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Flagellum-mediated motility is essential to Pseudomonas aeruginosa (P. aeruginosa) virulence. Antibody against flagellin reduces motility and inhibits the spread of the bacteria from the infection site. The standard soft-agar assay to demonstrate anti-flagella motility inhibition requires long incubation times, is difficult to interpret, and requires large amounts of antibody. We have developed a time-lapse video microscopy method to analyze anti-flagellin P. aeruginosa motility inhibition that has several advantages over the soft agar assay. Antisera from mice immunized with flagellin type A or B were incubated with Green Fluorescent Protein (GFP)-expressing P. aeruginosa strain PAO1 (FlaB+) and GFP-expressing P. aeruginosa strain PAK (FlaA+). We analyzed the motion of the bacteria in video taken in ten second time intervals. An easily measurable decrease in bacterial locomotion was observed microscopically within minutes after the addition of small volumes of flagellin antiserum. From data analysis, we were able to quantify the efficacy of anti-flagellin antibodies in the test serum that decreased P. aeruginosa motility. This new video microscopy method to assess functional activity of anti-flagellin antibodies required less serum, less time, and had more robust and reproducible endpoints than the standard soft agar motility inhibition assay.
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Anticuerpos Antibacterianos , Flagelos , Flagelina , Sueros Inmunes , Microscopía por Video , Pseudomonas aeruginosa , Flagelina/inmunología , Pseudomonas aeruginosa/inmunología , Animales , Sueros Inmunes/inmunología , Anticuerpos Antibacterianos/inmunología , Flagelos/inmunología , Ratones , Infecciones por Pseudomonas/inmunología , Infecciones por Pseudomonas/microbiologíaRESUMEN
A US collection of invasive Escherichia coli serotype O1 bloodstream infection (BSI) isolates were assessed for genotypic and phenotypic diversity as the basis for designing a broadly protective O-antigen vaccine. Eighty percent of the BSI isolate serotype O1 strains were genotypically ST95 O1:K1:H7. The carbohydrate repeat unit structure of the O1a subtype was conserved in the three strains tested representing core genome multi-locus sequence types (MLST) sequence types ST95, ST38, and ST59. A long-chain O1a CRM197 lattice glycoconjugate antigen was generated using oxidized polysaccharide and reductive amination chemistry. Two ST95 strains were investigated for use in opsonophagocytic assays (OPA) with immune sera from vaccinated animals and in murine lethal challenge models. Both strains were susceptible to OPA killing with O1a glycoconjugate post-immune sera. One of these, a neonatal sepsis strain, was found to be highly lethal in the murine challenge model for which virulence was shown to be dependent on the presence of the K1 capsule. Mice immunized with the O1a glycoconjugate were protected from challenges with this strain or a second, genotypically related, and similarly virulent neonatal isolate. This long-chain O1a CRM197 lattice glycoconjugate shows promise as a component of a multi-valent vaccine to prevent invasive E. coli infections. IMPORTANCE: The Escherichia coli serotype O1 O-antigen serogroup is a common cause of invasive bloodstream infections (BSI) in populations at risk such as newborns and the elderly. Sequencing of US BSI isolates and structural analysis of O polysaccharide antigens purified from strains that are representative of genotypic sub-groups confirmed the relevance of the O1a subtype as a vaccine antigen. O polysaccharide was purified from a strain engineered to produce long-chain O1a O-antigen and was chemically conjugated to CRM197 carrier protein. The resulting glycoconjugate elicited functional antibodies and was protective in mice against lethal challenges with virulent K1-encapsulated O1a isolates.
