Infections in transplant patients

Recipients of solid organ transplants (SOT) need primary care providers (PCPs) who are familiar with their unique needs and understand the lifelong infectious risks faced by SOT patients because of their need for lifelong immunosuppressive medications. SOT recipients can present with atypical and muted manifestations of infections, for which the knowledgable PCP will initiate a comprehensive evaluation. The goal of this article is to familiarize PCPs with the infectious challenges facing SOT patients. General concepts are reviewed, and a series of patient cases described that illustrate the specific learning points based on common presenting clinical symptoms.

Colonic mucormycosis presented with ischemic colitis in a liver transplant recipient

Mucormycosis is an uncommon opportunistic fungal infection with high mortality in liver transplant recipients. Mucormycosis of the gastrointestinal tract can manifest with features similar to ischemic colitis. Typically signs and symptoms of non-gangrenous ischemic colitis resolve spontaneously within 24-48 h. On the other hand, the clinical course of the mucormycosis is commonly fulminant. We encountered a case of invasive fungal colitis presenting with abdominal pain and hematochezia in a liver transplant recipient. Endoscopic examination showed multiple shallow ulcerations and edema with mucosal friabilities on the sigmoid and distal descending colon, which was consistent with ischemic colitis. However, the histological examination obtained from endoscopic biopsies showed fungal hyphae with surrounding inflammatory cells and mucosal necrosis. The patient was successfully managed with antifungal agent without surgical treatment. Thus, early diagnosis and treatment is essential for improving the prognosis of invasive fungal infection after liver transplantation.

[Pathogenic analysis of solid organ transplant recipients with pulmonary opportunistic infections via bronchoscopy]

OBJECTIVE

To evaluate the diagnostic utility of bronchoscopy in solid organ transplant recipients with pulmonary opportunistic infections.

METHODS

From December 2006 to September 2011, 117 cases of bronchoscopy with protected specimen brush and bronchoalveolar lavage were performed in 114 solid organ transplant recipients at Tianjin First Central Hospital. The indication for bronchoscopy was suspected pulmonary infections. The bronchoscopic manifestations were described and the specimens analyzed with regards to bacteriology, cytomegalovirus, P carinii, mycobacterium tuberculosis and other fungal cultures.

RESULTS

A definite infectious etiology was confirmed in 63 patients (53.8%). And opportunistic infections were the most frequent etiology (56/63, 88.9% including 7 cases with two mixed opportunistic infections). Among 63 pathogens, P carinii was demonstrated in 36 episodes, cytomegalovirus in 24 episodes and mycobacterium tuberculosis in 3 episodes. Bacterial infections (mainly Gram-negative) accounted for 16 of 63 episodes (25.9% including 9 cases with mixed opportunistic/bacterial infection). In accordance with the diagnostic results, antibiotic treatment was changed in 45 cases.

CONCLUSIONS

As an extremely useful tool, bronchoscopy is of great value for pathogenic detection in transplant recipients with suspected pulmonary infections, especially for opportunistic infections. And the bronchoscopic findings may guide targeted antimicrobial therapy.

Infectious complications in patients with lung cancer

Infections remain a part of the natural course of cancer. During the course of their disease, patients with lung cancer frequently present with an infection that can ultimately be fatal. Pathogenesis of infectious syndromes is usually determined by the underlying disease, as well as, the iatrogenic manipulations that occur during its management. Hence, lung cancer infections include lower respiratory tract infections in the context of COPD, aspiration, obstruction and opportunistic infections due to immunosuppression. Moreover, treatment-related infectious syndromes including post operative pneumonia, febrile neutropenia and superimposed infection following radiation/chemotherapy toxicity is common. Importantly, diagnosis of infection in the febrile lung cancer patient is challenging and requires a high index of suspicion in order to distinguish from other causes of fever, including malignant disease and pulmonary embolism. Prompt initiation of treatment is pivotal to avoid increased mortality. Careful consideration of infection pathogenesis can predict most likely pathogens and guide antibiotic management, thus, ensuring most favourable outcome.

Dermatic Scedosporium apiospermum infection after autologous bone marrow transplantation

Infection with Scedosporium apiospermum (S. apiospermum) is rare, although it is associated with a high fatality rate, especially in immunosuppressed patients. A 23-year-old man with acute myelogenous leukemia (AML) (M2) who was pretreated with chemotherapy for autologous bone marrow transplantation developed a skin ulcer on the left groin. After a culture study demonstrated the presence of S. apiospermum, voriconazole was administered and the lesion rapidly improved. Since a diagnosis of S. apiospermum continues to depend on the results of a fungal culture and most isolates of S. apiospermum are resistant to amphotericin B, voriconazole should be considered as the first choice when "mold" is thought to be the causative organism.

