Pantoea

Pantoea is a genus of Gram-negative, rod-shaped bacteria in the family Erwiniaceae. The genus includes multiple species that are commonly found in plants, soil, and water. Many members are associated with plants as endophytes or pathogens, while others are considered environmental residents. Several species can act as opportunistic pathogens in humans, typically affecting individuals with compromised immune systems or those exposed to contaminated medical equipment.

Species and characteristics vary, but Pantoea organisms are generally non-spore-forming, motile with peritrichous flagella, and oxidase-negative. They are catalase-positive and usually ferment glucose, with lactose fermentation being variable. They may present on routine media as non-lactose fermenters or slow fermenters and can be misidentified as related enteric bacteria without precise testing. The genus contains several notable species, including Pantoea agglomerans and Pantoea ananatis, which have been implicated in plant diseases and, occasionally, human infections.

Ecology and clinical relevance are the two main contexts for Pantoea. In plants, several species cause diseases such as soft rot, leaf spots, or stalk and grain disorders, contributing to crop losses. In humans, Pantoea species are considered opportunistic pathogens, capable of causing bacteremia, wound infections, endocarditis, urinary tract infections, and catheter-associated infections, particularly in hospital settings. Outbreaks have been linked to contaminated intravenous products or parenteral nutrition solutions, underscoring the importance of precise identification and susceptibility-guided therapy.

Laboratory identification relies on a combination of Gram stain results, biochemical testing, and modern methods such as MALDI-TOF mass spectrometry or 16S rRNA sequencing. Antibiotic susceptibility testing is essential due to variable resistance patterns. Treatment is guided by the susceptibility profile and often involves beta-lactams or other agents effective against Gram-negative, non-fermenting or slow-fermenting Enterobacterales.