# Nocardia Infection Presented as Intramuscular Abscess in a Kidney Transplant Recipient: Case Report and Literature Review

## TL;DR

A kidney transplant recipient developed a rare Nocardia muscle abscess, successfully treated with antibiotics after drug resistance was identified.

## Contribution

This case report highlights a rare presentation of Nocardia pseudobrasiliensis as an intramuscular abscess in a transplant recipient.

## Key findings

- Nocardia pseudobrasiliensis was isolated from an intramuscular abscess in a kidney transplant recipient.
- The isolate was resistant to imipenem but susceptible to ciprofloxacin, azithromycin, and TMP-SMX.
- Long-term treatment with ciprofloxacin and azithromycin led to a good clinical response without recurrence.

## Abstract

Nocardia is a gram-positive bacterium capable of causing both local and systemic infections, typically in immunocompromised patients. The most common clinical presentation is pulmonary infection. Muscle abscess due to Nocardia infection without disseminated nocardiosis is rare.

In this report, we describe the case of a 67-year-old male kidney transplant recipient who developed a swelling of the right biceps muscle. CT imaging showed an intramuscular abscess, which was subsequently surgically drained. The drained fluid grew Nocardia pseudobrasiliensis, which was resistant to imipenem but susceptible to trimethoprim/sulfamethoxazole (TMP-SMX), ciprofloxacin and linezolid. The patient was initially treated with TMP-SMX and ciprofloxacin. Treatment was changed to 6 months of ciprofloxacin and azithromycin due to intolerance to TMP-SMX which resulted in a good clinical response and no recurrence for 3 years. We also review all previously reported N. pseudobrasiliensis infections and cases of nocardiosis presenting as intramuscular infections.

Given its prevalence amongst immunocompromised patients, Nocardiosis requires consideration in the differential diagnosis for the cause of atypical infections in transplant recipients. The antimicrobial susceptibilities of Nocardia are variable depending on species. Of key note, carbapenem resistance has been recently described in N. pseudobrasiliensis. This development should be considered when initiating antimicrobial therapy to ensure good patient response to treatment.