CRISPR/Cas9 genome editing of CCR5 combined with C46 HIV-1 fusion inhibitor for cellular resistant to R5 and X4 tropic HIV-1.

Hematopoietic stem-cell (HSC) transplantation using a donor with a homozygous mutation in the HIV co-receptor CCR5 (CCR5Δ32/Δ32) holds great promise as a cure for HIV-1. Previously, there were three patients that had been reported to be completely cured from HIV infection by this approach. However, finding a naturally suitable Human Leukocyte Antigen (HLA)-matched homozygous CCR5Δ32 donor is very difficult. The prevalence of this allele is only 1% in the Caucasian population. Therefore, additional sources of CCR5Δ32/Δ32 HSCs are required. The Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated (Cas) system is one method to mediate CCR5 knockout in HSCs that has been successfully employed as a gene editing tool in clinical trials. Additional anti-HIV-1 strategies are still required for broad-spectrum inhibition of HIV-1 replication. Here in this study, we combined an additional anti-HIV-1 therapy, which is C46, a cell membrane-anchored HIV-1 fusion inhibitor with the CRISPR/Cas9 mediated knockout CCR5. The combined HIV-1 therapeutic genes were investigated for the potential prevention of both CCR5 (R5)- and CXCR4 (X4)-tropic HIV-1 infections in the MT4CCR5 cell line. The combinatorial CRISPR/Cas9 therapies were superior compared to single method therapy for achieving the HIV-1 cure strategy and shows potential for future applications.

Severe acute respiratory syndrome coronavirus 2 infection rate among pediatric patients with respiratory symptoms.

BACKGROUND: The incidence of coronavirus disease 2019 (COVID-19) in children has been increasing worldwide since the onset of the pandemic. This study examined the risk factors and characteristics of COVID-19 among pediatric patients compared to other respiratory viral infections. METHODS: This was a prospective cross-sectional study. Patients aged 0-18 years presenting with respiratory symptoms from October 2020 to December 2021 were included. Demographic and clinical data were reviewed. RESULTS: In total, 738 pediatric patients were enrolled. Of these, 48.5% had COVID-19, and 41.3% were infected with another respiratory virus. The COVID-19 incidence increased from 0.5% during the original strain outbreak (October 2020 to March 2021) to 56.5% and 73.4% during the alpha (April to June 2021) and delta (July to December 2021) periods, respectively. Children aged 6-18 years, being female, obesity, exposure to household members with COVID-19, and the delta period were risk factors for COVID-19. Being aged 1-5 years, obesity, shortness of breath, productive cough, and chest pain were associated with COVID-19 pneumonia. Children aged 5-18 years, underlying neurological disease, a history of COVID-19 pneumonia, and the delta period were associated with long COVID. CONCLUSIONS: Pediatric COVID-19 patients presenting with respiratory symptoms who are obese or have been exposed to household members with COVID-19 should be tested for COVID-19. COVID-19 patients who are obese, younger than five years old, or who present with shortness of breath, productive cough, or chest pain should be evaluated for pneumonia. COVID-19 patients with a history of COVID-19 pneumonia or underlying neurological disease should receive follow-up for long COVID.

HIV-1 proviral DNA in purified peripheral blood CD34+ stem and progenitor cells in individuals with long-term HAART; paving the way to HIV gene therapy.

