Comparing the diagnostic value of targeted with metagenomic next-generation sequencing in immunocompromised patients with lower respiratory tract infection.

BACKGROUND: Accurate identification of the etiology of lower respiratory tract infections (LRTI) is crucial, particularly for immunocompromised patients with more complex etiologies. The advent of next-generation sequencing (NGS) has enhanced the effectiveness of pathogen detection. However, assessments of the clinical diagnostic value of targeted NGS (tNGS) in immunocompromised patients with LRTI are limited. METHODS: To evaluate the diagnostic value of tNGS in immunocompromised patients with LRTI, a total of 88 patients, of whom 54 were immunocompromised, were enrolled. These patients underwent tNGS testing of bronchoalveolar lavage fluid (BALF). Results from both metagenomic next-generation sequencing (mNGS) and conventional microbiological tests (CMT) were also available for all participants. The performance of tNGS was assessed by comparing its findings against mNGS, CMT, and the clinical composite diagnosis. RESULTS: In the cohort of 88 patients, tNGS showed comparable diagnostic value to mNGS and was significantly superior to CMT. Compared to CMT and composite reference standard, tNGS showed sensitivity of 94.55% and 90.48%, respectively. In immunocompromised patients, despite a more diverse pathogen variety, tNGS maintained similar sensitivity to mNGS and outperformed CMT. tNGS positively influenced etiologic diagnosis and antibiotic decision-making in 72.72% of cases, leading to a change in antibiotic regimen in 17.05% of cases. We also compared the detection of microbial nucleic acids by tNGS with mNGS and found that tNGS could identify 87.99% of the microbial nucleic acids identified by mNGS. CONCLUSION: In summary, our study demonstrated that tNGS offers promising clinical diagnostic accuracy in immunocompromised patients, as evidenced by its favorable comparison with CMT, the composite reference standard, and mNGS.

Progressive Multifocal Leukoencephalopathy confined to the posterior fossa as the presenting manifestation of HIV in a paediatric patient.

Progressive Multifocal Leukoencephalopathy (PML), primarily affecting immunocompromised individuals due to the John Cunningham virus (JC), is common in HIV-positive adults but rare in paediatrics. We present a unique case of a 14-year-old female with PML as the initial manifestation of HIV, with MRI lesions isolated to the posterior fossa. Initial symptoms included fever and rash, progressing to neurological deficits and ataxia. Severe immune suppression due to HIV and JC virus in the cerebrospinal fluid were confirmed. Management included immune reconstitution therapy (antiretroviral treatment) and supportive care. Despite interventions, the patient had a slow recovery with significant residual neurological sequelae. Timely recognition of Immune Reconstitution Inflammatory Syndrome (IRIS) and steroid initiation proved helpful. Antiretroviral therapy improved the survival rate of HIV-related PML, but long-term neurological sequelae, especially in posterior fossa cases, significantly impact the patient's quality of life. This case highlights diagnostic and treatment challenges in paediatric PML, particularly with atypical lesions location.

Strategies for Diagnosing and Treating Disseminated Methicillin-Sensitive Staphylococcus aureus Infections: Insights From a Pustular Eruption.

A 63-year-old immunocompromised male with a history of renal transplant and stage III large B-cell non-Hodgkin lymphoma undergoing rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) therapy presented with fever and a disseminated pustular eruption. Initial laboratory values indicated septicemia. Differential diagnoses included Sweet's syndrome, septic emboli, and leukocytoclastic vasculitis. Punch biopsies and bacterial cultures confirmed disseminated methicillin-sensitive Staphylococcus aureus (MSSA) infection. Histopathology revealed intraepidermal vesiculopustules and bacterial cocci colonies in the superficial dermis, suggesting hematogenous spread. The patient's indwelling venous access port was identified as the infection source and removed. Treatment included antibiotics such as cefepime, vancomycin, fluconazole, and acyclovir, as well as filgrastim for neutropenia. Following port removal and a four-week course of ceftriaxone, the patient's condition improved. This case highlights the importance of clinicopathologic correlation in diagnosing and managing disseminated staphylococcal infections in immunocompromised patients. The rare presentation of vesiculopustular eruptions secondary to MSSA emphasizes the need for prompt identification and treatment to prevent severe complications. This report contributes to the limited literature on disseminated staphylococcal infections presenting as vesiculopustular eruptions in immunocompromised individuals.

