Molecular biomarkers to assess health risks due to environmental contaminants exposure / Biomarcadores moleculares para evaluar el riesgo para la salud debido a la exposición a contaminantes ambientales

Biomarkers, or bioindicators, are metric tools that, when compared with reference values, allow specialists to perform risk assessments and provide objective information to decision makers to design effective strategies to solve health or environmental problems by efficiently using the resources assigned. Health risk assessment is a multidisciplinary exercise, and molecular biology is a discipline that greatly contributes to these evaluations because the genome, transcriptome, proteome and metabolome could be affected by xenobiotics causing measurable changes that might be useful biomarkers. Such changes may greatly depend on individual genetic background; therefore, the polymorphic distribution of exposed populations becomes an essential feature for adequate data interpretation. The aim of this paper is to offer an up-to-date review of the role of different molecular biomarkers in health risk assessments.

Los biomarcadores, o bioindicadores, son herramientas métricas que, al compararse con los valores de referencia, permiten evaluar los riesgos y generar información objetiva que ayude a las autoridades a planificar estrategias efectivas, solucionar problemas de salud o ambientales y utilizar los recursos asignados de manera eficiente. La evaluación de riesgos en salud es un ejercicio multidisciplinario y la biología molecular contribuye enormemente a estos estudios, dado que el genoma, el transcriptoma, el proteoma y el metaboloma pueden verse afectados por xenobióticos, lo que causa cambios cuya medición resulta útil en la adopción de decisiones. Dichos cambios pueden variar por la carga genética de cada individuo y su distribución polimorfa en las poblaciones expuestas se convierte en un factor esencial para una adecuada interpretación de resultados. Por lo tanto, el objetivo del presente artículo fue hacer una revisión de los diferentes biomarcadores moleculares aplicables a la evaluación de riesgos para la salud provenientes de los contaminantes ambientales.

Avaliação dos fenótipos de acetilação e hidroxilação predominantes nas populações de cinco macrorregiões do Brasil baseada no genoma: possível influência da farmacogenética na conduta terapêutica da hanseníase / Evaluation of acetylation and hydroxylation phenotypes predominant in the populationsof five geographical regions of Brazil based on the genome: possible influence ofpharmacogenetics in the therapeutic management of leprosy

A hanseníase é uma doença infecciosa crônica, com alto poder incapacitante. O tratamento sebaseia na combinação de três drogas: dapsona, rifampicina e clofazimina, porém, a ocorrênciade reações adversas (ADRs) induzidas principalmente pela dapsona (~70%) é frequentementeobservada. Dentre as ADRs destacam-se: a metemoglobinemia, anemia hemolítica, a hepatitee a síndrome da dapsona. A metabolização da dapsona é baseada em reações enzimáticas deacetilação e hidroxilação, catalisadas, pelas enzimas N-acetiltransferase2 (NAT2) ehidroxilases do citocromo P450 (CYPs). Dentre os vários fatores associados à ocorrência deADRs, o fator genético é primordial. Polimorfismos presentes em genes que codificam paraenzimas metabolizadoras de drogas podem representar alto risco para este desfecho.Paralelamente, outro aspecto importante é a alta variabilidade genética ligada à etnia. O Brasilé um país composto por uma população altamente miscigenada com alta diversidade genética.Sendo a hanseníase uma doença endêmica tratada com um esquema padronizado para toda apopulação, a avaliação destes perfis genéticos é de fundamental relevância para a prevençãode ADRs. Este estudo teve como principal objetivo descrever a variabilidade dos genes NAT2,CYP2E1, CYP3A4 e CYP3A5 em coortes de pacientes de hanseníase provenientes das cincodiferentes macrorregiões do Brasil e realizar um estudo de associação, do tipo caso-controle,entre as variáveis genéticas presentes nesses genes com a ocorrência de reações adversas empacientes com hanseníase em tratamento com esquemas contendo dapsona. Um total de 964indivíduos foram incluidos no estudo descritivo de NAT2 enquanto para o estudo deassociação variou dependendo da região. Vinte e três SNPs de NAT2, foram identificadosnas populações estudadas, dos quais sete: 191 G>A; 282 C>T; 341T>C; 481 C>T; 590 G>A;803 A>G e 857 G>A, são os mais frequentes na população mundial...

