Logo do repositório

Percorrer por autor "Santos, Andrea"

A mostrar 1 - 10 de 25
  • Campylobacter em géneros alimentícios: resistências aos antimicrobianos e diversidade genética
    Publication . Santos, Andrea; Rodrigues, João Carlos; Correia, Cristina Belo; Saraiva, Margarida; Oleastro, Mónica
    Enquadramento: A campilobacteriose é considerada a principal causa de gastroenterite aguda de origem bacteriana em seres humanos, nos países desenvolvidos. Esta infeção está associada principalmente ao consumo e à contaminação cruzada de alimentos, sendo as aves o principal reservatório do agente patogénico. A utilização indiscriminada de antibióticos na produção animal e para fins veterinários, tem contribuído para o aumento do número de estirpes de Campylobacter resistentes aos antimicrobianos, e consequentemente, para o aumento do número de isolados humanos multirresistentes, motivando o estudo e a crescente preocupação das autoridades de saúde, por toda a Europa. Objetivo: Monitorizar a resistência aos antimicrobianos e avaliar a diversidade genética de estirpes de Campylobacter spp., isoladas em géneros alimentícios de produção nacional. Materiais e Métodos: Foram estudadas 29 estirpes de Campylobacter spp. isoladas em: carcaças, carne fresca e preparados de carne para serem consumidos cozinhados, provenientes de aves, suínos e bovinos. A espécie foi determinada por PCR em Tempo-Real com sondas de hibridação, a diversidade genótipica, por Multilocus sequence typing, e a resistência aos antimicrobianos, por difusão em disco. Resultados: Foram identificadas 24 estirpes da espécie Campylobacter coli (C. coli) e 5 da espécie C. jejuni. A genotipagem permitiu verificar que as estirpes de C. coli são geneticamente mais conservadas, identificando-se um complexo clonal predominante (CC-828), contrariamente ao observado para as estirpes de C. jejuni, todas de complexos clonais distintos. Foi observada uma elevada taxa de resistência aos antimicrobianos: 93.1% à ciprofloxacina, 82.8% à tetraciclina e 34.5% à eritromicina; sendo que 31% das estirpes apresentaram resistência aos três antibióticos testados. Conclusões: No âmbito deste estudo sublinhamos a presença de Campylobacter spp. multirresistente a antimicrobianos utilizados na terapêutica humana, em géneros alimentícios de origem animal. Reforçamos assim, a necessidade de implementar uma vigilância epidemiológica integrada da campilobacteriose em Portugal, envolvendo as vertentes humana, veterinária e alimentar.
    2013-10-31Documento de conferência Acesso aberto Ver mais
  • Campylobacter spp. in Portuguese fresh meat: use of filter membranes for the detection in food and resistance profile of the isolate
    Publication . Furtado, Rosália; Belo Correia, Cristina; Varela Flores, Cristina; Saraiva, Margarida; Santos, Andrea; Rodrigues, João Carlos; Oleastro, Mónica; Calhau, Maria Antónia
    Campylobacteriosis is considered the main cause of acute gastroenteritis in the European Union with a continuous increase in reported cases over the last five years. Due to the global increase of antibiotics use in food animals production, antibiotic resistance has became a significant threat and a public health problem. As a consequence the number of humans cases infected by multiresistant strains of Campylobacter is growing. The aim of this study was to evaluate an alternative plating media for isolation of Campylobacter spp and determine the antibiotic resistance of the isolates. According to ISO 10272-1:2006 protocol plating, two different agars are specified, being the use of a mCCDA-based medium mandatory. Therefore, two plating techniques were used in parallel: plating in mCCDA medium and the filtration technique on the surface of Columbia Blood agar. In addition, a Karmali agar or a chromogenic agar was also used. During 2012/2013, a total of 184 samples of fresh meat were analyzed and a total of 37 isolates were recovered: 30 C. coli, 7 C. jejuni. The filtration technique provided the highest number of positive results for Campylobacter spp and reduced the interference caused by the background flora, preventing the occurrence of false negative results. It showed to be a simple technique, with an improved rate of isolation and recover of this pathogen, and reduced labor and costs. All isolates were tested for ciprofloxacin, tetracycline and erythromycin resistance, using the disc diffusion method. A high rate of resistance to these antibiotics was found. We also highlight the presence of multiresistant Campylobacter in food of animal origin to antibiotics used in human therapeutic. These results increase the importance of strengthening an integrated epidemiological surveillance of campylobacteriosis, involving the areas of animal health, food production and human health.
