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1.
Am J Perinatol ; 41(S 01): e1451-e1458, 2024 05.
Artículo en Inglés | MEDLINE | ID: mdl-38134940

RESUMEN

OBJECTIVE: This study aimed to examine fetal and neonatal inflammatory and neurologic complications associated with maternal coronavirus disease 2019 (COVID-19) infection. STUDY DESIGN: Case-series using a convenience sample of neonates cared for in a large referral-based children's hospital neonatal intensive care unit between September 2021 and May 2022. RESULTS: We identified seven neonates with exposure to maternal severe acute respiratory syndrome related coronavirus 2 (SARS-CoV-2) and a presentation consistent with inflammatory complications. All had some degree of neurologic injury with neuroimaging findings including restricted diffusion indicating injury in the white matter, cortex, deep gray structures, and splenium of the corpus callosum as well as intracranial hemorrhage. In addition, many infants had cytopenia and abnormal coagulation studies. Placental pathology, when available, revealed inflammation, clot with calcifications, and hematomas with associated infarcts. CONCLUSION: Neonates born to mothers with SARS-CoV-2, even when negative for the virus themselves, may have complications consistent with a systemic inflammatory syndrome. Placental pathology as well as neurologic imaging in infants with neurologic findings may help to support this diagnosis. KEY POINTS: · A systemic inflammatory response may cause illness in babies born to mothers with a history of COVID-19.. · Inflammatory markers and placental pathology are helpful in supporting this diagnosis.. · Consider neuroimaging in infants of mothers with a history of COVID-19 with neurologic findings..


Asunto(s)
COVID-19 , Complicaciones Infecciosas del Embarazo , SARS-CoV-2 , Síndrome de Respuesta Inflamatoria Sistémica , Humanos , COVID-19/complicaciones , Femenino , Embarazo , Recién Nacido , Complicaciones Infecciosas del Embarazo/virología , Masculino , Placenta/patología , Placenta/virología , Adulto , Transmisión Vertical de Enfermedad Infecciosa , Neuroimagen
2.
J Nutr ; 152(12): 2744-2753, 2023 01 14.
Artículo en Inglés | MEDLINE | ID: mdl-36055798

RESUMEN

BACKGROUND: Previously, a novel oat ready-to-use therapeutic food (o-RUTF) resulted in improved recovery from severe acute malnutrition (SAM) when compared to a standard RUTF (s-RUTF). The o-RUTF contained 18% oat, while the s-RUTF has no cereal ingredients. OBJECTIVES: We determined the effects of o-RUTF on intestinal permeability, as measured by lactulose permeability, and the 16S ribosomal RNA (rRNA) fecal microbiome configuration of children with SAM. METHODS: This was a prospective, randomized, double-blinded, controlled clinical trial. Sierra Leonean children aged 6-59 mo with SAM, defined by a midupper arm circumference < 11.5 cm, were randomized to receive o-RUTF or s-RUTF. All children received 7 d of amoxicillin per guidelines. Lactulose permeability testing and fecal 16S rRNA sequencing were performed at baseline and after 4 wk of therapy. The change in lactulose permeability was the primary outcome, while the fecal 16S rRNA configuration at 4 wk was a secondary outcome. RESULTS: Of the 129 children enrolled, lactulose permeability testing was completed by 100 at baseline and 82 at week 4. After 4 wk of therapeutic feeding, there were no differences in lactulose permeability between the o-RUTF and s-RUTF groups (P = 0.84), and over half of children had increased lactulose permeability (50% s-RUTF compared with 58% o-RUTF, mean difference = -7.5%; 95% CI: -29.2, 15.2; P = 0.50). After 4 wk of feeding, there were no differences in the 16S rRNA configurations between the o-RUTF and s-RUTF groups (Permanova, 999 permutations; P = 0.648; pseudo-F = 0.581), nor were there differences in α or ß diversity. CONCLUSIONS: Despite remarkably different compositions of o-RUTF and s-RUTF, no differences were identified in lactulose permeability or the fecal 16S rRNA configuration among children with SAM receiving these foods. These results suggest that the o-RUTF exerts its beneficial effects through mechanisms other than reducing intestinal permeability or altering the fecal 16S configuration. This trial was registered at clinicaltrials.gov as NCT04334538.


