Pneumocystis jirovecii in solid organ transplant recipients: updates in epidemiology, diagnosis, treatment, and prevention

PURPOSE OF REVIEW

This review highlights the epidemiology of Pneumocystis jirovecii pneumonia in solid organ transplant recipients, advancements in the diagnostic landscape, and updates in treatment and prevention.

RECENT FINDINGS

The increasing use of immune-depleting agents in the context of solid organ transplantation has given rise to P. jirovecii pneumonia in this population. The use of prophylaxis has dramatically reduced risk of infection; however, late-onset infections occur after cessation of prophylaxis and in the setting of lymphopenia, advancing patient age, acute allograft rejection, and cytomegalovirus infection. Diagnosis requires respiratory specimens, with PCR detection of Pneumocystis replacing traditional staining methods. Quantitative PCR may be a useful adjunct to differentiate between infection and colonization. Metagenomic next-generation sequencing is gaining attention as a noninvasive diagnostic tool. Trimethoprim-sulfamethoxazole remains the drug of choice for treatment and prevention of Pneumocystis pneumonia. Novel antifungal agents are under investigation.

SUMMARY

P. jirovecii is a fungal opportunistic pathogen that remains a cause of significant morbidity and mortality in solid organ transplant recipients. Early detection and timely treatment remain the pillars of management.

A cluster of six respiratory cultures positive for Mycobacterium xenopi -Clinical characteristics and genomic characterization

Mycobacterium xenopi is a slow growing non-tuberculous mycobacterium (NTM) isolated from water systems and has been associated with pseudo-outbreaks and pulmonary infections in humans. We observed a cluster of six respiratory cultures positive for M. xenopi within a six-month period at our institution, approximately double our normal isolation rate of this organism. Only three of the six cases met clinical, radiographic, and microbiologic criteria for NTM infection. An investigation led by our hospital's Healthcare Epidemiology and Infection Program found no epidemiologic link between the six patients. Three isolates underwent whole-genome sequencing (WGS) and phylogenetic analysis confirmed they were non-clonal. In vitro susceptibility data found the isolates were sensitive to macrolides, moxifloxacin, and rifabutin. Our findings suggest that isolation of M. xenopi from pulmonary specimens may be increasing, further defines the genomic population structure of this potentially emerging infection, and establishes WGS as a useful tool for outbreak investigation strain typing.

Use of Novel Strategies to Develop Guidelines for Management of Pyogenic Osteomyelitis in Adults: A WikiGuidelines Group Consensus Statement

IMPORTANCE

Traditional approaches to practice guidelines frequently result in dissociation between strength of recommendation and quality of evidence.

OBJECTIVE

To construct a clinical guideline for pyogenic osteomyelitis management, with a new standard of evidence to resolve the gap between strength of recommendation and quality of evidence, through the use of a novel open access approach utilizing social media tools.

EVIDENCE REVIEW

This consensus statement and systematic review study used a novel approach from the WikiGuidelines Group, an open access collaborative research project, to construct clinical guidelines for pyogenic osteomyelitis. In June 2021 and February 2022, authors recruited via social media conducted multiple PubMed literature searches, including all years and languages, regarding osteomyelitis management; criteria for article quality and inclusion were specified in the group's charter. The GRADE system for evaluating evidence was not used based on previously published concerns regarding the potential dissociation between strength of recommendation and quality of evidence. Instead, the charter required that clear recommendations be made only when reproducible, prospective, controlled studies provided hypothesis-confirming evidence. In the absence of such data, clinical reviews were drafted to discuss pros and cons of care choices. Both clear recommendations and clinical reviews were planned with the intention to be regularly updated as new data become available.

FINDINGS

Sixty-three participants with diverse expertise from 8 countries developed the group's charter and its first guideline on pyogenic osteomyelitis. These participants included both nonacademic and academic physicians and pharmacists specializing in general internal medicine or hospital medicine, infectious diseases, orthopedic surgery, pharmacology, and medical microbiology. Of the 7 questions addressed in the guideline, 2 clear recommendations were offered for the use of oral antibiotic therapy and the duration of therapy. In addition, 5 clinical reviews were authored addressing diagnosis, approaches to osteomyelitis underlying a pressure ulcer, timing for the administration of empirical therapy, specific antimicrobial options (including empirical regimens, use of antimicrobials targeting resistant pathogens, the role of bone penetration, and the use of rifampin as adjunctive therapy), and the role of biomarkers and imaging to assess responses to therapy.

