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1.
BMC Health Serv Res ; 21(1): 943, 2021 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-34503503

RESUMO

BACKGROUND: The Gambia has one of the lowest survival rates for breast cancer in Africa. Contributing factors are late presentation, delays within the healthcare system, and decreased availability of resources. We aimed to characterize the capacity and geographic location of healthcare facilities in the country and calculate the proportion of the population with access to breast cancer care. METHODS: A facility-based assessment tool was administered to secondary and tertiary healthcare facilities and private medical centers and clinics in The Gambia. GPS coordinates were obtained, and proximity of service availability and population analysis were performed. Distance thresholds of 10, 20, and 45 km were chosen to determine access to screening, pathologic diagnosis, and surgical management. An additional population analysis was performed to observe the potential impact of targeted development of resources for breast cancer care. RESULTS: All 102 secondary and tertiary healthcare facilities and private medical centers and clinics in The Gambia were included. Breast cancer screening is mainly performed through clinical breast examination and is available in 52 facilities. Seven facilities provide pathologic diagnosis and surgical management of breast cancer. The proportion of the Gambian population with access to screening, pathologic diagnosis, and surgical management is 72, 53, and 62%, respectively. A hypothetical targeted expansion of resources would increase the covered population to 95, 62, and 84%. CONCLUSIONS: Almost half of the Gambian population does not have access to pathologic diagnosis and surgical management of breast cancer within the distance threshold utilized in the study. Mapping and population analysis can identify areas for targeted development of resources to increase access to breast cancer care.


Assuntos
Neoplasias da Mama , Neoplasias da Mama/diagnóstico , Neoplasias da Mama/epidemiologia , Neoplasias da Mama/terapia , Estudos Transversais , Detecção Precoce de Câncer , Feminino , Gâmbia/epidemiologia , Acesso aos Serviços de Saúde , Humanos , Programas de Rastreamento
2.
Am J Trop Med Hyg ; 103(2): 696-703, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32458777

RESUMO

Despite the implementation of effective conjugate vaccines against the three main bacterial pathogens that cause meningitis, Streptococcus pneumoniae, Haemophilus influenzae type b (Hib), and Neisseria meningitidis serogroup A, the burden of meningitis in West Africa remains high. The relative importance of other bacterial, viral, and parasitic pathogens in central nervous system infections is poorly characterized. Cerebrospinal fluid (CSF) specimens were collected from children younger than 5 years with suspected meningitis, presenting at pediatric teaching hospitals across West Africa in five countries including Senegal, Ghana, Togo, Nigeria, and Niger. Cerebrospinal fluid specimens were initially tested using bacteriologic culture and a triplex real-time polymerase chain reaction (PCR) assay for N. meningitidis, S. pneumoniae, and H. influenzae used in routine meningitis surveillance. A custom TaqMan Array Card (TAC) assay was later used to detect 35 pathogens including 15 bacteria, 17 viruses, one fungus, and two protozoans. Among 711 CSF specimens tested, the pathogen positivity rates were 2% and 20% by the triplex real-time PCR (three pathogens) and TAC (35 pathogens), respectively. TAC detected 10 bacterial pathogens, eight viral pathogens, and Plasmodium. Overall, Escherichia coli was the most prevalent (4.8%), followed by S. pneumoniae (3.5%) and Plasmodium (3.5%). Multiple pathogens were detected in 4.4% of the specimens. Children with human immunodeficiency virus (HIV) and Plasmodium detected in CSF had high mortality. Among 220 neonates, 17% had at least one pathogen detected, dominated by gram-negative bacteria. The meningitis TAC enhanced the detection of pathogens in children with meningitis and may be useful for case-based meningitis surveillance.


