Bacterial and Mycobacterial Pneumonia in Transplant Recipients

Infections in Heart and Lung Transplant Recipients

Infections in heart and lung transplant recipients are complex and heterogeneous. This article reviews the epidemiology, risk factors, specific clinical syndromes, and most frequent opportunistic infections in heart and/or lung transplant recipients that will be encountered in the intensive care unit and will provide a practical approach of empirical management.

Association between Hospital-Acquired Pneumonia and In-Hospital Mortality in Solid Organ Transplant Admissions: An Observational Analysis in Spain, 2004-2021

(1) Background: To analyze the association between hospital-acquired pneumonia (HAP) and in-hospital mortality (IHM) during hospital admission for solid organ transplant in Spain during 2004-2021. (2) Methods: We used national hospital discharge data to select all hospital admissions for kidney, liver, heart, and lung transplants. We stratified the data according to HAP status. To examine time trends, we grouped data into three consecutive 6-year periods (2004-2009; 2010-2015; and 2016-2021). We assessed in-hospital mortality (IHM) in logistic regression analyses and obtained odds ratios (ORs) with their 95% confidence intervals (CIs). (3) Results: We identified a total of 71,827 transplants (45,262, kidney; 18,127, liver; 4734, heart; and 4598, lung). Two thirds of the patients were men. Overall, the rate of HAP during admission was 2.6% and decreased from 3.0% during 2004-2009 to 2.4% during 2016-2021. The highest rate of HAP corresponded to lung transplant (9.4%), whereas we found the lowest rate for kidney transplant (1.1%). Rates of HAP for liver and heart transplants were 3.8% and 6.3%, respectively. IHM was significantly lower during 2016-2021 compared to 2004-2009 for all types of transplants (ORs (CIs) = 0.65 (0.53-0.79) for kidney; 0.73 (0.63-0.84) for liver; 0.72 (0.59-0.87) for heart; and 0.39 (0.31-0.47) for lung). HAP was associated with IHM for all types of transplants (ORs (CIs) = 4.47 (2.85-9.08) for kidney; 2.96 (2.34-3.75) for liver; 1.86 (1.34-2.57) for heart; and 2.97 (2.24-3.94) for lung). (4) Conclusions: Rates of HAP during admission for solid organ transplant differ depending on the type of transplant. Although IHM during admission for solid organ transplant has decreased over time in our country, HAP persists and is associated with a higher IHM after accounting for potential confounding variables.

Pulmonary Complications in Renal Transplant Recipients

Background Kidney transplantation recipients are at an increased risk of lung complications due to infectious or non-infectious reasons. We aimed to determine the lung complications after transplantation and what we could do to prevent the complications during the follow-up, retrospectively. Material and Methods The 296 patients who underwent kidney transplantation surgery in our centre between the years 1999 to 2006 were included in the study. Results 75% of the patients were male (n: 222). 77% of the patients (n: 228) had a living-related donor. The mean hospitalisation duration in the post-transplantation period was 13.3±9.07 days. During the follow-up, 37.2% of the patients (n: 110) had rejection, and pulse steroid treatments were given to the 74.5% of these patients. In our study, the lung complication development ratio was 16.2%, and 84% of these complications were due to infections. A specific aetiology was not identified in 63.5% of patients. The patients with a living-related donor had more lung complications due to infection (p

The utility of bronchoscopy in immunocompromised patients: a review

Bronchoscopy is an important tool for the diagnosis of pulmonary disorders in immunocompromised patients. The addition of biopsies to bronchoalveolar lavage improves the diagnostic yield of non-infectious etiologies, although the underlying etiology of the immunocompromised state must be considered and may be influential. Certain unknowns remain, including timing of bronchoscopy and its impact on medical management and mortality. The ongoing role of non-invasive testing for infectious complications prior to bronchoscopy also remains to be defined. This review addresses the role of bronchoscopy in immunocompromised states related to underlying hematologic malignancies, prescription drug use or chemotherapy, and other disorders that predispose patients to infectious or non-infectious pulmonary diseases.

Infections in Heart and Lung Transplant Recipients

Infections in heart and lung transplant recipients are complex and heterogeneous. This article reviews the epidemiology, risk factors, specific clinical syndromes, and most frequent opportunistic infections in heart and/or lung transplant recipients that will be encountered in the intensive care unit and will provide a practical approach of empirical management.

Severe infections in critically ill solid organ transplant recipients

BACKGROUND

Severe infections are among the most common causes of death in immunocompromised patients admitted to the intensive care unit. The epidemiology, diagnosis and treatment of these infections has evolved in the last decade.

AIMS

We aim to provide a comprehensive review of these severe infections in this population.

