Evaluation of Pulmonary Infections in Solid Organ Transplant Patients: 12 Years of Experience

A Systematic Literature Review to Determine Gaps in Diagnosing Suspected Infection in Solid Organ Transplant Recipients

Background

Improved diagnostic testing (DT) of infections may optimize outcomes for solid organ transplant recipients (SOTR), but a comprehensive analysis is lacking.

Methods

We conducted a systematic literature review across multiple databases, including EMBASE and MEDLINE(R), of studies published between 1 January 2012-11 June 2022, to examine the evidence behind DT in SOTR. Eligibility criteria included the use of conventional diagnostic methods (culture, biomarkers, directed-polymerase chain reaction [PCR]) or advanced molecular diagnostics (broad-range PCR, metagenomics) to diagnose infections in hospitalized SOTR. Bias was assessed using tools such as the Cochrane Handbook and PRISMA 2020.

Results

Of 2362 studies, 72 were eligible and evaluated heterogeneous SOT populations, infections, biospecimens, DT, and outcomes. All studies exhibited bias, mainly in reporting quality. Median study sample size was 102 (range, 11-1307). Culture was the most common DT studied (N = 45 studies, 62.5%), with positive results in a median of 27.7% (range, 0%-88.3%). Biomarkers, PCR, and metagenomics were evaluated in 7, 19, and 3 studies, respectively; only 6 reported sensitivity, specificity, and positive/negative predictive values. Directed-PCR performed well for targeted pathogens, but only 1 study evaluated broad-range PCR. Metagenomics approaches detected numerous organisms but required clinical adjudication, with too few studies (N = 3) to draw conclusions. Turnaround time was shorter for PCR/metagenomics than conventional diagnostic methods (N = 4 studies, 5.6%). Only 6 studies reported the impact of DT on outcomes like antimicrobial use and length of stay.

Conclusions

We identified considerable evidence gaps in infection-related DT among SOT, particularly molecular DT, highlighting the need for further research.

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

Cryptogenic Organizing Pneumonia Complicated With Cutaneous Disseminated Nocardia Infection: A Case Report and Literature Review

Nocardia disease is a rare opportunistic infection that usually occurs in individuals with solid organ transplantation, malignant tumors, human immunodeficiency virus (HIV) infection, or chronic lung disease history. Here, we reported a rare case of cryptogenic organizing pneumonia (COP) combined with disseminated Nocardia infection. A 75-year-old man was admitted to the respiratory department due to weakness and poor appetite for 3 months. The chest CT scan showed dense patchy shadows in the dorsal lower lobe of both lungs. After the transbronchial lung biopsy, the histopathological findings supported the diagnosis of COP. During the period of glucocorticoid reduction (oral methylprednisolone tablets 24 mg one time a day), the patient presented with masses on the back and bilateral upper limbs and intermittent fever for 3 days. After admission, the patient underwent a series of examinations and an ultrasound puncture of the mass. The puncture fluid was caseous necrosis, which was confirmed to be Nocardia infection after bacterial culture, so the diagnosis was disseminated Nocardia infection. After 13 days of admission, the patient developed a headache, accompanied by decreased visual acuity and blurred vision. An imaging (enhanced brain CT) examination revealed intracranial space-occupying lesions. The neurosurgeon was consulted and performed transcranial abscess puncture and drainage, intravenous antibiotics (meropenem, etc.) for 2 months, and trimethoprim/sulfamethoxazole (TMP-SMX) for 6 months. The patient was followed up for 3 years and has remained relapse-free. The mortality rate of disseminated Nocardia infection is as high as 85%, especially when combined with brain abscesses. Therefore, timely diagnosis and correct treatment are crucial for the prevention of fatal consequences. The report of this case can enable more patients to receive early diagnosis and effective treatment, so as to obtain a satisfied prognosis.

Padrões tomográficos de agentes etiológicos da pneumonia durante o primeiro ano após transplante renal

Objetivo

Avaliar os padrões tomográficos relacionados aos agentes etiológicos da pneumonia em pacientes durante o primeiro ano após transplante renal.