    2014-09-03Documento de conferência Acesso restrito Ver mais
  • Characterization of Clostridium difficile 027 strains from an outbreak in a Portuguese hospital
    Publication . Antunes, Wilson; Serrano, Mónica; Santos, Andrea; Rodrigues, João; Pereira, Fátima; Oleastro, Mónica; Henriques, Adriano O.
    C. difficile infection (CDI) is the cause of an intestinal disease mediated by two potent cytotoxins, TcdA and TcdB. Symptoms of CDI can range from asymptomatic colonization or mild diarrhea, to life-threatening inflammatory lesions such as pseudomembraneous colitis, toxic megacolon or bowel perforation. In part because of the recent emergence of so-called hypervirulent strains, especially (but not exclusively) those belonging to ribotype 027, C. difficile is now considered a main nosocomial enteric pathogen. Hypervirulent epidemic strains have been associated with more severe disease conditions, with higher relapse rates and increased mortality. Health care-associated CDI develops in hospitalized patients undergoing antibiotic treatment because C. difficile can colonize the gut if the normal intestinal microbiota is disturbed. However, C. difficile is also emerging as an important pathogen in the community, as well as in animal husbandry. The organism is an obligate anaerobe, and has the ability to form spores. Spores are extremely resilient and can accumulate and remain viable in the environment or in the host for long periods of time. Spores that remain latent in the gut are responsible for the recurrence of C. difficile-associated disease (CDAD) when antibiotic therapy is stopped. At least some of the hypervirulent epidemic strains show a greater sporulation capacity in vitro, as well as robust toxin production. The first detection of C. difficile 027 hypervirulent epidemic strains implicated in a hospital outbreak in Portugal dates from January 2012, involving 12 patients, with a crude mortality rate of 50%. Here we report on the genetic characterization of those strains as well as the antibiotic resistance profile, toxin production, and rate and efficiency of spore formation. In parallel, C. difficile 027 non-outbreak strains isolated from other Portuguese health care facilities are also investigated.
    2012-11Documento de conferência Acesso aberto Ver mais
  • Clostridium difficile: diversidade genética e perfis de suscetibilidade aos antimicrobianos
    Publication . Santos, Andrea; Isidro, Joana; Júlio, Cláudia; Oleastro, Mónica
    Este trabalho teve como objetivo estudar a variabilidade genética e o perfil de suscetibilidade aos antimicrobianos de estirpes de C. difficile recebidas no Instituto Nacional de Saúde Doutor Ricardo Jorge (INSA) entre julho de 2012 e dezembro de 2014.
    2015-03Artigo científico Acesso aberto Ver mais
  • Epidemiological Data and Antimicrobial Resistance of Campylobacter spp. in Portugal from 13 Years of Surveillance
    Publication . Duarte, Andreia; Pereira, Luísa; Lemos, Maria-Leonor; Pinto, Miguel; Rodrigues, João Carlos; Matias, Rui; Santos, Andrea; PTCampyNet; Oleastro, Mónica
    This study extensively analyzed campylobacteriosis surveillance in Portugal from 2009 to 2021, aiming to investigate demographic shifts, seasonal variations, and antimicrobial resistance (AMR) within Campylobacter isolates. Surveillance network and sentinel laboratory-based system data revealed a substantial under-notification of campylobacteriosis cases, suggesting an underestimated disease burden. Notification rates exhibited a paradigm shift, with a notable prevalence among the pediatric population, particularly in children aged 1-4 years, diverging from European reports. Additionally, an emerging trend of Campylobacter infections in younger adults (15-44 years) was observed. The study unveiled a unique seasonal distribution of cases, defying typical summer peaks seen elsewhere. AMR analysis revealed high resistance to ciprofloxacin and tetracycline, in both C. jejuni (93.7% and 79.2%, respectively) and C. coli (96.5% and 93.2%, respectively), stable throughout the studied period (2013-2021). C. coli exhibited significantly higher resistance to erythromycin, gentamicin, ampicillin and ertapenem compared to C. jejuni (p < 0.001). Multilocus Sequence Typing (MLST) data demonstrated the distribution of resistance markers across diverse sequence types, challenging the notion of a clonal origin for multidrug-resistant isolates. In conclusion, the study highlights the need for enhanced surveillance and raises concerns about alarming AMR levels, recommending the implementation of whole-genome sequencing (WGS)-based surveillance for a deeper comprehension of disease patterns and an evolving AMR landscape.