SOURCES

Review of the literature pertaining to severe infections in critically ill solid organ transplant recipients. PubMed and Embase databases were searched for documents published since database inception until November 2017.

CONTENT

The epidemiology of severe infections has changed in the immunocompromised patients. This population is presenting to the intensive care unit with specific transplantation procedure-related infections, device-associated infections, a multitude of opportunistic viral infections, an increasing number of nosocomial infections and bacterial diseases with a more limited therapeutic armamentarium. Both molecular diagnostics and imaging techniques have had substantial progress in the last decade, which will, we hope, translate into faster and more precise diagnoses, as well as more optimal empirical treatment de-escalation.

IMPLICATIONS

The key clinical elements to improve the outcome of critically ill solid organ transplant recipients depend on the knowledge of geographic epidemiology, specific surgical procedures, net state of immunosuppression, hospital microbial ecology, aggressive diagnostic strategy and search for source control, rapid initiation of antimicrobials and minimization of iatrogenic immunosuppression.

Utility of Mean Platelet Volume to Diagnose Pneumonia in Patients With Solid-Organ Transplant

OBJECTIVES

Despite improved success with solid-organ transplant procedures, recipients remain at risk for infections, including pneumonia, due to their immunosuppressive regimens. In solid-organ transplant patients, clinical findings of pneumonia can be nonspecific, and diagnosis of pneumonia may be difficult as several conditions (drug lung, hypervolemia, infections, hemorrhage) can led to pulmonary infiltrates, mimicking pneumonia in these patients. The role of mean platelet volume, a predictor of inflammatory disease, with elevated values inversely correlated with inflammatory problems, in the diagnosis of pneumonia has not yet been investigated in solid-organ transplant patients. Here, we retrospectively investigated mean platelet volume in diagnosis of pneumonia in transplant patients.

MATERIALS AND METHODS

Medical records of solid-organ transplant patients from 2011 to 2016 were reviewed for demographic, clinical, radiographic, laboratory, and microbiology data. Transplant type, immunosuppressive drugs, and clinical outcomes were noted. Pneumonia diagnosis was based on clinical respiratory symptoms and signs, imaging findings, positive microbiological tests, pathologic findings, laboratory findings, or effective clinical treatment trials.

RESULTS

Our study included 70 patients (47 male/23 female; mean age of 46 ± 14 years), comprising 26 liver and 44 renal transplant recipients. Pneumonia was diagnosed radiologically in 30 patients (42.9%), with procalcitonin positive in 11 patients (36.7%), C-reactive protein elevated in 29 patients (96.7%), and leukocytes increased in 6 patients (20%). When laboratory measurements were compared with mean platelet volume, mean platelet volume values were significantly lower in patients with pneumonia who had elevated procalcitonin levels (P = .038).

CONCLUSIONS

We found that mean platelet volume for diagnosis of pneumonia in solid-organ transplant patients was not a promising tool. Considering the difficulties in caring for transplant patients with pulmonary infiltrates, clinical decisions should be based on clinical, laboratory, microbiological, and radiologic findings.

Lower Respiratory Tract Infections

This review will focus on the infectious etiologies and more common noninfectious causes of lower respiratory tract syndromes among major immunosuppressed populations. The changing epidemiology of infections in the era of highly active antiretroviral therapy (HAART) in the case of HIV-positive patients and the impacts of both newer immune-suppressant therapies and anti-infective prophylaxis for other immunocompromised hosts will be discussed, with emphasis on diagnostic approaches and practice algorithms.

Prevalence, Cause, and Treatment of Respiratory Insufficiency After Orthotopic Heart Transplant

OBJECTIVES

Heart transplant is the best treatment for end-stage heart failure. Respiratory insufficiency after heart transplant is a potentially serious complication. Pulmonary complications, pulmonary hypertension, allograft failure or rejection, and structural heart defects in the donor heart are among the causes of hypoxemia after transplant. In this study, we evaluated the prevalence of hypoxemia and respiratory insufficiency in patients with orthotopic heart transplant during the early postoperative period.

MATERIALS AND METHODS

We retrospectively evaluated the medical records of 45 patients who had received orthotopic heart transplant at our center. Clinical and demographic variables and laboratory data were noted. Oxygen saturation values from patients in the first week and the first month after transplant were analyzed. We also documented the cause of respiratory insufficiency and the type of treatment.