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Infecciones por Escherichia coli , Escherichia coli , Glicoconjugados , Antígenos O , Animales , Antígenos O/inmunología , Antígenos O/genética , Ratones , Infecciones por Escherichia coli/prevención & control , Infecciones por Escherichia coli/microbiología , Infecciones por Escherichia coli/inmunología , Escherichia coli/genética , Escherichia coli/inmunología , Glicoconjugados/inmunología , Humanos , Serogrupo , Vacunas contra Escherichia coli/inmunología , Anticuerpos Antibacterianos/sangre , Anticuerpos Antibacterianos/inmunología , Femenino , Virulencia , Vacunas Conjugadas/inmunología , Tipificación de Secuencias Multilocus , Modelos Animales de Enfermedad , Bacteriemia/prevención & control , Bacteriemia/microbiología , Bacteriemia/inmunología , Proteínas BacterianasRESUMEN
Lyme disease (LD), caused by spirochete bacteria of the genus Borrelia burgdorferi sensu lato, remains the most common vector-borne disease in the northern hemisphere. Borrelia outer surface protein A (OspA) is an integral surface protein expressed during the tick cycle, and a validated vaccine target. There are at least 20 recognized Borrelia genospecies, that vary in OspA serotype. This study presents a new in silico sequence-based method for OspA typing using next-generation sequence data. Using a compiled database of over 400 Borrelia genomes encompassing the 4 most common disease-causing genospecies, we characterized OspA diversity in a manner that can accommodate existing and new OspA types and then defined boundaries for classification and assignment of OspA types based on the sequence similarity. To accommodate potential novel OspA types, we have developed a new nomenclature: OspA in silico type (IST). Beyond the ISTs that corresponded to existing OspA serotypes 1-8, we identified nine additional ISTs that cover new OspA variants in B. bavariensis (IST9-10), B. garinii (IST11-12), and other Borrelia genospecies (IST13-17). The IST typing scheme and associated OspA variants are available as part of the PubMLST Borrelia spp. database. Compared to traditional OspA serotyping methods, this new computational pipeline provides a more comprehensive and broadly applicable approach for characterization of OspA type and Borrelia genospecies to support vaccine development.
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Antígenos de Superficie , Proteínas de la Membrana Bacteriana Externa , Lipoproteínas , Enfermedad de Lyme , Proteínas de la Membrana Bacteriana Externa/genética , Enfermedad de Lyme/microbiología , Lipoproteínas/genética , Antígenos de Superficie/genética , Borrelia burgdorferi/genética , Borrelia burgdorferi/clasificación , Simulación por Computador , Humanos , Genoma Bacteriano , Grupo Borrelia Burgdorferi/genética , Grupo Borrelia Burgdorferi/clasificación , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Serogrupo , Filogenia , Vacunas BacterianasRESUMEN
Measurement of IgG antibodies against group B streptococcus (GBS) capsular polysaccharide (CPS) by use of a standardized and internationally accepted multiplex immunoassay is important for the evaluation of candidate maternal GBS vaccines in order to compare results across studies. A standardized assay is also required if serocorrelates of protection against invasive GBS disease are to be established in infant sera for the six predominant GBS serotypes since it would permit the comparison of results across the six serotypes. We undertook an interlaboratory study across five laboratories that used standardized assay reagents and protocols with a panel of 44 human sera to measure IgG antibodies against GBS CPS serotypes Ia, Ib, II, III, IV, and V. The within-laboratory intermediate precision, which included factors like the lot of coated beads, laboratory analyst, and day, was generally below 20% relative standard deviation (RSD) for all six serotypes, across all five laboratories. The cross-laboratory reproducibility was < 25% RSD for all six serotypes, which demonstrated the consistency of results across the different laboratories. Additionally, anti-CPS IgG concentrations for the 44-member human serum panel were established. The results of this study showed assay robustness and that the resultant anti-CPS IgG concentrations were reproducible across laboratories for the six GBS CPS serotypes when the standardized assay was used.
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Síndrome de Guillain-Barré , Inmunoglobulina G , Lactante , Humanos , Reproducibilidad de los Resultados , Inmunoensayo , Polisacáridos , Streptococcus agalactiaeRESUMEN
BACKGROUND: Group B streptococcus is a major cause of neonatal disease. Natural history studies have linked maternally transferred anti-group B streptococcus capsular polysaccharide antibodies with protection against infant group B streptococcus disease. Previous studies of capsular polysaccharide antibody concentration in European populations have used maternal (not infant) sera and a non-standardised assay. This study aimed to evaluate anti-capsular polysaccharide IgG concentrations associated with protection against invasive group B streptococcus disease in Finnish infants. METHODS: In this retrospective case-control study, we used cord sera from the Finnish DIPP study repository, which was obtained between Jan 1, 1995, and Dec 31, 2017. We included infants aged 6 months or younger with group B streptococcus infection (cases) and healthy infants (controls). We enrolled infants with invasive neonatal group B streptococcus (55 cases) and matched controls (229 controls) aged 6 months or younger after identification from Finnish health registers. We measured anti-capsular polysaccharide IgG (serotypes Ia-V) concentration using a standardised immunoassay and we estimated its relationship to disease risk using a Bayesian model. We used the derived risk-concentration curve to predict potential efficacy of six-valent group B streptococcus capsular polysaccharide vaccine (GBS6) based on previously reported immunogenicity data. FINDINGS: Most (32 [58%] of 55 cases) group B streptococcus cases were due to serotype III and anti-serotype III streptococcus capsular IgG concentrations were higher in serotype III-matched controls than in cases (p<0·001). 0·120-0·266 µg/mL serotype III-specific IgG was estimated to confer 75-90% risk reduction against serotype III disease. A universal risk-concentration curve, aggregating results across all six serotypes, yielded similar results. Application of this curve to GBS6 immunogenicity data predicted maternal immunisation to be more than 80% efficacious for prevention of infant group B streptococcus disease. INTERPRETATION: Higher neonatal anti-capsular polysaccharide serum IgG concentration at birth correlated with reduced risk of infant group B streptococcus disease in Finland. Based on these results, a maternal group B streptococcus capsular conjugate vaccine currently in development is predicted to be efficacious. FUNDING: Pfizer.
