How a rare bacterium ended up in a dialysis patient’s abdomen?
At first glance, it seemed like a routine medical case; a patient with chronic kidney disease developed abdominal pain and fever. But what doctors discovered turned out to be anything but ordinary.
This very rare case was described by Shohei Fukunaga, Naohito Masuda, Daisuke Nakashima, Rina Oba, Maiko Furuya, Satoshi Kidoguchi, Yudo Tanno, and Takashi Yokoo in the case report “Pantoea septica-associated peritoneal dialysis-related peritonitis: first case report.”
A man in his 50s, who had recently started peritoneal dialysis, arrived at the hospital with typical signs of peritonitis, a serious inflammation of the lining of the abdomen. This method of treatment allows patients to perform dialysis at home, using their own abdominal lining as a natural filter. A special fluid is introduced into the abdomen through a small catheter, where it absorbs waste products from the blood before being drained and replaced after a few hours. Yet this same catheter also provides a potential entry point for bacteria from the environment. In this case, laboratory analysis revealed an unexpected culprit: the bacterium Pantoea septica. It is commonly found in soil and on plants, and only rarely causes infections in humans. More importantly, it has not previously been linked to infections in patients undergoing peritoneal dialysis.
“P. septica is a Gram-negative rod belonging to the Enterobacteriaceae family. Although it is not part of the human intestinal flora, it is widely distributed in the environment, including soil and plants. While primarily recognized as a plant pathogen, it can also act as an opportunistic pathogen in humans. The most common clinical manifestation is bloodstream infection due to exposure to P. septica-contaminated medical equipment or fluid, but respiratory, intra-abdominal, and soft tissue infections have also been reported. However, to date, no case of PD-related peritonitis caused by P. septica has been described,” the scientists explained.
One detail from the patient’s home environment caught the doctors’ attention
Although the exact source of the infection could not be confirmed, one detail from the patient’s home environment caught the doctors’ attention: his mother was engaged in gardening. “In the present case, the patient’s mother was engaged in gardening at home, raising the possibility that P. septica was present in the home environment. As PD was initiated only 1 month earlier, the patient may have been unfamiliar with the bag connection technique. Therefore, the infection was presumed to have been caused by contamination from the soil- or plant-associated P. septica. However, environmental cultures from the patient’s home (e.g., soil or plants) were not performed; thus, the source of infection could not be confirmed,” they noted. If strict hygiene is not maintained during the exchange of dialysis bags, such microorganisms can find their way into the body.
The patient was treated with antibiotics to which the bacterium was susceptible and made a full recovery after three weeks of therapy. The significance of this case lies in the fact that it represents the first recorded example of this type of infection.
The first reported case of PD-related peritonitis caused by P. septica
“To our knowledge, this is the first reported case of PD-related peritonitis caused by P. septica. As P. septica is an environmental bacterium, strict adherence to hand hygiene and proper PD bag exchange techniques are essential to prevent infection. In cases of infection, antimicrobial susceptibility testing should be performed, and targeted antibiotic therapy must be administered for approximately 3 weeks.” Fukunaga et al., 2026.
For clinicians, it is a reminder that the sources of infection are not always where we expect them to be. For patients, it highlights that while peritoneal dialysis offers freedom, it also demands discipline. In situations where even seemingly harmless contact with the environment can pose a risk, hygiene becomes the first line of defence. Sometimes, the greatest threats are not found in hospitals, but in everyday activities we consider entirely benign, like gardening.
