kits out there but they are (as I remember it) more for the detection of specific strains (harmful strains) not really to identify strains in general.


i would be mainly interested in detecting the virulent type..for example, concerning L.Mono i read that


"Unfortunately, no reliable molecular method for prediction of L. monocytogenes virulence has been developed. PCR detection of known L. monocytogenes virulence genes, such as inlA, inlB, actA, hlyA, plcA and plcB, has not proven suitable for differentiation of virulent and avirulent isolates (Nishibori et al., 1995), as these genes are consistently found in L. monocytogenes (Jaradat et al., 2002)"..


am still looking if there would be kits to detect the virulent types of E.Coli and L Mono.


Thats what I already suspsected.. thats pathotyping!



For E. coli you should be able to find enough information yourself.... and there are many options for this.

(if you google for pathotyping E. coli you should already find enough ( look for the specific subgroups of virulent ones, ETEC for example... if you goolg efor pathogenic e.coli (and serotypes) you should be able to find a lot of information on this.... it will give you the possibility to find commercial kits to be used! There is enough of information avaible for this (+ commercial kits so that you can easly detect them).


For L monocytogenes its indeed more a problem. I dont know if there are better alternatives than the PCR detection systems.

There is a kit for it: microseq listeria monocytogenes detection kit.



I assume you already determined the bacteria using a biochemical test? or?


yes I did the biochemical test for L.Mono..but not for E.Coli yet. hmm I didnt have the budget for the kit :(  hopefully will manage this year.


thx! your comments are really so grateful :)