Assuntos
Infecções por Escherichia coli/epidemiologia , Malária Cerebral/epidemiologia , Meningite Pneumocócica/epidemiologia , Meningite/epidemiologia , Meningite/microbiologia , África Ocidental/epidemiologia , Pré-Escolar , Técnicas de Cultura , Infecções por Citomegalovirus/líquido cefalorraquidiano , Infecções por Citomegalovirus/diagnóstico , Infecções por Citomegalovirus/epidemiologia , Infecções por Escherichia coli/líquido cefalorraquidiano , Infecções por Escherichia coli/diagnóstico , Feminino , Gana/epidemiologia , Infecções por HIV/líquido cefalorraquidiano , Infecções por HIV/diagnóstico , Infecções por HIV/epidemiologia , Vacinas Anti-Haemophilus/uso terapêutico , Humanos , Lactente , Recém-Nascido , Infecções por Klebsiella/líquido cefalorraquidiano , Infecções por Klebsiella/diagnóstico , Infecções por Klebsiella/epidemiologia , Malária Cerebral/líquido cefalorraquidiano , Malária Cerebral/diagnóstico , Masculino , Meningite/líquido cefalorraquidiano , Meningite/diagnóstico , Meningite por Haemophilus/líquido cefalorraquidiano , Meningite por Haemophilus/epidemiologia , Meningite por Haemophilus/prevenção & controle , Meningite Meningocócica/líquido cefalorraquidiano , Meningite Meningocócica/epidemiologia , Meningite Meningocócica/prevenção & controle , Meningite Pneumocócica/líquido cefalorraquidiano , Meningite Pneumocócica/prevenção & controle , Vacinas Meningocócicas/uso terapêutico , Técnicas de Diagnóstico Molecular , Mortalidade , Reação em Cadeia da Polimerase Multiplex , Níger/epidemiologia , Nigéria/epidemiologia , Vacinas Pneumocócicas/uso terapêutico , Reação em Cadeia da Polimerase em Tempo Real , Infecções por Roseolovirus/líquido cefalorraquidiano , Infecções por Roseolovirus/diagnóstico , Infecções por Roseolovirus/epidemiologia , Senegal/epidemiologia , Infecções Estafilocócicas/líquido cefalorraquidiano , Infecções Estafilocócicas/diagnóstico , Infecções Estafilocócicas/epidemiologia , Togo/epidemiologia
3.
PLoS Med ; 16(8): e1002870, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31408467

RESUMO

BACKGROUND: Infant DNA methylation profiles are associated with their mother's periconceptional nutritional status. DNA methylation relies on nutritional inputs for one-carbon metabolic pathways, including the efficient recycling of homocysteine. This randomised controlled trial in nonpregnant women in rural Gambia tests the efficacy of a novel nutritional supplement designed to improve one-carbon-related nutrient status by reducing plasma homocysteine, and assesses its potential future use in preconception trials. METHODS AND FINDINGS: We designed a novel drink powder based on determinants of plasma homocysteine in the target population and tested it in a three-arm, randomised, controlled trial. Nonpregnant women aged between 18 and 45 from the West Kiang region of The Gambia were randomised in a 1:1:1 allocation to 12 weeks daily supplementation of either (a) a novel drink powder (4 g betaine, 800 µg folic acid, 5.2 µg vitamin B12, and 2.8 mg vitamin B2), (b) a widely used multiple micronutrient tablet (United Nations Multiple Micronutrient Preparation [UNIMMAP]) containing 15 micronutrients, or (c) no intervention. The trial was conducted between March and July 2018. Supplementation was observed daily. Fasted venepuncture samples were collected at baseline, midline (week 5), and endline (week 12) to measure plasma homocysteine. We used linear regression models to determine the difference in homocysteine between pairs of trial arms at midline and endline, adjusted for baseline homocysteine, age, and body mass index (BMI). Blood pressure and pulse were measured as secondary outcomes. Two hundred and ninety-eight eligible women were enrolled and randomised. Compliance was >97.8% for both interventions. At endline (our primary endpoint), the drink powder and UNIMMAP reduced mean plasma homocysteine by 23.6% (-29.5 to -17.1) and 15.5% (-21.2 to -9.4), respectively (both p < 0.001), compared with the controls. Compared with UNIMMAP, the drink powder reduced mean homocysteine by 8.8% (-15.8 to -1.2; p = 0.025). The effects were stronger at midline. There was no effect of either intervention on blood pressure or pulse compared with the control at endline. Self-reported adverse events (AEs) were similar in both intervention arms. There were two serious AEs reported over the trial duration, both in the drink powder arm, but judged to be unrelated to the intervention. Limitations of the study include the use of a single targeted metabolic outcome, homocysteine. CONCLUSIONS: The trial confirms that dietary supplements can influence metabolic pathways that we have shown in previous studies to predict offspring DNA methylation. Both supplements reduced homocysteine effectively and remain potential candidates for future epigenetic trials in pregnancy in rural Gambia. TRIAL REGISTRATION: Clinicaltrials.gov Reference NCT03431597.


