Evidence Hub

A case of Nocardia asiatica pneumonia: Relapse caused by trimethoprim-sulfamethoxazole treatment nonadherence

Zuo H, Zhao F, Wu C, Gu J, Dong N, Zhang X, Ying Y, Guo Y et al.

IDCases, 2026

Abstract

Nonadherence to trimethoprim-sulfamethoxazole (TMP-SMX) is a known risk factor for nocardiosis treatment failure, often due to adverse effects. However, reports linking relapse to treatment interruption caused by poor adherence are scarce. A 70-year-old male with chronic bronchitis presented with persistent fever, cough, and sputum. Nocardia asiatica was identified. Initial improvement followed a 28-day TMP-SMX course, but the patient discontinued therapy. Multiple readmissions over three years resulted from relapses due to poor adherence. Whole-genome sequencing of isolates from the first and third episodes revealed 99.9% genetic similarity, confirming relapse from the original strain. Only after completing a full six-month TMP-SMX course did the patient achieve sustained remission with no recurrence for five years. This case provides molecular evidence supporting that premature TMP-SMX discontinuation contributed to relapse, emphasizing that adherence is as critical as accurate diagnosis for cure.

How strong is the evidence?

Evidence Hub reads this as a case report, done in people. Its evidence level is 5 of 5 (Very low · case / narrative / animal / in vitro / in silico). Case reports, narrative reviews, and animal, cell or computer-model studies give the weakest evidence for human health.

How the five levels of evidence work. The level is assigned automatically from the abstract and can be wrong, so check the paper.

Read the paper

Related studies

Go deeper in Evidence Hub

Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.

Open this study Sign up free