CONCLUSIONS AND RELEVANCE

The WikiGuidelines approach offers a novel methodology for clinical guideline development that precludes recommendations based on low-quality data or opinion. The primary limitation is the need for more rigorous clinical investigations, enabling additional clear recommendations for clinical questions currently unresolved by high-quality data.

Invasive pulmonary aspergillosis after treatment with tocilizumab in a patient with COVID-19 ARDS: a case report

Tocilizumab, an interleukin-6 receptor antagonist, has been used to treat critically ill patients with coronavirus disease-2019. We present the case of a previously immunocompetent man with coronavirus disease-2019 who developed invasive pulmonary aspergillosis after treatment with tocilizumab, illustrating the importance of considering opportunistic infections when providing immune modulating therapy.

1164. Epidemiology of Cryptococcal Infections in Non-HIV Patients: A 20-year Single Center Experience

Background

Cryptococcus has a worldwide distribution, with C. neoformans and C. gattii being two of the most common species causing disease. Despite advances in therapy, disseminated infection often results in significant morbidity and mortality.

Methods

We conducted a single center retrospective cohort study over a twenty-year period spanning from January 2000 through May 2020 to determine epidemiology and outcomes of non-HIV-associated cryptococcosis at Northwestern Memorial Hospital. Cases were identified by positive culture data or positive cryptococcal antigen in the serum or cerebrospinal fluid (CSF). Epidemiology of risk factors, morbidity, and mortality was evaluated.

Results

81 cases were identified of which, 67 had Cryptococcus spp isolated from culture and the remaining patients diagnosed by cryptococcal antigen and/or histopathology. The cohort was primarily Caucasian (56.8%, n=46) and male gender (67.9%, n=55), with a median age of 59.5 (IQR: 52.75-66.25) years old. Common predisposing conditions were diabetes (37%, n=30), chronic kidney disease (34.6%, n=28), and liver disease (28.4%, n=23). Solid organ transplant recipients and use of immunosuppression accounted for, respectively, 32.1% (n=26) and 29.6% (n=24) of the cohort. Sites of infection include lung (65.4%. n=53), central nervous system (33.3%, n=27), blood (30.9%, n=25), peritoneum (6.2%, n=5), musculoskeletal (2.5%, n=2), and prostate (1.2%, n=1). Mean opening pressure on lumbar puncture was 25.3 mmHg (range: 9 -52 mmHg). In hospital mortality at time of diagnosis was 27.2% (n=22), and mortality at 12 months post diagnosis was 51.9% (n=42).

Conclusion

At our center, those with cryptococcosis commonly had risk factors such as immunosuppression either secondary to solid organ transplant or otherwise. Morbidity and mortality remain high.

Disclosures

Sudhir Penugonda, MD, MPH, AbbVie, Inc. (Employee, Other Financial or Material Support, ownership and/or investment interests) Michael Angarone, DO, Abbvie (Other Financial or Material Support, Data Safety Monitoring Board)Allergan (Speaker’s Bureau)

Diagnosis and management of diarrhea in solid-organ transplant recipients: Guidelines from the American Society of Transplantation Infectious Diseases Community of Practice

These guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of diarrhea in the pre- and post-transplant period. Diarrhea in an organ transplant recipient may result in significant morbidity including dehydration, increased toxicity of medications, and rejection. Transplant recipients are affected by a wide range of etiologies of diarrhea with the most common causes being Clostridioides (formerly Clostridium) difficile infection, cytomegalovirus, and norovirus. Other bacterial, viral, and parasitic causes can result in diarrhea but are far less common. Further, noninfectious causes including medication toxicity, inflammatory bowel disease, post-transplant lymphoproliferative disease, and malignancy can also result in diarrhea in the transplant population. Management of diarrhea in this population is directed at the cause of the diarrhea, instituting therapy where appropriate and maintaining proper hydration. Identification of the cause to the diarrhea needs to be timely and focused.

1129. Targeted Voriconazole Prophylaxis in Heart Transplantation Recipients

Background

The use of antifungal prophylaxis, targeted or universal, remains controversial and unstudied. The goal of this study is to determine the role of targeted voriconazole prophylaxis (VORI) in prevention of invasive fungal infections (IFI) after heart transplantation (HT).

Methods

We conducted a single-center, prospective, observational cohort study of 276 HT recipients from June 2005 to April 2017 to characterize the incidence and outcome of IFI following targeted VORI. Starting in June 2013, HT recipients with thymoglobulin (ATG) treatment received VORI for 3 months. Probable/proven IFI were defined by EORTC/MSG criteria. Descriptive frequencies and univariate analyses were performed.