Assuntos
Suplementos Nutricionais , Homocisteína/sangue , Adolescente , Adulto , Betaína/administração & dosagem , Betaína/uso terapêutico , Feminino , Ácido Fólico/administração & dosagem , Ácido Fólico/uso terapêutico , Gâmbia , Homocisteína/antagonistas & inibidores , Humanos , Pessoa de Meia-Idade , Estado Nutricional , Riboflavina/administração & dosagem , Riboflavina/uso terapêutico , Vitamina B 12/administração & dosagem , Vitamina B 12/uso terapêutico , Adulto Jovem
4.
Lancet Respir Med ; 7(8): 665-676, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31235405

RESUMO

BACKGROUND: The efficacy and effectiveness of the pandemic H1N1 (pH1N1) component in live attenuated influenza vaccine (LAIV) is poor. The reasons for this paucity are unclear but could be due to impaired replicative fitness of pH1N1 A/California/07/2009-like (Cal09) strains. We assessed whether an updated pH1N1 strain in the Russian-backbone trivalent LAIV resulted in greater shedding and immunogenicity compared with LAIV with Cal09. METHODS: We did an open-label, prospective, observational, phase 4 study in Sukuta, a periurban area in The Gambia. We enrolled children aged 24-59 months who were clinically well. Children received one dose of the WHO prequalified Russian-backbone trivalent LAIV containing either A/17/California/2009/38 (Cal09) or A/17/New York/15/5364 (NY15) based on their year of enrolment. Primary outcomes were the percentage of children with LAIV strain shedding at day 2 and day 7, haemagglutinin inhibition seroconversion, and an increase in influenza haemagglutinin-specific IgA and T-cell responses at day 21 after LAIV. This study is nested within a randomised controlled trial investigating LAIV-microbiome interactions (NCT02972957). FINDINGS: Between Feb 8, 2017, and April 12, 2017, 118 children were enrolled and received one dose of the Cal09 LAIV from 2016-17. Between Jan 15, 2018, and March 28, 2018, a separate cohort of 135 children were enrolled and received one dose of the NY15 LAIV from 2017-18, of whom 126 children completed the study. Cal09 showed impaired pH1N1 nasopharyngeal shedding (16 of 118 children [14%, 95% CI 8·0-21·1] with shedding at day 2 after administration of LAIV) compared with H3N2 (54 of 118 [46%, 36·6-55·2]; p<0·0001) and influenza B (95 of 118 [81%, 72·2-87·2]; p<0·0001), along with suboptimal serum antibody (seroconversion in six of 118 [5%, 1·9-10·7]) and T-cell responses (CD4+ interferon γ-positive and/or CD4+ interleukin 2-positive responses in 45 of 111 [41%, 31·3-50·3]). After the switch to NY15, a significant increase in pH1N1 shedding was seen (80 of 126 children [63%, 95% CI 54·4-71·9]; p<0·0001 compared with Cal09), along with improvements in seroconversion (24 of 126 [19%, 13·2-26·8]; p=0·011) and influenza-specific CD4+ T-cell responses (73 of 111 [66%, 60·0-75·6; p=0·00028]). The improvement in pH1N1 seroconversion with NY15 was even greater in children who were seronegative at baseline (24 of 64 children [38%, 95% CI 26·7-49·8] vs six of 79 children with Cal09 [8%, 2·8-15·8]; p<0·0001). Persistent shedding to day 7 was independently associated with both seroconversion (odds ratio 12·69, 95% CI 4·1-43·6; p<0·0001) and CD4+ T-cell responses (odds ratio 7·83, 95% CI 2·99-23·5; p<0·0001) by multivariable logistic regression. INTERPRETATION: The pH1N1 component switch that took place between 2016 and 2018 might have overcome the poor efficacy and effectiveness reported with previous LAIV formulations. LAIV effectiveness against pH1N1 should, therefore, improve in upcoming influenza seasons. Our data highlight the importance of assessing replicative fitness, in addition to antigenicity, when selecting annual LAIV components. FUNDING: The Wellcome Trust.