Human immunodeficiency virus (HIV)-1 infection is an important public health problem worldwide. After primary HIV-1 infection, transcribed HIV-1 DNA is integrated into the host genome, serving as a reservoir of the virus and hindering a definite cure. Although highly active antiretroviral therapy suppresses active viral replication, resulting in undetectable levels of HIV RNA in the blood, a viral rebound can be detected after a few weeks of treatment interruption. This supports the concept that there is a stable HIV-1 reservoir in people living with HIV-1. Recently, a few individuals with HIV infection were reported to be probably cured by hematopoietic stem transplantation (HSCT). The underlying mechanism for this success involved transfusion of uninfected hematopoietic stem and progenitor cells (HSPCs) from CCR5-mutated donors who were naturally resistant to HIV infection. Thus, gene editing technology to provide HIV-resistant HSPC has promise in the treatment of HIV infections by HSCT. In this study, we aimed to find HIV-infected individuals likely to achieve a definite cure via gene editing HSCT. We screened for total HIV proviral DNA by Alu PCR in peripheral blood mononuclear cells (PBMCs) of 20 HIV-infected individuals with prolonged viral suppression. We assessed the amount of intact proviral DNA via a modified intact proviral DNA assay (IPDA) in purified peripheral CD34+ HSPCs. PBMCs from all 20 individuals were positive for the gag gene in Alu PCR, and peripheral CD34+ HSPCs were IPDA-negative for six individuals. Our results suggested that these six HIV-infected individuals could be candidates for further studies into the ability of gene editing HSCT to lead to a definite HIV cure.

Clinical Outcomes of Human Rhinovirus/Enterovirus Infection in Pediatric Hemopoietic Cell Transplant Patients.

BACKGROUND: Respiratory viral infections are common among pediatric transplant patients, with human rhinovirus (HRV) being the most frequent. In pediatric patients undergoing hemopoietic cell transplant (HCT), infection with HRV has been associated with progression to lower respiratory tract infection (LRTI) and adverse outcomes. We describe the clinical presentation and outcomes of HRV infection in children undergoing HCT. METHODS: Single-center retrospective study. HCT recipients who were positive for HRV/EV (HRV+) or negative for any respiratory virus (VN) by BioFire® FilmArray® panel between October 2014 and December 2017, were included. Primary outcomes were progression to LRTI, ICU admission, all-cause mortality at 3 and 6 months, and respiratory event-related mortality at 6 months. RESULTS: 227 patients (160 allogeneic HCT) were included. Of all patients, 108/227 (47.6%) were HRV+. From all HRV+, 95/108 (88%) were symptomatic and 68/107 (63.6%) of the diagnosis were made pretransplant. The median age of HRV+ was significantly lower than VN patients (5 vs 10 years). Cough and rhinorrhea were more frequently observed in HRV+ (53.7 and 60% vs 19.8 and 22.8%, respectively). No differences were found between both groups pretransplant and overall in rates progression to LRTI, ICU admission, mechanical ventilation, all-cause within 3 and 6 months, and mortality related with respiratory failure. No significant association was found between the severity of respiratory disease and the type of conditioning, type of transplant, or absolute lymphocyte count. CONCLUSIONS: HRV infection is frequently detected in HCT recipients but is not associated with severity of respiratory disease, need for intensive care unit or mortality, including those diagnosed before transplant, suggesting that delaying HCT in this scenario may not be needed. Multicenter larger studies are required to confirm these findings.

Clinical manifestations and outcomes of coronavirus disease 2019 among pediatric liver transplant recipients in the delta and omicron variant pandemic: A retrospective study.

To determine the clinical manifestations and outcomes of the coronavirus disease 2019 (COVID-19) in children who underwent liver transplantation (LT). A retrospective study was conducted at a transplant center in Thailand to include LT recipients aged < 18 years who had been infected with COVID-19. Out of a total of 54 children, there were 31 probable cases (57.4%) diagnosed using an antigen test kit and 23 confirmed cases (42.6%) diagnosed using polymerase chain reaction (14 children) or severe acute respiratory syndrome coronavirus 2 antigen (9 children). Approximately half of the children (25, 46.3%) received the BNT162b2 vaccine before the infection, with 3 and 2 doses in 5 and 18 children, respectively. While some had COVID-19 during the delta pandemic, most (46 children, 85.2%) were infected during the omicron pandemic, of which manifestations included fever (67.4%), cough (50%), and rhinorrhea (47.8%), and symptoms lasted approximately 3 days. None had severe diseases. All patients with mild-to-moderate disease were advised to continue the same immunosuppressive therapy as before the infection. Compared to unvaccinated children or children with one dose of the vaccine, fever was less common in those who received ≥ 2 doses (OR: 0.08; 95%CI: 0.01-0.57, adjusted for age and immunosuppressive types). Favipiravir was prescribed in most patients (90.7%). Only a few children had long COVID-19 or abnormal liver function tests lasting > 1 month (4 children, 7.4%, both). Pediatric LT recipients with COVID-19 during the delta and omicron variant pandemic reported mild symptoms despite undergoing immunosuppressive therapy.