Materiais e Métodos

Foram analisados dados de prontuários de 956 pacientes submetidos a transplante renal, no período de 2013 a 2018, em um centro transplantador renal do nordeste do Brasil. Nos pacientes que desenvolveram pneumonia, os agentes etiológicos foram classificados em bactérias piogênicas, micobactérias, fungos, vírus e pneumonia polimicrobiana, enquanto os padrões tomográficos foram classificados em consolidação, broncopneumonia, pneumonia intersticial e nódulos e massas. Para verificar associação estatística entre micro-organismos e padrões tomográficos, foi utilizado o teste exato de Fisher, com p < 0,001.

Resultados

Foram encontrados 101 casos de pneumonia, dos quais 60 (59,4%) tiveram agente etiológico identificado, sendo as bactérias piogênicas as mais frequentes, detectadas em 22 (36,7%) dos casos. Entre os pacientes com agente causal identificado, o padrão tomográfico predominante foi o de nódulos e massas, identificado em 25 (41,7%) casos. Foi observada associação entre bactérias piogênicas e o padrão de consolidação, fungos com nódulos e massas, bem como entre agentes virais e padrão intersticial.

Conclusão

Foi demonstrada associação estatística entre micro-organismos causadores de pneumonia e padrões tomográficos, informação que pode contribuir para o planejamento da terapia de pacientes transplantados renais.

Aetiology and prognostic risk factors of mortality in patients with pneumonia receiving glucocorticoids alone or glucocorticoids and other immunosuppressants: a retrospective cohort study

OBJECTIVES

Long-term use of high-dose glucocorticoids can lead to severe immunosuppression and increased risk of treatment-resistant pneumonia and mortality. We investigated the aetiology and prognostic risk factors of mortality in hospitalised patients who developed pneumonia while receiving glucocorticoid therapy alone or glucocorticoid and other immunosuppressant therapies.

DESIGN

Retrospective cohort study.

SETTING

Six secondary and tertiary academic hospitals in China.

PARTICIPANTS

Patients receiving glucocorticoids who were hospitalised with pneumonia between 1 January 2013 and 31 December 2019.

MAIN OUTCOMES

We analysed the prevalence of comorbidities, microbiology, antibiotic susceptibility patterns, 30-day and 90-day mortality and prognostic risk factors.

RESULTS

CONCLUSIONS: A total of 716 patients were included, with pneumonia pathogens identified in 69.8% of patients. Significant morbidities occurred, including respiratory failure (50.8%), intensive care unit transfer (40.8%) and mechanical ventilation (36%), with a 90-day mortality of 26.0%. Diagnosis of pneumonia occurred within 6 months of glucocorticoid initiation for 69.7% of patients with Cytomegalovirus (CMV) pneumonia and 79.0% of patients with Pneumocystis jirovecii pneumonia (PCP). Pathogens, including Pneumocystis, CMV and multidrug-resistant bacteria, were identified more frequently in patients with persistent lymphocytopenia and high-dose glucocorticoid treatment (≥30 mg/day of prednisolone or equivalent within 30 days before admission). The 90-day mortality was significantly lower for non-CMV viral pneumonias than for PCP (p<0.05), with a similar mortality as CMV pneumonias (24.2% vs 38.1% vs 27.4%, respectively). Cox regression analysis indicated several independent negative predictors for mortality in this patient population, including septic shock, respiratory failure, persistent lymphocytopenia, interstitial lung disease and high-dose glucocorticoid use.Patients who developed pneumonia while receiving glucocorticoid therapy experienced high rates of opportunistic infections, with significant morbidity and mortality. These findings should be carefully considered when determining treatment strategies for this patient population.

Challenges in the Diagnosis and Management of Bacterial Lung Infections in Solid Organ Recipients: A Narrative Review

Respiratory infections pose a significant threat to the success of solid organ transplantation, and the diagnosis and management of these infections are challenging. The current narrative review addressed some of these challenges, based on evidence from the literature published in the last 20 years. Specifically, we focused our attention on (i) the obstacles to an etiologic diagnosis of respiratory infections among solid organ transplant recipients, (ii) the management of bacterial respiratory infections in an era characterized by increased antimicrobial resistance, and (iii) the development of antimicrobial stewardship programs dedicated to solid organ transplant recipients.