Asunto(s)
Desnutrición , Desnutrición Aguda Severa , Humanos , Niño , Lactante , ARN Ribosómico 16S , Avena , Sierra Leona , Lactulosa , Estudios Prospectivos , Resultado del Tratamiento , Desnutrición Aguda Severa/terapia , Grano Comestible , Comida Rápida
3.
J Trop Pediatr ; 67(3)2021 07 02.
Artículo en Inglés | MEDLINE | ID: mdl-32853356

RESUMEN

OBJECTIVE: The aim of this study is to determine the association of intrapartum risk factors and infant clinical indicators using the National Institute for Health and Care Excellence (NICE) criteria with culture-positive early-onset neonatal sepsis (EONS) from a rural secondary healthcare facility where intrapartum prophylactic antibiotics are routinely administered to high-risk mothers. METHODS: A single-center prospective observational study was conducted between July 2017 and September 2018. All intramural neonates with at least one NICE criteria at less than 72 h of life, were included. Univariate logistic regression and multivariable logistic backward elimination analyses were conducted to investigate individual risk factors and predictive models for culture proven EONS. RESULTS: Of 236 newborns who were at risk for EONS by NICE criteria, 32 (13.8%) had positive blood cultures. Klebsiella species (n = 13, 39.4%) and Acinetobacter species (n = 11, 33.3%) were the most common isolated bacteria. In univariate analysis, the number of infant clinical indicators were associated with culture positive EONS (OR 1.36; 95% CI 1.01-1.81), but not the number of intrapartum risk factors (OR 0.76; 95% CI 0.4-1.29). The multivariate logistic regression with backward elimination procedure suggested that a model including absolute neutrophil count [adjusted OR (aOR) 0.81; 95% CI 0.72-0.92], C-reactive protein (aOR 1.24; 95% CI 1.08-1.43) and the number of clinical indicators (aOR 1.29; 95% CI 0.93-1.80) could be useful to predict culture positive EONS in our setting. CONCLUSION: In this maternal and neonatal cohort, infant clinical indicators rather than intrapartum risk factors were associated with culture confirmed EONS.


Asunto(s)
Sepsis Neonatal , Sepsis , Femenino , Hospitales Rurales , Humanos , Lactante , Recién Nacido , Sepsis Neonatal/diagnóstico , Sepsis Neonatal/epidemiología , Parto , Embarazo , Factores de Riesgo , Atención Secundaria de Salud
4.
J Pediatr Gastroenterol Nutr ; 68(5): 734-737, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-31022095

RESUMEN

Malnutrition in children is most often attributed to inadequate nutrient intake. Utilizing data from 2 prospective, randomized controlled trials of complimentary feeding with supplemental legumes (n = 693, ages 6-24 months) in 2 Malawian villages, Masenjere, and Limera, we document a high rate 70/693 (10.1%) of acute malnutrition (AM). Risks for AM in this setting, as determined by Cox regression analysis, include study village (hazard ratio [HR] 3.0), prior malnutrition (HR 4.12), stunting (HR 2.87), and a marker of food insecurity (HR 1.89). Comparison of Masenjere to Limera demonstrate adequate and similar nutritional intake yet an increased rate of AM in Masenjere, 56 of 400 (14.0%) versus 14 of 293 (4.8%), and stunting, 140 of 400 (35%) versus 80 of 293 (27%), environmental enteric dysfunction 246 of 400 (71%) versus 181/293 (67%), and infectious symptoms (cough and diarrhea). Masenjere did have cleaner water and less food insecurity 200 of 399 (50.5%) versus 204 of 293 (69.6%). These findings suggest adequate complementary nutrient intake does not protect young children against AM.


Asunto(s)
Trastornos del Crecimiento/epidemiología , Desnutrición/epidemiología , Enfermedad Aguda , Preescolar , Suplementos Dietéticos , Femenino , Trastornos del Crecimiento/prevención & control , Humanos , Lactante , Fenómenos Fisiológicos Nutricionales del Lactante , Malaui/epidemiología , Masculino , Desnutrición/prevención & control , Estado Nutricional , Estudios Prospectivos , Ensayos Clínicos Controlados Aleatorios como Asunto , Factores de Riesgo
5.
Early Hum Dev ; 198: 106126, 2024 Sep 27.
Artículo en Inglés | MEDLINE | ID: mdl-39348773

RESUMEN

Human milk (HM) exposure improves short- and long-term outcomes for infants due to a complex milieu of bioactive, stem cell, anti-inflammatory, anti-microbial, and nutritive components. Given this remarkable biologic fluid, non-nutritional utilization of HM as a targeted therapeutic is being explored in pre-clinical and clinical studies. This article describes recent research pertinent to non-nutritional uses of HM for neurologic, gastrointestinal, and infectious pathologies in neonates, as well as future directions.