Antimicrobial use for the management of varicella in Thailand: a retrospective observational study.

OBJECTIVE: To describe the clinical characteristics of varicella patients seeking medical consultation and the use of antimicrobials for their management in Thailand in the absence of universal varicella vaccination (UVV). METHODS: A multicenter, retrospective chart review of 260 children and adults with a primary diagnosis of varicella was conducted at one private and three public hospitals in Bangkok, Thailand. Charts of varicella patients (inpatient or outpatient) were randomly selected over a 5-year period. Key outcomes included clinical complications and the use of antibiotics, antivirals, and other medications. RESULTS: Charts of 200 children (mean age 5.7 years, range 0.3-16 years) and 60 adults (mean age 27.9 years, range 18-50 years) were reviewed. Fourteen patients (including 8 children) were hospitalized. Five percent of the children and none of the adults were immunocompromised. At least 1 varicella-related complication was reported by 7.3% (7% of children, 8.3% of adults, p = .778) of all patients, including 57.1% (62.5% of children, 50% of adults) of inpatients (p < .001, compared with outpatients). Skin/soft tissue infection (47.7%) and dehydration (47.4%) were the most common complications. Antivirals (mainly oral acyclovir) were prescribed to 46.5% of patients (31.5% of children, 96.7% of adults, p < .001). Antibiotics were prescribed to 20.8% of patients (19% of children, 26.7% of adults, p = .199). Topical, oral, and intravenous antibiotics were prescribed to 12.3%, 8.5%, and 1.2% of patients, respectively. Antimicrobial prescriptions were higher among adults (p < .001) and immunocompromised patients (p = .025). Apart from antimicrobials, acetaminophen (62.3%) and oral antihistamines (51.5%) were the most prescribed. CONCLUSION: A considerable number of varicella patients, both children and adults, seeking medical consultation in Thai hospitals are prescribed antibiotics and antivirals, with one-fifth of patients being prescribed an antibiotic and almost half prescribed an antiviral. The study may be of interest to policymakers in Thailand and other Asia-Pacific countries considering UVV implementation.

Immunogenicity of Hepatitis B Vaccine in Pediatric Systemic Lupus Erythematosus Patients.

BACKGROUND: Pediatric patients with systemic lupus erythematosus (SLE) are at increased infectious risk caused by underlying immunologic dysregulation and immunosuppressive therapy. Hepatitis B virus (HBV) could be reactivated during the immunosuppressive treatment in patients with past HBV infections. Information on immunogenicity after hepatitis B (HB) immunization and reimmunization are still scarce. METHODS: SLE patients 5-18 years of age who had completed a primary HB immunization were enrolled. Anti-HBs levels at enrollment and after each vaccine dose were determined. Patients with anti-HBs levels < 10 mIU/mL were administered 1 booster dose. After 1 booster dose, patients with negative anti-HBs levels were administered 2 more booster doses. RESULTS: Ninety-three SLE patients were enrolled. The prevalence of seroprotection assessed by anti-HBs > 10 mIU/mL after completion of a primary HB immunization was 25.8% (95% CI: 17.2-34.4). Lupus nephritis was associated with unprotective anti-HBs levels [odds ratio (OR): 4.341; 95% CI: 1.044-18.040]. The anti-HBs seroconversion was 72.3% (95% CI: 61.5-83.0) after 1 booster dose and increased up to 93.4% (95% CI: 86.9-98.4) after 3 booster doses. SLE Disease Activity Index-2000 score ≥ 4 (OR: 4.625; 95% CI: 1.45-14.80) was significantly associated with nonseroconversion after the first booster dose. Hypocomplementemia before the first and second booster doses (OR: 27; 95% CI: 1.26-578.35) was significantly associated with nonseroconversion after 3 booster doses. CONCLUSIONS: All pediatric SLE patients should be evaluated for HBV serological status before immunosuppressive treatment. SLE patients with SLE Disease Activity Index-2000 score > 4 should need 3 booster doses if their anti-HBs level was < 10 mIU/mL.