The intestinal environment of surgical injury transforms Pseudomonas aeruginosa into a discrete hypervirulent morphotype capable of causing lethal peritonitis

BACKGROUND

Secondary peritonitis continues to carry a high mortality rate despite the aggressive use of imaging, drainage, and antibiotics. Although host factors and microbial burden contribute to the outcome of peritonitis, we propose a role for bacterial virulence as a determinant of outcome from peritonitis. Bacterial virulence is an inducible trait that is activated in response to specific local "cues" that we have previously shown to be present in the mouse gut exposed to surgical stress and injury.

METHODS

Pseudomonas aeruginosa was harvested after its intestinal inoculation into the cecum of mice subjected to surgical injury (30% hepatectomy) or sham surgery (controls). Harvested strains were then injected into the peritoneum of noninjured (naïve) mice and mortality determined.

RESULTS

P. aeruginosa harvested from the intestines of surgically injured mice caused 100% mortality, whereas strains harvested from control mice caused no mortality. Among recovered strains, a distinct P. aeruginosa morphotype (wrinkled shape) was shown to cause lethal peritonitis compared to smooth-shaped strains, which were nonlethal. Wrinkled strains were associated with a tendency to elicit a more proinflammatory response in mice compared to smooth-shaped strains.

CONCLUSION

Surgical injury transforms the morphotype of intestinal P. aeruginosa to express a hypervirulent response in the peritoneum of mice. Enhanced virulence of intestinal pathogens in response to surgical injury may play an important role in predicting the outcome of peritonitis.

Oral infections caused by yeasts in patients with head and neck cancer undergoing radiotherapy. Identification of the yeasts and evaluation of their antifungal susceptibility

Yeasts occur as part of the normal human microbiota. Nevertheless, some species are opportunistic, affecting immunocompromised patients such as those undergoing oncologic treatment.

OBJECTIVE

To detect the presence of yeasts in patients suffering from head and neck cancer who are receiving radiation therapy and display lesions in the oral cavity, compatible with candidiasis; and to evaluate the antifungal susceptibility of the isolates recovered.

METHODS

Sixty samples from patients were obtained by swabbing the oral mucosa. Identification of isolates were performed by classical taxonomic, morphological and biochemical methods as well as by using commercial identification kits. Susceptibility to antifungal drugs was determined by the agar diffusion method with Neosensitabs(®) disks.

RESULTS

Forty-six samples (77%) yielded positive findings, and species recovered were: Candida albicans (22 isolates), Candida tropicalis (13 isolates), Candida parapsilosis (six strains), Candida krusei (three strains), Candida dubliniensis and Saccharomyces cerevisiae (one each). All strains were susceptible to itraconazole, clotrimazole, voriconazole, nystatin and amphotericin B. On the other hand, 65% of strains were miconazole-susceptible while 35%, showed intermediate susceptibility. With regard to ketoconazole, only three strains (7%) corresponding to C. albicans (one isolate) and C. krusei (two isolates) displayed intermediate susceptibility. Only C. krusei strains were resistant to fluconazole while all the other species were susceptible. Eventually, only six isolates (13%) were susceptible to terbinafine while the remaining strains were resistant in vitro.

CONCLUSION

Early detection of etiological agents causing lesions, as well as the evaluation of their susceptibility to commonly used drugs, are crucial in order to choose the appropriate treatment that will minimize complications while improving the quality of patients' lives.

[Oncological intensive care: 2011 year's review]

The objective of this paper is to review the literature published in 2011 in the field of intensive care and emergency related to oncology. Are discussed because of new original publications: prognosis, resuscitation techniques, oncologic emergencies, serious toxicities of cytotoxic chemotherapy and targeted therapies, complicated aplastic anemia, toxicity of bisphosphonates, respiratory complications, pulmonary embolism and neurological complications.

[Infections and fingolimod]

INTRODUCTION

Fingolimod is the first approved drug with oral availability for the treatment of relapsing multiple sclerosis.

AIMS

To review the mechanism of action of fingolimod and its relationship with the development of infections. To propose preventive measures for those patients who are receiving the drug or will initiate a new treatment. In addition, the role of fingolimod in the development of progressive multifocal leukoencephalopathy on the basis of recent knowledge of its pathophysiology will be discussed.