Multidrug-Resistant Bacteria in Immunocompromised Patients.

The increasing incidence of antibiotic resistance in bacteria is a major problem in terms of therapeutic options, especially in immunocompromised patients, such as patients from intensive care units (ICUs), HIV-positive patients, patients with malignancies or transplant patients. Commensal bacteria, especially anaerobes, serve to maintain microbial stability by preventing overpopulation with pathogenic bacteria. In immunocompromised patients, microbiota imbalance caused by antibiotic therapy and decreased host immunity favors intestinal overpopulation with pathogenic species, leading to increased bacterial translocation and susceptibility to systemic infections. Infections with multidrug-resistant (MDR) bacteria pose major challenges to the establishment of appropriate treatment and lead to increased mortality. Asymptomatic colonization with MDR bacteria usually precedes infection and tends to persist for long periods of time, and in immunocompromised patients, colonization with MDR bacteria is a risk factor for systemic infections. This review aims to assess the relation between colonization and infection with MDR bacteria in immunocompromised patients such as ICU patients, HIV-positive patients and cancer patients and to identify the prevalence and patterns of MDR bacterial colonization and infection in this category of patients.

[Lactobacillemia: A Rare Entity in Immunocompromised Patients. Description of a Clinical Case and Literature Review].

Bacteremia caused by Lactobacillus is rare, data on its clinical significance are based only on case reports and a limited number of studies, often difficult to interpret. Lactobacillus species is a commensal colonizer of the mouth, gastrointestinal and genitourinary tract. Its significance as a pathogen is overlooked frequently. The diagnosis of these infections requires a mutual relationship between the physician and the microbiologist to rule out contamination risk. Most patients with Lactobacillus bacteremia are immunosuppressed or patients at increased risk of symptomatic bacteremia with comorbidities, treated with broad-spectrum antibiotics and have indwelling venous catheters. Risk factors related to Lactobacillus bacteremia include impaired host defenses and severe underlying diseases, as well as prior surgery and prolonged antibiotic therapy ineffective for lactobacilli. We describe an unusual case of a woman, on chronic hemodialysis treatment, with a sepsis due to Lactobacillus casei and review the literature.

Case reports of persistent SARS-CoV-2 infection outline within-host viral evolution in immunocompromised patients.

BACKGROUND: SARS-CoV-2 is responsible for the ongoing global pandemic, and the continuous emergence of novel variants threatens fragile populations, such as immunocompromised patients. This subgroup of patients seems to be seriously affected by intrahost viral changes, as the pathogens, which are keen to cause replication inefficiency, affect the impaired immune system, preventing efficient clearance of the virus. Therefore, these patients may represent an optimal reservoir for the development of new circulating SARS-CoV-2 variants. The following study aimed to investigate genomic changes in SARS-CoV-2-positive immunocompromised patients over time. METHODS: SARS-CoV-2-positive nasopharyngeal swabs were collected at different time points for each patient (patient A and patient B), extracted and then analyzed through next-generation sequencing (NGS). The resulting sequences were examined to determine mutation frequencies, describing viral evolution over time. CASE PRESENTATION: Patient A was a 53-year-old patient with onco-hematological disease with prolonged infection lasting for 51 days from May 28th to July 18th, 2022. Three confirmed SARS-CoV-2-positive samples were collected on May 28th, June 15th and July 4th. Patient B was 75 years old and had onco-hematological disease with prolonged infection lasting for 146 days. Two confirmed positive SARS-CoV-2 samples were collected at the following time points: May 21st and August 18th. CONCLUSION: Heat map construction provided evidence of gain and/or loss of mutations over time for both patients, suggesting within-host genomic evolution of the virus. In addition, mutation polymorphisms and changes in the SARS-CoV-2 lineage were observed in Patient B. Sequence analysis revealed high mutational pattern variability, reflecting the high complexity of viral replication dynamics in fragile patients.