Pediatric drug utilization evaluation of cefepime and piperacillin/tazobactam.

BACKGROUND: Drug utilization evaluation (DUE) is a systematic, criteria-based assessment of medicine that aims to optimize the appropriateness of antibiotic prescription. This study aimed to evaluate the performance of the DUE on prescriptions of two commonly used antibiotics in a pediatric population, cefepime and piperacillin/tazobactam, in a tertiary care hospital. METHODS: This quasi-experimental study was conducted at the Department of Pediatrics, Ramathibodi Hospital, between March 2020 and August 2021. All hospitalized children aged 1 month to 20 years who received at least one dose of cefepime or piperacillin/tazobactam were enrolled. Before implementing the DUE, cefepime and piperacillin/tazobactam prescriptions were retrospectively evaluated using the DUE criteria. During the 6 month DUE implementation period, physicians voluntarily chose to use DUE to assess the prescriptions' appropriateness. Demographic data, antibiotic use, and clinical data were recorded. RESULTS: There were 304 prescriptions of cefepime and piperacillin/tazobactam, with 108 empirical prescriptions (72 patients) in the DUE group and 158 prescriptions (138 patients) in the non-DUE group. The appropriateness of empirical prescriptions of cefepime and piperacillin/tazobactam was significantly higher in the DUE group (93.5% vs. 83.5%; P = 0.003). Drug utilization evaluation was significantly associated with appropriate empirical prescriptions (adjusted OR 5.32: 95% CI 1.80-15.73; P = 0.003). Prescriptions in critical care wards and urinary tract infections (UTIs) were associated with not fulfilling the DUE criteria for appropriateness. CONCLUSIONS: Drug utilization evaluation could improve the appropriateness of empirical use of cefepime and piperacillin/tazobactam in pediatric patients. Patients in critical care units and with UTIs appeared to be associated with inappropriate empirical treatment.

Handshake stewardship reduces carbapenem prescription in a pediatric critical care setting.

BACKGROUND: Intensive care unit (ICU) settings typically have a high-volume prescription of carbapenems. Antimicrobial stewardship programs (ASPs) aim to promote appropriate antibiotic use. Handshake stewardship (HS) is adapted from ASPs but focuses on direct feedback to physicians who prescribed antibiotics regarding the appropriateness of antibiotic prescription. This study aimed to evaluate the impact and acceptability of HS on carbapenem consumption in pediatric critical care settings. METHODS: This study was conducted over 18 months spanning pre-and post-implementation of HS. Carbapenem prescriptions were automatically discontinued during the pre-implementation period after 72 h if no indications existed. During the post-implementation, HS was performed by direct feedback to ICU physicians regarding the appropriateness of carbapenem prescriptions within 24 h. The primary outcome was the carbapenem consumption rate, defined as days of therapy (DOT)/1,000 patient-ICU days. Secondary outcomes were the acceptability of HS, length of critical care stay (LOCS), 30-day infection-related mortality rate, and the rate of carbapenem-resistant Enterobacteriaceae (CRE). RESULTS: There were 212 carbapenem prescriptions (163 patients) and 174 carbapenem prescriptions (110 patients) in the pre-and post-implementation periods, respectively. Carbapenem consumption decreased significantly from 667 to 369 DOT/1,000 patient-ICU days, with a median difference of 292 DOT/1,000 patient-ICU days (P < 0.001; 95% confidence interval: 175-408) after HS implementation. The acceptability of the HS was 95.4%. The LOCS, 30-day infection-related mortality, and CRE rate were not significantly different between pre-and post-implementation periods. CONCLUSIONS: Handshake stewardship significantly reduced carbapenem prescription in critically ill pediatric patients without negatively affecting patient outcomes.

