Rhodococcus equi peritonitis in continuous ambulatory peritoneal dialysis: a first in Australia

Pleural empyema with endobronchial mass due to Rhodococcus equi infection after renal transplantation: A case report and review of literature

BACKGROUND

Kidney transplantation is the best option for patients with end-stage renal disease. However, the need for lifelong immunosuppression results in renal transplant recipients being susceptible to various infections. Rhodococcus equi (R. equi) is a rare opportunistic pathogen in humans, and there are limited reports of infection with R. equi in post-renal transplant recipients and no uniform standard of treatment. This article reports on the diagnosis and treatment of a renal transplant recipient infected with R. equi 21 mo postoperatively and summarizes the characteristics of infection with R. equi after renal transplantation, along with a detailed review of the literature.

CASE SUMMARY

Here, we present the case of a 25-year-old man who was infected with R. equi 21 mo after renal transplantation. Although the clinical features at the time of presentation were not specific, chest computed tomography (CT) showed a large volume of pus in the right thoracic cavity and right middle lung atelectasis, and fiberoptic bronchoscopy showed an endobronchial mass in the right middle and lower lobe orifices. Bacterial culture and metagenomic next-generation sequencing sequencing of the pus were suggestive of R. equi infection. The immunosuppressive drugs were immediately suspended and intravenous vancomycin and azithromycin were administered, along with adequate drainage of the abscess. The endobronchial mass was then resected. After the patient's clinical symptoms and chest CT presentation resolved, he was switched to intravenous ciprofloxacin and azithromycin, followed by oral ciprofloxacin and azithromycin. The patient was re-hospitalized 2 wk after discharge for recurrence of R. equi infection. He recovered after another round of adequate abscess drainage and intravenous ciprofloxacin and azithromycin.

CONCLUSION

Infection with R. equi in renal transplant recipients is rare and complex, and the clinical presentation lacks specificity. Elaborate antibiotic therapy is required, and adequate abscess drainage and surgical excision are necessary. Given the recurrent nature of R. equi, patients need to be followed-up closely.

A case of peritoneal dialysis-associated peritonitis caused by Rhodococcus kroppenstedtii

BACKGROUND

Rhodococcus kroppenstedtii is an aerobic, gram-positive bacterium firstly identified in the environment, which has not been reported in human-related infection. Herein, we reported the first case of peritoneal dialysis (PD)-associated peritonitis caused by R. kroppenstedtii which was identified by whole genome sequencing.

CASE PRESENTATION

A 69-year-old man was admitted to hospital with abdominal pain and fever. Over the last 2 years, he had been undergoing continuous ambulatory peritoneal dialysis (CAPD) due to end-stage renal disease. Clinical symptom and sign in combination with laboratory examinations supported the clinical diagnosis of PD-associated peritonitis. Thus, ceftizoxime and teicoplanin were empirically used after PD effluent was collected for bacterial culture. A gram-positive bacterium was found from the PD effluent culture, which could not be identified by either Vitek 2 Compact ANC card or matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The strain was finally confirmed to be R. kroppenstedtii by whole genome sequencing (WGS) through the average nucleotide identity (ANI) analysis. With a continuous treatment with teicoplanin and imipenem for 15 days and intraperitoneal catheter removed, the infection symptom was improved evidenced by a normal body temperature, also with white blood cell count (WBC), procalcitonin (PCT) and C-reactive protein (CRP) dropped to normal levels. Peritoneal dialysis effluent culture showed a negative result. Then, hemodialysis and arteriovenous fistula angioplasty were performed, but the patient developed a progressive blood pressure loss, accompanied by multiple organ disorder, and died on Feb 25, 2020.

CONCLUSIONS

To the best of our knowledge, this is the first time to report a peritoneal dialysis-associated peritonitis caused by R. kroppenstedtii which was identified by average nucleotide identity analysis based on WGS.