[1] A number of Morganellaceae bacterial species are opportunistic human pathogens, including Proteus, Providencia, and occasionally Morganella in nosocomial settings.

Three Proteus species P. vulgaris, P. mirabilis, and P. penneri are opportunistic human pathogens, most commonly resulting in urinary tract infections.

As a result of this highly effective evolutionary strategy, entomopathogenic nematodes are commonly used as biological control agents against insect pests like corn rootworms.

[9] The fly immune system defends against this infection using a highly specific antimicrobial peptide that is required for defence against P. rettgeri, but not other Providencia species.

Seven conserved signature indels (CSIs) were identified for this family through genomic analyses in the proteins dihydrolipoamide succinyltransferase, Xaa-Pro dipeptidase, bifunctional UDP-sugar hydrolase (5'-nucleotidase), transcriptional repair coupling factor, phosphate acetyltransferase, histidine–tRNA ligase, and N-acetylmuramoyl-L-alanine amidase.

The original assignment of species into the family Enterobacteriaceae was largely based on 16S rRNA genome sequence analyses, which is known to have low discriminatory power and the results of which changes depends on the algorithm and organism information used.