Clinical spectrum of serious bacterial infections among splenectomized patients with hemoglobinopathies in Israel: a 37-year follow-up study

Survival and causes of death in patients with alpha and beta-thalassemia in Northern Thailand

BACKGROUND

Thalassemia is the most prevalent hereditary anaemia worldwide. Severe forms of thalassemia can lead to reduced life expectancy due to disease-related complications.

OBJECTIVES

To investigate the survival of thalassemia patients across varying disease severity, causes of death and related clinical factors.

PATIENTS AND METHODS

We conducted a retrospective review of thalassemia patients who received medical care at Chiang Mai University Hospital. The analysis focused on survival outcomes, and potential associations between clinical factors and patient survival.

RESULTS

A total of 789 patients were included in our study cohort. Among them, 38.1% had Hb H disease, 35.4% had Hb E/beta-thalassemia and 26.5% had beta-thalassemia major. Half of the patients (50.1%) required regular transfusions. Sixty-five patients (8.2%) had deceased. The predominant causes of mortality were infection-related (36.9%) and cardiac complications (27.7%). Transfusion-dependent thalassemia (TDT) (adjusted HR 3.68, 95% CI 1.39-9.72, p = 0.008) and a mean serum ferritin level ≥3000 ng/mL (adjusted HR 4.18, 95% CI 2.20-7.92, p < 0.001) were independently associated with poorer survival.

CONCLUSIONS

Our study highlights the primary contributors to mortality in patients with thalassemia as infection-related issues and cardiac complications. It also underscores the significant impact of TDT and elevated serum ferritin levels on the survival of thalassemia patients.

Campylobacter gastroenteritis and bacteremia in an asplenic patient with a recent history of Yersinia Enterocolitis: Case report and literature review

In this case report, we present a patient with a history of splenectomy and two recent hospital admissions for severe gastroenteritis with sepsis. The first hospital admission was for Yersinia enterocolitica and the second admission was for Campylobacter fetus gastroenteritis with bacteremia. During both admissions, the patient was treated with a prolonged course of antibiotics and later discharged with full recovery. In our review, we address the risk of enterocolitis in splenectomized patients.

Associations of maternal and placental extracellular vesicle miRNA with preeclampsia

Introduction: Gestational vascular complications (GVCs), including gestational hypertension and preeclampsia, are leading causes of maternal morbidity and mortality. Elevated levels of extracellular vesicles (EVs), in GVC have been linked to vascular injury. This study aims to characterize placental and circulating EV miRNA in GVCs, and explores the involvement of EV-miRNA in GVC, and whether they may be used to distinguish between placental and maternal pathologies. Methods: Blood samples were obtained from 15 non-pregnant (NP), 18 healthy-pregnant (HP), and 23 women with GVC during the third trimester. Placental sections were obtained after caesarian section. Platelet-poor-plasma (PPP) and EV pellets were characterized: EV size/concentration, protein content and miRNA expression were measured by nanoparticle tracking analysis, western blot, nano-string technology and RT-PCR. The effects of EVs on trophoblasts and EC miRNA expression were evaluated. Results: Higher EVs concentrations were observed in HP-PPP and GVC-PPP (p < 0.0001) compared to the NP-PPP. The concentration of large EVs (>100 nm) was higher in PPP and EV pellets of HP and GVC compared to the NP group. EV pellets of pregnant women demonstrated lower expression of exosomal markers CD63/CD81 compared to NP-EVs. GVC-EVs expressed more human placental lactogen (hPL) hormone than HP-EVs, reflecting their placental origin. Screening of miRNAs in EV pellets and in PPP identified certain miRNAs that were highly expressed only in EVs pellets of the HP (13%) and GVC groups (15%), but not in the NP group. Differences were detected in the expression of hsa-miR-16-5p, hsa-miR-210, and hsa-miR-29b-3p. The expression of hsa-miR-16-5p and hsa-miR-210 was low in EV pellets obtained from NP, higher in HP-EVs, and significantly lower in GVC-EVs. Except for hsa-miR-29b-3p, which was upregulated in GVC, no significant differences were found in the levels of other miRNAs in placental sections. Exposure to GVC-EVs resulted in higher expression of hsa-miR-29b-3p compared to cells exposed to HP-EVs in villous trophoblasts, but not in EC. Conclusion: Expression of hsa-miR-16-5p and hsa-miR-210 reflects maternal pathophysiological status, while hsa-miR-29b-3p reflects placental status. These findings suggest that EV-miRNA are involved in GVC, and that they may be used to distinguish between pathologies of placental and maternal origins in preeclampsia.

