Editor:
A 58-year-old man with diabetic nephropathy on continuous ambulatory peritoneal dialysis (PD) for 8 years was admitted because of diarrhea, diffuse abdominal pain, and turbid dialysate for 1 day. He had no fever, chills, nausea, or vomiting.
Physical examination showed a blood pressure of 96/62 mmHg, pulse of 76 bpm, rebounding tenderness of the abdomen, and a clean exit site. The white blood cell counts of peripheral venous blood and effluent were 5100/μL and 2190/μL respectively. History showed that, 3 months earlier, this man had had chronic methicillin-resistant Staphylococcus aureus osteomyelitis of the right toe, for which he had received sodium fusidate 250 mg three times daily and sulfamethoxazole-trimethoprim 800 mg and 160 mg twice daily thereafter.
At the current presentation, the patient was admitted and received intraperitoneal ceftazidime and vancomycin empirically. On the 4th day after admission, the effluent culture revealed Citrobacter youngae and Pantoea agglomerans. A sensitivity test showed that both pathogens were sensitive to levofloxacin and aminoglycosides, but resistant to sulfamethoxazole-trimethoprim and all cephalosporins except cefepime. We changed the patient’s antibiotics to intravenous levofloxacin, and his effluent white blood cell count improved 2 days later (to 97/μL). Because of the mixed infection with enteric pathogens, we arranged abdominal computed tomography imaging, which showed no active intra-abdominal lesions. The patient completed treatment after 2 weeks of intravenous levofloxacin, followed by 1 more week of oral levofloxacin.
DISCUSSION
C. youngae and P. agglomerans belong to the gram-negative Enterobacteriaceae and are identified in human feces. Citrobacter was initially classified as genomospecies 5 of the 11 genomospecies in the C. freundii complex, later regrouped in 1993 on the basis of DNA relatedness (1). C. freundii and C. koseri are the two most common clinical isolates in Citrobacter infections (2,3). The other 9 Citrobacter species, including C. youngae, are rarely a cause of infections; overall, they accounted for only 5% of all Citrobacter infections in a 12-year survey after the regrouping (2). These non-koseri and non-freundii Citrobacter species can cause intra-abdominal infections in immunosuppressed individuals (4).
Gursu et al. recently reviewed the literature concerning peritonitis caused by Citrobacter species in PD patients, but the results were very limited because the microbiology findings and clinical outcomes were not detailed in the publications reviewed (5). Only a few cases of non-koseri and non-freundii Citrobacter peritonitis were reported, and they were successfully treated without catheter removal (6,7). To the best of our knowledge, our case is the first reported of C. youngae peritonitis.
Consensus on the treatment of Citrobacter peritonitis in PD patients is still lacking because of a limited literature. According to the recommendations by the International Society for Peritoneal Dialysis for PD-related infections, organisms such as Serratia, Pseudomonas, Providencia, Citrobacter, and Enterobacter are reported to be important causes of relapse and are more often associated with catheter loss and death (8). Moreover, Gursu et al. suggested treating Citrobacter peritonitis individually by observing the patient’s condition and not hesitating to remove the catheter if the patient’s clinical condition deteriorates (5). In our case of a patient with diabetes, both pathogens were sensitive to levofloxacin, but resistant to all cephalosporins except cefepime. Our patient had an excellent response to levofloxacin without catheter removal, and he had no further peritonitis episodes during 1 year of follow-up.
CONCLUSIONS
C. youngae and P. agglomerans are both rare enteric pathogens that can cause PD peritonitis. Our case is the first reported C. youngae peritonitis, and it was successfully treated with levofloxacin without catheter removal. C. youngae might cause PD peritonitis in diabetic patients and should be considered in the differential diagnosis.
DISCLOSURES
The authors have no financial conflicts of interest to declare.
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