6.
J Perinatol ; 44(6): 811-818, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38195921

RESUMEN

BACKGROUND: Associations of 2-year neurodevelopmental and behavioral outcomes with growth trajectories of preterm infants are unknown. METHODS: This secondary analysis of a preterm cohort examined in-hospital and discharge to 2-year changes in anthropometric z-scores. Two-year follow-up included Bayley Scales of Infant Development (BSID-III) and Child Behavior Checklist. RESULTS: Among 590 infants, adjusted in-hospital growth was not associated with any BSID-III subscale. Occipitofrontal circumference (OFC) growth failure (GF) in-hospital was associated with increased adjusted odds of attention problems (aOR 1.65 [1.03, 2.65]), aggressive behavior (aOR 2.34 [1.12, 4.89]), and attention-deficit-hyperactivity symptoms (aOR 1.86 [1.05, 3.30]). Infants with OFC GF at 2 years had lower adjusted BSID-III language scores (-4.0 [-8.0, -0.1]), increased odds of attention problems (aOR 2.29 [1.11, 4.74]), aggressive behavior (aOR 3.09 [1.00, 9.56]), and externalizing problems (aOR 3.01 [1.07, 8.45]) compared to normal OFC growth cohort. CONCLUSION: Infants with OFC GF are at risk for neurodevelopmental and behavioral impairment. CLINICAL TRIAL REGISTRATION: This study is a secondary analysis of pre-existing data from the PENUT Trial Registration: NCT01378273.


Asunto(s)
Desarrollo Infantil , Recien Nacido Extremadamente Prematuro , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Trastorno por Déficit de Atención con Hiperactividad , Estudios de Seguimiento , Recien Nacido Extremadamente Prematuro/crecimiento & desarrollo , Trastornos del Neurodesarrollo/epidemiología , Trastornos del Neurodesarrollo/etiología
7.
Am J Clin Nutr ; 2024 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-39307188

RESUMEN

BACKGROUND: Bovine milk is a beneficial ingredient in teh treatment of malnutrition. OBJECTIVES: Our objectives were to determine the effect of dietary milk protein and milk carbohydrate on the intestinal permeability, fecal 16S rRNA gene configuration, and fecal metabolomics of children with moderate malnutrition. METHODS: This was a randomized, double-blind, controlled trial among 413 children with wasting in rural Sierra Leone who received 1 of the following 4 supplementary foods, which differed in sources of protein and carbohydrate: milk protein and milk carbohydrate (MPMC), milk protein and vegetable carbohydrate (MPVC), vegetable protein and milk carbohydrate (VPMC), or a control group consuming entirely vegetable-based food (VPVC). After 4 wk, urine and stool were collected from participants enrolled with mid-upper arm circumference of <12.1 cm. Urine was analyzed for lactulose excretion (%L). Stool samples were subjected to both 16S rRNA gene analysis to assess ß-diversity and untargeted metabolomic abundance. RESULTS: Among the 386 children who completed permeability testing, the mean difference (95% CI) in %L excretion as compared with VPVC was 0.01 (-0.05, 0.07) for MPMC, 0.05 (-0.01, 0.11) for MPVC, and 0.01 (-0.05, 0.07) for VPMC. Of the 374 children who provided a stool sample that was analyzed, the ß-diversity among bacterial taxa was similar between dietary groups (P > 0.05 for all comparisons). No significant differences between dietary groups were seen among the 20 most abundant bacterial taxa. Among the 5769 unique metabolomic features identified, greater flavonoid levels in VPVC were seen. CONCLUSIONS: Abnormal intestinal permeability do not improve with 4 wk of supplementary feeding. Fecal rRNA do not differ with consumption of different diets. This trial was registered at clinicaltrials.gov as NCT04216043.