Role of bronchoalveolar lavage in the management of immunocompromised patients with pulmonary infiltrates

Pulmonary infiltrates are a significant cause of morbidity and mortality in immunocompromised patients and remain a diagnostic challenge due to the broad range of etiologies that include infection and malignancy. Empiric therapy may be sub-optimal and can adversely impact outcome. Therefore, a confirmed diagnosis is necessary and flexible bronchoscopy with bronchoalveolar lavage (BAL) may be a useful diagnostic tool. Samples are obtained for microbiological and cytological testing, but the procedure carries risk of complications including the adverse events related to moderate sedation. A review of published literature on BAL in immunocompromised patients from the year 2000 was undertaken focusing on diagnostic yield, complication rate, mortality as well as factors impacting these outcomes. Studies in which the majority of patients were supported on mechanical ventilation were excluded. A total of 23 studies (7 prospective and 16 retrospective) met inclusion criteria. This covered 3,395 procedures in 3,192 patients with a mean age of 47.4 years; 60.3% male gender. Diagnostic yield ranged from 26% to 69% with no clear association between diagnostic yield and etiology of immunosuppression or clinical/radiological presentation. Post BAL modification of treatment as an indicator for clinical utility ranged from 11% to 84%; and complication rate ranged from 1% to 52%. No specific factors were associated with increased adverse event rate. This review provides a summary of the data on the use of BAL for diagnosis of pulmonary infiltrates in immunocompromised patients, highlighting the heterogeneity of patients, significant variation in findings reported and the need for more data to optimize patient selection.

Chest X-ray and chest CT findings in patients diagnosed with pulmonary tuberculosis following solid organ transplantation: a systematic review

The objective of this systematic review was to select articles including chest X-ray or chest CT findings in patients who developed pulmonary tuberculosis following solid organ transplantation (lung, kidney, or liver). The following search terms were used: "tuberculosis"; "transplants"; "transplantation"; "mycobacterium"; and "lung". The databases used in this review were PubMed and the Brazilian Biblioteca Virtual em Saúde (Virtual Health Library). We selected articles in English, Portuguese, or Spanish, regardless of the year of publication, that met the selection criteria in their title, abstract, or body of text. Articles with no data on chest CT or chest X-ray findings were excluded, as were those not related to solid organ transplantation or pulmonary tuberculosis. We selected 29 articles involving a collective total of 219 patients. The largest samples were in studies conducted in Brazil and South Korea (78 and 35 patients, respectively). The imaging findings were subdivided into five common patterns. The imaging findings varied depending on the transplanted organ in these patients. In liver and lung transplant recipients, the most common pattern was the classic one for pulmonary tuberculosis (cavitation and "tree-in-bud" nodules), which is similar to the findings for pulmonary tuberculosis in the general population. The proportion of cases showing a miliary pattern and lymph node enlargement, which is most similar to the pattern seen in patients coinfected with tuberculosis and HIV, was highest among the kidney transplant recipients. Further studies evaluating clinical data, such as immunosuppression regimens, are needed in order to improve understanding of the distribution of these imaging patterns in this population.

Utility of fiber-optic bronchoscopy in pulmonary infections among abdominal solid-organ transplant patients: A comprehensive review

Pulmonary infections are frequent complications in abdominal solid-organ transplantation (aSOT) which may threaten patient and allograft survival. Accurate diagnosis and treatment of pulmonary infections in this population can be challenging. Immunosuppressive therapy not only increases the risk of acquiring opportunistic and non-opportunistic infections, but it also impairs the inflammatory responses associated with microbial invasion which in an otherwise normal host produce clinical and radiologic responses that allow for early identification of the offending pathogen. Serologic testing is not a reliable diagnostic modality. Direct microbiological sampling is often necessary to make a definitive diagnosis early in the clinical course to optimize timely, targeted therapy while reducing the risk of developing antimicrobial resistance, and minimize adverse effects of therapy, if any. Fiber-optic bronchoscopy (FOB) with bronchoalveolar lavage (BAL) or transbronchial lung biopsy (TBB) offers such diagnostic advantage and possesses a potential therapeutic value too. This comprehensive review discusses the potential benefits of FOB alongside its risks and complications, indications and contraindications, and techniques. Additionally, the essay highlights FOB's utility and yield specifically with regard to type and timing of infections in aSOT patients.

