One of the key issues pertaining to the control of memory is to respond to a 
consistently changing environment or microbial niche present in it. Human cyclic 
AMP response element binding protein (CREB) transcription factor which plays a 
crucial role in memory has a homolog in C. elegans, crh-1. crh-1 appears to 
influence memory processes to certain extent by habituation of the host to a 
particular environment. The discrimination between the pathogen and a 
non-pathogen is essential for C. elegans in a microbial niche which determines 
its survival. Training the nematodes in the presence of a virulent pathogen (S. 
aureus) and an opportunistic pathogen (P. mirabilis) separately exhibits a 
different behavioural paradigm. This appears to be dependent on the CREB 
transcription factor. Here we show that C. elegans homolog crh-1 helps in memory 
response for a short term against the interacting pathogens. Following 
conditioning of the nematodes to S. aureus and P. mirabilis, the wild type 
nematodes exhibited a positive response towards the respective pathogens which 
diminished slowly after 2h. By contrast, the crh-1 deficient nematodes had a 
defective memory post conditioning. The molecular data reinforces the importance 
of crh-1 gene in retaining the memory of nematode. Our results also suggest that 
involvement of neurotransmitters play a crucial role in modulating the memory of 
the nematode with the assistance of CREB. Therefore, we elucidate that CREB is 
responsible for the short term memory response in C. elegans against bacterial 
pathogens.