8.
Semin Perinatol ; 48(5): 151927, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38897828

RESUMEN

Early nutritional exposures, including during embryogenesis and the immediate postnatal period, affect offspring outcomes in both the short- and long-term. Alterations of these modifiable exposures shape the developing gut microbiome, intestinal development, and even neurodevelopmental outcomes. A gut-brain axis exists, and it is intricately connected to early life feeding and nutritional exposures. Here, we seek to discuss the (1) origins of the gut-brain access and relationship with neurodevelopment, (2) components of human milk (HM) beyond nutrition and their role in the developing newborn, and (3) clinical application of nutritional practices, including fluid management and feeding on the development of the gut-brain axis, and long-term neurodevelopmental outcomes. We conclude with a discussion on future directions and unanswered questions that are critical to provide further understanding and insight into how clinicians and healthcare providers can optimize early nutritional practices to ensure children not only survive, but thrive, free of neurodevelopmental impairment.


Asunto(s)
Eje Cerebro-Intestino , Microbioma Gastrointestinal , Fenómenos Fisiológicos Nutricionales del Lactante , Leche Humana , Humanos , Recién Nacido , Microbioma Gastrointestinal/fisiología , Fenómenos Fisiológicos Nutricionales del Lactante/fisiología , Eje Cerebro-Intestino/fisiología , Lesiones Encefálicas/fisiopatología , Desarrollo Infantil/fisiología , Encéfalo/fisiopatología , Trastornos del Neurodesarrollo/etiología , Trastornos del Neurodesarrollo/fisiopatología , Femenino , Recien Nacido Prematuro
9.
Res Sq ; 2023 Aug 09.
Artículo en Inglés | MEDLINE | ID: mdl-37609333

RESUMEN

Introduction: The association of 2-year neurodevelopmental and behavioral outcomes with in-hospital or post-discharge growth failure (GF) using contemporary definitions for preterm infants is unknown. Methods: In a secondary analysis of a preterm cohort, changes in anthropometric z-scores were examined between birth and hospital discharge, and from discharge to 2 years. The 2-year evaluation included Bayley Scales of Infant Development (BSID-III) and Child Behavior Checklist (CBCL). Results: Among 629 infants, accelerated linear growth from birth to discharge was associated with higher BSID-III cognitive scores (+ 3.2 points [IQR 0.02, 6.4]) while in-hospital GF was not associated with any outcomes. Infants with weight GF after discharge had lower BSID-III motor scores (-3.1 points [-5.9, -0.2]). Infants with accelerated weight growth after discharge had increased odds of behavioral problems on the CBCL (aOR 1.9 [1.03, 3.5]). Discussion: In-hospital and post-hospitalization growth metrics are modestly associated with neurodevelopmental outcomes with length gains apparently most beneficial.

10.
Curr Dev Nutr ; 6(10): nzac138, 2022 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-36475019

RESUMEN

Background: Low birth weight (LBW) infants are at increased risk of morbidity and mortality. Identification of LBW may not occur in settings where access to reliable scales is limited. Mid-upper arm circumference (MUAC) may be an accessible, low-cost measure to identify LBW and vulnerable infants. Objectives: We explored the validity of newborn MUAC in identifying LBW and vulnerable newborns in rural Sierra Leone. Methods: This study was a secondary analysis of infant data from a randomized controlled clinical trial of supplementary food and anti-infective therapies compared with standard care for undernourished pregnant women. Data for singleton liveborn infants with birth measurement and 6-mo survival data were included in this analysis. The primary outcome was validity of MUAC in identifying low-birth weight (LBW) neonates. Secondary outcomes included validity of MUAC and head circumference (HC) in identifying weight-for-length z-score (WLZ) <-2, length-for-age z-score (LAZ) <-2, neonatal mortality, and mortality within the first 6 mo of life. Results: The study population included 1167 infants, 229 (19.6%) with LBW. Birth MUAC (r = 0.817) and HC (r = 0.752) were highly correlated with birth weight. MUAC (AUC: 0.905; 95% CI: 0.884, 0.925) performed superiorly to HC (AUC: 0.88; 95% CI: 0.856, 0.904) in identifying LBW. The MUAC for identifying LBW was 9.6 cm (sensitivity: 0.86; specificity: 0.78). Neither MUAC nor HC reliably identified newborns with WLZ <-2 or LAZ <-2. MUAC ≤9.0 cm was the ideal cutoff for neonatal mortality (sensitivity: 53.3%; specificity: 89.7%; HR: 9.57; 95% CI: 1.86, 49.30). Birth anthropometrics did not reliably identify infants at risk of death in the first 6 mo of life. Conclusions: MUAC was used successfully to identify LBW infants and infants at risk of neonatal mortality in Sierra Leone. Further evidence is needed to support increased use of newborn MUAC measurement to identify LBW infants and infants at risk of neonatal mortality in community settings where scales are not available. Primary trial was registered at clinicaltrials.gov as NCT03079388. Lay Summary: Mid-upper arm circumference (MUAC) can be used to identify infants with low birth weight and infants at risk for neonatal mortality, with an MUAC ≤9.0 cm indicating the highest risk.

