Your poster should report the latest research findings for a particular pathogen in one key aspect, namely, diagnostics, virulence factors, treatments or vaccine development, with an immunological or microbiological overview (or both). As the content of the poster is not your own research, it is a review poster and it is not expected to have major sections on material and methods.
Your poster should contain something like the following:-

Title:

..............which appropriately describes what the poster is about for a named pathogen.

Introduction:

...... which gives general/ background information about the pathogen and the disease(s) it causes. The introduction should be no more than 10-20% of the poster's content.

The rest of the poster:

........... should deal with the particular aspect chosen for the named pathogen reporting in general terms any methods used, plus the results and discussion on the topic.

Conclusion:

.......... sums up the work and makes a critical statement about the validity of the work and it's possible benefits.