Disseminated Infection Caused by Nocardia cyriacigeorgica in Immunocompromised Patient Confirmed by Whole Genome Sequencing.

INTRODUCTION: Nocardia spp. is an opportunistic pathogen capable of causing localized and disseminated infections in immunocompromised hosts. It is critical for serious infections to have an early and accurate identification of this pathogen in order to enable timely and focused combination antimicrobial treatment. CASE PRESENTATION: We describe the case of an 87-year-old patient previously treated for myasthenia gravis with corticosteroids and azathioprine. Patient was admitted at the emergency department with clinical signs of sepsis with cellulitis of right hand associated with injury acquired after gardening and trimming roses and did not respond to empirical antimicrobial treatment. Computerized tomography revealed pulmonary infiltrates with inflammatory etiology. Nocardia cyriacigeorgica was cultivated from blood culture, skin swab, abscess aspirate, and endotracheal aspirate and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), 16S rRNA sequencing, and whole genome sequencing (WGS). Susceptibility testing was performed with E-test (bioMerieux, Marcy-l'Étoile, France), and corresponding resistance genes were detected by WGS. Resistance to amoxicillin-clavulanate, azithromycin, ciprofloxacin, and vancomycin was detected by both methods. Despite all interventions and the patient receiving antimicrobial treatment including imipenem-cilastatin, amikacin, and trimethoprim-sulfamethoxazole, the course and outcome of infection were unfavorable. CONCLUSION: We would like to emphasize the need to consider the possibility of disseminated Nocardia infection in immunocompromised patients, especially in patients receiving long-term corticosteroid treatment with skin infections and/or cavitary lung lesions, especially if these do not improve with standard antimicrobial treatment. Precise species identity provides a critical guide for physicians in the choice of targeted treatment. Thanks to MALDI-TOF MS, Nocardia spp. identification is now available in routine lab work. WGS is still inevitable for the identification of uncommon and novel species due to the high sequence similarities between closely related species and the genetic diversity of that genus.

"REAl LIfe" observational study on the effectiveness of Evusheld prophylaxis against SARS-CoV-2 omicron variants in vaccine non-responder immunocompromised patients (REALISE).

BACKGROUND: Infection by SARS-CoV2 has become a challenge, especially for immunocompromised patients who show a weaker humoral response to COVID-19 vaccine. Tixagevimab+cilgavimab (Evusheld) is a combination of human monoclonal antibodies that can be used for pre-exposure prophylaxis to prevent infection or disease by SARS-CoV2. OBJECTIVES: Our study aimed to investigate the effectiveness of Evusheld by comparing an Exposed and an Unexposed group. STUDY DESIGN: Immunocompromised patients were enrolled in the Evusheld Group between March and September 2022. All patients had anti-spike IgG antibody levels <260 BAU/ml before administration of Evusheld. Blood samples for serological evaluations were collected, and anti-Spike antibodies were tested. For the Unexposed Group, a serologic test was performed at enrollment and a questionnaire was performed after 6 months. RESULTS: 43 patients received Evusheld pre-exposure prophylaxis and 45 patients not receiving Evusheld were enrolled in the Unexposed group. The median age was 59.0 years in the Evusheld group, and 63.0 in the unexposed group. In the Evusheld group, during the Omicron wave in Italy, 23.3% of subjects developed symptomatic infection compared to 42.2% in the unexposed group. A majority of infections was seen in male respect to female patients. No difference in length of infection between the groups was seen. Antibody level remained higher than the basal threshold at 180 days from enrollment. CONCLUSIONS: Evusheld seems to reduce the rate of symptomatic infection in immunocompromised patients. Further data are required to determine whether this prophylaxis may have a longer-lasting effect over time.