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Anticuerpos Antibacterianos , Inmunoglobulina G , Infecciones Estreptocócicas , Streptococcus agalactiae , Humanos , Finlandia/epidemiología , Estudios Retrospectivos , Streptococcus agalactiae/inmunología , Infecciones Estreptocócicas/inmunología , Infecciones Estreptocócicas/prevención & control , Infecciones Estreptocócicas/sangre , Infecciones Estreptocócicas/epidemiología , Estudios de Casos y Controles , Inmunoglobulina G/sangre , Inmunoglobulina G/inmunología , Femenino , Recién Nacido , Anticuerpos Antibacterianos/sangre , Anticuerpos Antibacterianos/inmunología , Masculino , Lactante , Vacunas Estreptocócicas/inmunología , Vacunas Estreptocócicas/administración & dosificación , Cápsulas Bacterianas/inmunologíaRESUMEN
To address the problem of increased antimicrobial resistance, we developed a glycoconjugate vaccine comprised of O-polysaccharides (OPS) of the four most prevalent serotypes of Klebsiella pneumoniae (KP) linked to recombinant flagellin types A and B (rFlaA and rFlaB) of Pseudomonas aeruginosa (PA). Flagellin is the major subunit of the flagellar filament. Flagella A and B, essential virulence factors for PA, are glycosylated with different glycans. We previously reported that while both rFlaA and rFlaB were highly immunogenic, only the rFlaB antisera reduced PA motility and protected mice from lethal PA infection in a mouse model of thermal injury. Since recombinant flagellin is not glycosylated, we examined the possibility that the glycan on native FlaA (nFlaA) might be critical to functional immune responses. We compared the ability of nFlaA to that of native, deglycosylated FlaA (dnFlaA) to induce functionally active antisera. O glycan was removed from nFlaA with trifluoromethanesulfonic acid. Despite the similar high-titered anti-FlaA antibody levels elicited by nFlaA, rFlaA, and dnFlaA, only the nFlaA antisera inhibited PA motility and protected mice following lethal intraperitoneal bacterial challenge. Both the protective efficacy and carrier protein function of nFlaA were retained when conjugated to KP O1 OPS. We conclude that unlike the case with FlaB O glycan, the FlaA glycan is an important epitope for the induction of functionally active anti-FlaA antibodies.
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Flagelina , Pseudomonas aeruginosa , Ratones , Animales , Flagelina/metabolismo , Anticuerpos , Klebsiella pneumoniae , Polisacáridos , Flagelos/metabolismo , Sueros InmunesRESUMEN
Introduction: Access to care is a major public health concern particularly in medically underserved areas (MUAs) (Zones d'Interventions Prioritaires). Teleconsultations were legalized in France in 2010, however, have been reimbursed by the national health insurance since 2018. Large-scale studies assessing the impact of teleconsultations on access to care are limited. The objective of this study was to evaluate the impact of teleconsultations in MUAs at a national scale. Methods: An observational, multicenter cross-sectional study was conducted in seven teleconsultation centers. Teleconsultations were included if they were with patients living in France and received ambulatory care at primary ambulatory care settings by registered medical doctors between August 1 and November 30, 2021. Each center provided a randomized sample of 3,000 case data per month, yielding a total of 84,000 patients. Teleconsultation incidence was measured in MUAs and non-MUAs as the primary outcome. Results: In total, 25.1% of French patients lived in MUAs, with a mean age of 30.1 ± 0.08 years. Incidence of teleconsultations was 1,964 per 100,000 compared with 787 per 100,000 in non-MUAs (p < 0.0001). Teleconsultations were mostly performed during the day (88.6%), on weekdays (90.6%), were booked (88.3%), involved a general practitioner (GP) (89.0%), and were carried out as a video consultation (96.5%). The median delay to access was 60 min for GPs. Discussion: This was the largest study of teleconsultations in France and the first in the world to pool data from competing telemedicine companies. The incidence of teleconsultations was higher in MUAs, which may show that teleconsultations improve access to care. Clinical Trial Registration number: NCT05311241.