RESULTS

Mean age was 35.3 ± 15.3 years (range, 12-61 y), with males comprising 32 of 45 patients (71.1%). Two patients had mild chronic obstructive pulmonary disease and 1 had asthma. Twenty-five patients (55.6%) had a history of smoking. Respiratory insufficiency was noted in 9 patients (20%) during the first postoperative week. Regarding cause, 5 of these patients (11.1%) had pleural effusion, 2 (4.4%) had atelectasis, 1 (2.2%) had pneumonia, and 1 (2.2%) had acute renal failure. Therapies administered to patients with respiratory insufficiency were as follows: 5 patients had oxygen therapy with nasal canula/mask, 3 patients had continuous positive airway pressure, and 1 patient had mechanical ventilation. One month after transplant, 2 patients (4.4%) had respiratory insufficiency 1 (2.2%) due to pleural effusion and 1 (2.2%) due to atelectasis.

CONCLUSIONS

Respiratory insufficiency is a common complication in the first week after orthotopic heart transplant. Identification of the underlying cause is an important indicator for therapy. With appropriate care, respiratory insufficiency can be treated successfully.

Diagnostic bronchoscopy in solid-organ and hematopoietic stem cell transplantation

Fiberoptic bronchoscopy is a valuable diagnostic tool in solid-organ and hematopoietic stem cell transplant recipients presenting with a range of pulmonary complications. This article provides a comprehensive overview of the utility and potential adverse effects of diagnostic bronchoscopy for transplant recipients. Recommendations are offered on the selection of patients, the timing of bronchoscopy, and the samples to be obtained across the spectrum of suspected pulmonary complications of transplantation. Based on review of the literature, the authors recommend early diagnostic bronchoscopy over empiric treatment in transplant recipients with evidence of certain acute, subacute, or chronic pulmonary processes. This approach may be most critical when an underlying infectious etiology is suspected. In the absence of prompt diagnostic information on which to base effective treatment, the risks associated with empiric antimicrobial therapy, including medication side effects and the development of antibiotic resistance, compound the potential harm of delaying targeted management.

Pulmonary infections in transplant recipients

PURPOSE OF REVIEW

Hematopoietic stem cell as well as solid-organ transplantation is being carried out with increasing frequency throughout the world. Lower respiratory tract infections (LRTIs) remain a common life-threatening complication faced by the transplant recipients. The purpose of this review is to provide up-to-date information on pulmonary infections among the transplant recipients, especially emphasizing the endemicity of microorganisms, epidemiology, work-up of infections, and principles of their management.

RECENT FINDINGS

A lower respiratory tract infection such as pneumonia is the most frequent of all the infections and is associated with high morbidity and mortality. Factors increasing the risk of pulmonary infections include surgical techniques, immune status, chemoradiotherapy, alloimmune mechanisms between the host and the graft, and the environment. A high degree of suspicion, computed tomography (CT) scan of the chest, and flexible bronchoscopy are required in most to establish the diagnosis.

SUMMARY

Proper management of LRTI in transplant recipients requires a high degree of suspicion, thorough knowledge of the epidemiology and endemicity of the suspected organisms, CT scan of the chest, and expertise at bronchoscopy. Utmost teamwork among transplant physicians, infectious disease specialist, and bronchoscopist is essential.

Impaired pulmonary immunity post-bone marrow transplant

Infectious complications are a serious cause of morbidity and mortality following hematopoietic stem cell transplantation (HSCT), and the lung is a particular target organ post-transplant. Our laboratory has used a murine bone marrow transplant model to study alterations in immunity that occur as a result of transplantation. Our studies focus on immune responses that occur following immune cell reconstitution in the absence of immunosuppressive drug therapy or graft-versus-host disease. We have found that impaired clearance of both bacterial and viral pulmonary infections is related to specific alterations in immune cell function and cytokine production. Our data offer insight into mechanisms that contribute to opportunistic infections in HSCT recipients.

Pulmonary nocardiosis after lung transplantation: CT findings in 7 patients and review of the literature

OBJECTIVE

The purpose of this study is to review reported radiographic clues to the diagnosis of pulmonary nocardiosis, as well as to describe and illustrate the high-resolution computed tomography findings of 7 patients with pulmonary nocardiosis after lung transplantation.

CONCLUSIONS

Computed tomography findings of pulmonary nocardiosis after lung transplantation consist predominantly of nodules and cavitary lesions without any significant zonal or anatomic distribution. The diagnosis of pulmonary nocardiosis requires a high index of suspicion, as presenting symptoms are nonspecific, initial visualization is often not possible with routine stains, and identification requires prolonged cultures.

Surgical therapies for pulmonary arterial hypertension

Surgical therapies for the treatment of pulmonary arterial hypertension typically are reserved for patients who are deemed to be refractory to medical therapy and have evidence of progressive right-sided heart failure. Atrial septostomy, a primarily palliative procedure, may stave off hemodynamic collapse from right-sided heart failure long enough to permit a more definitive surgical treatment such as lung or combined heart-lung transplantation. This article discusses indications for and results of atrial septostomy and lung and heart-lung transplantation in patients who have pulmonary arterial hypertension.