Disseminated Rhodococcus equi infection in a kidney transplant patient without initial pulmonary involvement

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.

Rhodococcus equi: Another great masquerader

Rhodococcosis is a serious infection specially affecting immunocompromised populations. We report a case of disseminated infection by Rhodococcus equi in a renal transplant patient, that was initially diagnosed as histoplasmosis, highlighting the potential for confusion between rhodococcosis and other infections. Clinicians and pathologists should correlate histopathology findings with the clinical and microbiological data.

Diagnosis and management of pulmonary infection due to Rhodococcus equi

BACKGROUND

Rhodococcus equi is a recognized cause of disease in humans, especially in individuals who are immunocompromised. Because diphtheroids are regarded as part of normal respiratory flora, the importance of R. equi as a pulmonary pathogen may not be fully appreciated and its prevalence may be underestimated. Most treatment recommendations for R. equi infection were established before antiretroviral drugs became available for human immunodeficiency virus/AIDS therapy, and therapeutic strategies may need to be updated.

OBJECTIVES

To review the role of R. equi as a cause of pulmonary infection; to highlight its importance for clinicians and microbiologists; and to challenge current approaches to treatment, whether in immunodeficient or immunocompetent individuals.

SOURCES

A PubMed search using combinations of the following terms: 'Rhodococcus (automatically including Corynebacterium) equi' AND 'pneumonia' OR 'pulmonary' infection, then cross-checking references in the resulting cases, case series and reviews.

CONTENT

We provide a review that details the challenges in the diagnosis, microbiology and pathogenesis of pulmonary infection caused by R. equi and the options for treatment.

IMPLICATIONS

Ten to 14 days of treatment may be effective for pneumonia due to R. equi. Our review suggests that longer courses of therapy are needed for cavitary lesions and lung masses. However, recommendations for excessively prolonged treatment of all pulmonary infections arose during a time when many cases occurred in individuals with AIDS and before effective antiretroviral therapy was available. We suggest that the rationale for prolonged therapy with multiple antibiotics needs to be re-evaluated.

Rhodococcus equi Sepsis in a Renal Transplant Recipient: A Case Study

Rhodococcus equi is an unusual cause of infection in humans, but has emerged as an opportunistic pathogen among immunocompromised patients. Primary pulmonary involvement is the most common clinical presentation, although the spectrum of disease is broad. Diagnosing R. equi infections remains challenging, both from clinical and microbiological view, and no standard treatment has been established. In this report, we present a detailed case of a 57-year-old male renal transplant recipient who developed R. equi bacteremia with a concomitant Pneumocystis jirovecii pneumonia. We describe the clinical features of R. equi infections, highlight the importance of an early diagnosis, and briefly review treatment options for this rare infection.

Novel fastidious, partially acid-fast, anaerobic Gram-positive bacillus associated with abscess formation and recovered from multiple medical centers

We report a novel anaerobe causing abscess in four patients at three hospitals. In the clinical specimen, bacilli were branching, Gram positive, and acid fast. The organism grew slowly and was not identified by 16S rRNA sequencing. Our findings support the description of a new genus and species of the suborder Corynebacterineae.

Persistent Rhodococcus equi infection in a renal transplant patient: case report and review of the literature

Rhodococcus equi is a pathogen that mainly causes infection in immunocompromised hosts. We report a case of relapsing R. equi pulmonary infection in a 57-year-old male renal transplant recipient who was treated with 12 months of antibiotics, adjunctive surgery, and a reduction in his immunosuppression. He suffered from relapsing disease, treatment-related complications, and ultimately died of Pneumocystis pneumonia. Case reports in the literature portray a good cure rate for transplant-related R. equi infections, with shorter durations of antibiotics. The case illustrates the difficulties in the management of R. equi infections. Forty cases from the literature were reviewed and compared in terms of epidemiology, location of infection, transplant type, immunosuppression used, treatment used, outcomes, and possible exposures.

Rhodococcal lung abscess in a renal transplant recipient

Background:

Rhodococcus species are relatively rare human pathogens, but are being increasingly recognized as causes of infection especially in immunosuppressed patients.

Case Report:

We present a case of Rhodococcus lung abscess in a patient 10 months post-cadaveric renal transplant, successfully treated with a combination of antibiotics. She required a prolonged course of oral antibiotics for 6 months. She did not require surgical intervention. Chest X-rays and CT thorax showed complete resolution of the initial lesion. We also review the medical literature related to Rhodococcus infection in patients with renal transplantation. Rhodococcus infection should be considered as in the differential diagnosis of immunosuppressed patients who present with lung abscess/mass.

Conclusions:

A literature review indicates this is a potentially fatal condition with disseminated sepsis/abscesses.

[Infections in organ transplantations]

Infections play a crucial role in organ transplantations as possible complications. Viruses, bacteria, fungi and parasites are potential agents. The relevance of individual diseases depends on the organ transplanted. Morphology of the inflammatory reaction is given by the agent involved, but often several reactions can be caused by the same agent and different agents can also lead to the same reaction. Histology therefore provides concrete identification of the causal agent only in some cases, such that additional microbiological diagnostics are necessary. Results from these investigations should be transferred to the pathologist to distinguish between infection-associated changes and transplant rejection.

Brief Tale of a Bacteraemia by Rhodococcus equi, With Concomitant Lung Mass: What Came First, the Chicken or The Egg?

Rhodococcus equi is an uncommon Gram positive, variably acid-fast pathogen, that appears as hard to treat mostly owing to the establishment of intracellular niches. Lack of interpretive criteria for susceptibility testing may lead to under-reporting or overestimation of resistances, whereas knowledge about this pathogen’s clinical impact may be affected by erroneous phenotype-based characterization at a genus and species level.

We present the case of a bacteraemia with a concomitant lung mass in a lymphoma patient, that further highlights the emergence of rhodococcal diseases as a matter for concern in the fields of infectious diseases and haematology.