11.
BMJ Open ; 12(2): e049783, 2022 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-35177442

RESUMEN

OBJECTIVES: To investigate the feasibility of eye-tracking-based testing of the speed of visual orienting in malnourished young children at rural clinics in Sierra Leone. DESIGN: Prospective dual cohort study nested in a cluster-randomised trial. SETTING: 8 sites participating in a cluster-randomised trial of supplementary feeding for moderate acute malnutrition (MAM). PARTICIPANTS: For the MAM cohort, all infants aged 7-11 months at the eight sites were enrolled, 138 altogether. For controls, a convenience sample of all non-malnourished infants aged 7-11 months at the same sites were eligible, 60 altogether. A sample of 30 adults at the sites also underwent eye-tracking tests as a further control. INTERVENTIONS: Infants with MAM were provided with supplementary feeding. OUTCOME MEASURES: The primary outcomes were feasibility and reliability of eye-tracking-based testing of saccadic reaction time (SRT). Feasibility was assessed by the percent of successful tests in the infants. Reliability was measured with intraclass correlation coefficients (ICCs). Secondary outcomes were mean SRT based on nutritional state as well as and changes in mean SRT after supplementary feeding of MAM children. RESULTS: Infants exhibited consistent orienting to targets on a computer screen (>95% of valid trials). Mean SRTs had moderate stability within visits (ICCs 0.60-0.69) and across the 4-week test-retest interval (0.53) in infants; the adult control group had greater SRT stability (within visit ICC=0.92). MAM infants had a trend toward higher adjusted SRT at baseline (difference=12.4 ms, 95% CI -2 to 26.9, p=0.09) and improvement in SRT 4 weeks thereafter (difference=-14 ms, 95% CI -26.2 to -1.7, p=0.025) compared with age-matched controls. CONCLUSIONS: The results demonstrate the feasibility of eye-tracking-based testing in a resource-poor field setting and suggest eye-tracking measures have utility in the detection of group level effects of supplementary feeding.


Asunto(s)
Cognición , Tecnología de Seguimiento Ocular , Adulto , Niño , Preescolar , Estudios de Cohortes , Humanos , Lactante , Estudios Prospectivos , Reproducibilidad de los Resultados , Sierra Leona
12.
Curr Dev Nutr ; 5(2): nzab007, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33659773

RESUMEN

BACKGROUND: Ready-to-use therapeutic food (RUTF) given at 175 kcal/kg per day throughout severe acute malnutrition (SAM) treatment is recommended. Some treatment programs have diverged from this paradigm in 2 ways: reducing the supplemental food dose to 75 kcal/kg per day when midupper arm circumference (MUAC) is >11.4 cm or simplifying to a fixed-dose regimen. OBJECTIVE: The objective was to determine if transitioning to an optimized, fixed-dose supplementary feeding regimen during SAM treatment when MUAC is >11.4 cm would result in noninferior gain in MUAC compared with standard treatment. METHODS: Using data from 2 clinical trials conducted in Sierra Leone, a retrospective dual-cohort study was performed. The 2 cohorts included children with SAM who had improved to meet criteria for moderate acute malnutrition (MAM). The standard dose cohort continued to receive weight-based RUTF at 175 kcal/kg per day, while the optimized dose cohort received fixed-dose, 500 kcal/d of supplementary feeding. The primary outcome was a noninferiority margin of 1 mm of MUAC after 4 wk of treatment, while secondary outcomes included rate of anthropometric changes as well as time-to-relapse to SAM or death. RESULTS: MUAC after 4 wk was noninferior (Δ: -0.1 mm; 95% CI: -0.05, 0.03; inferiority rejected P = 0.008). Rates of weight gain and MUAC gain were the same in the optimized-dose and standard-dose groups, whereas the rate of length gain was slower in the optimized-dose cohort. Time-to-relapse to SAM or death was not different (HR: 1.05; P = 0.71). CONCLUSIONS: This study supports the practice of treating children with SAM who have recovered to meet criteria for MAM with a reduced and fixed-dose regimen of RUTF. The results also raise the question of whether this strategy might adversely impact linear growth during SAM treatment.

