Polypeptides obtained from gram negative microbes

A first composition comprising:

• at least two siderophore receptor polypeptides (SRPs) isolated from a gram negative microbe;
• at least two porins isolated from the gram negative microbe;
• and
• lipopolysaccharide (LPS), wherein the concentration of LPS is no greater than the concentration of LPS in a second composition comprising:
• the at least two siderophore receptor polypeptides isolated from the gram negative microbe;
• the at least two porins isolated from the gram negative microbe;
• and
• lipopolysaccharide;
• wherein the second composition is produced by a process comprising:
• providing the gram negative microbe;
• disrupting the gram negative microbe in a buffer;
• solubilizing the disrupted gram negative microbe for greater than about 24 hours in a solution comprising sarcosine to result in solubilized and insoluble cellular material, wherein a ratio of the sarcosine to gram weight of disrupted gram negative microbe is between about 0.8 gram sarcosine per about 4.5 grams of disrupted gram negative microbe and about 1.2 grams sarcosine per about 4.5 grams of disrupted gram negative microbe;
• and
• isolating molecules of the gram negative microbe, wherein the isolated molecules comprise the at least two SRPs, the at least two porins, and LPS.