Association between adenovirus infection and mortality outcome among pediatric patients after hematopoietic stem cell transplant.

BACKGROUND: Adenovirus can cause severe diseases in post-hematopoietic stem cell transplant (HSCT) patients. Because these patients also have many other factors contributing to mortality, it remains controversial whether adenovirus infection itself contributes to increased mortality in these patients. OBJECTIVE: To determine if adenovirus infection contributes to mortality in pediatric post-HSCT patients. METHODS: This retrospective cohort study was performed in post HSCT patients, aged 0-18 years old, admitted at Ramathibodi Hospital from 2016 to 2020. Adenovirus infection was defined as the detection of adenovirus in blood or urine by polymerase chain reaction. Multivariate cox regression was used to identify factors associated with death. RESULTS: The incidence of overall adenovirus infection (viremia or viruria) in this cohort was 20.8% (26 out of 125 enrolled patients). From the multivariate cox regression analysis, overall adenovirus infection was not significantly associated with death (hazard ratio [HR]: 2.41; 95% confidence interval [CI]: 0.96-6.06; p = .060). However, presence of viremia (HR: 3.90; 95% CI: 1.40-10.86; p = .009), having maximal serum viral load > 10 000 copies/ml (HR: 3.70; 95% CI: 1.20-11.38; p = .023), presence of end-organ diseases (HR: 3.44; 95% CI: 1.18-10.01; p = .023) were associated with mortality. Underlying diseases requiring long-term immunosuppressive drugs before HSCT, invasive fungal disease, invasive bacterial infection, cytomegalovirus infection, and longer engraftment time were also associated with mortality. CONCLUSION: Overall adenovirus infection does not appear to play a significant role in mortality in pediatric post-HSCT patients. However, more invasive forms of adenovirus infection were associated with mortality in these patients.

Viral Tropism in Human Immunodeficiency Virus Type 1-Infected Children and Adolescents in Thailand.

BACKGROUND: Maraviroc, a C-C chemokine receptor 5 (CCR5) antagonist, has been used as an alternative antiretroviral drug in treatment-experienced adults and children infected by CCR5-tropic human immunodeficiency virus type 1 (HIV-1) isolates. Prior to widespread use of this drug, rates of HIV-1 coreceptor tropism and factors associated with coreceptor tropism had to be determined. METHODS: HIV-1-infected individuals aged <20 years with HIV-1 viral loads >1000 RNA copies/mL who were treatment-experienced or treatment-naive were enrolled. HIV-1 coreceptor tropism was determined using a genotypic test in which V3 sequences were analyzed with GENO2PHENO version 2.5 and a false discovery rate of 5%. RESULTS: Fifty-two HIV-1-infected patients were recruited. The median age of participants was 14.9 years (interquartile range [IQR], 8.9-16.8 years). The median CD4 cell count was 396.0 cells/µL (IQR, 72.0-630.3 cells/µL). The median HIV-1 viral load was 43 339 RNA copies/mL (IQR, 8874-197 055 copies/mL). Thirty-nine patients (75%) were treatment-experienced. The most prevalent HIV-1 subtype in this population was CRF01_AE (36 patients, 69.2%). Based on analyses of V3 loop sequences, 5 of 13 treatment-naive patients (38.5%) and 11 of 39 treatment-experienced patients (28.2%) were infected by R5 viruses, while 7 of 13 treatment-naive patients (53.8%) and 19 of 39 treatment-experienced patients (48.7%) were infected by X4 viruses. The only factor associated with the presence of X4 viruses was HIV-1 subtype CRF01_AE. CONCLUSIONS: X4-tropic viruses are associated with the CRF01_AE subtype. Hence, testing of HIV tropism should be performed before treatment with CCR5 inhibitors in children in areas where CRF01_AE predominates.