Leprosy is a chronic infectious disease with high disabling potential. The treatment is basedon the combination of three drugs: dapsone, rifampicin and clofazimine, however, theoccurrence of adverse drug reactions (ADRs) mainly induced by dapsone (~70%) isfrequently observed with a predominance of methemoglobinemia, hemolytic anemia, hepatitisand dapsone syndrome. The dapsone metabolization is mediated by acetylation andhydroxylation enzymatic reactions catalyzed by the N-acetyltransferase 2 (NAT2) andcytochrome P450 (CYPs). Among the various factors associated with the occurrence ofADRs, the genetic factor is essential. Polymorphisms in genes encoding drug metabolizingenzymes may represent a high risk for this outcome. In paralell, another important aspect isthe high genetic variability related to ethnicity. Brazil is composed of a high mixed populationwith high levels of genetic diversity. Being leprosy is an endemic disease which treatment isa standard regimen for the entire population, the evaluation of these genetic profiles becamerelevant for prevention of ADRs. The main goals of this study was to describe the geneticvariability of NAT2, CYP2E1, CYP3A4 and CYP3A5 in cohorts of leprosy patients from fiveBrazilian geographical regions and to perform an association study (case-control) between thegenetic variants present in these genes and occurrence of ADRs in leprosy patients treatedwith dapsone-containing schemes. A total of 964 individuals were enrolled to the descriptivestudy for NAT2 while for the association study the sample size varied according to theregion.Twenty-three SNPs in NAT2, were identified in the study populatuion, seven of which191 G> A; 282 C> T; 341T> C; 481 C> T; 590 G> A; 803 A> G and 857 G>A are the mostfrequent in the world population...

Efeito da vacina pneumocócica 10-valente em eventos de colonização nasofaríngea em crianças na cidade de Salvador-Bahia / Effect of pneumococcal 10-valent in nasopharyngeal colonization events in children in the city of Salvador, Bahia

Streptococcus pneumoniae é uma bactéria patogênica que afeta crianças e idosos em todo o mundo, sendo responsável por elevada morbidade e mortalidade, especialmente nos países em desenvolvimento onde o acesso às vacinas pneumocócicas conjugadas (PCVs) é limitado. A colonização da nasofaringe precede o desenvolvimento de infecções e as crianças são o principal reservatório deste patógeno na comunidade. As vacinas pneumocócicas conjugadas reduzem a taxa de colonização e de doenças causadas por sorotipos vacinais, entretanto, pouco se sabe sobre seu efeito em eventos na substituição de sorotipos. Os objetivos deste estudo foram determinar o efeito da vacina pneumocócica conjugada 10-valente (PCV10) na colonização nasofaríngea por pneumococos em crianças menores que um ano, saudáveis e que apresentaram doença crônica ou desordem imunológica nos períodos pré- e pós esquema vacinal primário entre maio de 2011 a janeiro de 2014 e determinar a influência desta vacina na distribuição de sorotipos, da susceptibilidade antimicrobiana e do perfil genotípico dos pneumococos. Foram investigadas 168 crianças, sendo 63 do grupo de portadores de doenças clínicas (Grupo I) e 105 do grupo de crianças sadias (Grupo II). O isolamento, a identificação e a avaliação da resistência antimicrobiana do pneumococo foram realizados através de técnicas microbiológicas convencionais. A determinação dos sorotipos capsulares foi realizada através das técnicas de reação de polimerase em cadeia multiplex e reação de Quellung. A taxa de colonização pneumocócica total foi de 24%, sendo 17% (11/63) e 28% (29/105) para os grupos I e II, respectivamente...