14.
BMC Nutr ; 4: 15, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-32153879

RESUMEN

BACKGROUND: The negative synergy between poor nutritional status and infectious diseases is doubly detrimental in pregnancy. In Sierra Leone, maternal malnutrition is amongst the highest in the world, while maternal mortality is high at 1320/100,000 live births and stunting in under-five is 37.9%, ranked 110/132 worldwide. Maternal malnutrition has been associated with preterm birth, small-for-gestational age infants, and poor maternal outcomes. Infants born prematurely or small-for-gestational age experience higher mortality and are at risk for stunting and decreased cognitive performance. Nutritional interventions alone during pregnancy may not be as effective in the setting of increased inflammation from repeated infections. Interventions are needed to improve maternal outcomes and reduce stunting in this population. METHODS/DESIGN: This will be a prospective, randomized, controlled clinical effectiveness trial of an improved supplementary food plus anti-infective therapies compared to standard therapy in malnourished pregnant women. Pregnant women will be randomized to receive a low water activity, ready-to-use supplementary food plus five anti-infective interventions or the standard of care which is 3.5 kg corn/ soy blended flour with 350 mL vegetable oil every two weeks. The five anti-infective interventions are 1) insecticide-treated mosquito net at the time of enrollment into the study, 2) sulfadoxine-pyrimethamine given every 4 weeks, beginning at enrollment or at 13 weeks' gestation, whichever is later, 3)azithromycin at a dose of 1 g given once at enrollment (after first trimester)and again during 28-34 weeks of gestation, 4)single dose 400 mg albendazole given in second trimester, and 5) testing and treatment for bacterial vaginosis at enrollment and again at 28-34 weeks of gestation. Treatment will be provided for the duration of the pregnancy. The primary outcome measure will be birth length. Secondary outcomes in the mothers will include rates of maternal weight gain and increase in mid-upper arm circumference, and time to maternal anthropometric recovery. Secondary outcomes in the infants will include birth weight, birth head circumference, and linear and ponderal growth. DISCUSSION: Malnutrition remains a major problem in the developing world with lasting maternal and infant consequences. Maternal malnutrition has been associated with intrauterine growth retardation, low birth weight (LBW), pre-term delivery and poor cognitive development. Nutritional interventions alone have not been successful in reducing stunting. By bundling nutritional and anti-infective interventions, we aim to reduce intrauterine growth restriction and low birth weight in moderately malnourished pregnant women in Sierra Leone. If successful, this bundle can easily be implemented by governments or non-governmental organizations. TRIAL REGISTRATION: Clinicaltrials.gov NCT03079388; Date: March 5, 2017.

16.
FEMS Microbiol Rev ; 23(2): 99-129, 1999 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-10234841

RESUMEN

Non-typable Haemophilus influenzae is a common commensal organism in the human upper respiratory tract and an important cause of localized respiratory tract disease. The pathogenesis of disease begins with bacterial colonization of the nasopharynx, a process that involves establishment on the mucosal surface and evasion of local immune mechanisms. Under the proper circumstances, the organism spreads contiguously to the middle ear, the sinuses, or the lungs, and then stimulates a brisk inflammatory response, producing symptomatic infection. In this review, we summarize our present understanding of the molecular determinants of this sequence of events. Continued investigation of the molecular mechanism of non-typable H. influenzae pathogenicity should facilitate development of novel approaches to the treatment and prevention of H. influenzae disease.