Extracellular Vesicle MicroRNA That Are Involved in β-Thalassemia Complications

Beta thalassemia major (βT) is a hereditary anemia characterized by transfusion-dependency, lifelong requirement of chelation, and organ dysfunction. MicroRNA (miRNA) can be packed into extracellular vesicles (EVs) that carry them to target cells. We explored EV-miRNA in βT and their pathophysiologic role. Circulating EVs were isolated from 35 βT-patients and 15 controls. EV miRNA was evaluated by nano-string technology and real-time quantitative polymerase chain reaction (RT-qPCR). We explored effects of EVs on cell culture proliferation, apoptosis, and signal transduction. Higher amounts of small EV (exosomes) were found in patients than in controls. The expression of 21 miRNA was > two-fold higher, and of 17 miRNA < three-fold lower in βT-EVs than control-EVs. RT-qPCR confirmed differential expression of six miRNAs in βT, particularly miR-144-3p, a regulator of erythropoiesis. Exposure of endothelial, liver Huh7, and pancreatic 1.1B4 cells to βT-EVs significantly reduced cell viability and increased cell apoptosis. βT-EV-induced endothelial cell apoptosis involved the MAPK/JNK signal-transduction pathway. In contrast, splenectomized βT-EVs induced proliferation of bone marrow mesenchymal stem cells (BM-MSC). In summary, the miR-144-3p was strongly increased; βT-EVs induced apoptosis and decreased endothelial, pancreatic, and liver cell survival while supporting BM-MSC proliferation. These mechanisms may contribute to βT organ dysfunction and complications.

Higher Hospitalization Rate for Lower Airway Infection in Transfusion-Naïve Thalassemia Children

Few studies have addressed the risk of infection in transfusion-naïve thalassemia patients. We aimed to investigate whether transfusion-naïve thalassemia population has higher hospitalization rates for lower airway infection-related diseases than non-thalassemia population in children. A nationwide population-based retrospective cohort study was conducted using detailed medical records of the Taiwan National Health Insurance Research Database. Transfusion-naïve thalassemia patients were compared with a matched cohort at a ratio of 1:4. Data of the selected patients were adjusted for age, sex, and related comorbidities. We recorded the frequency of admissions or outpatient clinic visits for patients with a diagnosis of pneumonia or acute bronchitis/bronchiolitis. Based on our results, the hospitalization rates and incidence rate ratios of bronchitis/bronchiolitis and pneumonia for transfusion-naïve thalassemia children were all higher than those for non-thalassemia controls. Therefore, we conclude that transfusion-naïve thalassemia children are more likely to experience lower airway infections and have a higher probability of hospitalization for these conditions.

Extracellular Vesicle Characteristics in β-thalassemia as Potential Biomarkers for Spleen Functional Status and Ineffective Erythropoiesis

β-thalassemia major (β-TM) is a therapeutically challenging chronic disease in which ineffective erythropoiesis is a main pathophysiological factor. Extracellular vesicles (EVs) are membrane-enclosed vesicles released by cells into biological fluids; they are involved in intercellular communication and in multiple physiological and pathological processes. The chaperone heat-shock protein 70 (HSP70), which is released from cells via EVs, aggravates ineffective erythropoiesis in β-TM. We propose that β-TM EVs may show specific signatures, reflecting disease mechanisms, stages and severity. Our study aims were to define EV profiles in β-TM patients, investigate the influence of hypersplenism and splenectomy on EV features, and explore the association of circulating EVs with ineffective erythropoiesis and iron-overload parameters. We characterized circulating EVs in 35 transfusion-dependent β-thalassemia patients and 35 controls using several techniques. Nanoparticle-tracking analysis revealed increased EV concentration in patients vs. controls (P = 0.0036), with smaller EV counts and sizes in patients with hypersplenism. Flow cytometry analysis showed lower levels of RBC and monocyte EVs in patients vs. controls. RBC-EV levels correlated with patient hematocrit, reflecting degree of anemia. The procoagulant potential of the EVs evaluated by flow cytometry revealed lower levels of endothelial protein C receptor-labeled EVs in patients vs. controls, and increased tissue factor-to-tissue factor pathway inhibitor-labeled EV ratio in splenectomized patients, suggesting a hypercoagulable state. Protein content, evaluated in EV pellets, showed increased levels of HSP70 in patients (P = 0.0018), inversely correlated with transfusion requirement and hemoglobin levels, and positively correlated with reticulocyte, erythropoietin and lactate dehydrogenase levels. This first description of EVs in patients with hypersplenism reveals the spleen’s importance in EV physiology and clearance. Circulating EV-HSP70 levels were associated with markers of ineffective erythropoiesis, hemolysis and hematological disease severity. EV analysis in β-TM—reflecting spleen status, hypercoagulability state and ineffective erythropoiesis—may serve as a biomarker of disease dynamics, supporting both anticipation of the risk of complications and optimizing treatment.

