Discussion:
R. planticola is an aerobic, gram-negative rod predominantly found in water and soil. It was previously known as Klebsiella planticola but in 2001, it was later reclassified in the new genus of Raoultella, partly due to its histamine-producing properties. R. planticola is generally innocuous and rarely causes infection in humans. (4) The first reported infection was in 1986, but there has been an increasing number of associated reports since the year 2000. (5) The incidence of R. planticola infection might have previously been underestimated due to the difficulty in isolating the bacterium and confusion with other bacteria, including Klebsiella spp.
R planticola has been a cause for pneumonia, urinary tract infection, cholangitis, conjunctivitis, peritonitis, necrotizing fasciitis, bacteraemia, cellulitis, and soft tissue infection in both adult and paediatric populations. Shotaro Yamamoto et al., found 34 cases of R. planticola bacteraemia in their review of the literature in 2018. According to their findings, 70.6% patients with R planticola infection had a malignancy. Haematological malignancies and biliary tract neoplasms comprised of 29.2%, pancreatic neoplasms were 16.7%, and others were 25.0%. They opined that the immunocompromised state either due to malignancy itself or with the associated chemotherapy appeared to be associated with the development of R. planticola bacteraemia. (6)
R. planticola is sensitive to a wide range of antibiotics except Ampicillin. However, a few articles have suggested that the bacteria develop antibiotic resistance especially with the Carbapenems which have led to severe infections. (7, 8) The mechanism of its pathogenesis remains unclear in humans given the limited data availability. Immunocompromised state, proton pump inhibitor use, and chemotherapy increase the chances of infection. (9) R planticola infection can occur when poorly cooked sea food has been consumed in a large quality and has affected various human organs, with no inclination towards a particular organ system. (10)