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Médicos Generales , Consulta Remota , Humanos , Adulto , Estudios Transversales , Área sin Atención Médica , Atención Ambulatoria , Atención Primaria de SaludRESUMEN
BACKGROUND: Pulmonary endarterectomy (PEA) is the treatment of choice for patients with chronic thromboembolic pulmonary hypertension (CTEPH) with accessible lesions. Breathing pure oxygen (hyperoxia) during right heart catheterization (RHC) allows for the calculation of the right-to-left shunt fraction (Qs/Qt). In the absence of intracardiac shunt, Qs/Qt can be used as a marker of ventilation-perfusion mismatch in patients with CTEPH. This study involved investigating Qs/Qt after PEA and its relation to other disease-specific outcomes. STUDY DESIGN AND METHODS: This study is a retrospective study that focuses on patients with operable CTEPH who had Qs/Qt assessment during RHC before and 1 year after PEA. Additionally, 6 min walking distance (6MWD), WHO functional class (WHO-FC), and NT-proBNP were assessed to calculate a four-strata risk score. RESULTS: Overall, 16 patients (6 females) with a median age of 66 years (quartiles 55; 74) were included. After PEA, an improvement in mean pulmonary artery pressure (38 [32; 41] to 24 [18; 28] mmHg), pulmonary vascular resistance (5.7 [4.0; 6.8] to 2.5 [1.4; 3.8] WU), oxygen saturation (92 [88; 93]% to 94 [93; 95]%), WHO-FC, and risk score was observed (all p < 0.05). No improvement in median Qs/Qt could be detected (13.7 [10.0; 17.5]% to 13.0 [11.2; 15.6]%, p = 0.679). A total of 7 patients with improved Qs/Qt had a significant reduction in risk score compared to those without improved Qs/Qt. CONCLUSION: PEA did not alter Qs/Qt assessed after 1 year in operable CTEPH despite an improvement in hemodynamics and risk score, potentially indicating a persistent microvasculopathy. In patients whose shunt fraction improved with PEA, the reduced shunt was associated with an improvement in risk score.
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BACKGROUND: Natural history studies have correlated serotype-specific anti-capsular polysaccharide (CPS) IgG in newborns with a reduced risk of group B streptococcal disease. A hexavalent CPS-cross-reactive material 197 glycoconjugate vaccine (GBS6) is being developed as a maternal vaccine to prevent invasive group B streptococcus in young infants. METHODS: In an ongoing phase 2, placebo-controlled trial involving pregnant women, we assessed the safety and immunogenicity of a single dose of various GBS6 formulations and analyzed maternally transferred anti-CPS antibodies. In a parallel seroepidemiologic study that was conducted in the same population, we assessed serotype-specific anti-CPS IgG concentrations that were associated with a reduced risk of invasive disease among newborns through 89 days of age to define putative protective thresholds. RESULTS: Naturally acquired anti-CPS IgG concentrations were associated with a reduced risk of disease among infants in the seroepidemiologic study. IgG thresholds that were determined to be associated with 75 to 95% reductions in the risk of disease were 0.184 to 0.827 µg per milliliter. No GBS6-associated safety signals were observed among the mothers or infants. The incidence of adverse events and of serious adverse events were similar across the trial groups for both mothers and infants; more local reactions were observed in the groups that received GBS6 containing aluminum phosphate. Among the infants, the most common serious adverse events were minor congenital anomalies (umbilical hernia and congenital dermal melanocytosis). GBS6 induced maternal antibody responses to all serotypes, with maternal-to-infant antibody ratios of approximately 0.4 to 1.3, depending on the dose. The percentage of infants with anti-CPS IgG concentrations above 0.184 µg per milliliter varied according to serotype and formulation, with 57 to 97% of the infants having a seroresponse to the most immunogenic formulation. CONCLUSIONS: GBS6 elicited anti-CPS antibodies against group B streptococcus in pregnant women that were transferred to infants at levels associated with a reduced risk of invasive group B streptococcal disease. (Funded by Pfizer and the Bill and Melinda Gates Foundation; C1091002 ClinicalTrials.gov number, NCT03765073.).