Assuntos
Vírus da Influenza A Subtipo H1N1/efeitos dos fármacos , Vírus da Influenza A Subtipo H1N1/imunologia , Vacinas contra Influenza/imunologia , Vacinas contra Influenza/uso terapêutico , Influenza Humana/prevenção & controle , Eliminação de Partículas Virais/efeitos dos fármacos , Pré-Escolar , Feminino , Gâmbia , Humanos , Influenza Humana/imunologia , Masculino , Pandemias , Estudos Prospectivos , Resultado do Tratamento , Vacinas Atenuadas , Eliminação de Partículas Virais/imunologia
5.
BMJ Open ; 8(4): e018341, 2018 04 12.
Artigo em Inglês | MEDLINE | ID: mdl-29654005

RESUMO

OBJECTIVES: Air pollution has been associated with increased mortality and morbidity in several studies with indications that its effect could be more severe in children. This study examined the relationship between short-term variations in criteria air pollutants and occurrence of sudden infant death syndrome (SIDS). DESIGN: We used a case-crossover study design which is widely applied in air pollution studies and particularly useful for estimating the risk of a rare acute outcome associated with short-term exposure. SETTING: The study used data from the West Midlands region in the UK. PARTICIPANTS: We obtained daily time series data on SIDS mortality (ICD-9: 798.0 or ICD-10: R95) for the period 1996-2006 with a total of 211 SIDS events. PRIMARY OUTCOME MEASURES: Daily counts of SIDS events. RESULTS: For an IQR increase in previous day pollutant concentration, the percentage increases (95% CI) in SIDS were 16 (6 to 27) for PM10, 1 (-7 to 10) for SO2, 5 (-4 to 14) for CO, -17 (-27 to -6) for O3, 16 (2 to 31) for NO2 and 2 (-3 to 8) for NO after controlling for average temperature and national holidays. PM10 and NO2 showed relatively consistent association which persisted across different lag structures and after adjusting for copollutants. CONCLUSIONS: The results indicated ambient air pollutants, particularly PM10 and NO2, may show an association with increased SIDS mortality. Thus, future studies are recommended to understand possible mechanistic explanations on the role of air pollution on SIDS incidence and the ways in which we might reduce pollution exposure among infants.


Assuntos
Poluição do Ar/efeitos adversos , Morte Súbita do Lactente/epidemiologia , Morte Súbita do Lactente/etiologia , Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/estatística & dados numéricos , Criança , Estudos Cross-Over , Humanos , Lactente , Material Particulado/efeitos adversos , Reino Unido/epidemiologia , População Urbana
6.
Gates Open Res ; 2: 48, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30569038

RESUMO

Background: Iron deficiency and its associated anaemia (IDA) are the leading forms of micronutrient malnutrition worldwide. Here we describe the rationale and design of the first clinical trial evaluating the efficacy and safety of an innovative nano iron supplement, iron hydroxide adipate tartrate (IHAT), for the treatment of IDA in young children (IHAT-GUT trial). Oral iron is often ineffective due to poor absorption and/or gastrointestinal adverse effects. IHAT is novel since it is effectively absorbed whilst remaining nanoparticulate in the gut, therefore should enable supplementation with fewer symptoms. Methods: IHAT-GUT is a three-arm, double-blind, randomised, placebo-controlled phase II trial conducted in Gambian children 6-35 months of age. The intervention consists of a 12-week supplementation with either IHAT, ferrous sulphate (both at doses bioequivalent to 12.5 mg Fe/day) or placebo. The trial aims to include 705 children with IDA who will be randomly assigned (1:1:1) to each arm. The primary objectives are to test non-inferiority of IHAT in relation to ferrous sulphate at treating IDA, and to test superiority of IHAT in relation to ferrous sulphate and non-inferiority in relation to placebo in terms of diarrhoea incidence and prevalence. Secondary objectives are mechanistic assessments, to test whether IHAT reduces the burden of enteric pathogens, morbidity, and intestinal inflammation, and that it does not cause detrimental changes to the gut microbiome, particularly in relation to Lactobacillaceae, Bifidobacteriaceae and Enterobacteriaceae. Discussion: This trial will test the hypothesis that supplementation with IHAT eliminates iron deficiency and improves haemoglobin levels without inducing gastrointestinal adverse effects. If shown to be the case, this would open the possibility for further testing and use of IHAT as a novel iron source for micronutrient intervention strategies in resource-poor countries, with the ultimate aim to help reduce the IDA global burden. Registration: This trial is registered at clinicaltrials.gov ( NCT02941081).