The Distribution and Resistance of Pathogens Among Solid Organ Transplant Recipients with Pseudomonas aeruginosa Infections

BACKGROUND

Pseudomonas aeruginosa infection remains a life-threatening complication after solid organ transplantation (SOT). We aimed to investigate the distribution and drug susceptibility of pathogens, and clinical characteristics of SOT recipients with Pseudomonas aeruginosa infections.

MATERIAL/METHODS

A total of 55 SOT recipients who developed 61 episodes of Pseudomonas aeruginosa infections between January 1, 2003 and July 31, 2015 were retrospectively analyzed. The distribution and the drug susceptibility of Pseudomonas aeruginosa were reviewed.

RESULTS

The most common site from which 61 Pseudomonas aeruginosa rods were isolated were the lungs (57.4%, n=37), followed by the blood (27.9%, n=17). There were 35, 18, and 9 recipients accompanied with a serum creatinine level of >1.5 mg/dL, lymphocyte count of <300/mm(3), and a serum albumin level of <30 g/L, respectively. Seven patients each presented with white blood cell count of >15,000/mm(3) and platelet count of <50,000/mm(3). There were 6 (10.9%) cases of septic shocks and 18 (32.7%) deaths. Antibiotic resistance rate of all Pseudomonas aeruginosa to 4 of 10 antibiotics investigated was more than 50%. Of these 61 Pseudomonas aeruginosa isolates, 47.5% were carbapenem-resistant. The rods were relatively sensitive to piperacillin-tazobactam, levofloxacin, amikacin, and cefoperazone-sulbactam (resistance rate <40%).

CONCLUSIONS

The clinical presentation of Pseudomonas aeruginosa infections included high body temperature, decreased platelet count, elevated white blood cell count, a high nosocomial origin and mortality, and onset in the late period after transplantation. According to our findings, piperacillin-tazobactam, levofloxacin, amikacin, and cefoperazone-sulbactam, alone or combination, are recommended to treat SOT recipients with Pseudomonas aeruginosa infections.

Approach to the Solid Organ Transplant Patient with Suspected Fungal Infection

In solid organ transplant (SOT) recipients, invasive fungal infections (IFIs) are associated with significant morbidity and mortality. Detection of IFIs can be difficult because the signs and symptoms are similar to those of viral or bacterial infections, and diagnostic techniques have limited sensitivity and specificity. Clinicians must rely on knowledge of the patient's risk factors for fungal infection to make a diagnosis. The authors describe their approach to the SOT recipient with suspected fungal infection. The epidemiology of IFIs in the SOT population is reviewed, and a syndromic approach to suspected IFI in SOT recipients is described.

An Approach to a Pulmonary Infiltrate in Solid Organ Transplant Recipients

The onset of a pulmonary infiltrate in a solid organ transplant (SOT) recipient is both a challenging diagnostic and therapeutic challenge. We outline the potential aetiologies of a pulmonary infiltrate in a SOT recipient, with particular attention paid to fungal pathogens. A diagnostic and empirical therapy approach to a pulmonary infiltrate, especially invasive fungal disease (IFD) in SOT recipients, is provided.

Pneumococcal disease in adult solid organ transplantation recipients

In solid organ transplant (SOT) recipients, Streptococcus pneumoniae can cause substantial morbidity and mortality ranging from non-invasive to invasive diseases, including pneumonia, bacteremia, and meningitis, with a risk of invasive pneumococcal disease 12 times higher than that observed in non-immunocompromised patients. Moreover, pneumococcal infection has been related to graft dysfunction. Several factors have been involved in the risk of pneumococcal disease in SOT recipients, such as type of transplant, time since transplantation, influenza activity, and nasopharyngeal colonization. Pneumococcal vaccination is recommended for all SOT recipients with 23-valent pneumococcal polysaccharides vaccine. Although immunological rate response is appropriate, it is lower than in the rest of the population, decreases with time, and its clinical efficacy is variable. Booster strategy with 7-valent pneumococcal conjugate vaccine has not shown benefit in this population. Despite its relevance, there are few studies focused on invasive pneumococcal disease in SOT recipients. Further studies addressing clinical, microbiological, and epidemiological data of pneumococcal disease in the transplant setting as well as new strategies for improving the protection of SOT recipients are warranted.