Streptococcus pneumoniae is a pathogenic bacterium that affects children and elderly throughout the world, accounting for high morbidity and mortality, especially in developing countries where acess to pneumococcal conjugate vaccines (PCVs) is limited. Nasopharyngeal colonization precedes the development of infections and children are the main reservoir of this pathogen in the community. The pneumococcal conjugate vaccine has been effective in reducing colonization and disease by vaccine serotypes, however, little is known about its effect on the overall rate of colonization due to serotypes replacement events. The study aims to evaluate the effect of pneumococcal conjugate vaccine on nasopharyngeal carriage in children younger than one years old, healthy, suffering from crhonic diseases or immune disorders during vaccine primary immunization with PCV-10 between may 2011 and jaanuary 2014 and the influence of this vaccine in the distribution of serotypes, antimicrobial susceptibility and genotypic profile of pneumococcus. A total of 168 children were enrolled, 63 with chronic diseases (Group I) and 105 of the group of healthy children (Group II). The isolation, identification and evaluation of antimicrobial resistance of pneumococci were made using conventional microbiological techniques. The determination of capsular serotypes was performed using the multiplex-PCR and/or Quellung reaction. Overal, the pneumococcal colonization rate was 24%, being 17% (11/63) and 28% (29/105) to group I and II, respectively...

Community-associated methicillin-resistant Staphylococcus aureus in non-outbreak skin infections

The aim of this study was to determine the prevalence of Staphylococcus aureus and risk factors for the acquisition of MRSA (Methicillin Resistant Staphylococcus aureus) as the main cause of skin and soft tissue infections. S. aureus were characterized for the presence of PVL, TSST-1 and mecA genes. SCCmec typing was carried out in mecA positive strains and PFGE was performed only in these strains. During the study period, 127 outpatients attending a dermatology clinical the Botucatu Medical School, a regional tertiary hospital in Botucatu, Sao Paulo, Brazil, were diagnosed with active skin infections. A total 66 (56.9%) S. aureus strains were isolated. The methicillin resistance gene mecA was detected in seven (10.6%) S. aureus strains. The SCCmec types detected in the seven mecA-positive S. aureus strains were type Ia in one, type II in three, and type IV in three. The PVL gene was detected in 10 (15.1%) in sensitive strains. Pulsed field gel electrophoresis revealed non-clonal diversity among the isolates. The risk factors associated with MRSA acquisition in this study were previous ciprofloxacin use and working in a healthcare environment. The risk factors indicate plausible routes of CA-MRSA transmission among the subjects studied.

Correlations between major risk factors and closely related Mycobacterium tuberculosis isolates grouped by three current enotyping procedures: a population-based study in northeast Mexico

The characteristics of tuberculosis (TB) patients related to a chain of recent TB transmissions were investigated. Mycobacterium tuberculosis (MTB) isolates (120) were genotyped using the restriction fragment length polymorphism-IS6110 (R), spacer oligotyping (S) and mycobacterial interspersed repetitive units-variable number of tandem repeats (M) methods. The MTB isolates were clustered and the clusters were grouped according to the similarities of their genotypes. Spearman’s rank correlation coefficients between the groups of MTB isolates with similar genotypes and those patient characteristics indicating a risk for a pulmonary TB (PTB) chain transmission were ana- lysed. The isolates showing similar genotypes were distributed as follows: SMR (5%), SM (12.5%), SR (1.67%), MR (0%), S (46.67%), M (5%) and R (0%). The remaining 35 cases were orphans. SMR exhibited a significant correlation (p < 0.05) with visits to clinics, municipalities and comorbidities (primarily diabetes mellitus). S correlated with drug consumption and M with comorbidities. SMR is needed to identify a social network in metropolitan areas for PTB transmission and S and M are able to detect risk factors as secondary components of a transmission chain of TB.