7.
J Immunol Methods ; 449: 1-6, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28647455

RESUMO

We need greater understanding of the mechanisms underlying protection against influenza virus to develop more effective vaccines. To do this, we need better, more reproducible methods of sampling the nasal mucosa. The aim of the current study was to compare levels of influenza virus A subtype-specific IgA collected using three different methods of nasal sampling. Samples were collected from healthy adult volunteers before and after LAIV immunization by nasal wash, flocked swabs and Synthetic Absorptive Matrix (SAM) strips. Influenza A virus subtype-specific IgA levels were measured by haemagglutinin binding ELISA or haemagglutinin binding microarray and the functional response was assessed by microneutralization. Nasosorption using SAM strips lead to the recovery of a more concentrated sample of material, with a significantly higher level of total and influenza H1-specific IgA. However, an equivalent percentage of specific IgA was observed with all sampling methods when normalized to the total IgA. Responses measured using a recently developed antibody microarray platform, which allows evaluation of binding to multiple influenza strains simultaneously with small sample volumes, were compared to ELISA. There was a good correlation between ELISA and microarray values. Material recovered from SAM strips was weakly neutralizing when used in an in vitro assay, with a modest correlation between the level of IgA measured by ELISA and neutralization, but a greater correlation between microarray-measured IgA and neutralizing activity. In conclusion we have tested three different methods of nasal sampling and show that flocked swabs and novel SAM strips are appropriate alternatives to traditional nasal washes for assessment of mucosal influenza humoral immunity.


Assuntos
Anticorpos Antivirais/análise , Imunoglobulina A/análise , Vírus da Influenza A/imunologia , Vacinas contra Influenza/imunologia , Mucosa Nasal/imunologia , Manejo de Espécimes/métodos , Adulto , Anticorpos Antivirais/imunologia , Ensaio de Imunoadsorção Enzimática/métodos , Feminino , Humanos , Imunidade nas Mucosas , Imunoglobulina A/imunologia , Masculino , Líquido da Lavagem Nasal/imunologia , Mucosa Nasal/virologia , Análise Serial de Proteínas , Manejo de Espécimes/instrumentação
8.
Artigo em Inglês | MEDLINE | ID: mdl-27294948

RESUMO

Some in vitro studies have indicated a possible link between respiratory syncytial virus (RSV) infection and exposure to Nitric Oxide (NO). However, these studies used much higher NO concentrations than normally found in the ambient environment. This preliminary study explored whether an association was present with short-term exposure to NO in the environment. RSV-related admission data between November 2011 and February 2012 were obtained from Sheffield Children's Hospital. The dates of admission were linked to contemporaneous ambient NO derived from sentinel air monitors. The case-crossover design was used to study the relationship between daily RSV admissions and NO, controlling for temperature and relative humidity. We found little evidence of association between daily RSV admission rates and exposure to ambient NO at different lags or average exposure across several lags. The findings should, however, be viewed with caution due to the low number of events observed during the time frame. It is possible that the apparent lack of association may be accounted for by the timing of the seasonal RSV epidemic in relation to peaks in NO concentrations. A larger study incorporating a wider range of RSV and NO peaks would determine whether said peaks enhanced the number of RSV hospitalizations in children.


Assuntos
Poluentes Atmosféricos/toxicidade , Bronquiolite/epidemiologia , Hospitalização/estatística & dados numéricos , Óxido Nítrico/toxicidade , Infecções por Vírus Respiratório Sincicial/epidemiologia , Criança , Pré-Escolar , Exposição Ambiental/efeitos adversos , Feminino , Hospitais Pediátricos/estatística & dados numéricos , Humanos , Lactente , Masculino
9.
Trop Med Int Health ; 19(3): 275-283, 2014 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-24393095

RESUMO

OBJECTIVE: To establish haematological and biological reference values for Gambian infants. METHODS: Basic haematological and biochemical indices were analysed in blood samples obtained from healthy infants from Sukuta in the Western Division of The Gambia. The 2.5 and the 97.5 centiles for these indices were estimated. RESULTS: Reference ranges for haematological and biochemical indices were determined. Haemoglobin, total white cell count (WBC) and platelet levels decreased with age (P < 0.001), whereas most of the white cell count subsets except monocytes did not vary with age. Potassium and alkaline phosphatase fell significantly with increasing age (P < 0.001; P < 0.001), whereas urea and creatinine rose with increasing age (P = 0.002; P < 0.001, respectively). CONCLUSION: Our set of haematological and biochemical reference values for healthy infants in The Gambia differs from values in other settings, thus underscoring the importance of establishing region-specific paediatric reference ranges to ensure optimal patient management and evaluate the impact of interventions in clinical research.