Characterization and Antimicrobial Susceptibility Profile of Bacteraemia Causing Pathogens Isolated from Febrile Children with and without Sickle Cell Disease in Kano, Nigeria

Background and Objectives

Bacterial infection in sickle cell anaemic patients is a major cause of mortality and requires proper treatment with appropriate antibiotics. However, continue defiant of these infections causing pathogens to many antibiotics and inadequate screening methods in overburden health care facilities such as our in Kano, Nigeria necessitates the conduct of this study. A research was therefore conducted to isolate, characterize and test for antimicrobial susceptibility of bacteraemia-causing pathogens from febrile children with and without sickle cell disease in Kano, Nigeria.

Method

A total of 225 venous blood samples from suspected sickle cell anaemic children attending three selected hospitals within Kano metropolis were collected and screened for sickle cell disease, followed by blood culture using automated blood culture system. The bacteria isolated from confirmed febrile SCD and non-SCD children were characterized using microscopic, biochemical and serological techniques. Their susceptibility to commonly used antibiotics was tested using disc diffusion method.

Results

Of the 225 blood specimens screened, 68 (30.22%) were SCD positive, with the highest percentage (16%) among subjects within 1–2 years of age. A total of 11 genera of bacteria were isolated from both SCD and non SCD positive bloods, with Salmonella typhi having highest occurring rate in SCD positive children 27 (39.71%), followed by Streptococcus pneumoniae 10(14.71%), Salmonella Group B 9(13.24%), Staphylococcus aureus 4 (5.88%), and Escherichia coli 3 (4.41%). Majority of the isolates from SCD children 59 (86.76%) were highly susceptible to ciprofloxacin followed by cefuroxime 45 (66.18%), gentamicin 38 (55.88%), ceftriaxone 30 (44.12%), augmentin 39 (57.35%), ampicillin 25 (36.77%) and co-trimoxazole (22.06%).

Conclusion

Bacteraemia in SCD confirmed children in the three hospitals are caused by a combination of 11 genera of bacteria. The lesser rate of bacteraemia was found in non-SCD children. Resistance to commonly used antibiotics is on increase, but treatment with ciprofloxacin and some 3^rd generation cephalosporin are still promising.

Epidemiologic study of major complications in adolescent and adult patients with thalassemia in Northeastern Thailand: the E-SAAN study phase I

INTRODUCTION

Thalassemia-related complications are one of the main factors that increase morbidity and mortality in aging patients with thalassemia. This study was aimed to report the prevalence and clinical risk factors for the complications in thalassemia.

METHODS

A multi-center prospective cohort study was conducted in patients with thalassemia aged ≥10 years old. Thalassemia-related complications were heart failure, pulmonary hypertension, extramedullary hematopoiesis, endocrine disorders, infections, thrombosis and leg ulcers. The clinical parameters significantly associated with the complications were analyzed by logistic regression methods.

RESULTS

The prevalence of thalassemia-related complications was 60.5% in patients with transfusion-dependent thalassemia (TDT) and 43% in patients with non-transfusion-dependent thalassemia (NTDT). Splenectomy was statistically associated with complications in both TDT and NTDT patients (adjusted odds ratio (AOR) = 7.4, p-value = 0.0001 and AOR = 2.6, p-value = 0.001). Age ≥50 years old (AOR = 2.9, p-value = 0.04) and female gender (AOR = 0.5, p-value = 0.03) were statistically associated with the complications in patients with NTDT.

CONCLUSION

Nearly half of the patients in this cohort had disease-related complications. Splenectomy and advanced age were important factors for complication involvement. Early screening for the complications may reduce the morbidity and mortality in patients with thalassemia.