Efficacy of Tixagevimab/Cilgavimab as Pre-Exposure Prophylaxis against Infection from SARS-CoV-2 and Severe COVID-19 among Heavily Immunocompromised Patients: A Single-Center, Prospective, Real-World Study.

BACKGROUND: COVID-19 continues to pose a threat to immunocompromised individuals, even with vaccination. The monoclonal antibodies (mAbs) tixagevimab/cilgavimab (TXG/CIL) provide targeted prophylaxis against SARS-CoV-2 with the benefit of a prolonged half-life. Although approved for COVID-19 prevention, there is limited data on their effectiveness among heavily immunocompromised populations. METHODS: We conducted a prospective, observational study at Laiko General Hospital, Athens, Greece, from August to December 2022 to investigate the efficacy of TXG/CIL as a form of pre-exposure prophylaxis in immunocompromised patients. Data on breakthrough SARS-CoV-2 infections were collected over a six-month follow-up period. RESULTS: Of the 375 participants (mean age 61.3 ± 14.1 years; 59.7% male), 76 (20.3%) developed breakthrough SARS-CoV-2 infections, with an incidence of 3.81 cases/100 patient months. Hospitalization was required for 21 patients (5.6%), with a median stay of 14 days. Seven deaths were recorded, with only one attributed to COVID-19. Previous infection (OR 0.46, 95% CI 0.26-0.82) and hybrid immunity (OR 0.52, 95% CI 0.29-0.92) can protect against new infection. Solid organ malignancy significantly increased the risk of severe outcomes among those infected (OR 7.4, 95% CI 2.2-24.7, p = 0.001). CONCLUSIONS: TXG/CIL provides effective prophylaxis against COVID-19 in immunocompromised patients. Future strategies should focus on developing new mAb combinations to address emerging SARS-CoV-2 variants and protect vulnerable populations.

Patients with immune mediated inflammatory diseases are insufficiently protected against vaccine-preventable infections.

BACKGROUND: Patients with Immune Mediated Inflammatory Diseases (IMIDs) using immunosuppressive therapy are at increased risk of infections, including vaccine-preventable infections. In this study, we aimed to evaluate whether patients with IMIDs on systemic immunosuppressive therapy are vaccinated according to current guidelines. METHODS: A survey was sent out, between August 2022 and March 2023, to all patients with IMIDs that visited the departments of dermatology, rheumatology and gastroenterology at an academic and regional hospital in Rotterdam, the Netherlands. Patient-reported vaccination status was compared to the Dutch guidelines on vaccinations in patients with chronic inflammatory diseases. RESULTS: A total of 1,905/5,987 patients responded to the survey (response rate 32%). After exclusion of patients without systemic immunosuppressive medication, the study population comprised 1,390 patients, median age 56 years (IQR 42-66) and 41% male. Most patients (92%) had been vaccinated according to the Dutch National Immunization Program. Before starting immunosuppressive therapy, 2% of the patients who were still considered at risk according to the Dutch guideline were vaccinated for measles, and 4% for diphtheria/tetanus/polio (DT-IPV). Additionally, 62% of patients received an annual influenza vaccine, 16% received a five-yearly pneumococcal vaccine, and 91% were fully vaccinated against COVID-19. CONCLUSION: Patients with IMIDs on immunosuppressive therapy are not vaccinated in accordance with the guidelines. Implementation strategies to improve the vaccination rates for patients with IMIDs should specifically focus on vaccinating against measles and diphtheria/tetanus/polio, and periodic vaccination against pneumococcal and influenza infections.

Phenotypic and genomic characterization of a small colony variant of Klebsiella pneumoniae isolated from urine of a prostate cancer case.