Prevalência e fatores de risco para carreamento de Staphylococcus aureus resistente à meticilina em idosos institucionalizados na cidade de Bauru-SP / Prevalence and risk factors for Staphylococcus aureus carrying of methicillin resistant in institutionalized elderly in the city of Bauru- SP

O aumento recente da incidência e gravidade de Staphylococcus aureus tem suscitado diversos estudos abordando sua epidemiologia em instituições fechadas. Isolados de S. aureus resistentes à meticilina (methicillin resistant S. aureus, MRSA) são agentes comuns de infecção em hospitais. Nos últimos anos, a atenção dos epidemiologistas e clínicos tem se voltado aos MRSA de origem comunitária, associados a infecções graves de pele e trato respiratório. Nesse contexto, as Casas de repouso representam espaços de especial interesse, já que são instituições intermediárias entre a comunidade e os serviços de saúde. Não há dados sobre prevalência de S. aureus e MRSA em Casas de repouso no Brasil, um país onde somente 0,8% da população idosa são institucionalizadas. O presente estudo teve delineamento transversal e objetivou identificar a prevalência e fatores de risco para colonização por S. aureus como um todo e MRSA em particular. Foram incluídos 300 idosos vivendo em Casas de repouso no município de Bauru (SP). A colonização foi analisada através de coleta de swabs nasais dos sujeitos da pesquisa. Estes foram cultivados, e nos casos de isolamento de S. aureus, foi realizada a caracterização molecular da resistência à meticilina. Adicionalmente, os isolados de MRSA foram submetidos à genotipagem por Pulsed-Field Gel Electrophoresis (PFGE). Para análises de fatores de risco, foram levantados os prontuários dos sujeitos de pesquisa. Dados demográficos, internações, procedimentos e uso de antimicrobianos foram identificados. Análises univariadas e multivariadas (regressão logística) foram aplicadas. As prevalências identificadas para S. aureus e MRSA foram 17,7% e 3,7%, respectivamente. A idade avançada e a internação recente em hospitais foram preditores independentes para colonização por S. aureus como um todo...

The recent increase in the incidence and severity of Staphylococcus aureus gave rise to many studies on its epidemiology in closed institutions. Isolates of methicillin-resistant Staphylococcus aureus (MRSA) are usual agents of infection in hospitals. In recent years, the attention of epidemiologists and clinicians has turned to MRSA of community origin, associated with severe infections of skin and respiratory tract. In this context, nursing homes represent areas of special interest, since they are intermediary institutions between the community and health services. No data on the prevalence of S. aureus and MRSA in nursing homes in Brazil, a country where only 0.8% of the elderly population is institutionalized. This cross-sectional study aimed to identify the prevalence and risk factors for colonization by S. aureus as a whole and MRSA in particular. We enrolled 300 elderly living in nursing homes in the city of Bauru, São Paulo State, Brazil. Colonization was analyzed by collecting nasal swabs of research subjects. Whenever S. aureus was isolated, we performed molecular characterization of methicillin resistance. Additionally, MRSA isolates underwent genotyping by pulsed-field gel electrophoresis (PFGE). For analysis of risk factors, we reviewed the charts of research subjects. Demographics, hospitalizations, procedures and uses of antimicrobials were identified. Univariate and multivariate (logistic regression) were applied. The prevalence identified for S. aureus and MRSA were 17.7% and 3.7%, respectively. Old age and recent hospitalization in hospitals were independent predictors of colonization with S. aureus as a whole, while small or medium-sized facilities and recent hospital admission were associated with carriage of MRSA...

Estudo da virulência, adesão e características fenotípicas de isolados do complexo Sporothrix / Study of virulence, adhesion and phenotypic characteristics of isolates of Sporothrix complex