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Infecciones Estreptocócicas , Vacunas Estreptocócicas , Streptococcus agalactiae , Femenino , Humanos , Lactante , Recién Nacido , Embarazo , Anticuerpos Antibacterianos , Inmunoglobulina G , Estudios Seroepidemiológicos , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/inmunología , Infecciones Estreptocócicas/prevención & control , Vacunas Combinadas/administración & dosificación , Vacunas Combinadas/efectos adversos , Vacunas Combinadas/inmunología , Vacunas Combinadas/uso terapéutico , Vacunas Conjugadas/administración & dosificación , Vacunas Conjugadas/efectos adversos , Vacunas Conjugadas/inmunología , Vacunas Conjugadas/uso terapéutico , Vacunas Estreptocócicas/administración & dosificación , Vacunas Estreptocócicas/efectos adversos , Vacunas Estreptocócicas/inmunología , Vacunas Estreptocócicas/uso terapéutico , Inmunidad Materno-Adquirida/inmunologíaRESUMEN
Group B streptococcus (GBS) is a leading cause of neonatal morbidity and mortality worldwide. Development of a maternal vaccine to protect newborns through placentally transferred antibody is considered feasible based on the well-established relationship between anti-GBS capsular polysaccharide (CPS) IgG levels at birth and reduced risk of neonatal invasive GBS. An accurately calibrated serum reference standard that can be used to measure anti-CPS concentrations is critical for estimation of protective antibody levels across serotypes and potential vaccine performance. For this, precise weight-based measurement of anti-CPS IgG in sera is required. Here, we report an improved approach for determining serum anti-CPS IgG levels using surface plasmon resonance with monoclonal antibody standards, coupled with a direct Luminex-based immunoassay. This technique was used to quantify serotype-specific anti-CPS IgG levels in a human serum reference pool derived from subjects immunized with an investigational six-valent GBS glycoconjugate vaccine.
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Maturation of antibody responses entails somatic hypermutation (SHM), class-switch DNA recombination (CSR), plasma cell differentiation, and generation of memory B cells, and it is thought to require T cell help. We showed that B cell Toll-like receptor 4 (TLR4)-B cell receptor (BCR) (receptor for antigen) coengagement by 4-hydroxy-3-nitrophenyl acetyl (NP)-lipopolysaccharide (LPS) (Escherichia coli lipid A polysaccharide O-antigen) or TLR5-BCR coengagement by Salmonella flagellin induces mature antibody responses to NP and flagellin in Tcrß-/-Tcrδ-/- and NSG/B mice. TLR-BCR coengagement required linkage of TLR and BCR ligands, "linked coengagement." This induced B cell CSR/SHM, germinal center-like differentiation, clonal expansion, intraconal diversification, plasma cell differentiation, and an anamnestic antibody response. In Tcrß-/-Tcrδ-/- mice, linked coengagement of TLR4-BCR by LPS or TLR5-BCR by flagellin induced protective antibodies against E. coli or Salmonella Typhimurium. Our findings unveiled a critical role of B cell TLRs in inducing neutralizing antibody responses, including those to microbial pathogens, without T cell help.
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Formación de Anticuerpos , Receptor Toll-Like 4 , Ratones , Animales , Receptor Toll-Like 4/genética , Anticuerpos Neutralizantes , Lipopolisacáridos , Escherichia coli , Flagelina , Receptor Toll-Like 5/genética , Linfocitos T , Receptores de Antígenos de Linfocitos BRESUMEN
OBJECTIVES: Thyroid cancer incidence in France has increased rapidly in recent decades. Most of this increase has been attributed to overdiagnosis, the major consequence of which is overtreatment. We aimed to estimate the cost of thyroid cancer management in France and the corresponding cost proportion attributable to the treatment of overdiagnosed cases. METHODS: Multiple data sources were integrated: the mean cost per patient with thyroid cancer was estimated by using the Echantillon Généraliste des Bénéficiaires data set; thyroid cancer cases attributable to overdiagnosis were estimated for 21 departments using data from the French network of cancer registries and extrapolated to the whole country; medical records from 6 departments were used to refine the diagnosis and care pathway. RESULTS: Between 2011 and 2015, 33 911 women and 10 846 men in France were estimated to be diagnosed of thyroid cancer, with mean cost per capita of 6248. Among those treated, 8114 to 14 925 women and 1465 to 3626 men were due to overdiagnosis. The total cost of thyroid cancer patient management was 203.5 million (154.3 million for women and 49.3 million for men), of which between 59.9 million (or 29.4% of the total cost, lower bound) and 115.9 million (or 56.9% of the total cost, upper bound) attributable to treatment of overdiagnosed cases. CONCLUSIONS: The management of thyroid cancer represents not only a relevant clinical and public health problem in France but also a potentially important economic burden. Overdiagnosis and corresponding associated treatments play an important role on the total costs of thyroid cancer management.