Bacterial Infections Following Splenectomy for Malignant and Nonmalignant Hematologic Diseases

Splenectomy, while often necessary in otherwise healthy patients after major trauma, finds its primary indication for patients with underlying malignant or nonmalignant hematologic diseases. Indications of splenectomy for hematologic diseases have been reducing in the last few years, due to improved diagnostic and therapeutic tools. In high-income countries, there is a clear decrease over calendar time in the incidence of all indication splenectomy except nonmalignant hematologic diseases. However, splenectomy, even if with different modalities including laparoscopic splenectomy and partial splenectomy, continue to be a current surgical practice both in nonmalignant hematologic diseases, such as Immune Thrombocytopenic Purpura (ITP), Autoimmune Hemolytic Anemia (AIHA), Congenital Hemolytic Anemia such as Spherocytosis, Sickle Cell Anemia and Thalassemia and Malignant Hematological Disease, such as lymphoma. Today millions of people in the world are splenectomized. Splenectomy, independently of its cause, induces an early and late increase in the incidence of venous thromboembolism and infections. Infections remain the most dangerous complication of splenectomy. After splenectomy, the levels of antibody are preserved but there is a loss of memory B cells against pneumococcus and tetanus, and the loss of marginal zone monocytes deputed to immunological defense from capsulated bacteria. Commonly, the infections strictly correlated to the absence of the spleen or a decreased or absent splenic function are due to encapsulated bacteria that are the most virulent pathogens in this set of patients. Vaccination with polysaccharide and conjugate vaccines again Streptococcus pneumoniae, Haemophilus influenzae, and Neisseria meningitidis should be performed before the splenectomy. This practice reduces but does not eliminate the occurrence of overwhelming infections due to capsulated bacteria. At present, most of infections found in splenectomized patients are due to Gram-negative (G-) bacteria. The underlying disease is the most important factor in determining the frequency and severity of infections. So, splenectomy for malignant diseases has the major risk of infections.

Severe bacterial infections in patients with non-transfusion-dependent thalassemia: prevalence and clinical risk factors

INTRODUCTION

Bacterial infection is one of the major causes of death in patients with thalassemia. Clinical predictive factors for severe bacterial infection were evaluated in patients with non-transfusion-dependent thalassemia (NTDT).

METHODS

A retrospective study was conducted of patients with NTDT aged ≥ 10 years at Srinagarind Hospital, Khon Kaen University, Thailand. Clinical characteristics and potential clinical risk factors for bacterial infection were collected. Risk factors for bacterial infection were evaluated by multivariate logistic regression analysis.

RESULTS

A severe bacterial infection was found in 11 of the total 211 patients with NTDT (5.2%). None of the clinical factors assessed was shown to be statistically associated with severe bacterial infection in patients with NTDT. However, three factors were demonstrated to be potential predictive factors for severe bacterial infection: time after splenectomy >10 years, deferoxamine therapy, and serum ferritin >1000 ng/ml. None of the patients died from infection.

CONCLUSION

The prevalence of bacterial infection in patients with NTDT was found to be moderate. Time after splenectomy >10 years, deferoxamine therapy, and iron overload may be clinical risk factors for severe bacterial infection in patients with NTDT. Bacterial infection should be recognized in splenectomized patients with NTDT, particularly those who have an iron overload.

Thalassaemia major and infectious risk: High Mobility Group Box-1 represents a novel diagnostic and prognostic biomarker

High mobility group box -1 (HMGB1) represents a common causal agent for various types of diseases, including infective pathologies. This study aimed to investigate the role of HMGB1 in β-thalassemia major (TM) by evaluating its diagnostic and prognostic role. Fifty-one TM patients and 30 healthy subjects (HS) were enrolled. Receiver operating characteristics (ROC) analysis was employed to calculate the area under the curve (AUC) for HMGB1 to determine the best cut-off values capable of identifying infectious episodes. Adjusted risk estimates for infective events were calculated using univariate followed by multivariate Cox proportional hazard regression analysis. Serum HMGB1 levels were higher in TM patients than in HS (14·6 ± 8·7 vs. 2·08 ± 0·9 ng/ml, P < 0·0001). Patients who underwent splenectomy were characterized by lower levels of HMGB1, when compared with patients with an intact spleen (10·2 ± 8 vs. 19·1 ± 7 ng/ml, P = 0·004). ROC analyses revealed an AUC for serum HMGB1 of 0·801, with a sensitivity and specificity of 92·3% and 68·2% to detect an infectious episode. Low HMGB1 levels predicted high risk of infective events (HR: 0·81; P = 0·006). HMGB1 represents a prognostic marker for TM patients and a predictive factor for infectious events.