A esporotricose é uma doença micótica, infecciosa e crônica, que envolve o tecido cutâneo e subcutâneo, e que pode afetar seres humanos e animais. Esta micose sempre foi atribuída a um único patógeno, o Sporothrix schenckii, um fundo termodimórfico, que cresce como levedura a 37 oC e como micélio à temperatura ambiente. No entanto, nos últimos anos, foi demonstrado que isolados identificados como S. schenckii apresentavam grande variabilidade genética, sugerindo que esta táxon consiste em um complexo de espécies. Esta doença é causada pela implantação traumática do patógeno fúngico, porém os mecanismos de invasão e disseminação deste microorganismo, bem como as moléculas envolvidas nestes processos, ainda são pouco conhecidos. Com base nessas informações, este trabalho visa identificar moléculas de superfície deste patógeno envolvidas na interação deste fungo com proteínas matriciais, bem como analisar diferenças fenotípicas entre espécies do denominado complexo Sporothrix. Foram utilizados, neste estudo, cinco isolados de Sporothrix spp., sendo três isolados clínicos, um isolado ambiental e um isolado de gato. A virulência de cada isolado foi comparada à capacidade adesiva à proteína matricial fibronectina. Foi observado que os isolados com amior capacidade infectiva eram os que apresentavam maior capacidade adesiva à fibronectina. Verificamos então a expressão de adesinas para fibronectina na superfície de cada isolado, por Western blot, e observamos que os isolados mais virulentos e com maior capacidade adesiva expressavam mais adesinas para fibronectina. Bandas reativas com o anticorpo monoclonal contra adesina gp70 (mAb P6E7) foram reveladas nos extratos de parede celular dos isolados estudados. Análises por microscopia confocal revelaram a colocalização da gp70 com a adesina para fibronectina na superfície dos isolados. Análises filogenéticas demonstraram que os isolados estudados possuíam diferenças genotípicas capazes de agrupá-los em duas espécies...

Sporotrichosis is a chronic and infectious diseases that involves the cutaneous and subcutaneous tissue, which can affect humans and animals. This mycosis has always been attributed to a single pathogen, the Sporothrix schenckii, a dimorphic fungus, that grows as yeast at 37 oC and as mycelia at room temperature. However, in recent years, some isolates identifies as S. schenckii showed considerable genetic variability, sugesting that this taxon consists of a complex of species. This disease is caused by the traumatic inoculation of the fungal pathogen, however, the molecules involved in the invasion and dissemination of this microorganism are still poorly understood. The aim of this study is to identify surface molecules involved in the interaction of this fungus with extracellular matrix proteins and to examine phenotypic differences between species in the Sporothrix complex. Five isolates were used throughout this study, three clinical isolates, an environmental and one cat isolate. The virulence of each isolate was compared to the adhesive capacity to fibronectin. We observed that the most virulent isolates exhibited the higher capacity to interact with fibronectin. The expression of adhesins for fibronectin on the surface of each isolate was verified by Western blot. This analysis showed that the most virulent isolates expressed more fibronectin adhesins than the avirulent ones. Positive bands for the monoclonal antibody raised against gp70 adhesin (mAb P6E7) were revealed in cell wall extracts of the isolates studied. Confocal microscopy confirmed the colocalization of fibronectin and mAb P6E7 on the yeast cell surface. Molecular analysis showed genotypic differences between isolates used in this study, that can cluster than them into two species, S. schenckii and S. brasiliensis. This phylogenetic analysis revealed that the avirulent isolate was S. brasiliensis and not S. schenckii as previously thought. This new data led us o determine whether...

Os riscos genômicos e a responsabilidade pessoal em saúde / Genomic risk and personal responsibility in health

With the advent of genomic research, a new category of risk has emerged-genetic risk-from which an individual cannot be separated. Among the outcomes of this model is a discussion on personal accountability, according to which an individual may both be exempted from events related to certain states of health ("blame it on the genes") or be blamed for those events ("transmitter of disease"). In addition, the search for genes to explain disease erases the line between what is normal and what is pathological, with a growing tendency towards considering individuals with no or very mild clinical manifestations as being "ill." The great emphasis on genomics may lead to both an exaggerated attention to genetics rather than social and environmental factors and to a reductionism that favors sociobiological explanations for human behavior. In addition, in this scenario, the right to information may paradoxically stimulate some to consume goods and services in order to prevent a hypothetical illness that could occur at some point in time as a result of genetic predisposition-goods and services that may not be available to everyone. It is essential that such issues be considered with the same urgency with which the genomic paradigm is being developed.