Small colony variants (SCVs) in Klebsiella pneumoniae are rare and understudied. We report an SCV of Klebsiella pneumoniae isolated from the urine of a prostate cancer patient undergoing prolonged radiotherapy. The strain was non-lactose fermenting, non-mucoid, slow-growing, multi-drug resistant, and showed atypical biochemical reactions and biofilm formation. On whole genome sequencing, it showed low-level virulence, sequence type 231 and gene CTX-M-15. Three major porins OmpK35, OmpK36 and OmpK37 were found. SCVs pose challenges like difficulties in identification, altered metabolism, and increased biofilm formation, which contribute to persistent infections. Radiotherapy and chemotherapy may have led to the formation of the SCV phenotype.

Hepatitis E virus and SARS-CoV-2 co-infection in an immunocompromised patient: A case report.

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis. Since the coronavirus disease 2019 (COVID-19) pandemic, immunocompromised individuals face an increased risk of HEV and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) co-infection, posing a threat of liver failure and prolonged illness. A 69-year-old male, with a history of chronic lymphocytic leukemia, was co-infected with HEV and SARS-CoV-2. Given the progressive decline in liver function post-admission, steroid therapy was initiated, which led to treatment-related complications. Additionally, the patient experienced an aggravation of COVID-19 symptoms due to persistent SARS-CoV-2 infection, effectively managed through a combination of antiviral medications and corticosteroids. This case describes the intricate clinical trajectory and therapeutic approach for managing HEV and SARS-CoV-2 co-infection, underscoring the potential efficacy of short-term corticosteroid intervention alongside comprehensive antiviral treatment.

Evaluation of the AltoStar AM16 system for the quantitation of AdV, CMV and HHV-6 DNA from clinical specimens.

The vulnerability of immunocompromised patients to common or opportunistic viral infections is particularly high. The quantitation of viral load in clinical specimens is important for the diagnosis and management of the infection and reactivation in this patient population, particularly transplant recipients. As the new regulation "IVDR" regarding in vitro diagnosis methods is about to come into effect in France, diagnostic laboratories have to implement methods and systems compatible with this new regulation. Technical performance of the AltoStar® Adenovirus (AdV), Cytomegalovirus (CMV) and human Herpesvirus-6 (HHV-6) DNA PCR Kits 1.5 was assessed on the AltoStar Automation system AM16 using reference kits in 146 clinical samples. Overall agreement in clinical specimens was 87.5 % (28/32), 96.8 % (62/64), 100 % (22/22), 100 % (28/28) and 92.8 % (26/28) for AdV, CMV (WB samples and other matrices), HHV-6 A&B respectively. Quantitative results were highly correlated and estimated to be equivalent within a 0.057-0.648 log-amount difference.We found that altona kits on The AltoStar AM16 system are suitable for clinical monitoring of AdV, CMV and HHV-6 in immunocompromised hosts.

Recurrent Fungemia Due to Candida auris.

We present a case of recurrent multidrug-resistant Candida auris (C. auris) in a patient who required multiple hospitalizations. The patient's case was complicated by interval admissions to the intensive care unit for septic and hypovolemic shock for 12 months to manage C. auris fungemia. Despite adequate isolation precautions and appropriate antifungal treatment, this case demonstrates the profound implications of this emerging pathogen, specifically regarding invasive infections. Moreover, C. auris is rapidly becoming known as a multidrug-resistant organism, which limits treatment options and thus contributes to high mortality.

Tacrolimus-induced posterior reversible encephalopathy syndrome following liver transplantation.