Fatal sepsis in a child with thalassemia major due to Serratia marcescens

One of the most important causes of mortality in thalassemic patients is infectious disease. Thalassemic patients develop severe invasive infection caused by microorganisms that are rare in healthy individuals. We describe the case of a 13-year-old splenectomized boy who presented with septic shock and who died 36 h after admission, despite broad-spectrum antibiotics and aggressive supportive care. Serratia marcescens was isolated from cultures of blood and tracheal aspirate. It is known that rare microorganisms will cause severe community-acquired infection in splenectomized patients with thalassemia major.

Intraperitoneal prophylaxis with CpG oligodeoxynucleotides protects neutropenic mice against intracerebral Escherichia coli K1 infection

Background

Prophylaxis with unmethylated cytosine phosphate guanidine (CpG) oligodeoxynucleotides (ODN) protects against several systemic experimental infections. Escherichia coli is a major cause of Gram-negative neonatal bacterial meningitis and also causes meningitis and meningoencephalitis in older and immunocompromised patients.

Methods

Wild-type (wt) and Toll-like receptor 9 (TLR9)-deficient mice were rendered neutropenic by intraperitoneal administration of the anti-Ly-6G monoclonal antibody. Immunocompetent and neutropenic mice received intraperitoneal CpG ODN or vehicle 72 h prior to induction of E. coli K1 meningoencephalitis.

Results

Pre-treatment with CpG ODN significantly increased survival of neutropenic wt mice from 33% to 75% (P = 0.0003) but did not protect neutropenic TLR9^-/- mice. The protective effect of CpG ODN was associated with an enhanced production of interleukin (IL)-12/IL-23p40 with sustained increased levels in serum and spleen at least for 17 days after conditioning compared to buffer-treated animals. CpG-treated neutropenic wt mice showed reduced bacterial concentrations and increased recruitment of Ly6C^highCCR2⁺ monocytes in brain and spleen 42 h after infection. The levels of macrophage inflammatory protein 1α (MIP-1α) and interferon gamma (IFN-γ) in spleen were higher 42 h after infection in CpG-treated compared to buffer-treated neutropenic animals. In immunocompetent mice, prophylaxis with CpG ODN did not significantly increase survival compared to the buffer group (60% vs. 45%, P = 0.2).

Conclusions

These findings suggest that systemic administration of CpG ODN may help to prevent bacterial CNS infections in immunocompromised individuals.

Demographic and clinical characteristics of Campylobacter bacteremia in children with and without predisposing factors

BACKGROUND

Campylobacter, a common cause of childhood gastroenteritis, rarely causes bacteremia, which is reported mainly in immune-compromised children. Our aim was to compare demographic and clinical characteristics of childhood campylobacter bacteremia (CB) between children with and without risk factors for CB.

METHODS

A retrospective, population-based study, conducted between 1989 and 2010. Risk factors were defined as immunodeficiency, malignancy, extreme prematurity or chronic diseases with malnutrition.

RESULTS

Seventy-six CB episodes (1 per child/month) were identified in 14 children with risk factors (30 episodes) and 46 children without risk factors (46 episodes). Children with risk factors were older (mean age 120.0±72.8 vs. 16.2±27.6 months) with higher proportion of males (90.0% vs. 60.9%), less gastrointestinal symptoms (43.3% vs. 69.9%) and higher hospitalization rates (96.7% vs. 69.6%) compared with children without risk factors. Campylobacter jejuni and Campylobacter coli (46/47 of identified species) were the most common species in both groups. Positive campylobacter stool cultures were found only in children without risk factors (0% vs. 38.5%). No mortality cases were observed. All isolates tested for antibiotic susceptibility were sensitive to macrolides and carbapenems.

CONCLUSIONS

Childhood CB is rare in southern Israel. The disease manifests as a single gastroenteritis complication in a previously healthy young child or as recurrent episodes in an older, immune-compromised child, usually without gastrointestinal symptoms. This disparity may reflect pathogenesis differences, with disease in the immune-competent being dependent on pathogen virulence, whereas disease in the immune-compromised being host dependent. Disease outcome is usually favorable, and macrolides remain the antibiotic treatment of choice.

The Austrian syndrome: a case report and review of the literature

A 61-year-old man presented with fever and altered mental status. He was intubated for respiratory distress and was found to have multilobar pneumonia for which antibiotic therapy was instituted. However, his mental status continued to deteriorate despite appropriate antibiotic therapy for his pneumonia. The results from lumar puncture revealed meningitis and endocarditis was evident on a trans-esophageal echocardiogram. His blood and respiratory cultures grew Streptococcus pneumoniae. The patient was diagnosed with Austrian syndrome. After appropriate changes to his antibiotic regimen and an aortic valve replacement, he recovered and was discharged.