Molecular epidemiology of HIV-1 in Rio Grande, RS, Brazil

We conducted a molecular epidemiological study to investigate HIV-1 strains in Rio Grande, southern Brazil, searching for an association with transmission mode and risk behavior. Patients (185) identified at an AIDS treatment reference Hospital, from 1994 to 1997, were included; from which 107 blood samples were obtained. Nested PCR was realized once for each sample; for amplified samples (69) HIV subtypes were classified using the heteroduplex mobility assay. Subtypes identified were B (75 percent), C (22 percent) and F (3 percent). All infections with C were diagnosed after 1994. Comparing patients with B and C, no differences were detected regarding demographic, clinical and laboratory characteristics; survival analysis did not reveal differences in HIV to AIDS evolution. A higher proportion of injecting drug users, IDU (not significant, p<.07) was found among those with C. This suggests that C may have been introduced in this area through IDU, and is being spread, probably by their sexual partners, to persons with other risk practices

Status of antituberculosis drug resistance in Saudi Arabia 1979-98

All published material on the prevalence of drug-resistant tuberculosis within Saudi Arabia over the period 1979-98 was reviewed. The prevalence of single-drug-resistant tuberculosis ranged from 3.4% to 41% for isoniazid, 0% to 23.4% for rifampicin, 0.7% to 22.7% for streptomycin and 0% to 6.9% for ethambutol. The prevalence of multidrug-resistant tuberculosis [defined by WHO as resist1qance to two or more first-line antituberculosis drugs] ranged from 1.5% to 44% in different regions. No strong conclusions could be drawn owing to variations in the populations studied, geographical origins, site of Mycobacterium tuberculosis isolation [pulmonary or extrapulmonary] and drug sensitivity testing. However, the need to develop a standardized national policy for surveillance of drug-resistant tuberculosis in Saudi Arabia is clear

Tendências da investigaçäo epidemiológica em doenças crônicas / Epidemiological research trends in chronic diseases

A identificaçäo de vários fatores de risco da vida adulta contribuiu, sobretudo nos países desenvolvidos, para a diminuiçäo da ocorrência de doenças cardiovasculares e de alguns tipos de câncer. O modelo etiológico mais adotado enfatiza no entanto, os fatores de risco relacionados ao estilo de vida e às exposiçöes ocupacionais. Esta ênfase vem levando a uma excessiva individualizaçäo do risco, com um conseqüente enfraquecimento do vínculo da epidemiologia com a saúde pública. Säo comentadas as opiniöes de epidemiologistas que fazem uma reflexäo sobre as falhas, os limites e os desdobramentos da epidemiologia moderna que têm contribuído para uma reorientaçäo teórica da disciplina. Identifica-se assim, que as alternativas ao modelo atual devem buscar uma integraçäo entre os achados de biologia molecular com os fatores de risco classicamente concebidos e com condiçöes adversas em etapas precoces da vida, considerando todas estas influências causais em níveis hierarquizados de organizaçäo. Säo destacadas e comentadas três importantes vertentes neste processo de evoluçäo: a epidemiologia molecular, a teoria dos eventos precoces na vida e os modelos multinível.

La epidemiología molecular en el estudio de enfermedades crónicas con base genética y nutricional / Molecular epidemiology in the study of multifactorial diseases with genetic and nutritional basis

La epidemiología genética puede ser definida como el estudio del papel de los factores genéticos y su interacción con factores ambientales en la ocurrencia de las enfermedades en poblaciones humanas. La epidemiología molecular es una disciplina relacionada con la epidemiología genética, que se caracteriza por la utilización de técnicas de biología molecular en la evaluación de la susceptibilidad genética y de los factores de riesgo de tipo ambiental que actúan sobre la tasa de incidencia de las enfermedades. La interacción entre genética y ambiente es uno de los problemas fundamentales de estudio tanto para los genetistas como para los epidemiólogos. Desde este punto de vista, el tipo de nutrición es uno de los factores de riesgo modificables. En un futuro próximo, estudios epidemiológicos de base poblacional o de base familiar, asumirán un rol de creciente importancia en la estimación de la asociación genética-enfermedad y la interacción genética-nutrición en enfermedades crónicas de etiología multifactorial