DEVELOPMENT

The mechanism of action of fingolimod is based on an antagonic effect on the sphingosine 1-phospate receptors that will generate an inhibition of the egress of naive and central memory lymphocytes into the bloodstream, allowing the free recirculation of memory effectors T lymphocytes. This effect will produce lymphopenia. Fingolimod-associated lymphopenia is a consequence of lymphocyte redistribution, and it is selective and reversible. There is no evidence of higher number of opportunistic and non-opportunistic infections in comparison to placebo or interferon beta-1a in patients receiving fingolimod. However, two patients developed severe herpetic infections under fingolimod.

CONCLUSIONS

Fingolimod induce a selective and reversible lymphopenia that, taking into account the most recent available data, does not seem to be associated with higher risk of opportunistic infections due to a preservation of immuno-surveillance. The risk of herpesvirus infection should be taken into consideration and more studies are warranted to confirm if an association of these infections with the use of fingolimod exists.

Viral infection in renal transplant recipients

Viruses are among the most common causes of opportunistic infection after transplantation. The risk for viral infection is a function of the specific virus encountered, the intensity of immune suppression used to prevent graft rejection, and other host factors governing susceptibility. Although cytomegalovirus is the most common opportunistic pathogen seen in transplant recipients, numerous other viruses have also affected outcomes. In some cases, preventive measures such as pretransplant screening, prophylactic antiviral therapy, or posttransplant viral monitoring may limit the impact of these infections. Recent advances in laboratory monitoring and antiviral therapy have improved outcomes. Studies of viral latency, reactivation, and the cellular effects of viral infection will provide clues for future strategies in prevention and treatment of viral infections. This paper will summarize the major viral infections seen following transplant and discuss strategies for prevention and management of these potential pathogens.

Immunotherapy in inflammatory bowel disease

Inflammatory bowel disease affects an increasing number of patients worldwide and is associated with significant morbidity. The dysregulation of the immune system with increased expression of proinflammatory cytokines and increased mucosal expression of vascular adhesion molecules play an important role in its pathogenesis. Strategies targeting TNF-alpha and alpha4-integrin have led to the development of novel therapies for treatment of patients with IBD. This article discusses the efficacy of immunologic agents currently approved for treating Crohn disease and ulcerative colitis and reviews the risks and challenges associated with their use.

Biologic therapy and risk of infection

Biologic compounds are being used more frequently to treat a multitude of systemic inflammatory conditions. These novel compounds are composed of antibodies or other peptides that act through one of three mechanisms: inhibiting inflammatory cytokine signaling (typically tumor necrosis factor or TNF), inhibiting T-cell activation, or depleting B-cells. The increase in use and ever expanding list of new immune modulating therapies make knowledge of the infectious complications associated with immune modulation even more important. Of particular concern is the risk for developing atypical and opportunistic infections including tuberculosis, herpes zoster, Legionella pneumophila, and Listeria monocytogenes.

Infectious disease trends among immunocompromised hosts

With our rapidly ageing population and advancing treatments for patients with haematological, oncologic and rheumatological diseases, there are increasing numbers of immunocompromised patients presenting to primary care and general hospitals with opportunistic infections. This review considers the trends of these infections across four representative subgroups: fungal infections following haematopoietic stem cell transplant; viral infections post solid organ transplant; mycobacterial infections during treatment with targeted biological agents; and bacterial infections as a cause of fever in neutropenia. We also consider the impact of host, pathogens, environments and treatments on the epidemiology and outcomes of these infections.

Opportunistic posttransplantation virus infections in renal transplant recipients

BACKGROUND

Opportunistic virus infection is one of the most common complications in renal transplant (RT) recipients. Cytomegalovirus (CMV) and BK virus (BKV) are important pathogens and each of these infections affects the other. In contrast, there is only limited information on JC virus (JCV) infection and its relation to CMV infection in RT recipients. This prospective study investigated the rates of JCV and CMV infections and their risk factors and correlations.

METHODS

We studied 52 RT recipients. JCV and CMV were detected using nested qualitative polymerase chain reaction assays of urine. The clinical characteristics of JCV and CMV infection were compared and risk factors analyzed with the use of binary logistic regression.

RESULTS

JCV and CMV were detected in 40.4% and 34.6% of the RT recipients, respectively. Cyclosporine (CsA) was a risk factor for both JCV and CMV infection (odds ratio [OR] 7.187; P=.002; OR 4.182; P=.021); CMV infection was a risk factor for JCV infection (OR 3.900; P=.039).

CONCLUSIONS

JCV and CMV infections are common in RT recipients. CsA is a risk factor for both JCV and CMV infection. JCV infection is related to CMV infection.

Infections of Blastocystis hominis and microsporidia in cancer patients: are they opportunistic?