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Neoplasias de la Tiroides , Masculino , Humanos , Femenino , Neoplasias de la Tiroides/diagnóstico , Neoplasias de la Tiroides/epidemiología , Neoplasias de la Tiroides/terapia , Incidencia , Francia/epidemiologíaRESUMEN
Objectives: Immuno-epidemiological studies of orally acquired, enteric pathogens such as nontyphoidal Salmonella (NTS) often focus on serological measures of immunity, ignoring potentially relevant oral mucosal responses. In this study we sought to assess the levels and detectability of both oral fluid and serum IgG and IgA to NTS antigens, in endemic and non-endemic populations. Methods: IgG and IgA antibodies specific for Salmonella Typhimurium and Salmonella Enteritidis O antigen and phase 1 flagellin were assessed using Enzyme Linked Immunosorbent Assay (ELISA). Paired oral fluid and serum samples were collected from groups of 50 UK adults, Kenyan adults and Kenyan infants. Additionally, oral fluid alone was collected from 304 Kenyan individuals across a range of ages. Results: Antigen-specific IgG and IgA was detectable in the oral fluid of both adults and infants. Oral fluid antibody increased with age, peaking in adulthood for both IgG and IgA but a separate peak was also observed for IgA in infants. Oral fluid and serum responses correlated for IgG but not IgA. Despite standardised collection the relationship between oral fluid volume and antibody levels varied with age and country of origin. Conclusions: Measurement of NTS-specific oral fluid antibody can be used to complement measurement of serum antibody. For IgA in particular, oral fluid may offer insights into how protective immunity to NTS changes as individuals transition with age, from maternal to acquired systemic and mucosal immunity. This may prove useful in helping to guide future vaccine design.
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Since its initial identification in 1986, Lyme disease has been clinically diagnosed in 29 provinces in China; however, national incidence data are lacking. To summarize Lyme disease seropositivity data among persons across China, we conducted a systematic literature review of Chinese- and English-language journal articles published during 2005â2020. According to 72 estimates that measured IgG by using a diagnostic enzyme-linked assay (EIA) alone, the seropositivity point prevalence with a fixed-effects model was 9.1%. A more conservative 2-tier testing approach of EIA plus a confirmatory Western immunoblot (16 estimates) yielded seropositivity 1.8%. Seropositivity by EIA for high-risk exposure populations was 10.0% and for low-risk exposure populations was 4.5%; seropositivity was highest in the northeastern and western provinces. Our analysis confirms Lyme disease prevalence, measured by seropositivity, in many Chinese provinces and populations at risk. This information can be used to focus prevention measures in provinces where seropositivity is high.
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Borrelia burgdorferi , Enfermedad de Lyme , Humanos , Enfermedad de Lyme/diagnóstico , Enfermedad de Lyme/epidemiología , Western Blotting , Prevalencia , China/epidemiologíaRESUMEN
Group B streptococcus (Streptococcus agalactiae, GBS) is an important cause of life-threatening disease in newborns. Pregnant women colonized with GBS can transmit the bacteria to the developing fetus, as well as to their neonates during or after delivery where infection can lead to sepsis, meningitis, pneumonia, or/and death. While intrapartum antibiotic prophylaxis (IAP) is the standard of care for prevention of invasive GBS disease in some countries, even in such settings a substantial residual burden of disease remains. A GBS vaccine administered during pregnancy could potentially address this important unmet medical need and provide an adjunct or alternative to IAP for the prevention of invasive GBS disease in neonates. A hurdle for vaccine development has been relatively low disease rates making efficacy studies difficult. Given the well-accepted inverse relationship between anti-GBS capsular polysaccharide antibody titers at birth and risk of disease, licensure using serological criteria as a surrogate biomarker represents a promising approach to accelerate the availability of a GBS vaccine.