    2024-02-06Artigo de investigação Acesso aberto Ver mais
  • Epidemiology of Clostridioides difficile Infection in Portugal: A Retrospective, Observational Study of Hospitalized Patients
    Publication . Nazareth, Cláudia; Leitão, Inês; Reis, Ernestina; Inácio, Hugo; Martins, Filomena; Ramalheira, Elmano; Cunha, Flávia; Santos, Carla; Lino, Sara; Moreira, Hugo; Kruptsala, Nadiya; Santos, Andrea; Paixão, Laura; Pássaro, Leonor; Oleastro, Mónica
    Introduction: Clostridioides difficile is the main cause of healthcare-associated diarrhea in Europe and North America. The aim of this study was to characterize the epidemiology and clinical burden of Clostridioides difficile infection among hospitalized patients in Portugal. Material and methods: Retrospective study conducted in six public hospital centers in Portugal. All primary Clostridioides difficile infection episodes and related recurrences occurring in 2017, as well as episodes developing two to eight weeks after the last episode diagnosed in that year, were documented. The National Reference Laboratory (National Institute of Health Dr. Ricardo Jorge) provided national surveillance data on Clostridioides difficile infection. Results: A total of 385 inpatients with at least one primary episode diagnosed in 2017 were included. Most patients were aged over 70 years-old (73.2%). The included patients developed 451 episodes during the observation period. Approximately 44% of primary episodes were community-associated. Most episodes (94.9%) occurred in patients with one or more risk factors, with recent antibiotic exposure being particularly common (86.0%). All-cause in-hospital mortality was 19.5%, being significantly higher in patients aged over 65 years-old versus those aged 18 to 64 years-old (22.4% vs 7.8%, respectively). Over 50 different ribotypes were observed among 206 Clostridioides difficile strains received by the National Reference Laboratory. Conclusion: In Portugal, hospitalized patients with Clostridioides difficile infection are mostly older patients presenting risk factors for the development of this infection, particularly recent antibiotic exposure. Mortality is disproportionately high among the older population. Community-associated Clostridioides difficile infection is common among inpatients with this infection.
    2022-04-01Artigo científico Acesso aberto Ver mais
  • Estudo da etiologia das infeções gastrintestinais agudas em crianças hospitalizadas na área de Lisboa
    Publication . Costa, Inês; Júlio, Cláudia; Rodrigues, João; Simões, Maria João; Machado, Jorge; Reis, Lúcia; Sarioglou, Konstantina; Santos, Andrea; Marques, Adelaide; Benoliel, João; Correia, Cristina; Escobar, Carlos; Silva, Tiago; Costa, Beatriz; Oliveira, Marisa; Correia, Paula; Ferreira, Gonçalo Cordeiro; Brito, Maria João; Oleastro, Mónica
    2013-02Artigo científico Acesso aberto Ver mais
  • Estudo observacional da infeção por Campylobacter spp. em doentes com diarreia aguda
    Publication . Oleastro, Mónica; Santos, Andrea; Júlio, Cláudia
    2014-06Artigo científico Acesso aberto Ver mais
  • Genome-Scale Characterization of Mycobacterium abscessus Complex Isolates from Portugal
    Publication . Carneiro, Sofia; Pinto, Miguel; Silva, Sónia; Santos, Andrea; Rodrigues, Irene; Santos, Daniela; Duarte, Sílvia; Vieira, Luís; Gomes, João Paulo; Macedo, Rita
    The Mycobacterium abscessus complex (MABC) is an emerging, difficult to treat, multidrug-resistant nontuberculous mycobacteria responsible for a wide spectrum of infections and associated with an increasing number of cases worldwide. Dominant circulating clones (DCCs) of MABC have been genetically identified as groups of strains associated with higher prevalence, higher levels of antimicrobial resistance, and worse clinical outcomes. To date, little is known about the genomic characteristics of MABC species circulating in Portugal. Here, we examined the genetic diversity and antimicrobial resistance profiles of 30 MABC strains isolated between 2014 and 2022 in Portugal. The genetic diversity of circulating MABC strains was assessed through a gene-by-gene approach (wgMLST), allowing their subspecies differentiation and the classification of isolates into DCCs. Antimicrobial resistance profiles were defined using phenotypic, molecular, and genomic approaches. The majority of isolates were resistant to at least two antimicrobials, although a poor correlation between phenotype and genotype data was observed. Portuguese genomes were highly diverse, and data suggest the existence of MABC lineages with potential international circulation or cross-border transmission. This study highlights the genetic diversity and antimicrobial resistance profile of circulating MABC isolates in Portugal while representing the first step towards the implementation of a genomic-based surveillance system for MABC at the Portuguese NIH.