In this editorial, we talk about a compelling case focusing on posterior reversible encephalopathy syndrome (PRES) as a complication in patients undergoing liver transplantation and treated with Tacrolimus. Tacrolimus (FK 506), derived from Streptomyces tsukubaensis, is a potent immunosuppressive macrolide. It inhibits T-cell transcription by binding to FK-binding protein, and is able to amplify glucocorticoid and progesterone effects. Tacrolimus effectively prevents allograft rejection in transplant patients but has adverse effects such as Tacrolimus-related PRES. PRES presents with various neurological symptoms alongside elevated blood pressure, and is primarily characterized by vasogenic edema on neuroimaging. While computed tomography detects initial lesions, magnetic resonance imaging, especially the Fluid-Attenuated Inversion Recovery sequence, is superior for diagnosing cortical and subcortical edema. Our discussion centers on the incidence of PRES in solid organ transplant recipients, which ranges between 0.5 to 5 +ACU-, with varying presentations, from seizures to visual disturbances. The case of a 66-year-old male status post liver transplantation highlights the diagnostic and management challenges associated with Tacrolimus-related PRES. Radiographically evident in the parietal and occipital lobes, PRES underlines the need for heightened vigilance among healthcare providers. This editorial emphasizes the importance of early recognition, accurate diagnosis, and effective management of PRES to optimize outcomes in liver transplant patients. The case further explores the balance between the efficacy of immunosuppression with Tacrolimus and its potential neurological risks, underlining the necessity for careful monitoring and intervention strategies in this patient population.

Critical considerations for the management of acute abdomen in transplant patients.

The number of solid organ transplantations performed annually is increasing and are increasing in the following order: Kidney, liver, heart, lung, pancreas, small bowel, and uterine transplants. However, the outcomes of transplants are improving (organ survival > 90% after the 1st year). Therefore, there is a high probability that a general surgeon will be faced with the management of a transplant patient with acute abdomen. Surgical problems in immunocompromised patients may not only include graft-related problems but also nongraft-related problems. The perioperative regulation of immunosuppression, the treatment of accompanying problems of immunosuppression, the administration of cortisol and, above all, the realization of a rapidly deteriorating situation and the accurate evaluation and interpretation of clinical manifestations are particularly important in these patients. The perioperative assessment and preparation includes evaluation of the patient's cardiovascular system and determining if the patient has hypertension or suppression of the hypothalamic-pituitary-adrenal axis, or if the patient has had any coagulation mechanism abnormalities or thromboembolic episodes. Immunosuppression in transplant patients is associated with the use of calcineurin inhibitors, corticosteroids, and antiproliferation agents. Many times, the clinical picture is atypical, resulting in delays in diagnosis and treatment and leading to increased morbidity and mortality. Multidetector computed tomography is of utmost importance for early diagnosis and management. Transplant recipients are prone to infections, especially specific infections caused by cytomegalovirus and Clostridium difficile, and they are predisposed to intraoperative or postoperative complications that require great care and vigilance. It is necessary to follow evidence-based therapeutic protocols. Thus, it is required that the clinician choose the correct therapeutic plan for the patient (conservative, emergency open surgery or minimally invasive surgery, including laparoscopic or even robotic surgery).

Prophylactic antibodies inhibit spike-specific T and B cell responses after COVID-19 vaccination.

Active and passive immunization is used in high-risk patients to prevent severe courses of COVID-19, but the impact of prophylactic neutralizing antibodies on the immune reaction to the mRNA vaccines has remained enigmatic. Here we show that CD4 T and B cell responses to Spikevax booster immunization are suppressed by the therapeutic antibodies Casirivimab and Imdevimab. B cell and T cell responses were significantly induced in controls but not in antibody-treated patients. The data indicates that humoral immunity, i. e. high levels of antibodies, negatively impacts reactive immunity, resulting in blunted cellular responses upon boosting. This argues for temporal separation of vaccination efforts; with active vaccination preferably applied before prophylactic therapeutic antibody treatment.

Clinical and virological features of SARS-CoV-2 Omicron variant-infected immunocompromised patients receiving immunosuppressive medications.