Chemotherapy can cause immunosuppression, which may trigger latent intestinal parasitic infections in stools to emerge. This study investigated whether intestinal parasites can emerge as opportunistic infections in breast and colorectal cancer patients (n=46 and n=15, respectively) undergoing chemotherapy treatment. Breast cancer patients were receiving a 5-fluorouracil/epirubicin/cyclophosphamide (FEC) regimen (6 chemotherapy cycles), and colorectal cancer patients were receiving either an oxaliplatin/5-fluorouracil/folinic acid (FOLFOX) regimen (12 cycles) or a 5-fluorouracil/folinic acid (Mayo) regimen (6 cycles). Patients had Blastocystis hominis and microsporidia infections that were only present during the intermediate chemotherapy cycles. Thus, cancer patients undergoing chemotherapy should be screened repeatedly for intestinal parasites, namely B. hominis and microsporidia, as they may reduce the efficacy of chemotherapy treatments.

Infections in postmenopausal women with osteoporosis treated with denosumab or placebo: coincidence or causal association?

Serious adverse events of infections that occurred in subjects receiving denosumab or placebo in the Fracture Reduction Evaluation of Denosumab in Osteoporosis every 6 Months (FREEDOM) study were examined in detail. Serious adverse events of infections in denosumab subjects had heterogeneous etiology, with no clear clinical pattern to suggest a relationship to time or duration of exposure to denosumab.

INTRODUCTION

Denosumab reduces the risk for new vertebral, hip, and nonvertebral fractures compared with placebo. In the pivotal phase 3 fracture trial (FREEDOM), the overall safety profile and incidence of adverse events including adverse events of infections were similar between groups. Serious adverse events of erysipelas and cellulitis were more frequent in denosumab-treated subjects. In this report, we further evaluate the details of infectious events in FREEDOM to better understand if RANKL inhibition with denosumab influences infection risk.

METHODS

FREEDOM was an international multicenter, randomized, double-blind, placebo-controlled study in postmenopausal women with osteoporosis randomly assigned to receive placebo (n = 3,906) or denosumab 60 mg every 6 months (n = 3,902). The incidence of adverse events and serious adverse events categorized within the Medical Dictionary for Regulatory Activities system organ class, "Infections and Infestations," was compared between the placebo and denosumab groups by body systems and preferred terms. The temporal relationship between occurrence of serious adverse events of infections of interest and administration of denosumab was explored.

RESULTS

Serious adverse events of infections involving the gastrointestinal system, renal and urinary system, ear, and endocarditis were numerically higher in the denosumab group compared with placebo, but the number of events was small. No relationship was observed between serious adverse events of infections and timing of administration or duration of exposure to denosumab.

CONCLUSIONS

Serious adverse events of infections that occurred with denosumab treatment had heterogeneous etiology, with no clear clinical pattern to suggest a relationship to time or duration of exposure to denosumab.

Serum immunoglobulin G is a marker for the risk of opportunistic infection in steroid-dependent severe asthmatic patients

BACKGROUND

Approximately 10% of asthmatic patients are refractory to inhaled corticosteroids and therefore need long-term oral corticosteroid therapy, which is associated with a risk of opportunistic infections due to immunosuppression.

OBJECTIVE

To ascertain the applicability of serum Immunoglobulin G (IgG) as a marker for predicting the risk of opportunistic infections in patients undergoing oral corticosteroid therapy.

METHODS

Three thousand asthmatics were screened, and 14 patients who had been administered daily oral corticosteroids for more than two years were enrolled. The patients enrolled were maintained under observation with ordinary check-ups and treatments for one year. After the observation period, the patients were divided into two groups according to the presence (OPI) or absence (non-OPI) of opportunistic infections during the period. The differences in the clinical parameters between the groups were investigated.

RESULTS

There were no statistically significant differences in age, forced expiratory volume in 1 second (FEV(1)), smoking status or serum albumin between the groups. The serum IgG level of the OPI group was significantly lower than that of the non-OPI group (567.2±151.1 mg/dL vs. 931.6±198.8 mg/dL, p<0.01). The average total dose of corticosteroids administered during the one year period was higher in the OPI group (2,633±554.2 mg) than that in the Non-OPI group (1,793±466.2 mg) (p<0.05). There was a significant correlation between the serum IgG and total dose of corticosteroids administered during the one-year period (r = -0.75, p<0.01). The area under the receiver operating characteristic curve regarding the serum IgG and incidence of opportunistic infections was 0.97, which suggests that the serum IgG level has a high accuracy for predicting the risk of opportunistic infections.

CONCLUSION

The serum IgG was therefore found to be a useful marker for predicting the risk of opportunistic infections in steroid-dependent asthmatics.