Results

Mean duration of follow-up post-HT was 1,165 days (0–3,152 days). 149 (54%) and 70 (25%) received basiliximab and thymoglobulin induction, respectively. Thirty-one (11%) received VORI, following use of ATG in the setting of induction (68%) or rejection (32%). VORI was started at median of 6 days (0–1,008 days) post-HT for a mean duration of 97 days (5–251 days). Overall, 23 IFIs occurred in 23 recipients (8%) at mean 283 days post-HT (range 2–1,579 days), including seven Aspergillus (one occurring after VORI completion), seven invasive Candida (five with candidemia), two Rhizopus, one Cunninghamella, two histoplasma, two blastomyces, one Cryptococcus, and one multifocal cutaneous Alternaria.

Conclusion

Targeted VORI resulted in reduced incidences of both early and overall IFI after HT although this did not reach statistical significance. Since instituting this strategy, we have observed a single case of aspergillosis following VORI discontinuation. Overall and 1-year mortality were not impacted. The use of antifungal prophylaxis following HT requires continued investigation both to determine efficacy and toxicity in this patient population.

Disclosures

All authors: No reported disclosures.

Diarrhea in solid organ transplant recipients

PURPOSE OF REVIEW

Diarrhea is a common complaint in the solid organ transplant recipient. Unlike the immune-competent patient, diarrhea in an organ transplant recipient may result in dehydration, increased toxicity of medications, and rejection. There is a wide range of causes for diarrhea in transplant recipients, but the most common causes are Clostridium difficile infection, cytomegalovirus, and norovirus. This review will focus on new epidemiology data as to the cause of diarrhea in the transplant population.

RECENT FINDINGS

Recent data have identified C. difficile, cytomegalovirus, and norovirus as important causes of diarrhea in this population, and management should be focused on these causes. Newer diagnostic platforms (such as PCR) are being evaluated, which may help in identification of the cause of diarrhea.

SUMMARY

New epidemiologic data and new testing techniques offer an opportunity for research into better testing strategies for transplant patients with diarrhea. These newer testing strategies may offer better insight into the cause of diarrhea and more appropriate treatment for this illness.

Fungal infections in cancer patients

Invasive fungal infections (IFI) have become a leading cause of morbidity and mortality in cancer patients. Infections with these organisms are often difficult to diagnose and treat. Appropriate and timely diagnosis requires a high index of suspicion and invasive procedures, including biopsy, to confirm the diagnosis. Treatment may be difficult, secondary to variable susceptibility and difficulty with exact and specific characterization of the fungal pathogen. The pathogens that are seen range from yeasts to invasive molds. Fortunately newer, noninvasive diagnostic techniques are available to aid in the diagnosis and treatments have become better tolerated and more efficacious.

Prevention and treatment of cancer-related infections

Patients with cancer are at increased risk for developing infectious complications during the course of their disease and treatment. The following sections of the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Prevention and Treatment of Cancer-Related Infections provide an overview of the risk factors for infectious complications, recommendations for infectious risk categorization, and strategies for prevention of infections in high-risk patient populations with cancer. Individualized risk evaluation for infections and incorporation of preventative measures are essential components of the overall spectrum of cancer care, and may contribute to optimizing treatment outcomes for patients.

Epidemiology and prevention of viral infections in patients with hematologic malignancies

Viral infections are some of the most frequent complications in patients with hematologic malignancies are viral infections. Infections caused by cytomegalovirus, herpes simplex virus, varicella zoster virus, hepatitis B virus and influenza virus are associated with high morbidity and mortality in this vulnerable population. Fortunately, a growing number of antiviral medications and vaccines are allowing for more effective prophylaxis against these pathogens. This article reviews the epidemiology and prophylactic strategies available for these opportunistic viral pathogens.

Prevention and early treatment of opportunistic viral infections in patients with leukemia and allogeneic stem cell transplantation recipients

A leading complication of leukemia therapy and stem cell transplantation is opportunistic viral infections. Infections caused by cytomegalovirus, herpes simplex, varicella-zoster, Epstein-Barr, and the community respiratory viruses are associated with significant morbidity and mortality in this highly immunosuppressed population. Fortunately, a growing armamentarium is allowing more effective prophylaxis of these pathogens. This article reviews the epidemiology and prophylactic strategies available for these common opportunistic viral pathogens.