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Complicaciones Infecciosas del Embarazo , Infecciones Estreptocócicas , Vacunas Estreptocócicas , Femenino , Humanos , Lactante , Recién Nacido , Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Embarazo , Complicaciones Infecciosas del Embarazo/microbiología , Complicaciones Infecciosas del Embarazo/prevención & control , Infecciones Estreptocócicas/prevención & control , Streptococcus agalactiaeRESUMEN
BACKGROUND: Pseudomonas aeruginosa is an opportunistic pathogen that causes a wide range of acute and chronic infections and is frequently associated with healthcare-associated infections. Because of its ability to rapidly acquire resistance to antibiotics, P. aeruginosa infections are difficult to treat. Alternative strategies, such as a vaccine, are needed to prevent infections. We collected a total of 413 P. aeruginosa isolates from the blood and cerebrospinal fluid of patients from 10 countries located on 4 continents during 2005-2017 and characterized these isolates to inform vaccine development efforts. We determined the diversity and distribution of O antigen and flagellin types and antibiotic susceptibility of the invasive P. aeruginosa. We used an antibody-based agglutination assay and PCR for O antigen typing and PCR for flagellin typing. We determined antibiotic susceptibility using the Kirby-Bauer disk diffusion method. RESULTS: Of the 413 isolates, 314 (95%) were typed by an antibody-based agglutination assay or PCR (n = 99). Among the 20 serotypes of P. aeruginosa, the most common serotypes were O1, O2, O3, O4, O5, O6, O8, O9, O10 and O11; a vaccine that targets these 10 serotypes would confer protection against more than 80% of invasive P. aeruginosa infections. The most common flagellin type among 386 isolates was FlaB (41%). Resistance to aztreonam (56%) was most common, followed by levofloxacin (42%). We also found that 22% of strains were non-susceptible to meropenem and piperacillin-tazobactam. Ninety-nine (27%) of our collected isolates were resistant to multiple antibiotics. Isolates with FlaA2 flagellin were more commonly multidrug resistant (p = 0.04). CONCLUSIONS: Vaccines targeting common O antigens and two flagellin antigens, FlaB and FlaA2, would offer an excellent strategy to prevent P. aeruginosa invasive infections.
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Farmacorresistencia Bacteriana , Pseudomonas aeruginosa/clasificación , Pseudomonas aeruginosa/efectos de los fármacos , Antibacterianos/farmacología , Farmacorresistencia Bacteriana/efectos de los fármacos , Farmacorresistencia Bacteriana/genética , Flagelina/clasificación , Flagelina/genética , Humanos , Pruebas de Sensibilidad Microbiana , Antígenos O/clasificación , Antígenos O/inmunología , Infecciones por Pseudomonas/microbiología , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/aislamiento & purificación , Serogrupo , SerotipificaciónRESUMEN
The World Health Organization estimates ~180,000 deaths occur annually from burn-related injuries. Many victims who survive the initial burn trauma succumb to bacterial infections that lead to sepsis during treatment. Although advancements in burn care continue to improve in high-income countries due to their burn centers and advanced research, low and middle-income countries continue to see high frequencies of burn injuries and burn-related deaths due to secondary infections. Bacterial-derived sepsis is the most life-threatening danger for people that survive burn injuries. Here we provide evidence for the first time that a subeschar seroma forms postburn even in the absence of infection in mice. The seroma fills with a volume estimated at 500 µL of fluid, 25% of the blood supply, free of red blood cells. The seroma fluid supports robust Pseudomonas aeruginosa (PA) growth and contains inflammatory cytokines and chemokines, which recruit immature neutrophils and monocytes to the seroma in the absence of endothelial breakdown. These immune cells fail to contain PA expansion and dissemination. This recruitment of monocytes and immature neutrophils may result in sequestering these critical immune cells away from other tissues during a pivotal time during bacterial dissemination, promoting PA-mediated sepsis.