Asunto(s)
Infecciones por Haemophilus/microbiología , Haemophilus influenzae/patogenicidad , Adhesinas Bacterianas/genética , Adhesinas Bacterianas/metabolismo , Animales , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Proteínas Bacterianas/genética , Fimbrias Bacterianas/genética , Fimbrias Bacterianas/metabolismo , Infecciones por Haemophilus/epidemiología , Haemophilus influenzae/química , Hemo/metabolismo , Humanos , Inmunidad Mucosa , Hierro/metabolismo , Mucosa Laríngea/microbiología , Proteínas de la Membrana/genética , Depuración Mucociliar , Mucosa Nasal/microbiología , Serina Endopeptidasas/metabolismo
18.
Gene ; 177(1-2): 23-8, 1996 Oct 24.
Artículo en Inglés | MEDLINE | ID: mdl-8921840

RESUMEN

The uvrA gene Haemophilus influenzae (Hi) was cloned and sequenced. Analysis of the deduced amino acid sequence revealed 81% identity and 90% similarity with the Escherichia coli UvrA protein. Consistent with a role of Hi uvrA in DNA repair, a Hi uvrA mutant exhibited increased sensitivity of UV irradiation. Furthermore, Hi uvrA was able to complement a mutation in the E. coli uvrA locus.


Asunto(s)
Adenosina Trifosfatasas/genética , Proteínas Bacterianas/genética , Proteínas de Unión al ADN/genética , Proteínas de Escherichia coli , Genes Bacterianos , Haemophilus influenzae/genética , Secuencia de Aminoácidos , Secuencia de Bases , Clonación Molecular , Reparación del ADN , ADN Bacteriano , Prueba de Complementación Genética , Haemophilus influenzae/enzimología , Haemophilus influenzae/efectos de la radiación , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Rayos Ultravioleta
19.
Microbes Infect ; 2(9): 1061-72, 2000 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10967286

RESUMEN

Secretion of proteins by the general secretory pathway (GSP) is a two-step process requiring the Sec translocase in the inner membrane and a separate substrate-specific secretion apparatus for translocation across the outer membrane. Gram-negative bacteria with pathogenic potential use the GSP to deliver virulence factors into the extracellular environment for interaction with the host. Well-studied examples of virulence determinants using the GSP for secretion include extracellular toxins, pili, curli, autotransporters, and crystaline S-layers. This article reviews our current understanding of the GSP and discusses examples of terminal branches of the GSP which are utilized by factors implicated in bacterial virulence.


Asunto(s)
Proteínas de la Membrana Bacteriana Externa/metabolismo , Proteínas Bacterianas , Proteínas de Escherichia coli , Bacterias Gramnegativas/metabolismo , Proteínas de Transporte de Membrana , Adenosina Trifosfatasas/metabolismo , Toxinas Bacterianas/metabolismo , Transporte Biológico , Proteínas Portadoras/metabolismo , Fimbrias Bacterianas/metabolismo , Glicósido Hidrolasas/metabolismo , Bacterias Gramnegativas/patogenicidad , Chaperonas Moleculares/metabolismo , Canales de Translocación SEC , Proteína SecA , Relación Estructura-Actividad , Virulencia
20.
Mol Cell ; 2(6): 841-50, 1998 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-9885571

RESUMEN

Haemophilus influenzae initiates infection by colonizing the upper respiratory mucosa. The process of colonization involves adherence to epithelium and evasion of host immunity. In this study, we examined the H. influenzae Hap adhesin, which has serine protease activity and undergoes autoproteolytic cleavage and extracellular release in broth. We found that the uncleaved cell-associated form of Hap mediates adherence to cultured epithelial cells and promotes bacterial aggregation and microcolony formation. Adherence and aggregation are augmented by secretory leukocyte protease inhibitor, a natural component of respiratory secretions that inhibits Hap autoproteolysis. These observations suggest a novel paradigm in host-pathogen relations, in which a soluble host protein whose primary function is to protect host epithelium potentiates properties that facilitate bacterial colonization.


Asunto(s)
Adhesión Bacteriana/fisiología , Proteínas de la Membrana Bacteriana Externa/fisiología , Haemophilus influenzae/enzimología , Proteínas/fisiología , Serina Endopeptidasas/fisiología , Proteínas de la Membrana Bacteriana Externa/genética , Proteínas de la Membrana Bacteriana Externa/metabolismo , Sitios de Unión , Recuento de Colonia Microbiana , Haemophilus influenzae/crecimiento & desarrollo , Haemophilus influenzae/patogenicidad , Humanos , Hidrólisis , Microscopía Electrónica de Rastreo , Mutación , Proteínas Inhibidoras de Proteinasas Secretoras , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismo , Células Tumorales Cultivadas/citología , Células Tumorales Cultivadas/microbiología
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