Immune responses to hepatitis B vaccination after hematopoietic stem cell transplantation in pediatric and young adult patients.

BACKGROUND: Hematopoietic stem cell transplantation (HSCT) recipients require hepatitis B (HBV) revaccination. Hepatitis B surface antibody (anti-HBs) seroconversion rates after revaccination range from 64% to 79% in these patients. The seroconversion rate and factors associated with non-seroconversion have not been clearly elucidated in pediatric and young adult recipients after HSCT. OBJECTIVES: To evaluate anti-HBs seroconversion rates in pediatric and young adult patients revaccinated after HSCT, and to identify factors associated with non-seroconversion. METHOD: The current study was prospective and cross-sectional. Post-HSCT recipients aged ≤25 years who had completed a course of three HBV revaccinations were recruited, and their anti-HBs titers were assessed. Non-seroconverted patients were administered a fourth vaccination. Those who subsequently remained seronegative were administered two additional vaccinations. Those who remained seronegative after all six vaccinations were defined as non-responders. RESULTS: A total of 118 patients were enrolled. The HBV-containing vaccines used included DTaP-IPV-HBV-Hib, DTwP-HBV-Hib, and monovalent vaccines. The anti-HBs seroconversion rate after three revaccinations was 82% (95% confidence interval [CI], 73.7-89.2). One patient (0.8%) was classified as non-responder. Factors associated with non-seroconversion after three revaccinations included cytomegalovirus (CMV) reactivation (odds ratio [OR] 10.63, 95% CI 1.16-97.00), anti-HBs seronegativity before HSCT (OR 7.01, 95% CI 1.55-31.78) and three DTwP-HBV-Hib revaccinations (OR 11.71, 95% CI 1.43-96.26). CONCLUSION: In the current study the anti-HBs seroconversion rate after three HBV revaccinations was excellent. CMV reactivation, anti-HBs seronegativity before HSCT, and three DTwP-HBV-Hib revaccinations were associated with non-seroconversion, but the non-responder rate was low.

Erratum to: An Outbreak of Brucellosis: An Adult and Pediatric Case Series.

[This corrects the article DOI: 10.1093/ofid/ofz384.][This corrects the article DOI: 10.1093/ofid/ofz384.].

An Outbreak of Brucellosis: An Adult and Pediatric Case Series.

Background: Brucellosis is recognized as a neglected zoonotic disease and a major public health threat. The purpose of this study was to characterize epidemiological risk factors and healthcare utilization and compare clinical aspects of disease among adult and pediatric cases in North Texas. Methods: A retrospective chart review of electronic medical records was completed at 3 large tertiary centers-Parkland Health and Hospital System, Clements University Hospital, and Children's Medical Center-between January 1, 2007 and June 1, 2017. Demographic, clinical, and laboratory variables were collected. Cases were defined as confirmed or probable. Results: Twenty-eight cases of brucellosis were identified: 26 confirmed (9 children, 17 adults) and 2 probable cases (1 child, 1 adult). Half (n = 14) were diagnosed in 2016 during an outbreak in Dallas County. Risk factors associated with infection were consumption of unpasteurized cheese (71%), recent travel (54%), close contact to a confirmed human brucellosis case (36%), and exposure to animals (11%). Median days of symptoms was 10 and 16 for children and adults, respectively. The majority (79%) of patients visited the emergency department before diagnosis and 93% were hospitalized. Fever was the most common symptom in children (80%) and adults (100%). Hepatitis (75% of children) and anemia (82% of adults) were the most common laboratory abnormalities. The most common complication in children was splenic lesions (40%), and the most common complication in adults was hepato/splenomegaly (39%). Conclusions: The diagnosis of Brucella infection requires a high index of suspicion and should be considered in patients presenting with a febrile illness and a compatible exposure history.