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Quemaduras , Infecciones por Pseudomonas , Sepsis , Traumatismos de los Tejidos Blandos , Animales , Modelos Animales de Enfermedad , Humanos , Ratones , Pseudomonas aeruginosa , Sepsis/microbiología , SeromaRESUMEN
BACKGROUND: France is among the countries showing fastest growth of thyroid cancer (TC) incidence and highest incidence rates in Europe. This study aimed to clarify the temporal and geographical variations of TC in France and to quantify the impact of overdiagnosis. METHODS: We obtained TC incidence data in 1986-2015, and mortality data in 1976-2015, for eight French departments covering 8% of the national population, and calculated the age-standardised rates (ASR). We estimated the average annual percent changes (AAPC) of TC incidence, overall and by department and histological subtype. Numbers and proportions of TC cases attributable to overdiagnosis were estimated by department and period, based on the comparison between the shape of the age-specific curves with that observed prior to changes in diagnostic practice. RESULTS: During 1986-2015, there were 13,557 TC cases aged 15-84 years. Large variations of TC incidence were observed across departments, with the highest ASR and the fastest increase in Isère. Papillary subtype accounted for 82.8% of the cases, and presented an AAPC of 7.0% and 7.6% in women and men, respectively. Anaplastic TC incidence decreased annually 3.0% in women and 0.8% in men. Mortality rates declined consistently for all departments. The absolute number (and proportion) of TC cases attributable to overdiagnosis grew from 1074 (66%) in 1986-1995 to 3830 (72%) in 2006-2015 in women, and varied substantially across departments. CONCLUSIONS: Overdiagnosis plays an important role in the temporal and regional variations of TC incidence in France. Monitoring the time trends and regulating the regional healthcare practice are needed to reduce its impact.
Asunto(s)
Sobrediagnóstico , Neoplasias de la Tiroides , Femenino , Francia/epidemiología , Humanos , Incidencia , Masculino , Uso Excesivo de los Servicios de Salud , Sistema de Registros , Neoplasias de la Tiroides/diagnóstico , Neoplasias de la Tiroides/epidemiologíaRESUMEN
At present, the dramatic rise in antimicrobial resistance (AMR) among important human bacterial pathogens is reaching a state of global crisis threatening a return to the pre-antibiotic era. AMR, already a significant burden on public health and economies, is anticipated to grow even more severe in the coming decades. Several licensed vaccines, targeting both bacterial (Haemophilus influenzae type b, Streptococcus pneumoniae, Salmonella enterica serovar Typhi) and viral (influenza virus, rotavirus) human pathogens, have already proven their anti-AMR benefits by reducing unwarranted antibiotic consumption and antibiotic-resistant bacterial strains and by promoting herd immunity. A number of new investigational vaccines, with a potential to reduce the spread of multidrug-resistant bacterial pathogens, are also in various stages of clinical development. Nevertheless, vaccines as a tool to combat AMR remain underappreciated and unfortunately underutilized. Global mobilization of public health and industry resources is key to maximizing the use of licensed vaccines, and the development of new prophylactic vaccines could have a profound impact on reducing AMR.
RESUMEN
Of the 486,000 burn injuries that required medical treatment in the United States in 2016, 40,000 people were hospitalized, with >3,000 fatalities. After burn injury, humans are at increased risk of sepsis and mortality from infections caused by Pseudomonas aeruginosa, an opportunistic pathogen. We hypothesize that systemic events were initiated from the burn that increased the host's susceptibility to P. aeruginosa. A nonlethal 10% total body surface area (TBSA), full-thickness flame burn was performed in CD-1 mice without and with subsequent P. aeruginosa (strain M2) infection. The 50% lethal dose for subcutaneous infection with P. aeruginosa M2 at the burn site immediately after the burn decreased by 6 log, with mortality occurring between 18 and 26 h, compared with P. aeruginosa-infected mice without burn injury. Bacteria in distal organs were detected by 18 h, concurrent with the onset of clinical symptoms. Serum proinflammatory cytokines (interleukin-6 [IL-6], IL-1ß, gamma interferon, and tumor necrosis factor alpha) and the anti-inflammatory cytokine IL-10 were first detected at 12 h postburn with infection and continued to increase until death. Directly after burn alone, serum levels of HMGB1, a danger-associated molecular pattern and TLR4 agonist, transiently increased to 50 ng/ml before returning to 20 ng/ml. Burn with P. aeruginosa infection increased serum HMGB1 concentrations >10-fold (250 ng/ml) at the time of death. This HMGB1-rich serum stimulated TLR4-mediated NF-κB activation in a TLR4 reporter cell line. Treatment of infected burned mice with P5779, a peptide inhibitor of HMGB1, increased the mean survival from 23 to 42 h (P < 0.0001). We conclude that the high level of serum HMGB1, which preceded the increase in proinflammatory cytokines, is associated with postburn mortality.