    2023-10-20Artigo científico Acesso aberto Ver mais
  • Genomic Study of a Clostridium difficile Multidrug Resistant Outbreak-Related Clone Reveals Novel Determinants of Resistance
    Publication . Isidro, Joana; Menezes, Juliana; Serrano, Mónica; Borges, Vítor; Paixão, Pedro; Mimoso, Margarida; Martins, Filomena; Toscano, Cristina; Santos, Andrea; Henriques, Adriano O.; Oleastro, Mónica
    Background: Clostridium difficile infection (CDI) is prevalent in healthcare settings. The emergence of hypervirulent and antibiotic resistant strains has led to an increase in CDI incidence and frequent outbreaks. While the main virulence factors are the TcdA and TcdB toxins, antibiotic resistance is thought to play a key role in the infection by and dissemination of C. difficile. Methods: A CDI outbreak involving 12 patients was detected in a tertiary care hospital, in Lisbon, which extended from January to July, with a peak in February, in 2016. The C. difficile isolates, obtained from anaerobic culture of stool samples, were subjected to antimicrobial susceptibility testing with Etest®strips against 11 antibiotics, determination of toxin genes profile, PCR-ribotyping, multilocus variable-number tandem-repeat analysis (MLVA) and whole genome sequencing (WGS). Results: Of the 12 CDI cases detected, 11 isolates from 11 patients were characterized. All isolates were tcdA -/tcdB + and belonged to ribotype 017, and showed high level resistance to clindamycin, erythromycin, gentamicin, imipenem, moxifloxacin, rifampicin and tetracycline. The isolates belonged to four genetically related MLVA types, with six isolates forming a clonal cluster. Three outbreak isolates, each from a different MLVA type, were selected for WGS. Bioinformatics analysis showed the presence of several antibiotic resistance determinants, including the Thr82Ile substitution in gyrA, conferring moxifloxacin resistance, the substitutions His502Asn and Arg505Lys in rpoB for rifampicin resistance, the tetM gene, associated with tetracycline resistance, and two genes encoding putative aminoglycoside-modifying enzymes, aadE and aac(6')-aph(2″). Furthermore, a not previously described 61.3 kb putative mobile element was identified, presenting a mosaic structure and containing the genes ermG, mefA/msrD and vat, associated with macrolide, lincosamide and streptogramins resistance. A substitution found in a class B penicillin-binding protein, Cys721Ser, is thought to contribute to imipenem resistance. Conclusion: We describe an epidemic, tcdA -/tcdB +, multidrug resistant clone of C. difficile from ribotype 017 associated with a hospital outbreak, providing further evidence that the lack of TcdA does not impair the infectious potential of these strains. We identified several determinants of antimicrobial resistance, including new ones located in mobile elements, highlighting the importance of horizontal gene transfer in the pathogenicity and epidemiological success of C. difficile.
    2018-12-06Artigo científico Acesso restrito Ver mais