BACKGROUND: The prognosis of immunocompromised individuals with COVID-19 remains a significant concern. Information regarding the clinical and virological characteristics of immunocompromised patients infected with SARS-CoV-2 during the Omicron variant period is limited. METHODS: Medical records of patients admitted to our hospital with COVID-19 during the Omicron (BA.1-5) epidemic were retrospectively reviewed. Clinical, virological (nasopharyngeal swabs and blood), and serological data were compared between immunocompromised patients receiving immunosuppressive medications (calcineurin inhibitors, mycophenolate mofetil, or steroids) and control patients not receiving immunosuppressive medications. RESULTS: Twenty-eight immunocompromised patients (25 transplant recipients) and 26 control patients were included. Fourteen of the immunocompromised patients (50%) received monoclonal antibodies. The immunocompromised group included 15 mild/moderate (53.6%), 10 severe (35.7%), and three critical (10.7%) disease severities. The mortality rate due to COVID-19 during hospitalization was 3.6% (1/28) in the immunocompromised group, with no difference between the two groups. Three cases of re-exacerbation after discharge occurred in the immunocompromised group and none in the control group. Linear regression based on nasopharyngeal real-time-PCR cycle threshold (Ct) values according to the time since symptom onset showed markedly slower viral clearance in the immunocompromised group than in the control group (Pslope = 0.078). In the immunocompromised group, patients who received monoclonal antibodies showed faster viral clearance than those who did not receive monoclonal antibodies. The convalescent anti-spike IgG titers were comparable to those in the control group in patients who received monoclonal antibodies and significantly lower than those in the control patients in patients who did not receive monoclonal antibodies (P < 0.001). The prevalence of viremia at onset was significantly higher in the immunocompromised group than in the control group (35.7%, [10/28] vs. 11.5%, [3/26]; P = 0.003). All three patients with critical disease severity in the immunocompromised group exhibited viremia, one of whom died. All three patients with viremia in the control group were critical, of whom two died. CONCLUSIONS: Immunocompromised individuals receiving immunosuppressive medications are more likely to show delayed post-infection SARS-CoV-2 viral clearance and the development of viremia, potentially resulting in worsening severity and outcomes, especially in viremic patients, even during the Omicron epidemic.

Risk of fungal exposure in the homes of patients with hematologic malignancies.

BACKGROUND: Patients with hematological malignancies are at a high risk of developing invasive fungal infections (IFI) because they undergo several cycles of treatment leading to episodes of neutropenia. In addition, they alternate between hospital stays and periods spent at home. Thus, when an IFI is diagnosed during their hospital stays, it is highly challenging to identify the origin of the fungal contamination. The objective of this study was to analyze at home fungal exposure of 20 patients with leukemia by taking air and water samples in their living residence. METHODS: Air was sampled in 3 rooms of each home with a portable air system impactor. Tap water was collected at 3 water distribution points of each home. For positive samples, fungi were identified by mass spectrometry or on the basis of their morphological features. RESULTS: 85 % of homes revealed the presence in air of Aspergillus spp. and those belonging to the section Fumigati presented the highest concentrations and the greatest frequency of isolation. Concerning mucorales, Rhizopus spp. and Mucor spp. were isolated in air of 20 % and 5 % of dwellings, respectively. In 4 homes, more than 70 % of the fungal species identified in air were potential opportunists; these were mainly Aspergillus spp. with concentrations greater than 20 cfu/m3. The water samples revealed the presence of Fusarium in 3 dwellings, with concentrations up to 80 cfu/L. Finally, for one patient, fungal species isolated during a period of hospitalization were phenotypically similar to those isolated in samples taken at home. For a second patient, a PCR Mucorale was positive on a sample of bronchoalveolar fluid while air samples taken at his home also revealed also the presence of mucorales. CONCLUSION: The presence of opportunistic fungal species in the air of all the explored homes suggests the need for strengthened preventive measures in the home of immunocompromised patients. It would be interesting to compare the fungi isolated (from patients and from their environment) by genotyping studies aimed at specifying the correspondence existing between fungal species present in the patients' homes and those responsible for IFI in the same patients.