Screening Mycobacterium tuberculosis Secreted Proteins Identifies Mpt64 as a Eukaryotic Membrane-Binding Bacterial Effector.

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis, is one of the most successful human pathogens. One reason for its success is that Mtb can reside within host macrophages, a cell type that normally functions to phagocytose and destroy infectious bacteria. However, Mtb is able to evade macrophage defenses in order to survive for prolonged periods of time. Many intracellular pathogens secrete virulence factors targeting host membranes and organelles to remodel their intracellular environmental niche. We hypothesized that Mtb secreted proteins that target host membranes are vital for Mtb to adapt to and manipulate the host environment for survival. Thus, we characterized 200 secreted proteins from Mtb for their ability to associate with eukaryotic membranes using a unique temperature-sensitive yeast screen and to manipulate host trafficking pathways using a modified inducible secretion screen. We identified five Mtb secreted proteins that both associated with eukaryotic membranes and altered the host secretory pathway. One of these secreted proteins, Mpt64, localized to the endoplasmic reticulum during Mtb infection of murine and human macrophages and impaired the unfolded protein response in macrophages. These data highlight the importance of secreted proteins in Mtb pathogenesis and provide a basis for further investigation into their molecular mechanisms.IMPORTANCE Advances have been made to identify secreted proteins of Mycobacterium tuberculosis during animal infections. These data, combined with transposon screens identifying genes important for M. tuberculosis virulence, have generated a vast resource of potential M. tuberculosis virulence proteins. However, the function of many of these proteins in M. tuberculosis pathogenesis remains elusive. We have integrated three cell biological screens to characterize nearly 200 M. tuberculosis secreted proteins for eukaryotic membrane binding, host subcellular localization, and interactions with host vesicular trafficking. In addition, we observed the localization of one secreted protein, Mpt64, to the endoplasmic reticulum (ER) during M. tuberculosis infection of macrophages. Interestingly, although Mpt64 is exported by the Sec pathway, its delivery into host cells was dependent upon the action of the type VII secretion system. Finally, we observed that Mpt64 impairs the ER-mediated unfolded protein response in macrophages.

Pediatric extended spectrum ß-lactamase infection: Community-acquired infection and treatment options.

BACKGROUND: Infection caused by extended spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae in pediatric patients has been increasing and spreading to the community, compromising the options for effective antibiotics. This retrospective study was conducted to identify which antibiotics ESBL-producing Enterobacteriaceae remain susceptible to. In addition, the prevalence of community-acquired infection caused by these organisms, and the possibility of association between these organisms and septic shock, were explored. METHODS: Antibiotic susceptibility of ESBL-producing and non-ESBL-producing Escherichia coli and Klebsiella pneumoniae strains isolated from pediatric patients were reviewed to determine the rates of susceptibility to various antibiotics. A chart review was performed to clarify the prevalence of community-acquired infection and the severity. RESULTS: Of 849 strains analyzed, 40% were ESBL positive. Apart from cephalosporins, ESBL-producing strains were also less likely to be susceptible to other antibiotics, such as quinolones, gentamicin, netilmicin, and cotrimoxazole, more than 90% of which were still susceptible to amikacin, carbapenems, colistin, and tigecycline. Around 20% of community-acquired infections in the present study were caused by ESBL-producing strains. ESBL-producing strains found in the community were more likely to be susceptible to gentamicin, netilmicin, and cefepime than those found in hospital. Infection caused by ESBL-producing strains was not significantly associated with septic shock. CONCLUSION: The increase in infection caused by ESBL-producing Enterobacteriaceae limits the availability of effective antibiotics. Given that carbapenems are necessary for treating serious infections, amikacin, cefepime, and piperacillin/tazobactam are possible options for consolidative therapy or for non-serious infection.