Assuntos
Grupo com Ancestrais do Continente Africano , Desenvolvimento Infantil/fisiologia , Testes Hematológicos/normas , Distribuição por Idade , Fosfatase Alcalina/sangue , Estatura/fisiologia , Peso Corporal/fisiologia , Creatinina/sangue , Feminino , Gâmbia , Testes Hematológicos/métodos , Testes Hematológicos/estatística & dados numéricos , Hemoglobinas/análise , Humanos , Lactente , Modelos Lineares , Masculino , Desnutrição/sangue , Estado Nutricional/fisiologia , Potássio/sangue , Valores de Referência , Distribuição por Sexo , Estatística como Assunto , População Urbana/estatística & dados numéricos , Ureia/sangue
10.
PLoS Negl Trop Dis ; 5(5): e1148, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21655353

RESUMO

BACKGROUND: Non-Typhoidal Salmonella (NTS) is an important cause of invasive bacterial disease and associated with mortality in Africa. However, little is known about the environmental reservoirs and predominant modes of transmission. Our study aimed to study the role of domestic animals in the transmission of NTS to humans in rural area of The Gambia. METHODOLOGY: Human NTS isolates were obtained through an active population-based case-control surveillance study designated to determine the aetiology and epidemiology of enteric infections covering 27,567 Gambian children less than five years of age in the surveillance area. Fourteen children infected with NTS were traced back to their family compounds and anal swabs collected from 210 domestic animals present in their households. Identified NTSs were serotyped and genotyped by multi-locus sequencing typing. PRINCIPAL FINDINGS: NTS was identified from 21/210 animal sources in the households of the 14 infected children. Chickens carried NTS more frequently than sheep and goats; 66.6%, 28.6% and 4.8% respectively. The most common NTS serovars were S. Colindale in humans (21.42%) and S. Poona in animals (14.28%). MLST on the 35 NTS revealed four new alleles and 24 sequence types (ST) of which 18 (75%) STs were novel. There was no overlap in serovars or genotypes of NTS recovered from humans or animal sources in the same household. CONCLUSION: Our results do not support the hypothesis that humans and animals in close contact in the same household carry genotypically similar Salmonella serovars. These findings form an important baseline for future studies of transmission of NTS in humans and animals in Africa.


Assuntos
Tipagem Molecular , Salmonelose Animal/microbiologia , Infecções por Salmonella/microbiologia , Salmonella/classificação , Salmonella/isolamento & purificação , Animais , Animais Domésticos , Pré-Escolar , Análise por Conglomerados , Feminino , Gâmbia , Genótipo , Humanos , Lactente , Masculino , Epidemiologia Molecular , Fenótipo , População Rural , Salmonella/genética , Sorotipagem
11.
BMC Clin Pathol ; 11: 2, 2011 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-21261963

RESUMO

BACKGROUND: Frozen storage often precedes metagenomic analysis of biological samples; however, the freezing process can have adverse effects on microbial composition. The effect of freezing on the detection of bacteria inhabiting the infant nasopharynx, a major reservoir of bacterial pathogens, was investigated. METHODS: 16S ribosomal RNA (rRNA) gene-based terminal restriction fragment length polymorphism (T-RFLP) analysis of nasopharyngeal (NP) swabs from twelve Gambian infants was employed. NP swabs were analysed within hours of collection and then after 30 days of storage at -70°C. RESULTS: There was substantial heterogeneity among subjects with respect to the effect of freezing on the number of operational taxonomic units (OTUs) detected. Nevertheless, the mean number of OTUs decreased after frozen storage and the relative abundance for 72% of the OTUs changed by less than 0.5% after deep frozen storage. There were differences in the odds of detection and relative abundance of OTUs matched with Moraxella sp., Haemophilus sp./Burkholderia sp., and Pseudomonas sp. A strong interaction between sex and the effect of freezing was found, whereby there was no significant change observed for males while the mean number of OTUs significantly declined among female infants following frozen storage. CONCLUSIONS: Although frozen storage of biological samples is often necessary for archiving and logistic purposes, the potential effects on the number of taxa (composition) detected in microbial community studies are significant and should not be overlooked. Moreover, genetic factors such as sex may influence the integrity of nucleic acids during the freezing process.

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