Infectious complications in children with acute lymphoblastic leukemia treated in low-middle-income countries.

Infections are the most important cause of morbidity and mortality in children treated for acute lymphoblastic leukemia (ALL). The rates of infection-associated mortality are up to 10-times higher in low- and middle-income countries (LMIC) than in high-income countries. The prevention, early recognition and management of infectious complications is especially challenging in LMIC because of disease and poverty-related factors, as well as the shortage of trained personnel, supplies, diagnostic tools and adequate organizational infrastructure. Children in LMIC with ALL, who are frequently underweight, are at increased risk of community-acquired pathogens, nosocomial multidrug-resistant pathogens and opportunistic microorganisms. This review summarizes the challenges of managing the major categories of infections in children receiving treatment for ALL and provides updated practical recommendations for preventing and managing these infections in LMIC.

Modulation of immune responses during HIV-malaria co-infection in pregnancy.

Infection with either HIV or malaria during pregnancy often results in adverse outcomes for mother and child. Co-infection further increases the risks of these events, which include maternal anemia and babies with low birth weight. The immunological bases for the increased susceptibility of HIV-infected mothers to malaria and for the effect of co-infection on mother-to-child transmission of HIV are areas of major importance in public health. In this article, we review current data about humoral and cellular responses to HIV-placental-malaria co-infection and present an immunological hypothesis to explain the epidemiological findings.

Immunohistological characterization of macrophage migration inhibitory factor expression in Plasmodium falciparum-infected placentas.

Previously, we have shown that macrophage migration inhibitory factor (MIF) was highly elevated in the placental intervillous blood (IVB) of Plasmodium falciparum-infected women. Here, we compared the expression of MIF in placental tissues obtained from P. falciparum-infected and -uninfected women. Immunoperoxidase staining showed a consistent pattern of MIF expression in syncytiotrophoblasts, extravillous trophoblasts, IVB mononuclear cells, and amniotic epithelial cells, irrespective of their malaria infection status. Cytotrophoblast, villous stroma, and Hofbauer cells showed focal staining. Only amniotic epithelial and IVB mononuclear cells from P. falciparum-infected placentas exhibited significantly higher level of MIF expression than uninfected placentas. Stimulation of syncytilized human trophoblast BeWo cells with P. falciparum-infected erythrocytes that were selected to bind these cells resulted in significant increases in MIF secretion, whereas control erythrocytes, lipopolysaccharides, and synthetic beta-hematin had minimal effect. These findings suggest that placental malaria modulates MIF expression in different placental compartments.

Hemozoin differentially regulates proinflammatory cytokine production in human immunodeficiency virus-seropositive and -seronegative women with placental malaria.

Pregnant women are at an increased risk for malarial infection. Plasmodium falciparum accumulates in the placenta and is associated with dysregulated immune function and poor birth outcomes. Malarial pigment (hemozoin) also accumulates in the placenta and may modulate local immune function. In this study, the impact of hemozoin on cytokine production by intervillous blood mononuclear cells from malaria-infected placentas was investigated. There was a dose-dependent, suppressive effect of hemozoin on production of gamma interferon (IFN-gamma), with less of an effect on tumor necrosis factor alpha (TNF-alpha) and interleukin-10, in human immunodeficiency virus-seronegative (HIV(-)) women. In contrast, IFN-gamma and TNF-alpha production tended to increase in HIV-seropositive women with increasing hemozoin levels. Production patterns of cytokines, especially IFN-gamma in HIV(-) women, followed different trends as a function of parasite density and hemozoin level. The findings suggest that the influences of hemozoin accumulation and high-density parasitemia on placental cytokine production are not equivalent and may involve different mechanisms, all of which may operate differently in the context of HIV infection. Cytokine production dysregulated by accumulation of hemozoin or high-density parasitemia may induce pathology and impair protective immunity in HIV-infected and -uninfected women.